Complex sentence: To this extent 802.11 RSSI has (for the most part) been replaced with RCPI; a functional measurement covering the entire received frame with defined absolute levels of accuracy and resolution.
Split into simpler sentences: To this extent 802.11 RSSI has (for the most part) been replaced with Received Channel Power Indicator. RCPI is a functional measurement covering the entire received frame with defined absolute levels of accuracy and resolution.