Pauline M. L. Chan

Mobility management incorporating fuzzy logic for heterogeneous a IP environment

The next generation in mobility management will enable different mobile networks to interoperate with each other to ensure terminal and personal mobility and global portability of network services. However, in order to ensure global mobility, the deployment and integration of both satellite and terrestrial components are necessary. This article is focused on issues related to mobility management in a future mobile communications system, in a scenario where a multisegment access network is integrated into an IP core network by exploiting the principles of Mobile IP. In particular, attention is given to the requirements for location, address, and handover management. In a heterogeneous environment, the need to perform handover between access networks imposes particular constraints on the type of information available to the terminal and network. In this case, consideration will need to be given to parameters other than radio characteristics, such as achievable quality of service and user preference. This article proposes a new approach to handover management by applying the fuzzy logic concept to a heterogeneous environment. The article concludes with a presentation of mobility management signaling protocols.

Implementation of fuzzy multiple objective decision making algorithm in a heterogeneous mobile environment

Mobile satellite networks are now being utilized to provide complementary service coverage to their terrestrial counterparts. The migration from voice-dominated service delivery to a data-centric environment implies that the choice of one particular access network over another will need to take into account many different criteria, which previously need not have been considered. For this reason, it is important that a suitable decision making algorithm is designed to ensure that all of the different characteristics of the system are taken into account when making the segment selection for a particular service delivery. In this paper, a segment selection algorithm based on the fuzzy multiple objective decision making algorithm is presented. This algorithm is analyzed to show how the overall performance of a multi-access segment network can be improved by varying the relative importance of certain service and network characteristics.

Mobile Internet access for high-speed trains via heterogeneous networks

This paper describes how a heterogeneous network that comprises of satellite and WLAN systems could be implemented in a high-speed train environment to provide Internet access. The focus of the paper is on the design of the network architecture and mobility management procedures. In particular, the implementation of WLAN to complement satellite coverage in various operating environments is investigated. For mobility management, issues related to location and handover management are described. In addition, the paper also elaborates on the use of location detection procedures and antenna diversity in trains to aid the process of handover.

Design and validation of QoS aware mobile internet access procedures for heterogeneous networks

In this paper, the requirements for personal environments mobility are addressed from terminal and network perspectives. Practical mobility and Quality of Service (QoS) aware solutions are proposed for a heterogeneous network, comprising of satellite and terrestrial access networks connected to an IP core network. The aim, in adopting a heterogeneous environment, is to provide global, seamless service coverage to a specific area, allowing access to services independently of location. An important assumption is that nomadic user terminals attached to a particular segment should be able to exchange information with any other terminal connected to the network. This is to ensure transparency of device technology. Different communication scenarios are investigated in support of IPv4 and IPv6 operating on user platforms and over access segments. The heterogeneous network necessitates the need to perform handover between access segments to enable coverage extension and seamless connectivity. Handover procedures are analyzed, and an approach is presented that enables various operation and segment specific parameters to be taken into account when deciding upon the need to perform handover and in selecting the optimum access segment. In order to ensure transparency of network technology, the need for end-to-end QoS support is discussed, bearing in mind the deployment of both IntServ and DiffServ enabled routers in the core network. Following this, a new admission control scheme, named Gauge&Gate Reservation with Independent Probing (GRIP), is proposed. The paper concludes with a description of a laboratory testbed, which has been developed in order to verify the presented procedures, together with performance measurements of the handover and the GRIP algorithms.

Broadband Satellite Multimedia

The broadband satellite multimedia (BSM) architecture standardised by ETSI defines a satellite independent service access point (SI-SAP) interface layer that separates the satellite independent features of the upper layers from the satellite dependant features of the lower layers, and provides a mechanism to carry IP-based protocols over these satellite dependent lower layers. This enables interoperability at the IP layer between satellite systems of different physical and link layers technologies that fully comply with the SI-SAP concept. This study reviews past and current standardisation activities including the BSM quality of service (QoS) architecture, security architecture, network management that have been carried out by the ETSI Technical Committee-Satellite Earth Stations and Systems (TC-SES)/BSM working group and looking into the future to extend current SI-SAP functions that can enhance existing QoS provision and security management capabilities as well as proposing a mobility management architecture that complies with the IEEE 802.21 media independent handover framework to support BSM mobility and to allow integration of satellite networks with fixed and mobile network infrastructures. A service-based network management architecture is also proposed to allow management flexibility and integration of business and operation support functions, paving the way for satellite integration into the Internet of the future.

