1. Dynamic Load Balancing and Channel Allocation in Indoor WLAN
Mohamad Haidar
Committee : Dr. Hussain Al-Rizzo
Dr. Robert Akl
Dr. Haydar Al-Shukri
Dr. Yupo Chan
Dr. Hassan Elsalloukh
Dr. Seshadri Mohan

2. Dissertation Proposal
Proposal Outline
Background
Problem Statement
Review of Literature
Research Objectives
Project Plan
Conclusion
References
Questions
9/20/2018
Dissertation Proposal

3. Dissertation Proposal
Background
What is WLAN?
Flexible data communications system
Consists of one or more wireless devices
WLAN uses IEEE standard
Two types of WLAN:
Ad-Hoc: Two or more PCs equipped with wireless adapter cards, NO connection to a wired network.
Client/Server: Multiple wireless devices linked to a central hub (AP) which act as a bridge to the network resources.
9/20/2018
Dissertation Proposal

4. Background(continued)
Family of WLAN:
802.11: 1-2 Mbps in the 2.4 GHz band (FHSS or DSSS)
802.11a: Extension to provides up to 54 Mbps in the 5 GHz band (OFDM)
802.11b (Wi-Fi): extension of provides 11 Mbps with a fall back to 5.5, 2, and 1 Mbps in the 2.4 GHz. (DSSS)
802.11g: offers transmission of Mbps over relatively short distances in the 2.4 GHz.(OFDM)
802.11n: build on MIMO offers high throughput of Mbps
9/20/2018
Dissertation Proposal

5. Dissertation Proposal
Problem Statement
Dynamically balance traffic load on APs and minimize channel interferences by assigning optimal channels (non-overlapping) to the APs on an indoor WLAN.
Interferences:
Co-channel
Adjacent
9/20/2018
Dissertation Proposal

6. Dissertation Proposal
Literature Review
Cellular networks review:
ILP optimization was used on selecting optimal position of BSs in a cellular network [1].
Divide and conquer is another optimization technique was used to position BSs [2].
Dynamic load balancing (channels) was applied in cellular networks to reduce call blocking probability [3].
WLAN review:
Static
AP placement and channel assignment was proposed in [4] and [5] using an optimal ILP.
Provides best set of AP locations for load balancing
Constant BW is provided by a channel at an AP regardless of the number of users
9/20/2018
Dissertation Proposal

7. Literature Review (continued)
WLAN review:
Dynamic
Dynamic load balancing was ONLY considered by [8]. But did NOT provide reconfiguration of channels.
Only proposed an approach to minimize traffic disruption caused by association or dissociation of new nodes to and from their respective APs.
Other related work:
Moving objects, such as people affect the performance of the system by introducing large variations in the received signal strength [9].
9/20/2018
Dissertation Proposal

8. Literature Review (continued)
Other Related work:
Without proper consideration of cell locations and cell sizes, deployment of high-density WLANS might carry significant risk of poor performance.
WHY?
9/20/2018
Dissertation Proposal

9. Dissertation Proposal
Research Objectives
Optimize AP selection and traffic allocation
Formulate AP placement according to initial traffic
Optimize dynamic channel allocation
Formulate a dynamic optimal channel assignment by min. interference between adjacent and co-channel APs.
9/20/2018
Dissertation Proposal

10. Research Objectives (continued)
Interference by adjacent and co-channel cells should be minimized.
A node is considered to be covered by an AP if power received from its corresponding AP exceeds a certain threshold value.
User distribution traffic load will be treated as a statistical Poisson distribution (varying traffic with time).
Propagation mechanisms will be taken into consideration:
For optimal performance of the whole network, a centralized decision-making algorithm will be implemented.
9/20/2018
Dissertation Proposal

11. Research Objective (continued)
Formulation
Objective:
Minimize congestion at bottleneck APs:
max{C1, C2, …, CM}, (1)
Where i is the number of APs, j is the number of candidate APs and Ci is the congestion factor at AP i.
The objective function is subject to the following constraints
(2)
Where xij is a binary variable takes the value of 1 when demand cluster i is assigned to AP j and 0 otherwise.
for j=1,…,M (3)
Where Bj is the maximum bandwidth of AP j, Ti is the average traffic load at demand cluster i.
Dynamic feature will add the time constraint on these equations!
9/20/2018
Dissertation Proposal

12. Dissertation Proposal
Project Plan
Phase I:
Has been started and in progress
Some simulations have been conducted using available software packages
Optimization and Network flow class with Dr. Yupo Chan
Realistic indoor environments will aid in formulating optimization problem
Indoor floor plan using different wall materials, door way and Tx.
9/20/2018
Dissertation Proposal

13. Project Plan (continued)
Phase II:
Formulating the optimization problem
Apply the formulated problem to realistic environments
Phase III:
Dynamic optimization feature will be added.
Mobility model will be presented in terms of Poisson distribution
Several simulations will be carried out under different scenarios and constraints.
Results will be presented and compared to models reported in [4] and [5].
9/20/2018
Dissertation Proposal

14. Dissertation Proposal
Conclusion
It is expected that the proposed dynamic traffic load-balancing scheme will lead to an effective utilization of the channel and an improvement in capacity and coverage area of WLAN.
Unlike other schemes this dynamic feature will strive to give the optimal performance as time progresses.
9/20/2018
Dissertation Proposal

15. Dissertation Proposal
References
C. Glaber, S. Reith, and H. Vollmer. “The Complexity of Base Station positioning in Cellular Networks.” Workshop on Approximation and Randomized Algorithm in Communications Networks, March 2000.
E. Yammaz and O. K. Tonguz. “Dynamic Load Balancing Performance in Cellular Networks with Multiple Traffic Types.” IEEE Vehicular Technology Conference, pages , September 2004
S. Gordon and A. Dadej. “Design of High Capacity Wireless LANs based on b Technology.” 6th International Symposium on Communications Interworking, pages , October 13-16, 2002.
R. Akl and S. Park. “Optimal Access Point selection and Traffic Allocation in IEEE Networks,” Proceedings of 9th World Multiconference on Systemics, Cybernetics and Informatics (WMSCI 2005): Communication and Network Systems, Technologies and Applications, paper no. S464ID, July 2005
Y. Lee, K. Kim, and Y. Choi. Optimization of AP placement and channel assignment in wireless LANs. LCN th Annual IEEE Conference on Local Computer Networks, pages , November 2002.
M. Klepal, R. Mathur, A. McGibney, and D. Pesch. “Influence of People Shadowing on Optimal Deployment of WLAN Access Points.” IEEE Vehicular Technology Conference, pages , 2004.
9/20/2018
Dissertation Proposal

16. Dissertation Proposal
Questions?
9/20/2018
Dissertation Proposal