Capacity v. Coverage: The Rivalry

Maybe “rivalry” is not the right word, but it sounded catchy to me and we all know catchy headlines grab the reader’s attention 🙂 . This summer, I had the privilege of volunteering at the U.S. Open at Pebble Beach, CA. For those that aren’t familiar with golf, the U.S. Open is one of four major tournaments held during the season and it attracts hoards of fans and media from around the globe every year. It was my third year volunteering at the U.S. Open (2011 – Congressional in Bethesda, MD; 2014 – Pinehurst, NC) and the first “connected course” that would not only feature pervasive wireless and Cisco Vision, but Cisco’s first test of WiFi 6 at a sporting event.

Upon reading this before I traveled out to California, it made me even more pumped to get to the legendary grounds at Pebble Beach. The excitement of the event and the location distracted me towards the Merchandise tent once I arrived, but once I went over budget in there, I made my way around the course. My duties for the week were to work as a Laser Operator measuring the distance off the tee for each player, as well as measuring the distance remaining to the hole for each player as they played through the 9th hole. The laser was a Trimble laser much like those seen perched atop a tripod being used by a roadside survey crew. The data was was captured and put in to a user interface on custom software using a Panasonic Toughpad.

Wifigolfer at his post on the 9th hole at Pebble Beach…it was cold.

Now, on to the wireless experience. As a guest, I found that coverage was pretty pervasive, for the most part. In my experience with designing outdoor wireless for high-density, it is a difficult task to merge capacity and coverage in an outdoor environment, especially one like an open golf course which has little to no attenuation that you can use to your advantage, let alone places to mount antennas. Before I go on, I want to say that I am only going on what I have read about this system from Cisco and have no insight in to what the actual requirements were from the USGA (the customer). This post, is in no way critical, but more of a perspective from a user who is experienced in these type of deployments.

Throughout the facilities and out on the golf course I was pleased to see a familiar face with the Meraki APs (possibly the MR84) and what looked to be the Cisco AIR-ANT2513P4M-N= high-gain (13dBi) patch antenna, that is 27-33 degrees on the E-plane and 31 degrees on the H-plane. An interesting selection, but it looks like they were trying mitigate the fact that there were little to no attenuating factors, thereby minimizing the overlap of the RF footprint in the immediate area.

I found that this setup was pretty much what was used throughout the entire course and other outdoor areas. As you can see from the picture above, antennas were mounted on tent setups (merchandise, food, info tents, etc.) as well as TV towers located throughout the course.

As I walked the 30+ minutes from the Volunteer tent to my post at the 9th hole I fired up a few golf highlight videos on Youtube and tested out streaming while roaming. I found no issues and didn’t get the dreaded “buffering” or “loading” image while watching and browsing Youtube, other than one remote area, which was a secondary walkway between the 5th and 6th holes. I also ran one of my go to test links for video from Netflix. Again, no issues as I walked around the course, tee to green, tee to green, all the way to the 9th hole and back.

I decided to run a speedtest while at a location where it was just myself and a few other guests standing around near the 14th green and got the folowing results, which is more than adequate if they were hoping to have guests be ale to use the plethora of media they were advertising throughout the grounds (social media, event app, shot tracers, streaming video). The RSSI at this location was at -67dBm, if memory serves me correctly, which is within the general spec for signal strength for high-density wireless for Cisco.

A few days later, I ran another speedtest while waiting in line at a concession stand. This stand had a similar AP and antenna setup on the corner of the tent, like the one pictured above, that was intended to service those of us in line (based on the orientation fo the antenna). I would say there was about 6 lines of about 12 – 15 people deep, so this small area between the 12th green and 13th tee had the potential of about 72 – 90 users. I quickly jumped online and connected to the guest wireless SSID with no issue. I then tried my Youtube list of highlight videos again and this time, all i was able to watch was the little spinning icon. I looked at my RSSI and it was -63dBm, which says to me that coverage was not the issue, so over to speedtest I went to see what kind of bandwidth I was getting. As you can see from the results below, the AP I was connected to was very busy in some capacity.

To me, this appears that even though my RSSI (-63dBm) was well within spec for high-density wireless best practice, according to Cisco, my SNR must have been abyssmal. My estimation is that my SNR at this point was most likely in the low teens, if not in the high single digits. Most likely due to the fact that I was one of about 50+ devices trying to compete for air time in a very condensed area (Retry, Retry, Retry).

All in all, my wireless experience was good, with the exception of condensed areas where the capacity may have been over the limit of what was planned or designed for. I didn’t get to experience any of the Wifi 6 goodness, as I do not have a compatible client, but I did not see any Wifi 6 capable APs out on the course. My guess is that those were probably installed inside suites and the media tent. This is a great foundation for the “connected course” and I look forward to seeing how this improves over the years and when I get to volunteer at my next U.S. Open.

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