LTE Rel8 Radio Protocols Seung June Yi seungjune

LTE Rel-8 Radio Protocols Seung. June Yi (seungjune. yi@lge. com) Sung. Jun Park (sungjun. park@lge. com) Click Sung. Hoon Jung (sunghoon. jung@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2010. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

Agenda § § § Copyright LTE Overview Idle mode procedure RRC protocol MAC protocol RLC protocol PDCP protocol All Rights Reserved 2 / 122 LG Electronics RAN 2 Team

LTE Overview (Rel-8) Seung. June Yi (seungjune. yi@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2009. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

LTE targets ¢ Significantly increased peak data rate l e. g. 100 Mbps (downlink) and 50 Mbps (uplink) l Increased "cell edge bit rate" l Significantly improved spectrum efficiency ¢ Scalable bandwidth l Peak data rates scaled linearly to spectrum allocation ¢ Mobility Support l Optimized for mobile speeds 0 to 15 km/h l Support of high speed UE between 15 km/h and 120 km/h l Maintain mobility at speeds between 120 km/h and 350 km/h (Up to 500 km/h) l Support of voice and real-time services over entire speed range ¢ Improved latency l C-Plane : Idle-to-Connected < 100 ms l U-Plane : UE-to-e. NB < 5 ms (1 Frame = 10 ms, 1 Subframe = 1 ms) ¢ ¢ Support of paired/unpaired spectrum operation Reduced CAPEX and OPEX Inter-working with existing 3 G systems /non-3 GPP systems Further enhanced MBMS Copyright All Rights Reserved 4 / 122 LG Electronics RAN 2 Team

LTE Releases Timeline SI start 05 Copyright All Rights Reserved WI start 06 5 / 122 07 R 8 08 09 R 10 R 9 10 11 12 LG Electronics RAN 2 Team

E-UTRAN Architecture MME S-GW EPC Interfaces S 1 -MME e. NB • S 1: e. NB to MME/SGW • C-plane: S 1 -MME • U-plane: S 1 -U • X 2: e. NB to e. NB • Uu: e. NB to UE S 1 -U X 2 Uu E-UTRAN UE UE UE Copyright All Rights Reserved 6 / 122 LG Electronics RAN 2 Team

Network node functionalities EPC E-UTRAN e. NB MME Inter Cell RRM RB Control NAS Security Connection Mobility Cont. Idle State Mobility Handling Radio Admission Control EPS Bearer Control e. NB Measurement Configuration & Provision Dynamic Resource Allocation (Scheduler) S-GW RRC PDCP RLC S 1 Mobility Anchoring P-GW UE IP address Handling Packet Filtering MAC Internet PHY Copyright All Rights Reserved 7 / 122 LG Electronics RAN 2 Team

Protocol Stack User Plane protocol stack UE e. NB Control Plane protocol stack UE e. NB MME NAS Copyright NAS RRC PDCP RLC RLC MAC MAC PHY PHY All Rights Reserved 8 / 122 LG Electronics RAN 2 Team

LTE Radio Protocol New Features RRC PDCP Copyright Simplified RRC operation § Reduced number of SRBs (0, 1, 2) § Reduced number of RRC messages and procedures § Reduced number of SIBs (up to 11) § Reduced number of RRC states (Idle/Connected) Header Compression using only ROHC Security (Ciphering and Integrity Protection) Explicit PDCP Sequence Number Reordering / Duplicate detection / In-order delivery Selective forwarding / retransmission at handover RLC Flexible Size PDU HARQ reordering Delayed status reporting Re-segmentation of RLC PDU in re-transmission MAC Shared-only Transport channel (DL-SCH/UL-SCH) Enhanced Random Access procedure Multi-level DRX Starvation avoidance for low priority RB Timing alignment MAC Control PDU TTI bundling All Rights Reserved 9 / 122 LG Electronics RAN 2 Team

LTE Idle Mode (Rel-8) Sung. Hoon Jung (sunghoon. jung@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2009. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

Idle mode functionalities PLMN Selection He. NB support Cell selection Camping on a cell Cell reselection Paging Location Registratio n Copyright All Rights Reserved 11 / 122 LG Electronics RAN 2 Team

Camping on IDLE mode Reception of System Information Reception of paging Initiate Connection Request Reception of ETWS Copyright All Rights Reserved Oh I see I am cell A This is my information SIB Ok Let me go to Connected mode Paging Someone wants to talk to you Connection Request I want to talk to someone Oh No…. 12 / 122 Connection Request ETWS Oh ok Let me see what I can do Tsunami is coming!!!!!! LG Electronics RAN 2 Team

Service Types Public Use on Suitable Cell Norma l Servic e Emergency call on Acceptable Cell Limited Service Operator use on Reserved Cell Copyright All Rights Reserved 13 / 122 LG Electronics RAN 2 Team

After power on PLMN List OK! I see you System Information Paging ETWS notification PLMN A PLMN B POWER ON PLMN A PLMN B PLMN Selection Ph 1 Ph 2 R 96 R 97 R 98 Copyright All Rights Reserved I am here! Location Registration Cell selection R 4 R 5 R 6 14 / 122 R 7 R 10 LG Electronics RAN 2 Team

Cell Selection 3 rd 2 nd 1 st Camping on Cell B Evaluation Scanning Result Suitable Cell A Cell B Cell C Acceptable Cell Radio Quality Cell A Cell B Reserved Cell B Cell C Cell A Copyright All Rights Reserved 15 / 122 LG Electronics RAN 2 Team

Cell Reselection Principles Highest priority principl e P 1. UE should camp on frequency of highest priority Cell Reselectio n P 2. UE camps on best ranked cell on a frequency Copyright All Rights Reserved Best Cell principl e 16 / 122 LG Electronics RAN 2 Team

Cell Reselection Ranking Priority Frequency 1 Priority : 3 Frequency 2 Priority : 5 Cell A Cell C Cell B Frequency 3 Priority : 2 OK! I see you Cell E Cell D Cell F I am here! Cell A Cell B Cell C - UE was camping on Cell A - Quality: Cell A > Cell C > Cell D R 5 Cell. R 4 reselection Copyright All Rights Reserved 17 / 122 R 6 R 7 Location R 10 Registration LG Electronics RAN 2 Team

