The Wi-Fi Alliance Pushes Timing Indoors

Family in living room

The Institute of Electrical and Electronics Engineers (IEEE) does a good job of methodically increasing the distance that 802.11 – Wi-Fi – can cover and the amount of data that can be transmitted. The key now is to make sure that services within the areas covered offer the same level of quality as other wireless approaches.

The organization has taken two steps towards that goal this year.

A key challenge is that the timing of services carried over the networks must be precisely timed. The difficulty of doing this grows as the services become more sophisticated and the users more discerning. Even a small discrepancy – one that would not mean much in more forgiving scenarios – threatens to ruin the experience for uses.

In other words, people are not going to be happy if the video being sent around their homes via Wi-Fi is even a tiny bit out of sync. And it goes beyond casual users. Audiophiles are acutely attuned and able to hear subtle imperfections in the transmission of music even over short distances.

In January, the Wi-Fi Alliance confronted this challenge with the introduction of Wi-Fi TimeSync. Home entertainment perhaps is the highest profile task for TimeSync. However, the Wi-Fi Alliance says that it has many industrial, healthcare, automotive and IoT applications.

The idea is straightforward: “Wi-Fi TimeSync works by determining the offset between device clocks from a master clock, and it synchronizes accordingly,” wrote Kevin Robinson, The Wi-Fi Alliance’s VP of marketing, in response to emailed questions from Technically Speaking. “For example, if you have multiple speakers in your home theater, those speakers need to know exactly when a given tone or sound needs to come out of that speaker, and they need to do it all on the exact same clock. Wi-Fi TimeSync provides the capability for devices to synchronize their clocks so the device can provide an output on a very precise schedule.”

That may sound easy, but it is a tough challenge as speeds increase and the margin of error becomes vanishingly small. Electronic Design says it is not a new problem for the Wi-Fi sector:

The wireless audio industry has grappled with time synchronization for years. Sonos was among the first to crack the problem, using a mesh networking version of Wi-Fi that allows wireless speakers to coordinate their audio. Others have worked on a technology that shares audio by linking devices together in a loop and skipping wireless messages between them. But it still remains a key challenge, said Jaward Haider, marketing manager at Marvell Semiconductor, in a recent interview with Electronic Design.

The Wi-Fi Alliance has been busy. In late February, the organization introduced Wi-Fi CERTIFIED™ Location. It is designed to enable highly accurate (within one meter) location services indoors. The technology, which is based on fine timing measurement (FTM), can be used in retail (for instance, sending an advertisement to a customer’s device as he or she is passing that product), asset tracking (keeping tabs on expensive equipment in hospitals) and similar use cases in which precise indoor location is an advantage.

The press release says that this is done by measuring the time it takes a Wi-Fi signal to travel from one enabled device to another. This, the press release says, is far superior to the traditional ways in which distance was measured, which are either inexact or too expensive. The Wi-Fi Alliance says that products from Broadcom, Intel, Marvell, Mediatech, Qualcomm and Realtek are the first to be certified under the spec. They will be used to test interoperability.

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