Miniport drivers use the NDIS_STATUS_WWAN_SIGNAL_STATE notification to send a signal strength notification when measured signal strength travels outside the threshold within a pre-defined interval.
Miniport drivers can also send unsolicited events with this notification.
This notification uses the NDIS_WWAN_SIGNAL_STATE structure.
By default, miniport drivers must notify the MB Service if the Rssi value changes by at least +/-5 decibels from the last reported value, or at a maximum frequency of one indication every 5 seconds. The threshold value is specified in the SignalState.RssiThreshold member of the NDIS_WWAN_SIGNAL_STATE structure; while the maximum frequency value is specified in the SignalState.RssiInterval member.
The DeviceCaps.WwanCellularClass member of the NDIS_WWAN_DEVICE_CAPS structure controls how the Rssi value will be interpreted by the MB Service. If WwanCellularClass is WwanCellularClassGSM, Rssi is reported as decibels above the device's sensitivity noise floor. If WwanCellularClass is WwanCellularClassCDMA, Rssi is reported as compensated RSSI (accounts for noise).
Applications should never poll for signal strength. Only in special situations, such as startup, an application might use a query request to obtain signal strength.
Available in Windows 7 and later versions of Windows.