In‐house wireless optical digital SSMA

Abstract

With the recent development of the office automation, portable in‐house terminals for data communication have attracted attention. For this purpose, wireless transmission by optical link is considered promising, since it does not require the installation of signal lines. The past discussions and experiments, however, considered only the one‐to‐one or one‐to‐many communications, but many‐to‐many, i.e., multiple connections were not considered. This paper aims at the application of the spread‐spectrum system to the wireless optical communication link to realize the multiple connections, and derives the basic theoretical expressions for the receiver characteristics. More precisely, the modulation scheme is selected taking the restriction into consideration, which is inherent to the inhouse wireless optical link. Then, the receiver error rate and the multiple connection characteristics of the proposed modulation scheme have been theoretically derived, providing the basis for the system design. Finally, a qualitative discussion is made on the construction and operation of the synchronous system for the proposed modulation scheme.