Relativity-based access strategy for frequency hopping system

In this study, two relativity-based access strategies are proposed for frequency hopping system with cognitive ability (C-FH). Sensing module is added in the receiver to perform real-time measurement of channel states. The first access strategy is studied in consideration of partial relative FH pattern. The spectrum band is divided into several groups and each C-FH user can only jump over the channel group authorised by the active user. In the second access strategy, the C-FH user will adaptively choose an active user as the scheduler to apply for access. The application users may be rejected because of lack of resources or accepted to access the available channels in order of arranged sequence. The chosen scheduler will accept applications according to number of available channels and the spectrum resource will be shared in condition of being temporally correlated. With relativity-based strategies, FH patterns of users have the minimum Hamming correlation, even to zero. Markov chains are built to model the access processes. The performance analysis and the simulation results show that the relativity-based access strategy brings lower collision probability, higher bandwidth utilisation and higher normalised average throughput.