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Frequency and Bandwidth Detection

 

i) Search the center frequency

    Note 1: This algorithm would be the most complicated and is up to each chipset manufacturer for implementation

    Note 2: Depending on UE PHY protocol stack implementation, UE may measure RSSI and determine whether it goes to next step or not.

ii) Decode PSS (Primary Sync Signal)

 

iii) Decode SSS (Secondary Sync Signal)

    Note 1 : If UE combined the result of PSS, SSS, UE can figure out Cell ID. (So if you see Cell ID in UE trace log and it matches the one eNodeB is configured, it means UE successfully detected PSS, SSS

iv) with the result of step ii) and iii), UE can detect cell specific Reference Signal

 

v) Decode BCH which occupies 72 subcarriers (6 RBs) at the center frequency.

 

vi) BCH (MIB) tells the frequency information of the system (eg. System Frequency Bandwidth)

 

MasterInformationBlock ::= SEQUENCE {

    dl-Bandwidth ENUMERATED { n6, n15, n25, n50, n75, n100},

    phich-Config PHICH-Config,

    systemFrameNumber BIT STRING (SIZE (8)),

    spare BIT STRING (SIZE (10))

}