Scheduling request at random access
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The document discusses different methods for scheduling uplink transmissions in LTE including Buffer Status Report (BSR), Scheduling Request (SR), and Random Access procedures. It distinguishes between contention-based and non-contention based random access, with non-contention used for positioning, handover, and downlink data when in connected state, and contention-based used for establishing connections, reestablishing connections, and initiating uplink/downlink data transfers. It details the messages involved in contention-based random access including Message 3.
![Message 3 on DCCH
- Transmission of uplink or downlink data
Message 3 :
UL Information Transfer message
[SERVICE REQUEST]
MME
UPLINK NAS TRANSPORT
[SERVICE REQUEST]](https://image.slidesharecdn.com/schedulingrequestatrandomaccess-130717213250-phpapp01/85/Scheduling-request-at-random-access-7-320.jpg)
Scheduling request at random access
- 1. Scheduling Request at Random access Brian, Kang brian.kang@juniglobal.com
- 2. Seeking Resources - UE 1. Buffer Status Report(BSR) ○ already PUSCH resources allocated for uplink transmisstion 2. Scheduling Request(SR) ○ no ongoing uplink data trasfer on PUSCH ○ uplink synchronizion for SR 3. Random access procedure ○ no ongoing uplink data transfer ○ no PUCCH resource for sending an SR
- 3. Random Access Contention-based random access Noncontention-based random access
- 4. Noncontention-based Random Access 1. Initiation of the downlink data transfer 2. Handover 3. UE positioning *** only for UEs in the RRC_CONNECTED state ***
- 5. Contention-based Random Access 1. RRC Connection establishment 2. RRC connection reestablishment 3. Initiation of the downlink data transfer 4. Initiation of the uplink data transfer 5. Handover
- 6. Contention-based Random access - Message 3 Message3 on CCCH ● RRC Connection setup ● RRC Connection reestablishment Message3 on DCCH ● Handover ● Transmission of uplink data ● Transmission of downlink data
- 7. Message 3 on DCCH - Transmission of uplink or downlink data Message 3 : UL Information Transfer message [SERVICE REQUEST] MME UPLINK NAS TRANSPORT [SERVICE REQUEST]
- 8. Reference 1. LTE Air Interface Protocols