This thesis addresses the problem of protocol verification. We first present a brief review of the existing specification methods for communication protocols, with emphasis on the hybrid techniques. The alternating bit protocol is specified in ISO/FDT, BBN/FST and UNISPEX to provide a comparison between three interesting hybrid models of protocol specification. A method for applying the unbounded state Temporal Logic to verify a protocol specified in a hybrid technique (in particular FDT) is outlined. Finally, a new specification and verification method called SETL is proposed, which is based on event sequences and temporal logic. To illustrate the method two data transfer protocols namely, the stop-wait and alternating bit protocols are specified in SETL and verified. We demonstrate that SETL is a generalization of the hybrid techniques, it is sound and that it can be semi-automated. / Science, Faculty of / Computer Science, Department of / Graduate

VALISYN, an automated system for the validation and synthesis of error-free protocols has been implemented in C language. It assists designers in the detection and prevention of various kinds of potential design errors, such as state deadlocks, non-executable interactions, unspecified receptions and state ambiguities. The technique employed is a stepwise application of a set of production rules which guarantee complete reception capability. These rules are implemented in a tracking algorithm, which prevents the formation of non-executable interactions and unspecified receptions, and which monitors the existence of state deadlocks and state ambiguities. The implementation of VALISYN is discussed and a number of protocol validation and synthesis examples are presented to illustrate its use and features. / Science, Faculty of / Computer Science, Department of / Graduate

Thesis (MSc.) -- University of Limpopo, 2017 / The notion of ubiquitous computing, Internet of things (IoT), big data, cloud computing and other emerging technologies has brougt forward the innovative paradigms and incredible developments in wireless communication technologies. The Wireless Mesh Networks (WMNs) technology has recently emerged as the promising high speed wireless technology to provide the last mile broadband Internet access and deliver flexible and integrated wireless communication solutions. The WMNs has the potential to enable people living in rural, peri-urban areas and small businesses to interconnect their networks and share the affordable Internet connectivity. The recent multimedia applications developed, such as voice over Internet protocol (VoIP), online gaming, cloud storage, instant messaging applications, and video sharing applications require high speed communication media and networks. These applications have witnessed enormous growth in the recent decade and continue to enhance communication amongst the users. Hence, the WMNs must have adequate capacity to support high bandwidth and real-time and multimedia applications. While the wireless communications networks are dependent on the radio frequency (RF) spectrum, the traditional wireless technologies utilise the RF spectrum bands inefficiently, resulting in sporadic and underutilisation of the RF spectrum. This inefficient usage of RF spectrum calls for novel techniques to leverage the available RF spectrum amongst different players in the wireless communication arena. There have been developments on integration of the WMNs with cognitive ratios to allow unlicensed users of RF spectrum to operate in the licensed portions of spectrum bands. This integration will provide the required bandwidth to support the required high speed broadband communication infrastructure. In this dissertation, we focus our research on the routing layer in a multi-hop wireless network environment. We addressed the routing challenges in both the WMNs and the cognitive radio based wireless mesh networks (CR-WMNs). The primary focus was to identify the routing protocols most suitable for the dynamic WMN environment. Once identified, the routing protocol was then ported to the CR-WMN environment to evaluate its performance given all the dynamics of cognitive radio environment. vi We further proposed the routing protocol called the extended weighted cumulative expected transmission time (xWCETT) routing protocol for the CR-WMNs. The design of our proposed xWCETT routing protocol is based on the multi-radio multi-channel architecture as it gives the base framework matching the cognitive radio environment. The xWCETT integrates features from the Ad-hoc On-demand Distance Vector (AODV) routing protocol and the weighted cumulative expected transmission time (WCETT) routing metric. The xWCETT was implemented using the Cognitive Radio Cognitive Network (CRCN) patch ported in network simulator (NS2) to incorporate the shared and dynamic spectrum access features. We compared the performance of our proposed xWCETT routing protocol with the AODV, dynamic source routing (DSR), the optimised link source routing (OLSR), Destination Sequences Distance Vector (DSDV), and the CRCN-WCETT routing protocols. The extensive simulation and numerical results show that the proposed xWCETT protocol obtained on average, around 10% better performance results in the CR-WNNs as compared to its routing counterparts. The comparative analysis and evaluation was performed in terms of the average end-to-end latency, throughput, jitter, packet delivery ratio, as well as the normalised routing load. The performance results obtained indicates that the proposed xWCETT routing protocol is a promising routing solution for dynamic CR-WMNs environment. / National Research Foundation (NRF)

