Bi-directional optical CDMA-based fiber-radio ring networks

One fiber radio network based on optical codedivision multiple access is proposed. This scheme has ring topology with self-healing ability and allows bi-directional communications between control base station and the remote base stations (RBSs). Two code families are proposed for this scheme and the corresponding correlation properties can be used for interference elimination. As compared to the conventional codes used in the spectral-amplitude-coding scheme, they not only have better carrier-to-noise ratio (CNR) in the decoder, but also alleviate the influence of splitting loss for the broadcasting of RBSs´ signal. In addition, the encoding/decoding devices in the RBSs have smaller sizes than that of conventional codes. Thus the complexity and cost of RBSs are reduced and a large number of RBSs is allowed to deploy for future low power radio mobile communications.