A Layered-Steered Space-Time Coded system with optimal power allocation

Layered Steered Space-Time Codes (LSSTC) is a recently proposed multiple-input multiple-output (MIMO) system that combines the benefits of vertical Bell Labs space-time (VBLAST) scheme, space-time block codes (STBC) and beamforming. We suggest a new downlink scheme employing LSSTC with optimal power allocation, by assuming that the user feeds the BS with the average SNR per VBLAST layer through the uplink feedback channel. The motivation behind proposing such a system is to enhance the error performance by assigning power to the layers in an optimum manner. We refer to the system proposed as the optimum power allocation LSSTC (OPA-LSSTC). We will show that the OPA-LSSTC can provide about a 3 dB gain compared to the equal power allocation case.