Seamless integration of mobile WiMAX in 3GPP networks

As the wireless industry makes its way to the next generation of mobile systems, it is important to engineer solutions that enable seamless integration of emerging 4G access technologies within the currently deployed and/or evolved 2G/3G infrastructures. In this article we address a specific case of such a seamless integration, that of mobile WiMAX in evolved 3GPP networks. In this context we investigate the architecture and the key procedures that enable this integration, and we also introduce a novel handover mechanism that enables seamless mobility between mobile WiMAX and legacy 3GPP access, such as UTRAN or GERAN. The core characteristic of this novel handover mechanism is that mobile terminals do not need to support simultaneous transmission on both WiMAX and 3GPP accesses; therefore, it mitigates the RF coexistence issues that exist otherwise and improves handover performance. In addition, we provide a brief overview of mobile WiMAX and the evolved 3GPP network technologies, and we set the appropriate background material before presenting our proposed handover mechanism. Our main conclusion is that integrating mobile WiMAX in evolved 3GPP networks is a compelling approach for providing wireless broadband services, and mobility across WiMAX and 3GPP access can become seamless and efficient with no need for mobile terminals to support simultaneous transmission on both types of access.     

IP Flow Mobility in PMIPv6 Based Networks: Solution Design and Experimental Evaluation

The ability of offloading selected IP data traffic from 3G to WLAN access networks is considered a key feature in the upcoming 3GPP specifications, being the main goal to alleviate data congestion in cellular networks while delivering a positive user experience. Lately, the 3GPP has adopted solutions that enable mobility of IP-based wireless devices relocating mobility functions from the terminal to the network. To this end, the IETF has standardized Proxy Mobile IPv6 (PMIPv6), a protocol capable to hide often complex mobility procedures from the mobile devices. This paper, in line with the mentioned offload requirement, further extends PMIPv6 to support dynamic IP flow mobility management across access wireless networks according to operator policies. Considering energy consumption as a critical aspect for hand-held devices and smart-phones, we assess the feasibility of the proposed solution and provide an experimental analysis showing the cost (in terms of energy consumption) of simultaneous packet transmission/reception using multiple network interfaces. The end-to-end system design has been implemented and validated by means of an experimental network setup.     

A Secure Relay-Assisted Handover Protocol for Proxy Mobile IPv6 in 3GPP LTE Systems

The LTE (Long Term Evolution) technologies defined by 3GPP is the last step toward the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile telephone networks. Mobility management for supporting seamless handover is the key issue for the next generation wireless communication networks. The evolved packet core (EPC) standard adopts the proxy mobile IPv6 protocol (PMIPv6) to provide the mobility mechanisms. However, the PMIPv6 still suffers the high handoff delay and the large packet lost. Our protocol provides a new secure handover protocol to reduce handoff delay and packet lost with the assistance of relay nodes over LTE networks. In this paper, we consider the security issue when selecting relay nodes during the handoff procedure. During the relay node discovery, we extend the access network discovery and selection function (ANDSF) in 3GPP specifications to help mobile station or UE to obtain the information of relay nodes. With the aid of the relay nodes, the mobile station or UE performs the pre-handover procedure, including the security operation and the proxy binding update to significantly reduce the handover latency and packet loss. The simulation results illustrate that our proposed protocol actually achieves the performance improvements in the handoff delay time and the packet loss rate.     

Dynamic network composition for beyond 3G networks: a 3GPP viewpoint

The 3GPP network specification is currently undergoing major updates toward beyond 3G. The evolved 3GPP network will support interworking with multiple including non-3GPP - radio access networks, and support mobility between them. It will furthermore support personal area networks and moving networks. Generally, 3GPP is moving in the direction of an all-IP network. This article gives an overview of current beyond 3G trends in 3GPP, and particularly introduces a new 3GPP study item on network composition. The concept of network composition was developed by the EU project Ambient Networks. Whereas 3GPP until now assumes static networking relations, network composition addresses a dynamic, generic establishment of control-plane interworking between the heterogeneous network types of today, such as 3GPP core networks, non-3GPP operator networks, heterogeneous access networks, and personal area networks     

