Details of a Researcher - Sanada, Yukitoshi

Papers - Sanada, Yukitoshi

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Frequency Resource Allocation Using Combined Evaluation Function in High Throughput Satellite Communication System

OTSURU Go, SANADA Yukitoshi, TSUJI Hiroyuki, MIURA Amane

IEICE Transactions on Communications (The Institute of Electronics, Information and Communication Engineers) E108.B ( 4 ) 531 - 539 2025.04

Joint Work, Accepted, ISSN 09168516

The resource allocation in high throughput satellites (HTSs) has been extensively investigated due to their payload ability to provide high-capacity and high-speed communication. To date, research has been conducted on variable beam arrangement using digital beamforming technology and on illumination patterns using beam hopping. In addition, there has been a great deal of research on flexible frequency resource allocation realized by digital channelizers. However, limited attention has been paid to a coordination of system throughput and fairness among user equipments (UEs) in these previous studies. In our previous paper, we proposed a frequency resource allocation model based on a beam-indexes-series finite Markov decision process. The policies of the resource allocation determined by a network operation center were only focused on maximizing either the number of allocated UEs or the system throughput. In this paper, we introduce a combined evaluation function that considers both the system throughput and the number of allocated UEs. This allows for the simultaneous optimization of communication capacity and fairness of communication opportunities. The superiority of the proposed resource allocation scheme and combined evaluation function is demonstrated through computational simulation in the comparison of the allocation scheme in the prior research. The operator is then able to coordinate the trade-off between system throughput and fairness among UEs.

Affiliation Macrocell Switching of Picocells in Uplink for Distributed Antenna System

Takada A., Sanada Y.

Proceedings of 2024 IEEE 29th Asia Pacific Conference on Communications: Sustainable Connectivity: Advancing Green Technologies for a Smarter Future, APCC 2024 549 - 554 2024.11

Joint Work, Last author, Accepted

This paper proposes the affiliation macrocell switching of picocells in a distributed antenna system (DAS). In a conventional DAS, a macrocell is composed of a fixed number of picocells. On the other hand, in the proposed scheme, picocells can switch their affiliation to adjacent macrocells so that the throughputs of cell-edge users improve. The proposed scheme aims to improve a system throughput with the moderate increase of backhaul complexity. Numerical results obtained through computer simulation show that the proposed scheme improves the system throughput by approximately 0.3 bps/Hz/cell and maintains user fairness. Moreover, the system throughput improves regardless of the distance between distributed antennas.

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MMSE Equalization-Based MIMO Demodulation with Random Walk along Gradient Descent Direction

Kikuchiahra R., Sanada Y.

Proceedings of 2024 IEEE 29th Asia Pacific Conference on Communications: Sustainable Connectivity: Advancing Green Technologies for a Smarter Future, APCC 2024 456 - 461 2024.11

Last author, Accepted

This paper proposes a minimum mean square error (MMSE) equalization-based multi-input multi-output (MIMO) demodulation scheme with Metropolis-Hastings random walk along a gradient descent direction. The conventional scheme using intermediate search points works effectively for higherorder modulation symbols. However, its performance is deteriorated for lower-order modulation symbols. The proposed scheme suppresses the coefficients in the offdiagonal components of a channel matrix by applying MMSE equalization and improves performance in low signal-to-noise power ratio conditions even for lowerorder modulation symbols. Numerical results obtained thorough computer simulation show that the proposed scheme improves by about 2.0 dB at a bit error rate of 10-2 when the number of iteraitons is 10 for QPSK symbols with 64 transmit and receive antennas.

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Throughput Performance of Uplink Beamforming Transmission through Terminal Collaboration

Nakaoka R., Ando E., Sanada Y.

IEEE Vehicular Technology Conference 2024.10

Joint Work, Last author, Accepted, ISSN 15502252

This paper evaluates the throughput performance of uplink beamforming transmission through terminal collaboration. In the proposed scheme multiple user equipments (UEs) form a group and transmit signals synchronously to enhance the power of a received signal at a base station. The signal transmitted through terminal collaboration is selected according to proportional fairness scheduling. Thus, fairness among UEs is maintained simultaneously with system throughput improvement. Numerical results obtained through computer simulation show that the system throughput grows as the number of UEs in the group increases. It is also shown that the proposed scheme increases the system throughput by about 0.5-1.5 bps/Hz.

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Performance of User Grouping Schemes in Collaborative MIMO Reception with a Focus on User Fairness

Ando E., Sanada Y.

IEEE Vehicular Technology Conference 2024.10

Joint Work, Last author, Accepted, ISSN 15502252

This paper proposes user equipment (UE) grouping schemes that take user fairness into account in collaborative multiple-input multiple-output reception. In previous research, the criterion for UE grouping to improve system throughput is proposed. However, the user fairness is deteriorated if these schemes focus on the system throughput. In this paper, the range of the received signal power is restricted to reduce the difference among user throughput. Numerical results obtained through computer simulation show that there is a trade-off relationship between the user throughput and the user fairness via the range of the received signal power.

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Multi-User Signal Detection with UAV Relay Station in Uplink Heterogeneous Network

Furuichi M., Sanada Y.

IEEE Vehicular Technology Conference 2024.10

Joint Work, Last author, Accepted, ISSN 15502252

In this paper multi-user signal reception with an unmanned ariel vehicle (UAV) relay station (RS) in an uplink heterogeneous network is proposed. In a conventional heterogeneous network cooperative signal reception between a UAV RS and a macro base station (BS) has rarely investigated. Therefore, in this paper, minimum mean square error (MMSE) multi-user signal detection with the UAV RS and the macro BS is applied to improve a system throughput. In the proposed scheme, the UAV RS works as an amplify-and-forward relay station. The link between the UAV RS and the macro BS is assumed to be connected through a millimeter wave link. Numerical results obtained enough computer simulation show that the throughputs of both users supported by the UAV RS and the macro BS improve and a fairness index between users increases.

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Performance of Collaborative MIMO Reception with User Grouping Schemes

E. Ando and Y. Sanada,

IEICE Trans. on Commun. (The Institute of Electronics, Information and Communication Engineers) E107-B ( 1 ) 253 - 261 2024.01

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 09168516

This paper proposes user equipment (UE) grouping schemes and evaluates the performance of a scheduling scheme for each formed group in collaborative multiple-input multiple-output (MIMO) reception. In previous research, the criterion for UE grouping and the effects of group scheduling has never been presented. In the UE grouping scheme, two criteria, the base station (BS)-oriented one and the UE-oriented one, are presented. The BS-oriented full search scheme achieves ideal performance though it requires knowledge of the relative positions of all UEs. Therefore, the UE-oriented local search scheme is also proposed. As the scheduling scheme, proportional fairness scheduling is used in resource allocation for each formed group. When the number of total UEs increases, the difference in the number of UEs among groups enlarges. Numerical results obtained through computer simulation show that the throughput per user increases and the fairness among users decreases when the number of UEs in a cell increases in the proposed schemes compared to those of the conventional scheme.

Belief Propagation Detection with MRC Reception and MMSE Pre-cancellation for Overloaded MIMO

Y. Suzuki and Y. Sanada,

IEICE Trans. on Commun. (The Institute of Electronics, Information and Communication Engineers) E107-B ( 1 ) 154 - 162 2024.01

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 09168516

In this paper, belief propagation (BP) multi-input multi-output (MIMO) detection with maximum ratio combining (MRC) and minimum mean square error (MMSE) pre-cancellation is proposed for overload MIMO. The proposed scheme applies MRC before MMSE pre-cancellation. The BP MIMO detection with MMSE pre-cancellation leads to a reduction in diversity gain due to the decreased number of connections between variable nodes and observation nodes in a factor graph. MRC increases the diversity gain and contributes to improve bit error rate (BER) performance. Numerical results obtained through computer simulation show that the BERs of the proposed BP MIMO detection with MRC and MMSE pre-cancellation yields bit error rates (BERs) that are approximately 0.5dB better than those of conventional BP MIMO detection with MMSE pre-cancellation at a BER of 10-3.

Gradient Descent Direction Random Walk MIMO Detection using Intermediate Search Point

N. Ito and Y. Sanada

IEICE Trans. on Commun. E106-B ( 11 ) 1192 - 1199 2023.11

Last author, Accepted

Gain and Output Optimization Scheme for Block Low-Resolution DACs in Massive MIMO Downlink

T. Yamakado and Y. Sanada

IEICE Trans. on Commun. (The Institute of Electronics, Information and Communication Engineers) E106-B ( 11 ) 1200 - 1209 2023.11

Research paper (scientific journal), Last author, Accepted, ISSN 09168516

In this paper, a nonlinear quantized precoding scheme for low-resolution digital-analog converters (DACs) in a massive multiple-input multiple-output (MIMO) system is proposed. The nonlinear quantized precoding determines transmit antenna outputs with a transmit symbol and channel state information. In a full-digital massive MIMO system, low-resolution DACs are used to suppress power consumption. Conventional precoding algorithms for low-resolution DACs do not optimize transmit antenna gains individually. Thus, in this paper, a precoding scheme that optimizes individual transmit antenna gains as well as the DAC outputs is proposed. In the proposed scheme, the subarray of massive MIMO antennas is treated virtually as a single antenna element. Numerical results obtained through computer simulation show that the proposed precoding scheme achieves bit error rate performance close to that of the conventional precoding scheme with much smaller antenna gains on a CDL-A channel.

Adaptive Mixing Probability Scheme in Mixed Gibbs Sampling MIMO Signal Detection

K. Chuman and Y. Sanada

IEICE Trans. on Commun. (The Institute of Electronics, Information and Communication Engineers) E106-B ( 12 ) 1463 - 1469 2023.11

Last author, Accepted, ISSN 09168516

This paper proposes an adaptive mixing probability scheme for mixed Gibbs sampling (MGS) or MGS with maximum ratio combining (MRC) in multiple-input multiple-output (MIMO) demodulation. In the conventional MGS algorithm, the mixing probability is fixed. Thus, if a search point is captured by a local minimum, it takes a larger number of samples to escape. In the proposed scheme, the mixing probability is increased when a candidate transmit symbol vector is captured by a local minimum. Using the adaptive mixing probability, the numbers of candidate transmit symbol vectors searched by demodulation algorithms increase. The proposed scheme in MGS as well as MGS with MRC reduces an error floor level as compared with the conventional scheme. Numerical results obtained through computer simulation show that the bit error rates of the MGS as well as the MGS with MRC reduces by about 1/100 when the number of iterations is 100 in a 64×64 MIMO system.

Frequency Resource Allocation Using Q-learning for User Link in High Throughput Satellite Communication

G. Otsuru, Y. Sanada, H. Tsuji, and A. Miura

The 26th International Symposium on Wireless Personal Multimedia Communications 2023.11

Research paper (international conference proceedings), Accepted

Belief Propagation Overloaded MIMO Detection using MRC Reception and MMSE Pre-cancellation

Y. Suzuki and Y. Sanada

IEEE 98th Vehicular Technology Conference 2023.10

Research paper (international conference proceedings), Last author, Accepted, ISSN 15502252

In this paper, belief propagation (BP) multi-input multi-output (MIMO) detection with maximum ratio combining (MRC) and minimum mean square error (MMSE) pre-cancellation is proposed for overload MIMO. In the proposed scheme, MRC is applied before MMSE pre-cancellation. The BP MIMO detection with MMSE pre-cancellation leads to a reduction in diversity gain due to the decreased number of connections between variable nodes and observation nodes in a factor graph. MRC increases the diversity gain and contributes to the improvement of bit error rate (BER) performance. Numerical results obtained through computer simulation show that the BERs of the proposed BP MIMO detection with MRC and MMSE pre-cancellation are about 0.5 dB better than those of the conventional BP with MMSE pre-cancellation at a BER of 10-3.

