Performance Evaluation of v-eNodeB using Virtualized Radio Resource Management

With the demand upsurge for high bandwidth services, continuous increase in the number of cellular subscriptions, adoption of Internet of Things (IoT), and marked growth in Machine-to-Machine (M2M) traffic, there is great stress exerted on cellular network infrastructure. The present wireline and wireless networking technologies are rigid in nature and heavily hardware-dependent, as a result of which the process of infrastructure upgrade to keep up with future demand is cumbersome and expensive. Software-defined networks (SDN) hold the promise to decrease network rigidity by providing central control and flow abstraction, which in current network setups are hardware-based. The embrace of SDN in traditional cellular networks has led to the implementation of vital network functions in the form of software that are deployed in virtualized environments. This approach to move crucial and hardware intensive network functions to virtual environments is collectively referred to as network function virtualization (NFV). Our work evaluates the cost reduction and energy savings that can be achieved by the application of SDN and NFV technologies in cellular networks. In this thesis, we implement a virtualized eNodeB component (Radio Resource Management) to add agility to the network setup and improve performance, which we compare with a traditional resource manager. When combined with dynamic network resource allocation techniques proposed in Elastic Handoff, our hardware agnostic approach can achieve a greater reduction in capital and operational expenses through optimal use of network resources and efficient energy utilization. Advisor: Jitender S. Deogu

M2M 원격심전도를 위한 스케일러블 코딩 및 링크 적응기법

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2017. 2. 신현식.Medical telemetry is one of the most demanding applications in recent wearable computing era. Telecardiology, which uses the power of telecommunications for the remote diagnosis and treatment of heart diseases, is one of the key telemetry applications that leverages IoT-based technologies to improve patient care. Based on recent advances in wearable sensors and telecommunication technologies, this thesis proposes a universal platform for wearable daily cardiac monitoring service. First, we propose an adaptive framework for layered representation and transmission of ECG (electrocardiography) data that can accommodate a time-varying wireless channel on cellular networks. The representation, combined with the layer-based earliest deadline first (LB-EDF) scheduler, ensures that the perceptual quality of the reconstructed ECG signal does not degrade abruptly under severe channel conditions and that the available bandwidth is utilized efficiently. Simulation shows that the proposed approach significantly improves the perceptual quality of the ECG signal reconstructed at the remote monitoring station. Then we extend the proposed adaptive framework to support time-critical medical applications. In fact, the use of wireless technologies has been avoided for medical situations that demand instantaneous cardiac monitoring because of their considerable and nondeterministic end-to-end latency. This thesis introduces a universal platform for machine-to-machine (M2M) telecardiology over cellular networks, along with a novel conservative modulation and coding scheme to minimize and stabilize the delay down to 10 ms of ultra-low latency level, incurred during the process of ECG transmission over a wireless medium while maintaining the desired level of ECG pattern quality required for improving the chance of its interpretation. Machine-type communication (MTC) system is adopted for the delivery of patient ECG data to benefit from its inherent reliability, pervasiveness, security, and performance of 4G long term evolution (LTE) technologies with reduced cost and enhanced coverage. Extensive evaluations indicate that the proposed system provides a sufficient level of service for medical-grade instantaneous ECG monitoring in significantly deteriorated channel conditions.1.Introduction 1 1.1 Motivation and Objectives 1 1.2 Research Contributions 6 1.3 Orgranization of Thesis 8 2 Background and Related Works 10 2.1 ECG Generals 10 2.2 Wireless ECG 15 2.3 Wireless Medium for Telecardiology 20 2.3.1 Wireless Personal Area Networks 21 2.3.2 Wireless Local Area Networks 22 2.3.3 Cellular Networks 23 3 Scalable ECG Transmission over Cellular Networks 24 3.1 System Architecture 26 3.2 Scalable Representation of ECG Data 27 3.3 ARQ-Based Error Control Using LB-EDF 30 3.4 Performance of Wireless ECG Transmission 33 4 Conservative Modulation and Coding for Instantaneous ECG Monitoring over LTE MTC 37 4.1 Architecture of Universal M2M ECG Platform 39 4.2 Demand for Instantaneous Monitoring 43 4.3 System Requirements for Instantaneous Monitoring Services 45 4.3.1 Latency Requirements and Analysis 45 4.3.2 Presentation Requirements for Sufficient Clinical Accuracy 53 4.4 System Architecture for Instantaneous Wireless ECG Monitoring using LTE MTC 58 4.4.1 Spatio-Temporal Scalable Media Coding for ECG signal 60 4.4.2 Conservative Modulation and Coding to Provide Extra Protection for Higher Prioritized Scalable Layers 64 4.4.3 System Parameter Analysis 68 4.5 Performance Evaluation 72 4.5.1 Simulation Environment 72 4.5.2 Simulation Results 72 4.5.3 Service Level Adjustment 78 5 Conclusion 79 5.1 Summary 79 5.2 Future Research Directions 83 Bibliography 84 Abstract in Korean 103Docto

