Difference between spCellConfigCommon and spCellConfigDedicated

Hi All,

What exactly is difference between spCellConfigCommon and spCellConfigDedicated?

NSA UE is getting both in reconfiguration from MeNB after triggering the eventB1.

Basic difference is for BWP you can see.
Under spcell config common you have initial Dl/UL BWP related IE .
Under spcell config dedicated you have dedicated BWP.
Similarly common link with parameter used by UE for initial RACH sync with SSB.
Once UE sync then dedicated parameter are in spcell config dedicated.

spCellConfigDedicated aslo have initialBWP same as in spCellConfigCommon.

Ok, then other difference between initial access parameter and dedicated parameter.

And this is also causing the concern.

If we use spCellConfigCommon then locationAndBandwidth parameter are different for UL and DL so it wud create different center freq for UL and DL but since n/w is TDD so it can’t work.

But in spCellConfigDedicated, locationAndBandwidth parameter values are same for UL and DL so DL center freq comes same and this can work for initial access.

So I want to know whether UE uses spCellconfigCommon or spCellconfigDedicated for initial access? If spCellConfig dedicated is being used then why spCellConfigCommon is there in reconfiguration after eventb1 trigger? Whats the difference b/w both and applications ?

You can see basic parameter ssb rsrp threshold under spcell config common.
It’s very important parameter for ssb sync.
It’s not part of spcell config dedicated.
Similarly other parameters for sib1 related u can find under spcell config common.

Ok yes, but for initialBWP calculations for UL and DL, which will decide access the NR cell after B1 trigger.
spCellConfigCommon or spCellConfigDedicated?
Becasue both have exactly the same parameters for initialBWP but different values?

So SpcellConfig Common is a Comon configuration that is available to all UE, its a cell Common config for Initial Access.
Ideally this information will be sent as Part of MIB/SIB1 in SA.
In the Case of EN-DC it is sent via LTE RRC Signalling in an NR Container.
Dedicated Config will have dedicated Configuration such as diffrent. CORESET/Serachspace, PUCCH allocations, PDSCH/PUSCH time domain allocation information.
Also network can configure different BWP for Common config and Different BWP for Dedicated config, so that can be checked also with Location and BW information

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Yes, I am agreeing with all this.
My question is in case of ENDC.
For intialBWP, which “locationAndBandwidth” value is used for calculating UL/DL center frequency, the one present in spCellConfigCommon or spCellConfigDedicated (DL-common)?

There is no concept of center frequency in NR
Everything is calcaulted relative to SSB frequency
And SSB can be location in anywhere in the BW as per the GSCN location.

LocationAndBandwidth is a RIV value.

Yes, if the BWP is diffrent then LocationAndBandwidth will also change.
For example if BWP0 is configured in spCellConfigCommon with 20 MHz its LocationAndBandwidth will be different where as if BWP1 is configured in spCellConfigDedicated with 100 MHz its LocationAndBandwidth will be different.

Can we say RIV indicate the first RB in particular BWP?

Oh… seems you’re stuck on trivial points.
My question is from practical scenario and all the definitions and theory available I have read. :wink:
I am asking about intialBWP’s center freq.

There is no concept fix center freq as in LTE.
But UE will calculate the center freq of BWP assigned to it.

Yes, you have to ask why you UE calculates that in LTE.
DC carrier is at Center Frequency and PSS and SS are also located at the Center Freq, so that’s a Legacy ask.
In NR they want to avoid that that’s why tech changed.
This is in Theory and it’s an Important one.

You will have to know the reconfiguration msg received after b1 trigger and all the information elements available in it.

There is one reconfigurationWithSync and in it there is “spcellconfigcommon” in this there is “locationandBandwidth” and UE uses this to calculate DL/UL center freq for initialBWP.

Also there is spCellConfigDedicated and in it there is also BWPID and DL-common and this DL-common also has locationandBandwidth, so the question arises which locationandBandwidth value UE will consider to calculate center freq for DL/UL?
Because the values in SpCellConfigCommon and DL-common are different.

But my question comes after knowing all this.
I am not questioning about theory but the procedure as how UE will calculate after the information by MeNB is shared with it.

Just to let u all know…

From ENDC point of view, initialBWP is not activated. So the value of DL and UL freq of initialBWP is not meaningful value and can be ignored.