Vodafone says 32 is equal to 64, but better than 8

Vodafone UK cuts its massive MIMO antennas in half, to reduce power demand, as it says others will need to scale up. Plus, there's a massive spectrum refarm on the go, and is Open RAN incompatible with legacy 3G?

Operators that have chosen 8×8 MIMO to aid a faster initial rollout of 5G will regret that decision in the longer run, according to Vodafone UK’s Ker Anderson.

Anderson, Head of Radio and Performance at the operator, made his remarks at a media round table in London, as Vodafone released news that it will begin installing new 32T/32R radio units from Ericsson rather than the bulkier 64T/64R panels it has used to date.

As soon as we run down the 64T/64R stock we will be rolling out the 3227.

Up until now Vodafone has made a virtue of its use of 64T/64R 5G active antennas. Anderson himself, writing about a year ago about the operator’s 5G rollout in London, said, “We are the only operator to exclusively deploy 5G using 64×64 MaMIMO, and using Ericsson technology and our network, we have delivered a strong, solid and reliable 5G service.”

Today, Vodafone said it would be installing 1,500 new Ericsson units – known as AIR 3227 – by April 2022. They weigh about half of the 64T/64R MIMO units and use about 43% of the electricity, Anderson said. (The old units were about 60kg and “burnt electricity for fun”, he added.) “As soon as we run down the 64T/64R stock we will be rolling out the 3227.”

I don’t think the 5G rollout is the game of who rolls out the fastest

He added that due to technical improvements since Ericsson first rolled out the larger antennas, the 32T/32R MIMO Radio Units can give the same performance as the older, higher order units. That means that Vodafone can reduce the associated physicals and steelwork at sites, with a much lower wind loading on the site. Because Massive MIMO antennas steer beams, they need to be sited at the edge of buildings, increasing the difficulty of siting and securing heavy equipment and putting a premium on lighter and smaller equipment.

Anderson added that Vodafone is still backing its higher order MIMO strategy as it upgrades sites.

“We’ve always fundamentally believed that building in the right solution for 5G from day one is the right thing to do. We don’t want to be going back and constantly updating. Now, other operators have deployed quick and dirty, eight by eight panels, to get by quickly and they’re claiming quite a high percentage of 5G. I think they’re possibly going to regret that and I think they’re going to end up going back and having to upgrade the cell sites. We made the decision to go future-proof from the beginning, meaning that it’s slower, but I don’t think the 5G rollout is the game of who rolls out the fastest, necessarily.”

Does mass O-RAN necessitate 3G switch off?

Anderson also presented on another aspect of Vodafone’s ongoing network rollout, the re-farming of 900MHz spectrum away from 3G to 4G.

The operator now has just a single 5MHz carrier set aside for 3G, with very nearly 10MHz of the band now re-dedicated to 4G. Anderson said that 4G at 900MHz spectrum increases range and in-building penetration compared to 2100 MHz and 2600 MHz bands, and can offload congestion from the 800MHz band. Achieving the re-farm meant the operator has “completely retuned the 2G network over the past couple of months – retuning thousands and thousands of sites every single night.”

The operator anticipates it may need to keep 3G alive for another five years or so to support devices that require 3G for voice and also for data, even though 3G traffic is less than 5% of the total, and continues to decrease.

Anderson said that this ongoing demand for 3G may actually impact the introduction of O-RAN at scale, as Vodafone does not judge that O-RAN can support its legacy 3G users. This is something that O-RAN providers Parallel Wireless and Mavenir (since it integrated ip.access assets) might dispute, with both vendors consistently highlighting their ability to provide Multi-RAT service from their O-RAN platforms. Vodafone, however, has Samsung as its O-RAN vendor for its first tranche of O-RAN, which does not provide 3G support.

So, as Vodafone needs to keep 3G going for a while longer, it seems likely that it will only introduce O-RAN in areas where it can either keep a separate 3G radio on air (difficult, and perhaps not very likely) or where it deems it can turn 3G off. That may mean that its rural and semi-rural Huawei site replacement programme sees the majority of sites replaced towards the end of the operator’s 2027 deadline, or as 3G is turned off, whichever comes first. The operator has a commitment to swap out 2,500 Huawei sites, and has previously said it will have over a thousand of those swapped out in favour of its O-RAN platform by the end of 2023.