Multimedia Broadcast/Multicast Service (MBMS) is a concept that has been lingering in the mobile telecom world for close to two decades now. The basic idea is that network resources are used to send the same multimedia content to everyone (broadcast) or to a group of subscribers (multicast) rather than sending content to individual subscribers (unicast) which is how we typically consume media today. Think YouTube and Spotify and you’ll see what I mean. The chance is minimal that someone in the same cell as you is watching or listening to the same thing as you at that very moment. And even if someone did, the content would be streamed to you individually.
If you are old enough to remember the big 3G hype around the millennium shift, you may have encountered MBMS already. In short, and a bit simplified perhaps, the idea was that telecom operators would also become media/content distributors and the 3G networks would be used for broadcasting/multicasting of e.g. TV programs, movies, sports events and music.
Not only would this require some re-engineering of the actual networks – the technical implementation of MBMS – but also have implications in terms of roles and business models. For a number of reasons this did not happen, and business analysts probably have solid explanations as to why it didn’t. But as we all know, the media/content/distribution ecosystem has changed dramatically with the emergence of new companies, technologies, business models and changed human behavior. When did you for instance last tell someone that you wanted to watch a good movie on TV that starts 9.30 pm? And when – with the notable exception of important sport events – are people actually watching the same content at the same time? We live in the unicast age, don’t we?
From a technical point of view, making a network MBMS-capable requires some additional nodes (or functions) in the core and service networks: a Broadcast Multicast Service Centre (BM-SC) which is where media originates and an MBMS Gateway (MBMS GW) to insert the media into MBMS Bearers which are the “bit pipes” provided by the 3G or 4G network for distributing media. Obviously we also need radio resources in the form of transport channels and physical channels that can be received and properly decoded by multiple viewers and listeners.
So, why am I writing about an idea that has been lying more or less dormant for decades? Well, it turns out that there are new important use cases for MBMS in 4G and 5G, none of which were probably even discussed when MBMS was originally conceived in the midst of the 3G hype.
Mission Critical Communication, aka PPDR (Public Protection and Disaster Relief) i.e. communication systems used by police, fire fighters and emergency personnel are today typically based on standards like TETRA and P25. TETRA (Terrestrial Trunked Radio) is robust, reliable and a lot of other things that we would like a mission critical communications system to be. But it’s basically a 2G system which means that data bit rates for sending e.g. building plans to fire fighters are low, which is why the mission critical communications community is looking at and planning for a migration to systems based on LTE and IMS. And here is where MBMS comes into the picture. For transmitting audio, video and data in any combination to police officers or fire fighters at an emergency scene, using unicast would simply be an unacceptable waste of precious radio resources. Hence, multicast or broadcast is the only way to go, and a requirement for mission critical communication.
Another use case is IoT, or at least IoT-related. The connected “things” will have very different communication patterns, depending on if they are e.g. electricity meters, surveillance cameras or refrigerators. But we can easily imagine that occasionally someone – the electricity company or the white goods manufacturer – wants to update the software in its connected things. Imagine updating thousands, millions, billions or a zillion “things” by sending new software to them one-by-one… For this scenario, using multicast and MBMS sounds like the right way to do things.
Conclusion: Will the MBMS Breakthrough Finally Come in 5G?
So, after a slow start it looks like MBMS could come alive for real in the 4G-evolving-into-5G-era, although perhaps not for the original reasons and use cases. But on the other hand, the fundamental idea, that sometimes it is better to send the same information to multiple users, is as valid today as it was 20 years ago.
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Until next time,
The Apis IP-Solutions Team