Alpha Omega Wireless Blog

Point to Point Wireless Bridge Through a Glass Window

Posted by Joe Wargo on Thu, Mar 14, 2013 @ 03:37 PM

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.

Wireless through glass

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.

Wireless Glass Shot

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!

Tags: Alpha Omega Wireless, Point to Point Wireless, General, Un-lincesed Wireless, AO Wireless, Wireless 101

Licensed Point to Point Wireless Bridge Solutions Come of Age

Posted by Joe Wargo on Fri, Dec 14, 2012 @ 04:03 PM

Licensed point to point wireless bridge systems are now becoming more of the norm rather than the exception. Historically, everyone turned to fiber as their primary choice for point to point data connectivity. Now with the recent changes to FCC regulations on point to point microwave, also referred to as “ptp wireless”, the opportunity to create high-speed bandwidth wireless point to point connections are easier than ever.

                                          Wireless 2 0        Wireless Roof Top

Point to point wireless backhaul, often referred to as fixed wireless backhaul or wireless Ethernet bridges, is a great solution for creating network connectivity between locations. Wireless point to point can be used as primary or redundant wireless networks. Wireless backhaul can be used for establishing data and voice network connections from building to building, communication tower to communication tower, field locations to a network presence, connecting network fiber segments, or last mile connections, etc. Point to point wireless Ethernet bridges can also be used for connecting devices on to networks, like IP video cameras, SCADA devices, etc.

Licensed point to point wireless backhaul is far easier and cheaper to deploy than fiber (See “Wireless Backhaul Makes Financial Sense”). Costs of running fiber can be upwards of $100K to $1M a mile. Point to point broadband wireless, especially point to point licensed wireless networks can now compete with fiber, not only in price per Mbps, but in performance and reliability. Plus there are many advantages of owning a private network, like security, support, and reliability.

The FCC has opened up the ability to use larger licensed point to point microwave spectrum channels (like in the 11GHz point to point licensed microwave spectrum). They also have allowed for higher ptp wireless modulation schemes up to 1024QAM at channel widths up to 80MHz wide. Plus with recent use of XPIC systems it is much easier to get licensed point to point microwave frequencies on a given path. (See: “Licensed Microwave Wireless Backhaul” for more information about point to point licensed microwave systems or “Licensed Microwave vs. Unlicensed Outdoor Wireless” for more information about the different types of point to point wireless systems.)

Today licensed point to point microwave radios can provide interference free GigE full duplex connectivity at 99.999% predictable reliability, and with <2ms latency. Multiple point to point microwave radios can be installed together and configured for even higher bandwidth, while providing compete failover redundancy, using 2+0, 3+0, and 4+0 configurations. Links upwards of 30+ miles can be achieved. Even further distances can be installed using a wireless repeater from a tall building roof top or communication tower.

The one disadvantage of point to point wireless bridge systems is the need for line-of-sight from antenna to antenna (aka “LOS”). This can be an issue with low lying buildings and trees. In those cases using a communication tower for a wireless repeater can solve the issue in many cases. Communication towers are all over the place. There are many publicly traded companies that offer lease space for point to point microwave antennas. If there is the ability to find land right use communication towers are relatively inexpensive to have installed. Point to point wireless backhaul has a rapid ROI (typically less than 6 months with no reoccurring costs). Adding a tower into the solutions may only add 3 to 4 months until the CAPEX ROI is achieved. Free standing towers at 100ft in height can be installed from $65,000 to $85,000. That is not much money when you look at the big picture.

Many countries around the world have leapfrogged the United States when it comes to wireless backhaul and taking advantage of wireless bandwidth. Here we have relied on fiber as the top pick for broadband, but the cost per mile and the issues with permitting and right of way access present an ongoing challenge, especially in rural America. Using point to point wireless bridges can expand the reach of high broadband bandwidth where fiber is a challenge.

Whether a private organization, an agricultural group, government agency, utility, healthcare organization, or education facility point to point licensed wireless maybe a perfect alternative to fiber or lease lines. 

