Handover Operation Research Articles

Handover Management in Software-Defined Ultra-Dense 5G Networks

Ultra-densification is a key approach aimed at satisfying high data traffic in next-generation 5G networks. However, the high number of small cell eNB deployments in such ultra-dense networks (UDNs) may result in unnecessary, frequent, and back-and-forth handovers, with additional problems related to increased delay and total failure of the handoff process. Additionally, due to the separation of control and data signaling in 5G technology, the handover operation must be executed in both tiers. In this article, we propose an SDN-based mobility and available resource estimation strategy to solve the handover delay problem. Here, we estimate the neighbor eNB transition probabilities of the mobile node and their available resource probabilities by using a Markov chain formulation. This allows a mathematically elegant framework to select the optimal eNBs and then assign these to mobile nodes virtually, with all connections completed through the use of OpenFlow tables. Finally, we compare the conventional LTE and our proposed handover strategies by analyzing the observed delays according to the densification ratio parameter. Also, we analyze the handover failure ratios of both strategies according to the user number. Results reveal that the proposed strategy reduces the handover delay and failures by 52 and 21 percent compared to the conventional approach.

Distributed Group-Based Mobility Management Scheme in Wireless Body Area Networks

For group-based mobility management in 6LoWPAN-based wireless body area networks (WBAN), some schemes using the Proxy Mobile IPv6 (PMIP) have been proposed. However, the existing PMIP-based mobility schemes tend to induce large registration delay and handover delay. To overcome such limitations, we propose a new distributed group-based mobility management scheme, in which the Local Mobility Anchor (LMA) function is implemented by each Mobile Access Gateway (MAG) and the handover operation is performed between two neighboring MAGs without the help of LMA. Besides, each MAG maintains the information of the group of mobile sensors and aggregates the Authentication-Authorization-Accounting (AAA) query messages for a group of mobile sensors as a “single” message to decrease the control overhead. By numerical analysis, it is shown that the proposed scheme can reduce the registration and handover delays, compared to the existing PMIP-based mobility schemes.

RETRACTED ARTICLE: Improved fast handover method for multiple node by using mobile nodes guide

The fast mobile internet protocol version 6 (FMIPv6) was suggested as a fast handover mechanism over the mobile wireless Internets in order to reduce the handover latency of a mobile node (MN). However, FMIPv6 was originally designed to deal with single MN's. In mobile wireless Internet, a multiple MNs may do a handover at the same time as a consequence of its movement from one network to another new one. This will therefore lead to the bandwidth waste and low handover performance. This paper intends to propose a multiple handover-based mobile node (MHB-MN) control method and an enhanced FMIPv6 mechanism in order to resolve the abovementioned problem. The proposal of such an MHB-MN method aims at having one mobile node work as a guide for a group of neighboring MNs. This means that the guide of MN prepares itself for a handover before actually taking the initial steps of the actual handover operation. Based on obtained results, it is plainly observable that by MHB-MN method, the handover initiation time, handover latency and handover control messages can be reduced compared to those of FMIPv6. Furthermore, the contention of the wireless channel for multiple MNs can be improved by the use of fewer control messages. Finally, the paper introduces an analytical model to show that by enabling the MHB-MN method and enhancing the FMIPv6 method, a multiple of nodes can perform rapid handover processes with low handover latency compared to that of the FMIPv6 technique.

Mobility Management for 6LoWPAN Wireless Sensor Networks in Critical Environments

