IT R&D Global Leader Radio Access Network Mobile Research Activites of ETRI Technology in 3GPP Evolution (Elementary Technologies of the Evolved RAN based on 3GPP LTE standards) June 29. 2007 송평중 -1-
Topics I. Overview II. Architecture Model for 3GE RAN III. Elementary Technologies of 3GE RAN System Information Delivery and Optimization Random Access Control Scheduling and Rate Control DRX Control Mobility Control Packet Loss Management IV. Test-bed Examples for 3GE RAN V. Concluding Remarks VI. Reference -2-
Overview Significantly increased peak data rates Increased cell edge bitrates Compatibility with other systems EUTRAN Target Improved spectrum efficiency Acceptable complexity, cost and pow er consump. Improved latency Reduced CAPEX and OPEX Scaleable bandwidth Packetoptimized Single Arch -3-
Overview 3G Evolution 시스템의특징 Vision : IMT-Advanced의 Basic Requirement 수용이가능한 Future-oriented radio access system! Technology : 무선기술의최적화와네트워크의단순화를통해 값싸고빠른대용량 시스템 Service : 융합서비스제공 (e.g. True quadruple play : IP voice, high-speed interactive (gaming), large data transfer (ftp) 및 mobile IP-TV) Standard : 2007 년말표준초안완성과 2010 년상용화목표 LTE/SAE (Long Term Evolution/System Architecture Evolution) EUTRAN/EPC (Evolved UTRAN for Access Network / Evolved Packet Core for Core Network) -4-
Architecture Model (System Architecture) 3GE 시스템구조 실시간패킷서비스제공에최적화된구조 (All_IP, ieee.802) 네트워크의단순화를통한시설비 / 운용비감소 (CAPEX & OPEX) 이종시스템간 Load Sharing & Network Sharing Single Architecture를이용한 Inter-RAT 3GPP 및 Non-3GPP 시스템과의공존및인터워킹 향후, LTE 중심의네트웍컨버젼스예상 E-NB : Evolved NodeB MME : Mobility Management Entity S-GW : Serving (SAE) Gateway P-GW : PDN (SAE) Gateway IP-BB : IP based BackBone PCRF : Policy based Charging Rule Fun GRRM : Global Radio Res. Management GTP-C : GTP for Control plane GTP-U : GTP for User plane CCS7 BSC BTS SGSN PSTN/ PSDN Appl. Service NW/ Control NW (IMS) S4 RNC NodeB HLR/HSS S3 P-GW S6 S1 (GTP-C) LTE-Uu (Radio Bearer) Public Internet SGi P-GW IP-BB (GTP-T) S-GW S11 MME IP Trans. NW E-NB -5- GERAN UTRAN UE EUTRAN (Multi- Mode) (S7) S1 (GTP-U) P-GW PCRF/ (GRRM) S2a/b ACR RAS Non-3GPP (e.g. WiMAX)
Architecture Model (System Interface) Radio interface (LTE-Uu) WCDMA 기본체제유지 서킷 / 패킷채널개념공존 (e.g DTCH/SCH) RACH 용도는 UL measurement report, Random Access Preamble (at L1) 전송 Move of PDCP down to the enodeb Network interface (S1/X2) Uplink channels.uplink Downlink channels Logical CHs 기존검증된 GTP 채택 GTP/SCTP 등은 패킷손실혹은순서 Transport CHs 교란을제어하기위한 IP 보강용도 Flexible interface with mesh-type Uu Interface Control Plane Layer 2 Functional Structure.. -6-
Elementary Technologies for 3GE RAN LTE = -7-
