Chapter 22 - Is Law Enforcement the Red–Headed Step Child of the Broadband Movement?

When Wireless Broadband was on everyone’s lips 8 years ago, we all thought we would be able to use our laptops everywhere. About the same time that Earthlink and Metro-Fi realized you can’t make “Free” pay off for their investors, 3G started moving in to fill the void. Then YouTube came along, pushed 3G to the ground and said, “I spit in the face of your puny bandwidth (insert Austrian Accent Here).” 3G then said, “Oh yea, my big brother, 4G, is coming and he will take care of you. You will be sorry.” YouTube said, “BTW, meet my cousins, Hulu and NetFlix”. 4G took one look at these guys and said, “I’ll fight you guys but you have to have one hand tied behind your back, both legs tied together, and we are only going to fight for 10 minutes. After that I win and you have to go home”.

In the meantime, the Big Land Barons who wanted to expand their holdings went to the Lords of the FCC and whispered in their ears, “Our lands aren’t big enough and we have rocks and trees in our way. If you kick out the squatters that are on some of your prime land, we will buy it from you and enrich your coffers.” So it was that the Lords of the FCC created The Great Plan. They took The Great Plan to the Council of Kings and said, “We need you to pass a law to kick out the old squatters. We will tell them they are doing the right thing for the country and then resell their land for a fat purse. We will then give some of the land to new squatters for free who will also develop the land and make our Kingdom better.”

When the Sheriffs heard of The Great Plan, they said unto the Lords of the FCC, “We have worked our lands to death and need new lands. The Bandits are smarter, faster, and meaner. We need new lands all across the Kingdom and in every village so Sheriffs are closer and can work together to stop the bandits.” In the Great Plan, the Lords of the FCC decided to appease the Council of Kings and not ask them to use the coin from the Great Sale to pay for the Huts and Barns and lookout towers with 360 degree coverage and an 8” spyglass mounted in the middle. Oh no, they were more clever than that. The thought they could fool the Big Land Barons into paying for the not only the land, but for the huts and barns and lookout towers with 360 degree coverage and an 8” spyglass mounted in the middle (I’m a huge Arlo Guthrie fan). The Lords of the FCC said unto the Sheriffs, “we will grant you new lands in order for you to protect the peasants from the bandits.” Thus, the Lords of the FCC were happy with their new plan and went forth to preach it. And so it was written, and so it was done.

To the peasants, the Lords of the FCC preached, “We are confiscating ill-gotten lands given away by the former Lords of the FCC in order to give you better services and enhance your cities and huts”. Prosperity will grow across thy land and all will be connected to the Great Message.” And the peasants and other squatters did not object for it was not their land being confiscated.

The FCC executed The Great Plan. They confiscated the lands and sold them off to the new Land Barons. The new Land Barons offered the Lords of the FCC a great amount of coin, thus ensuring that the Lesser Land Barons weren’t going to be able to buy the new prime land. At the same time, the FCC told the Sheriff’s, “We have decided that your land is too valuable to just give to you so we are going to sell it to the Big Land Barons. However, we are going to make the Big Land Barons build you houses and barns and lookout towers with 360 degree coverage and an 8” spyglass mounted in the middle.”

When the Land Barons read the scrolls written by the Lords of the FCC on how to use the new lands designated for the Sheriffs, they went to the Lords of the FCC and said, “We do not want that land. It is too costly and cumbersome to build the houses and barns and lookout towers with 360 degree coverage and an 8” spyglass mounted in the middle.” They then paid the Lords of the FCC a great amount of coin for the land they had already bought. The Lords of the FCC quickly left the Great Hall so as to not have to explain to the Sheriffs why their plan had failed and the Sheriffs still had no new land.

After that, many Sheriffs sent many riders to the Lords of the FCC requesting the new land. The Lords of the FCC spent long seasons pontificating on what to do about the land they confiscated for the Sheriffs. After a very long time, they came up with The Little Plan. The Lords of the FCC decided in the Little Plan that they would grant the land directly to the Sheriffs. They said, “We will give you the lands, but we will tell you what you may build on the land. You may only build huts and barns and lookout towers with 360 degree coverage and an 8” spyglass mounted in the middle as to our specification.” The Sheriffs said, “We have no coin to build huts and barns and lookout towers with 360 degree coverage and an 8” spyglass mounted in the middle. Where is the coin from the Land Barons for sale of the other Land?” The Lords of the FCC said, “It has been confiscated by the Council of Kings and redistributed to friends of the Great Messiah and the Council of Kings. There is no coin for you. You have to find your coin from somewhere else to follow the Llittle Plan.” And that my dear friend, brings us to today.

Basically State and Municipal Law Enforcement sort of got left out in the cold when it came to the new 700MHz frequencies. It’s not that they didn’t eventually get the bandwidth they needed; they were told that they must deploy the most expensive technology available to actually use it. Instead of using the money from the auction to build out this infrastructure, each municipality must fund their own infrastructure. Of course, considering that 3 different agencies in the Justice Department haven’t been able to build a simple radio together after wasting hundreds of millions of dollars with no end or product in sight, it’s probably too much to ask them to build a nationwide wireless system. This edict was also given at a time when government budgets are getting hammered from top to bottom. Since public safety has no money to deploy even two tin cans and a kite string, I don’t think we will be seeing high-speed bandwidth for mobile public safety in the near future in most major cities.

We started discussing a project last month where I needed to move 1Gbps or more of bandwidth 20 miles for a county wide system. There is new wideband equipment being released as we speak and I haven’t finished my homework so I’m going to table that phase of the project for a while. Since the project has several components, I thought we might jump over to the third tier, the last mile, since it directly ties into public safety.

As many of you live in areas where your vegetation grows over 8’ and doesn’t make you look like a porcupine when you bump into it, I thought tackling a project like that would be a good idea. Living in the desert has made me oblivious to the fact that there are cities across the country where houses are surrounded by trees that could double as space elevators and should have lights on top to warn airplanes away. Throw in vegetation that comes with its own zip codes, and there are places where the term Non-Line-of-Sight (NLOS) takes on a whole new meaning. Every cell tower that I saw in the area was so tall I figured I was coming down with magic beans if I ever had to climb one. I also learned that approaching someone getting out of a truck that came with a factory gun rack was probably not the best idea.

However, as high as all the cellular towers were around the county, there is no chance that 80% of the houses are ever going to see one from their front window. That means we are left to figure out how to get through the trees. In Chapter 17, we talked about how 900MHz can punch through vegetation, houses, and really mean neighbors. Since that article was written, some of the data I’m reading on current 900MHz deployments is pretty promising. However, deploying 900MHz can be kind of like trying to give a cat a bath, you get a trip to the emergency room and the cat just gets really ticked.

A quick review of 902-928MHz band means that we only have 26MHz of bandwidth to work with. By comparison, 5.8GHz has about 100MHz of spectrum to work with and 2.4GHz has approximately 60MHz. In practical application, a 5.8GHz system can deploy 4-5 APs with non-overlapping 20Mhz channels and a 2.4GHz tower can have 3 non-overlapping 20MHz channels. The 902-928MHz band is a little tighter so we only have room for one channel if we are using a standard 20MHz wide channel.

That means we need a different strategy. Assume that our coverage area is 360 degrees. Most wireless products in 902-928MHz band use down-converted WiFi chipsets. That means the throughput will be the same as 802.11a and 802.11g radios with the same channel widths. Motorola uses an FSK scheme instead of an OFDM modulation scheme that trades off a lower throughput for a better s/n ratio.

Both systems have a bandwidth rate in Mbps that is numerically about ½ the spectrum size. For example, Motorola uses an 8MHz channel and has a maximum capacity of 3.3Mbps total aggregate. WiFi down-converted systems with a 10MHz wide channel will have an aggregate throughput of about 5Mbps. Some Wifi systems have a little higher throughput but all of this assumes a connection at the highest level modulation rate. The other side of this equation is the whereas Motorola will work with a s/n ratio of 3dB, a WiFi system needs a minimum of 10dB.

802.11N 2x2 MIMO has a different formula. Not only is the efficiency of the protocol better than 802.11a/g, the processors are typically faster, more efficient, and have better sensitivity ratings than older a/g chipsets. From there, throw in the fact you are transmitting two signals in the frequency spectrum. The end result is such that the rule of thumb of throughput is approximately quadruple the channel frequency width. A 10MHz channel width should have a theoretical throughput of about 40Mbps.