Paging DRX cycle Subframe B I will send paging message at subframe B Paging Record List P-RNTI OK I will wake up at subframe #B PDCCH Copyright All Rights Reserved 18 / 122 Paging Record UE Identity ETWS Indication SI Mod. Info PDSCH LG Electronics RAN 2 Team

He. NB Support in Idle ¢ He. NB = Customer-Premises e. NB Anyone will be welcome any UE Only CSG member is allowed Non-member any UE Normal Cell of e. NB Copyright All Rights Reserved member CSG Cell of He. NB 19 / 122 LG Electronics RAN 2 Team

H(e)NB Access Mode Open mode (R 8) Hybrid mode (R 9) Closed mode (R 8) CSG member Access Preferential Access CSG non-member Access Non-member Normal Hybrid Cell Normal Cell Copyright All Rights Reserved 20 / 122 Non- member Closed CSG Cell LG Electronics RAN 2 Team

Idle UE behaviors for H(e)NB Support • Membership check by reading CSG ID of CSG cell and comparing it with UE CSG white-list • Intra-frequency cell reselection is always allowed regardless of any CSG cell presence Copyright All Rights Reserved • Highest frequency priority assumption for highest ranked member CSG cell CSG membershi p identificatio n Frequency priority handling in favor of CSG cell Handling of nonmember CSG in cell reselection CSG cell detection 21 / 122 • Manual search at initial visit • Autonomous search at revisit LG Electronics RAN 2 Team

LTE RRC Protocol (Rel-8) Sung. Hoon Jung (sunghoon. jung@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2009. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

Fundamental of Radio Resource Control NAS message delivery RRC Security Activation Mobility Control Measurement Control … RLC configuration per RB RRC messages RB configuration PDCP RLC • Antenna Configuration • Configuration of physical channels … Copyright All Rights Reserved • Random access parameters • UL SCH configuration … MAC PHY 23 / 122 LG Electronics RAN 2 Team

Signaling Radio Bearers Default Configuration (CCCH) Connection (re)establishment (DCCH) Connection Reconfiguration (DCCH) SRB 0 CCCH RRC messages SRB 1 DCCH NAS messages Copyright All Rights Reserved SRB 2 24 / 122 LG Electronics RAN 2 Team

NAS Service Request Journey of RRC procedures RRC Connection Establishment Proc. SRB 1 established, to RRC_Connected Security Activation Proc. RRC Reconfiguration Proc. Ciphering & Integrity activated Cell selection Radio Link Failure Detection Select a suitable EUTRA cell All RBs except SRB 0 suspended System Information Acquisition Proc. Obtain system information SRB 2 & DRB(s) established, UE specific configurations RRC Connection Reestablishment Proc. Handover Proc. Access to another cell RRC Reconfiguration Proc. Possibly other cell than serving cell, UE specific SRBs & DRBs resumed configurations Measurement Serving and neighboring cells Measurement Report measurement result Connection Release Proc. RRC connection released! SRBs, DRBs released, to RRC_Idle UE NAS Copyright All Rights Reserved 25 / 122 LG Electronics RAN 2 Team

Functions of RRC System information delivery RRC connection control • Paging • Access Class Barring • Establishment/modification/release of RRC connection • Initial security activation • Intra-LTE mobility • Qo. S control • Recovery from radio link failure; Inter-RAT mobility Measurement Generic protocol error handling Support of self-configuration and self-optimisation Copyright All Rights Reserved 26 / 122 LG Electronics RAN 2 Team

System Information Broadcast Oh my god! I’m reading emergency warning info. I got essential physical layer configurations to access this cell MIB, SIB 1, SI 2, SI 3, … I got a cell reselection info. for idle mode I’m checking if this cell can be accessible I obtain common configurations to apply for this cell Copyright All Rights Reserved 27 / 122 LG Electronics RAN 2 Team

System Information Structure SIB 2 MIB SIB 1 • Essential physical layer information • Cell access related information • Scheduling information of other SIBs • Access class barring information • Cell specific radio resource configuration info. • MBSFN allocation info. • UL frequency / UL bandwidth SIB 3 • Common cell re-selection parameters SIB 4/5 Fixed scheduling • Intra/Inter frequency reselection parameters SIB 6/7/8 • Inter-RAT reselection parameters SIB 9 • HNB name SIB 10/11/12 Dynamic scheduling • ETWS information, CMAS information SIB 13 • MBMS control information Copyright All Rights Reserved 28 / 122 LG Electronics RAN 2 Team

Scheduling of System Information A SIB is included in one SI message Mapping SIBs onto SIs is flexible Information block MIB SIB 1 SIB j SIB n SIB k SIB m … Flexible mapping message MIB Copyright All Rights Reserved SI 2 SIB 1 Period x 29 / 122 SI 3 Period y … LG Electronics RAN 2 Team

System Information Validity Value Tag in SIB 1 Value tag=n+1 • 5 bits value tag with 3 hours validity • UE checks value tag e. g. upon recovery from out of coverage Modification Period Concept BCCH modification period(n) BCCH modification period(n+1) Modification indication Updated information Sent via Paging message Copyright All Rights Reserved 30 / 122 LG Electronics RAN 2 Team

Usage of Paging Message Page one or more UEs Oh! I got a call My God! Emergency!! Paging ETWS primary / secondary Notificatio n Copyright All Rights Reserved System Info. Change Notificatio n 31 / 122 There will be something new in system information LG Electronics RAN 2 Team

Triggering of Connection Establishment Mobile Originating call RRC Connection establishment Get my call! Operator core network my friend I got a call Hello? Mobile Terminating Call Hey, get a call! RRC Connection establishment Operator core network paging my friend Copyright All Rights Reserved 32 / 122 LG Electronics RAN 2 Team

RRC Connection Establishment procedure UE NAS RLC/MAC/L 1 UE RRC e. NB NAS service request Access Barring check If not barred RRCConnection. Request Random Access msg 1 msg 2 RRCConnection. Request msg 3 RRCConnection. Setup msg 4 SRB 1 setup RRCConnection. Setup. Complete Copyright All Rights Reserved 33 / 122 RRCConnection. Setup Complete LG Electronics RAN 2 Team

LTE Access Class Barring e. g. ) one or more AC 11 -15 MT data/ signal Emergency Call MO signal MO data TRUE/ FALSE Emergency Call one or more AC 11 -15 1 0/ AC 11 X 1 1 0/ AC 12 AC 13 AC 14 X X 1 0/ 0/ AC 15 X X Access Probability Check Not Barred Access to the cell Copyright All Rights Reserved 34 / 122 LG Electronics RAN 2 Team

