The Study Of Wireless Optical Code Division Multiple Access

Wireless optical code division multiple access (WOCDMA) is a communication mode which introduces the code-division multiple access (CDMA) technology into wireless optical communication system. Besides providing asynchronous communications access, WOCDMA system has many advantages, such as high capacity, security against interception, suppression of narrow band disturbances, capability in forming variable bit rate networks and multi-rate networks. It implies a great challenge for the development of future communication networks, especially all optical networks.There are three problems in WOCDMA technology. One problem is the capacity is too little. The second problem is which scheme selected from among the channel codes. The third problem is about multi-user detection.We discuss the spread spectrum code in WOCDMA system. Beginning with the characteristic of spread spectrum in WOCDMA system, we devise some kinds of code with a good performance, also calculate the correlation and the BER of the code. We achieve the correlation plot of the code we have noticed, also, we imitate the result on the computer with the correlation coefficient and the capacity of the system. In this paper we design the new encoders/decoders in WOCDMA system. We discuss the reason of this device, describe the structure and the function of the system. We also analyse this system in its performance. We investigate and research thoroughly channel of wireless optical CDMA. As far as indoors, outdoors and free space conditions are concened, we establish respectively two-type channel models. Channel coding is always aimed at channel. We imitate the result on the computer with the performance of the channel codes. Decorrelating detection is employed for the two channel models..