User-oriented mobility management in cellular wireless networks

2020 Spring.Includes bibliographical references.Mobility Management (MM) in wireless mobile networks is a vital process to keep an individual User Equipment (UE) connected while moving within the network coverage area—this is required to keep the network informed about the UE's mobility (i.e., location changes). The network must identify the exact serving cell of a specific UE for the purpose of data-packet delivery. The two MM procedures that are necessary to localize a specific UE and deliver data packets to that UE are known as Tracking Area Update (TAU) and Paging, which are burdensome not only to the network resources but also UE's battery—the UE and network always initiate the TAU and Paging, respectively. These two procedures are used in current Long Term Evolution (LTE) and its next generation (5G) networks despite the drawback that it consumes bandwidth and energy. Because of potentially very high-volume traffic and increasing density of high-mobility UEs, the TAU/Paging procedure incurs significant costs in terms of the signaling overhead and the power consumption in the battery-limited UE. This problem will become even worse in 5G, which is expected to accommodate exceptional services, such as supporting mission-critical systems (close-to-zero latency) and extending battery lifetime (10 times longer). This dissertation examines and discusses a variety of solution schemes for both the TAU and Paging, emphasizing a new key design to accommodate 5G use cases. However, ongoing efforts are still developing new schemes to provide seamless connections to the ever-increasing density of high-mobility UEs. In this context and toward achieving 5G use cases, we propose a novel solution to solve the MM issues, named gNB-based UE Mobility Tracking (gNB-based UeMT). This solution has four features aligned with achieving 5G goals. First, the mobile UE will no longer trigger the TAU to report their location changes, giving much more power savings with no signaling overhead. Instead, second, the network elements, gNBs, take over the responsibility of Tracking and Locating these UE, giving always-known UE locations. Third, our Paging procedure is markedly improved over the conventional one, providing very fast UE reachability with no Paging messages being sent simultaneously. Fourth, our solution guarantees lightweight signaling overhead with very low Paging delay; our simulation studies show that it achieves about 92% reduction in the corresponding signaling overhead. To realize these four features, this solution adds no implementation complexity. Instead, it exploits the already existing LTE/5G communication protocols, functions, and measurement reports. Our gNB-based UeMT solution by design has the potential to deal with mission-critical applications. In this context, we introduce a new approach for mission-critical and public-safety communications. Our approach aims at emergency situations (e.g., natural disasters) in which the mobile wireless network becomes dysfunctional, partially or completely. Specifically, this approach is intended to provide swift network recovery for Search-and-Rescue Operations (SAROs) to search for survivors after large-scale disasters, which we call UE-based SAROs. These SAROs are based on the fact that increasingly almost everyone carries wireless mobile devices (UEs), which serve as human-based wireless sensors on the ground. Our UE-based SAROs are aimed at accounting for limited UE battery power while providing critical information to first responders, as follows: 1) generate immediate crisis maps for the disaster-impacted areas, 2) provide vital information about where the majority of survivors are clustered/crowded, and 3) prioritize the impacted areas to identify regions that urgently need communication coverage. UE-based SAROs offer first responders a vital tool to prioritize and manage SAROs efficiently and effectively in a timely manner

Paging and Location Management in IEEE 802.16j Multihop Relay Network

IEEE 802.16j is an emerging wireless broadband networking standard that integrates infrastructure base stations with multihop relay technology. Based on the idle mode operation in IEEE 802.16j, we propose a novel location management and paging scheme. It integrates the paging area-based and the timer-based location update mechanism. In paging area-based scheme, an idle mode mobile station updates when it moves to a new paging area. In timer-based scheme, an idle mode MS updates when the location update timer expires. In this work, we formulate the mathematical model to evaluate the performance of the proposed paging scheme. A new random walk mobility model that is suitable for modeling in multihop relay network is created. Optimization of location update timer is also investigated

