JODY-W2 - System integration manual
UBX-18068879 - R14
Software
Page 42 of 84
C1 - Public
3.7
Configuration of Wi-Fi transmit power limits
JODY-W2 modules contain calibration data for the output power limits in OTP. This calibration data
enables the module to achieve maximum transmit power levels that still pass the required EVM and
spectral mask limits. The maximum transmit-power levels that can be used in an end-product also
depend on:
•
Regulatory domain limits
•
Restricted band of usage
•
Gain of the antenna and antenna trace design
A configuration file on the host system and the utility
mlanutl
is used to reduce the transmit power
levels as required.
☞
Transmit power limit configuration files are provided by u-blox for the certified regulatory
domains which addresses the reference designs and the approved antennas.
⚠
The correct transmit power limits must be applied to the module after startup of the host system
or change of the regulatory domain during runtime.
Wi-Fi power table
The Wi-Fi power table defines the transmit power levels for the Wi-Fi radio. The power levels are based
on regulatory compliance, IEEE 802.11 requirements, and product design constraints. The TX power
table can be adjusted to achieve the highest transmit power level for each Wi-Fi channel, bandwidth,
and modulation within the constraints defined by the certification.
The Wi-Fi power table is defined in a transmit power configuration file,
txpwrlimit_cfg_XX.conf
,
where
“
XX
”
stands for the alpha2 country code. It allows developers to fine tune specific transmit
power levels for the Wi-Fi radio, including:
•
Band (2G and 5G)
•
Channel
•
Modulation rate (CCK and OFDM)
•
Bandwidth (20, 40, and 80 MHz)
☞
Transmit power configuration files for each completed certification are included in the Yocto
meta-layer. Transmit power config files are named as per the name of the certification region, for
example
txpwrlimit_cfg_ETSI.conf
.
The configuration files are used by the recipe in the meta-
layer to derive binary files, which can be automatically loaded by the driver, for each country in the
certification region, such as, Germany (DE), France (FR), and so on.
