EURASIP Journal on Applied Signal Processing 
Volume 2004 (2004), Issue 5, Pages 772-782
doi:10.1155/S1110865704311042

Multiple ARQ Processes for MIMO Systems

Haitao Zheng, Angel Lozano, and Mohamed Haleem

Wireless Research Laboratory, Lucent Technologies, 791 Holmdel-Keyport Road, Holmdel 07733, NJ, USA

Received 4 December 2002; Revised 19 August 2003

Abstract

We propose a new automatic repeat request (ARQ) scheme for MIMO systems with multiple transmit and receive antennas. The substreams emitted from various transmit antennas encounter distinct propagation channels and thus have different error statistics. When per-antenna encoders are used, separating ARQ processes among the substreams results in a throughput improvement. Moreover, it facilitates the interference cancellation in certain MIMO techniques. Quantitative results from UMTS simulations demonstrate that the proposed multiple ARQ structure yields more than 30% gain in link throughput.