The Attach Type indicates the purpose of the attach and as in most of other procedure, the attach type is also determined by a kind of mutual agreement between UE and Network. It means that UE indicates the attatch type I want to get and Network finaly determines available attach type and informs it to UE as in following procedure.
Random Access process plays two main roles – establishment of uplink synchronization and establishment of a unique UE ID (C-RNTI) known to both the network and the UE .So Random Access is used not only for initial access, but also after periods of uplink inactivity when uplink sync got lost in LTE _ACTIVE states. i) UE initiate a Random Access Procedure on the (uplink) Random Access.
Security Mode Complete is the answer to Security Mode Command message, so it is simple. If UE is also capable of the Integrity, Security algorithm that NW want to use, it send ‘Security Mode Complete’, if UE is not capable of them, it send ‘Security Mode Failure’. UL-DCCH-Message ::= SEQUENCE +-message ::= CHOICE [c1], xiii) UE moves to another cell regisn) Cell Reselection> xiv) xv) xv) Receive data . xvi) Transmit data. xvii) (If UE power is percieved too weak by the network) Network send TPC command to increase UE Tx Power, UE can select a logical root sequence based on RachRootSequenceIndex. Once UE pick a specific Logical Root Sequence Index value, it can figure out the physical root sequence index (u) based on Table 5.7.2-4. Nzc indicate ‘number of data in the ZaddOff Chu Sequence’. This number is fixed to be 839 in preamble format 1,2,3 and 139 in preamble format 4.
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ShareTechnote, ShareTechnote, So at this step, UE does not need to know anything about the network. At this step, UE does not try to decode PCPICH (in WCDMA) or Sync/Reference Signal ( in LTE ) to detect Physical Cell ID. It just measure the power of each channel.) As UE measure RSSI for each channel, it create a list of each channel numbers with the measured RSSI.
If network send UL Grant, then UE can send UL data as allowed by the UL Grant. Overall procedure is as follows : i) UE send SR (Scehduling Request) on PUCCH. ii) Network send UL Grant (DCI 0) on PDCCH. iii) UE decode DCI 0 (How UE can figure out a DCI 0 information in PDCCH is allocated for it ?, In WCDMA, UE informs on its capability as a part of RRC Connection Complete message and in LTE they defined a separate message soly designed for this kind of capability information report. The procedure is as shown below. Then UE has to report all the capability information .
6/13/2017 · In this series of Log Analysis, we are explaining about the LTE attach procedure , below is the detailed summary : Step. Direction. Channel. Message. 1. UE BCH, No MAC Header, RLC TM, No PDCP.
