Efficient code assignment strategy for UMTS

This paper presents an integrated solution for code management and assignment problems. We propose a new architecture for code management, and based on this new architecture, a new code assignment strategy, referred to as 'crowded-group first strategy'. Our system architecture and code assignment strategy represent significant improvements in the time complexity and in the complexity of the storage operation. Moreover, the code blocking probability of the crowded-group first strategy can be as good as that of the crowded-first strategy. In order to systematically analyze the performance of the code assignment strategy, we implement a simulator to analyze the code selection behavior of each strategy. Moreover, in the numerical analyses, we propose a new performance metric, named 'weighted code blocking', in order to precisely measure the performance obtained by different strategies. From the simulation results, we show that our strategy efficiently utilizes the OVSF codes with the low computation overhead.