The lack of channel bandwidth in the 900Mhz band is one reason that it never caught on very well. The other reason is that the noise floor is significantly higher in the 900MHz band than it is for other unlicensed bands. Because of the NLOS nature of the band, it’s heavily used for SCADA, baby monitors, cordless phones, ham operators, and many other things. In any major city or suburb, you probably have noise levels in the 50-60dBi range which makes it very difficult for most WiFi based chipset radios to operate.

The third problem with the 900MHz band is that laying out a network design for a large area is significantly more difficult. In 5.8GHz, the antenna beam patterns are pretty well defined, the signal can’t penetrate lace curtains, and it has limited reflection characteristics compared to the 900MHz. For those reasons, it’s relatively easy to define optimal tower locations. 2.4GHz sort of falls in between but the noise figures for 2.4GHz will still be lower than 900MHz at ground level. At the tower locations, I can imagine it’s a toss-up as to which frequency band will have a higher noise level between 900MHz and 2.4GHz depending on the population density around the tower. 900MHz on the other hand, bounces around like a Superball in bathroom, needs a Fresnel zone the size of Delaware, and just feels a little tickle when busting through a brick wall.

Verizon is probably about halfway to deploying their 700MHz LTE system across the country. The difference between them and us is years of experience in 800MHz and software that costs more than my last car. In addition, the antennas they use can be remotely adjusted on the fly in micro increments to fine-tune coverage zones. Since I haven’t heard anything about WISP operators learning to levitate, that means lifts or tower climbs, both of which are significantly more difficult and time consuming than moving a mouse.

With these issues, why would anyone want to use 900MHz band? Well, that is because we really don’t have much of an option. It’s our only option through Sherwood Forest and we need to figure out how to make that work. Let’s first define the environment as being rural which reduces the variables and takes the noise figure off the table. Then let’s assume we are covering about 2 miles in every direction and we have trees all around. Throw in the decision to limit users to a maximum download speed of 4Mbps and upload of 1Mbps for Round 1 and the system design gets a little easier.

The first issue is the AP configuration. Since 802.11n 2x2 MIMO is pretty much standard in the WiFi industry today, the use of it in 900MHz is unique. The Ubiquiti Rocket M900 with a dual-polarity 13dBi 120 degree sector antenna makes an attractive option. Assuming a 20MHz wide channel, the AP should be able to support a theoretical maximum of 60-100+Mbps of aggregate bandwidth. However, we have to put 3 of them on the tower to cover 360 degrees and I guarantee we aren’t the only squatter on that land. That means that we are going to have to limit the channel size to 5Mbps to avoid overlapping channels and minimize interference. It also means that the maximum theoretical throughput is about 20Mbps and from my testing, I would assume 10Mbps per AP.

If we use the 10-1 client/bandwidth formula, then we should be able to support 20 users per AP with a 4Mbps down and 1Mbps up scheme. That’s also 60Mbps of total capacity per tower. Those aren’t bad numbers if you are charging $40 per month per client. If you are using Water Tanks for example, where you can isolate the antennas from each other, you may have the option of using 10MHz channels. There are also antenna shields from sales@rfarmor.net that promise that you can use 10MHz channels and radios on the same tower and they won’t interfere with each other. However, this could also be accomplished with GPS synchronization with close to similar results if the Rockets every support this feature. I’m a fan of as much isolation as possible with multiple APs on the same tower regardless of synchronization so they are in my budget list.

This is where we tie all this together. 900MHz in rural areas is also a great poor man’s Public Safety System. With the right RF engineering and other design features, the same system could deploy 2-10Mbps or more to a police vehicle. Fast handoff hasn’t been resolved yet but I’m working on a couple solutions as I’ve mentioned in other articles. A system like this should cost about 1/20^th to 1/100^th the cost of an equivalent LTE system. I’m not suggesting that this type of system be deployed in any cities or suburban areas that have high noise issues in that band or that plan on deploying a 900MHz smart grid system, but since over 90% of this country is still rural, this capability can be added for at a cost of under $3000 per AP with each AP covering 4-36 sq miles. The cost for the cars is less than $400 without fast handoff or redundancy. Compare that with a typical LTE or WiMax deployment that the police clearly have no money for, and it’s a pretty good alternative for small towns and rural counties.

900MHz is both magical and a pain to work with. It opens up new opportunities in rural areas where wired fears to tread for financial reasons. At the same time, it’s also a little more expensive than traditional 5.8GHz PTP systems but a lot less expensive than most street level 2.4GHz muni systems. However, when compared to 3G speeds, 5GB caps, spotty coverage, or even worse, no coverage, it’s still a far better option. The application of 802.11n 2x2 MIMO technology now makes it a more viable technology for rural areas.

Chapter 19 – Catch a Wave-Guide and You are Sitting on Top of the World

The Beach Boys are going to hate me for this but I’ve been waiting for years to use that line. I also wanted to title it, “Look Ma, no mesh” but I should have used that one several articles ago. It’s not that I have anything against mesh as there is an application for almost every technology. At this point in the industry and the economy, however, it’s time to get past a word very few non-technical people understand and the excessive associated cost of it. Anyway, this article is about wave-guide antennas so let’s get back to that.

Vivato was a wave-guide based antenna. I have had Securawave wave-guide antennas installed for about 7 years. I became a believer when I connected a car at 2 miles and my laptop inside a Jack-in-the-Box at 1 mile. The horizontal polarity was a huge advantage since most wireless APs were vertical polarity. Securawave is no longer in business so I’m hoarding the last few units I have to support units I have in the field. Not that solid aluminum blocks have a tendency to fail as I suspect they will last longer than the buildings they are mounted to (they just don’t make them like this anymore), but in case of physical damage. I don’t need dual-polarity and 2x2 MIMO yet in these areas because Qwest hasn’t figured out how to get more then 3Mbps over the so-called HD Internet services and I’m not ready to mortgage my house for their other service offerings. Of course it’s hard to dial the phone when your eyes are tearing up from laughter when they advertise their new 40Mbps service. 18 months ago they couldn’t even keep a 640Kbps DSL line running properly in the middle of Phoenix less than 1 mile from Sky Harbor Airport.

Historically, wave guide antennas were expensive to make which is probably why it didn’t have more popularity. Ubiquiti seems to be bringing it back with its new omni-directional dual-polarity antennas. We know that dual-polarity has better penetrating and range capability than single polarity. So the idea of extending that into an omni-directional antenna seems like a great idea. Since there isn’t any other 2x2 MIMO omni-directional dual-polarity antennas that I know about, this is really cool from a technical, design, and financial standpoint. It’s also how we are going to keep Guerilla WiFi cost-effective and make it better.

The new Ubiquiti omni-directional antenna isn’t a true wave-guide antenna. Since it needs both polarities, half the antenna is basically two 180 degree vertical polarity sector antennas back to back with dual 180 degree wave guide antennas. Since it’s not out yet, I haven’t tested the unit but the pre-spec guess is it’s around 12-13dbi. That means the effective LOS range with dual polarity is going to be about 30% farther than an omni with 15dBi of gain for a couple of reasons. However, real world performance is going to be significantly better since dual-polarity will definitely penetrate vegetation better, reduce noise off-polarity, and reduce fading. If the client is using a dual-polarity indoor radio, then not only will range be better, noise will be significantly reduced even further. I smell a huge performance improvement in the air for Guerilla WiFi.

Let’s go back to Chapter 1 of Tales where we designed a $10K per square mile system. In that design, we used a 15dBi omni-directional antenna with a single polarity omni-directional. This design was using a single stream 802.11 b/g/n design. With the new dual-polarity omni-directional antenna, we still use a single radio for our AP but we have doubled the throughput with a 2x2 MIMO stream. In addition, we have doubled the throughput of every hop and added an additional hop. Even at the 4rd hop we are still delivering up to 10Mbps. Keep in mind that at a 10-1 oversell rate, that means that you can sell twenty clients 5Mbps at the end of the chain. Although pricing hasn’t been released, I’m pretty sure this antenna with a Rocket M2 radio will still cost less than $300. Double the performance of the original Guerilla WiFi at no additional cost and it’s better than triple coupon day at my local grocery.

