Call admission control for interactive multimedia satellite networks.

Master of Science in Engineering (Electronic). University of KwaZulu-Natal, Durban 2015.Satellite communication has become an integral component of global access communication network due mainly to its ubiquitous coverage, large bandwidth and ability to support for large numbers of users over fixed and mobile devices. However, the multiplicity of multimedia applications with diverse requirements in terms of quality of service (QoS) poses new challenges in managing the limited and expensive resources. Furthermore, the time-varying nature of the propagation channel due to atmospheric and environmental effects also poses great challenges to effective utilization of resources and the satisfaction of users’ QoS requirements. Efficient radio resource management (RRM) techniques such as call admission control (CAC) and adaptive modulation and coding (AMC) are required in order to guarantee QoS satisfaction for user established connections and realize maximum and efficient utilization of network resources. In this work, we propose two CAC policies for interactive satellite multimedia networks. The two policies are based on efficient adaptation of transmission parameters to the dynamic link characteristics. In the first policy which we refer to as Gaussian Call Admission Control with Link Adaptation (GCAC-LA), we invoke the central limit theorem to statistically multiplex rate based dynamic capacity (RBDC) connections and obtain an aggregate bandwidth and required capacity for the multiplex. Adaptive Modulation and Coding (AMC) is employed for transmission over the time-varying wireless channel of the return link of an interactive satellite network. By associating users’ channel states to particular transmission parameters, the amount of resources required to satisfy user connection requirements in each state is determined. Thus the admission control policy considers in its decision, the channel states of all existing and new connections. The performance of the system is investigated by simulation and the results show that AMC significantly improves the utilization and call blocking performance by more than twice that of a system without link adaptation. In the second policy, a Game Theory based CAC policy with link adaptation (GTCAC-LA) is proposed. The admission of a new user connection under the GTCAC-LA policy is based on a non-cooperative game that is played between the network (existing user connections) and the new connection. A channel prediction scheme that predicts the rain attenuation on the link in successive intervals of time is also proposed. This determines the current resource allocation for every source at any point in time. The proposed game is played each time a new connection arrives and the strategies adopted by players are based on utility function, which is estimated based on the required capacity and the actual resources allocated. The performance of the CAC policy is investigated for different prediction intervals and the results show that multiple interval prediction scheme shows better performance than the single interval scheme. Performance of the proposed CAC policies indicates their suitability for QoS provisioning for traffic of multimedia connections in future 5G networks

QoS management in UMTS terrestrial radio access FDD networks

This work investigates the role and importance of some of the key aspects of QoS planning, provisioning, monitoring and optimisation (QoS Management) for UMTS Terrestrial Radio Access (UTRA) FDD networks within the framework of the 3rd Generation Partnership Project (3GPP). Firstly, the differences between Quality of end user Experience (QoE) and Quality of Service (QoS) are explained. This is followed by a review of 3GPP requirements for QoS concept and architecture. Then all models and the main assumptions in this dissertation are presented. Based on these, original QoS mechanisms in the radio access network domain, means and methods for QoS provisioning, planning, monitoring and "optimisation" are discussed. Simulation results showed substantial spectral efficiency gains provided by service (or user) differentiation in UTRAN by means of priorities and differentiated parameter settings. When appropriately configured, the proposed QoS mechanisms can greatly reduce the need for bandwidth. Performance results proved also the proposed virtual time simulator to be an appropriate tool for service driven WCDMA radio interface dimensioning and detailed radio network planning. It is also shown that measuring QoS performance by a proper classification of counters (and or gauges), based on a particular subset of radio access bearer attributes, is a promising technique for assessing performances of service applications through WCDMA networks. With this new method there is no need to trace upper layer protocols at different interfaces or dumping data in mobile terminals. The proposed metrics allow operators to measure the bandwidth required for robust statistical reliability, to assess and exploit statistical sharing of resources, to configure QoS functions effectively, and to monitor QoE. The application of the proposed technique is not limited to the WCDMA Radio Network Subsystem (RNS), yet it can be deployed in any radio access and packet core network supporting mapping of performance indicators onto a particular subset of QoS attributes. Finally, in order to maximise the performance of the available services in UTRAN, at a given QoE, simulation results showed clear needs for the network administrator to adapt the parameter settings to diverse input application traffic conditions and the proposed genetic approach to be an appropriate solution space search algorithm for this purpose.reviewe

