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Reliable Video Transmission over High Bandwidth Industrial Wireless Networks

In the past ten years, huge strides have been made in improving wireless technologies; so much so that many industrial networks are being converted from wired to wireless. The reason is straightforward—with wireless communication no cabling is required, making wireless networks much cheaper and easier to implement compared to wired networks. However, because of the bandwidth constraints that come with using wireless, video-over-wireless was not really feasible until about five years ago, at which time 802.11n and 3G HSPA technologies were mature enough for use with industrial applications.

Many industrial networks are now being designed to support video data transmissions, with most of the data generated by IP surveillance systems. With security more important now than ever before, the demand for higher resolution IP cameras is also growing. However, IP surveillance systems create greater bandwidth demands on your industrial network infrastructure. To support seamless video streaming over a wireless network, operators must understand how much bandwidth each camera will need, and then calculate the total network bandwidth required for simultaneous data transmissions.

The following two tables provide valuable information for engineers who are preparing to install wireless equipment. Table 1 provides an estimate of the amount of network bandwidth required to achieve real-time video transmission based on the quality, resolution, and FPS. Table 2 gives the data rate and maximum achievable bandwidth for different network protocols.

Table 1: Video Bandwidth Requirement

Video Bandwidth Parameters Required Bandwidth Estimate*
FPS: 20
1 to 2 Mbps
3 to 5 Mbps
7 to 9 Mbps

*Generated using Moxa’s online Bandwidth Calulator.

Table 2: Wireless Bandwidth Map

Wireless Technology Data Rate Max. Available Bandwidth
Wireless LAN (802.11/WiFi) Technology*
802.11b 11 Mbps ≈ 5 Mbps (distance dependent)
802.11a/g 54 Mbps ≈ 25 Mbps (distance dependent)
802.11n (2x2 MIMO) 300 Mbps ≈ 150 Mbps (distance dependent)
802.11ac 600 Mbps ≈ 300 Mbps (limited transmission distance)
Wireless WAN (Cellular) Technology
2G (GPRS/EDGE) 86, 236 kbps ≈ 100 kbps (ISP dependent)
3G (HSPA) 14.4 Mbps 1 to 3 Mbps (ISP dependent)
Pre 4G (LTE) 100 Mbps 20 Mbps (limited coverage)

*Generated using Moxa’s online WLAN Range Calculator.

Knowing how to calculate both video data and wireless network bandwidth is an essential first step in planning a video-over-wireless network, and although choosing wireless devices is driven primarily by the amount of network bandwidth you’ll need, it is also important to ensure that the devices will work smoothly under different application scenarios.

Video-over-Wireless Application Scenarios

Although 802.11ac and LTE are the latest wireless technologies, in terms of interoperability and coverage, they still aren’t mature enough for use with industrial applications. Currently, the key technologies available for enabling video-over-wireless are 802.11n and 3G. Based on our experience helping end-users implement real-world applications, we can categorize industrial video-over-wireless communication into one of the following three scenarios.

Scenario 1: Remote IP Surveillance

Intersection monitoring, factory surveillance, and harbor surveillance are good examples of applications that will inevitably require removing existing nodes or adding new nodes. The main problem faced by our customers is that if they’re stuck using a wired network connection, there’s a good chance they will need to lay new cables when adding new nodes. If using wireless communication is an option, they can easily add the new nodes without installing additional data line cabling. Two key factors that must be considered when doing this are wireless coverage and real-time communication.

Depending on what degree of wireless coverage is required, Moxa provides a complete range of wireless solutions supporting different transmission distances. For a local wireless network, which usually means within a 300 meter transmission radius, 802.11 radios are a good choice due to their higher gain omnidirectional antennas. For longer communication distances, cellular technology can provide a more stable solution.

Once you decide to go wireless, it is important to adopt a network design that provides sufficient bandwidth to ensure that your connection will support real-time video transmissions. In this regard, Moxa provides two useful tools: a Video Bandwidth Calulator that allows users to determine how much bandwidth is required for each camera, and a WLAN Range Calculator that provides an initial estimate of data rates, ranges, and the antenna gain settings that AWK series products can support.

When operating mission-critical and safety-critical systems in hard-to-wire environments, packet loss during wireless transmissions can compromise safety and reliability. Moxa has products that overcome this problem. Moxa’s dual-radio wireless solutions feature the proprietary Concurrent Dual-Radio Technology, which achieves zero packet loss for industrial applications. For cellular connections, Moxa’s GuaranLink feature ensures reliable and consistent cellular connectivity, which translates into zero data loss and on-demand cellular communications.

Scenario 2: IP Surveillance for Vehicles

The development of wireless technology has made it possible to connect vehicles of various shapes and sizes to stationary networks. Applications of this type include bus surveillance, metro surveillance, and truck driver monitoring, all of which are now feasible by using wireless communication. The main hurdle that must be overcome for all of these applications is how to ensure smooth video streaming while the vehicle’s wireless device is handed off from one access point to another. Moxa is an expert at wireless roaming technology, and due in part to Moxa’s proprietary roaming algorithms, Moxa’s wireless devices are now widely used to support wireless communications for a variety of mission-critical vehicle applications.

Scenario 3: Passenger WiFi

The previous two application scenarios implement centralized communication. That is, video streams from one or more remote sites (which could be on the move) are fed to a control center. However, with the now widespread use of handheld devices, industrial wireless is no longer just serving industrial wireless client radios. Setting up a passenger WiFi network on a passenger train is one example. In addition to the high bandwidth required to serve many handheld devices, setting up a reliable wireless backbone network is an important part of onboard WiFi applications. Inter-carriage communication needs a better solution to make setup and maintenance easier for operators, particularly since train consists frequently change during daily service. Moxa’s Auto Carriage Connection technology is specifically designed to solve this problem by automating the previously manual process of creating new wireless bridges that provide broadband communications throughout the entire train, while still maintaining robust network security.

Choose the Right Solution for Your Scenario

As we can see from the above scenarios, different types of video applications have different concerns. One thing we can be sure of is that regardless of the scenario, providing seamless video transmissions through an industrial video-over-wireless network requires a rugged hardware design. Moxa’s industrial wireless products have been designed for any kind of industrial application. Features like a wide -40 to 75°C operating temperate range, vibration-proof M12 and QMA connectors, a high level of EMS protection, and a variety of industrial certifications, ensure that your wireless transmissions are reliable.

Moxa has all of the knowledge, experience, and technology needed to deploy a video-over-wireless network. To obtain greater insight into the benefits Moxa can offer customers who would like to implement seamless video transmission over high bandwidth wireless networks, click here to download Moxa’s Video-over-Wireless Application Guidebook.

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