1. From LTE to 5G New Radio (NR): Layer 2 Aspects
不要用演進概括
華碩電腦
陳威宇 專員

2. Outline Introduction of 5G NR SDAP (Service Data Adaptation Protocol)
PDCP (Packet Data Convergence Protocol)
RLC (Radio Link Control)
MAC (Medium Access Control)
Future Works in 5G NR Layer 2

3. Introduction of 5G NR Introduction of 5G NR SDAP PDCP RLC MAC
5G NR Requirements
5G NR Layer 2
SDAP
PDCP
RLC
MAC
Future Works in 5G NR Layer 2

4. 5G NR Requirements DL 4 ms UL 4 ms DL 0.5 ms UL 0.5 ms 1-10-5
Battery life:
10~15 years
[1]

5. 5G NR Layer 2 LTE vs NR LTE User Plane Protocol NR User Plane Protocol
PDCP子層負責的主要功能有資料封包的標頭(Header)壓縮與解壓縮、資料加密/解密、資料完整性的保護。  
RLC子層後，該子層主要的功能為對資料SDU進行切割及組合，使之成為適當大小的PDU。RLC子層負責的另一項重要工作則是在封包遺失時進行自動重傳請求(Automatic Repeat Request, ARQ)。  
MAC子層將接手執行排程(Scheduling)、多工(Multiplexing)等任務，以組成MAC子層PDU。此外，在MAC子層端，為防止RLC提供的PDU遺失，還具備混合式自動回覆請求重傳(HARQ)等功能。  

6. Service Data Adaptation Protocol
Introduction of 5G NR
SDAP
Introduction of SDAP
Reflective QoS
PDCP
RLC
MAC
Future Works in 5G NR Layer 2

7. Introduction of SDAP (1/2)
Introduce QoS-flow NR
LTE Reason NR
LTE
Flexibility for base station to control mapping between radio bearers(RB) and flows based on radio resource management (RRM) policy

8. Introduction of SDAP (2/2)
SDAP layer (User plane)

9. To minimize the control signaling between network and UE
Reflective QoS
AS reflective QoS DL
Application
QoS rule 2
SDAP 1
SDF flow1
QoS flow1
RB1
SDF flow2
QoS flow1 3 4
動畫; 數字 箭頭 清晰化 UL
To minimize the control signaling between network and UE

10. Packet Data Convergence Protocol
Introduction of 5G NR
SDAP
PDCP
PDCP Duplication
RLC
MAC
Future Works in 5G NR Layer 2
簡寫 要說明

11. PDCP Duplication (1/2)
To increase reliability of Signaling Radio Bearer (SRB) and Data Radio Bearer (DRB) for URLLC
Data
Data
PDCP
PDCP
Data
Data
Data
Data
RLC
RLC
RLC
RLC
MAC
MAC
MAC
MAC
Data
Data

12. PDCP Duplication (2/2) Carrier Aggregation Dual Connectivity
CA ; DC deployment concept; LTE
Cell1
Cell1
Cell1
Cell3
Cell2
Cell2
Cell2
Cell4

13. Radio Link Control Introduction of 5G NR SDAP PDCP RLC MAC
RLC Acknowledged Mode (AM) NACK Range
MAC
Future Works in 5G NR Layer 2
簡寫 要說明

14. No concatenation in RLC
RLC AM NACK Range
New field in status PDU – NACK range
Contiguous RLC PDUs loss will occur in MAC PDU transmission failure case
No concatenation in RLC
LTE 和NR 比對圖;
LTE - > reason - > NR vs LTE

15. Medium Access Control Introduction of 5G NR SDAP PDCP RLC MAC
MAC Protocol Data Unit (PDU) Format
Logical Channel Prioritization (LCP) Enhancement
Scheduling Request (SR) Enhancement
On-demand System Information Mechanism
Future Works in 5G NR Layer 2
簡寫 要說明

16. For reducing processing time, preprocessing is allowed.
MAC PDU Format (1/2)
For reducing processing time, preprocessing is allowed.
UL format
LTE NR

17. MAC PDU Format (2/2)
DL format
LTE NR

18. LCP Enhancement (1/2)
Logical Channel Prioritization (LCP) is a procedure to create MAC PDU for transmission
LTE
LC1
LC2
LC1
LC2
Logical channel 1:
- Priority 1
Logical channel 2:
- Priority 2
Grant
簡介LCP的功能;LTE ; LTE vs NR
LCP
MAC PDU

19. LCP Enhancement (2/2)
For achieving URLLC service requirement Latency≦0.5ms
Logical channel scheduling limitation
Sub-Carrier Spacing (SCS)
Time information
Cell NR
LC1
LC2
LC1
LC2
Logical channel 1:
- Priority 1
- SCS index 1
簡介LCP的功能;LTE ; LTE vs NR
Logical channel 2:
- Priority 2
- SCS index 2
Grant on SCS 2
LCP
MAC PDU

20. For achieving URLLC service requirement
SR Enhancement
Scheduling Request (SR) is for UE to autonomously request resource on data channel
Multiple SR configurations associated with different resource demands
SR configuration 1
SR1
SR configuration 2
SR2 UE BS UE BS SR
SR1 / SR2
Uplink grant
Uplink grant1/
Uplink grant2
BSR + data
BSR + data1/data2
For achieving URLLC service requirement
Latency≦0.5ms

21. On-demand System Information (1/2)
LTE system information
Periodically broadcast
NR System information
Minimum system information (SI)
Necessary system information for initial access
Other system information (on-demand)
LTE SI mechanism info.
Reduce unnecessary broadcast transmissions

22. On-demand System Information (2/2)
For requesting Other SI
Transmit system information request (RRC_CONNECTED)
RA Msg1 based (RRC_IDLE/ RRC_INACTIVE)
RA Msg3 based (RRC_IDLE/ RRC_INACTIVE)
Msg1 based Msg3 based UE BS UE BS
Minimum SI
Minimum SI
Msg1
Compromise
Special Msg1 for Other SI
Msg2
Msg2
Msg3(SI request)
Other SI
Other SI

23. Future Works Introduction of 5G NR SDAP PDCP RLC MAC
Future Works in 5G NR Layer 2
簡寫 要說明

24. Future Works in 5G NR Layer 2
V2X Communication/Sidelink Communication
Impact of enhancements in NR
Impact of any new service requirements
Massive Machine Type Communication (mMTC)
Power saving mechanism
Small data transmission
[2]
[3]

25. References
IMT Vision – Framework and overall objectives of the future development of IMT for 2020 and beyond
5G-PPP White Paper on Automotive Vertical Sector
Expanding the horizon of Mobile networks for Internet of Things, Hammad Tariq,
TS running CR
TS running CR
TS running CR TS

26. Thank You!