IEEE Transaction on Wireless Communications, vol. 7, no. 11, pp. 4051-4057, Nov. 2008.
Precoding with block diagonalization is an attractive technique for approaching the sum capacity in multiuser multiple input multiple output (MIMO) broadcast channels. Unfortunately, this method requires either global channel state information at every receiver or an additional training phase, which demands additional control overhead and additional system planning. In this paper we propose a new multiuser MIMO algorithm that combines block diagonalization with vector perturbation. The proposed algorithm avoids the second training phase, reduces each user's receiver complexity thanks to pre-equalization with vector perturbation at the transmitter, and has comparable diversity performance to block diagonalization with maximum likelihood decoding algorithm. A bound on the achievable sum rate for the proposed technique is derived and used to show that it approaches the achievable sum rate of block diagonalization with water-filling. Numerical simulations show that the proposed technique provides better bit error rate and diversity performance than BD with a zero-forcing receiver as well as BD with zero-forcing precoding.
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