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Thanks!
JOE

The drawbacks are the need for greater bandwidth across the IT network and the limitation of CAT-5e to 100m (unless you are using Ethernet extenders). The solution to both problems can easily be solved by the use of wireless networks. With wireless IP video cameras can be deployed virtually anywhere. Bandwidth also becomes a non issue as a wireless network can be scaled easily.

Putting video across wireless can be tricky. To optimize video streaming over wireless, whether we are talking about point-to-point, point-to-multipoint, or mesh networks, some experience and knowledge is needed. First is selecting the right wireless equipment. Many wireless manufactures offer QOS and VLAN tagging capabilities which make for ideal video surveillance configurations, as we typically want our video network to be on a separate subnet than our traditional data and voice traffic.

If you know what you are doing and have a solid background in wireless and IP networks it’s easily done. The problem we see most of the time is the company doing the deployment is lacking in one of the areas. Too often we see installations that have issues because the installer just throw up a bunch of mesh equipment, using omni-directional antennas, hoping for a plug and play situation. What happens is a lot of self interference (along with outside interference) and too much latency on the network. Even though many hardware manufactures would like you to believe their equipment is plug-n-play that’s not how it works in the real world. Someone that is well trained in wireless networks should be used to deploy any such networks so they can be optimized and configured properly.

Understanding IP video is another area we see issues. Many traditional analog cctv vendors just don’t understand IP networks well enough. If your vendor doesn’t understand QOS and VLAN technology they probably don’t have enough experience to deploy a wireless video solution.

Just like wireless hardware not all being the same nor is the IP cameras. Some work well over wireless and some have issues. Choosing the right camera is important. It’s best to make sure before purchasing and deploying any wireless video solution that you have (or at least get confirmation) that the matching of a wireless manufacture’s equipment and a particular IP camera system work well together. My company, Alpha Omega Wireless, deploys a lot of IP video surveillance cameras over wireless networks. We’ll be performing various test of different video cameras on various wireless equipment and will be posting regularly the results. Stay tuned!

Question 3: Is it secure?

Probably the number one question we receive from those that have never truly used wireless for their back haul is if it’s secure. The main driver for this is either because a person has had no experience using wireless, they have read some negative press online about Wi-Fi being hacked, or they have tried to install wireless using SOHO (small office – home office) grade equipment.

The answer is “Yes!” outdoor wireless is extremely secure. Provided that the equipment is designed for outdoor wireless, it is installed properly, and it is configured correctly. Most wireless systems can meet DOD (Department of Defense) specifications for security and HIPPA compliance.

True outdoor wireless systems (e.g. microwave, WiMax, Mesh, etc.) are designed for secure outdoor radio signal propagation. Most all systems, both Consumer grade and Carrier/Industrial grade, have multiple levels of internal and inherent security.

For instance, most systems allow for encryption to be set at 128-bit to 256-bit AES or equivalent, MAC address or serial number filtering, and/or network security naming conventions. Also, many times systems are paired and only allow communications with a known partnered radio. Many of the Carrier/Industrial grade wireless have their own proprietary encryption built in and use various protocols not found in consumer electronic components. Meaning someone can’t just buy something off the shelf that can even receive the signal and/or frequency. As is the case with most licensed microwave systems.

Inherent with properly designed and installed outdoor microwave wireless systems is the fact they they are typically set up as a point-to-point system. This means the radios use directional antennas utilizing extremely narrow beam widths (typical under 3 degrees). The radio signal is also transmitted in a particular polarization plane (e.g. vertically or horizontally) which provides around 25dBm of signal separation. For someone to intercept such a signal they would have to place a receiving antenna directly or extremely close to the path of the original signal. Hard to do if they don’t have access to a tower or roof top where the signal has originated from or in the direct path.

Wi-Fi systems, because they are broadcasted in an omnidirectional fashion and are typically set up by non-industry professionals, have been victims of hacking attacks. Plus the fact that most all portable electronic computing devices and mobile phones have built in Wi-Fi makes it easy for one to have all the equipment they need to find and identify the wireless source (access point). Still if Wi-Fi is installed and configured properly, using best practices, it too can be fully secure. Also, encryption standards continue to increase.

Outdoor systems are completely different that their Wi-Fi partners (provided that one isn’t using Wi-Fi radios for outdoor bridging). Outdoor wireless has been used by the telecommunication companies and the military for decades. System continue to provide increased levels of security.

In comparison to traditional land line circuits, wireless systems can provide a higher level of security. It is not difficult to gain access to a buildings telecommunications MPOE (main point of entry) wiring closet or access to outdoor, ground level, telecommunication vaults. These locations can allow someone to easily tap onto an organizations internal network. I’ve had clients tell me how they are completely secure on their WAN/LAN networks and wouldn’t trust anything but their copper and fiber connections. They often forget that someone can easily plug their laptop into a data jack in their lobby, gain access to their cable infrastructure from neighboring ceiling crawlspace, or  jump on their WAN infrastructure from an outdoor telecommunication  cabinet (which if locked at all can be easily broken into). Note: even with physical land line infrastructure one should use best practices for encryption and security. I’m not saying that WAN/LAN infrastructures are not secure, but in many cases people forget to completely secure their networks. What I am saying is that wireless systems can be just as, if not more, secure than traditional wire/fiber networks.

