Hello everyone,
Today I will share with you the differences between RSRP, RSRQ, RSSI, and SINR.
1. RSRP (Reference Signal Recieved Power)
RSRP is a linear average of reference signal power over a specified bandwidth (number of REs). The UE measures one of the most important counters for cell selection, reselection, and handover. Similar to CPICH RSCP in WCDMA.
In 3GPP 36.214, RSRP is defined as follows:
Reference signal received power (RSRP), is defined as the linear average over the power contributions (in [W]) of the resource elements that carry cell-specific reference signals within the considered measurement frequency bandwidth. For RSRP determination the cell-specific reference signals R0 according to TS 36.211 shall be used. If the UE can reliably detect that R1 is available it may use R1 in addition to R0 to determine RSRP.
Note:
R0 indicates the cell-specific reference signal for antenna port 0. R1 is the cell-specific reference signal of antenna port 1.
The following figure shows an example of downlink radio frames:
The red part in the figure indicates the resource elements that are being sent. The RSRP is the linear average of the power in red.
2. RSRQ (Reference Signal Recieved Quality)
As defined in 3GPP 36.214, RSRQ is defined as (N x RSRP)/RSSI, where N indicates the number of RBs (resource blocks) over the measured bandwidth.
RSRQ = N*RSRP/(EUTRA carrier RSSI)
According to the definition, the RSSI includes all types of power, including co-channel serving and non-serving cells, adjacent channel interference, and thermal noise. Therefore, (N x RSRP)/RSSI represents the proportion of the pure RS (reference signal) power to all E-UTRA power received by the UE.
RSRQ is a derived value of RSRP and RSSI, providing information about interference and desired signal strength. Because this is the ratio of two different power values, the RSRQ is in dB and the value is always negative (because the RSSI value is always greater than N x RSRP).
The UE usually measures and reports the RSRP or RSRQ based on the direction of the RRC message from the network. When the UE reports this value, the actual RSRQ value is used. The UE sends non-negative values ranging from 0 to 34. Each value is mapped to a specific range of real RSRQ values.
RSRQ measurement report mapping table
For a clearer view, expand each RSRQ value in the table and the absolute power of the mapping.
RSRQ | From | To | Unit |
00 | -19.5 | dB | |
01 | -19.5 | -19.0 | dB |
02 | -19.0 | -18.5 | dB |
03 | -18.5 | -18.0 | dB |
04 | -18.0 | -17.5 | dB |
05 | -17.5 | -17.0 | dB |
06 | -17.0 | -16.5 | dB |
07 | -16.5 | -16.0 | dB |
08 | -16.0 | -15.5 | dB |
09 | -15.5 | -15.0 | dB |
10 | -15.0 | -14.5 | dB |
11 | -14.5 | -14.0 | dB |
12 | -14.0 | -13.5 | dB |
13 | -13.5 | -13.0 | dB |
14 | -13.0 | -12.5 | dB |
15 | -12.5 | -12.0 | dB |
16 | -12.0 | -11.5 | dB |
17 | -11.5 | -11.0 | dB |
18 | -11.0 | -10.5 | dB |
19 | -10.5 | -10.0 | dB |
20 | -10.0 | -9.5 | dB |
21 | -9.5 | -9.0 | dB |
22 | -9.0 | -8.5 | dB |
23 | -8.5 | -8.0 | dB |
24 | -8.0 | -7.5 | dB |
25 | -7.5 | -7.0 | dB |
26 | -7.0 | -6.5 | dB |
27 | -6.5 | -6.0 | dB |
28 | -6.0 | -5.5 | dB |
29 | -5.5 | -5.0 | dB |
30 | -5.0 | -4.5 | dB |
31 | -4.5 | -4.0 | dB |
32 | -4.0 | -3.5 | dB |
33 | -3.5 | -3.0 | dB |
34 | -3.0 | dB |
3. RSSI (Recieved Signal Strength Indicator)
The RSSI is the total power obtained by the UE on the entire frequency band, including the power of main signals, co-channel non-serving signals, adjacent-channel interference, and even thermal noise on the specified frequency band. The RSSI is the power of the non-demodulated signal, so the UE can measure power without any synchronization or demodulation.
The following figure shows an example of downlink radio frames. The red part in the figure indicates the resource elements that are being sent. Blue and sky blue indicate synchronization signals. The green part indicates the MIB (Master Information Block). The white part is the PDSCH, where users send data. The RSSI is the total power of all colors and any possible noise or interference in all these areas.
4. SINR (Signal to Interference plus Noise Ratio)
SINR can be understood as the ratio of signal power (desired signal) to undesired noise power. Undesired signals include all external noise and internal noise.
That is all I want to share with you! Thank you!
