Alpha Omega Wireless Blog

There are a lot of wireless communication radio manufacturers to choose from when designing a wireless backhaul network. A wireless Ethernet bridge can provide bandwidth speeds of a few Kbps to Gbps+ can be achieved.  Today using point to point wireless backhaul, such as licensed microwave communications, can provide over GigE full duplex wireless communications.  Unlicensed outdoor wireless Ethernet bridge systems can provide over 300Mbps wireless throughput. Point to multipoint wireless systems using unlicensed wireless communications can achieve upwards of 300Mbps and technologies like LTE and WiMax can provide over 40Mbps of wireless communications. 

Utilities, such as water (both clean and waste), oil & gas, and electrical, are large users of wireless communication. Utilities typically cover a large geographic service area and have many end points where there is a need for data communications. It becomes physically impossible or at least cost prohibitive to run fiber communications to hundreds of sites that the utilities need communication. Wireless backhaul solves the utilities’ needs and provides them with a means to better monitor and control their infrastructure in the field.

Historically, utilities only needed and used serial communications to monitor field controls, like flow valves, PLC’s and RTU’s, temperature and pressure gages, relays, etc. Over the past several years we have seen that the whole utility industry is migrating to IP based communications for all their field devices and serial communications are going away. So with that many utility organizations have been replacing traditional SCADA telemetry wireless communications with outdoor wireless Ethernet backhaul.

Utilities are building complete wireless backhaul networks to service their territories. Licensed microwave links are being used for a backbone network. Last mile wireless Ethernet bridge systems, like point to multipoint wireless connectivity, LTE, and WiMax are being deployed to wirelessly connect field facilities. Two-Way radio, LTE, and WiMax are being deployed to provide mobility wireless communications. By doing so utilities are making the jump to wireless Ethernet communication to handle their IP networking needs and are also taking the advantage of the higher bandwidth they get with wireless backhaul.

One major problem the utility industry faces is that with so many different wireless Ethernet bridge technologies manufacturers out there many are buying the wrong wireless communication systems. Utilities are usually operating in harsh environments. Weather is always one concern, but many utilities have to contend with various chemicals, EMI (Electromagnetic Interference), and other situations that can cause damage to many of the typical commercial wireless backhaul systems that are used for other industries.

There is specific wireless backhaul manufactured equipment that has been designed to meet the demanding environments most utilities have. Special radio communication systems have been made to handle environments that contain chemicals, have high exposure to salt air, and even to combat EMI in electrical substations.

For licensed wireless backhaul, companies like SAF Tehnika has launched their new Integra microwave communication radio platform. The Integra uses a special aluminum alloy and stainless steel parts that resistant to corrosion. This includes the antenna and mounting brackets. Many wireless bridge systems used for microwave backhaul have the radio in a die cast housing.  If the enclosure is die-casted it means that the metal is melted, which makes it porous. Although all typical die-casted enclosures are covered with special paint, there still are places were the paint ends and water can easily get into the pores and start corroding. Other outdoor wireless system use NEMA type housings for the radio, but the other parts are not protected for harsh environments. The Integra is fully protected from top down.

Siemens RuggedCom has been known for years for making hardened industrial switch components. Their WiMax platform is just as hardened as their networking equipment. The RuggedCom RuggedMAX WiMax platform is specially made to handle the utility environment. The RuggedCom WiMax base stations and subscriber units are specially designed to handle EMI, which is great for Smart Grid applications, and can be deployed within electrical substations and on structures around high voltage, which we see in the Oil & Gas and Water utility environments.

CalAmp DataRadio has a full line of hardened wireless communication products that have been proven in the utility industry for SCADA backhaul. Their VHF/UHF Viper SC+ radio also gives utilities that are slowly migrating from wireless serial communications to IP based wireless communications. The Viper SC+ can be deployed in a hybrid environment giving the utility all the time needed to slowly convert over their PLC’s and RTU’s from serial to Ethernet. Their new Fusion radio is ideal for vehicle nodes providing LTE backhaul along with in vehicle Wi-Fi handoff.

