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  • 1. UMTS Long Term Evolution (LTE) technology intro + evolution measurement aspects Reiner Stuhlfauth Reiner.Stuhlfauth@rohde-schwarz.com Training Centre Rohde & Schwarz, Germany Subject to change – Data without tolerance limits is not binding. R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarks of the owners.  2011 ROHDE & SCHWARZ GmbH & Co. KG Test & Measurement Division - Training Center ROHDE & SCHWARZ GmbH reserves the copy right to all of any part of these course notes. Permission to produce, publish or copy sections or pages of these notes or to translate them must first be obtained in writing from ROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany
  • 2. Technology evolution path 2005/2006 GSM/ GPRS 2009/2010 2007/2008 2011/2012 EDGE, 200 kHz EDGEevo VAMOS DL: 473 kbps UL: 473 kbps DL: 1.9 Mbps UL: 947 kbps 2013/2014 Double Speech Capacity UMTS HSDPA, 5 MHz HSPA+, R7 HSPA+, R8 HSPA+, R9 HSPA+, R10 DL: 2.0 Mbps UL: 2.0 Mbps DL: 14.4 Mbps UL: 2.0 Mbps DL: 28.0 Mbps UL: 11.5 Mbps DL: 42.0 Mbps UL: 11.5 Mbps DL: 84 Mbps UL: 23 Mbps DL: 84 Mbps UL: 23 Mbps HSPA, 5 MHz DL: 14.4 Mbps UL: 5.76 Mbps LTE (4x4), R8+R9, 20MHz cdma 2000 1xEV-DO, Rev. 0 1.25 MHz 1xEV-DO, Rev. A 1.25 MHz DL: 3.1 Mbps UL: 1.8 Mbps DL: 1 Gbps (low mobility) UL: 500 Mbps 1xEV-DO, Rev. B 5.0 MHz DL: 2.4 Mbps UL: 153 kbps LTE-Advanced R10 DL: 300 Mbps UL: 75 Mbps DL: 14.7 Mbps UL: 4.9 Mbps DO-Advanced DL: 32 Mbps and beyond UL: 12.4 Mbps and beyond Fixed WiMAX scalable bandwidth Mobile WiMAX, 802.16e Up to 20 MHz Advanced Mobile WiMAX, 802.16m 1.25 … 28 MHz typical up to 15 Mbps DL: 75 Mbps (2x2) UL: 28 Mbps (1x2) DL: up to 1 Gbps (low mobility) UL: up to 100 Mbps November 2012 | LTE Introduction | 2
  • 3. Why LTE? Ensuring Long Term Competitiveness of UMTS l LTE is the next UMTS evolution step after HSPA and HSPA+. l LTE is also referred to as EUTRA(N) = Evolved UMTS Terrestrial Radio Access (Network). l Main targets of LTE: l Peak data rates of 100 Mbps (downlink) and 50 Mbps (uplink) l Scaleable bandwidths up to 20 MHz l Reduced latency l Cost efficiency l Operation in paired (FDD) and unpaired (TDD) spectrum November 2012 | LTE Introduction | 3
  • 4. Peak data rates and real average throughput (UL) 100 58 11,5 Data rate in Mbps 10 15 5,76 5 2 2 1,8 2 0,947 1 0,473 0,7 0,5 0,174 0,153 0,2 0,1 0,1 0,1 0,1 0,03 0,01 GPRS (Rel. 97) EDGE (Rel. 4) 1xRTT WCDMA (Rel. 99/4) E-EDGE (Rel. 7) 1xEV-DO Rev. 0 1xEV-DO Rev. A HSPA (Rel. 5/6) HSPA+ (Rel. 7) LTE 2x2 (Rel. 8) Technology max. peak UL data rate [Mbps] November 2012 | LTE Introduction | max. avg. UL throughput [Mbps] 4
  • 5. Comparison of network latency by technology 800 158 160 710 700 2G / 2.5G latency 600 120 500 100 85 400 80 70 320 300 60 46 190 200 3G / 3.5G / 3.9G latency 140 40 100 20 30 0 0 GPRS (Rel. 97) EDGE (Rel. 4) WCDMA (Rel. 99/4) HSDPA (Rel. 5) HSUPA (Rel. 6) E-EDGE (Rel. 7) HSPA+ (Rel. 7) LTE (Rel. 8) Technology Total UE Air interface Node B November 2012 | LTE Introduction | Iub 5 RNC Iu + core Internet
  • 6. Round Trip Time, RTT •ACK/NACK generation in RNC TTI ~10msec MSC Iu Iub/Iur Serving RNC Node B SGSN TTI =1msec MME/SAE Gateway eNode B •ACK/NACK generation in node B November 2012 | LTE Introduction | 6
  • 7. Major technical challenges in LTE New radio transmission schemes (OFDMA / SC-FDMA) FDD and TDD mode MIMO multiple antenna schemes Throughput / data rate requirements Timing requirements (1 ms transm.time interval) Multi-RAT requirements (GSM/EDGE, UMTS, CDMA) Scheduling (shared channels, HARQ, adaptive modulation) System Architecture Evolution (SAE) November 2012 | LTE Introduction | 7
  • 8. Introduction to UMTS LTE: Key parameters Frequency Range Channel bandwidth, 1 Resource Block=180 kHz UMTS FDD bands and UMTS TDD bands 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz 6 Resource Blocks 15 Resource Blocks 25 Resource Blocks 50 Resource Blocks 75 Resource Blocks 100 Resource Blocks Modulation Schemes Downlink: QPSK, 16QAM, 64QAM Uplink: QPSK, 16QAM, 64QAM (optional for handset) Multiple Access Downlink: OFDMA (Orthogonal Frequency Division Multiple Access) Uplink: SC-FDMA (Single Carrier Frequency Division Multiple Access) MIMO technology Downlink: Wide choice of MIMO configuration options for transmit diversity, spatial multiplexing, and cyclic delay diversity (max. 4 antennas at base station and handset) Uplink: Multi user collaborative MIMO Peak Data Rate Downlink: 150 Mbps (UE category 4, 2x2 MIMO, 20 MHz) 300 Mbps (UE category 5, 4x4 MIMO, 20 MHz) Uplink: 75 Mbps (20 MHz) November 2012 | LTE Introduction | 8
  • 9. LTE/LTE-A Frequency Bands (FDD) E-UTRA Operating Band Uplink (UL) operating band BS receive UE transmit Downlink (DL) operating band BS transmit UE receive FUL_low – FUL_high FDL_low – FDL_high Duplex Mode 1 1920 MHz – 1980 MHz 2110 MHz – 2170 MHz FDD 2 1850 MHz – 1910 MHz 1930 MHz – 1990 MHz FDD 3 1710 MHz – 1785 MHz 1805 MHz – 1880 MHz FDD 4 1710 MHz – 1755 MHz 2110 MHz – 2155 MHz FDD 5 824 MHz – 849 MHz 869 MHz – 894MHz FDD 6 830 MHz – 840 MHz 875 MHz – 885 MHz FDD 7 2500 MHz – 2570 MHz 2620 MHz – 2690 MHz FDD 8 880 MHz – 915 MHz 925 MHz – 960 MHz FDD 9 1749.9 MHz – 1784.9 MHz 1844.9 MHz – 1879.9 MHz FDD 10 1710 MHz – 1770 MHz 2110 MHz – 2170 MHz FDD 11 1427.9 MHz – 1452.9 MHz 1475.9 MHz – 1500.9 MHz FDD 12 698 MHz – 716 MHz 728 MHz – 746 MHz FDD 13 777 MHz – 787 MHz 746 MHz – 756 MHz FDD 14 788 MHz – 798 MHz 758 MHz – 768 MHz FDD 17 704 MHz – 716 MHz 734 MHz – 746 MHz FDD 18 815 MHz – 830 MHz 860 MHz – 875 MHz FDD 19 830 MHz – 845 MHz 875 MHz – 890 MHz FDD 20 832 MHz - 862 MHz 791 MHz - 821 MHz FDD 21 1447.9 MHz - 1462.9 MHz 1495.9 MHz - 1510.9 MHz FDD 22 3410 MHz - 3500 MHz 3510 MHz - 3600 MHz FDD November 2012 | LTE Introduction | 9
  • 10. LTE/LTE-A Frequency Bands (TDD) E-UTRA Operating Band Uplink (UL) operating band BS receive UE transmit Downlink (DL) operating band BS transmit UE receive FUL_low – FUL_high FDL_low – FDL_high Duplex Mode 33 1900 MHz – 1920 MHz 1900 MHz – 1920 MHz TDD 34 2010 MHz – 2025 MHz 2010 MHz – 2025 MHz TDD 35 1850 MHz – 1910 MHz 1850 MHz – 1910 MHz TDD 36 1930 MHz – 1990 MHz 1930 MHz – 1990 MHz TDD 37 1910 MHz – 1930 MHz 1910 MHz – 1930 MHz TDD 38 2570 MHz – 2620 MHz 2570 MHz – 2620 MHz TDD 39 1880 MHz – 1920 MHz 1880 MHz – 1920 MHz TDD 40 2300 MHz – 2400 MHz 2300 MHz – 2400 MHz TDD 41 3400 MHz – 3600MHz 3400 MHz – 3600MHz November 2012 | LTE Introduction | TDD 10
  • 11. Orthogonal Frequency Division Multiple Access l OFDM is the modulation scheme for LTE in downlink and uplink (as reference) l Some technical explanation about our physical base: radio link aspects November 2012 | LTE Introduction | 11
  • 12. What does it mean to use the radio channel? Using the radio channel means to deal with aspects like: C A D B Transmitter Receiver MPP Time variant channel Frequency selectivity Doppler effect attenuation November 2012 | LTE Introduction | 12
  • 13. Still the same “mobile” radio problem: Time variant multipath propagation A: free space A: free space B: reflection B: reflection C: diffraction C: diffraction D: scattering D: scattering C A D B Transmitter Multipath Propagation and Doppler shift Receiver reflection: object is large compared to wavelength scattering: object is small or its surface irregular November 2012 | LTE Introduction | 13
  • 14. Multipath channel impulse response The CIR consists of L resolvable propagation paths L 1 h  , t    ai  t  e i 0 path attenuation ji  t      i  path phase path delay |h|²  delay spread November 2012 | LTE Introduction | 14
  • 15. Radio Channel – different aspects to discuss Bandwidth or Wideband Symbol duration Channel estimation: Pilot mapping t Short symbol duration Frequency? Narrowband or t Long symbol duration Time? frequency distance of pilots? Repetition rate of pilots? November 2012 | LTE Introduction | 15
  • 16. Frequency selectivity - Coherence Bandwidth power Here: substitute with single Scalar factor = 1-tap Frequency selectivity How to combat channel influence? f Narrowband = equalizer Can be 1 - tap Wideband = equalizer Must be frequency selective Here: find Math. Equation for this curve November 2012 | LTE Introduction | 16