This paper proposes a mobility management protocol for 6LoWPAN wireless sensor networks. In this protocol, the 6LoWPAN architecture is proposed, and both the hierarchical IPv6 address structure and the address configuration algorithm for 6LoWPAN WSN are presented. Based on the proposed architecture, the intra-network and inter-network mobility handover algorithms are proposed. In the algorithms, a mobile sensor node does not need a care-of address during the mobility process, so the mobility handover process does not include the care-of address configuration operation and the address binding operation. As a result, the mobility handover cost and delay are reduced. In addition, a mobile node does not need to be involved in the mobility handover process, so the energy is saved and the life span is prolonged. During the intra-network mobility handover process, a link address is used to identify a mobile node, so the size of the messages used to achieve the mobility handover operation is reduced substantially. As a result, the transmission cost and delay are reduced. The paper analyzes and compares the performance parameters of MIPv6, Inter-MARIO and the proposed protocol, including the mobility handover cost, the mobility handover delay and the packet loss rate. The data results show that the proposed protocol reduces the mobility handover cost, shortens the mobility handover delay and decreases the packet loss rate.

Design VMAP with caching scheme to improving handover performance on the HMIPV6 network

The integration of WiMAX and Mobile IPV6 (MIPV6) protocol is one of the hottest wireless network technology trends. HMIPV6 uses a Mobility Anchor Point (MAP) as the Local HA, to regionalize the handover operation, reduce lots of the Binding Update (BU) information transmission of MIPV6 among HA, CN and MN, and to achieve the goal of fast handover. However, the BU procedure of HMIPV6 consumes too much time and causes packet loss and transmission delay. Therefore, this paper proposes VMAP-C (VMAP with Caching) to improve the effectiveness and efficiency of handover. In this scheme, we use the original VMAP method to improve the performance of signal transmissions and also utilize caching scheme to replace the existing DAD mechanism. Then, we perform simulations with the NS-2 simulator tool, each VMAP is ranged from 4 to 8 ARs, and also the number of MN increases from 1 to 100. The final simulation results indicate that the proposed VMAP-C obtains a reduction of about 15.62–52.28% in Handover delay, decreases Jitter of arriving inter-packets by about 10.63–50.61%, enhances the Throughput of the system by about 6.56–12.63%, and reduces the Packet loss ratio by about 9.57–87.69% compared to VMAP. Consequently, we prove that the VMAP-C scheme can obtain lower delay, Jitter and Packet loss ratio more than VMAP, and achieve higher system Throughput and better handover performance on the HMIPV6 network.

A Network Selection Algorithm Based on Enhanced Access Router Discovery in Heterogeneous Wireless Networks

The management process between different wireless technologies for mobile devices is very important to complete the handover operations. The handover operation needs to determine the delay and packet loss in order to be the quality of service within a certain level. Selecting the best available network at the appropriate time is very significant in the direction of realizing ubiquitous networks. In this paper a network selection approach named enhanced access router discovery (EARD) is proposed. The approach is developed to work in a heterogeneous environment including of WiMAX and WLAN networks. The EARD method utilizes the prioritized rating for multiple criteria (PRMC) proposed for selecting the target network. The proposed approach is evaluated with respect to various conditions with different traffic types. The simulation results show that our proposed approach outperform the traditional network selection methods is selecting the most appropriate network.

Fast authentication mechanism with provable correctness for cluster‐based VANETs

ABSTRACTVehicle ad hoc networks are self‐configurable networks with dynamic topologies. All involved nodes in vehicle ad hoc networks, including vehicles and roadside devices, have to share the responsibility for achieving handover operation and providing communication services. Such networks are more vulnerable to the malicious attacks than traditional wireless networks because of the shortage of the fixed infrastructure. Moreover, because the vehicles always move from one area to another very quick, how to handle the handover between roadside devices has become a crucial challenge in designing the system. For providing secure and seamless communications in such networks, we develop a robust and fast handover mechanism. We have conducted essential experiments to demonstrate the superiority of the new mechanism to other works. In particular, we have applied the BAN logic model to prove the correctness of mutual authentication between involved participants. Copyright © 2013 John Wiley & Sons, Ltd.