Think about that for a moment. If we only had one egress point for our network, our base network was limited to 3 hops with the same capacity at the end. This single antenna, which allows us to change from a single stream 802.11b/g/n radio to a 2x2 AP, doubles that throughput, thus extending our single AP model out even further and doubling bandwidth down the chain. Our egress point can also use multiple radios which can triple the throughput to 3 times that for $300-$600 more without even getting into out next topic, GPS Synchronization. So for less than $11K per square mile, the system now supports 180-300Mbps, depending on the clients. So if your town is 20 square mile and this whole system cost $250K to put in, then it’s a no-brainer simply for cameras, security, mobile access, and department efficiency. Of course, if it goes through federal funding, has government engineers add in the fact that it has to support mesh (pointless in this and most designs but adds significant costs), throws in ridiculous temperature requirements like -30C for Phoenix or 80 degrees centigrade when -75 degrees centigrade would work fine, and requires copious amounts of paperwork to tell 14 different government agencies that you are paying wages equal to union scale even though you pay your guys more than that, then it’s going to cost $1,000,000 (my English teachers just had heart attacks over that sentence). If you can sense my frustration with federal rules that require union contractor shops to do work that is clearly better suited to IT companies, then you are very astute. This is why projects involving the government cost so much and take so long.

If this is a for profit network, $250,000 to cover 20 square miles with this level of bandwidth is pretty impressive. It’s fairly easy and cheap to add 100Mbps backhaul to each square mile for a total of 2GBps for the entire system. Realistically, I would guess that you would get about 500Mbps before the price starts going up for full-duplex links. Keep in mind that we are back to the core idea of an inexpensive municipal deployment.

Using numbers from previous articles, let’s assume 800 potential clients per square mile. If we get 10% of that base at $30 per month, that’s $48,000 per month. With this type of system, only a very small percentage of clients are going to need truck rolls. Total revenue on this network is almost $600K per year. If users have to get client radios, then they start at $30 for 802.11n 1x1 Vertical Polarity CPE’s. For about $80, you can include a window mount and get 2x2 MIMO. In most environments, I would be surprised if truck rolls needed to be done on more than 10% of the clients. Even if you add in the cost of the client radios, this system should be cash flow positive at 800 clients and should pay for itself at 2400 clients within 12 months. This just covers residential and doesn’t even get into business revenue. The numbers are now speaking to me so it’s time to kick the venture capital market back into high gear.

Also consider this, the 16 AP per square mile strategy now covers a higher percentage of deployments, especially profit oriented ones. If you live in the middle of high-density city, then you would want more APs per square mile for density or you fall back on the super AP concept described in previous articles. Since WiFi is far more unpredictable that PTP RF modeling, there is nothing wrong with installing 16 AP’s and then site surveying to see if there are coverage gaps than hinder more revenue.

Cell phone companies don’t cover every square inch of every house on the planet. It’s not cost effective. They deploy with the best models they have and then decide if it’s profitable after field testing to fix poor signal areas. WiFi should be deployed the same way. Put up 16 AP’s, field test, check the areas with poor coverage, and then decide if it’s worth another $300 in equipment to cover that area. If an area has higher usage, add in a triple radio AP upgrade for a few hundred dollars more. If an area really just needs more signal gain, look at adding a beam-forming AP just for a specific direction. There are many options but all of them would be based on sound profitability principals. There is nothing wrong with walking away from 2 customers that might cost $3000 to add additional infrastructure to cover.

I have 2 “Peeves of week” I have to get off my chest. The second is 99.999% uptime. I was asked to design a system where I have to guarantee the CPE’s have 99.999% uptime. Since the wireless industry has new equipment out every few months, very little of what I would deploy today has enough history for me to put my reputation behind that request. I’m not talking about PTP full-duplex $10K and put links but $50-$400 CPE’s. First off, anything less than 802.11N is too old and too slow for this type of video application. Second, anything that’s 802.11N hasn’t been around long enough to know how it’s going to run 3 years from now. It’s kind of a catch-22 situation. That means using cameras with built-in recorders that are going to cost three times as much or more than using lower priced cameras with CPE’s. Unfortunately there is no product history out there than guarantees that. The reality is that all the radios I work with rarely, if ever, just simply go offline if installed correctly. That doesn’t mean that they aren’t going to down for planned firmware upgrades or other system changes. However, the 99.999% uptime request didn’t stipulate whether planned maintenance was included.

I’ve already mentioned my first pet peeve, municipal bids that ask for mesh when every AP connected has a directional antenna. To everyone who keeps adding this expensive request into these bids, it’s a waste of money taxpayers’ money and costs the city a lot more to support in the long run. When you add a directional antenna to an AP or CPE, it’s a PTP or PTMP design, regardless of what firmware is on there. There is no mesh because the radio can’t connect to anything it’s not pointed at. By adding the mesh requirement, you are either getting the most expensive product out there or White Box APs with custom open-source mesh firmware that is cheaper. I’m not saying there isn’t a place for mesh, but don’t eliminate other options like WDS. It’s not your money you are spending; it’s ours, the taxpayers. Let the industry and a wireless engineer decide what the best product for the design is. It shouldn’t be the salesperson that took you out to lunch last week and has shiny brochures. If mesh is appropriate and the best fit, let the companies bidding on the project put that down. If WDS will work just as well or a PTMP design is better, they will bid that. So can anyone guessed what crossed my desk again this week? I know I’m beating my head against the wall on this since arguing with government is like trying to tell a 3 year old that candy isn’t good for them.

So we have come full circle on Guerilla WiFi from $10K per square mile to $50K per square mile and now back to $10K per square mile with double the performance. If this doesn’t kick the industry back into high gear, I’m not sure what will. Next we will cover GPS sync and how that affects deployments strategies.

Chapter 18 - Demystifying Beam-Forming

Based on some of the emails I’m getting, the biggest complaint is not enough details and without them, it’s difficult to implement the idea. Fair enough, I’m definitely guilty of that. In my defense, please understand that I want to have a personal life. Not that I have one now, as most WISP’s can attest, but if I had to put down every single detail on every single project or idea, I would be writing from here to Kingdom come. Except for the 6 guys on the planet like me that think they ought to make a movie out of every article in EETimes (I think a lower noise figure on a 741 OP-Amp makes a compelling plot line), most of you would be cancelling your Ambien prescriptions. The reality is that the details only matter to technical people and those are called White Papers. I’ve written a couple but I can’t sit still long enough to finish dinner, let alone do a 20 page technical document. My wife says that if I had put as much time into my homework as I have these articles, I would have my Master Degree by now. Of course, if University of Phoenix gave me real life credit for standing in a man-lift hanging antennas 80 feet in the air, I could get my Doctorate without ever attending class.

Let’s get back to the really cool stuff like beam-forming. We covered 900MHz and both the positive and negative aspects. Let’s move on to the category of what’s old is now new again, beam-forming. Vivato pioneered the idea several years ago but the financial model, coupled with irresponsible pre-marketing, didn’t really work in the real world. However, they did get the FCC to change the rules which is going to be a very good thing moving forward. The difference is how the different implementations of beam-forming are implemented and the effect in the real world, technically and financially.

Long before Vivato, the Super Scanner antenna from Antenna specialist tried to get an antenna to function in both a directional and omni-directional mode with the turn of a knob. Some of the manufacturers such as Wavion and Netronics sort of copied this model by using a ring of vertical omni-directional antennas. They can get up to 12dBi of antenna gain off of 7-9dBi antennas. Currently these units are limited to 802.11b/g bands and vertical polarity.

The next kind of design was done by SkyPilot where they simply rotated connection to one of 8 integrated sector antennas at any one time. This gave them up to 44dBm of EIRP in the 4.9-6.0 GHz bands. Ruckus, Netgear (with Ruckus helping), Cisco, and others are now integrating the antennas on circuit boards but at a lower gain. There will be several antennas cut into the boards or some other internal antenna hardware to add vertical and/or dual-polarity to the board that provide directional coverage. These designs are achieving up to 10dBi in gain with the bigger advantage being the noise reduction from other directions. They use the model of picking the 2 best signal antennas to receive the signal simultaneously since doubling antenna capture area provides up to a 3dB increase.

Vivato is still the technical King here in this realm though, although they weren’t covering 360 degrees. Vivato achieved 24dBi of gain in a 100 degree pattern in 2.4GHz. The catch is they did it for $8,000-$15,000, which meant I could either buy a new van for my company or 2 APs. That sort of limited the market for the product to the point that they are no longer in business, which is also what happens when you don’t listen to your vendors trying to sell the equipment. However, that 24dBi of gain is a huge advantage for reaching underpowered smartphones. Since Ubiquiti has now announced that they are releasing a beam-forming product over the next 2-4 months, the question is, does that have value for a municipal design?