Measurements RRCConfiguration. Reconfgiuration - Measurement Configuration Plz measure what I order Perform measurement Measurement. Report - Measurement Result Neighboring cell is better HO Oh you need a handover or Self Organized Network This is the requested CGI for the PCI or This is my strongest cell(s) Copyright All Rights Reserved Automatic Neighbor Relationship 35 / 122 or Thanks for CGI reporting or Oh that is a strongest cell around you LG Electronics RAN 2 Team

Measurement Principles Single Measurement object for a given frequency Measurement objects are specified per RAT type Serving cell Detected cells E-UTRAN • Only when performing SON UTRAN CDMA 2000 GERAN Listed cells Layer 3 filtering on L 1 measurement results Inter-freq. measurement performed during idle period including measurement gaps Copyright All Rights Reserved 36 / 122 LG Electronics RAN 2 Team

Measurement Configuration Object Measurement object #0 Measurement object #1 Measurement object #2 ID ID 0 ID 1 ID 3 ID 2 • a single E-UTRA carrier frequency • a set of cells on a single UTRA carrier frequency • a set of GERAN carrier frequencies. • a set of cells on a single (HRPD or 1 x. RTT) carrier frequency. Copyright All Rights Reserved 37 / 122 Report Config Reporting Configuration #0 Reporting Configuration #1 Reporting Configuration #2 • Reporting criteria • Reporting format LG Electronics RAN 2 Team

Measurement Configuration & Report UE e. NB RRCConnection. Reconfiguration Measurement Configuration Measurement configuration A 1 A 2 A 3 B 1 B 2 (inter-RAT case) A 4 A 5 Offset Measurement Neighbor cell result Threshold 2 Threshold 1 Serving cell result Reporting Measurement. Report ID, Result Copyright All Rights Reserved 38 / 122 LG Electronics RAN 2 Team

Mobility Fundamentals Measurement Report RRC_CONNECTED UE mobility • Network controls UE mobility e. NB sends Handover command to UE RRC_IDLE UE mobility • UE based mobility UE performs Cell re-selection True mobile phone Copyright All Rights Reserved Reselection parameters 39 / 122 LG Electronics RAN 2 Team

Network based Mobility Principle Source e. NB Target e. NB 2. Measurement Report (1. Measurement) 3. HO command Moving connected UE Signal Strength Source e. NB Target e. NB Signal Strength HO region Copyright All Rights Reserved 40 / 122 LG Electronics RAN 2 Team

Intra-EUTRA Handover procedure Simplified Handover Procedure 1. Look at this. I need a handover to there Target e. NB Source e. NB UE 2. This is configuration info for the UE. Could you accept handover? Measurement report HO request 4. Go there!. Good luck~! 3. OK. Let him use this configuration at handover HO request Ack (HO command) HO command Random Access HO confirm 5. Mission completed Copyright All Rights Reserved 41 / 122 LG Electronics RAN 2 Team

Inter RAT Handover To-EUTRA Handover • RRCConnection. Reconfiguration sent via another RAT • Handover from GERAN or UTRAN From-EUTRA Handover • Handover To GERAN, UTRAN or CDMA 2000 • Cell Change Order to GERAN From EUTRA HO To-EUTRA HO Copyright Most UE behaviors are specified in target RAT Default configuration as a base configuration applied All Rights Reserved 42 / 122 LG Electronics RAN 2 Team

CS Fallback ¢ CSFB for serving voice call l Voice call is served by other CS RAT (UMTS, GSM) l Redirection or Handover to other RAT is performed Target RAT Solutions Release CS fallback to UMTS RRC Connection Release with Redirection without Sys Info Rel-8 RRC Connection Release with Redirection with Sys Info PS handover with DRB(s) Rel-9 RRC Connection Release with Redirection without Sys Info Rel-8 RRC Connection Release with Redirection with Sys Info Cell change order without NACC Rel-9 Cell change order with NACC Rel-8 PS handover Rel-8 CS fallback to GSM Copyright <TS 36. 300> All Rights Reserved 43 / 122 Rel-8 LG Electronics RAN 2 Team

RRC Failure Cases Radio Link Failure Intra-LTE handover Failure From E-UTRA mobility failure Integrity Check Failure RRC Reconfiguration Failure Connected Failure Detection RRC Connection Re-establishment procedure Connected Recovery Attempt Copyright All Rights Reserved 44 / 122 LG Electronics RAN 2 Team

Radio Link Failure & Recovery Radio Link Failure Declared U L Random Access Problem Indication from MAC U L Maximum retransmission at RLC D L Radio Link Problem Cell selection T 311 RRC Connection Re-establishment RRC_ Connected T 301 Go to Idle T 310 Failure of E-UTRA cell selection Connection Re-establishment Failure Copyright All Rights Reserved 45 / 122 LG Electronics RAN 2 Team

LTE MAC Protocol (Rel-8) Sung. Jun Park (sungjun. park@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2009. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

MAC – Vertical View RLC • HTTP, FTP, etc - IP • Security and Header compression • Framing and ARQ MAC • Multiplexing and Scheduling PHY • Physical layer processing App PDCP Copyright All Rights Reserved 47 / 122 LG Electronics RAN 2 Team

UE side MAC structure PCCH BCCH CCCH DTCH Logical Channel Prioritization (UL only) Control (De-) Multiplexing Random Access Control HARQ PCH Copyright BCH DL-SCH All Rights Reserved UL-SCH RACH 48 / 122 LG Electronics RAN 2 Team

PCCH PCH BCCH CCCH BCH PBCH DCCH D Tr ed af ica fi te c d em st Sy Pa gi ng In fo Co C m at on m co n tro on nn o R l I ec RC nfo ti on D Co ed nt ica ro te l d Channel Mapping DTCH for Rel-9 MBMS MCCH MTCH DL-SCH PDCCH MCH PMCH Downlink Copyright All Rights Reserved CCCH RACH PRACH DCCH DTCH UL-SCH PUCCH PUSCH Uplink 49 / 122 LG Electronics RAN 2 Team

