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

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

Dissertation Proposal Background What is WLAN? Flexible data communications system Consists of one or more wireless devices WLAN uses IEEE 802.11 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

Background(continued) Family of WLAN: 802.11: 1-2 Mbps in the 2.4 GHz band (FHSS or DSSS) 802.11a: Extension to 802.11 provides up to 54 Mbps in the 5 GHz band (OFDM) 802.11b (Wi-Fi): extension of 802.11 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 20-54 Mbps over relatively short distances in the 2.4 GHz.(OFDM) 802.11n: build on MIMO offers high throughput of 100-200 Mbps 9/20/2018 Dissertation Proposal

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

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

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

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

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

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

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

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

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

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

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 3491-3495, September 2004 S. Gordon and A. Dadej. “Design of High Capacity Wireless LANs based on 802.11b Technology.” 6th International Symposium on Communications Interworking, pages 133-144, October 13-16, 2002. R. Akl and S. Park. “Optimal Access Point selection and Traffic Allocation in IEEE 802.11 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 2002. 27th Annual IEEE Conference on Local Computer Networks, pages 831-836, 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 4516-4520, 2004. 9/20/2018 Dissertation Proposal

Dissertation Proposal Questions? 9/20/2018 Dissertation Proposal