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Abstract

Content

Introduction

Nowadays, more and more people have a mobile communication device and want to have a high speed Internet access wherever they situated. One of the means providing broadband access, as well as covering a large area is wireless mesh network.

The united standard for mesh networks is being developed currently. So the Committee IEEE 802.11s standardizes Wireless Local Area Network (WLAN) of mesh network. The standard in the future will have to be supported by the all hardware manufacturers of wireless mesh networks.

Wireless mesh networks promise greater flexibility, higher reliability and increased productivity in comparison with conventional wireless LANs.

To construct the routes among the nodes of wireless mesh network the route protocols are used. Routing protocols affect the efficiency of the network, as well as the logic of constructing routes. They must respond to dynamic changes in the network and build the best possible routes, according to the requirements and protocol applied.

1. Theme urgency

For routing in wireless mesh networks routing protocols such as Ad Hoc On Demand Distance Vector (AODV) are used, as well as Optimized Link-State Routing (OLSR), Hybrid Wireless Mesh Protocol (HWMP) etc.

Master's thesis is dedicated to the actual task of selecting a routing protocol that allows using resources of the wireless mesh network efficiently, and improves the routing system in the required routing protocol.

2. Goal and tasks of the research

The objectives of the research is to improve the efficiency of resource wireless mesh network use by the appropriate selection of a routing protocol, as well as through better routing system in the required protocol.

Tasks of the research:

  • To analyze the peculiarities of wireless mesh networks.
  • Analyze the work of routing protocols used in wireless mesh networks.
  • Perform simulation of the selected routing protocols and compare the results.
  • Select the routing protocol to further improve its system of constructing routes

The object of this research is routing principles in wireless mesh networks.

Methods of the research. Simulations of routing protocols in wireless mesh networks are used. Mathematical tools of genetic algorithms are also used to improve the routing system in the required routing protocol.

Planned scientific and technical innovation:

  • Further development of genetic algorithms for constructing routes in wireless mesh networks.
  • Development and implementation of a software algorithm for constructing a route based on genetic algorithms.

3. Review of sources

Analysis of the IEEE 802.11s standard is carried out in the publications of V.Vishnevsky, Lakontsev D., A. Safonov, S. Shpilev [1-2]. In their works the authors analyze the characteristics of the future united standard, as well as the routing protocol proposed in this standard. Also in the Multi-channel mesh-networks: approaches analysis and efficiency assess [3] the performance of multi-channel wireless mesh networking standard IEEE 802.11s is estimated. In the works of Efremov A. [4] a routing algorithm for wireless mesh networks based on virtual channels is proposed. In her work Maximova D. [5] proposes to use neural methods for routing in wireless mesh networks.

Among the foreign, especially English-language researches, there are much more papers are devoted to this subject. In IEEE 802.11S: the wlan mesh standard [6] the analysis of the future standard for wireless mesh networks is proposed. In [7] the authors propose to improve the performance of wireless mesh networks through the use of other metrics in the construction of the routing protocol Hybrid Wireless Mesh Protocol (HWMP). So instead of Airtime link metric (ALM), they offer their own metric Expected Forwarding Delay (EFD). In Improving IEEE 802.11s Wireless Mesh Networks for Reliable Routing in the Smart Grid Infrastructure [8], the authors improve the wireless mesh network standard 802.11s. They offer several mechanisms to improve network performance by improving the metrics that evaluate the effectiveness of the route.

4. Improving OLSR routing protocol

Based on the results obtained in the simulation of routing protocols AODV, OLSR and HWMP performed in [9-10] OLSR routing protocol was selected for further improvements.

It is proposed to build a route based on genetic algorithms (GA). They are based on the use of evolutionary principles to search for optimal solutions [12].

An example of chromosome (routing path) encoding from node to node is shown in Fig. 1. In this work the following genetics operators: tournament selection, one-point crossover, variable random mutation and elitism reproduction mechanism are applied.

Fig. 1. – Visualization of routing path and its encoding scheme

Fig. 1 – Visualization of routing path and its encoding scheme
(animation: 11 frames, delay 0,5 s, repeat forever, size 15 Kbyte, Easy GIF Animator)

Conclusion

Wireless mesh networks are a promising area of urban access networks, as well as it is useful for the deployment of temporary low-cost access networks.