Tags: Point to Point Wireless, Licensed wireless, Wireless Industry, Wireless 101

Wireless Backhaul Used for Live Concert Events by SXSW

Posted by Joe Wargo on Tue, Mar 22, 2011 @ 09:58 PM

What do you do when you need to provide Internet connectivity for one of the largest live music and film festivals in the world? You build out a wireless backhaul network using point to point microwave!

SXSW2011
At the 2011 SXSW (South by Southwest) Film and Music Festival tens of thousands of people from around the world swarmed to Austin, TX to experience the latest in film and see the over 2000 bands that played live at over 200 venues. The SXSW event merges film, music and technology all in one place. Technology is playing an even larger role at SXSW. It was the place that Microsoft launched their new IE9 platform.

Austin was filled with members of the media reporting on the events and who's making news in the film and music industry. Bloggers are found on every corner writing about who's playing and getting signed to large record labels. Live concerts were broadcasted live over the Internet. Bands like the Foo Fighters, Duran Duran, Blue October, Kid Rock, Snoop Dogg, Bob Schneider, Crystal Bowersox, and many others showed up without much warning to perform.

In years past, one of the biggest complaints was the lack of broadband connectivity, that's if you could get connected at all. With so many people in such a concentrated area many of the cellular networks get overloaded and come to a crawl. Add to the fact that there is now a 1 to 1 or even a 2 to 1 ratio of wi-fi enabled devices to people. Laptops, iPhones, iPads, and all the other smartphone devices were present everywhere. This year SXSW wanted to make sure that they could enhance the attendees experience by bringing wireless bandwidth to the people.

SXSW could get a large (GigE) Internet pipe to their corporate office but couldn't get connectivity to the major facilities by the local telecommunication providers. With months of planning At&t, Time Warner, Verizon, etc. failed provide a temporary wireless solution. So they turned to Alpha Omega Wireless to solve the problem. We were able to build out a high bandwidth, point to point wireless backhaul network from their facility to some major venues around Austin. Even though the fiber providers couldn't do it with months of advanced notice the wireless installation of SXSW's wireless broadband was deployed in days.

Wireless Backhaul at SXSWBecause of the bandwidth demand we used full duplex microwave radios, such as SAF Lumina licensed microwave and 24GHz unlicensed wireless ethernet bridges, BridgeWave 60GHz wireless links, and a few unlicensed wireless bridges for specific events. Most venues were able to get 100Mbps full duplex wireless connectivity.

Wireless backhaul used for the core network distribution and last mile wireless used to provide bandwidth to special event venues gave SXSW a lot of flexibility and the ability to provide wi-fi to attendees. Once the event was over the equipment was removed as if it was never there.

Tags: Alpha Omega Wireless, Point to Point Wireless, General, Wireless Industry, wireless video, Wireless 101

Wireless Backhaul Makes Financial Sense

Posted by Joe Wargo on Fri, Sep 24, 2010 @ 05:06 PM

Wireless backhaul, often referred to as fixed wireless backhaul or wireless Ethernet bridges, has become a standard for creating network connectivity between locations. Wireless backhaul can be used for establishing data network connections from building to building, field locations to a network presence, connecting network fiber segments, or last mile connections, etc. Wireless Ethernet bridges can also be used for connecting devices on to networks, like IP video cameras, SCADA devices, client devices, phones, two-way radio / pagers, etc.

Wireless backhaul can be in the form of point to point wireless, point to multipoint wireless, or wireless mesh configurations. Wireless bridges can be licensed microwave links or unlicensed wireless Ethernet bridges. A licensed microwave link or wireless Ethernet bridge can provide throughput as low as 10Mbps up to GigE full duplex (with gigabit wireless).

Wireless Ethernet bridges, allow you to eliminate reoccurring costs of leasing fiber from telecommunication companies, eliminate the cost of additional head end equipment, and AES encryption hardware devices. Wireless Ethernet bridges preserve native IP throughout the system. Because you own the microwave link connection and not lease it, ROI is maximized with a low CPEX. You also gain the peace of mind of having control over your own infrastructure.

