Design and analysis of UMTS-WLAN interoperability and service continuity using the SIP protocol

Interconnection of different access network technologies is an important research topic in mobile telecommunications systems. In this paper, we propose an ns-3 architecture for simulating the interconnection of wireless local area network (WLAN) and Universal Mobile Telecommunications System (UMTS). This architecture is based on the architecture proposed by the Third Generation Partnership Project, being the use of virtual interfaces as its main innovation. In order to demonstrate the value of the proposed simulation framework, we implemented the UMTS and WLAN interconnection considering three joint radio resource management strategies for distributing arriving calls. From the simulations results, we can conclude that the proposed simulation architecture is suitable to test and evaluate performance aspects related to the interconnection and joint management of UMTS and WLAN technologies. Copyright © 2012 John Wiley & Sons, Ltd.

The session initiation protocol (SIP) was used on a large scale as a session signalling protocol to provide legacy as well as new services. The 3rd Generation Partnership Project (3GPP) has decided to use the SIP protocol in the IP multimedia subsystem of future Universal Mobile Telecommunications System (UMTS) networks. If the SIP protocol is used in carrier grade networks, quality of service (QoS) observations are necessary to ensure quality service provisioning. This, in particular, is important since signalling will use multiservice IP transport networks and share its resources with other services. This paper proposes the concept of virtual SIP links (VSLs) that connect two SIP nodes. VSLs can be used to enable QoS provisioning in SIP signalling overlay networks. Methodologies are introduced to specify, define and dimension these virtual connections. The VSL specification uses the well-known concept of leaky buckets. Simple methodologies are established that are based on known results, to calculate message loss probabilities (MLPs) in leaky buckets. A simple, but efficient, queueing scheme is introduced that reduces the required network resources. Simulation results are given to validate the used models and to underline performance advantages for connections that use VSLs.

Wireless local area network (WLAN) systems are typically designed to provide fixed or nomadic access. Using WLAN systems for military purposes raises the question of how WLAN terminals can be utilized in a fully mobile outdoor environment. In these environments, there typically exists multipath propagation with a large delay spread in the radio channel. This paper investigates the effect of terminal movement on the physical layer performance and capacity of IEEE 802.11b WLAN systems in a realistic outdoor mobile environment. Several wireless network interface cards are measured in laboratory conditions using a simulated radio channel. The measurement results indicate that WLAN systems can operate in mobile outdoor environment up to a certain mobile speed, and there are significant differences between equipment from product vendors

In wireless data communication, an advanced nonlinear distortion analysis is required in order to see its effect to the performance of a Radio Frequency (RF) front-end system. This technical paper therefore, reports the effect of third order intermodulation (IM3) distortion on the constellation error (a key measure of modulation quality) in RF transmitter of IEEE 802.11a wireless local area network (WLAN) system. The selected RF transmitter architecture is based on the off-the-shelf components. Advanced Design System (ADS) software has been used for RF transmitter modeling and simulation. The constellation error simulation is based on the IEEE 802.11a standard. As results, two observations have been obtained. First, it is shown that the IM3 distortion in the RF transmitter for IEEE 802.11a WLAN system must be kept in minimum level in order to get lower constellation error. Second, with the same IM3 distortion level, the constellation error is very sensitive to the IM3 distortion at higher data rate (e.g. 54 Mbps) compared to lower data rate (e.g. 6 Mbps).

Dual home agent (DHA)-based location management scheme in integrated cellular–WLAN networks

The authors have analyzed and compared performances of PN (pseudo noise) codes to find optimal PN codes which can be used in a DS/SS (direct sequence/spread spectrum) wireless LAN (local area network) system over a multipath fading channel. A wireless LAN system is susceptible to multipath fading that gives rise to intersymbol interference. The authors have analyzed and compared performances of Barker sequences with those of Gold sequences. As results, Barker sequences are better than Gold sequences for DS/SS wireless LAN systems, from the SNR and BER points of view.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