Getting back to today, Wavion’s newest product, the WBS-2400 is probably the closest to the Ubiquiti beam-forming radio. It’s also very similar to Altai A8-Ei product with multiple radios, sectored antennas, and one enclosure. Both products tighten up the beam and assign a single radio per antenna. Unfortunately, both these products are still b/g.

Going back to the formula that distance doubles for every 6dBi of gain, if a 2.4GHz beam-forming AP has 21dBi of gain, or what I’m guessing the new Ubiquiti units are going to be, that almost quadruples the range of most omni-directional AP’s. Throw in the fact that noise will be reduced by at least -20dB, and the s/n ratio goes berserk. The effective range increase, and this is only my best estimate in the worst scenarios, is probably a factor of 8-16 in open air environments. This means hitting a smartphone at 3000-4000 feet or more is possible.

Here is where it gets interesting though. Based on past experience, I’m guessing the Ubiquiti beam-forming AP will be less than $300. That is 10 times less than other beam-forming products, none of which support 802.11N 2x2 MIMO. Heck, it’s less than I paid for a baseball bat last season.

We were all trained to think in terms of APs needing to cover 360 degrees for municipal deployments. Every product out there is designed for that. The end result of this is when the density reaches a certain level, the self-interference is basically self-defeating. I’ve seen proposals that suggest 60 APs per square mile for example. Central management systems can dynamically adjust power output between APs to reduce the interference and can simultaneously adjust power output on a per packet basis to reduce the interference even further. However, all this costs which effectively drives the price up to $150,000 per square mile or more for this level of performance. However, what in the playbook says that every AP has to have omni-directional coverage?

Throughout this series, we’ve been driving towards a low-cost, high-capacity design that can be commercially deployed. The original idea was trying to develop an inexpensive Super AP. I’ve gone from $200 to $2000 and was working on an idea that would have driven the cost to a retail level of $4000. It supported 1Gbps per AP and 700+ simultaneous clients, but still it got away from my original idea which was to lower the bar on the per mile cost, which it didn’t accomplish. It basically comes down to the following, are you trying to compete with cable which can deliver up to 50Mbps or delivering Internet to people who have to suffer with dial-up, or worse, DSL delivered by Qwest in Arizona (okay, bad joke).

Beam-forming lets us start with a new playbook. The first thing you do in a playbook is define your assets (okay, I never played organized football so I’m making this part up.). Using the Ubiquiti beam-forming product (2.4GHz version), we know roughly that we will have about 21dBi of gain, 90 degree coverage zone, 16 degree beam pattern, GPS synchronization, and 2x2 dual-polarity 802.11N MIMO. Since we can now hit a phone at 2500 feet without much of a problem in open air, the design mentality changes. Even with 21dBm of gain, we still aren’t going to penetrate several buildings. However, we probably bought ourselves another house or two. By changing the angle of transmission, ala cell towers, and to be fair to Vivato’s deployment design in Spokane, tops of buildings aiming down, and all of a sudden we are hitting several houses down the street. Throw in 2x2 MIMO dual-polarity, and the connection distance goes way up.

Because of the price point, I’m guessing Ubiquiti’s product uses the same type of design as SkyPilot in terms of switching between multiple feed points on the antenna. The difference is that each feed generates a different angle of radiation versus being a completely separate physical antenna. Ruckus hits multiple feeds also with circuit board based antennas.

Although the tops of buildings aren’t ideal for sector antennas due to amount of AP’s that are going to get picked up, if you aim it towards the horizon, angle it down 60 degrees or more, you still get coverage down the street and pretty impressive building coverage. At that angle, you are reducing attenuation from outer wall penetration and even taking the route of shooting through the roof. This doesn’t work all that well in areas with trees, but if the buildings are made out of concrete, brick, or stucco, then this might be the best option. There are a lot of cities where the street lights are decorative and there is no way to install an AP down at ground level, so secondary options are a must. Beam-forming makes this design more useable by effectively reducing the beam pattern down way down.

This model might work in a different way also. Think in terms of 3 dimensions instead of 2. Larger buildings or apartments in downtown areas might be 10 floors or more. Placing these antennas on the side of one building several stories up and aiming into another building let’s you build a vertical WiFi Although attenuation has been a killer, 21dB of gain makes up for a lot of wall and window attenuation. In addition, dual polarity will improve penetration even further. If you pick up 30 customers in a building at $20 per month, 3-4 antennas pointing into the building get paid for in a couple of months. I would have also said it’s significantly cheaper than AP’s in the building until I saw another product that I’m testing (to be discussed later). However, when you add in the savings on pulling cable, it’s a no-brainer.

Irregular areas with streets curving all over the place are another option for this type of design. Intermixed homes and small business areas with mostly 1-2 story homes and 2-5 story buildings work well for this design. Outdoor coverage is universal with indoor coverage hitting around 80% or more with careful planning. Keep in mind I’m assuming everyone wants to give you free vertical assets to enhance the system.

Bringing us back to earth gives us most of the real-world deployments, street lights. This is where the GPS synchronization really kicks in and is now the direct comparison to Wavion or Ruckus. Placement of four of these radios on a pole to cover 360 degrees provides the absolute farthest range of any AP on the market. This is only possible with GPS synchronization to keep them from interfering with each other. It effectively provides twenty four 16 degree beams shooting out in 360 degree pattern. The cost of this super AP will be about $1500 which isn’t a lot less than Wavion or other beam-forming 360 degree APs. It does have significantly longer range through, by a factor of 9dBi and dual-polarity which is worth another 3dB in my field testing. With the IPad supporting 802.11n and the Beam-Forming antenna supporting dual-polarity, this would be a potent combination for off-loading some bandwidth.

If we duplicate this design with Altai or Ruckus, the cost is now over $10K per AP. There are other manufacturers such as Motorola that use sector antennas but then the antenna gain drops back to 12dBi or less and their beam patterns are 120 degrees. The best way to reduce noise is to decrease the beam pattern which it also doesn’t do. Effectively we get a 9dBi increase and 20+dB of noise reduction for a cumulative 29dBm improvement in s/n ratio. Regardless of what wireless philosophy you follow, that’s huge.

Here is one of my philosophies though, “If you spend too much, all you have lost is a little money. If you spend too little, you could lose everything.” Guerilla WiFi is based on the concept of being the most cost-effective way to deploy and what I feel is the only way to make municipal wireless a self-sustaining profitable model. That doesn’t mean it’s the best way in every situation. I’m describing equipment that isn’t even out on the market yet and isn’t field tested. Wavion, Ruckus, Altai, Bel-Air, Motorola, FireTide, Cisco, Enterasys, and a host of other vendors are proven products that have been deployed and tested. I do think these vendors are making it difficult to meet the financial needs of a profitable municipality model which is where Guerilla WiFi comes in, but the products are solid. This models works for me and others who are willing to spend the time to work through early firmware issues and fine-tune the models during deployment. It’s kind of like the difference between Linux and Windows. Since Ubiquiti uses a common firmware platform across all of their outdoor products and has made great strides towards stability and features, I expect the new products to use the same firmware base which means , the firmware. However, there is still a long way to go towards a turn-key municipal deployment without a lot of engineering intervention. Based on the cost/performance ratio, I believe it’s worth it. But realistically I spend a lot of time testing and adjusting. Most customers are going to expect a more turn-key solution. However, if it’s your money, then this solution provides the best chance of financial success.

With this AP design, $1500 per AP is getting pretty pricey. However, it will also combine with our next article, the 360 degree dual-polarity 2x2 MIMO AP for under what I’m guessing is going to be $300. I’ll try not to wait 3 weeks to make this happen.

One other note that I want to mention is that Mike Ford is no longer at Ubiquiti. Mike was a central figure that seemed to have his hands in everything from testing to customer support. Over the last 3 years, he has become a friend that always went the extra mile to make sure I had the resources I needed for my clients. He was also instrumental in some of my decisions on my deployments. Although I don’t know his future plans, I am very sorry to see him go.

Chapter 17 - Who needs White Space?

