Researchers at NYU Wireless said their work has revealed important limitations in current commercial 3GPP approaches for channel models, and they said failure to update the models to reflect the realities of millimeter wave (mmWave) propagation could cost U.S. customers and commercial service providers millions, if not billions, of dollars in deployment costs.
"We ask the FCC and other U.S. government agencies and universities to become active in ensuring that future 3GPP standards for propagation/channel models are suitably and accurately defined for the mmWave bands, and that the 'status quo' in modeling is not maintained in the 3GPP standards body, simply out of convenience, or out of pride of past ownership, or out of fear that the ITU will not appreciate the realities of mmWave propagation," wrote NYU Wireless founding director Ted Rappaport in a filing with the FCC.
It's a subtle but important point for the welfare of future equipment designers, implementers and users of future mmWave spectrum in the United States, he said.
Using the "old" way of channel modeling in 3GPP that relies on a very rapid model development cycle -- without thorough consideration and use of careful, peer reviewed results in the literature by leading universities -- will degrade the standardized channel models that all manufacturers will use in designing and testing/comparing new products and algorithms for the mmWave bands, the filing said.
Rappaport also noted that the channel models in past 3GPP standards bodies have been dominated by European and Asian influences, often in forums that do not use a peer-review system. He said there is the potential danger of encountering a "not invented here" mentality when it comes to allowing the U.S. and North American constituents to provide input, advice and influence for mmWave 5G channel models. That's because the U.S. has been notably absent in the past and there is no "national convener" or nationally organized government-sponsored entity for channel modeling or wireless standard development in the U.S., as there is in Europe, via COST, WINNER and METIS, for example, or with MiWeba in Asia.
Given 3GPP's recent approval for an official mmWave study group and channel modeling activity, "the time is now for the FCC to call attention to the importance of capturing realistic and analytically tractable channel behavior… and to insist that mmWave standardization not be tied to the 'status quo' that has had little U.S. participation in the past," the filing concluded.
NYU Wireless researchers were granted an experimental license for channel measurements at mmWave frequencies and their ongoing work has found the 28, 38 and 73 GHz bands to be especially viable for mobile service.
- see this FCC filing
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