Wi-Fi: TWT

The TWT sample demonstrates how to use TWT power save feature.

Requirements

The sample supports the following development kit:

Hardware platforms

PCA

Board name

Build target

nRF7002 DK

PCA10143

nrf7002dk_nrf5340

nrf7002dk_nrf5340_cpuapp

Overview

The sample can perform Wi-Fi® operations such as connect and disconnect in the 2.4 GHz and 5 GHz bands depending on the capabilities of an access point.

Using this sample, the development kit can connect to the specified access point in STA mode and setup TWT flow with the access point. By default once the TWT flow is setup, the sample will use the traffic generator module to send and receive TCP data packets to and from the traffic generator server running on a PC connected to the same access point (typically through Ethernet).

Traffic generator server

When the traffic generator module is used with this sample, the traffic generator server must be running on a PC connected to the same access point. The server source is available in the scripts/traffic_gen_server file. This is a python3 based server, so you must make sure that python3 is installed on your PC.

To start the server:

  1. Set the CONFIG_TRAFFIC_GEN_REMOTE_IPV4_ADDR Kconfig option to the IPv4 address of the host running the traffic generator server.

  2. Run the following command:

    python3 traffic_gen_server.py
    

    Use the -h option to display the help message for how to use the server.

Configuration

See Configuring and building an application for information about how to permanently or temporarily change the configuration.

You must configure the following Wi-Fi credentials in the prj.conf file:

  • Network name (SSID)

  • Key management

  • Password

Note

You can also use menuconfig to enable Key management option.

See Interactive Kconfig interfaces in the Zephyr documentation for instructions on how to run menuconfig.

Configuration options

The following sample-specific Kconfig options are used in this sample (located in samples/wifi/twt/Kconfig) :

CONFIG_TRAFFIC_GEN

(bool) Traffic generation module

None

CONFIG_TRAFFIC_GEN_CLIENT

(bool) Traffic gen module acts as a Client

Enable this option to send uplink traffic to traffic gen server

CONFIG_TRAFFIC_GEN_SERVER

(bool) Traffic gen module acts as a Server

Enable this option to receive downlink traffic from traffic gen client (A python client running in Cloud).

CONFIG_TRAFFIC_GEN_DURATION

(int) Traffic gen will simulate traffic for a specified duration

Specifies how long traffic gen should simulate traffic

CONFIG_TRAFFIC_GEN_REMOTE_IPV4_ADDR

(string) Traffic gen remote host IPv4 address

Specifies the traffic gen server IPv4 address

CONFIG_TRAFFIC_GEN_REMOTE_PORT_NUM

(int) Traffic gen remote host port number

Configures the traffic gen remote host port number

CONFIG_TRAFFIC_GEN_PAYLOAD_SIZE

(int) Traffic gen payload size

Configures the payload size of the traffic gen packets

CONFIG_TRAFFIC_GEN_TYPE_TCP

(bool) Traffic type

Enable this option to select the TCP traffic type

CONFIG_CONNECTION_IDLE_TIMEOUT

(int) Time to be waited for a station to connect

None

CONFIG_TWT_SAMPLE_SSID

(string) SSID

Specify the SSID to connect

CONFIG_TWT_STA_KEY_MGMT_NONE

(bool) Open Security

Enable for Open Security

CONFIG_TWT_STA_KEY_MGMT_WPA2

(bool) WPA2 Security

Enable for WPA2 Security

CONFIG_TWT_STA_KEY_MGMT_WPA2_256

(bool) WPA2 SHA 256 Security

Enable for WPA2-PSK-256 Security

CONFIG_TWT_STA_KEY_MGMT_WPA3

(bool) WPA3 Security

Enable for WPA3 Security

CONFIG_TWT_SAMPLE_PASSWORD

(string) Passphrase (WPA2) or password (WPA3)

Specify the Password to connect

CONFIG_STA_CONN_TIMEOUT_SEC

(int) Overall Connection timeout (time to be waited for a station to connect and get an IP address)

Specify the connection timeout, in seconds. This is the overall timeout (time to be waited for a station to connect and get an IP address). DHCP retries should be taken into account when setting this value. If the timeout is set to 0, the connection will not timeout.

CONFIG_TWT_TRIGGER_ENABLE

(bool) Enable trigger mode

STA expects AP to send triggers for start of every service period.

CONFIG_TWT_ANNOUNCED_MODE

(bool) Enable announced mode

STA announces its wakeup to AP for every service period start.

CONFIG_TWT_WAKE_INTERVAL

(int) TWT awake interval

The period where STA is awake and does data transfer, interval should be in us.

CONFIG_TWT_INTERVAL

(int) TWT service interval

The period for TWT that includes both wake and sleep durations, interval should be in us. Please note higher intervals can be rejected by AP or cause interoperability issues.