Optimal reception of 64 Quadrature Amplitude Modulation in High-Speed Downlink Packet Access

HSDPA on vuonna 2002 UMTS-verkkoihin lisätty ominaisuus. Sen avulla laskevalla siirtotiellä mobiililaitteiden huippunopeudeksi saadaan 14.4 megabittiä sekunnissa. Vuonna 2007 standardoitiin uusia HSDPA-ominaisuuksia, niiden mukana uusi modulaatiotyyppi 64-QAM. 64-QAM:in avulla suurin siirtonopeus saadaan nostettua 21.6:n megabittiin sekunnissa. Sekä lähettimiä että vastaanottimia on päivitettävä uuden modulaatiotyypin tukemiseksi. Vastaanottopäässä signaalin amplitudi täytyy ensin estimoida tarkasti jotta signaali voidaan vastaanottaa oikein. Signaali pitää vielä tämän jälkeen demoduloida riittävällä tarkkuudella. Samankaltaisia algoritmeja on käytetty jo vanhemmissa HSDPA-versioissa, mutta 64-QAM on huomattavasti herkempi virheille. Tässä työssä amplitudiestimointia ja demodulointia varten testattiin kolmea eri algoritmivaihtoehtoa. Algoritmien vertailuun käytettiin fyysisen kerroksen HSDPA-simulaattoria, jossa käytettiin standardin mukaisia realistisia parametreja. Lopputuloksena yksiselitteisesti parasta tapaa estimoida amplitudia ei löytynyt, mutta kaksi ehdokkaista osoitti hyviä ominaisuuksia. Parhaaksi demodulointialgoritmiksi osoittautui yksinkertaistettu versio optimaalisesta MAP-ilmaisimesta, joka hoitaa demoduloinnin yksiulotteisesti.High-speed downlink packet access (HSDPA) is a feature introduced to the universal mobile telecommunications system (UMTS) in 2002. It allows data rates of up to 14.4 Mbps in the downlink. In 2007 new features were standardized to HSDPA, including 64 Quadrature Amplitude Modulation (64-QAM). 64-QAM allows more data to be transmitted on the same bandwidth, increasing the HSDPA peak data rate to 21.6 Mbps. Transmitters and receivers must be updated with new algorithms to support this new modulation type. On the terminal side the amplitude of the signal must first be precisely estimated so that it can be demodulated correctly. Then a demodulation algorithm with good enough accuracy must be applied. Similar algorithms were already used with older HSDPA versions, but 64-QAM is much more sensitive to errors. In this thesis, three amplitude estimation and three demodulation algorithm candidates were considered. A physical layer HSDPA simulator with realistic parameters was used to compare the algorithms. There was no clear winner when selecting the best way to estimate the amplitude, but two of the algorithm candidates proved to be better than the third. The best demodulation algorithm for practical applications turned out to be a simplified MAP optimum detector that models the demodulation as a one-dimensional problem