MAC Functions UL-SCH data transfer DL-SCH data transfer Random Access Procedure Copyright All Rights Reserved UL Timing Control Buffer Status Reporting Scheduling Request Discontinuous Reception 50 / 122 Measurement Gap Handling Logical Channel Prioritization LG Electronics RAN 2 Team

Data Transfer (1/6) Purposes Means HARQ PDCCHoriented (dynamic scheduling) DL: Asynchronous adaptive PDCCH-less (semipersistent scheduling) UL: Synchronous non-adaptive Receive / transmit data from / to e. NB Copyright All Rights Reserved 51 / 122 LG Electronics RAN 2 Team

Data Transfer (2/6) DL Resource Assignment Dynamic Scheduling -Time-Freq. Resource Information -Transport Block Format -HARQ Process ID n me DL Assignment Reception via t ign s As tion L D cep Re UE’s C-RNTI Temporary C-RNTI RA-RNTI SI-RNTI DL Co Assi g nfi gu nme rat ion nt Semi-persistent Scheduling DL Assignment Configuration Copyright All Rights Reserved 52 / 122 LG Electronics RAN 2 Team

Data Transfer (3/6) UL Resource Grant Dynamic Scheduling -Time-Freq. Resource Information -Transport Block Format UL Grant on PDCCH with t n a Gr tion L U cep Re UE’s C-RNTI UL Grant on MAC signaling in Random Access Response UL Co Gran nfi gu t rat Semi-persistent Scheduling ion UL Grant configuration Copyright All Rights Reserved 53 / 122 LG Electronics RAN 2 Team

Data Transfer (4/6) Dynamic Scheduling DL DATA (DL-SCH) DL ASSIGN(PDCCH ) UL GRANT(PDCCH) UL DATA (UL-SCH) Resource Request LG Electronics RAN 2 Team 54 / 122 All Rights Reserved Copyright 4 TTI difference Time Same TTI UL DL DATA (DL-SCH) DL Time

Data Transfer (5/6) Semi-Persistent Scheduling DL DATA (DL-SCH) DL Time UL DATA (UL-SCH) UL Time Copyright All Rights Reserved 55 / 122 LG Electronics RAN 2 Team

Data Transfer (6/6) Semi-Persistent Scheduling configuration – DL case e. NB UE Pre-configuration by RRC Msg. E. g. Resources information , Transport Block Format PDCCH for SPS Activation E. g. Interval, No. of SPS-processes DL-SCH for SPS SPS resource release PDCCH for SPS De-activation PDCCH for SPS Activation DL-SCH for SPS Copyright All Rights Reserved 56 / 122 LG Electronics RAN 2 Team

Special Handling on UL HARQ (1/3) Sticky Grant for Adaptive HARQ Re Tx UL Tx x e. T r. R fo PRACH resrc. Frequency Same Phy. Resources Copyright CK NA H CC PD CK NA UE Re Tx e. NB All Rights Reserved Same Phy. Resources 57 / 122 Time LG Electronics RAN 2 Team

Special Handling on UL HARQ (2/3) Fake ACK Re Tx x e. T r. R fo UE H CC PD K AC CK NA UL Tx e. NB Data in HARQ buffer is kept Frequency PRACH resrc. Phy. Resources Time Copyright All Rights Reserved 58 / 122 LG Electronics RAN 2 Team

Special Handling on UL HARQ (3/3) TTI Bundling e. NB UE PDCCH for UL Grant 2 * HARQ RTT DL-SCH Tx NACK DL-SCH Tx Copyright All Rights Reserved 3 consecutive Re. Tx without feedbacks 59 / 122 3 consecutive Re. Tx without feedbacks LG Electronics RAN 2 Team

Random Access Procedure (1/4) Purposes Obtain timesynchronization Request uplink resources Copyright All Rights Reserved Initiation By PDCCH order Categorization Contention based Use cases Initial Access Radio Link/HO Failure Handover By MAC sublayer itself Contention Free based 60 / 122 UL/DL data arrival LG Electronics RAN 2 Team

Random Access Procedure (2/4) Contention based RA Contention Free based RA UE UE e. NB Random Access Preamble allocation Random Access Response (T-CRNTI) Random Access Preamble Random Access Response Msg 3 (C-RNTI or CR ID) Non-CCCH SDU case Applicable at ØHandover ØDL arrival e. NB CCCH SDU case PDCCH with C-RNTI Contention Resolution ID on DL-SCH HARQ Feedback Promotion of Temporary C-RNTI ØT-C-RNTI is promoted to C-RNTI when CR is successful Special HARQ Handling ØWinner: ACK ØLoser: No feedback Copyright All Rights Reserved 61 / 122 LG Electronics RAN 2 Team

Random Access Procedure (3/4) RA Preamble Set selection Total RA preamble set Non-dedicated RA preambles set Group. A e. g. 00 ~ xx Copyright Group. B e. g. xx ~ yy All Rights Reserved Dedicated RA preambles set • Selected by MAC (non-dedicated) • Signaled by PDCCH and RRC (dedicated) RA Preamble Group selection • Depending on Msg 3 size and pathloss, e. g. • If Msg 3 size > 56 bits and pathloss < 5 d. B Group. B • Otherwise Group. A e. g. yy ~ 63 62 / 122 LG Electronics RAN 2 Team

Random Access Procedure (4/4) RA Response reception • Selected PRACH resource and RA-RNTI are associated • One RA Response is intended for one or more UEs Configurable TTI window Selected PRACH resource PDCCH -Addressed by RA-RNTI PDSCH (RA Response) -Backoff Indicator -RA Preamble Id -TA command -UL grant -Temporary C-RNTI Time Copyright All Rights Reserved 63 / 122 LG Electronics RAN 2 Team

Buffer Status Report (1/2) Purposes Initiation By UL data arrival with higher priority Provide UE’s buffer status information to e. NB By periodic method (timer) By reliable method (timer) By padding Copyright All Rights Reserved 64 / 122 Formats Short BSR -1 byte * 1 LCG ID + 1 LCG info. Long BSR -3 bytes * No LCG ID + 4 LCGs info. LG Electronics RAN 2 Team

Buffer Status Report (2/2) 1 2 Start (Re)start Periodic Timer 3 Restart gr an t Re. Tx Timer Expire 4 Restart BS R U L BS R Triggering of BSR 5 Expire Buffer Trigger event Low Prio High Prio Time • 1. Data arrival in empty buffer • 2. Higher priority data arrival • 3. Padding exists • 4. Periodic timer expiry • 5. Re. Tx timer expiry (restart at new uplink grant) MAC PDU Padding Copyright All Rights Reserved 65 / 122 LG Electronics RAN 2 Team