  • 17. Time-Invariant Channel: Scenario Fixed Scatterer ISI: Inter Symbol Interference: Happens, when Delay spread > Symbol time Successive symbols will interfere Fixed Receiver Transmitter Channel Impulse Response, CIR Transmitter Signal Receiver Signal collision t t Delay Delay spread →time dispersive November 2012 | LTE Introduction | 17
  • 18. Motivation: Single Carrier versus Multi Carrier |H(f)| f TSC Source: Kammeyer; Nachrichtenübertragung; 3. Auflage B B 1 TSC t |h(t)| t l Time Domain l Delay spread > Symboltime TSC → Inter-Symbol-Interference (ISI) → equalization effort l Frequency Domain l Coherence Bandwidth Bc < Systembandwidth B → Frequency Selective Fading → equalization effort November 2012 | LTE Introduction | 18
  • 19. Motivation: Single Carrier versus Multi Carrier |H(f)| f TSC Source: Kammeyer; Nachrichtenübertragung; 3. Auflage B B 1 TSC t |h(t)| t f |H(f)| f  B t TMC  N  TSC November 2012 | LTE Introduction | B 1  N TMC 19
  • 20. What is OFDM? Single carrier transmission, e.g. WCDMA Broadband, e.g. 5MHz for WCDMA Orthogonal Frequency Division Multiplex Several 100 subcarriers, with x kHz spacing November 2012 | LTE Introduction | 20
  • 21. Idea: Wide/Narrow band conversion H(ƒ) h(τ) … S/P … … ƒ t / Tb h(τ) t / Ts „Channel Memory“ τ τ One high rate signal: Frequency selective fading N low rate signals: Frequency flat fading November 2012 | LTE Introduction | 21
  • 22. OFDM signal generation e.g. QPSK 00 11 10 10 01 01 11 01 …. h*(sinjwt + cosjwt) h*(sinjwt + cosjwt) => Σ h * (sin.. + cos…) Frequency time OFDM symbol duration Δt 2012 | November LTE Introduction | 22
  • 23. Mapper COFDM X + Σ Mapper ..... Data with FEC overhead X X X + November 2012 | LTE Introduction | 23 OFDM symbol
  • 24. Fourier Transform, Discrete FT Fourier Transform  H ( f )   h(t )e 2 j ft dt ;   h(t )  H ( f )e  2  j ft df ;  Discrete Fourier Transform (DFT) N 1 H n   hk e 2 j k n / N k 0 1 hk  N N 1 H e n 0 n  2 j k N 1 N 1 n n   hk cos(2  k )  j  hk sin(2  k ); N N k 0 k 0 n N ; November 2012 | LTE Introduction | 24
  • 25. OFDM Implementation with FFT (Fast Fourier Transformation) Transmitter Channel d(0) Map . . . Map P/S b (k ) S/P d(1) IDFT NFFT Map s(n) d(FFT-1) h(n) Receiver d(0) Demap . . . Demap n(n) S/P d(1) DFT NFFT ˆ k b( ) P/S Demap r(n) d(FFT-1) November 2012 | LTE Introduction | 25
  • 26. Inter-Carrier-Interference (ICI) 10 SMC  f  0 -10 -30 S xx  -20 -40 -50 -60 -70 -1 f-2 f-1 f0 f1 f2 -0.5 0   0.5 1 f Problem of MC - FDM ICI Overlapp of neighbouring subcarriers → Inter Carrier Interference (ICI). Solution “Special” transmit gs(t) and receive filter gr(t) and frequencies fk allows orthogonal subcarrier → Orthogonal Frequency Division Multiplex (OFDM) November 2012 | LTE Introduction | 26
  • 27. Rectangular Pulse A(f) Convolution sin(x)/x t f Δt Δf frequency time November 2012 | LTE Introduction | 27
  • 28. Orthogonality Orthogonality condition: Δf = 1/Δt Δf November 2012 | LTE Introduction | 28
  • 29. ISI and ICI due to channel Symbol l l-1  l+1 h  n Receiver DFT Window n Delay spread fade out (ISI) fade in (ISI) November 2012 | LTE Introduction | 29
  • 30. ISI and ICI: Guard Intervall Symbol l l-1  l+1 h  n TG  Delay Spread Receiver DFT Window n Delay spread Guard Intervall guarantees the supression of ISI! November 2012 | LTE Introduction | 30
  • 31. Guard Intervall as Cyclic Prefix Cyclic Prefix Symbol l l-1  l+1 h  n TG  Delay Spread Receiver DFT Window n Delay spread Cyclic Prefix guarantees the supression of ISI and ICI! November 2012 | LTE Introduction | 31
  • 32. Synchronisation Cyclic Prefix OFDM Symbol : l  1 CP l 1 l CP CP CP Metric Search window ~ n November 2012 | LTE Introduction | 32
  • 33. DL CP-OFDM signal generation chain l Data source OFDM signal generation is based on Inverse Fast Fourier Transform (IFFT) operation on transmitter side: QAM Modulator 1:N N symbol streams IFFT Frequency Domain OFDM symbols Time Domain l On receiver side, an FFT operation will be used. November 2012 | LTE Introduction | 33 N:1 Useful OFDM symbols Cyclic prefix insertion
  • 34. OFDM: Pros and Cons Pros:  scalable data rate  efficient use of the available bandwidth  robust against fading  1-tap equalization in frequency domain Cons:  high crest factor or PAPR. Peak to average power ratio  very sensitive to phase noise, frequency- and clock-offset  guard intervals necessary (ISI, ICI) → reduced data rate November 2012 | LTE Introduction | 34
  • 35. MIMO = Multiple Input Multiple Output Antennas November 2012 | LTE Introduction | 35
  • 36. MIMO is defined by the number of Rx / Tx Antennas and not by the Mode which is supported 1 SISO 1 Mode Typical todays wireless Communication System Single Input Single Output 1 MISO 1 Multiple Input Single Output M 1 1 SIMO Single Input Multiple Output M 1 1 MIMO M M Multiple Input Multiple Output Definition is seen from Channel Multiple In = Multiple Transmit Antennas November 2012 | LTE Introduction | Transmit Diversity l Maximum Ratio Combining (MRC) l Matrix A also known as STC l Space Time / Frequency Coding (STC / SFC) Receive Diversity l Maximum Ratio Combining (MRC) Receive / Transmit Diversity Spatial Multiplexing (SM) also known as: l Space Division Multiplex (SDM) l True MIMO l Single User MIMO (SU-MIMO) l Matrix B Space Division Multiple Access (SDMA) also known as: l Multi User MIMO (MU MIMO) l Virtual MIMO l Collaborative MIMO Beamforming 36
  • 37. MIMO modes in LTE -Tx diversity -Beamforming -Rx diversity Better S/N -Spatial Multiplexing -Multi-User MIMO Increased Throughput per UE Increased Throughput at Node B November 2012 | LTE Introduction | 37
  • 38. RX Diversity Maximum Ratio Combining depends on different fading of the two received signals. In other words decorrelated fading channels November 2012 | LTE Introduction | 38
  • 39. TX Diversity: Space Time Coding Fading on the air interface data space *  s2  *  s1  time  s1 S2    s2 Alamouti Coding The same signal is transmitted at differnet antennas Aim: increase of S/N ratio  increase of throughput Alamouti Coding = diversity gain approaches RX diversity gain with MRRC! -> benefit for mobile communications November 2012 | LTE Introduction | 39
  • 40. MIMO Spatial Multiplexing C=B*T*ld(1+S/N) SISO: Single Input Single Output Higher capacity without additional spectrum! S MIMO: C   T  B  ld (1  ) ? N Multiple Input Multiple Output min( N T , N R ) i i i 1 i Increasing capacity per cell November 2012 | LTE Introduction | 40
  • 41. The MIMO promise l Channel capacity grows linearly with antennas  Max Capacity ~ min(NTX, NRX) l l Assumptions  l l Perfect channel knowledge Spatially uncorrelated fading Reality  l Imperfect channel knowledge l Correlation ≠ 0 and rather unknown November 2012 | LTE Introduction | 41
  • 42. Spatial Multiplexing Coding Fading on the air interface data data Throughput: <200% 200% 100% Spatial Multiplexing: We increase the throughput but we also increase the interference! November 2012 | LTE Introduction | 42
  • 43. Introduction – Channel Model II Correlation of propagation pathes h11 h21 s1 r1 hMR1 h12 s2 h22 Transmitter NTx antennas hMR2 h1MT sNTx s estimates r2 Receiver h2MT hMRMT rNRx H NRx antennas r Rank indicator Capacity ~ min(NTX, NRX) → max. possible rank! But effective rank depends on channel, i.e. the correlation situation of H November 2012 | LTE Introduction | 43
  • 44. Spatial Multiplexing prerequisites Decorrelation is achieved by: difficult l Decorrelated data content on each spatial stream l Large antenna spacing l Environment with a lot of scatters near the antenna (e.g. MS or indoor operation, but not BS) Channel condition Technical assist l Precoding l Cyclic Delay Diversity But, also possible that decorrelation is not given November 2012 | LTE Introduction | 44
  • 45. MIMO: channel interference + precoding MIMO channel models: different ways to combat against channel impact: I.: Receiver cancels impact of channel II.: Precoding by using codebook. Transmitter assists receiver in cancellation of channel impact III.: Precoding at transmitter side to cancel channel impact November 2012 | LTE Introduction | 45
  • 46. MIMO: Principle of linear equalizing R = S*H + n Transmitter will send reference signals or pilot sequence to enable receiver to estimate H. n ^ r r s Tx H-1 Rx H LE The receiver multiplies the signal r with the Hermetian conjugate complex of the transmitting function to eliminate the channel influence. November 2012 | LTE Introduction | 46
