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How Do Wireless Directional Antennas Work?

This week we’re going to take a look at wireless directional antennas and how they work. By understanding this, you can ensure that your Wi-Fi network provides the coverage you need for reliable, strong Wi-Fi links.

To create a wireless bridge or point-to-point link, you would use a directional antenna. Your coverage requirements will determine the size and shape of the directional antenna needed, as well as whether you are using them inside or outdoors.

First things first – What do we need in order to establish a long-range wi-Fi link? There are a few main requirements that we need in order to achieve this.

Remote Wi-Fi Links – 3 Requirements

We need to satisfy 3 requirements in order to set up a long-range Wi-Fi link. Whether your signal is indoors or outdoors, the basic needs remain the same. For example, the signal could likely navigate and pass through a thin wall indoors, or one tree outdoors. However, navigating an entire building of walls or a forest of trees would be more difficult.

When a wireless signal is traversing over longer distances, packets of data can be lost. Adding in other complexities (like many walls or trees) can cause problems with the signal.

So in order to establish and maintain a strong connection over a long distance we need to fulfil these 3 requirements:

  1. There must be a direct line of sight between the antenna and the receiver. This means no obstacles in the way, like buildings, walls or forests.
  2. The antenna must be elevated and be horizontal with the point that is receiving the signal ready to transmit it. For the connection to be strong, the antenna and the router for example, need to be on a level – Not one higher or lower than the other.
  3. The antenna must be directed towards the router or Wi-Fi transmitter. The directional antennas only emit and receive Wi-Fi signal in one single direction, so it needs to be positioned on that side. The accuracy needed for the position depends on the angle opening on the antenna. For example, the smaller the angle, the more accurate the position must be. More on that next!

Antenna Angles

How far a directional antenna can transmit a Wi-Fi signal depends partly on the size of its angle. For example, a directional antenna with a wide angle could transmit to a wider area around it, but not as long a range. A directional antenna with a small angle is a more focused transmission and will provide further coverage.

A good analogy to explain this is a light bulb. A bulb without a lampshade will emit light at an angle of 360 degrees. It works well to illuminate the area in close proximity, but doesn’t have great range in terms of distance. For example, lighting up one room.

In comparison, a bulb inside a torch operates at an angle of approximately 30 degrees. The light is much more directed, and thus has a further coverage range – But we don’t see light outside of the ‘sides’. The smaller the angle, the further the reach.

The same premise applies to wireless signal and directional antennas, as you can see from the diagram below.

Types of Wireless Directional Antenna and Their Uses

There are 4 main models of directional Wi-Fi antennas. They are designed to provide a Wi-Fi connection over long distances. They direct an entire frequency pattern in one direction to reach from point-to-point. A directional antenna receives the Wi-Fi signal and emits it forward; the distance it can cover depends on the angle it uses.

  1. Wireless Directional Antenna for Indoor Use – The 60° angle antenna

    A wireless directional antenna with an opening angle of 60 degrees is most practical for indoor use. The open angle of this directional antenna enables it to see all the Wi-Fi networks in it’s environment. It provides good quality signal over a range of up to approximately 300m.

  2. Wireless Directional Antenna for Long-Range outdoor Use – the 35° angle antenna

    This wireless directional antenna uses an opening angle of 35° which enables it to locate all the AP’s in a mesh Wi-Fi network outside the premises, covering a distance of up to around 800m. For this reason, it’s commonly used for long range networks. They are generally easy to install, are a manageable size and tend to come weatherproof so they can be used outdoors come rain or shine!

  3. Wireless Directional Antenna for Distant Networks – the 30° angle antenna

    These wireless directional antenna models have a closed angle. Their installation is a little more complex to the previous two models, and therefore is better suited to professional networks that need to cover very distant networks. Due to the closed angle, it is extremely important to get the positioning accurate.
  4. Wireless Directional Antenna for Professional Installers – the 7° angle antenna

    Due to these models of wireless directional antennas having a very narrow beam, it’s necessary to have them professionally installed. They are a favourite among professional Wi-Fi installers as they have a very high gain so provide a high wireless broadband casting range. High gain antenna can provide a strong Wi-Fi connection in all parts of your property from a single router. This type of directional antenna will have a parabolic reflector – basically a curved surface like a dish which direct the radio waves. This type of wireless directional antenna is ideal for long range networks.

