Thanks to the guys at Fraunhofer FOKUS in Berlin, IMS has moved from theory to at least a bit of practice for me as I reported in THIS BLOG ENTRY. As a little souvenir, I got the (Wireshark) pcap trace for an IMS voice call from many different interfaces including interactions between the IMS core … Continue reading An IMS Wireshark Trace
I've been speculating recently how voice calls could work in next generation 3GPP LTE networks. The politically and technically foreseen way is IMS, the IP Multimedia Subsystem, and a service platform running on top of IMS such as the IMS Centralized Services (ICS). ICS is quite promising as it includes a solution to bring GSM only handsets without any IMS extensions into an overall voice solution and can hand-over voice calls from LTE to GSM when leaving the coverage area. The major drawback of ICS is its complexity and its anyone's guess when we will see this in mobile devices for the general public.
In the meantime, there has been some support in 3GPP to investigate a different solution: How to extend the current circuit switched voice service of GSM to LTE. In 3GPP a number of companies started writing some proposals, which were gathered in 3GPP TR 23.879. In this paper, the main proposal is to connect the Media Gateway part of the Circuit Switched Mobile Switching Center (MSC) to the packet core and give the the MSC Server direct access to the Mobility Management (MME) Entity of the Access Gateway to the LTE Radio network.
Interesting to see which 3GPP Release 8 work items around the IP Multimedia Subsystem (IMS) are bearing fruit these days. While in Release 7, the hot application specifications for IMS services were Multi Media Telephony (MMTel) and device centric Voice Call Continuity (VCC), work in Release 8 seems to have to have shifted towards IMS … Continue reading IMS Centralized Services (ICS)
In the fixed line world, the basic Session Initiation Protocol (SIP) has become quite popular for offering voice telephony service. Lots of companies such as Vonage, Siptel and DSL providers are making use of it today. So why are we not using SIP in 3.5G and 4G networks as well? I guess there are both … Continue reading How To Extend SIP For Mobile Networks
News from the ITU (International Telecommunication Union) on 4G, aka IMT-Advanced: In a recent meeting it was decided that technology has now moved sufficiently beyond enhanced 3G systems (such as UMTS HSPA, WiMAX, CDMA1xEvDo also called ‘enhanced IMT-2000 systems’ in ITU terms) that the selection process of suitable technologies for 4G can now begin. In … Continue reading IMT-Advanced (4G) Submission and Evaluation Process
Recently I spoke to a sales engineer of Kathrein, a prominent German antenna maker that develops and produces all sorts of antenna equipment from TV antennas to sophisticated cellular network antennas. I can still remember how simple antennas were 10 years ago when GSM was first deployed: In many places simple dipol antennas were used … Continue reading Antenna Stuff
I just saw Nokia’s announcement of the 6300i and had to take a closer look. While I am more of a fan of their Nseries devices, the announcement nevertheless caught my eye since the 6300i includes WLAN for browsing and VoIP. While Nokia’s website doesn’t (yet) confirm that VoIP equals a SIP client (and not … Continue reading Nokia 6300i: WLAN and VoIP move to Mid-Range Phones
After having had the pleasure of hosting the Carnival of the Mobilists last week, it has moved on this week to Tarek Ghazali in Egypt and his Symbiano-Tek blog. As always great insight and many entries which require some more contemplation. Here’s the link so go and check it out!
In my previous IMS post I’ve taken a look at the difference between SIP telephony networks and the IP Multimedia Subsystem (IMS). With that list it is quite obvious that the IMS is a centralized session management system that gives lots of control to the network operator and makes it quite difficult for third parties … Continue reading IMS Applications
While work is ongoing on 3GPP LTE (Long Term Evolution) and SAE (System Architecture Evolution), current 3G networks continue to be enhanced as well. Since the 3G air interface is in the process continues to evolve with HSPA (High Speed Packet Access) it was felt in the standards groups that the 3G core network should … Continue reading Direct Tunnel – GPRS Core Network Streamlining