EVERYTHING YOU EVER WANTED TO KNOW ABOUT LTE

Transcription

1 EVERYTHING YOU EVER WANTED TO KNOW ABOUT LTE (BUT WERE AFRAID TO ASK) SEMINAR PART 2/2 Jonathan Buschmann Ericsson Italy Rome, April 27, 2011

2 Objectives of the seminar Answer these questions How have mobile networks evolved over the years? What are the main performance targets for LTE/SAE? What is the new core architecture? How does mobility work in LTE? How are some key services supported? What is LTE physical layer like? How will 3G operators evolve their network? Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 2 (23)

3 History of Mobile Communications 1G FDMA (NMT, AMPS, TACS) 80 s - Voice (analog traffic, digital signaling) 2G TDMA (GSM, D-AMPS, PDC) and CDMA (IS-95) 90 s - Voice, SMS, CS data transfer ~ 9.6 kbit/s (50 kbit/s HSCSD) 2.5G TDMA (GPRS) 00 s - PS data transfer ~ 50 kbit/s 2.75G TDMA (GPRS+EDGE) 00 s - PS data ~ 150kbit/s 3-3.5G WCDMA (UMTS) and CDMA s - PS & CS data transfer ~ Mbit/s (HSPA/HSPA+), Voice, SMS 3.9G OFDMA (LTE/SAE) 10 s - PS Data and Voice (VoIP) ~ 100Mbit/s 4G IMT Advanced Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 3 (23)

4 LTE/SAE Main Targets WCDMA comparison (Release 6) DL 100 Mbps 20 MHz) DL = 14.4 Mbps (5 MHz) Peak Data Rate UL 50 Mbps (@ 20 MHz) UL = 5.8 Mbps (5 MHz) Peak Spectral Efficiency DL 5 bps/hz UL 2.5 bps/hz DL = 2.9 bps/hz UL = 1.2 bps/hz Spectrum Flexibility 1.4; 3; 5; 10 ;15; 20 MHz 5 MHz (single layer) User Plane Latency < 10 ms (two way latency) 50 ms Packet Network >60 VoIP calls / MHz Mobility Speeds up to 350 km/h Coverage Cell radius up to 30 km Interworking with existing 2G/3G radio access networks CS & PS layers 40 voice calls / MHz Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 4 (23)

5 Architecture Evolution Towards a simpler architecture WCDMA LTE/SAE GGSN CN SGSN RNC A flat architecture for optimized performance and cost efficiency SAE CN (EPC) P/S-GW RNC Moving RNC functions to e-nodeb NodeB NodeB e-nodeb e-nodeb UE UE Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 5 (23)

6 EPS Architecture EPS (Evolved Packet System) EPC (Evolved Packet Core) MME/S-GW MME/S-GW SAE (System Architecture Evolution) S1 E-UTRAN X2 enb X2 X2 enb LTE (Long Term Evolution) Uu enb UE Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 6 (23)

7 LTE/SAE USER & CONTROL PLANES USER Plane UE enb Serving GW PDN GW Peer Entity APPLICATION APPLICATION IP PACKET IP S1-AP IP S1-AP IP PDCP PDCP GTP-U GTP-U GTP-U GTP-U SCTP RLC RLC UDP/IP UDP/IP UDP/IP UDP/IP MAC MAC L2 L2 L2 L2 L2 PHY PHY L1 L1 L1 L1 L1 Uu S1-UP S5/S8 CONTROL Plane UE NAS enb MME NAS RRC RRC S1-AP S1-AP PDCP PDCP SCTP SCTP RLC RLC IP IP MAC MAC L2 L2 PHY PHY L1 L1 Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 7 (23) Uu S1-CP

8 EPC & E-UTRAN Detailed Architecture Mobility Management Entity Idle mode mobility management EPS Bearer Management (QoS) Security AAA (both data and signalling) UE attach/detach Serving Gateway Packet routing & forwarding Mobility anchor Collecting information for charging Buffering U-plane packets while paging SAE Evolved Packet Core MME MME S10 S5/S8 S11 P-GW S-GW Gi Internet PDN Gateway UE IP Address Allocation QoS Enforcement Packet filtering (QoS) Lawful Interception Charging (Service) Non-3GPP Mobilty Anchor Not seen by terminal S1-CP S1-UP enodeb LTE E-UTRAN X2-CP X2-UP Radio Resource Management Radio Physical layer Encryption of UP & CP Measurement ctrl & reporting Mobility Control enodeb enodeb Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 8 (23) UE

