Energy efficiency improvement of mobile terminals exploiting opportunistic scheduling and upper layers´ queuing dynamics

Energy efficient link adaptation can significantly increase energy efficiency on the uplink of cell users. However, `far´ users, users that face unfavorable radio conditions on their uplink, have limited room for improvement with respect to link adaptation. This paper investigates extra ways of increasing energy efficiency for both `far´ and `near´ users, without sacrificing system performance, utilizing properties of the MAC and the upper layers of the network protocols stack and specifically queuing dynamics at the Session Layer. In contrast to common intuition, we show that under a dynamic setting of active flows energy efficiency, especially at high loads, is significantly increased under the Proportional Fair (PF) Scheduling. Moreover, we elaborate on extra transmission opportunities that are apparent due to different service completion times of near and far users, coming up with a simple priority opportunistic strategy that outperforms PF with regards to energy efficiency, without sacrificing throughput. In fact throughput of both far and near users is increased under practically relevant conditions when far users are significantly more than near users.