IntroductionThe popularity of mobile communication systems has increased remarkably during the last decade and the market demand still continues to increase.As a fundamental part of these systems, antenna is one of the most important design issues in modern mobile communication units.Although there are several similar definitions, an antenna can be mainly described as a device, which transforms the electromagnetic waves in an antenna to radiating waves in an unbounded medium such as air in transmitting mode and vice versa in receiving mode.Because antennas are dependent on frequency, they are designed to operate for certain frequency bands.The rapid growth of mobile communication systems has forced to the use of novel antennas for base and mobile station applications (mobile phone, notebook computer, personal digital assistants (PDA), etc.).Earlier, mobile systems were designed to operate for one of the frequency bands of 2G (second generation) systems, which are Digital Cellular System (DCS), Personal Communications Service (PCS) and Global System for Mobile Communications (GSM) networks.Currently, many mobile communication systems use several frequency bands such as GSM 900/1800/1900 bands (890-960 MHz and 1710-1990 MHz); Universal Mobile Telecommunication Systems (UMTS) and UMTS 3G expansion bands (1900-2200 MHz and 2500-2700 MHz); and Wi-Fi (Wireless Fidelity)/Wireless Local Area Networks (WLAN) bands (2400-2500 MHz and 5100-5800 MHz) where the list of frequently used frequency bands is given in Table 1 ( Best, 2008).Conventionally, because a single antenna can not operate at all of these frequency bands of mobile communication, multiple different antennas covering these bands separately should be used.However, usage of many antennas is usually limited by the volume and cost constraints of the applications.Therefore, multiband and wideband antennas are essential to provide multifunctional operations for mobile communication.A multiband antenna in a mobile communication system can be defined as the antenna operating at distinct frequency bands, but not at the intermediate frequencies between bands.For example, a triple band antenna for GSM 900/1800/1900 bands can cover the frequency bands 890-960 MHz and 1710-1990 MHz (Ali et al., 2003); however, it does not operate properly at the frequencies such as 1200 MHz or 2500 MHz.On the other hand, a wideband antenna operates at every frequency points within a given frequency band.For example, a wideband antenna covering UMTS, extended UMTS and WLAN 2400 bands functions at every frequency points www.intechopen.com

In recent years, advances in wireless local area network (WLAN) systems have led to large increases in the transmission speed. The IEEE 802.11ac standard allows for very high transmissions by using multi-user multiple input multiple output (MU-MIMO) techniques in the physical (PHY) layer. However, the transmission efficiency is decreased by the channel state information (CSI) estimation algorithm in the medium access control (MAC) sub-layer. Massive MIMO transmission has attracted attention as a new technology for wireless communication in 5th-generation mobile communication systems (5G). We propose a novel access control scheme for multi-beam massive MIMO technology called overhead-less access control. The proposed scheme allows random access control without CSI estimation for massive MIMO technology. Thus, it greatly reduces the overhead of the MAC sub-layer and improves the transmission efficiency. The proposed scheme can be used to control new massive MIMO systems. We evaluated our proposed overhead-less access control scheme for multi-beam massive MIMO transmission in WLAN systems.

An integrated design of antennas and diplexers for dual-band wireless local area network (WLAN) systems for the purpose of reducing the component count is reported in this paper. Two antenna structures are used in this design. One is the sleeve monopole antenna, and the other is a novel tapered bent folded monopole. The novel tapered bent folded monopole has a bandwidth of 12.5% in the 2.4 GHz WLAN band and 32.4% in the 5 GHz WLAN band. The proposed integrated structures of antennas and diplexers can meet the requirements of the 2.4 GHz and 5 GHz WLAN systems.

This letter addresses how quality of service (QoS) for Session Initiation Protocol (SIP)-based multimedia sessions can be realized within the 3rd Generation Partnership Project (3GPP) architecture. It discusses a scenario for voice over IP (VoIP) to illustrate how relevant QoS mechanisms and signaling protocols such as SIP, Media Gateway Control Protocol (H.248/Megaco), and the Common Open Policy Service (COPS) interact. Related aspects of the Universal Mobile Telecommunications System (UMTS) access network and the IP Multimedia Subsystem (IMS) are explained.

This paper presents a novel approach towards realizing a unified mobility and session management platform for next generation mobile networks at the core network level. In particular, this framework enables a common platform for interworking between universal mobile telecommunications system (UMTS), CDMA2000 technology, and wireless local area networks (WLANs). Within the proposed interworking architecture, the IP multimedia subsystem (IMS) is used as a universal coupling mediator for real-time session negotiation and management over a mobile IP (MIP) based IP mobility management framework. Despite numerous architectural challenges on how IMS and MIP may contribute for session management and IP mobility, the proposed framework achieves this with minimal changes to the existing standards. The paper concludes by presenting simulation results obtained for validating this model using an OPNET based model.

