Throughput efficient block-spreading CDMA: sequence design and performance comparison

In this paper we propose a new multiple user architecture for broadband wireless communications based on code division multiple access, denoted block CDMA (B-CDMA). The B-CDMA transmitter spreads the data on a block basis and a single cyclic prefix is used at the end of each spread block. We investigate the orthogonality of spreading sequences for B-CDMA, for an uplink broadband transmission and we design sequences that minimize the power of multiuser access interference. Equalization of the received signal is performed through an iterative block decision feedback equalizer (IBDFE). The B-CDMA system is compared to existing block spreading schemes in terms of achievable throughput for a wireless broadband uplink transmission.