Mobile Multi-hop Relay Networks Research Articles

Secure and Efficient Distributed Relay-Based Rekeying Algorithm for Group Communication in Mobile Multihop Relay Network

In mobile multihop relay (MMR) networks, Relay multicast rekeying algorithm (RMRA) is meant to ensure secure multicast communication and selective updating of keys in MMR networks. However, in RMRA, the rekeying is carried out after a specific interval of time, which cannot ensure the security for multicast communication on joining the member. Secondly, the rekeying scheme generates a huge communication overhead on the serving multihop relay base station (MR-BS) on frequent joining of members. Lastly, there is nothing about when a member left the group communication. Thus, the rekeying scheme of RMRA fails to provide forward and backward secrecy and also is not scalable. To solve this problem, an improved rekeying scheme based on broadcasting a new seed value on joining and leaving of a member for updating the ongoing key management is proposed. The proposed scheme solves the issue of forward and backward secrecy and the scalability in a very simplified way. The forward and backward secrecy of the proposed scheme has been extensively validated by formal method using rank theorem. Furthermore, mathematical derivation showed that the proposed scheme out-performed the RMRA in terms of communication cost and complexity.

Secure and Scalable Group Rekeying for Mobile Multihop Relay Network

Secure and Scalable Group Rekeying for Mobile Multihop Relay Network

RELAY SELECTION IN MOBILE MULTIHOP RELAY NETWORK

Mobile Multihop Relay (MMR) network is an attractive and low-cost solution for expanding service coverage and enhancing throughput of the conventional single hop network. However, mobility of Mobile Station (MS) in MMR network might lead to performance degradation in terms of Quality of Service (QoS). Selecting an appropriate Relay Station (RS) that can support data transmission for high mobility MS to enhance QoS is one of the challenges in MMR network. The main goal of the work is to develop and enhance relay selection mechanisms that can assure continuous connectivity while ensuring QoS in MMR network using NCTUns simulation tools. The approach is to develop and enhance relay selection that allows cooperative data transmission in transparent relay that guarantees continuous connectivity. The proposed relay selection defined as Co-ReSL depends on weightage of SNR, 𝛼 and weightage of Link Expiration Time (LET), β. The QoS performances of the proposed relay selections are in terms of throughput and average end-to-end (ETE) delay. The findings for Co-ReSL shows that at heavy traffic load, throughput increases up to 5.7% and average ETE delay reduces by 7.5% compared to Movement Aware Greedy Forwarding (MAGF) due to cooperative data transmission in selective links. The proposed relay selection mechanisms can be applied in any high mobility multi-tier cellular network.

CONNECTIVITY IN MOBILE MULTIHOP RELAY NETWORK

Mobile Multihop Relay (MMR) network is an attractive and low-cost solution for expanding service coverage and enhancing throughput of the conventional single hop network. However, mobility of Mobile Station (MS) in MMR network might lead to performance degradation in terms of Quality of Service (QoS). Selecting an appropriate Relay Station (RS) that can support data transmission for high mobility MS to enhance QoS is one of the challenges in MMR network. The main goal of the work is to develop and enhance relay selection mechanisms that can assure continuous connectivity while ensuring QoS in MMR network using NCTUns simulation tools. The approach is to develop and enhance a relay selection for MS with continuous connectivity in non-transparent relay. In this approach, the standard network entry procedure is modified to allow continuous connectivity with reduced signaling messages whenever MS joins RS that is out of Multihop Relay Base Station (MRBS) coverage and the relay selection is based on Signal to Noise Ratio (SNR). The QoS performances of the proposed relay selections are in terms of throughput and average end-to-end (ETE) delay. The findings for the proposed relay selection in non-transparent relay shows that the throughput degradation between low mobility MS (30m/s) and high mobility MS (50m/s) is only about 2.0%. The proposed relay selection mechanisms can be applied in any high mobility multi-tier cellular network.