Take for example the cost to lease a DS3 (45Mbps) connection through a carrier. A typical scenario is that it costs roughly $4000.00 a month with a 3 to 5 year contract. Over three years that’s $144,000.00! Let’s not forget that it also typically takes 3 to 6 months to provision.

Now for comparison, let’s look at a point to point wireless Ethernet bridge using a licensed microwave radios. Although you can install a 50Mbps full duplex (100Mbps aggregate throughput) wireless bridge, most systems are typically purchased at 100Mbps full duplex (200Mbps aggregate throughput) because there just isn’t much cost differential between a 50Mbps and 100Mbps full duplex licensed microwave link. It’s typically the same radio system and just software throttled. Most licensed microwave radios are capable of 366Mbps full duplex (732Mbps aggregate throughput) and 60GHz and 80GHz millimeter wave is GigE full duplex.

A typical 100Mbps full duplex licensed microwave link, which can be installed in several days rather than 4 to 6 months like a DS3, would have a CAPEX of $20,000.00 to $30,000.00 depending on the frequency and distance. Say you add in a 5 year advanced replacement manufacture warranty and annual support from the integrator at a cost of $15,000.00. That’s roughly $45,000.00 compared to $144,000.00. That gives you an ROI of roughly 11 months. Plus you have over double the bandwidth!

Wireless ROI

As you compare higher bandwidths like leased 100Mbps or gigabit fiber the ROI is increased even further. Most GigE wireless backhauls have an ROI of 3 to 4 months. That’s it. No more reoccurring costs because you own it. If a wireless Ethernet bridge is properly engineered and the wireless installation is done by a professional wireless integrator a point to point wireless backhaul can provide greater security over leased lines and give 99.999% reliability (meaning <5min of predictable outage a year). Most telecommunication companies can only guaranty 99.9% on a SLA because they know they’ll have network outages throughout the year.

Tags: Point to Point Wireless, Licensed wireless, General, Un-lincesed Wireless, Wireless Industry, Point to Multipoint, wireless mesh, Wireless 101

Wireless Backhaul Can Prevent Network Outages

Posted by Joe Wargo on Fri, Aug 27, 2010 @ 05:09 PM

Wireless backhaul in the form of point to point microwave - licensed microwave links or unlicensed wireless Ethernet bridges, point to multipoint wireless Ethernet bridges, or wireless mesh network infrastructures can provide up to 99.999% reliability and keep you up and running when your telecommunications provider fails you.

Redundant Wireless backhaul Do you ever experience downtime on you network due to outages with your telecommunications provider, such as: AT&T, Verizon, or Comcast? What does a network outage cost you organization in dollars and man hours due to lack of productivity and internal communication or with clients? What do you say? This never happens? Think again!

You think you’re safe because you have a point to point fiber connection from your telecommunications vendor? Read my article “Outdoor Wireless Bridges or Fiber, Which Do You Trust.” What if you use an MPLS network, doesn’t that provide you failover redundancy? What about having different carriers for a backup connection? Or what about using cellular modems as a last result? Aren’t you protected by having redundancy? Not really!

The true fact is that the major telecommunications companies have outages all the time. December 11th, 2009 San Francisco experienced a several hour AT&T outage. July 21, 2010, AT&T Wireless had a regional outage for hours in NC. On April 9th, 2009 Santa Clara County, CA declared a local emergency when someone intentionally cut an underground fiber optic cable in South San Jose taking out cellular, internet, and phone usage to AT&T, Verizon, and Sprint/Nextel customers. This affected multiple cities. A local hospital had to cancel surgeries due to the emergency. Recently, Union City, CA experienced a city wide outage when central office went dark. All voice, internet, MPLS, cellular, etc. was out for almost 10 hours.

So what happens when you have no cellular, internet, data, or voice connectivity?  For some organizations they have critical operations that have to be monitored so they have to be physically manned if the network goes down. What’s the cost to deploy people to remote sites or work overtime during the middle of the night? What about lost data? Some organizations can run into the millions of dollars an hour during a network outage.