  • 47. Linear equalization – compute power increase h11 H = h11 SISO: Equalizer has to estimate 1 channel h11 h12 H= h21 h11 h12 h21 h22 h22 2x2 MIMO: Equalizer has to estimate 4 channels November 2012 | LTE Introduction | 47
  • 48. transmission – reception model noise s A transmitter •Modulation, •Power •„precoding“, •etc. H + R receiver channel •detection, •estimation •Eliminating channel impact •etc. Linear equalization at receiver is not very efficient, i.e. noise can not be cancelled November 2012 | LTE Introduction | r 48
  • 49. MIMO – work shift to transmitter Transmitter Channel November 2012 | LTE Introduction | Receiver 49
  • 50. MIMO Precoding in LTE (DL) Spatial multiplexing – Code book for precoding Code book for 2 Tx: Codebook index Number of layers  1 0 1 2 3 4 5 2 1  0    0  1    1 1 0   2 0 1  1 1 1    2 1 1 1 1  2 1 Additional multiplication of the layer symbols with codebook entry 1 1 1    2  j  j 1 1   2 1 1 1    2  j 1 1   2  j  - - - November 2012 | LTE Introduction | 50
  • 51. MIMO precoding Ant1 Ant2 precoding t +  2 1 1 ∑ t + 1 -1 1 precoding ∑=0 t t November 2012 | LTE Introduction | 51
  • 52. MIMO – codebook based precoding Precoding codebook noise s A transmitter H + R receiver channel Precoding Matrix Identifier, PMI Codebook based precoding creates some kind of „beamforming light“ November 2012 | LTE Introduction | 52 r
  • 53. MIMO: avoid inter-channel interference – future outlook e.g. linear precoding: Y=H*F*S+V V1,k S + Link adaptation Transmitter F H Space time receiver + xk yk VM,k Feedback about H Idea: F adapts transmitted signal to current channel conditions November 2012 | LTE Introduction | 53
  • 54. MAS: „Dirty Paper“ Coding – future outlook l Multiple Antenna Signal Processing: „Known Interference“ l Is like NO interference l Analogy to writing on „dirty paper“ by changing ink color accordingly „Known „Known Interference Interference is No is No Interference“ Interference“ „Known Interference is No Interference“ November 2012 | LTE Introduction | 54 „Known Interference is No Interference“
  • 55. Spatial Multiplexing Codeword Fading on the air interface data Codeword data Spatial Multiplexing: We like to distinguish the 2 useful Propagation passes: How to do that? => one idea is SVD November 2012 | LTE Introduction | 55
  • 56. Idea of Singular Value Decomposition s1 MIMO r1 know r=Hs+n s2 r2 channel H Singular Value Decomposition wanted ~ ~ ~ r=Ds+n ~ s1 SISO ~ s2 ~ r2 channel D November 2012 | LTE Introduction | ~ r1 56
  • 57. Singular Value Decomposition (SVD) r=Hs+n H = U Σ (V*)T U = [u1,...,un] eigenvectors of (H*)T H V = [v1,...,vm] eigenvectors of H (H*)T  1 0 0 0  0 2    0 0 3  0   0   0  i eigenvalues of (H*)T H singular values  i  i ~ = (U*)T r r ~ s = (V*)T s ~ = (U*)T n n ~= Σ s + n ~ ~ r November 2012 | LTE Introduction | 57
  • 58. MIMO: Signal processing considerations MIMO transmission can be expressed as r = Hs+n which is, using SVD = UΣVHs+n n1 σ1 s1 V s2 U Σ VH n2 σ2 r1 UH r2 Imagine we do the following: 1.) Precoding at the transmitter: Instead of transmitting s, the transmitter sends s = V*s 2.) Signal processing at the receiver Multiply the received signal with UH, r = r*UH So after signal processing the whole signal can be expressed as: r =UH*(UΣVHVs+n)=UHU Σ VHVs+UHn = Σs+UHn =InTnT =InTnT November 2012 | LTE Introduction | 58
  • 59. MIMO: limited channel feedback H Transmitter s1 s2 Receiver n1 σ1 V U Σ VH σ2 n2 UH r1 r2 Idea 1: Rx sends feedback about full H to Tx. -> but too complex, -> big overhead -> sensitive to noise and quantization effects Idea 2: Tx does not need to know full H, only unitary matrix V -> define a set of unitary matrices (codebook) and find one matrix in the codebook that maximizes the capacity for the current channel H -> these unitary matrices from the codebook approximate the singular vector structure of the channel => Limited feedback is almost as good as ideal channel knowledge feedback November 2012 | LTE Introduction | 59
  • 60. Cyclic Delay Diversity, CDD A2 Amp litud e A1 D Transmitter B Delay Spread Time Delay Multipath propagation precoding +  + precoding No multipath propagation November 2012 | LTE Introduction | 60 Time Delay
  • 61. „Open loop“ und „closed loop“ MIMO Open loop (No channel knowledge at transmitter) r  Hs  n Channel Status, CSI Rank indicator Closed loop (With channel knowledge at transmitter r  HWs  n Channel Status, CSI Adaptive Precoding matrix („Pre-equalisation“) Feedback from receiver needed (closed loop) November 2012 | LTE Introduction | 61 Rank indicator
  • 62. MIMO transmission modes Transmission mode1 SISO Transmission mode4 Closed-loop spatial multiplexing Transmission mode2 TX diversity Transmission mode3 Open-loop spatial multiplexing 7 transmission modes are defined Transmission mode5 Multi-User MIMO Transmission mode7 SISO, port 5 = beamforming in TDD Transmission mode6 Closed-loop spatial multiplexing, using 1 layer Transmission mode is given by higher layer IE: AntennaInfo November 2012 | LTE Introduction | 62
  • 63. Beamforming Closed loop precoded beamforming Adaptive Beamforming •Classic way •Kind of MISO with channel •Antenna weights to adjust beam knowledge at transmitter •Directional characteristics •Specific antenna array geometrie •Dedicated pilots required •Precoding based on feedback •No specific antenna array geometrie •Common pilots are sufficient November 2012 | LTE Introduction | 63
  • 64. Spatial multiplexing vs beamforming Spatial multiplexing increases throughput, but looses coverage November 2012 | LTE Introduction | 64
  • 65. Spatial multiplexing vs beamforming Beamforming increases coverage November 2012 | LTE Introduction | 65
  • 66. Basic OFDM parameter LTE f  15 kHz  1 T Fs  N FFT  f Fs  f NFFT N FFT  3.84Mcps 256  2048 Coded symbol rate= R S/P N TX Sub-carrier Mapping IFFT Data symbols Size-NFFT November 2012 | LTE Introduction | 66 CP insertion
  • 67. LTE Downlink: Downlink slot and (sub)frame structure Symbol time, or number of symbols per time slot is not fixed One radio frame, Tf = 307200Ts=10 ms One slot, Tslot = 15360Ts = 0.5 ms #0 #1 #2 #3 #18 #19 One subframe We talk about 1 slot, but the minimum resource is 1 subframe = 2 slots !!!!! Ts  1 15000  2048 November 2012 | LTE Introduction | 67 Ts = 32.522 ns
  • 68. Resource block definition 1 slot = 0,5msec 12 subcarriers Resource block =6 or 7 symbols In 12 subcarriers Resource element UL DL N symb or N symb 6 or 7, Depending on cyclic prefix November 2012 | LTE Introduction | 68
  • 69. LTE Downlink OFDMA time-frequency multiplexing QPSK, 16QAM or 64QAM modulation 1 resource block = 180 kHz = 12 subcarriers frequency UE4 UE5 UE3 UE2 UE6 Subcarrier spacing = 15 kHz UE1 *TTI = transmission time interval ** For normal cyclic prefix duration 1 subframe = 1 slot = 0.5 ms = 1 ms= 1 TTI*= 7 OFDM symbols** 1 resource block pair November 2012 | LTE Introduction | 69 time
  • 70. LTE: new physical channels for data and control Physical Control Format Indicator Channel PCFICH: Indicates Format of PDCCH Physical Downlink Control Channel PDCCH: Downlink and uplink scheduling decisions Physical Downlink Shared Channel PDSCH: Downlink data Physical Hybrid ARQ Indicator Channel PHICH: ACK/NACK for uplink packets Physical Uplink Shared Channel PUSCH: Uplink data Physical Uplink Control Channel PUCCH: ACK/NACK for downlink packets, scheduling requests, channel quality info November 2012 | LTE Introduction | 70
  • 71. LTE Downlink: FDD channel mapping example Subcarrier #0 November 2012 | LTE Introduction | RB 71
  • 72. LTE Downlink: baseband signal generation code words Scrambling layers Modulation Mapper OFDM Mapper Avoid constant sequences For MIMO Weighting Split into data Several streams for streams if MIMO needed November 2012 | LTE Introduction | OFDM signal generation Precoding Modulation Mapper QPSK 16 QAM 64 QAM OFDM signal generation OFDM Mapper Layer Mapper Scrambling antenna ports 72 1 OFDM symbol per stream 1 stream = several subcarriers, based on Physical ressource blocks
  • 73. Adaptive modulation and coding Transportation block size User data FEC Flexible ratio between data and FEC = adaptive coding November 2012 | LTE Introduction | 73
  • 74. Channel Coding Performance November 2012 | LTE Introduction | 74
