The performance of the ZF-BF system will be degraded unless the channel status information at the transmitter (CSIT) is perfect. In order to provide CSIT to the transmitter, each receiver must feed back CSI estimated at the receiver. Caire, Jindal, Kobayashi, Ravinderan has compared the performance differences of digital feedback and analog feedback schemes[1]:

\Delta R^{AF} \leq \log \left( 1 + \frac{1}{\beta} \right)

\Delta R^{DF} \leq \log \left( 1 + \frac{ \frac{P}{N_0} }
{\left( 1 + \frac{P}{N_0}\right)^\beta }

where P/N_0 is the SNR and \beta is the symbols per antenna.


  1. G. Caire, N. Jindal, M. Kobayashi, and N. Ravindran, Multiuser MIMO Achievable Rates with Downlink Training and Channel State Feedback, Submitted to IEEE Trans. Information Theory, Nov. 2007. (Revised May 2009)

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.