There are a lot of great wireless backhaul systems out there, but when it comes to harsh and challenging environments like those that utilities face, certain considerations must be taken into account. Choosing the right wireless backhaul products, whether licensed microwave communications, last mile point to multipoint wireless Ethernet connectivity, or for wireless mobility applications is vital for long term survivability and reliability. Specially made hardened wireless communication systems are ideal for use by utilities. The right tool for the job!

There is a lot of talk about the push and mandates about modernizing and moving our electrical system to the Smart Grid. The electrical grid in the USA is out of date and doesn’t allow for the use of modern technology to provide more efficient and cost effective power generation, delivery, and consumption of electrical energy. The goal of modernizing our electrical grid by using current technologies is to provide more reliable distribution, improve fault detection and allow self-healing of the network without the intervention of technicians, create greater efficiencies in monitoring and load adjustments based on peak using times and locations, provide greater security to the grid, and to empower the consumer to be able to better manage their usage and costs.

To make the Smart Grid a reality the implementation of modern communication technology needs to be deployed. Technologies such as, smart meters, intelligent thermostats and appliances, real time sensor metering and controls, and remote monitoring all require the use of reliable IP based communication infrastructure networks. The problem is electrical utility organizations’ electrical network (substations and end consumers) covers vast geographic areas. Many of which are not always near readily available fiber connectivity. This is especially true in rural areas. Even in urban areas there is sometimes difficulty in last mile connections where needed.

In order to build out the Smart Grid wireless backhaul plays a vital role and solves many problems by providing necessary high-speed bandwidth for the use of Smart Grid technologies. By the utilities using wireless Ethernet bridge technologies the utilities gain greater security by having a private network, they can also build in wireless redundancy for greater reliability, have quicker implementation time, realize huge cost savings, provide their workforce with wireless mobility, and have the flexibility for future expansion and growth.

Since the utilities have right-a-way access and easements it becomes easy for them to build out a wireless backhaul network using point to point wireless bridges. Fiber equivalent networks can be achieved with licensed microwave backhaul (see more at “Understanding Microwave Communication Frequencies and Point to Point Wireless Bridge Compared to Fiber”). Today a licensed microwave link can provide 6Gbps+ full duplex wireless connectivity. Using a wireless repeater can allow for long distance wireless backhaul. A typical microwave link can be deployed beyond 20 to 30 miles in a single point to point wireless bridge.

With a core high bandwidth microwave backhaul infrastructure, the use of high speed point to multipoint wireless can be deployed for last mile wireless connectivity. Technologies like WiMax backhaul and LTE allow for licensed interference free point to multipoint wireless bridge connections. True usable IP bandwidth of 10Mbps to 100Mbps can be delivered to the field using point to multipoint wireless Ethernet bridge systems. Wireless Mobility can bring high-speed data connections to workforce vehicles allowing for remote access of data files, email, work orders, and VoIP.

Bringing wireless Ethernet connectivity to the grid and to substations provides the ability to not only perform RTU / PLC monitoring and management, but also opens the way for wireless video surveillance and perimeter security, access control, alarm monitoring, remote workforce capability and access, and real time data collection. Most of all, wireless backhaul allows the integration of other third party Smart Grid devices like Smart Meters, remote switching, and SCADA.

Wireless Ethernet bridges bring the necessary infrastructure to Smart Grid technology. The main issue is that electrical organizations are really good at power generation and delivery, but they are not necessarily experts in telecommunications. It’s not best practices for them to build the internal expertise to build or maintain a large complex wireless backhaul network. Recently attending a Smart Grid conference it became apparent that many electrical organizations have relied on manufacture vendors, whose only goal is to move their product, to guide and influence the type of wireless hardware and wireless network topology they are trying to use for their telecommunications infrastructure. This becomes very problematic when it comes to the quality of RF (radio frequency) devices being used and the overall wireless network design.

