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ABSTRACT: In this paper, we consider spatial-division multiple-access (SDMA) systems with one base station with multiple antennae and a number of single antenna mobiles under noisy limited CSIT feedback. We propose a robust noisy limited feedback design for SDMA systems. Furthermore, we show that despite the noisy feedback, the average system goodput scales as O(n<sub>T</sub>(1-¿)/n<sub>T</sub>-1(C<sub>fb</sub> -log<sub>2</sub>(N<sub>n</sub>))) and O(n<sub>T</sub>·log<sub>2</sub> P) in the interference limited regime (C<sub>fb</sub> < (n<sub>T</sub> - 1) log<sub>2</sub> P + log<sub>2</sub> N<sub>n</sub>) and noise-limited regime respectively.
IEEE Transactions on Wireless Communications 05/2010; · 2.59 Impact Factor
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ABSTRACT: In this paper, we shall focus on the design and asymptotic performance analysis of joint source channel coding (JSCC) for MIMO channels with limited Channel State Information (CSI) feedback. We consider rate adaptation, spatial power adaptation as well as precoder adaptation. We find that the optimal distortion exponent (achieved with perfect CSIT) can be realized using only spatial power adaptation and precoder adaptation with sufficiently large feedback rate. We also compare the average distortion of the limited feedback JSCC system using fixed bandwidth expansion scheme and dynamic bandwidth expansion scheme. We show that dynamic bandwidth expansion is more effective to reduce the limited feedback JSCC performance especially at large average bandwidth expansion.
IEEE Transactions on Wireless Communications 07/2009; · 2.59 Impact Factor
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ABSTRACT: In this paper, we propose two robust limited feedback designs for multiple-input multiple-output (MIMO) adaptation. The first scheme, namely, the combined design jointly optimizes the adaptation, CSIT (channel state information at the transmitter) feedback as well as index assignment strategies. The second scheme, namely, the decoupled design , focuses on the index assignment problem given an error-free limited feedback design. Simulation results show that the proposed framework has significant capacity gain compared to the naive design (designed assuming there is no feedback error). Furthermore, for large number of feedback bits C <sub>fb</sub>, we show that under two-nearest constellation feedback channel assumption, the MIMO capacity loss (due to noisy feedback) of the proposed robust design scales like O ( Pe 2<sup>-[(</sup> C <sub>fb</sub>)/( t +1)]) for some positive integer t . Hence, the penalty due to noisy limited feedback in the proposed robust design approaches zero as C <sub>fb</sub> increases.
IEEE Transactions on Information Theory 05/2009; · 3.01 Impact Factor
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ABSTRACT: In this paper, we shall focus on a robust joint rate, power and precoder design for MIMO slow fading channels with noisy limited feedback. To take into consideration of the potential packet errors, we optimize the system goodput (b/s/Hz successfully delivered to the receiver) with respect to a general model of limited feedback error. We show that the codebook design that maximizes the system goodput can be converted to an equivalent "maximin" problem. Numerical results show that the proposed framework can achieve significant goodput gain comparing to various naive designs (designed for error- free limited feedback). Simulation results demonstrated the importance of taking the potential CSIT errors into the limited feedback design for robust performance.
IEEE Transactions on Wireless Communications 07/2008; · 2.59 Impact Factor
