Soft handover issues in radio resource management for 3G WCDMA networks

PhDMobile terminals allow users to access services while on the move. This unique feature has driven the rapid growth in the mobile network industry, changing it from a new technology into a massive industry within less than two decades. Handover is the essential functionality for dealing with the mobility of the mobile users. Compared with the conventional hard handover employed in the GSM mobile networks, the soft handover used in IS-95 and being proposed for 3G has better performance on both link and system level. Previous work on soft handover has led to several algorithms being proposed and extensive research has been conducted on the performance analysis and parameters optimisation of these algorithms. Most of the previous analysis focused on the uplink direction. However, in future mobile networks, the downlink is more likely to be the bottleneck of the system capacity because of the asymmetric nature of new services, such as Internet traffic. In this thesis, an in-depth study of the soft handover effects on the downlink direction of WCDMA networks is carried out, leading to a new method of optimising soft handover for maximising the downlink capacity and a new power control approach

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

EVEREST IST - 2002 - 00185 : D23 : final report

Deliverable públic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version

LTE Handover performance evaluation based on power budget handover algorithm

LTE (Long Term Evolution) is a fourth generation cellular network technology that provides improved performance related to data rate, coverage and capacity compared to legacy cellular systems. In this context, one of the main goals of LTE is to provide fast and seamless handover from one cell to another to meet a strict delay requirement while simultaneously keeping network management simple. Hence, the decision to trigger a handover is a crucial component in the design process of handover, since the success and the efficiency, to a large extent, depends on the accuracy and timeliness of the decision. The design of an efficient and successful handover requires a careful selection of HO parameters and the optimal setting of these. The LTE standard supports two parameters to trigger the handover and select the target cell: hysteresis margin and Time-to-Trigger (TTT) The research topic of this thesis which is “LTE Handover Performance Evaluation Based on Power Budget Handover Algorithm”, focuses on different combinations or settings of HOM and TTT values to evaluate the handover performance based on Reference Signal Received Power (RSRP) measurement within certain deployment scenarios, such as different UE speeds, system loads and cell sizes. The Power Budget Handover Algorithm (PBHA) picks the best hysteresis and time-to-trigger combinations to evaluate the system performance in terms of number of handovers, signal-to-interference plus noise ratio (SINR), throughput, delay and packet lost for UE's which are about to perform the handover

The new enhancement of UMTS: HSDPA and HSUPA

During the last two decades, the world of the mobile communications grew a lot, as a consequence of the increasing necessity of people to communicate. Now, the mobile communications still need to improve for satisfies the user demands. The new enhancement of UMTS in concrete HSDPA and HSUPA is one of these improvements that the society needs. HSDPA and HSUPA which together are called HSPA, give to the users higher data rates in downlink and uplink. The higher data rates permit to the operators give more different types of services and at the same time with better quality. As a result, people can do several new applications with their mobile terminals like applications that before a computer and internet connection were required, now it is possible to do directly with the mobile terminal. This thesis consists in study these new technologies denominated HSDPA and HSUPA and thus know better the last tendencies in the mobile communications. Also it has a roughly idea about the future tendencies

Service Continuity in 3GPP Mobile Networks

The mobile wireless communication network or cellular network landscape is changing gradually from homogeneous to heterogeneous. Future generation networks are envisioned to be a combination of diverse but complimentary access technologies, like GPRS, WCDMA/HSPA, LTE and WLAN. These technologies came up due to the need to increase capacity in cellular networks and recently driven by the proliferation of smart devices which require a lot of bandwidth. The traditional mechanisms to increase capacity in cellular networks have been to upgrade the networks by, e.g. adding small cells solutions or introducing new radio access technologies to regions requiring lots of capacity, but this has not eradicated the problem entirely. The integration of heterogeneous networks poses some challenges such as allocating resources efficiently and enabling seamless handovers between heterogeneous technologies. One issue which has become apparent recently with the proliferation of different link layer technologies is how service providers can offer a consistent service across heterogeneous networks. Service continuity between different radio access technologies systems is identified as one key research item.  The knowledge of the service offering in current and future networks, and supporting interworking technologies is paramount to understand how service continuity will be realized across different radio access technologies. We investigate the handover procedure and performance in current deployed 3GPP heterogeneous mobile networks (2G, 3G and 4G networks). We perform measurements in the field and the lab and measure the handover latency for User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) applications. The results show that intersystem handover latencies in and across 2G and 3G radio access technologies are too long and have an impact on real time packet switched (PS) real-time services. We also investigate the current proposed interworking and handover schemes in 2G, 3G and 4G networks and present their limitations. We further highlight some open issues that still need to be addressed in order to improve handover performance and provide service continuity across heterogeneous mobile wireless networks such as selection of optimal radio access technology and adaptation of multimedia transmission over heterogeneous technologies. We present the enhancements required to enable service continuity and provide a better quality of user experience. 

