Joint Source and Channel Coding for MIMO Systems: Is it Better to be Robust or Quick?

• Published in: IEEE transactions on information theory Vol. 54; no. 4; pp. 1393 - 1405
• Main Authors: Holliday, T., Goldsmith, A.J., Poor, H.V.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Applied sciences; Automatic repeat request; Automatic repeat request (ARQ); Channel coding; Channels; Codes; Coding, codes; Concatenated codes; Data encryption; Data transmission; Delay; Design optimization; Distortion; diversity-multiplexing-delay tradeoff; Dynamic programming; Exact sciences and technology; Formulations; Functional analysis; Information processing; Information theory; Information, signal and communications theory; joint source-channel coding; Mathematical analysis; MIMO; multiple- input multiple-output (MIMO) channels; Multiplexing; Optimization; Radiocommunications; Robustness; Signal and communications theory; Telecommunications; Telecommunications and information theory; Transmitting antennas; Performance evaluation; Multiplexing; MIMO system; joint source-channel coding; Vector quantization; Automatic repeat request (ARQ); Diversity; Information rate; Space time; Delay system; Joint source channel coding; Convex programming; Information transmission; Optimization; diversity-multiplexing-delay tradeoff; Analytical method; Delay time; Dynamic programming; Automatic repeat request; multiple- input multiple-output (MIMO) channels; Antenna; Transmission error; Signal to noise ratio
• ISSN: 0018-9448; 1557-9654
• DOI: 10.1109/TIT.2008.917725

A framework is developed for optimizing the tradeoff between diversity, multiplexing, and delay in multiple-input multiple-output (MIMO) systems to minimize end-to-end distortion. The goal is to find the optimal balance between the increased data rate provided by antenna multiplexing, the reduction in transmission errors provided by antenna diversity and automatic repeat request (ARQ), and the delay introduced by ARQ. First, closed-form analytical results are developed to minimize end-to-end distortion of a vector quantizer concatenated with a space-time MIMO channel code in the high SNR regime. The minimization determines the optimal point on the diversity-multiplexing tradeoff curve. For large but finite SNR this optimal point is found via convex optimization, which is illustrated with an example of a practical joint source-channel code design. It is then shown that for MIMO systems with ARQ retransmission, sources without a delay constraint have distortion minimized by maximizing the ARQ window size. This results in a new multiplexing-diversity tradeoff region enhanced by ARQ. However, under a source delay constraint the problem formulation changes to account for delay distortion associated with random message arrival and random ARQ completion times. In this case, the simplifications associated with a high SNR assumption break down, and a dynamic programming formulation is required to capture the channel diversity-multiplexing tradeoff as well as the random arrival and retransmission dynamics. Results based on this formulation show that a delay-sensitive system obtains significant performance gains by adapting its operating point on the diversity-multiplexing-delay region to system dynamics.