Rashid Hafeez Khokhar

A Review on Distributed Application Processing Frameworks in Smart Mobile Devices for Mobile Cloud Computing

The latest developments in mobile devices technology have made smartphones as the future computing and service access devices. Users expect to run computational intensive applications on Smart Mobile Devices (SMDs) in the same way as powerful stationary computers. However in spite of all the advancements in recent years, SMDs are still low potential computing devices, which are constrained by CPU potentials, memory capacity and battery life time. Mobile Cloud Computing (MCC) is the latest practical solution for alleviating this incapacitation by extending the services and resources of computational clouds to SMDs on demand basis. In MCC, application offloading is ascertained as a software level solution for augmenting application processing capabilities of SMDs. The current offloading algorithms offload computational intensive applications to remote servers by employing different cloud models. A challenging aspect of such algorithms is the establishment of distributed application processing platform at runtime which requires additional computing resources on SMDs. This paper reviews existing Distributed Application Processing Frameworks (DAPFs) for SMDs in MCC domain. The objective is to highlight issues and challenges to existing DAPFs in developing, implementing, and executing computational intensive mobile applications within MCC domain. It proposes thematic taxonomy of current DAPFs, reviews current offloading frameworks by using thematic taxonomy and analyzes the implications and critical aspects of current offloading frameworks. Further, it investigates commonalities and deviations in such frameworks on the basis significant parameters such as offloading scope, migration granularity, partitioning approach, and migration pattern. Finally, we put forward open research issues in distributed application processing for MCC that remain to be addressed.

A fuzzy logic approach to beaconing for vehicular ad hoc networks

Vehicular Ad Hoc Network (VANET) is an emerging field of technology that allows vehicles to communicate together in the absence of fixed infrastructure. The basic premise of VANET is that in order for a vehicle detect other vehicles in the vicinity. This cognizance, awareness of other vehicles, can be achieved through beaconing. In the near future, many VANET applications will rely on beaconing to enhance information sharing. Further, the uneven distribution of vehicles, ranging from dense rush hour traffic to sparse late night volumes creates a pressing need for an adaptive beaconing rate control mechanism to enable a compromise between network load and precise awareness between vehicles. To this end, we propose an intelligent Adaptive Beaconing Rate (ABR) approach based on fuzzy logic to control the frequency of beaconing by taking traffic characteristics into consideration. The proposed ABR considers the percentage of vehicles traveling in the same direction, and status of vehicles as inputs of the fuzzy decision making system, in order to tune the beaconing rate according to the vehicular traffic characteristics. To achieve a fair comparison with fixed beaconing schemes, we have implemented ABR approach in JIST/SWANs. Our simulation shows that the proposed ABR approach is able to improve channel load due to beaconing, improve cooperative awareness between vehicles and reduce average packet delay in lossy/lossless urban vehicular scenarios.

Intelligent beaconless geographical forwarding for urban vehicular environments

A Vehicular Ad hoc Network is a type of wireless ad hoc network that facilitates ubiquitous connectivity between vehicles in the absence of fixed infrastructure. Source based geographical routing has been proven to perform well in unstable vehicular networks. However, these routing protocols leverage beacon messages to update the positional information of all direct neighbour nodes. As a result, high channel congestion or problems with outdated neighbour lists may occur. To this end, we propose a street-aware, Intelligent Beaconless (IB) geographical forwarding protocol based on modified 802.11 Request To Send (RTS)/ Clear To Send frames, for urban vehicular networks. That is, at the intersection, each candidate junction node leverage digital road maps as well as distance to destination, power signal strength of the RTS frame and direction routing metrics to determine if it should elect itself as a next relay node. For packet forwarding between Intersections, on the other hand, the candidate node considers the relative direction to the packet carrier node and power signal strength of the RTS frame as routing metrics to elect itself based on intelligently combined metrics. After designing the IB protocol, we implemented it and compared it with standard protocols. The simulation results show that the proposed protocol can improve average delay and successful packet delivery ratio in realistic wireless channel conditions and urban vehicular scenarios.

A taxonomy of cross layer routing metrics for wireless mesh networks

Multi-hop, multi-channel, and multi-radio wireless mesh networks (WMNs) are emerging as promising field of wireless technology with self-organizing and self-healing features for internet and real time applications, i.e., VoIP and Video over IP. Interoperability feature of WMNs have made them to integrate easily with other network technologies like wired networks, WiFi, WiMax, MANETs, and cellular networks. WMNs are gaining popularity due to their high network throughput which highly depends on the routing procedures. Routing algorithms like optimized link state routing protocol and dynamic source routing make efficient routing decisions on the basis of routing metrics which actually predict the cost of link quality. Most of the routing protocols and routing metrics implemented in WMNs are actually designed for mobile ad hoc networks (MANETs). Since WMNs have different characteristics and limitations as compared to MANETs, so the routing metrics design for MANETs do not perform well in WMNs. Furthermore, quality of service (QoS) and throughput of the network in WMNs can be enhanced by using cross layer routing approach and by deploying multi-channel multi-radio (MCMR) scenarios in each relay node. This article discusses a design taxonomy, limitations and qualitative comparison of existing routing metrics for QoS in MCMR WMNs with respect to routing parameters, i.e., transmission rate, inter-flow interference, intra-flow interference, congestion, and channel diversity. Moreover, our taxonomy also opens the door up for new research areas in the design of cross layer routing metrics for MCMR radio WMNs for high throughput IP connectivity.

