Efficient and Robust Multiuser Decision-Delay Selection Scheme in the MIMO TDMA System

J.-K. Hwang and R.-L. Chung (Taiwan)

Keywords

– Multiuser detection, finite-length MIMO DFE, multiuser decision delays, power imbalance, TDMA system.

Abstract

We investigate the finite-length Multiuser MIMO DFE (MU-MIMO-DFE) Receiver for the uplink TDMA system, with the same decision delay and with multiple different decision delays in the power imbalance situation. It is shown that the decision delays, especially for DFE with fewer filter taps, must be carefully selected, or else the performance loss for the weaker users would be very significant. We propose two schemes for adaptively selecting decision delays on the burst-by-burst case, instead of only using an identical and common decision delay for all uplink users. The first scheme is optimized by the MMSE criterion, and the other is based on the user power ratio. Both schemes are demonstrated to be able to benefit from the power imbalance situation, without the near-far effect when using a fixed and common delay for all users. Moreover, it is also found that the power-ratio based scheme can almost achieve the performance of the optimal one while the complexity load can reduce significantly.

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