Energy-efficient vertical handover parameters, classification and solutions over wireless heterogeneous networks: a comprehensive survey

In the last few decades, the popularity of wireless networks has been growing dramatically for both home and business networking. Nowadays, smart mobile devices equipped with various wireless networking interfaces are used to access the Internet, communicate, socialize and handle short or long-term businesses. As these devices rely on their limited batteries, energy-efficiency has become one of the major issues in both academia and industry. Due to terminal mobility, the variety of radio access technologies and the necessity of connecting to the Internet anytime and anywhere, energy-efficient handover process within the wireless heterogeneous networks has sparked remarkable attention in recent years. In this context, this paper first addresses the impact of specific information (local, network-assisted, QoS-related, user preferences, etc.) received remotely or locally on the energy efficiency as well as the impact of vertical handover phases, and methods. It presents energy-centric state-of-the-art vertical handover approaches and their impact on energy efficiency. The paper also discusses the recommendations on possible energy gains at different stages of the vertical handover process

Energy-efficient vertical handover parameters, classification and solutions over wireless heterogeneous networks: a comprehensive survey

In the last few decades, the popularity of wireless networks has been growing dramatically for both home and business networking. Nowadays, smart mobile devices equipped with various wireless networking interfaces are used to access the Internet, communicate, socialize and handle short or long-term businesses. As these devices rely on their limited batteries, energy-efficiency has become one of the major issues in both academia and industry. Due to terminal mobility, the variety of radio access technologies and the necessity of connecting to the Internet anytime and anywhere, energy-efficient handover process within the wireless heterogeneous networks has sparked remarkable attention in recent years. In this context, this paper first addresses the impact of specific information (local, network-assisted, QoS-related, user preferences, etc.) received remotely or locally on the energy efficiency as well as the impact of vertical handover phases, and methods. It presents energy-centric state-of-the-art vertical handover approaches and their impact on energy efficiency. The paper also discusses the recommendations on possible energy gains at different stages of the vertical handover process

Optimizing Network Access Selection in Wireless Heterogeneous Networks using Velocity, Location, Policy and Qos Details

As the interest in 4G communication systems continues to grow, both academia and industry agree that a symbiotic relationship between various wireless systems is required to provide continuous broadband coverage to mobile users. It is generally accepted that a single wireless access technology alone will be incapable of meeting the various requirements of mobility, data rate and coverage in the future. Future wireless systems are envisioned as being heterogeneous in that they will include a combination of various wireless access technologies such as 3G, WLAN, and WiMAX and will have a common IP core. To fully utilize the various resources and maintain seamless connectivity in the future heterogeneous wireless environment, intelligent handoff schemes that are flexible, scalable and proactive are essential. Therefore, a new handoff decision method, one that works in a novel business model--Heterogeneous Wireless Service Provider (HWSP)--was developed with an aim to improve the mobile user's user experience. More effort was spent to achieve a good level of user satisfaction, by making the entire selection process automatic, and the user oblivious of the underlying network selection intricacies. The algorithm is able to make the final network decision, based on any particular user's speed, location, QoS demands and preference policies. This allows the algorithm to prevent unwanted handoffs and reduce the cost associated with connecting to suboptimal networks

Context-aware multi-attribute decision multi - attribute decision making for radio access technology selection in ultra dense network

Ultra Dense Network (UDN) is the extreme densification of heterogeneous Radio Access Technology (RAT) that is deployed closely in coordinated or uncoordinated manner. The densification of RAT forms an overlapping zone of signal coverage leading to the frequent service handovers among the RAT, thus degrading overall system performance. The current RAT selection approach is biased towards network-centric criteria pertaining to signal strength. However, the paradigm shift from network-centric to user-centric approach necessitates a multi-criteria selection process, with methodology relating to both network and user preferences in the context of future generation networks. Hence, an effective selection approach is required to avoid unnecessary handovers in RAT. The main aim of this study is to propose the Context-aware Multiattribute decision making for RAT (CMRAT) selection for investigating the need to choose a new RAT and further determine the best amongst the available methods. The CMRAT consists of two mechanisms, namely the Context-aware Analytical Hierarchy Process (CAHP) and Context-aware Technique for Order Preference by Similarity to an Ideal Solution (CTOPSIS). The CAHP mechanism measures the need to switch from the current RAT, while CTOPSIS aids in decision making to choose the best target RAT. A series of experimental studies were conducted to validate the effectiveness of CMRAT for achieving improved system performance. The investigation utilises shopping mall and urban dense network scenarios to evaluate the performance of RAT selection through simulation. The findings demonstrated that the CMRAT approach reduces delay and the number of handovers leading to an improvement of throughput and packet delivery ratio when compared to that of the commonly used A2A4-RSRQ approach. The CMRAT approach is effective in the RAT selection within UDN environment, thus supporting heterogeneous RAT deployment in future 5G networks. With context-aware selection, the user-centric feature is also emphasized

