**5. Simulation results**

0 5 10 15 20 25 30 35 40

0 5 10 15 20 25 30 35 40

SNR [dB]

MMSE-SUI 1 MMSE-SUI 3 MMSE-SUI 5 AWGN only

MMSE-SUI 1 MMSE-SUI 3 MMSE-SUI 5 AWGN only

SNR [dB]

10-4

**Figure 11.** BER Performance comparison (16QAM, *N*=256).

10-4

**Figure 12.** BER Performance comparison (16QAM, *N*=512).

10-3

10-2

BER

10-1

100

10-3

10-2

BER

10-1

100

50 Selected Topics in WiMAX

The performance of proposed WiMAX is evaluated using computer simulation. In this study, the channel is assumed to be known perfectly at the receiver. The simulated system employs an OFDM signal with *N = 256* subcarriers, among which *192* data carriers (*QPSK, 16QAM or 64QAM* signal mapping), *8* pilots, the others are nulls, guard interval *Tg = (1/4)Tb*, where *Tb* is the useful symbol time, and sampling frequency=9.12 *MHz*. For simplicity, uncoded OFDM will be employed. When applying the compander/expander, we must take into account some system constraints: Neither the pilots nor the guard intervals are allowed to be modified, for reasons of standard compliance.
