Transport channel switching for interactive TCP/IP traffic in WCDMA

In a WCDMA system, the feature transport channel switching assigns to each best-effort user a transport channel that is appropriate for the user´s bit-rate requirements and radio conditions. In this paper, we compare fixed rate channel allocation with several channel switching schemes, where the user is switched between transport channel rates based on the user´s current code power consumption. Results show that with channel switching the capacity and/or the user throughput are increased compared to fixed transport channel allocation. The best channel switching scheme from system capacity perspective is a scheme that gradually increases the channel bit-rate. Due to variations in the radio environment there is always a risk that a connection is lost. Therefore, there must exist a mechanism for down-switching the bit-rate of the transport channel to retain the coverage.