If all this talk about wireless antennas has got you confused about which direction to go in, then why not give our Wi-Fi experts a call?

Working out of Hampshire, London and Cardiff, we can plan, design and install a Wi-Fi network that’s tailored to your home or business requirements. Get in touch with us today and we’ll have you better connected in no time.

 

 

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4G 4G LTE 5G Wireless Network
What’s the difference between LTE and 5G?

There has been much hype surrounding 5G, relentlessly for years. Now as part of a global rollout we see 5G available in most major cities as well as some towns and more rural areas. Soon enough, we’ll be using 5G just as we use 4G as the standard.

But 5G is still new to the wireless scene. And for some, the question is – Do we really need 5G when we’ve got LTE?

Many of us are still depending on long-term evolution technology. Indeed, there are only a few areas in the UK that don’t have any LTE presence.

What is LTE?

LTE was first launched back in 2009, and whilst it took a number of years to become part of our national connectivity fabric, it is still now a standard for wireless communications.

The reason for its staying power is down to its reliability and stability – Leading many wireless users to wonder if they even need to move over to 5G.

What is the difference between 4G LTE and 5G?

It was necessary to identify LTE as an element of the 4G standard as many telecoms companies weren’t actually able to provide 4G speeds due to infrastructure. The regulator ITU-R (International Telegraph Union Radiocommunication) established LTE as a standard to show the progress being made towards true 4G.

The download/upload speeds of a particular standard can be different in theory and in practise. Whilst in theory, 4G LTE can achieve data transfer speeds of up to 150Mbps for downloading content and 50Mbps for upload speeds, in practise is is more likely to be 20Mbps and 10Mbps respectively.

These figures will vary depending on:

  • Location
  • Network deployment
  • Traffic

How does 5G compare to 4G LTE in terms of download speeds?

5G connectivity offers theoretical download speeds of up to 10Gbps. A pretty staggering difference! Of course in practise, it may not reach this, but even real-world examples seem to still be dwarfing the speeds of 4G LTE.

Why does 5G reach higher speeds?

5G uses a different spectrum to 4G – Called mmWave which are high-frequency bands. The higher speeds are mostly reached because these high frequency bands support more bandwidth than the ones that LTE uses. This means that more data can be transferred at once.

5G can also use frequencies above low-band but lower than 6GHz. Despite these not supporting the highest possible speeds, they will still outclass 4G LTE. It’s worth noting that 5G coverage could be further expanded by using connectivity below 6GHz, especially as walls and surfaces can block mmWave frequencies.

Basically, 5G uses a different spectrum to 4G LTE and thus:

  • Delivers stronger, faster connections
  • Has a higher capacity for traffic
  • Has low latency (1ms)

Sounds too good to be true doesn’t it! It’s worth remembering that the rollout of 5G is still in its infancy, and therefore coverage is still limited. Before the big networks like EE, Three and Vodafone can deliver the top scope of what 5G has to offer, more work needs to be done.

So should we be choosing LTE or 5G?

As with most techy things, there are lots of factors, such as:

  • Your budget
  • Where you’re based
  • What your connectivity needs are – Personal or business

The more countries adopt and expand their 5G infrastructure, the more 5G-friendly hardware we will start to see. The best way to know whether to choose LTE or 5G is seeing what is on the market and whether it meets your needs.

You may find that some of the 5G devices available don’t have a 4G alternative. You may also find that they are rather on the pricey side! So definitely shop around.

Of course, the more 5G devices we see on the market, the more we will see the prices start to come down. So the time for adopting 5G over LTE may not be quite yet. Patience could also serve you more of the promises 5G has to offer – The more the 5G coverage continues to expand, the higher the speeds and the more consistent the connection to mmWave networks.

Since 2019, we’ve seen prices start to come down as competition in the market starts to heat up, but 5G is still costly. If you have a big budget then you could just go for it now, but we feel like the overall coverage, packages and prices will continue to rapidly improve. We’re inclined to hold out a bit longer and stick to LTE for the time being.

What about 5G for business?

If your business relies on heavily on connected sensors and other similar IoT networks then 5G may be the network you’ve been waiting for. The bandwidth and low latency that 5G could bring to your business cannot be easily ignored.

Think driverless cars navigation and smart sensors – 5G could well be the communications technology that will enable some great and creative deployments.

