Efficient Soft-Output Demodulation of MIMO QPSK via Semidefinite Relaxation

Asymmetric Turbo Code for Coded-Cooperative Wireless Communication Based on Matched Interleaver with Channel Estimation and Multi-Receive Antennas at the Destination

“…Soft-demodulation for MIMO is proposed in [32]. The soft-demodulator with multi-receive antennas and joint iterative SISO decoder are connected in serial concatenation.…”

MIMO soft demodulation via semidefinite relaxation: Efficient dual-scaling implementation and performance analysis

“…The single-SDR soft demodulator [12], [13] is a listbased demodulator in which the list is generated using a randomization procedure. The probabilities involved in that randomization procedure are obtained from the solution of a semidefinite program (SDP) (solved once per channel use) and the prior probabilities from the previous iteration of the decoder.…”

“…In the second and subsequent iterations the list generator should incorporate the (prior) information from the previous iteration of the decoder, since the interleaved encoded bits are assumed to be locally independent, we can simply modify the distribution of the independent random number generators according to [12], [13] as…”

“…At each iteration, the generated list is enriched by adding all the bit vectors that are one bit flip away from a member of the list [12], [13].…”

“…Recently, it was shown that for systems with QPSK signalling, the randomization procedure that is inherent to the semidefinite relaxation approach to MIMO hard demodulation (e.g., [11]) can be used to generate high-quality lists at modest average computational cost and with a cost distribution that is concentrated around the average [12]. Preliminary work on extending the approaches in [12] to 16-QAM signalling has indicated considerable potential [13], [14]. In this paper, we take several steps towards realizing that potential.…”