Scheduling Request (1/3) Purposes Request UL resources for carrying BSR Copyright All Rights Reserved Initiation By BSR when no UL resources are available 66 / 122 Means By PUCCH (D-SR) if configured By Random Access Procedure LG Electronics RAN 2 Team

Scheduling Request (2/3) SR procedure (D-SR case) UE e. NB Triggered BSR D-SR transmission UL Grant BSR transmission UL Grant Actual data transmission Copyright All Rights Reserved 67 / 122 LG Electronics RAN 2 Team

Scheduling Request (3/3) D-SR failure UE e. NB Wrong power control # of D-SR Tx =1 D-SR transmission # of D-SR Tx =2 D-SR transmission # of D-SR Tx =3 D-SR transmission Max. Tx reached • Release UL resource • Initiate RA procedure Random Access Preamble Copyright All Rights Reserved 68 / 122 LG Electronics RAN 2 Team

UL Timing Control (1/2) Purposes Maintain orthogonality between users Copyright All Rights Reserved Means By Command & Timer -Timing Advance Command -Time Alignment Timer 69 / 122 States In sync Out of sync LG Electronics RAN 2 Team

UL Timing Control (2/2) Reception of Time Alignment Command Out of Sync. - Release any UL resources - Flush all HARQ buffers Copyright All Rights Reserved Start Time Alignment Timer In Sync. Expiry of Time Alignment Timer 70 / 122 Reception of Time Alignment Command Restart Time Alignment Timer LG Electronics RAN 2 Team

Discontinuous Reception (DRX) (1/4) Purposes Means Types Save UE’s power consumption By various timers Short DRX Controlling UE’s PDCCH monitoring activities Copyright All Rights Reserved On duration T HARQ RTT T DRX Re. Tx T DRX Inactivity T DRX Short Cycle T Long DRX 71 / 122 LG Electronics RAN 2 Team

Discontinuous Reception (DRX) (2/4) Long DRX opportunity APP Time Loading Time Short DRX opportunity Reading Time Short DRX opportunity Time Copyright All Rights Reserved 72 / 122 LG Electronics RAN 2 Team

Discontinuous Reception (DRX) (3/4) Tx Re. Tx Short DRX opportunity Tx Long DRX opportunity Short DRX opportunity Time On Duration T HARQ RTT T DRX Re. Tx T Restart at DRX Inactivity T expiry DRX Inactivity T Short Cycle T Active Time (UE monitors PDCCH) = On Duration T + DRX Re. Tx T + DRX Inactivity T Copyright All Rights Reserved 73 / 122 LG Electronics RAN 2 Team

Discontinuous Reception (DRX) (4/4) DRX state transition Cont. Rx DRX Inactivity T expiry or DRX Command MAC CE DL/UL Assignment Short DRX Long DRX Short Cycle T expiry Copyright All Rights Reserved 74 / 122 LG Electronics RAN 2 Team

Measurement Gap (MG) (1/3) Purposes Impacted Areas UL/DL HARQ Measure different frequencies No Tx/RX during MG Random Access Copyright All Rights Reserved 75 / 122 LG Electronics RAN 2 Team

Measurement Gap (MG) (2/3) HARQ operation colliding with MG MG No PUCCH No PUSCH No PDCCH Copyright All Rights Reserved MG MG at reception of PHICH : treated as ACK 76 / 122 UL -S C Tx H UL -S CH Tx UL -S CH UE CK NA FB Tx e. NB MG MG at retransmission : treated as NACK LG Electronics RAN 2 Team

Measurement Gap (MG) (3/3) Random Access Procedure colliding with MG MG MG Ms g 3 MG RACH has priority over MG RACH and MG have equal priority All Rights Reserved MG MG at Msg 2/3 MG at Msg 1 Copyright MG K AC UE g 2 Ms Ms g 1 e. NB 77 / 122 LG Electronics RAN 2 Team

Logical Channel Prioritization (1/2) Purposes Allocate transmitting resources to logical channels Copyright All Rights Reserved Means Parameter Logical Channel Priority Token Bucket Prioritized Bit Rate 78 / 122 LG Electronics RAN 2 Team

Logical Channel Prioritization (2/2) LTE Prioritization (Relative Priority) UMTS TFC Selection (Absolute Priority) RB 1 (P 1) RB 2 (P 2) RB 1 (P 1) RB 3 (P 3) RB 2 (P 2) PBR 1 PBR 2 Starvation 1 Transmitting Resource Copyright All Rights Reserved 2 3 PBR 3 4 Transmitting Resource 79 / 122 LG Electronics RAN 2 Team

LTE RLC Protocol (Rel-8) Seung. June Yi (seungjune. yi@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2009. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

RLC – Vertical View RLC • HTTP, FTP, etc - IP • Security and Header compression • Framing and ARQ MAC • Multiplexing and Scheduling PHY • Physical layer processing App PDCP Copyright All Rights Reserved 81 / 122 LG Electronics RAN 2 Team

RLC TM RLC SDU “T” = “Transparent” • No function “SDU” = “PDU” • No header • No segmentation • No concatenation TM RLC Application • RRC message transmission while RRC connection is (virtually) not established • System Information Broadcast • Paging • RRC Connection (Re-establishment) RLC PDU Copyright All Rights Reserved 82 / 122 LG Electronics RAN 2 Team

RLC model - TM UE/ENB TM-SAP ENB/UE Radio Interface TM-SAP Transmitting Receiving TM-RLC entity Transmission Buffer BCCH/PCCH/CCCH Copyright All Rights Reserved 83 / 122 LG Electronics RAN 2 Team

RLC UM “U” means “Unacknowledged” RLC SDU • No feedback from receiver • Lossy transmission “RLC SDU” ≠ “RLC PDU” • RLC Header is included • Segmentation can be applied • Concatenation can be applied UM RLC Application HDR RLC SDU 1 • Streaming type user data transmission (error tolerant, delay intolerant) • Vo. IP • Audio/Video streaming RLC SDU 2 RLC PDU Copyright All Rights Reserved 84 / 122 LG Electronics RAN 2 Team