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Index Modulation Scheme Using Sparse Perfect Gaussian Integer Sequences on Multicarrier System

K. Yamazaki and Y. Sanada

IEEE 98th Vehicular Technology Conference 2023.10

Research paper (international conference proceedings), Accepted, ISSN 15502252

This paper proposes a new index modulation (IM) scheme for a multi-carrier system, in which spreading codes are selected by index bits. In the proposed scheme OFDM transmission is carried out without spreading codes on some of the subcarriers. At the same time, IM with spreading codes is applied. One of the spreading codes corresponding to index bits is selected in each subcarrier, and the selected code is modulated with assigned coding bits. By increasing the number of coding bits transmitted at a time, the coding rate of the system is reduced, and the overall performance is improved. The OFDM signal and the spreading signal by IM co-exists and interfere with each other. At a receiver, soft replica symbols are generated from the soft output of a demodulator or a decoder and subtracted from the received signal to cancel the interference. Numerical results obtained through computer simulation results show the performance improvement of about 3.0 dB at a bit error rate of 10-4 compared with the conventional multicarrier transmission and 6-path Rayleigh fading channels.

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User Scheduling at Base Station Cluster Boundary for Massive MIMO Downlink Transmission

YATA Masahito, SANADA Yukitoshi

IEICE Transactions on Communications (The Institute of Electronics, Information and Communication Engineers) E106-B ( 7 ) 586 - 594 2023.09

Research paper (scientific journal), Last author, Accepted, ISSN 09168516

One of the key technologies for the fifth-generation (5G) mobile communication system is massive multiple-input multiple-output (MIMO) that applies beamforming in order to effectively compensate for large propagation losses in high frequency bands and enable the spatial multiplexing of a large number of signal streams over multiple users. To further improve a system throughput, a coordinated cluster system in which a large number of massive MIMO base stations are deployed in high density has been investigated. The dense deployment greatly improves the system capacity by controlling base stations from a centralized base band unit. However, when clusters are closely located in order to serve densely populated areas, inter-beam interference between adjacent clusters becomes more severe. To suppress the interference to adjacent clusters, only a simple beam switch control scheme at a cluster boundary has been investigated as a conventional scheme. In this paper, the scheduling algorithm for massive MIMO downlink transmission near cluster boundaries, which combines two scheduling algorithms, has been proposed. In the proposed scheme, each base station divides its own cell to multiple areas, switches supporting areas sequentially, and serves users in those areas. The numerical results show that the throughputs improve with a little reduction in a fairness index (FI) when the number of users per resource block is one. The FI reaches the highest when the number of users per cell is equal to the number of divided areas. The proposed scheme reduces computational complexity as compared with those of conventional two schemes.

Double CRC-Aided Erasure Demodulation on M-ary Chirp Spread Spectrum Signal

E. Ando and Y. Sanada

URSI General Assembly and Scientific Symposium 2023 2023.08

Research paper (international conference proceedings), Last author, Accepted

UE Set Selection for RR Scheduling in Distributed Antenna Transmission with Reinforcement Learning

OTSURU Go, SANADA Yukitoshi

IEICE Transactions on Communications (The Institute of Electronics, Information and Communication Engineers) E106-B ( 7 ) 586 - 594 2023.07

Research paper (scientific journal), Accepted, ISSN 09168516

In this paper, user set selection in the allocation sequences of round-robin (RR) scheduling for distributed antenna transmission with block diagonalization (BD) pre-coding is proposed. In prior research, the initial phase selection of user equipment allocation sequences in RR scheduling has been investigated. The performance of the proposed RR scheduling is inferior to that of proportional fair (PF) scheduling under severe intra-cell interference. In this paper, the multi-input multi-output technology with BD pre-coding is applied. Furthermore, the user equipment (UE) sets in the allocation sequences are eliminated with reinforcement learning. After the modification of a RR allocation sequence, no estimated throughput calculation for UE set selection is required. Numerical results obtained through computer simulation show that the maximum selection, one of the criteria for initial phase selection, outperforms the weighted PF scheduling in a restricted realm in terms of the computational complexity, fairness, and throughput.

Precoding and Gain Adjustment Scheme for Block LowResolution DACs in Massive MIMO Downlink

T. Yamakado and Y. Sanada

IEEE 97th Vehicular Technology Conference 2023-June 2023.06

Research paper (international conference proceedings), Joint Work, Last author, Accepted, ISSN 15502252

In this paper, a nonlinear quantized precoding and gain adjustment scheme for low-resolution digital-analog converters (DACs) in a massive multiple-input multiple-output (MIMO) system is proposed. The nonlinear quantized precoding determines transmit antenna outputs with a transmit symbol and channel state information. In a full-digital massive MIMO system, low-resolution DACs are used to suppress power consumption. Conventional precoding algorithms for low-resolution DACs do not optimize transmit antenna gains individually. Thus, in this paper, a gain adjustment scheme that optimizes individual transmit antenna gains and the DAC outputs of a virtual block antenna formed by multiple antennas is proposed. Numerical results obtained through computer simulation show that the proposed precoding scheme achieves bit error rate performance close to that of the conventional Gibbs sampling based algorithm with much smaller antenna gains on a i.i.d Rayleigh fading channel.

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Attribution Macro Cell Switching for CoMP in Distributed Antenna Transmission

T. Tsukamoto, G. Otsuru, and Y. Sanada

IEEE 97th Vehicular Technology Conference 2023-June 2023.06

Research paper (international conference proceedings), Last author, Accepted, ISSN 15502252

In this paper, coordinated multi-point transmission (CoMP) with attribution macro cell switching in distributed antenna transmission is proposed. The proposed scheme is applied to a macro cell system in which each macro cell consists of multiple micro cells. In the proposed scheme, macro cells can be expanded and overlapped with each other, and each micro cell may switch its attribution macro cell. Inter-cell interference is mitigated in conjunction with CoMP transmission. Numerical results obtained through computer simulation show that the largest improvement in a system throughput is realized with three user equipments per macro cell when an inter-antenna distance is 50 meters. The switching frequency corresponds to the amount of the improvement in the throughput. The switching happens less frequently with a longer inter-antenna distance. Thus, the proposed scheme improves the system throughput than the conventional scheme in a dense distributed antenna system.

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【続編】Raspberry PiとSCRATCHでロボットを動かそう（3） Scratch プログラミング編

Sanada Yukitoshi

IEICE Communications Society Magazine (The Institute of Electronics, Information and Communication Engineers) 17 ( 1 ) 6 - 10 2023

Gradient Descent Direction Random Walk MIMO Detection using Intermediate Search Point

ITO Naoki, SANADA Yukitoshi

(ICETC 2022) 2022.11

Research paper (international conference proceedings), Joint Work, Last author, Accepted

Reduction of Out-of-Band Radiation with Quantized Precoding using Gibbs Sampling in Massive MU-MIMO-OFDM

YAMAKADO Taichi, OKAWA Riki, SANADA Yukitoshi

IEICE Transactions on Communications (The Institute of Electronics, Information and Communication Engineers) E105-B ( 10 ) 1240 - 1248 2022.10

Research paper (scientific journal), Accepted, ISSN 0916-8516

Pilot Signal Design for Mixed Numerology NOMA Transmission

Kanke H., Sanada Y., Matsuda H., Takahashi M., Kimura R.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2022-September 2022.09

Research paper (international conference proceedings), Accepted, ISSN 15502252

In the fifth-generation mobile communication system (5G) mixed numerology is standardized to meet the requirements of various services. In this paper, mixed numerology signal transmission in which multiple signals with different numerologies is assumed. As a conventional pilot signal, demodulation reference signal (DMRS) in a forth generation mobile communication (4G) is applied. However, under mixed numerology non-orthogonal multiple access (NOMA), DMRS can not realize orthogonality between pilot signals. As a solution, new pilot signal design based on a Zadoff-Chu sequence is proposed. The proposed pilot signal assignment scheme improves orthogonality between signals with different numerologies and, as a result, reduces bit error rate (BER) performance. Numerical results obtained through computer simulation show that the proposed pilot signal assignment scheme improves the performance by about 2.0 dB at a BER of 10{-2}.

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User Scheduling at Base Station Cluster Boundary for Massive MIMO Downlink Transmission

YATA Masahito, SANADA Yukitoshi

(URSI-JSRM 2022) 2022.09

Last author

[Paper] Performance of Cell-Free Distributed Antenna System with Adaptive-Resolution ADCs

Gao Peng, Sanada Yukitoshi

ITE Transactions on Media Technology and Applications (The Institute of Image Information and Television Engineers) 10 ( 3 ) 90 - 99 2022.07

ISSN 2186-7364

In this paper, we propose a cell-free distributed antenna system (DAS) architecture with adaptive resolution-(AR-) analog-to-digital converters (ADCs) in access points (APs). The proposed scheme adopts accurate models of the combined effects of clipping, quantization, and thermal noise in the ADC to analyze the quantization characteristics with different resolutions at different received signal-to-interference-and-noise ratios (SINRs). The proposed resolution bit selection criterion of the AR-ADC scheme is then applied. The AR-ADC scheme is to minimize the ADC resolution bits under allowable quantization distortion, and obtain the corresponding optimal clipping factor of the signal-to-interference-plus-quantization-and-noise ratio (SIQNR) for the desired received signal. The contributions of this paper are as follows; 1) the AR-ADC scheme provides a receiver architecture that realizes better energy efficiency (EE), 2) the spectral efficiency (SE) performance is improved by allocating more resolution bits to the APs closer to each UE with the proposed criterion. Numerical results demonstrate that the proposed AR-ADC scheme improves the EE more than tenfold as compared with the other schemes except the system with only 1-bit ADCs. Moreover, the proposed AR-ADC doubles the SE as compared with the system with only 1-bit ADCs.

BP MIMO Detection with MMSE Pre-cancellation Sub-matrix Switching

Imamura T., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2022-June 2022.05

ISSN 15502252

In this paper, belief propagation (BP) multiple-input multiple-output (MIMO) detection with minimum mean square error (MMSE) pre-cancellation matrix switching in overloaded MIMO systems is proposed. Loops in a factor graph degrades the demodulation performance of the BP scheme. Therefore, several schemes that suppresses the negative impact of loopy BP have been proposed. Among them, the application of MMSE pre-cancellation prior to BP has been proposed. In the scheme, the effects of loops in the factor graph is suppressed by MMSE pre-cancellation. However, many loops with large coefficients remain in the factor graph even after MMSE pre-cancellation. Therefore, the proposed scheme applies MMSE pre-cancellation matrix switching every after a preset number of BP iterations in order to suppress the occurrence of large beliefs in the loops. Numerical results obtained through computer simulation show that the proposed scheme achieves better BER performance than BP with MMSE pre-cancellation without matrix switching. The proposed scheme outperforms the conventional without switching by 0.7 dB at BER= 10-3.

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Macro Cell Switching of Transmit Antennas in Distributed Antenna Transmission

TSUKAMOTO Takahito, OTSURU Go, SANADA Yukitoshi

IEICE Transactions on Communications (The Institute of Electronics, Information and Communication Engineers) E105.B ( 3 ) 302 - 308 2022.03

ISSN 0916-8516

In this paper, a macro cell switching scheme for distributed antennas is proposed. In conventional distributed antenna transmission (DAT), the macro cell to which each antenna belongs is fixed. Though a cell-free system has been investigated because of its higher system throughput, the implementation cost of front-hauls can be excessive. To increase the flexibility of resource allocation in the DAT with moderate front-haul complexity, we propose the macro cell switching of distributed antennas (DAs). In the proposed scheme, DAs switch their attribution macro cells depending on the amount of pre-assigned connections. Numerical results obtained through computer simulation show that the proposed scheme realizes a better system throughput than the conventional system, especially when the number of user equipments (UEs) is smaller and the distance between DAs are larger.