Analyses of Relay Nodes Deployment in 4G Wireless Mobile Multihop Relay Networks

In 4G cellular networks: LTE/LTE-Advanced and the mobile WiMAX network, some key impact factors: white Gaussian noise, wireless interference, shadow fading, etc., degrade signal transmission quality and reduce wireless service coverage significantly. The degradations can be improved by deploying more eNBs or BSs, but the expensive eNB/BS extremely increases network cost. The specifications of LTE-Advanced and IEEE 802.16j thus propose a relay-based scheme, namely mobile multihop relay (MMR) networks, to cooperate with the existing cellular network while not obviously increasing the relay station (RS) deployment cost. Various types of RSs: Fixed RS, Nomadic RS and Mobile RS, can be adopted in MMR networks. To efficiently deploy different types of RSs becomes a critical issue. Thus, this paper first analyzes the impact factors: transmission quality, deployment price, service coverage and RS overlap index, and then models the cost-effective issue of the RS deployment as an optimization problem. The paper proposes an adaptive cost-based RS deployment (ACRD) approach to form a cost function in terms of all impact factors, and then solves the optimization problem by determining the RS deployment with the least network cost as the solution. Numerical results demonstrate that ACRD outperforms the compared approaches in network cost, transmission quality, RS deployment price, service coverage, and RS overlap index. Additionally, ACRD deploys more RSs on the areas with high-density populations and thus increases transmission quality and guarantees the quality of service (QoS). Finally, the worst case running time of ACRD is analyzed, which requires $$ T(n) = O(I \cdot P) $$T(n)=O(I·P).

Secure Authentication and Key Management Protocols for Mobile Multihop WiMAX Networks

Mobile Multihop Relay (MMR) network is one of the emerging technologies, especially LTE-Advanced, WiMAX and the Smart grid communications. Ensuring security is one of the most imperative and challenging issues in MMR networks. Privacy Key Management (PKM) protocol is proposed to ensure the security measures in MMR networks. However, the protocol still faces several security threats, specifically Denial of Service (DoS), replay attacks, Man in the Middle (MitM) attacks and the interleaving attacks, which is termed as Medium Access Control (MAC) layer attacks. This paper proposed a modified version PKM protocol for both unilateral and mutual authentication, which is termed as Self-organized Efficient Authentication and Key Management Scheme (SEAKS) authentication protocol. This protocol ensures secure end-to-end data transmission using distributed hop-by-hop authentication and localized key management schemes with a very simple and efficient way.

Lightweight Message Authentication Protocol for Mobile Multihop Relay Networks

This paper proposes a lightweight self-organized efficient authentication and key management scheme (SEAKS) to countermeasure the MAC layer attacks such as denial of service (DoS), replay attack, man-in-the-middle attack and the interleaving attacks in mobile multihop relay (MMR) networks. SEAKS has been developed based on privacy key management (PKM) protocol for both unilateral authentication defined as SEAKS-PKMv1 and mutual authentication as SEAKS-PKMv2. In SEAKS, the non-transparent relays (N-RS) perform authentication and establish the authorization key (AK) using our proposed public key cryptosystem based on hash authentication code scheme. The subsequent N-RS can be authenticated with less overhead thus enhancing the scalability of the system. The performance of SEAKS-PKMv1 and SEAKS-PKMv2 protocol has been evaluated using BAN LOGIC to verify the integrity of the participating N-RSs and SSs. Simulation study shows that SEAKS exhibits higher packet delivery ratio by 22%, lesser packet overhead by 12%, and less processing time by 14% as compared to the official draft scheme (OD-2009) for MMR WiMAX networks. SEAKS can be applied to any multihop networks with minimum authentication overhead.

