Yazarel, Y. K.Aktaş, Defne2016-02-082016-02-082007-08http://hdl.handle.net/11693/26918Date of Conference: 22-24 Aug. 2007Conference name: 2007 IEEE Pacific Rim Conference on Communications, Computers and Signal ProcessingIn this paper we consider the problem of finding the optimum beamforming vectors for the downlink of a multiuser system, where there are individual signal to interference plus noise ratio (SINR) targets for each user. Majority of the previous work on this problem assumed a total power constraint on the base stations. However, since each transmit antenna is limited by the amount of power it can transmit due to the limited linear region of the power amplifliers, a more realistic constraint is to place a limit on the per antenna power. In a recent work, Yu and Lan proposed an iterative algorithm for computing the optimum beamforming vectors minimizing the power margin over all antennas under individual SINR and per antenna power constraints. However, from a system designer point of view, it may be more desirable to minimize the total transmit power rather than minimizing the power margin, especially when the system is not symmetric. Reformulating the transmitter optimization problem to minimize the total transmit power subject to individual SINR constraints on the users and per antenna power constraints on the base stations, the algorithm proposed by Yu and Lan is modified. Performance of the modified algorithm is compared with existing methods for various cellular array scenarios. ©2007 IEEE.EnglishAntenna accessoriesBase stationsBeamformingBoolean functionsComputer systemsElectric power utilizationIterative methodsLight polarizationSignal interferenceSignal processingSignal to noise ratioVectorsDownlink (DL)Downlink beam-formingIndividual (PSS 544-7)Iterative algorithmsLinear regionsMulti user systemsPacific RimPer-antenna power constraintsPower marginsSignal-to-Interference plus Noise-Ratio (SINR)System designersTotal powerTotal transmit powerTransmit antennasTransmitter optimizationAntennasConference Paper10.1109/PACRIM.2007.4313264