Shahbaz Akhtar Abid

A Survey on DHT-Based Routing for Large-Scale Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) are infrastructureless and distributed communication systems that require sophisticated approaches to routing to cope with node mobility and heterogeneous application requirements. In the past few years, distributed hash table (DHT) has come forth as a useful additional technique to the design and specification of spontaneous and self-organized networks. Researchers have exploited its advantages by implementing it at the network layer and developing scalable routing protocols for MANETs. The implementation of DHT-based routing in a MANET requires different algorithms and specifications compared to routing in the Internet because a MANET has its unique characteristics, such as node mobility, spontaneous networking, decentralized architecture, limited transmission range, dynamic topology, and frequent network partitioning/merging. In this article, we present a comprehensive survey of research related to DHT-based routing that aims at enhancing the scalability of MANETs. We present a vivid taxonomy of DHT-based routing protocols and the guidelines to design such protocols for MANETs. We compare the features, strengths, and weaknesses of existing DHT-based routing protocols and highlight key research challenges that are vital to address. The outcome of the analysis serves as a guide for anyone willing to delve into research on DHT-based routing in MANETs.

3D P2P overlay over MANETs

We study the challenging problems of the mismatch between the overlay and the physical network and the resilience of the overlay structure in peer-to-peer (P2P) protocols over a mobile ad hoc network (MANET). Existing P2P protocols have used inflexible overlay structures to arrange peers and do not consider intra-neighbor relationships of peers when assigning logical identifiers. The intra-neighbor relationships of peers are crucial to exactly interpret the physical proximity of peers in an overlay and to avoid the mismatch between the overlay and the physical network that causes extensive routing overhead, larger average file discovery delay, increased false-negative ratio, and high average path-stretch. In this paper, we present a novel P2P overlay over MANETs that exploits a 3-dimensional overlay and 3D space that takes into account the physical intra-neighbor relationship of a peer and exploits a 3D-overlay to interpret that relationship. In the proposed protocol, each peer runs a distributed algorithm that exploits a 3D-overlay to calculate a consecutive logical identifier to a peer. Moreover, the protocol utilizes the 3D-overlay to maintain multi-paths to a destination peer that provides resilience against a node/link failure. Simulation results show that the proposed 3D-overlay outperforms the existing P2P overlay protocol in terms of routing overhead, average file-discovery delay, false-negative ratio, and average path-stretch.

MobiByte: An Application Development Model for Mobile Cloud Computing

Mobile cloud computing presents an effective solution to overcome smartphone constraints, such as limited computational power, storage, and energy. As the traditional mobile application development models do not support computation offloading, mobile cloud computing requires novel application development models that can facilitate the development of cloud enabled mobile applications. This paper presents a mobile cloud application development model, named MobiByte, to enhance mobile device applications’ performance, energy efficiency, and execution support. MobiByte is a context-aware application model that uses multiple data offloading techniques to support a wide range of applications. The proposed model is validated using prototype applications and detailed results are presented. Moreover, MobiByte is compared with the most recent application models with a conclusion that it outperforms the existing application models in many aspects like energy efficiency, performance, generality, context awareness, and privacy.

3D-RP: A DHT-based Routing Protocol for MANETs

In the last few years, distributed hash table (DHT) has come forth as a useful addition to the design andspecificationofspontaneous,self-organizingnetworks.Researchershaveexploiteditsadvantages by implementing it at the network layer in order to design scalable routing protocols for mobile ad hoc networks. We identify two correlated issues that must be considered when designing DHTbased routing protocol, namely the mismatch problem and resilience of the logical network, which degrades the efficiency of the DHT-based routing protocols. To address these problems, we propose a DHT-based routing protocol that exploits a 3D logical space that takes into account the physical intra-neighbor relationships of a node and exploits a 3D structure to interpret that relationship. In the proposed scheme, each node runs a distributed algorithm to obtain a consecutive logical identifierthatreflectsitsphysicalproximityinthe3Dlogicalspace.Moreover,theprotocolutilizesthe 3D-structuretomaintainmulti-pathstoadestinationnodeinordertoaddressthescalabilityproblem and gain resilience against a node/link failure. Simulation results show that the proposed approach outperforms the existing DHT-based routing protocol in terms routing overhead, end-to-end delay, path-stretch values and packet-delivery ratio.