Master's thesis is devoted to the urgency of the problem of selecting a routing protocol for wireless mesh networks, as well as to improvements of the route constructing system of required routing protocol. During the research:

  • The features of wireless mesh networks were analyzed.
  • Modeling and comparing the effectiveness of the following routing protocols: AODV, OLSR, HWMP were carried out.
  • The OLSR routing protocol has been chosen as the most perspective for further improvements.
  • The algorithm that constructs the most appropriate path using genetic routing algorithm was proposed.

Further studies are focused on the following aspects:

  • To imply software application of the proposed algorithm for the OLSR protocol in the simulation environment.
  • To compare the results of the proposed modified protocol and standard OLSR protocol.
  • To make recommendations regarding the effectiveness of the proposed modifications of OLSR in wireless mesh networks.

References
  1. Вишневский В., Лаконцев Д., Сафонов А., Шпилев С. Маршрутизация в широкополосных беспроводных mesh-сетях стандарта IEEE 802.11s // ЭЛЕКТРОНИКА: Наука, Технология, Бизнес. – 2008. – c. 64-69.
  2. Вишневский В., Лаконцев Д., Сафонов А., Шпилев С. Mesh-сети стандарта IEEE 802.11s – технологии и реализация // ЭЛЕКТРОНИКА: Наука, Технология, Бизнес. – 2008. – c. 98-105.
  3. Ляхов А.И., Пустогаров И.А., Шпилев С.А. Многоканальные mesh-сети: анализ подходов и оценка производительности // Информационные процессы. – 2008. Том 8, № 3. – с. 173–192.
  4. Ефремов А.Ю. Использование в mesh сетях стандарта IEEE 802.11 алгоритмов маршрутизации на основе виртуальных каналов // Технические и программные средства систем управления, контроля и измерения. – Москва, октябрь 2010. – с. 1-6.
  5. Максимов Д.Ю. Нейронный метод коммутации в беспроводных сетях передачи данных с подвижными объектами // Технические и программные средства систем управления, контроля и измерения. – Москва, октябрь 2010. – с. 829-834.
  6. Guido R. Hiertz, Dee Denteneer, Sebastian Max, Rakesh Taori. IEEE 802.11S: the wlan mesh standard // IEEE Wireless Communications. – February 2010. – pp. 104-111.
  7. Md. Shariful Islam, Muhammad Mahbub, M. Abdul Hamid, Choong Seon Hong. High throughput path selection for IEEE 802.11s based Wireless Mesh Networks // Computer communication networks: network protocols. – Kprea. – 2010.
  8. Ji-Sun Jung, Keun-Woo Lim, Jae-Beom Kim, Young-Bae Ko. Improving IEEE 802.11s Wireless Mesh Networks for Reliable Routing in the Smart Grid Infrastructure // Science and Technology. – 2010.
  9. Чабанный А.А. Сравнение протоколов маршрутизации беспроводных mesh сетей // Сучасні проблеми радіотехніки та телекомунікацій «РТ - 2012»: Матеріали 8-ої міжнар. молодіжної наук.-техн. конф., Севастополь 23 — 27 квітня 2012 р. / М-во освіти і науки, молоді та спорту України, Севастоп. нац. техн. ун-т; наук. ред. Ю.Б.Гімпілевич. — Севастополь: СевНТУ, 2012.
  10. Чабанный А.А. Дослідження роботи протоколів маршрутизації у бездротових mesh мережах // Тези всеукраїнського конкурсу студентських наукових робіт з технічних наук у 2011/2012 роках ("Телекомунікаційні системи та мережі", "Інформаційні мережі зв'язку"). - Одеса: ВМВ, 2012.
  11. Стандарт протокола OLSR [Электронный ресурс]. – Режим доступа: http://www.ietf.org/rfc/rfc3626.txt
  12. Luke S. Essentials of Metaheuristics. // A Set of Undergraduate Lecture Notes [Электронный ресурс]. September, 2009 – 237.

Important note

This master's work has not been completed yet. Final completion: December 2012. The full version of the work and materials on the topic can be obtained from the author or his scientific supervisor after this date.