It’s time to step up our game. There is no problem generating massive bandwidth from an AP location. We have proven that fact. What we haven’t figured out yet is how to leap tall trees in a single bound or walk through brick walls. If you are willing to add in another 20Mhz of super-powerful, wall-penetrating, obstruction busting, tree smashing signal, then we have solved the problem.

You are thinking I’m going to jump on the White Space bandwagon. I’m sure I will someday but there’s a lot of work that has to happen before that option is available. However, the infrastructure we have designed is pretty flexible and inexpensive. When White Space becomes feasible and cheap (my favorite word), we can add it. In the meantime, we have two other options. I think I will save the best for last though.

White Space is touted for 2 reasons, extended range and building penetration. It also has one big disadvantage. In major cities, there may not be a lot of channels available according to Spectrum Bridge, for White Space to operate. In addition, limited power output from clients is still going to limit high-bandwidth range back to the AP. I also see the 6MHz channels being an issue with bonding being the same problem as trying to run 40MHz outdoors.

Before we jump into this though, let me make note that Ubiquiti just released a stack of new products that are game changers in WiFi, indoor and outdoor, Video Surveillance, and cellular service. These technologies cover everything from Beam-Forming to GPS sync to dual-polarity omni’s. I’ve had to hold back due to NDA’s but we will now start covering how these technologies can be integrated into our Guerilla WiFi design to take the systems to a whole new level. Most of these products are several weeks away from shipping so we have time to develop our system. I do a have a pair of the 900MHz M series 802.11N 2x2 MIMO AP’s in my hands and that is the topic of this article.

Option one is 900MHz. Yes, it’s crowded, noisy, and seriously overused. So is a Japanese subway but people still use it because it’s the best option. Until now though, the best WISPs systems limited users to about 3Mbps under ideal conditions with APs limited to about 7Mbps. There really wasn’t a lot of development in that frequency band due to the interference and reduced band size as compared to all the other unlicensed options.

900MHz has close to the broadcast properties as White Space except for the vastly higher interference. In a municipal system with 16 AP’s per square mile, AP’s are within 600’ so range of everybody. Unfortunately, 2.4GHz can’t penetrate obstructions very well. Brick or Stucco buildings that will suck the life out of 2.4GHz are merely a few dB of loss to a 900MHz signal. At that range, trees effectively disappear. Junior’s frequency hopping baby monitor and the SCADA transmitter hanging on your water meter is now more of a problem than obstructions. In 900Mhz, with 802.11N 2x2 MIMO now being applied, bandwidth isn’t the issue any longer. The biggest problem is interference.

Everything has a threshold though and you just have to find it. With parents, it’s how low your grades can go before you become the prisoner of the bedroom Alcatraz and your friends start filing missing person’s reports. With RF, it’s the difference between the signal and the noise and how efficiently we use the bandwidth. Now toss in a very narrow band, 26MHz, and the total bandwidth throughput from any AP is going to be limited. Oh, yea, did I mention that we only have to go 600 feet?

802.11N isn’t just for 2.4GHz and 5.8GHz. It just hadn’t been applied before in the 900MHz band. Ubiquiti just released several new 900MHz products with 802.11N 2x2 MIMO protocol. Using a 5MHz channel will allow up to 4 APs to operate on one pole, which each one providing up to 20Mbps. However, using buildings and some shielding, might allow up to 4 channels of 10-20MHz in more remote areas to allow up to 300Mbps. I’m sort of guessing here but when I get one of the base station sector antennas in, I will do some testing to determine what would be needed for isolation.

Keep in mind through all of this that we are still dealing with an AP/sector antenna combination that cost less than $500. If budget is an issue and the city thinks that a several 4’ antennas on a pole aren’t their idea of aesthetically pleasing, then look at using 4 of the Nanostation M900 Loco’s. They are very small, and although rated at a 60 degree beam pattern, they can easily cover 90 degrees with a small drop off in antenna gain. In fact, the beam pattern for these radios is way over 90 degrees at 7.5dBi of gain.

The only problem here is that you need one of these radios in or on the house since there is no portable device that can support 900MHz. That starts getting expensive at $200 for the radio and another $50-$150 for an indoor WiFi device for wireless coverage. However, the problem of building penetration is completely solved.

If I haven’t mentioned it before, we only have to go 600’ from an AP location if we have 16 poles per square mile. Realistically though, if we have 16 APs per square mile, I would probably only use a maximum of 4 AP locations with the 900MHz radios for budget reasons. That means we might have to go 1300’. Of course, we are using a proprietary polling scheme and a dual-polarity signal to go that far. If the noise floor starts at -65, the signal level needs to be at -55 or better. At 1300’, even with obstructions, our signal level should easily exceed that.

Trilliant and other Smart Grid companies are releasing MOAB (Mother of All Bombs) 900MHz radios that are up to 1W for residential installations. If you think that a few towers can cause interference, try fighting tens of thousands of radios dropped into the middle of your coverage zones. Motorola 900MHz WISPS from here to Canada are getting hammered and there isn’t a lot they could do about it. There are going to be cities where running 900MHz WiFi may not be feasible. Don’t panic yet, we will take our 2.4GHz game up a notch also.

There are two advantages to the Ubiquiti 900MHz radios to fight interference. One is the dual-polarity MIMO design. In the city though, most radios are using antennas with such low gain, polarity isn’t going to make a lot of difference. However, the M900 product line came out simultaneously with the ability to frequency hop. That means you have 4, 5MHz channels to jump around with at 300ms rates to avoid noise try and punch a signal through. If the Smart Grid density is too high, then even that isn’t going to matter but right now it’s the best option available.

The second advantage is AirMax. AirMax will simply ignore other packets in the band and also eliminate the hidden node problem. Although interference is interference, AirMax AP’s won’t slow down acknowledging other APs in the band.

Ahh, but what works for city folk works even better for country folk. The dreaded trees of death for 2.4GHz and 5.8GHz are merely pin pricks to 900MHz. Toss in the dual-polarity 2x2 MIMO design and now signal will punch through the forests like Ray Lewis through an NFL helmet. Expand out the channel to 10 or even 20MHz, and throughput for a single AP could go as high as 80Mbps.

On the muni-wireless issue, we can assume that designating 4 AP sites per square mile will add about $1000 or about $4000 per square mile. It also adds 320Mbps of total capacity per square mile. Add in the CPE Capex of $200 per client, assume 25 clients need this radio to avoid a truck roll, and you have an additional $5000. If you truck roll, add another $3750 in the Capex column for those of you keeping track.

Based on those numbers with a $30 per month fee and a free install, it will take 17 months to recoup the Capex. Of course, we want to charge $100-$200 for an install to offset some of those costs. In areas where municipal staff thinks antennas are cool and interference is minimal, we could even use four 900MHz dual-polarity sector antennas with 13dBi of gain. That will provide over 6 times the coverage area which might reduce the AP locations from 4 to 2 but it will more than double the cost per AP, which is a wash. There will be scenarios where either option will be more appropriate.

Our second option is the new beam-forming radios. I’ll cover that in more detail in the future. Since the 2.4GHz versions of these units won’t be out for another 4 months or so, there is no hurry. However, they add another 4-6dBi of gain over a sector antenna and 8-9dB of antenna gain over any other beam-forming AP other than Vivato. Add in dual-polarity, which my field testing shows to be worth up to 3dBi more useable gain, and a 16 degree beam pattern to reduce noise (I’m extrapolating from the 5.8GHz beam-forming unit that was announced. The final specs may vary.) and that that’s enough gain to penetrate an extra wall or almost quadruple the coverage distance to a client. I’ll go into the difference between between all the beam-forming units on the market in our next article.

Now we have even more tools to play with for Guerilla WiFi. Theoretically, it wouldn’t be hard to build a 1Gbps AP to work across multiple frequencies with beam-forming and GPs for less than $4000. Taking this concept even further, it also wouldn’t be hard to create a load-balanced, business quality, multi-frequency design that could bond these frequencies together for very high-capacity throughput. There are other variations of this for backhaul, redundancy, and uptime. It’s possible, with a little networking work, to create a mission critical design capable of delivering tens or hundreds of MB’s to a CPE for less than $400 on the CPE side. This type of system could easily deliver 99.999% uptime using unlicensed frequencies, even with scheduled maintenance. And don’t get me started on 900MHz mobile options. The hits just keep on coming.