Elementary Technologies for 3GE RAN 3GE RAN 핵심요소기술 : LTE-Uu/X2/S1 연관기술의기능 & 성능최적화기술 (10) Basic Operation Mobility Operation Special & OM Operation Idle mode System Initialize, Cell (Re-)Selection, SIB, Idle Mobility HO preparation Measure, Neighbor Discovery & Target Selection embms Control Setup mode Random Access, Bearer Manage, SCH Scheduling, E2E QoS & RRM HO Execution Admission, PKT Loss Manage, Target Acquisition.. Network Sharing, Inter-Cell Interference Control, Load balancing.. Active mode Bearer Modify, DRX&DTX, ARQ & HARQ HO Completion Path switching, Route optimization, MIP registration NW Self Configuration & Optimization Release mode Release of Resources (IP addr, Bearer and Buffer...) Others (Home enodeb..) -8-
Initialization of RAN-1 (NW Self Configuration) i 기지국초기화절차란?. 기지국 (enodeb) 설치에서부터형상세팅과운용파라미터최적화까지의일련의절차 Self-configuration i 절차 기지국에전원넣고 RF 송신준비상태까지완성하기위한기지국형상의초기화과정 자동설치프로그램에의해시스템동작에필요한기본형상정보를세팅 Self-optimization 절차 단말 / 기지국의 ( 성능 ) 측정기능을이용하여네트웍을자동최적화하는절차 Optimization / Adaptation에해당 기지국초기화절차 SIB : System Information Broadcasting -9-
SIB Delivery and Optimization-2 기본개념 SIB 방송기술의최적화를통한 Cost per bit 최소화 SIB 정보의그룹핑, 방송주기, 프레임구성 (ffs) 기술등이중요 SIB 정보그룹핑 1 2 3 Static part (Primary-BCH on BCH, Common) : Scheduling_info, info SFN/BW/CP 등의 L1파라미터로구성되는극히제한된양의필수정보 (Fixed coding, 짧은방송주기 40ms, 1.25MHz 대역 ) Dedicated part (Dedicated-BCH on DL-SCH) Unicast mode로써 RRC 메시지와함께전송 (e.g. Handover) SIB 유형 System Info : Information for Cell/PLMN search (e.g. PLMN_ID) Access Info : Information needed prior to cell access (e.g. RACH) Mobility Info : Information valid across multiple cells, etc; SIB 방송주기와길이 P-BCH (40ms) 방송주기당 30~40 비트수준 GSM의경우 BCH는 2kbps Other SIBs (multi*40ms) : ffs SIB : System Information Broadcasting Dynamic part (Dynamic-BCH on DL-BCH, Cell-specific) : Primary- BCH를제외한대부분의시스템정보포함 -10-
Random Access Control-3 Random Access 절차 기본메커니즘은 WCDMA와유사하며, Triggering Event는 3가지! 1 Initial access from RRC_IDLE (Attach, Registration, Service Request, TA Update) 2 Handover access (Non-synch handover : e.g. Inter-RAT간비동기상태경우 ) 3 Data arrival during RRC_CONNECTED CONNECTED (UL 타이밍동기손실및 Scheduling Request 등 ) Random Access Procedure RA Triggers - Attach, - Registration, - Service req, -TA update - HO access -etc L1 전송 (Random Access Preamble) ACK 수신 (Random Access Response) DTX 수신 (Random Access Response 못받음 ) L3 전송 (RRC Connection Request) L1 재전송 (Random Access Preamble) 단말의 C-RNTI 사용방법 ( 랜덤액세스경우 ); RA에성공하였으나 C-RNTI를할당받지못하면, temp C-RNTI 버리고 new C-RNTI를받음 RA에성공하고 C-RNTI를기보유하면, old C-RNTI 재사용! RA : Random Access -11-
