A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan

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Design and analysis of a beacon-less routing protocol for large volume content dissemination in vehicular ad hoc networks

Largevolumecontentdisseminationispursuedbythegrowingnumberofhighquality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well

Medium Access Control Protocols for Ad-Hoc Wireless Networks: A Survey

Studies of ad hoc wireless networks are a relatively new field gaining more popularity for various new applications. In these networks, the Medium Access Control (MAC) protocols are responsible for coordinating the access from active nodes. These protocols are of significant importance since the wireless communication channel is inherently prone to errors and unique problems such as the hidden-terminal problem, the exposed-terminal problem, and signal fading effects. Although a lot of research has been conducted on MAC protocols, the various issues involved have mostly been presented in isolation of each other. We therefore make an attempt to present a comprehensive survey of major schemes, integrating various related issues and challenges with a view to providing a big-picture outlook to this vast area. We present a classification of MAC protocols and their brief description, based on their operating principles and underlying features. In conclusion, we present a brief summary of key ideas and a general direction for future work

A COMMUNICATION FRAMEWORK FOR MULTIHOP WIRELESS ACCESS AND SENSOR NETWORKS: ANYCAST ROUTING & SIMULATION TOOLS

The reliance on wireless networks has grown tremendously within a number of varied application domains, prompting an evolution towards the use of heterogeneous multihop network architectures. We propose and analyze two communication frameworks for such networks. A first framework is designed for communications within multihop wireless access networks. The framework supports dynamic algorithms for locating access points using anycast routing with multiple metrics and balancing network load. The evaluation shows significant performance improvement over traditional solutions. A second framework is designed for communication within sensor networks and includes lightweight versions of our algorithms to fit the limitations of sensor networks. Analysis shows that this stripped down version can work almost equally well if tailored to the needs of a sensor network. We have also developed an extensive simulation environment using NS-2 to test realistic situations for the evaluations of our work. Our tools support analysis of realistic scenarios including the spreading of a forest fire within an area, and can easily be ported to other simulation software. Lastly, we us our algorithms and simulation environment to investigate sink movements optimization within sensor networks. Based on these results, we propose strategies, to be addressed in follow-on work, for building topology maps and finding optimal data collection points. Altogether, the communication framework and realistic simulation tools provide a complete communication and evaluation solution for access and sensor networks

Improving the Performance of Medium Access Control Protocols for Mobile Adhoc Network with Smart Antennas

Requirements for high quality links and great demand for high throughput in Wireless LAN especially Mobile Ad-hoc Network has motivated new enhancements and work in Wireless communications such as Smart Antenna Systems. Smart (adaptive) Antennas enable spatial reuse, increase throughput and they increase the communication range because of the increase directivity of the antenna array. These enhancements quantified for the physical layer may not be efficiently utilized, unless the Media Access Control (MAC) layer is designed accordingly. This thesis implements the behaviours of two MAC protocols, ANMAC and MMAC protocols in OPNET simulator. This method is known as the Physical-MAC layer simulation model. The entire physical layer is written in MATLAB, and MATLAB is integrated into OPNET to perform the necessary stochastic physical layer simulations. The aim is to investigate the performance improvement in throughput and delay of the selected MAC Protocols when using Smart Antennas in a mobile environment. Analytical methods were used to analyze the average throughput and delay performance of the selected MAC Protocols with Adaptive Antenna Arrays in MANET when using spatial diversity. Comparison study has been done between the MAC protocols when using Switched beam antenna and when using the proposed scheme. It has been concluded that the throughput and delay performance of the selected protocols have been improved by the use of Adaptive Antenna Arrays. The throughput and delay performance of ANMAC-SW and ANMAC-AA protocols was evaluated in details against regular Omni 802.11 stations. Our results promise significantly enhancement over Omni 802.11, with a throughput of 25% for ANMAC-SW and 90% for ANMC-AA. ANMAC-AA outperforms ANMAC-SW protocol by 60%. Simulation experiments indicate that by using the proposed scheme with 4 Adaptive Antenna Array per a node, the average throughput in the network can be improved up to 2 to 2.5 times over that obtained by using Switched beam Antennas. The proposed scheme improves the performances of both ANMAC and MMAC protocols but ANMAC outperforms MMAC by 30%

HWN* Mobility Management Considering QoS, Optimisation and Cross Layer Issues

In this paper, we address mobility management for 4th generation heterogeneous networks from a quality of service (QoS), optimisation and cross layer design perspective. Users are classified as high profile, normal profile and low profile according to their differentiated service requirements. Congestion avoidance control and adaptive handover mechanisms are implemented for efficient cooperation within the mobile heterogeneous network environment consisting of a TDMA network, ad hoc network and relay nodes. A previous proposed routing algorithm is also revised to include mobility management