Too often organizations fail to ensure their communications, both data and voice, are protected by not having appropriate redundancy or just flat out relying on a third party telecommunications vendor. Many times those who have a redundancy solution in place don’t have “True Redundancy.” Many overlook their WAN connections or have single point of failures in using the same medium (such as fiber), or taking the same external routes (out the same conduits from their MPOE), or have unknown points of failure by relying on third party telco providers’ networks. You can have MPLS but if you first connect through a local central office and that CO goes dark there is an issue. Even with backup power central office have gone dark (recently in Union City, CA) and fiber lines have been cut (San Jose, CA).

Licensed Microwave LinkWireless backhaul connectivity, both point to point wireless links and point to multipoint wireless bridges, provide an avenue for extremely reliable primary connections and for creating “True Redundant” network paths and connections. With both unlicensed wireless Ethernet bridges or licensed microwave links, an organization can create a completely separate stand alone network and eliminate the dependency on third parties equipment and facilities, and remove the risk of failure of fiber cuts off site and out of an organizations control.

So why own your own wireless backhaul network? Wireless backhaul, with proper wireless path engineering, the use of the right outdoor wireless backhaul equipment, and proper wireless installation can provide truly reliable networks. See articles, “Is Wireless Reliable? - The 5 Misconceptions - Part 2” and “Outdoor Wireless Installation Done Properly.”

Wireless backhaul can have multiple advantages. Wireless networks can be used for primary or redundant links. Throughput can match or even exceed that of a leased line from a telco. You can get connectivity where you can’t get it from a telco for last mile solutions. Wireless backhaul typically has an extremely low ROI and can eliminate reoccurring lease line costs. Wireless installation can be done in days compared to months of provisioning time from a telco. Also with wireless backhaul you have complete control of your network. Even in the event of equipment failure wireless nodes can be restored quickly by simply hot swapping the radio communications equipment.

That’s right no more trouble tickets from some call center agent in another country!

Tags: Point to Point Wireless, Licensed wireless, General, Un-lincesed Wireless, Wireless Industry, Point to Multipoint, wireless mesh, Wireless 101

Wireless Backhaul Communication Towers are a Great Investment

Posted by Joe Wargo on Sat, Aug 21, 2010 @ 03:49 PM

Wireless backhaul, also known as fixed wireless, technology has become a standard means of creating a data communications link between locations. Microwave radio links can be used to make data connections from building to building, to connect remote field locations to a network presence (also known as last mile wireless), connecting network fiber segments, and for connecting network devices (like IP video cameras, SCADA devices, client devices, phones, two-way radio / pagers, etc.) to networks.

Wireless backhaul can be in point to point wireless, point to multipoint wireless, or wireless mesh configurations. Wireless bridges can be licensed microwave links or unlicensed wireless Ethernet bridges. A licensed microwave link or unlicensed wireless Ethernet bridge can provide throughput as low as 10Mbps up to GigE full duplex (with gigabit wireless). There are many wireless backhaul radio platforms offering a solution to just about any application. Wireless backhaul systems can provide 99.999% reliability. A Point to point wireless Ethernet bridge or licensed microwave link can enable high capacity wireless backhaul connections from less than one mile to more than 50 miles, without performance degradation. Licensed microwave links and unlicensed wireless Ethernet bridges enable carrier class delivery of IP services with full wire-speed performance. Typical latency on a wireless Ethernet bridge or licensed microwave link is under 1ms.

communication towerEven though there are some outdoor wireless radio systems that can do non-line-of-sight (“NLOS”), the majority of wireless backhaul requires line-of-sight (“LOS”) with proper Fresnel Zone clearance to properly operate. This means the transmitting and receiving antennas most be able to see one another with any obstructions. In most cases this requires mounting the antennas on a structure with adequate height to create LOS.

Many times when doing a point to point microwave link from one tall buildings roof top to another’s it can be easy to have LOS.
Sometimes this is not possible. Putting a antenna mast on a roof top can sometimes be sufficient. Other times it may become necessary to construct a communications tower. The first reactions that come to a client’s mind when a wireless installation vendor says a tower need to be built is no way. Several misconceptions arise. Towers are too expensive, unsightly, and are a huge construction project. Reality is that none of these are true.