Handover rate based dynamic guard bandwidth allocation method for call admission control in IEEE 802.16j Mobile Multihop Relay networks

IEEE 802.16j MMR (Mobile Multihop Relay) networks are developed to extend the coverage area and enhance the throughput of IEEE 802.16 networks. Call Admission Control (CAC) is an important research issue related to these networks. In this paper, a novel dynamic guard bandwidth allocation method is proposed for CAC in IEEE 802.16j networks; the guard bandwidth allocated at a station depends upon the handover rates from its neighbors and at its descendent stations. A bandwidth wastage prevention policy is proposed to utilize the unused guard bandwidth to fulfill the requests of lower priority calls and eventually to improve the bandwidth utilization of the network. Based on the total amounts of the guard bandwidth received by the lower priority calls, a novel bandwidth borrowing scheme is proposed. A Markov model is developed to analyze the performance of the proposed CAC method; analytical handover call dropping probabilities and new call blocking probabilities of various service classes are obtained using the proposed Markov model. Simulation experiments are conducted to compare the performance of the proposed CAC method with a fixed guard bandwidth based CAC method. The proposed method showed superior performance than the fixed guard bandwidth based method. Also, the simulation results are compared with the analytical results.

PSFCS: Robust Emergency Communications Supporting High Mobility Based on WiMAX MMR Networks

Nowadays public safety networks are widely deployed to support highly reliable wireless communications in case of emergency. The adoption of standardized systems such as WiMAX for emergency communications represents a significant advance in the off-the-shelf technologies for error detection and error correction. Since it is difficult to fully eliminate the Doppler effect under high speed moving environment, we propose an enhanced CRC-based error correction scheme that carries as much extra segmented frame Check Sequence (FCS) information as subblocks of emergency multicast/broadcast service (MBS) frame, called progressive and selective frame check sequence (PSFCS). In a mobile multihop relay (MMR) environment, a high-mobility mobile station might receive an emergency MBS frame more than once, so the PSFCS could be cross-referenced by duplicated frames received. Therefore the PSFCS achieves a significant performance improvement over the legacy FCS scheme in terms of error detection and correction of emergency MBS frames in a WiMAX MMR network operating in transparent mode. The experimental results show that the goodput and utilization of high-mobility mobile stations can be improved remarkably.

High Capacity Mobile Multi-Hop Relay Network for Temporary Traffic Surge

Mobile Multi-hop Relay (MMR) technology is usually used to increase the transmission rate or to extend communication coverage. In this work, we show that MMR technology can also be used to raise the network capacity. Because Relay Stations (RS) are connected to the Base Station (BS) wirelessly and controlled by the BS, an MMR network can easily be deployed when necessary. High capacity MMR networks thus provide a good candidate solution for coping with temporary traffic surges. For the capacity enhancement of the MMR network, we suggest a novel scheme to parallelize cell transmissions while controlling the interference between transmissions. Using a numerical example for a typical network that is conformant to the IEEE 802.16j, we find that the network capacity increases by 88 percent.

Link Quality Based Path Selection Methods for IEEE 802.16j Mobile Multihop Relay Networks

IEEE 802.16j mobile multihop relay (MMR) networks are developed to enhance the coverage area and the throughput of IEEE 802.16 networks. Path selection is an important research problem related to these networks. In the networks where the link qualities are highly varying, to provide consistent quality of service to the users, it is very important to select paths consisting of links with consistent link qualities. To address this issue, in this paper, two path consistency based path selection methods are proposed for IEEE 802.16j MMR networks. Through simulations, the performance of the method proposed for the mobile nodes is compared with the performance of two path selection methods proposed in the literature. It is observed that the proposed method provides better performance than the methods selected from the literature.

Network planning for mobile multi-hop relay networks

In this paper, the coverage problem of network planning in mobile multi-hop relay networks is defined on the basis of integer linear programming. In order to provide desired utilities and also meet deployment limitations for network planning, we propose a supergraph tree algorithm to place base stations and relay stations at the lowest cost position. Furthermore, another algorithm for avoiding the interference between base stations, which is called interference aware tree algorithm is also proposed. Both the proposed algorithms are formulated on the basis of a graph theoretic technique and analyzed in the simulation results. The results show that the supergraph tree algorithm provides the lowest construction cost with different network scenarios, and the interference aware tree algorithm provides the highest communication quality for mobile multi-hop relay infrastructure-based communication network planning. Copyright © 2013 John Wiley & Sons, Ltd.