  • 75. Automatic repeat request, latency aspects •Transport block size = amount of data bits (excluding redundancy!) •TTI, Transmit Time Interval = time duration for transmitting 1 transport block Transport block Round Trip Time ACK/NACK Network UE Immediate acknowledged or non-acknowledged feedback of data transmission November 2012 | LTE Introduction | 75
  • 76. HARQ principle: Multitasking Δt = Round trip time Tx Data Data Data Data Data Data Data Data Data ACK/NACK Rx process Demodulate, decode, descramble, FFT operation, check CRC, etc. ACK/NACK Processing time for receiver Rx process Demodulate, decode, descramble, FFT operation, check CRC, etc. t Described as 1 HARQ process November 2012 | LTE Introduction | 76 Data
  • 77. LTE Round Trip Time RTT n+4 n+4 UL Data t=0 t=1 t=2 t=3 t=4 Downlink HARQ Data PDCCH PHICH ACK/NACK n+4 Uplink t=5 t=6 t=7 t=8 t=9 t=0 t=1 t=2 t=3 t=4 t=5 1 frame = 10 subframes 8 HARQ processes RTT = 8 msec November 2012 | LTE Introduction | 77
  • 78. HARQ principle: Soft combining 1st transmission with puncturing scheme P1 l T i is a e am l o h n e co i g 2nd transmission with puncturing scheme P2 l hi i n x m le f cha n l c ing Soft Combining = Σ of transmission 1 and 2 l Thi is an exam le of channel co ing Final decoding lThis is an example of channel coding November 2012 | LTE Introduction | 78
  • 79. Hybrid ARQ Chase Combining = identical retransmission Turbo Encoder output (36 bits) Systematic Bits Parity 1 Parity 2 Transmitted Bit Rate Matching to 16 bits (Puncturing) Original Transmission Retransmission Systematic Bits Parity 1 Parity 2 Punctured Bit Chase Combining at receiver Systematic Bits Parity 1 Parity 2 November 2012 | LTE Introduction | 79
  • 80. Hybrid ARQ Incremental Redundancy Turbo Encoder output (36 bits) Systematic Bits Parity 1 Parity 2 Rate Matching to 16 bits (Puncturing) Original Transmission Retransmission Systematic Bits Parity 1 Parity 2 Punctured Bit Incremental Redundancy Combining at receiver Systematic Bits Parity 1 Parity 2 November 2012 | LTE Introduction | 80
  • 81. LTE Physical Layer: SC-FDMA in uplink Single Carrier Frequency Division Multiple Access November 2012 | LTE Introduction | 81
  • 82. LTE Uplink: How to generate an SC-FDMA signal in theory? Coded symbol rate= R DFT Sub-carrier Mapping IFFT CP insertion NTX symbols Size-NTX Size-NFFT  LTE provides QPSK,16QAM, and 64QAM as uplink modulation schemes  DFT is first applied to block of NTX modulated data symbols to transform them into frequency domain  Sub-carrier mapping allows flexible allocation of signal to available sub-carriers  IFFT and cyclic prefix (CP) insertion as in OFDM  Each subcarrier carries a portion of superposed DFT spread data symbols  Can also be seen as “pre-coded OFDM” or “DFT-spread OFDM” November 2012 | LTE Introduction | 82
  • 83. LTE Uplink: How does the SC-FDMA signal look like?  In principle similar to OFDMA, BUT:  In OFDMA, each sub-carrier only carries information related to one specific symbol  In SC-FDMA, each sub-carrier contains information of ALL transmitted symbols November 2012 | LTE Introduction | 83
  • 84. LTE uplink SC-FDMA time-frequency multiplexing 1 resource block = 180 kHz = 12 subcarriers Subcarrier spacing = 15 kHz frequency UE1 UE2 UE3 1 slot = 0.5 ms = 7 SC-FDMA symbols** 1 subframe = 1 ms= 1 TTI* UE4 UE5 UE6 *TTI = transmission time interval ** For normal cyclic prefix duration time November 2012 | LTE Introduction | QPSK, 16QAM or 64QAM modulation 84
  • 85. LTE Uplink: baseband signal generation UE specific Scrambling code Scrambling Avoid constant sequences Modulation mapper QPSK 16 QAM 64 QAM (optional) Transform precoder Discrete Fourier Transform November 2012 | LTE Introduction | Resource element mapper Mapping on physical Ressource, i.e. subcarriers not used for reference signals 85 SC-FDMA signal gen. 1 stream = several subcarriers, based on Physical ressource blocks
  • 86. LTE evolution LTE Rel. 9 features LTE Advanced November 2012 | LTE Introduction | 86
  • 87. The LTE evolution Rel-9 eICIC enhancements Relaying Rel-10 In-device co-existence Diverse Data Application CoMP Rel-11 Relaying eICIC eMBMS enhancements Carrier Aggregation SON enhancements MIMO 8x8 Positioning MIMO 4x4 Public Warning System Home eNodeB Self Organizing Networks eMBMS DL Dual Layer Beamforming Enhanced SC-FDMA UL DL UL Multi carrier / Multi-RAT Base Stations LTE Release 8 FDD / TDD November 2012 | LTE Introduction | 87
  • 88. What are antenna ports? l 3GPP TS 36.211(Downlink) “An antenna port is defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed.” l What does that mean? l The UE shall demodulate a received signal – which is transmitted over a certain antenna port – based on the channel estimation performed on the reference signals belonging to this (same) antenna port. November 2012 | LTE Introduction | 88
  • 89. What are antenna ports? l Consequences of the definition l There is one sort of reference signal per antenna port l Whenever a new sort of reference signal is introduced by 3GPP (e.g. PRS), a new antenna port needs to be defined (e.g. Antenna Port 6) l 3GPP defines the following antenna port / reference signal combinations for downlink transmission: l l l l l l l Port 0-3: Cell-specific Reference Signals (CS-RS) Port 4: MBSFN-RS Port 5: UE-specific Reference Signals (DM-RS): single layer (TX mode 7) Port 6: Positioning Reference Signals (PRS) Port 7-8: UE-specific Reference Signals (DM-RS): dual layer (TX mode 8) Port 7-14: UE specific Referene Signals for Rel. 10 Port 15 – 22: CSI specific reference signals, channel status info in Rel. 10 November 2012 | LTE Introduction | 89
  • 90. What are antenna ports? l Mapping „Antenna Port“ to „Physical Antennas“ Antenna Port 1 AP0 AP1 AP2 AP3 AP4 AP5 AP6 AP7 AP8 Physical Antennas 1 1 1 PA0 W5,0 PA1 W5,1 W5,2 PA2 W5,3 … PA3 … … … The way the "logical" antenna ports are mapped to the "physical" TX antennas lies completely in the responsibility of the base station. There's no need for the base station to tell the UE. November 2012 | LTE Introduction | 90
  • 91. LTE antenna port definition Antenna ports are linked to the reference signals -> one example: Normal CP Cell Specific RS PA -RS PCFICH /PHICH /PDCCH PUSCH or No Transmission UE in idle mode, scans for Antenna port 0, cell specific RS November 2012 | LTE Introduction | UE in connected mode, scans Positioning RS on antenna port 6 to locate its position 91
  • 92. Multimedia Broadcast Messaging Services, MBMS Broadcast: Public info for everybody Unicast: Private info for dedicated user Multicast: Common info for User after authentication November 2012 | LTE Introduction | 92
  • 93. LTE MBMS architecture November 2012 | LTE Introduction | 93
  • 94. MBMS in LTE MBMS GW | MME MBMS GW: MBMS Gateway MCE: Multi-Cell/Multicast Coordination Entity M3 | M1 M1: user plane interface M2: E-UTRAN internal control plane interface M3: control plane interface between E-UTRAN and EPC MCE M2 | eNB Logical architecture for MBMS November 2012 | LTE Introduction | 94
  • 95. MBSFN – MBMS Single Frequency Network Mobile communication network each eNode B sends individual signals November 2012 | LTE Introduction | Single Frequency Network each eNode B sends identical signals 95
  • 96. MBSFN If network is synchronised, Signals in downlink can be combined November 2012 | LTE Introduction | 96
  • 97. evolved Multimedia Broadcast Multicast Services Multimedia Broadcast Single Frequency Network (MBSFN) area l l Useful if a significant number of users want to consume the same data content at the same time in the same area! Same content is transmitted in a specific area is known as MBSFN area. l l Each MBSFN area has an own identity (mbsfn-AreaId 0…255) and can consists of multiple cells; a cell can belong to more than one MBSFN area. MBSFN areas do not change dynamically over time. MBSFN area 255 MBSFN area 0 11 3 MBSFN reserved cell. A cell within the MBSFN area, that does not support MBMS transmission. 1 13 8 4 2 14 9 13 7 5 15 12 6 10 MBSFN area 1 A cell can belong to more than one MBSFN area; in total up to 8. November 2012 | LTE Introduction | 97
  • 98. eMBMS Downlink Channels l Downlink channels related to MBMS l l l l MCCH MTCH MCH PMCH Multicast Control Channel Multicast Traffic Channel Multicast Channel Physical Multicast Channel l MCH is transmitted over MBSFN in specific subrames on physical layer l MCH is a downlink only channel (no HARQ, no RLC repetitions) l l Higher Layer Forward Error Correction (see TS26.346) Different services (MTCHs and MCCH) can be multiplexed November 2012 | LTE Introduction | 98
