A new CDMA scheme for multicasting using information classes

A new method of code allocation in code division multiple access is proposed that is particularly efficient in meeting multicasting needs, based on the concept of partitioned information `classes´ (CDMA-IC). Transmitters choose spreading codes based on the types of messages they are transmitting, and receivers listen to codes corresponding to the types of messages they are interested in. The performance of this approach can exceed that of both the traditional receiver-directed codes or broadcast codes in environments where there are several multicast groups (in which a given message is of interest to more than one node). Performance is further enhanced when receivers can simultaneously attempt to correlate multiple spreading codes. In a previous paper the authors (see IEEE Military Communications Conference (MILCOM), p.556-560, Boston, October 1993) demonstrated the superiority of CDMA-IC over receiver-directed CDMA and broadcasting, using simulation of some preliminary concepts of the scheme. In this paper, we describe a broader theoretical framework considering such attributes as priorities, relevance and `value´ of the messages, in which the CDMA-IC scheme scheme could be tailored for different scenarios and could be parameterized appropriately