Random Access Control-3 Random Access 방식 Contention based (3 이벤트모두사용 ) Non-contention based (e.g. Handover access 경우 ) * Contention Resolution : 여러단말이 (3) 을동시에올린경우, 충돌 이발생한단말로피드백하는정보! Contention based RA (Normal Call) UE enb UE enb System Information (1) RACH Preamble on RACH (random_id (5bits), CQI (1, ffs) (2) RACH Response on DL_SCH (RA-RNTI, TA, UL_sched_grant, Ack ) TA 측정 L1/L2 Control Signaling (no HARQ) Non-contention based RA (HO call) MC MR RACH Preamble (0) HO Command HO 지시 절차 (non-contention RA preamble) (from S-Cell) (3) RRC Connection Request (init NAS message, temp C-RNTI) (4) RRC Contention Resolution* (temp C-RNTI) L3 Data (H-ARQ) RACH Preamble 절차 (3/4 생략 ) 충돌완화! (1) RACH Preamble (assigned RA preamble) (2) RACH Response (RA-RNTI, TA, UL_alloc) TA 측정 Ho 시도 (to T-Cell) (5) RRC Connection Setup (C-RNTI) (5) HO Confirm RRC Data -12-
Random Access Control-3 Non-synchronized random access Initial call attempts에서와같이비동기화된상황에서의랜덤액세스 상위계층에서 RA 수행에필요한정보제공 ; RACH scheduling info (Radio Frame 에서 RACH 채널이위치하는 Time/Sub-frame과 Frequency/Sub-carriers) Available preambles signature 및초기송출전력 Power-ramping step size (0dB 허용 ) Preamble 최대전송회수 랜덤액세스채널의재원 (3G에비해넉넉함 ) BW (BW RA ) : 1.25/(1.08) MHz (= 6 * RB) Access period (T RA ) : Multi * TTI 10ms에 Multi TTI 동안복수 RACH 을사용하여대형셀 / 대용량랜덤액세스를시도할수있으나, 통상 10ms 에한개 RACH 재원 (single TTI, 1.25MHz) 만을할당하여 64개단말이동시랜덤액세스하도록설계함 OLPC with power ramping CP Tcp (0.1ms) 1201 sub-carriers @20MHz RA preamble structure Preamble Sequence (6bits : 64 signatures) Tra (0.8ms) Random Access Channel 의재원 GP Tgp (0.1ms) Non-synchronized random access RA : Random Access OFDM sub-carrier spacing : 15KHz -13-
Scheduling & Rate Control-4 MAC 스케쥴러의동작원리 단말의서비스요청에따라기지국이무선자원을할당하는 Networkcontrolled scheduling 방식 LTE 무선공유채널 (UL/DL-SCH) 자원의효과적할당을위해 MAC 스케쥴러이용 MAC 스케쥴러의 Input은 Traffic volume, QoS, 전파환경및 UL MAC의버퍼상태등이며, Output 은 PRB & MCS ; PRB & MCS 는자원할당의기본단위로사용 (PRB는전파환경변화의최소단위, MCS는변조 / 코딩방식 ) PRB 소요량이한개 TTI 보다길면할당시간, 할당주기등의추가정보필요 Static 정보 ( 형상정보 ) 는 RRC, dynamic 정보 (TTI 별자원할당 ) 는 L1/L2 control 을이용하여단말에전달 Per UE grant 개념만허용 (No Per RB) Input -Tvol, QoS -Radio Env. Scheduler 의기본원리 DL-SCH physical-layer model Output -PRBs -MCS * PRB & MCS : Phy Resource Block & Modulation & Coding Scheme MAC Scheduler -14-
Scheduling & Rate Control-4 무선자원할당의 4 개유형 자원할당유형에따라 PRB 소요량과 MCS 방식을결정. 일례로 ; Long lived dynamic allocation: 임의의 TTI 만큼 PRB(s) 를할당하고, MCS 는동적제어. Long/Short (for PRB ) RRC/MAC (# of TTI) Dynamic/Fixed y (for MCS) 동적제어 / 고정제어 Ex : RACH Response Short-lived Dynamic PRB & MCS Allocation Types MAC Control. RRC Signalling 구분 L1/L2 Control (like dpcch) MAC PDU (like dpdch) RRC Message 제어형상 Short-lived (PRB) Dynamic (MCS) allocation e.g. RLC related control PDU Long-lived Fixed allocation EX) RACH Response. 16 bit_id (e.g. RA_RNTI) L1/L2 Control 구조 ( 예 ) 3 symbols 11 symbols L1/L2 Control MAC PDU (DL-SCH) TTI = 14 symbols (2 sub-frames) Control Payload (e.g. TF, UL_sched_grant, Ack in response to UL, ) -15-
