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Wi-Fi - Internet of Things (IoT) Lens

Wi-Fi

Wi-Fi is a widely used connectivity option for applications that require high speed local connectivity within a limited range. These include verticals such as Smart Home, Industrial IoT, Healthcare, and Retail.

Wi-Fi has several power-saving features that can help to reduce power consumption in wireless devices. Some of the most common power-saving features in Wi-Fi include:

  • Power Save Mode (PSM): This feature allows Wi-Fi devices to enter a low-power sleep mode when not in use, reducing power consumption. During PSM, the device periodically wakes up to check for incoming data, and then returns to sleep mode.  u-APSD allows devices to selectively wake up from PSM to receive only the specific data packets that are intended for them. This allows devices to remain in PSM for longer periods of time and further reduces power consumption.

  • Wake-on-Wireless-LAN (WoWLAN): This feature allows devices to wake up from sleep mode when a wireless LAN signal is detected, rather than requiring a physical button press or other intervention.

  • Dynamic Frequency Selection (DFS): This feature allows devices to avoid using certain Wi-Fi channels that may be subject to interference, thus reducing power consumption.

  • Transmit Beamforming (TxBF): This feature allows devices to optimize their transmission patterns based on the location of the receiving device, which can improve signal quality and reduce power consumption.

  • 802.11n Power Save: This feature is designed specifically for 802.11n networks and allows devices to enter a low-power sleep mode during periods of low network activity.

  • Target Wake Time (TWT) is a feature of Wi-Fi 6 that allows devices to schedule when they will communicate with the wireless network. TWT lets a device turn on its radio interface only when it needs to communicate with the network, thereby reducing power consumption and extending the battery life of IoT devices.

  • OFDMA is a key feature of Wi-Fi 6 that improves the way data is transmitted between access points and multiple IoT devices. OFDMA divides the Wi-Fi channel into smaller sub-channels, known as resource units (RUs), and assigns each RU to a specific device or group of devices. This way, an AP can communicate with multiple devices simultaneously, and each device gets a fair share of the channel's capacity.

  • BSS coloring is a feature introduced in the 802.11ax Wi-Fi standard that helps reduce interference from neighboring access points (APs) and improve coexistence between multiple APs. The basic idea behind BSS coloring is that each BSS or AP uses a unique color (6-bit code) which is carried by the signal preamble or SIG field. The color allows client devices to differentiate between the signals of neighboring APs and avoid interference.

The power consumption in idle mode can be reduced through features such as frame bursting and low power listen, while the power consumption in sleep mode can be reduced through features such as deep sleep and wake-on-Wi-Fi.