Treese Communications, Inc. is a full-service telecommunications company committed to staying up-to-date with the latest technologies to help its customers. Treese technicians have more than 50 years combined experience in both voice and data communications with more than 4,000 hours of formal training. So, when there is a challenge presented to them, they rise to the occasion.

An interesting project Treese recently took on involved Franklin Industries in Pennsylvania, a mill that rerolls used rails from the railroad and heats them to roll a wide variety of products. This particular company turned to Treese Communications, Inc. to add computers and link 4 new locations to their existing data network.

Not So Meshed
The Franklin Industries plant was built in 1901, so implementing new wiring would not be an easy task. After looking at the site, it became apparent to Treese that deploying fiber to this location would be very costly because of the age and layout of the plant. In addition, trenching long distances under railroad tracks in a heavily traveled area would have been very disruptive and costly to their business.

Bill Treese of Treese Communications developed a solution that blends the mill’s current network with an innovative and industrial-grade wireless solution. Given the layout of the site and the cost of running fiber, Bill concluded that an Ethernet wireless solution would be the best way to go.

Capitalizing on the strength of wireless mesh architecture, he worked to deploy a technology that creates a wireless infrastructure enabling the simultaneous streaming of data, video, and voice.

Nodes in a wireless mesh network are powerful devices that run advanced mesh routing algorithms designed to evaluate and select the optimal path for every transmitted packet in real time. The dynamic mesh routing algorithm allows the routing of packets and video streams around obstacles, sources of interference or low-quality links, increasing reliability and flexibility at the same time.

Routing in a wireless environment is conceptually similar to routing over the Internet but is different in terms of evaluating the quality of a particular path. While Internet routing is based on minimal hop count, the quality of wireless links in a mesh network is crucially important.

Researchers at the Massachusetts Institute of Technology (MIT) recently discovered that minimum hop count is not effective for wireless routing. Rather, a metric involving link-quality measurements is needed to create reliable wireless mesh networks. This discovery broke most of the layered abstractions developed by the inventors of the Internet in the 1980s and 1990s, and established new ways of thinking about wireless routing.

It’s easy to see the importance of link quality in a wireless environment. Wireless links tend to have high packet-loss rate, and the transmitter needs to resend the lost packets multiple times -- wasting valuable bandwidth. Consequently, it’s often preferable in a mesh network to take a longer yet more reliable path rather than the unreliable direct route to the end point. Often the shortest path would require multiple retransmissions per packet, wasting bandwidth and increasing delays. (See Figure 1.)

Figure 1. In a single-radio mesh network, adding a hop decreases the total available bandwidth by half because every packet needs to be transmitted twice.

By continuously probing the different wireless links, every mesh node builds and updates statistics regarding every link available. These link-quality tables are then used by the routing protocol to compare every possible path and pick the optimal one at any given time.

Interference and Other Bothers
Large industrial areas are often characterized by a high density of RF devices, and the problems related to exogenous interferences deriving from other transmitters are rather frequent.

The types of interferences that may occur are due mainly to:

• Other transmitters operating on frequencies close to or coinciding with those used (e.g., Wi-Fi networks, Hiperlan data networks, and analog radio links for various purposes including video-security).
• Different devices whose operation creates interferences in the bands affected by the transmission (e.g., radars or microwave ovens).

Conversely, low-frequency (UHF, VHF) radio equipment or cellular towers are not sources of interference for most 2.4 GHz and 5 GHz radio equipment. Only extreme physical proximity of the antennas could result in reduced transmission performance.

Interference is one of the most complex phenomena that must be tackled in the area of radio transmission. It must be addressed simultaneously at different levels using the least busy channels, while also introducing redundancy into the system so that it can assist with automatic adjustment in case of unexpected interferences.

During preliminary inspections and installation, it’s important to be able to evaluate any possible interferences caused by other wireless networks existing in the area. (A Wi-Fi device in listening mode or a spectrum analyzer may be used to identify them.) It’s also always advisable to ask the customer about the existence of other radio devices in the area, their carrying frequency, their bandwidth, and power. Careful planning can solve a large percentage of problems relative to interferences.

When operating on license-free bands, keep in mind that the absence of a wireless network on the day of testing doesn’t mean that one cannot be installed in the near future. Consequently, it’s important to introduce redundancy into the network and use dynamic equipment that’s able to identify new interferences and respond to minimize their effects. This approach usually requires the use of “smart” radio equipment, often of the mesh type, set to perform constant transmission channel analysis and to select in real time the best pathway within the network and/or channel most free of interference.

When Meshing Happens
Since Franklin Industries’ network is already fiber from the office building to the mill itself, Treese extended the fiber to one office and from there installed a Fluidmesh Networks wireless network to extend the network infrastructure. Treese used a combination of FM2200 Duos and FM1100s in a point-to-multipoint fashion. The new network was installed and up and running within a week.

Keeping the customer satisfied remains the ultimate goal and, together with Fluidmesh Networks, Treese Communications did precisely that. Debbie Neal of Franklin Industries shares that “Franklin is now able to communicate through its entire company with wireless networking. We weren’t able to connect our plants together electronically due to the cost of a fiber system, but with the help of Treese Communications we are now online. Our company is now able to expedite paperwork into paperless communication and is on its way to breaking down barriers.”

 About the Author
Cosimo Malesci is co-founder and Vice President of Marketing for Fluidmesh Networks. He holds both a bachelor and master degree in Ocean Engineering from the Massachusetts Institute of Technology. After working in the marine engineering field, Malesci co-founded Fluidmesh in 2005 with offices in Boston, Massachusetts, and Milan, Italy. Fluidmesh Networks provides wireless IP Backhauling systems for security, industrial, and mission-critical applications. Its range of solutions covers point-to-point, point-to-multipoint, and mesh networks. For more information, visit www.fluidmesh.com.

Treese Communications, Inc. is a full service telecommunications company committed to staying up to date with the latest technologies and providing the best possible service, before and after the sale. For more information, visit www.treesecommunications.com.

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