Learning Based Proactive Handovers in Heterogeneous Networks

Vertical handover management plays an essential role in wireless network technologies, mainly due to the rapid development of various radio access technologies (RATs) that require users to connect seamlessly from one RAT to another. However, in multiple RAT environments, vertical handover management encounters different challenges, including unnecessary handovers, handover failures, ping-pong handovers, and unsuitable access network selection. Essential in vertical handover management is maintaining the desired quality of service (QoS) by the mobile device user. The seamless movement of mobile device users as they run various applications depends on a well-performing vertical handover decision-making algorithm. This bears special significance in a heterogeneous network environment. This paper proposes a vertical handover algorithm that considers user preferences (i.e., a vertical handover algorithm that evaluates the application currently running on a user device). The main objective of the algorithm is to determine when it is necessary to perform the handover, depending on the applications running on the mobile device. The proposed algorithm utilizes a fuzzy logic system to assess whether the handover is necessary and a multiattribute decision-making (MADM) method to select the best available radio access network. A simulation scenario involving different applications at various mobile device velocities was developed. The results proved the algorithm’s effectiveness compared to some of the earlier proposed vertical handover algorithms. At velocities below 10 m/s and 30 m/s, the proposed algorithm had 0% and 15.02% unnecessary handovers, respectively, while the technique for order preference by similarity to ideal solution (TOPSIS) utility’s function-based algorithm obtained 12.38% and 23.24% at the same velocities, respectively. In addition, compared to TOPSIS, the obtained results of the proposed algorithm demonstrated a lower handover failure rate and ping-pong rate for a velocity span of 1–30 m/s for the considered user applications.

Mobile Internet Protocol Television (IPTV) provides users with multimedia content through wireless access technologies whenever they want and wherever they are. However, vertical handover in heterogeneous networks results in long interruption time and large packet loss rate, which poses a challenge for seamless mobile IPTV service. The existing solutions that make use of the heterogeneous access networks to transmit multimedia content have two drawbacks: high bandwidth consumption of the wireless networks and lots of packets loss when a user resides in the overlapped area of the boundary. To solve these issues, we propose a new soft handover mechanism, based on the IPTV server and the consumer electronic devices. The proposed Parallel Soft Handover (PSH) divides the Real-time Transport Protocol (RTP) packets according to the packet loss rates, and exploits different networks efficiently by using parallel transmission. Moreover, the selective retransmission for RTP packets is introduced to reduce the packet loss. Simulation results demonstrate that the PSH can reduce the packet loss rate, as well as obtain a more efficient use of the wireless bandwidth.

Choosing or switching between heterogeneous networks according to the highest performance in terms of quality of service is largely inefficient in vertical handover. In fact a service may have unstable performance and require highly frequent vertical handover procedures. In this paper we consider the impact of statistical fluctuations of performance parameters (decision under risk) and propose a soft algorithm that exploits the statistical knowledge in order to reduce outage probability.

The evolution of cellular networks from one generation to another has led to the deployment of multiple radio access technologies (such as 2G/2.5G/3G/4G) in the same geographical area. This scenario is termed heterogeneous cellular networks. In heterogeneous cellular networks, radio resources can be jointly or independently managed. When radio resources are jointly managed, joint call admission control algorithms are needed for making radio access technology selection decisions. This chapter gives an overview of joint call admission control in heterogeneous cellular networks. It then presents a model of load-based joint call admission control algorithm. Four different scenarios of call admission control in heterogeneous cellular networks are analyzed and compared. Simulations results are given to show the effectiveness of call admission control in the different scenarios. The coexistence of different cellular networks in the same geographical area necessitates joint radio resource management (JRRM) for enhanced QoS provisioning and efficient radio resource utilization. The concept of JRRM arises in order to efficiently manage the common pool of radio resources that are available in each of the existing radio access technologies (RATs) (Perez-Romero et al, 2005). In heterogeneous cellular networks, the radio resource pool consists of resources that are available in a set of cells, typically under the control of a radio network controller or a base station controller. There are a number of motivations for heterogeneous wireless networks. These motivations are (1) limitation of a single radio access technology (RAT), (2) users’ demand for advanced services and complementary features of different RATs, and (3) evolution of wireless technology. Every RAT is limited in one or more of the following: data rate, coverage, security-level, type of services, and quality of service it can provide, etc. (Vidales et al, 2005). A motivation for heterogeneous cellular networks arises from the fact that no single RAT can provide ubiquitous coverage and continuous high QoS levels across multiple smart spaces, e.g. home, office, public smart spaces, etc. Moreover, increasing users’ demand for advanced services that consume a lot of network resources has made network researchers developed more and more spectrally efficient multiple access and modulation schemes to support these services. Consequently, wireless networks have evolved from one generation to another. However, due to huge investment in existing RATs, operators do not readily discard their existing RATs when they acquire new ones. This situation has led to coexistence of multiple RATs in the same geographical area.