An enhanced fast IP mobility management using multiple care-of-addresses in vehicular networks

The IETF has developed the FMIPv6 which can be used for fast IP mobility management in vehicular networks. In the FMIPv6 protocol, if a prediction about a mobile node movement is incorrect, large handover delay may occur during handover operation. In this paper, we propose an enhanced fast IP mobility management, called EMIPv6, which can reduce both the handover latency and the packet loss in vehicular networks by utilising multiple Care–of–Addresses (CoAs) and the IEEE 802.21 Media Independent Handover (MIH) information service. The salient feature of the EMIPv6 is that multiple CoAs are, by extending the IETF FMIPv6 and the MIH information service, prepared in advance to reduce the movement prediction error of FMIPv6, thereby drastically reducing both handover latency and packet loss. Both mathematical analysis and simulation have been done for performance evaluation. The simulation results show that the EMIPv6 outperforms FMIPv6 in both handover latency and packet loss.

Optimizing throughput performance of FMIPv6 over legacy 802.11 networks using iterative scanning

Predictive handover protocols like FMIPv6 have been proposed to provide seamless handover to MNs with minimum handover latency and packet losses. An essential prerequisite of FMIPv6 protocol is the advance discovery of candidate access points while the MN is still connected to its Present Access Router, a process which is carried out by the underlying data link layer protocol. The FMIPv6 standard only specifies the seamless handover operation at the network layer and does not take into consideration the impact of the relevant mechanism, such as the advance access point discovery process, on the overall seamless operation in terms of packet losses. At the data-link layer, the MN may repeatedly preform channel scanning operations to discover the in-range candidate APs. During the scan process, a MN is unable to transmit or receive packets leading to service quality degradation.This paper will analyze the implication of the IEEE 802.11 scanning process, that is carried out in advance to the actual initiation of the FMIPv6 handover process as part of the candidate access points discovery process. The impact of such a scan process is assessed on the overall seamlessness of the FMIPv6 protocol and its impact on the user’s QoE. In this regard, an iterative channel scanning solution approach would be described, which has been proposed to offset the adverse affects of 802.11 channel scanning process on the overall seamlessness of the FMIPv6 protocol in a legacy 802.11 network, especially during the candidate AP discovery process. A detailed evaluation of the performance of our proposed scheme will be presented based on extensive simulation analysis.

QoS-guaranteed IP mobility management for fast-moving vehicles with multiple network interfaces

In this study, the authors present a quality-of-service (QoS)-guaranteed IP mobility management scheme for fast-moving vehicles with multiple wireless network interfaces. The idea of the proposed mechanism consists of two things. One is that new wireless connections are established to available wireless channels whenever the measured data rate at the mobile node drops below to the required data rate of the user requirement. The other is that parallel distribution packet tunnels between an access router and the mobile node are dynamically constructed using multiple wireless network interfaces in order to guarantee the required data rate during the mobile node's movement. By doing these methods, the required data rate of the mobile node can be preserved while eliminating the possible delay and packet loss during handover operation, thus resulting in the guaranteed QoS. The architecture of the Internet engineering task force standard hierarachical mobile IPv6 (HMIPv6) has been extended to realise the proposed scheme, and detailed algorithms for the extension of HMIPv6 has been designed. Finally, simulation has been done for performance evaluation, and the simulation results show that the proposed mechanism demonstrates guaranteed QoS during the handover with regard to the handover delay, packet loss and throughput.

Multi-objective handover in LTE macro/femto-cell networks

One of the key elements in the emerging, packet-based long term evolution (LTE) cellular systems is the deployment of multiple femtocells for the improvement of coverage and data rate. However, arbitrary overlaps in the coverage of these femto-cells make the handover operation more complex and challenging. As the existing handover strategy of LTE systems considers only carrier to interference plus noise ratio (CINR), it often suffers from resource constraints in the target femtocell, thereby leading to handover failure. In this paper, we propose a new efficient, multi-objective handover solution for LTE cellular systems. The proposed solution considers multiple parameters like signal strength and available bandwidth in the selection of the optimal target cell. This results in a significant increase in the handover success rate, thereby reducing the blocking of handover and new sessions. The overall handover process is modeled and analyzed by a three-dimensional Markov chain. The analytical results for the major performance metrics closely resemble the simulation results. The simulation results show that the proposed multi-objective handover offers considerable improvement in the session blocking rates, session queuing delay, handover latency, and goodput during handover.

