Universal Mobile Telecommunications System Networks Research Articles

A tabu search algorithm for the global planning problem of third generation mobile networks

In this paper, we propose a tabu search (TS) algorithm for the global planning problem of third generation (3G) universal mobile telecommunications system (UMTS) networks. This problem is composed of three NP-hard subproblems: the cell, the access network and the core network planning subproblems. Therefore, the global planning problem consists in selecting the number, the location and the type of network nodes (including the base stations, the radio network controllers, the mobile switching centers and the serving GPRS (General Packet Radio Service) support nodes) as well as the interconnections between them. After describing our metaheuristic, a systematic set of experiments is designed to assess its performance. The results show that quasi-optimal solutions can be obtained with the proposed approach.

On the design and implementation of a RISC processor extension for the KASUMI encryption algorithm

Modern cellular networks allow users to transmit information at high data rates, have access to IP-based networks deployed around the world, and access to sophisticated services. In this context, not only is it necessary to develop new radio interface technologies and improve existing core networks to reach success, but guaranteeing confidentiality and integrity during transmission is a must. The KASUMI block cipher lies at the core of both the f8 data confidentiality algorithm and the f9 data integrity algorithm for Universal Mobile Telecommunications System networks. KASUMI implementations must reach high performance and have low power consumption in order to be adequate for network components. This paper describes a specialized processor core designed to efficiently perform the KASUMI algorithm. Experimental results show two orders of magnitude performance improvement over software only based implementations. We describe the used design technique that can also be applied to implement other Feistel-like ciphering algorithms. The proposed architecture was implemented on a FPGA, results are presented and discussed.

Nonlinear complex behaviour of TCP in UMTS networks and performance analysis

Nonlinear dynamic behaviour of transmission control protocol (TCP) in universal mobile telecommunications system (UMTS) networks is proposed. The dynamic characteristics of TCP are explored using the fundamentals of chaos theory, and the occurrence of chaotic behaviour in relation to the feedback that is received (packet drops, packet delays) by TCP from the network is explained theoritically. To validate the concept proposed, a model of the UMTS network is built and simulated under various user traffic loads. Using standard chaos methodology, it was found that inside the UMTS the TCP exhibits aperiodicity and sensitivity to initial conditions that are inherent characteristics of chaos. In particular, simulation results illustrate that as the traffic load increases, the behaviour of the network ranges from periodically stable to chaotic, with a direct impact on the quality of service of the network.

Proposal of a Fixed Communication System Sharing the Bandwidth of an Existing Personal Communication Network

This paper deals with the proposal and performance evaluation of a fixed microwave communication (FMC) system that shares the same bandwidth with a wireless personal communication network. In particular, the focus here is on the case of an existing universal mobile telecommunication system (UMTS) network for which an FMC system is considered to provide a wireless connection between a remote base station not having the possibility of a wired connection to the core network and a base station having this possibility (a core network access point). This facility is of special interest in a dense urban environment or whenever a wired connection is prohibitive for service providers due to its implementation cost or lack of frequency spectrum. The mutual interference effects between the FMC systems and the existing UMTSs are investigated by focusing on typical application scenarios. A receiving scheme where interference signals are first detected and then canceled from the other received signals is proposed. The performance of the two interfering systems has been evaluated in terms of bit error rates (BERs) both by means of an analytical approach and computer simulations. The obtained results clearly demonstrate the effectiveness of the proposed method, in particular, by allowing efficient bandwidth sharing between the FMC system and the existing UMTS network.

Admission Control in UMTS Networks based on Approximate Dynamic Programming

This paper presents a Connection Admission Control (CAC) algorithm for Universal Mobile Telecommunications System (UMTS) networks based on an Approximate Dynamic Programming (ADP) approach. To deal with the non-stationary environment due to the timevarying statistical characteristics of the offered traffic, the admission policy has to be computed periodically based on on-line measurements. If standard algorithms are used, the optimal policy computation is excessively time-consuming to be performed on-line. Thus, an ADP approach for the computation of a sub-optimal admission policy is proposed. TheADPapproach is based (i) on the reduction of the policy space, and (ii) on an approximated state-space aggregation. Theoretical results and numerical simulations show the effectiveness of the proposed approach, which is currently being implemented in a real UMTS testbed.

