Improvement of spectral efficiency in optical wireless OFDM system using intensity modulation

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06346
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Communication/Network engineering
• Research Institution: Shizuoka University
• Principal Investigator: ohuchi kouji 静岡大学, 工学部, 准教授 (50313937)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 光無線通信 / 直交周波数分割多重 / 強度変調 / 周波数利用効率

Outline of Final Research Achievements

The objective of this study is to accomplish an OFDM system that achieves both high spectral efficiency and power saving transmission in optical wireless communication using intensity modulation and direct detection. In the conventional ACO-OFDM system, power saving transmission is achieved using only odd numbered subcarriers. However, there is a problem that even numbered subcarriers can not be used. In this study, even-numbered subcarriers are made available by multiplexing multiple ACO-OFDM signals with different fundamental frequencies, and the amount of transmission information is increased. Furthermore, the interference signal caused by signal multiplexing is reduced by a canceller. As a result, it is clarified that we can double the spectral efficiency compared to the conventional ACO-OFDM system.

Free Research Field

情報通信工学

Academic Significance and Societal Importance of the Research Achievements

電波無線通信でよく使われている無線通信技術の一つに直交周波数分割多重(OFDM)方式がある．このOFDM方式を光無線通信に応用する場合，従来技術では，周波数利用効率と省電力性を両立することは困難だった．それに対して，本研究では，新しい方法で信号を多重化し，伝送する方法を示しており，伝送情報量の増加を図っている．その結果，周波数利用効率と省電力性の点でバランスのとれた光無線OFDM方式を実現している．したがって，本研究の成果は，光無線通信におけるOFDM方式の活用を一層促進させることに寄与するものと考えられる．