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Optimize Industrial Wireless Networks Cheat Sheet (DRAFT) by [deleted]

This is a draft cheat sheet. It is a work in progress and is not finished yet.

1. Overcome Channel Saturation by Using 5-GHz

Overcome Channel Saturation by Using 5-GHz Channels
In standard Wi-Fi commun­ica­tion, all Wi-Fi radios configured with the same channel setting and operating in the same Wi-Fi area share the same transm­ission medium. So, you need to take into account all radio devices in that area when evaluating the utiliz­ation of a channel. For example, while checking the 2.4-GHz channel 6 for frequency satura­tion, you need to consider all access points in the area that use this channel as well as other devices that use non-802.11 commun­ica­tion, such as microw­aves, ZigBee, and Bluetooth, on the same channel. A even further challenge is that 2.4 GHz only has 3 non-ov­erl­apping channels 1,6,and 11. If the channel is saturated, switch to a channel that is less crowded. The 2.4-GHz frequency can easily be crowded, and is generally not recommend for industrial applic­ations.

On the other hand, 5-GHz frequency provides a wide range of channels and usually has more non-ov­erl­apping channels available. However, 5-GHz channels are also used by radar systems. Most countries require wireless devices to support the dynamic frequency selection (DFS) function to legally operate in the 5-GHz frequency. Therefore, in an industrial enviro­nment, deploying devices with a 5-GHz radio along with the DFS function allows you to choose the cleanest commun­ication medium and provides you with the best overall commun­ication quality.

2. Achieve Maximum Signal Reach Long-D­istance

Achieve Maximum Signal Reach in a Long-D­istance Connection through Scientific Distance Calcul­ation
A high 802.11 wireless transm­ission rate requires a strong radio signal. Insuff­icient radio signal strength results in low throughput or discon­nec­tion. There are several ways to improve the signal reach; for example, installing high-gain antennas or switching to a lower frequency, such as 900 MHz, to reduce the effects of free space path loss. Use a wireless distance calculator to estimate the commun­ication distance and the bandwidth requir­ement for the area. A wireless distance calculator can provide you with a theore­tical model of the area in question, which you can confirm by performing a physical site survey. So, plan the long distance commun­ication parameters for your network using a distance calculator and verify the results through an actual site survey to gain more control over the wireless bandwidth and capacity of your network.

3. Maximize Link Uptime Using

Maximize Link Uptime Using Wireless Redundancy Techno­logy
Even if you have a clean commun­ication enviro­nment and sufficient signal reach, there are still other factors that could cause instab­ility in a wireless network. Setup-­related issues such as Hidden Nodes can lead to connection problems even in a well-d­esigned network. In addition, if the deployment location is not under your control, unexpected wireless interf­erence from unknown sources might also affect a well-setup network. You can use wireless redundancy techno­logies such as dual RF redund­ancy, RSTP, or Moxa's Aerolink to recover from any unexpected failures, especially in the case of critical applic­ations, to ensure maximum connection uptime.
 

4. Achieve Sufficient AP Coverage

Achieve Sufficient AP Coverage for Mobile Equipment in Your Network

Wireless APs have limited coverage. To allow wireless clients to roam smoothly between APs, you need to have coverage overlap.
Use site planning software, such as Ekahau or AirMagnet, to simulate a wireless coverage heat map to visualize the AP distri­bution in your network and then plan the number and location of the APs.
Wireless coverage can also be extended by altering the antennas, but users often overlook an antenna's vertical coverage.
Most 802.11­-based antennas are passive components that do not amplify the signal strength. The only way you can extend the signal reach is by compre­ssing the radiation pattern generated by the antenna signal.

5. Enhance Mobile Operation Using MIMO

Enhance Mobile Operation Using MIMO Client Antennas

Both 2.4 GHz and 5 GHz based wireless commun­ication require a clear Line of Sight (LoS) between the AP and its client(s). You can maintain a wireless connection using signal­-pe­net­ration and obstac­le-­ref­lection techni­ques, but signal strength reduction can still affect the stability and overall throughput of your network. One way to avoid connection sheltering by obstacles is to increase the distri­bution of APs, which can be quite expensive. Extending the client radio's antenna instal­lation to achieve proper line-o­f-sight between the APs and client can also provide tangible benefits. By using the 802.11n 2x2 MIMO technology you can install two antennas, one on the front and one on the back of a mobile device, to increase the device's wireless coverage.

6. Optimize Roaming Perfor­mance for Mobile

Optimize Roaming Perfor­mance for Mobile Operat­ions

Deploy an advanced wireless roaming technology to achieve millis­eco­nd-­level roaming break time. Even though there are standards such as 802.11r that can optimize roaming perfor­mance, most wireless M2M vendors still tend to rely on their own roaming techno­logies. Advanced roaming techno­logies enable a wireless client to automa­tically search for a new AP when the current AP connection is weak.
Configuring the correct roaming threshold parameter is critical in this setup to avoid downtime. Adopting a roaming technology that allows operators to tweak roaming parameters based on different enviro­nment and applic­ation scenarios will help optimize network perfor­mance and eliminate downtime.

7. Overcome Protocol Compat­ibility Issues

Overcome Issues Related to Protocol Compat­ibi­lity

Certain charac­ter­istics of the standard 802.11 protocol prevent transp­arent commun­ication between a wired Ethernet and a wireless link. Even though most of the TCP/IP­-based automation protocols can transmit data without problems, there are cases where the 802.11 functi­onality needs to be tweaked in order to make it compatible with the indust­ria­l-a­uto­mation protocols. The 802.11 AP/Client commun­ication address protocol was designed with the assumption that wireless clients, such as smart phones, are the endpoints of the network. This is why only a limited number of addresses are reserved in a wireless packet for this purpose. When the wireless client is not the actual endpoint, but a device that is used to connect to additional Ethern­et-­based endpoints (for example, a PLC and the field devices connected to it), the standard 802.11 protocol will not be able to forward data packets correctly using just the MAC address of the endpoint device. Moxa solves this layer 2 Ethernet commun­ication limitation using Moxa MAC Clone techno­logy. The MAC Clone technology allows the MAC address for the additional endpoint devices to be transp­arent across the wireless links, enabling wireless commun­ication for layer-2 based automation protocols such as PROFINET.

8. Handheld Device Intero­per­ability

Handheld Device Intero­per­ability Ensured by the Wi-Fi Alliance Logo

Smart handheld devices such as smart phones and tablet PCs are widely used in industrial operat­ions. Many different smart device vendors, including Apple, HTC, Samsung, and Sony, sell smart devices with different operating systems (iOS, Android, and Windows, for example). One thing that all of these handheld devices have in common is that they can all commun­icate well with factory APs via the 802.11 standard. Only devices that conform to certain standards of intero­per­ability can carry the Wi-Fi logo. The Wi-Fi logo is issued by the Wi-Fi Alliance, which is a nonprofit organi­zation that promotes Wi-Fi technology and certifies Wi-Fi products. Not every IEEE 802.11­-co­mpliant device is submitted for certif­ication to the Wi-Fi Alliance because of costs associated with the certif­ication process. However, the lack of the Wi-Fi logo does not necess­arily imply a device is incomp­atible with Wi-Fi devices, but having the Wi-Fi logo provides a certain level of confidence regarding the device's level of Wi-Fi intero­per­abi­lity.