  In current cellular networks, schedulers allocate wireless channel resources
to users based on instantaneous channel gains and short-term moving averages of
user rates and queue lengths. By using only such short-term information,
schedulers ignore the users' service history in previous cells and, thus,
cannot guarantee long-term Quality of Service (QoS) when users traverse
multiple cells with varying load and capacity. In this paper, we propose a new
Long-term Lookback Scheduling (LLS) framework, which extends conventional
short-term scheduling with long-term QoS information from previously traversed
cells. We demonstrate the application of LLS for common channel-aware, as well
as channel and queue-aware schedulers. The developed long-term schedulers also
provide a controllable trade-off between emphasizing the immediate user QoS or
the long-term measures. Our simulation results show high gains in long-term QoS
without sacrificing short-term user requirements. Therefore, the proposed
scheduling approach improves subscriber satisfaction and increases operational
efficiency.
