Wireless ISPs (WISPs)

[swwifty]

Thought I'd start a thread to discuss WISPs. I think a lot of folks that are technical and setting up 4G conections are probably learning about WISPs in the process. They are very common in rural areas now to solve the rural broadband problem.

Part of my adventure into 4G as a home internet connection led me into starting a WISP. Feel free to discuss here/ask questions. I can provide links to more info on it, but if you live in an area that has poor internet more then likely you can start a WISP to help your community.

[JimHelms]

Great idea.

[swwifty]

A few resources to get started:

http://www.wispa.org/

http://wisptools.net/ebook.php

[xdavidx]

Thanks for starting this. I'd be very interested in hearing more details about contacting tower owners and leasing space. What the contracts are like (duration, pricing, etc.). Equipment used for the hops to get closer to the customers (tower to tower) and equipment used from tower to customer would be cool to hear about too. Frequencies, speeds, etc. would be fun too.

[swwifty]

Thanks for starting this. I'd be very interested in hearing more details about contacting tower owners and leasing space. What the contracts are like (duration, pricing, etc.). Equipment used for the hops to get closer to the customers (tower to tower) and equipment used from tower to customer would be cool to hear about too. Frequencies, speeds, etc. would be fun too.

It's quite complicated when it comes to tower leasing. A lot of tower companies are interested in leasing to WISPs now, but the logistics and planning are very complicated. I could probably have a thread just on tower leasing. While this site is a bit dated, it's still very useful: https://startyourownisp.com/

The main two companies in the WISP hardware industry are Ubiquiti and Cambium Networks. I did some basic longer range testing this weekend with some CPEs (Customer premise equipment) off a mountain I'm going to be going on, and a location about 3.5 miles away. This was just a point to point connection, and not a point to multipoint which is what most sectors cover/serve. I was basically trying to do some spectrum analysis and see how much throughput I could manage even with the cheap CPEs and not a real AP and sector antenna. Aggregate throughput for both was about 110mbps on a 20mhz channel. Below are some screenshots for everyone's enjoyment, and links to the datasheets on the hardware:

https://dl.ubnt.com/datasheets/LiteBeam ... en2_DS.pdf

Ubiquiti Status Page:

Screenshot from 2019-07-13 11-23-46.png

https://www.cambiumnetworks.com/product ... ce-300-16/

Cambium Connection page:

Screenshot from 2019-07-13 11-56-21.png

A picture from where I was testing at:

2019-07-13.jpg

[xdavidx]

I could probably have a thread just on tower leasing.

Looking forward to it!

I did some basic longer range testing this weekend with some CPEs (Customer premise equipment) off a mountain I'm going to be going on, and a location about 3.5 miles away.

So this is a CPE antenna to a CPE antenna?

Aggregate throughput for both was about 110mbps on a 20mhz channel. Below are some screenshots for everyone's enjoyment, and links to the datasheets on the hardware:

Cool. What does aggregate throughput mean here? Does that mean total throughput when sending and receiving at the same time? Were you able to do 40 MHz at that distance, or did that degrade the signal too much?

Are you testing the Ubiquiti vs Cambium? Did one work better than the other?

Thanks for sharing the screenshots and picture.

[swwifty]

Looking forward to it!


So this is a CPE antenna to a CPE antenna?


Cool. What does aggregate throughput mean here? Does that mean total throughput when sending and receiving at the same time? Were you able to do 40 MHz at that distance, or did that degrade the signal too much?

Are you testing the Ubiquiti vs Cambium? Did one work better than the other?

Thanks for sharing the screenshots and picture.

Yes, this was just cheaper CPE equipment connecting to each other in a point to point connection.

