Slow Frequency Hopping Multiple Access for Digital Cellular Radiotelephone

Abstract

A theoretical analysis of slow frequency hopping is presented together with a comparison to other multiple access techniques. The propagation and modulation models are described and the multiple access protocols are analyzed with an information theory approach. It is explained why the speed of variation of some random variables is important for protocol evaluation. A definition of capacity is given and is first applied to simple systems. Full mathematical evaluations of the protocol referred to as "random SFHMA" are presented for the mobile-to-fixed-station channel, and some simulation results are given for the reverse channel. With realistic propagation parameters ( \alpha= 3.5, \sigma = 8 dB) and with mobile power control, there can be as many as 87 radiotelephone users per cell in a 25 MHz band. A comparison to the traditional FDMA protocol is presented and it is Shown that slow frequency hopping would be more efficient for future high capacity small cell systems.