Impact of TCP flow control on the radio resource management of WCDMA networks

The present paper highlights the performance of the transport control protocol over WCDMA networks. The TCP flow control adjusts the transmission rate to the network and receiver´s capacity. Due to this protocol self-adaptation to the transmission conditions of the links involved in the TCP connection, the protocol performance can not be disconnected from the underlying network. In WCDMA networks, the RRM assigns the radio resources to the UE in the cell, which directly impacts the TCP throughput performance. The results show that the allocation of high bit rate dedicated channels to small file downloads (such as Web pages) produce poor channelization code efficiency compared to allocating low bit rate channels. Under certain conditions, for large file downloads (such as ftp) the code efficiency and throughput performance improve significantly due to the protocol nature to fully utilize the bottleneck capacity. This protocol performance suggests a radio resource allocation strategy for DCH channels, which increases the bit rate stepwise as the file transmission evolves starting from a low bit rate.