Aggregate throughput here means the total throughput possible on the channel transmit and receive combined, like you mentioned. Wifi chipsets normally transmit and receive on the same frequency. That means they are half duplex (they can only transmit or receive at any given moment, not both at once.) This is referred to as time division duplex (it's a form of multiplexing)

LTE in the US is typically frequency division duplex (FDD) which is a different frequency for transmit and a different frequency for receive. A good guide to this can be found at: https://www.cablefree.net/wirelesstechn ... dd-vs-tdd/

It's good to understand this, because FDD enables full duplex, while TDD is only half duplex. They have pros and cons that are too long to detailed here.

The Cambium CPE seemed to perform much better surprisingly. Especially cause the gain on the antenna is 7dbi less, which added up to 14dbi (when you add it the other CPE) for the link!

I didn't try a 40mhz channel, cause I likely won't use channels that wide as I want to save spectrum. Channel sizes have pros and cons. The wider the channel is the more noise it will pick up, and the tx power is spread out across a wider channel. This means effectively that the SINR will likely be lower, than a narrow channel. It really all depends on how long the link is, and what kind of link budget (how weak the signal is where you are, and how much the signal can degrade before you have a link outage) you have. The WISP guide I posted earlier explains some of this, but this is a complex topic in RF engineering. The wireless channel is a very interesting engineering topic, as it's a lot more dynamic and variable than for example, a copper or fiber cable!

[xdavidx]

Aggregate throughput here means the total throughput possible on the channel transmit and receive combined, like you mentioned. Wifi chipsets normally transmit and receive on the same frequency. That means they are half duplex (they can only transmit or receive at any given moment, not both at once.) This is referred to as time division duplex (it's a form of multiplexing)

Yep, that's why I was wondering if that is what you were testing. Do you get about 200 Mbps in one direction then? Is there any way to restrict upload speeds so that people doing uploads don't slow down the downloads for others as much?

The Cambium CPE seemed to perform much better surprisingly. Especially cause the gain on the antenna is 7dbi less, which added up to 14dbi (when you add it the other CPE) for the link!

What was the performance difference?

I didn't try a 40mhz channel, cause I likely won't use channels that wide as I want to save spectrum.

What is your target speed for end users? Will you have different speeds that you can restrict the system to and different prices for the different speed levels? How do you deal with them sharing bandwidth with each other on the same channel (when you have sector antennas and ptmp instead of ptp)? Is this handled through restrictions, or will each user just expect to get 1/N the bandwidth, where N is the number of active users at any given point in time?

The sharing aspects are what I pondered a lot when thinking about the possibility of setting up something like this. If you have a captive audience, where they don't have any other option, then that's one thing. But if they have DSL or cable availability (speaking in general, not your situation), then restricting them or sharing the wireless pipes is a harder value proposition.

Do you expect to see similar speeds with sector antennas? Do you have to run different sectors (from the same tower) on different channels? That's one thing I never looked into much. I thought there was a concept of using shielding, but I'm not sure if that was between sector antennas or how that came into play and whether that would allow the same channel to be used by different sectors.

The wireless channel is a very interesting engineering topic, as it's a lot more dynamic and variable than for example, a copper or fiber cable!

Yes, it is! Tons of variables. At least the Ubiquiti software has a lot of smarts in it to help (from the research I did in the past). Never looked at the Cambium stuff to know how it compares in that regard.

[swwifty]

Yep, that's why I was wondering if that is what you were testing. Do you get about 200 Mbps in one direction then? Is there any way to restrict upload speeds so that people doing uploads don't slow down the downloads for others as much?


What was the performance difference?


What is your target speed for end users? Will you have different speeds that you can restrict the system to and different prices for the different speed levels? How do you deal with them sharing bandwidth with each other on the same channel (when you have sector antennas and ptmp instead of ptp)? Is this handled through restrictions, or will each user just expect to get 1/N the bandwidth, where N is the number of active users at any given point in time?

The sharing aspects are what I pondered a lot when thinking about the possibility of setting up something like this. If you have a captive audience, where they don't have any other option, then that's one thing. But if they have DSL or cable availability (speaking in general, not your situation), then restricting them or sharing the wireless pipes is a harder value proposition.

