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Showing posts from October, 2020

NR MIB

Case : UE Powered ON Cell Search (PSS and SSS) and PBCH decode to get MIB Decode and store the MIB -> we will focus more on MIB itself  check if cellBarred= barred,  stop here   cellBarred != barred, move to next to process further information Decode SIB1 using parameters provided by MIB and store the results As SIB1 indicate no demand SI, decode other System Information (SIBs) The MIB includes the system information transmitted on BCH(TE->UE).     -> RLC TM      -> BCCH -> BCH->PBCH      ->    the MIB is always transmitted on the BCH with a periodicity of 80 ms and repetitions made within 80 ms (TS 38.212 [17], clause 7.1) and it includes parameters that are needed to acquire SIB1 from the cell. The first transmission of the MIB is scheduled in subframes as defined in TS 38.213 [13], clause 4.1 and repetitions are scheduled according to the period of SSB ; As per Spec:38.331 MIB ::= ...

NR MSG1 Analysis and Check points

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  NR MSG1 Detailed Analysis: FR2 +mmWave+120Khz Case: rach_ConfigGeneric {   prach_ConfigurationIndex == '10'   msg1_FDM == 'one'   msg1_FrequencyStart == '0'   zeroCorrelationZoneConfig == '0'   preambleReceivedTargetPower == '-74'   preambleTransMax == 'n100'   powerRampingStep == 'dB4'   ra_ResponseWindow == 'sl80' } totalNumberOfRA_Preambles == '63' totalNumberOfRA_Preambles == '10 ssb_perRACH_OccasionAndCB_PreamblesPerSSB  one  : 'n48' ra_ContentionResolutionTimer == 'sf64' prach_RootSequenceIndex :  l139 == '0' msg1_SubcarrierSpacing == 'kHz120' restrictedSetConfig == 'unrestrictedSet' As per Spec , Preamble Format A1, Starting symbol =0  and 38.211 v15.3.0- Table 6.3.3.2-4 : Random access configurations for FR2 and unpaired spectrum 38.211 -  Table 6.3.3.1-2: Preamble formats  for    and    where   ...

PRACH Tx power Check points

  In 5G when UE has to send RACH to initiate communication with gNodeB it has to evaluate the path loss in order to know with how much power UE has to transmit PRACH to compensate this path loss.  How the UE calculate this?  It is based on one measurement SSB-RSRP ( that is the SSB RSRP measured by UE in that specific location, in that specific moment in time) and  Based on one information element ss-PBCH-BlockPower that is the SSB power transmitted by gNodeB ( located either in SIB1 in 5G SA or in RRC Connection reconfiguration in 5G NSA). So, for example, if SSB_RSRP=-91 dBm and ss-PBCH-BlockPower=21dBm then  UE will calculate pathloss PL=ss-PBCH-BlockPower-SSB_RSRP=21-(-91)= 112 dB.  Now knowing this value of PL=112dB and knowing preambleReceivedTargetPower=-104dBm ( also located either in SIB1 in 5G SA or in RRC Connection reconfiguration in 5G NSA)  UE will calculate what will be the P_PRACH power UE needs to transmit PRACH like this P_PRACH - PL ...