LTE, LTE-Advanced and WiMAX: Towards IMT-Advanced Networks

Acquiring System Information

While IDLE, a UE needs to acquire system information prior to getting connected. This process of system information acquisition also takes place at other instances, and in both IDLE and CONNECTED states. Such instances include reselection, recovery from link failure, both intra- and inter-RAT handoffs, and when the UE receives notification of change in system information.

System information is divided into information blocks. The standard identifies a MasterInformationBlock (MIB) and several types SystemInformationBlocks (SIBs). The MIB defines the most essential physical layer information of a cell required to receive further system information. Type 1 SIB (i.e., SystemInformationBlockTYpe1) contains information relevant when evaluating if a UE is allowed to access a cell and defines the scheduling of other SIBs. Type 2 SIB contains common and shared channel information, while Type 3 SIB contains cell re-selection information, mainly related to the serving cell. Other types of SIB carry are used to relay other specific information such availability of other EUTRA frequencies, neighboring RATs (UTRA, GERAN, CDMA2000), HNBID, ETWS, CMAS and MBMS-related information.

The MIB is transferred over the BCH. SIBs other than Type 1 SIB are carried in SystemInformation (SI) messages. Type 1 SIB also carries scheduling information for other SIB types. All SIB are transmitted on DL-SCH. Note, however, that MIB and SIB follow a fixed schedule, MIB with a periodicity ...