Routing Protocol For Mesh Cognitive Radio Networks Computer Science Essay

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Communication protocols which regulate the communication between computers are set of formal rules that govern the exchange of information. Communication activity fails if the protocol is not followed.

Wireless Networks (WNs) are experiencing bandwidth scarcity and it is controlled by introducing cognitive radios and multipath routing. Multipath Routing and Spectrum Access (MRSA) is the only available multipath routing protocol for MCRNs. It is on-demand and uses minimum hop count for selecting multiple paths between source and destination pair. But it does not consider the dynamics of Cognitive Radios (CRs) while selecting the paths. Thus paths selected by this routing protocol are not reliable. And the most important aspect to be considered in Cognitive Radio Networks (CRNs) is reliability and efficiently utilization of available spectrum band.

1. 1 Project Title


1.2 Introduction and Background

Wireless Networks (WNs) is a popular access technology of the present age. It is all about great support of user preferences but still needs improvements. The main issue that needs to be solved on primary bases is its static spectrum management. Static spectrum management will result in the wastage of bandwidth.

To resolve the above mentioned issue, a novel communication paradigm 'Cognitive Radio' is proposed. It minimizes the wastage of radio spectrum band by using the band efficiently and allowing the licensed and un-licensed user to use the channel when it is free.

1.3 Problem Statement

Existing routing proposals for Mesh Cognitive Radio Networks (MCRNs) are not considering the dynamics of CRNs due to which bandwidth of the available spectrum is wasted and reliability need improvements. This research will produce an on-demand multipath routing protocol that resolves this issue by considering the true dynamic nature of CRNs.

1.4 Previous Work

In the last few years, researchers are trying to explore new ways to deploy CRNs networks, while in advancement in Mobile Ad hoc Networks (MANETs) and wireless mesh networks motivated them but problem is the routing protocols for these scenarios cannot directly apply on CRNs because they are not dynamic in nature.

Split Multipath Routing (SMR) is on demand multipath routing protocol for MANETs. It discovers multiple disjoint paths between source and destination pair and split the data traffic on multiple established paths. SMR selects the best route based on the minimum hope count. Furthermore it considers only single channel and node level disjointness while studies show that spectrum wise disjointness is more common in CRNs equipped with multiple interfaces.

Multi-Flow Real-Time Transport Protocol (MRTP) is another multipath routing protocol for mesh-based MANETs. MRTP is based on the Real Time Protocol (RTP) and specifically used for multicast application.

Multi-Radio Link-Quality Source Routing (MR-LQSR) is multi-radio single path routing protocol for mesh-based Mobile Ad-hoc Networks (MANETs). It uses link-state protocol for selecting the best path for source destination pair. Weighted Cumulative Expected Transmission Time (WCETT) is used for path selection. WCETT consider both link quality and minimum hope count.

Multipath Routing and Spectrum Access (MRSA) is the only available multipath routing protocol for MCRNs. It is on demand and uses minimum hop count for selecting multiple paths between source and destination pair. It handles the PU appearance on any path with the help of multiple paths used for same source destination pair. It does not consider the dynamics of CRNs while selecting the paths. Thus path selected by this routing protocol are not reliable while to ensure reliability is more important in CRNs then wired or other wireless networks.

1.5 Objectives of the Project

Objectives of project are:

? To develop an efficient on-demand multipath routing protocol for MCRNs within six months

? To understand the behavior of cognitive radio networks for multipath routing

? To design and model routing protocol by using some modeling tool

? To code the proposed protocol by using some programming language

? To Simulate the proposed protocol in Network Simulator-II

? To Produce a productive outcome from the research in wireless ad-hoc networks

1.6 Specific Project Goals

The goal of project is to produce a multipath routing protocol for mesh cognitive radio networks which maximizes the bandwidth utilization and increase the reliability of network.

1.7 Scope of the Project (Abstract)

The purpose of this project is to enhance the current on-demand multipath routing protocol. A complete analysis is done to determine the most appropriate model for protocol which will be further designed and simulated. The product of this project will assist the researchers in the field of cognitive radio network to improve technology and provide a solution to communication companies to use it for multipath routing.

1.8 Glossary

WNs: Wireless Networks

WMNs: Wireless Mesh Networks

CR: Cognitive Radio

CRNs: Cognitive Radio Networks

MCRNs: Mesh Cognitive Radio Networks

MANETs: Mobile Ad-hoc Networks

SMR: Split Multipath Routing

MRTP: Multi-Flow Real-Time Transport Protocol

RTP: Real Time Protocol

MR-LQSR: Multi-Radio Link-Quality Source Routing

WCETT: Weighted Cumulative Expected Transmission Time

MRSA: Multipath Routing and Spectrum Access

MRMCRN: Multipath Routing Protocol for Mesh Cognitive Radio Networks

2. Benefits of the Project

This is research based project which can be very beneficial to two sorts of audiences. First is an academic institution and second is a communication industry.

