Wprowadzenie do techniki LTE Prowadzący: Szymon Raksimowicz Warszawa, maj 2014
Wprowadzenie do techniki LTE Szymon Raksimowicz
Agenda 1. Wprowadzenie 2. Architektura EPS 3. Interfejs radiowy 4. Stos protokołów 5. Identyfikatory 6. Stany w EPS 7. EPS bearer 8. Bezpieczeńatwo w EPS
Wprowadzenie 3GPP (ang. Third Generation Partnership Project) (Japonia) (Chiny) (Korea) (USA) (Europa) (Japonia)
Wprowadzenie 3GPP
Wprowadzenie
LTE=4G?
Wprowadzenie Założenia (3GPP TR 25.913) : DL 100 Mbit/s 300 Mbit/s UL 50 Mbit/s 75 Mbit/s pasmo do 20 MHz MIMO (ang. Multiple Input, Multiple Output) zmniejszenie opóźnień kompatybilność z systemami 3GPP i non-3gpp do 350 km/h 500 km/h
Wprowadzenie SAE (System Architecture Evolution) LTE (Long Term Evolution) EPS (Evolved Packet System) EPC (Evolved Packet Core) E-UTRAN (Evolved Universal Terrestrial Radio Access Network )
Architektura EPS
Architektura EPS UTRAN UE LTE-Uu GERAN S1-MME E-UTRAN S1-U SGSN S3 MME S11 S10 HSS S6a S4 Serving Gateway S12 S5 Gx PDN Gateway PCRF SGi Rx Operator's IP Services (e.g. IMS, PSS etc.) HSS - Home Subscriber Server PCRF - Policy and Charging Rules Function 3GPP TS 23.401
enodeb 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 when 3GPP TS 36.300
MME (Mobility Management Entity) NAS signalling and security; AS Security control; Inter CN node signalling for mobility between 3GPP access networks; Idle mode UE Reachability (including control and execution of paging retransmission); Tracking Area list management (for UE in idle and active mode); PDN GW and Serving GW selection; MME selection for handovers with MME change; SGSN selection for handovers to 2G or 3G 3GPP access networks; Authentication; Bearer management functions including dedicated bearer establishment; 3GPP TS 23.401
S-GW (Serving Gateway) The local Mobility Anchor point for inter-enb handover; Mobility anchoring for inter-3gpp mobility; E-UTRAN idle mode downlink packet buffering and initiation of network triggered service request procedure; Lawful Interception; Packet routeing and forwarding; Transport level packet marking in the uplink and the downlink; Accounting on user and QCI granularity for inter-operator charging; UL and DL charging per UE, PDN, and QCI. 3GPP TS 23.401
P-GW (PDN Gateway ) Per-user based packet filtering (by e.g. deep packet inspection); Lawful Interception; UE IP address allocation; Transport level packet marking in the uplink and the downlink; UL and DL service level charging, gating and rate enforcement; DL rate enforcement based on APN-AMBR; 3GPP TS 23.401
E-UTRAN i EPC
Interfejs radiowy UMTS/HSPA WCDMA (ang. Wideband Code Division Multiple Access) LTE OFDMA (DL) (ang. Orthogonal Frequency Division Multiple Access) SC-FDMA (UL) (ang. Single Carrier Frequency Division Multiple Access)
Zasoby radiowe One downlink slot Tslot DL Nsymb OFDM symbols k N N DL RB N DL symb RB sc N 1 Resource block RB sc resource elements 1 Slot = 0,5 ms, 7 OFDM symboli 12 podnośnych, 180 khz RB = 12*7 = 84 RE subcarriers subcarriers Resource element ( k, l) Resource Element (RE) QPSK 2 bity 16QAM 4 bity 64QAM 6 bitów DL l 0 l N symb 1 k 0 3GPP TS 36.211
Zasoby radiowe
Zasoby radiowe Pasmo [MHz] Liczba RB Liczba podnośnyc h Zajęte pasmo [MHz] Pasmo ochronne 1.4 6 72 1.08 2x0.16 MHz 3 15 180 2.7 2x0.15 MHz 5 25 300 4.5 2x0.25 MHz 10 50 600 9 2x0. 5 MHz 15 75 900 13.5 2x0.75 MHz 20 100 1200 18 2x1 MHz
Zasoby radiowe One slot, T slot = 15360T s = 0.5 ms One radio frame, T f = 307200T s = 10 ms #0 #1 #2 #3 #18 #19 One subframe 3GPP TS 36.211
Zasoby radiowe
Kanały w EPS PCCH Paging Control Channel BCCH - Broadcast control channel CCCH - Common control channel DCCH - Dedicated control channel DTCH - Dedicated traffic channel MCCH - Multicast control channel MTCH - Multicast traffic channel