CONFIG_CONTINUOUS_TX

(bool) Send traffic continuously

Send traffic continuously without any restrictions, irrespective of sleep and awake periods.

CONFIG_SCHEDULED_TX

(bool) Send traffic based on TWT schedule

Send traffic based on the TWT schedule and only transmits during the awake periods.

IP addressing

The sample uses DHCP to obtain an IP address for the Wi-Fi interface. It starts with a default static IP address to handle networks without DHCP servers, or if the DHCP server is not available. Successful DHCP handshake will override the default static IP configuration.

You can change the following default static configuration in the prj.conf file:

CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.168.1.98"
CONFIG_NET_CONFIG_MY_IPV4_NETMASK="255.255.255.0"
CONFIG_NET_CONFIG_MY_IPV4_GW="192.168.1.1"

Building and running

This sample can be found under samples/wifi/twt in the nRF Connect SDK folder structure.

When built as firmware image for the _ns build target, the sample has Cortex-M Security Extensions (CMSE) enabled and separates the firmware between Non-Secure Processing Environment (NSPE) and Secure Processing Environment (SPE). Because of this, it automatically includes the Trusted Firmware-M (TF-M). To read more about CMSE, see Processing environments.

To build the sample with Visual Studio Code, follow the steps listed on the How to build an application page in the nRF Connect for VS Code extension documentation. See Configuring and building an application for other building scenarios, Programming an application for programming steps, and Testing for general information about testing and debugging in the nRF Connect SDK.

Currently, only the nRF7002 DK is supported.

To build for the nRF7002 DK, use the nrf7002dk_nrf5340_cpuapp build target. The following is an example of the CLI command:

west build -b nrf7002dk_nrf5340_cpuapp

Testing

After programming the sample to your development kit, complete the following steps to test it:

  1. Connect the kit to the computer using a USB cable. The kit is assigned a COM port (Windows) or ttyACM device (Linux), which is visible in the Device Manager.

  2. Connect to the kit with a terminal emulator (for example, nRF Connect Serial Terminal). See Testing and optimization for the required settings and steps.

    The sample shows the following output:

    [00:00:02.016,235] <inf> twt: Connection requested
    [00:00:02.316,314] <inf> twt: ==================
    [00:00:02.316,314] <inf> twt: State: SCANNING
    [00:00:02.616,424] <inf> twt: ==================
    [00:00:02.616,424] <inf> twt: State: SCANNING
    [00:00:02.916,534] <inf> twt: ==================
    [00:00:02.916,534] <inf> twt: State: SCANNING
    [00:00:03.216,613] <inf> twt: ==================
    [00:00:03.216,613] <inf> twt: State: SCANNING
    [00:00:03.516,723] <inf> twt: ==================
    [00:00:03.516,723] <inf> twt: State: SCANNING
    [00:00:03.816,802] <inf> twt: ==================
    [00:00:03.816,802] <inf> twt: State: SCANNING
    [00:00:04.116,882] <inf> twt: ==================
    [00:00:04.116,882] <inf> twt: State: SCANNING
    [00:00:04.416,961] <inf> twt: ==================
    [00:00:04.416,961] <inf> twt: State: SCANNING
    [00:00:04.717,071] <inf> twt: ==================
    [00:00:04.717,071] <inf> twt: State: SCANNING
    [00:00:05.017,150] <inf> twt: ==================
    [00:00:05.017,150] <inf> twt: State: SCANNING
    [00:00:05.317,230] <inf> twt: ==================
    [00:00:05.317,230] <inf> twt: State: SCANNING
    [00:00:05.617,309] <inf> twt: ==================
    [00:00:05.617,309] <inf> twt: State: SCANNING
    [00:00:05.917,419] <inf> twt: ==================
    [00:00:05.917,419] <inf> twt: State: SCANNING
    [00:00:06.217,529] <inf> twt: ==================
    [00:00:06.217,529] <inf> twt: State: SCANNING
    [00:00:06.517,639] <inf> twt: ==================
    [00:00:06.517,639] <inf> twt: State: SCANNING
    [00:00:06.817,749] <inf> twt: ==================
    [00:00:06.817,749] <inf> twt: State: SCANNING
    [00:00:07.117,858] <inf> twt: ==================
    [00:00:07.117,858] <inf> twt: State: SCANNING
    [00:00:07.336,730] <inf> wpa_supp: wlan0: SME: Trying to authenticate with aa:bb:cc:dd:ee:ff (SSID='<MySSID>' freq=5785 MHz)
    [00:00:07.353,027] <inf> nrf_wifi: nrf_wifi_wpa_supp_authenticate:Authentication request sent successfully
    
