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Random Access Procedure in LTE

When the UE has obtained system information, it has to request an RRCconnection. Like it has no dedicated resources, the UE requests the connection using the Random Access Procedure using common uplink resources.  At the end of the procedure, the UE is RRC connected UE and eNodeB are able to exchange data using dedicated radio … Read more

DL & UL Physical Channel in LTE

How Physical channel of LTE works in UL & DL?A distinction has to made between:  The Physical channel The Physical signal The DL physical channels are: Physical DL Shared Channel (PDSCH) It is a shared channel used to carry user data, radio & core network, system information (BCH), paging message. Physical DL Control Channel (PDCCH) … Read more

Work of Acquisition Indicator Channel AICH in 3G

Here I write about what is main work of Acquisition Indicator Channel AICH in 3G There is 2 types main work of AICH Carrying the Acquisition Indicators (AI), SF = 256 There are 16 kinds of Signature to generate AI The Acquisition Indicator Channel (AICH) is a common downlink channel used to control the uplink … Read more

How Non Access Stratum procedures works in LTE

The procedures for the Non Access Stratum, especially power management procedures are substantially similar to UMTS. Main change is that the UMTS EPS allows concatenation certain procedures to allow faster creation of connection and media. Create MME UE context, when the UE is on and attaches to the network. Assign a unique ID called SAE … Read more

Non-contention vs Contention Access procedure in LTE

Random access procedure is performed for the following five events: • Initial access from RRC_IDLE; • RRC Connection Re-establishment procedure; • Handover; • DL data arrival during RRC_CONNECTED requiring random access procedure; • UL data arrival during RRC_CONNECTED requiring random access procedure; E.g. when UL synchronization status is “non-synchronized” or there are no PUCCH resources for … Read more