Ground-based Radio Placement Determination Method Based on Analysis of Curved Section Propagation Characteristics in 45 GHz band Train Radio System of the Shinkansen

MATSUMURA Yoshihiro, TANGE Tomoyuki, NISHIYAMA Takeshi, SASAKI Eishi, IWAMOTO Koki, NAKAMURA Kazuki, ARAKAWA Tomoki, IGURA Hiroyuki, SANADA Yukitoshi

電子情報通信学会論文誌B 通信 (電子情報通信学会) J105-B ( 3 ) 362 - 374 2022.03

Two-Stage Belief Propagation Detection with MMSE Pre-Cancellation for Overloaded MIMO

SHIOI Risa, IMAMURA Takashi, SANADA Yukitoshi

IEICE Transactions on Communications (The Institute of Electronics, Information and Communication Engineers) E105.B ( 3 ) 309 - 317 2022.03

ISSN 0916-8516

In this paper, two-stage BP detection is proposed for overloaded MIMO. The proposal combines BP with the MMSE pre-cancellation algorithm followed by normal BP detection. In overloaded MIMO systems, the loops in a factor graph degrade the demodulation performance of BP detection. MMSE pre-cancellation reduces the number of connections or coefficient values in the factor graph which improves the convergence characteristics of posteriori probabilities. Numerical results obtained through computer simulation show that the BERs of the proposed two-stage BP detection outperforms the conventional BP with MMSE pre-cancellation in a low bit energy range when the MMSE block size is four and the number of MMSE blocks is one. When the pre-cancellation is applied for complexity reduction, the proposed scheme reduces multiplication operations and summation operations by the same factor of 0.7 though the amount of the performance improvement to the conventional scheme is limited.

Attribution Macro Cell Switching in Distributed Antenna Transmission

Tsukamoto T., Otsuru G., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2021-September 2022.03

ISSN 15502252

In this paper, a macro cell switching scheme for distributed antennas is proposed. In conventional distributed antenna transmission (DAT), a macro cell to which each antenna belongs is fixed. Though a cell-free system has been investigated because of its higher system throughput, the complexity of front-haul can be inevitably large. To increase the flexibility of resource allocation in the DAT with moderate front-haul complexity, the macro cell switching of distributed antennas (DAs) is proposed. In the proposed scheme, DAs switch their attribution macro cells depending on the amount of pre-assigned resources. Numerical results obtained through computer simulation show that the proposed scheme realizes a better system throughput than the conventional system especially when the number of user equipments (UEs) is smaller.

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Power-Based Criteria for Signal Reconstruction using 1-bit Resolution DACs in Massive MU-MIMO OFDM Downlink

OKAWA Riki, SANADA Yukitoshi

IEICE Transactions on Communications (一般社団法人電子情報通信学会) 2021.10

ISSN 0916-8516

The sum rate and bit error rate (BER) performance of nonlinier quantized precoding using Gibbs sampling are evaluated in a massive multiuser multiple-input multiple-output (MU-MIMO) system in this paper. Massive MU-MIMO is a key technology to handle the growth of data traffic. In a full digital massive MU-MIMO system, however, the resolution of digital-to-analogue converters (DACs) in transmit antenna branches have to be low to yield acceptable power consumption. Thus, a combinational optimization problem is solved for the nonlinier quantized precoding to determine transmit signals from finite alphabets output from low resolution DACs. A conventional optimization criterion minimizes errors between desired signals and received signals at user equipments (UEs). However, the system sum rate may decrease as it increases the transmit power. This paper proposes two optimization criteria that take the transmit power into account in order to maximize the sum rate. Mixed Gibbs sampling is applied to obtain the suboptimal solution of the nonlinear optimization problem. Numerical results obtained through computer simulations show that the two proposed criteria achieve higher sum rates than the conventional criterion. On the other hand, the sum rate criterion achieves the largest sum rate while it leads to less throughputs than the MMSE criterion on approximately 60% of subcarriers.

Likelihood-based Metric for Gibbs Sampling Turbo MIMO Detection

KOBAYASHI Yutaro, SANADA Yukitoshi

IEICE Transactions on Communications (一般社団法人電子情報通信学会) 2021.09

ISSN 0916-8516

In a multiple-input multiple-output (MIMO) system, maximum likelihood detection (MLD) is the best demodulation scheme if no a priori information is available. However, the complexity of MLD increases exponentially with the number of signal streams. Therefore, various demodulation schemes with less complexity have been proposed and some of those schemes show performance close to that of MLD. One kind of those schemes uses a Gibbs sampling (GS) algorithm. GS MIMO detection that combines feedback from turbo decoding has been proposed. In this scheme, the accuracy of GS MIMO detection is improved by feeding back loglikelihood ratios (LLRs) from a turbo decoder. In this paper, GS MIMO detection using only feedback LLRs from a turbo decoder is proposed. Through extrinsic information transfer (EXIT) chart analysis, it is shown that the EXIT curves with and without metrics calculated from received signals overlap as the feedback LLR values increase. Therefore, the proposed scheme calculates the metrics from received signals only for the first GS MIMO detection and the selection probabilities of GS MIMO detection in the following iterations are calculated based only on the LLRs from turbo decoders. Numerical results obtained through computer simulation show that the performance of proposed GS turbo MIMO detection is worse than that of conventional GS turbo MIMO detection when the number of GS iterations is small. However the performance improves as the number of GS iterations increases. When the number of GS iterations is 30 or more, the bit error rate (BER) performance of the proposed scheme is equivalent to that of the conventional scheme. Therefore, the proposed scheme can reduce the computational complexity of selection probability calculation in GS turbo MIMO detection.

Two-Stage Belief Propagation Detection with MMSE Pre-Cancellation for Overloaded MIMO

Shioi R., Imamura T., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2021-September 2021.09

ISSN 15502252

In this paper, two-stage BP detection is proposed for overloaded MIMO. In the two-stage BP detection scheme, the BP with MMSE pre-cancellation algorithm followed by the normal BP detection is applied. In overloaded MIMO systems, the loops in a factor graph degrade the demodulation performance of BP detection. MMSE pre-cancellation reduces the number of connections or coefficient values in the factor graph and improves the convergence characteristics of posteriori probabilities. Numerical results obtained through computer simulation have shown that the BERs of the proposed two-stage BP detection are about 1.0-1.5dB better than those of the conventional BP with MMSE pre-cancellation when the MMSE block size is four and the number of MMSE blocks is one.

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Weight Adjustment in Channel Estimation using Gibbs Sampling for MIMO Systems

Chuman K., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2021-September 2021.09

ISSN 15502252

Channel estimation is required to demodulate the multiple-input multiple-output (MIMO) signals and there are blind and non-blind channel estimation schemes. One of non-blind channel estimation schemes is using Gibbs sampling. In channel estimation using Gibbs sampling, when the number of received data symbols is small, estimation accuracy may be deteriorated owing to the unreliability of weights. In order to solve this problem, this paper introduces a coefficient for adjusting the weights used in channel estimation with Gibbs sampling. When the number of data symbols is small, larger coefficient values are found to be more suitable because they suppress the fluctuation of channel estimation. Numerical results obtained though computer simulation show that the proposed scheme improves by about 5dB as compared with a decision directed scheme in a 4 × 4 MIMO system when the number of data symbols is one.

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Quantized Precoding for Out-of-Band Radiation Reduction in Massive MU-MIMO-OFDM

Yamakado T., Okawa R., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2021-September 2021.09

ISSN 15502252

In this paper, a non-linear precoding algorithm with low out-of-band (OOB) radiation in a massive multiple-input multiple-output (MIMO) system is proposed. Massive MIMO is a system with more than a few hundred antennas implemented in a base station and is characterized by better spectral efficiency and higher throughput. Full digital massive MIMO may require lower resolution in digital-to-analog converters (DACs) since each high-resolution DAC consumes a large amount of power. In massive MIMO systems with low resolution DACs, an output signal designed by nonlinear processing has been investigated. The conventional scheme focuses only on a sum rate or errors in received signals and causes large OOB radiation. This paper proposes an optimization criterion that takes OOB radiation power into account. Gibbs sampling is used as an algorithm to search for a sub-optimal solution for this criterion. Numerical results obtained through computer simulation show that the proposed criterion reduces the mean OOB radiation power by a factor of 10 as compared with the conventional criteria. Furthermore, the proposed criterion achieves larger sum rate over all subcarriers as compared with an error based criterion. On the other hand, as compared with a sum rate based criterion, the throughput on each subcarrier shows less variation and that demands a smaller number of link adaptation options although the average sum rate of the proposed criterion is smaller.

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Performance of CRC-Aided Erasure Demodulation for M-ary Chirp Spread Spectrum Signal

Sanada Y., Ono T.

17th IEEE VTS Asia Pacific Wireless Communications Symposium, APWCS 2021 - Proceedings (17th IEEE VTS Asia Pacific Wireless Communications Symposium, APWCS 2021 - Proceedings) 2021.08

In this paper, erasure demodulation for an M-ary chirp spread spectrum signal is proposed. This demodulation scheme is assumed to be implemented in IoT devices to receive a deactivation command. In the erasure demodulation scheme a demodulator regards bit elements in a coded bit sequence as erasure if the corresponding correlator output is larger than a threshold and they are different from bit elements in a coded bit sequence for the maximum correlator output. Those erasure bits are treated as both "0"and "1"and cyclic redundancy check (CRC) decoding following the erasure demodulation checks which output is correct. As one of those outputs must be the same as the transmit coded bit, block error rate (BLER) performance improves. Even though the erasure demodulation increases the probability of false alarm, it can reduce the miss probability of deactivation. On the other hand, as the number of erasure bits increases, the number of CRC decoding operations grows exponentially and the probability of CRC miss detection also increases. Thus, the threshold level has to be decided according to the computational capability of each IoT device, the target BLER, and the probability of CRC miss detection. The performance of CRC miss detection and the BLER on a Rayleigh fading channel, a Rician fading channel, and a Vehicular-B channel are evaluated through computer simulation. Furthermore, cumulative distribution function curves for the number of erasure bits are also presented for different channel models.

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Forcible search scheme for mixed gibbs sampling massive mimo detection

YAMAZAKI K., SANADA Y.

IEICE Transactions on Communications (IEICE Transactions on Communications) E104.B ( 4 ) 419 - 427 2021.04

ISSN 09168516

In this paper, mixed Gibbs sampling multiple-input multiple-output (MIMO) detection with forcible search is proposed. In conventional Gibbs sampling MIMO detection, the problem of stalling occurs under high signal-to-noise ratios (SNRs) which degrades the detection performance. Mixed Gibbs sampling (MGS) is one solution to this problem. In MGS, random sampling is carried out with a constant probability regardless of whether a current search falls into a local minimum. In the proposed scheme, combined with MGS, multiple candidate symbols are forcibly changed when the search is captured by a local minimum. The search restarts away from the local minimum which effectively enlarges the search area in the solution space. Numerical results obtained through computer simulation show that the proposed scheme achieves better performance in a large scale MIMO system with QPSK signals.

User scheduling with beam selection for full digital massive mimo base station

YATA M., OTSURU G., SANADA Y.

IEICE Transactions on Communications (IEICE Transactions on Communications) E104.B ( 4 ) 428 - 435 2021.04

ISSN 09168516

In this paper, user scheduling with beam selection for fulldigital massive multi-input multi-output (MIMO) is proposed. Inter-user interference (IUI) can be canceled by precoding such as zero-forcing at a massive MIMO base station if ideal hardware implementation is assumed. However, owing to the non-ideal characteristics of hardware components, IUI occurs among multiple user terminals allocated on the same resource. Thus, in the proposed scheme, the directions of beams for allocated user terminals are adjusted to maximize the total user throughput. User allocation based on the user throughput after the adjustment of beam directivity is then carried out. Numerical results obtained through computer simulation show that when the number of user terminals in the cell is two and the number of user terminals allocated to one resource block (RB) is two, the throughput per subcarrier per subframe improves by about 3.0 bits. On the other hand, the fairness index (FI) is reduced by 0.03. This is because only the probability in the high throughput region increases as shown in the cumulative distribution function (CDF) of throughput per user. Also, as the number of user terminals in the cell increases, the amount of improvement in throughput decreases. As the number of allocated user terminals increases, more user terminals are allocated to the cell-edge, which reduces the average throughput.