Traffic and mobility management in large-scale networks of small cells

The growth in user demand for higher mobile data rates is driving Mobile Network Operators (MNOs) and network infrastructure vendors towards the adoption of innovative solutions in areas that span from physical layer techniques (e.g., carrier aggregation, massive MIMO, etc.) to the Radio Access Network and the Evolved Packet Core, amongst other. In terms of network capacity, out of a millionfold increase since 1957, the use of wider spectrum (25x increase), the division of spectrum into smaller resources (5x), and the introduction of advanced modulation and coding schemes (5x) have played a less significant role than the improvements in system capacity due to cell size reduction (1600x). This justifies the academic and industrial interest in short-range, low-power cellular base stations, such as small cells. The shift from traditional macrocell-based deployments towards heterogeneous cellular networks raises the need for new architectural and procedural frameworks capable of providing a seamless integration of massive deployments of small cells into the existing cellular network infrastructure. This is particularly challenging for large-scale, all-wireless networks of small cells (NoS), where connectivity amongst base stations is provided via a wireless multi-hop backhaul. Networks of small cells are a cost-effective solution for improving network coverage and capacity in high user-density scenarios, such as transportation hubs, sports venues, convention centres, dense urban areas, shopping malls, corporate premises, university campuses, theme parks, etc. This Ph.D. Thesis provides an answer to the following research question: What is the architectural and procedural framework needed to support efficient traffic and mobility management mechanisms in massive deployments of all-wireless 3GPP Long-Term Evolution networks of small cells? In order to do so, we address three key research challenges in NoS. First, we present a 3GPP network architecture capable of supporting large-scale, all-wireless NoS deployments in the Evolved Packet System. This involves delegating core network functions onto new functional entities in the network of small cells, as well as adapting Transport Network Layer functionalities to the characteristics of a NoS in order to support key cellular services. Secondly, we address the issue of local location management, i.e., determining the approximate location of a mobile terminal in the NoS upon arrival of an incoming connection from the core network. This entails the design, implementation, and evaluation of efficient paging and Tracking Area Update mechanisms that can keep track of mobile terminals in the complex scenario of an all-wireless NoS whilst mitigating the impact on signalling traffic throughout the local NoS domain and towards the core network. Finally, we deal with the issue of traffic management in large-scale networks of small cells. On the one hand, we propose new 3GPP network procedures to support direct unicast communication between LTE terminals camped on the same NoS with minimal involvement from functional entities in the Evolved Packet Core. On the other hand, we define a set of extensions to the standard 3GPP Multicast/Broadcast Multimedia Service (MBMS) in order to improve the quality of experience of multicast/broadcast traffic services in high user-density scenarios.El crecimiento de la demanda de tasas de transmisión más altas está empujando a los operadores de redes móviles y a los fabricantes de equipos de red a la adopción de soluciones innovadoras en áreas que se extienden desde técnicas avanzadas de capa física (agregación de portadoras, esquemas MIMO masivos, etc.) hasta la red de acceso radio y troncal, entre otras. Desde 1957 la capacidad de las redes celulares se ha multiplicado por un millón. La utilización de mayor espectro radioeléctrico (incremento en factor 25), la división de dicho espectro en recursos más pequeños (factor 5) y la introducción de esquemas avanzados de modulación y codificación (factor 5) han desempeñado un papel menos significativo que las mejoras en la capacidad del sistema debidas a la reducción del tamaño de las celdas (factor 1600). Este hecho justifica el interés del mundo académico y de la industria en estaciones base de corto alcance y baja potencia, conocidas comúnmente como small cells. La transición de despliegues tradicionales de redes celulares basados en macroceldas hacia redes heterogéneas pone de manifiesto la necesidad de adoptar esquemas arquitecturales y de procedimientos capaces de proporcionar una integración transparente de despliegues masivos de small cells en la actual infraestructura de red celular. Este aspecto es particularmente complejo en el caso de despliegues a gran escala de redes inalámbricas de small cells (NoS, en sus siglas en inglés), donde la conectividad entre estaciones base se proporciona a través de una conexión troncal inalámbrica multi-salto. En general, las redes de small cells son una solución eficiente para mejorar la cobertura y la capacidad de la red celular en entornos de alta densidad de usuarios, como núcleos de transporte, sedes de eventos deportivos, palacios de congresos, áreas urbanas densas, centros comerciales, edificios corporativos, campus universitarios, parques temáticos, etc. El objetivo de esta Tesis de Doctorado es proporcionar una respuesta a la siguiente pregunta de investigación: ¿Cuál es el esquema arquitectural y de procedimientos de red necesario para soportar mecanismos eficientes de gestión de tráfico y movilidad en despliegues masivos de redes inalámbricas de small cells LTE? Para responder a esta pregunta nos centramos en tres desafíos clave en NoS. En primer lugar, presentamos una arquitectura de red 3GPP capaz de soportar despliegues a gran escala de redes inalámbricas de small cells en el Evolved Packet System, esto es, el sistema global de comunicaciones celulares LTE. Esto implica delegar funciones de red troncal en nuevas entidades funcionales desplegadas en la red de small cells, así como adaptar funcionalidades de la red de transporte a las características de una NoS para soportar servicios celulares clave. En segundo lugar, nos centramos en el problema de la gestión de movilidad local, es decir, determinar la localización aproximada de un terminal móvil en la NoS a la llegada de una solicitud de conexión desde la red troncal. Esto incluye el diseño, la implementación y la evaluación de mecanismos eficientes de paging y Tracking Area Update capaces de monitorizar terminales móviles en el complejo escenario de redes de small cells inalámbricas que, a la vez, mitiguen el impacto sobre el tráfico de señalización en el dominio local de la NoS y hacia la red troncal. Finalmente, estudiamos el problema de gestión de tráfico en despliegues a gran escala de redes inalámbricas de small cells. Por un lado, proponemos nuevos procedimientos de red 3GPP para soportar comunicaciones unicast directas entre terminales LTE registrados en la misma NoS con mínima intervención por parte de entidades funcionales en la red troncal. Por otro lado, definimos un conjunto de extensiones para mejorar la calidad de la experiencia del servicio estándar 3GPP de transmisión multicast/broadcast de tráfico multimedia (MBMS, en sus siglas en inglés) en entornos de alta densidad de usuarios

