In this paper, we simulate throughput of mobile ad hoc networks with IEEE 802.11 over fading channels with impulse noise, and consider two cases: 1) the system with ARF algorithm and 2) the system with fixed rate. The simulated results show that the system with ARF algorithm has the similar throughput of 11 Mbps when the channel is AWGN without impulse noise. However, the system with ARF algorithm has the like throughput of 1 Mbps when the channel is Rayleigh without or with impulse noise. In addition, we consider that velocity ranges of stations impact on throughputs. The simulation results show that the throughput is worse than others when the velocity range is larger.