Integer-Forcing Linear Receivers: A New Low-Complexity MIMO Architecture

We propose a new framework for MIMO decoding based on a recently developed technique for reliably conveying linear equations over wireless channels. Each transmit antenna sends an independent data stream using the same linear code. As a result, any integer combination of the codewords is itself a codeword. Each receive antenna observes a random complex-valued combination of the codewords according to the fading coefficients. We use a linear pre-processing step at the receiver to transform the effective channel into a (full-rank) integer matrix. A single stream decoder is then used to recover integer combinations of the codewords. These equations of codewords are then translated into equations of the transmitted data streams over a finite field which can be easily solved for the original data. We examine the performance of our scheme in terms of the probability of outage and show that significant gains are possible over standard linear architectures for both i.i.d. and correlated Rayleigh fading.