Communication towers are relatively inexpensive to have installed. Leasing high speed bandwidth form a telco or installing dark fiber is extremely expensive. Point to point wireless backhaul or creating point to multipoint wireless Ethernet bridges for last mile connections have a rapid ROI (typically less than 6 months with no reoccurring costs). Adding a tower into the solutions may only add 3 to 4 months until the CAPEX achieves and ROI. Free standing towers from 40ft to 80ft in height can be installed from $15,000 to $35,000. That is not much money when you look at the big picture.

Build it and they will come! Communication towers are typically built for an initial solution but can offer great potential for future wireless backhaul projects. The tower may have been built to accommodate a point to point wireless bridge like a licensed microwave link between two locations. Now in place it may be used for other wireless Ethernet bridges or point to multipoint last mile wireless bridge connections. Odds are that if you needed to build a tower to gain some height in a geographical area other may need some height too. Leasing opportunities can come knocking on the door. Tower can create a great source of re-occurring revenue for an organization by leasing antenna space off to other parties that need a repeater location or leasing space to the mobile carriers, like At&t, Verizon, Sprint, Clearwire, etc. These opportunities can pay for the tower itself.

Roof top towerThe fact is that there are tower all around us and we just don’t even notice them. Microwave communication towers tend to blend into the skyline. So many times we hear about cosmetic concerns when it comes to mounting antennas on buildings but the fact remains that they are all around and no one ever notices them (unless you are in the wireless industry and pay attention to them). Many are less obtrusive that satellite TV dishes everyone mounts on their homes!

Microwave tower have been manufactured in ready to deploy configurations and even come with approved engineered design drawings making the permitting process simple. Communication towers used for wireless backhaul can typically be installed within a few days and offer a long term solid structure for mounting wireless backhaul antennas and equipment.

Tags: Point to Point Wireless, Licensed wireless, General, Un-lincesed Wireless, Wireless Industry, Point to Multipoint, Wireless 101

Choosing the Right Outdoor Wireless Vendor

Posted by Joe Wargo on Fri, Aug 13, 2010 @ 05:11 PM

Choosing the right outdoor wireless vendor is critical for the success of a wireless backhaul project, whether it’s a licensed microwave link, unlicensed wireless Ethernet bridge, wireless mesh, WiMax, point to point wireless backhaul, or point to multipoint wireless Ethernet bridges. Not all wireless vendors or wireless installation companies are the same. Too many companies and people claim to be RF Engineers or outdoor wireless backhaul experts without ever having any real world project experience.

Wireless Integrator

Some wireless vendors are just “box movers” with a sole purpose to sell hardware. These companies typically do not have any field experience with wireless installations, wireless site surveys, or spectrum analysis. They may be able to do wireless path calculations using some software programs, but the information they use for the outdoor wireless network design is based on information they receive from the client. Because they lack any real world filed experience they tend to miss the fine intricacies that can make or break an outdoor wireless backhaul project. They also typically try and push to the customer whatever product makes them the best margins.

Some “so called” wireless vendors come with the IT networking background. They too lack any real world outdoor RF or microwave experience. They may focus on a conceptual wireless network design but have no understanding on the details of what it takes to actually install and maintain an outdoor radio system. Everything looks great on paper but when it comes time to install the system and make it work everything goes south when there is a huge groove of trees or buildings in the way! These companies might be good at the network integration portion of a project but have no clue to the way outdoor wireless systems perform in the field or what it takes to properly do a wireless installation.

There are some great outdoor wireless vendors that have a ton of outdoor radio system experience but lack any knowledge of integrating the wireless infrastructure to the client’s network.

Wireless antenna installationA true outdoor wireless integrator will have in house experience with all aspects of an outdoor wireless backhaul system. A good wireless integrator will know how to properly design a wireless backhaul network, perform accurate wireless path calculations, and understand exactly what it takes to deploy a wireless backhaul network.

The good companies have experience with point to point unlicensed wireless Ethernet bridges, licensed microwave links, wireless mesh, point to multipoint wireless bridges, etc. These companies know the industry and can make appropriate recommendations on whether unlicensed wireless Ethernet bridges or licensed microwave links are right for the backhaul solutions or which is the right fit between wireless mesh and point to multipoint wireless bridges. Good wireless vendors also understand IP networking and can integrate the outdoor wireless system into the client’s network.