Chapter 14 - Money Talks

I have gotten calls from many people that want to start a WISP company, whether using a mesh/muni model or a PTMP system. Although I believe there is no better time than now, that doesn’t mean it’s easy but I hope to prove that it’s financially feasible everywhere. Competing against satellite or cellular services like EVDO, WiMax, or even LTE is a no-brainer in areas that have no wireline services. I’ll cover the new Sprint/Clearwire LTE service just announced for Phoenix in another article. I can build small, profitable financial models all day that can provide superior services even at subscriber/bandwidth models of 10-1. There are also other services like VoIP that can be provided but for the beginning of this analysis, we are going to focus on Internet services only. However, let’s take this into the professional corporate/investor level and see what happens.

Breaking this down into 3 areas and 2 types of design models to cover areas. These areas are a gross oversimplification because each area has different RF models that also have to be considered based on how RF friendly they are. However, for the sake of argument, let’s use these numbers:

1. 
   
   Rural – 20 or less potential subscribers per square mile
2. 
   
   Suburb – 600 potential subscribers per square mile (2700 people per square mile in Phoenix)
3. 
   
   City – 3,000 plus potential subscribers per square mile (Boston 12000 people per square mile)

The 2 basic types of models are PTMP and WiFi. So, let’s look at how each of these models can be deployed profitably. We covered inexpensive WiFi systems early on and I still stand by that model, but let’s analyze it a little more critically and see where it fits in the big picture. More important than anything, is it possible to build a system that has the financial strength to be a growing and profitable company versus Joe Technical’s weekend hobby?

As many WISPs have successfully demonstrated, clearly it’s possible to be profitable if you market in some rural areas. Assuming a starting company of 4 people, the revenue generated has to be around $40,000 per month to be profitable at the low end. I’m just summarizing some of the spreadsheets that I have used so you will have to take my word on the cost structure. With an average monthly rate of $30 per month per client, we calculate that it will take 1333 clients to make that type of revenue each month. By all accounts, that’s a pretty impressive size to jump right into. Keep in mind this doesn’t include your original Capex and how much investment you need to get to 1333 clients. It’s not going to be cheap.

If you are a hot-spot provider, you get revenue from hourly, daily, and weekly rates. Those markets are also shrinking in the U.S. for the most part but some new ideas for phone users are coming forth. In this discussion, we are going to focus on the monthly subscribers. There are also other revenue sources such as installation revenue, business rates that are higher than personal subscriber rates, and other normal ISP types of services. Additional services might require additional staff with more expertise, thus raising the associated monthly costs.

Rural markets are easy. Set up a PTMP system on whatever inexpensive vertical assets you can get access to. If there is not a lot of vegetation, these systems can handle36 square miles easily per tower and up to 300+ users per tower. This assumes you don’t already have competition in the area and there is no interference. You just need 7 towers with 200 users on each tower cover your monthly expenses and be profitable. If there are any of these areas left in the U.S., let me know but I’m not going to hold my breath.

However, there are some rural markets that are underserved simply because of distance, vegetation, and costs of deployment. They may not have 1300 clients, but find a few of them with a couple hundred clients per area and the plan still works. Some of these areas were just not reasonable to do with 2.4GHz or 5.8GHz. They may have been a good 900MHz radio option but limits in equipment, the band, and interference mean that most of the 900MHz products either only delivered 1.5Mbps or the cost of deployment was too high. Newer 802.11N 2x2 MIMO equipment that is hitting the market now should allow for an improvement in throughput in these areas with client bandwidth similar to anything available in the 2.4 and 5.8GHz bands and cost far less. Depending on the design, it should be reasonably easy to promise 10Mbps to a client on the wireless link depending on back end bandwidth. 900Mhz isn’t an ideal band due to limited spectrum width and interference in city or even suburban deployments. However, it extends out the range of clients in dense vegetation areas. In most rural deployments without too much interference, I would expect bandwidth off a centralized tower to max out around 160Mbps with the right setup in 900MHz.

Let’s move into the suburbs now. Most suburbs are served by cable, DSL, or a combination of both. To be honest, DSL is simply not living up to the hype of the marketing division. In Phoenix, Qwest advertises speeds up to 20Mbps when they are lucky to hit 3Mbps, even within 1 mile of Sky Harbor Airport in the middle of the city. Move 300 feet and not only can they barely deliver 640Kbps, they can’t keep it running more than a month or two before it to crashes again. In my case, after I complained for the umpteenth time, they told me with one more complaint they would pull out of our business complex leaving me with no wireline high-speed bandwidth. I had to move my office just to get 3Mbps after several years of subpar service. Even if you are satisfied with your DSL service, it only takes one bad technician adding one more client in your area to cause it slow down or crash again. If this is the main provider of service in your area, I say let the best technology win. I will take WiFi based wireless over any area where DSL is the only technology available. That alone means that major cities still have opportunities.

Cable is another matter. Cable companies are promising huge amounts of bandwidth today and for the most part are very technically stable. In Phoenix, I have a 20Mbps circuit. However, I get around 11Mbps on Speedtest or Speakeasy most of the time. Other times I have seen it down to 1Mbps. Even though you may pay for a specific level of bandwidth, there is no SLA that you will be delivered that level as opposed to a business level SLA agreement. The reality is that the bandwidth advertised is the burst speed or web browsing speed. If you download or try to move large files such as video or a file transfer, that speed will be reduced significantly. However, other than fiber to my house which I doubt I will see in my lifetime, it’s the usually the fastest option.

In either case, this isn’t a market where 1Mbps is going to fly. Even Grandma and Grandpa are watching NetFlix. Google TV is no longer an urban legend either. Throw in every game machine out there downloading movies and unless you are willing to run with the big dogs, this is not a battle ground you want to enter. I’m talking about a wireless service where you plan in advance on delivering 5Mbps average to everyone with peaks up to 50Mbps or more and no more than an 8-1 bandwidth to user ration. 802.11 b/g/a won’t fly here. You have to be ready to invest in bringing a large bandwidth pipe in and the subsequent costs of deploying 1333 users. I have numbers on both PTMP and Muni-WiFi models but to simplify this model and since the area is generic, let’s assume a 50-50 model.

Since we are estimating 600 households per square mile (houses and multi-dwelling unit) and assuming we get 20% of that market, we need about 10 square miles to meet our $40,000 revenue total. That also means we need about 4 towers or building assets to ensure we have LOS to all the locations. Estimating a cost of $25K for the backhaul (assuming the entire system is wireless) gives you 2Gbps. However, it might make more sense for a local fiber, MPLS, or even cable backhaul although using a company for your backhaul that you plan on competing against may not be the best idea. Unless you consider bringing an anti-trust lawsuit against multiple telcom providers while they drive you out of business a fun time, you probably want to find other local carriers. In the end, we have determined that the tower installations will cost about $125,000.

Since half the clients are WiFi, we are still going to have to install 16 APs or more per square mile. I’m going to use that number along with some numbers on designs I’m working on now to come up with $30,000K and 360Mbps per square mile. Each AP will deliver up to 100Mbps to start with and if you go back to previous articles, can deliver several hundred Mbps if needed. Since we have the vertical assets, backhaul to the street lights is taken care of. The problem here is that it still costs us $300,000K and is the largest part of the Capex. Additional revenue sources have to be found here to justify this but we will discuss this later.

Our numbers assume that half of the clients will require truck rolls. That will cost $195,000 to deploy. Considering that each technician can do about 4 installations a day, it will take 160 man days to install enough clients. Since there is only about 20 workdays per month, it will take 8 crews to get up to this number within a month. Most of us would have to outsource this unless you have several friends with days off who also happen to work as installers for Direct TV. The revenue on installations will range from $0 to $200 depending on the market. Assume $100 and the net cost of deployment is going to run about $60K.

The other 650 clients can be installed any time since they are WiFi based. Either they can connect directly or some type of CPE device can be made available. Let’s call that a no Capex cost since $50 will come pretty close to the actual cost.

To summarize, the Capex for this model costs $530,000 to deploy. Even if we net $10K per month which is reasonable, this isn’t going to fly financially with a 4.5-year ROI. This is also a maximum bandwidth system than can compete directly with Cable/DSL/LTE or anything else out there for the near future. Scaling it out further doesn’t improve the ROI but it sure increases the revenue stream. So, how can we make it more cost effective? There are two ways, reduce the cost or find more revenue.

