Competitive analysis of on-line randomized call control in cellular networks

In this paper we address an important communication issue arising in cellular (mobile) networks that utilize Frequency Division Multiplexing (FDM) technology. In such networks, many users within the same geographical region can communicate simultaneously with other users of the network using distinct frequencies. The spectrum of the available frequencies is limited; thus, efficient solutions to the call control problem are essential. The objective of the call control problem is, given a spectrum of available frequencies and users that wish to communicate, to maximize the number of users that communicate without signal interference. Using competitive analysis, we study the performance of algorithm p-RANDOM; an intuitive on-line randomized call control algorithm proposed previously for cellular networks. We give upper and lower bounds of its competitive ratio against oblivious adversaries as a function of the parameter p. Optimizing the upper bound function, we prove that there exists a 2.651-competitive randomized call control algorithm. In this way, we significantly improve the best known upper bound on the competitiveness of on-line randomized call control which was 2.934