Fig.7.11 shows the effect on capacity of CSI at transmitter.Notice that,while the capacity with CSI at the receiver only never exceeds that of the AWGN channel,no such ineq ver We observe that,unless the SNR is very low,CSI at transmitter increases capacity very little Shannon bound(Rayleigh with CSITR) 3 Shannon bound(Rayleigh with CSIR) Shannon bound (AWGN) 2.5 10 SNR(dB) (a) 19 Fig.7.11 shows the effect on capacity of CSI at transmitter. Notice that, while the capacity with CSI at the receiver only never exceeds that of the AWGN channel, no such inequality holds for the capacity with CSI at transmitter and receiver. We observe that, unless the SNR is very low, CSI at transmitter increases capacity very little. -10 -5 0 5 10 15 20 0 0.5 1 1.5 2 2.5 3 3.5 SNR (dB) Capacity (bits/symbol) Shannon bound (Rayleigh with CSITR) Shannon bound (Rayleigh with CSIR) Shannon bound (AWGN) (a)