RSRP (Reference Signal Received Power)

LTE

Reference Signal Received Power

RSRP is the linear average of reference signal power (in Watts) measured over a specified bandwidth (in number of REs). This is the most important measurement UE has to do for cell selection, re-selection and handover. It is very similar to CPICH RSCP in WCDMA. It is applicable while UE in different RRC states i.e. RRC_IDLE intra-frequency, RRC_IDLE inter-frequency, RRC_CONNECTED intra-frequency, RRC_CONNECTED inter-frequency

3GPP definition of RSRP in  36.214 specification is as :

Reference signal received power (RSRP), is defined as  the linear average over the power contributions 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 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. R0 is the Cell Specific Reference Signal for Antenna Port 0 and R1 is the Cell Specific Reference signal for Antenna Port 1

This measures only the reference power, we can say this is the strength of the wanted signal, but it does not gives any information about signal quality. RSRP gives us the signal strength of the desired signal and UE usually measures RSRP based on the direction (RRC message) from the eNodeB and report the value. It sends a non-negative value ranging from 0 to 97 and each of these values are mapped to a specific range of real RSRP value defined in 3GPP  36.133 specifications and given in below Table.

Reported RSRP (Integer) From RSRP Value (dBm) To RSRP Value (dBm)
00  – 140 dBm
01 – 140 dBm – 139 dBm
02 – 139 dBm – 138 dBm
03 – 138 dBm – 137 dBm
04 – 137 dBm – 136 dBm
05 – 136 dBm  – 135 dBm
06 -135 dBm – 134 dBm
07 – 134 dBm – 133 dBm
08 – 133 dBm – 132 dBm
09 – 132 dBm – 131 dBm
10 – 131 dBm – 130 dBm
11 – 130 dBm – 129 dBm
12 – 129 dBm – 128 dBm
13 – 128 dBm – 127 dBm
14 – 127 dBm – 126 dBm
15 – 126 dBm – 125 dBm
16 – 125 dBm – 124 dBm
17 – 124 dBm – 123 dBm
18 – 123 dBm – 122 dBm
19 – 122 dBm – 121 dBm
20 – 121 dBm – 120 dBm
21 – 120 dBm – 119 dBm
22 – 119 dBm – 118 dBm
23 – 118 dBm – 117 dBm
23 – 117 dBm – 116 dBm
25 – 116 dBm – 115 dBm
26 – 115 dBm – 114 dBm
27 – 114 dBm – 113 dBm
28 – 113 dBm – 113 dBm
29 – 112 dBm – 111 dBm
30 – 111 dBm – 110 dBm
31 – 110 dBm – 109 dBm
32 – 109 dBm – 108 dBm
33 – 108 dBm – 107 dBm
34 – 107 dBm – 106 dBm
35 – 106 dBm – 105 dBm
36 – 105 dBm – 104 dBm
37 – 104 dBm – 103 dBm
38 – 103 dBm – 102 dBm
39 – 102 dBm – 101 dBm
40 – 101 dBm – 100 dBm
41 – 100 dBm  – 99 dBm
42  – 99 dBm  – 98 dBm
43  – 98 dBm  – 97 dBm
44  – 97 dBm  – 96 dBm
45  – 96 dBm  – 95 dBm
46  – 95 dBm  – 94 dBm
47  – 94 dBm  – 93 dBm
48  – 93 dBm  – 92 dBm
49  – 92 dBm  – 91 dBm
50  – 91 dBm  – 90 dBm
51  – 90 dBm  – 89 dBm
52  – 89 dBm  – 88 dBm
53  – 88 dBm  – 87 dBm
54  – 87 dBm  – 86 dBm
55  – 86 dBm  – 85 dBm
56  – 85 dBm  – 84 dBm
57  – 84 dBm  – 83 dBm
58  – 83 dBm  – 82 dBm
59  – 82 dBm  – 81 dBm
60  – 81 dBm  – 80 dBm
61  – 80 dBm  – 79 dBm
62  – 79 dBm  – 78 dBm
63  – 78 dBm  – 77 dBm
64  – 77 dBm  – 76 dBm
65  – 76 dBm  – 75 dBm
66  – 75 dBm  – 74 dBm
67  – 74 dBm  – 73 dBm
68  – 73 dBm – 72 dBm
69  – 72 dBm – 71 dBm
70  – 71 dBm – 70 dBm
71  – 70 dBm – 69 dBm
72  – 69 dBm  – 68 dBm
73  – 68 dBm  – 67 dBm
74  – 67 dBm  – 66 dBm
75  – 66 dBm  – 65 dBm
76  – 65 dBm  – 64 dBm
77  – 64 dBm  – 63 dBm
78 – 63 dBm – 62 dBm
79 – 62 dBm – 61 dBm
80 – 61 dBm – 60 dBm
81 – 60 dBm – 59 dBm
82 – 59 dBm – 58 dBm
83 – 58 dBm – 59 dBm
84 – 57 dBm – 59 dBm
85 – 56 dBm – 55 dBm
86 – 55 dBm – 54 dBm
87 – 54 dBm – 53 dBm
88 – 53 dBm – 52 dBm
89 – 52 dBm – 51 dBm
90 – 51 dBm – 50 dBm
91 – 50 dBm – 49 dBm
92 – 49 dBm – 48 dBm
93 – 48 dBm – 47 dBm
94 – 47 dBm – 46 dBm
95 – 46 dBm – 45 dBm
96 – 45 dBm – 44 dBm
97 – 44 dBm

 

Practical Example of RSRP:

Let’s consider a single atnenna system and say the Reference Signal Transmitted power is about 12 dBm. A UE is located somewhere in the cell experiencing a path loss of 100 dB. Then the RSRP measured by UE should be 12-100 = -88 dBm , When we compare -88dBm value in then table it is corresponding to RSRP Integer value 52 so UE can report RSRP=52 in the measurement report.

Normally, when anyone see the UE logs measurement report ,it contained the RSRP integer value, the quick way to find our absolute RSRP value in dBm is simply subtract the integer value from -140 .Let’s take an example Integer RSRP value is 45 then corresponding RSRP dBm = -140 + 45 = -95 dBm.

Submitted By
Sukhvinder  Malik