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Asset Health, IoT, Fleet Management, Productivity Monitoring, High Precision GPS, Safety, Security, Asset Tracking, Communication, Connectivity. There’s a lot happening on your wireless network. It seems the request for more data and more access is nearly non-stop.
How do you scale your network to handle this constant increase in scope?
Exactly, what is the problem?.
There are actually several things that can be done to increase performance of your existing network. The first challenge is in understanding where the true bottleneck is. That bottleneck can then be addressed cost effectively, winning the necessary improvement, and often without the need for a complete forklift upgrade.
In most in-pit networks that 3D-P has analyzed, the bottleneck isn’t the available throughput of the wireless solution, although that certainly has a major impact on the problem. No, the challenge is actually congestion.
This is particularly true in outdoor networks where there is little to no attenuation of RF signals, many machines working in close proximity to each other, and multiple applications that are designed for real-time, or near real-time data acquisition. Sounds familiar?
Reduce congestion. Improve scalability of your wireless network.
The good news is there are ways to limit this RF congestion, freeing up the air to carry more of this critical data. Here are three tricks you might want to remember.
Trick #1: Reduce the RF coverage of each radio.
I can hear the questions now: ‘What? The problem I’m having is loss of connectivity in certain areas. I need more coverage, not less.’
Here’s the rub. In wireless networks that are based on the 802.11 protocol (which covers a huge % of the networks used in mining today), whenever one device can hear another device transmitting, say one truck can hear the shovel next to him transmitting to the access point, that device must back off, wait a period of time before checking the air again to see if it is free, and only when it is free trying to transmit. That back-off time is admittedly very small.
But when the network is busy, i.e. lots of applications sending real-time (read as nearly constant) data, the device that wants to transmit something new can very quickly end up waiting so long the message times out. To the user it looks like dropped coverage, but it’s really just a busy network.
Reducing the RF coverage of each device by using lower gain, or directional antenna to control coverage areas, can help reduce the number of other devices each truck has to contend with for access to the air.
Now this reduction of RF coverage may mean adding additional access points to allow complete coverage of your site. In that case, we need to be certain to remember trick #1 to ensure we don’t actually add to the problem. So, we will utilize smaller gain and directional antennas to control the overlap between coverage zones.
Trick #2: Employ a network scaling, congestion controlling solution – Channelization.
If we can deploy this new AP on a channel that won’t overlap with other AP’s around it, but that the trucks can still find, we can drastically improve network performance. This isn’t often easy, but it can typically be handled, particularly when used in conjunction with trick #1, i.e. using appropriate antennas to help make sure adjacent access point zones that do share the same channel overlap minimally. Terrain can also be used as an aid to trick #1, i.e. blocking the signal from one AP to another by deploying the AP next to a hill, dump, high wall, etc.
Trick #3: Use appropriate distribution to remove traffic from the mobile network as soon as possible.
There are many backhaul/distribution solutions available. It may be as simple as using a multi-radio infrastructure device that is capable of sending upstream traffic on a separate radio or channel from that used by the mobile equipment. Or you might opt for a distribution solution that uses an entirely different protocol as well as a different channel from what your mobile fleet is using. For example TDMA distribution radios don’t rely on the “listen until the network is available” solution, but rather assign each connected client radio a time-slot to transmit. That way each radio is certain to be able to get its data out, without the waiting game.
In the end, there are options for scaling and improving the performance of your existing network. Choosing the right technologies and deployment methodologies certainly make it easier.