How To Interpret RSCP(3G) / RSRP(4G) and RSRQ (LTE) parameters.

Modified on Tue, 19 Oct, 2021 at 7:29 AM

Scope

This article applies only for all devices > 3G (Not 2G).

Intended Audience

Public

In This Task

- Summary of issue

- Solution

- Related Articles

- Troubleshooting

Prerequisites

dB, dBm, dBi and dBd:

https://help.venntelecom.com/a/solutions/articles/44001930982?lang=en

RSSI

https://help.venntelecom.com/a/solutions/articles/44001930999?lang=en

Summary

All devices (smartfones, 4G routers, ...) display some parameters to help optimizing 2G/3G/4G connexions.

This article explains how to interpret some of them : RSCP, RSRP and RSRQ.

The Signal Strength is a very important and essential measure for any technology (GSM, CDMA, UMTS, LTE, etc.). However, it is not the only one. This article talks about another magnitude, equally important: the RSRP/RSRP (bm) & RSRQ (dB), which impacts strenght and quality of signal.

Although this ratios are of fundamental importance to any cellular system, they are not well understood by many professionals. On the opposite side, professionals with a good understanding of this ratios are able for example, to correctly assess the RF links, and also to perform more extensive optimizations, obtaining the best possible performance of the system.

There are many different factors that influence signal strength and quality, including but not limited to:

Tower load
Proximity to the cellular tower
Signal going through a cellular repeater
Competing signals
Physical barriers (mountains, buildings, trains, etc.)
Weather

Important note: measurements like RSCP, RSRP and RSRQ do not incorporate all of the relevant factors to describe the quality of the connection.

The other values to take in account are described in other related articles:

EC/IO - Downlink carrier-to-interference ratio (signal quality) (dB) (2G, 3G & LTE)
SINR - Signal-to-Interference-plus-Noise Ratio (signal quality) (dB) (LTE only)
RSSI - Received Signal Strength Indication (signal power) (dBm) (2G, 3G and LTE)

Disclaimers

Both Signal Strength and Signal Quality must be considered for successful cellular data connection
Measured or reported values vary by modem, carrier, and network environment
There is no black/white answer to what constitutes a successful connection
Although signal strength may appear to be adequate, throughput speeds may vary due to dependencies on cellular tower loads

Note that Power parametrs are expressed in dBm, Quality parameters in dB

Solution

RSCP (3G only)

RSCP - indicates the Received Signal Code Power

RSCP term is used for 3G coverage and becomes RSRP in 4G

In the UMTS cellular communication system, Received Signal Code Power (RSCP) denotes the power measured by a receiver on a particular physical communication channel. It is used as an indication of signal strength, as a handover criterion, in downlink power control, and to calculate path loss. In CDMA systems, a physical channel corresponds to a particular spreading code, hence the name (Received signal code power).

RSCP is also called Receiver Side Call Power.

While RSCP can be defined generally for any CDMA system, it is more specifically used in UMTS. Also, while RSCP can be measured in principle on the downlink as well as on the uplink, it is only defined for the downlink and thus presumed to be measured by the UE (User Equipment) and reported to the Node.

RSRP

RSRP is the Reference Signal Received Power is the power of the LTE Reference Signals spread over the full bandwidth and narrowband.

RSRP levels for usable signal typically range from about -75 dBm close in to an LTE cell site to -120 dBm at the edge of LTE coverage.

Knowledge of absolute RSRP provides the UE with essential information about the strength of cells from which path loss can be calculated and used in the algorithms for determining the optimum power settings for operating the network. Reference signal receive power is used both in idle and connected states

RSRP term is used for coverage same as RSCP in 3G

RSRP does a better job of measuring signal power from a specific sector while potentially excluding noise and interference from other sectors.

RSRQ (LTE only)

RSRQ is the Reference Signal Received Quality is a C/I type of quality measurement and it indicates the quality of the received reference signal (similar to EC/IO in 3G)

RSRQ is a calculated value from RSRP and RSSI . As RSRQ is a ratio of two signal powers with same same unit ( i.e. dBm) it uses dB as a measurement unit. Similar to RSRP , UE reported an integer value to eNodeB and its range is from 0 to 34

Measuring RSRQ becomes particularly important near the cell edge when decisions need to be made, regardless of absolute RSRP, to perform a handover to the next cell. Reference signal receive quality is used only during connected states

Range :- -3 to -19.5 dB

RSCP, RSRP, RSRQ and other measurements

As mentionned in summary, measurements like Signal Strength (RSSI) do not incorporate all of the relevant factors to describe the quality of the connection.

All values to take in account are described in related articles:

EC/IO - Downlink carrier-to-interference ratio (signal quality) (dB) (2G, 3G & LTE)
SINR - Signal-to-Interference-plus-Noise Ratio (signal quality) (dB) (LTE only)
RSSI - Received Signal Strength Indication (signal power) (dBm) (2G, 3G and LTE)