Radio Spectrum and the Disruptive Clarity OF Ronald Coase.

In the Federal Communications Commission, Ronald Coase (1959) exposed deep foundations via normative argument buttressed by astute historical observation. The government controlled scarce frequencies, issuing sharply limited use rights. Spillovers were said to be otherwise endemic. Coase saw that Government limited conflicts by restricting uses; property owners perform an analogous function via the "price system." The government solution was inefficient unless the net benefits of the alternative property regime were lower. Coase augured that the price system would outperform the administrative allocation system. His spectrum auction proposal was mocked by communications policy experts, opposed by industry interests, and ridiculed by policy makers. Hence, it took until July 25, 1994 for FCC license sales to commence. Today, some 73 U.S. auctions have been held, 27,484 licenses sold, and $52.6 billion paid. The reform is a textbook example of economic policy success. We examine Coase‘s seminal 1959 paper on two levels. First, we note the importance of its analytical symmetry, comparing administrative to market mechanisms under the assumption of positive transaction costs. This fundamental insight has had enormous influence within the economics profession, yet is often lost in current analyses. This analytical insight had its beginning in his acclaimed early article on the firm (Coase 1937), and continued into his subsequent treatment of social cost (Coase 1960). Second, we investigate why spectrum policies have stopped well short of the property rights regime that Coase advocated, considering rent-seeking dynamics and the emergence of new theories challenging Coase‘s property framework. One conclusion is easily rendered: competitive bidding is now the default tool in wireless license awards. By rule of thumb, about$17 billion in U.S. welfare losses have been averted. Not bad for the first 50 years of this, or any, Article appearing in Volume II of the Journal of Law & Economics.

Increasing Spectrum for Broadband: What Are The Options?

The growth of wireless broadband is a bright spot in the U.S. economy, but a shortage of flexibly licensed spectrum rights could put a crimp on this expansion. Freeing up spectrum from other uses would allow greater expansion of wireless broadband and would bring substantial gains—likely in the hundreds of billions of dollars—for U.S. consumers, businesses, and the federal treasury. ... U.S. experience suggests that it takes at least six years, and possibly over a decade, to complete any large-scale reallocation of spectrum. Thus, for policymakers, the ?projected? need is actually here today. This paper makes three proposals to increase spectrum available for wireless broadband under a flexibly licensed, market-based regime.

Location Management Techniques in Cellular Network: a Novel Approach

Communication had become the necessity of our lives. It is no longer just a way to communicate with each other. It is now a part of our life. Most of this changes are the result of the rapid growth in mobile industry. The number of subscribers are increasing in an exponential manner. At current stage the number of mobile devices had already crossed the total human population of our planet. But this high paced increase in number of subscribers had brought in some new and challenging problems into the eld also. Particularly the problem of ccommodating this huge number of subscribers into the limited amount of spectrum, withoutcompromising the Grade of Service. In this thesis we had tried to address this issue by reducing the spectrum utilization in the location management. Location management are the set of techniques that are used by the telecom provider to determine the current location of the user (location update) and to inform the user regarding an incoming call (paging). Both of this process consumes a huge portion of the available spectrum. This thesis presents a dynamic pro le based location management technique that optimizes both these technology. When simulated using actual user data, the algorithm shows it is 3 times more ecient than the conventional paging and 2 times more ecient compared to other intelligent paging algorithms. Similarly in case of location update, the algorithm shows an improvement of 17% compared to the conventional technique. The thesis also includes a comparison between sequential paging and concurrent paging based on parameters like probability of channel being busy,average waiting time per user etc.The novelty of this work is that it uses CDR (Call Data Record) to pro le the users. And the algorithm is implemented on actual user data rather than any theoretically predicted data. The optimization is done at individual user level. So the optimization achieved through the proposed algorithm is greater compared to other algorithms. The final output shows promising result specically in terms of bandwidth conservatio

