Abstract:
In wireless networks, conditions may change rapidly and unpredictably. Often wireless networks are not designed to adapt to these changing conditions and perform poorly when they become congested. The multi-hop broadcast nature of wireless mesh networks amplifies the problem of poor wireless performance. Mixed bias scheduling has previously been applied successfully to wireless mesh networks however, it still suffers from similar problems when conditions change rapidly. In this work we propose an adaptive mixed bias (AMB) algorithm which uses a tabu search approach to change based on delay and dropped packets in the network. The proposed scheduling approach consists of three important algorithms, namely, the tabu search algorithm, move generation, and utility function. The adaptive mixed bias approach is compared against IEEE 802.11 and the non-adaptive mixed bias approach. The performance is evaluated using the packet delivery ratio and average end-to-end delay metrics.

Here are the slides from the talk: BWCCA-NGWMN2010-final (pdf)
and here is the link to the pdf from the conference: Adaptive Mixed Bias Resource Allocation for Wireless Mesh Networks (pfd)

There were people from 40 different countries there and I feel like I met someone from almost every one of them at some point. There were over 300 people at AINA this year, which apparently is down from the last couple of years (where they had 4-500) but it was still a great conference for me. I will post my slides from my presentation in this post in case anyone is interested, along with a link to the paper once it is available. I submitted another paper last night for a conference in Toronto and am working on two more papers, so hopefully I’ll be travelling soon. I am trying to aim for ICC in South Africa next year.

Here are a few pictures from the conference.

Abstract:
This paper addresses the problem of scheduling in Wireless Mesh Networks (WMNs). The paper first discusses existing scheduling algorithms and classifies them based on the technique they use and their implementation frameworks.Then detailed discussions of the proposed scheduling method are presented. Simulation experiments are conducted to compare the performance of fair scheduling with the method that does not use fair scheduling. The simulation results confirm that the proposed scheduling method has better performance with respect to the metrics used for performance evaluation.

J.B. Ernst, M.K. Denko, “Fair Scheduling with Multiple Gateways in Wireless Mesh Networks”, in Proc. of the 22nd IEEE Int. Conf. on Advanced Information Networking and Applications (AINA 2009), Bradford UK, 2009.

The paper itself is available through IEEE Xplore

Here are some pictures from the day:

Preparing for the Defense before Everyone Arrives

Some Members of Pervasive Computing and Wireless Network (PerWin) Research Group, University of Guelph

Answering Questions from the Committee at Guelph

After some relaxing, a conference in UK and some business related projects I will finally have some time (hopefully) to update the site with all the projects, articles and source I have been slowly working on the past few months in between working like crazy on my M.Sc. This fall I start my Ph.D. which will likely at least start from the work I just worked on.

Update Ubuntu:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install libxt-dev

Download the NS-2.33 and HWMP All-in-One Package here:

Updated with new link: *

Untar the file:

Configure and Install NS2

cd ns
./configure
make
sudo make install

All ready to go. Enjoy.

The presentation gave a background on why load balancing and scheduling are important in WMNs. Additionally a survey on the current problems that I find interesting in the area was presented. In case you don’t want to get the presentation / you don’t have MS Office here are the main points from the presentation:

Why is Fair Scheduling Important in WMN:

• Starvation & Unequal Quality of Service (Qos) caused by “greedy” flows or proximity from Gateways which allow other traffic to be ignored or serviced unequally
• In commercial applications of WMNs customers pay equal amounts and expect equal service
• In many solutions that exist today, we cannot have Fairness and Throughput at the same time

Example of a Wireless Mesh Network : netdts.com

Why is Load Balancing Important in WMN:

• Multiple path redundancy is an important trait of WMN however instead of traffic being spread around the multiple links, often the same links become overused and congested while other links are barely used
• Load Balancing tries to solve this problem using at Mesh Routers, Gateways, and sometimes Links to attempt to spread the traffic around the network (although some papers claim that Load Balancing on the links isn’t effective)

Current Problems in Fair Scheduling and Load Balancing in WMN:

• Assumptions in some papers: single hop networks only, limited or no mobility (of the Mesh Routers), fixed topology (Mesh Routers cannot be added or removed and the topology is known at all times)
• Some papers assume that uplink and downlink scheduling can be treated the same when it may be beneficial to treat them independently
• Distributed Vs Centralized Scheduling & Load Balancing
• Future work on many papers cite experimentation with different metrics, optimal locations and number of gateways etc.
• Thorough investigation of load balancing at the gateways, links or mesh routers

If after all this you would still like the presentation, you can download it from the link below:

Download:

Fair Scheduling and Load Balancing in Wireless Mesh Networks by Jason Ernst. May 26th 2008.