Space-time Chase decoding

An Improved Bound on the List Error Probability and List Distance Properties

“…It follows from (5) and (9) that the list error probability can be fully described in terms of the properties of the Gram matrix Γ. For binary codes, this matrix determines the so-called minimum Hamming list distance of the code [27], d HLmin , which plays the same role for list decoding as the minimum distance for maximumlikelihood decoding.…”

“…More generally, the turbo receiver principle is applicable to many communication systems that can be represented as concatenated coding schemes, where the inner code is, for example, realized by a modulator followed by the intersymbol interference (ISI) channel, or by a spacetime code for multiple-antenna transmission. List-based inner SISO detectors that form the symbol reliability estimates from a list of signal vectors were proposed, e.g., in [9] for MIMO transmission and in [10] for ISI equalization.…”

Efficient soft demodulation of MIMO QPSK via semidefinite relaxation

“…The first observation in the development of the proposed demodulator is that the expression in (8) suggests that for the purposes of soft demodulation, one could consider generating a sequence of bit vectors with properties similar to those generated by the formal randomization process by making the approximation that each element ofx is independent, and generating each element ofx via a scalar (antipodal) Bernoulli trial. This approach avoids the cost of computing V T u in each instance of the formal randomization procedure.…”

“…It consists of an SDR demodulator (which is invoked only in the first iteration), and a randomized soft demodulator. The randomized soft demodulator takes two inputs: (i) a vector L containing the mean values in (8) …”

“…1. However, the computational cost of the maximum a posteriori probability (MAP) soft demodulator increases exponentially with the number of bits transmitted per channel use, and hence there has been considerable interest in the design of approximate (quasi-MAP) soft demodulation schemes with lower complexity; e.g., [1][2][3][4][5][6][7][8].…”