In order to provide a long-term, reliable, interference free, and scalable wireless infrastructure it is important to use best of breed, carrier grade infrastructure, along with the use of proper frequency spectrum. Also from a security standpoint the proper wireless devices should be used and configured properly. It’s amazing to see how many electrical organizations have deployed value line, Wi-Fi chipset based, unlicensed wireless Ethernet bridges using 900MHz, 2.4GHz, 4.9GHz, and 5.8GHz for their mission critical network. Many of these systems only have a five year mean to failure time rating and are easily effected by wireless interference. These systems are in themselves not bad or lack some quality, but they fit where they fit and the Smart Grid infrastructure may not be the best use of these unlicensed wireless Ethernet bridge systems.

Electrical utilities have a lot of licensed microwave spectrum available for their use for free or at a very low cost basis. On the flip side many microwave radio systems are built for true full duplex operations, operate at the lowest possible latency, run interference free, and are built for a 20+year life cycle. There is also hardened point to multipoint wireless systems and SCADA telemetry radios designed for EMI protection precisely for use around high voltage applications. 

As with any technology there is value level and enterprise level equipment and software. For mission critical wireless networks there is a large distinction between the quality, performance, and reliability of the two. Smart Grid implementers need to receive more education and proper knowledge transfer from the wireless backhaul industry so that the right business choices can be made on behalf of the country’s critical electrical infrastructure and ultimately the end consumer.

When we think of wireless backhaul and microwave communications we typically think of a point to point wireless bridge that is from communication tower to another tower or building rooftop to another building rooftop. In most all cases for wireless point to point microwave backhaul to work there needs to be line of sight (“LOS”) from one antenna to the other. Some other important factors for a point to point wireless bridge to function correctly is to have proper Fresnel Zone clearance and calculated system gain.

In order to make sure a wireless point to point link, whether you are talking about a licensed microwave backhaul or a 5GHz unlicensed point to point wireless Ethernet bridge, will function properly and have predictable reliability a proper wireless network design and path calculation needs to be performed. By performing a quality (radio frequency) RF path calculation we can determine the Free Space Path Loss and overall wireless system gain based on a particular wireless radio system’s receiver sensitivity threshold. This helps determine frequencies that can be used, output power, RSL (received signal level), polarizations, antenna sizes, and antenna heights. The other factor in designing a point to point wireless bridge is to take into account the signal to noise ratio (the incoming signal quality level over any external frequency noise / interference).

With a typical outdoor point to point wireless link it is easy for a wireless installation company to perform all the necessary path calculations and engineering to design a wireless point to point link with 99.999% predictable reliability (<5min of predictable outage a year). But what happens if you don’t have roof rights access to do a wireless installation on the building’s roof or there is no way to cable from the network room / IDF to the roof? Yet from the building’s window you can look out and see the other end clear as day with good LOS. This happens in the enterprise world where a company may occupy a certain floor of a high rise but can’t get roof right access either because of physical challenges or lease contract issues. Why not just put the antenna behind one of the windows?

Shooting a point to point wireless backhaul through glass is not as easy as it may seem. Wireless bridges are in essence sound waves that operate in frequencies that humans can’t obviously hear. Most all glass used in building construction have some sort of sound attenuation (whether just buy the materials in the glass or on purpose to block out outside sound). In the past most glass windows had lead or other metallic compounds in them. Newer windows use a special sound attenuation film to make the inside more quite. Sometimes this glass also uses special films for polarization to block sun glare.  This attenuation causes the signal quality of the point to point wireless system to be degraded in the form of signal loss.

Windows can also have a reflective property that can cause the wireless bridge to bounce the TX (transmit) signal back into itself causing self-interference and distortion on the radio system. When this happens we see a lot of errors on the network as BER (Bit Error Ratio), Jitter, and CRC errors. This can also over time damage the wireless point to point radio end.

So can it be done? Yes! Over the years we have successfully done wireless installations from behind glass and recently did a critical point to point wireless backhaul at SXSW for a major video streaming event. How did we do it? First we took into account all the possible issues as mentioned above. The first step was to calculate the link budget by doing a detailed path calculation by building in the possible loss due to the attenuation of the glass. Because the link had to be installed using an unlicensed wireless Ethernet bridge we decided to use a MIMO (dual polarization radio that uses both vertical and horizontal polarized TX/RX signals).  In the recent case the shot was very short (less than one mile) and the environmental noise in 5.8GHz was extremely high. We decided to use 5.3GHz band that operates in DFS (dynamic frequency selection – basically channel hopper) in the USA.  Then comes the fun part of the installation. We had to play with the polarizations of each end’s antennas, adjust the power output levels on each side separately, and move the radio end behind the glass back and forth from the glass to find the optimum distance of the antenna from the glass.

