Reduced Feedback SDMA Based on Subspace Packings
2009 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 8, no 3, 1329-1339 p.Article in journal (Refereed) Published
Herein, we treat Space Division Multiple Access (SDMA) based on partial channel state information and limited feedback. We propose a novel framework utilizing subspace packings, where beamforming, feedback, and scheduling are integrated. Advantages of the proposed framework are that the fed back supportable rates are based on the post-scheduling SINR and that the feedback implicitly contains information about the spatial compatibility of the users. The feasibility region of packings of different dimensions is indicated by the allocation outage probability which is derived. Grassmannian subspace packings, DFT-based packings, and non-orthogonal Grassmannian packings are formulated and studied as candidates. Numerical simulations show better performance for the proposed scheme compared to conventional channel quantization at the receiver with zero-forcing transmission in i.i.d. Rayleigh fading. Finally, we propose and evaluate a beam-graph method to further reduce the feedback load, that can be used in the context of tracking quantized beamformers.
Place, publisher, year, edition, pages
IEEE , 2009. Vol. 8, no 3, 1329-1339 p.
Multi-user MIMO, SDMA, feedback, limited feedback, side information, fading channels, performance, systems, capacity, design
Telecommunications Communication Systems
IdentifiersURN: urn:nbn:se:kth:diva-18251DOI: 10.1109/twc.2009.071245ISI: 000264293200041ScopusID: 2-s2.0-62949098636OAI: oai:DiVA.org:kth-18251DiVA: diva2:336297
QC 201005252010-08-052010-08-052012-05-29Bibliographically approved