What is the minimum RSSI needed for 3G or LTE ?

What is the minimum RSSI needed for 3G or LTE ?
December 14, 2015 • 8 Likes • 0 Comments

RSSI is a Radio-Frequency (RF) term and stands for Received Signal Strength Indicator. It is a measure of the power level that a RF device, such as WiFi or 3G client, is receiving from the radio infrastructure at a given location and time.

For LTE:

In short the RSRP/RSRQ are the relevant ones for LTE performance. If SINR (same as SNR or S/R) is available it is easiest to use for alignment. Use table below as indication. If SNR is, say 13 dB but RSRP is below -80 or RSRQ is below -10 it indicates a problem but if they are in same range as table then easiest to use SNR only.

The RSSI is not that relevant for LTE, but could be calculated as below:

RSSI – Represents the entire received power including the wanted power from the serving cell as well as all cochannel power and other sources of noise and it is related to the above parameters through the following formula:

RSRQ=N*(RSRP/RSSI)

Where N is the number of Resource Blocks of the E-UTRA carrier RSSI measurement bandwidth.

Generally up to 20 times speed increases are possible between bottom and top when combining increased signal with de-correlated MIMO antennas. Signal strength only increase with single antenna or two antennas without much de-correlation can give about 10 times speed improvement.

FOR GSM/3G/HSPA:

RSSI is measured in dBm. The dBm scale is roughly between -50 and -120dBm, with -50 being perfect signal and -120 being when you fall off the network. RSSI measures both the usable signal and the noise in a single figure.

-50 to -75 dBm – High Signal
-76 to -90 dBm – Medium Signal
-91 to -100 dBm – Low Signal
-101db to -120 dBm – Poor Signal

>25 dB – Great signal
18-25 dB – Very good
11-18 dB -  Medium
5-10 dB - Low
4 dB – Very poor

Generally data rates can vary by about 10x from Low/Poor to High/Very good on HSPA

You also need to remember that an outdoor antenna typically increases received signal by 15 dB to 25 dB. This increases RSSI, SNR and other parameters by the same amount. I have a detailed paper with credible references which confirms these numbers. We also have on record about 5000 actual measurements where we have replaced indoor antennas with outdoor antennas for operators which show even larger signal increases – very likely due to antenna gain.

For LTE the improvement in de-correlation between the MIMO antennas also contributes to speed increases.

Please contact info@poynting.co.za or +2712 657 0050 for more information on Poynting or the products we offer.

www.poynting.tech

Reference
https://www.linkedin.com/pulse/what-minimum-rssi-needed-3g-lte-andre-fourie

Informations
STANDARDS OF #3G:
International Telecommunications Unit (ITU) IMT-2000 consists of five radio interfaces:
1.W-CDMA
2.CDMA2000
3.CDMA2001
4.TD-CDMA / TD-SCDMA
5.UWC-136

#3G is a generic term covering a range of future wireless network technologies, including WCDMA, CDMA2000, UMTS and EDGE. 3G combines high-speed mobile access with Internet Protocol (IP) based services.

Reference: http://seminarprojects.com/Thread-3g-mobile-communication-technology-full-report#ixzz4Avbtcf52

#Iraq

#هندسة_الاتصالات