Performance of Spatial Phase Coding (SPC) in Broadband OFDM Systems

In this paper a spatial phase coding (SPC) scheme is investigated for its application in OFDM systems. With SPC the phase relation of the signals between multiple transmit antennas is modified such that the probability of constructive superposition of the signals at the receiver antenna is increased. The principle is based on selective phase flipping. The promising feature of this scheme is that only the superimposed channel has to be estimated at the receiver and not all channels from the different transmit antennas. Moreover, it requires a very small amount of feedback information for pre-coding compared to existing solutions. The performance of SPC is compared to that of spatial diversity and pre-coding schemes like phase flip diversity (PFD), cyclic delay diversity (CDD) and maximum ratio transmission (MRT) for typical indoor as well as outdoor environments.