Start with the idea that we only need 100Mbps per square mile in the beginning. This reduces tower costs down to $15K per square mile for a backhaul system that will support 720Mbps instead of 2Gbps. We just saved $75K. It also drops the per mile costs of the WiFi system to about $20K per square mile. That’s another $100K on the savings side.

There isn’t much that can be done on the truck rolls other than to consider the option of doing the installations in house. That saves about $50 per installation but it may take 3-6 months to get up to 650 installations. That’s also more reasonable in most models that I have developed. What I didn’t take into account is the advertising necessary for this speed of penetration but there are several cost-effective ways to do this. I’m leaving this number alone for that reason.

The cost is now down to $360K. The ROI is down to 3 years but is still not that reasonable except for this, cable companies are not reducing their rates. In fact, they keep going up along with the bandwidth. One of the reasons is that they are being squeezed on the TV side by content providers demanding more revenue per users. At the same time, it’s much more difficult to raise TV cable rates due to competition from satellite providers and local ordinances. People are also dropping land lines faster than a Bugatti Veyron because of cellular phones. As much as I complain about cruddy DSL service, the reality is that it has also taken many of the Internet clients from cable due to low cost, which helps to drive the prices down. You do get what you pay for however. Hey DSL companies, here is an idea. Instead of trying to bring fiber to the home which you clearly can’t cost justify, how about just bringing it down the street so my little modem doesn’t have to connect 3 miles away across some 20 year old wires. If anybody needed a wireless option, the DSL companies do and they have boxes on almost every street. Having those assets for a wireless design would be my wildest dreams but for some reason, they can’t get off the wired mentality.

There are other revenue sources for this that I have covered in previous articles. Think through some ideas with cell phones, hot spots, multi-dwelling buildings, backhaul, VoIP, other ISP and business services, and the ROI actually starts dropping to about 2 years or less. If you have an existing company that already has sales people, project managers, and office staff in place, then the costs of getting to this point is pretty reasonable. Peg that at about $50K. Starting this project from scratch probably means about $150K. That adds 6-18 months on the ROI. Scaling the system and deploying more slowly puts out the ROI but reduces the Capex as the system starts paying for itself in about a year. There are many ways to play with the numbers but the bottom line is this, it’s now possible to compete with wireline services in any market. I’m also basing my numbers on what equipment can be bought today. I am pretty sure tomorrow may bring many more surprises that will change the financial and technology foundation of WiFi and that tomorrow is far closer than we think.

Chapter 9: I’m from the Government, I’m here to help you

Now let’s talk about the real-world in deploying this type of system. Realistically, light poles or traffic lights are the obvious deployment locations. They are usually spaced pretty optimally. The problem is they are either owned or operated by the local municipality or the local power company which in many cases, is overseen by a local governing board. Either way, the key word here is government.
I have dealt with municipalities that are both easy to work with and others that are very difficult to work with. It always comes down to the individuals within the departments. However, it also always takes a consensus of staff or departments to get a project through. The ability to get a project passed goes down as more people are required to make a decision and the more money the department has to expend. So getting approval to use municipal facilities generally takes a pretty long time, especially if involves the budgetary cycle.
Now you have to throw in the legalities of a deployment. You need some type of site lease for any facilities you are mounting equipment on. In addition, you might also need insurance in case something gets damaged. We have been required to carry a $2 million dollar policy for some locations. If you have to deal with property owners for buildings, the contracts get more complicated as there is the issue of sale of the building, acess, etc… Even though technically Triadland looks pretty easy, the devil is in the details.
When you go back to build financials for a deployment and you start adding in all the back end costs, you can see that unless you are expecting a lot of paying users, in the thousands, that a multi-million dollar Capex is going to kill the project unless you accurately predict the costs. If you are utilizing a lot of vertical assets, such as some of the models using 60 APs per square mile, and you have to pay for the rights to each of these poles with fees such as $10 per month per pole, then the monthly nut goes way up. Of course knowing you need 60 APs up front instead of thinking you need 30 APs and then later finding out you really needed 60 to begin with is far worse. The days of building a system and the users will come went away with the cell phone companies providing better bandwidth options. Although even Apple knows that WiFi can provide the bandwidth it needs for video applications, the cost and difficulty of managing a few towers versus thousands of APs makes it a no-brainer for cellular providers.
Although some of the cable companies have moved into the WiFi area with hot-spots to enhance their security, it’s not really a national standard for a business model. There is even discussion of cellular companies paying WiFi providers for access to their network. However, it’s evident that although WiFi has high-bandwidth capacity, defining the target client is key to profitability unless Verizon throws some petty cash your way.
As with any good business plan, in complete contrast to former companies that have failed in high-profile examples, the key is keeping Capex down, keeping monthly expenses down, providing a good quality service to retain and add clients, defining a realistic revenue stream, defining system expectations, and making sure you have control of as many facets of the product environment as possible. Sometimes this results in compromises in technical capabilities to balance out profitability and success. Building a system that costs $10,000 per square mile but generates $3000 per month in revenue with a $1000 per month of expenses is far better than building a $100,000 per square mile system that generates $6000 per month in revenue and costs $5,000 per month to support (keep in mind the cost of money needed to build out the system and manufacturer warranty costs) is not a better deal. There is nothing wrong with saying we can’t give 100% indoor coverage if 40% makes it profitable and 80% indoor coverage makes it unprofitable. If the system fails financially, it’s irrelevant what percentage gets covered.
I bring these examples up to show that it takes different designs for success in different applications. Although the industry idea of a municipal wireless system has traditionally been stick APs up every few hundred feet and build a system that is everything to everybody, the best design is the one that is self-sustaining financially which motivates the operator to keep it running.
Municipal Wireless by definition used to mean 100% coverage everywhere, similar to cell phones, with a universal product that was everything to everybody. We need to redefine it so that Municipal Wireless means any 802.11 service protocol deployed in a Wide Area model to provide bandwidth using a unique methodology that can’t be provided by existing cellular or satellite models. Start there and we have a whole new set of opportunities. Throw in 802.11N, MIMO, new 3.65GHz and 900MHz equipment, very low cost wireless equipment, and the possibilities are endless.
Instead of going to a municipality and asking them to be an anchor tenant, why not ask them to pay $10 per month to place a camera on your network or even better, you own the camera and lease viewing time to the city. It’s far easier for the police department and water department to find the funding to pay $100 a month for access to your camera than to Capex $1000 for a camera. Not only is the source of the funding different meaning different rules for purchasing, it also relieves them of hardware obsolescence, technical support costs, and internal training. Expand this idea out to other areas as well.
Many governmental departments are paying $40-$60 per month for cellular data cards. I can tell you for a fact that they are a mixed blessing. The lower bandwidth doesn’t work well for video uplinks. There are dead spots or areas where many of the systems slow down to lower rates and in many smaller cities, they are limited to 100K or less systems. Yes I know LTE and Wimax are here in many cities but try uploading a 3-6Mbps video stream and tell me how that works. Put up a system that can provide better outdoor coverage and they would gladly pay you instead of Verizon or Sprint. Assuming you have outdoor coverage taken care of to the vehicle, you don’t need laptop coverage everywhere because in reality, the city vehicle is a mobile hotspot itself. Use 2 AP’s in the car, $200 instead of $100, and you have a mobile hotspot with about 200’-400’ of coverage around the car. For improved performance in a mobile environment, a dedicated router product such as a Peplink Mobile Max or CarFi, or something similar might be better. I like the Peplink Mobile Max product because it has a load-balancing hardware VPN tunneling feature coming out for secured communications. In mission critical environments, I’ve even looked at using 2.4GHz and 900MHz in the same car simultaneously.
I know that it’s hard to get rid of the old ways. There are lots of manufacturers still building the same equipment they sold 5 years ago with minor changes to support 802.11N. Unfortunately, not even all of them have the ability or design to upgrade to 802.11N. The AP manufacturers need to figure out how to build a product that can make a deployment profitable if they want to get back into that market. If municipalities are the only clients, there is a limited market for too many manufacturers. What is needed is a model where private venture capitalists, many of whom have already been burned, see a business model that is not based on advertising, but based on reasonable costs and has solid income potential. It can’t be based on the idea that government officials are needed to make a business viable. We as consultants need to suggest that manufacturers get entry level prices way down, find additional sources of WISP revenue, and create an expectancy of profitability to drive the market. The manufacturer who does that will own the market.

