-          Verizon has recently announced that they will be launching the Multimedia Broadcast Services over LTE In 2014.

-          AT&T Wireless will Build a LTE Broadcast Network tailor made for Video by 2014-15

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Mobile Data Traffic has been growing steadily since the advent of Smart Devices and this trend is gathering speed with major operators like Verizon and AT&T  announcing the launch of Multimedia Broadcast services over LTE.  Its estimated that today there are 50 Billion Connected Devices and ~15 Billion devices are Video enabled.

Figure 1 shows that Mobile Data consumption since 2011 has increased from 432,000 Terabytes per month to 6.6 Million TB per month in 2016, which an increase fifteen folds.

Figure 2 shows the traffic originated in the US market. It depicts the data downloads - especially from online video services and OTT players like Hulu, Netflix, YouTube are increasing.

The video content is increasingly being consumed over the air by people who are on the move or who are outside their homes. This is reflected in the popularity of services like VOD and interactive TV services. Research on user behavior indicates that the average time spent watching videos using a Smartphones or tablets is now approaching 5 hours in a week.   This increased appetite for video has paved the way for interesting business models to emerge from both service providers and content owners.

Why  e-MBMS?

The increase in data usage  and more specifically Video, is putting lot of pressure on the available bandwidth, especially where there are live events say like Olympics, World Cup Football etc., as many users simultaneously try to access similar content. The bandwidth requirements are doubled as user wish to enjoy HD quality video content.

Increasingly, technically savvy users are moving away from broadcast models when it comes to consuming digital content.   There is also a tendency to constantly switch from live streaming (broadcast) to on-demand services (multicast/unicast), resulting in a considerable debate on the best business case for delivering video.

Here is where benefits of Multimedia Broadcast Multicast Services (MBMS) come into play. The bandwidth consumption is not dependent on the number of subscribers who are watching the content at any instance, but is dependent on the no. of channels the operator is using to broadcast the content. LTE-broadcast would turn cell towers into the equivalent of mini-digital TV towers that could multicast video, audio and even data to multiple users simultaneously. The best part is that the LTE resources are allocated for e-MBMS by operators  only when needed or  when specifically  opted by Media content  providers like YouTube, Hulu etc.,  for certain premium customers to guarantee Quality of Service or QoS. 

How MBMS in LTE works?

Here is a simple illustration  of h.ow MBMS will help allocating the bandwidth in LTE networks. The existing carriers are flexibly allocated between Unicast or Broadcast.

New Logical, Transport and Physical channels are added in LTE [ to support e-MBMS. The Multicast Traffic Channel (MTCH) carries data corresponding to a certain MBMS service. The Multicast Control Channel (MCCH) provides necessary control information to receive MBMS services, including sub frame allocation and Modulation Coding Scheme (MCS).

On the UE side, there is a need to support the new e-MBMS channels and also some specific changes in Middle ware are also happening. DASH protocols (Dynamic Adaptive Streaming over HTTP) are increasingly being used instead of traditional RTP. DASH allows seamless transitions between unicast and broadcast based on coverage and popularity of content.

Advantages of e-MBMS over other Broadcast Technologies

There are few other Technologies related to Video Broadcasting such as DVB-H, DVB-T2, ATSC M/H which are widely used in Digital TV broadcasting.

e-MBMS has the following distinct advantages over the existing technologies.

1. All IP network- enables  unicast and broadcast service with high capacity, high bandwidth and high scalability
2. Larger Device  and Operator Support  -eMBMS is based on the LTE radio specifications and major chipset vendors on device side  and  major Operators like Verizon and AT&T have committed to support it from the beginning of 2013. This brings economies of Scale and enables e-MBMS reach larger masses.
3. Reuse of LTE Network resource s- e-MBMS does not need special infrastructure and uses the existing LTE resources.

Clearly from the above, compared to other video broadcast systems, with e-MBMS in LTE the operator has the flexibility to dimension unicast and broadcast with minimum changes to their LTE infrastructure. Identifying the right mix of services to keep subscribers interested is the real challenge. Operators clearly cannot impose a full-fledged broadcast model. That is why e-MBMS is a good option for delivering near-live, prerecorded and pre-published content, especially for multicasting content during off-peak hours and storing them in the terminal.

At Sasken, we are closely working with LTE and the latest technology features of LTE including e-MBMS. We have been closely working with Semiconductors partners, Handset and Network OEM's, Operators & ISV’s, in development, Interoperability Testing and commercial launch of the LTE based products and services.

Authored by Ravi TVS