Why RSRP range is different in 4G and 5G?

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Hi All.

Why RSRP range is different in 4G and 5G?

L1 ss-rsrp range is -140 dBm to -44 dBm, while L3 ss-rsrp range is between -156 dBm and -31 dBm.

Both these values signaled / represented using 7 bits.

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Hi @Ankur .

What I assume is ,for LTE, the range is wider (-140dBm to -44dBm) because it is designed to work in a variety of environments with different signal conditions. This range covers weaker signals (-140dBm) that might be present in areas with poor coverage and stronger signals (-44dBm) found in areas with excellent signal quality.

In 5G NR SA, the range (-31dBm to 156dBm) reflects the expanded capabilities of 5G technology. The lower end (-31dBm) represents very strong signals, which can be achieved with advanced antenna systems and close proximity to base stations. The higher end (156dBm) represents weaker signals that can be received at the edge of coverage areas or in challenging environments.

5G NSA RSRP Range: Similar to LTE RSRP Range (-140dBm to -44dBm)

In Non-Standalone mode, 5G networks rely on an existing LTE infrastructure for certain functionalities. Therefore, the RSRP range for 5G NSA is similar to the LTE RSRP range. It encompasses weaker signals (-140dBm) in areas with poor coverage and stronger signals (-44dBm) in areas with excellent signal quality, similar to LTE.

So based upon these statements, LTE and 5G have different signal strength ranges due to factors like frequency bands used, technological advancements, network design, and different design goals. LTE has a wider range to accommodate various signal conditions, while 5G’s range reflects its wider frequency range and advanced capabilities. These ranges are set by 3GPP based upon network configurations, deployment scenarios, and specific equipment used , for optimal performance and compatibility.

Hope this answers your question.

Well experts in this forum are free to correct me or can add info if I missed some.

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Check this, it will help you to know the answer:

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Hi, focusing in this part of your question:
“L1 ss-rsrp range is -140 dBm to -44 dBm, while L3 ss-rsrp range is between -156 dBm and -31 dBm.”

I will give my ideas quoting some excerpts of the book “5G New Radio IN BULLETS”, by Chris Johnson:

  1. Reduction from -140dBms to -156dBms was introduced initially in LTE to cater for the coverage performance of enhanced Machine Type Communications (cMTC). The 3GPP specifications for LTE originally defined a minimum RSRP of-140dBm but that value was decreased to -156dBm within the release13 version of the specifications.
  2. Then, for 5G, the minimum Layer 3 value of -156dBm has been aligned with the minimum Layer 3 value specified for LTE.
  3. So, L3 Minimum Measured/Reported RSRP value is -156dBm, but L1 Minimum Reported value is -140dBm, which is viewed as sufficient for the purposes of Layer I procedures. Here, I’m assuming that L1 Minimum Measured is the same that L3, -156dBm.
  4. Given that there are 7 bits when signalling RSRP, it can be defined 128 entries: RSRP_0< -156, RSRP_1< -155, RSRP_2< -154… RSRP_125<-31. RSRP_126<-31, RSRP_127:Infinity. New maximum RSRP value could be -31dBm.
  5. So, L3 Maximum Measured/Reported RSRP value is -31dBm, but L1 Maximum Reported is -44dBm, which is viewed as sufficient for the purposes of Layer I procedures. Here, I’m assuming that L1 Maximum Measured is the same that L3, --44dBm.
  6. -31dBm used by 5G is viewed as sufficient when compared to the upper limit of -44 dBm used by LTE, taking into account that it considers 10 dB margin for UE receiver beamforming relative to LTE.
  7. For example, if the UE MEASURES a Layer 1 RSRP of -150dBm then it is REPORTED AS < -140 dBm, but the same case is MEASURED AND REPORTED AS L3 -150dBm.

Please feel free to correct, add info or comment.

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Which QC is for L3 SS-RSRP measurement?
L1 SS-RSRP & CSI-RSRP seem to be B8D8.