Fuzzy-assisted social-based routing for urban vehicular environments

In the autonomous environment of Vehicular Ad hoc NETwork (VANET), vehicles randomly move with high speed and rely on each other for successful data transmission process. The routing can be difficult or impossible to predict in such intermittent vehicles connectivity and highly dynamic topology. The existing routing solutions do not consider the knowledge that behaviour patterns exist in real-time urban vehicular networks. In this article, we propose a fuzzy-assisted social-based routing (FAST) protocol that takes the advantage of social behaviour of humans on the road to make optimal and secure routing decisions. FAST uses prior global knowledge of real-time vehicular traffic for packet routing from the source to the destination. In FAST, fuzzy inference system leverages friendship mechanism to make critical decisions at intersections which is based on prior global knowledge of real-time vehicular traffic information. The simulation results in urban vehicular environment for with and without obstacles scenario show that the FAST performs best in terms of packet delivery ratio with upto 32% increase, average delay 80% decrease, and hops count 50% decrease compared to the state of the art VANET routing solutions.

An Extendable Simulation Framework for Modeling Application Processing Potentials of Smart Mobile Devices for Mobile Cloud Computing

The recent efforts in Mobile Cloud Computing (MCC) focus on defining novel methods, policies and mechanisms for efficiently leveraging the services of cloud data centers for mitigating resources constraints in mobile devices. To test these newly developed methods and policies, researchers need tools for evaluating the hypothesis prior to deployment on the real time system. Simulation based approaches in evaluating the deployment mechanism for accessing distributed services and application behaviors offer significant benefits, as they allow mobile application developers to test performance of the operational logic of distributed deployment in a repeatable and controllable environment free of cost and to tune the performance bottlenecks before real world deployment on commercial MCC environment. This paper presents SmartSim, which is a simulation toolkit developed for modeling the application processing capabilities of Smart Mobile Devices (SMDs). SmartSim simulates the system and behavior modeling of mobile devices. The toolkit provides an easy to configure simulation environment for modeling application processing attributes of SMD and arbitrary resources intensive mobile application. SmartSim models the mechanism of runtime partitioning of elastic mobile application and determines resources utilization on SMDs during the execution of the elastic application.

Towards lightweight distributed applications for mobile cloud computing

The lightness of distributed application processing platform becomes more imperative with rapid proliferation of SMDs and ever increasing demand to utilize SMDs for intensive applications. Lightweight framework aspires for minimum possible overhead and optimal possible resources utilization on SMDs. Traditionally the distributed platform is established at runtime by outsourcing intensive applications partially or entirely to cloud datacenters. Such approaches implant intensive responsibilities of distributed platform establishment and management on SMDs for the entire duration of remote application processing. For that reason computing resources of SMDs are exploited copiously. In this paper we investigate the heavyweight aspects of current offloading algorithms in two different scenarios. First, we analyze the impact of VM deployment for application offloading in simulation environment using CloudSim. Second, we investigate the heavyweight aspects of current offloading algorithms by qualitative analysis. Finally, we propose a novel model for lightweight distributed application deployment in mobile cloud computing.

Using VANET to support green vehicle communications for urban operation rescue

The paper presents a model of operation rescue and group vehicle approach to support green vehicle communication for urban operation rescue. Using vehicular technology could benefit operation rescue vehicles by enabling each vehicle spreads the information related before arriving at the incident place. In an effort to understand the operation rescue activities, studies on the case study are briefly discussed. Green vehicle communications requirements are presented to show the significance of using vehicular technology. Experiments using NS-2 to measure the average delay time per trip and average throughput for three different scenarios are presented.

On QoS routing in Mobile WiMAX cognitive radio networks

Throughput maximization is one of the main challenges in cognitive radio ad hoc networks, where the availability of local spectrum resources may change from time to time and hop by hop. Technologies based on 802.16e which called Mobile WiMAX (Worldwide Interoperability Microwave Access) promises to deliver high data rates over large distances and deliver multimedia services and are expected to play a major role in high speed broadband delivery. The maximum allowed number of hops must be carefully considered because higher number of hops will increase the transmission time and degrades the throughput and end to end delay. Multi-hop based network may also improve the system performance by using cooperative relay technique. There are various challenges for the routing in WiMAX mesh such as delay, long transmission scheduling, and increasingly stringent Quality of Service (QoS) support and load balance and fairness limitations. In this paper we use cognitive radio network composed of wireless devices able to opportunistically access the shred radio resource. The core of such networking paradigm is the capability of cognitive radio to monitor spectrum occupation to exploit spectrums holes for transition. Extensive simulations are conducted under MATLAB and compare the performance of our routing protocol with AODV for Mobile WiMAX environment. The propose algorithm shows high throughput, reduce end to end delay, and increase packet delivery ratio.

Handover Latency Measurement of Mobile IPv6 in a Testbed Environment

The emergence of wireless networking necessitates continuous time connectivity to support end-to-end TCP or UDP sessions. Wireless networking does not provide reliable connections to mobile users for real-time traffic such as voice over IP, audio streaming and video streaming. Handover latency in Mobile IPv6 poses many challenges to the research world in terms of disconnecting users while roaming. Many efforts have been made to reduce the handover latency with focus either on layer 2 or layer 3. This paper presents the handover procedure of Mobile IPv6 and investigates various factors affecting the delay during network switch over. In this paper, a testbed environment is presented that includes two different wireless LAN networks using Universal Mobile IP for Linux (UMIP) implementation and Cisco routers. The aim is to present handover latency caused by multiple signals at layer 2 and layer 3 and make recommendations on how to reduce the total handover latency experienced by the MIPv6 protocol.