What are the health concerns associated with 5G?

With 5G comes questions about whether it could harm our health. Do you remember when mobile phones were beginning to emerge into mainstream use and there was much anxiety about what the radio waves were doing to our health? Mobile telephone has never been without concerns, but 5G seems to have evoked more than its fair share of health worries.

The installation of 5G masts have been banned in multiple UK locations. And it’s not just parts of the UK that are opposed to 5G – Back in 2017 180 scientists from 36 different countries made a public appea to the EU to pause their plans of 5G expansion whilst investigations were carried out looking at the long-term effects on human health.

Whilst both 4G and 5G use radio waves, 5G uses higher frequency waves. It’s these high frequency waves that provide better network capacity and speed.

Studies that have looked into any potential health risks from 5G haven’t seemed to identify any specific danger from 5G.

What is the future for LTE and 5G?

With the rise of 5G comes potentially society-changing connectivity – Like self-driving cars.

But technological advances can be slow if not steady. Whilst there is definitely potential for 5G to take over, it could take considerable time for 5G-enabled devices to really take hold of the market. Even from the likes of Apple!

There is still space for 4G LTE in our networks, and whilst it may be 5G’s predecessor, it’s not going anywhere just yet.

Research from Ericsson suggests that the dominant cellular network technology seen in most regions globally is still 4G LTE. 78% of mobile subscriptions in Western Europe in fact! Just because the 5G rollout is well underway, doesn’t mean that everyone will immediately jump ship and drop 4G LTE. It’s expected that 4G LTE will still be the dominant network even 5 years from now.

By 2026 Western Europe is predicted to be using 5G in 69% of all mobile subscriptions. However, Ericssons findings suggest that even as 5G usage surges, 4G LTE won’t automatically decline. It’s even predicted that 4G LTE availability will grow, with global coverage of 95% by 2026, with 5G only seeing 60% in those 5 years.

There is no denying that 5G is the future for telecoms. But by the time we are all accustomed to using it, 6G might well be on the way! Despite 5G becoming more prevalent as time passes, we still think there’s no need to be abandoning 4G just yet.

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Business Wi-Fi DFS Channels Home Network Home WI-Fi Wi-Fi
Can I Use DFS Channels on my Wi-Fi Network?

We’ve recently started to see a rise in customers using DFS channels when operating their Wi-Fi networks, so thought we would write an article all about it in case it’s also helpful for your own network.

What is DFS?

DFS is Dynamic Frequency Selection and is a type of Wi-Fi function that allows WLANs to use 5GHz frequencies (which are reserved for radar, for example, the military, satellite or weather).

What is the benefit of using DFS channels for Wi-Fi?

We’ve written before about how you can improve your Wi-Fi and prevent interference by utilising different channels. The main benefit of using DFS channels taps into this. You can increase the number of available Wi-Fi channels by using DFS channels to use these less-used frequencies.

How can I utilise DFS channels on my Wi-Fi network?

The first thing you need to do if you are wanting to use DFS channels, is to check that your wireless access points and wireless clients support the necessary functionality.

The 5GHz spectrum in the UK is broken into 3 different bands and runs from 5150MHz (5.15GHz) to 5850MHz (5.85GHz). The bands are as follows:

Band A

  • Channels 36 – 64
  • This is used only for Indoor wireless
  • Does not require a license

Band B

  • Channels 100 – 140
  • Can be used both inside and outside
  • Does not require a license
  • Hardware must conform to DFS standards and be DFS enabled

Band C

  • Channels 149 – 161
  • Can only be used outside
  • Requires a license from Ofcom
  • Hardware must conform to DFS standards and be DFS enabled

 

 

Checking DFS Channel Availability

When you enable DFS, the Wi-Fi access points will need to verify that any radar in the proximity is not using DFS frequencies. This is a process called Channel Availability Check and is carried out during the boot process of an AP as well as during normal operations.

Should an AP detect that a local radar is using a certain DFS channel, it will automatically exclude that channel for this list of available ones. This will last for 30 minutes after which time the AP will check again to see if the channel can be used for Wi-Fi transmissions. You’ll be pleased to know that this exclusion of unavailable channels has very little impact on Wi-Fi clients.