  • 99. eMBMS channel mapping Subframes 0,4,5 and 9 are not MBMS, because Of paging occasion can occur here Subframes 0 and 5 are not MBMS, because of PBCH and Sync Channels November 2012 | LTE Introduction | 99
  • 100. eMBMS allocation based on SIB2 information 011010 Reminder: Subframes 0,4,5, and 9 Are non-MBMS November 2012 | LTE Introduction | 100
  • 101. eMBMS: MCCH position according to SIB13 November 2012 | LTE Introduction | 101
  • 102. LTE Release 9 Dual-layer beamforming l 3GPP Rel-8 – Transmission Mode 7 = beamforming without UE feedback, using UE-specific reference signal pattern, l l l l Estimate the position of the UE (Direction of Arrival, DoA), Pre-code digital baseband to direct beam at direction of arrival, BUT single-layer beamforming, only one codeword (TB), 3GPP Rel-9 – Transmission Mode 8 = beamforming with or without UE feedback (PMI/RI) using UE-specific reference signal pattern, but dual-layer, l l l l Mandatory for TDD, optional for FDD, 2 (new) reference signal pattern for two new antenna ports 7 and 8, New DCI format 2B to schedule transmission mode 8, Performance test in 3GPP TS 36.521 Part 1 (Rel-9) are adopted to support testing of transmission mode 8. November 2012 | LTE Introduction | 102
  • 103. LTE Release 9 Dual-layer beamforming – Reference Symbol Details l Cell specific antenna port 0 and antenna port 1 reference symbols Antenna Port 0 l Antenna Port 1 Antenna Port 7 Antenna Port 8 UE specific antenna port 7 and antenna port 8 reference symbols November 2012 | LTE Introduction | 103
  • 104. 2 layer beamforming throughput Spatial multiplexing: increase throughput but less coverage 1 layer beamforming: increase coverage SISO: coverage and throughput, no increase 2 layer beamforming Increases throughput and coverage coverage Spatial multiplexing increases throughput, but looses coverage November 2012 | LTE Introduction | 104
  • 105. Location based services l Location Based Services“ l Products and services which need location information l Future Trend: Augmented Reality November 2012 | LTE Introduction | 105
  • 106. Where is Waldo? November 2012 | LTE Introduction | 106
  • 107. Location based services The idea is not new, … so what to discuss? Satellite based services Location controller Network based services Who will do the measurements? The UE or the network? = „assisted“ Who will do the calculation? The UE or the network? = „based“ So what is new? Several ideas are defined and hybrid mode is possible as well, Various methods can be combined. November 2012 | LTE Introduction | 107
  • 108. E-UTRA supported positioning methods November 2012 | LTE Introduction | 108
  • 109. E-UTRA supported positioning network architecture Control plane and user plane signaling LCS4) Client SUPL / LPP Serving Gateway (S-GW) S1-U LPPa LPP S1-MME LTE-capable device User Equipment, UE (LCS Target) S5 Packet Gateway (P-GW) Mobile Management Entity (MME) Lup SLP1) LCS Server (LS) SLs E-SMLC2) SLs GMLC3) LTE base station eNodeB (eNB) Location positioning protocol LPP = control plane signaling Secure User Plane SUPL= user plane signaling November 2012 | LTE Introduction | SLP – SUPL Location Platform, SUPL – Secure User Plane Location E-SMLC – Evolved Serving Mobile Location Center 3) GMLC – Gateway Mobile Location Center 4) LCS – Location Service 5) 3GPP TS 36.455 LTE Positioning Protocol Annex (LPPa) 6) 3GPP TS 36.355 LTE Positioning Protocol (LPP) 1) 2) 109
  • 110. E-UTRAN UE Positioning Architecture l l In contrast to GERAN and UTRAN, the E-UTRAN positioning capabilities are intended to be forward compatible to other access types (e.g. WLAN) and other positioning methods (e.g. RAT uplink measurements). Supports user plane solutions, e.g. OMA SUPL 2.0 UE = User Equipment SUPL* = Secure User Plane Location OMA* = Open Mobile Alliance SET = SUPL enabled terminal SLP = SUPL locaiton platform E-SMLC = Evolved Serving Mobile Location Center MME = Mobility Management Entity RAT = Radio Access Technology *www.openmobilealliance.org/technical/release_program/supl_v2_0.aspx November 2012 | LTE Introduction | 110 Source: 3GPP TS 36.305
  • 111. Global Navigation Satellite Systems l GNSS – Global Navigation Satellite Systems; autonomous systems: l GNSS are designed for l GPS – USA 1995. continuous l GLONASS – Russia, 2012. reception, outdoors. l Gallileo – Europe, target 201?. Compass (Beidou) – China, under development, target 2015. IRNSS – India, planning process. l l l Challenging environments: urban, indoors, changing locations. E1 E5a L5 L5b 1164 L2 1215 G2 1237 L1 E6 1260 1300 1559 1591 1563 GALLILEO GPS G1 1587 f [MHz] 1610 GLONASS Signal fCarrier [MHz] Signal fCarrier [MHz] Signal fCarrier [MHz] E1 1575,420 L1C/A 1575,420 G1 1602±k*0,562 5 E6 1278,750 L1C 1575,420 G2 1246±k*0,562 5 E5 1191,795 L2C 1227,600 E5a 1176,450 L5 1176,450 E5b 1207,140 k = -7 … 13 http://www.hindawi.com/journals/ijno/2010/812945/ November 2012 | LTE Introduction | 111
  • 112. LTE Positioning Protocol (LPP) 3GPP TS 36.355 LPP position methods - A-GNSS Assisted Global Navigation Satellite System - E-CID Enhanced Cell ID - OTDOA Observed time differerence of arrival LTE radio signal *GNSS and LTE radio signals eNB Measurements based on reference sources* Target Device Location Server LPP Assistance data UE SUPL enabled Terminal LPP over RRC Control plane solution E-SMLC SET LPP over SUPL User plane solution SLP November 2012 | LTE Introduction | 112 Enhanced Serving Mobile Location Center SUPL location platform
  • 113. GNSS positioning methods supported l Autonomeous GNSS l Assisted GNSS (A-GNSS) l The network assists the UE GNSS receiver to improve the performance in several aspects: – Reduce UE GNSS start-up and acquisition times – Increase UE GNSS sensitivity – Allow UE to consume less handset power l UE Assisted – UE transmits GNSS measurement results to E-SMLC where the position calculation takes place l UE Based – UE performs GNSS measurements and position calculation, suppported by data … – … assisting the measurements, e.g. with reference time, visible satellite list etc. – … providing means for position calculation, e.g. reference position, satellite ephemeris, etc. November 2012 | LTE Introduction | 113 Source: 3GPP TS 36.305
  • 114. GNSS band allocations E1 E5a L5 E5b L2 1164 1215 G2 1237 E6 1260 L1 1300 November 2012 | LTE Introduction | 1559 1563 114 1587 1591 G1 1610 f/MHz
  • 115. GPS and GLONASS satellite orbits GPS: 26 Satellites Orbital radius 26560 km GLONASS: 26 Satellites Orbital radius 25510 km November 2012 | LTE Introduction | 115
  • 116. Why is GNSS not sufficent? Critical scenario Very critical scenario GPS Satellites visibility (Urban) l Global navigation satellite systems (GNSSs) have restricted performance in certain environments l Often less than four satellites visible: critical situation for GNSS positioning  support required (Assisted GNSS)  alternative required (Mobile radio positioning) Reference [DLR] November 2012 | LTE Introduction | 116
  • 117. (A-)GNSS vs. mobile radio positioning methods (A-)GNSS Mobile radio systems Low bandwidth (1-2 MHz) High bandwidth (up to 20 MHz for LTE) Very weak received signals Comparatively strong received signals Similar received power levels from all satellites One strong signal from the serving BS, strong interference situation Long synchronization sequences Short synchronization sequences Signal a-priori known due to low data rates Complete signal not a-priori known to support high data rates, only certain pilots Very accurate synchronization of the satellites by atomic clocks Synchronization of the BSs not a-priori guaranteed Line of sight (LOS) access as normal case  not suitable for urban / indoor areas Non line of sight (NLOS) access as normal case  suitable for urban / indoor areas 3-dimensional positioning 2-dimensional positioning November 2012 | LTE Introduction | 117
