DocumentCode :
586261
Title :
Ergodic Capacity of Multi-User MIMO Systems Using Pilot-Based Channel Estimation, Quantized Feedback and Outdated Feedback as Well as User Selection
Author :
Jin, Fan ; Hanzo, Lajos
Author_Institution :
Sch. of ECS, Univ. of Southampton, Southampton, UK
fYear :
2012
fDate :
3-6 Sept. 2012
Firstpage :
1
Lastpage :
5
Abstract :
We derive the ergodic channel capacity of a closed-loop MIMO broadcast system under both random user selection (RUS) and semi-orthogonal user selection (SUS) principles, when considering the effects of channel estimation errors, channel state information (CSI) quantization errors and CSI feedback-delay. We intend to answer the question of "How many simultaneous users should be active in a time slot in order to achieve the maximum sum-rate in a MIMO broadcast system?". It is shown that we should refrain from supporting full-rank transmissions due to the excess inter-user interference caused by imperfect CSI at both the receiver and transmitter under RUS. By contrast, full-rank transmissions may be feasible under the SUS principle. An approximate ergodic capacity equation is also derived for RUS, and then an adaptive-rank transmission strategy is derived, which is capable of maximizing the achievable ergodic capacity.
Keywords :
MIMO communication; broadcast channels; channel capacity; channel estimation; closed loop systems; feedback; interference (signal); multiuser channels; radio receivers; radio transmitters; random processes; CSI feedback-delay; CSI quantization errors; RUS principles; SUS principles; adaptive-rank transmission strategy; channel estimation errors; channel state information quantization errors; closed-loop MIMO broadcast system; ergodic capacity equation; ergodic channel capacity; full-rank transmissions; interuser interference; multiuser MIMO systems; outdated feedback; pilot-based channel estimation; quantized feedback; radio receiver; radio transmitter; random user selection; semiorthogonal user selection priciple; Approximation methods; Channel estimation; Delay; MIMO; Quantization; Signal to noise ratio; Vectors;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Vehicular Technology Conference (VTC Fall), 2012 IEEE
Conference_Location :
Quebec City, QC
ISSN :
1090-3038
Print_ISBN :
978-1-4673-1880-8
Electronic_ISBN :
1090-3038
Type :
conf
DOI :
10.1109/VTCFall.2012.6399232
Filename :
6399232
Link To Document :
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