El Ayach, OmarLozano Solsona, AngelHeath, R. W., Jr.2015-04-132015-04-132012El Ayach O, Lozano A, Heath RW. On the overhead of interference alignment: training, feedback, and cooperation. IEEE Transactions on Wireless Communications. 2012 Nov; 11(11): 4192-203. DOI 10.1109/TWC.2012.0924121205881536-1276http://hdl.handle.net/10230/23403Interference alignment (IA) is a cooperative transmission strategy that, under some conditions,/nachieves the interference channel’s maximum number of degrees of freedom. Realizing IA gains,/nhowever, is contingent upon providing transmitters with sufficiently accurate channel knowledge. In/nthis paper, we study the performance of IA in multiple-input multiple-output systems where channel/nknowledge is acquired through training and analog feedback.We design the training and feedback system/nto maximize IA’s effective sum-rate: a non-asymptotic performance metric that accounts for estimation/nerror, training and feedback overhead, and channel selectivity. We characterize effective sum-rate with/noverhead in relation to various parameters such as signal-to-noise ratio, Doppler spread, and feedback/nchannel quality. A main insight from our analysis is that, by properly designing the CSI acquisition/nprocess, IA can provide good sum-rate performance in a very wide range of fading scenarios. Another/nobservation from our work is that such overhead-aware analysis can help solve a number of practical/nnetwork design problems. To demonstrate the concept of overhead-aware network design, we consider/nthe example problem of finding the optimal number of cooperative IA users based on signal power and/nmobility.application/pdfeng© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works./nThe final published article can be found at http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6319338info:eu-repo/semantics/articlehttp://dx.doi.org/10.1109/TWC.2012.092412120588MIMOAnalog feedbackChannel estimationChannel state information (CSI)Interference alignmentInterference cancellationInterference channelsMultiple access interferenceinfo:eu-repo/semantics/openAccess