Location Management Techniques in Cellular Network: a Novel Approach

Communication had become the necessity of our lives. It is no longer just a way to communicate with each other. It is now a part of our life. Most of this changes are the result of the rapid growth in mobile industry. The number of subscribers are increasing in an exponential manner. At current stage the number of mobile devices had already crossed the total human population of our planet. But this high paced increase in number of subscribers had brought in some new and challenging problems into the eld also. Particularly the problem of ccommodating this huge number of subscribers into the limited amount of spectrum, withoutcompromising the Grade of Service. In this thesis we had tried to address this issue by reducing the spectrum utilization in the location management. Location management are the set of techniques that are used by the telecom provider to determine the current location of the user (location update) and to inform the user regarding an incoming call (paging). Both of this process consumes a huge portion of the available spectrum. This thesis presents a dynamic pro le based location management technique that optimizes both these technology. When simulated using actual user data, the algorithm shows it is 3 times more ecient than the conventional paging and 2 times more ecient compared to other intelligent paging algorithms. Similarly in case of location update, the algorithm shows an improvement of 17% compared to the conventional technique. The thesis also includes a comparison between sequential paging and concurrent paging based on parameters like probability of channel being busy,average waiting time per user etc.The novelty of this work is that it uses CDR (Call Data Record) to pro le the users. And the algorithm is implemented on actual user data rather than any theoretically predicted data. The optimization is done at individual user level. So the optimization achieved through the proposed algorithm is greater compared to other algorithms. The final output shows promising result specically in terms of bandwidth conservatio

Prioritised Random Access Channel Protocols for Delay Critical M2M Communication over Cellular Networks

With the ever-increasing technological evolution, the current and future generation communication systems are geared towards accommodating Machine to Machine (M2M) communication as a necessary prerequisite for Internet of Things (IoT). Machine Type Communication (MTC) can sustain many promising applications through connecting a huge number of devices into one network. As current studies indicate, the number of devices is escalating at a high rate. Consequently, the network becomes congested because of its lower capacity, when the massive number of devices attempts simultaneous connection through the Random Access Channel (RACH). This results in RACH resource shortage, which can lead to high collision probability and massive access delay. Hence, it is critical to upgrade conventional Random Access (RA) techniques to support a massive number of Machine Type Communication (MTC) devices including Delay-Critical (DC) MTC. This thesis approaches to tackle this problem by modeling and optimising the access throughput and access delay performance of massive random access of M2M communications in Long-Term Evolution (LTE) networks. This thesis investigates the performance of different random access schemes in different scenarios. The study begins with the design and inspection of a group based 2-step Slotted-Aloha RACH (SA-RACH) scheme considering the coexistence of Human-to-Human (H2H) and M2M communication, the latter of which is categorised as: Delay-Critical user equipments (DC-UEs) and Non-Delay-Critical user equipments (NDC-UEs). Next, a novel RACH scheme termed the Priority-based Dynamic RACH (PD-RACH) model is proposed which utilises a coded preamble based collision probability model. Finally, being a key enabler of IoT, Machine Learning, i.e. a Q-learning based approach has been adopted, and a learning assisted Prioritised RACH scheme has been developed and investigated to prioritise a specific user group. In this work, the performance analysis of these novel RACH schemes show promising results compared to that of conventional RACH

Non-coherent slot synchronization techniques for WCDMA systems

This Thesis investigates a host of new synchronization techniques for WCDMA. We assume the presence of more than one base station (BS) (multi-target) in the vicinity of the mobile station (MS), and consider the effects of multipath, Raleigh fading, and different carrier frequency offsets. Through the Thesis, we concentrate on the first stage of the three-stage cell search procedure which is slot synchronization. The slot synchronization stage has been always the most challenging stage since it deals with the largest amount of uncertainty in the cell search, and it determines the timing resolution to the other two stages. We also introduce the concept of using parallel code verification circuits to be added to the state of art pipelined techniques to yield better synchronization results. The received WCDMA synchronization codes are combined in different scenarios according to the proposed non-coherent synchronization technique. The results are compared with recent approaches of combining the WCDMA synchronization codes. The comparison reveals some improvements in the mean synchronization time for some of our rules herein. It also shows superiority of the new rules for different carrier frequency offsets especially at low signal to interference ratios