Open Access

Approaching the MIMO Capacity with a Low-Rate Feedback Channel in V-BLAST

  • Seong Taek Chung1Email author,
  • Angel Lozano2,
  • Howard C Huang2,
  • Arak Sutivong3 and
  • John M Cioffi1
EURASIP Journal on Advances in Signal Processing20042004:816702

Received: 8 December 2002

Published: 23 May 2004


This paper presents an extension of the vertical Bell Laboratories Layered Space-Time (V-BLAST) architecture in which the closed-loop multiple-input multiple-output (MIMO) capacity can be approached with conventional scalar coding, optimum successive decoding (OSD), and independent rate assignments for each transmit antenna. This theoretical framework is used as a basis for the proposed algorithms whereby rate and power information for each transmit antenna is acquired via a low-rate feedback channel. We propose the successive quantization with power control (SQPC) and successive rate and power quantization (SRPQ) algorithms. In SQPC, rate quantization is performed with continuous power control. This performs better than simply quantizing the rates without power control. A more practical implementation of SQPC is SRPQ, in which both rate and power levels are quantized. The performance loss due to power quantization is insignificant when 4–5 bits are used per antenna. Both SQPC and SRPQ show an average total rate close to the closed-loop MIMO capacity if a capacity-approaching scalar code is used per antenna.


adaptive antennasBLASTinterference cancellationMIMO systemsspace-time processingdiscrete bit loading

Authors’ Affiliations

STAR Laboratory, Stanford University
Wireless Research Laboratory, Lucent Technologies
Information Systems Laboratory, Stanford University


© Chung et al. 2004