Exploiting 3D Structure for Scalable Routing in MANETs

Avoiding the mismatch between a physical network (PT) and a logical identifier structure (LIS) in a distributed hash table (DHT) based routing for mobile ad hoc networks (MANETs) would prevent the problems of long routes, high path-stretch ratio, and increased traffic overhead. To address this mismatch problem, the proposed scheme exploits a 3-dimensional (3D) logical identifier space (LS), where each node computes a consecutive logical identifier (LID) to route packets. The proposed scheme also utilizes 3D-logical identifier structure (3D-LIS) to maintain multi-paths by exploiting multihops at a node to the destination node. Simulation results show that the proposed protocol is better than existing DHT-based routing protocol.

Optimised priority assignment mechanism for biomedical wireless sensor networks

Biomedical wireless sensor networks (BWSNs) need to guarantee reliable and timely transfer of crucial data in emergency and time critical situations. Current schemes use static/fixed priority assignment mechanism based on source of data and not on the urgency of the data in different situations. This study presents a novel data transmission scheme, called optimised priority assignment mechanism (OPAM) for BWSNs. The proposed work dynamically schedule different types of data flows based on their time critical nature. It smartly assigns priority to individual data packets rather to particular service or flow by continuously monitoring queuing delay providing guaranteed end-to-end quality of service (QoS) without invoking any congestion control and avoidance mechanism. Experimental results show that OPAM performs better in terms of average throughput and end-to-end delay 55 and 20.5%, respectively, than routing service framework for standard BWSNs.

Beaconless multihop routing protocol for wireless sensor networks

Routing is a major challenge in sensor networks, due to constrained resources of energy, processing power, and memory. This proves that there is an urgent need to design energy efficient routing protocols for sensor networks for prolonging network lifetime. This paper presents a new beaconless multihop routing algorithm (BMR) for wireless sensor networks which is light weight, energy efficient and makes routing decisions based on residual energy of nodes. Additionally BMR is a non-positioned beaconless routing protocol which eliminates the overhead of control messages exchanged during network setup in cluster based routing protocols. The proposed protocol first divides the whole network into different zones using message passing techniques by Base Station (BS) and performs energy efficient location base routing without taking any assumption of location services. A simulation-based evaluation is conducted to compare the performance of BMR against energy efficient protocol with static clustering for wireless sensor networks (EEPSC). Simulation results show that BMR performs better than EEPSC in terms of network lifetime and energy consumption minimization.

A survey of P2P content sharing in MANETs

Recently, several approaches have been proposed for Peer-to-peer (P2P) content/file sharing in mobile ad hoc networks (MANETs). In this article, we apprise a comprehensive survey of researches related to P2P overlay networks for sharing the content at the application layer in MANETs. We compare and contemplate the features, vitality, and vulnerability of these approaches and highlight indispensable research challenges that are imperative to address and will have substantial vantages. The fallout of the analysis would serve as a substantial guide for anyone willing to delve into research on the topic of P2P overlay over MANETs.

Merging of DHT-based logical networks in MANETs

We study the challenging problem of the network partitioning and merging in context with the mismatch problem and the resilience of the logical structure in distributed hash table (DHT)-based routing protocols for mobile ad hoc networks (MANETs). The existing DHT-based approaches for routing in MANETs do not consider the merging of logical networks, which occurs because of limited transmission range and mobility of nodes. In this paper, we identify that the mismatch problem is aggravated when logical networks are merged, which directly depends upon the shape of the logical structure in which nodes are arranged according to their logical identifier. To address this problem, we first propose a leader-based approach (LA) to detect and merge logical networks. In addition, we discuss the effectiveness of a three-dimensional logical space and three-dimensional logical structure when logical networks are merged. In three-dimensional logical space and three-dimensional logical structure, we take into account the physical intra-neighbour relationship of a node and interpret that relationship in terms of logical identifiers. Simulation results show that the proposed DHT-based protocol along with LA outperforms the existing DHT-based routing protocol in terms routing overhead, end-to-end delay, path-stretch values and packet delivery ratio. Copyright

Logical clusters in a DHT-Paradigm for scalable routing in MANETs

Connectivity of nodes in the logical network is the minimal requirement for the functionality of a distributed hash table (DHT)-based routing protocol. In case of high mobility, frequent changes to the network topology introduce higher maintenance overhead for updating the mapping information that worsens not only the performance of these protocols, but also restricts their pertinence only to the networks with low mobility. In addition, the route to the destination node in such protocols is not immediately available which result in high lookup latency for the requesting node.In this paper, we proposes a novel 3-dimensional logical cluster-based DHT routing protocol for mobile ad hoc network (MANETs) that use logical clustering and an effective replication strategy to reduce the routing overhead and lookup latency introduced by the above problems. Simulation results substantiate the effectiveness of the proposed protocol in terms of reducing the delay by slightly increasing the control overhead.