A red-based discard strategy for unacknowledged mode RLC in LTE

In order to satisfy the increasing demands of wireless mobile communications, Long Term Evolution (LTE) has been proposed as an all-IP-based network to bring higher peak data rates and better spectral efficiency. As one of the sub-layers of LTE, Radio Link Control (RLC) layer is likely to congest or overflow due to handover or undesirable channel condition. In this paper, based on Random Early Detection (RED), a discard strategy is proposed for Unacknowledged Mode (UM) RLC to overcome the congestion and buffer overflow problems. Taking LTE systems into account, a simpler improved RED discard strategy is proposed, which is suitable to the delay-sensitive stream that transmitted by a UM RLC entity. This discard strategy can be employed in UE for uplink or evolved NodeBs (eNB) for downlink. The delay and discard performances of the proposed discard strategy are evaluated by both computer simulations and theoretical analysis. According to the simulation results, some suggestions about configuring parameters of the proposed discard strategy are given. In the end, to systematize the strategy and make it more practical, a cross-layer specific proposal is proposed.