MIMO ARQ systems with multi-level feedback
ISIT'09 Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 1
On the average rate performance of hybrid-ARQ in quasi-static fading channels
IEEE Transactions on Communications
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Performance of hybrid-ARQ in block-fading channels: a fixed outage probability analysis
IEEE Transactions on Communications
Turbo packet combining for broadband space-time BICM hybrid-ARQ systems with co-channel interference
IEEE Transactions on Wireless Communications
Coded modulation with mismatched CSIT over MIMO block-fading channels
IEEE Transactions on Information Theory
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In this paper, we consider an automatic-repeat-request (ARQ) retransmission protocol signaling over a block-fading multiple-input-multiple-output (MIMO) channel. Unlike previous work, we allow for multiple fading blocks within each transmission (ARQ round), and we constrain the transmitter to fixed rate codes constructed over complex signal constellations. In particular, we examine the general case of average input-power-constrained con stellations with a fixed signaling alphabet of finite cardinality. This scenario is a suitable model for practical wireless communications systems employing orthogonal frequency division multiplexing (OFDM) techniques over a MIMO ARQ channel. Two cases of fading dynamics are considered, namely, short-term static fading where channel fading gains change randomly for each ARQ round, and long-term static fading where channel fading gains remain constant over all ARQ rounds pertaining to a given message. As our main result, we prove that for the block-fading MIMO ARQ channel with a fixed signaling alphabet satisfying a short-term power constraint, the optimal signal-to-noise ratio (SNR) exponent is given by a modified Singleton bound, relating all the system parameters. To demonstrate the practical significance of the theoretical analysis, we present numerical results showing that practical Singleton-bound-achieving maximum distance separable codes achieve the optimal SNR exponent.