Final report on the evaluation of RRM/CRRM algorithms

Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

Bandwidth allocation for wireless multimedia systems.

Chen Chung-Shue.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.Includes bibliographical references (leaves 100-102).Abstracts in English and Chinese.Chapter 1. --- Introduction --- p.1Chapter 1.1 --- Evolution to 3G Mobile --- p.2Chapter 1.1.1 --- First Generation --- p.2Chapter 1.1.2 --- Second Generation --- p.3Chapter 1.1.3 --- Third Generation --- p.3Chapter 1.2 --- UTRA Framework --- p.5Chapter 1.2.1 --- FDD and TDD --- p.6Chapter 1.2.2 --- Channel Spreading --- p.6Chapter 1.2.3 --- OVSF Code Tree --- p.8Chapter 1.3 --- Cellular Concepts --- p.10Chapter 1.3.1 --- System Capacity --- p.10Chapter 1.3.2 --- Multiple Access --- p.11Chapter 1.3.3 --- Resource Management --- p.15Chapter 1.4 --- Organization of the Thesis --- p.16Chapter 2. --- Analysis on Multi-rate Operations --- p.18Chapter 2.1 --- Related Works in Multi-rate Operations --- p.18Chapter 2.1.1 --- Variable Spreading Factor --- p.19Chapter 2.1.2 --- Data Time-multiplexing --- p.20Chapter 2.1.3 --- Multi-carrier Transmission --- p.21Chapter 2.1.4 --- Hybrid TDMA/CDMA --- p.23Chapter 2.2 --- Problems in Multi-rate Operations --- p.24Chapter 2.2.1 --- Conventional CDMA --- p.24Chapter 2.2.2 --- Data Time-multiplexing --- p.25Chapter 2.2.3 --- MC-CDMA --- p.25Chapter 2.2.4 --- TD-CDMA --- p.27Chapter 2.3 --- Multi-user multi-rate Operations --- p.28Chapter 3. --- Bandwidth Allocation --- p.29Chapter 3.1 --- Most Regular Binary Sequence --- p.30Chapter 3.1.1 --- Properties of MRBS --- p.31Chapter 3.1.2 --- Construction of MRCS --- p.32Chapter 3.1.3 --- Zero-one Sequence under MRBS --- p.33Chapter 3.2 --- MRBS in TD-CDMA --- p.35Chapter 3.2.1 --- Time Slot Optimization --- p.36Chapter 3.2.2 --- Sequence Generator --- p.37Chapter 3.3 --- Most Regular Code Sequence --- p.38Chapter 3.3.1 --- Properties of MRCS --- p.38Chapter 3.2.2 --- Construction of MRCS --- p.41Chapter 3.3.3 --- Fraction-valued Sequence under MRCS --- p.42Chapter 3.3.4 --- LCC and UCC --- p.45Chapter 3.4 --- MRCS in WCDMA --- p.46Chapter 3.4.1 --- Spreading Factor Optimization --- p.46Chapter 3.4.2 --- Code Generator --- p.48Chapter 3.4.3 --- Uplink and Downlink --- p.50Chapter 4. --- Multi-access Control --- p.52Chapter 4.1 --- Conflict and Resolution --- p.53Chapter 4.1.1 --- Conflicts in MRBS and MRCS --- p.53Chapter 4.1.2 --- Resolution with Buffering --- p.55Chapter 4.2 --- MRBS Transmission Scheduling --- p.56Chapter 4.2.1 --- Slot Scheduling on MRBS --- p.56Chapter 4.2.2 --- Properties of Scheduling Algorithm --- p.59Chapter 4.2.3 --- Scheduled MRBS --- p.71Chapter 4.3 --- MRCS Transmission Scheduling --- p.73Chapter 4.3.1 --- Slot Scheduling on MRCS --- p.73Chapter 4.3.2 --- Properties of Scheduling Algorithm --- p.75Chapter 4.3.3 --- Scheduled MRBS --- p.76Chapter 4.4 --- Performance Evaluation --- p.78Chapter 4.4.1 --- Simulation on Algorithm --- p.78Chapter 4.4.2 --- Resource Utilization and Delay Bound --- p.79Chapter 4.4.3 --- Blocking Model and System Capacity --- p.80Chapter 4.4.4 --- Numerical Analysis --- p.86Chapter 5. --- Conclusions and Future works --- p.92Appendix A --- p.94Appendix B --- p.98Bibliography --- p.10