  • 118. Measurements for positioning l UE-assisted measurements. l l l Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ). RSTD – Reference Signal Time Difference. UE Rx–Tx time difference. UL radio frame #i l eNB-assisted measurements. l l eNB Rx – Tx time difference. TADV – Timing Advance. – For positioning Type 1 is of relevance. l l Neighbor cell j RSTD – Relative time difference between a subframe received from neighbor cell j and corresponding subframe from serving cell i: TSubframeRxj - TSubframeRxi AoA – Angle of Arrival. UTDOA – Uplink Time Difference of Arrival. TADV (Timing Advance) = eNB Rx-Tx time difference + UE Rx-Tx time difference = (TeNB-RX – TeNB-TX) + (TUE-RX – TUE-TX) DL radio frame #i UL radio frame #i DL radio frame #i Serving cell i UE Rx-Tx time difference is defined as TUE-RX – TUE-TX, where TUE-RX is the received timing of downlink radio frame #i from the serving cell i and TUE-TX the transmit timing of uplink radio frame #i. RSRP, RSRQ are measured on reference signals of serving cell i eNB Rx-Tx time difference is defined as TeNB-RX – TeNB-TX, where TeNB-RX is the received timing of uplink radio frame #i and TeNB-TX the transmit timing of downlink radio frame #i. Source: see TS 36.214 Physical Layer measurements for detailed definitions November 2012 | LTE Introduction | 118
  • 119. Observed Time difference Observed Time Difference of Arrival OTDOA If network is synchronised, UE can measure time difference November 2012 | LTE Introduction | 119
  • 120. Methods‘ overview CID E-CID (AOA) [Triangulation] E-CID (RSRP/TOA/TADV) E-CID (RSRP/TOA/TADV) [Trilateration] Downlink / Uplink (O/U-TDOA) [Multilateration] RF Pattern matching To be updated!! November 2012 | LTE Introduction | 120
  • 121. Cell ID l Not new, other definition: Cell of Origin (COO). l l UE position is estimated with the knowledge of the geographical coordinates of its serving eNB. Position accuracy = One whole cell . November 2012 | LTE Introduction | 121
  • 122. Enhanced-Cell ID (E-CID) l UE positioning compared to CID is specified more accurately using additional UE and/or E UTRAN radio measurements: l E-CID with distance from serving eNB  position accuracy: a circle. – Distance calculated by measuring RSRP / TOA / TADV (RTT). l E-CID with distances from 3 eNB-s  position accuracy: a point. – Distance calculated by measuring RSRP / TOA / TADV (RTT). l E-CID with Angels of Arrival  position accuracy: a point. – AOA are measured for at least 2, better 3 eNB‘s. November 2012 | LTE Introduction | 122 RSRP – Reference Signal Received Power TOA – Time of Arrival TADV – Timing Advance RTT – Round Trip Time
  • 123. Angle of Arrival (AOA) l AoA = Estimated angle of a UE with respect to a reference direction (= geographical North), positive in a counterclockwise direction, as seen from an eNB. l l Determined at eNB antenna based on a received UL signal (SRS). Measurement at eNB: l l l l l eNB uses antenna array to estimate direction i.e. Angle of Arrival (AOA). The larger the array, the more accurate is the estimated AOA. eNB reports AOA to LS. Advantage: No synchronization between eNB‘s. Drawback: costly antenna arrays. November 2012 | LTE Introduction | 123
  • 124. OTDOA – Observed Time Difference of Arrival l UE position is estimated based on measuring TDOA of Positioning Reference Signals (PRS) embedded into overall DL signal received from different eNB’s. l l Each TDOA measurement describes a hyperbola (line of constant difference 2a), the two focus points of which (F1, F2) are the two measured eNB-s (PRS sources), and along which the UE may be located. UE’s position = intersection of hyperbolas for at least 3 pairs of eNB’s. November 2012 | LTE Introduction | 124
  • 125. Positioning Reference Signals (PRS) for OTDOA Definition l Cell-specific reference signals (CRS) are not sufficient for positioning, introduction of positioning reference signals (PRS) for antenna port 6. l l SINR for synchronization and reference signals of neighboring cells needs to be at least -6 dB. PRS is a pseudo-random QPSK sequence similar to CRS; PRS pattern: l l Diagonal pattern with time varying frequency shift. PRS mapped around CRS to avoid collisions; never overlaps with PDCCH; example shows CRS mapping for usage of 4 antenna ports. November 2012 | LTE Introduction | 125
  • 126. Uplink (UTDOA) l l UTDOA = Uplink Time Difference of Arrival UE positioning estimated based on: – measuring TDOA of UL (SRS) signals received in different eNB-s – each TDOA measurement describes a hyperbola (line of constant difference 2a), the 2 focus points of which (F1, F2) are the two receiving eNB-s (SRS receiptors), and along which the UE may be located. – UE’s position = intersection of hyperbolas for at least three pairs of eNB-s (= 3 eNB-s) – knowledge of the geographical coordinates of the measured eNode Bs l Method as such not specified for LTE  Similarity to 3G assumed - eNB-s measure and report to eNB_Rx-Tx to LS -LS calculates UTDOA and estimates the UE position Location Server November 2012 | LTE Introduction | 126
  • 127. IMT-Advanced Requirements l l l l l l l l A high degree of commonality of functionality worldwide while retaining the flexibility to support a wide range of services and applications in a cost efficient manner, Compatibility of services within IMT and with fixed networks, Capability of interworking with other radio access systems, High quality mobile services, User equipment suitable for worldwide use, User-friendly applications, services and equipment, Worldwide roaming capability; and Enhanced peak data rates to support advanced services and applications, l l 100 Mbit/s for high and 1 Gbit/s for low mobility were established as targets for research, November 2012 | LTE Introduction | 127
  • 128. Do you Remember? Targets of ITU IMT-2000 Program (1998) IMT-2000 The ITU vision of global wireless access in the 21st century Global Satellite Suburban Macrocell Urban Microcell In-Building Picocell Basic Terminal PDA Terminal Audio/Visual Terminal l Flexible and global – Full coverage and mobility at 144 kbps .. 384 kbps – Hot spot coverage with limited mobility at 2 Mbps – Terrestrial based radio access technologies l The IMT-2000 family of standards now supports four different multiple access technologies: l FDMA, TDMA, CDMA (WCDMA) and OFDMA (since 2007) November 2012 | LTE Introduction | 128
  • 129. IMT Spectrum MHz MHz Next possible spectrum allocation at WRC 2015! MHz MHz November 2012 | LTE Introduction | 129
  • 130. Expected IMT-Advanced candidates Long Term Evolution Ultra Mobile Broadband Advanced Mobile WiMAX Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008 November 2012 | LTE Introduction | 130
  • 131. IMT – International Mobile Communication l IMT-2000 l l l l Was the framework for the third Generation mobile communication systems, i.e. 3GPP-UMTS and 3GPP2-C2K Focus was on high performance transmission schemes: Link Level Efficiency Originally created to harmonize 3G mobile systems and to increase opportunities for worldwide interoperability, the IMT-2000 family of standards now supports four different access technologies, including OFDMA (WiMAX), FDMA, TDMA and CDMA (WCDMA). IMT-Advanced l l l Basis of (really) broadband mobile communication Focus on System Level Efficiency (e.g. cognitive network systems) Vision 2010 – 2015 November 2012 | LTE Introduction | 131
  • 132. LTE-Advanced Possible technology features Relaying technology Wider bandwidth support Enhanced MIMO schemes for DL and UL Cooperative base stations Interference management methods Cognitive radio methods Radio network evolution Further enhanced MBMS November 2012 | LTE Introduction | 132
  • 133. Bandwidth extension with Carrier aggregation November 2012 | LTE Introduction | 133
  • 134. LTE-Advanced Carrier Aggregation Component carrier CC Contiguous carrier aggregation Non-contiguous carrier aggregation November 2012 | LTE Introduction | 134
  • 135. Aggregation l Contiguous l l Intra-Band Non-Contiguous l l l Intra (Single) -Band Inter (Multi) -Band Combination l l Up to 5 Rel-8 CC and 100 MHz Theoretically all CC-BW combinations possible (e.g. 5+10+20 etc) November 2012 | LTE Introduction | 135
  • 136. Carrier aggregation (CA) General comments l Two or more component carriers are aggregated in LTE-Advanced in order to support wider bandwidths up to 100 MHz. l Support for contiguous and noncontiguous component carrier aggregation (intra-band) and inter-band carrier aggregation. l l l Different bandwidths per component carrier (CC) are possible. Each CC limited to a max. of 110 RB using the 3GPP Rel-8 numerology (max. 5 carriers, 20 MHz each). Motivation. l l Intra-band contiguous Frequency band A Component Carrier (CC) Frequency band B Intra-band non-contiguous Frequency band A Frequency band B 2012 © by Rohde&Schwarz Inter-band Frequency band A Frequency band B Higher peak data rates to meet IMT-Advanced requirements. NW operators: spectrum aggregation, enabling Heterogonous Networks. November 2012 | LTE Introduction | 136
