On Wed, Mar 27, 2019 at 2:05 PM Bryan Fields <Bryan@bryanfields.net> wrote:
Looking at the typical equipment used (64 QAM, 20 MHz channel), you're going to have a raw bitrate of around 80 mbit/s. Couple this with overhead and some inevitable interference and an access point will have about 50 mbit's of large frame capacity. This is not much, and every client added will slightly reduce this due to multicast and supervisory signaling losses. Each system is going to be Time Division Duplex (using the same channel for transmit and receive), so you will split this say 75/25 down/up stream. This means you have at best 37.5 Mbit/s available for all clients to share, which isn't much for a 90 or 120 degree sector out to 10 miles (or more) depending on density.
Ahh, and there's your misunderstanding. Most good WISPS deploy equipment which is capable of much more, with much smaller cell sizes anymore. 256QAM is the rule, 3 Miles is a large cell size, and with MU-MIMO enabled AP's you can get aggregate of around 500MB/s on a single 20Mhz wide channel. If you can find 40Mhz, it's over 1GB/s. Of course, this depends on the exact equipment deployed. Even with lower-end equipment most operators end up with 200Mb/s in 40Mhz - and will often limit the number of customers on that 200Mb/s AP to a dozen or so. You need to be aware that the industry has grown up a LOT in the last 4-5 years, but like in any industry there are bad and good operators. Some do fit into the category you're describing, but from what I can see a large portion of them do know how to deliver a lot of bandwidth. In addition, many WISP's are now also trenching fiber to the home where it makes sense, and deploying fixed wireless where it doesn't. Often the fiber trenching is being driven by those sites where the aggregate customer bandwidth needs do outstrip the capability of the wireless network. -- - Forrest