Mobile broadcasting has had a checkered history, with many of the grand plans for cellular TV services now dead in the water (at least outside China and Korea). Carriers found it hard to identify a profit model for a service that required dedicated new infrastructure, as platforms like the DVB-H standard or Qualcomm’s MediaFLO did. Indeed, Qualcomm shuttered MediaFLO, and sold the 700MHz unpaired spectrum in which it had run the network to AT&T ‘ which now looks set to have another go at this space. This time, however, it will use the LTE Broadcast system, which does not require a separate network, and the plan will be an element of a far broader strategy to leapfrog Verizon with multi-network, multiscreen services ‘ one that will harness all kinds of new technologies, from a new deal with community Wi-Fi player FON, to the massive small cell roll-out.
Verizon has been an early supporter of LTE Broadcast, and now AT&T has joined it in promising to support the technology, which is based on the 4G version of the MBMS standard. AT&T plans to use the 6MHz of 700MHz spectrum it bought from Qualcomm, which it has also tested for Supplemental Downlink, a way to use unpaired frequencies to add downlink capacity only in an otherwise paired network. The spectrum is national, and AT&T has an additional 6MHz in some of the most populous markets, such as New York, Boston, Philadelphia, Los Angeles and San Francisco.
The move comes after Verizon declared that it would bring its mobile NFC American Football rights to market in 2014, following a launch at January’s superbowl, using LTE Broadcast.
LTE Broadcast is a simple enough concept. The carrier dedicates at least one unicast video channel, plus a bit of network overhead, to create a single frequency network in a sub-channel of the LTE spectrum. With the full 6MHz, the system could support about six TV channels, while 12MHz would enable about 13. To use a single frequency network, the base stations select the same spectrum for the same TV channel, and send it in all directions.
They can arrange them dynamically so that, as one person starts watching TV, they are allocated the channel, and if someone else wants to watch the same program, their phone is instructed to tune to the same signal. As more people opt for a particular channel, these are voted into the multicast SFN. Alternatively, the carrier can arrange the channels, as Verizon plans to, so that all are devoted to the delivery of live events, with out-of-market and in-market paid services, and up to six camera angles on the same sports games.
This can be done with one, two or more base stations taking part in a transmission, or with the entire network, or with hundreds of femtocells joining in. In previous versions of MBMS some tuning logic was required in a separate chip, but this is now contained in device app processors such as those from Qualcomm, Sequans and others.
However, AT&T has no major live sports rights which demand that people watch content at the same time. Its other options are normal broadcast TV, software updates sent to phones, and broadcasting the most popular YouTube clips so when links are sent to phones, it retrieves these videos from onboard memory without going over the air. There are many other use cases – Verizon is said to have 100 prepared for its 2014 launch.
AT&T CEO Randall Stephenson said that AT&T’s focus was about architecting networks to deliver video and that will be where AT&T will spend the most capital over the next three years. This aims to relieve pressure on its wireless networks from over-the-top video providers – in particular YouTube and eventually Netflix, which right now is mostly watched at home over Wi-Fi. It is not even out of the question that AT&T could partner with pay-TV operators, to deliver content on the go, using this system alongside Wi-Fi offload.
The idea is to mature this technology over a three-year period, beginning in late 2014 ‘ AT&T is in less of a hurry than its arch-rival and is waiting for eMBMS components to find their way into the majority of smartphones and tablets.
In another announcement this week, AT&T has signed up to be the latest in a dozen-strong line-up of major carrier partners for community Wi-Fi organization FON. This was another idea that began simply enough – if you let other broadband customers use your home Wi-Fi for free, then you can also use theirs. While AT&T has invested heavily in its hotspots and in roaming deals round the globe, this latest move adds access to millions of FON international homespots.