DFS channels are not immediately available when an AP boots. This is because the Channel Availability Check can take anywhere between 1 minute and 10 minutes during the boot process.

 

What happens if an AP detects radar use during normal operations?

We know what you’re thinking – What happens if the AP was to detect during normal operations that the channel you are using becomes in use by a proximal radar?

If this happens, then the AP may communicate to its Wi-Fi clients to stop transmitting on that particular channel. The AP will then switch to a different, available DFS channel within the Channel Move Time. This is usually about 10 seconds.

Unlike above, this could affect Wi-Fi clients. An AP won’t always announce that it is changing channels to connected devices. When it switches to the available channel, it will cause those Wi-Fi clients to disconnect from the network and then re-connect to the new channel.

 

Are DFS channels right for my Wi-Fi network?

If you are considering using DFS channels for your Wi-Fi, you need to think carefully about whether business critical operations rely on that connection. If the answer is yes, you might want to avoid enabling DFS and not risk the disconnections caused by DFS frequencies.

 

by admin
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Business Wi-Fi Wi-Fi Wi-Fi Advice Wi-Fi Design Wi-Fi Installation Wi-Fi Interference Wi-Fi Site Survey
The Fundamentals of a Wireless LAN

We were going to call this blog ‘WLANs for Dummies’ but that seemed a bit harsh so we settled on the fundamentals of a wireless LAN instead.

A wireless LAN, or WLAN, might seem complicated on the surface but actually it really just follows simple laws of physics. If you can understand these and follow them, then there shouldn’t be any reason why you can’t achieve high performance and scalability for your WLAN.

If you can understand the basics of wireless physics, then you can start to plan your WLAN for a successful deployment. It will also help you to troubleshoot an existing WLAN exhibiting issues.

How Does Data Travel Through a WLAN?

First things first – Let’s look at wave properties.

Data transmits, or travels, from one point to another – e.g. between wireless access points – via electromagnetic waves. This energy travels at the speed of light and operate at different frequencies.

The frequencies of these electromagnetic waves are defined by how many periodic cycles are completed by second.

For example:

How is Frequency Measured?

As we said above, frequency is how many wave cycles are completed per second. This is measured in Hertz. A 2Hz waveform is 2 completed wave cycles in a period of 1 second.

How Does Frequency Affect a WLAN?

A phenomenon called Free Space Path Loss is something that causes signal loss when a waveform travels from one point to another. This is what affects how well data travels across a wireless network.

Different wavelengths (frequencies) experience difference signal loss. The lower the frequency, the longer the wavelength, and the longer the wavelength, the further it can travel before signal gets lost.

For example, 2.4GHz have longer wavelengths than higher frequencies like 5GHz.

How is Wi-Fi Signal Loss Measured?

We measure the energy that is associated with received wireless signals in Decibels (dB). We can also measure loss of signal in this way.

Decibels are logarithmic. On the linear domain, when you add decibels it grows exponentially and when you subtract decibels it reduces exponentially.

The 3dB rule

Every 3dB change, there is a doubling of energy (if increasing) or a halving of energy (if decreasing).

As a ratio, this would look like:

If we had the wireless signal energy at
1:10dB

Then doubling it would be
2:13dB

Remembering this rule can help with both analysing the energy associated with wireless signals as well as predicting it.
Similarly, if you add or subract 10dB, it changes by a factor of 10.

The Relationship Between Frequency and Wireless Signal

Let’s take a look at 2.4Ghz and 5GHz frequencies or waveforms. 5GHz is a higher frequency, so has more wavelengths in a given time period. 5GHz has more wireless signal loss (attenuation) than 2.4GHz, and thus is better for high-density areas. 2.4GHz has less wavelengths in a given time period and is better suited for wider coverage. Bear this in mind when you are planning or troubleshooting a wireless network.

How is Wireless Signal Affected by Different Materials?

In an ideal world, you would have a clear line of sight between your wireless points. In reality, this is rarely the case and you will often find things that get in the way and stop the wireless signal from traversing effectively across your network.

Different materials will affect wireless signals and attenuation in different ways.

Materials such as concrete will cause more attenuation of wireless signal than wood.

In scenarios where wireless signals can propagate (the action of spreading) normally, there is no interference from other materials. However, there are some things that can alter the propagation of a wireless signal, causing it to behave differently and potentially become unreliable.

