Cellular Bonding for Live Event Streaming: The State of The Art

When Will 5G Be a Thing?

None of the executives we spoke with expect 5G to become relevant anytime soon. Akin, from Mushroom Networks, predicts that 5G is at least several years away, as mobile companies try to maximize the profitability of their investments in 4G technology.

Hildeman from Streambox believes that LTE Advanced, which has been deployed by Verizon in more than 450 U.S. cities, could have a more immediate impact. Interestingly, LTE Advanced, which uses carrier aggregation to utilize multiple LTE channels at once, is a form of a bonded solution. Hildeman also notes that companies like Google and Comcast are deploying large networks of Wi-Fi hotspots, and that bonding devices should also benefit from incorporating these into the aggregate signal.

Finally, Teradek’s Landman points out that all providers in the space are agnostic as to the cell signal, since the key technology is how efficiently they can mux them together. So supporting new technologies should occur soon after they become relevant.

Choosing a Vendor

All of this has been interesting (I hope), but you’ve probably read this article to assist with an upcoming buying decision. So here is some specific advice for that. Step 1 is always to plot out how you’ll be using cellular bonding, which can range from simple, stream-to-Facebook-Live applications, to point-to-point video transmissions to decoders in your studio, to more complicated hybrid schemas that involve encoders, decoders, and the cloud.

In particular, if you have existing encoders that you need to use, you’ll want a transport-only solution. Recognize, however, that integrated encoding/bonding solutions may provide a more-functional solution overall. That’s because within an integrated solution, the encoder can adjust the data rate of the encoded video upward or downward to reflect the available bandwidth, improving quality when bandwidth is plentiful, but preventing dropped frames and stoppages when bandwidth drops. If you’re streaming from a notebook running vMix into a modem-only solution, there’s no back channel for adjusting the encoded bitrate if bandwidth drops, so you risk stoppages—or you’ll have to stream at a less-aggressive data rate to avoid them.

Then assess product requirements like miniaturization or ruggedization to identify which families of solutions can meet your needs. From there, ask the following questions and take these steps before buying a cellular bonding solution, whether from one of the vendors included in this discussion, or any other.

Ask Around

Recognize that there are multiple factors that impact throughput beyond the speed of the underlying cellular modems. Specifically, the underlying technologies that differentiate products from these companies include how efficiently they can bond together the signals, and how fully they can utilize the bonded signal. All companies also offer some form of error correction to maintain a robust signal when packets are lost. As you’ve learned, cellular bonding systems use different codecs, including H.264, H.265, and Streambox’s ACT-L3 codec.

All of these factors impact the bandwidth necessary to transmit a sufficiently high-quality video signal, and they impact each device’s ability to maintain that bandwidth. The best way to figure out how a particular device will perform in your area is to ask producers who are already using it. While you’re at it, you should ask how many modems they’re using, and from which provider.

• What’s the Minimum Functional Bitrate?

While it’s probably not relevant in most regions in the U.S., minimum bitrate becomes critical in many other countries. If you’ll be operating outside of the U.S., this is one number you need to know.

• What’s the Available Cloud Functionality?

When you choose a cellular bonding modem, you’ll likely also be buying into the cloud solution offered by that company. So understand what you’ll need from the cloud before buying the hardware, and understand what it will cost, particularly if you’ll use the cloud service to transcode from HEVC or ACT-L3 to a format your target CDN or social media service can accept.

By this point, most cloud services should be able to remotely update, configure, and control their encoders, provide previews of all streams, route streams to multiple points (including social media services), and archive the streams. If your usage will be primarily local or regional, most cloud services should work well. However, if you’ll be routing signals around the globe, you should understand whether the cloud service has the infrastructure and protocols to efficiently support this.

Take these steps, and follow the guidelines provided within this article, and you should be able to configure, acquire, and use a functional system that reliably gets your signal up to the cloud, and to multiple output points from there.