System Frame Number: this is the clock of eNodeB.PCFICH location is fixed and known, so by knowing PHICH location, UE can read the critical PDCCH region structure to get control level information for further decoding of broadcast information. PHICH information: The size and duration of PHICH channel is given here, which is essential to differentiate between PCFICH and PDCCH channel (as all control channels share same region).System Bandwidth: Determines how many resource blocks are functional for this cell, necessary for decoding any other physical channels.Upon decoding MIB, UE knows the following:

This way, UE is ensured that it can create complete MIB even from the copies, and knows when a new MIB is transmitted (and the 40ms boundary).

Since MIB is very crucial, it is transmitted every 40ms, with the copies being transmitted every 10ms.

This is where MIB is transmitted on the physical broadcast channel. Having acquired the measurement units (slot and frame level synchronization), UE latches on the same center frequency and this time reads first 4 OFDM symbols of second slot of first sub frame. This is acquired by something called Master Information Block (MIB). STEP 2: DOWNLINK SYNCHRONIZATIONįirst key information that UE needs to know is the system bandwidth. The strongest RSRP emitting frequency is selected, and UE moves onto the next step. This is a power measurement level of signal, analogous to which frequency is the strongest. Suppose UE finds signals in all the band frequencies, which frequency does UE tune in? Frequency latching is decided on basis of something called RSRP or Reference Signal Received Power. So when my phone is switched on for the first time, it scans all these supported frequencies to see whether network is available. This is analogous to a simple radio scan operation, which scans for all channels to check where the music is playing! For example, my Moto X play phone supports 800/900/1800/2100/2600 MHz frequency. Your phone scans all the available radio frequencies in the given LTE band, also known as E-UTRA Absolute Radio Frequency Channel Number or (EARFCN). When you switch on your brand new LTE enabled phone for the very first time, the first step (and this is true for all generations) is scanning.

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