Guidelines (Wi-Fi)

Welcome to the Online Power Profiler (OPP) for the nRF70 Series of Wi-Fi 6 companion ICs. Use this tool to estimate the current consumption of the nRF70 Series devices under certain operating scenarios of interest. The OPP tool covers both 2.4 GHz and 5 GHz Wi-Fi operation and various Wi-Fi operation modes. The tool can be configured using a wide set of Wi-Fi networking and nRF70 Series radio parameters.

The OPP for Wi-Fi currently supports nRF70 Series Wi-Fi operation in the following modes: 

  1. Station (client) mode, that is, when the nRF70 Series device is connected to (associated with) an Access Point (AP) network. The current focus is on estimating the power consumption of the Wi-Fi devices when they operate under the various Wi-Fi power saving modes. 
  2. SSID scan mode, that is,  when the nRF70 Series device is not associated with any AP, but only performs scanning for neighboring APs, e.g. for Wi-Fi assisted locationing. The focus is on estimating the nRF70 Series energy consumption for the scan-only operation, with respect to the various configurations available through the scan API.
  3. Offloaded beaconing mode, that is, when the nRF70 Series device is not associated with any AP, but only performs periodic beaconing, configured using the nRF Connect SDK TX Offload API

The OPP simulations for Station mode are based on current consumption measurements conducted on an nRF7002 DK connected to a Wi-Fi 6 AP network. The OPP tool is to be used for evaluation purposes only and will not give the exact power consumption numbers in every scenario. 

Please check out this blog showing how to perform your own current consumption measurements for the nRF70 Series ICs, using the nRF7002 DK and the Power Profiler Kit from Nordic Semiconductor and compare those measurements with the current consumption estimations from the OPP tool.

Contents

Supported devices  

The OPP for Wi-Fi currently supports the nRF7002 and nRF7001 devices for the Station and TX Offload mode profiling and all three nRF70 variants, nRF7002, nRF7001, and nRF7000, for the Scan mode.

Station mode

The OPP for Wi-Fi currently simulates the current consumption of an nRF70 Series device when it operates as Station under Power Saving Mode (PSM). The nRF70 Series ICs support multiple power saving modes, enabling the devices to minimize power consumption while keeping the connection to the access point. Refer to the nRF70 Series PSM guide to understand more about the different Wi-Fi power saving modes.

When connected to an AP, there are several network operation parameters that the nRF70 device is not able to control, as they are set by the AP itself. These parameters include (but not limited to) the DTIM period or the Beacon packet payload and transmission rate. These parameters may have a significant impact on the nRF70 Series current consumption, and in order to get an idea of what to expect when you connect to an AP network of interest, you can use the OPP to match the network parameters, and then see the expected current consumption.

Supported parameters 

Chip settings 

  • Chip: the nRF70 Series variant used in the simulation. Choose between nRF7002 and nRF7001. 

Wi-Fi settings 

  • Frequency: the frequency band the nRF70 Series device operates on. Choose between 2.4 GHz and 5 GHz. 
  • PSM mode: the power saving mode the nRF70 Series device operates on. Choose between DTIM (legacy PSM) and TWT (additional power save mode supported in Wi-Fi 6 networks). 

DTIM (legacy power save mode) parameters 

  • DTIM period (interval): the parameter that indicates how often (in multiples of beacon interval periods) the AP sends out multicast or broadcast messages to connected devices. Stations operating in legacy PSM wake up at every DTIM beacon to listen for pending buffered traffic. The DTIM period is controlled by the AP and is typically configurable in AP settings.  
  • Listen interval: a parameter that indicates how frequently (in multiples of beacon interval periods) a Station device will wake up to check for pending buffered traffic. The listen interval may be set by the Station device; however, it will be rounded down to the nearest multiple of DTIM value. A larger listen interval allows devices to save more power but may result in frame reception losses. Select 0 to disable listen interval setting. 
  • Beacon payload: a parameter that indicates the length of the beacon frame payload in bytes. The beacon payload is set by the access point. Typical beacon payload lengths depend on the generation of Wi-Fi supported and on the set of Wi-Fi features enabled in an AP network. Typical beacon frame payload lengths: 450 (802.11ax), 350 (802.11ac), 250 (802.11n), 100 (legacy). 
  • DSSS enable: a parameter that indicates that the AP will support DSSS (legacy) mode. Typically, DSSS compatibility may be enabled or disabled in the AP configuration settings. When disabled it allows APs to transmit beacon frames at a higher data rate and hence shorter frame-on-air time. 