    [00:00:07.417,938] <inf> twt: ==================
    [00:00:07.417,938] <inf> twt: State: AUTHENTICATING
    [00:00:07.606,628] <inf> wpa_supp: wlan0: Trying to associate with aa:bb:cc:dd:ee:ff (SSID='<MySSID>' freq=5785 MHz)
    [00:00:07.609,680] <inf> nrf_wifi: nrf_wifi_wpa_supp_associate: Association request sent successfully
    
    [00:00:07.621,978] <inf> wpa_supp: wpa_drv_zep_get_ssid: SSID size: 5
    
    [00:00:07.622,070] <inf> wpa_supp: wlan0: Associated with aa:bb:cc:dd:ee:ff
    [00:00:07.622,192] <inf> wpa_supp: wlan0: CTRL-EVENT-CONNECTED - Connection to aa:bb:cc:dd:ee:ff completed [id=0 id_str=]
    [00:00:07.622,192] <inf> twt: Connected
    [00:00:07.623,779] <inf> wpa_supp: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
    [00:00:07.648,406] <inf> net_dhcpv4: Received: 192.168.119.6
    [00:00:07.648,468] <inf> net_config: IPv4 address: 192.168.119.6
    [00:00:07.648,498] <inf> net_config: Lease time: 3599 seconds
    [00:00:07.648,498] <inf> net_config: Subnet: 255.255.255.0
    [00:00:07.648,529] <inf> net_config: Router: 192.168.119.147
    [00:00:07.648,559] <inf> twt: DHCP IP address: 192.168.119.6
    [00:00:07.720,153] <inf> twt: ==================
    [00:00:07.720,153] <inf> twt: State: COMPLETED
    [00:00:07.720,153] <inf> twt: Interface Mode: STATION
    [00:00:07.720,184] <inf> twt: Link Mode: WIFI 6 (802.11ax/HE)
    [00:00:07.720,184] <inf> twt: SSID: <MySSID>
    [00:00:07.720,214] <inf> twt: BSSID: aa:bb:cc:dd:ee:ff
    [00:00:07.720,214] <inf> twt: Band: 5GHz
    [00:00:07.720,214] <inf> twt: Channel: 157
    [00:00:07.720,245] <inf> twt: Security: OPEN
    [00:00:07.720,245] <inf> twt: MFP: UNKNOWN
    [00:00:07.720,245] <inf> twt: RSSI: -57
    [00:00:07.720,245] <inf> twt: Static IP address:
    [00:01:14.217,224] <inf> twt: == TWT negotiated parameters ==
    [00:01:14.217,224] <inf> twt: TWT Dialog token: 1
    [00:01:14.217,224] <inf> twt: TWT flow ID: 1
    [00:01:14.217,254] <inf> twt: TWT negotiation type: TWT individual negotiation
    [00:01:14.217,285] <inf> twt: TWT responder: true
    [00:01:14.217,315] <inf> twt: TWT implicit: true
    [00:01:14.217,315] <inf> twt: TWT announce: true
    [00:01:14.217,346] <inf> twt: TWT trigger: true
    [00:01:14.217,376] <inf> twt: TWT wake interval: 65024 us
    [00:01:14.217,376] <inf> twt: TWT interval: 524000 us
    [00:01:14.217,376] <inf> twt: ========================
    [00:01:14.439,270] <inf> twt: TWT Setup Success
    [00:00:15.230,773] <inf> traffic_gen: Sending TCP uplink Traffic
    [00:00:45.846,374] <inf> traffic_gen: Sent TCP uplink traffic for 30 sec
    [00:00:45.501,892] <inf> traffic_gen: Server Report:
    [00:00:45.501,922] <inf> traffic_gen:    Total Bytes Received  : 904192
    [00:00:45.501,922] <inf> traffic_gen:    Total Packets Received: 1045
    [00:00:45.501,922] <inf> traffic_gen:    Elapsed Time          : 33
    [00:00:45.501,953] <inf> traffic_gen:    Throughput (Kbps)     : 214
    [00:00:45.501,953] <inf> traffic_gen:    Average Jitter (ms)   : 0
    [00:00:45.061,767] <inf> twt: TWT teardown success
    

Power management testing

You can use this sample to measure the current consumption of both the nRF5340 SoC and the nRF7002 device independently by using two separate Power Profiler Kit II (PPK2) devices. The nRF5340 SoC is connected to the first PPK2 and the nRF7002 DK is connected to the second PPK2.

See Measuring current for more information about how to set up and measure the current consumption of both the nRF5340 SoC and the nRF7002 device.

The average current consumption in an idle case can be around ~1-2 mA in the nRF5340 SoC and ~20 µA in the nRF7002 device.

See Power optimization for more information on power management testing and usage of the PPK2.

Dependencies

This sample uses the following library: