Precoder Design With Incomplete Feedback for Joint Transmission
Artikel i vetenskaplig tidskrift, 2016

A centralized coordinated multipoint downlink joint transmission in a frequency division duplex system requires channel state information (CSI) to be fed back from the cell-edge users to their serving BS, and aggregated at the central coordination node for precoding, so that interference can be mitigated. The control signals comprising of CSI and the precoding weights can easily overwhelm the backhaul resources. Relative thresholding has been proposed to alleviate the burden; however, this is at the cost of reduction in throughput. In this paper, we propose utilizing the long term channel statistics comprising of pathloss and shadow fading in the precoder design to model the statistical interference for the unknown CSI. In this regard, a successive second order cone programming (SSOCP) based precoder for maximizing the weighted sum rate is proposed. The accuracy of the solution obtained is bounded with the branch and bound technique. An alternative optimization framework via weighted mean square error minimization is also derived. Both these approaches provide an efficient solution close to the optimal, and also achieve efficient backhauling, in a sense that the precoding weights are generated only for the active links. For comparison, a stochastic approach based on particle swarm optimization is also considered.


limited backhauling/feedback

branch and bound

weighted sum rate maximization





Tilak Rajesh Lakshmana

Chalmers, Signaler och system, Kommunikation, Antenner och Optiska Nätverk

Antti Tölli

Oulun Yliopisto

Rahul Devassy

Chalmers, Signaler och system, Kommunikation, Antenner och Optiska Nätverk

Tommy Svensson

Chalmers, Signaler och system, Kommunikation, Antenner och Optiska Nätverk

IEEE Transactions on Wireless Communications

15361276 (ISSN) 15582248 (eISSN)

Vol. 15 3 1923-1936 7315049

Mobile and wireless communications Enablers for Twenty-twenty (2020) Information Society (METIS)

Europeiska kommissionen (EU) (EC/FP7/317669), 2012-11-01 -- 2015-04-30.


Informations- och kommunikationsteknik





C3SE (Chalmers Centre for Computational Science and Engineering)



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