LTE与非3GPP接入网的系统架构研究

首先分析了LTE与非3GPP互通系统架构配置,描述了3GPP互通系统架构中的逻辑单元（包括用户设备、非3GPP可信网络、非3GPP不可信接入网和EPC）,给出了非3GPP互通系统架构中的接口与协议,讨论了非3GPP互通系统架构中的漫游问题。     

Extensions for Internet QoS paradigms to mobile IP: a survey

Mobile IP has been chosen as the core mobility management mechanism for wireless LANs, 3G cellular networks, and, most recently, aeronautical networks. It is viewed as a key element in providing a universal roaming solution across different wireless access technologies. However, mobile IP in its basic form inherits the IP incapability to provide QoS guarantees. This results in mobile IP's lack of support for seamless intradomain mobility. This article surveys extensions that have been proposed to enhance the QoS functionality of mobile IP. It gives a brief overview of mobile IP and Internet QoS paradigms, and describes their general shortcomings with regard to QoS and mobility, respectively. It then discusses the extensions that have been proposed in the literature and provides a qualitative comparison.     

NetCAPE: Enabling Seamless IMS Service Delivery across Heterogeneous Mobile Networks

An evolving wireless world is constantly providing users with a wider set of access technologies to choose from, each with different capabilities and properties. In this world, IMS as defined by 3GPP provides an enabling, standardized multimedia architecture that is access independent, hence, providing service convergence. This trend is accompanied by an increasing number of multimode terminals so that inter-access- system-service continuity gains relevance. This article presents the architectural framework of NetCAPE (networking context aware policy environment), which addresses the optimization of mobility management in such a heterogeneous environment while interacting with IMS applications to enable seamless service delivery across heterogeneous mobile networks; even as the mobility offered by the underlying network remains transparent to IMS applications. Although the focus is on 3GPP-based mobile networks, the framework also incorporates wired access technologies, hence, taking a further step toward fixed mobile convergence (FMC). First results are presented highlighting the improvements gained by applying NetCAPE concepts.     

5G meets satellite: Non-terrestrial network architecture and 3GPP

With 3GPP Release-17, global 5G standards now support non-terrestrial mobile networks comprising radio access network, terminals, and core network. This enables multi-vendor interoperability as well as interoperability with 3GPP-compliant 5G systems. This paper describes the key features enabling the NG-RAN architecture defined for 5G to support non-terrestrial networks. Starting from a general overview of NG-RAN and of the new paradigms of NTN, we introduce the NTN functionality in NG-RAN specifications with respect to feeder link switchover, cell handling, terminal registration, and OAM aspects. We also discuss different scenarios combining satellite access with 3GPP-defined core networks. We also describe some further enhancements expected to be seen in the next 3GPP release (Rel-18). We believe current and upcoming 3GPP work for NTN represents a solid basis on which 5G satellite networks can be built in the upcoming future.     

LTE Part I: Core network

Current cellular networks based on Third Generation Partnership Project (3GPP) and 3GPP2 technologies provide evolution from circuit-switched technologies, originally developed for voice communications, to packetswitched technologies. Next-generation networks need to deliver IP-based services (voice, video, multimedia, data, etc.) for all kinds of user terminals while moving between fixed (fiber, DSL, cable) and wireless (3GPP-based, 3GPP2-based, IEEE-based) access technologies, and roaming between various operator networks. Users expect the network to originate, terminate, and maintain a session while the user is moving and roaming. Services have to be delivered to users based on serving network functionality (quality of service [QoS], bandwidth, etc.), availability, and user preferences. The network and users must be protected through various authentication, encryption, and other security mechanisms at the access, network, and application layers. Mobility has to be provided through coordinated link, network, and application layer mobility mechanisms that ensure user expectations of service performance are met. Requirements on the radio technology include improved performance as well as reduced system and device complexity. 3GPP Release 8 specifies the architecture to meet the above requirements.     

