Path planning for an autonomous vehicle in a dynamic environment is a challenging problem particularly if the vehicle has to utilize its complete maneuvering abilities, perceive its environment with a high degree of accuracy and react to unsafe conditions. Trajectory planning in an environment with stationary and moving obstacles has been the topic of considerable interest in robotics communities and much of the work focuses on holonomic and non-holonomic kinematics. Optimal path planning has been approached using numerical optimization techniques planning the navigation of ground and aerial navigation producing realistic results in spite of computational complexity. Most of the previous work discussed uses static obstacles and autonomous vehicles moving in closed indoor environments involving prior knowledge of its environment using map based localization and navigation. The work that has focused on dynamic environments with moving obstacles having assumptions of completely known velocities dont account for uncertainty during obstacle motion prediction. Estimation based approaches use grid-based environment representation of the state space, discretized velocities and linear motion models. This simulation aims at finding an optimal trajectory by obtaining the optimal longitudinal and lateral maneuvers using the vehicles sensing and predictive capabilities for path planning in continuous 2-D space. The focus is on specific scenarios using spatial and temporal constraints while navigating and it involves timed maneuvering in between periods of straight line motion as for a typical unmanned ground vehicle. It also combines tracking obstacles independently and relative localization with targets to achieve its objective. The parametric space of longitudinal and lateral velocities is generated for the host vehicle aiming to reach a goal state configuration within a pre-specified time threshold. This considers independently the cases for completely known trajectories of obstacles and motion under uncertainty. The results of constrained non-linear optimization allow the vehicle to trace its trajectory given its known initial and destination configuration along with known velocity profiles, noise models and range-bearing measurements to the targets in its vicinity. Simulation results show that the proposed scenario-specific approaches produce reasonable maneuvers within the admissible velocity ranges.

The highest NIC bonding performance is achieved by the round-robin scheduling mode. However, we found that the performance was much lower than the theoretical limit due to out-of-order TCP packet delivery. So our work proposes a load-balanced NIC bonding scheduling approach as a significant improvement over the current state-of-the-art. We pro- pose that the outgoing packets should be queued on interfaces with the least amount of packets waiting to be sent. This allows the load to be well balanced over all interfaces thereby reducing the probability of packets arriving out-of-order at their destination. This work presents an analysis of all currently available NIC bonding modes in terms of perfor- mance. A new bonding simulation framework was developed to facilitate the development of alternate scheduling algorithms and compare their performance. This helped us analyze and propose load-based scheduling as a better alternative to the most popularly used round-robin scheduling mode.

The number of devices on the Internet is always increasing and there is need for reliable IP addressing. 5G network will be built on two main technologies; SDN and NFV which will make it elastic and agile compared to its predecessors. Elasticity will ensure that additional devices can always be added to the network. IPv4 addresses are already depleted and cannot support the expansion of the Internet to ensure the realization of future networks. IPv6 addressing has been proposed to support 5G networking because of the sufficient number of addresses that the protocol provides. However, IPv4 addressing will still be used concurrently with IPv6 addressing in networks until they become fully IPv6 based. The structure of IPv4 header is different from IPv6 header hence the two protocols are incompatible. There is need for seamless intercommunication between devices running IPv4 and IPv6 in future networks. Three technologies namely; Dual Stack, Tunneling and Translation have been proposed to ensure that there is smooth transition from IPv4 to IPv6 protocol. This dissertation demonstrates Tunneling of IPv6 over IPv4. Also, this research work reviews network security threats of past networks that are likely to be experienced in 5G networks. To counter them, reliable IP security strategies used in current networks are proposed for use in next generation networks. This dissertation evaluates and analyzes IPv4, IPv6 network and Tunneling models in an SDN network environment. The performance of an IPv4 only network is compared to the IPv6 only network. Also, devices addressed with both protocols are connected. The results obtained illustrate that IPv4 and IPv6 devices can effectively communicate in a 5G network environment. In addition, a tunnel is used to run IPv6 protocol over an IPv4 network. The devices on both ends of the tunnel could communicate with each other effectively.

