Efficient implementation of OVSF code generator for UMTS systems

In this paper, we propose a multi-stage OVSF code generator using single code index. The performances of the conventional methods such as logic gates, counter or LUT are evaluated in terms of complexity, speed and power dissipation according to various spreading factors used in UMTS systems. The results are applied to our multi-stage design in order to implement the most efficient code generator. The proposed structure that is synthesized in Samsung 0.35 mum CMOS library decreases the power consumption up to 26.5%. It needs 203 more gates compared to the counter based generator which is the most efficient among the conventional methods, which can be ignored in terms of the whole chip area.