A hierarchical proportional fair scheduler

In 3G wireless networks, opportunistic schedulers take advantage from the delay-tolerance of data applications to ensure that transmission occurs when radio channel conditions are most favourable. In the well-known opportunistic scheduler "proportional fair" (pf), the base station (BS) serves only one user per time slot which is optimal when the signal-to-noise ratio (SNR) scales linearly with the effective transmission rate. However, for a logarithmic relation between the channel quality and the transmission rate, scheduling one user at a time does not always result in maximum channel utilization. For that reason, we put forward in this paper a new scheduler that divides the cell into two categories, serving alternately the first one in a CDMA fashion and the second one according to the PF scheduler. The mathematical and simulation analysis provided proves that the proposed scheduler increases the overall throughput of the cell