Power-controlled feedback and training for two-way MIMO channels

Most communication systems use some form of feedback, often related to channel state information. The common models used in analyses either assume perfect channel state information at the receiver and/or noiseless state feedback links. However, in practical systems, neither is the channel estimate known perfectly at the receiver and nor is the feedback link perfect. In this paper, we study the achievable diversity multiplexing tradeoff using i.i.d. Gaussian codebooks, considering the errors in training the receiver and the errors in the feedback link for FDD systems, where the forward and the feedback are independent MIMO channels. Our key result is that the maximum diversity order with onebit of feedback information is identical to systems with more feedback bits. Thus, asymptotically in SNR, more than one bit of feedback does not improve the system performance at constant rates. Furthermore, the one-bit diversity-multiplexing performance is identical to the system which has perfect c...

• Type: Journal
• Year: 2010
• Where: TIT
• Authors: Vaneet Aggarwal, Ashutosh Sabharwal
• Keywords: Channel State Information, Education, Feedback, Feedback Links, TIT 2010