一种WLAN与LTE网络融合方案

3GPP23.234规范中提出研究WLAN等非3GPP接入EPC的互通架构。用户终端(UE)可以通过WLAN,以S2a、S2b或S2c等接口接入EPC。文章针对安全性低和改造复杂的问题,提出WGW-S2a融合网络架构——部署WGW网元支持EAP-AKA认证报文转发并具有MAG功能,采用EAP-SIM/AKAover802.1x实现安全的统一认证,WLAN用户接入EPC时IP地址分配由PDNGW分配。在WGW-S2a融合网络架构中,WLAN网络与EPC之间的接口仍然符合3GPP标准的S2a接口。     

Improvements to seamless vertical handover between mobile WiMAX and 3GPP UTRAN through the evolved packet core - [LTE part II: 3GPP release 8]

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 [1, 2], 3GPP legacy systems (i.e., Global System for Mobile communications and Universal Mobile Telecommunications System) [3, 4], and 3G Long Term Evolution [5, 6] is presented, which is based on existing optimized handover techniques between mobile WiMAX and 3GPP accesses [7?9]. 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 [7?9]. 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.     

Radio interface protocols and radio resource management procedures for 5G new radio non-terrestrial networks

In Release 17, 3GPP introduced adaptations and enhancements to the 5G new radio (NR) specification to support non-terrestrial networks (NTNs) operation. The main challenges were due to long propagation delays, especially in GEO deployments, and the movement of the satellites in LEO deployments. In this paper, we give an overview of the protocol adaptations to support NTNs. The main user plane protocol adaptations include changes to random access and hybrid automatic repeat request to due long propagation delays. The control plane protocol adaptations include a variety of mobility related enhancements for user equipment.     

Improving session continuity through user mobility tracking for EPS inter‐serving gateway handover

The Evolved Packet System (EPS) is standardized to support a common IP‐based core network with heterogeneous radio accesses in the latest 3GPP release. In the EPS, the Policy and Charging Control (PCC) framework provides dynamic policy control combined with real‐time charging management. Long core network signaling for PCC degrades session continuity performance during handover. In this paper, we investigate the handover for an EPS session. Based on the results, we propose a proactive scheme along with a user mobility tracking model to improve session continuity. More specifically, our proposed scheme attempts to reduce PCC reauthorization signaling delay during the handover procedure. Then, we formulate a Markov process to model the user mobility pattern and to derive the session continuity probability. Numerical results show that our scheme can significantly keep the session continuity at a user acceptable level even when the mobility pattern is high. We also provide guidelines for operators to set up the network configuration parameters according to various traffic conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

WLAN与3GPP无线互操作研究进展与展望

终端如何在3GPP与WLAN中选择最优网络接入并进行业务分流是WLAN与3GPP互操作中需要解决的重要问题。传统3GPP与WLAN互操作主要集中在核心网层面,无法考虑无线网络负载,容易造成网络负荷不均,用户体验降低。3GPP R12阶段在RAN2开展了WLAN与3GPP无线互操作研究,定义了一系列无线接入网辅助参数和无线接入网规则以增强WLAN与3GPP在无线的接入网选择和业务分流方案,有效提高了用户体验以及运营商对于WLAN的控制能力,为WLAN与3GPP网络深入融合提供解决方案。     

UMTS-WLAN异构网络互联的方案研究

通用移动通信系统(UMTS)为移动数据用户提供了较广阔的覆盖范围,而无线局域网(WLAN)能在局部热点地区提供较高的接入带宽.两种网络的显著优势能够相互结合,为处于异构网络覆盖地区的用户提供网间无缝连接.本文总结了目前UMTS-WLAN互联的三种实施方案:移动IP、互联网关和仿真器.在分别介绍三种方案的体系架构、互联机制和切换流程后从互联层次、信令和数据流向、对现有网络的改造、安全认证机制及用户管理方式等不同层面分析三种方案的特点.     