Realization of Seamless Mobility in Heterogeneous Wireless Networks based on IEEE 802. 21 Framework

Wireless and mobile networks are evolving very rapidly. The mobile nodes in the wireless networks are having multiple interfaces with different radio access technologies (RATs) which are having different capabilities, cost and performance ratio. The use of non-PC based portable devices is increasing due to their flexible usage. The wireless and mobile network which is formed by these non-PC and PC based devices is heterogeneous in nature and these networks are co-located. Multiple interfaces can be included in the mobile device by using separate hardware and software modules. A mobile user wants to be Always Best Connected (ABC) as per its various requirements and availability in a particular environment. When a mobile node leaves the current network and joins the other network, a handover operation is needed and performed. The Handover operation is used to achieve seamless mobility and is of two types, first is in between same RATs and second is in between different RATs. For seamless and smooth handover operations across heterogeneous networks, IEEE has published a standard, named as IEEE 802.21. This paper presents a comprehensive description on the issues and challenges for achieving the seamless mobility in a heterogeneous environment. Apart from this, we also present the description of services provided by IEEE 802.21 standard and related vertical handover schemes to realize seamless mobility in heterogeneous network.

A Mobility Handover Scheme for IPv6-Based Vehicular Ad Hoc Networks

The paper proposes a mobility handover scheme MHVA for IPv6-based vehicular ad hoc networks. In MHVA, a vehicle is uniquely identified by its home IPv6 address, and it can keep the communication with other nodes without a care-of address during the mobility process. In addition, MHVA adopts an advanced mobility handover mechanism where the mobility handover operation in the network layer is completed before the one in the link layer is performed. As a result, during the advanced mobility handover process, a vehicle can keep the connection with its current associated AP in the link layer, so it can receive the data forwarded by the AP. Therefore, the packet loss rate is reduced, the mobility handover cost is decreased, and the mobility handover delay is shortened. From both the theoretical perspective and simulative perspective, the performance parameters of MHVA are evaluated, and the data results show that the mobility handover cost of MHVA is lower and the mobility handover delay is shorter.

VANET 상에서의 이동성을 고려한 안전한 메시지 인증기법

지능형 차량 네트워크(VANET)는 무선통신을 이용하여 차량 간 (V2V, Vehicle to Vehicle), 차량과 노변장치 간(V2I, Vehicle to Infrastructure)의 통신을 제공하는 네트워킹 기술이다. 현재 VANET통신은 자동차산업의 급속한 발전과 차량자동화로 인하여 산업계와 학계를 중심으로 연구가 활발히 진행되고 있다. VANET을 통해 유통되는 차량의 속도, 가속도, 도로 및 환경 모니터링정보는 운전자에게 안전운전과 관련된 서비스를 제공하는 분야로써 통신에서의 보안은 필수적인 요건이다. 지금까지 안전한 메시지 인증을 위한 많은 인증프로토콜들이 제시되어 왔다. 그 중에서도 Jung에 의해 제안된 VANET 알고리즘은 데이터베이스 검색 알고리즘인 블룸 필터를 RAISE 알고리즘에 적용하여 차량 밀집환경에서의 인증에 보다 효율적인 알고리즘을 제안하였다. 하지만 RAISE에서 사용한 k-anonymity는 정확한 차량의 ID정보를 얻기 위해 모든 메시지에 대해 전수조사 연산을 수행해야 하므로 차량의 수가 증가함에 따라 해시연산량이 지수적으로 증가한다. 또한 핸드오버가 발생하는 경우 완벽한 키전달 알고리즘을 제공하지 못한다. 본 논문에서는 RSSI기반 속도 및 거리 추정 알고리즘을 사용하여 사용자의 ID를 위치화하며 프로토콜의 핸드오버부분의 오류를 수정하여 안전하고 효율적인 알고리즘을 제공한다. Vehicular Ad Hoc Network(VANET) using wireless network is offering the communications between vehicle and vehicle(V2V) or vehicle and infrastructure(V2I). VANET is being actively researched from industry field and university because of the rapid developments of the industry and vehicular automation. Information, collected from VANET, of velocity, acceleration, condition of road and environments provides various services related with safe drive to the drivers, so security over network is the inevitable factor. For the secure message authentication, a number of authentication proposals have been proposed. Among of them, a scheme, proposed by Jung, applying database search algorithm, Bloom filter, to RAISE scheme, is efficient authentication algorithm in a dense space. However, k-anonymity used for obtaining the accurate vehicular identification in the paper has a weak point. Whenever requesting the righteous identification, all hash value of messages are calculated. For this reason, as the number of car increases, a amount of hash operation increases exponentially. Moreover the paper does not provide a complete key exchange algorithm while the hand-over operation. In this paper, we use a Received Signal Strength Indicator(RSSI) based velocity and distance estimation algorithm to localize the identification and provide the secure and efficient algorithm in which the problem of hand-over algorithm is corrected.