TWT 

  • TWT wake interval: a parameter indicating the time interval between successive WT wake periods.  
  • TWT Wake Duration: a parameter indicating the amount of time that the Station device under TWT needs to be active to complete the frame exchanges during the TWT wake period.  
  • TWT TX Payload: a parameter indicating the amount of data traffic (in payload bytes) the device under TWT is expected to send to the access point (i.e. uplink) during a TWT period. Select 0 to simulate a scenario where a device has no pending uplink data under a TWT period (in which case a null uplink packet will be transmitted in order to maintain the connection). 

Scan mode 

The OPP for Wi-Fi scan currently simulates the energy consumption of an nRF70 Series device when it operates in scan-only mode. The nRF70 Series ICs support multiple scan configurations and profiles, enabling the devices to optimize their energy consumption based on the application environment and requirements. Refer to the nRF70 Series Scan Optimization guide to understand more about the different Wi-Fi scan profiles and configurations.

In scan (i.e. non-connected) mode, certain network parameters, such as the payload of the probe request frames, or the number of received probe responses during active scanning are not controlled by the user scan API, but they may impact the device current consumption in scan mode. These parameters are exposed in the OPP tool settings so users can configure them to match the expected conditions.

Supported parameters  

Chip settings  

  • Chip: the nRF70 Series variant used in the simulation. Choose between nRF7002, nRF7001, and nRF7000.  

Scan settings

  • Force passive: An option to force passive scanning on all selected bands and channel maps. When turned on, the option does not allow configuring active scan operation. Force passive will turn active scanning to passive on the channels active scanning was previously selected. 
  • Active Scan dwell time per channel [ms]: Active scan duration parameter per channel in milliseconds. Applies to all channels where active scanning is selected.
  • Passive Scan dwell time per channel [ms]: Passive scan duration parameter per channel in milliseconds. Applies to all channels where passive scanning is selected. 

Channel map settings

  • Number of channels to scan: The number of channels in each selected band to be included in the scan session for active and passive scanning. The total number of channels selected in each frequency band may not exceed the total number of available (and supported) channels in this band.

Note: the tool does not take into consideration region-based regulatory rules that prevent Wi-Fi active scanning in certain channels.

Active scan parameters

  • Active probe request payload: The payload (in bytes) of the active scan probe requests transmitted by the nRF70 series devices. 
  • Number of probe responses: The number of probe responses expected to be received on each channel nRF70 device performs active scanning. This is not controlled by the nRF70 device, but it impacts the current consumption since the device needs to respond with acknowledgement frames.

The tool generates a graphical representation and an accurate estimation of the average current consumption and duration of a complete scan session including radio ramp up and power off phases (over all selected bands and channels).

TX Offload mode

The OPP for Wi-Fi Offload TX mode currently simulates the energy consumption of an nRF70 Series device when it operates in offloaded periodic TX beaconing (raw TX) mode. That is, when the nRF70 Series device can be configured to transmit frames at regular intervals, utilizing very low power, and without interrupting the host MCU. The most popular offloaded raw TX use-case is periodic Wi-Fi beaconing.

The nRF70 Series ICs support multiple raw TX configurations, allowing the devices to optimize their energy consumption based on the application environment and requirements. Refer to the Offloaded raw transmit mode to understand more about the different configurations options for offloaded raw TX mode.

Supported parameters  

Chip settings  

  • Chip: the nRF70 Series variant used in the simulation. Choose between nRF7002 and nRF7001. (nRF7000 does not support TX offload mode)  

Wi-Fi beaconing settings

  • Frequency: An option to select the frequency band of the Wi-Fi beaconing mode between 2.4 GHz and 5 GHz. Note that the exact channel (within the selected band) where beaconing will be performed does not impact the power consumption of the nRF70 Series device.
  • TX Output power [dBm]: An option to configure the output power of the transmitted beacons, in dBm.
  • TX Rate [Mbps]: An option to configure the beacon on-air transmission rate in Mbps. Higher rates typically result in lower average current consumption, as on-air transmission time is lower.
  • TX Beacon interval [ms]: An option to configure the period of beacon transmissions, in milliseconds.
  • Beacon payload [bytes]: An option to set the beacon frame payload length. Larger beacon payload will result in larger average current consumption.

Disclaimer 

This tool is based on a model of measured values and is not showing the actual power measurements. The results are therefore an estimate of the expected current consumption values. 

The measurements which the model is based upon are conducted on a nRF7002 DK board while communicating with a Wi-Fi 6 AP. This is a controlled test environment representing in many cases ideal conditions which may not be reproducible in a real network environment. It does not consider poor signal conditions or channel contention, which would result in packet errors and retransmissions. 

 

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