User Set Elimination in Allocation Sequences of RR Scheduling for Distributed Antenna Transmission

Otsuru G., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2021-April 2021.04

ISSN 15502252

In this paper, user set elimination in the allocation sequences of round-robin (RR) scheduling for distributed antenna transmission (DAT) is proposed. In prior research, the initial phase selection of the user equipment (UE) allocation sequences in RR scheduling has been investigated. However, all of UE sets are included without taking their throughputs into account. Thus, a UE set is assigned even through its total throughput is the lowest. The proposed scheme eliminates the specific UE sets from the RR scheduling sequence according to the expected total throughput of those UE sets. In addition, the initial phase selection is applied to the remaining UE sets. Numerical results obtained through computer simulation show that fairness index as well as system throughput improve when the ratio of eliminated UE sets is small.

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Low complexity overloaded MIMO detection based on belief propagation with MMSE pre-cancellation

Imamura T., Sanada Y.

IEICE Transactions on Communications (IEICE Transactions on Communications) E104B ( 3 ) 312 - 319 2021.03

ISSN 09168516

In this paper, the application of minimum mean square error (MMSE) pre-cancellation prior to belief propagation (BP) is proposed as a detection scheme for overloaded multiple-input multiple-output (MIMO) systems. In overloaded MIMO systems, the loops in the factor graph degrade the demodulation performance of BP. Therefore, the proposed scheme applies MMSE pre-cancellation prior to BP and reduces the number of loops. Furthermore, it is applied to the selected transmit and receive nodes so that the condition number of an inverse matrix in the MMSE weight matrix is minimized to suppress the residual interference and the noise after MMSE pre-cancellation. Numerical results obtained through computer simulation show that the proposed scheme achieves better bit error rate (BER) performance than BP without MMSE pre-cancellation. The proposed scheme improves the BER performance by 2.9-5.6 dB at a BER of 5.0 × 10− compared with conventional BP. Numerical results also show that MMSE pre-cancellation reduces the complexity of BP by a factor of 896 in terms of the number of multiplication operations. 3

Miniaturization and Test Results of Shinkansen Antenna for Overhead Line Voltage Detection and Wireless Communication

MATSUMURA Yoshihiro, NISHIYAMA Takeshi, SASAKI Eishi, NISHIMOTO Kengo, AKUTSU Hiroyuki, SANADA Yukitoshi

電子情報通信学会論文誌B 通信 (電子情報通信学会) J104-B ( 1 ) 42 - 53 2021.01

The Shinkansen antenna for overhead line voltage detection and wireless communication antenna has both the function of detecting the overhead line voltage of 60 Hz and the function of wireless communication in the VHF band. The antenna installed on the roof of the leading car on the Tokaido Shinkansen has been unchanged since its opening, despite being one of the sources of noise. In order to reduce noise, it is necessary to shorten the detection rod that detects overhead line voltage. Therefore, we propose a miniaturized antenna configuration that uses a folded monopole structure and a parallel resonant circuit. When the detection rod is shortened, the performance of overhead line voltage detection deteriorates, but the deterioration is minimized by making the antenna substrate area as large as possible within the antenna radome shape that reduces noise. We confirm the effectiveness of the proposed antenna by simulations and measurements. Moreover, we investigate the influence of the snow and rain, and show the results evaluated by running test.

Forcible search with mixed gibbs sampling massive MIMO detection

Yamazaki K., Sanada Y.

IEEE Region 10 Annual International Conference, Proceedings/TENCON (IEEE Region 10 Annual International Conference, Proceedings/TENCON) 2020-November 292 - 296 2020.11

ISSN 9781728184555

In this paper, mixed Gibbs sampling multiple- input multiple-output (MIMO) detection with forcible search is proposed. In conventional Gibbs sampling MIMO detection, the problem of stalling occurs under high signal-to-noise ratios (SNRs) which degrades the detection performance. Mixed GS (MGS) is one solution to this problem. In the MGS, random sampling is carried out with a constant probability without judging if a current search is at a local minimum. In the proposed scheme, combined with MGS, multiple candidate symbols are forcibly changed when the search is captured by a local minimum. The search restarts away from the local minimum which effectively enlarges the search area in a solution space. Numerical results obtained through computer simulation show that the proposed scheme achieves better performance in a large scale MIMO system with QPSK signals.

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MIMO detection with block parallel gibbs sampling and maximum ratio combining

Tomura K., Sanada Y., Kobayashi Y.

IEEE Region 10 Annual International Conference, Proceedings/TENCON (IEEE Region 10 Annual International Conference, Proceedings/TENCON) 2020-November 496 - 500 2020.11

ISSN 9781728184555

In this paper, block parallel Gibbs sampling (BPGS) multiple-input multiple-output (MIMO) detection is proposed. In a conventional Gibbs sampling scheme, MIMO detection is carried out sequentially symbol-by-symbol. The proposed scheme divides a symbol vector to blocks and updates candidate transmit symbols in parallel in a block so that the total number of iterations in a unit period increases. Furthermore, maximum ratio combining (MRC) is adopted to BPGS to improve accuracy in this paper. Numerical results obtained through computer simulations show that bit error rate performance under high bit-energy-to-noise-spectrum-density conditions improves with the proposed scheme. It is also shown that the block size of three achieves the best performance when number of antennas is 16×16 and the number of iterations is 50.

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Performance evaluation of miniaturized antenna of the shinkansen used for overhead line voltage detection and wireless communication

Matsumura Y., Sasaki E., Nishiyama T., Nishimoto K., Akutsu H., Sanada Y.

International Symposium on Wireless Personal Multimedia Communications, WPMC (International Symposium on Wireless Personal Multimedia Communications, WPMC) 2020-October 2020.10

ISSN 9781728182964

Reducing the noise from the sound of train travel is an important issue in high-speed railways such as the Shinkansen. There has been no change in the shape of the antenna installed on the roof on the leading car of the Tokaido Shinkansen since the line started service, even though this is a source of the noise. Here, by changing (miniaturizing) the shape of this antenna from the standpoint of noise countermeasures, we developed an antenna that satisfied both the overhead line voltage detection performance and wireless detection performance, analyzed its performance by examination in factory and running tests, and confirmed that it can be provided for practical use. In this paper, we report a summary of the antenna, the results of the performance evaluation under environments of rain and accumulated snow, and the results of performance evaluation by running tests.

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Phase selection in round-robin scheduling sequence for distributed antenna system

Otsuru G., Sanada Y.

IEICE Transactions on Communications (IEICE Transactions on Communications) E103B ( 10 ) 1155 - 1163 2020.10

ISSN 09168516

One of key technologies in the fifth generation mobile communications is a distributed antenna system (DAS). As DAS creates tightly packed antenna arrangements, inter-user interference degrades its spectrum efficiency. Round-robin (RR) scheduling is known as a scheme that achieves a good trade-off between computational complexity and spectrum efficiency. This paper proposes a user equipment (UE) allocation scheme for RR scheduling. The proposed scheme offers low complexity as the phase of UE allocation sequences are predetermined. Four different phase selection criteria are compared in this paper. Numerical results obtained through computer simulation show that maximum selection, which sequentially searches for the phase with the maximum tentative throughput realizes the best spectrum efficiency next to full search. There is an optimum number of UEs which obtains the largest throughput in single-user allocation while the system throughput improves as the number of UEs increases in 2-user RR scheduling.

Low Complexity Belief Propagation based MIMO Detection with MMSE Pre-cancellation for Overloaded MIMO systems

Imamura T., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2020.09

Last author

In this paper, the application of minimum mean square error (MMSE) pre-cancellation prior to belief propagation (BP) is proposed as a detection scheme for overloaded multiple-input multiple-output (MIMO). In overloaded MIMO, the loops in a factor graph deteriorate the demodulation performance with BP. Therefore, the proposed scheme applies the MMSE pre-cancellation prior to BP and reduces the number of the loops. Furthermore, it is applied to the selected transmit and receive nodes so that the condition number of an inverse matrix in the MMSE weight matrix is minimized in order to suppress the residual interference and the noise after the MMSE precancellation. It is shown by numerical results obtained through computer simulation that the proposed scheme achieves better bit error rate (BER) performance than BP without the MMSE pre-cancellation. The proposed scheme improves the BER performance by 4.6-5.0 dB at a BER of 5.0 × 10-3 as compared with conventional BP. Numerical results also shows that the MMSE pre-cancellation reduces the complexity in BP by a factor of 1/896 in terms of the number of multiplication operations.

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Novel approximated zero forcing pre-coding technique with threshold for diffusion based molecular communication

Sohail Ahsan, Sanada Yukitoshi

IEICE Communications Express (一般社団法人電子情報通信学会) 9 ( 7 ) 348 - 353 2020.07

ISSN 2187-0136

This letter proposes approximated zero forcing precoding with a threshold in molecular communication (MC). Frequency domain precoding for channel equalization is investigated. Owing to the restriction of a transmitter in MC the main part of an equalized waveform is extracted and a corresponding rectangular waveform is transmitted. In the proposed equalization scheme, the frequency component of the transmit signal is suppressed if a threshold exceeds the channel coefficient in the proposed scheme. Numerical results obtained through computer simulation show that approximation by a single rectangular waveform achieves almost the same performance as that with rectangular approximation that suppresses inter-symbol interference with the proposed precoding technique.

Precoder Design Algorithm using Spatial Signal Synthesis with Multiple Antenna Subset Selection for Hybrid MIMO System

Tamate D., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2020-May 2020.05

ISSN 9781728152073

In this paper, a precoder design algorithm using spatial signal synthesis with selected multiple antenna subsets for hybrid multiple-input multiple-out-put (MIMO) systems is proposed. The hybrid MIMO systems are expected to be implemented in high frequency bands. To reduce power consumption and increase the bandwidth of a transmit signal, the resolution of phase shifters and the number of quantization levels in digital-analog (D/A) converters have to be limited. A baseband precoder needs to take the effect of quantization into account. On the other hand, when the number of transmit antennas is larger than that of receive antennas, spatial signal synthesis can be realized. The selection of antenna sets also needs to take the effect of quantization into account. In this paper, a transmit antenna selection scheme that improves the spectral efficiency by spatial signal synthesis with multiple antenna subsets is proposed. Numerical results obtained through computer simulation show that the proposed scheme with two antenna subsets of four transmit antennas and two receive antennas improves the spectrum efficiency by about 1.0 bit/s/Hz when the number of transmit and receive are 4.

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Novel frequency domain equalization with threshold for molecular communication

Sohail Ahsan, Sanada Yukitoshi

IEICE Communications Express (一般社団法人電子情報通信学会) 9 ( 2 ) 36 - 41 2020.02

ISSN 2187-0136

This letter proposes a frequency domain equalization (FDE) scheme with a threshold in molecular communication (MC). The responses of a MC channel are tendency to have low pass characteristics and inter-symbol interference limits the data rates of MC. However, because of the characteristics of the MC channel, equalization coefficients for high frequency components may increase. Therefore, noise enhancement occurs and it deteriorates communication performance. As large channel responses concentrate at around a zero-frequency component, in the proposed equalization scheme, the high frequency component of the received signal is eliminated if the equalization coefficient exceeds a threshold in the proposed scheme. Numerical results obtained through computer simulation show that the threshold improves the communication performance with the proposed FDE. It is also shown that the trade-off between the noise enhancement and the pulse waveform effects on the performance.

