When discussing 5G you should treat the word “ubiquitous” as a red flag.
I often hear it used by policymakers in Brussels, DC or London. It’s regularly spoken by tech vendors, especially those concerned with “monetisation” of 5G, or business models based on network slicing or QoS.
Application and IoT vendors, in areas such as AR/VR, gaming or connected vehicles, often assume it implicitly.
It is not, however, a term often used by people on the radio side of the industry. They understand that even basic coverage of 5G is unlikely to get close to ubiquity. And they definitely know that true high-performance 5G, capable of supporting gigabit-speed, millisecond-latency, dense-user slicing hype won’t be ubiquitous. It will be patchy and often need dedicated engineering efforts.
While I’ve often discussed indoor coverage issues for 5G, recently I was on a webinar about another trouble spot: trains. Think of a busy train as a moving small town of 1,000 people, many of whom are using phones and laptops, and you get a sense of the issues.
Especially over long distances, many will be watching videos, playing games, doing Zoom/Teams meetings, live-streaming their journey and much more. Plus there are critical train operational needs for safety control and telemetry, which take priority over passengers’ data.
Investment horizons for rail can be 20-30 years, so we may have to think about 6G, 7G and even 8G applications, not just 5G.
Today, getting 1 Gbps directly to a terminal on the roof of a moving train is possible, but complex and expensive. That can feed Wi-Fi for laptops and other devices. But that’s the equivalent of a single home’s good quality broadband, split between 100s of data-hungry people. Uplink is much less, usually.
There is also 4G/5G connectivity through the windows direct to smartphones, but that varies along the track (especially in cuttings, tunnels and remote areas) and gets attenuated through the body of the train. Forget mmWave for this.
Dedicated trackside cell towers are economically challenging, as they might only be active at full power for a minute an hour when a train passes (or two trains in opposite directions).
Various neutral host models are promising, but mostly on the busiest sections of tracks, and even then coverage/capacity will be limited in scale. Governments are keen to promote train connectivity, but they cannot change physics.
In other words, you can forget about millisecond-latency games or AR/metaverse business meetings while you zip around the country.
This is problematic. It means 5G “super-services” either need to be confined to specific locations, or else they will need mechanisms for fallback to lower-grade (or zero) options. The MNO and its BSS software will need to apologise to, or compensate, people who can’t get their promised QoS or URLLC everywhere. Its SLAs will need large exception clauses (“do not use on trains”). They may need insurance.
“Semi-ubiquitous” is hard to monetise.