EVALUATION OF QOS IN UMTS BACKBONE NETWORK BY USING DIFFERENTIATED SERVICES

A distinguishing feature of the Universal Mobile Telecommunications System (UMTS) is the support of different levels of quality of service (QoS) as required by subscribers and their applications. To provide QoS, the UMTS backbone network needs an efficient QoS mechanism to provide the demanded level of services on UMTS network. We implement a model to investigate end-to-end quality of service (QoS) provisioning approaches for UMTS networks in a DiffServ IP network environment. The effort was put on QoS classes mapping from DiffServ to UMTS, Access Control, buffering and scheduling optimization. The DiffServ Code Point was utilized in the E2E UMTS QoS provisioning to differentiate different types of traffic. We hybridized our work by applying Resource reservation protocol (RSVP) in routers and hosts. The main advantages and drawbacks are discussed. We found that our proposed model (hybridized model (DiffServ/RSVP)) improves the end-to-end delay and end-to-end variation compared with DiffServ model only, and it is superior to DiffServ regarding to throughput, utilization and packet loss ratio. The overall work guarantees the E2E QoS parameters of each service class, especially for real-time applications and improved the bandwidth utilization. Simulation results show that DiffServ can be an effective candidate for UMTS backbone bearer service.

Link Error Analysis and Modeling for Video Streaming Cross-Layer Design in Mobile Communication Networks

Particularly in wireless communications, link errors severely affect the quality of the services due to the high error probability and the specific error characteristics (burst errors) in the radio access part of the network. In this work, we show that thorough analysis and appropriate modeling of radio-link error behavior are essential to evaluate and optimize higher layer protocols and services. They are also the basis for finding network-aware cross-layer processing algorithms which are capable of exploiting the specific properties of the link error statistics, such as predictability. This document presents the analysis of the radio link errors based on measurements in live Universal Mobile Telecommunication System (UMTS) radio access networks as well as new link error models originating from that analysis. It is shown that the knowledge of the specific link error characteristics leads to significant improvements in the quality of streamed video by applying the proposed novel network- and content-aware cross-layer scheduling algorithms. Although based on live UMTS network experience, many of the conclusions in this work are of general validity and are not limited to UMTS only.

An improved handover algorithm based on signal strength plus distance for interoperability in mobile cellular networks

In future generation mobile cellular systems, position location of mobile terminal is expected to be available. In this paper, we propose an initiation algorithm for intersystem handover based on the combination of position location of mobile terminal and the absolute signal strength thresholds. Global System for Mobile communication (GSM) and Universal Mobile Telecommunication Systems (UMTS) networks are considered for interworking. The proposed algorithm reduces the handover rate by around 50% and thus improves the network resource efficiency as compared to that based on signal strength thresholds only.

QoS control for streaming service in UMTS networks

This paper addresses the end-to-end quality of service (QoS) architecture and mechanisms for Universal Mobile Telecommunications System (UMTS) networks. It presents specific QoS control mechanisms and algorithms for network performance engineering for real time services, in particular streaming applications. The paper concentrates on QoS control in the UMTS terrestrial radio access network (UTRAN) since it is often a bottleneck in end-to-end UMTS bearer performance, especially in the initial stages of network deployment. It discusses several QoS implementation mechanisms, including air interface resource and congestion control, call admission control, mobility control, backhaul bandwidth management, and network element queuing control. Simulation results are presented to show the effectiveness of these controls, and ways they can be used to guarantee streaming bearer performance. In addition, real measurement results are given for a commercial end-to-end UMTS network. © 2007 Alcatel-Lucent.

The UMTS base station router

This paper reviews the Alcatel-Lucent Universal Mobile Telecommunications System (UMTS) base station router (BSR)—a radio access network (RAN) and core network (CN) in a single network element. While typical cellular UMTS networks are built from a plethora of network elements and are maintained in a hierarchical fashion, the BSR combines all functions of a radio access network and core network in a single network element. Moreover, the BSR can be considered a wireless edge router that bridges between cellular-specific wireless transmissions and IP networks. Integrating RAN functionality in a single network element presents the following technical advantages: improving the responsiveness (i.e., latency reductions), reducing the complexity, and improving the fault tolerance of the system. © 2007 Alcatel-Lucent.