Detection schemes for massive MIMO system with low-resolution ADCs

Gao Peng, Sanada Yukitoshi

IEICE Communications Express (一般社団法人電子情報通信学会) 8 ( 10 ) 422 - 427 2019.10

ISSN 2187-0136

In a full-digital massive multi-user MIMO system, maximal-ratio combining (MRC) can obtain more considerable diversity gain while inter-stream interference (ISI) and multi-user interference (MUI) can be canceled using minimum mean square error (MMSE) algorithm. This letter evaluates the throughputs of detection schemes for different antenna numbers in the massive MIMO system with low-resolution analog-to-digital converters (ADCs). The letter makes a comparison between MRC and MMSE under quantization range limit. Numerical results show that MRC achieves better system performance with lower implementation complexity as the number of antennas increases.

Convergence improvement in repeating weighted boosting search algorithm for channel estimation

Taniguchi Y., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2019-September 2019.09

ISSN 9781728112206

The fifth generation mobile communication systems are expected to support the Internet-of-Things (IoT) applications. One of the problems in massive connections is the assignment of pilot sequences. For supporting a large number of the IoT devices, non- orthogonal sequences have to be assigned and a receiver in a base station needs to estimate channel impulse responses (CIRs) by solving a joint optimization problem. In this paper, a new channel estimation scheme for the IoT devices is proposed. The proposed scheme is based on a repeating weighted boosting search algorithm and modifies the generation process of candidate CIR vectors for faster convergence in search iterations. Instead of calculating the sum of weighted candidate CIR vectors, the proposed scheme generates a candidate CIR vector that is assumed to be closer to the global optimum. In this case, the proposed scheme improves the convergence rate as compared to the conventional scheme though the mean square errors (MSE) of the solutions is worse. If the number of subcarriers is limited, the MSE of the estimated CIR vectors with the proposed algorithm is equivalent to that with the conventional scheme. Thus, the proposed scheme is less complex and suitable for massive connections. Numerical results obtained through computer simulation have shown that the proposed scheme achieves faster convergence by about 17-35% as compared to the conventional scheme.

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Latency of uplink non-orthogonal multiple access grant-free transmission with multiuser detection in base station

Shiono S., Sanada Y., Kimura R., Matsuda H., Sawai R.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2019-September 2019.09

ISSN 9781728112206

In this paper, the latency of non-orthogonal multiple access (NOMA) grant-free (GF) transmission in uplink is evaluated by link and system level simulations. In order to cancel interference among NOMA signals, multiuser detection (MUD) consisting of minimum mean square error demodulation followed by successive interference cancellation is applied. Retransmission happens only when a packet error occurs after serial interference cancellation (SIC). Therefore, the latency is reduced as compared to GF transmission without MUD. Numerical results obtained through system level simulation show that the application of MUD in uplink GF transmission improves the latency and increases the successful transmission rate without retransmission by a factor of about 3.0.

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User allocation with round-robin scheduling sequence for distributed antenna system

Otsuru G., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2019-September 2019.09

ISSN 9781728112206

One of key technologies in the fifth generation mobile communications is a distributed antenna system (DAS). In the DAS inter-user interference effects on its spectrum efficiency as distributed antennas are located closely. Round-robin (RR) scheduling is known as a scheme that achieves a trade-off between computational complexity and spectrum efficiency. In this research user equipment (UE) allocation scheme for RR scheduling are proposed. The proposed scheme determines the phases of UE allocation sequence that is pre-determined for low complexity. Numerical results obtained through computer simulation have shown that maximum selection that sequentially searches the phase with the maximum tentative throughput realizes the largest spectrum efficiency next to full search. The system throughput increases as the number of UEs increases in 2-user RR scheduling.

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Effect of quantization range limit for low-resolution analog-to-digital converters in full-digital massive MIMO system

Gao P., Sanada Y.

Proceedings - 2019 IEEE VTS Asia Pacific Wireless Communications Symposium, APWCS 2019 (Proceedings - 2019 IEEE VTS Asia Pacific Wireless Communications Symposium, APWCS 2019) 2019.08

ISSN 9781728112046

Low-resolution analog-to-digital converters (ADCs) may need to be implemented in a full-digital massive multi-user MIMO system for low-power consumption. In this paper, the performance with a proposed ADC design for low-resolution ADCs to suppress the amount of degradation due to the quantization process in the full-digital massive multi-user MIMO system is evaluated. In the proposed ADC design, quantization range limit is specified based on the mean amplitude of a received signal and the input amplitude is bounded to eliminate thermal noise. Numerical results show that, through clipping the thermal noise by setting the appropriate quantization range limit, the full-digital massive MIMO with low-resolution ADCs (even 1-bit ADCs) realizes better system throughput than that with infinite-resolution ADCs. It is also shown that the throughput with low-resolution ADCs is equivalent to that with infinite-resolution ADCs when the number of users is less than three (the number of streams is less than six).

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Quantized Precoding using Gibbs Sampling in Massive MIMO Downlink

Okawa R., Sanada Y.

Proceedings - 2019 IEEE VTS Asia Pacific Wireless Communications Symposium, APWCS 2019 (Proceedings - 2019 IEEE VTS Asia Pacific Wireless Communications Symposium, APWCS 2019) 2019.08

ISSN 9781728112046

The sum rate performance of quantized precoding using Gibbs sampling is evaluated in a massive multiple-input multiple-output (MIMO) system in this paper. The massive MIMO is a promising technique to improve spectrum efficiency and energy efficiency. In a full digital massive MIMO system, however, the resolution of digital-to-analogue converters (DACs) in transmit antenna branches have to be low enough because of their power consumption. Therefore, quantized precoding or precoding with the low resolution DACs is investigated. A conventional optimization criterion minimizes errors between a desired received signal and a designed signal. However, the system sum rate may decrease as it increases transmit power. This paper proposes two optimization criteria that take not only the errors but also the transmit power into account to select the candidate quantized transmit signal in order to maximize the sum rate. Moreover, Gibbs sampling is applied to obtain the suboptimal solution of the optimization problem. Numerical results obtained through computer simulation show that the proposed sum rate based criterion for the optimization achieves the approximately 1.3 times higher sum rate than the conventional criterion on a Rician fading channel. On the other hand, the proposed symbol-power-to-mean-square-error ratio (SMSER) based criterion shows faster optimization convergence.

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Effect of Joint Detection on System Throughput in Distributed Antenna Network

Ishikawa Haruya, Sanada Yukitoshi

IEICE TRANSACTIONS ON COMMUNICATIONS E102B ( 3 ) 641 - 647 2019.03

ISSN 0916-8516

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Mixed Gibbs sampling iterative MIMO detection and decoding with maximum ratio combining

Kobayashi Y., Sanada Y.

2019 URSI Asia-Pacific Radio Science Conference, AP-RASC 2019 (2019 URSI Asia-Pacific Radio Science Conference, AP-RASC 2019) 2019.03

ISSN 9789082598759

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Non-orthogonal multiple access with joint maximum likelihood detection in heterogeneous network

Sanada Yukitoshi

EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING (Eurasip Journal on Wireless Communications and Networking) 2018 ( 1 ) 2018.12

ISSN 1687-1472

As one of the key technologies in the fifth-generation mobile communication system, non-orthogonal multiple access (NOMA) has been investigated. In NOMA, multiple terminals are assigned the same frequency resources by a scheduler on the basis of the difference in propagation losses between a base station and user terminals. Each terminal cancels the signals for the other terminals and extracts its desired signal. On the other hand, the application of joint maximum likelihood (ML) detection to overloaded signals has also been investigated, and joint ML detection can be applied to a NOMA downlink. In this paper, the effect of joint ML detection in a heterogeneous NOMA network is presented. The numerical results obtained through system-level simulation show that joint ML detection in a heterogeneous NOMA downlink can effectively offload mobile traffic from a macro base station to a pico base station. It is shown that a heterogeneous NOMA network with joint ML detection improves the throughput performance by 0.2 bit/user/subcarrier as compared to that without joint ML detection at a cumulative probability of 0.5. The system throughput is also increased about twofold with joint ML detection.

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Performance of MMSE interference rejection followed by joint MLD for DAN

Miyagi H., Sanada Y.

IEICE Transactions on Communications (IEICE Transactions on Communications) E101B ( 12 ) 2471 - 2478 2018.12

ISSN 09168516

Copyright © 2018 The Institute of Electronics, Information and Communication Engineers. This paper applies minimum mean square error (MMSE) interference rejection followed by joint maximum likelihood detection (MLD) to a receiver in a distributed antenna network (DAN).DANreceivers capture not only the desired signals, but also the interference signals from nearby uncoordinated antennas. For the overloaded signal situation, nonlinear detection schemes such as joint MLD can be applied to the received signals. However, the amount of metric calculations in joint MLD increases exponentially with the number of signal streams. Therefore, MMSE interference rejection followed by MLD detection is proposed. The proposed scheme reduces the complexity by a factor of 1=2M (NT -1) where NT is the number of interference signals with 2MQAM modulation. The effect of residual interference after the MMSE interference rejection is evaluated. Numerical results obtained through computer simulation and experiment show that the performance of the proposed scheme is about 4:0 dB worse at a bit error rate (BER) of 10-3 than that of the joint MLD while its complexity is four times lower for QPSK signal streams. The BER performance degradation can be suppressed to about 2:5 dB by adjusting the value of the coefficient in the MMSE matrix.

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MU-MIMO-OFDM with Analog Beamforming and Spreading Codes for User Separation

Nakahara K., Terui K., Sanada Y.

ISPACS 2018 - 2018 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS 2018 - 2018 International Symposium on Intelligent Signal Processing and Communication Systems) 96 - 101 2018.11

ISSN 9781538657713

This paper presents a multiuser (MU)-multiple-input multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) scheme that realizes signal separation among mobile terminals by spreading codes on top of analog beamforming with analog-digital hybrid massive MIMO. Multiuser MIMO scheme suffers from interference among terminals caused by inaccurate information of channel responses. The channel state information (CSI) of the terminals are outdated owing to a Doppler shift if there is a time lag between channel estimation and CSI feedback. Thus, this paper proposes an MU-MIMO-OFDM scheme with analog-digital hybrid massive MIMO and orthogonal spreading codes that separates signals for mobile terminals. Numerical results obtained through computer simulation show that on WINNER II Umi NLOS channel the proposed scheme improves bit error rate (BER) performance by 1.0dB at a bit error rate of 10 in comparison with the conventional MU-MIMO. -3

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Downlink Performance of MRT-BD in Multiuser Massive MIMO with Low Resolution ADCs

Gao P., Sanada Y.

IEEE 5G World Forum, 5GWF 2018 - Conference Proceedings (IEEE 5G World Forum, 5GWF 2018 - Conference Proceedings) 52 - 59 2018.10

ISSN 9781538649824

© 2018 IEEE. The multiuser massive MIMO (multi-input multi-output) system using the low-resolution analog-to-digital converters (ADCs) in the uplink is to realize low cost and power consumption demands, which, however, reduce the signal quality. Beamforming as a signal processing technique can supply high throughputs in the MIMO systems. In this paper, we investigate the robustness of low-resolution ADCs against the interference among the different streams in the uplink and the different users in downlink systems respectively, and propose the maximum ratio transmission - block diagonalization (MRT-BD) scheme as a kind of beamforming to evaluate the effects of low-resolution ADCs in the full digital massive MIMO system. The preliminary conclusion is that the MRT-BD scheme achieves our anticipation to make the rate achievable, even more than it in the infinite-resolution (no quantization) of BD case can be approached using ADCs with only a few bits of resolution.

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Low Complexity Metric Function for Gibbs Sampling MIMO Detection

Kobayashi Y., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2018-August 2018.07

ISSN 9781538663585

In this paper, a metric function for Gibbs sampling multiple-input multiple-output (MIMO) detection is proposed. In conventional Gibbs sampling MIMO detection, an exponential function is used in the calculation of a metric for the selection of candidate symbols. However, the exponential function can be implemented by a look-up table and may require a large amount of memory. This paper proposes a metric function based on a simple fraction. The proposed metric substitutes the exponential function though it increases the number of multiplication operations. It is shown by numerical results obtained through computer simulation that the proposed metric function improves the performance under a high signal-to-noise ratio condition in a large scale MIMO system since its curve is close to that of the exponential function when an input metric distance approaches to zero.

