System Information provides information to the UEs about various parameters of both the Access Stratum and Non Access Stratum.These are the parameters that are common for all the UEs in the same cell and are traditionally broadcasted in all the wireless technologies. UEs use this information for mutliple purposes, mainly system access and other idle mode procedures like cell selection,reselection etc.
In LTE, main system information consists of the following:
1.Master Information Block (MIB) : MIB gives information about the most important parameters like SFN,system bandwidth and HICH configuration. It is transmitted every 40 ms and the scheduling information is standardised.
2. System Information Block1: SIB1 is scheduled every 80 ms. SIB1 broadcasts cell access related parameters -cell identifier (plmn id,cell id), qrxlevmin,cell specific timers and the scheduling information for all other SIBs.
3.System Information Block2: SIB2 provides information about common and shared channels-rach,prach,bcch,dlsch,ulsch etc.
4.System Information Block 3 to 8 provides information required for cell reselection.
SI3 provides information on intrafrequency cell reselection except neighbour cell information.SIB4 provides info on neighbour cell informations. SIB5 is for interfrequency cell reselection,SIB6 is for UTRAN,SIB7 for GERAN and SIB8 for CDMA related cell reselection.
UE reads the system information during the initial attach process and whenever it is camped to a new cell, it reads the relevent sysinfos.If some System Information value is changed, the network pages the UE telling the UEs that system information is changed and UEs will read the system info during the next modification cycle.Modification cycle is a cell specific parameter that is signalled in the sib2.Whenever the UE receives a paging indicating sib modification, it will invalidate all the sysinfos and retrieve all the sysinfos again.
In LTE, main system information consists of the following:
1.Master Information Block (MIB) : MIB gives information about the most important parameters like SFN,system bandwidth and HICH configuration. It is transmitted every 40 ms and the scheduling information is standardised.
2. System Information Block1: SIB1 is scheduled every 80 ms. SIB1 broadcasts cell access related parameters -cell identifier (plmn id,cell id), qrxlevmin,cell specific timers and the scheduling information for all other SIBs.
3.System Information Block2: SIB2 provides information about common and shared channels-rach,prach,bcch,dlsch,ulsch etc.
4.System Information Block 3 to 8 provides information required for cell reselection.
SI3 provides information on intrafrequency cell reselection except neighbour cell information.SIB4 provides info on neighbour cell informations. SIB5 is for interfrequency cell reselection,SIB6 is for UTRAN,SIB7 for GERAN and SIB8 for CDMA related cell reselection.
UE reads the system information during the initial attach process and whenever it is camped to a new cell, it reads the relevent sysinfos.If some System Information value is changed, the network pages the UE telling the UEs that system information is changed and UEs will read the system info during the next modification cycle.Modification cycle is a cell specific parameter that is signalled in the sib2.Whenever the UE receives a paging indicating sib modification, it will invalidate all the sysinfos and retrieve all the sysinfos again.
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