Studies on 6-sector-site deployment in downlink LTE

Mobile data traffic is expected to increase massively in the following years. Consequently, service operators are induced to increase the capacity of their networks continually to attract more subscribers and maximize their revenues. At the same time, they want to minimize operational costs and capital expenditures. Among the alternatives that aim to increase the network capacity, higher order sectorization, and in particular a six sectorized configuration, is nowadays attracting a lot of attention for LTE macro-cell deployments since a higher number of sectors per site results in improved site capacity and coverage. A six sectorized configuration is attractive for both roll-out phase and growth phase of the network. In the roll-out phase, the radio access network is planned with 6-sector sites instead of 3-sector sites with the advantage that less sites are needed for the same capacity and coverage requirements. In the growth phase, the six sectorized configuration can be used to upgrade existing 3-sector sites where the traffic grows beyond the current sites' capabilities. Therefore, no additional expensive and time consuming contracts need to be signed for the locations of the new sites, while the existing sites are used more efficiently. However, although potentially a 6-sector site can offer a double capacity than a 3-sector site, several factors prevent the capacity from growing proportionately to the number of sectors. Consequently, there is an uncertainty on whether the capacity gain is high enough to justify the extra costs of the additional equipment and, more specifically, whether the 6-sector-site deployment is more economically attractive than a 3-sector-site deployment. The aim of this report is to solve this uncertainty. First, we present the main factors that affect the capacity gain. Next, we quantify the impact of these factors on the capacity gain in downlink LTE with the use of a system level simulator. Finally, we use the results of the simulation study as inputs for an economic study to access the reasons for a possible deployment of 6-sector sites instead of 3-sector sites for LTE

China-Europe cooperation in the telecommunications: the case of China Unicom/Telefónica, 2002-2016

This research seeks to explore the driving forces behind the diverse pathways of telecommunications and, in particular, the rationale for international alliances in the context of globalisation and the extension of the value chain induced by technological change. It attempts to answer two interrelated questions: from China's side, why Telefónica and from this operator's side, why China? China was looking for a reliable technology partner for its weak market segments and a bridge to Latin America. Telefónica ambitioned to expand its mobile customer base in a country with high growth potential (NYT) while reducing through economies of scale equipment supply costs in an oligopolistic market. The research adopts a case study methodology and focuses on the service operators China Unicom and Telefónica de España in the years after the dotcom crash and before the arrival of the Covid-19 pandemic. The investigation is based on sources from the companies involved and relevant documents from specialised institutions. The study finds that the need for cooperation in the knowledge and capital-intensive services and the coincidence in strategies led to the frame of international alliances of companies

Handover management strategies in LTE-advanced heterogeneous networks.

Doctoral Degree. University of KwaZulu-Natal, Durban.Meeting the increasing demand for data due to the proliferation of high-specification mobile devices in the cellular systems has led to the improvement of the Long Term Evolution (LTE) framework to the LTE-Advanced systems. Different aspects such as Massive Multiple-Input Multiple Output (MIMO), Orthogonal Frequency Division Multiple Access (OFDMA), heterogeneous networks and Carrier Aggregation have been considered in the LTE-Advanced to improve the performance of the system. The small cells like the femtocells and the relays play a significant role in increasing the coverage and the capacity of the mobile cellular networks in LTE-Advanced (LTE-A) heterogeneous network. However, the user equipment (UE) are faced with the frequent handover problems in the heterogeneous systems than the homogeneous systems due to the users‟ mobility and densely populated cells. The objective of this research work is to analyse the handover performance in the current LTE/LTE-A network and to propose various handover management strategies to handle the frequent handover problems in the LTE-Advance heterogeneous networks. To achieve this, an event driven simulator using C# was developed based on the 3GPP LTE/LTE-A standard to evaluate the proposed strategies. To start with, admission control which is a major requirement during the handover initiation stage is discussed and this research work has therefore proposed a channel borrowing admission control scheme for the LTE-A networks. With this scheme in place, resources are better utilized and more calls are accepted than in the conventional schemes where the channel borrowing is not applied. Also proposed is an enhanced strategy for the handover management in two-tier femtocell-macrocell networks. The proposed strategy takes into consideration the speed of user and other parameters in other to effectively reduce the frequent and unnecessary handovers, and as well as the ratio of target femtocells in the system. We also consider scenarios such as the one that dominate the future networks where femtocells will be densely populated to handle very heavy traffic. To achieve this, a Call Admission Control (CAC)-based handover management strategy is proposed to manage the handover in dense femtocell-macrocell integration in the LTE-A network. The handover probability, the handover call dropping probability and the call blocking probability are reduced considerably with the proposed strategy. Finally, the handover management for the mobile relays in a moving vehicle is considered (using train as a case study). We propose a group handover strategy where the Mobile Relay Node (MRN) is integrated with a special mobile device called “mdev” to prepare the group information prior to the handover time. This is done to prepare the UE‟s group information and services for timely handover due to the speed of the train. This strategy reduces the number of handovers and the call dropping probability in the moving vehicle.Publications and conferences listed on page iv-v

Towards reliable communication in LTE-A connected heterogeneous machine to machine network