Design and implementation of ARIP for efficient handovers

AbstractMobile IPv6 (MIPv6), which is a protocol being standardized by Internet Engineering Task Force for global IP mobility support, is expected to have a key role for future All‐IP wireless networks. As the demands for delay sensitive multimedia applications increase, the handover latency and packet losses of MIPv6 become inadequate for these applications. Fast Handovers for Mobile IPv6 (FMIPv6) has been proposed to tackle the problem. However, FMIPv6 cannot work solely since it needs access router information for its fast handover operation. In this paper, we propose Access Router Information Protocol (ARIP), which performs a candidate access router discovery and a radio access network discovery in one protocol suite, to provide an efficient handover framework for MIPv6 and FMIPv6. ARIP is designed to cope with heterogeneous networks as well as homogeneous networks and to be closely coupled with FMIPv6 to provide the efficient handover performance. The performance evaluation of MIPv6, FMIPv6, and FMIPv6 with ARIP is performed in an actual network environment. The performance results show that FMIPv6 with ARIP can significantly improve the handover performance compared to the conventional handover approaches. Copyright © 2009 John Wiley & Sons, Ltd.

Energy‐efficient network selection with mobility pattern awareness in an integrated WiMAX and WiFi network

AbstractTo provide wireless Internet access, WiFi networks have been deployed in many regions such as buildings and campuses. However, WiFi networks are still insufficient to support ubiquitous wireless service due to their narrow coverage. One possibility to resolve this deficiency is to integrate WiFi networks with the wide‐range WiMAX networks. Under such an integrated WiMAX and WiFi network, how to conduct energy‐efficient handovers is a critical issue. In this paper, we propose a handover scheme with geographic mobility awareness (HGMA), which considers the historical handover patterns of mobile devices. HGMA can conserve the energy of handovering devices from three aspects. First, it prevents mobile devices from triggering unnecessary handovers according to their received signal strength and moving speeds. Second, it contains a handover candidate selection method for mobile devices to intelligently select a subset of WiFi access points or WiMAX relay stations to be scanned. Therefore, mobile devices can reduce their network scanning and thus save their energy. Third, HGMA prefers mobile devices staying in their original WiMAX or WiFi networks. This can prevent mobile devices from consuming too much energy on interface switching. In addition, HGMA prefers the low‐tier WiFi network over the WiMAX network and guarantees the bandwidth requirements of handovering devices. Simulation results show that HGMA can save about 59– 80% of energy consumption of a handover operation, make mobile devices to associate with WiFi networks with 16–62% more probabilities, and increase about 20–61% of QoS satisfaction ratio to handovering devices. Copyright © 2009 John Wiley & Sons, Ltd.

