Schoolar: Multi-mode LTE getting a fresh look from operators

Daryl Schoolar ovum

Daryl Schoolar

Looking back at the "What to expect from MWC 2014" column I wrote in early February I would say the conference met my expectations. I want to say I'm the world's greatest prognosticator but that would be a lie. Surprises are rare with wireless infrastructure. Vendors often give me a heads up on what to expect and having watched this market for some time I can tell you that if one or two vendors are doing something, you can be sure their competitors are working on something similar. But, that isn't to say I didn't encounter a surprise this past February while in Barcelona.

Ovum has been on the record talking about the value of multi-mode LTE (FDD +TDD) networks. Using TDD spectrum along with FDD spectrum will increase an operator's network capacity. It can also save the operator money as TDD spectrum has historically come with a lower price tag than FDD spectrum. Constructions of multi-mode LTE networks are already under way, most noticeably at Sprint in the U.S. Sprint's owner Softbank (Japan), China Mobile Hong Kong and Swedish operator 3 have all deployed multi-mode LTE networks as well. While the list of multi-mode LTE network deployments is respectable, they are by far in the minority of total LTE deployments. Out of 264 commercial LTE networks at the end of 2013, only 11 were multi-mode. It looks, however, based on observations at MWC 2014, that could change.

Steve Pusey, Group Chief Technology Office, Vodafone spoke at the annual GTI (Global TD-LTE Initiative) summit held at MWC 2014. Steve spoke about how his company owned unpaired spectrum in multiple countries across Europe including the UK and Spain. He also talked about how deploying LTE TDD would benefit the end-user by increasing network capacity. I would take his presence at the GTI summit and his praise of LTE TDD as a good indicator that Vodafone was seriously considering deploying a multi-mode LTE network.

Another strong indicator of Vodafone's interest in multi-mode LTE came from a demonstration it participated in with Huawei. The two companies showed carrier aggregation between LTE FDD and TDD achieving a down link speed of over 500Mbps. No surprise, this wasn't the only announced demonstration of this type.

NSN announced that it had done a similar LTE FDD + TDD carrier aggregation demos in South Korea with both SK Telecom and Korea Telecom. It is worth noting that both Huawei and NSN are LTE RAN vendors for SK Telecom. Coincidently, Vodafone, as part of its Project Spring LTE buildout, has selected both Huawei and NSN as suppliers.

Vodafone hasn't come out and officially said it will deploy multi-mode LTE networks, but it sure looks that way. Both China Unicom and China Telecom will have multi-mode LTE networks, but given China's role in promoting LTE TDD, that isn't surprising. But, I will say I was surprised at the activity around multi-mode LTE networks at MWC. Given the strong interest shown at the conference, I think there will definitely be others.

The strong interest in multi-mode LET wasn't something I was expecting, at least at this date, but I am pleased to see it nonetheless. It only makes sense. Operators constantly beat the drum for more spectrum, and unpaired spectrum remains underutilized. If the two modes of LTE can be aggregated together to increase capacity, it would be a major benefit to operators. Some operators may even go down the multi-mode path as a way to delay some small cell deployments. This is definitely a trend worth paying more attention to.

Daryl Schoolar is Principal Analyst of Wireless Infrastructure for Ovum. Daryl's research includes not only what infrastructure vendors are developing in those areas, but how mobile operators are deploying and using those wireless networking solutions. Contact him at [email protected] and follow him at @DHSchoolar.