For example, a WLAN environment with metal surfaces may encounter unpredictability with wireless signal due to it reflecting off the metal.
Wireless signal can also be absorbed by certain materials like water or people, causing the signal to falter.

Being mindful of materials during the WLAN planning stage can help ensure the environment doesn’t hinder your wireless network and you have reliable connectivity results.

Co-Channel Interference

Different materials aren’t the only thing that can interfer with wireless signals.

Due to the 2.4GHz and 5GHz frewuency bands being unlicensed, there are no restrictions on people when extending wireless networks with access points.

This means that they can become crowded as well as channels not being assigned efficiently. Both of these issues can cause co-channel interference.

When planning your WLAN it’s important to take these issues nito consideration and plan your wireless network accordingly so as not to risk problems with wireless signal later down the line.

You want your WLAN to be as effective and efficient as it can possible be, which takes planning and wireless network knowledge.

Whilst the 2.4GHz is popular due to its propagation qualities due its waveforms passing through materials like walls more easily and reaching end users at a long distance. This however has meant that its become crowded with competing devices such as cordless telephones, baby monitors and bluetooth devices. This saturation can cause problems with your wireless signal.

In comparison, the 5GHz spectrum has greater availability and relaxed transmission power giving it more flexibility when it comes to wireless networks.

The 2.4GHz band has only 3 channels without any overlap, whereas the 5GHz has 24. This is another reason why the 5GHz band is favoured for high-density WLAN environments.

Understanding Frequency Channels

To ensure you can maximise the performance and scalability of your WLAN, you need to understand how these channels operate and use that knowledge to avoid co-channel interference.

Let’s take an Access Point as an example. An AP will have a specific bandwidth through which it will transmit and receive signals to and from other points. The channel assigned to the AP will be appropriate for the centre frequency of the first 20MHz channel used by the AP.

This bandwidth is specifically the frequency range over which the data signals are transmitted. Peak transmission and power is spread over the range of that bandwidth, with it dropping off at the edges.

These edges are then at risk of meeting other nearby wireless networks and are prone to interference from the ‘noise’ of these other networks.

It’s important to use what you know about channels to prevent the reduction of wireless signal speed and loss of scalability of your wireless network.

In order to minimise interference between neighbouring access points, choose to assign them with non-adjacent channels. Following this will make it easier to scale your network. If you don’t follow this principle, you will likely encounter problems with latency and throughput.

The best way of reducing interference when assigning WLAN channels is to carry out a Wi-Fi site survey. This involves analysing the noise levels across the spectrum so you can make informed decisions for your wireless network.

Call The Experts

If this all sounds a bit complicated, then why not give us a call here at Geekabit? We have Wi-Fi expert engineers working out of Hampshire, Cardiff and London who can take care of all your Wi-Fi woes.

From Wi-Fi site surveys, to planning and installation, we’ve got your WLAN covered. GIve us a call or drop us an email to see how we can help keep you and your business connected.

by admin
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Outdoor Wireless Network
Which Ubiquiti airMAX product should I choose?

It’s no secret that we’re big fans of Ubiquiti products here at Geekabit. We often recommend their devices and bits of kit for our clients and business Wi-Fi installations.

This blog is going to look at some of the different Ubiquiti airMAX products there are and which ones might be suited to your business and Wi-Fi needs. There are lots of different options that cover various outdoor wireless scenarios.

 

Point-to-Point or Point-to-Multipoint?

Let’s start at the beginning. First you need to ascertain whether your outdoor Wi-Fi would be best suited to a Point-to-Point (PtP) or Point-to-Multipoint (PtMP) network. These are the two primary deployment methods for distributing any fixed outdoor wireless communications.

Point-to-Point (PtP) – This method connects two locations, usually at a distance of multiple km, and essentially forms an Ethernet bridge.

Point-to-Multipoint links (PtMP): This method can connect three or more locations, via one Base Station (or Access Point) and multiple CPE devices (Stations) connected to the Access Point.

 

Point-to-Point (PtP) Links

Here are some of the Ubiquiti airMAX products with specifications on what wireless environment they would cater for. Whilst there are distances listed below, these are meant as a reference. It’s important to bear in mind that all real-life results have influencing environmental factors, for example, interference and Line of Sight.

