Semi-adaptive beamforming for OFDM based hybrid terrestrial-satellite mobile system

Khan, A. H., Imran, M. A. and Evans, B. G. (2012) Semi-adaptive beamforming for OFDM based hybrid terrestrial-satellite mobile system. IEEE Transactions on Wireless Communications, 11(10), pp. 3424-3433. (doi:10.1109/TWC.2012.083112.110130)

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Abstract

Adaptive interference mitigation requires significant resources due to recursive processing. Specific to satellite systems, interference mitigation by employing adaptive beamforming at the gateway or at the satellite both have associated problems. While ground based beamforming reduces the satellite payload complexity, it results in added feeder link bandwidth requirements, higher gateway complexity and suffers from feeder link channel degradations. On the other hand, employing adaptive beamforming onboard the satellite gives more flexibility in case of variation in traffic dynamics and also for changing of beam patterns. However, these advantages come at the cost of additional complexity at the satellite. In pursuit of retaining the benefits of onboard beamforming and to reduce the complexity associated with adaptive processing, we here propose a novel semi-adaptive beamformer for a Hybrid Terrestrial-Satellite Mobile System. The proposed algorithm is a dual form of beamforming that enables adaptive and non-adaptive processing to coexist via a robust gradient based switching mechanism. We present a detailed complexity analysis of the proposed algorithm and derive bounds associated with its power requirements. In the scenarios studied, results show that the proposed algorithm consumes up to 98% less filter computing power as compared to full-adaptive case without compromising on system performance.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Imran, Professor Muhammad
Authors: Khan, A. H., Imran, M. A., and Evans, B. G.
College/School:College of Science and Engineering > School of Engineering
Journal Name:IEEE Transactions on Wireless Communications
Publisher:Institute of Electrical and Electronics Engineers
ISSN:1536-1276
ISSN (Online):1558-2248
Published Online:05 September 2012
Copyright Holders:Copyright © 2012 IEEE
First Published:First published in IEEE Transactions on Wireless Communications 11(10): 3424-3433
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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