RSRP and RSRQ

Reference Signals Received Power (RSRP) and Reference Signal Received Quality (RSRQ) are key measures of signal level and quality for modern LTE networks. In cellular networks, when a mobile device moves from cell to cell and performs cell selection/reselection and handover, it has to measure the signal strength/quality of the neighbor cells. In the procedure of handover, the LTE specification provides the flexibility of using RSRP, RSRQ, or both.

RSRP – Reference Signal Received Power is an RSSI type of measurement. It is the power of the LTE Reference Signals spread over the full bandwidth and narrowband. A minimum of -20 dB SINR (of the S-Synch channel) is needed to detect RSRP/RSRQ.

RSRQ – Reference Signal Received Quality: Quality considering also RSSI and the number of used Resource Blocks (N) RSRQ = (N * RSRP) / RSSI measured over the same bandwidth. RSRQ is a C/I type of measurement and it indicates the quality of the received reference signal. The RSRQ measurement provides additional information when RSRP is not sufficient to make a reliable handover or cell reselection decision.


RSRPSignal strengthDescription
RSRP
>= -80 dBmExcellentStrong signal with maximum data speeds
-80 dBm to -90 dBmGoodStrong signal with good data speeds
-90 dBm to -100 dBmFair to poorReliable data speeds may be attained, but marginal data with drop-outs is possible. When this value gets close to -100, performance will drop drastically
<= -100 dBmNo signalDisnonnection
RSRQSignal qualityDescription
RSRQ
>= -10 dBExcellentStrong signal with maximum data speeds
-10 dB to -15 dBGoodStrong signal with good data speeds
-15 dB to -20 dBFair to poorReliable data speeds may be attained, but marginal data with drop-outs is possible. When this value gets close to -20, performance will drop drastically
<= -20 dBNo signalDisconnection


4G (LTE)

For 4G service mode, there are four relevant measurements:

  • RSSI - Received Signal Strength Indicator. RSSI is a negative value, and the closer to 0, the stronger the signal
  • RSRP - the Reference Signal Received Power is the power of the LTE Reference Signals spread over the full bandwidth and narrowband
  • RSRQ - Reference Signal Received Quality is a C/I type of measurement and it indicates the quality of the received reference signal (similar to EC/IO)
  • SINR - Signal to Interference plus Noise Ratio (A minimum of -20 dB SINR is needed to detect RSRP/RSRQ). Indicates the throughput capacity of the channel. As the name implies, SINR is the strength of the signal divided by the strength of any interference
RSRPSignal strengthDescription
RSRP
>= -80 dBmExcellentStrong signal with maximum data speeds
-80 dBm to -90 dBmGoodStrong signal with good data speeds
-90 dBm to -100 dBmFair to poorReliable data speeds may be attained, but marginal data with drop-outs is possible. When this value gets close to -100, performance will drop drastically
<= -100 dBmNo signalDisconnection
RSRQSignal qualityDescription
RSRQ
>= -10 dBExcellentStrong signal with maximum data speeds
-10 dB to -15 dBGoodStrong signal with good data speeds
-15 dB to -20 dBFair to poorReliable data speeds may be attained, but marginal data with drop-outs is possible. When this value gets close to -20, performance will drop drastically
<= -20 dBNo signalDisconnection
SINRSignal strengthDescription
SINR
>= 20 dBExcellentStrong signal with maximum data speeds
13 dB to 20 dBGoodStrong signal with good data speeds
0 dB to 13 dBFair to poorReliable data speeds may be attained, but marginal data with drop-outs is possible. When this value gets close to 0, performance will drop drastically
<= 0 dBNo signalDisconnection

RSSI for LTE is a calculated from several other signal related measurements: RSSI = wideband power = noise + serving cell power + interference power. For example, a 4G LTE modem might report an RSSI of -68 dBm, but:

RSRP = -102 dBm

RSRQ = -16 dB

SINR = -1.8 dB

In this case, the signal quality is actually very poor. This could be due to the device being some distance away from the LTE transmitter. It’s also possible that something is interfering with the signal, such as a building or other obstructions between the device and the tower.

RSSISignal strengthDescription
RSSI
> -65 dBmExcellentStrong signal with maximum data speeds
-65 dBm to -75 dBmGoodStrong signal with good data speeds
-75 dBm to -85 dBmFairFair but useful, fast and reliable data speeds may be attained, but marginal data with drop-outs is possible
-85 dBm to -95 dBmPoorPerformance will drop drastically
<= -95 dBmNo signalDisconnection