Utilizing the synchrony among base stations for better performance of channel assignment algorithms

A radio spectrum is a shared, limited, and expensive resource in cellular networks. A network allocates a channel from the spectrum to provide connectivity to a user. With the ever increasing number of users, it is a challenge and a business opportunity to support as many simultaneous users as possible. Hence, designing better channel assignment algorithms remains a topic of continued research interest. In this paper, we propose a new technique to reduce the failure rates of a class of dynamic channel assignment algorithms, namely, channel assignment without measurement (CAWM). The technique assumes that all the base stations in a network are synchronized. By synchronized base stations, we mean the time slots on all the carriers in all the cells have the same start times. This assumption allows a base station to acquire one channel when there is a need, rather than acquire all the channels on a carrier when there is a need for just one channel. This is expected to lead to better availability of channels in the entire network when there is a need, because channels are not held up without any use. By using this assumption, we have redesigned four dynamic channel assignment algorithms, namely, the Nanda-Goodman strategy, the Geometric strategy, the Bidirectional Channel Locking (BDCL) strategy, and the Two-Step Dynamic Priority (TSDP) strategy. Simulation results confirm our initial expectation. There is significant improvement in the failure rates of the Nanda-Goodman and the TSDP strategies, whereas the Geometric and the BDCL strategies show significant improvements up to certain call arrival rates.