Transport formats in UMTS Radio Network Controller's software implementation

Radioresurssien hallinta (RRM) on olennainen osa kolmannen sukupolven WCDMA-radioverkkojen kehitystä. Suurin osa radioresurssien hallinnasta toteutetaan radioverkko-ohjaimessa (RNC), joka sijoittuu verkossa tukiasemien ja runkoverkon väliin. Siirtoformaatit (engl. transport format) määrittävät, miten tietoa välitetään fyysisen ja siirtoyhteyskerroksen välillä. Nämä parametrit kontrolloivat, kuinka paljon dataa siirretään siirtokanavalla ja miten fyysinen kerros koodaa tämän datan. Yhdelle siirtokanavalle liitettyä siirtoformaattien joukkoa kutsutaan Transport Format Setiksi (TFS) ja tietyllä ajanhetkellä voimassa olevien siirtoformaattien kombinaatiota Transport Format Combination Setiksi (TFCS). Näiden parametrien takana oleva teoria ja niiden käyttö verkossa ovat tämän diplomityön pääaiheita. Yleisen teoriaosuuden jälkeen työ keskittyy siirtoformaatteihin liittyvään ohjelmistototeutukseen RNC:ssä. Työssä tutkittu ohjelmalohko laskee TFS- ja TFCS-parametrit yhdelle radioresursseiltaan kontrolloidulle RRC-yhteydelle. Toteutuksen oleelliset osat esitellään ja tähän liittyvän ohjelmakoodin tehokkuutta ja ylläpidettävyyttä parannetaan. Nykyisen toteutuksen tutkimisen ja parantamisen lisäksi myös näiden toiminnallisuuksien modulitestaus toteutettiin osana tätä diplomityötä. Valitut testauskäytännöt ja suunnitellut testitapaukset analysoitiin tehokkuus- ja kattavuusominaisuuksiltaan. Tämän jälkeen nykytoteutuksen katsottiin olevan täysin toimiva lähetettäväksi ylemmän tason testausta varten. Myös toteutukseen tehtyjen parannusten todettiin olevan toimivia. Tämän diplomityön tuloksena ohjelmalohkon tutkitut ominaisuudet ovat nykyisellään täysin toimivia ja entistä paremmin ylläpidettäviä. Kehitystyö tarkastellun ohjelmalohkon parissa jatkuu kuitenkin myös tämän työn valmistumisen jälkeen.Radio Resource Management (RRM) is an essential topic when 3G WCDMA networks are being developed. The majority of RRM related tasks are performed in the Radio Network Controller (RNC) which is situated between the base stations and the core network. Transport format parameters define how data is exchanged between the physical layer and the data link layer. These parameters control how much data is transferred on a transport channel and how the data is coded by the physical layer. A set of transport formats associated to a transport channel is called a Transport Format Set (TFS) and the combination of currently valid transport formats is called a Transport Format Combination Set (TFCS). The theory and the usage of these parameters is the main topic in this thesis. After the general theory part, this paper focuses on transport format related implementation in a real RNC software. The program block under investigation performs TFS and TFCS calculation for one Radio Resource Control (RRC) connection. The essential parts of the implementation are presented and the related code is improved for better efficiency and better maintainability. In addition to investigating and improving the current implementation, also module testing of these features was carried out as a part of this thesis. The selected testing methods and designed test cases were analysed for their efficiency and code coverage properties. After this, the implementation was considered fully functional to be delivered to higher level testing. Also the improvements made to the implementation were discovered workable. As a result of this thesis, the observed features of the program block are now fully functional and better maintainable than before. However, development work with the observed program block will continue also after the completion of this thesis

Modeling and resource management of SDR Clouds

This TFC models software-defined radio (SDR) processing chains and manages their distributed execution on SDR clouds. We present models of UMTS processing chains for different bit rates. These chains model the digital processing requirements of a transmitter and receiver in the base station. Therefore, we analyze the users multiplexing in WCDMA because it has implications on the computing resources and its correct management. We propose different management strategies, implement one and evaluate its correct functionality. The solution we promote is based on defining a ghost function that captures the data flow dependencies between the chip-level and bit-level processing part of WCDMA. The chip-level processing chain processes signals of multiple users, whereas the bit-level processing chain processes a single user’s signal. The simulations are executed with an appropriate user load, which is part of our investigation. For the development of this TFC we are provided of a mapping algorithm for the computing resource management in a simulation environment. This algorithm runs a trellis evaluating the costs of the different paths during the mapping process of the signal processing blocks of a processing chain to the distributed computing resources of the multiprocessors platform

3G Wideband CDMA : packet-based optimisation for high data-rate downlink transmission

