Lecture13 - EETS 8316 Wireless Networks Fall 2013 Lecture...

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EETS 8316 Wireless Networks Fall 2013 Shantanu Kangude [email protected] Lecture: Random Access in LTE
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Random Access Procedure Important for proper participation of UEs in the Radio Network Needed if UL not syched – The only access allowed for UEs in the UL when out of UL sync Needed if eNB is not scheduling a UE, and UE needs allocation, AND no Scheduling Request (SR) channel assigned to UE – The only way to transmit in the UL without eNBs permission, or some sort of assignment RACH = Ranging/Timing Advance
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RACH for 6 Events Initial access from RRC_IDLE RRC Connection Re-establishment procedure Handover DL data arrival during RRC_CONNECTED requiring random access procedure E.g. when UL synchronization status is “non-synchronized” 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 SR available For positioning purpose during RRC_CONNECTED requiring random access procedure E.g. when timing advance is needed for UE positioning
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