The Channel Quality Indicator is a feedback value sent by user equipment to the cellular network, indicating how well it can hear the downlink signal. The base station uses this index to adjust the modulation scheme and coding rate for future transmissions to that specific device. A high value means a clean signal that can support maximum data rates, while a low value forces the network to use more robust, slower coding to prevent errors.
The sector is congested and the handset is reporting a CQI of 3, so it's dropping down to QPSK modulation.
Also heard as
- channel quality indicator
Related terms
Base station subsystem
The section of a cellular network that manages radio links between mobile devices and the core network.
Downlink
The transmission path from a satellite, cell tower, or network core to the end-user device.
Cell
The geographic area covered by a single base station in a mobile network.