A new look at hybrid Aloha: an analytical approach

Hybrid Aloha is a new medium access control protocol which has been designed to improve the performance of wireless networks. This is by allowing collision free channel estimation that transmits data of multiple users simultaneously. In this paper, a general form of throughput model for hybrid Aloha system in term of the specified number of users with particular number of pilot sub-slots is proposed. Using the existing equation of hybrid Aloha throughput, fundamental principles of counting from discrete mathematics and probability theory, a recursive equation for hybrid Aloha throughput is extracted, then a simple equation in term of number of users and pilot sub-slots is described. In addition, an analysis of hybrid Aloha throughput under an infinite number of users is explained. Based on this analysis the maximum value of normalized throughput of hybrid Aloha is 1eτ, where the τ is pilot sub-slot size. Furthermore, a comparison between analytical and simulation results of hybrid Aloha for different number of users and arrival rate is presented.