Live Streaming Over Cellular: Protocols, Challenges, and Innovations

Live Streaming Over Cellular: Protocols, Challenges, and Innovations

Live streaming over cellular networks has become a cornerstone in various industries, including broadcast, mobile surveillance, and teleoperations.  As we approach the end of 2023, several streaming protocols dominate the landscape, providing different advantages and challenges. Additionally, proprietary protocols like RASCOW2 from Soliton are gaining attention for their unique capabilities in addressing the unpredictability of public networks and delivering ultra-low latency especially over the unpredictable nature of some wireless networks such as 4G.

  1. Commonly Used Video Streaming Protocols: -
  • HLS (HTTP Live Streaming): Widely employed for end-user delivery due to its adaptive streaming capabilities. HLS is compatible with most devices and browsers including smart TVs, set-top boxes.
  • MPEG-DASH (Dynamic Adaptive Streaming over HTTP): Ideal for adaptive bitrate streaming, providing a seamless user experience. Similar to HLS, MPEG-DASH supports adaptive-bitrate streaming that optimizes bit rate depending on the available bandwidth for each user.
  • RTMP (Real-Time Messaging Protocol): Historically crucial for live streaming and interactive applications. For live streaming events, it is often used as the streaming IP protocol of choice from the video encoder to the streaming platform before it is delivered to the end user through the common HLS protocol. It assumes a good and stable network connection such as fiber and is not so optimized for cellular.
  • WebRTC (Web Real-Time Communication): Facilitates real-time communication directly between web servers and browsers. WebRTC is a relatively low-latency streaming protocol that empowers peer-to-peer streaming (P2P) and is adopted by popular messaging apps such as WhatsApp, Google Meet, Discord, and Facebook Messenger.

WebRTC continues to be a game-changer in the live streaming arena. This open-source protocol facilitates real-time communication directly between web browsers, eliminating the need for additional plugins or software. As we move forward, leveraging WebRTC can lead to more accessible and seamless live streaming experiences for end-users

Soliton has adopted WebRTC as part of its ultra low latency architecture for video delivery to the end user from its transmitters. WebRTC is normally uses an H.264 codec, Soliton has taken this a step further by using H.265 and creating a real-time embedded viewer that is capable of showing the native H.265 WebRTC stream. This is the first of its kind as far as we are aware, and show cases innovation at its best!

  • SRT (Secure Reliable Transport): Ensures secure and reliable video contribution over unpredictable networks but if bandwidth drops below a certain threshold then it will stop often making it unsuitable over cellular connectivity where contention or lack of bandwidth is an issue.
  • RASCOW2 by Soliton: Specifically designed for video contribution (ingest), leveraging H.265 compression for high-quality transmission from cameras to central locations. 
  1. Challenges and Innovations: -
  • Challenge: Inconsistent cellular network conditions

Innovation: Protocols like SRT and RASCOW2 address unpredictability, ensuring reliability and low latency. However unlike RASCOW2, when bandwidth drops, often a sudden fall, SRT does not cope and takes time to recover only when bandwidth is restored,  where as RASCOW2 will drop framerate for a fraction of second before recovering quickly.

  • Soliton's Zao SDK: software library

Innovation: Soliton's Zao SDK as a new software library that introduces advancements in mobile live streaming with ultra low latency, enhancing the overall streaming experience. As it can be installed on a customers own hardware as a software, this lends itself ideally to teleoperations such as remote driving of vehicles and Unmanned Ground Vehicles (UGVs), control of BVLOS drones,  and remote control of machinery such as cranes, where almost real time operation over cellular networks is crucial for safety reasons.

  1. Future Trends: -
  • Edge Computing (MEC) for Reduced Latency:

Reducing latency is a constant pursuit in live streaming. Edge computing, by processing data closer to the source, significantly decreases the time it takes for data to travel, resulting in lower latency. This innovation is crucial for applications like teleoperations, where split-second decisions are paramount.

  • AV1 Video Codec for Enhanced Compression:

The AV1 video codec is gaining traction for its ability to deliver high-quality video at lower bitrates. As bandwidth efficiency becomes increasingly crucial, AV1 can be a game-changer and a potential competitor to H.265. The advantages claim the fact with AV1 there are no royalty payments. But more often than not, with H.265 the royalty burden is with the manufacturers not the end user and H.265 is more widely adopted.

  • 5G Networks:

The advent of 5G networks enables higher data speeds and lower latency connections for seamless live streaming experiences, but the 5G rollout has been slower than everyone expected. This delay is attributed to the necessary infrastructure updates and the installation of additional antennas, required due to the higher frequency and lower distance that 5G can propagate. The claim of extra reliability over 5G, especially when covering long distances—such as live streaming from drones, remains unproven. However, ongoing development includes 5G antennas that can track phone devices, even at altitude, enabling BVLOS drones to use SIM cards for live streaming and remote control.

  • What about 6G?

Well 5G is yet to adopted effectively… and the 6G landscape is in its early stages, with ongoing research and development. Current focus includes envisioning technologies beyond 5G, aiming for immersive communication and omnipresent connectivity. Future prospects include smart home networks, automated cars, and advancements in materials for lossless communications, setting the stage for a transformative era in mobile communication beyond 2030.

  • Satellite as a Redundancy:

Starlink has been quickly adopted worldwide as a commoditized satcom provider, and is ideally placed for cost, and offers relatively low latency given its low orbit. Satellite connections act as a backup in areas with limited cellular coverage, offering a reliable alternative but is obviously far more bulky than a sim card!

The amalgamation of established streaming protocols such as SRT, and emerging technologies like RASCOW2 by Soliton, showcases the evolving nature of live streaming over wireless connectivity that includes cellular and satellite, as well as Wi-Fi and other private RF links. As the industry progresses, innovations will continue to address challenges, providing businesses and audiences with higher quality, lower latencies, and more reliable live streaming experiences whether it is for broadcast, surveillance or teleoperations.

In the coming year, these protocols and innovations are set to shape the future of live streaming, creating new possibilities and challenges. At Soliton Systems, we're committed to staying at the forefront of these advancements to provide you with cutting-edge solutions for broadcast, mobile surveillance, and teleoperations.

Mark Andrews

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