Energy pulse technology eliminates wireless network signal interference

Serious wireless network Interference

As one of the three major protagonists of short-distance wireless technology, Bluetooth, Zigbee, And WiFi have been gaining traction since their launch. Thanks to their advantages in technology, cost, energy consumption, simplicity, and other aspects, they have developed rapidly.

At present, WiFi has become the lifeline of wireless data transmission in home and office environments. Almost all smartphones, tablets, and PCs use WiFi for high-speed information interaction. Bluetooth is slow but consumes less energy. It is usually used to connect peripheral devices, such as wireless headsets, printers, and scanners. Zigbee is a protocol that provides low data volume, low energy consumption, and long battery life. It is widely used in household automation, healthcare, and other industry devices.

However, Bluetooth, Zigbee, and WiFi are both in the GHz band, so the interference between the three is also very serious. In addition, the Wi-Fi Access Points of different standard systems are too many, which may cause mutual interference. These two factors seriously affect the network speed and reliability of the wireless network.

Energy pulse technology eliminates wireless network signal interference

But the good news is coming! Kang Shin, University of Michigan science professor, and his assistant launched the GapSense System in last July to send special energy pulses for traffic control signals through WiFi, Bluetooth, and Zigbee, avoid signal transmission conflicts between wireless devices and overcome signal interference problems in the same band. Shin indicates that no matter which wireless protocol is used between the transmitter and the transmitter, the transmission signal interference problem can be solved.

To effectively avoid conflicts, three wireless protocols, namely Bluetooth, Zigbee, and WiFi, adopt a mechanism to transmit only one signal at a time. However, unfortunately, these three mechanisms are different and they cannot be interconnected.

Generally, these three technologies follow the CSMA principle. CSMA is a protocol that allows multiple devices to send signals over the same channel. The devices in CSMA can monitor whether other devices are busy and send signals only when the lines are idle. In an extreme case, when the number of collisions reaches 16, the system automatically gives up sending. Therefore, CSMA cannot fundamentally avoid interference, and the interference between the three wireless technologies also often occurs.

In particular, the mutual interference between Wi-Fi and Zigbee is more serious. We know that the underlying Zigbee standard divides the 2.4 GHz ISM band into 16 channels, and the bandwidth of each channel is 2 MHz. However, WiFi divides the frequency band into 11 direct expansion channels, and the system can select any of them for communication. The channel bandwidth is 22 MHz, so 11 channels overlap, A maximum of three overlapping channels can be created. Obviously, assuming that the Wi-Fi system works on any channel, the probability that Zigbee overlaps with its channel frequency is 1/4. When Zigbee and WiFi use the same frequency band for communication at the same time, internal colored noise interference is generated, resulting in transmission group conflict.

In addition, the interference between WiFi and WiFi is also very serious. With the development of the WiFi standard, in order to improve the capacity and transmission rate, the new WiFi standard adopts a wider channel than the previous generation. For example, when the 802.11b device needs to send data, it notifies the Wi-Fi network to allocate a bandwidth of 10 MHz sub-channel. At this time, the 802.11n device with 40 MHz sub-channel bandwidth also has data packet transmission, but at this time it does not know that the 8.2.11b device has a sending requirement, at this time, for the 80.2.11n device, the 80.211b device becomes a "hidden terminal", so the packets of the two devices are extremely prone to conflict.

To coordinate the spectrum between these different devices, Shin and his research team have designed a new communication mechanism-the GapSense technology. GapSense uses a series of energy pulses separated from the blank to avoid signal conflicts by monitoring the gap between the pulse energy and the long and short pulses in the 2.4GHz band.

New technologies are expected to effectively reduce energy consumption

It is reported that GapSense uses the virtual carrier sensing method to determine when clear and clean signal transmission can be performed without considering which communication protocol is used, therefore, interference between different types of devices can be significantly improved. For example, in a wi-fi, Bluetooth, and ZigBee Wireless office network environment, the collision probability between ZigBee and WiFi is 45%. After using the GapSense technology, the collision rate is reduced by 8%. At the same time, the problem of "hidden terminals" has also been reduced from 40% to almost zero.

In addition, the GapSense technology isolates WiFi transmitters with faster time and pulse speeds and low-speed units that send wake-up signals so that they can catch up with the expected information packets without waiting and listening signals, therefore, the energy consumption is reduced by 44%.

The application of the GapSense technology involves firmware and driver updates for network devices and Wi-Fi access points. Most vendors do not yet do this. Therefore, this new technology may have to wait for the time to popularize. At present, the University of Michigan is seeking business partners to help bring the gap sense technology to the market.