The integration of heterogeneous wireless networks allows the mobile users to benefit simultaneously from the radio coverage of different access technologies (RAT: Radio Access Technology) and the diversity of applications. Nowadays, applications are becoming more and more critical in terms of Quality of Service (QoS) and dynamicity. Handover mechanism is responsible of guaranteeing the required quality of service in ubiquitous environment when mobile users roam across different RATs. The diversification of context metrics offered by these different networks has a direct impact on the user perceived quality of service especially during the network selection process. The present work addresses the network selection process, which is the most important stage of the vertical handover decision mechanism. Our proposed algorithm for Vertical Handover decision making is based on the context awareness and the quality of experience (QoE). It integrates the threshold values of sensitive criteria, which are considered as the required metrics in the making decision process used to select the optimal target network. However, we define a decision function that checks the performance of the given networks and identifies the best solution. Performance offered by the chosen network has to be reviewed since the handover is launched to control the quality of service perceived by the end user. Simulation results improve the perceived network performance by avoiding unnecessary handover. In Ubiquitous environment, most Handover decision mechanisms generate a ping pong effect caused by the inefficiency of the network handover metrics which do not consider the required end user performance. As compared to several existing algorithms, our algorithm fits the expected changes in the network performance and the users preferences without wastage of network resources. It reduces the processing delay and the complexity level caused by unnecessary computation over available radio access technologies which do not ensure required connection performance.

The pouring of more and more attractive radio access technologies (RATs) with complementary characteristics has inspired the trends of interworking and convergence in future wireless systems. End-to-end reconfigurability (E2R) is an approach toward the convergence of diverse RATs. This paper aims at investigating an effective seamless vertical handover (VHO) scheme for E2R systems. The system model supporting the VHO scheme is brought forward. A network sort algorithm is developed enabling terminals to select the most appropriate network to handover. Particularly, we propose a novel handover trigger algorithm based on quality of service (QoS) evaluation allowing terminals to initiate a handover when the QoS is lower than their expected value. Simulation results reveal that the proposed VHO scheme enhances the user satisfaction as well as optimizes the overall network performance.

One of the major design issues in heterogeneous wireless networks is the support of seamless vertical handover for mobile users. The cognitive capability for mobile terminal enables the functionalities of system parameter estimation and learning. By utilizing these parameters, cognitive users make a

Guaranteeing the quality of service (QoS) for real time applications is one of the challenging issues in next generation all-IP networks. Analysing the user perceived throughput is essential to measure the QoS experienced by real time applications. Medium access control (MAC) mechanism of the serving access network as well as the vertical handover (VHO) algorithm used by the mobile terminals (MTs) for target network selection have significant impact on user perceived throughput. Apart from that the upper layer mobility management protocol also influences the throughput performance considerably. The existing frameworks for throughput analysis do not adequately address the MAC specific issues. In this work, we have developed an analytical framework to analyse user perceived throughput considering the effect of both MAC specific details and upper layer mobility management protocol. Using our proposed framework, we have compared the throughput performance of video traffic application when mobile IPv6 (MIPv6) and seamless IP diversity based generalized mobility architecture (SIGMA) are used for mobility management. Our analysis reveals that the superiority of SIGMA over MIPv6 is actually conditional on the performance of the underlying VHO algorithm. Extensive simulations have been done to validate the analytical results.