There are other radio specific settings that can be applied to help the radio from getting false radar detection (which is a requirement of the FCC that causes the radio to jump channels and lock out various frequencies if it sees a DFS channel signal from another source. This happens when the glass reflects its own signal back into itself out of phase. The system needs to be adjusted so that it doesn’t think its own signal is from another outside source. If the 5.8GHz bad was clean of outside interference you still need to adjust so that the radio doesn’t take on errors.

At the end of the day putting one end of the wireless point to point system behind glass allowed over 100Mbps of bandwidth to be used for the event. Time and material costs were saved by not having to run fiber (due to the length of the cable run to the nearest IDF (network closet) to the roof along with power. It is not racommended to shoot point to point wireless through a glass window and it is always Best Practice to go from rooftop to rooftop, but sometimes its the only option. It takes a lot of planning and back and forth testing, but if the wireless installation is done properly shooting wireless backhaul through glass can work!

As a country we have relied on fiber communications as our primary means of wide area network connectivity. Fiber though is extremely expensive to provision due to right away access, permitting, construction, labor, and cost of material.  Meanwhile a lot of other countries have leap frogged the USA by deploying fixed wireless microwave communications. Many countries around the world are deploying wireless bridge microwave backhaul as their primary backbone telecommunications network. The costs of deploying a point to point wireless bridge can have a ROI of less than three months compared to even leasing fiber that is pre-existing.

Wireless backhaul can be deployed in a matter of weeks if not days. Wireless bridges such as unlicensed 5.8GHz point to point wireless and point to multipoint wireless, in 5.8GHz and 3.65GHz WiMax can be purchased off the shelf and installed in a few days. Licensed microwave communications in the form of a point to point wireless bridge, also called fixed wireless bridges, can be obtained and installed in a few weeks. (see more information "Understanding Fixed Wireless Backhaul Configurations")

With advancements in technology and newer regulation from the FCC, wireless Ethernet bridge systems can deliver over GigE (more than 1Gbps full duplex) throughput. Equivalent to that of fiber. A fixed wireless microwave link can go upwards of 50 miles. If proper wireless system design is done, a fixed wireless Ethernet bridge can provide a predictable reliability of 99.999% uptime. That's less than 5 minutes of predictable outage a year.

Most people don't think about the fiber once it leaves their building or know the path it takes. Fiber in urban areas runs inside sewer lines, underground conduits, and aerial on phone and light poles. In rural areas fiber mostly runs aerial along telephone and electric poles. Ever drive down a road and see a bunch of wood telephone poles leaning from side to side? Well that might just be the fiber your network is running on.

Ever question how long it takes for a telecommunications company to do a truck roll to repair a cut fiber? If it's a clean break fiber can sometimes be fusion spliced back together. In most cases where a fiber pole goes down or gets ripped out by a backhoe, the fiber gets stretch and has to be replace but cutting it at two ends and a new piece fusion spliced back in. This can take hours if not days to accomplish. What would be the cost to your business if that occurred?

Microwave communication can be in the form of a point to point wireless backhaul, a point to multipoint wireless bridge, or a mesh wireless Ethernet bridge. If a microwave radio fails it can be swapped out in the matter of minutes (provided a spare is maintained). After an earthquake or other natural disaster, a wireless system can be realigned immediately getting communications back up and running.  The biggest concern with wireless backhaul is the potential for wireless interference. Using a licensed microwave link can solve any interference concerns.(See more information "Wireless Backhaul Can Prevent Network Outages")

In order to get broadband across the USA at any reasonable time frame and at realistic costs we must turn to wireless backhaul technology. Fixed wireless, using both point to point wireless bridges and point to multipoint wireless (LTE and WiMax) can help expand our wide area network reach with carrier grade performance and reliability.