Method of packet scheduling, with improved delay performance, for wireless networks

摘要

A new scheduling discipline is disclosed for the forward link of a wireless network such as a CDMA network. The new discipline, which we denominate Modified LWDF (M-LWDF), resembles the known LWDF discipline in that only one queue is served at a time, and the queue to be served is that having the largest weighted delay. According to M-LWDF, the weighted delay of the i'th queue is defined as $\mathop{\mathrm{image}}$ \frac{{\mathrm{\γ}}_i\⁢W_i\⁡\left(t\right)}{c_i\⁡\left(t\right)},$$;wherein W_i(t) is a packet delay, a queue length, or an increasing function of packet delay or queue length for the i'th queue, c_i(t) is a weight coefficient descriptive of channel conditions for the i'th user, and &ggr;_i is a fixed constant that can be chosen arbitrarily. We have found that if any scheduling discipline can yield stable queues for a given traffic pattern of arriving packets, then M-LWDF can, even under changing channel conditions. Moreover, we have found that M-LWDF can provide favorable QoS in terms of delay bounds.