Improving the Performance of the Zero-Forcing Multiuser MISO Downlink Precoder Through User Grouping
2016 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 15, no 2, 811-826 p.Article in journal (Refereed) PublishedText
We consider the multiple input single output (MISO) Gaussian broadcast channel with N-t antennas at the base station (BS) and N-u single-antenna users in the downlink. We propose a novel user grouping precoder which improves the sum rate performance of the zero-forcing (ZF) precoder specially when the channel is ill-conditioned. The proposed precoder partitions all the users into small groups of equal size. Downlink beamforming is then done in such a way that, at each users receiver, the interference from the signal intended for users not in its group is nulled out. Intragroup interference still remains, and is cancelled through successive interference presubtraction at the BS using dirty paper coding (DPC). The proposed user grouping method is different from user selection, since it is a method for precoding of information to the selected (scheduled) users, and not for selecting which users are to be scheduled. The proposed precoder is a generalization of two special cases, one where each group has only one user (ZF precoder) and another where all users are in a single group (ZF-DP precoder). A larger group size helps improve the sum rate performance but at the cost of greater complexity. The proposed generalization, therefore, allows for tradeoff between performance and complexity.
Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC , 2016. Vol. 15, no 2, 811-826 p.
MIMO broadcast channel; precoding; low complexity; user grouping; dirty paper coding; zero-forcing
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:liu:diva-126260DOI: 10.1109/TWC.2015.2478878ISI: 000370949600001OAI: oai:DiVA.org:liu-126260DiVA: diva2:913434
Funding Agencies|EMR funding from the Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Government of India; Swedish Research Council; ELLIIT2016-03-212016-03-212016-08-31