Effective session key distribution for secure fast handover in mobile networks

In this paper, we introduce a session key distribution mechanism for fast secure handover in wireless mobile networks. The proposed mechanism is based on the stream control transmission protocol in where a mobile node actively changes its IP address without its connection loss. When a mobile node moves between different access routers, the required session key at a new access router is distributed previously through the tunnel established between the previous access router and the new access router. Due to the reduced key distribution time, the mobile node achieves its secure seamless handover. The provided performance analysis proves that the proposed mechanism provides the reduced signaling cost compared to existing mobility protocols. In addition, the proposed mechanism reduces the handover latency so that the reduced amount of packet loss provides the stable handover performance for real-time applications.     

An access-aware pricing strategy for the evolved packet system

The evolved packet system (EPS) integrates third generation partnership project (3GPP) and non-3GPP wireless access networks to provide mobile users with ubiquitous access to a diverse set of multimedia services. As we know, 3GPP and non-3GPP access networks differ significantly with respect to bandwidth capacity, coverage range, and service cost. It is crucial to enable efficient load balancing between 3GPP and non-3GPP access networks to improve resource utilization, and still maximize revenue generation. From an economic point of view, pricing plays an important role in achieving load balancing in the EPS. This paper proposes an access-aware pricing strategy for the EPS to achieve load balancing between 3GPP and non-3GPP access networks and to maximize revenue generation for network operators. In addition, this paper develops an analytical model for the system using the proposed access-aware pricing strategy. With the analytical model, this paper also proposes an iterative method for determining the optimal pricing that maximizes revenue generation in the EPS. The analytical model is verified by simulation.     

支持无线移动因特网的IP移动性框架

主要介绍了用户的移动性给IP网络带来的挑战，给出了IP核心网的不同接入网如何实现移动性的一个设想(IP移动性框架)，详细讨论了它的4个抽象实体的功能。该结构框架确立了支持用户在基于IP核心网的不同类型接入网内的移动性所必需的移动性管理部分，能确保用户在自由漫游的时候接入Web。此外，它还可以使各种手持设备和笔记本电脑从一栋建筑物移动到另一栋建筑物，或从一个网络到另一个网络，同时能够跨越有线和无线网络。     

Evaluation of Interoperability Criteria and Mechanisms for Seamless Inter-Working Between UMTS-HSDPA and WLAN Networks Enhanced with MIMO Techniques

This article proposes criteria and mechanisms that achieve seamless inter-working between the multi-radio access technologies that will compose the fourth-generation (4G) wireless mobile environment. We address the problem of incorporating system interoperability in order to provide the user with seamless mobility across different radio access technologies; namely we focus on inter-working UMTS-High Speed Downlink Packet Access (HSDPA) and WLAN networks, as these two networks are believed to be major components of the 4G wireless network. Interoperability results in providing the user with a rich range of services across a wide range of propagation environment and mobility conditions, using a single terminal. Specifically, the article aims at defining the criteria and mechanisms for interoperability between the two networks. Our approach considers the use of Cost functions to monitor the essential parameters at the system level in order to trigger an interoperability procedure. Initial user assignment and inter-system handover are considered the incidents that initiate the interoperability algorithm execution. The overall objective of this work is to assess the performance of our developed interoperability platform and to optimize system performance by guarantying a minimum QoS requirement and maximizing network capacity.     

Moving toward seamless mobility: state of the art and emerging aspects in standardization bodies

The challenge to provide seamless mobility in the near future emerges as a key topic in various standardization bodies. This includes first of all the support of seamless handover between homogeneous networks. Distinct technologies—such as IEEE 802.11WLANs (Wi-Fi) and IEEE 802.16 MANs WiMAX—have recently augmented such support to existing standards to enable seamless homogeneous handover. Cellular networks, in contrast, already included this inherently from the start. Currently considerable effort goes into coupling of different radio access technologies. Therefore, the second key topic in standardization is seamless heterogeneous handovers. IEEE, IETF, as well as 3GPP consider different approaches toward architectures and protocols enabling seamless mobility management. In this work, we discuss recent and on-going standardization activities within IEEE, IETF, and 3GPP toward seamless homogeneous as well as heterogeneous mobility support.