دانلود رایگان مقاله تخصیص کانال مبتنی بر بیکن و کاهش مسدود برای MANET با رابط و کانال های متعدد

Abstract

The capability of accessing multiple channels through multiple interfaces improve network capacity and is desirable for future Mobile Ad-Hoc Networks (MANETs). However, due to the presence of jammers as well as mobility and ad-hoc features, MANETs require distributed and efficient resource management for channel assignment. To address the channel assignment problem, which is a non-deterministic polynomial-time hard (NP-hard) problem, we propose a heuristic algorithm called Channel Assignment and JAmmer Mitigation (CA-JAM). The CA-JAM algorithm assigns a distinct channel for every interface of one station, and then all stations exchange the assignment information through beacon frames on every individual interface. When one station receives a beacon, the station organizes the information into tables. Therefore, each station, distributively, uses the table to reduce the number of neighboring stations using the same channel to avoid interference which in turn improves the throughput. The tables are also used to learn the disconnected neighbors due to jamming so as to mitigate the effect of jamming and maintain connectivity. CA-JAM is fully distributed with no use of control channel or central entity; thus, it improves connectivity and reduces interference by balancing stations over the available channels while mitigating jamming effects from multi channel multi interface MANETs. We confirm that CA-JAM outperforms existing protocols using the OPNET simulator.

6. Conclusion

MANETs can be easily deployed to provide essential help in a military and disaster relief networks. However, the presence of jammers, harsh environment of war zone or the absence of central entity, such as access point, affect the performance of such networks. The performance of MANETs can be enhanced by deploying stations with multiple interfaces that operate on multiple channels. While the network benefits from multiple interfaces, it still had limitations due to poor channel utilization. To overcome this issue, we proposed CA-JAM algorithm, which is a channel assignment scheme that considers jammer mitigation as well. Our simulation results showed that CA-JAM provided higher throughput with reasonable delay and re-transmission. The results confirmed that the proposed algorithm could greatly enhance the network performance; thus making MANETs feasible to use in any desired environment. Although our focus has been channel assignment and current routing protocols are designed for single interfaced MANETS, there is a room to enhance the performance by jointly integrating it with a routing protocol. Our future work will integrate channel assignment with routing to achieve a better performance and fully utilize MIMC feature. Also, we plan to implement our work with off the shelf 802.11 products, to test the performance of CA-JAM in the real environments.