Towards QoS-Aware Load Balancing for High Density Software Defined Wi-Fi Networks

Sohaib Manzoor,Wenqing Cheng,Yayu Gao,Xiaojun Hei,Ze Chen

doi:10.1109/access.2020.3004772

Sohaib Manzoor, Wenqing Cheng + Show 3 more

Open Access

https://doi.org/10.1109/access.2020.3004772

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Abstract

High density Wi-Fi networks require load balancing in order to ensure quality of service (QoS). In the traditional Wi-Fi networks, the wireless stations learn the access points (APs) load and make the association decisions themselves leading to uneven load distribution among the APs. The new paradigm, software defined networking (SDN), has a centralized architecture, which allows to manage, measure and control high density Wi-Fi networks easily. In this paper we propose a QoS-aware load balancing strategy (QALB) for software defined Wi-Fi networks (SD-Wi-Fi), as a solution to address the problem of Wi-Fi congestion among the OpenFlow enabled APs (OAPs). The SDN controller selects a load level up to which the association decisions are made by the OAPs without consulting the controller. The wireless stations from an overloaded OAP are handed to an underloaded OAP by considering multi-metrics such as the packet loss rate, received signal strength indicator (RSSI) and throughput. An emulation platform and a large-scale-low-cost testbed with the same settings are constructed to evaluate the performance of our load balancing strategy. The results show that in comparison to four non-static schemes such as, channel measurement based access selection scheme (CMAS), (DL-SINR) downlink-signal to interference plus noise ratio AP selection scheme (DASA), mean probe delay scheme (MPD) and RSSI scheme, the proposed QALB, optimizes the throughput up to 16%, reduces the average frame delay up to 19%, minimizes the number of re-transmissions by 49%, reduces the number of handoffs by 15%, improves the degree of load balancing by 22% and minimizes the re-association times by 38%, in high density SD-Wi-Fi.

Highlights

The popularity of the Wi-Fi networks has increased rapidly in the past decade due to their facile connectivity anywhere and anytime
The destination OpenFlow enabled APs (OAPs) is chosen based on multi-metrics such as packet loss rate, received signal strength indicator (RSSI), and throughput
The network management is accomplished as the software defined networking (SDN)-based centralized control divides the OAPs into the overloaded and underloaded classes, manage the load level to balance the load among all the OAPs and choose the best underloaded destination OAP for the wireless stations to re-associate

Summary

Introduction

The popularity of the Wi-Fi networks has increased rapidly in the past decade due to their facile connectivity anywhere and anytime. Wi-Fi networks are commonly found in smart learning, smart health care, smart homes and shopping malls. The APs that provide access to the network are deployed in a spontaneous manner resulting in high variable AP densities and uneven load distribution among the APs [1], [2]. The smallest block in the Wi-Fi network is the basic service set (BSS), in which an AP acts as a bridge for wireless stations to provide access to the network. The wireless stations roam between one BSS to another sending re-association request to new APs in the vicinity. IEEE 802.11 standard supports the seamless roaming among the interconnected BSSs. The BSSs

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