Among the methods that have been proposed for a multiple-input multiple-output (MIMO) receiver, the V-BLAST algorithm provides a good compromise between transmission rate, achievable diversity, and decoding complexity. In this letter, we derive a new adaptive V-BLAST-type equalization scheme for fast time-varying, flat-fading MIMO channels. The proposed equalizer stems from the Cholesky factorization of the MIMO system's output data autocorrelation matrix, and the equalizer filters are updated in time using numerically robust unitary Givens rotations. The new square-root algorithm exhibits identical performance to a recently proposed V-BLAST adaptive algorithm, offering at the same time noticeable reduction in computational complexity. Moreover, as expected due to its square-root form and verified by simulations, the algorithm exhibits particularly favorable numerical behavior.
Bibliographical noteFunding Information:
Manuscript received October 25, 2005; revised December 6, 2005. This work was supported in part by C.T.I.-R&D. V. Kekatos is a scholar of the Bodossaki Foundation. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Brian Sadler.
- Adaptive equalization
- Multiple-input multiple-output (MIMO)
- Time-varying channels