Phase-Sweep Transmit Diversity (PSTD) for Shared Data Channels: A critical analysis

In this paper we propose a promising multi-antenna scheme for shared data channel users, which provides the benefits of beamforming without the requirement of additional channel state information at the transmitter. This scheme, called PSTD (Phase Swept Transmit Diversity) was originally proposed for dedicated voice users. We evaluate the benefits of PSTD for both closely-spaced ($lambda/2$) and widely-spaced antenna arrays (e.g. $10 lambda$), and compare these to pre-existing schemes, such as STD and single antenna transmission (1Tx). We analyze stationary and low mobility users, because they have the highest potential benefits, as well as users from mixed mobility populations. We find both closely-spaced and diversity antenna array PSTD schemes to perform better than the other schemes, with the closely spaced antennas producing consistently higher throughputs.