FIBEROPTIC SUBCARRIER MULTIPLEXED CDMA LOCAL-AREA NETWORKS FOR SUBBAND IMAGE TRANSMISSION

This paper investigates the application of subcarrier multiplexed code -division multiple-access (CDMA) techniques to image transmission over fiber-optic local-area networks (LAN's), In the hybrid scheme, CDMA i s used to suppress the interference caused by the laser nonlinearity i n the subcarrier multiplexing (SCM) fiber-optic communication systems, Likewise, the SCM scheme is able to increase the channel data rate of CDMA systems, This hybrid system combines the advantages of both sche mes and is particularly well suited to subband coding that divides the image information into multiple parallel data streams using an analys is filter bank, each of which is transmitted via a unique subcarrier-c ode pair, where the spreading code and subcarrier frequency correspond to the image and one of its subbands, respectively, This hybrid schem e also allows more than one image to be transmitted and be accessed si multaneously at the same channel bandwidth, in which each image is ass igned a particular spreading code added to its digital data modulating the subcarrier. After transmission, each received signal is independe ntly recovered at a high-Q surface acoustic wave (SAW) receiver with t he matching subcarrier-code pair, Other concurrent signals are rejecte d by the SAW, Then, all the recovered subbands are reassembled by a sy nthesis filter bank into a close reproduction to the original image, I n this paper, the image quality of subband image transmission via CDMA /SCM fiber-optic channels is evaluated and examined.