Shielding TCP from Wireless Link Errors: Retransmission Effort and Fragmentation

A known problem for TCP connections over wireless links is that errors in the wireless channel interfere with the TCP protocol even for minor packet loss. In the first part of this paper we evaluate how the data rate reduction depends on the channel delay. For comparatively short delays in the order of 100 ms, the decrease of the throughout is noticeable but not dramatic. This indicates that the problem is not severe if the communication partners are located in the same WLAN or interact over a fast Internet connection. A significant throughput reduction arises in the case of a large network delay. Simulation results for the uplink transmission are presented as part of an overall strategy in which all improvements are made by optimizing the mobile end device only, an approach which allows performance improvements without any protocol modifications.