Telus starts massive 'multivendor' open RAN rollout with Samsung

A prominent victim of the Canadian clampdown on Huawei, Telus previously did a rapid switch from full reliance on the controversial Chinese vendor to the use of Ericsson, Nokia and Samsung. By 2022, it was boasting a 5G network that covered more than 80% of the population. But the operator has continued to project enthusiasm for newer open and virtualized radio access network (RAN) technology. This year, it announced today, it will start work on a major 4G and 5G rollout led by Samsung.

The plan is to "hit cruising speed" later this year and have converted between 40% and 50% of all mobile sites to virtual RAN technology by the end of 2027, said Bernard Bureau, the vice president of wireless strategy and 5G services for Telus. That does not mean immediately ripping out what has been recently installed. In areas where Samsung is present, Telus believes it can use a "converter" to switch from the old "closed" fronthaul specification (CPRI) to a more open eCPRI update. "We have the ability to continue growing our open RAN and virtual RAN footprint within the sites that are today the traditional RAN sites," Bureau told Light Reading.

On top of that, the 83% 5G coverage figure cited in the 2022 annual report largely concerns the use of frequency division duplex (FDD) spectrum for less advanced 5G services. "We haven't deployed massive MIMO on all our sites," said Bureau, referring to the antenna-rich 5G technology used in other spectrum bands, including the 3.5GHz range.

Samsung is to provide both radios and baseband software for this massive MIMO rollout, meaning there has been no attempt there to combine different vendors. While "happy" with the South Korean supplier, Bureau says this "single vendor" decision was partly down to the "specificities" of the Canadian market. "We have two bands adjacent to one another – it starts at 3450MHz and it ends at 3900MHz – and we needed to have a radio covering the full 450MHz with sufficient power to have 200MHz enabled within it," he said. "It was difficult to find another supplier."

Mystery vendor

Nevertheless, Telus insists its overarching plan is not a "single vendor" one, where products are compatible with specifications but all supplied by the same player. "Half of the FDD radios are with a third-party radio supplier, the other half are with Samsung and we are doing massive MIMO with Samsung," Bureau explained. "Two out of the five radios on a sector basis are third party, and the other three are with Samsung."

Telus needs lots of radios because it is running 4G services in eight frequency ranges besides bringing three spectrum bands into use with 5G: 600MHz; AWS (using 2100MHz for downlink and 1600MHz for uplink); and 3.5GHz. But the identity of the other radio supplier, whose radio unit (RU) hardware will be linked to Samsung's distributed unit (DU) software, is not being disclosed at this stage for contractual reasons.

What Telus will say is that it's an "emerging" player and not a company that had previously done integration work with Samsung, ruling out both Fujitsu and NEC. The operator also appears to have led work on integration, with Bureau downplaying the effort involved. "There are lots of people in the industry who say integration between the RU and DU is super complicated and a huge burden, but I think the maturity of the ecosystem has improved."

Integration took up to 18 months when Telus started out experimenting with open RAN, but it was possible in just six weeks at the last attempt, according to Bureau. His broad message to the market is that if integration can be managed by a relatively small player like Telus, which lacks the heft of Chinese and US telcos, then other telcos should be able to handle it, too.

That seems to contrast starkly with the view of Robert Soni, a technology executive at AT&T, who last year said telcos would only be able to challenge the "closed ecosystem world" if they pooled resources. Soni reckons Ericsson invests about $3 billion a year in RAN research and development and that as much as a third of this goes toward integration and validation. For AT&T's own "open RAN" deployment, Ericsson appears to be playing the systems integrator role as well as providing most of the components.

"People still think that integrating radios will be a complete nightmare, which it is not, in my opinion," said Bureau. "For context, Telus is big in Canada, but not as big as Verizon and other giants, and we are still able to meaningfully play a role and integrate. I think there has been some very negative documentation and messages sent by some industry players about integration."

When it comes to massive MIMO, Samsung's equipment today is based on the original 7.2x specification that came out of the O-RAN Alliance, the telco-led body that steers technology development, according to Stephen Witorski, the head of networks for Samsung Canada. The vendor is, however, keeping an open mind about the different options nailed down last year during a meeting in Osaka, he said. In short, these are about the distribution of uplink functions between the DU and the RU. They arose out of concern the original specification, which keeps all those functions in the DU, would lead to performance problems.

"Our policy is to be open minded, and the decision was based on data and how 7.2x does in the market, and we won't make any decision without consultation with customers," said Witorski. "If we need to go there and that is best for the industry, we can," he added in reference to the compromises reached in Osaka.

No proprietary hardware, please

Samsung is also running its virtual RAN software on general-purpose processors supplied by Intel on HPE servers, with minimal "acceleration" for more resource-hungry functions. This was evidently good enough in performance tests for Bureau, who is highly critical of alternative acceleration techniques based on the use of custom silicon.

"We are very happy with Samsung, but if something happened in future, and we wanted the hardware for a different network functions supplier, we would have the ability to do that, which is really core to O-RAN Alliance principles," he said. "If you look at other offerings, some suppliers are insisting on proprietary hardware DUs and saying that is the only way you can get the performance. We are proving it is not."

This sounds like bad news for Nokia. The Finnish vendor is using custom Marvell chips as accelerators for the most resource-hungry "Layer 1" RAN software and has acknowledged this code would need to be rewritten if another hardware player were introduced. In virtual RAN deployments, those Marvell chips are hosted on PCIe cards that would slot into servers. Ericsson, the other RAN vendor in the Telus network, backs the same approach as Samsung.

Earlier this week, the South Korean vendor highlighted a DU partnership with Intel rival AMD, and Witorksi says the same DU software written for Intel processors can be redeployed on AMD's chips with minor reconfiguration. "We are committed to having diversity on silicon and we couldn't do that if we had to rewrite the software from scratch every time we wanted to bring in a new chip vendor," he said. Ericsson has previously made similar comments when highlighting partnerships with Intel and AMD.

Both vendors have professed interest in Arm, a rival architecture to the x86 platform used by Intel and AMD. Writing code that can be deployed on either x86 or Arm with only minor reconfiguration is likely to prove harder, according to experts. Yet for both Samsung and Telus, diversity in all areas seems of paramount importance.