Do you expect to see similar speeds with sector antennas? Do you have to run different sectors (from the same tower) on different channels? That's one thing I never looked into much. I thought there was a concept of using shielding, but I'm not sure if that was between sector antennas or how that came into play and whether that would allow the same channel to be used by different sectors.


Yes, it is! Tons of variables. At least the Ubiquiti software has a lot of smarts in it to help (from the research I did in the past). Never looked at the Cambium stuff to know how it compares in that regard.

Both the Ubiquiti and Cambium radios got about 110mbps aggregate, so max of 110mbps one direction.. They also both weren't hitting 256qam in a 20mhz channel and were only at 64 qam modulation. I suspect if they could get closer to 130mbps if they hit max modulation rates.

The cambium radio got a stronger signal, but more importantly seemed to be more consistent on throughput.

I'll have a few different plans that will be limited to their speeds via QoS. End users don't know about the entire sectors capacity. Typically a wireless sector is oversubscribed 10 to 1, without impacting actually throughput. This is can work because the average home user at peak times only uses about 10mbps/sec, even if they have a 1 gig connection! This is why one gig connections are a home are total gimmicks (well for now at least, until someone creates something that requires that much throughput)

I'll most likely start out with a couple of sectors. Frequency re-use in these products is possible typically with ABAB use. This is another huge complex topic, but basically 4 sectors can use 2 channels without interfering with each other, specifically while using a GPS sync feature. This is where LTE is much better as it can support frequency reuse of 1 (aka same channel on every sector). This is really important to carriers who pay millions for their spectrum.

[xdavidx]

Both the Ubiquiti and Cambium radios got about 110mbps aggregate, so max of 110mbps one direction..

Sorry, I'm not understanding this. If they got 110 Mbps aggregate, and if aggregate the total of the send speed plus the receive speed, when sending and receiving at the same time, then how is it 110 Mbps in one direction when not sending in the other direction at the same time?

They also both weren't hitting 256qam in a 20mhz channel and were only at 64 qam modulation. I suspect if they could get closer to 130mbps if they hit max modulation rates.

Distance was too great, or needed to be pointed better, or the channel was too noisey from other systems around there? Why do you think it wasn't able to hit the higher modulation?

Typically a wireless sector is oversubscribed 10 to 1, without impacting actually throughput. This is can work because the average home user at peak times only uses about 10mbps/sec, even if they have a 1 gig connection! This is why one gig connections are a home are total gimmicks (well for now at least, until someone creates something that requires that much throughput)

Hey, if they don't have any other way to get internet, then I suppose 10 Mbps would seem pretty darn nice. With just simple math and ignoring possible slowdowns from multiple users hitting it at the same time, and slowdowns from spreading the signal out over a wider beam width with sector antennas, that's 110 users over that 110 Mbps link (or more, depending on your answers about single direction speeds). In a sparsely populated area, that seems like a lot of people!

I agree about the 1 Gbps not being totally necessary. I am looking forward to faster speeds than my 10 Mbps DSL here, with my LTE setup, because:

A) I have multiple people in the house who stream video at the same time. We got rid of our satellite TV service a few years ago and all our TV is through streaming now. Not to mention Youtube use by my kids.
B) It allows for 4K video, which wants about 25 Mbps. I don't have any 4K TVs yet, but I'm sure in the future I will eventually.
C) You can never have enough speed for large things that need to be fully downloaded, like software installation files, software updates, non-streaming video files, tons of digital images (moving stuff around for home movies/photos), etc.

But if people are brand new to the internet, (A) and (B) probably aren't going to matter to them and (C) is more of a unique thing for someone who does a lot of computer work.