The Internet continues to expand drastically as a result of explosion of mobile devices, content, server virtualization, and advancement of cloud services. This increase has significantly changed traffic patterns within the enterprise data centres. Therefore, advanced technologies are needed to improve traditional network deployments to enable them to handle the changing network patterns. Software defined networks (SDN) and network function virtualisation (NFV) are innovative technologies that enable network flexibility, increase network and service agility, and support service-driven virtual networks using concepts of virtualisation and softwarisation. Collaboration of these two concepts enable cloud operator to offer network-as-a-service (NaaS) to multiple tenants in a data-centre deployment. Despite the benefits brought by these technologies, they also bring along security challenges that need to be addressed and managed to ensure successful deployment and encourage faster adoption in industry. This dissertation proposes security solution based on tenant isolation, network access control (NAC) and network reconfiguration that can be implemented in NFV multi-tenant deployment to guarantee privacy and security of tenant functions. The evaluation of the proof-of-concept framework proves that SDN based tenant isolation solution provides a high level of isolation in a multi-tenant NFV cloud. It also shows that the proposed network reconfiguration greatly reduces chances of an attacker correctly identifying location and IP addresses of tenant functions within the cloud environment. Because of resource limitation, the proposed NAC solution was not evaluated. The efficiency of this solution for multitenancy NFV has been added as part of future work.

This work is motivated by the need to understand the performance of Orthogonal Frequency Division Multiplexing (OFDM) and Filterbank Multicarrier (FBMC). Multicarrier techniques are widely being considered for the development of the telecommunication systems such as the Long Term Evolution (LTE) networks, 5th Generation (5G) and beyond. One of the modulation strategies for upcoming 5G mobile communication technologies is FBMC. When compared to OFDM, which is utilised in Fourth Generation (4G) mobile communications technology, it employs multicarrier techniques that are immune to fading produced by transmission of more than one route at a time and also resistant to intersymbol interference. OFDM is one of the popular and highly recommended modulation schemes for LTE applications. OFDM is used for communications and is found in modern digital communication systems (e.g. WiFi, 4G, etc.). OFDM transmits streams of data in many orthogonal sub-carrier frequencies at varying data rates. These carriers do not interfere with each other and thus mitigate inter-symbol interference (ISI) and inter-carrier-interference (ICI). The simulation of an OFDM modulation technique, as well as the performance of OFDM in contrast to an FBMC modulation scheme in terms of delivering the same quantities of data, will be investigated using an ideal communication channel and replicated in a multipath fading channel. Using OFDM modulation techniques, a multipath channel was investigated for realistic simulations. In MATLAB, a picture was used as the input signal to identify the OFDM modulation method with the lowest bit error rate (BER). Quadrature amplitude modulation (QAM) was examined using 16QAM, 32QAM and 64QAM, Binary phase shift keying (BPSK), eight phase shift keying (8PSK), quadrature phase shift keying (QPSK), 16QAM, 32QAM and 64QAM OFDM modulation techniques were used. Channel noise is modelled by adding a white Gaussian noise (AWGN). The channel noise variance decreases with an increase in signal to noise ratio (SNR). 10dB SNR and 20dB SNR inputs were used in the simulations to obtain the BER of the recovered image. QPSK modulation scheme in a multipath fading system produced bit error rates which are higher than BER produced in BPSK modulation scheme. 8PSK modulation scheme produced a higher BER compared to BER of BPSK modulation scheme at the same input SNR. As the modulation order increased the BER increased. 64QAM has the highest BER. Frequency and Phase offsets resulted in symbol error rates increasing as the channel impairments increased in FBMC. The spectral efficiency of OFDM is higher than FBMC spectral efficiency at low burst durations. High burst duration results in FBMC spectral efficiency getting higher than OFDM spectral efficiency. Mild impairments rarely caused symbol recovery errors, but the harsh impairments caused multiple symbol errors. To reduce and eliminate the effects of multipath fading, the least squares channel estimation method is used.

Thesis (MComm. ICT)--University of the Western Cape, 2006. / Includes bibliographical references (leaves 56-63).

<p>The research focuses on the acceptance of new technologies within the telecommunications industry. The study examines three models namely Innovation theory, Theory of Reason Action (TRA), and Technology Acceptance Model (TAM). This study explores the technology acceptance models in order to explain why certain monitoring officers at ICASA would prefer specific technologies over others. Models of interest could be the innovation theory, TRA and TAM. After reviewing both models, the author will examine the TAM in detail as a model of interest in this study. In turn, this model is expected to assist us to understand why monitoring officer's at ICASA would prefer a particular frequency monitoring technology over the other.</p>

<p>The research focuses on the acceptance of new technologies within the telecommunications industry. The study examines three models namely Innovation theory, Theory of Reason Action (TRA), and Technology Acceptance Model (TAM). This study explores the technology acceptance models in order to explain why certain monitoring officers at ICASA would prefer specific technologies over others. Models of interest could be the innovation theory, TRA and TAM. After reviewing both models, the author will examine the TAM in detail as a model of interest in this study. In turn, this model is expected to assist us to understand why monitoring officer's at ICASA would prefer a particular frequency monitoring technology over the other.</p>