Fastest-Vehicle Multi-hop Routing in Vehicular Ad hoc Networks

Vehicle to vehicle communication has strong potential to be a mechanism to improve driver’s safety and is now emerging as a prominent research area all over the world. At present, vehicular networks are still not considered to be very efficient because of their rapid topology changes and their highly dynamic structure. However, there has been ongoing and progressive research and development in Vehicular Ad hoc Networks (VANETs) [1] [2] [3] to support vehicle to vehicle communication, particularly in the area of routing in VANETs. In VANETs, routing schemes to reduced overhead and resource consumption is required to ensure successful message transfer within the network. The routing protocol proposed in this paper is based on a multi-hop transfer of a single message by discovering the most suitable vehicle within the transmission range instead of using single hop broadcast (flooding) scheme which results in high packet loss and collision rate. The simulation environment used for proposed algorithm is a tool which combines both network simulator and traffic simulator, known as NCTUns-6.0.

Mobility Management for BSM

The European Telecommunications Standards Institute (ETSI) is currently specifying standards for broadband satellite multimedia (BSM). This paper presents an overview on a possible mobility management (MM) architecture for BSM, where satellite independent access function (SIAF) for handover are defined over the SI-SAP interface to enable upper layer access to lower layers and to connect SIAF with the satellite dependent access function (SDAF). The MM architecture takes into account work currently being carried out in IEEE802.21, where media independent handover function (MIHF) is defined for interworking between heterogeneous 802 networks and between 802 and other terrestrial mobile networks through the support of three services for handover, namely, media independent event services (MIES), media independent command services (MICS) and media independent information services (IIS). The synergy of the IEEE802.21 MIHF with the BSM SI-SAP makes it an ideal reference framework for the development of the BSM mobility management architecture and for the harmonization of future integration between BSM and terrestrial networks.

Performance analysis of mobility procedures in a hybrid space terrestrial IP environment

The emphasis of this paper is on investigating the performance of signalling protocols designed for a mobility management scheme, which uses Mobile IP for inter-segment mobility in a hybrid space and terrestrial environment. Initially, the system architecture, which consists of three wireless access networks attached to an IP backbone, is presented. This is followed by a description of the proposed mobility procedures employed in the system, which aim at minimising modifications to existing satellite and terrestrial network protocols. The mobility procedures are simulated in order to evaluate their performance and determine their effectiveness in an operational environment. Results verify the efficiency of the protocols and show that the additional signalling time introduced by the procedures is minimal.

Design and evaluation of signaling protocols for mobility management in an integrated IP environment

In the future mobile network, satellites will operate alongside cellular networks in order to provide seamless connectivity irrespective of the location of the user. Such a service scenario requires that the next generation of mobility management (MM) procedures are able to ensure terminal and user mobility on a global scale. This paper considers how the principles of Mobile-IP can be used to develop MM procedures for a heterogeneous access network, comprizing of satellite and cellular elements, connected to an IP core network.Initially, the system architecture is described. This is followed by a discussion of issues related to MM, where location, address and handover management are considered. A description of the signaling protocols for macro-mobility using Mobile-IP is then presented, emphasizing the need to minimize the change to the existing access network procedures. Finally, the performance of the protocols is analyzed in terms of the additional signaling time required for registration and handover.

A Reception Based Node Selection Protocol for Multi-hop Routing in Vehicular Ad-hoc Networks

Vehicular Ad hoc networks (VANETs) are large complex networks consisting of vehicles with high speeds and highly dynamic network structure. Multi-hop routing in VANETs is one of the important issues due to frequent topology changes and high mobility of network nodes. Most of the current routing protocols propose broadcast based hop selection for packet transfer where requests are broadcasted until the destination is found in the network. Due to this issue, the channel availability reduces and network congestion and packet delay increases. This paper proposes a reception based node selection (RBNS) technique without broadcasting the request messages to discover the destination node. Neighbouring vehicles keep records of their packet reception rate for nodes within their transmission range and the vehicle with highest reception rate is selected as forwarding hop and assigned as the source in the subsequent region to prevent vehicles from the previous transmission regions from broadcasting the request messages. The algorithm performed best in terms of throughput, packet drop and collision when compared to other algorithm from the literature.