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System Throughput Analysis on Using Joint Detection in Distributed Antenna System

Ishikawa H., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2018-August 2018.07

ISSN 9781538663585

Throughput analysis of the usage of joint maximum-likelihood detection (MLD) in a distributed antenna system (DAS) with multiple mobile terminal scheduling is evaluated in this paper. In DAS, mobile terminals are closer to desired antennas which improves system throughput and increases frequency utilization efficiency. However, since there are more antennas in a cell, interference can occur between transmitted signals from the antennas when multiple mobile terminals are scheduled. Therefore, we propose a novel mobile terminal scheduling method and the use of joint MLD to reduce the effects of interference. A system level simulation shows that the usage of joint MLD in densely packed DAS provides better system throughput.

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Precoder Design Algorithm for Hybrid MIMO System with Discrete Phase Shifters and D/A Converters

Tamate D., Sanada Y.

IEEE Vehicular Technology Conference (IEEE Vehicular Technology Conference) 2018-August 2018.07

ISSN 9781538663585

In this paper, a precoder design algorithm using Gibbs sampling for hybrid multiple-input multiple-output (MIMO) systems is proposed. The hybrid MIMO systems are expected to be implemented in high frequency bands. To reduce power consumption and increase the bandwidth of a transmit signal, the number of phase shifters and the number of quatntization levels in digital-analog (D/A) converters have to be limited. A baseband precoder needs to take the effect of quantization into account. Owing to the quantization, it is difficult for a conventional precoder design algorithm with orthogonal matching pursuit (OMP) to reach the optimal solution. On the other hand, the proposed precoder design algorithm using Gibbs sampling is robust to quantization errors. Numerical results obtained through computer simulation show that the proposed algorithm achieves spectral efficiency of 50 bit/s/Hz at a signal-to-noise ration of 20 dB for a quantization level of 24 on an independent Rayleigh fading channel.

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Special Section on Communication Quality in Wireless Networks FOREWORD

Sanada Yukitoshi

IEICE TRANSACTIONS ON COMMUNICATIONS E101B ( 7 ) 1522 - 1522 2018.07

ISSN 0916-8516

Low Complexity Log-Likelihood Ratio Calculation Scheme with Bit Shifts and Summations

Y. Aoki, K. Matsugi, and Y. Sanada

IEICE Trans. on Communications E101-B ( 3 ) 731 - 739 2018.03

Research paper (scientific journal), Joint Work, Accepted

Expanded Precoding Index Modulation for MIMO System

NIN Yasunori, SANADA Yukitoshi, KIMURA Ryota, MATSUDA Hiroki, SAWAI Ryo

IEICE Transactions on Communications (一般社団法人電子情報通信学会) E102B ( 4 ) 921 - 929 2018

ISSN 0916-8516

Index modulation (IM) is receiving attention because of its high energy efficiency. In precoding index modulation (PIM), some of the data bits are used for the modulation of symbols and the rest are used for the selection of precoding coefficients. In conventional PIM, the precoding matrices are orthogonal and unitary. In the proposed PIM, the number of the columns of the precoding matrix is expanded more than that of the rows. Because of the expanded precoding matrices, the number of data bits used for the selection of precoding coefficients is increased. As a result, a code rate can be reduced compared to that of the conventional PIM and the number of candidate constellation points for demodulation can be decreased as compared to that of a multiple-input multiple-output MIMO system under the same throughput. Numerical results obtained through computer simulation show that the proposed PIM with QPSK symbols improves the performance by about 2.5 dB at a bit error rate of 10-3 as compared to overloaded MIMO with 16QAM symbols for two transmit antennas and one receive antenna. It also achieves about 3.5 dB better performance than the conventional PIM under the same antenna condition. Furthermore, the optimum number of index modulation bits is found by the simulation for the proposed PIM. In addition, the PIM scheme reduces demodulation complexity by a factor of 32 as compared to that of the MIMO under specific modulation parameters.

Transmit Beam Selection Scheme for Massive MIMO using Expected Beam Responses

KUBO Yoshihito, SANADA Yukitoshi

IEICE Transactions on Communications (一般社団法人電子情報通信学会) E102B ( 4 ) 913 - 920 2018

ISSN 0916-8516

Massive multiple-input multiple-output (MIMO) realizes simultaneous transmission to a large number of mobile stations (MSs) and improves frequency utilization efficiency. It is drawing attention as the key technology of the fifth-generation (5G) mobile communication systems. The 5G system is going to be implemented in a high frequency band and massive MIMO beamforming (BF) is applied to compensate propagation loss. In the conventional BF scheme, a transmit beam is selected based on the power of received signals over subcarriers. The signal on a different subcarrier is transmitted with a different directivity. To improve the accuracy of beam selection, this paper proposes a transmit beam selection scheme for massive MIMO. The proposed scheme calculates the expected responses of the signals over the subcarriers based on the relative directivity between a base station (BS) and a MS. The MS calculates the correlation between the received signals and each of the expected response sequences. It then selects the beam with the highest correlation value. It is shown in this paper that the proposed scheme can improve the average signal-to-noise ratio of a received signal by about 1.5dB as compared with that of the power based search scheme. It is also shown that the proposed scheme with limited response coefficients can reduce the computational complexity by a factor of 1/100 while it still increases the average SNR by about 1.0dB.

FOREWORD

SANADA Yukitoshi

IEICE Transactions on Communications (一般社団法人電子情報通信学会) 101 ( 7 ) 1522 - 1522 2018

ISSN 0916-8516

Timing Synchronization Performance of Preamble Signal with Orthogonal Frequency Multiplexed Data Signal in the Presence of Frequency Offset

T. Kitano, Y. Tanaka, and Y. Sanada

Wireless Personal Communications 96 ( 4 ) 5499 - 5514 2017.10

Research paper (scientific journal), Joint Work, Accepted

Correlation Reduction Precoding for Joint Decoding in Overloaded MIMO-OFDM System on Rician Channel

T. Yabe and Y. Sanada

Wireless Personal Communications 96 ( 3 ) 3785 - 3798 2017.10

Research paper (scientific journal), Joint Work, Accepted

Cyclic Delay Diversity with Phase Shift in Low Rate SC-FDMA Uplink

Y. Enjyoji and Y. Sanada

Wireless Personal Communications 96 ( 4 ) 5743 - 5755 2017.10

Research paper (scientific journal), Joint Work, Accepted

Performance Comparison of Overloaded MIMO System with and without Antenna Selection

Y. Nin, H. Matsuoka, and Y. Sanada

IEICE Trans. on Communications E100-B ( 5 ) 762 - 770 2017.02

Research paper (scientific journal), Joint Work, Accepted

Throughput Performance of Non-orthogonal Multiple Access with Joint Detection in Far User,

T. Yazaki and Y. Sanada

IEICE Trans. on Communications E100-B ( 2 ) 344 - 353 2017.02

Research paper (scientific journal), Joint Work, Accepted

Ricianフェージング環境におけるターボ符号とプレコーディング係数を用いた過負荷MIMO-OFDMシステムの特性検討

Y. Miyagi and Y. Sanada

映像情報メディア学会誌 71 ( 2 ) 68 - 73 2017.02

Research paper (scientific journal), Accepted

Joint Turbo Decoding for Overloaded MIMO-OFDM Systems

I. Shubhi and Y. Sanada

IEEE Trans. on Vehicular Technology 66 ( 1 ) 433 - 442 2017.01

Research paper (scientific journal), Joint Work, Accepted

Joint Maximum Likelihood Detection in Far User of Non-orthogonal Multiple Access

K. Ando and Y. Sanada

IEICE Trans. on Communications E100-B ( 1 ) 177 - 186 2017.01

Research paper (scientific journal), Joint Work, Accepted

Shift Estimation with Delayed Correlation Cyclic-Selectinve Mapping PAPR Reduction in OFDM System

P. D. Pamungkasari and Y. Sanada

Wireless Personal Communications, 91 ( 2 ) 739 - 753 2016.11

Research paper (scientific journal), Accepted

Effect of Signal Cancelation in Far User on Non-orthogonal Multiple Access Downlink

T. Yazaki and Y．Sanada

Wireless Personal Communications 89 ( 4 ) 1203 - 1219 2016.08

Research paper (scientific journal), Joint Work, Accepted

Pseudo Distance for Trellis Coded Modulation in Overloaded MIMO OFDM With Sphere Decoding

I. Shubhi and Y. Sanada

Trans. on Communications E99-B ( 3 ) 723 - 731 2016.03

Research paper (scientific journal), Joint Work, Accepted

Mitigation of Antenna Displacement with Array Antenna for Data Transmission in Wireless Power Transfer System

M. Iida and Y. Sanada

International Journal of Wireless Information Networks 23 ( 1 ) 19 - 27 2016.03

Research paper (scientific journal), Joint Work, Accepted

Low Complexity Metric for Joint MLD in Overloaded MIMO System

T. Aoki and Y. Sanada

IEICE Trans. on Communications E99-B ( 2 ) 447 - 454 2016.02

Research paper (scientific journal), Joint Work, Accepted

Open-Loop Correlation Reduction Precoding in Overloaded MIMO-OFDM Systems

H. Matsuoka, Y. Doi, T. Yabe, and Y. Sanada

IEICE Trans. on Communications E99-B ( 1 ) 202 - 210 2016.01

Joint Work, Accepted

Phase and Gain Imbalance Compensation in Low-IF Receivers

T. Ide, T. Fujii, M. Inamori, and Y. Sanada

IEICE Trans. on Communications E99-B ( 1 ) 211 - 222 2016.01

Research paper (scientific journal), Joint Work, Accepted

Estimation of Cyclic Shift with Delayed Correlation and Matched Filtering in Time Domain Cyclic-SLM for PAPR Reduction

P. D. Pamungkasari and Y. Sanada

International Scholarly Research Notices 2016 2016

Research paper (scientific journal), Joint Work, Accepted

Codeword Metric Calculation Scheme for Outer Code in Overloaded MIMO-OFDM System2015.