Scheduling & Rate Control-4 How to minimize the signaling load to transfer the assigned UL/DL radio resources? RRC, MAC, L1/L2 control 등의시그널링부하를 Persistent/ Grouping, Sync, Blind detection 을통해최적화. 특히, 3GE 에서상당량의트래픽을차지할 VoIP scheduling 이핫이슈! 스케쥴링에서고려하는 2 가지요인 : HARQ 전송시점가변여부, MCS 적용여부 HSDPA 와유사메커니즘채택 Non-VoIP & VoIP Scheduling 방식 구분 DL/UL 제안방식비고 Non-VoIP Downlink Uplink Dynamic scheduling - Asynch-HARQ (C-RNTI, RB_alloc) Semi-dynamic (Grouping scheduling) - 오버헤드감소되나전력소모증대 Dynamic scheduling - Synch-HARQ (w/o C-RNTI, RB_alloc)(in enb) - Prioritized Bit Rate scheduling (in UE) : Starvation avoidance (e.g., weighted round robin) VoIP Downlink Persistent Async-adaptive scheduling - Async : HARQ 재전송시점가변 ( 기지국이스케쥴링 ) - Adaptive : 전파환경변화등의이유로 MCS 동적변경 * Synch-Non Adaptive이면오버헤드최소 ( 시점지정, MCS 고정 ) Uplink Persistent Sync-adaptive scheduling -16-
DRX Control-5 DRX 의기본개념 단말의밧테리절약기술의일종 기지국 / 단말의버퍼상태 ( 보낼데이터있는지 ) 를늘모니터하는기지국이 DRX/DTX 상태로의입 / 출제어를주관 DRX 인터벌이긴경우셀경계에머무는단말은무선링크실패확률이커지므로, DRX 측정인터벌은 UE mobility에따라가변필요 ( 단말이동속도, 단위시간당셀변경회수등 ) DRX interval and CQI reporting cycle Wake-up interval 동안단말은 CQI 및 Sounding reference signal (UL pilot) 을전송하고, UL 데이터전송에대한 HARQ ACK/NACK 및 Paging 등을수신할수있도록 ; 단말과기지국간타이밍조정. 이 interval 동안단말은 DRX 모드를중지해야함 DRX TTI value : Max 5.12초 /ffs (Short DRX cycle for VoIP : e.g.10 ms) DRX interval and CQI reporting cycle (UE) Wake-up interval (n * TTI) e.g. CQI cycle (k * TTI) DRX interval (m * TTI, m = 1, 2, 5,, 5120) TTI -17-
Packet Loss Management-6 Elementary Technologies for Mobility Control (Inter-System HO) 요소기술은 HO 3 단계에그룹핑됨 (HO Preparation//Execution// Completion) 세부내용은 IWCCF2007 자료참조 ( Seamless & Fast Vertical Handover in Heterogeneous Access Networks, May, 2007) Handover Preparation Handover Execution Handover Completion Actions Measurement(L1) &Triggering(L3) Admission Control & Target System Configuration Path Switching & Serving System Release, Neighbor System Discovery (opt) Security Check & QoS Negotiation Optimal Route Update to Target System Target System Selection Packet Loss Man agement, Target System Access MIP Triggering, CoA Acquisition & MIP Registration Outputs Selected target System Target System Accessed Service Resume via Target- System -18-
Packet Loss Management-6 How to minimize the packet loss and the handover interruption time? Requirement : At least, equal to that provided by CS domain handovers in GERAN! Solutions : Three possible data loss management at handover Bi-casting : 소스 / 타겟기지국에동시 Bi-casting ( 시점결정이어려워데이터유실 ) Do Nothing : LTE2G/3G 핸드오버중데이터유실 (2G/3G 의저속전송이원인 ) Data Forwarding : Buffering & forwarding ( 선호 ) Inter-RAT HO 기간중의방식비교 복잡하나실시간 QoS 보장함 (Data Forwarding, RT service) 단순하나실시간 QoS 보장안됨 (Do Nothing, NRT service with TCP) Attributes 패킷손실감소방안비교 Bi-casting (Nortel) Buffer forwarding (Alcatel) Do nothing (Motorola) Complexity Medium High Very low Lossless handovers Not possible Possible Not possible Handover No impact No impact No impact interruption time Backhaul High Medium Low 대역소요량 -19-