A third generation (3G) of mobile communication systems, based on Wideband CDMA, are intended to offer high-speed packet-based services. Network operators wish to maximise the throughput in the downlink of3G systems, which requires efficient allocation ofresources. This thesis considers the problem ofmaximising throughput in an interference dominated channel. Cooperative broadcasting is a theoretical technique to mitigate this problem. Its implementation in practical systems requires efficient resource allocati.on to maximise the thr(oughput whilst meeting system and user-imposed constramts. A resource allocation approach is presented for implementing cooperative broadcasting. Users are paired and a teclmique for allocating resources between the pair is developed. Then, a method for pairing the users is considered. Simulation results are presented, which show a throughput improvement over existing resource allocation approaches. The problem ofcontrolling the distribution ofrandomly arriving data to meet the resource allocation specifications is examined. A single-threshold buffer is proposed, which requires fewer calculations than an existing double-threshold buffer. Simulation results are presented which show a throughput improvement may be realised, greater than that which would achievable using other rate control schemes. Cooperative broadcasting may lead to transmissions to some users being allocated low power. When full channel infonnation is available at the transmitter, a water filling solution may be used to maximise capacity. However, when combined with buffer management, erasure may result. This erasure may be overcome using an erasure protection code. Such a code is examined. When combined with Turbo coding, ajoint detector may be used for providing error and erasure protection. Analysis ofthis detector shows a lower limit on the error rate, dependent on the probability of erasure. Simulation results show that using this approach the error rate is significantly improved. This code can then be used to increase capacity, whilst achieving low error rates.Imperial Users onl

