To be honest, I wasn't sure if Sprint (NYSE: S) was going to pull off a bonafide 5G "wow" demo before I arrived at the parking lot outside Levi's Stadium in Santa Clara, California, on Friday afternoon.

The area was teeming with soccer fans eager to see Colombia take on the U.S. and the heat – yes, it was hotter than a Finnish sauna – didn't stifle their enthusiasm one bit. Thanks to prototype provider Nokia, the heat didn't hurt the performance of the base station and other gear set up to show the potential of 5G either. The demo, which included Samsung virtual reality (VR) headsets showing 360-degree views, was pretty cool. Authenticity test: When a millennial working the security staff asked if Sprint's tent was worth the walk over there, I gave a nod of approval and a little rave about the VR demo.

Even Sprint CTO John Saw admitted that they couldn't be sure they were going to pull off the 5G demo until they arrived on the scene. "There's always an element of risk when you do this at a public event because there's no safety nets," he said.

Indeed, they didn't even need the pre-recorded video that was displayed on one big screen. The cameras set up around the staging area were able to capture the action and display it in 4K video on another big screen. Sprint execs used a panel of wood and triple-pane glass to demonstrate how beams can go around objects at 73 GHz. Beamforming and low latency applications were on full display, and soccer fans seemed to get a big kick out of the VR headsets that were available for anyone to try out. VideoStitch provided a live streaming experience that was highly responsive (with low lag) due to the low millisecond latency of the 5G system

The whole thing was a little unusual in that most of the commotion we're hearing about 5G in the U.S. is coming from Verizon. I get the impression that that's OK with Sprint executives – somebody needs to lead the charge; otherwise, the industry isn't as motivated to move on it. Having someone like Verizon out in front means everyone else needs to step up their game.

Besides putting on a successful demo, Saw confirmed something else that has been on my mind. All of this talk about 5G and how fixed wireless will be one of the first types of deployments -- an idea reinforced by the likes of AT&T and Verizon -- reminds me of Project Angel, something we covered back in the '90s. That's when I first heard Dan Hesse describe how AT&T Wireless at the time (this was the AT&T before it became part of Cingular) wanted to offer a service that would put pizza-box sized dishes on people's houses. The idea was to offer high-speed Internet, voice phone service and a home network to connect computers in the home. The idea was to take on the established phone companies, providing that all-important last-mile connection that everyone talks about.

Fixed wireless was the whole idea behind Project Angel, which Sprint CTO Saw had a hand in developing. Project Angel never did succeed like it was envisioned, and like so many things in technology, it was one of those ideas that was ahead of its time. Now it's come full circle.

A lot of the know-how survived and resurfaced elsewhere over the years. Saw and his colleagues rightly point out that Sprint's engineering team has a lot of experience and has acquired a lot of knowledge about millimeter wave and microwave for backhaul, a concept they engineered for Clearwire. The way Sprint sees it, it's got a ton of 2.5 GHz spectrum, which can been seen as the low end of the 5G spectrum, quite literally, and it's currently using higher spectrum bands, like 80 GHz, to support traffic. It's also dabbled in other high-band spectrum, like the 73 GHz that it used for the demo at the Copa game on Friday.

Looking ahead to its deployed network, Sprint says it anticipates leveraging a multitude of advanced technologies including multiple carrier aggregation, CoMP (Co-ordinated Multi-Point) with coordinated beamforming, and massive MIMO (multiple-input, multiple-output) to further enhance the capacity and coverage of its 2.5 GHz TDD-LTE spectrum.

Sprint has struggled with perceptions about its service and its network. Even while the company has improved in many areas, it takes a while for that to sink in with the public and potential old and new customers. But Sprint can go ahead and brag about its 5G demo at the Copa tournament in Santa Clara. Next up, it will be Ericsson's turn to demonstrate what it can do at 15 GHz at Lincoln Field in Philadelphia.--Monica