Buffer-aware resource scheduling scheme for LTE-A uplink relay-assisted network

Due to the constraint of single carrier frequency division multiple access (SC-FDMA) adopted in long term evolution (LTE) uplink, subcarriers allocated to single user equipment (UE) must be contiguous. This contiguous allocation constraint limits resource allocation flexibility and makes the resource scheduling problem more complex. Most of the existing work cannot well meet UE's quality of service (QoS) requirement, because they just try to improve system performance mainly based on channel condition or buffer size. This paper proposes a novel resource scheduling scheme considering channel condition, buffer size and packet delay when allocating frequency resource. Firstly, optimization function is formulated, which aims to minimize sum of weight for bits still left in UE buffer after each scheduling slot. QoS is the main concern factor here. Then, to get packet delay information, this paper proposes a delay estimation algorithm. Relay node (RN) is introduced to improve overall channel condition. Specific RN selection strategy is also depicted in the scheme. Most important of all, a creative negotiation mechanism is included in the subcarrier allocation process. It can improve the overall system throughput performance in guarantee of user's QoS requirement. Simulation results demonstrate that the scheme can greatly enhance system performance like delay, throughput and jitter.