Sum discrete-rate maximization with rate and power control in layered space-time coding

This paper generalizes the information-theoretic optimality of minimum mean square error successive interference cancellation in layered space-time coding with rate and power control. Based on this derivation, a new concept relying on partial feedback is introduced, whose core idea is to exploit an additional degree of freedom relative to the partitioning of transmit antennas. Taking into account this additional degree of freedom, together with power control and decoding order, allows the reduction of the quantization noise induced by the use of finite discrete-rate sets at the transmitter. However, the simultaneous optimization of all those degrees of freedom proves to be computationally intensive and would result in a tremendous feedback load. Practical algorithms are thus proposed to achieve this optimization with a reasonable complexity and a limited amount of feedback. Monte-Carlo simulations show that those algorithms perform close to the theoretical limits.