Adaptive Communications for Next Generation Broadband Wireless Access Systems

Un dels aspectes claus en el disseny i gestió de les xarxes sense fils d'accés de banda ampla és l'ús eficient dels recursos radio. Des del punt de vista de l'operador, l'ample de banda és un bé escàs i preuat que s´ha d'explotar i gestionar de la forma més eficient possible tot garantint la qualitat del servei que es vol proporcionar. Per altra banda, des del punt de vista del usuari, la qualitat del servei ofert ha de ser comparable al de les xarxes fixes, requerint així un baix retard i una baixa pèrdua de paquets per cadascun dels fluxos de dades entre la xarxa i l'usuari. Durant els darrers anys s´han desenvolupat nombroses tècniques i algoritmes amb l'objectiu d'incrementar l'eficiència espectral. Entre aquestes tècniques destaca l'ús de múltiples antenes al transmissor i al receptor amb l'objectiu de transmetre diferents fluxos de dades simultaneament sense necessitat d'augmentar l'ample de banda. Per altra banda, la optimizació conjunta de la capa d'accés al medi i la capa física (fent ús de l'estat del canal per tal de gestionar de manera optima els recursos) també permet incrementar sensiblement l'eficiència espectral del sistema.L'objectiu d'aquesta tesi és l'estudi i desenvolupament de noves tècniques d'adaptació de l'enllaç i gestió dels recursos ràdio aplicades sobre sistemes d'accés ràdio de propera generació (Beyond 3G). Els estudis realitzats parteixen de la premissa que el transmisor coneix (parcialment) l'estat del canal i que la transmissió es realitza fent servir un esquema multiportadora amb múltiples antenes al transmisor i al receptor. En aquesta tesi es presenten dues línies d'investigació, la primera per casos d'una sola antenna a cada banda de l'enllaç, i la segona en cas de múltiples antenes. En el cas d'una sola antena al transmissor i al receptor, un nou esquema d'assignació de recursos ràdio i priorització dels paquets (scheduling) és proposat i analitzat integrant totes dues funcions sobre una mateixa entitat (cross-layer). L'esquema proposat té com a principal característica la seva baixa complexitat i que permet operar amb transmissions multimedia. Alhora, posteriors millores realitzades per l'autor sobre l'esquema proposat han permès també reduir els requeriments de senyalització i combinar de forma óptima usuaris d'alta i baixa mobilitat sobre el mateix accés ràdio, millorant encara més l'eficiència espectral del sistema. En cas d'enllaços amb múltiples antenes es proposa un nou esquema que combina la selecció del conjunt optim d'antenes transmissores amb la selecció de la codificació espai- (frequència-) temps. Finalment es donen una sèrie de recomanacions per tal de combinar totes dues línies d'investigació, així con un estat de l'art de les tècniques proposades per altres autors que combinen en part la gestió dels recursos ràdio i els esquemes de transmissió amb múltiples antenes.Uno de los aspectos claves en el diseño y gestión de las redes inalámbricas de banda ancha es el uso eficiente de los recursos radio. Desde el punto de vista del operador, el ancho de banda es un bien escaso y valioso que se debe explotar y gestionar de la forma más eficiente posible sin afectar a la calidad del servicio ofrecido. Por otro lado, desde el punto de vista del usuario, la calidad del servicio ha de ser comparable al ofrecido por las redes fijas, requiriendo así un bajo retardo y una baja tasa de perdida de paquetes para cada uno de los flujos de datos entre la red y el usuario. Durante los últimos años el número de técnicas y algoritmos que tratan de incrementar la eficiencia espectral en dichas redes es bastante amplio. Entre estas técnicas destaca el uso de múltiples antenas en el transmisor y en el receptor con el objetivo de poder transmitir simultáneamente diferentes flujos de datos sin necesidad de incrementar el ancho de banda. Por otro lado, la optimización conjunta de la capa de acceso al medio y la capa física (utilizando información de estado del canal para gestionar de manera óptima los recursos) también permite incrementar sensiblemente la eficiencia espectral del sistema.El objetivo de esta tesis es el estudio y desarrollo de nuevas técnicas de adaptación del enlace y la gestión de los recursos radio, y su posterior aplicación sobre los sistemas de acceso radio de próxima generación (Beyond 3G). Los estudios realizados parten de la premisa de que el transmisor conoce (parcialmente) el estado del canal a la vez que se considera que la transmisión se realiza sobre un sistema de transmisión multiportadora con múltiple antenas en el transmisor y el receptor. La tesis se centra sobre dos líneas de investigación, la primera para casos de una única antena en cada lado del enlace, y la segunda en caso de múltiples antenas en cada lado. Para el caso de una única antena en el transmisor y en el receptor, se ha desarrollado un nuevo esquema de asignación de los recursos radio así como de priorización de los paquetes de datos (scheduling) integrando ambas funciones sobre una misma entidad (cross-layer). El esquema propuesto tiene como principal característica su bajo coste computacional a la vez que se puede aplicar en caso de transmisiones multimedia. Posteriores mejoras realizadas por el autor sobre el esquema propuesto han permitido también reducir los requisitos de señalización así como combinar de forma óptima usuarios de alta y baja movilidad. Por otro lado, en caso de enlaces con múltiples antenas en transmisión y recepción, se presenta un nuevo esquema de adaptación en el cual se combina la selección de la(s) antena(s) transmisora(s) con la selección del esquema de codificación espacio-(frecuencia-) tiempo. Para finalizar, se dan una serie de recomendaciones con el objetivo de combinar ambas líneas de investigación, así como un estado del arte de las técnicas propuestas por otros autores que combinan en parte la gestión de los recursos radio y los esquemas de transmisión con múltiples antenas.In Broadband Wireless Access systems the efficient use of the resources is crucial from many points of views. From the operator point of view, the bandwidth is a scarce, valuable, and expensive resource which must be exploited in an efficient manner while the Quality of Service (QoS) provided to the users is guaranteed. On the other hand, a tight delay and link quality constraints are imposed on each data flow hence the user experiences the same quality as in fixed networks. During the last few years many techniques have been developed in order to increase the spectral efficiency and the throughput. Among them, the use of multiple antennas at the transmitter and the receiver (exploiting spatial multiplexing) with the joint optimization of the medium access control layer and the physical layer parameters.In this Ph.D. thesis, different adaptive techniques for B3G multicarrier wireless systems are developed and proposed focusing on the SS-MC-MA and the OFDM(A) (IEEE 802.16a/e/m standards) communication schemes. The research lines emphasize into the adaptation of the transmission having (Partial) knowledge of the Channel State Information for both; single antenna and multiple antenna links. For single antenna links, the implementation of a joint resource allocation and scheduling strategy by including adaptive modulation and coding is investigated. A low complexity resource allocation and scheduling algorithm is proposed with the objective to cope with real- and/or non-real- time requirements and constraints. A special attention is also devoted in reducing the required signalling. However, for multiple antenna links, the performance of a proposed adaptive transmit antenna selection scheme jointly with space-time block coding selection is investigated and compared with conventional structures. In this research line, mainly two optimizations criteria are proposed for spatial link adaptation, one based on the minimum error rate for fixed throughput, and the second focused on the maximisation of the rate for fixed error rate. Finally, some indications are given on how to include the spatial adaptation into the investigated and proposed resource allocation and scheduling process developed for single antenna transmission

