Conference Proceeding

Transmit beamforming with cooperative base stations

Dept. of Electr. & Electron. Eng., Melbourne Univ., Vic.
10/2005; DOI:10.1109/ISIT.2005.1523579 pp.1431 - 1435 In proceeding of: Information Theory, 2005. ISIT 2005. Proceedings. International Symposium on
Source: IEEE Xplore

ABSTRACT We consider a cellular network where base stations can cooperate to determine the signals to be transmitted on the downlink. In such a scenario, it would be possible to use "macroscopic" transmit beamforming to improve system performance. The downlink beamformer of interest is generalised from some transmit beamformers that have been shown to meet various optimality criteria in the literature. The particular downlink beamformer structure enables us to recast our downlink beamforming problem as a virtual LMMSE estimation problem. Based on this virtual set up, we exploit the structure of the channel and develop distributed beamforming algorithms using local message passing between neighbouring base stations. Two algorithms are outlined, both of which are based on the Kalman smoothing framework. The first algorithm is a forward-backward algorithm that produces optimal performance, but it has the disadvantage of a delay that grows linearly with array size. The second algorithm, which is a limited extent algorithm, solves the delay problem by using only local information

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Keywords

algorithms
 
array size
 
base stations
 
beamforming algorithms
 
cellular network
 
downlink beamformer
 
downlink beamforming problem
 
first algorithm
 
forward-backward algorithm
 
grows linearly
 
Kalman smoothing framework
 
limited extent algorithm
 
particular downlink beamformer structure enables
 
produces optimal performance
 
scenario
 
second algorithm
 
transmit beamformers
 
transmit beamforming
 
various optimality criteria
 
virtual LMMSE estimation problem