MWC16: Wireless Backhaul Roundup – Will a New Approach Improve E-Band’s Tepid Popularity?

Ed Gubbins
Ed Gubbins

Summary Bullets:

  • Multiple backhaul vendors are offering (or plan to offer) new solutions that bond E-band links with traditional microwave.
  • This approach has pros and cons, but it will need to overcome the sources of lackluster market traction for E-band backhaul thus far.

In the wake of Mobile World Congress, we at Current Analysis have offered up our takes on the most important takeaways from the show in terms of new radio access networks solutions, 5G activity, IP services infrastructure and more. When it comes to the area of wireless backhaul, the most notable developments related to E-band millimeter wave technology.

A few years ago, when small-cell backhaul was a hotter topic, E-band spectrum – high-frequency millimeter wave spectrum in the spacious 70 GHz and 80 GHz bands – was heavily promoted as a small-cell backhaul technology. When the small-cell backhaul market didn’t take off as quickly or widely as hoped, vendors started pushing E-band more for macrocell backhaul, as an alternative to traditional microwave. Now, a new chapter in E-band’s story is beginning.

In early February, weeks before Mobile World Congress, Ericsson and NEC each separately announced new multi-band wireless backhaul solutions that bond traditional microwave links with E-band millimeter wave links for greater capacity. Ericsson’s Multi-band Booster and NEC’s iPASOLINK EX are the first solutions of their kind to hit the market, but not likely the last. In recent conversations, Ceragon executives say the company is also working on a similar solution, which may be unveiled early next year. And Huawei is demonstrating field trials of such a solution, branded “Super Dual Band,” with Greek operator Cosmote.

Why is this happening?

Just as lackluster market traction for E-band small-cell backhaul solutions led vendors to pitch its use in macrocell backhaul, modest market adoption of E-band macrocell backhaul has now prompted vendors to experiment with more compelling ways to use the technology. E-band comes with some drawbacks: It’s unlicensed spectrum, or in some places “lightly” licensed, meaning license requirements are minimal; that can make some operators worry about interference and reliability. E-band also doesn’t perform as well in heavily rainy climates, and it has a shorter range than traditional microwave, though vendors have been working hard to push that envelope. In any case, E-band alone as an alternative to microwave backhaul wasn’t taking the world by storm. So, a new effort is being made to see if operators will be more comfortable using E-band if it’s a supplement to traditional microwave.

Solid arguments for the new concept can easily be made: Spectrum scarcity is a constant constraint, and E-band contains wide swaths of easily available spectrum. Ever-increasing capacity needs are expected to mushroom with 5G, for which backhaul networks must be ready, and the new solutions mentioned above promise higher capacities. Pairing E-band with traditional microwave links can address some of the concerns operators may have about E-band’s reliability and availability, since operators wouldn’t need to rely on E-band by itself. In addition, the performance of E-band technology may be improving as a result of years of development among multiple vendors focused on small cells and other applications (and economies of scale may make it more cost-effective than it was five years ago). Finally, vendors’ mastery of multi-band technology is aided by existing expertise with multi-radio and channel-bonding solutions in the traditional microwave space, potentially adding an extra layer of comfort in these new solutions.

Still, this effort will face headwinds. The practice of bonding microwave links with E-band will be limited to links that are short enough to fall within E-band’s limited reach – perhaps leaving the microwave portion of these solutions inefficiently utilized. Then, there are the more philosophical questions: If an operator doesn’t fully trust E-band, that mistrust may not be dispelled simply because E-band is proposed as a supplement; an operator either needs that added capacity or doesn’t, and if they need it, they will need to trust in it. Moreover, microwave/E-band pitches might be harder to make as operators are simultaneously pitched an increasing number of multi-carrier, multi-radio solutions within the microwave domain, which promise their own capacity increases within the trusted comfort zone of fully licensed spectrum (e.g., the Harmony Enhanced MC announced by DragonWave in January).

Time will tell if operators embrace this new use of E-band to a greater degree than they did earlier proposals. For many operators, this approach may be the third time they’ve heard a new pitch for the value of E-band after having taken a pass on the first two. And that momentum (or relative lack of it) may be yet another challenge for vendors offering these solutions.


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