Packet Loss Management-6 (a) (b) U-plane interruption time during inter-enodeb handover UL= (a)+(b)+(c) (b) + (c), wheredlis(a)+(b) (b) U-Plane interruption estimates Comp. Cause [ms] Radio layer process UL RRC signalling - DL synch time, incl. BB & RF switching time - UL resource request & TA acquisition - UL resource granting - RRC msg encoding at the transmitter - RRC transmission on the radio interface - RRC processing time at the receiver 12 ± 2.5 6.5 UL U-plane active (a) Interruption due to radio L1/L2 layers U-plane active UE U-Plane interruption time in inter-enb handover Source enb Measurement report HO command DL synchronisation + Timing advance + UL resource request/grant (c) DL RRC Same as above 6.5 signalling (b) Interruption due to (d) Forwar- -Src enb processing 5 UL RRC signalling HO complete ding - Packet transmission (c) Interruption due to delay over the X2 interface DL RRC signalling Total UL interruption 25 time Total DL interruption 18.5 time * Estimated time Ack Data forwarding may continue even after path switch HO request HO request confirm...... Target enb MME/UPE Data forwarding (background process) U-plane route update (Path switch) Forwarded data only DL U-plane active U-plane active * Source : 3GPP (d) Interruption due to path switch -20-
Radio Resource Management-7 Definition of RRM RRM is to ensure the management of the radio resources over the air interface in such a way that maximum efficiency is gained prior to handover call setup as well as new call setup; to maximize the radio resource utilization to minimize the probability of access failure to the resource of ftarget tsystem Function of RRM 7 functions (see right side) RRM is tightly coupled with the operation of mobility management, especially for Inter-system mobility, An relationship model between RRM and mobility control -21-
Radio Resource Management-7 Load Balancing Mechanism by Handover Parameters Optimization Traffic high density Cell shrinking Neighbor list optimization Coverage and capacity control Problem : Increase of signaling load due to additional interactions Load is balanced between Cell A and Cell C Blocking rate as a function of mobile arrival rate (Copyright John Wiley & Sons Ltd * Source : 3GPP -22-
