Christer Åhlund - Academia.edu (original) (raw)
Papers by Christer Åhlund
Telecommunication Systems, 2008
Mobility is gaining a tremendous interest among Internet users and wireless access networks are i... more Mobility is gaining a tremendous interest among Internet users and wireless access networks are increasingly being installed to enable mobile usage. Internet mobility requires solutions to move between access networks with maintained network connectivity. Seamless mobility in turn means that the experience of using a service is unaffected while being mobile. Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. Further, roaming between network service providers may take place. To enable mobile nodes to move between access networks within as well as between network service providers with minimal disruption, nodes should be able to maintain multiple active network connections. With the usage of multihomed nodes, seamless mobility can be achieved in already installed infrastructures, not providing mobility support. Mobility in heterogeneous access networks also requires network selections that scale for services. In this article we propose an architecture where application service providers and network service providers define service levels to be used by a mobile node and its user. The user selects a service and the service level from an application service provider. When performing access network selection, information received as part of an application service level will be used to find a network that supports the service required. The performance of available access networks will be monitored and considered when making the decision. Our proposed architecture provides solutions to move flows between interfaces in realtime based on network performance, quality of service sig
With the recent developments in wireless networks, different radio access technologies are used i... more With the recent developments in wireless networks, different radio access technologies are used in different places depending on capacity in terms of throughput, cell size, scalability etc. In this context, mobile users, and in particular highly mobile users and vehicular networks, will see an increasing number and variety of wireless access points enabling Internet connectivity. Such a heterogeneous networking environment needs, however, an efficient mobility management scheme offering the best connection continuously. In this paper, a mobility management architecture focusing on efficient network selection and timely handling of vertical and horizontal handovers is proposed. The solution is based on Mobile IP where handover decisions are taken based upon calculations of a metric combining delay and delay jitter. For efficiency reasons, the frequency of binding updates is dynamically controlled, depending on speed and variations in the metric. The dynamic frequency of binding updates helps the timely discovery of congested access points and cell edges so as to allow efficient handovers that minimize packet drops and handover delays. Results show that the overall signaling cost is decreased and changes in networking conditions are detected earlier compared to standard Mobile IP. Keywords-Mobility management; heterogeneous networking environments; highly mobile users; vehicular networks I. INTRODUCTION Mobility support for highly mobile users and vehicular networks is an emerging research area. Besides intra-vehicular and vehicle-to-vehicle communication vehicle-to-infrastructure communication is an important subarea being investigated in current research. Another important development field is the global deployment of new radio access networking technologies including both dedicated technologies for vehicular communication and more general solutions for wireless communications. The IEEE 802.11p-based Dedicated Short Range Communication, DSRC, [1] is an example of the former type. General solutions include other IEEE standards like the different WLAN standards 802.11a, 802.11b, and 802.11g [2], the mobile WiMAX 802.16e [3] standard, as well as the IEEE 802.20 Mobile Broadband for Wireless Access [4] standard. Besides those IEEE standards, the telecommunications industry is improving the 2.5G and 3G standards offering higher capacities to their customers.
In the future, mobile users will have the possibility to use a variety of wireless access network... more In the future, mobile users will have the possibility to use a variety of wireless access networks simultaneously making the vision "Always best connected" come true. The Internet Protocol (IP) will most likely be the least common divisor allowing service providers to deploy services in a unified way regardless of access network type (being wired or wireless). The 3GPP-led development of the IP Multimedia Subsystem (IMS) is a promising step towards the vision. However, there are a number of obstacles along this way forward. Various deployment difficulties related to already installed base of user and infrastructure equipment and service providers protecting their old investments are the most common obstacles. In addition to those reasons, somewhat conservative regulatory authorities, shortcomings in digital rights management, multiple standardization bodies proposing non-aligned solutions, as well as non-uniformed and non-optimized use of radio spectrum do not improve the speed of change.
Telecommunication Systems, 2008
Mobility is gaining a tremendous interest among Internet users and wireless access networks are i... more Mobility is gaining a tremendous interest among Internet users and wireless access networks are increasingly being installed to enable mobile usage. Internet mobility requires solutions to move between access networks with maintained network connectivity. Seamless mobility in turn means that the experience of using a service is unaffected while being mobile. Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. Further, roaming between network service providers may take place. To enable mobile nodes to move between access networks within as well as between network service providers with minimal disruption, nodes should be able to maintain multiple active network connections. With the usage of multihomed nodes, seamless mobility can be achieved in already installed infrastructures, not providing mobility support. Mobility in heterogeneous access networks also requires network selections that scale for services. In this article we propose an architecture where application service providers and network service providers define service levels to be used by a mobile node and its user. The user selects a service and the service level from an application service provider. When performing access network selection, information received as part of an application service level will be used to find a network that supports the service required. The performance of available access networks will be monitored and considered when making the decision. Our proposed architecture provides solutions to move flows between interfaces in realtime based on network performance, quality of service sig
With the recent developments in wireless networks, different radio access technologies are used i... more With the recent developments in wireless networks, different radio access technologies are used in different places depending on capacity in terms of throughput, cell size, scalability etc. In this context, mobile users, and in particular highly mobile users and vehicular networks, will see an increasing number and variety of wireless access points enabling Internet connectivity. Such a heterogeneous networking environment needs, however, an efficient mobility management scheme offering the best connection continuously. In this paper, a mobility management architecture focusing on efficient network selection and timely handling of vertical and horizontal handovers is proposed. The solution is based on Mobile IP where handover decisions are taken based upon calculations of a metric combining delay and delay jitter. For efficiency reasons, the frequency of binding updates is dynamically controlled, depending on speed and variations in the metric. The dynamic frequency of binding updates helps the timely discovery of congested access points and cell edges so as to allow efficient handovers that minimize packet drops and handover delays. Results show that the overall signaling cost is decreased and changes in networking conditions are detected earlier compared to standard Mobile IP. Keywords-Mobility management; heterogeneous networking environments; highly mobile users; vehicular networks I. INTRODUCTION Mobility support for highly mobile users and vehicular networks is an emerging research area. Besides intra-vehicular and vehicle-to-vehicle communication vehicle-to-infrastructure communication is an important subarea being investigated in current research. Another important development field is the global deployment of new radio access networking technologies including both dedicated technologies for vehicular communication and more general solutions for wireless communications. The IEEE 802.11p-based Dedicated Short Range Communication, DSRC, [1] is an example of the former type. General solutions include other IEEE standards like the different WLAN standards 802.11a, 802.11b, and 802.11g [2], the mobile WiMAX 802.16e [3] standard, as well as the IEEE 802.20 Mobile Broadband for Wireless Access [4] standard. Besides those IEEE standards, the telecommunications industry is improving the 2.5G and 3G standards offering higher capacities to their customers.
In the future, mobile users will have the possibility to use a variety of wireless access network... more In the future, mobile users will have the possibility to use a variety of wireless access networks simultaneously making the vision "Always best connected" come true. The Internet Protocol (IP) will most likely be the least common divisor allowing service providers to deploy services in a unified way regardless of access network type (being wired or wireless). The 3GPP-led development of the IP Multimedia Subsystem (IMS) is a promising step towards the vision. However, there are a number of obstacles along this way forward. Various deployment difficulties related to already installed base of user and infrastructure equipment and service providers protecting their old investments are the most common obstacles. In addition to those reasons, somewhat conservative regulatory authorities, shortcomings in digital rights management, multiple standardization bodies proposing non-aligned solutions, as well as non-uniformed and non-optimized use of radio spectrum do not improve the speed of change.