NF: Is there a “recipe for success” for keeping up with the telecommunications providers in terms of semiconductor development?

MN: The relationship between telecom providers and semiconductor vendors needs to be symbiotic. Telecommunications providers need to rely on semiconductor suppliers to deliver the technologies requested by the systems OEMs. Otherwise, they will not get these technologies. On the other hand, the semiconductor vendors have the best view of what is possible and cost effective to do in what timeframe. Often, the service providers don’t even know what is possible, so they are not considering technologies that would make their lives a lot easier. So we need to have a constant give and take between service providers and semiconductor companies beyond the direct supplier/customer relationships that exist between semiconductor vendors and systems OEMs—and between the OEMs and the telecommunications providers.

NF: Can you update us on how time errors are now being defined within HetNets?

MN: One of the biggest problems we had identified in the past for HetNet deployments was 1588 timing delivery over mixed fiber/microwave/small-cell/macro-cell radio-access networks. Although there is an overall time error budget of 500 ns maximum between adjacent cell sites [in the case of LTE-Advanced Coordinated MultiPoint (CoMP), for example], operators never were able to determine if their access networks would meet those targets before they were done deploying the networks and were able to test them. And various network elements and backhaul technologies today have very different abilities to maintain 1588 timing, so there would be a significant amount of finger pointing if the network did not meet the specs.

Now, the ITU has stepped in and is in the process of defining time-error equipment classes for each network element. The maximum time error that can be introduced by a 1588-compliant router, switch, or microwave backhaul link is 50 ns. Some operators are pushing to define a second timing equipment class with a maximum time error of 20 ns. This way, operators can literally just add up the time-error classes for each link and know if they are within a specific timing budget before they build their network. This will be particularly important for HetNet deployments (where there could be equipment from many different vendors) and even third-party operators in some segments of the access network, as we discussed.