Hi NR Experts.
How many BWP defined from gNB to UE?
Like we have initial DL/UL BWP…
What does default DL and UL BWP indicate?
I think max 4 BWP can be configured for one UE.
But only 1 active at a time.
BWP is where the UE will receive PDSCH in RB and symbols.
Yes it can be 4 max, but I’ve seen mentioned default DL and UL BWP.
In logs I see
- Initial DL/ UL BWP
- Dedicated BWP
- Active BWP
- Initial BWP
- Small dedicated BWP
- Large dedicated BWP
- Power saving BWP
These are BWP types that can be configured to UE.
However at the moment only 1 will be active.
Initial BWP UE get in SIB1 to perform procedure like RACH, Paging etc.
Once UE will get connected it’s get BWP also called First Active BWP… Which is also a Default BWP.
Remember UE can be configured up to 4 as per capability, but only one BWP will be active at a time!
In idle mode UE uses Initial BWP… you will observe bwp-0 in UE modem log.
Please check this → 5G NR Bandwidth Part (BWP) - #8 by Ali_Khalaf
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Yes, same I have written 
In Dedicated Mode I see in logs, we have BWP Common and BWP Dedicated options
BWP Common:
- 1 pdcch config common
- 2 pdsch config common
BWP Dedicated:
- 1 pdcch config
- 2 pdsch config
- 3 radio link monitoring
Initial DL BWP seen as part of sib1 in case of NR SA but for endc it’s part of spcellconcig.
Yes, that’s right.
This Active BWP what you mentioned Default BWP is seen, but it doesn’t have any structure or IE content.
You might have seen bwp1 common in RRC setup message…
That comes under first active downlink BWP or uplink BWP.
Please check structure carefully.
There is no specific BWP as first active.
Based on UE capability and gNB configuration, small or large BWP can be configured as first active BWP.
For NSA logs as part of rrc reconfiguration:
- Spcell config
- 1 initial DL/UL BWP
- Spcell config dedicated
- BWP id 1 having
- DL/UL bwp common
- DL/UL bwp dedicated
For SA logs:
- Sib1 having serving cell config common
- 1 initial DL/UL BWP under DL/UL config common having pdcch, pdsch config -common etc.
- RRC setup having spcell config dedicated having
- Initial DL/UL BWP having pdcch-config ,pdsch-config etc
For search space need to configure monitoring symbols within slot what these 14 bits means?
Any idea?
It indicate which symbol in slot have pdcch monitoring occassion.
Usually 1st and 2nd bit is 1.
That’s right!
But whatever BWP you will receive in RRC setup will be under first active downlink/uplink BWP.
All depends on your gNB configuration like how much RBs you want to allocate first time in “locationandbandwidth”.
As explained above: it’s number of symbol / position UE need to monitor at PDCCH Monitoring occasion under that search space.
We have IE duration under control resource set to add mod list indicating number of symbol used for pdcch.
How is it different from this monitoring symbols in slot IE?
Can we set all 14 bits to 1?
For NR we have 3 symbols for PDCCH i.e. static can’t change according to load like in 4G.
IE duration will indicate the number of symbols used for PDCCH and according to that you will get the number of bits 1 in monitoring symbols.
So all 14 bits can’t be 1 as we have limitations of maximum duration = 3 in NR case also.
For more understanding on slot and symbols level you can refer this:
To search for PDCCH in a slot both CORESET and searchSpace information are needed.
The IE duration in CORESET gives the number of pdcch symbols to be monitored and the start symbol index from where n symbols (n = duration) are to be monitored is provided by the IE monitoringSymbolsWithinSlot.