Some Analysis of a Cross-Layer Design for a Wireless TCP Network

The Transport Control Protocol (TCP) throughput can be decreased in wireless networks. One of the approaches presented in the literature to overcome this problem is Cross-Layer Design. In this paper we have computed the TCP throughput in a wireless network as a function of the wireless channel Bit Error Rate (BER), the frame size and the retransmission protocol used at the Data Link Layer (BILL). We have proved that TCP throughput can be increased if the segment size in the Transport Layer is adjusted according to the BER and the DLL protocol. Based on our results, we have proposed a Cross-Layer scheme in which these two parameters are informed to TCP so its segment size (which affects the frame size) can be adjusted in order to achieve optimal throughput.