The good outdoor wireless integrators have experience working with towers, poles, and on roof tops. They know exactly what the mounting and power solutions need to be and what goes into the proper wireless installation of the radio equipment. True wireless integrators can properly plan, price, and insure success of an outdoor wireless backhaul project.

What about after the project? Many “so called” wireless vendors come across knowledgeable about designing a radio communication system or claim that have a lot of wireless installation experience. The question to ask is if something goes wrong or there is an issue down the road, will the wireless vendor be there for support. Did the wireless vendor rely on subcontractors for the project? Will they need to coordinate with subcontractors to support the client’s system? What will they charge to perform support if they do need to rely on a sub? These are important questions. The “so called” wireless vendors can’t control if their subs will be around in the future or what they may charge. What about the amount of time it would take to get different companies involved and dispatched?

A good wireless integrator performs all the work themselves and does not rely on subcontractors. They can take full ownership of the outdoor wireless system and can support it.

Wireless backhaul, whether you are talking about wireless mesh, WiMax, point to multipoint wireless, or point to point wireless backhaul, systems can function with extreme reliability and predictability with proper wireless network design, wireless engineering, and a quality wireless installation. The mobile wireless carriers take this matter critically and waste no expenses on ensuring their systems are installed properly. Any down time can cost them tens of thousands of dollars. The craziest thing is when organizations are willing to rely on wireless technology for their primary connectivity but pinch pennies by choosing the cheapest and many times least experienced wireless vendor or wireless installation companies for their projects.

Tags: General, Wireless Industry, Wireless 101

Understanding Microwave Communication Frequencies

Posted by Joe Wargo on Sun, Jun 27, 2010 @ 03:39 PM

The term "Microwave" is a broad term that covers the UHF (Ultra High Frequency with frequencies between 300MHz and 3GHz) to the EHF (Extremely High Frequency with frequencies between 30GHz to 300GHz). Licensed microwave links and unlicensed wireless Ethernet bridges typically operate in the SHF (Super High Frequency with frequencies between 3GHz to 30GHz) and the EHF bands.

Microwave Communication Tower

A general rule of thumb is that lower the frequency the farther the signal will travel. Also lower frequencies the lower the throughput and higher the frequency the higher the throughput. Again this is in general terms and depends on the wireless radio hardware used.

The terms "unlicensed wireless bridge" and "licensed microwave link" refer to the radio frequency spectrum characteristics set by the U.S. Federal Communications Commission ("FCC") or equivalent national government regulatory body. Licensed products require regulatory approval before deployment while license-exempt products can be deployed without any regulatory approval.

Licensed microwave link frequencies used for wireless backhaul in a point to point wireless backhaul operate 6GHz, 11GHz, 18GHz, 23GHz bands and the 80GHz millimeter wave E-band. Unlicensed wireless Ethernet bridges, used in point to point wireless bridges, point to multipoint wireless bridges, or wireless mesh configurations, typically operate in 900MHz, 2.4GHz, 5.3GHz, 5.4GHz, or 5.8GHz frequencies. There is also the 60GHz millimeter wave band that is used for point to point gigabit wireless bridges.

There are registered frequencies that many think are licensed but are actually unlicensed, like the 3.65GHz WiMax band used for point to multipoint wireless backhaul and the 4.9GHz Public Safety band. These registered bands do provide some protection against interference but only require local users to coordinate with one another on frequency channel coordination. This is often confused by Public Safety organizations that think the 4.9GHz band is for exclusive use by local law enforcement. Anyone can register the use of the 4.9GHz band as long as it's used for some form of public safety, such as video backhaul.

