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1 3GPP LTE presentation 3GPP TSG RAN Chairman 3GPP TSG RAN Chairman 3GPP LTE presentation Kyoto May 22rd 2007.

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Presentation on theme: "1 3GPP LTE presentation 3GPP TSG RAN Chairman 3GPP TSG RAN Chairman 3GPP LTE presentation Kyoto May 22rd 2007."— Presentation transcript:

1 1 3GPP LTE presentation 3GPP TSG RAN Chairman 3GPP TSG RAN Chairman 3GPP LTE presentation Kyoto May 22rd 2007

2 2 3GPP LTE presentation Presentation Overview –LTE Introduction –Network Architecture –The access network Physical Layer Layer 2 and above over the radio interface –Control Plane –User Plane Interface towards the Core Network –Conclusion

3 3 3GPP LTE presentation LTE targets Significantly increased peak data rates Increased cell edge bitrates Improved spectrum efficiency Improved latency Scaleable bandwidth Reduced CAPEX and OPEX Acceptable system and terminal complexity, cost and power consumption Compatibility with earlier releases and with other systems Optimised for low mobile speed but supporting high mobile speed

4 4 3GPP LTE presentation Peak data rate Goal: significantly increased peak data rates, scaled linearly according to spectrum allocation Targets: –Instantaneous downlink peak data rate of 100Mbit/s in a 20MHz downlink spectrum (i.e. 5 bit/s/Hz) –Instantaneous uplink peak data rate of 50Mbit/s in a 20MHz uplink spectrum (i.e. 2.5 bit/s/Hz)

5 5 3GPP LTE presentation Mobility The Enhanced UTRAN (E-UTRAN) will: –be optimised for mobile speeds 0 to 15 km/h –support, with high performance, speeds between 15 and 120 km/h –maintain mobility at speeds between 120 and 350 km/h and even up to 500 km/h depending on frequency band –support voice and real-time services over entire speed range with quality at least as good as UTRAN

6 6 3GPP LTE presentation Spectrum issues Spectrum flexibility –E-UTRA to operate in 1.25, 1.6, 2.5, 5, 10, 15 and 20 MHz allocations…hence allowing different possibilities for re- farming already in use spectrum –uplink and downlink… –paired and unpaired Co-existence –with GERAN/3G on adjacent channels –with other operators on adjacent channels –with overlapping or adjacent spectrum at country borders –Handover with UTRAN and GERAN –Handover with non 3GPP Technologies (CDMA 2000, WiFi, WiMAX)

7 7 3GPP LTE presentation Network Architecture

8 8 3GPP LTE presentation ePDG Evolved Packet Core GPRS Core Trusted non 3GPP IP Access WLAN 3GPP IP Access S2b WLAN Access NW S5b IASA S5a SAE Anchor 3GPP Anchor S4 SGi Evolved RAN S1 Op. IP Serv. (IMS, PSS, etc…) Rx+ GERAN UTRAN Gb Iu S3 MME UPE HSS PCRF S7 S6 SGSN S2a MME and UPE have been split in two entities at the last SA

9 9 3GPP LTE presentation The access network Generality –The access network is simplified and reduce to only the Base Station called eNode B –Physical layer is based on SC FDMA for the Uplink and OFDMA for the Downlink –Two modes FDD and TDD considered –MBMS part of the study –Ciphering is handled within the eNode B

10 10 3GPP LTE presentation Physical Layer –Overview

11 11 3GPP LTE presentation Physical layer details –The Layer 1 is defined in a bandwidth agnostic way, allowing the LTE Layer 1 to adapt to various spectrum allocations. –The generic radio frame for FDD and TDD has a duration of 10ms and consists of 20 slots with a slot duration of 0.5ms. Two adjacent slots form one sub-frame of length 1ms. A resource block spans either 12 sub-carriers with a sub-carrier bandwidth of 15kHz or 24 sub-carriers with a sub-carrier bandwidth of 7.5kHz each over a slot duration of 0.5ms. –An additional framing is defined for TDD owing backward compatibility with TD SCDMA