Edge-to-edge QoS-8 QoS 개념 (in LTE) 기존 QoS 개념을 LTE/SAE 전체대상으로확대하여 SAE Bearer Service (Service data flows) 에대한 E2E QoS 을정의 이를위해 QoS Label 개념을도입하고, LTE/SAE 시스템의전체영역에서구간별 QoS 매핑인덱스로활용 SAE Bearer Service Architecture QoS 와베어러서비스구조 Uu 구간 (MAC/RRM) : SAE QoS profile 에따라무선구간의 Data flow 전달 S1 구간 (diffsrv) : SAE QoS profile 에따라 S1 구간의 Data flow 전달 A sequence of service data flows in UL case; SDFs PFs Mapping (UE) PFs RB_ID Linking (UE) RB_ID S1 TE_ID Linking (enb) SAE Bearer Service Architecture UL Service Data Flows UL Packet Filter UL-PF RB-ID RB-ID S1-TE-ID Application / Service Layer RB_ID S5 TE_ID Linking (S-GW) Serving UE Radio Bearer enb DL Service Data Flows DL Packet Filter DL-PF S5/S8a-TE-ID S1-TE-ID S5/S8a-TE-ID S1 Bearer SAE-GW S5/S8 Bearer PDN SAE-GW -23-
Edge-to-edge QoS-8 QoS Profile QoS profile = <Label, GBR, MBR, ARP(FFS)> QOS Label = ( QoS profile ID ) QoS Label Bearer Type (GBR or Non-GBR) L2 Packet Delay Budget (Low or Medium or High) L2 Packet Loss QoS Label 특징분류 Name Bearer Type L2 Pkt Delay Budget L2 Pkt Loss Rate Example Services NG-1 NG-2 NG-3 Non- GBR Non- GBR Low (< 50 ms) Low (< 10^-6) Medium (< 100 ms) High (< 300 ms) High (< 10^-3) Low (< 10^-6) NRT :SIP/SDP RT :Gaming NRT :TCP interactive RT :Voice, Video (live) NRT :TCP bulk data RT :Video (playback) G-1 GBR Low (< 50 ms) Low (< 10^-6) RT :Gaming, NRT (ffs) G-2 GBR Medium (< 100 ms) High (< 10^-3) RT :Voice, Video (live) G-3 GBR High (< 300 ms) Low (< 10^-6) RT :Video (playback) Non- GBR -24-
embms Control-9 Definition of MB-SFN 효과적 MBMS 를위한 SFN 개념도입 An SFN area consists of a group of tightly synchronized cells where all cells are using the same radio resources in the same frequency band to synchronously transmit identical MBMS data Ap-to-m radio bearer is used to carry MBMS traffic (e.g. Mobile TV channel) MBMS functions enodeb MBMS 제어정보스케쥴링 MBMS 서비스전송 MBMS용 Radio bearer 제어 MCE (Multicast Coordination Entity ) MBMS 서비스분배 (MCE) 멀티셀환경하의 MBMS 전송코디 MBMS용 SAE bearer 제어 MBMS Architecture & Functional split MBSFN (Multicast/Broadcast Single-Frequency Networking) -25-
embms Control-9 MBMS Deployment Scenarios Transmission Carrier Radio Scenario Comments (SFN ) (Feq. layer) Bearer S-D Single-Cell Dedicatedcarrier -Single-cell (No SFN operation) p-t-m Specific-cell에서 only MBMS 단일전송 (SFN) (MBMS only). Soft combining & Synch tx 모두가능안함 1 -Dedicated-carrier (belong to Freq-layer) M-M Multi-Cell (No SFN) Mixed- Carrier (MBMS + 2 Voice/Data) p-t-m * RB (p-t-p) p) : not used MBMS p-t-m Transmission scenarions in E-UTRAN. MBMS 서비스만가능 (unicast data 전송은불가 ) Multi-cell에서 Unicast & MBMS 혼합전송 -Multi-cell (SFN operation). Soft combining & Synch tx 모두가능 - Mixed-carrier. MBMS/Unicast 모두가능 (EUTRAN은 MBMS, UTRA은 Unicast). Dual Receiver 필요 (Mobile TV & VoIP) Soft combinig at the cell boundary 2 1-26-
embms Control-9 Synchronization for MBMS multi-cell transmission MBMS 동기 : 단말이셀경계에서 soft combining 하여수신성능을개선하는효과있으며, 이를위해 3-layers 동기절차 를수행함 3-layers 동기절차 : SFN area내모든 enb가 (1) Radio Frame의시작점을맞추고 (L1 frame 동기 ) (2) MBMS contents 를동일시각에전송하여단말이 soft combining 을수행하도록제어하고 (L2 content 시각동기 ) (3) 각 TTI에서동일 PRB 패턴을사용하도록제어함. 이리되면각 enb는동일한자원블럭을동일 MBMS 서비스데이터에사용가능. Three layers synchronization for MBMS RF soft combining * BFN (enb frame num. counter) & AFN (agw frame number counter) 0 to 4095-27-