Y. Doi and Y. Sanada

IEICE Trans. on Communications E98-B ( 8 ) 1598 - 1605 2015.08

Joint Work, Accepted

Delayed Correlation Based Signal Detection Scheme with Filter Bank for OFDM Signal,"

H. Odani, R. Takai, S Uchida, and Y. Sanada

IEICE Trans. on Communications E98-B ( 7 ) 1381 - 1389 2015.07

Joint Work, Accepted

Window Functions for Frame Correlation Reduction in Overlapped FFT based Energy Detection

R. Takai, S Uchida, and, Y. Sanada

IEICE Trans. on Communications E98-B ( 3 ) 485 - 493 2015.03

Research paper (scientific journal), Joint Work, Accepted

Data Transmission using Transmitter Side Channel Estimation in Wireless Power Transfer System

K. Sugeno, M. Inamori, and Y. Sanada

IEICE Trans. on Fundamentals (IEICE) E98-A ( 2 ) 589 - 596 2015.02

Research paper (scientific journal), Accepted

Performance of Overloaded MIMO-OFDM System with Repetition Code

H. Matsuoka, Y. Doi, T. Yabe, and Y. Sanada

IEICE Trans. on Commun. (IEICE) E97-B ( 12 ) 2767 - 2775 2014.12

Joint Work, Accepted

Timing Synchronization Performance of Short Preamble Sequence with Orthogonal Frequency Multiplexed Data Symbols

Y. Tanaka and Y. Sanada

IEICE Trans. on Fundamentals (IEICE) E97-A ( 11 ) 2097 - 2106 2014.11

Research paper (scientific journal), Joint Work, Accepted

Signal Detection Performance of Overlapped FFT Scheme with Additional Frames Consisting of Non-continuous Samples in Indoor Environment

S. Uchida, A. Sato, M. Inamori, Y. Sanada, and M. Ghavami

Wireless Personal Communications (Springer) 79 ( 2 ) 987 - 1002 2014.11

Research paper (scientific journal), Joint Work, Accepted

Experimental Investigation of Signal Sensing with Overlapped FFT based Energy Detection

R. Takai, S. Uchida, A. Sato, and Y. Sanada

Wireless Personal Communications 77 ( 1 ) 553 - 569 2014.07

Joint Work, Accepted

Two Step Timing Synchronization Scheme for OFDM Signal in General Purpose Processor Based Software Defined Radio Receiver

Y. Tanaka, M. Inamori, and Y. Sanada

Wireless Personal Communications 79 ( 1 ) 363 - 374 2014.06

Joint Work, Accepted

Complexity Reduction in Joint Decoding of Block Coded Signals in Overloaded MIMO-OFDM System

Y. Doi, M. Inamori, and Y. Sanada

IEICE Trans. on Communications E97-B ( 4 ) 905 - 914 2014.04

Joint Work, Accepted

Performane Investigation of Data Transmission in Wireless Power Transfer with Coil Displaceements

M. Iida, K. Sugeno, and Y. Sanada

IEICE Trans. on Fundamentals E97-A ( 4 ) 1016 - 1020 2014.04

Research paper (scientific journal), Joint Work, Accepted

Experimental Investigation of Joint Decoding in Overloaded MIMO-OFDM System

T. Yabe, M. Inamori, and Y. Sanada

IEICE Trans. on Communications E96-B ( 12 ) 3101 - 3107 2013.12

Joint Work, Accepted

Adjacent Channel Interference Cancellation using Orthogonal Precoding for Fractional Sampling OFDM Receiver

E. Sakai, H. Nishimura, M. Inamori, and Y. Sanada

Wireless Personal Communications 72 ( 1 ) 211 - 225 2013.09

Research paper (scientific journal), Joint Work, Accepted

Effect of Load Fluctuation in Data Transmission for Wireless Power Transfer

K. Sugeno, A. Noguchi, M. Inamori, and, Y. Sanada

IEICE Trans. on Fundamentals E96-A ( 5 ) 991 - 994 2013.05

Research paper (scientific journal), Joint Work, Accepted

Precoded Transmit Path Diversity in FS-OFDM on UWB Channels

H. Nishimura, M. Inamori, Y. Sanada, and M. Ghavami

Wireless Personal Communications 68 ( 3 ) 711-725 2013.02

Research paper (scientific journal), Joint Work, Accepted

Reliable Data Transmission for Resonant-type Wireless Power Transfer

A. Noguchi, M. Inamori, and Y. Sanada

IEICE Trans. on Fundamentals E96-A ( 1 ) 298-303 2013.01

Research paper (scientific journal), Joint Work, Accepted

Non-orthogonal Access Scheme over Multiple Channels with Iterative Interference Cancellation and Fractional Sampling in OFDM Receiver

H. Osada, M. Inamori, and Y. Sanada

IEICE Trans. on Communications E95-B ( 12 ) 3837-3844 2012.12

Research paper (scientific journal), Joint Work, Accepted

Improvement of Multipath Delay Resolution with Imaging Components on Separate Frequency Channel in Fractional Sampling OFDM

H. Nishimura, M. Inamori, Y. Sanada, and M. Ghavami

IEICE Trans. on Fundamentals E95-A ( 11 ) 1971-1979 2012.11

Research paper (scientific journal), Joint Work, Accepted

Low-Complexity Cyclostationarity Detection Scheme of Localized SC-FDMA Uplink System for Application to Detect and Avoid

W. Zhang and Y. Sanada

Wireless Personal Communications 66 ( 2 ) 307-319 2012.09

Research paper (scientific journal), Joint Work, Accepted

Frequency Offset Amplify-and-Forward Relay in OFDM System

A. Suzuki, Y. Sanada, and M. Inamori

IEICE Trans. on Communications E94-B ( 12 ) 3289-3295 2011.12

Research paper (scientific journal), Joint Work, Accepted

Fractional Samplingを用いたIEEE802.11n受信機

SANADA YUKITOSHI

光電技法 ( 27 ) 2-8 2011.10

Research paper (bulletin of university, research institution), Single Work

RAKE受信方式の原理と発展

SANADA YUKITOSHI

電子情報通信学会基礎・境界ソサイエティFundamentals Review 5 ( 11 ) 20-27 2011.07

Research paper (scientific journal), Single Work

Dual-stage Detection Scheme for Ultra-Wideband Detect and Avoid

W. Zhang and Y. Sanada

IEICE Trans. on Fundamentals E94-A ( 4 ) 1124-1132 2011.04

Research paper (scientific journal), Joint Work, Accepted

Non-uniform Sampling Point Selection in OFDM Receiver with Fractional Sampling

H. Nishimura, M. Inamori, Y. Sanada, and M. Ghavami

IET Trans. on Communications 5 ( 4 ) 554-562 2011.04

Research paper (scientific journal), Joint Work, Accepted

Performance Analysis of OFDM Repeater Networks with Spatial Fading Correlation

R. C. Kizilirmak and Y. Sanada

Wireless Personal Communications 56 ( 3 ) 573-582 2011.02

Research paper (scientific journal), Joint Work, Accepted

Time Domain Feedback Equalizer for Fast Fading Channel in OFDM with Scattered Pilot

T. Kobayashi, H. Nishimura, and Y. Sanada

IEICE Trans. on Fundamentals E93-A ( 12 ) 2691-2695 2010.12

Research paper (scientific journal), Joint Work, Accepted

Sampling Point Selection Scheme for Fractional Sampling-OFDM Receivers on Fast Time-Varying Multipath Channels

T. Kobayashi, H. Nishimura, and Y. Sanada

IEICE Trans. on Fundamentals E93-A ( 11 ) 2122-2129 2010.11

Research paper (scientific journal), Joint Work, Accepted

Path Diversity with Fractional Delay Transmission for Fractional Sampling-MIMO-OFDM System

H. Higuchi and Y. SanadaS

IEICE Trans. on Fundamentals E93-A ( 11 ) 2115-2121 2010.11

Research paper (scientific journal), Joint Work, Accepted

Effect of Baseband Filter Bandwidth in Fractional Sampling OFDM on Indoor Channel Model with Measured Impulse Responses

T. Shinkai, H. Nishimura, M. Inamori, and Y. Sanada

IET Communications 4 ( 16 ) 1934-1941 2010.11

Research paper (scientific journal), Joint Work, Accepted

Correlated Noise Cancellation in Fractional Sampling OFCDM with Alternative Spreading Code

M. Inamori, H. Nishimura, Y. Sanada, and M. Ghavami

IET Communications 4 ( 10 ) 1217-1225 2010.07

Research paper (scientific journal), Joint Work, Accepted

Improvement on Diversity Gain with Filter Bandwidth Enlargement in Fractional Sampling OFDM Receiver

T. Shinkai, H. Nishimura, and Y. Sanada

IEICE Trans. on Communication E93-B ( 6 ) 1526-1533 2010.06

Research paper (scientific journal), Joint Work, Accepted

Interference Suppression in OFDM-Antenna Array with Time Shifted Sampling

H. Suzuki, R. C. Kizilirmak, and Y. SanadaSANADA

IEICE Trans. on Fundamentals E92-A ( 11 ) 2688-2696 2009.11

Research paper (scientific journal), Single Work, Accepted

IQ Imbalance Estimation Scheme in the Presence of DC Offset and Frequency Offset in the Frequency Domain

M. Inamori, S. Takayama, and Y.

IEICE Trans. on Fundamentals E92-A ( 11 ) 2688-2696 2009.11

Research paper (scientific journal), Joint Work, Accepted

Experimental Investigation of Sampling Rate Selection with Fractional Sampling for IEEE802.11b WLAN System

Y. Imaoka, and Y. Sanada

IEICE Trans. on Communication E92-B ( 10 ) 3043-3051 2009.10

Research paper (scientific journal), Joint Work, Accepted

Effect of Clock Offset on an IR-UWB Ranging System with Comparators

Y. Saito and Y. Sanada

IET Communications 3 ( 6 ) 1024-1029 2009.06

Research paper (scientific journal), Joint Work, Accepted

Effect of Pulse Shaping Filters on a Fractional Sampling OFDM System with Subcarrier-Based Maximal Ratio Combining

M. Inamori，T. Kawai，T. Kobayashi，H. Nishimura，and Y. Sanada

IEICE Trans. on Communication E92-B ( 5 ) 1484-1494 2009.05

Research paper (scientific journal), Joint Work, Accepted

Channel Estimation with Fractional Sampling for IEEE802.11b WLAN System

Y. Imaoka, H. Obata, Y. Suzuki, and Y. Sanada

IEICE Trans. on Communications E92-B ( 3 ) 946-953 2009.03

Research paper (scientific journal), Joint Work, Accepted

超広帯域無線システムの高速化展望

眞田幸俊

電子情報通信学会ソサイエティマガジン ( 11 ) 24-31 2009

Research paper (scientific journal), Single Work

ナイキストとシャノン　～一研究室の失敗談～

眞田幸俊

電子情報通信学会ソサイエティマガジン ( 10 ) 70 2009

Research paper (scientific journal), Single Work

Analysis on IR/TR-UWB Interference against Narrowband Systems

Y. Shimizu and Y. Sanada

IEICE Trans. on Fundamentals E91-A ( 11 ) 3140-3149 2008.11

Research paper (scientific journal), Joint Work, Accepted

Multipath Diversity through Time Shifted Sampling for Spatially Correlated OFDM-Antenna Array Systems

R. C. Kizilirmak and Y. Sanada SANADA

IEICE Trans. on Fundamentals E91-A ( 11 ) 3104-3111 2008.11

Research paper (scientific journal), Joint Work, Accepted

MB-OFDMピコネットにおけるAdaptive Symbol Skippingを用いた干渉回避技術の検討

塩崎亮佑, 眞田幸俊

電子情報通信学会和文論文誌Ｂ J91-B ( 11 ) 1401-1404 2008.11

Research paper (scientific journal), Joint Work, Accepted

Sampling Rate Selection for Fractional Sampling in OFDM

H. Nishimura, M. Inamori, and Y. Sanada

IEICE Trans. on Communications E91-B ( 9 ) 2876-2882 2008.09

Research paper (scientific journal), Joint Work, Accepted

Modified Direct Insertion/Cancellation Method Based Sample Rate Conversion for Software Defined Radio

A. B. Bostamam, Y. Sanada, and H. Minami

IEICE Trans. on Communications E91-B ( 8 ) 2648-2656 2008.08

Research paper (scientific journal), Joint Work, Accepted

MMACフォーラムUWB-WGの活動状況

眞田幸俊

UWB無線システム高度化シンポジウム 2008.07

Single Work

コグニティブ無線の可能性

眞田幸俊

移動通信における電波資源拡大のための研究開発シンポジウム 2008.02

Single Work

Direct-Sequence / Spread-Spectrum Communication System with Sampling Rate Selection Diversity

Y. Suzuki, A. B. Bostamam, M. Inamori, and Y. Sanada

IEICE Trans. on Communications E91-B ( 1 ) 267-273 2008.01

Research paper (scientific journal), Joint Work

Broadband ferromagnetic resonance of Ni81Fe19 wires using a rectifying effect

A. Yamaguchi, K. Motoi, H. Miyajima, Y. Miyashita, and Y. Sanada

Physical Review B 78 104401 2008

Research paper (scientific journal), Joint Work, Accepted

Experimental Investigation of an IR-UWB Positioning System with Comparators

K. Kitamura and Y. Sanada

IEICE Trans. on Fundamentals E90-A ( 11 ) 2354-2360 2007.11

Research paper (scientific journal), Joint Work, Accepted

OFDM Interference Suppression for DS/SS Systems using Complex FIR Filter

Y. Shimizu and Y. Sanada

IEICE Trans. on Fundamentals E90-A ( 11 ) 2388-2394 2007.11

Research paper (scientific journal), Joint Work, Accepted

Frequency Offset Estimation Scheme in the Presence of Time-varying DC Offset for OFDM Direct Conversion Receivers