Convergence of packet communications over the evolved mobile networks; signal processing and protocol performance

In this thesis, the convergence of packet communications over the evolved mobile networks is studied. The Long Term Evolution (LTE) process is dominating the Third Generation Partnership Project (3GPP) in order to bring technologies to the markets in the spirit of continuous innovation. The global markets of mobile information services are growing towards the Mobile Information Society. The thesis begins with the principles and theories of the multiple-access transmission schemes, transmitter receiver techniques and signal processing algorithms. Next, packet communications and Internet protocols are referred from the IETF standards with the characteristics of mobile communications in the focus. The mobile network architecture and protocols bind together the evolved packet system of Internet communications to the radio access network technologies. Specifics of the traffic models are shortly visited for their statistical meaning in the radio performance analysis. Radio resource management algorithms and protocols, also procedures, are covered addressing their relevance for the system performance. Throughout these Chapters, the commonalities and differentiators of the WCDMA, WCDMA/HSPA and LTE are covered. The main outcome of the thesis is the performance analysis of the LTE technology beginning from the early discoveries to the analysis of various system features and finally converging to an extensive system analysis campaign. The system performance is analysed with the characteristics of voice over the Internet and best effort traffic of the Internet. These traffic classes represent the majority of the mobile traffic in the converged packet networks, and yet they are simple enough for a fair and generic analysis of technologies. The thesis consists of publications and inventions created by the author that proposed several improvements to the 3G technologies towards the LTE. In the system analysis, the LTE showed by the factor of at least 2.5 to 3 times higher system measures compared to the WCDMA/HSPA reference. The WCDMA/HSPA networks are currently available with over 400 million subscribers and showing increasing growth, in the meanwhile the first LTE roll-outs are scheduled to begin in 2010. Sophisticated 3G LTE mobile devices are expected to appear fluently for all consumer segments in the following years

Performance evaluation of VoIP and web services in HSDPA

During the last years, the mobile communications market in the western developed countries has reached a standstill, with a market penetration higher than 100% in most countries such as, Spain 115%, United Kingdom 120% and Italy with more than 150%. So the network operators have focused their strategy in moving into a new market still developing, the data, that could help the operators to increase their saturated income. The solution mostly adopted by the operators is to offer the mobile broadband offering flat rate schemes to the customers for a monthly fee. The mobile broadband appeals to wide range of users, such as corporate users and especially to students which give them the liberty to access internet across different locations such as university, cafe or shared accommodation. That creates a set of challenges to the operators having to improve their network in order to cope with this huge new demand for high-speed data, to successfully satisfy these requirements, Third Generation networks must support high user data rates, especially on the downlink direction of the communication path due to its heavier load. For these reason, the 3GPP standardized in Release 5 the technology HSDPA (High Speed Downlink Packet Access). The HSDPA provides a cost effective solution to provide high-speed data to the customers specially focused to increase the overall cell capacity thanks to the fact that the resources are shared among the users. This project has consisted on the design of a HSDPA simulator and on the evaluation of the performance of VoIP and web browsing traffic in HSDPA. The idea of this project started on an industrial placement in Orange UK, in the department of Access Network. Between other tasks the CQI (Channel Quality Information) were modelled using samples taken from the live network. In order to do a more theoretical analysis and make use of the CQI modelling, after the placement, the design of the complete simulator has been made under the direction of Professor Ferran Casadevall. The objective of this project is then to simulate an HSDPA cell in different conditions, specially focused in different cell loading conditions such as: · Different number of users, up to 100 users per cell. · Different traffic profiles, choosing between VoIP and web users. Once the simulations have been carried out, the results have been analysed in detail, offering figures and facts of how the throughput and the traffic delay changes with different load conditions. As both the VoIP and web traffic have different thresholds of maximum delay defined by international entities, the simulations could be used to asses to define, the maximum number of HSPDA users in cell. This will help to capacity planners to decide the rollout strategy, based on the simulation results. This project has been developed with the tool Matlab. This tool has been chosen because it allows an effective code development and at the same time it is very useful to produce graphics and to compute difficult numerical calculations