Capacity and Throughput Optimization in Multi-cell 3G WCDMA Networks

User modeling enables in the computation of the traffic density in a cellular network, which can be used to optimize the placement of base stations and radio network controllers as well as to analyze the performance of resource management algorithms towards meeting the final goal: the calculation and maximization of network capacity and throughput for different data rate services. An analytical model is presented for approximating the user distributions in multi-cell third generation wideband code division multiple access (WCDMA) networks using 2-dimensional Gaussian distributions by determining the means and the standard deviations of the distributions for every cell. This model allows for the calculation of the inter-cell interference and the reverse-link capacity of the network. An analytical model for optimizing capacity in multi-cell WCDMA networks is presented. Capacity is optimized for different spreading factors and for perfect and imperfect power control. Numerical results show that the SIR threshold for the received signals is decreased by 0.5 to 1.5 dB due to the imperfect power control. The results also show that the determined parameters of the 2-dimensional Gaussian model match well with traditional methods for modeling user distribution. A call admission control algorithm is designed that maximizes the throughput in multi-cell WCDMA networks. Numerical results are presented for different spreading factors and for several mobility scenarios. Our methods of optimizing capacity and throughput are computationally efficient, accurate, and can be implemented in large WCDMA networks

Resource Allocation in Ad Hoc Networks

Unlike the centralized network, the ad hoc network does not have any central administrations and energy is constrained, e.g. battery, so the resource allocation plays a very important role in efficiently managing the limited energy in ad hoc networks. This thesis focuses on the resource allocation in ad hoc networks and aims to develop novel techniques that will improve the network performance from different network layers, such as the physical layer, Medium Access Control (MAC) layer and network layer. This thesis examines the energy utilization in High Speed Downlink Packet Access (HSDPA) systems at the physical layer. Two resource allocation techniques, known as channel adaptive HSDPA and two-group HSDPA, are developed to improve the performance of an ad hoc radio system through reducing the residual energy, which in turn, should improve the data rate in HSDPA systems. The channel adaptive HSDPA removes the constraint on the number of channels used for transmissions. The two-group allocation minimizes the residual energy in HSDPA systems and therefore enhances the physical data rates in transmissions due to adaptive modulations. These proposed approaches provide better data rate than rates achieved with the current HSDPA type of algorithm. By considering both physical transmission power and data rates for defining the cost function of the routing scheme, an energy-aware routing scheme is proposed in order to find the routing path with the least energy consumption. By focusing on the routing paths with low energy consumption, computational complexity is significantly reduced. The data rate enhancement achieved by two-group resource allocation further reduces the required amount of energy per bit for each path. With a novel load balancing technique, the information bits can be allocated to each path in such that a way the overall amount of energy consumed is minimized. After loading bits to multiple routing paths, an end-to-end delay minimization solution along a routing path is developed through studying MAC distributed coordination function (DCF) service time. Furthermore, the overhead effect and the related throughput reduction are studied. In order to enhance the network throughput at the MAC layer, two MAC DCF-based adaptive payload allocation approaches are developed through introducing Lagrange optimization and studying equal data transmission period

