Adaptivity Test

Supported Chips

Ameba SoC	RTL8721Dx	RTL8726E	RTL8720E	RTL8730E
FreeRTOS	Y	Y	Y	Y
Linux	Y	N	N	Y

Adaptivity Test Introduction

Standard

Adaptivity is an automatic channel access protocol that inhibits a device from transmitting on a channel when ongoing transmissions are detected. Devices with a maximum declared RF output power level greater than 10 dBm effective isotropic radiated power (e.i.r.p.) are required to implement this Adaptivity protocol.

Since December 31, 2017, ETSI has required Adaptivity certification. The applicable standards are ETSI EN 300 328 V2.2.2 for 2.4 GHz bands and ETSI EN 301 893 V2.1.1 for 5 GHz bands.

The Adaptivity test procedures are specified by ETSI as follows:

1. Establish a connection between the DUT (Device Under Test) and the companion device and start data transmission.

2. Add the interference signal, and ensure that out-of-band blocking signals are also added for 2G compliance.

3. Check whether the DUT has stopped transmitting data.

4. The DUT is restricted to transmitting only short control signals, such as acknowledgment (ACK) frames, to the companion device.

5. Check the test result.

   • For 2G compliance, check whether the Tx duty cycle is below 10% within any 50ms interval. If yes, pass; otherwise, fail.

   • For 5G compliance, check whether the Tx duty cycle is below 5% within any 50ms interval. If yes, pass; otherwise, fail.

6. Repeat the steps above for each channel, bandwidth, and mode.

Interference Power

The energy detection formula specified by ETSI is as follows:

2G: TL = -70dBm/MHz + 10*log10(100mW/Pout)
5G: TL = -75dBm/MHz

Note

Pout is the maximum TX power of test object. The interference signal must exceed BW of the test object and have a 100% duty cycle.

Realtek conducts testing under the most stringent conditions in the LAB.

2G: TL = -70dBm/MHz
5G: TL = -75dBm/MHz

The table below illustrates the interference power with different frequencies and bandwidths. When the interference power exceeds the threshold, the MAC layer will be instructed to pause data transmission.

Item	2G		5G
	20MHZ	40MHZ	20MHZ	40MHZ	80MHZ	160MHZ
Interference Power (dBm)	-57	-54	-62	-59	-56	-53

The following section details the software configuration and debug SOP essential for successfully passing the Adaptivity test.

Software Configuration

EDCCA Mode

Ameba supports four EDCCA mode types:

Mode	description
RTW_EDCCA_NORM	Dynamically adjusts the EDCCA threshold based on real-time RSSI measurements and is configured as the default mode.
RTW_EDCCA_ADAPT	Utilizes a fixed threshold to meet the requirements of ETSI Adaptivity test.
RTW_EDCCA_CS	Implements Carrier Sense to comply with Japan’s interference avoidance regulations.
RTW_EDCCA_DISABLE	Allows MAC transmission without EDCCA signal verification.

The EDCCA mode types are specified in the file wifi_api_types.h located under component/wifi/api/wifi_api_types.h.

/*The enumeration lists the edcca mode types*/
enum rtw_edcca_mode {
   RTW_EDCCA_NORM = 0, /* normal*/
   RTW_EDCCA_ADAPT = 1, /* Adaptivity, ETSI*/
   RTW_EDCCA_CS = 2, /*carrier sense, Japan*/
   RTW_EDCCA_DISABLE = 9, /*disable*/
}

FreeRTOSLinux

• Static Adjustment

  RTL8721DxRTL8720ERTL8726ERTL8713ERTL8730E

  File path: component/soc/usrcfg/amebadplus/ameba_wificfg.c

  Function: wifi_set_user_config()

  • For the ETSI Adaptivity test, configure the EDCCA mode to RTW_EDCCA_ADAPT

    wifi_user_config.rtw_edcca_mode = RTW_EDCCA_ADAPT;
    

  • For Carrier Sense, configure the EDCCA mode to RTW_EDCCA_CS

    wifi_user_config.rtw_edcca_mode = RTW_EDCCA_CS;
    

  The configuration will be applied during the Wi-Fi initialization process.

• Dynamic Adjustment

  Not support.

EDCCA Threshold

FreeRTOSLinux

Once connected to the AP, retrieve the current EDCCA threshold using the following command:

AT+WLDBG=get_edcca_th

In most scenarios, the default settings suffice to pass the Adaptivity test. If modification is required, adjust the EDCCA threshold using the following command:

AT+WLDBG=fix_edcca_th <value>

Note

The value’s unit is dBm and the scope is [-60, -80], and the minimum step is 1.

For example:

AT+WLDBG=get_edcca_th
[WLDBG]: _AT_WLAN_IWPRIV_
[WLAN-A] [iwpriv_command] cmd name: get_edcca_th
[WLAN-A] edcca thre=-60 dbm

AT+WLDBG=fix_edcca_th -62
[WLDBG]: _AT_WLAN_IWPRIV_
[WLAN-A] [iwpriv_command] cmd name: fix_edcca_th

Debug SOP

Checklist	Points
Test SDK	The SDK is in normal mode, not in manufacturing (MP) mode. The EDCCA mode is set to RTW_EDCCA_ADAPT.
Test Environment	Testing should be conducted in a shielding room. Connect all antennas to controlled interference sources. When packet loss occurs, verify that the packet type transmitted by the DUT is not an ACK (Acknowledgment) packet. Maintain the device’s RSSI at -50dBm or higher. Adaptivity test measures the Tx of the DUT, not the Rx. Interference energy is measured in dBm, not dBm/MHz.
Optimize the EDCCA threshold	Use ATWZ command to modify EDCCA threshold.

Country Code Setting

TBD

Transmit Power Setting

TBD

DFS

TBD