Short distance (0-5 km)

NanoBeam 5AC-G2: This is recommended for short links, and exhibits superior performance which is due to the latest airMAX AC technology. It is able to deliver up to 450Mbps of throughput.

NanoStation 5AC Loco: Another good option for short distance links, this is the lowest cost PtP solution that has airMAX AC technology.

NanoStation 5AC: This one is a popular choice when it comes to short link Wi-Fi, and is commonly chosen for video surveillance due to its dual-Ethernet port capability. It also has airMAX AC technology.

Medium distance (5-15 km)

LiteBeam 5AC-23-G2: This is recommended as Customer Premises Equipment (CPE – any device accessing the internet) for most cases. Thanks to the latest airMAX AC technology, it has superior performance and can to deliver up to 450Mbps of throughput.

PowerBeam 5AC-G2: Recommended as CPE for medium or long distance links. Once again it has superior performance thanks to the latest airMAX AC technology. It can to deliver up to 450Mbps of throughput.

PowerBeam 5AC ISO:  This one is very similar to PowerBeam 5AC but offers an alternative for high-noise environments.

 

Point-to-Multipoint (PtMP) Links

When it comes to PtMP outdoor wireless networks, it’s really important to remember that the performance is dependent on both sides of the link. If you are trying to get across long distances, you’ll need to make good choices when it comes to the Base Station and CPE for each case. We’ll be looking at these options below.

The release of Ubiquiti operating systems airOS 6 (for M devices) and airOS 8 (for AC devices) provides backwards compatibility and means that you can upgrade your M sector by simply swapping the M AP for an airMAX AC radio as the AP.

 

Base Stations

You will usually find the location of a base station on the top of a tower, building or mast. Your maximum coverage will be determined by the height of that tower.

Low Capacity and Short distance Base Stations

For short distance base stations with low capacity, take a look at the following Ubiquiti airMAX products. These are ideal for areas with low interference.

Rocket M + airMAX OMNI antenna: This could be a great option for more rural Wi-Fi needs, particularly as it is susceptible to interference. It can support up to 60+ concurrent stations when all devices are airMAX capable.

High Capacity & High-Performance Base Stations

Rocket 5AC PRISM G1/G2 + airMAX AC Sector Antenna: This one’s for the highest performance base stations with carrier-grade system. Eight 45° antennas give 360° coverage. Co-adjacent noise is significantly reduces with airPRISM technology.

Rocket 5AC Lite + Titanium Sector Antennas: For medium-high density areas, this is a high-performance solution. It uses the latest airMAX AC technology plus variable beamwidth (60-120°) antennas for scalable growth.

LiteAP AC: This one is an ultra-lightweight airMAX AC sector + radio. It has incredible performance and disruptive pricing, plus 120° coverage.

 

Customer Premise Equipment (CPE)

One of the great things about Ubiquiti is the range of products and how they can work together to support your wireless network as a whole. If you go for the airMAX CPE to support your Ubiquiti products, you’re also getting centralised SDN management, hotspot/guest portal, advanced SSID/WLAN configuration, routing, switching and more. It’s well worth looking at the whole range available. Or call the experts (that’s us) to see whether Ubiquiti wireless devices could help with your wireless network.

Short distance (0-3 km)  

NanoBeam 5AC-G2: This has slightly greater range than the NanoBeam 5AC-19 M and is more directive.

Medium distance (3-7 km)

LiteBeam 5AC-23-G2: This low-cost CPE has very narrow beamwidth, and MIMO technology. This one is the new industry-standard for airMAX AC CPEs.

PowerBeam 5AC-G2: This option is a highly directive CPE, with better range and lower noise.

Long distance (7+ km)

PowerBeam 5AC-500/620: This one is a higher power device, with a super directive antenna, better range and lower noise. If you’re a design buff then you might also like how it’s more aesthetically pleasing compared to bulky dishes.

Rocket 5AC-Lite + RocketDish LW: You’ll likely find this one the best performing option. It’s higher cost than integrated designs, and can be unsightly as a CPE. It supports IsoBeam accessory for better isolation, which comes with RF chokes.

 

Frequency Options

Let’s talk about frequency. Due to physics and utilisation, each frequency has different characteristics.

Lower frequencies have better propagation characteristics than higher frequencies. You may find that they work better in environments where the Line of Sight is obstructed (for example, by trees). However, these bands may also have higher levels of noise and interference, so it’s very important to select the frequency that works best for your wireless environment.

