Frequency domain hybrid–ARQ chase combining for broadband MIMO communication with co-channel interference

We address the issue of efficient iterative (turbo) packet combining for broadband space-time coded transmission with hybrid-automatic repeat request (ARQ) over co-channel interference (CCI)-limited multiple-input-multiple-output (MIMO) channel. We introduce a new frequency domain turbo combining scheme where multiple transmissions are combined at the signal level using soft minimum mean square error (MMSE) processing. The proposed technique allows to recursively combine received signal packets in the frequency domain, and does not require to explicitly store signals and channel frequency responses (CFR)s corresponding to multiple ARQ rounds. We analyze both the computational complexity and memory requirements of the proposed scheme and show that are quite insensitive to the ARQ delay, i.e., the maximum number of ARQ rounds. Block error rate (BLER) performance is investigated to examine the gains offered by the new technique.