In my area, there are others who have access to cable (I don't), so it would be very difficult for me to compete with that if I wanted to set up a WISP. I could compete with the phone company on the DSL no problem, since the speeds are slow and the service is horrible. There might be some more rural areas here where they don't have access to cable. I'll have to ponder that a bit. I do know that I used to check for any WISPs that might have sprung up, every few months, praying that something other than DSL would become available to me. I did that for *years*! So discouraging to have no other options. I'm sure there are others who feel the same way.

I'll most likely start out with a couple of sectors. Frequency re-use in these products is possible typically with ABAB use. This is another huge complex topic, but basically 4 sectors can use 2 channels without interfering with each other, specifically while using a GPS sync feature. This is where LTE is much better as it can support frequency reuse of 1 (aka same channel on every sector). This is really important to carriers who pay millions for their spectrum.

So you'll have 2 sectors operating next to each other and each will have their own channel, so no interference, or will your 2 sectors be back to back and use the same frequency? I read up on the sync stuff before, but don't remember all the details. Is that where all the tower antennas send to all the customer antennas at the same time and then they all sync in sending the response packets back at the same time, so that you don't end up with collisions (or greatly reduce them)?

I imagine there is some latency added with that, but probably works out better than dealing with all the collisions.

How do you deal with non-customers who are in the path of your antennas and have home wifi setups? They get slowed down or have to know to move channels (assuming they aren't set for automatic channel assignment)? And then, for your customers, you tell them which channel(s) to avoid for their home wifi?

[swwifty]

Sorry, I'm not understanding this. If they got 110 Mbps aggregate, and if aggregate the total of the send speed plus the receive speed, when sending and receiving at the same time, then how is it 110 Mbps in one direction when not sending in the other direction at the same time?


Distance was too great, or needed to be pointed better, or the channel was too noisey from other systems around there? Why do you think it wasn't able to hit the higher modulation?


Hey, if they don't have any other way to get internet, then I suppose 10 Mbps would seem pretty darn nice. With just simple math and ignoring possible slowdowns from multiple users hitting it at the same time, and slowdowns from spreading the signal out over a wider beam width with sector antennas, that's 110 users over that 110 Mbps link (or more, depending on your answers about single direction speeds). In a sparsely populated area, that seems like a lot of people!

I agree about the 1 Gbps not being totally necessary. I am looking forward to faster speeds than my 10 Mbps DSL here, with my LTE setup, because:

A) I have multiple people in the house who stream video at the same time. We got rid of our satellite TV service a few years ago and all our TV is through streaming now. Not to mention Youtube use by my kids.
B) It allows for 4K video, which wants about 25 Mbps. I don't have any 4K TVs yet, but I'm sure in the future I will eventually.
C) You can never have enough speed for large things that need to be fully downloaded, like software installation files, software updates, non-streaming video files, tons of digital images (moving stuff around for home movies/photos), etc.

But if people are brand new to the internet, (A) and (B) probably aren't going to matter to them and (C) is more of a unique thing for someone who does a lot of computer work.

In my area, there are others who have access to cable (I don't), so it would be very difficult for me to compete with that if I wanted to set up a WISP. I could compete with the phone company on the DSL no problem, since the speeds are slow and the service is horrible. There might be some more rural areas here where they don't have access to cable. I'll have to ponder that a bit. I do know that I used to check for any WISPs that might have sprung up, every few months, praying that something other than DSL would become available to me. I did that for *years*! So discouraging to have no other options. I'm sure there are others who feel the same way.


So you'll have 2 sectors operating next to each other and each will have their own channel, so no interference, or will your 2 sectors be back to back and use the same frequency? I read up on the sync stuff before, but don't remember all the details. Is that where all the tower antennas send to all the customer antennas at the same time and then they all sync in sending the response packets back at the same time, so that you don't end up with collisions (or greatly reduce them)?

I imagine there is some latency added with that, but probably works out better than dealing with all the collisions.

How do you deal with non-customers who are in the path of your antennas and have home wifi setups? They get slowed down or have to know to move channels (assuming they aren't set for automatic channel assignment)? And then, for your customers, you tell them which channel(s) to avoid for their home wifi?