Design and implementation of an integrated accounting architecture for distributed UMTS and WLAN networks

Accounting for resource and service usage in communication networks forms the basis of network operators' business, and is therefore essential. Within a heterogeneous, multidomain mobile environment of emerging new access technologies, the demand for a distributed accounting infrastructure becomes more relevant. Driven by the analysis of current accounting solutions in Universal Mobile Telecommunications System (UMTS) and Wireless Local Area Networks (WLAN) networks, the newly developed approach presents an integrated accounting architecture based on the Diameter protocol, forming a flexible basis for charging UMTS and WLAN communication services. The system developed is described, discussed and evaluated by a prototypical implementation.

Addressing of software downloads to reconfigurable terminals in UMTS

Over-the-air software download is a key enabler for many aspects related to the reconfiguration of terminals based on software-defined radio (SDR). Different mechanisms for advertising the availability of software enhancements to a group of SDR terminals in universal mobile telecommunication system networks are evaluated. In order to exploit efficiencies in terms of transmission and processing, addressing strategies that allow the subsequent download to be performed in a multicast fashion are considered. A novel scheme for advertising software to only those terminals that are targeted by the download is introduced. On the basis of cost analysis, it is shown that the proposed scheme performs favourably compared with other viable schemes for performing software upgrade announcements.

Authentication mechanism over the integrated UMTS network and WLAN platform using the cross-layer bootstrap

The 3G mobile data network provides always-on and ubiquitous connectivity for subscribers. Although the service coverage area in wireless local area network (WLAN) is much smaller than that in a 3G mobile data network, the data transmission rate in WLAN can be from 2 to 54 Mbps, which is much faster than 3G mobile network. Obviously, the relationship between the 3G mobile data network and WLAN is complementary in terms of service coverage and data transmission rate. Therefore integration of 3G mobile network and WLAN can offer subscribers higher speed wireless service in hot spots and ubiquitous connectivity in 3G mobile data network. An authentication mechanism over the loose coupled integration mechanism using a cross-layer bootstrap is proposed. The benefits of the proposed mechanism are (a) integrating Universal Mobile Telecommunication System network and WLAN using the existing protocols defined in 3GPP, IETF and IEEE 802.11i, (b) the use of the Extension Authentication Protocol authentication method is flexible, (c) reduction of the authentication signalling when a subscriber roams from one access point (AP) to another AP and (d) user identity privacy protection.

Scalable rate control for video transmission over UMTS

AbstractThis paper proposes a mechanism for the congestion control for video transmission over Universal Mobile Telecommunications System (UMTS). Our scheme is applied when the mobile user experiences real time multimedia content and adopts the theory of a widely accepted rate control method in wired networks, namely equation‐based rate control. In this approach, the transmission rate of the multimedia data is determined as a function of the packet loss rate, the round trip time and the packet size and the server explicitly adjusts its sending rate as a function of these parameters. Through a number of simulations and experiments we validate the correctness and measure the performance and efficiency of the mechanism. A first level of evaluation is carried out using the ns‐2 simulator. A second level then validates the proposed mechanism in real world traffic scenarios by performing experiments in a commercial UMTS network. Copyright © 2006 John Wiley & Sons, Ltd.

QoS 보장을 위한 UMTS와 WLAN의 인터워킹 구조

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.

The multimedia broadcast/multicast service

AbstractThis article provides an overview of the multimedia broadcast/multicast service (MBMS) for universal mobile telecommunications system (UMTS) networks. We first outline the features of UMTS networks as defined by the 3rd generation partnership project (3GPP) in order to provide a background for the discussion to follow. We then present the overall MBMS architecture, the services that it provides to the users and the differences between the broadcast and multicast options. The implementation details of MBMS are explained in terms of the modifications needed to the network, the new signaling procedures required and the impact of MBMS on the radio part of the network. We then describe how the security architecture of UMTS is used to support content protection and key distribution for MBMS groups. We evaluate the prospects of MBMS by comparing it first with IP multicast and then with DVB‐H, considered by many to be the closest competitor of MBMS. Finally, we conclude with a discussion of the technical and business challenges still faced by MBMS. Copyright © 2006 John Wiley & Sons, Ltd.