The Internet Engineering Task Force provides a network-based mobility management solution to execute handover in heterogeneous networks on network-side called Proxy Mobile IPv6 (PMIPv6). In this data article, data are presented during the horizontal and vertical handover on video communication in PMIPv6 mobility protocols. The handover data are gathered using several measurement factors, which are latency, jitter, cumulative measured, and peak signal noise ratio under network simulation software, for both horizontal and vertical handovers [8].

A novel SIP based procedure for congestion aware handover in heterogeneous networks

In this paper, we suggest about MIH (Media Independent Handover) supporting fully distributed handover in heterogeneous network based on Open vSwitch and OpenFlow. Although, personal mobile devices which are released recently have more than 2 mobile network interfaces, there is a small chance to utilize them simultaneously. To do this, MIH is suggested to guarantee the quality of application service when terminals of service users move to the other feature of wireless network in heterogeneous wireless network environment. Also, Open vSwitch of software type of various factors in SDN (Software Defined Network) and OpenFlow which has a control function by interacting with Data Path on network switch have arisen as a proposal to utilize wireless interfaces.Thus, in this paper, we experimented changes in packet flow of wireless interfaces. Moreover, we suggest a method of MIH based on SDN to guarantee communication quality of devices which uses more than 2 wireless interfaces.

Heterogeneous wireless access networks (HWAN) will create a market for the delivery of an extensive collection of novel and attractive services and contents. Accounting and pricing the ubiquitous services will play a key role from both service providers and users point of view. By one hand, wireless service providers (WSP) look for the maximum revenue and utilization rate and by other hand users will select service providers depending on the offered price and the Quality of Service (QoS) assurance. In such a market-based scenario, accounting will become an effective tool that satisfies the users' service demands and maximizes the revenue of the providers. For WSP is of vital importance to define a charging and accounting architecture that supports fast and easy the provision of existent and new services with the best quality. In this sense, a dynamical network selection mechanism has to be developed to decide an appropriate radio access cell or technology for a specific service. Additionally, service providers must consider alternative solutions to situations where the best quality for the requested service cannot be provided, allowing them maintaining a high user satisfaction level. In this paper we propose a simple QoS-based dynamic pricing approach for services provisioning into a heterogeneous wireless access networks environment which attempts to increase user's satisfaction level by firstly, maximizing the provided QoS level, and secondly, by applying dynamic pricing strategies according to the QoS. These strategies will allow service providers to maximize their profits. Simulations results demonstrate that the proposed dynamic pricing approach benefits both users and WSP. Results suggest that users have better overall satisfaction due to a better QoS level and fairer prices. The analysis shows that our proposed pricing approach helps increasing WSPs profits compared to the application of the flat-rate pricing model into a competitive market-model.

We propose and evaluate a vertical handover mechanism for TCP, based on receiver bandwidth delay product (BDP) measurement and congestion control using the receiver's advertised window. It addresses the negative impact of abrupt changes in link capacity and latency on TCP performance during make-before-break vertical handover in heterogeneous networks, enabling TCP to seamlessly adapt to new conditions. It resolves the problem of buffer overflow in a low capacity network on handover from a high capacity network, and the under-utilisation problem on handover in the reverse direction. All modifications are restricted to the mobile device, and the proposed technique is fully interoperable with existing TCP and mobile IP infrastructure. It maintains end-to-end semantics, supports IP security, and can be easily deployed

In this paper we propose a software module for continuously monitoring a wireless network card, able to handle and rise IEEE 802.21 compatible primitives in support for vertical handover in heterogeneous networks. This module is intended to be installed on a multimod mobile terminal, and will automatically monitor and switch the connection link, when performing vertical handover. Besides the software architecture, we describe the real-time behavior of the module by using state machine diagrams.

Vertical handover supporting pervasive computing in future wireless networks