BridgeWave Proxim ResundancyLicensed microwave wireless radio systems are typically built and designed for long term solutions. Point to point licensed microwave links are true fiber replacement systems and offer full duplex wireless communications for both Ethernet and TDM. The licensed wireless bridge hardware is designed to provide carrier grade performance (high bandwidth and low latency). Because a microwave link is licensed and is not to inject and interference on other licensed microwave backhaul operators in the area they must have LOS (line of sight) and not cause heavy multipath. This is a common question of why licensed microwave radios don't use OFDM or MIMO and why they can't be used in NLOS (non line of sight) applications. In a NLOS wireless link application unlicensed wireless backhaul radios that use OFDM or MIMO take advantage of multipath for their connectivity.

Microwave communication using unlicensed wireless Ethernet bridge systems have been an extremely popular choice for outdoor wireless backhaul. The unlicensed spectrum of 5GHz (5.3GHz, 5.4GHz, and 5.8GHz UNII bands) became a primary selection by many end users and outdoor wireless installation VAR's, because of their flexibility, cost effectiveness, rapid ROI, and quick deployments. Many outdoor wireless manufactures started introducing "value line" point to point wireless Ethernet bridges using 802.11 chipsets. Basically, the same radio boards found in Wi-Fi access points put into an outdoor enclosure and using outdoor wireless antennas. The new 802.11n based wireless backhaul radios use OFDM and MIMO taking advantage of multipath, especially helpful in NLOS (non line of sight) applications. The major issue with unlicensed wireless Ethernet bridges is potential wireless interference.

Tags: Point to Point Wireless, Licensed wireless, General, Un-lincesed Wireless, wireless mesh, Wireless 101

Understanding Fixed Wireless Backhaul Configurations

Posted by Joe Wargo on Wed, Jun 23, 2010 @ 03:14 PM

Wireless backhaul, also known as fixed wireless bridges, has become a standard means of creating a microwave communication between locations; whether building to building, last mile wireless to connect remote locations to a network presence, or for connecting devices like IP video cameras, access control, SCADA devices, client devices, or phones to networks. Wireless backhaul can be deployed in several network configurations.

Fixed Wireless RepeaterA point to point wireless bridge is when only two microwave radio ends are bridged together to create a single wireless network path. Point to point wireless links are an ideal complement or replacement to leased lines and fiber. A point to point microwave link is used to create a wireless bridge network between two buildings to connect LAN connectivity or for creating a microwave link between two towers to join two WAN network segments together across large distances. Point to point wireless bridges can be licensed microwave links or unlicensed wireless Ethernet bridges and can provide throughput as low as 10Mbps up to GigE full duplex (with gigabit wireless).

Licensed microwave links used for point to point wireless backhaul operate in the 6GHz, 11GHz, 18GHz, and 23GHz frequencies and provide true full duplex wireless Ethernet and TDM communications. Licensed microwave links can provide up to 366Mbps full duplex or 732Mbps aggregate throughput using a single radio unit. Dual radio units can be combined on a single antenna to provide double the bandwidth and complete failover redundancy.

A few exceptions are the 24GHz microwave links that are unlicensed but work just like the licensed 23GHz microwave links and provide the full duplex connectivity and the 60GHz millimeter wave systems that provide up to full duplex gigabit wireless backhaul. There is also the 80GHz millimeter wave E-band that is a registered frequency that is used to provide gigabit wireless links. Unlicensed point to point wireless Ethernet bridges typically communicate in TDD because they use the same frequency channel to talk and listen. They can provide up to 300Mbps aggregate throughput.

Point to multipoint base station

Point to multipoint wireless Ethernet bridges use a hub spoke configuration using a Base Station Unit ("BSU" or "AP") that communicates with multiple Subscriber Units. This is similar to a cellular network where multiple mobile devices talk back to a cell tower location. Point to multipoint wireless backhaul systems are ideal for interconnecting campus buildings, security systems, control systems, IP video surveillance cameras, WISP applications, integrating remote business sites, or installing last mile connections. Point to multipoint wireless bridges operate in the unlicensed wireless frequency bands of 900MHz, 2.4GHz, 5.3GHz, 5.4GHz, or 5.8GHz. Point to multipoint wireless Ethernet bridges can provide up to 300Mbps aggregate throughput.

