As Internet of Things (IoT) devices utilize different protocols on crowded bands, one major issue that emerges is communication failure attributed to coexistence. Coexistence can be defined as the capability of wireless equipment to operate when other equipment using dissimilar operating protocols is present.
In the white paper, “Overcoming Interference is Critical to Success in a Wireless IoT World,” Keysight Technologies dives into the topic of coexistence. It discusses techniques for improving coexistence of devices and networks, along with steps that can be taken to implement an effective coexistence test plan.
The white paper states that concerns surrounding coexistence are driven by three key factors. First is the increased use of wireless technology for critical equipment connectivity. The second factor is the intensive use of unlicensed or shared spectrum. Finally, there’s the higher deployment rates of sensitive equipment like intravenous infusion pumps, pacemakers, and defibrillators. These factors directly impact the reliability of medical-device communications.
Three techniques are commonly used to improve coexistence of devices and networks. One technique is physical separation. By placing two networks in different locations, each network encounters a weaker signal from the other. However, physical separation is not always practical, as is the case with healthcare environments that utilize the 2.4-GHz industrial-scientific-medical (ISM) band. In this scenario, a vast amount of wireless IoT devices throughout the facility may be operating on this band.
The second technique involves frequency separation. Essentially, interference between two networks is reduced when one network operates on a different frequency than the other—whether they are located close to one another or not. However, frequency separation is not always effective in the case of the 2.4-GHz ISM band, as Bluetooth, Zigbee, and IEEE 802.11 channels all make use of this band.
The third technique is time separation, whereby transmissions are sent and received at different times to avoid collisions. Furthermore, the white paper presents four steps that should be implemented to create a good coexistence test plan.
Keysight Technologies, 1400 Fountaingrove Parkway, Santa Rosa, CA 95403-1738; (800) 829-4444.
