Infrastructure power saving and quality-of-service provisioning framework for wireless LAN mesh networks

Internet access using IEEE 802.11 wireless local area networks has become very common. In home and office networks where voice, video and audio will be delivered, quality of service (QoS) support is essential so that customers can be offered video on demand, audio on demand, voice over IP and high-speed Internet access. In addition to the proliferation of WLAN hotspots, WLAN mesh networks are now being used as a cost-effective means for coverage extension and backhaul relaying between IEEE 802.11 access points (APs).;In this thesis, we propose and investigate a comprehensive framework for a power saving QoS-enabled access point (PSQAP), intended for use in solar and low power IEEE 802.11 infrastructure applications. An energy-efficient media access control protocol is proposed using the contention-based channel access mode for IEEE 802.11. When real-time flows are present, a PSQAP schedules its awakening/sleeping pattern in a manner that satisfies the delay and packet loss requirements for the admitted real-time flows. A dynamic connection-admission control algorithm is proposed for efficient management of wireless resources. We show that both background traffic and the synchronization of stations' transmissions due to AP's alternating between awake and sleep states can cause excess queuing and packet collision rate. These effects result in an increase in packet delay and power consumption at the mobile stations in contention-based channel access mode. We propose and investigate several scheduling methods for mitigating these effects. It is also shown that voice over IP over WLAN (VoWLAN) suffers a low capacity problem and high handset/AP power consumption. A novel adaptive voice packetization scheme is proposed which improves VoIP capacity and reduces power consumption. The work in this thesis is characterized by analytical models and evaluated through extensive network simulations to study and analyze the key performance aspects of the proposed framework and the associated protocols.;In conventional IEEE 802.11, APs are always continuously powered using fixed wired connections. In future WLAN mesh networks however, wired power connections may not always be readily available, especially in Wi-Fi hotzone installations which cover expansive outdoor areas. In such cases, fixed power connections can often be replaced by a battery operated or solar powered design. For this reason, power saving on the AP is highly desirable for this type of application. Unfortunately, this is not possible since the existing IEEE 802.11 standard requires that APs remain active at all times.