Pseudo-Random Scrambling for Quasi-Static MIMO Channels

This paper investigates a blind MIMO precoding technique and benchmarks its performance in a realistic environment. The use of pseudo-random unitary precoding matrices (called "channel scrambling" in this paper) has been proposed to combat quasi- static channels with low diversity, both for the purpose of diversity coding and spatial multiplexing. In this paper we analyse the problem of poor soft output when the channel matrix is almost singular and how channel scrambling can help.The benefits of channel scrambling are quantified in a ray-traced channel and it is shown that substantial gains can be obtained from this simple technique.