“What on earth happened to LTE-Broadcast?” Taking a look back through our archive, we see it was a year almost to the day since the term last appeared in an issue of our sister service, Faultline Online Reporter (which focuses on digital video). So why has talk of using the technology for consumer multicast video applications all but vanished after such promising progress throughout 2016 and 2017?
Our other sister service, Wireless Watch, has some more recent references (six months ago), but these are to specialized industrial and vehicular applications (see below), not mainstream use cases such as live sports services, which were the focus of the early trials of LTE-B. The analysts at Faultline addressed the issue recently, as follows:
It’s perhaps easiest to point the blame at 5G but in truth there are a number of contributing factors. We have prodded the LTE-B Alliance for an update, but the fact the most recent blog post is dated January 2017 implies the Alliance won’t be hanging around for much longer.
Ironically, the starting point for our coverage back in October 2017 was the public frustration of Matt Stagg, the head of mobile video and content at UK telco EE, a founding member of the LTE-Broadcast Alliance. Stagg was annoyed that no operators had gone live with the technology yet, and basically said its association with video streaming – particularly live sports – was hindering progress rather than helping it. He claimed high profile trials were overshadowing the technology’s broader scope, for example for expanding into IoT use cases, or using LTE-B for emergency or rescue situations.
Other than Australian telco Telstra, another founding member of the LTE-B Alliance, there isn’t a single other Tier 1 operator using the technology for live sports – so Stagg was clearly getting his excuses in early for a network technology which has divided opinions unlike any other. Reliance Jio in India is a special case, adopting the technology but without having any real involvement with the Alliance.
Another barrier has been the apparent lack of middleware required to connect the chipset with the LTE-B software, most notably in iPhones. Qualcomm’s Snapdragon processors support the technology but Jio said these were too expensive and it’s likely this deterred other operators too. SoftBank was another major name trialing LTE-B, using a video streaming and encode server from AT&T-owned Quickplay Media for the BBTV Next service. Radio silence has since come over the operator, going on two years.
LTE-B (also known as LTE Multicast or eMBMS) allows a single piece of content or data to be distributed to multiple users simultaneously by using part of a base station’s spectrum in a single frequency network broadcast, and can be used to improve the spectral efficiency and user experience in applications like mobile TV, over-the-air updates, interactive advertising and others.
Our expectations were for LTE-B to be a technology invisible from the consumer view, used by operators to lower video delivery costs while enabling mobile subscribers to get zero-rated content. But even here adoption has fallen well short of expectations.
The last word from the LTE-B Alliance linked to a post from Telstra’s outgoing head of networks, Mike Wright, talking about the introduction of the multicast operation-on-demand (MooD) feature. “Cells in the network only need to configure for LTE-B when there are multiple users watching the same content. This combined with the Service Continuity feature allows mobile users to move around the network seamlessly between cells configured for LTE-B and those which are not.”
Could these be the Alliance’s final words? Personally, not a single mention of progress has been dropped in during conversations at trade shows and conferences, nor has an inkling of progress been pushed across the wires.
Perhaps LTE-B will not die, but become one of those technologies whose usefulness ends up being in very different areas from those originally envisaged. In April, for instance, Nokia and Japanese operator KDDI claimed the first application of LTE-B to vehicle-to-vehicle (V2V) communications, as a step towards autonomous driving. The test was carried out to evaluate whether broadcasts to all cars within proximity would work as intended for V2V applications.
The use of LTE-B multicast (one-to-many) rather than unicast (one-to-one) for low latency V2V connectivity could be a more efficient way of distributing information from sensor networks to all vehicles in the vicinity, minimizing bandwidth consumption. And it points to the way that LTE-B may gain more traction in telematics applications than distributing video as originally conceived. It allows specification of hotspots, which could be stadiums receiving video relating to an event taking place inside, but could equally well be, as in the V2V case, clusters of sensors transmitting simultaneously to multiple vehicles nearby.
Nokia’s MEC (Multi-access Edge Computing) platform provided the core of the Vehicle-to-Network-to-Vehicle (V2N2V) communication trial, keeping constant communication with the cars, forwarding location, speed and directional data to roadside sensors. Then, in an emergency, a driver, or eventually a vehicle itself in autonomous mode, could inform other vehicles for immediate action to be taken.
A second use case was to investigate automated in-vehicle navigation through so-called Network Real-Time Kinematic. This also addresses safety in autonomous or even assisted driving, exploiting existing satellite based and other geo-location systems to distribute real time positioning information down to cm level accuracy. Therefore, very low latency is critical for otherwise the information would be out of date and therefore by definition not high precision. The objective here was to investigate potential for cooperative driving rather than individual vehicle decision making, introducing collision prevention as a first layer of safety with the sensor base systems then kicking in for collision avoidance if this fails.
AN important angle to trials like these is the mobile industry’s desire to use 4G for as many new use cases as possible while the business model is being clearly defined, and to postpone the need to invest in new 5G technology. By demonstrating the efficacy of 4G for an important aspect of autonomous driving Nokia could be helping to prolong the life of 4G, even in an application which has been one of the leading examples of a use case that requires 5G.