IMPROVE CONNECTION TIME, CONGESTION CONTROL AND POWER SAVE MECHANISM OF 802.11 WIRELESS DEVICES WITH CHANGES IN MAC LAYER

Abstract

802.11 handheld devices have increasingly supported based wireless local area networks (WLAN). With the growth of Wi-Fi over time, performance and quality are facing many challenges. Wi-Fi works on the principle of the IEEE 802.11-based carrier sense multiple access collision avoidance (CSMA/CA) to transmit packets and distributed coordination function (DCF) protocol based on inter-frame spacing used to make the gap between two frames. DCF protocol functioning & its performance depends on the number of participating devices in the environment. With the increasing number of 802.11 devices, congestion increase in the environment. In the DCF manner, an 802.11 device gets limited time in the environment to finish its activity, with a rapid increase in the number of devices in the 802.11 environments. The critical operation is always connecting a Wi-Fi device with another device. Another device can be an access point or any other Wi-Fi device (ad-hoc or Wi-Fi direct mode). However, supporting WLAN functionality is hugely energy-consuming since the connectivity must be maintained even when the device is idle. The power management defined in the 802.11 standards does not identify detailed techniques to handle the problem caused by power consumption-affecting factors (PCAFs) since most of these factors have not been specified in the standards. The Wi-Fi experience of users is influenced by various quality metrics, including throughput, latency, connection, the probability of successfully connecting to Wi-Fi access points, the time taken to set up a Wi-Fi connection, security, power consumption by battery-operated devices, and collision/congestion control. Among these metrics, the probability of successfully connecting to Wi-Fi access points, the time taken to set up a Wi-Fi connection, power consumption, and collision/congestion control is considered the most essential. This thesis aims to investigate how different factors affect the above discussed metrics in 802.11 WLANs. To simplify the problem, only infrastructure mode is taken into account. A couple of sub-problems are derived from the main problem. The protocol-related practical solution proposed for all the identified sub- problems. The simulators and real hardware have validated the accuracy of the obtainedsolutions according to availability. This research successfully provides a more reliable, effective, optimal, easy to implement/deploy and practical solution for Wi-Fi device problems. vi The three main areas of focus are: Improved connection time: The proposed changes to the MAC layer could potentially improve the connection time of 802.11 wireless devices. This is because the changes could reduce the number of handshakes and other overhead that is required to establish and maintain a connection. Improved congestion control: The proposed changes to the MAC layer could also potentially improve the congestion control of 802.11 wireless networks. This is because the changes could allow for more efficient use of the environment, which could help to prevent congestion and packet loss. Improved power save mechanism: The proposed changes to the MAC layer could also potentially improve the power save mechanism of 802.11 wireless devices. This is because the changes could allow devices to sleep for longer periods of time without losing connectivity, which could help to extend the battery life of devices. In addition to these specific contribution points, the thesis could also make a number of general contributions to the field of wireless networking. For example, the thesis could provide new insights into the design of MAC layers for wireless networks, and it could also help to identify new opportunities for improving the performance of 802.11 wireless networks.