This article describes a novel architecture signaling network so that an IP Multimedia Subsystem (IMS) user, flying in an aircraft, be able to register with his IMS network of origin and have access to personal services and multimedia, through a Wide-Band Code Division Multiple Access (W-CDMA) link. The proposed architecture integrates the Session Initialization Protocol (SIP), the Network Mobility Basic Support (NEMO BS) protocol and the Mobile Internet Protocol (MIPv6) to enable the usage of IMS services by passenger on board an aircraft, as a type of Aeronautical Passenger Communication (APC) services. In this novel architecture, NEMO and MIPv6 protocols are responsible for the mobility management of smartphones and user notebook and the SIP protocol is responsible for the register and the management of sessions of an IMS user. This novel architecture enables an Air Communication Service Provider (ACSP) be able to supply to an on-board passenger (The IMS user) some APC services through an Universal Mobile Telecommunication System (UMTS). The simulation results indicate the accuracy of the proposed architecture into aeronautical scenarios.

최근 Universal Mobile Telecommunication System (UMTS)와 Wireless Local Area Network (WLAN)의 장점을 효율적으로 사용하기 위한, 두 네트워크의 인터워킹 구조에 대한 연구가 활발히 진행되고 있다. 하지만 UMTS와 WLAN은 그 전송량의 차이가 커서, 전송 품질이 저하되기 쉽다. 그러므로 본 논문에서는 tight coupling을 기반으로 이동성 예측 기법을 이용한 동적인 서비스 품질 (QoS: Quality of Service)을 보장해주기 위한 두 네트워크 간 인터워킹 구조를 제안한다. 또한, 이렇게 제안한 인터워킹 구조를 ns-2로 시뮬레이션 하였으며, 그 결과 제안하는 인터워킹 구조가 기존의 인터워킹 구조에 비해 핸드오프 손실률을 줄이고, 핸드오프 순간 QoS를 제공해주지 않는 방법보다 훨씬 더 많은 양의 패킷을 전송한다는 것을 알 수 있다. Universal Mobile Telecommunications System (UMTS) and Wireless Local Area Network (WLAN) have been developed independently. Then, many researchers have studied UMTS-WLAN interworking architecture for the efficiency. However, the transmission capacity difference of two networks causes the transmission quality degradation. Therefore, this paper proposes a UMTS-WLAN interworking architecture for Quality of Service (QoS). The proposed architecture is based on tight coupling and dynamically guarantees QoS by the mobility prediction method. The proposed architecture is simulated by ns-2. Performance experimental results show that the proposed architecture reduces the handover dropping probability comparing with the existing method and enhances the amount of receiving packets comparing with the method without guaranteeing QoS.

Interworking Universal Mobile Telecommunication System (UMTS) and IEEE 802.11 Wireless Local Area Networks (WLANs) introduce new challenges including the design of secured and fast handover protocols. Handover operations within and between networks must not compromise the security of the networks involved. In addition, handovers must be instantaneous to sustain the quality of service (QoS) of the applications running on the User Equipment (UE). There is a need to design fast and secured handover protocols to operate in UMTS-WLAN interworking architectures. This paper proposes two secured preauthentication protocols in the UMTS-WLAN interworking architectures. Performance analysis of the proposed protocols show superior results in comparison to existing protocols in terms of authentication signaling cost, authentication delay and load on critical nodes involved in the authentication procedure. Additionally, the security of the proposed protocols was verified by the Automated Validation of Internet Security Protocols and Applications (AVISPA) security analyzer.

Over the last couple of years, many heterogeneous wireless access technologies have emerged and they have become an integral part of the Internet. In particular, we have experienced an explosive growth in the use of Wireless Local Area Networks (WLANs) and cellular networking technologies (such as Code Division Multiple Access (CDMA), Universal Mobile Telecommunication System (UMTS), General Packet Radio Service (GPRS)). High mobility of wireless users requires that the underlying heterogeneous network infrastructure provides uninterrupted wireless connectivity and service access anywhere, anytime. An additional requirement that is becoming increasingly important for mobile users is the ability to maintain secure connections while on the move across different wireless access technologies. There are some significant challenges (for example, fast, secure handoffs) that need to be overcome to achieve this goal because there is no single end-to-end security protocol that works across both WLANs and cellular networks. We review the various security protocols currently deployed over WLANs and cellular networks. We discuss some of the most recent research efforts on end-to-end security techniques that have been recently deployed across integrated WLAN-Cellular networks. We highlight some of the main benefits and major limitations associated with each security approach. It is hoped that the security solutions discussed will benefit other researchers and designers working to solve the challenge of providing seamless, secure service access across heterogeneous WLAN/Cellular networks.