Quality of Service (QoS) provisioning in multihop ad hoc networks

A multihop wireless ad hoc network consists of a number of nodes that form a dynamic topology with ad hoc wireless links among neighboring nodes. These nodes are typically limited in resources such as bandwidth, computation power, memory, and battery. Quality of Service (QoS) is usually defined as a set of service requirements that need to be met by the network while transporting a packet stream from source to destination. With the increasing needs of QoS provisioning for evolving applications such as realtime audio/video, it is desirable to support these services in ad hoc networking environments. This dissertation investigates QoS provisioning techniques for this type of networks.; QoS aware routing is an important building block for QoS support. This dissertation first proposes a Positional Attributes based Nexthop Determination Algorithm (PANDA) for flooding based route discovery in wireless ad hoc networks. PANDA has very versatile capabilities and can be used to achieve a variety of routing goals such as shortest hop routing, power conservation routing, and load balancing routing.; Mobility models have great impact on the performance of ad hoc routing protocols. This dissertation proposes a Location Aided Knowledge Extraction Routing (LAKER) protocol based on the "Restricted Random Waypoint" mobility model. Complementary to PANDA's efforts in search for better end-to-end routes, the design of LAKER is aimed to reduce flooding overhead by taking advantage of topological characteristics (for example, distribution of population density) of non-uniform net work environments. LAKER learns from past actions to guide future routing process, and as such can narrow the search space and reduce routing overhead. LAKER can also smartly overcome the problem of "void" areas in ad hoc networks.; Due to very limited battery resource, energy consumption is tightly integrated with QoS provisioning abilities of the wireless nodes. This dissertation investigates the severe problem of uneven energy consumption rates in wireless sensor networks that have a many-to-one communication model. We develop the "energy hole" model to analyze this problem, and point out the factors that have great impact on energy consumption rates. Based on our model, we study the effectiveness of several approaches towards mitigating the "energy hole" problem, and the simulation results verify our analysis.; In multihop networking environments, QoS provisioning needs to satisfy end-to-end requirements. The dissertation proposes an Adaptive Per Hop Differentiation (APHD) scheme towards achieving end-to-end QoS support in multihop wireless net works. APHD scheme incorporates IEEE 802.11e EDCA technique into multihop environments, and it can provide excellent end-to-end delay assurance while achieving much higher network utilization, compared to a pure EDCA scheme.