RSRQ

RSRQ stands for Reference Signal Received Quality. It is a radio quality metric used in LTE networks to assess how good the received signal quality is, by taking into account both the signal strength and the level of interference and noise within the measurement bandwidth. RSRQ complements other metrics such as RSRP (Reference Signal Received Power) and RSSI (Received Signal Strength Indicator) to provide a more complete picture of link quality, particularly at the cell edge.

Measurement and calculation: RSRQ is defined as the ratio of the power of the reference signals to the total received power over the measurement bandwidth. In practice it is expressed in decibels as RSRQ = 10 log10((N × RSRP) / RSSI), where N is the number of resource blocks in the measurement bandwidth. RSRP and RSSI are measured powers, with RSSI including interference and noise.

Interpretation and ranges: Higher, less negative RSRQ values indicate better link quality. Typical RSRQ values range roughly from about -3 dB (best) to around -19.5 dB (poorest). RSRQ can be degraded by interference and noise even when RSRP is strong, making it a useful indicator of overall connection quality rather than just signal strength.

Usage and significance: RSRQ is used by mobile devices and network equipment for radio resource management decisions, including cell selection, handover, and admission control. It is often evaluated alongside RSRP and CQI to gauge user experience and to optimize network performance, especially in congested or interference-laden environments. While defined for LTE and LTE-Advanced, the concept of a quality metric derived from signal and interference measurements also appears in newer generations to aid in mobility and resource management.