1) Frequency Search (Scan the entire frequency bands)
2) Cell Search – will search for #PSS Normally a UE would find multiple cells in this process
3) a) MIB decoding (b) SIB decoding
4) Cell Selection/ Cell Reselection
5) Initial #RACH Process >
1) Frequency Search (Scan the entire frequency bands) :
For the frequency search UE first sync with DC sub-carrier. DC sub-carrier is the sub-carrier whose frequency is equal to the RF center frequency of the transmitting station. It correspond to frequency zero (direct current) if the FFT signal is not modulated.
DC sub-carrier has no information sent on it, i.e DC subs-carrier is not transmitted, but it is counted in the number of sub-carriers. It is used by the mobile device to locate the center of the OFDM freq band.
In Frequency domain, the PSS and SSS occupy the central six RBs. 6 RBs = 72 sub-carrier,
5 Resource element is used as DTX for transmission which is used above and below the synchronization signal. The synchronization sequence use 62 sub-carrier in total with 31 sub-carrier mapped on each side of DC sub-carriers.
DTX is applied to help improve the quality of the received reference signal.
When the UE powers on, it checks if it is possible to camp on the last registered PLMN (Public Land Mobile Network).
If no any stored system on the UE, UE will perform the initial cell selection:
2) Cell Search – will search for #PSS Normally a UE would find multiple cells in this process
3) a) MIB decoding (b) SIB decoding
4) Cell Selection/ Cell Reselection
5) Initial #RACH Process >
1) Frequency Search (Scan the entire frequency bands) :
For the frequency search UE first sync with DC sub-carrier. DC sub-carrier is the sub-carrier whose frequency is equal to the RF center frequency of the transmitting station. It correspond to frequency zero (direct current) if the FFT signal is not modulated.
DC sub-carrier has no information sent on it, i.e DC subs-carrier is not transmitted, but it is counted in the number of sub-carriers. It is used by the mobile device to locate the center of the OFDM freq band.
In Frequency domain, the PSS and SSS occupy the central six RBs. 6 RBs = 72 sub-carrier,
5 Resource element is used as DTX for transmission which is used above and below the synchronization signal. The synchronization sequence use 62 sub-carrier in total with 31 sub-carrier mapped on each side of DC sub-carriers.
DTX is applied to help improve the quality of the received reference signal.
When the UE powers on, it checks if it is possible to camp on the last registered PLMN (Public Land Mobile Network).
If no any stored system on the UE, UE will perform the initial cell selection:
- Scan all RF frequencies band (ex 900MHz,1800MHz,1900MHz….) and which band are using by network
- Detect the operating frequency with the strongest RSRP
2) Cell Search – will search for #PSS Normally a UE would find multiple cells in this process
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