Beyond Integer-Forcing Receiver for Lattice-Code Based Multi-User MIMO System

This letter studies a lattice-code based multi-user MIMO system. In the uplink, K single-antenna users encode their messages with the same q-ary linear code mapped to q -PAM, belonging to the ensemble of lattice codes. The NR-antenna receiver attempts to compute K independent streams of integer-combinations (ICBs) of the users' messages. To this end, we put forth a new interference-whitening (IW) based ICB detection method, which reduces the loss of the linear filtering operation in existing integer-forcing (IF). The soft detection outputs are forwarded to K channel-code decoders to recover the messages. For practical configurations with moderate-to-large K , the proposed ICB detection exhibits an enlarged achievable mutual information and considerably improved FER performance, over existing IF.