Abderrahmane BenMimoune

Inter-cell handoff performance improvement in LTE-a multi-hop relay networks

Multi-hop relay technology is one of the most promising candidate technologies to overcome the coverage and capacity problem in LTE-Advanced networks. Currently 3GPP is considering the incorporation of multi-hop relays into Release 12 of LTE-A standards. However, many issues remain to be resolved due to the complexity of multi-hop relaying paradigm, specifically resource allocation and mobility management. In this work we focus on the relay selection problem, where a user may have in his range several relay nodes to choose. The conventional selection scheme is based on the channel condition between the relay and the user, such that the user will achieve a high level of throughput. Alternatively we propose in this paper a novel relay selection strategy taking handoff into account over LTE-A multi-hop relay networks. Our goal is to achieve significant performance improvement against legacy centralized resource allocation and handoff algorithms such as disjoint path relay selection. Simulation results show that our design has the advantage of reducing inter-cell handoff frequency and lowering handoff failure ratio.

Resource Allocation Framework in 5G Multi-Hop Relay System

Cellular relaying architecture is in an early stage for development and deployment. A restricted number of deployment scenarios are addressed in the LTE-A relay standard, though different design options in alternative deployment scenarios do potentially exist. Presently, the LTE-A relay standard is restricted to a single-hop relaying. The principal reason for opting for this architecture is to minimize system complexity. Nonetheless, multi-hop relay architecture could potentially provide greater capacity and coverage, in the future, particularly for urban sparse area deployment scenarios. However, many problems involving the complexity of multi-hop relaying paradigm need to be resolved, specifically resource management. In this paper, we focus on the resource management problem, and we propose a new resource allocation framework to overcome the additional challenges introduced by the multi-hop relay stations. Numerical results are presented to demonstrate the validity of the proposed framework.

User Association for HetNet Small Cell Networks

Heterogeneous networks principally composed of macro-cells overlaid with small cells (e.g., Femtocells, pico-cells, and relays) can potentially improve the coverage and capacity of existing cellular networks and satisfy the growing demands of data throughput. In Het Nets, small cells play a key role in offloading user data traffic from congested macro-cells and extending the limited coverage of macro-cells. However, the use of small cells is still impeded by the issues of coexistence and efficient operation, as small cells are characterized by limited resources, large-scale random deployment, and a lack of coordination. In this paper, we focus on user association problem in Het Net, and we propose a new scheme by applying the Voronoi diagram, a powerful computational geometry technique, to solve the user connection problem in which a user has several stations within his range from which to choose. Simulation results show that our proposed scheme can significantly increase the number of admitted users and system throughput.

Predictive Congestion Avoidance in Wireless Mesh Network

Congestion avoidance is a vital part in improving the Quality of service (QoS) in Wireless Mesh Network (WMN). A preventive congestion avoidance algorithm is proposed in this paper which predicts the congestion before it really happens in the network by using different statistical analysis models which analyze historical traffic data in the network with some level of certainty to predict the future traffic data. Our proposed algorithm improves the Hybrid Wireless Mesh Protocol (HWMP) routing protocol used in IEEE 802.11s MAC layer standard. Based on the predicted link congestion, rerouting algorithm is implemented in order to assure the load balancing and to prevent congestion over WMN network. Simulation results show that our proposed algorithm outperforms other algorithms in the literature in terms of throughput, end-to-end delay, and fairness.

Multihoming admission and mobility management in wireless mesh network

Admission control is an important component to control the acceptance of new calls without degrading the Quality of Service (QoS) of the existing calls in the wireless mesh network. Two types of calls are existing in the network which are the new and handoff calls, in order to increase the admission rate for both types of calls a multi-homing admission and mobility management algorithm is proposed, which associates the user with two different access points which is most beneficial in case of highly congested network. Simulation results show that our proposed algorithm decreases the blocking probability for new and handoff calls.