Heterogeneous Vehicular Networks

This brief examines recent developments in the Heterogeneous Vehicular NETworks (HETVNETs), integrating cellular networks with Dedicated Short-Range Communication (DSRC) for meeting the communications requirements of the Intelligent Transport System (ITS)services. Along with a review of recent literature, a unified framework of the HetVNET is presented. The brief focuses on introducing efficient MAC mechanisms for vehicular communications, including channel access protocols, broadcast/multicast protocols, the location-based channel congestion control scheme and the content-based resource allocation scheme. The cooperative communication between vehicles is discussed. This brief concludes with a discussion on future research directions, and provides the readers with useful insights into the future designs in the HetVNETs, to motivate new ideas for performance improvements in vehicular networks

Contribución a la planificación sistémica de redes móviles 4G

El objetivo de esta Tesis consiste en el diseño, implementación y prueba de algoritmos, tanto convencionales –utilizados actualmente en la industria– como otros novedosos basados en Computación Evolutiva, que constituyan una contribución novedosa a la planificación sistémica de redes móviles LTE. En particular, se centra en el dimensionamiento estratégico de la red de acceso de LTE, debido a que constituye aproximadamente el 60% de la inversión total, e incluso una parte más elevada de los gastos OPEX (operating expense). La Tesis establece una novedosa propuesta para el problema de asignación o asociación de usuarios a eNBs (evolved NBs) en LTE. La contribución es este aspecto es doble: por un lado, se plantea un nuevo método para asociar N_U usuarios a N_B eNBs en redes LTE. Consiste éste en modelar la asociación usuario-eNB como un problema de optimización combinatoria en el que la función a minimizar es una métrica novedosa conocida como “Tiempo de descarga total del sistema” –Download Time of the complete System (DTS). La minimización de DTS se traduce en una asignación de usuarios a celdas más eficiente que la que se consigue con métodos convencionales como el basado en maximizar CQI (Channel Quality Indicator) o en balanceo de carga (Load Balancing –LB–). Permite la asignación de usuarios desde celdas que, de otra forma, estarían sobrecargadas a otras con menos carga. Esto tiene un doble beneficio, tanto para el operador como para los usuarios. Por una parte, ayudar al operador de red a utilizar sus recursos de una manera más equilibrada y rentable. Por otra parte, la estrategia propuesta reduce el tiempo de descarga para la mayoría de los usuarios, e introduce cierta equidad en el reparto de recursos. La minimización de DTS es un problema de gran complejidad computacional. Ésta es justamente la razón que ha motivado la segunda contribución de esta Tesis: abordar el problema de la minimización de DTS mediante un algoritmo evolutivo (EA). El aspecto más interesante del EA propuesto es la forma en la que se realiza la codificación de las soluciones (asignaciones usuario-celda) candidatas. El cromosoma es un vector de dimensión N_U en el que cada elemento representa un usuario. El elemento en la posición j contiene cierta información sobre el usuario u_j. Esa información es un número entero que representa a qué eNB de los N_U disponibles se ha asignado dicho usuario. Los operadores de mutación, cruce y selección se han diseñado para que puedan trabajar con esta codificación. El operador de cruce, en particular, es un torneo de todos contra todos. El otro aspecto novedoso de la implementación del algoritmo evolutivo propuesto se encuentra en la población inicial. Como se tiene información de una solución sub-óptima del problema (la proporcionada por el método convencional basado en CQI –que asigna un usuario al eNB para el cual tiene mejor CQI–), se incluye ésta en la población inicial, y el resto de los individuos se genera, básicamente, aplicando los operadores de mutación y cruce sobre esa solución. En cualquier caso, la solución encontrada (asociación de cada usuario a un eNB) es mejor (menor DTS) que la asignación realizada con métodos convencionales. El segundo conjunto de contribuciones de la Tesis consiste en el diseño de una herramienta de planificación estratégica LTE, centrada en el proceso de dimensionado de red en un entorno multiusuario y multiservicio, y en la que se ha integrado en módulo EA de asociación usuario-eNB. Mediante esta integración, dicha herramienta, permite realizar comparativas entre el enfoque propuesto de asignación en base al EA y otros métodos convencionales, integrados en la herramienta, como los basados en CQI y en LB. En concreto, la herramienta tiene (1) una parametrización sencilla y eficaz de los múltiples parámetros de entrada y de la ubicación inicial de los eNB, que (2) permite simular un entorno multi-servicio y multi-usuario, empleando (3) diferentes algoritmos de asociación usuario-eNB –como el propuesto en la Tesis– y (4) varios algoritmos de scheduling, de forma que (5) se garantiza el cumplimiento del requisito de Velocidad de Descarga Mínima de cada servicio. Para cumplir los requisitos (1)–(5), la herramienta calcula la velocidad media de los servicios ofertados, teniendo en cuenta los tiempos de descarga de cada uno de los usuarios. Si con el número de eNB, calculados previamente, se cumple el requisito de velocidad demandada por los distintos servicios simulados, entonces se dará́ por válido dicho valor. En caso de incumplimiento, se añaden eNBs de forma iterativa hasta cumplir el requisito anterior. Ninguna de las herramientas disponibles en el mercado, tanto comerciales como basadas en software libre, es capaz de cumplir estos requisitos. Para cuantificar en qué medida la herramienta desarrollada, en general, y nuestra propuesta de asignación usuario-celda, en particular, son útiles en el dimensionamiento de LTE, se han llevado a cabo un conjunto amplio y variado de simulaciones, en diferentes escenarios realistas, tanto urbano como urbano denso, y se han comparado con dos métodos de asignación usuario-celda convencionales basados en CQI y en LB. Estos experimentos muestran que el método propuesto supera claramente a los convencionales, especialmente en áreas urbanas y urbana densa (entornos donde la asignación es más crítica en términos de capacidad) con macro-celdas de LTE, e incluso, en escenarios que modelan redes heterogéneas y ultra densas. La herramienta y los algoritmos que se proponen en esta tesis pueden ayudar a los operadores a mejorar sus diseños previos al despliegue y a cuantificar la mejora potencial que se conseguiría en la red al añadir un nuevo nodo. Los resultados de la investigación realizada en la Tesis se han publicando en varias revistas y congresos internacionales

