Carrier frequency offset-spread spectrum multiple access (CFO-SSMA) method

A novel spread spectrum multiple access method employing only a single PN code is proposed. This new method, named “CFO-SSMA (carrier frequency offset-spread spectrum multiple access)”, utilizes a single PN code commonly assigned to all users with different carrier frequencies. The amount of the frequency offset between carriers is determined by the information rate, which is very small as compared with the bandwidth of the spread spectrum signal. CFO-SSMA employs a receiver using a surface acoustic wave (SAW) matched filter, which has an advantage of rapid signal acquisition over the conventional receiver, but has a disadvantage of difficulty to change the PN code pattern. CFO-SSMA defeats this disadvantage, because there is no need to change the matched filer in accordance with the channel to be recovered. The concept and basic performance of CFO-SSMA is discussed in this paper. The optimum bandwidth of the receive filter as well as the BER performance of CFO-SSMA are also shown