An Algorithm for Restraining the OVSF Codes Shortage in HSDPA

To improve the system performance, DSCH and HS-DSCH channels are used in the existing releases of the mobile systems for bursty Internet traffic services. OVSF codes are assigned during the data transfer time of a session in these channels. Here, through the use of a multiplexer / scheduler, a queue and a buffer, we have introduced a Traffic Model Scheduler (TMS) in layer 2 / RLC of HSDPA to reduce the OVSF code usage in HS-DSCH and could save them. Here, we have assigned OVSF codes to traffic services only during the packet transfer time. We have analyzed the TMS module analytically and compared it with two simulation modes. Simulation proved that by a reasonable blocking rate we are able to save the OVSF codes enough.