Stos protokołów Control Plane NAS RRC PDCP RRC PDCP Relay S1-AP SCTP NAS S1-AP SCTP RLC RLC IP IP MAC MAC L2 L2 L1 L1 L1 L1 UE LTE-Uu enodeb S1-MME MME NAS Non access Stratum RRC - Radio Resource Control PDCP - Packet Data Convergence Protocol RLC- Radio Link Control MAC - Medium Access Control S1-AP S1 Application Protocol SCTP - Stream Control Transmission Protocol
Stos protokołów Control Plane GTP-C GTP-C GTP-C GTP-C UDP UDP UDP UDP IP IP IP IP L2 L2 L2 L2 L1 L1 L1 L1 MME S11 S-GW S - GW S5 or S8 P-GW Diameter Diameter SCTP SCTP IP IP L2 L1 L2 L1 GTP - GPRS tunnelling protocol MME S6a HSS
Stos protokołów User Plane Application IP IP PDCP PDCP Relay GTP-U GTP-U Relay GTP-U GTP-U RLC RLC UDP/IP UDP/IP UDP/IP UDP/IP MAC MAC L2 L2 L2 L2 L1 L1 L1 L1 L1 L1 UE LTE-Uu enodeb S1-U Serving GW S5/S8 a PDN GW SGi
Identyfikatory
Stany w EPS Detach, Attach Reject, TAU reject, E-UTRAN interface switched off due to Non-3GPP handover, All bearers deactivated EMM-DEREGISTERED EMM-REGISTERED Attach accept EMM state model in UE Detach, Attach Reject, TAU reject, All bearers deactivated EMM-DEREGISTERED EMM-REGISTERED Attach accept TAU accept for a UE selecting E-UTRAN from GERAN/UTRAN EMM state model in MME
Stany w EPS RRC connection released ECM-IDLE ECM-CONNECTED RRC connection established ECM state model in UE ECM-IDLE S1 connection released ECM-CONNECTED S1 connection established ECM state model in MME
EPS bearer
EPS bearer Application / Service Layer UL Traffic Flow Aggregates DL Traffic Flow Aggregates UL-TFT UL-TFT RB-ID RB-ID S1-TEID DL-TFT DL-TFT S5/S8-TEID S1-TEID S5/S8-TEID UE enodeb enb Serving GW PDN GW Radio Bearer S1 Bearer S5/S8 Bearer
EPS bearer SAE Bearer QoS QCI ARP Bearer Delay Loss GBR GBR MBR Non-GBR AMBR ARP Allocation and Retention Priority GBR Guaranteed Bit Rate MBR Maximum Bit Rate AMBR Aggregate Maximum Bit Rate
Charakterystka QCI QCI Resource Type Priority Packet Delay Budget Packet Error Loss Rate Example Services 1 2 100 ms 10-2 Conversational Voice 2 4 150 ms 10-3 Conversational Video (Live Streaming) GBR 3 3 50 ms 10-3 Real Time Gaming 4 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming) 5 1 100 ms 10-6 IMS Signalling 6 Video (Buffered Streaming) 6 300 ms 10-6 TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.) 7 Non-GBR Voice, 7 100 ms 10-3 Video (Live Streaming) Interactive Gaming 8 8 Video (Buffered Streaming) 300 ms 10-6 TCP-based (e.g., www, e-mail, chat, ftp, p2p file 9 9 sharing, progressive video, etc.) 3GPP TS 23.203
Bezpieczeństwo w EPS
Kategorie UE UE Category Maximum number of DL-SCH transport block bits received within a TTI (Note) Maximum number of bits of a DL-SCH transport block received within a TTI Total number of soft channel bits Category 1 10296 10296 250368 1 Category 2 51024 51024 1237248 2 Category 3 102048 75376 1237248 2 Category 4 150752 75376 1827072 2 Category 5 299552 149776 3667200 4 Category 6 301504 149776 (4 layers) 3654144 2 or 4 75376 (2 layers) Category 7 301504 149776 (4 layers) 3654144 2 or 4 75376 (2 layers) Category 8 2998560 299856 35982720 8 Maximum number of supported layers for spatial multiplexing in DL 3GPP TS 36.306
Kategorie UE UE Category Maximum number of UL-SCH transport block bits transmitted within a TTI Maximum number of bits of an UL- SCH transport block transmitted within a TTI Category 1 5160 5160 No Category 2 25456 25456 No Category 3 51024 51024 No Category 4 51024 51024 No Category 5 75376 75376 Yes Category 6 51024 51024 No Category 7 102048 51024 No Category 8 1497760 149776 Yes Support for 64QAM in UL 3GPP TS 36.306
LTE w praktyce Szerokość kanału radiowego Downlink Uplink 20 MHz 100 Mbit/s 48 Mbit/s 15 MHz 99 Mbit/s 35 Mbit/s 10 MHz 70 Mbit/s 23 Mbit/s 5 MHz 33 Mbit/s 10 Mbit/s
Częstotliwości pod LTE
Procedury (3GPP TS 23.401) Attach TAU UE triggered Service Request Network Triggered Service Request
Pytania?