Efficient Resource Scheduling by Exploiting Relay Cache for Cellular Networks

Chun He,Haixia Cui,Gang Feng

doi:10.1155/2015/140727

Chun He, Haixia Cui + Show 1 more

Open Access

https://doi.org/10.1155/2015/140727

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Abstract

In relay-enhanced cellular systems, throughput of User Equipment (UE) is constrained by the bottleneck of the two-hop link, backhaul link (or the first hop link), and access link (the second hop link). To maximize the throughput, resource allocation should be coordinated between these two hops. A common resource scheduling algorithm, Adaptive Distributed Proportional Fair, only ensures that the throughput of the first hop is greater than or equal to that of the second hop. But it cannot guarantee a good balance of the throughput and fairness between the two hops. In this paper, we propose a Two-Hop Balanced Distributed Scheduling (TBS) algorithm by exploiting relay cache for non-real-time data traffic. The evolved Node Basestation (eNB) adaptively adjusts the number of Resource Blocks (RBs) allocated to the backhaul link and direct links based on the cache information of relays. Each relay allocates RBs for relay UEs based on the size of the relay UE’s Transport Block. We also design a relay UE’s ACK feedback mechanism to update the data at relay cache. Simulation results show that the proposed TBS can effectively improve resource utilization and achieve a good trade-off between system throughput and fairness by balancing the throughput of backhaul and access link.

Highlights

Driven by explosive increase in the number of users and data usage, the huge communication traffic volume introduces great challenges to mobile network operators
The authors of [16] propose Adaptive Distributed Proportional Fair (ADPF) scheduling algorithm based on PF, which assures that backhaul link throughput of each Relay Node(s) (RN) is greater than or equal to the sum of access link throughput of relay User Equipment (UE) attached to the RN in resource allocation for each RN in order to fully meet the needs of relay UEs
The specific steps of the mechanism are as follows: A save the data received from evolved Node Basestation (eNB) correctly by RN in RN buffer in backhaul downlink subframe; B after relay UEs are scheduled in access downlink subframe, subtract the sum of the relay UEs’ Transport Block (TB) size from RN buffer according to Rbfrsize = Rbfrsize − ∑new TBsize (u) . (10)

Summary

Introduction

Driven by explosive increase in the number of users and data usage, the huge communication traffic volume introduces great challenges to mobile network operators. The authors of [16] propose Adaptive Distributed Proportional Fair (ADPF) scheduling algorithm based on PF, which assures that backhaul link throughput of each RN is greater than or equal to the sum of access link throughput of relay UEs attached to the RN in resource allocation for each RN in order to fully meet the needs of relay UEs. ADPF considers rate matching, ADPF cannot guarantee a good balance between the throughput of backhaul link and the throughput of access link, which will result in a waste of resource and poor fairness. We design a relay UE’s ACK feedback mechanism to update the data cached at RNs. Simulation results show that the proposed TBS can significantly improve system resource utilization and achieve a good trade-off between system throughput and fairness by balancing the throughput of backhaul and access link.

System Model and Preliminary Techniques

Simulation and Evaluation

Conclusion