  • 137. Overview l Carrier Aggregation (CA) enables to aggregate up to 5 different cells (component carriers CC), so that a maximum system bandwidth of 100 MHz can be supported (LTE-Advanced requirement). l Each CC = Rel-8 autonomous cell l CC-Set is UE specific – Registration  Primary (P)CC – Additional BW  Secondary (S)CC-s 1-4 l UE1 UE4 UE3 Network perspective – Same single RLC-connection for one UE (independent on the CC-s) – Many CC (starting at MAC scheduler) operating the UE l Cell 2 Cell 1 – Backwards compatibility U3 CC1 UE1 CC2 For TDD – Same UL/DL configuration for all CC-s November 2012 | LTE Introduction | UE4 137 CC2 CC1 UE3 UE4 UE2 U2
  • 138. Carrier aggregation (CA) General comments, cont’d. l A device capable of carrier aggregation has 1 DL primary component carrier and 1 associated primary UL component carrier. l Basic linkage between DL and UL is signaled in SIB Type 2. l Configuration of primary component carrier (PCC) is UE-specific. – Downlink: cell search / selection, system information, measurement and mobility. – Uplink: access procedure on PCC, control information (PUCCH) on PCC. – Network may decide to switch PCC for a device  handover procedure is used. l Device may have one or several secondary component carriers. Secondary Component Carriers (SCC) added in RRC_CONNECTED mode only. – Symmetric carrier aggregation. – Asymmetric carrier aggregation (= Rel-10). Downlink SCC SCC SCC Uplink PCC SCC PCC SCC SCC 2012 © by Rohde&Schwarz PDSCH and PDCCH PUSCH and PUCCH PDSCH, PDCCH is optional November 2012 | LTE Introduction | PUSCH only 138 SCC SCC
  • 139. LTE-Advanced Carrier Aggregation – Initial Deployment l l Initial LTE-Advanced deployments will likely be limited to the use of two component carrier. The below are focus scenarios identified by 3GPP RAN4. November 2012 | LTE Introduction | 139
  • 140. Bandwidth l  BWChannel(1)  BWChannel( 2)  0.1 BWChannel(1)  BWChannel( 2) Nominal channel spacing   0.6   General – Up to 5 CC – Up to 100 RB-s pro CC – Up to 500 RB-s aggregated l Aggregated transmission bandwidth – Sum of aggregated channel bandwidths – Illustration for Intra band contiguous – Channel raster 300 kHz l Bandwidth classes – UE Capability November 2012 | LTE Introduction | 140  0.3 MHz  
  • 141. Bands / Band-Combinations (II) l Under discussion l 25 WI-s in RAN4 with practical interest – Inter band (1 UL CC) – Intra band cont (1 UL CC) – Intra band non cont (1 UL CC) – Inter band (2 UL CC) l Release independency l Band performance is release independent – Band introduced in Rel-11 – Performance tested for Rel10 November 2012 | LTE Introduction | 141
  • 142. Carrier aggregation - configurations l CA Configurations l E-UTRA CA Band + Allowed BW = CA Configuration – Intra band contiguous – Most requirements – Inter band – Some requirements – Main interest of many companies – Intra band non contiguous – No configuration / requirements – Feature of later releases? l CA Requirement applicability – CL_X  Intra band CA – CL_X-Y  Inter band – Non-CA  no CA (explicitely stated for the Test point which are tested differently for CA and not CA) November 2012 | LTE Introduction | 142
  • 143. UE categories for Rel-10 NEW! UE categories 6…8 (DL and UL) UE Category Maximum number of DL-SCH transport block bits received within a TTI Maximum number of bits of a DL-SCH transport block received within a TTI Total number of soft channel bits Maximum number of supported layers for spatial multiplexing in DL … … … … … Category 6 301504 149776 (4 layers) 75376 (2 layers) 3654144 2 or 4 Category 7 301504 149776 (4 layers) 75376 (2 layers) 3654144 2 or 4 Category 8 2998560 299856 35982720 8 ~3 Gbps peak DL data rate for 8x8 MIMO 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 Support for 64Q AM in UL … … … … Category 6 51024 51024 No Category 7 102048 51024 No Category 8 1497760 149776 Yes November 2012 | LTE Introduction | 143 ~1.5 Gbps peak UL data rate, 4x4 MIMO Total layer 2 buffer size [bytes] … 3 300 000 3 800 000 42 200 000
  • 144. Deployment scenarios 3) Improve coverage l l l l #1: Contiguous frequency aggregation – – Co-located & Same coverage Same f #2: Discontiguous frequency aggregation – – Co-located & Similar coverage Different f #3: Discontiguous frequency aggregation – – – Co-Located & Different coverage Different f Antenna direction for CC2 to cover blank spots #4: Remote radio heads – – – – l F1 Not co-located Intelligence in central eNB, radio heads = only transmission antennas Cover spots with more traffic Is the transmission of each radio head within the cell the same? #5:Frequency-selective repeaters – – – Combination #2 & #4 Different f Extend the coverage of the 2nd CC with Relays November 2012 | LTE Introduction | 144 F2
  • 145. Physical channel arrangement in downlink Each component carrier transmits PSCH and S-SCH, Like Rel.8 Each component carrier transmits PBCH, Like Rel.8 November 2012 | LTE Introduction | 145
  • 146. LTE-Advanced Carrier Aggregation – Scheduling Contiguous Non-Contiguous spectrum allocation RLC transmission buffer Dynamic switching Channel coding Channel coding Channel coding Channel coding HARQ HARQ HARQ HARQ Data mod. Data mod. Data mod. Data mod. Mapping Mapping Mapping Mapping e.g. 20 MHz Each component Carrier may use its own AMC, = modulation + coding scheme [frequency in MHz] November 2012 | LTE Introduction | 146
  • 147. Carrier Aggregation – Architecture downlink 1 UE using carrier aggregation Radio Bearers Radio Bearers ROHC ... ROHC Security RLC ROHC ... ROHC ... Security Segm. ARQ etc ... Segm. ARQ etc Security PDCP Security ... ROHC Security ROHC ... PDCP ... Security Segm. ARQ etc ... Segm. ARQ etc Segm. Segm. RLC Segm. ARQ etc ... Segm. ARQ etc CCCH CCCH BCCH PCCH MCCH Logical Channels Unicast Scheduling / Priority Handling Multiplexing UE1 ... MTCH HARQ ... HARQ Multiplexing Multiplexing UEn HARQ ... Scheduling / Priority Handling MBMS Scheduling MAC Logical Channels Multiplexing MAC HARQ HARQ ... HARQ Transport Channels Transport Channels DL-SCH on CC1 DL-SCH on CCx DL-SCH on CC1 DL-SCH on CCy BCH PCH UL-SCH on CC1 MCH UL-SCH on CCz In case of CA, the multi-carrier nature of the physical layer is only exposed to the MAC layer for which one HARQ entity is required per serving cell November 2012 | LTE Introduction | 147
  • 148. Common or separate PDCCH per Component Carrier? l l PDCCH on a component carrier can assign PDSCH or PUSCH resources in one of multiple component carriers using the carrier indicator field. Rel-8 DCI formats extended with 3 bit carrier indicator field. Reusing Rel-8 PDCCH structure (same coding, same CCE-based resource mapping). November 2012 | LTE Introduction | PDSCH PDSCH PDSCH No cross-carrier scheduling 148 PDCCH 1 slot = 0.5 ms PDCCH PDCCH 1 subframe = 1 ms PDCCH l PDCCH Cross-carrier scheduling. Time PDCCH l PDCCH on a component carrier assigns PDSCH resources on the same component carrier (and PUSCH resources on a single linked UL component carrier). Reuse of Rel-8 PDCCH structure (same coding, same CCE-based resource mapping) and DCI formats. Frequency l l up to 3 (4) symbols per subframe No cross-carrier scheduling. PCC l PDSCH PDSCH PDSCH Cross-carrier scheduling
  • 149. Carrier aggregation: control signals + scheduling Each CC has its own control channels, like Rel.8 Femto cells: Risk of interference! -> main component carrier will send all control information. November 2012 | LTE Introduction | 149
  • 150. DCI control elements: CIF field New field: carrier indicator field gives information, which component carrier is valid. => reminder: maximum 5 component carriers! Carrier Indicator Field, CIF, 3bits f Component carrier 1 f f Component carrier N Component carrier 2 November 2012 | LTE Introduction | 150
  • 151. PDSCH start field e.g. PCC Primary component carrier PCFICH R PCFICH R PCFICH R Example: 1 Resource block Of a component carrier PDCCH e.g. SCC Secondary component carrier PDSCH start field indicates position In cross-carrier scheduling,the UE does not read the PCFICH andPDCCH on SCC, thus it has to know the start of the PDSCH November 2012 | LTE Introduction | 151