Let’s have a look at the pros and cons of some frequency bands.

900MHz (M900) – Pros and Cons

  • Better tolerance for trees and small obstacles in comparison to higher frequencies
  • Tends to have higher noise levels
  • Only has a 26MHz bandwidth

2.4GHz (M2) – Pros and Cons

  • It is unlicensed worldwide
  • It only has 3 over-lapping 20MHz channels (1, 6, 11)
  • It tends to be a very crowded band with interference from other devices such as cordless phones
  • 40MHz channelse are not recommended

3.x GHz (M3-M365) – Pros and Cons

  • 300MHz bandwidth in countries where 3.4-3.7GHz band is available
  • It is noise free in most areas
  • Only 25MHz bandwidth in countries where 3.65GHz can be used
  • It requires a license

5 GHz (5AC/AF5/AF5X) – Pros and Cons

  • It is unlicensed worldwide
  • Higher EIRP limits allow higher gain antennas, and long distance links
  • Large amounts of spectrum available, easier to co-locate nearby devices
  • Weaker propagation in comparison to lower frequencies when there are obstacles like trees or walls are present

10 GHz (M10) – Pros and Cons

  • It is noise-free in most cases and is very useful when the 5.8GHz band is crowded
  • It has a very small Fresnel zone
  • It is only available in a few areas
  • It is a licensed band
  • It needs a perfectly clear Line of Sight

11 GHz (AF11FX) – Pros and Cons

  • It is noise-free in most cases and is very useful when the 5.8GHz band is crowded
  • It has a very small Fresnel zone
  • It is only available in a few areas
  • It is a licensed band
  • It needs a perfectly clear Line of Sight

 

Antenna Types

We spoke about the important of each side of the link being effective to ensure the highest performance possible. Now it’s time to talk about the antennas.

High gain antennas also play an important role when deploying a high performance outdoor wireless network. There are two main reasons:

  • They provide high gain amplification of the signal power resulting in higher signals and better link quality.
  • They are highly directional, which gives them spatial filtering characteristics that can help to block noise. This is especially important in noisy environments.

When thinking about the antenna for the base station, you might think it’s best to go for the one that offers the largest coverage area. However, it’s actually better to choose the antenna that covers the smallest amount of coverage that covers your range area. An antenna covering a larger area than needed could be more susceptible to interference due to a wider beamwidth, causing a decrease in scalability and performance.

Here are the categories of antenna.

Yagi: Directive, used for PTP and CPE applications. Frequently used in low frequencies, such as 900MHz, due to size

Grid: Directive, used for PTP and CPE applications. Great wind-loading properties. However, this type only works in one polarity (1×1), so lower performance than 2×2 antennas (Dish, Panel, etc.)

Panel: Directive, used for PTP and CPE applications. Compact design is very attractive in situations where dishes are not preferred.

Dish: Most Directive, highest performing airMAX antennas for PTP applications. Usually larger and heavier.

Omni: Provides 360 degrees of horizontal coverage (omni-directional). Ideal for low capacity and wide-coverage AP / Base Station applications)

Sector: Ideal choice for high performance Base Stations. Offer higher gain and directivity than omnidirectional antennas. Usually offered in 45, 60, 90, or 120 degree options.

This list is not conclusive. You can find all of the current airMAX antennas here by looking at the antenna section.

For more information in general about Ubiquiti airMAX options, head to their website.

 

No idea where to start?

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Technology Wi-Fi Advice
WiFi Faces Technical Challenges

The emerging wireless standard promises better WiFi but the promise introduces significant complexity.

IEEE 802.11 standards (g, a, n, ac) delivered WiFi performance improvements out of the box. They focused on progressively increasing the data rate over the wireless link. All that was needed to take advantage of any new standard, was a radio chipset that incorporated the new radio and MAC enhancements.

The situation is different for the upcoming 802.11ax standard. The focus of 802.11ax is not on increasing the data rate but on improving the overall wireless network performance. This introduces significant new radio and MAC enhancements such as OFDMA and BSS colouring.

Ranking high among the issues is a transmission-scheduling mechanism. The downlink transmission scheduling in WiFi has been a simple FIFO (First In First Out) system. 802.11e introduced a small variation regarding the maintenance of multiple transmission queues for different priority classes.