Mecanismos de mobilidade rápida com suporte de QdS

Mestrado em Engenharia Electrónica e TelecomunicaçõesA área das redes de comunicações está, neste momento, a deparar-se com um novo paradigma causado pela tendência de convergência de redes sem fios e celulares. Desta convergência resultará a existência de uma camada de rede integradora, para facilitar o suporte de mecanismos de Qualidade de Serviço e mobilidade. Aqui, o suporte de mobilidade rápida e transparente, sem ser perceptível pelo utilizador, tem sido alvo de muita atenção, apesar de ainda existirem algumas limitações no seu suporte. A mobilidade transparente entre redes celulares, sem fios e fixas, é ambicionada mas ainda não foi alcançada. O trabalho realizado nesta Dissertação consiste na descrição, especificação, implementação e teste de uma nova arquitectura de mobilidade sobre o protocolo IP. Esta arquitectura é baseada no protocolo de mobilidade Mobility Support for IPv6 e em extensões de Fast Handovers for Mobile IPv6, sendo capaz de efectuar handovers iniciados pelo terminal e pela rede. A mobilidade é transparente entre tecnologias de acesso heterogéneas, através da integração de mecanismos de qualidade de serviço, tais como autorização de handovers, controlo de acesso, reserva e atribuição de recursos no novo ponto de ligação e também integrada com subsistemas de autenticação. São também propostos outros mecanismos de mobilidade rápida que fazem uso do protocolo multicast para distribuir os fluxos de tráfego direccionados ao terminal, pelos routers de acesso vizinhos, permitindo que os terminais móveis mudem para qualquer router de acesso na vizinhança sem interrupção dos serviços em curso. Estes mecanismos foram projectados para terminais móveis com grandes requisitos de mobilidade. No âmbito do projecto IST Daidalos foi efectuada a integração de uma rede de próxima geração (4G) de forma a permitir a realização de testes de desempenho e conformidade aos mecanismos propostos. A presente Dissertação efectua uma avaliação de desempenho de uma arquitectura de mobilidade, em cenários intra- e inter-tecnologia, numa rede de testes real. Nesta avaliação foram utilizadas as métricas de atraso, jitter e perdas de pacotes nas fases de preparação e execução do handover. O impacto deste processo em comunicações de dados sobre TCP e UDP é também analisado. A arquitectura e os resultados obtidos no demonstrador real são apresentados e discutidos. ABSTRACT: The field of network communications is, nowadays, facing a new paradigm caused by the forthcoming convergence of cellular and wireless data networks, which seems unavoidable. This convergence will result on an integration layer, to ease the support for Quality of Service and mobility mechanisms. Here, the support for fast and seamless mobility, not perceptible by the user, has been getting much attention, although several limitations still exist in this support. Seamless mobility between cellular, wireless and wired data networks is envisioned, but not yet achieved. The work performed in the scope of this thesis aims to describe, specify, implement and test a novel mobility architecture based on the IP protocol. This architecture is based on the mobility protocol Mobility Support for IPv6 and on extensions of Fast Handovers for Mobile IPv6 RFCs, and is able to provide mobile terminal and network initiated handovers. The mobility is seamless across heterogeneous access technologies, by integrating Quality of Service mechanisms, such as handover authorization, access control, resources reservation and allocation at the new point of attachment, also integrated with an authentication sub-system. Other novel fast mobility mechanisms are also proposed, which make use of the multicast protocol to distribute the traffic flows directed to the terminal during the handover process among the neighbour access routers, allowing the terminal to handover to any access router in the vicinity without disruption of the ongoing services. These latter mechanisms were designed to mobile terminals with high mobility requirements. In the scope of the IST Daidalos framework an integration process of a next generation (4G) network was carried out in order to perform performance and compliance tests to the proposed mechanisms. Furthermore, this thesis also evaluates the performance of a mobility architecture, both in intra and intertechnology scenarios, in a real testbed. In this evaluation were considered metrics such as packet delay, jitter and loss of the handover in its preparation and execution phases. The impact of the handover on ongoing TCP and UDP data communications is also addressed. The architecture and results obtained from the real demonstrator are also presented and discussed