Home enodeb-11 Home enb scenario (New SI) WLAN 계열장비대체 (Home/Office/Campus 등의 Femto cell) Unlicensed or Licensed band (ffs) Handovers from LTE HNB to LTE (macro NodeB) shall be supported All cells belong to the same operator Users are roaming freely; users in HNB A can move to both the LTE macro cell, the other 3GPP system cell or directly to HNB B HIGHER NETWORK NODE C LTE MACRO CELL OTHER 3GPP SYSTEM A B -28-
Summary and Test-bed Examples for 3GE RAN -29-
Normal Call/Session Flows Originating Call Scenario for RT-service UE Power-On & Init PLMN/Cell Selection Uu 0. SYSTEM INFORMATION enodeb S1 MME/ SAE GW LTE Attach Procedure (Iden, Auth. and Registration to HSS) S5 Attach에서자원사전할당 (def IP addr, def DTCH) PCRF/ HSS Rando om Acces ss 1. RACH PREAMBLE (random_id, CQI..) < E-UTRAN 시그널링의특징 > 3. RACH RESPONSE (RA_RNTI, TA, ul_alloc..) Network-based control Attach 단계에서자원사전할당 (def IP address, def DTCH) 랜덤액세스충돌완화 (Contention Resolution) Re-auth Message Concatenation (signaling processing 신속 ) Call Setup time 대폭감소 (100ms이하, IP 패킷환경 ) 시그널링에대한 Security 강화 (RRC/MAC/NAS signaling) etc (14) MAC/RRM Tasks *8. Initial Context Setup Request* includes three type info ; (1) NAS PDU (2) UE Contexts (Security/QoS/Roaming_restrict/UE_capa ) restrict/ue capa (3) SAE Bearer Context (S-GW TEID, QoS Info) Context M (DCC Manage. for Signa H +.def DTCH) aling Bearer (d Manage. for Tra dedicated DTCH) affic 4. RRC CONNECTION REQUEST (NAS: Service Request) 5. RRC CONTETION RESOLUTION (starting time) 10. RRC CONNECTION SETUP (NAS: Service Accept, C-RNTI) 2. TA & RA-RNTI (5) Four Tasks - Admission Control(RRM), - Store UE-Context, - Reserve C-RNTI, -Configure enodeb 5. Four Tasks 7. INITIAL UE MESSAGE 9. Setup the UE context 8. INITIAL CONTEXT SETUP REQUEST* *8. Three type info included in this msg 11. RRC CONNECTION SETUP COMPLETE 12. INITIAL CONTEXT SETUP COMPLETE (enb S1 SC_ID, enb TEID..) Established default DTCH for Signaling (e.g, SIP) - QoS 매핑 ( 유 / 무선 ) & CAC - MAC sched (MCS, PRB) 15. RB SETUP (rb qos) Bearer QoS 할당 14. SAB SETUP REQUEST (BEARER qos) SAE bearer 설정 GTP Tunnel 13. PCC DECISION (QoS policy) 16. RB SETUP COMPLETE 17. SAB SETUP RESPONSE 18. PROVISION ACK (qos policy enforced) Activated dedicated DTCH for Packet Data Transfer GTP Tunnel -30-
