Papers - Adachi, Koichi

Data Gathering Method with High Accuracy of Environment Recognition Using Mathematical Optimization in Packet-Level Index Modulation

Ryuji MIYAMOTO, Osamu TAKYU, Hiroshi FUJIWARA, Koichi ADACHI, Mai OHTA, Takeo FUJII

IEICE Transactions on Communications (Institute of Electrical and Electronics Engineers (IEEE))  E106.B ( 12 ) 1337 - 1349 2023.12

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

• Access to Document (DOI)

Transmission Control for Highly Efficiency Data Gathering in Packet-Level Index Modulation

Ryuji Miyamoto, Osamu Takyu, Hiroshi Fujiwara, Koichi Adachi, Mai Ohta, Takeo Fujii

Int. Conf. on Emerging Technol. for Commun. (ICETC'24)    1 - 5 2023.12

Research paper (international conference proceedings), Accepted

Characterization of Discrimination of Number of Signal Collision Sensors Using Spectral Fluctuation Caused by Frequency Offset in Physical Wireless Parameter Conversion Sensor Networks

Toshi Ito, Osamu Takyu, Mai Ohta, Takeo Fujii, Koichi Adachi

The 26th Int. Symp. on Wireless Personal Multimedia Commun. (WPMC 2023)    1 - 5 2023.11

Research paper (international conference proceedings), Accepted

Packet-Level Index Modulation under Duty Cycle Constraints

Ryogo Ohta, Shinichiro Kakuda, Takeo Fujii, Osamu Takyu, Mai Ohta, Koichi Adachi

The 26th Int. Symp. on Wireless Personal Multimedia Commun. (WPMC 2023)    1 - 5 2023.11

Research paper (international conference proceedings), Accepted

Interference Cancellation for Coexistence of LoRaWAN with Wireless Power Transfer

Ryota Kumada, Koichi Adachi

IEEE Internet Things J. (Institute of Electrical and Electronics Engineers (IEEE))  10 ( 15 ) 13109 - 13122 2023.08

Research paper (scientific journal), Accepted

• Access to Document (DOI)

Dynamic Path Planning for QoS Improvement in Multiple Automated Guided Vehicles

Takumi Tanagi, Koichi Adachi

2023 VTS Asia Pacific Wireless Commun. Symp. (APWCS)    1 - 5 2023.08

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

Three Level Recognition Based on the Average of the Phase Differences in Physical Wireless Parameter Conversion Sensor Networks and Its Effect to Localization with RSSI

Toshi Ito, Masafumi Oda, Osamu Takyu, Mai Ohta, Takeo Fujii, Koichi Adachi

Sensors (MDPI AG)  23 ( 6 ) 3308 - 3308 2023.03

Research paper (scientific journal), Accepted

　View Summary

In recent years, there have been increased demands for aggregating sensor information from several sensors owing to the spread of the Internet of Things (IoT). However, packet communication, which is a conventional multiple-access technology, is hindered by packet collisions owing to simultaneous access by sensors and waiting time to avoid packet collisions; this increases the aggregation time. The physical wireless parameter conversion sensor network (PhyC-SN) method, which transmits sensor information corresponding to the carrier wave frequency, facilitates the bulk collection of sensor information, thereby reducing the communication time and achieving a high aggregation success rate. However, when more than one sensor transmits the same frequency simultaneously, the estimation accuracy of the number of accessed sensors deteriorates significantly because of multipath fading. Thus, this study focuses on the phase fluctuation of the received signal caused by the frequency offset inherent to the sensor terminals. Consequently, a new feature for detecting collisions is proposed, which is a case in which two or more sensors transmit simultaneously. Furthermore, a method to identify the existence of 0, 1, 2, or more sensors is established. In addition, we demonstrate the effectiveness of PhyC-SNs in estimating the location of radio transmission sources by utilizing three patterns of 0, 1, and 2 or more transmitting sensors.