Dynamic joint resource allocation and relay selection for 5G multi-hop relay systems

LTE/LTE-A networks have become widely exploited to address the increasing demands of mobile traffic. Relay technologies have recently been introduced to fulfill such requirements. Currently, the LTE-A relay standard is restricted to two-hop relaying. This architecture minimizes system complexity, but multi-hop relay architecture could potentially provide greater capacity and coverage in the future. However, many complexities of the multi-hop relaying paradigm must be resolved. In this work, we focus on downlink resource allocation and relay selection, by which a user may be connected to a base station through a multi-hop relay and have several relay stations from which to choose within his range. To overcome the additional challenges introduced by multi-hop relay nodes, we propose a dynamic joint resource allocation and relay selection scheme. Numerical results are presented to demonstrate the validity of the proposed algorithm.

User association-based joint admission and power control for heterogeneous wireless networks

Heterogeneous networks (HetNets) principally composed of macro-cells overlaid with small cells can potentially improve the coverage and capacity of existing cellular networks and satisfy the growing demands of data throughput. In HetNets, small cells play a key role in offloading user data traffic from congested macro-cells and extending the limited coverage of macro-cells. However, the use of small cells is still impeded by the issues of coexistence and efficient operation, as small cells are characterized by limited resources, large-scale random deployment, and a lack of coordination. In this paper, we focus jointly on call admission control and the power allocation problem in HetNet, and we propose a new user association scheme by applying the Voronoi diagram, a powerful computational geometry technique, to solve the user connection problem in which a user has several stations within his range from which to choose. Simulation results show that our proposed scheme can significantly increase the number of admitted users and system throughput, lower the call-blocking ratio, and enhance energy efficiency.

Relay Technology for 5G Networks and IoT Applications

Relaying technologies have been actively studied in mobile broadband communication systems, and were considered in the most recent standard releases of the Third Generation Partnership Project (3GPP), including “Long Term Evolution Advanced” (LTE-A) networks. This chapter provides an in-depth review of the relay technology that is being considered for future 5G networks. The article first introduces and compares different relay types that use LTE-A standards, and presents the relay benefits in terms of performance and operational costs. It then highlights future relay deployment strategies that have been discussed by the 3GPP, which supports multi-hopping, mobility, and heterogeneity. In addition, it also proposes efficient deployment strategies, along with their impact on network performance. Finally, the chapter explains a few of the associated challenges that lie ahead for relay application, and provides a video streaming application.

Joint path relay selection in 5G multi-hop relay networks

Multi-hop relaying has been considered as a key technology for future wireless communication networks to overcome coverage and capacity problems in 5th generation mobile networks (5G). Recently, there has been increasing interest from 3GPP operators to integrate multi-hop relaying functionalities into LTE-A standards. However, many issues remain to be resolved due to the complexity of the multi-hop relaying paradigm, specifically resource allocation and mobility management. In this work, we focus on the relay-selection problem, in which a user may have in his range several relay stations from which to choose. The conventional selection scheme is based on the channel condition between the relay and the user, such that the user will achieve a high level of throughput. Instead, we propose a novel relay selection strategy based on Markov Decision Process (MDP) for multi-hop relay networks. Our goal is to achieve significant performance improvement against legacy, centralized relay selection strategies such as the disjoint-path selection scheme. Simulation results show that our design has the advantage of reducing inter-cell handoff frequency and lowering handoff delay.

Dual-Backhaul Links in LTE - A Mobile Relay System for High-Speed Railways

Serving hundreds of User Equipments onboard of a high-speed train is a very big challenge in terms of resources and mobility management. In addition to the high penetration loss, direct connection between the Evolved Node B and fast User Equipment leads to increased handoff failure rate, and increased power consumption of Vehicular User Equipments. Moreover, sufficient bandwidth may not be gotten from only one Macro Evolved Node B to cover the required throughput of the large-number of diverse-operators User Equipments. Mobile Relay mechanism has been introduced in Release 12 of LTE-Advanced system to be one of the most significant solutions to solve some of these issues. Usually, Mobile Relays are installed on the roof of the train and act as small nodes. In our work, we are considering using the Carrier Aggregation scheme to provide the sufficient bandwidth through a dual-backhaul connection with two Macro base stations. The proposed work makes the group Handoff more seamless as well as improves the user throughput. Simulation results show better performance in terms of system throughput, blocking probability, and packet loss.