12 12 3GPP LTE presentation Physical Layer details (continued) –The physical channels defined in the downlink are the Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH) and the Common Control Physical Channel (CCPCH). The physical channels defined in the uplink are the Physical Uplink Shared Channel (PUSCH) and the Physical Uplink Control Channel (PUCCH). –In addition, signals are defined as reference signals, primary and secondary synchronization signals or random access preambles. –The modulation schemes supported in the downlink are QPSK, 16QAM and 64QAM, and in the uplink QPSK, 16QAM and 64QAM. The Broadcast channel use only QPSK

13 13 3GPP LTE presentation Physical Layer (Continued) –The channel coding scheme for transport blocks in LTE is Turbo Coding with a coding rate of R=1/3, two 8-state constituent encoders and a contention-free quadratic permutation polynomial (QPP) turbo code internal interleaver. Trellis termination is used for the turbo coding. Before the turbo coding, transport blocks are segmented into byte aligned segments with a maximum information block size of 6144 bits. Error detection is supported by the use of 24 bit CRC. –Coexistence scenarios have been already done for the downlink and result can be found in TR

14 14 3GPP LTE presentation Physical Layer (Continued) –The generic frame structure is applicable to both FDD and TDD. Each radio frame is long and consists of 20 slots of length Tslot= x Ti = 0,5 ms, numbered from 0 to 19. A sub- frame is defined as two consecutive slots where sub-frame consists of slots and of 20 slots of length, numbered from 0 to 19. The structure of each half-frame in a radio frame is identical. A sub-frame is defined as two consecutive slots where sub-frame consists of slots 2i and 2i+1

15 15 3GPP LTE presentation Layer 2 and above over the radio interface –Overall architecture

16 16 3GPP LTE presentation Layer 2 and above over the radio interface –The eNode B hosts the following functions: Functions for Radio Resource Management: –Radio Bearer Control, –Radio Admission Control, –Connection Mobility Control, –Dynamic allocation of resources to UEs in both uplink and downlink (scheduling); IP header compression and encryption of user data stream; Selection of an MME at UE attachment;

17 17 3GPP LTE presentation Layer 2 and above over the radio interface : Layer 2 Structure at the eNode B

18 18 3GPP LTE presentation Layer 2 and above over the radio interface –For the UE two states are considered RRC_IDLE where: - UE specific DRX configured by NAS; -Broadcast of system information; -Paging; -Cell re-selection mobility; -The UE shall have been allocated an id which uniquely identifies the UE in a tracking area; –-No RRC context stored in the eNode B. RRC_CONNECTED where: -UE has an E-UTRAN-RRC connection; -UE has context in E-UTRAN; -E-UTRAN knows the cell which the UE belongs to; -Network can transmit and/or receive data to/from UE; -Network controlled mobility (handover); - Neighbour cell measurements; –-At PDCP/RLC/MAC level: –- UE can transmit and/or receive data to/from network; –- UE monitors control signalling channel for shared data channel to see if any transmission over the shared data channel has been allocated to the UE; –- UE also reports channel quality information and feedback information to eNode B; –-DRX/DTX period can be configured according to UE activity level for UE power saving and efficient resource utilization. This is under control of the eNode B

19 19 3GPP LTE presentation Interface towards the Core network –Generalities Two interfaces: –S1 for the Control plane –X1 for the User plane (new) Additional interface in between eNode Bs: X2 –Including both Control and User plane

20 20 3GPP LTE presentation Interface towards the Core network

21 21 3GPP LTE presentation Interface towards the Core network For the X1 interface Still under investigation S1 Interface Control Plane (eNB-MME)

22 22 3GPP LTE presentation eNode B X2 Interface –This interfaces allows inter-eNode B handover X2 Interface Control Plane

23 23 3GPP LTE presentation Conclusion Lot of progress made recently are not incorporated in this presentation based on material agreed at TSG RAN plenary in March However the timescale for completion of the specification is still foreseen to be in September 2007 All documentation referred to is available At :

24 24 3GPP LTE presentation Thanks for your attention

25 25 3GPP LTE presentation Annex Structure of the documentation for the physical layer specification


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