Chapter 7 – One Size Does Not Fit All

Before we continue developing the system further, I think it’s a good idea to discuss all the various antenna designs that go into a municipal design process. I’ve described one type of design with omni-directional antennas, although I use many difference designs customized to the target client. It won’t meet all needs; no system will unless the budget is unlimited. It is being designed to be as flexible as possible, but there are specific technologies that may work better in some areas. Wireless hardware manufacturers have put forth various designs and optimized their hardware towards that goal. Budgets have sometimes dictated other designs such as “Tales from the Towers.” Due to new equipment that has been released, the numbers of potential designs that can be deployed have exploded.
Let’s start with the legacy systems that started the whole muni-wireless market. The most basic APs were single radios with a single, or dual, omnidirectional antenna design. These systems covered a fixed area and then simultaneously handled backhaul to the next radio. The first problem with this design was simply the fact bandwidth drops by ½ every hop. Although they also supported diversity for the antennas, that didn’t significantly increase the range. It did reduce fading since 802.11b wasn’t really created with a multipath environment in mind.
Eventually, manufacturers went to 802.11g and started adding 2-3 or more radios with secondary radios for backhaul. Using 5GHz frequencies to hand off the backhaul functions increased user throughput, and with dual 5GHz radios, the multi-hop bandwidth loss problem was effectively eliminated. The multi-radio design also spawned some extremely unique AP designs. Manufacturers started adding directional antennas, multiple frequency coverage, integrated sector antennas, beam-forming, and a few other ideas that don’t pass the smell test for actual performance advantages. However, the reason that there are so many systems out there is that there is an actual need for different features. I have used, and will continue to use, many of these products because of their uniqueness.
Jump forward to post-802.11N MIMO technologies, and the number of options from both technology and a budgetary position are mind-boggling. I typically go through no fewer than 5 designs and multiple products when trying to find the best design for a client. I still have questions on design ideas that I haven’t deployed yet that I’m testing. Since most APs today are multiple radios, the exception being the system we are designing for TriadLand, we are simply going to discuss the 2.4GHz side of the APs.
Because 802.11n is simply faster than b/g, we will stay focused there with the idea of backward compatibility. 1x1 MIMO, 2x2 MIMO, 2x3 MIMO, single-polarity, multi-polarity, and beam-forming are all being deployed. Which one is the best? Actually, most of them have some unique feature. It depends on the application. The right answer is the one that solves the problem within a specific budgetary or financial target. So does that mean there is a universal AP? The short answer is no. The really long answer, which I’m going to need 2 more pages to cover, is still no, but there are ways around most of the issues. Some of the answers, I really don’t know right now because I’m still testing some new ideas. Recent discussions and some new projects have gotten peaked my interest.
Let’s get back to our simplest AP design--our “Tales from the Towers” model. It’s a single omni-directional antenna on a 1x1 single stream 802.11 AP. If all clients are 802.11n compatible, then it can support 30-35 802.11b/g/n clients with a total throughput of about 30-50Mbps, TCP/IP. This assumes good LOS coverage, low-interference, and a low-reflectivity environment. We improved the range by using a very-high gain collinear antenna, which has a higher gain over most of the AP’s that use 6-9dBi antennas. It’s not perfect, but it’s cheap, and sometimes that’s all one needs.
802.11n has a distinct advantage over 802.11b/g, MIMO technology. To take true advantage of it, you need multiple either multiple antennas or multi-polarity dual-feed antennas. The question is, do you use multiple vertical antennas or multiple antennas in different polarities. Do you use 2x2 MIMO, 2x3 MIMO, or 3x3 MIMO? Which one works better with legacy 802.11b/g devices, and does it matter?
To answer that question, you first have to understand antenna polarity. The most commonly used polarities are vertical, horizontal, and circular. We used a vertical polarity omni-directional on our original design, which means vertically polarized in relation to the ground. We did it mainly for budget reasons, but how well it works depends on what the polarity of the client device is.
Let’s examine the typical laptop. Early WiFi-enabled laptops simply had small wires or circuit board antennas embedded on the WiFi card internally. Since the board/wire is typically laid flat in parallel to the table, the antenna would be considered a horizontal polarity antenna. So what happens when a vertical antenna connects to a client with a horizontal polarity antenna? The result is up to a 20dB loss of signal assuming both antennas on both sides are the exact same specification in alternate polarities. In reality, most laptops now have wire antennas that are run up the side of the LCD display and sometimes across the top. That gives it both a vertical and horizontal polarity. This is the exact same antenna design for your AM/FM car radio that is embedded inside the windshield.
Let’s start with the idea of how an antenna creates gain. Antenna gain effectively multiplies the signal being fed into it by borrowing the signal from other directions and refocusing it. For example, a 0dBi antenna is actually theoretical. It’s simply a point in space that radiates an equivalent amount of signal in every direction. Think of the center point of a ball. However, add a driven element and a reflector element, along a horizontal support arm at specific distances and you have a 2-element Yagi antenna that has 6dBi gain in one direction.
We will start with a 0dB antenna. A 0dB gain vertical antenna is really a 2.15dBi gain vertical antenna. That means it transmits 2.15db more power along the ground plane than it does straight up. If we make the antenna longer in multiples of the wavelength, then we get more gain. In reality, the highest non-collinear design I have seen is 12dBi in 2.4GHz. The resulting transmission pattern now gets squashed as less signal radiates upward and more signal gets transmitted along the ground for more range. Antenna theory is still developing with new algorithms coming out not only by engineers and scientists, but also by software programs that are discovering more efficient designs.
So how does 15dBi gain compare to 0dBi? In general, signal doubles in distance for every 6dB of gain. A 3dB signal gain increases the EIRP by a factor of 2. 6dBi gain would increase your EIRP output by 4 times which gives you about twice as much range. 15dBi antenna increases your range roughly by a factor of 6 times.
How does this play out in real life? Keep in mind that there will be obstructions in most areas. That means that getting ¾ of the way through a brick wall isn’t a whole lot more effective than getting ½ of the way through the wall. For walls or obstructions with less attenuation, we discussed how a 15dBi antenna can make penetration through an extra wall a reality due to a 6-8dB increase, or more, over the antennas that most metro APs used. A dual-polarity antenna with a lower gain can produce similar results. I have seen 2.4GHz multi-polarity antennas penetrate better than 900MHz single-polarity radios.
2x2 MIMO provides the option of 2 antennas, both in the same polarity or one horizontal and one vertical. There are even antennas that can do dual polarity or circular polarity in an omni-directional, or directional ,design. There are other variations on MIIMO, such as 2x3, 3x3, or more. If the antennas are directional, polarity is simple and cheap. If the antennas are omni-directional, vertical polarity is still cheap. Horizontally polarized antennas were much more expensive as gain goes up, but recent product releases demonstrate multi-feed dual-polarity antennas have come down significantly. Even dual-polarity parabolic dishes have dropped in price. We will cover these in future articles.
One of the more common horizontally-polarized antennas is the waveguide antenna. In an omni-directional design, they can deliver 13-15dBi, or more, of gain. Directional versions range from 14-18dBi. We used directional wave-guide antennas in some of our installations, and they worked great with 802.11b. One test we did demonstrated a laptop with a Cisco PCMCIA card connecting at 1.2 miles inside a fast-food restaurant.
Another popular design is the circular polarity antenna. The advantage to this antenna is that it transmits in all polarities simultaneously. The disadvantage over a single polarity antenna is that it sacrifices 3dB of gain for that multi-polarity coverage. Most circular polarity antennas are directional, although there are variations such as the Lindenblad design which is omni-directional. All antennas are compromises in terms of gain, direction, design, and cost. That is the reason it’s important to first define the target client before even considering any design idea.
There are a lot of variables to proper design of a system. Although the AP should be the easiest part, not including the antennas, beyond design scope, even firmware of the devices is important. Some APs handle packets differently than others. We discussed CPU overhead and real throughput in earlier articles. Firmware bugs and features also make a huge difference. Now throw in an antenna designs, network management, authentication, security, terrain, building construction, aesthetics, and even unknown challenges that occur after deployment, and this is when having a consultant who simply has more experience, provides value. However, even consultants are another variable, as evidenced by many differences of opinions and designs that have been deployed all over the world. Look for systems that are deployed and functioning and apply those ideas to your needs. Next month we get back to work since Grandma and Grandpa have now discovered Netflix.