Efficient Radio Resource Allocation Schemes and Code Optimizations for High Speed Downlink Packet Access Transmission

An important enhancement on the Wideband Code Division Multiple Access (WCDMA) air interface of the 3G mobile communications, High Speed Downlink Packet Access (HSDPA) standard has been launched to realize higher spectral utilization efficiency. It introduces the features of multicode CDMA transmission and Adaptive Modulation and Coding (AMC) technique, which makes radio resource allocation feasible and essential. This thesis studies channel-aware resource allocation schemes, coupled with fast power adjustment and spreading code optimization techniques, for the HSDPA standard operating over frequency selective channel. A two-group resource allocation scheme is developed in order to achieve a promising balance between performance enhancement and time efficiency. It only requires calculating two parameters to specify the allocations of discrete bit rates and transmitted symbol energies in all channels. The thesis develops the calculation methods of the two parameters for interference-free and interference-present channels, respectively. For the interference-present channels, the performance of two-group allocation can be further enhanced by applying a clustering-based channel removal scheme. In order to make the two-group approach more time-efficient, reduction in matrix inversions in optimum energy calculation is then discussed. When the Minimum Mean Square Error (MMSE) equalizer is applied, optimum energy allocation can be calculated by iterating a set of eigenvalues and eigenvectors. By using the MMSE Successive Interference Cancellation (SIC) receiver, the optimum energies are calculated recursively combined with an optimum channel ordering scheme for enhancement in both system performance and time efficiency. This thesis then studies the signature optimization methods with multipath channel and examines their system performances when combined with different resource allocation methods. Two multipath-aware signature optimization methods are developed by applying iterative optimization techniques, for the system using MMSE equalizer and MMSE precoder respectively. A PAM system using complex signature sequences is also examined for improving resource utilization efficiency, where two receiving schemes are proposed to fully take advantage of PAM features. In addition by applying a short chip sampling window, a Singular Value Decomposition (SVD) based interference-free signature design method is presented