You can either have 110mbps transmit or receive (but not at the same time.) If you do it at the same "time" and the air time was split 50/50 then you'd have 55mbps transmit and 55mbps receive at the same time. Technically this is not at the same "time" as TDD can only receive or transmit at any given moment. It's just switches so fast between transmit and receive that it looks like its happening at the same time. I hope that makes sense. I'll likely be splitting most of the air time for download, since most users want higher download speeds than upload.

I basically just needed a stronger signal to get higher modulation. Real world though is always very different, so even though you might be getting a strong enough signal for 256 qam doesn't mean you can always hit it. I suspect when I have much higher quality sector antennas, and high gain (25dbi+) CPEs I'll be able to maintain 256 qam.

Users won't all be limited to plans at 10mbp. I'll have a combination of users with 10/25/50mbps download plans on a 20mhz channel. The reality is, most users don't use their max download all the time, so you can get away with this. Realistically each AP will probably have a max of 35ish CPEs connected. It really depends on how busy those users are, but I don't want to get too high in over subscription and cause issues.

I don't think it would be that hard for your to compete with cable. There is DSL companies and Cable companies around here, but they all typically have poor customer service and spotty connectivity.

That's correct on the frequency reuse. GPS sync really doesn't add any over head, it just helps reduce self interference so one can re-use channels.

Interference on the CPE side can be an issue. I'll providing the in house router/AP and will be able to make sure the inside frequencies don't conflict with the CPE outside. Neighbors will be outside of my control though, but a high gain CPE helps reduce any interference and noise. In the screenshots above you can see the noise floor on the station side (which was the simulated CPE in this case) was -97 which is super low. I also used the litebeams a bit on my property to connect my moms house to mine and easily saw a -100dbm noise floor cause homes are so spread out around here. In the city it might be a bit harder to get than, but we should be okay regardless.

[xdavidx]

If you do it at the same "time" and the air time was split 50/50 then you'd have 55mbps transmit and 55mbps receive at the same time.

Okay, I'm clear on what it is now. That's what I thought it was at first.

I'll likely be splitting most of the air time for download, since most users want higher download speeds than upload.

Makes sense. That will decrease latency too, as the TCP ACKs won't need to wait as long for their turn, with the GPS Sync.

Realistically each AP will probably have a max of 35ish CPEs connected. It really depends on how busy those users are, but I don't want to get too high in over subscription and cause issues.

That's still a pretty good number.

I don't think it would be that hard for your to compete with cable. There is DSL companies and Cable companies around here, but they all typically have poor customer service and spotty connectivity.

Cable here starts at 50 Mbps and goes up from there, with 100, 150, 500 and 1000 levels as well. They do have poor customer service and sometimes have technical issues, but for the most part, it just works. The DSL here is 6, 10, or 22, real world speeds. But that's if you are close enough to the central office. A lot of people are sub 1 Mbps, I'm guessing. And I have to believe those people don't have cable as an option, so I probably could do it for those people.

Interference on the CPE side can be an issue. I'll providing the in house router/AP and will be able to make sure the inside frequencies don't conflict with the CPE outside.

Ah, that's cool. Fewer variables to worry about. And if you give them 2.4 GHz and 5.8 GHz on the inside WAP, the 2.4 won't interfere at all and will give them good coverage throughout the house and outside.

Neighbors will be outside of my control though, but a high gain CPE helps reduce any interference and noise. In the screenshots above you can see the noise floor on the station side (which was the simulated CPE in this case) was -97 which is super low. I also used the litebeams a bit on my property to connect my moms house to mine and easily saw a -100dbm noise floor cause homes are so spread out around here. In the city it might be a bit harder to get than, but we should be okay regardless.

Are you saying you'll have higher gain on the receiving end (customer end), so it can reach out to hear the sector antennas, and the non-customer neighbor's won't hear the signal, since you aren't blasting as much from the sector antenna side of the links? I never thought about doing that. Makes sense if you don't need high gain on both ends of the links.

