Jari Kellokoski

Efficient Handovers for Machine-to-Machine Communications between IEEE 802.11 and 3GPP Evolved Packed Core Networks

Advances in wireless communication technologies are driving the evolution toward ever faster networks in terms of throughput and latency. At the same time, machine-to machine (M2M) communications is expected to have considerable potential with millions of devices connected within the following years. M2M communications is one of the key capabilities for implementation of the Internet of Things (IoT). Due to this potential, several standard organizations are now focusing on developing enhancements into their standards to support M2M communications. As there is no consensus for the architecture of a general scenario for M2M communications, the heterogeneous mobile ad hoc network (HetMANET) can generally be considered suitable for the M2M challenges. Hence, this calls for the IP mobility management, allowing a device to connect to services and access technologies that are best suited for that need. To examine how-to improve the HetMANET concept using existing standards such as IEEE 802.11 and 3GPP Evolved Packed Core (EPC) this paper introduces a straightforward and energy efficient algorithm for vertical handovers. A reference implementation of the handover concept in Android based vehicular-to-infrastructure is introduced. This reference implementation examines energy and performance efficiency in heterogeneous network environment. In addition, real-life use cases with real life services on top of WLAN and cellular network environments are presented to back up the selected approach.

Real-Life Performance Analysis of Always-Best-Connected Network

Mobile Internet has rapidly evolved in the past years with an ever increasing number of novel technologies and services with a variety of access technologies. Indeed, todays mobile devices often support multiple communication technologies for accessing Internet services. However, they all do not tap the full potential of these capabilities, as users often have to manually select each network, and only one network is used at a time. The concept of Always Best Connected (ABC) allows a person to connect applications using the devices and access technologies that best suit to his or her needs, thereby combining the features of access technologies to provide an enhanced user experience for future Internet. This Always Best Connected scenario has been considered to be complex and to generate a number of requirements, not only for the technical solutions, but also in terms of business relationships between operators and service providers. The Third Generation Partnership Project (3GPP) standardized the Evolved Packet System (EPS), where one of the key features is a support access system selection based on a combination of operator policies, user preference and access network conditions. The standard focuses mainly on the operator point of view, and the user is expected to follow this approach. Nevertheless, the standard offers a number of possibilities where the user-centric approach can improve the ABC network selection over the selection predefined by the operator. This research shows how to design a simple but efficient algorithm for the network selection when implementing an Always Best Connected application for mobile devices. This application works with the EPS standard. A real-life implementation and proof-of-concept performance measurements are presented. This will show that in real-life the simple and straightforward methods can provide efficient solutions for problems known to be complex.

Real-life multipath TCP based make-before-break vertical handover

The emerging of the new technologies results in the situation that the User Equipment (UE) may use multiple interfaces to access the network with multiple technologies, which can be summarized as multihoming in a heterogeneous network. In order to promote the widespread deployment of the UEs, mobile operators should consider the mobility management in the network. The Third Generation Partnership Project (3GPP) standardized the Evolved Packet System (EPS) which among others promotes network based mobility management based on Proxy Mobile IPv6 (PMIPv6) protocol. Multipath TCP provides the ability to simultaneously use multiple paths between peers. This paper examines the use of Multipath TCP as a part of EPS to enable make-before-break vertical handovers. An Android based implementation and performance measurement in a real network environment are presented. The implementation show MPTCP suitability for vertical handovers but certain implementation challenges have to be taken into account. Finally, energy efficiency tradeoff in real-life multipath communication is made visible.

Call and messaging performance comparison between IMS and SIP networks

The IP Multimedia Subsystem (IMS) has been considered to be exclusive to big players of the telecommunication world. Session Initiation Protocol (SIP) has been standardized by IETF and solutions based on it have been in the market at least for a decade. It is also an essential part of the IMS, as it is the control protocol of IMS. Recent development of the Linux platform and the Open source IMS system has lead to a situation where the IMS is also an affordable solution for smaller telecommunication companies. The obvious question has been whether the level of performance with Open source IMS is really suitable for business usage. ETSI-TISPAN has unified IMS performance measurements by defining a common framework which to follow in measurements. The paper presents comparisons between IMS and SIP based networks in call and messaging performance. the Open IMS solution by the Fraunhover Focus Institute is compared with the OpenSIPS, an open source SIP server. The number of users in our measurements was chosen to be 100 000, a large enough number to be considered as a suitable number of users for small or moderate business usage needs. Our study shows that both of the systems are able to handle this many users and, in the case of OpenSIPS, with a clear margin. It was also discovered that both systems are reliable and are suitable for small and moderate business usage.

