Implementation and Evaluation of timeliness in Wireless Networks: to be or not to be - on time
13 May 2019
Stadscampus, Promotiezaal van de Grauwzusters - Lange Sint-Annastraat 7 - 2000 Antwerpen (route: UAntwerpen, Stadscampus
Organization / co-organization:
Department of Mathematics & Computer Science
PhD defence Wim Torfs - Faculty of Science - Department of Mathematics & Computer Science
Timeliness and more specifically low latency and time efficient operation of networks becomes more and more important in state of the art of wireless communications. This work considers the efficiency and latency of three different networks: Wireless Sensor Network, Wireless Local Area Network and Cognitive Radio Network.
In WSNs, the timeliness presents a challenge in amongst others synchronization protocols. This work studies the hardware parts that provide an influence on the clock stability of two different platforms, and evaluates the related work by mapping it to the hardware model of both platforms. As a result of these findings, a novel synchronization protocol is proposed, which provides an abstraction of the concept timestamp.
One of the challenges in TDMA protocols is the heterogeneous character of the network, where nodes might have a different bandwidth requirement. This work discusses a novel TDMA protocol that ensures a reliable operation in such a network, while making sure that nodes with small bandwidth requirements still get regularly access to the medium. Moreover, thanks to the allocation scheme of the protocol, nodes can join or leave the network, without causing any disruption of the network operation due to schedule updates. The protocol results in a deterministic behavior in terms of buffer size and latency.
COTS hardware based on the IEEE Std 802.11n standard provides usually only support for CSMA type of medium access. However, in certain use cases, a more deterministic access to the wireless medium is required. This work elaborates on a method to modify the Linux kernel drivers in order to deliver packets according to a precise timing interval.
The final contribution of this work can be found in the area of Cognitive Radio Networks and Neighborhood Discovery protocols, where it was found that making an attempt to a Rendezvous asynchronously offers a higher performance than otherwise. By proposing an extension that induces this asynchronism, every protocol can benefit from this.