RLC model - UM UE/ENB Radio Interface UM-SAP ENB/UE UM-SAP Receiving Transmitting Transmission Buffer UM-RLC SDU Reassembly entity Segmentation & Concatenation Remove RLC header Add RLC header Reception Buffer & HARQ Reordering DCCH/DTCH Copyright All Rights Reserved 85 / 122 LG Electronics RAN 2 Team

RLC AM “A” means “Acknowledged” RLC SDU • Feedback from receiver • Retransmission based on feedback • Lossless transmission “RLC SDU” ≠ “RLC PDU” • • AM RLC Header is included Segmentation can be applied Concatenation can be applied Re-segmentation can be applied Application HDR RLC SDU 1 • Interactive/Background type user data transmission (error intolerant, delay tolerant) • Web browsing • File download • RRC message transmission while RRC connection is established • Most RRC messages RLC SDU 2 RLC PDU Copyright All Rights Reserved 86 / 122 LG Electronics RAN 2 Team

RLC model - AM AM-SAP Transmission Buffer Segmentation & Concatenation RLC Control Retransmission Buffer SDU Reassembly Remove RLC header Reception Buffer & HARQ reordering Add RLC header Routing DCCH/DTCH Copyright All Rights Reserved DCCH/DTCH 87 / 122 LG Electronics RAN 2 Team

RLC – SAR RLC SDU 1 RLC SDU 2 Concatenation concatenation Header RLC SDU 1 RLC SDU 2 RLC PDU 1 • To multiplex together part of multiple RLC SDUs into RLC PDU • To reduce unused resources Segmentation • Dividing RLC SDU to fit into the available space of RLC PDUs RLC SDU 3 Segmentation Header RLC SDU 3 a RLC PDU 2 Copyright All Rights Reserved Header RLC SDU 3 b RLC PDU 3 88 / 122 LG Electronics RAN 2 Team

RLC – SAR RLC SDU 1 RLC SDU 2 RLC SDU 1 • Receiver should know how to reassemble RLC SDUs out of RLC PDUs Length Indicator (LI) ? RLC PDU LI Header length RLC SDU 1 RLC SDU 2 RLC PDU Copyright All Rights Reserved Receiver dilemma 89 / 122 • Length Indicator is used to indicate the size of each component RLC SDUs within RLC PDU • There is no LI for the last component RLC SDU within RLC PDU LG Electronics RAN 2 Team

RLC – SAR RLC SDU 1 RLC SDU 2 RLC SDU 1 ? • Receiver should know how to reassemble RLC SDUs out of RLC PDUs Framing Info (FI) RLC PDU Segmented? FI Header RLC SDU 1 RLC SDU 2 Receiver dilemma RLC SDU 3 • Framing Info is used to indicate the segmentation status for the First and Last RLC SDUs within a RLC PDU Copyright All Rights Reserved 90 / 122 LG Electronics RAN 2 Team

RLC – FI example Original HDR RLC SDU 1 RLC SDU 2 RLC SDU 3 Original PDU FI=00 • First byte is the first byte of a SDU • Last byte is the last byte of a SDU FI=01 FI=00 RLC SDU 1 RLC SDU 2 FI=01 RLC SDU 2 FI=10 RLC SDU 2 1’ FI=11 RLC SDU 2 1’ RLC SDU 3’ PDU Segments Copyright All Rights Reserved 91 / 122 • First byte is the first byte of a SDU • Last byte is not the last byte of a SDU FI=10 • First byte is not the first byte of a SDU • Last byte is the last byte of a SDU FI=11 • First byte is not the first byte of a SDU • Last byte is not the last byte of a SDU LG Electronics RAN 2 Team

RLC AM-Basic ARQ PDU 1 Event 1 Poll Event 1 ACK 1 PDU 2 PDU 3 • TX sends a Poll to request status report • RX send status report when Poll is received Event 2 NACK 2 ACK 3 PDU 2 Transmitter Copyright All Rights Reserved • When RX detects a missing PDU, it sends a status report to request a retransmission. Receiver 92 / 122 LG Electronics RAN 2 Team

Impact of N-CH SAW HARQ (1) PDU 1 PDU 2 Transmitter NACK Receiver PDU 2 Copyright All Rights Reserved ← Out of Order → 93 / 122 PDU 1 LG Electronics RAN 2 Team

Impact of N-CH SAW HARQ (2) PDU 1 PDU 2 PDU 1 PDU 3 PDU 2 NACK PDU 3 NACK 2 ACK 3 PDU 2 Receive MAC Receiver RLC PDU 2 Duplicate transmission Transmitter RLC Copyright Transmitter MAC All Rights Reserved 94 / 122 LG Electronics RAN 2 Team

Modified ARQ(1) PDU 1 PDU 2 PDU 1 NACK PDU 3 Start PDU 3 PDU 2 Stop HARQ Reordering Transmitter RLC Copyright Transmitter MAC All Rights Reserved Receiver MAC 95 / 122 Receiver RLC LG Electronics RAN 2 Team

Modified ARQ(2) PDU 1 PDU 2 PDU 1 NACK PDU 3 Start PDU 3 NACK 2 ACK 3 PDU 2 Transmitter RLC Copyright PDU 2 Transmitter MAC All Rights Reserved Receiver MAC 96 / 122 expiry Delayed Status Reporting Receiver RLC LG Electronics RAN 2 Team

Re-ordering PDU 1 PDU 2 PDU 3 PDU 2 Reordering PDU 2 PDU 3 Transmitter MAC Copyright All Rights Reserved Receiver MAC 97 / 122 Receiver RLC LG Electronics RAN 2 Team

Delay control PDU 1 PDU 2 PDU 3 PDU 1 Reordering PDU 3 Start expiry PDU 3 Transmitter MAC Copyright All Rights Reserved Receiver MAC 98 / 122 Receiver RLC LG Electronics RAN 2 Team

RLC Re-segmentation Flexible size Transmitter RLC Transmitter MAC Size: 900 Receiver RLC PDU 1 Size: 900 Size: 500 PDU 2 Size: 500 NACK PDU 1 Size: 900 Size: 300 PDUseg 1 Size: 300 Size: 600 PDUseg 2 Size: 600 PDU 1 Size: 900 • Used to maximize radio efficiency • Reduces unnecessary header overhead Re-segmentation • Used to transmit part of the original RLC PDU when the size of original PDU is not supported at the time of retransmission New PDU for retransmission PDU segment Radio Interface Copyright All Rights Reserved 99 / 122 LG Electronics RAN 2 Team