Power Consumption Analysis of the Always-Best-Connected User Equipment

Mobile Internet has rapidly evolved in the past years with an ever increasing number of novel technologies and services with a variety of access technologies. Indeed, todays mobile devices often support multiple communication technologies for accessing Internet services. For users the accessing of these data hungry services means that the mobile device has to be charged more often. Energy efficiency in mobile device communication has been considered to be out of users hands. The concept of Always Best Connected (ABC) allows a person to connect applications using the devices and access technologies that best suit to his or her needs, thereby combining the features of access technologies to provide an enhanced user experience for future Internet. This Always Best Connected scenario can make mobile device more energy efficient by using always the most energy efficient connection. Mobile communication networks and connected devices consume a small fraction of the global energy supply. However, meeting the rapidly increasing demand for more capacity in wireless broadband access will further increase the energy consumption. For example Cisco Visual Networking Index: Global Mobile Data Traffic Forecast 2010-2015 expects compound annual growth rate of 92 percent during 2010 to 2015 Operators are now facing both investing in denser and denser networks as well as increased energy cost. Current cellular systems based on Universal Mobile Telecommunications System (UMTS) and Long Term Evolution (LTE) is characterized by high spectrum efficiency, but low energy efficiency. In urban areas as well as in homes and offices alongside cellular networks IEEE 802.11 (WLAN in this papers context) networks are available. In this heterogeneous network environment the communication energy efficiency can make significant difference when considering how often the user has to recharge the mobile device. In this article we analyze energy efficiency of Always-Best-Connected solution. The application is used in measurements in a various real-life use-cases. The results are showing that algorithm can improve overall energy efficiency without compromising the user experience.

Challenges of the always-best-connected enablers for user equipment in Evolved Packet System

Mobile Internet has rapidly evolved in the past years with an ever increasing number of novel technologies and services with a variety of access technologies. Indeed, todays mobile devices often support multiple communication technologies for accessing Internet services. However, they all do not tap the full potential of these capabilities, as users often have to manually select each network, and only one network is used at a time. The concept of Always Best Connected (ABC) allows a person to connect applications using the devices and access technologies that best suit to his or her needs, thereby combining the features of access technologies to provide an enhanced user experience for future Internet. One of the key features for ABC in a heterogeneous network environment is the ability to make vertical handovers. These handovers are ones where the existing connection is changed from one technology to another. This handover has been considered to be complex and to generate a number of requirements.Over the resent years there have been techniques and standards to overcome the difficulties with vertical handovers. In this research the user equipment requirements of the most significant standards are examined and specification popularity in academic world and commercially is discussed. In addition, the performance of vertical handover with Android-based implementation is examined in real-life heterogeneous network environment. The presented standards are: Voice Call Continuity based on IP Multimedia Subsystem, Unlicensed Mobile Access, Media Independent Handover and The Third Generation Partnership Project Evolved Packet System. The research will show that existing mobile platforms such as Android environment is lacking some of the key requirements for vertical handover and current implementations cannot achieve seamless mobility by means that are currently defined by specifications.

Proxy Mobile IPv6-Based Seamless Handover

A prospective next generation wireless network is expected to integrate harmoniously into an IP-based core network. It is widely anticipated that IP-layer handover is a feasible solution to global mobility. However, the performance of IP-layer handover based on basic Mobile IP (MIP) cannot support real time services very well due to long handover delay. The Internet Engineering Task Force (IETF) Network-based Localized Mobility Management (NETLMM) working group developed a network-based localized mobility management protocol called Proxy Mobile IPv6 (PMIPv6) to reduce the handoff latency of MIPv6. Moreover, PMIPv6 provides the IP with the mobility to support User Equipments (UEs) without it being required to participate in any mobility-related signaling. This was one of the reasons why the 3rd Generation Partnership Project (3GPP) chose PMIPv6 as one of the mobility management protocols when defining the Evolved Packed System (EPS). One of the key features of the standard is its support for access system selection based on a combination of operator policies, user preference and access network conditions. Although Android, which is one of the most popular “mobile” operating system, is not officially supporting IPv6 nor PMIPv6, this paper analyzes the required challenges for IPv6 and PMIPv6 usage and handover performance with real-time services. The analysis and measurement results show that, with the modifications presented IPv6 and PMIPv6 may be supported and utilized for localized mobility management and seamless handovers. ...

Registration performance comparison between IP Multimedia Subsystem and Session Initiation Protocol networks

The IP Multimedia Subsystem (IMS) is an IP based service control framework architecture. It uses Session Initiation Protocol (SIP) to control its multimedia sessions. The IMS core can be considered as a collection of different functions that are linked with standard interfaces, forming an IMS core network. The IMS has layers for transport, the core itself, and for services and applications. The complexity of the IMS core is greater than within pure SIP based networks. To help to make comparisons between different IMS networks, the ETSI-TISPAN has unified the IMS performance measurements by defining a common framework which to follow. In this paper, the Open IMS solution by the Fraunhover Focus Institute is compared with the OpenSIPS, an open source SIP server used for users registrations to network. The number of users was chosen to be 100 000, a large enough number to be considered as a suitable number of users for small or moderate business usage needs. Our study shows that both of the systems are able to handle this many users and, in the case of OpenSIPS, with a clear margin. It was also discovered that both systems are reliable and are suitable for small and moderate business usage and further performance study trials

Context and location aware always-best-connected concept for heterogeneous network

Advances in wireless communication technologies are driving the evolution toward ever faster networks in terms of throughput and latency. User Equipments (UEs) have solid processing power, cameras and displays to produce and consume rich media and services. Their multi-standard interfaces allow them to utilize network-dependent services. However, tapping the full potential of these connected services call for the Always Best Connected (ABC) concept, allowing a person to connect to the services with the help of a personal mobile device and access technologies that are best suited to that persons needs. This paper introduces context and location aware elements in the decision making. The context relates to the services used: some of them, streaming and secure connections for example, can be sensitive to connection characteristics such as IP address change. Location awareness is introduced as a policy to assist in network selection. A reference implementation of the context and location aware ABC concept is introduced. Real-life use cases with real-life services in WiMAX, WLAN and UMTS environments are presented to back up the selected approach.