The laws of physics limit wireless networks. These laws set the boundaries of how much information can be transmitted. Presented below are some key challenges of a wireless communication system.
1 - Wireless Range
The constraints on wireless radio wave transmission are the physical distance, obstacles, and fundamental wavelengths. Obstacles such as metal and concrete severely attenuate radio waves. Higher frequency systems generally have better throughput performance but with less range than systems operating in the lower frequency bands.
2 - Wireless Channel Bandwidth
Wireless communications systems transmit information over finite resources within the electromagnetic (EM) spectrum. EM spectrum is a limited natural resource divided according to the laws and regulations.
3 - Information Data Rate (Bandwidth)
Bandwidth is defined in terms of bits per second and constrained by the communications channel's physics. Realizable bandwidth rarely meets the advertised data rates as channel conditions introduce error. Competition for the channel by other devices on the wireless network creates a delay in channel access.
4 - Latency
In any communication system, transmitting and receiving data takes time. A software program must provide data for transmission, format, modulate, and share it in a wireless device. The electromagnetic waves then take time to spread through space at the speed of light, ultimately arriving at the receiver. Additional time is then required to detect the signal, reconstruct the signal into valid information, and finally deliver it to the client software application. Latency is defined as the actualized duration of information transmission from one application to another within an industrial control system.
5 - Scalability
A wireless network is designed to support a certain number of devices. Scale is an essential factor of industrial wireless networks as it influences the amount of time expected for devices to utilize the finite resources of the wireless channel. Some wireless systems, such as WirelessHART employ scheduling to assure channel availability.
6 - Wireless Security
Security within any industrial wireless deployment, mainly those considered mission-critical, should always be considered in conjunction with the wireless network design and application goals. Security holistically addresses data confidentiality, integrity, and availability issues. Unlike a traditional office setting, data integrity and availability in industrial networks are more significant concerns. For most modern wireless networks, strong encryption is available and should be used inside the factory. To ensure wireless device authentication, authentication protocols should be used to verify access. Wireless networks are also vulnerable to transmission attacks, such as jamming. In mission-critical systems, wireless network isolation is recommended by frequency and distance.
7 - System Availability
The ability of a wireless network to support its intended operation is referred to as system availability. This is typically defined in terms of a percentage availability, such as 99.99%, for which it will stay operational. Attention should be placed on the robustness of devices within the network.
8 - Harsh Industrial Environments
The physical environment usually impacts wireless communications with the presence of obstructions, reflections, and scattering. Such effects lead to multipath transmissions that may not have a direct line-of-sight (LOS) element at times. Industrial environments are more electrically noisy than office and home environments and present far more wireless transmission obstructions and disturbances. Moveable metal items such as forklifts and cranes, narrow aisles between metal shelves, and liquid tanks that can alternate propagation features are examples of this harsh environment. Moreover, depending on the frequency of the produced noise, electrical noise may affect wireless transmissions. Motors and solenoids provide examples of low-frequency noise sources. Arc-generating equipment can make higher-frequency electrical noise.
For wireless transmitters, repeaters, transmitters, antennas, and hazardous area access point enclosures, contact Analynk Wireless by calling (614) 755-5091 or visiting their website at https://analynk.com.