9 Implementation of SAE/LTE Integration with 2G/3G SAE Gi Internet SGSN/ MME S4/S11 P-GW S5/S8 S-GW Gb GRAN BSC Abis UTRAN 3G RNC Iub Iu-CP S4-UP Iu-UP S1-CP X2-CP X2-UP S1-UP LTE enodeb enodeb BTS Node B UE Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 9 (23)

10 User Equipment States MME Tracking Area (TA) enodeb MME Handover UE ON OFF ON UE (active) (idle) OFF enb UE position known on Cell level in enb TA update Signalling Connection release REGISTERED (UE attached) IDLE UE-MME connection released No data transfer UE stands by for paging Signalling Connection re-activation CONNECTED UE-MME connection Data transfer possible ATTACH! DETACH! DEREGISTERED (UE not attached) DETACHED No UE-MME connection UE not known by MME DETACH! Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 10 (23)

11 Intra-LTE Handover with no MME relocation Internet P-GW Gi S1 IV MME/ S-GW I VI VII I II III IV V VI VII VIII HANDOVER REQUEST HANDOVER REQUEST ACK HANDOVER COMMAND PACKET FORWARDING HANDOVER CONFIRM PATH SWITCH REQUEST PATH SWITCH ACK RELEASE RESOURCE Source e-nb II III X2 VIII V Target e-nb Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 11 (23)

12 Handower in LTE (Inter-pool example) IP PoP Internet 1 2 Gi P-GW Gi S-GW S-GW S-GW S-GW(1) S5 S-GW(2) S-GW S-GW MME MME MME S10 MME MME MME IP/Ethernet transport IP/Ethernet transport Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 12 (23)

13 EPS services IP Multimedia Subsystem SIP IP Multimedia Subsystem (IMS) IMS is an all-ip network for multimedia services 3GPP standard SIP main protocol from IETF IMS is access independent The only 3GPP standardized means to support voice 3GPP One-Voice profile promotes IMS Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 13 (23)

14 EPS services Multimedia Broadcast Multicast Service Application: Mobile TV Broadcast/Multicast Services Point-To-Multipoint transmission in downlink - saves network resources New entities Broadcast Multicast Service Center (BM-SC) in the IP network MBMS Gateway in the EPC Network MCE (Multicell Coordination Entity) in the E-UTRAN (may be integrated in the E-NB) BM-SC E-UTRAN Content Provider enb enb MBMS Gateway MCE Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 14 (23) EPC

15 LTE PHYSICAL LAYER Multiple Access TECHNIQUES OFDMA TDMA CDMA Frequency Division Multiple Access Time Division Multiple Access Code Division Multiple Access Orthogonal Frequency Division Multiple Access frequency Each User has a unique frequency (1 voice channel per user). All users transmit at the same time time Each User has a unique time slot Several users share the same frequency. frequency Each User has a unique scrambling code Many users share the same frequency and time time frequency Each User and has a unique Time and Frequency Resource Many users are separated in frequency and/or time 1G (i.e.tacs) 2G (i.e. GSM) 3G (i.e. WCDMA) 4G (i.e. LTE) Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 15 (23)

16 LTE PHYSICAL LAYER MAIN ASPECTS Downlink: Adaptive OFDM Channel-dependent scheduling and link adaptation Uplink: SC-FDMA with dynamic bandwidth Low PAPR Higher power efficiency Reduced uplink interference Multi-Antennas, both RBS and terminal Interference rejection High bit rates Coverage Flexible bandwidth FDD, TDD & Half Duplex TDD f DL TX f UL FDD-only f DL f UL time time f=15khz RX frequency frequency MHz Half-duplex FDD TDD-only f DL/UL 1 ms 180 khz Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 16 (23)

17 LTE PHYSICAL LAYER MULTI ANTENNA TECHNIQUEs Advanced Antenna Communications Tx & Rx Diversity Multi-Layer Transmission (Spatial Multiplexing) MIMO 2x2 channel capacity x ~ 2 TX MIMO 4x4 channel capacity x ~ 4 Beam-Forming TX Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 17 (23)

