Channel prediction for mitigating feedback link issues in transmit antenna selection systems

Transmit antenna selection (TAS) in multiple-input-multiple output (MIMO) has several advantages, particularly in hardware-costly transmit schemes such as those requiring linearisation. However TAS requires either channel knowledge, or receiver knowledge at the transmitter, typically achieved using data transmission in the reverse direction. This process involves a reverse channel bandwidth cost, but also implies a delay between the channel sampling and the switching. To reduce reverse channel costs, the bandwidth may be rate constrained. Thus both delay and feedback rate will limit the performance of a TAS system. To mitigate against these performance limitations, in this paper a prediction scheme is applied to systems employing transmit antenna selection with maximal ratio combining.