![uplink downlink uplink downlink](https://www.mdpi.com/sensors/sensors-20-03285/article_deploy/html/images/sensors-20-03285-g001.png)
In most cases, the chances of interference between networks are small and nearby users can probably be well separated in frequency. They mostly operate over shorter ranges with lower power than public networks and will often be providing mainly indoor coverage in private buildings. At the moment there is plenty of spectrum available in the 3.8-4.2GHz band and private networks are scattered across the country. So why not just change the timeslot configuration to match the application? In principle this is possible in a private network using an Ofcom Shared Access Licence. Time will tell whether this will also be the case in public networks. This suggests that traffic in private 5G networks may be less asymmetric than in previous networks and may even swing the other way, with uplink dominating. The exceptions are those projects involving AR and VR - such as the 5GEM and 5G Encode projects - which also have heavy downlink loads. These applications range from live filming of sports in the Live + Wild and Connected Cowes projects through monitoring of industrial processes,Įnsuring safety of passengers on public transport, finding parking spaces and monitoring road traffic in our wide range of testbeds in the West Midlands (WM5G) to scanning of crops in the 5G RuralDorset and MONeH projects. Ironically, a majority of our trials in the DCMS 5G programme seem to have use cases that are actually uplink-heavy, typically involving some form of video capture. In practice, a similar approach is adopted globally.Īt first sight, this makes much more efficient use of the spectrum if it matches the downlink dominated traffic demand. For this reason, Ofcom effectively mandates that all public 5G networks in UK shall use a 3:1 ratio of timeslots between downlink and uplink and be synchronised in time. This leads to the likelihood that base stations on different but adjacent channels may interfere with each other if one is transmitting while the other is receiving. The path loss between nearby base stations can be very small, as they may be both in high locations within sight of each other. Unfortunately, there are some limitations to that flexibility. This offers some flexibility in the allocation of resources between the two. In TDD a single block of spectrum is time-shared between uplink and downlink. Along with 5G came a new technology, Time Division Duplex (TDD). This leads to a conclusion that, in FDD networks, some of the uplink spectrum is being wasted. Until 5G, almost all networks used a technology known as Frequency Division Duplex (FDD), in which equal chunks of radio spectrum are used for uplink and downlink. In video, now the major load on public networks, most of us watch far more than we originate. Given the one-to-many nature of email, it will always be downlink heavy. The average user downloads much more data than they upload. Historically, the driving force in public mobile networks for speed and capacity has been the downlink. Digital Connectivity Infrastructure Accelerator Project.