18 LTE PHYSICAL LAYER MULTI ANTENNA TECHNIQUES Example of Spatial Multiplexing Layer 2 Layer 2 Layer 1 e-nb UE Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 18 (23)

19 LTE PHYSICAL LAYER RF Spectrum flexibility Bandwidth flexibility LTE physical-layer specification supports any bandwidth in the range 6 RBs to 100 RBs in steps of one RB 6 RB ( 1.1 MHz) 100 RB ( 20 MHz) Radio requirements only specified for a limited set of bandwidths MHz Radio requirements only specified for a limited set of bandwidths Relatively straighforward to extend to additional bandwidths All UEs must support the maximum bandwidth of each supported band Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 19 (23)

20 LTE Devices Category DL peak rate UL peak rate Max DL mod 64QAM Max UL mod 16QAM 64QAM Layers for spatial mux All UEs support 4 Tx antennas at enodeb Soft buffer sizes under discussion MBMS is a separate capability FDD, HD-FDD and TDD are independent capabilities Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 20 (23)

21 Simple deployment & Management Automated Neighbor Relations (ANR) OSS-RC X2 Cell A Ncell list; -CGI 17 -CGI 22 UE Cell B PCI = 5 CGI =19 Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 21 (23)

22 Simple deployment & Management Node selection DNS used for node selection EPS uses S-NAPTR (RFC 3958) to map services and protocols (i.e. interfaces) to CNAMEs Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 22 (23)

23 What frequencies for LTE? First deployments in Europe in 2.6 GHz band (Sweden and Norway) Most appetizing band is the Digital Dividend 800 MHz Re-farming of UMTS and GSM bands also will happen Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 23 (23)

24 What frequencies for LTE? In italy Re-farming for 900 MHz already agreed: TI, VFE, WIND: 10 MHz Extra 5 MHz destined to H3G AGCOM just announced preliminary rules and public consultation for auction for 800, 1800, 2000 and 2600 Single auction for all spectrum 1800 spectrum liberated by DoD and GSM (25 MHz FDD) 2000 (UMTS TDD band left from IPSE) 2600 (70 MHz) 800 (digital dividend) Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 24 (23)

25 Mobile Broad Band State of the Art & Evolution I ub ATM I ub IP MSC SAE System Architecture Evolution WCDMA HSPA/HSPA+ up to 14/42 Mbps PDH Node B ETH ATM SDH ETH SDH MGW P/S-GW SGSN/MME EPC Fibre/MW CS core RNC SGSN GGSN RNC PS core Microwave WCDMA OFDMA/SC-FDMA up to nx100 Mbps w MIMO (n=2, 3) Node B I ub ATM PDH e-node B LTE Long Term Evolution S 1 /X 2 Copper AccessIP TRANSFORMATION Metro Core Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 25 (23) IP ETH I ub ATM xdsl IP Network LTE/SAE HSPA EVOLUTION Transformation

26 references SAE and the Evolved Packet Core (Academic Press) Magnus Olsson, Shabnam Sultana, Stefan Rommer, Lars Frid, Catherine Mulligan 3G Evolution: HSPA and LTE for Mobile Broadband (Academic Press) Erik Dahlman, Stefan Parkvall, Johan Skold, Per Beming 4G LTE/LTE-Advanced for Mobile Broadband (Academic Press) Erik Dahlman, Stefan Parkvall, Johan Skold Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 26 (23)

27 Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 27 (23)

28 Acronyms ATM CS Core e-node B DNS EPC EPS E-UTRAN HSPA IMS LTE OFDM OFDMA MBMS MIMO PS Core SAE Asynchronous Transfer Mode Circuit Switched Core Evolved Node B (refers to LTE Access Network) Domain Name System Evolved Packet Core Evolved Packet System Evolved UMTS Radio Access Network High Speed Packet Access (UMTS Broadband Technology) IP Multimedia Systems Long Term Evolution (refers to radio interface and network functionalities evolution in RAN) Orthogonal Frequency Division Multiplexing Orthogonal Frequency Division Multiple Access Multimedia Broadcast Multicast Service Multiple Input Multiple Output (multiple port antenna systems both at Node B and User Equipment) Packed Switched Core System Architecture Evolution (refers to Core network evolution) Everything You Ever Wanted to Know About LTE Public Ericsson AB Page 28 (23)