The blogger has not authorized any person or organization to reprint any original articles of the blogger, thank you for your support for the original!
blogger link
I work for an internationally renowned terminal manufacturer and am responsible for the research and development of modem chips.
In the early days of 5G, he was responsible for the development of the terminal data service layer and the core network. Currently, he is leading the research on technical standards for 6G computing power networks.
The content of the blog mainly revolves around:
5G/6G protocol explanation
computing power network explanation (cloud computing, edge computing, end computing)
advanced C language explanation
Rust language explanation
1. Introduction to 5G system message SIB3
In 5G NR, SIB3 only contains neighbor cell information for intra-frequency cell reselection, including each cell-specific reselection parameters and blacklisted cell information .
2. Transmission details
- Wireless signaling bearer: not applicable
- RLC-SAP：TM
- Logical channel: BCCH
- Transport channel: DL-SCH
- Physical channel: PDSCH
- RNTI加所：SI-RNTI
- Transmission direction: gNB–>UE
3. SIB3 parameter introduction
The following are the parameter types provided by NR SIB3 to UE:
- Same-frequency neighbor list
- Same frequency blacklist
3.1 List of co-frequency neighbor cells
The intraFreqNeighCellList structure of SIB3 contains a series of IntraFreqNeighCellInfo parameters, and each IntraFreqNeighCellInfo contains information about adjacent cells within the same frequency. The parameter IntraFreqNeighCellInfo contains a series of parameters such as physCellId , q-OffsetCell , q-RxLevMinOffsetCell , q-RxLevMinOffsetCellSUL and q-QualMinOffsetCell .
The meaning of the parameters is introduced in detail:
- q-OffsetCell This parameter corresponds to Qoffsets s,n
in TS38.304 , which is used to configure the offset between the serving cell and the neighboring cell , determined by physCellId . The offset (Qoffset) is also used in the evaluation of the cell sorting criterion (that is, the R criterion) of the neighboring cells. The higher the value of this field, the lower the ranking of the relevant cell; R n = Q meas,n - Qoffset - Qoffset temp - q-RxLevMinOffsetCell
This parameter specifies the cell-specific RX RSRP offset in dB. Qrxlevmin (dBm) is used to indicate the minimum RSRP value required for NR cell selection and reselection. Add the cell-specific offset q-RxLevMinOffsetCell to Qrxlevmin to obtain the minimum RSRP value required by the cell; the actual value of
Q rxlevminoffsetcell = Q rxlevminoffsetcell * 2 dB - q-RxLevMinOffsetCellSUL
This parameter has the same meaning as q-RxLevMinOffsetCell . When UE supports adjacent cell SUL, use this parameter to add Qrxlevmin to get the minimum RSRP value required by the cell; - q-QualMinOffsetCell
This parameter defines the cell-specific RSRQ offset with respect to Qqualmin in dB. Qqualmin (dB) is used to indicate the minimum RSRQ value required for NR cell selection and reselection. Add the cell-specific offset q-QualMinOffsetCell to Qqualmin to obtain the minimum RSRQ value required by the cell;
3.2 Same-channel blacklist
The intraFreqBlackCellList structure of SIB3 provides a list of blacklisted intra-frequency neighbor cells. Up to 16 PCI ranges can be configured as blacklist. Each PCI range consists of a start and PCI range .
The meaning of the parameters is introduced in detail:
- PCI range
- start indicates the starting value of the PCI of the cell in the blacklist;
- range means fromstartThe number of consecutive PCIs after that;
- For example, start = 15 and range = n8, means to blacklist PCIs 15, 16, 17, 18, 19, 20, 21, 22 and 23;
Four. Summary
- Three kinds of system information in 5G, namely MSI, RMSI and OSI;
- SIB3 is the third type of system information, that is, other system information (OSI, Other System Information);
- SIB3 only provides neighbor cell information related to intra-frequency cell reselection, including cell-specific reselection parameters and blacklisted cell information;
- SIB3 can contain specific information of up to 16 co-frequency cells, and the blacklist can contain up to 16 PCI ranges;
- SIB3 scheduling information is provided by SIB1;
- SIB3 can be broadcast periodically, broadcast on demand, or sent to terminals in a dedicated manner;
- SIB3 will be mapped to BCCH logical channel, DL-SCH transmission channel and PDSCH physical channel;
