说明：  用NS2仿真802.11b WLAN信道。指出现有NS2代码中的错误，给出SNR、BER的计算公式和代码实现。
(Simulate 802.11b Channel within NS2 This document describes how to simulate one 802.11b channel in NS2. It focuses on how to simulate wireless transmission error due to bad channel quality. That means BER need to be considered to determine whether one frame is transmitted correctly. To get BER, SNR need to be calculated. The following sections describe current simulation of transmission error in NS2, the methods to calculate SNR and BER, and how to incorporate these methods into NS to achieve our aim--- to simulate 802.11b channels as exactly as possible.)