IMS Core Network Research Articles

Using 4G Elements to Provide Secure Services Network Access

The entire telecommunications and services world has focused its attention on the newest 3GPP architecture, 4G. Proposing high speed data transfer, all flat-IP network for the core systems and stronger authentication and AAA methods, this architecture seems to be the answer for the mobile networks of the future. Another architecture, described by 3GPP as well, but based on IETF standards is the IMS architecture. This is focused on mobile services, mainly VoIP, but also presence, push-to-talk, location and multimedia and broadcast services. The IMS core network has its own security mechanisms, which are constantly tested and improved. Looking in the perspective, the user equipment, specially the one found in roaming has to do a lot of signaling in order to authenticate to both networks and use the services available for it in a secure manner. From the provider’s point of view, the issue is even more complicated, because it has to secure its network, securely interoperate with other networks, be able to obtain granular charging information and also provide lawful interception capabilities for the government institutions. This paper reviews the authentication security architecture available in 3GPP for providing secure access to application services, with emphasis on the interaction of 4G and IMS components, being the first step in a larger 4GIMS interaction study with regards to security.

Quality of experience (QoE) driven adaptation scheme for voice/video over IP

Network quality of service (NQoS) of IP networks is unpredictable and impacts the quality of networked multimedia services. Adaptive voice and video schemes are therefore vital for the provision of voice over IP (VoIP) services for optimised quality of experience (QoE). Traditional adaptation schemes based on NQoS do not take perceived quality into consideration even though the user is the best judge of quality. Additionally, uncertainties inherent in NQoS parameter measurements make the design of adaptation schemes difficult and their performance suboptimal. This paper presents a QoE-driven adaptation scheme for voice and video over IP to solve the optimisation problem to provide optimal QoE for networked voice and video applications. The adaptive VoIP architecture was implemented and tested both in NS2 and in an Open IMS Core network to allow extensive simulation and test-bed evaluation. Results show that the scheme was optimally responsive to available network bandwidth and congestion for both voice and video and optimised delivered QoE for different network conditions, and is friendly to TCP traffic.

Presence Network Agent: A Simple Way to Improve the Presence Service

The article examines a possible way of improving the performance of the presence service within IMS networks without modifying the presence and group management enabler. This can be achieved by means of a presence network agent (PNA). The PNA has been defined by 3GPP; it is a new logic entity within the IMS core network that is able to publish the presence information on behalf of the presentity user agent. The PNA improves performance because it reduces the presence signaling load within the radio access network without downgrading the freshness and richness of the presence information. The article's goal is to provide the reader with useful information about the PNA and our experience with PNA implementation and deployment. We first describe the PNA concept as defined by 3GPP, highlighting the open issues still present in the standardization and the possible optimizations, subsequently we present an actual implementation of a PNA handling busy/idle states for IMS calls.

Aspects of network security for VoIP solutions using IMS core network and Wi-Fi access

Aspects of network security for VoIP solutions using IMS core network and Wi-Fi access

Aspects of network security for VoIP solutions using IMS core network and Wi-Fi access

A network providing Voice over Internet Protocol (VoIP) service requires many network elements. Each network element may have its own set of security capabilities, but not all security capabilities...