RSRP RSRQ RSSI in LTE

By -

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.
A minimum of -20 dB SINR (of the S-Synch channel) is needed to detect RSRP/RSRQ




Reference Signal Received Quality(RSRQ): It is defined as quality of the received reference signal.
Quality considering also RSSI and the number of used Resource Blocks (N) RSRQ = (N * RSRP) / RSSI measured over the same bandwidth
The RSRQ measurement provides additional information when RSRP is not sufficient to make a reliable handover or cell reselection decision. 


RSRQ distribution in a live network



Received Signal Strength Indicator (RSSI):It is the linear average of the total received power (in [W]) observed only in OFDM symbols containing reference symbols for antenna port 0, in the measurement bandwidth, over N number of resource blocks by the UE from all sources, including co-channel serving and non-serving cells, adjacent channel interference, thermal noise etc.

 RSSI (wideband

power) = noise + serving cell power + interference power.

where Pi
Total = total received wideband power in the ith symbol

When 100% down link PRB is active without noise and interference, RSSI=12*N*RSRP, where
N is number of RBs across the RSSI, which is measured and depends on the bandwidth


under full load (100% PRB utilization) and high SNR

RSRP (dBm)= RSSI (dBm)- 10 * log (12 * N)

RSRQ = (N * RSRP) / RSSI

Example: RSRP=−82dB, RSSI=−54dB, N=100 => RSRQ=10lg100 + (−82)−(−54)=−8dB

 RSRP versus RSSI for full loaded cell (10MHz).

Comments

Post a Comment

Popular posts from this blog

Pa Pb in LTE and its impact on User Throughput

By -
Image
Downlink signals are  made up of many different components. For example, Reference Signal, PDCCH, PDSCH etc. The RS power and the SCH powers are key RF optimization parameters that influences the cell coverage. It is set according to the cell size. The higher the setting, the larger the cell coverage  on the downlink, but leaves smaller power headroom available for other downlink signals  and channels. The relation between RS power and power on PDSCH symbols (includes type A and type B symbols), has to be defined and reported to the UE, in order for the UE to demodulate 16QAM and 64QAM.1 PDSCH type A symbols has only PDSCH RE’s, PDSCH type B symbols has mixed RS and PDSCH REs. Parameter PA sets the power of PDSCH type A RE relative to cell‐specific RS, PB sets the power relation between PDSCH type B RE, and PDSCH type A RE (ρB/ρA in 3GPP). The ratio of PDSCH EPRE to cell‐specific RS EPRE among PDSCH REs for each OFDM  symbol is denoted by either ρA or ρB according to the OFD
Read more

LTE Layer management Strategy and basic working [LMS] Unlock

By -
Image
LMS Insight Layer Management Parameter Optimization is important aspect & it is triggered when all possible optimization techniques for ensuring best experience to customers is exhausted in the current layer For Example in a typical 3 Layered cellular network, we have LTE layer (with a mix of TDD(2.5GHz) and FDD(1.8GHz)), followed by WDCMA Layer (WCDMA2100) & then the GSM layer (1800 MHz Before actually working on Layer Management Parameter Optimization, we need to ensure Traffic Balancing within the layers is proper & as per recommendations to give desired customer experience Pre-requisite Actions Ensure below checks before moving to optimize the Layer Management Thresholds for a cell. Traffic balancing within layers should be optimal -  if network has 2 layers of LTE i.e. both TDD-20 MHz & FDD-5 MHz, Traffic distribution for collocated cells with TDD/FDD should be 75:25 (TDD: FDD) or better. This is applicable to networks with 2 carriers of WCDMA as well where the tra
Read more