Proposal of Switching Speed Reduction Method Using Chaotic Spreading Sequence in Direct Optical Switching CDMA Radio-on-Fiber Network and Its Experimental Investigation

Takeshi HIGASHINO
Katsutoshi TSUKAMOTO
Shozo KOMAKI

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C    No.7    pp.1475-1482
Publication Date: 2005/07/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.7.1475
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Technologies of Microwave and Millimeter-Wave Devices Focusing on Miniaturization and Advancement in Performance with Their Applications)
Category: Communication Systems
Keyword: 
radio on fiber,  bandpass sampling,  code division multiple access,  chaotic spreading sequence,  M-sequence,  

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Summary: 
The direct optical switching CDMA radio-on-fiber network is proposed as multiplexing method for radio base stations in microcell/picocell technologies. In this system, aliasing distortions degrade the received signal quality and decreases the number of connectable radio base stations (RBSs) when the encoding rate becomes lower than the twice of bandwidth of RF signal. This paper proposes the optical switching speed reduction method and clarifies that the chaotic spreading sequences can suppress the aliasing distortion without additional processing at the receiver even if the encoding rate becomes lower than the RF signal bandwidth. The effect in switching speed reduction is theoretically investigated and the effect in aliasing distortions suppression is experimentally investigated by using the proposed method.