QoS provisioning in LTE-A networks with relay nodes

Abstract

Abstract-In the vision of heterogeneous networks, the Quality of Service provided by classic cellular systems is improved thanks to a jointly adoption of macro and small-range cells (i.e., micro, pico, and femtocells) working in the same area. This rationale has been also assimilated by 3GPP, which now proposes its possible exploitation in the upcoming Long Term Evolution-Advanced architecture. In this context, the wireless relay technology represents an interesting solution for extending the coverage of a macrocell by means of a relay node which offers wireless connectivity to mobile users and, at the same time, is connected to the eNode-B (and hence to the backbone) through a wireless backhaul link. But, the standard does not specify any optimal resource allocation strategy for the two hop path formed by the user and the backhaul links, which is indeed very relevant to satisfy the level of QoS expected by end users. To this aim, in the present contribution, we present a novel scheduling strategy, conceived as an extension of the recently proposed TwoLevel Scheduler approach, able to effectively support real-time applications in the presence of relay nodes. Its performance has been tested in several network scenarios that involve a variable number of users hosting real-time multimedia applications and best effort flows. A comparison with respect to Proportional Fair and Logarithmic strategies has been also provided, showing that the proposed approach is able to greatly reduce the Packet Loss Ratio experienced by multimedia applications, at the expense of a slight impairment of the throughput of the best effort flows.

Radio Resource Management for Eicic, Comp, Relaying and Back-hauls Techniques in LTE-advanced Networks: Concepts and a Literature Survey

“…In the case of R-UEs, both schedulers had a 100% satisfied user of the two traffic types. The authors of [13] proposed a resource allocation strategy that was able to effectively support and satisfy a QoS level for real-time applications LTE-A network with the existence of relay nodes, this was accomplished by extending their previous proposed Two-Level Scheduler approach in [14]. They adapted their Two-Level Scheduler to the relay technology by applying it to both the DeNB and the relay, and also by splitting the maximum delay on the access network from the DeNB to the terminal τi into two parts as follows:…”

QoS-aware Resource Allocation in Relay-enhanced TD-LTE-A Systems

“…Based on the classical MLWDF algorithm [8] , which possesses great performance in system TH-MLWDF algorithm is proposed in [9] to meet the QoS demands of various traffics in two-hop relay system. With the presence of RNs in the model, delay is divided into two parts as expressed in the formula (3), also shown in Fig.…”

“…D UE-RN and D RN-eNB are preset delay threshold for traffic i from UE to its serving RN and from RN to the eNB, respectively. In [9], the target delays in two-hop links are set as follows:…”

“…D-UEs and R-UEs are no longer competitive relationship, and each node schedules its UEs independently. If the traffic of D-UEs is mixed GBR with Non-GBR traffic, then the scheduling priority formula of D-UEs in backhaul links is also expressed as (9). If all the traffics of D-UEs are GBR traffics, the scheduling priority formula is as follows:…”

“…A low-complexity QoS-aware resource allocation algorithm aiming at maximizing system throughput is proposed in [3] and [4], but they do not consider the effect of delay, which is an influential factor to guarantee QoS. The authors in [5] adopt a two-stage scheduling algorithm at both the evolved NodeB (eNB) and Relay Nodes (RNs). The higher stage scheduling considers the delay demand, while the lower one employs the PF algorithm.…”