Transceiver design for MIMO wireless systems incorporating hybrid ARQ

IEEE Communications Magazine (Impact Factor: 3.66). 02/2009; DOI: 10.1109/MCOM.2009.4752674
Source: IEEE Xplore

ABSTRACT Hybrid ARQ, an extension of ARQ that incorporates forward error correction coding, is a retransmission scheme employed in current communications systems. The use of HARQ can contribute to efficient utilization of the available resources and the provision of reliable services in latest-generation systems. This article focuses on wireless systems using HARQ with emphasis on the multiple-input multiple-output paradigm. MIMO-HARQ offers new opportunities because of the additional degrees of freedom introduced by the multiple antennas at the transmitter and receiver. The architecture of MIMO transceivers that are based on bit-interleaved coded modulation and employ HARQ is described. Additionally, receiver implementations are presented and compared in terms of complexity, memory requirements, and performance.

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    ABSTRACT: Truncated Type-I and Type-II HARQ schemes are compared, in terms of throughput, when incremental decode and forward relaying is used. The comparison is based on the outage analysis of both schemes. Two different scenarios are considered: ad-hoc relaying, where all users are at ground level, and infra-structured relaying, where the relay and the destination antennas are at a higher height than the user. Moreover, we also consider the effect of rate adaptation. Results show that Type-II (incremental redundancy) only significantly outperforms Type-I schemes (selection and Chase combining) in the case of ad-hoc relaying without rate adaptation, and in the low SNR region.
    Proceedings of the 73rd IEEE Vehicular Technology Conference, VTC Spring 2011, 15-18 May 2011, Budapest, Hungary; 01/2011
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    Proceedings of the 73rd IEEE Vehicular Technology Conference, VTC Spring 2011, 15-18 May 2011, Budapest, Hungary; 01/2011
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    ABSTRACT: In next generation wireless networks, high data rates under strict quality of service (QoS) constraints call for fl exible radio interfaces capable of adapting their configuration on the fly to the time-varying operating environment. Motivated by this need, this paper first derives a simple link performance pred iction model for bit interleaved coded orthogonal frequency division multiplexing (BIC-OFDM) systems using incremental redundancy (IR) hybrid automatic repeat request (HARQ) mechanisms. Then, an adaptive HARQ strategy is formulated whose aim is maximizing the goodput (GP) metric, i.e., the number of error-free information bits delivered to the user by unit of time, over the coding rate, the bit distribution and an on-off power allocation across the active subchannels. Simulation results corroborate the GP performance gains of the proposed approach compared with non-adaptive trans- missions, while keeping the computational complexity at affordable levels.

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