Integrating new calls and performance improvement in OVSF based CDMA Networks

In code division multiple access (CDMA), orthogonal variable spreading factor (OVSF) codes are used to allocate vacant codes when new calls arrive. In this paper, integration is done for allocation of OVSF codes when a quantized or non-quantized call arrives, and further, the voice calls and data calls are treated differently as former are delay sensitive and later can be stored in buffer. Voice calls are assigned a busy or vacant code when a call arrives. The rate of data calls can increase or decrease according to the availability of free capacity in code tree or according to type of traffic load. Single code and multi code schemes are proposed which minimize the internal fragmentation of busy codes by utilizing their wastage capacity. In addition, the external fragmentation is also reduced. The vacant code is assigned when busy code wastage capacity is insufficient to handle a call. Simulation results prove dominance of our scheme over other novel schemes.