Intrusion tolerant QoS provision in mobile multihop relay networks

We propose in this article an architecture called trusted timely attacks-tolerating communication architecture (3TCA) designed for mobile multihop relay (MMR) networks. The 3TCA architecture is based on trusted components providing trusted time-related and security-related services along with an intrusion-related service while guaranteeing QoS compensation. 3TCA components are implemented at access nodes such as relay stations (RSs) and multihop relay base stations (MR-BSs) in order to achieve trusted QoS-aware handover management while guaranteeing intrusion tolerance. In particular, we provide QoS guarantees in terms of delay, bandwidth and jitter for the MMR networks while addressing group mobility through performing handover disturbance compensation for mobile RSs. Meanwhile, we tolerate particular timely-based and DoS attacks through compensating their impact on the already agreed QoS level. Simulations show that adopting compensation is suited for the MMR context although it induces additional complexity.

Secure Authentication and Key Management Protocols for Mobile Multihop WiMAX Networks

Mobile Multihop Relay (MMR) network is one of the emerging technologies, especially LTE-Advanced, WiMAX and the Smart grid communications. Ensuring security is one of the most imperative and challenging issues in MMR networks. Privacy Key Management (PKM) protocol is proposed to ensure the security measures in MMR networks. However, the protocol still faces several security threats, specifically Denial of Service (DoS), replay attacks, Man in the Middle (MitM) attacks and the interleaving attacks, which is termed as Medium Access Control (MAC) layer attacks. This paper proposed a modified version PKM protocol for both unilateral and mutual authentication, which is termed as Self-organized Efficient Authentication and Key Management Scheme (SEAKS) authentication protocol. This protocol ensures secure end-to-end data transmission using distributed hop-by-hop authentication and localized key management schemes with a very simple and efficient way. The performance evaluation of the proposed schemes in terms of packet delivery ratio, packet overhead, processing time and the effect of increasing number of rogue relay stations is carried out and compared with the official draft of MMR WiMAX and the SEN XU. The result showed that our proposed scheme out-performed the base line protocols. Keywords: Denial of Service, Hop-by-Hop Authentication, IEEE 802.16, MMR WiMAX Network, Security Issues

A New Distributed Scheduling Algorithm for Bandwidth Allocation in IEEE 802.16 Mesh Networks

Multi-hop WiMAX networks has the potential of easily providing high-speed wireless broadband access to areas with little or no existing wired infrastructure. IEEE 802.16 incorporates the quality of service (QoS) mechanisms at the Media Access Control (MAC) level, but it doesn’t define a specific allocation algorithm. The implementation was left open to the service providers’ diligence. Scheduling in WiMAX became one of the most challenging issues, since it was responsible for distributing available resources of the network among all users. Providing QoS in multi-hop WiMAX networks such as WiMAX mesh or mobile multihop relay networks is challenging as multiple packets can collide if they are scheduled at the same time. To warranty the QoS requirements, the 802.16 equipment must run some algorithm to allocate slots for connections. We propose an efficient distributed algorithm for packets scheduling in multi-hop WiMAX mobile networks. It is based on the 802.16e parameters, bandwidth request sizes and QoS requirements. The algorithm ensures a dynamic bandwidth allocation for the 802.16 various service classes. Assuming that the packets arrivals follow a Poisson process we build an algorithm witch calculate the number of time slots required for each packet according to its service class and its length.

Multicast Gain for IPTV Transmission in WiMAX Multi-hop Relay Networks

Due to characteristics such as: multicast support, wide coverage range, high bandwidth and mobility support, WiMAX could be a leading solution to deliver bandwidth-hungry IPTV services to mobile users. Mobile multi-hop relay (MMR) was proposed as an amendment of the current mobile WiMAX standard to provide relaying capabilities. Relays are deployed as a cost-effective solution to extent coverage area and increase throughput without deploying expensive base stations. In this paper, we introduce multicast gain as a performance criterion, which can be used for computing multicast efficiency. In order to quantify the benefits of multicasting, we analyze multicast transmission for delivery of live TV channels in MMR networks, and determine the gain of access and relay links. The quantification of the efficiency of multicasting can be used by IPTV service providers in resource provisioning, access control or decision support mechanisms in delivery of different TV channels.

