由于无线链路易受到外界干扰，导致数据传输的误码率较高，从而使得数据包成功传输概率降低。而误码所造成的丢包会使无线链路上的TCP传输自动降速，从而对正常的TCP数据传输造成较大影响。针对上述问题，本文在802.11协议的MAC层提出了一种新的校验机制，采用动态分块校验的方法对数据包进行验证，并采用新的方法来计算重传次数。实验表明，本校验机制可以有效提高数据包成功传输概率，进而改善了无线链路上的TCP传输性能，同时保证了多个数据流传输的公平性和数据的正确性。

The problem of high BER (bit error rate) usually plagues the wireless communication, especially for the TCP connections. As TCP cannot distinguish wireless loss from congestion loss, thus its performance over high BER wireless networks suffers from unnecessary congestion window decreases. To improve the performance of TCP in such a scenario, a Dynamic-Segment method for MAC 802.11 (DS-MAC) is proposed. Simulation experiments show that the proposed method is fair, and can result in higher TCP throughput along with higher bandwidth utilization efficiency.