Wireless mesh configurations are used to create a wireless network where a radio node can communicate with two or more other wireless mesh nodes. Wireless mesh networks offer great redundancy. If one wireless mesh node can no longer operate, all the other wireless mesh nodes can still communicate with each other, directly or through one or more intermediate outdoor wireless bridge links. Each wireless Ethernet bridge link can send and receive messages in a wireless mesh network. Each link also functions as a router and can relay messages for its neighbors. Through the relaying process, a packet of wireless data will find its way to its destination, passing through intermediate links with reliable communication.

Mesh wireless backhaul networks are typically configured in a star topology or can be in a daisy chain configuration. They are used a lot in networks for wireless video backhaul and municipal wireless networks. Wireless mesh radios operate in unlicensed wireless backhaul frequencies like that of point to multipoint wireless bridges and can provide up to 300Mbps aggregate throughput.


Tags: Point to Point Wireless, Licensed wireless, Un-lincesed Wireless, Wireless Industry, Point to Multipoint, wireless mesh, Wireless 101

Unlicensed 24GHz Point to Point Wireless Backhaul Option

Posted by Joe Wargo on Fri, May 28, 2010 @ 09:17 AM

Point to point wireless backhaul can be either a licensed microwave link or an unlicensed wireless Ethernet bridge. The terms "unlicensed wireless" (also called "license exempt) and "licensed microwave" refer to the radio frequency spectrum characteristics set by the FCC or equivalent national government regulatory body. Licensed microwave communication products require regulatory approval before a wireless installation can take place while unlicensed wireless Ethernet bridges can be deployed without any regulatory approval.

SAF Lumnia 24GHz

Most common unlicensed wireless bridges operate in the 900MHz, 2.4GHz, 5.3GHz, 5.4GHz, and 5.8GHz frequency bands. Unlicensed wireless backhaul is susceptible to wireless interference. See article "Wireless Interference - The Effect on Unlicensed Wireless Backhaul." There is also millimeter wave 60GHz band used for gigabit wireless backhaul that is unlicensed. Licensed microwave links typically operate in 6GHz, 11GHz, 18GHz, and 23GHz. See article "Licensed Microwave Wireless Backhaul." There are a few bands like 4.9GHz public safety band and the 80GHz E-Band that are registered with the FCC but are not truly licensed.

Then there is a part of the spectrum that is mostly overlooked and forgotten about. 24GHz is an unlicensed frequency that can be used for microwave communication for point to point wireless backhaul. For a wireless Ethernet bridge, 24GHz offers some great advantages. Because of the ERIP 24GHz is identical to 23GHz band and can be used for shorter range wireless links (typically under 2 miles) but it has tremendous advantages. First it's rarely used so there is virtually little to no wireless interference. Manufactures that make 24GHz microwave communication radios are those that manufacture 23GHz licensed microwave links and use the same carrier grade microwave radio platform adjusted to operate at 24GHz. As a microwave backhaul link systems can do up to 366Mbps full duplex using 256QAM at 56MHz wide channels. That's 720Mbps aggregate throughput!

Like licensed microwave links, a point to point wireless Ethernet bridge in the 24GHz unlicensed wireless band provides carrier grade wireless backhaul. 24GHz wireless backhaul is ideal for point to point wireless bridges in areas where there is a lot of wireless interference. The unlicensed wireless 5.8GHz band is becoming heavily saturated and it's becoming difficult to deploy wireless Ethernet bridges in many areas. Because the 24GHz band is unlicensed a wireless installation of a 24GHz point to point wireless link can be deployed in a day without the need to wait for a FCC license.

There are many applications that need 100Mbps full duplex connectivity or greater. Millimeter wave 60GHz gigabit wireless radios are also great for shorter applications, but not ever client needs gigabit wireless connections. Most 24GHz microwave communication links can be installed as a 100Mbps full duplex wireless backhaul and can be software upgrade up to 360Mbps full duplex (720Mbps aggregate throughput) protecting the CAPEX investment.

If you need a point to point wireless backhaul that can provide 99.999% reliability, need full duplex connectivity, and are worried about wireless interference then take a look at 24GHz!

Tags: Point to Point Wireless, Licensed wireless, General, Wireless 101