However, 802.11ax introduces significant complexity in wireless transmission scheduling due to its OFDMA and MU-MIMO enhancements.

  •  With MU-MIMO, there is now an option to transmit a single wireless frame to a single client or concurrently transmit different wireless frames to multiple clients using multi-user beamforming.
  • With OFDMA, there is now an option to transmit a single wireless frame to single client using traditional OFDM or concurrently transmit different wireless frames to multiple clients using subsets of channel width.
  • 802.11ax introduces multi-user transmission in uplink direction too. The AP needs to schedule multiple clients for concurrent uplink transmissions according to their requirements.

These methods need to take into account service requirements of traffic flows, radio conditions on the channel, client capabilities and client state feedbacks. It is no easy feat to come up with scheduling mechanisms that will work in most practical scenarios with relative ease of configuration and fine tuning.

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Uncategorised
Wi-Fi Frequencies: An Overview

With all of the current and future Wi-Fi frequencies and technologies are really getting confusing, with that in mind theres actually more than you realise. So let’s take a look at what’s out there and what’s coming up, as well as trying to make it as simple as we can.

There are two common well known dominant Wi-Fi frequencies used by 802.11a/b/g/n systems, 2.4 GHz and 5 GHz. Almost all modern Wi-Fi devices are made to operate in one or both of these frequencies. These frequencies now dominate most of our homes.

The same basic OFDM technology used by 802.11a in 5 GHz is also used in a 4.9 GHz public safety band. This band is 50 MHz wide it requires a license and is only available in some regulatory domains. There are specific and limited purposes for this band so you won’t see a lot of commercial interest or attention here.

The FCC also opened up 50 MHz of bandwidth in a 3.6 GHz licensed band. OFDM is used here as well. In the US this band requires a license but usage is not limited to certain technologies, so the band will be shared.  There aren’t many benefits to this frequency band and the interference avoidance requirements represent a moderate R&D requirement without much ROI.

You’ve most likely heard about this PHY spec in development. It builds on 802.11n MIMO technology in 5 GHz and seeks to expand on the HT PHY with a few developments that are a natural next step. 802.11n gave us 40 MHz bonded channels. 802.11ac will give us 80 MHz channels and, likely, 160 MHz channels.. 80 MHz bandwidth will get us past the gigabit rate threshold. MIMO will also be expanded to 8×8, but since client devices aren’t adopting that type of power hungry radio anytime in the near future (or ever), 8×8 will be used for MU-MIMO. MU-MIMO allows an AP to transmit simultaneous downlink frames to multiple users (MUs).

VHT 60 GHz (802.11ad) — This PHY opens up a fresh use case for Wi-Fi in the form of very high throughput at short range. There are a lot of challenges getting the kind of range that would be useful to enterprises. We’ll see short-range, high bandwidth applications, but there are still failings to see the exciting benefits that have been touted in the press.

White-Fi (802.11af) — The TV whitespace frequencies between 50 and 600 MHz have also created some exciting buzz in the past several months. There are many articles out there discussing the limitations and benefits of this band. The main issue with this frequency is that contiguous bandwidth is in short supply, so we see a handful of 6 MHz-wide channels, which will yield lower transmission rates than 802.11a/g. The merits of a low frequency are fairly well known; that is, despite the throughput-deficient bandwidth, the range and coverage is advantageous. Rural broadband applications are the evident winner with this technology where coverage is more important than bandwidth and high user density.

It is also worth mentioning 900 MHz. Back in the 1990s, 900 MHz was a popular pre-802.11-Wi-Fi frequency. It is an unlicensed ISM band. This is a semi-popular broadband frequency with decent range and limited throughput. Many vendors use proprietary PtP and PtMP solutions here for wireless distribution, but they are not defined by 802.11 and they are not designed for client access.

Wi-FI frequencies in brief:

  • 50-600 MHz TV Whitespace — Good range, low capacity.
  • 900 MHz — Proprietary PtP and PtMP. Decent range, slow rates.
  • 2.4 GHz — Well-known and used.
  • 3.6 GHz — Little-used, licensed band.
  • 4.9 GHz — Licensed public safety band.
  • 5 GHz — Well-known and used, the future of Wi-Fi.
  • 60 GHz — Short range, very high throughput.
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