A new approach to layered space-time coding and signal processing

The information-theoretic capacity of multiple antenna systems was shown to be significantly higher than that of single antenna systems In Rayleigh-fa ding channels. In an attempt to realize this capacity, Foschini proposed th e layered space-time architecture. This scheme was argued to asymptotically achieve a lower bound on the capacity. Another line of work has focused on the design of channel codes that exploit the spatial diversity provided by multiple transmit antennas [2], [3]. In this paper, we take a fresh look at the problem of designing multiple-in put-multiple-output (MIMO) wireless systems. First, we develop a generalize d framework for the design of layered space-time systems. Then, we present a novel layered architecture that combines efficient algebraic code design with iterative signal processing techniques. This novel layered system is r eferred to as the threaded space-time (TST) architecture. The TST architect ure provides more flexibility in the tradeoff between power efficiency, ban dwidth efficiency, and receiver complexity. It also allows for exploiting t he temporal diversity provided by time-varying fading channels. Simulation results are provided for the various techniques that demonstrate the superi ority of the proposed TST architecture over both the diagonal layered space -time architecture in [1] and the recently proposed multilayering approach [4].