Machine to machine (M2M) communication is an emerging technology that enables heterogeneous devices to communicate with each other without human intervention and thus forming so-called Internet of Things (IoTs). Wireless cellular networks (WCNs) play a significant role in the successful deployment of M2M communication. Specially the ongoing massive deployment of long term evolution advanced (LTE-A) makes it possible to establish machine type communication (MTC) in most urban and remote areas, and by using LTE-A backhaul network, a seamless network communication is being established between MTC-devices and-applications. However, the extensive network coverage does not ensure a successful implementation of M2M communication in the LTE-A, and therefore there are still some challenges. Energy efficient reliable transmission is perhaps the most compelling demand for various M2M applications. Among the factors affecting reliability of M2M communication are the high endto-end delay and high bit error rate. The objective of the thesis is to provide reliable M2M communication in LTE-A network. In this aim, to alleviate the signalling congestion on air interface and efficient data aggregation we consider a cluster based architecture where the MTC devices are grouped into number of clusters and traffics are forwarded through some special nodes called cluster heads (CHs) to the base station (BS) using single or multi-hop transmissions. In many deployment scenarios, some machines are allowed to move and change their location in the deployment area with very low mobility. In practice, the performance of data transmission often degrades with the increase of distance between neighboring CHs. CH needs to be reselected in such cases. However, frequent re-selection of CHs results in counter effect on routing and reconfiguration of resource allocation associated with CH-dependent protocols. In addition, the link quality between a CH-CH and CH-BS are very often affected by various dynamic environmental factors such as heat and humidity, obstacles and RF interferences. Since CH aggregates the traffic from all cluster members, failure of the CH means that the full cluster will fail. Many solutions have been proposed to combat with error prone wireless channel such as automatic repeat request (ARQ) and multipath routing. Though the above mentioned techniques improve the communication reliability but intervene the communication efficiency. In the former scheme, the transmitter retransmits the whole packet even though the part of the packet has been received correctly and in the later one, the receiver may receive the same information from multiple paths; thus both techniques are bandwidth and energy inefficient. In addition, with retransmission, overall end to end delay may exceed the maximum allowable delay budget. Based on the aforementioned observations, we identify CH-to-CH channel is one of the bottlenecks to provide reliable communication in cluster based multihop M2M network and present a full solution to support fountain coded cooperative communications. Our solution covers many aspects from relay selection to cooperative formation to meet the user’s QoS requirements. In the first part of the thesis, we first design a rateless-coded-incremental-relay selection (RCIRS) algorithm based on greedy techniques to guarantee the required data rate with a minimum cost. After that, we develop fountain coded cooperative communication protocols to facilitate the data transmission between two neighbor CHs. In the second part, we propose joint network and fountain coding schemes for reliable communication. Through coupling channel coding and network coding simultaneously in the physical layer, joint network and fountain coding schemes efficiently exploit the redundancy of both codes and effectively combat the detrimental effect of fading conditions in wireless channels. In the proposed scheme, after correctly decoding the information from different sources, a relay node applies network and fountain coding on the received signals and then transmits to the destination in a single transmission. Therefore, the proposed schemes exploit the diversity and coding gain to improve the system performance. In the third part, we focus on the reliable uplink transmission between CHs and BS where CHs transmit to BS directly or with the help of the LTE-A relay nodes (RN). We investigate both type-I and type-II enhanced LTE-A networks and propose a set of joint network and fountain coding schemes to enhance the link robustness. Finally, the proposed solutions are evaluated through extensive numerical simulations and the numerical results are presented to provide a comparison with the related works found in the literature

Evaluation of Alternative Telecommunication Technologies for the Karoo Central Astronomy Advantage Area

Cite: Academy of Science of South Africa (ASSAf), (2021). Evaluation of Alternative Telecommunication Technologies for the Karoo Central Astronomy Advantage Area. [Online] Available at: DOI http://dx.doi.org/10.17159/assaf.2021/0073The National Research Foundation (NRF) requested the Academy of Science of South Africa (ASSAf), on behalf of South African Radio Astronomy Observatory (SARAO) and the Square Kilometre Array (SKA), to undertake an independent and objective evaluation of potential alternative telecommunication technologies for the areas of the Karoo Central Astronomy Advantage Areas (KCAAA). The study encompasses regulatory, public sphere, and technical dimensions to explore options for maintaining the functionality of the telescope while, at the same time, delivering appropriate connectivity solutions for local communities.The objectives of this study are as follows:1) Assess the technologies currently being, or planning to be, deployed through existing alternative communications programs managed by SARAO, including whether these technologies are comparable with market available technologies that could feasibly be deployed in the KCAAA; and2) Assessment of current and future telecommunication technologies that may act as suitable replacement and/or improvement (functional and feasible) for existing detrimental technologies, utilised in the KCAAA.This report provides a critical background into the relationship between the SKA and local communities as it relates to ICTs in the area. Based on this understanding, potential technology solutions are proposed to ensure residents of the KCAAA are still afforded valuable access to information and communication technologies (ICTs) within the parameters of affordability, desirability and feasibility.National Research Foundation (NRF