On the Use of Ad Hoc Cooperation for Seamless Vertical Handoff and Its Performance Evaluation

In heterogeneous network environments, it is very important for users to provide seamless services while satisfying quality-of-service, regardless of the connected access network. In this paper, we apply a concept of ad hoc cooperation for the vertical handoff in the heterogeneous network. For the seamless vertical handoff of mobile nodes, a neighbor ad hoc node assists some parts of the handoff procedures requiring large latency, such as authentication and IP registration procedures. Details of the vertical handover operation using the ad hoc cooperation are presented and its performance is evaluated. Numerical results show that the proposed vertical handoff procedure decreases the service disruption time and the probability of packet loss, compared with the conventional handoff methods that do not consider the cooperation of ad hoc node.

Improvements to seamless vertical handover between mobile WiMAX and 3GPP UTRAN through the evolved packet core

Recent mobile devices are integrated with multiple network interfaces. Users want their devices connected to the network anytime anywhere. It is highly feasible for a user to change connection to another network for users that leave the service area of its current serving network, where handover needs to be executed seamlessly such that ongoing service sessions are not interrupted. The handover operation not only requires switching the interfaces within a device but also involves seamless reconfiguration of the supporting networks. In this article, an improved IP-based vertical handover technology for mobile WiMAX , 3GPP legacy systems (i.e., Global System for Mobile communications and Universal Mobile Telecommunications System), and 3G Long Term Evolution is presented, which is based on existing optimized handover techniques between mobile WiMAX and 3GPP accesses. Formerly proposed 3GPP WiMAX optimized VHO solutions introduced new elements, such as the forward attachment function and access network discovery and selection function. The ANDSF supports the discovery of target access, and the FAF provides the functionality that authenticates the UE before the execution of VHO. However, the previous technique has limitations that result in data loss and abnormal disconnection to the source access. This article provides a solution by introducing an additional network element called the data forwarding function (DFF) that eliminates the data loss during VHO execution. In addition, the DFF resolves the problem of abrupt disconnection to the source network. The simulation results show that the proposed VHO technique is effective in minimizing data loss during VHO execution between mobile WiMAX and 3GPP networks. As the proposed solution of this article is an IP based handover solution, it can be similarly applied to other communication networks.

Improvement in University Satellite Operation Using Ground Station Network

The development of Ground Station Network (GSN) was proposed to achieve advanced operation for nano-satellites by the collaboration of university ground stations. GSN is a network of ground stations of universities and colleges and member stations are controlled remotely via the Internet. The service of the receiving station network was used in cubesat operation. GSN in receiving station service showed improvement of the amount of downlink data. The international network with collaboration of ground stations was carried out. The status data and picture data were acquired during the hand-over operation. As the result of international network operation, the collaborative operation with ground station abroad improves visible time and operation data received per one day. Doppler shift was measured using an amateur radio. The maximum difference of predicted frequency and measured frequency was detected for each pass. The correction method of TLE was tested using the frequency difference. The measurement result with corrected TLE from old TLE showed good agreement to the result with the new TLE.

A Unified Handover Management Scheme Based on Frame Retransmissions for TCP over WLANs

In ubiquitous networks based on Wireless Local Area Networks (WLANs) with limited individual coverage, mobile nodes will be likely to traverse different WLANs during TCP communication. An effective handover management scheme for achieving seamless and efficient communication throughout the handover operation is therefore crucial. To achieve this, the following three requirements are essential: (i) early initiation of handover, (ii) elimination of communication interruption upon handover, (iii) selection of an optimal WLAN. The handover scheme proposed in this study employs frame retransmission over WLAN as an indicator of link degradation, and a handover manager (HM) on the transport layer obtains the number of frame retransmissions on the MAC layer using a cross-layer architecture in order to achieve (i) and (iii). Then, it also employs multi-homing in order to achieve (ii). Simulations demonstrate that the proposed scheme can satisfy all of the three requirements and is capable of maintaining TCP performance throughout the handover operation.