Today’s mobile phone networks use various frequency bands below 3 Gigahertz (GHz) which are best for providing coverage over large areas. However, the amount of resource, or bandwidth, is limited with typical allocations to a mobile operator in each of these bands being less than 20 Megahertz (MHz). In order to find much greater bandwidth, the industry is assessing a number of candidate bands above 24GHz which have been identified by the World Radio Congress. It is at these frequencies that the greatest bandwidth can be found and where 5G will deliver the highest data rates.
One of the bands currently being considered is at a frequency of 70 GHz. At this frequency, antennas can be built at the transmitter and the receiver, enabling the radio signal to be steered, or beam-formed, with a high level of precision. In addition, objects near to a receiver can be used to ‘reflect’ a second beam towards the receiver using a process called Multiple Input Multiple Output or MIMO. The combination of both features helps to increase range, performance and capacity.
There are significant engineering challenges associated with using these frequency bands. The radio signal is less capable of penetrating obstructions and the radio beams must be able to track the location of a device that is moving quickly. As a result, researchers are working to address these challenges as part of ongoing to work to determine how best to deploy and operate 5G networks.
Working with Huawei we have recently completed a 5G field test in Newbury that demonstrates the capabilities of a trial system operating at 70 GHz. In our tests we have been able to reach data rates of over 20 Gigabits per second (Gbps) and support multiple users that receive 10 Gbps each.
This means that using the technology it’s possible to deliver an extremely high level of performance for an individual link, such as backhauling data between two locations, or supporting a large number of connections in small areas such as stadia or train stations.
These tests contribute to the ongoing research into spectrum above 24 GHz for 5G enhanced mobile broadband. They will also contribute to research activities that will lead to 5G spectrum harmonisation at the next World Radio Congress in 2019.
Commenting on the trial, Johan Wibergh, Vodafone’s Group Chief Technology Officer, said: “This field test in an outdoor environment is a significant step forward in validating the performance of 5G in high frequency bands. It has improved our understanding of the capabilities and opportunities that the technology offers.”
Eric Xu, Rotating CEO of Huawei, said: “5G will introduce full spectrum access to support AR, VR, Smart Automobile and other unknown new services. The joint trial of 5G mmWave connectivity in a real world radio propagation environment and co-existence of different radio links is encouraging. I highly value the cooperation with Vodafone, and believe we will achieve more progress in 5G, together with Vodafone and other industry partners.”
David Lister leads Vodafone Group's Future Technology Team in its Research & Development Department. His work spans various disruptive technologies including 5G. He has worked for Vodafone Group since 1992.