M. Inamori, A. B. Bostamam, Y. Sanada, and H. Minami

IEICE Trans. on Communications E90-B ( 10 ) 2884-2890 2007.10

Research paper (scientific journal), Joint Work, Accepted

Influence of Timing Jitter on Quadorature Charge Sampling

M. Inamori, A. M. Bostamam, and Y. Sanada

IET Communications 1 ( 4 ) 705-710 2007.08

Research paper (scientific journal), Joint Work, Accepted

UWB（Ultra Wide Band)の国際的標準化動向およびセンサ応用

眞田幸俊

センサエキスポジャパン2007 2007.04

Single Work

いよいよ実用化のUWB

眞田幸俊

Multmedia Mobile Access Forum 講演会 2007.02

Single Work

UWBの強制規格および標準規格

眞田幸俊

光無線通信システム推進協議会技術講演 2006.12

Single Work

IQ Imbalance Compensation Scheme for MB-OFDM with Transmit Diversity

SANADA YUKITOSHI

Trans. on Fundamentals, E89-A ( 11 ) 3026-3031 2006.11

Research paper (scientific journal), Joint Work, Accepted

Analysis on Interference Rejection of DS/SS Systems Using a Complex FIR Filter

Y. Shimizu and Y. Sanada

IEICE Trans. on Fundamentals E89-A ( 11 ) 3026-3031 2006.11

Research paper (scientific journal), Joint Work, Accepted

Experimental Investigation of Undersampling for Adjacent Channel Interference Cancellation Scheme

SANADA YUKITOSHI

IEICE Trans. on Communications E89-B ( 9 ) 2548-2542 2006.09

Research paper (scientific journal), Joint Work, Accepted

Examination of Antenna Combinations for UWB Ranging System

Y. Takeuchi, Y. Shimizu, and Y. Sanada

IEEE Trans. on MTT vol.54 ( no.4 ) 1858-1864 2006.04

Research paper (scientific journal), Joint Work

A CMOS Ultra-Wideband Impuse Radio Transceiver for 1-Mb/s Data Communications and ±2.5-cm Range Finding

T. Terada, S. Yoshizumi, M. Muqsith, Y. Sanada, and T. Kuroda

IEEE Journal of Solid-state Circuits 41 ( 4 ) pp.891-898 2006.04

Research paper (scientific journal), Joint Work, Accepted

UWBシステムの標準化および技術動向

眞田幸俊

Multimedia Mobile Access Forum 講演会 2006.03

Single Work

Decision Directed Scheme for IQ Imbalance Compensation on OFCDM Direct Conversion Receiver

T. Yuba and Y. Sanada

IEICE Trans. on Communications E89-B ( 1 ) 184-190 2006.01

Research paper (scientific journal), Joint Work, Accepted

Experiment of Analog-Digital Signal Processing for Multi-channel Reception

A. M. Bostamam and Y. Sanada

IEICE Trans. on Communications E88-B ( 6 ) 2532-2538 2005.06

Research paper (scientific journal), Joint Work, Accepted

Analog-Digital Signal Processing for Multi-channel Reception

Y. Sanada and A. M. Bostamam

IEICE Trans. on Communications E88-B ( 3 ) 1271-1273 2005.03

Research paper (scientific journal), Joint Work

Pulse Position Controlled DS-UWB

Y. Sanada

IEICE Trans. on Fundamentals E87-A ( 10 ) 2716-2718 2004.10

Research paper (scientific journal), Joint Work, Accepted

ダイレクトコンバージョン形OFCDM受信機のIQ Imbalanceによる干渉の除去

弓場廷昭，眞田幸俊

電子情報通信学会和文論文誌B J-87B ( no.6 ) pp.794-803 2004.06

Research paper (scientific journal), Single Work

Decorrelating Compensation Scheme for CoefficientErrors of a Filter Bank Parallel A/D Converter

Y. Sanada and M. Ikehara

IEEE Trans. on Wireless Communications vol.3 ( no.2 ) pp.341-347 2004.03

Research paper (scientific journal), Joint Work, Accepted

UWBシステムにおける相対位置検出特性

清水雄一郎，眞田幸俊

電子情報通信学会和文論文誌A J86-A ( No.12 ) pp.1310-1319 2003.12

Research paper (scientific journal), Joint Work, Accepted

UWBを用いたアドホックネットワークのための位置情報を利用したルーティング方式

堀江亘，眞田幸俊

電子情報通信学会和文論文誌A J86-A ( No.12 ) pp.1493-1501 2003.12

Research paper (scientific journal), Joint Work, Accepted

UWBシステムにおける変復調技術の研究開発動向

佐々木重信，眞田幸俊

2003 Microwave Workshops and Exhibition 2003.11

Research paper (conference, symposium, etc.), Joint Work

Digital Compensation Scheme for Coefficient Errors of Complex Filter Bank Parallel A/D Converter in Low-IF Receivers

Y. Sanada and M. Ikehara

IEICE Trans. on Commun E85-B ( No.12 ) 2656-2662 2002.12

Research paper (scientific journal), Joint Work, Accepted

A Software Defined RadioPlatform with Direct Conversion: SOPRANO

S. Haruyama, R. Morelos-Zaragoza, Y. Sanada

Wireless Personal Communications 23 67-76 2002.01

Research paper (scientific journal), Joint Work, Accepted

Application of the VLC Parallel Transmission Technique to Motion Vector Transmission

T. Kasai, Y. Sanada, and K. Araki

IEICE Transactions on Fundamentals Vol.E82-A ( No.12 ) 2778-2782 1999.12

Research paper (scientific journal), Joint Work, Accepted

MPEGなどの画像圧縮アルゴリズムは通常誤りの少ない有線通信を仮定している．このため無線通信路上を伝送された画像情報は，受信信号の誤りにより同期はずれを引き起こす．本論文では圧縮画像情報中の動きベクトルに着目した．そしてこの情報の符号化方式をCDMA通信用に改良し，受信信号に誤りが生じても画像の同期はずれを完全に防ぐ方法を示している．

A Novel Cumulant Based MUSIC Like DOA Estimation Algorithm withMulticarrier Modulation

Y. Sanada, J. Takada, and K. Araki

IEICE Transactions on Communications Vol.E81-B ( No.12 ) 2318-2325 1998.12

Research paper (scientific journal), Joint Work, Accepted

Performance of Adaptive Array Antennas with Multicarrier DS/CDMA in a Mobile Fading Environment

Y. Sanada, M. Padilla, and K. Araki

IEICE Transactions on Communications Vol.E81-B ( No.7 ) 1392-1400 1998.07

Research paper (scientific journal), Joint Work

適応アレーアンテナとは複数のアンテナ素子を利用し，各アンテナ素子で受信した信号に係数をかけて合成することにより空間的に干渉を除去するものである．到来波の到来方向を推定することができればアレーアンテナにおいて最適な合成係数を決定することができる．本論文ではマルチキャリアCDMA方式用の適応アレーアンテナを提案した．提案方式は信号の到来方向を誤差約2度で推定した．

A Variable Length Code TransmissioTechnique on Multicode DS/SS　Systems

Y. Sanada and K. Araki

IEICE Transactions on Communications Vol.E81-B ( No. 3 ) 625-636 1998.03

Research paper (scientific journal), Joint Work

Spread Spectrum Transmission Technique

H. Suzuki and Y. Sanada

1997 Microwave Workshops and Exhibition ( P.371-380 ) 1997.12

Research paper (conference, symposium, etc.), Joint Work

Orthogonalization using Multicarrier Pre-decorrelation in a Multipath Fading Channel

H. Matsutani, Y. Sanada, and M. Nakagawa

IEICE Transactions on Fundamentals Vol.E80-A ( No.12 ) 2470-2476 1997.12

Research paper (scientific journal), Joint Work

A Co-channel Interference Cancellatio　Technique using Orthogonal Convolutional Codes

Y. Sanada and Q. Wang

IEEE Transactions on Communications Vol.COM-44 ( No.5 ) 549-556 1997.05

Research paper (scientific journal), Joint Work

A Co-channel Interference CancellationTechnique using Orthogonal Convolutional Codes on Multipath Rayleigh Fading Channel

Y. Sanada and Q. Wang

IEEE Transactions on Vehicular Technology Vol.46 ( No.1 ) 114-128 1997.02

Joint Work

Fast Viterbi Decoding Methods for theCo-channel Interference Canceller on Cellular DS/CDMA Systems

D. Takeda, Y. Sanada, and M. Nakagawa

IEICE Transactions on Fundamentals Vol.E79-A ( No.12 ) 2002-2009 1996.12

Research paper (scientific journal), Joint Work

A Multiuser Interference Cancellation　Technique utilizing Convolutional Codes and Orthogonal Multicarrier Modulation for Wireless Indoor Communications

Y. Sanada and M. Nakagawa

IEEE Journal on Selected Areas in Communications Vol.SAC-14 ( No.8 ) 1500-1509 1996.10

Research paper (scientific journal), Joint Work

Power Control Techniques in a　Multihop CDMA Packet Radio　Network

Y. Sanada and M. Nakagawa

IEICE Transactions on Communications Vol.E79-B ( No.9 ) 1287-1294 1996.09

Research paper (scientific journal), Joint Work

パーソナル通信と直交性

中川正雄，真田幸俊

電子情報通信学会誌 (Vol.79) No.7 711-713 1996.07

Research paper (scientific journal), Single Work

A Channel Equalization Technique on a Time Division Duplex CDMA/TDMA System for Wireless Multimedia Networks

Y. Sanada, K. Seki, Q. Wang, M. Nakagawa, S. Kato, and V. K. Bhargava

IEICE Transactions on Communications Vol.E78-B ( No.8 ) 1105-1116 1995.08

Research paper (scientific journal), Joint Work

A Transmission Power Control Technique on a TDD-CDMA/TDMA　System for Wireless Multimedia Networks

Y. Sanada, K. Seki, Q. Wang, M. Nakagawa, S. Kato, and V. K. Bhargava

IEICE Transactions on Communications Vol.E78-B ( No.8 ) 1095-1104 1995.08

Research paper (scientific journal), Joint Work

A Wireless Multimedia Network on a　Time Division Duplex CDMA/TDMA

K. Seki, Y. Sanada, Q. Wang, S. Kato, and V.K. Bhargava

IEICE Transactions on Fundamentals Vol.E78-B ( No.7 ) 1002-1015 1995.07

Research paper (scientific journal), Joint Work

CDMA方式と従来から利用されている時分割多元接続（TDMA）方式を組み合わせた新しいマルチメディア通信システムの構成を提案している．提案システムはCDMA方式が比較的データレートの低く劣悪な環境における通信に向き，TDMA方式がデータレートの高く良好な環境における通信に適していることを利用している．提案システムでは，キーボードからの文字情報は必要なデータレートが低いためCDMAを用いて送信し，ディスプレイに表示するための画像情報は必要なデータレートが高いためTDMAを用いて送信される．

Adaptive RAKE Receiver for Mobile　Communications

Y. Sanada, A. Kajiwara, and M. Nakagawa

IEICE Transactions on Communications Vol.E76-B ( No.8 ) 1002-1007 1993.08

Research paper (scientific journal), Joint Work

第３世代移動通信システムに用いられるCDMA方式において新しいRAKE受信機の提案を行っている．移動体通信において，電波は地面やビルなどに反射し複数の伝搬路を通って受信機に到達する．この複数の到来波を受信機への到達時間ごとに分解し合成するのがRAKE受信機である．本論文では通信路の状態に合わせて適応的に合成係数を変化させるRAKE受信機を提案し，周波数利用効率を約４倍改善することを示した．

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