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arXiv · 0903.4582

On the Achievable Diversity-Multiplexing Tradeoff in MIMO Fading Channels with Imperfect CSIT

Xiao Juan Zhang·Yi Gong
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Abstract

In this paper, we analyze the fundamental tradeoff of diversity and multiplexing in multi-input multi-output (MIMO) channels with imperfect channel state information at the transmitter (CSIT). We show that with imperfect CSIT, a higher diversity gain as well as a more efficient diversity-multiplexing tradeoff (DMT) can be achieved. In the case of multi-input single-output (MISO)/single-input multi-output (SIMO) channels with K transmit/receive antennas, one can achieve a diversity gain of d(r)=K(1-r+Kα) at spatial multiplexing gain r, where αis the CSIT quality defined in this paper. For general MIMO channels with M (M>1) transmit and N (N>1) receive antennas, we show that depending on the value of α, different DMT can be derived and the value of αhas a great impact on the achievable diversity, especially at high multiplexing gains. Specifically, when αis above a certain threshold, one can achieve a diversity gain of d(r)=MN(1+MNα)-(M+N-1)r; otherwise, the achievable DMT is much lower and can be described as a collection of discontinuous line segments depending on M, N, r and α. Our analysis reveals that imperfect CSIT significantly improves the achievable diversity gain while enjoying high spatial multiplexing gains.

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Xiao Juan Zhang, Yi Gong. 2009-08-16. On the Achievable Diversity-Multiplexing Tradeoff in MIMO Fading Channels with Imperfect CSIT. https://arxiv.org/abs/0903.4582

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