How do these antennas, frequencies and radios handle foliage? Can you go through a bunch of trees at that higher frequency, or does it drastically cut down on distance?

[swwifty]

Are you saying you'll have higher gain on the receiving end (customer end), so it can reach out to hear the sector antennas, and the non-customer neighbor's won't hear the signal, since you aren't blasting as much from the sector antenna side of the links? I never thought about doing that. Makes sense if you don't need high gain on both ends of the links.

How do these antennas, frequencies and radios handle foliage? Can you go through a bunch of trees at that higher frequency, or does it drastically cut down on distance?

A higher gain CPE will help reduce the strength of neighboring wifi AP, even if they are on the same channel. This is because the beam is focused tightly and aimed at the AP on the tower. The sector (AP on the tower) still covers a wide area and could interfere with a neighbors AP if they are using the same channel, but not very likely as the signals are so weak by the time they get inside a home from a AP on a tower.

5ghz doesn't handle foliage very well at all. Essentially all customers on 5ghz frequencies need to be clear line of sight.

[xdavidx]

5ghz doesn't handle foliage very well at all. Essentially all customers on 5ghz frequencies need to be clear line of sight.

That would be my biggest issue here. Relatively flat, but some hills, and no mountains to allow for beaming across open air from high points.

Who puts the antennas on the towers? Do you do that, or do the tower owners require that their people do that?

[swwifty]

That would be my biggest issue here. Relatively flat, but some hills, and no mountains to allow for beaming across open air from high points.

Who puts the antennas on the towers? Do you do that, or do the tower owners require that their people do that?

You'd be surprised, I bet you could find some good spots for APs to cover a big area.

I'll be hiring a company to climb the tower and install equipment that is certified to do so with the tower owners/company.

[xdavidx]

I'll be hiring a company to climb the tower and install equipment that is certified to do so with the tower owners/company.

Do you give them the angles to mount things at, or do you have the antennas pre-angled on a mounting system, or do you do an active test with them up there with them adjusting before they come back down?

[swwifty]

Do you give them the angles to mount things at, or do you have the antennas pre-angled on a mounting system, or do you do an active test with them up there with them adjusting before they come back down?

with the PTMP sector antennas they will just set them at a azimuth and a down tilt.

The backhaul PTP parabolic dishes will have to be actively aimed while someone is on the tower.

[xdavidx]

The backhaul PTP parabolic dishes will have to be actively aimed while someone is on the tower.

So do you take part in that process (telling them where they are at by you using the ubiquiti software), or do they use their own equipment that is locked onto the dishes such that they know the dishes are aimed at each other?

[swwifty]

So do you take part in that process (telling them where they are at by you using the ubiquiti software), or do they use their own equipment that is locked onto the dishes such that they know the dishes are aimed at each other?

I'd be communicating in real time with the guys on the tower. I'd be on the other end of the link adjusting, as the other end of the link in this case will be on the roof of my office.

[xdavidx]

I'd be communicating in real time with the guys on the tower. I'd be on the other end of the link adjusting, as the other end of the link in this case will be on the roof of my office.

Ah, so the office antenna is the first antenna after the fiber comes into the picture?

[swwifty]

Ah, so the office antenna is the first antenna after the fiber comes into the picture?

Yeah, the fiber is connected to the central office, which will have multiple backhaul antennas to multiple different towers on it.

[brad2388]

What state are you in?

We are looking at starting a small wisp. Had more questions.

[swwifty]

Sorry I haven't responded to this thread, been super busy. If I can help answer any questions let me know, for now my WISP project is on hold due to trying to find funding.

[brad2388]

Ah!

Im currently going thru zoning to get our tower. Going to put up a 140’ tower.

Havent decided on equipment but will prolly just do the LTU at the moment.

What state are you in?