RLC Re-segmentation Original RLC SDU 1 ( size : 600 ) Original RLC PDU 1 st PDU Segment Original RLC SDU 2 ( size : 300 ) LI=600 SN=1 PDU Header RLC SDU 1 ( size : 600 ) RLC SDU 2 ( size : 300 ) offset SO=0 SN=1 RLC SDU 1 ( size : 500 ) PDU Segment Header 2 nd PDU Segment LI=100 SO=500 SN=1 RLC SDU 1 ( size : 100 ) RLC SDU 2 ( size : 300 ) PDU Segment Header Copyright All Rights Reserved 100 / 122 LG Electronics RAN 2 Team

Detection of abnormality RETX_COUNT PDU 1 Initial TX ACK First N RETX_COUNT=0 PDU 1 Re TX RETX_COUNT=1 • when first NACK is received PDU 1 Incremented RRC RETX_COUNT=2 PDU 1 RETX_COUNT=3 =MAX_RETX_THRESHOLD Receiver Error Reporting Transmitter RLC Copyright • Counts the number of retransmission is considered • Prevent endless retransmission Initialized All Rights Reserved RLC 101 / 122 • When NACK is received, AND, • if it (the AMD PDU or the portion of the AMD PDU that is considered for retransmission) is not pending for retransmission already, or a portion of it is not pending for retransmission already LG Electronics RAN 2 Team

Push window/pull window NOT RECEIVED PDU 6 RECEIVING WINDOW PDU 1 PDU 2 PDU 3 PULL Received PDU 4 RECEIVING WINDOW PDU 1 PDU 2 PDU 3 PDU 4 PDU 5 PDU 6 Pull Window • Reception of SN above window advances the window. • Used in UM. SN outside of a window advances the window. Push Window • Reception of lowest SN within a window advances a window • Used in AM. SN outside of a window is discarded. PDU 1 Received RECEIVING WINDOW PDU 1 PDU 2 PDU 3 RECEIVING WINDOW PDU 4 PDU 1 PDU 2 PDU 3 PDU 4 PDU 5 PUSH Copyright All Rights Reserved 102 / 122 LG Electronics RAN 2 Team

LTE PDCP Protocol (Rel-8) Seung. June Yi (seungjune. yi@lge. com) Click to to edit Master subtitle style October 27, 2010 Copyright Notification . No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. ⓒ 2009. LG 3 GPP RAN 2 team. All rights reserved. LG Electronics RAN 2 Team

PDCP – Vertical View RLC • HTTP, FTP, etc - IP • Header compression and Security • Framing and ARQ MAC • Multiplexing and Scheduling PHY • Physical layer processing App PDCP Copyright All Rights Reserved 104 / 122 LG Electronics RAN 2 Team

PDCP Role PDCP SDU Header Compression • Increase radio efficiency Security Management PDCP • Ciphering • Integrity protection Selective Forwarding • Lossless and efficient HO support PDCP PDU Copyright All Rights Reserved 105 / 122 LG Electronics RAN 2 Team

PDCP model PDCP-SAP SDU numbering Re-ordering Header Compression Header Decompression Integrity Protection Integrity Verification Ciphering Deciphering C-SAP Add PDCP header Remove PDCP header Radio Bearer RLC UM/TM-SAP Copyright All Rights Reserved RLC UM/TM-SAP 106 / 122 RLC AM-SAP RLC Sub-layer LG Electronics RAN 2 Team

Header Compression (1) SRC Address: x. x Dest. Address: y. y Header checksum IP Header User datagram • Many packets have identical information • Transmitting same information is the root of inefficiency IP Packet 1 Identical Information Protocols SRC Address: x. x Dest. Address: y. y Header checksum IP Header Copyright Header Compression User datagram • Not specified in 36. 323 • A black box approach IP Packet 2 All Rights Reserved • Framework: RFC 4995 • Profiles: RFC 4815/3095/etc Implementation 107 / 122 LG Electronics RAN 2 Team

Header Compression (2) IP Packet 1 Context setup SRC: x. x Dest: y. y Payload IR Packet Header checksum • Used to establish/refresh Context • Include full header information • Different Contexts use separate CIDs SRC: x. x Header checksum IP Packet 2 IR packet Context Dest: y. y Compression Payload compressed Packet + De-Compression SRC: x. x Dest: y. y Payload Header checksum Compressed Packet • After Context establishment, only changed information is transmitted Standalone packet Feedback Header Compressor Copyright All Rights Reserved Header Decompressor 108 / 122 • Feedback LG Electronics RAN 2 Team

Header Compression (3) Two Types of PDUs D/C=D PDCP SN PDCP PDU Header • Header (de)compression entity generates two types of packets Data PDCP PDU Payload Compressed Packet D/C=C PDU Type = feedback PDCP PDU Header Data (ROHC feedback packet) PDCP PDU Payload • Related to PDCP SDU • Have a SN • May include feedback Standalone packet • Not related to PDCP SDU • No PDCP SN • Not ciphered Copyright All Rights Reserved 109 / 122 LG Electronics RAN 2 Team

Security – Ciphering (1) Orig. Data Key. Stream 1 Generator 1 1 1 0 1 0 0 Unsuccessful decoding Copyright 0 Purpose • Prevent unauthorized user from seeing the content of communication Ciphered data + (xor) 1 0 0 + (xor) 0 Decipher engine 1 1 Cipher engine Incorrect keystream 1 0 All Rights Reserved 0 1 0 0 Decipher engine + (xor) 1 0 0 • Apply Keystream to the original data De-ciphering • Apply Keystream to the received data 0 Successful decoding 110 / 122 LG Electronics RAN 2 Team

Security – Ciphering (2) Key. Stream Generator Key count bearer Direction Length • Transmitter and receiver should generate identical key stream Input • Unique generation against replay-attack • Key (Ck) • Count: • instance of generation • HFN + SN • Bearer: ID of bearer • Direction: UL/DL • Length Key. Stream Generator Key stream Copyright All Rights Reserved 111 / 122 LG Electronics RAN 2 Team

