Qualcomm engineers demonstrate millimeter wave design for 5G

In an early public demonstration of its TDD synchronous system operating in the 28 GHz band, Qualcomm Technologies (NASDAQ:QCOM) recently showcased the kind of intelligent beamforming and beam tracking techniques that could be part of 5G networks.

The Nov. 17 demonstration for industry analysts took place at Qualcomm facilities in San Diego, but the company also has done a lot of millimeter wave (mmWave) R&D at its facility in New Jersey, according to Matt Branda, director of technical marketing at Qualcomm Technologies.

Bands above 6 GHz traditionally have been good for point-to-point, line-of-sight type applications, whether it's indoor video streaming or outdoor backhaul access. "It's traditionally not been possible to utilize it for mobile broadband type applications, and that's the work the team in New Jersey has been working on," building a prototype for conducting measurements. "In a lot of ways, those bands are kind of the great unknown when it comes to moving them into these types of deployments."

Industrywide, a lot of public mmWave demonstrations have been conducted, including at the last Mobile World Congress trade show, to show the kinds of multi-gigabit rates that are possible. "The real challenge is being able to show technologies that can allow millimeter wave to operate in non-line-of-sight," or more mobile environments where people are moving around, and "that's really what we were demonstrating with the 28 GHz system," he said.

Considered a key 5G technology enabler, mmWave operates in higher frequencies, where a large number of antennas are required. But the higher frequencies traditionally were not determined to be robust enough for indoor/outdoor mobile broadband applications due to their high propagation loss and susceptibility to blockage from buildings and other objects -- even rain drops.

The demo by Qualcomm Research engineers included one mmWave base station and one end-user device, although the system was designed to handle multiple devices. The mmWave base station antenna design prototype had 128 antenna elements with 16 controllable RF channels while the device contained four selectable sub-arrays, each with four controllable RF channels.

The engineers wanted to show how using intelligent, directional beam forming can be used to "mobilize" millmeter wave so that it can be used when people might want to move around in a non-line-of-sight, dense, urban environment.

The 3GPP held a 5G workshop in September and one of the study items kicked off was channel modeling efforts on millimeter wave. NYU Wireless has been heavily involved in contributing measurements and has been one of the most active participants in promoting milllimeter wave technologies. Qualcomm's New Jersey-based team also has contributed measurements, Branda said. Measurements involve everything from outdoor environments, indoor malls and residential settings, as well as indoor-to-outdoor and testing from 22 up to 67 GHz and beyond -- both line-of-sight and non-line-of-sight.

One of the key learnings Qualcomm engineers shared from their outdoor measurements is that at millimeter wave frequencies, some of the alternative non-line-of-sight paths -- which involve signals bouncing off buildings or other structures -- are more high energy than a line-of-sight path, Branda said. That allows for using those non-line-of-sight paths in a different way than your traditional uses in sub 6 GHz.

Qualcomm is expected to showcase more of its mmWave capabilities at next year's Mobile World Congress 2016 in Barcelona.

In July 2014, Qualcomm announced that it had completed the acquisition of Wilocity, a developer of 60 GHz wireless chipsets based on the IEEE 802.11ad standard, and introduced a family of tri-band platforms that combine Qualcomm Atheros Wi-Fi and WiGig solutions to increase performance and enable more cutting-edge wireless applications. The initial tri-band platform was a reference design based on the Snapdragon 810 for supporting applications like 4k video streaming. WiGig was originally developed in the WiGig Alliance, but it joined up with the Wi-Fi Alliance in 2013 and it's now certified through that organization for the 802.11ad standard.

For more:
- see this Qualcomm blog

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