Opening up UK 5G networks with millimetre wave

15th October 2020 by Mark Barrett

A radical programme is opening up new ways to roll out 5G mobile networks in the UK, all the way from the radio front end through to the core network.

The Open RAN (O-RAN) Alliance is an initiative to open up the interfaces between the various parts of the mobile networks in the radio access network (RAN).

Typically, at the moment those interfaces between key sub-systems for example the RAN (Radio) and Core networks, are closed so an operator has to buy a complete system from one vendor, but O-RAN disaggregates this. It disrupts the radio space or core switching space or software space for 5G in the same way that open standards, which underpin the PC and Ethernet data communications, opened up the Internet. O-RAN aims to open up 5G mobile networks to new entrants and operators that want to disrupt 5G with new equipment and service offerings.

For us at Blu Wireless, the opportunity for operators is the ability to connect the O-RAN systems to the backhaul that is of interest, to connect the front end 5G NR (new radio) small cells to the core network.

We recently won a project supported by the UK government to extend the connections of 5G NR small cells using millimetre wave connections across Liverpool that shows how this can be used.

One important aspect of O-RAN is the split, the different levels that are used to define the interfaces between communication layers of the system, from the radio interface (PHY Layer) up to application (Layer 7). These have been defined by the O-RAN Alliance in order to enable trade-offs to be made between system decomposition and interface performance between sub-systems – thus allowing equipment and software from multiple developers to interoperate. An important trade-off for the choice of split relates to end to end latency for each connection. This can vary from less than 200 microsecond for a PHY layer split (Split 7.2 as typically used for Front Haul) up to 2 msec for a MAC layer split (as typically used in Back Haul).

The O-RAN alliance has already created 31 specifications, with well over 37 demonstrations of the technology and more than 1 000 000 lines of code released in partnership with the Linux Foundation.

With this approach, one end connects to a the 5G NR small cell using the split 2 interface and connects over a millimetre wireless link to a fibre Point of Presence to access the core network.

The advantage of our approach is we operate across the full license exempt band 57-71 GHz , and including the 64 to 71GHz which is outside the oxygen absorption at 60 GHz and is therefore well suited for long range (1 km or more) wireless links. Our product is implemented within, a small (300mm & 4kg), low power (50W) form factor unit, with integrated low-profile phased array antenna that can easily be mounted on a lamp post. We are in discussion with several mobile operators and private network customers in the UK, France and USA with regard to deployment our mmWave equipment for mobile backhaul.

With a beam forming dual antenna, one antenna looks up the street, and one down, either connecting to a small cell or being used as a relay. These relays extend the effective range to 1.5 to 2km, which further reduces the cost of rolling out a 5G network – particularly when compared to the cost of laying a dedicated fibre optic connection between each 5G Small Cell as the alternative solution

In an urban network, there is typically a mobile macro cell every 3km or so with fibre connection back to the core network. The operator can infill with two or three 5G small cells using the mmWave backhaul equipment. This can carry traffic for the next small cell so you are combining data aggregating with mesh networking in this configuration.

The strategic commercial value of O-RAN is that it allows the network system to choose between smaller UK vendors, who don’t have the complete tier one system but can provide very interesting technologies and sub-systems and allows operators to pick and mix. Operators have begun to announce network implementations, and this is an opportunity for the UK to innovate and move quickly in this key area.

The (Facebook led) Telecom Infrastructure Project (TIP) has an O-RAN programme that aims to create an accessible eco-system and demonstrate an open ‘white box’ for 5G NR radio that can be configured.

The UK Government has also announced a new ‘Task Force’ initiative aimed as increase the number of equipment vendors for mobile networks. O-RAN forms an important cornerstone of this initiative and we fully expect to play a part in this in due course.

You can find out more about Blu Wireless and how the millimetre wave systems can be used in 5G networks at www.bluwireless.com