METHOD AND SYSTEM FOR SUM-RATE OF BROADCAST CHANNELS WITH OUTDATED 1-BIT FEEDBACK

摘要

A single-input single-output (SISO) downlink channel with K users is analyzed in the presence of Rayleigh flat fading. A limited channel state information (CSI) feedback scheme is included, where only an outdated 1-bit feedback per user is available at the base station for each fading block. A closed-form expression for the achievable ergodic sum-rate of the 1-bit feedback scheme is presented for any number of users, as a function of the fading temporal correlation coefficient, the threshold of the 1-bit CSI quantizer and the SNR. The sum-rate scales with increasing number of users as log logK, which is the same scaling law achieved by the optimal non-delayed full CSI feedback scheme.