1. What is Fixed Wireless Access?
Wireless Data Communication uses Radio Waves to transmit Data, mainly Internet Data, ‘over the air’ to end-points requiring Internet Data Access. This has an advantage over cabling systems including Fibre Optic cables.
Wireless has a huge advantage insofar it being extremely quick and easy to deploy; it only requires Base Stations from MNO’s at reasonable distances away from the Customer’s premises.
Furthermore, the most modern techniques used to communicate Data via a Radio signal have improved to the level where it can achieve very satisfactory Data transmission rates i.e. good Upload/Download performance.
The transmission of Data from a MNO to premises as mentioned below is known as Fixed Wireless Access (FWA) as it refers to the use of Wireless Data Transmission between two Fixed locations.
These ‘fixed locations’ are the MNO’s ‘Base Stations’ on the one side, connected to the Internet, communicating with Customer Premises Equipment (CPE’s) like Routers located in Residences, Offices, Factories, Industrial Sites like Manufacturing Plants, Mines etc.
2. What is an antenna?
An Antenna provides the means of ‘capturing’ the Radio Signal sent by the MNO’s Base Station. Many Routers use by MNO’s have ‘built-in Antennas however if you look at Figure 1. Below you will see that Radio Signals have difficulty in penetrating the walls and outside structures of most environments where they are deployed.
This is where an external Antenna can make a huge difference between an extremely unhappy customer and the contrary. There are however a few basic principles an external Antenna needs to provide to be successful in providing a good Signal level to the Router.
2.1. What is a good Antenna?
In order to receive all the Signals at the different frequencies, a good Antenna should be capable of receiving all the frequencies a MNO is likely to transmit/receive at. It is important to ask the manufacturer for such a ‘frequency response’ chart. At Poynting we pride ourselves as one of the top designers of Antennas in the world and this shows in the frequency response of our Antennas.
The Gain of an Antenna is a measure of improvement provided by the Antenna. The higher the Gain of an Antenna, the better its capability to receive weaker signals. At Poynting we pride ourselves not only in good frequency response as mentioned above, but also the best Gain per frequency in the industry.
The third important characteristic of an Antenna is its Radiation Pattern. This is a measure of how good the antenna responds to all the frequencies from the direction of the Base Station Tower, in other words, how good the Gain is in any given direction.
Antennas are divided into two main categories, Omni-Directional- and Uni-Directional, also just simply known as ‘Directional’ Antennas.
1.1.1. Omni-Directional Antennas:
1.1.2.Uni-Directional Antennas (or just, ‘Directional’ Antennas)
As the name suggests these are external Antennas capable of receiving Radio Signals from any direction. The Radiation Pattern of these Antennas resembles a circle when considering the Horizontal plane. This means that the Antenna can be oriented in any direction, and it will still have a good standard frequency response at a good Gain factor.
Again, this is where Poynting provides you with an excellent solution. Our Antennas has near perfect Omni Directional Radiation patterns meaning that you will get the best performance in terms of gain at any MNO standard frequency from any direction.
Again, as the name suggests, these are Antennas made specifically to receive Signals from a particular Direction. The application areas for these Antennas are situations where a Single Base Station Tower is the only Source of MNO transmission in the Area.
Our Poynting Antennas, like our Omni-Directional Antennas, has exceptional directional performance. This means that the Gain of our Directional Antenna is excellent in the Direction of the MNO’s Base Station at all the standard frequencies the MNO wish to transmit/receive at.
3. Why an External Antenna?
Modern communication systems all use a mechanism known as Cyclic Redundancy Checking (CRC) to ensure that the integrity of communication uploaded or downloaded via the Radio Internet connection is not compromised. If the CRC of the uplink/downlink fails the communication system requests a retransmission of the Data lost in transit between Base Station and the CPE, the router.
The biggest single factor causing constant Data retransmission is poor signal quality.
If a large proportion of users connected to a particular Base Station experience poor Signal quality, the Signal processing mechanisms of the Base Station starts limiting the bandwidth available to individual clients and the end- result is extremely poor Data transmission performance i.e. extremely poor Upload/Download also known as high Bit-Error-Rate (BER).
Routers designed to receive Signals from MNO’s typically have Internal Antennas. These Antennas perform well under certain circumstances only. It has been shown however that the penetration of MNO Signals to inside building is a huge challenge and the Signal inside a building can be as much as 100 times weaker than outside the building.
It is therefore clear that an External Antenna with an excellent Gain factor, excellent frequency response and excellent Omni- and/or uni-Directional capability will provide a much better Signal resulting in much better FWA performance.
This weakened signal causes a poor SINR, Signal-to-interference-and-Noise-Ratio which, due to the high BER in turn forces the Router to ‘fall back’ to lower order demodulation like Quadrature Phase Shift Keying, QPSK, a mechanism employed by Base Station transceivers to preserve data integrity in poor SINR environments.
Figure 1. above shows the two scenarios, Indoor Antenna vs. Outdoor Antenna. In this example the Indoor Antenna has a Gain factor of 1.2 vs the Outdoor Antenna ha a Gain factor of 2,
If all subscribers in this example had an Outdoor Antenna with improved Gain factor, the Base Station will be able to comfortably reach 150 customers. In contrast, none of the customers had Outdoor Antennas, the Base Station can only provide satisfactory service to 40 customers, clearly a huge improvement for the MNO.
This means that 60/150 = 60% of the customers in this example will enjoy the full benefit of the highest possible throughput and therefore performance form their FWA service provided by the MNO.
Conclusion: Cost benefit Analysis of an External Antenna
Having said all of this, this is an opportunity for MNO’s to add an external Antenna, to the Routers they provide, as part of their service. This will go a long way in providing their customers with a good FWA with the best possible data download/upload performance increasing customer satisfaction.
A cost vs. benefit analysis easily clears this argument in favours of installing an External Antenna. Consider the cost of an External Antenna as depicted in Figure 2.
Figure 3. above summarises the Cost Benefit of the External Antenna scenario. It is clear that without the increased SINR, as per Figure 1. And 3. Above, the MNO can only reliably reach 40 Customers resulting in a monthly income of €19 200.00 in a 24 month period.
Contrast this with being able to reach 150 customers in the same sector. Even though the cost of the Antenna + Installation comes to €39 000.00, the Revenue has now increased to €72 000.00 over the 24 month period resulting in an increased Net Income of €33 000.00 vs. the Income of €19 200.00 (Figure 3.) for the same sector that did not deploy External Antennas.
Since the capital outlay of External Antenna + Installation is once off, consider the huge difference in Net income over a 48 month period of €105 000.00 vs. €38 000.00 (Figure 3.)
The argument is sometimes raised as to why should the MNO provide External Antennas for those customers that may not needs it but, the calculation shows clearly that supplying each customer with the same basic installation reduces complexity in determining which customer gets issued with an External Antenna and which ones not.
In conclusion it is clear that an MNO providing a FWA service wins in user satisfaction as well as cost benefit in all cases by installing External Antennas for all their customers.