2.1 Direct Customers / Beneficiaries of the Project

In academic institution, it gives the opportunity to students to make their knowledge rich in its domain as well as challenge them to propose something new and model their concept and further code it and simulate it. At the end, they will get results which provide the base to make a good comparison of their proposed technique with others. As a result, it promotes the culture of research and development in academic institutions. In communication industry, it provides a solution the current problem of wireless networks which is bandwidth scarcity. This solution can be more productive than the already existing ones.

2.2 Outputs Expected from the Project

Final outcome of project is a multipath routing protocol for mesh cognitive radio networks which can be used for multipath routing in any mesh cognitive radio networks to enhance the throughput and reliability of network.

3. Project Description

Wireless communication is a popular access technology due to user preferences, full time access, flexibility, mobility and reduced costs. Since wireless has no standard finalize yet, there are many areas in which research and development is in progress. Mesh Cognitive Radio Networks is one of them. In this case, wireless mesh networks have been facing inadequacy in case of bandwidth due to static channel allocation scheme which allows only licensed users to access channels and does not permit un-licensed users to access the channels although the channels are idle or not fully utilized which leads to the wastage of spectrum resources.

A novel approach, Cognitive Radio Networks is proposed which based on cognitive radios and try to solve the issue of bandwidth scarcity. But, up to now, all proposals in this context treat the wireless networks in very traditional way which does not consider the intelligent nature of cognitive radios. Proposed routing protocol for mesh cognitive radio networks will fully utilize the available spectrum and will be in accordance with nature of cognitive radios. Firstly, we will outline our constraints and draw a rough layout of whole architecture of our protocol. Then we model our proposed protocol, and then we will develop it in C++. In designing and development, we repeat this step again and again until we got our expected results and results will be evaluated on the bases of simulations in Network Simulator-II (NS-II). After simulation success, our protocol will be ready to embed in the wireless devices of mesh networks to facilitate the customers.

3.1 Functional Specification

Functional specification involves the basic functionalities performed by proposed protocol. It support for networks and services for MCRNs. It also includes the restrictions or constraints that are to be applied on our proposed protocol.

3.1.1 Functions Performed

A core functionality of a multipath protocol is providing multiple paths from source to destination. To achieve this, our proposed protocol will work in two phases.

? Route Discovery

? Route Maintenance

First is route discovery and second is route maintenance. In route discovery, protocol will discover multiple routes for source and destination pair. This route discovery will be based on those parameters which cares the nature of CRNs. In route maintenance, it will maintain a route for successful transmission of data. It will also care for the errors when some link break down occurs. It will also control the flow to packets and overhead on links.

3.1.2 Limitations and Restrictions

In designing protocol for wireless networks, security and scalability are issues which are hard to fix. Due to the wireless and mobile nature of networks, neighbors are not always trust worthy. So, it can be a big issue. Scalability is another tradeoff, which can become an issue to minimize the performance of routing protocol.

3.1.3 Application Architecture

Our proposed protocol is a multipath routing protocol which resides on network layer in OSI Reference Model.

Our protocol is a multipath routing protocol so it will work on network layer. Main reason of this protocol is its support for heterogeneous networks support. On network layer, it will support both type of network, standard IP routing network and wireless ad-hoc networks.

MRMCRN main components are Route Discovery and Route Maintenance. Before the starting of transmission it discovers the route. In route discovery, it sends route request (RREQ) to neighbors. If neighbor is destination for that request it sends route reply (RREP) back to source. Otherwise, it broadcast the route request to its neighbors until the destination is not accessed. On finding destination, a route reply (RREP) message is returned back to source which contains the source route. In this way, multiple routes are stored. And after that transmission of packets start sending. In case of some links breakdown, an error message (RERR) is sent to source node for make a decision to choose the alternative source route for transmission.

3.1.4 Equipment Configuration

This is not a software application which requires any specific software or hardware configuration settings. Routinely wireless devices can accommodate the proposed routing protocol.

3.1.5 Implementation Tools and Technology

In the designing and development of this protocol we will use following tools and technologies:


C++ is used to write kernel part of the protocol. An object oriented approach is utilized to code the protocol. It is used because it is near to hardware and can run very rapidly on hardware as compared to other high level languages.

Microsoft Visual Studio 2008

Microsoft Visual Studio 2008 is used to implement our concept in C++. This is used because it is easy to code, debug, and run in this platform.


OTcl is an object oriented tool command language which is used to build infrastructure is case of networks. Since, our project is designing of protocol for mesh cognitive networks thus it will used mostly for topology construction and scenario construction for simulations. It is used because it is easy to code and configure.

Network Simulator-II

Network Simulator-II is a simulation tool for networks. All the simulation to test our protocol will be done in NS-II. For producing the results to compare our protocol with others performance or to evaluate our protocol we can use different parts of NS-II to plot the information in the form of 2D or 3D graphs for better understanding of reader.

Linux (Fedora)

Linux is used because it will give us a better control in case of running our process and better results to our simulations. Further it is fully command based, which give user full control.

3.2 Implementation Plan

Implementation plan consider the whole implementation plan which involves the milestones and deliverables and a project schedule.