Question 2: Is it reliable?

Yes! Provided it is designed / engineered correctly, you use the right equipment & frequencies, and it is installed properly.

As with the prior blog on this series Outdoor Wireless and the 5 Misconceptions, Part 1 – Does weather effect wireless?, I stressed the importance of properly designing and installing the right equipment. This will be a common theme throughout the series. Outdoor wireless is different than indoor 802.11 a/b/g/n Wi-Fi that many are accustomed too. Indoor wireless devices take advantage of multipath and are very forgiving due to its short range, high power transmission using typically omnidirectional antennas.

Outdoor wireless, especially when dealing with point-to-point or point-to-multipoint networks, relies on having a concentrated directional signal in order to create the best possible signal and interference negation. This means a specific antenna communicates (sends and receives) with another specified antenna(s).

From “Part 1:” All wireless signals that travel from one antenna system to another experiences some form of “Path Loss“. Properly designed systems use the correct antennas, frequencies, and transmit power (“Tx”) to overcome the Path Loss to get the desired Receive Signal Level (“RSL” measured in dBm). Radios are designed to operate with a certain level of “Fade Margin” that allows the system to operate at a predictable reliability (for most systems 20 to 25dB of Fade Margin is recommended). This means if a system has an RSL of -50dBm and it has a receiver threshold of -72dBm, you’ll have 22dB of Fade Margin or the amount of dB signal strength a system can loose before you will experience errors (referred to as BER – Bite Error Ratio)or loss of connectivity.

Factors that can effect a RSL to fade can be either natural (e.g trees, heavy rain, or wind moving the antenna) or man made (e.g. building built in the path) causing the signal to be partially or fully blocked. Other environmental factors can be interference (an undesired signal in the same frequency from another system) or multipathing caused be reflection off a physical surface, either in the near field or along the path.

Knowing the radio system’s designed threshold one can perform path calculations, combining path loss, predictive modeling (terrain and weather models), system components (antenna and radio gain), etc. Software tools are available to perform the path calculations like: Path Loss or MicroPath.

With path calculations we can determine the predictable reliability of most wireless systems. Important to note you get what you pay for. There are both good and bad manufactured wireless equipment. A properly designed system can achieve 99.999% reliability (<5min of predictable outage a year). This is typically better than any leased Telco circuit’s SLA.

It all comes down to proper planning (design / engineering), proper equipment,  frequency choice, and proper installation. Note: Installation should be done by a licensed professional that understands the key elements of proper radio installation. Trust me. After years of troubleshooting systems that were installed by other so called professionals,  I have seen about 80% of system issues being due to improper installation. So please do your homework on the vendor you use and get reference by both other clients and the manufacture.

Question 1: Does the weather (like rain) effect wireless?

Well the answer is Yes & No!
Technically “Yes” – different forms of weather do have effects on various frequencies.
Reality “No” – if the right frequency and antenna system is properly engineered, designed, and installed a wireless system can provide 99.999% reliability.

The obvious one is wind. Wind in itself doesn’t effect the RF signal but it does put an external force (wind loading) on the antenna system that can cause it to move or come out of alignment. This is pretty easy to understand. The clear answer is to properly install antenna systems to withstand local wind patterns. Most antenna systems are designed to withstand wind gusts up to 110mph (varies by manufacture).

The main question arises with precipitation (e.g. fog, rain, and snow). All wireless signals that travel from one antenna system to another experiences some form of “Path Loss“. Properly designed systems use the correct antennas, frequencies, and transmit power (“Tx”) to overcome the Path Loss to get the desired Receive Signal Level (“RSL” measured in dBm). Radios are designed to operate with a certain level of “Fade Margin” that allows the system to operate at a predictable reliability (for most systems 20 to 25dB of Fade Margin is recommended). This means if a system has an RSL of -50dBm and it has a receiver threshold of -72dBm, you’ll have 22dB of Fade Margin or the amount of dB signal strength a system can loose before you will experience errors or loss of connectivity.

Moisture such as fog, rain, and snow (depending on its water content) adds attenuation to the signal’s path. The amount of moisture is critical to understand here. Fog, although dense, has very low moisture when it comes to its effect on RF signal. With snow it all depends on its density. Snow typically has less moisture content than actual rain. Rain depends on the amount of rainfall (measured in mm/h) and the size of the raindrops. Heavier the raindrops and the higher velocity of rainfall the higher the attenuation. Typical rainfall produces roughly 5.5dB. Again it depends on the amount of rain coming down and the frequency being used.

Also, the amount of attenuation rain can cause depends on the frequency being used. The lower the frequency the less attenuation. The high the frequency the higher the attenuation. To design a system correctly rain modeling is used (along with other Path Loss factors) for calculating the RSL needed to provide adequate Fade Margin necessary for any given system.

So, if a system is designed and installed properly, a wireless system can still produce 99.999% (<5min predictable yearly outage) reliability. Note: amazingly good since most telco’s only guarantee 99.99% reliability on their fiber infrastructure).

Although the mention of various manufactures might take place it is my goal not to promote any such products. Being active in the integration and implementation of outdoor wireless for many years I believe I have a lot to offer in the form of education and discussion. Please join me!