Bandwidth negotiation scheduling with dynamic zone adjustment for 802.16j mobile multihop relay networks

ABSTRACTThis paper presents a bandwidth negotiation scheduling (BNS) for IEEE 802.16j mobile multihop relay (MMR) networks. In MMR networks, two bandwidth scheduling zones, Access and Relay zones, are specified for direct access and forwarding sessions, respectively. One of the novelties in the proposed BNS is that bandwidth negotiation is conducted between the Access and Relay zones. In other words, a higher‐priority traffic class in a high‐utilization zone may receive extra bandwidth from low‐utilization zone when its delay constraint or bandwidth requirement cannot be satisfied. In addition, when the assigned bandwidth to non‐real‐time polling service (nrtPS) has exceeded its minimum requirement, the proposed BNS can avoid possible starvations for best effort (BE) traffic by receiving extra bandwidth from nrtPS. Through multidimensional Markov formulation, we evaluate the performance of the BNS and compare it with a fixed‐boundary scheme. The analytical results have shown that the proposed BNS can increase delay‐constraint satisfactions for real‐time polling service and decrease the packet loss rate for BE. Furthermore, the overall system throughput can be increased significantly because of an improvement on bandwidth utilization. Copyright © 2012 John Wiley & Sons, Ltd.

A Survey on Technical Issues in IEEE 802.16j Mobile Multi-hop Relay Networks

In this paper, we have conducted a detailed survey on relay technologies for IEEE 802.16j mobile multi-hop relay networks, such as relay modes, relay transmission schemes, and relay pairing schemes. We have also conducted a detailed survey about the technical issues in the physical layer, medium access control-common part sub layer, and medium access control-security sub layer of IEEE 802.16j mobile multi hop relay networks. Technical issues such as data forwarding schemes, frame structure for transparent and non-transparent relay mode, link adaptation, modulation, and coding, belong to the physical layer. Other technical issues such as quality of service-scheduling services, bandwidth allocation and request, network planning, medium access control handover procedures, connection management, path management, and interference management belong to the medium access control- common part sub layer. Centralized security control and distributed security control belong to the medium access control--security sub layer. In this paper, we have also given how to integrated IEEE 802.16j (worldwide interoperability for microwave access) with IEEE 802.11(Wi-Fi).

An Efficient Link Aware Route Selection Algorithm for WiMAX Mobile Multihop Relay Networks

Multi-hop relay technology is designed to provide capacity enhancement and coverage extension for wireless broadband access system such as WiMAX and LTE-Advanced. However, overall system performances worsen as the number of hop increases. For this reason, resource control function specifically route selection problem should be tackled precisely so that better system performance can be achieved. Route selection or routing is a process to identify the best route to deliver information from source to destination by considering the constraints of available radio resource of the route. In this paper, we proposed a new route selection scheme named as Link Aware Route Selection Scheme (LARSS) for WiMAX Mobile Multi-hop Relay Networks aiming at maximizing network throughput and minimizing end-to-end delay. The proposed scheme exploits link quality and hop count as route metric. We conducted simulation study to evaluate the performance of the proposed scheme. Through the simulation, our proposed scheme outperformed the existing scheme in term of throughput and end-to-end delay.

Performance analysis of authentication and key distribution scheme for mobile multi-hop relay in IEEE 802.16j

Mobile multi-hop relay (MMR) network is known to be easy to install and convenient to manage because of its self-organizing and self-healing characteristics. However, MMR is vulnerable to security problems because of the same reason. In this paper, we propose a new hybrid authentication and key distribution algorithm for IEEE 802.16j MMR service. The proposed scheme uses centralized authentication when a mobile station or a relay station initially joins the MMR network and uses distributed authentication for hop-by-hop authentication between mobile nodes. We examine the procedure of the proposed scheme and its usefulness when applied to MMR networks. We also analyze the performance of the hybrid scheme. The proposed scheme can be used in any mobile multi-hop network as well as IEEE 802.16j MMR network.