Wireless-OCDMA Encoding Technologies Research And Realization

Wireless Optical Code Division Multiple Access (W-OCDMA) is one of the technologies for the future free space optical communications, all optical access networks and local area networks. OCDMA technologies possess the characteristics of fitting for asynchronous random access, many simultaneous users sharing the same channel. It not only keeps combating interference, security, soft capacity and simply network protocol, but also makes use of the huge bandwidth of fiber. But the OCDMA is interference limited system, so for the W-OCDMA system, it's important to construct the address codes with large capacity and good relativity.This dissertation is around the study of freedom degrees of optical encoding mechanism, and cany out the construction of W-OCDMA codes with large capacity. We have constructed new two-dimensional codes for the W-OCDMA, and multilength two-dimensional codes MWOOC and MW RS for the multirate communication.We have designed the encoder and decoder for the W-OCDMA system, and carried on the research and simulation to the factors, which influence the performance of encoder and decoder. Considering the ideal free space channel and the Additive White Gaussian Noise channel, we investigated the channel capacity, discussed the frequency efficiency, and proved the feasibility of multiple freedom degrees encoding from the angle of information theory. We built up the fiber OCDMA experiment system and demonstrated the encoding and decoding procedure. The paper contains six chapters as follows.1 Summarizing of the fundamental, the development, the key technologies, and the status of W-OCDMA, bring forward the research direction of codeword in W-OCDMA.2 We investigated the address codes of W-OCDMA system, discussed the different single freedom degree encoding and multiple freedom degrees combined encoding mechanism with the help of Shannon theorem. Constructed the two dimensional MPC/OOC fit for the synchronization...