The study exammes the relationship between corporate and public telecommunication networks, and the role of interconnection. The telecommunication development in East Germany in the post-unification period is presented as a critical case study to examine the impact of restricted interconnection and monopolistic network supply on corporate network growth. A survey questionnaire in conjunction with in-depth interviews with large corporate users is applied to evaluate their propensity to establish private networks in East Germany. In order to generalise the results, statistical methods (logit and probit models) have been applied to several empirical data sets. The empirical findings of the analysis are compared with assumptions that have guided public policy in Germany between 1990 and 1994. The study demonstrates that interconnection accelerates network tipping, i.e., the adoption of private networks by a majority of large corporate users in conjunction with their exit from the public network. It evaluates different technical solutions to unbundle activities in digital nehvorks that enable an interconnection of corporate and public telecommunication networks In distinguishing between closed and open network access, interconnection is related to the concept of 'appropriability'. Open network access facilitates competitive network supply and undermines the traditional monopolies of the Post, Telegraph and Telephone Administrations (PTTs). Closed network access restricts competitive network supply and is a characteristic of a network design controlled by a dominant PTT. The study argues that closed network access can lead to a 'lock-in' configuration, i.e, an inefficient adoption of network technologies It postulates that the 'lock-in' situation in the East German telecommunication sector in the 19905 is due to the instantaneous application of the West German regulatory framework and monopolistic inefficiencies of German Telekom. The main conclusion is that there is a need to reconsider the traditional 'natural' monopoly as the most appropriate industrial structure to accelerate infrastructure development in countries with poorly developed telecommunication networks especially in East and Central East Europe. Moreover, it is argued that the expansion of corporate networks can contribute to the modernisation of telecommunication infrastructure when open network access is permitted. However, the specific circumstances in which open interconnection policies can facilitate the modernisation of the public network depend on a large number of country specific features. These are examined in detail for the case of the former East Germany.

The future mobile communication networks are expected to cope with growing local usage patterns especially in dense urban areas at more affordable deployment and operation expenses. Beyond leveraging small cell architectures and advanced radio access technologies; more radio spectrum are expected to be required to achieve the desired techno-economic targets. However, securing efficient radio spectrum resources remain a challenging task especially in the bands with favored propagation characteristics. Therefore, the research activity has been directed towards discussing the benefits and needs for more flexible and local spectrum authorization schemes. This thesis work is meant to be a contribution to this ongoing discussion from a techno-economic perspective  that aim to investigate three main questions: (i) how can the need for and benefit of local spectrum authorization schemes be valued from the perspective of established mobile network operators, and (ii) Will the shift towards more flexible and local spectrum authorization schemes impact the existing mobile service ecosystem and in what manner. In chapter three, the role and value of the different local spectrum authorization schemes in shaping an economic viable provision strategy for the targeted local mobile services in future dense urban areas are investigated. For this purpose, the opportunity cost approach is used to evaluate the elasticity of substitution between the spectrum resources and network infrastructure. The main results in chapter three indicate the economic incentives to deploy more small cells based on local spectrum authorization schemes are subject to the additional deployment and operation costs that can be avoided if a macro-cell layer is deployed instead. However, the backhaul links costs and additional radio equipment cost for aggregating spectrum resources in different bands at the small cell level will have high impact on the anticipated  engineering value. Nonetheless; in dense and very dense deployment scenarios of small cells, where the density of radio sites is equal or larger than the active mobile subscribers' density, access more spectrum resources based on local authorization schemes will have a key role in providing the targeted high mean instantaneous data rate per active end-subscriber. Moreover, established actors (e.g. incumbent MNOs) experiencing shortage in their licensed spectrum resources can evaluate the spectrum value base on their ability to offer the targeted mobile services in strategic spotty local areas. While in chapter four, the possible business and cooperation models around local shared spectrum authorization from the perspectives of established mobile network operators (MNOs) and emerging local network operators (LNOs) are identified. From the perspective of an established MNO, the strategic value of the flexible spectrum authorization option could be very high in certain local environments with potential high return on investment (ROI). On the other hand, emerging actors can benefit from the flexible spectrum authorization options to focus on the niche market in certain local areas. Other viable business models for an emerging actor rest with the possibility to enter into different cooperation agreements to deploy and operate dedicated local mobile infrastructure on behalf established mobile network operators; especially in situations where the deployment of mobile networks brings extra activities and overheads to the MNOs.  Moreover, by allowing other actors, rather than the traditional mobile network operators, to access spectrum resource at a reasonable or no cost, one of the major traditional investment barriers in mobile market will be relaxed and consequently more independent business models may emerge. As an example, actors with sufficient technical expertise such as network equipment vendors may exploit local shared spectrum resources to provide tailored local mobile services and enter into different roaming agreements with established mobile network operators. / <p>QC 20170411</p>