Normal Handover Flows Inter-eNBeNB Handover Scenario < 핸드오버처리 3 단계 > HO Preparation (1-4) HO Execution (5-13) HO Completion (14-23) HO Pre paration HO Execution UE Uu MEASURE CONTROL F & M 1. MEASURE REPORT Source enodeb X2 2. HO Decision (Target enb) 3. HO REQUEST 6. DL data stopped & Buff, Integrity & ciphering of Mgs 7. HO COMMAND (new C-RNTI, starting time) 8. UL data stopped & Buff., UE Re-configuration (RF SW) Target enodeb S1 Packet Data via Source enodeb 4. Four Tasks 5. HO REQUEST ACK (new C-RNTI, Access Info, SIB, Tunnel_info..) 9. DL packet forwarding to target enb DL packet forwarding (i) via GTP Tunnel 10. DL data buffering 11. SYNCHRONIZATION (~RA Preamble) MME/ SA-GW (4) Four Tasks - Admission Control, - Store UE-Context, - Reserve New C-RNTI, -Configure enodeb 13. UL ALLOC + TA 12. UL TA measuring HO Comp letion 15. Resume UL data (21) - Flush DL buffer, - Continue to delivery In-transit DL data (i+1) 14. HO CONFIRM 17. HO COMPLETE 16. Resume DL data 18. Path switching 19. HO COMPLETE ACK 20. RELEASE RESOURCE 21. Two Tasks DL packet forwarding (i+1) 22. Release Resources 23. UE Update Location to MME Packet data via target enodeb -31-
An Example of LTE Testbed LTE Testbed (Ericsson, Jan/2007) 하단좌측 : LTE Testbed 는응용서버, 기지국 (RBS), 단말 (UE) 및 Host 로구성 싱글셀환경에서 L1, L2 중심의기본기능우선적개발 ( 멀티셀, 핸드오버는 2 단계에서개발 ) ATCA & AMC 프로세싱보드와 serial RapidIO 기술을활용한 Flexible & high-performance platform 개발 File Fe transfer, VoIP 및 Streaming Sreamng 등의복합서비스를동시발생하기위한독립서버 (Client) 와 SW 다운로딩과 디버깅을위해 Host (PC) 를사용 하단우측 : 기지국 (RBS) 과단말 (UE) 의기본구조는 RF 제외하곤유사하며모두 Application, SW, HW 분야로구성 ATCA 플랫폼은여러유형의인터페이스 (Serial RapidIO, Gigabit Ethernet) 를제공하고, Ext reference 에서 DSP AMC 등의 Processing element 간의타이밍분배, ATL 은 processor element 간 uniform 통신을제공 CPU, Overall Architecture of LTE Testbed Overall Function Model of enb (RBS) ATCA (Advanced Telecom Computing Architecture) Src : Ericsson Review No. 1, 2007-32-
Concluding Remarks 3GE RAN 기술은 2007 년말표준화완성과 2010 년상용화를목표로하는 Future-oriented radio access system! 기존무선기술의최적화와네트워크의 단순화를통해 값싸고 빠른대용량 시스템실현 펨토, 피코, 마이크로셀등으로의범위확장을위해 3GE RAN의지속적진화추진 IMT-Advanced 등의미래시스템으로의진화가용이 (All IP, Non-3GPP Mobility, Convergence, NW Sharing ) 도꼬모 / 에릭슨 / 노텔등 Test-bed 개발본격화 (2007 년-2008 년 ) 향후 RAN 기술의핫이슈전망 ; Reconfigurable & scalable arch, Self-configuring and self- optimizing, i i Seamless connectivity it @ Multi-operator/ t Multisystem, Neighbor system discovery & optimal system selection, Policy based RRM for adaptive E2E QoS, Cognitive radio based mobility control, etc -33-
Reference [1] 3GPP TS36.300, LTE Stage 2, 2007 [2] 3GPP TR_25813, Radio interface protocol aspects, 2006 [3] 3GPP TR_25814, Physical Layer Aspects for E-UTRA, 2006 [4] 3GPP, TR_25912 Feasibility study for EUTRA, 2006 [5] 3GPP TR_25913, Requirements for Evolved UTRA and UTRAN, 2006 [6] IST, E2R Project, Workshop Materials, 2005 [7] 3GPP LTE/SAE, SA2/RAN2/RAN3 Contributions, ti 2006-20072007 [8] Ericsson Review, LTE Test-bed, No. 1, 2007 [9] IWCCF2007, Seamless & Fast Vertical Handover in Heterogeneous Access Networks, May, 2007-34-
Q&A -35-