WiFi

 

 

 

 

DRS (Data Rate Selection)

Wireless Local Area Network (WLAN) Data Rate Selection (DRS), often referred to as rate adaptation or rate control, is a mechanism used in wireless networks to dynamically select the data transmission rate at the physical layer (PHY) that is optimal under current channel conditions. The effectiveness of a DRS algorithm greatly impacts the performance of a WLAN. A well-designed DRS can significantly improve the throughput, range, and overall user experience by making intelligent decisions about which data rate to use at any given time.

Following is high level overview of how it works

  • Assessment of Channel Conditions: The WLAN device monitors various parameters to assess the quality of the wireless channel. These parameters may include signal-to-noise ratio (SNR), packet error rate, or received signal strength indication (RSSI).
  • Selection of Data Rate: Based on the assessment, the DRS algorithm selects the data rate. Higher quality channels can support higher data rates, while lower quality channels may require a step down to a lower data rate to maintain a reliable connection. The goal is to maximize throughput while minimizing errors and retransmissions.
  • Adaptation: The data rate is not fixed and can change over time. As the device moves, or as the environment changes (e.g., due to interference, obstacles, or the presence of other devices), the channel conditions will vary. The DRS algorithm continuously adapts the data rate to fit the current conditions.
  • Algorithms and Protocols: Various algorithms can be implemented for rate selection, ranging from simple ones based on trial and error (trying different rates and selecting the one with the best performance) to more complex predictive and adaptive algorithms. Common protocols like IEEE 802.11b/g/n/ac/ax have their own specifications and recommendations for rate adaptation.

 

Reference :

 

[1] Data rate selection for legacy Wi-Fi networks  

[2]