Performance evaluation of voice handover between LTE and UMTS

M.Sc.(Eng.), Faculty of Engineering and the Built Environment, 2011The main objective of seamless mobility is to enable mobile users to stay connected while roaming across heterogeneous networks. As cellular networks evolve from the third generation Universal Mobile Telecommunication System (UMTS) to the Long Term Evolution (LTE), a new Evolved Packet Core (EPC) will support heterogeneous radio access networks on the same platform. UMTS provides voice services in the circuit switched domain; while LTE operates in the packet switched domain. Cellular network operators thus face the challenge of providing voice services during initial deployment of LTE due to difficulty in mobility between the two domains. Seamless voice handover between packet switched LTE and the circuit switched UMTS network is therefore an important tool in solving this problem. This report investigates the performance of inter-Radio Access Technology voice handover between LTE and UMTS. The schemes evaluated were Voice Call Continuity (VCC) for UMTS to LTE handover and Single Radio Voice Call Continuity (SRVCC) for LTE to UMTS handover. The performance evaluation was done using mathematical models and equations that were derived for the handover service interruption time. The resulting equations were simulated and the output was analysed and compared with the Third Generation Partnership Project (3GPP) specifications

Gestão comum de recursos rádio em redes sem fios de próxima geração

Mestrado em Electrónica e TelecomunicaçõesA tecnologia de sinais de rádio frequência sobre fibra óptica involve o uso de links ópticos para transportar os sinais desde a unidade central de processamento até aos sites remotos (e vice-versa). A centralização do processamento dos sinais de rádio frequência permite a partilha de equipamentos, alocação dinâmica de recursos e uma manutenção mais simplificada do sistema. Embora o conceito de gestão comum dos recursos rádio tenha despertado grande interesse na comunidade científica em termos da melhor utilização desses recursos e de novos modelos de negócio, a verdade é que a sua implementação não tem sido fácil. A interligação entre diferentes componentes de rede, normalmente localizados em locais diferentes, introduz um grande atraso nas comunicações; por outro lado as implementações proprietárias e a escassez de informação global não satisfazem os requisitos de um ambiente extremamente dinâmico, como é o ambiente wireless. Uma topologia centralizada permite ultrapassar estas contrariedades, disponibilizando uma interligação eficiente entre as entidades locais e comuns de gestão de recursos rádio. Nesta dissertação é apresentada uma nova arquitectura de gestão comum de recursos rádio, baseada no conceito de interligação entre diferentes tecnologias de acesso. Esta arquitectura faz a gestão dos recursos rádio de forma centralizada, onde os sinais rádio chegam sem qualquer pré-processamento. Essa arquitectura é avaliada com a implementação de um algoritmo simples de balanceamento da carga que segue a politica de minimização da interferência e aumento da capacidade. As simulações com duas tecnologias de acesso, quando consideradas separas ou em agregado, mostraram um aumento do débito de pelo menos 51% para o mesmo valor de interferência enquanto que o erro de simbolo decresce pelo menos 20%.Radio over fibre technology involves the use of optical fibre links to distribute radio frequency signals from a central location to remote sites (and viceversa). The centralisation of radio frequency signals processing functions enables equipment sharing, dynamic allocation of resources, and simplified system operation and maintenance. Despite the unquestionable interest concept of common radio resource management from the point of view of resource usage and novel business models, its implementation has not been easy. The interworking between the different local radio resource management entities, usually located on different places will not satisfy the requirements of the wireless dynamic behaviour due to increase of delay in communication process, less information availability and proprietary implementations. A centralised topology can overcome the drawbacks of former wireless systems architecture interconnection by providing an efficient common radio communication flow with the local radio resource management entities. In this thesis a novel common radio resource management architecture is presented based on the concept of inter-working between different technologies. This is a centralised architecture where the radio frequency signals are delivered to the central location through the optical links. The new architecture is evaluated with a common policy that minimises interference while the overall system capacity is increased. The policy is implemented through the load balancing algorithm. The simulations of two radio access technologies when separately and jointly considered show that when the load balancing algorithm is applied the available throughput increases in at least 51% while the symbol error rate decreases at least 20%