Security – Integrity Protection (1) Key count bearer Direction Auth Code Generator Orig. MSG Key count bearer Transmitter MAC-I MACI Air Interface All Rights Reserved • Calculates unique value based on the message • Attaches the value to the end of message Receiver Direction Auth Code Generator Copyright Rx MAC-I • Used to detect whether a text is tampered during delivery. + Mac-I Orig. MSG Rx MSG Integrity Protection x. Mac-I Compare 112 / 122 • Calculate unique value based on the received message • Compare the calculated value to the received value LG Electronics RAN 2 Team

Security – Integrity Protection (2) PDCP SN Data MAC-I PDCP PDU Header PDCP PDU Payload Security Info PDCP SN PDCP PDU Header Copyright All Rights Reserved Integrity Protection • Applied only to SRB 2 formats Data • MAC-I field is used for PDCP PDUs over SRBs • MAC-I field is not used for PDCP PDUs over DRBs PDCP PDU Payload 113 / 122 LG Electronics RAN 2 Team

Data Handling at handover (DL) UMTS Cumulative Forwarding Source RNC PDCP 1 2 3 4 2 3 5 4 Target RNC PDCP 5 2 2 3 4 3 1 1 3 Wasteful retransmission 5 UE PDCP LTE Selective Forwarding Source e. NB PDCP 1 2 5 3 4 2 5 Target e. NB PDCP 4 2 2 3 1 1 3 4 Reordering 5 Cumulative Forwarding • During HO, Source RNC forwards to Target RNC all SDUs from the first SDU not acknowledged by UE, and UE discards received SDUs from the first missing SDU • After HO, UE receives SDUs from Target RNC from the first missing SDU Selective Forwarding • During HO, Source e. NB forwards to Target e. NB only SDUs not acknowledged by UE • After HO, UE receives not yet received SDUs from Target e. NB, and performs reordering UE PDCP Copyright All Rights Reserved 114 / 122 LG Electronics RAN 2 Team

Impact of Incomplete information (1) PDU 1 PDU 2 PDU 3 PDU 1 PDU 3 NACK 2 ACK 1, 3 PDU 4 PDU 5 Handover PDU 3 PDU 5 Transmitting PDCP Copyright Transmitting RLC All Rights Reserved Receiving RLC 115 / 122 Receiving PDCP LG Electronics RAN 2 Team

Impact of Incomplete information (2) 1 2 3 4 Incomplete information 5 Selective Forwarding Source e. NB PDCP 1 2 3 4 Target e. NB PDCP 2 5 1 2 3 4 5 3 1 1 3 5 UE PDCP Wasteful retransmission Copyright All Rights Reserved 116 / 122 • The source e. NB’s understanding of successful transmission is not always correct or up-to-date. • Loss of Status Report or delay in transmission of status report causes incomplete information Effect • Unnecessarily, more Data are forwarded from Se. NB to Te. NB • Unnecessarily, more Data are transmitted from Te. NB to UE LG Electronics RAN 2 Team

Status Reporting (DL) 1 2 3 4 Status Reporting 5 Selective Forwarding Source e. NB PDCP 1 2 3 4 Target e. NB PDCP 2 5 1 2 3 4 5 1 3 4 NACK 2, 4 ACK 1, 3, 5 Copyright 1 All Rights Reserved 3 • To fill the gap of the incomplete information, when a UE accesses to Te. NB, the UE transmit PDCP status Report • PDCP Status Report indicates the missing PDCP PDUs and successfully received PDCP PDUs Effect • Unnecessary transmission is prevented 5 UE PDCP 117 / 122 LG Electronics RAN 2 Team

Data Handling at handover (UL) UMTS No Forwarding Source RNC PDCP 1 3 Target RNC PDCP 5 1 2 3 4 5 UE PDCP LTE 3 3 Target e. NB PDCP 5 5 3 5 Reordering 1 2 3 4 5 UE PDCP Copyright All Rights Reserved • During HO, Source RNC does not forward any SDUs to Target RNC • After HO, UE transmits to Target RNC from the first SDU not acknowledged by Source RNC Selective Retransmission Selective Forwarding Source e. NB PDCP 1 Wasteful retransmission Cumulative Retransmission 118 / 122 • During HO, Source e. NB forwards to Target e. NB all SDUs from the first missing SDU • After HO, UE transmits to Target RNC only the SDUs not acknowledged by Source RNC, and Target RNC performs reordering LG Electronics RAN 2 Team

Status Reporting (UL) 3 5 Selective Forwarding Source e. NB PDCP 1 3 Target e. NB PDCP 2 NACK 2, 4 ACK 1, 3, 5 5 3 1 4 1 2 3 4 All Rights Reserved • To fill the gap of the incomplete information, when a UE accesses to Te. NB, the Te. NB transmit PDCP status Report • PDCP Status Report indicates the missing/received PDCP PDUs Effect • Unnecessary transmission is prevented 5 UE PDCP Copyright Status Reporting 119 / 122 LG Electronics RAN 2 Team

PDCP Status Report D/C=C FMS PDU Type = status report Bitmap FMS • First missing SN PDCP PDU Header PDCP PDU Payload Bitmap Example NOT RECEIVED … … PDU 1 PDU 2 PDU 3 RECEIVED PDU 4 PDU 5 PDU 6 D/C=C 0 PDU Type = status report 0 0 0 1 0 0 FMS=1 Bitmap PDCP PDU Header Copyright All Rights Reserved PDCP PDU Payload 120 / 122 0 • The first bit indicates reception status of SN = FMS+1. • The Nth bit indicates reception status of SN=FMS+N. • ‘ 1’ means retransmission is not needed • ‘ 0’ means retransmission needed. • The size of ‘bitmap’ field is multiple of 8 bit. LG Electronics RAN 2 Team

Delay control RRC MSG IP Packet Discard Timer PDCP Start SDU Buffer start sto p X Process expir y RRC MSG IP Packet Stop Expiry RLC SUCCESSFUL DELIVERY Copyright All Rights Reserved • Related to buffer/delay management • Defines maximum wait time DISCARD INFORMATION 121 / 122 • When a PDCP SDU is received from upper layer, discard timer for the SDU is started. • When a discard timer expires, either the PDCP SDU is discarded or indication is sent to lower layer. LG Electronics RAN 2 Team

Thank You!! Authorized by LG Electronics 3 GPP RAN 2 Team LG RAN 2 team blog: lgeran 2. tistory. com Copyright All Rights Reserved 122 / 122 LG Electronics RAN 2 Team