No description available.

The all-over trend for an universal access and ubiquitous access to the Internet is driving a revolution in our societies. In order to support this era of nomadic applications, new flexible network architectures have emerged. They are referred to as “wireless ad-hoc networks.” Since human-operated devices will more likely be used indoor, it leads to many issues related to the strength of the fading in this environment. Recently, it has been suggested that a possible interaction might exist between various parameters of the ad-hoc networks and, more precisely, between the propagation model and the routing protocol. To address this question, we present in this dissertation a cross-layer perspective of the analysis of these indoor ad-hoc networks. Our reasoning is made of four stages. First, the cross-layer interactions are analyzed by the means of multivariate statistical techniques. Since a cross-layering between the physical layer and the routing protocol has been proven to be significant, we further investigate the possible development a physical layer-constrained routing algorithm. Second, fundamental equations governing the wireless telecommunications systems are developed in order to provide insightful informations on how a reliable routing strategy should be implemented in a strongly-faded environment. After that, and in order to allow a better spatial reuse, the routing protocol we propose is further enhanced by the adjonction of a power control algorithm. This last feature is extensively analyzed and a closed-form expression of the link probability of outage in presence of non-homogeneous transmission powers is given. Numerous simulations corroborate the applicability and the performance of the derived protocol. Also, we evaluate the gain, in terms of radio channel ressources, that has been achieved by the means of the power control algorithm. Third, an architecture for the interconnection with a cellular network is investigated. A closed-form expression of the relaying stability of a node is given. This equation expresses the minimal requirement that a relaying node from the ad-hoc network must fullfil in order to bridge properly the connections to the base-station. Finally, a real-life implementation is provided as a validation of the applicability of this novel ad-hoc routing protocol. It is concluded that, both from the performance and the spatial re-use point-of-views, it can be taken advantage from the cross-layering between the physical and the routing layers to positively enhance the networking architectures deployed in an indoor environment.

No description available.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Dec. 5, 2007). PDF text: xvi, 142 p. : ill. ; 5 Mb. UMI publication number: AAT 3273188. Includes bibliographical references. Also available in microfilm and microfiche formats.

The goal of this thesis is to provide an adaptable protocol stack architecture for data fusion applications. Towards the goal, this thesis presents the design of SensorStack, that addresses three key issues. First, towards network-level adaptability, how to dynamically adapt the placement of a fusion application task graph on the network? We have designed a distributed role assignment algorithm and implemented in the context of DFuse, a framework for distributed data fusion. Second, towards node-level adaptability, how to facilitate cross-layering on a node to foster agile adaptation of a node's behavior commensurate with the network-level changes? SensorStack provides information exchange service (IES) as a framework for cross-module information exchange. Finally, towards tying the network and node level adaptability together, control data published in IES needs to be shared across the network. SensorStack uses a probabilistic broadcast based dissemination service (IDS) for control data. We implement SensorStack in TinyOS and Linux to validate the SensorStack design, and use simulation experiments to investigate its network performance. Experiments demonstrate the utility of adaptability in SensorStack to increase application longevity.

Source: Masters Abstracts International, Volume: 46-05, page: 2660. Adviser: Arch I. Carson. Includes bibliographical references.

Thesis--Auburn University, 2007. / Abstract. Includes bibliographic references (p.44-46).