• Access to Document (DOI)

Resource Allocation for Periodic Traffic in Wireless Sensor Network

Aoto Kaburaki, Koichi Adachi, Osamu Takyu, Mai Ohta, Takeo Fujii

IEEE WCNC International Workshop on Smart Spectrum (IWSS 2023)  2023.03

Research paper (international conference proceedings), Accepted

Position Estimation of Radio Source Based on Fingerprinting With Physical Wireless Parameter Conversion Sensor Networks

Masafumi Oda, Osamu Takyu, Mai Ohta, Takeo Fujii, and Koichi Adachi

IEEE Access (IEEE)  11   12843 - 12857 2023.02

Research paper (scientific journal), Accepted

• Access to Document (DOI)

Aiming in Harsh Environments: A New Framework for Flexible and Adaptive Resource Management

Jiaqi Zou, Rui Liu, Chenwei Wang, Yuanhao Cui, Zixuan Zou, Songlin Sun, Koichi Adachi

IEEE Network (IEEE)  36 ( 4 ) 70 - 77 2022.10

Research paper (scientific journal), Accepted

• Access to Document (DOI)

Simple Clock Drift Estimation & Compensation for Packet-Level Index Modulation and its Implementation in LoRaWAN

Kohei Tsurumi, Aoto Kaburaki, Koichi Adachi, Osamu Takyu, Takeo Fujii

IEEE Internet of Things Journal (IEEE)  9 ( 16 ) 15089 - 15099 2022.08

Research paper (scientific journal), Accepted

• Access to Document (DOI)

High-Sensitivity Detection Method for Signals in PhyC-SN

Toshi Ito, Osamu Takyu, Mai Ohta, Takeo Fujii, Koichi Adachi

ICUFN 2022  2022.07

Research paper (international conference proceedings), Accepted

Performance Evaluation of Highly Efficient Information Collection Methods by Trend Analysis of Sensor Information Using Pre-Learning

Ryuji Miyamoto, Osamu Takyu, Hiroshi Fujiwara, Koichi Adachi, Mai Ohta, Takeo Fujii

ICUFN 2022  2022.07

Research paper (international conference proceedings), Accepted

Estimation Based on Chirp Modulation for Desired and Interference Power and Channel Occupancy Ratio in LoRa

Osamu Takyu, Gaku Kobayashi, Koichi Adachi, Mai Ohta, Takeo Fujii

Sensors ({MDPI} {AG})  22 ( 11 ) 4140 2022.05

Research paper (scientific journal), Accepted

• Access to Document (DOI)

Flexible Index Mapping Scheme for Packet-Level Index Modulation

Kosuke Suzuki, Koichi Adachi, Mai Ohta, Osamu Takyu, Takeo Fujii

IEEE Wireless Communications Letters (IEEE)  11 ( 4 ) 703 - 706 2022.04

Research paper (scientific journal), Accepted,  ISSN  2162-2337

　View Summary

Long range wide area network (LoRaWAN) attracts attention due to its ability to realize massive machine-type communication (MTC); however, the throughput is low due to its narrow-band transmission and chirp spread spectrum. Packet-level index modulation (PLIM) increases the throughput by utilizing a data packet’s frequency channel and transmission timing as an information-bearing index. This letter proposes a flexible index mapping scheme to fully utilize the available frequency channels and transmission timings to increase the number of bits transmitted by an index and avoid packet collision. Numerical results show that the proposed scheme improves the throughput and significantly reduces the required memory size of end nodes.

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Estimation Accuracy to Channel Occupancy Ratio and Signal Power under Co-Channel Interference in LoRa

Gaku Kobayashi, Osamu Takyu, Koichi Adachi, Mai Ohta, Takeo Fujii

2021 Int. Conf. on Emerging Technologies for Commun. (ICETC2021)    1 - 1 2021.12

Research paper (international conference proceedings), Accepted

Achievable Rate Enhancement based on Multi-packet Indexing in Packet-Level Index Modulation

Riku Yamabe, Mikihiko Nishiara, Osamu Takyu, Koichi Adachi

IEEE Access (IEEE)  9   154938 - 154946 2021.11

Research paper (scientific journal), Accepted

• Access to Document (DOI)

Channel Allocation for LoRaWAN Considering Intra-System and Inter-System Interferences

S. Kakuda, Y. Yamazaki, K. Katagiri, T. Fujii, O. Takyu, M. Ohta, K. Adachi

The 2021 IEEE 94th Vehicular Technology Conference (VTC'21-fall)    1 - 5 2021.09

Research paper (international conference proceedings), Accepted

Proposal of Interference Power Occupancy Estimation Method Using Chirp Demodulation

G. Kobayashi, O. Takyu, K. Adachi, M. Ohta, T. Fujii

The 12th International Conference on Ubiquitous and Future Networks (ICUFN 2021)    1 - 5 2021.08

Research paper (international conference proceedings), Accepted

Autonomous Decentralized Traffic Control Using Q-learning in LPWAN

A. Kaburaki, K. Adachi, O. Takyu, M. Ohta, T. Fujii

IEEE Access (IEEE)  9   93651 - 93661 2021.06

Research paper (scientific journal), Accepted

• Access to Document (DOI)