Access Network Selection in Heterogeneous Networks

The future Heterogeneous Wireless Network (HWN) is composed of multiple Radio Access Technologies (RATs), therefore new Radio Resource Management (RRM) schemes and mechanisms are necessary to benefit from the individual characteristics of each RAT and to exploit the gain resulting from jointly considering the whole set of the available radio resources in each RAT. These new RRM schemes have to support mobile users who can access more than one RAT alternatively or simultaneously using a multi-mode terminal. An important RRM consideration for overall HWN stability, resource utilization, user satisfaction, and Quality of Service (QoS) provisioning is the selection of the most optimal and promising Access Network (AN) for a new service request. The RRM mechanism that is responsible for selecting the most optimal and promising AN for a new service request in the HWN is called the initial Access Network Selection (ANS). This thesis explores the issue of ANS in the HWN. Several ANS solutions that attempt to increase the user satisfaction, the operator benefits, and the QoS are designed, implemented, and evaluated. The thesis first presents a comprehensive foundation for the initial ANS in the H\VN. Then, the thesis analyses and develops a generic framework for solving the ANS problem and any other similar optimized selection problem. The advantages and strengths of the developed framework are discussed. Combined Fuzzy Logic (FL), Multiple Criteria Decision Making (MCDM) and Genetic Algorithms (GA) are used to give the developed framework the required scalability, flexibility, and simplicity. The developed framework is used to present and design several novel ANS algorithms that consider the user, the operator, and the QoS view points. Different numbers of RATs, MCDM tools, and FL inference system types are used in each algorithm. A suitable simulation models over the HWN with a new set of performance evolution metrics for the ANS solution are designed and implemented. The simulation results show that the new algorithms have better and more robust performance over the random, the service type, and the terminal speed based selection algorithms that are used as reference algorithms. Our novel algorithms outperform the reference algorithms in- terms of the percentage of the satisfied users who are assigned to the network of their preferences and the percentage of the users who are assigned to networks with stronger signal strength. The new algorithms maximize the operator benefits by saving the high cost network resources and utilizing the usage of the low cost network resources. Usually better results are achieved by assigning the weights using the GA optional component in the implemented algorithms

Network access selection in heterogeneous wireless networks

In heterogeneous wireless networks (HWNs), both single-homed and multi-homed terminals are supported to provide connectivity to users. A multiservice single-homed multi-mode terminal can support multiple types of services, such as voice call, file download and video streaming simultaneously on any one of the available radio access technologies (RATs) such as Wireless Local Area Network (WLAN), and Long Term Evolution (LTE). Consequently, a single-homed multi-mode terminal having multiple on-going calls may need to perform a vertical handover from one RAT to another. One of the major issues in HWNs is how to select the most suitable RAT for multiple handoff calls, and the selection of a suitable RAT for multiple-calls from a single-homed multi-mode terminal in HWNs is a group decision problem. This is because a single-homed multi-mode terminal can connect to only one RAT at a time, and therefore multiple handoff calls from the terminal have to be handed over to the same RAT. In making group decision for multiple-calls, the quality of service (QoS) requirements for individual calls needs to be considered. Thus, the RAT that most satisfies the QoS requirements of individual calls is selected as the most suitable RAT for the multiple-calls. Whereas most research efforts in HWNs have concentrated on developing vertical handoff decision schemes for a single call from a multi-mode terminal, not much has been reported in the literature on RAT-selection for multiple-calls from a single-homed multi-mode terminal in next generation wireless networks (NGWNs). In addition, not much has been done to investigate the sensitivity of RAT-selection criteria for multiple-calls in NGWNs. Therefore, this dissertation addresses these issues by focusing on following two main aspects: (1) comparative analysis of four candidate multi-criteria group decision-making (MCGDM) schemes that could be adapted for making RAT-selection decisions for multiple-calls, and (2) development of a new RAT-selection scheme named the consensus RAT-selection model. In comparative analysis of the candidate RAT-selection schemes, four MCGDM schemes namely: distance to the ideal alternative-group decision making (DIA-GDM), multiplicative exponent weighting-group decision making (MEW-GDM), simply additive weighting-group decision making (SAW-GDM), technique for order preference by similarity to Ideal solution-group decision making (TOPSIS-GDM) are considered. The performance of the multiple-calls RAT-selection schemes is evaluated using the MATLAB simulation tool. The results show that DIA-GDM and TOPSIS-GDM schemes are more suitable for multiple handoff calls than SAW-GDM and MEW-GDM schemes. This is because they are consistent and less-sensitive in making RAT-selection decision than the other two schemes, with regards to RAT-selection criteria (service price, data rate, security, battery power consumption and network delay) in HWNs. In addition, the newly developed RAT-selection scheme incorporates RAT-consensus level for improving RAT-selection decisions for multiple-calls. Numerical results conducted in MATLAB validate the effectiveness and performance of the newly proposed RAT-selection scheme for multiple-calls in HWNs

Telecommunications Wireless Generations: Overview, Technological Differences, Evolutional Triggers, and the Future

This study expands on prior studies on wireless telecommunication generations by examining the technological differences and evolutional triggers that characterise each Generation (from 1G to 5G). Based on a systematic literature review approach, this study examines fifty (50) articles to enhance our understanding of wireless generation evolution. Specifically, this study analyses i) the triggers that necessitated the evolution of wireless telecommunication generations and ii) makes a case regarding why it is imperative to look beyond the fifth Generation (5G) network technologies. The authors propose areas for future research