Web browsing optimization over 2.5G and 3G: end‐to‐end mechanisms vs. usage of performance enhancing proxies

Abstract2.5 Generation (2.5G) and Third Generation (3G) cellular wireless networks allow mobile Internet access with bearers specifically designed for data communications. However, Internet protocols under‐utilize wireless wide area network (WWAN) link resources, mainly due to large round trip times (RTTs) and request‐‐reply protocol patterns. Web browsing is a popular service that suffers significant performance degradation over 2.5G and 3G. In this paper, we review and compare the two main approaches for improving web browsing performance over wireless links: (i) using adequate end‐to‐end parameters and mechanisms and (ii) interposing a performance enhancing proxy (PEP) between the wireless and wired parts. We conclude that PEPs are currently the only feasible way for significantly optimizing web browsing behavior over 2.5G and 3G. In addition, we evaluate the two main current commercial PEPs over live general packet radio service (GPRS) and universal mobile telecommunications system (UMTS) networks. The results show that PEPs can lead to near‐ideal web browsing performance in certain scenarios. Copyright © 2006 John Wiley & Sons, Ltd.

Seamless Handoff Scheme Based on Pre-registration and Pre-authentication for UMTS–WLAN Interworking

Interworking issues between Universal Mobile Telecommunication System (UMTS) and Wireless Local Area Network (WLAN) have become a great matter of interest as an increasing number of mobile internet users require broadband wireless access to IP services in the wide area. In this paper, we present a practical UMTS---WLAN interworking architecture based on 3GPP standards and propose a seamless handoff scheme that guarantees low delay and low packet loss during UMTS---WLAN handoff. For low handoff delay, the proposed handoff scheme performs pre-registration and pre-authentication processes before layer 2 handoff. Moreover, it uses packet buffering and forwarding functions in order to reduce packet loss during the handoff period. On the above basis, detailed signaling procedures are presented, together with system requirements when a mobile terminal moves from UMTS to WLAN and vice-versa. Numerical results show that the proposed scheme performs well with respect to signaling cost, handoff delay, and packet loss compared with conventional schemes.

Global expansion model for mobile networks

In this letter, we propose a global model to solve the expansion problem of universal mobile telecommunications system (UMTS) networks. Since the network expansion problem is a generalization of the network design problem, the proposed model can be used for the design of UMTS networks. The proposed model deals simultaneously with the cell, the access network and the core network planning subproblems. This global approach has the advantage of providing better results since, in general, optimal solutions to all subproblems do not provide an optimal solution to the global problem. Moreover, this model fits real life situations in which mobile users have the choice to subscribe or to leave a service providers. Numerical results are presented and analyzed

A Novel Location Management Scheme for Cellular Overlay Networks

In Beyond Third Generation (B3G) wireless communications, multiple overlays of wireless access networks may cooperate to allow a user access to novel services, the future demands of which will significantly increase the load on location management systems within the networks. In this paper, we introduce the reader to our novel proposals for providing efficient Mobile Terminal (MT) Location Discovery and Paging across an inter-worked network consisting a Digital Video Broadcast (DVB) network and Universal Mobile Telecommunication System (UMTS) network. We further present numerical and simulation analyzes of our scheme. The numerical and simulation results allow broadcast and cellular network operators to configure their inter-worked system to reduce location management and paging costs whilst controlling average latency. Our results demonstrate that our UMTS LA plus DVB paging schemes offer promise for efficient MT discovery in an inter-network environment that includes uni-directional broadcast network such as DVB; under realistic scenarios we achieve a minimum 4 times reduction in paging cost across the inter-network compared with independent paging systems. Furthermore, we briefly introduce further aspects of research that must be addressed in order to fully evaluate our proposals.