  • 152. Component Carrier – RACH configuration Downlink Asymmetric carrier Aggregation possible, e.g. DL more CC than UL Uplink All CC use same RACH preamble Each CC has its own RACH Network responds on all CCs Only 1 CC contains RACH November 2012 | LTE Introduction | 152
  • 153. Carrier Aggregation l The transmission mode is not constrained to be the same on all CCs scheduled for a UE l A single UE-specific UL CC is configured semi-statically for carrying PUCCH A/N, SR, and periodic CSI from a UE l Frequency hopping is not supported simultaneously with non-contiguous PUSCH resource allocation l UCI cannot be carried on more than one PUSCH in a given subframe. November 2012 | LTE Introduction | 153
  • 154. Carrier Aggregation l Working assumption is confirmed that a single set of PHICH resources is shared by all UEs (Rel-8 to Rel-10) l If simultaneous PUCCH+PUSCH is configured and there is at least one PUSCH transmission l l UCI can be transmitted on either PUCCH or PUSCH with a dependency on the situation that needs to be further discussed All UCI mapped onto PUSCH in a given subframe gets mapped onto a single CC irrespective of the number of PUSCH CCs November 2012 | LTE Introduction | 154
  • 155. UE Architectures l Possible TX architectures l l Same / Different antenna (connectors) for each CC D1/D2 could be switched to support CA or UL MIMO November 2012 | LTE Introduction | 155
  • 156. LTE–Advanced solutions from R&S R&S® SMU200 Vector Signal Generator November 2012 | LTE Introduction | 156
  • 157. LTE–Advanced solutions from R&S R&S® FSQ Signal Analyzer RBW 2 MHz VBW 5 MHz Ref -20 dBm Att 5 dB SWT 2.5 ms -20 A -30 1 AP CLRWR -40 -10 dB -50 -60 20 MHz -70 E-UTRA carrier 2 20 MHz E-UTRA carrier 2 fc,E-UTRA carrier 2 = 2135 MHz fc,E-UTRA carrier 2 = 2205 MHz3DB -80 -90 -100 -110 -120 Center 2.17 GHz Date: 8.OCT.2009 EXT 10 MHz/ LTE-Advanced – An introduction November 2012 | LTE Introduction | 14:13:24 Roessler | October 2009 | 157 A. Span 157 100 MHz
  • 158. Enhanced MIMO schemes l Increased number of layers: l l l Up to 8x8 MIMO in downlink. Up to 4x4 MIMO in uplink. In addition the downlink reference signal structure has been enhanced compared with LTE Release 8 by: l Demodulation Reference signals (DM-RS) targeting PDSCH demodulation. – UE specific, i.e. an extension to multiple layers of the concept of Release 8 UEspecific reference signals used for beamforming. l Reference signals targeting channel state information (CSI-RS) estimation for CQI/PMI/RI/etc reporting when needed. – Cell specific, sparse in the frequency and time domain and punctured into the data region of normal subframes. November 2012 | LTE Introduction | 158
  • 159. Cell specific Reference Signals vs. DM-RS LTE Rel.8 LTE-Advanced (Rel.10) CRS0 s1 CRS0 + CSI-RS0 s1 s2 s2 ........ ........ Precoding sN Precoding sN Cell specific Reference signalsN l DM-RS0 DM-RSN Cell specific reference signalsN + Channel status information reference signals 0 Demodulation-Reference signals DM-RS and data are precoded the same way, enabling non-codebook based precoding and enhanced multi-user beamforming. November 2012 | LTE Introduction | 159
  • 160. Ref. signal mapping: Rel.8 vs. LTE-Advanced l LTE (Release 8) Example: l LTE-A (Release 10) 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 x x x x x x x x x x x x x x x x x x x x x PDSCH PDCCH CRS x x x x DM-RS R E L E A S E x l CRS sent on all RBs; DTX sent for the CRS of 2nd antenna port. l DM-RS sent only for scheduled RBs on all antennas; each set coded differently between the two layers. l CSI-RS punctures Rel. 8 data; sent periodically over allotted REs (not more than twice per frame) x 8 x x x l 1 0 x R E L E A S E x 2 antenna ports, antenna port 0, CSI-RS configuration 8. PDCCH (control) allocated in the first 2 OFDM symbols. CSI-RS November 2012 | LTE Introduction | 160
  • 161. DL MIMO Extension up to 8x8 Codeword to layer mapping for spatial multiplexing l l Max number of transport blocks: 2 Number of MCS fields l l l l l layer i  0,1, M symb  1 x ( 0) (i)  d ( 0) (2i) x (1) (i)  d ( 0) (2i  1) 1 bit per transport block for evaluation as a baseline 5 2 x (i)  d (3i ) x (3) (i )  d (1) (3i  1) x ( 4) (i)  d (1) (3i  2) ( 2) Rely on precoded dedicated demodulation RS (decision on DL RS) Conclusion on the codeword-tolayer mapping: l Codeword-to-layer mapping one for each transport block Closed-loop precoding supported l l Number of code words ACK/NACK feedback l l Number of layers DL spatial multiplexing of up to eight layers is considered for LTE-Advanced, Up to 4 layers, reuse LTE codeword-tolayer mapping, Above 4 layers mapping – see table (1) layer ( 0) (1) M symb  M symb 2  M symb 3 x ( 0) (i )  d ( 0) (3i) x (1) (i )  d ( 0) (3i  1) x ( 2) (i)  d ( 0) (3i  2) 6 layer ( 0) (1) M symb  M symb 3  M symb 3 2 x (3) (i)  d (1) (3i) x ( 4) (i)  d (1) (3i  1) x (5) (i )  d (1) (3i  2) x ( 0) (i )  d ( 0) (3i) x (1) (i )  d ( 0) (3i  1) x ( 2) (i)  d ( 0) (3i  2) 7 2 Discussion on control signaling details ongoing x (3) (i )  d (1) (4i ) x ( 4) (i )  d (1) (4i  1) x (5) (i )  d (1) (4i  2) x ( 6) (i )  d (1) (4i  3) x ( 0) (i )  d ( 0) (4i ) x (1) (i )  d ( 0) (4i  1) x ( 2) (i )  d ( 0) (4i  2) x (3) (i )  d ( 0) (4i  3) 8 November 2012 | LTE Introduction | 2 161 x ( 4) (i)  d (1) (4i) x (5) (i)  d (1) (4i  1) x ( 6) (i )  d (1) (4i  2) x ( 7 ) (i)  d (1) (4i  3) layer ( 0) (1) M symb  M symb 3  M symb 4 layer ( 0) (1) M symb  M symb 4  M symb 4
  • 162. MIMO – layer and codeword 101 Codeword 1: 111000011101 101 Codeword 1: 111000011101 100 011 ACK 000 Codeword 2: 010101010011 Codeword 2: 010101010011 111 001 111 ACK Up to 8 times the data -> 8 layers Receiver only Sends 2 ACK/NACKs November 2012 | LTE Introduction | 162
  • 163. Uplink MIMO Extension up to 4x4 l Rel-8 LTE. l l l UEs must have 2 antennas for reception. But only 1 amplifier for transmission is available (costs/complexity). UL MIMO only as antenna switching mode (switched diversity). l 4x4 UL SU-MIMO is needed to fulfill peak data rate requirement of 15 bps/Hz. l Schemes are very similar to DL MIMO modes. l l l UL spatial multiplexing of up to 4 layers is considered for LTE-Advanced. SRS enables link and SU-MIMO adaptation. Number of receive antennas are receiver-implementation specific. l At least two receive antennas is assumed on the terminal side. November 2012 | LTE Introduction | 163
  • 164. UL MIMO – signal generation in uplink Similar to Rel.8 Downlink: layers codewords Scrambling Modulation mapper antenna ports Transform precoder Layer mapper Scrambling Avoid periodic bit sequence Modulation mapper QPSK 16-QAM 64-QAM Resource element mapper Resource element mapper SC-FDMA signal gen. Precoding Transform precoder Up to 4 layer SC-FDMA signal gen. DFT, as in Rel 8, but noncontiguous allocation possible November 2012 | LTE Introduction | 164
  • 165. LTE-Advanced Enhanced uplink SC-FDMA l l l The uplink transmission scheme remains SC-FDMA. The transmission of the physical uplink shared channel (PUSCH) uses DFT precoding. Two enhancements: l l Control-data decoupling Non-contiguous data transmission November 2012 | LTE Introduction | 165
  • 166. Physical channel arrangement - uplink Clustered-DFTS-OFDM = Clustered DFT spread OFDM. Simultaneous transmission of PUCCH and PUSCH from the same UE is supported Non-contiguous resource block allocation => will cause higher Crest factor at UE side November 2012 | LTE Introduction | 166
  • 167. LTE-Advanced Enhanced uplink SC-FDMA Due to distribution we get active subcarriers beside non-active subcarriers: worse peak to average ratio, e.g. Crest factor November 2012 | LTE Introduction | 167
  • 168. What are the effects of “Enhanced SC-FDMA”? Source: http://www.3gpp.org/ftp/tsg_ran/WG4_Radio/TSGR4_54/Documents/R4-101056.zip November 2012 | LTE Introduction | 168
  • 169. Simultaneous PUSCH-PUCCH transmission, multicluster transmission l Remember, only one UL carrier in 3GPP Release 10; scenarios: l Feature support is indicated by PhyLayerParameters-v1020 IE*). PUCCH and allocated PUSCH PUCCH and fully allocated PUSCH f [MHz] PUCCH f [MHz] PUSCH partially allocated PUSCH PUCCH and partially allocated PUSCH f [MHz] f [MHz] *) see November 2012 | LTE Introduction | 169 3GPP TS 36.331 RRC Protocol Specification
  • 170. Benefit of localized or distributed mode „static UE“: frequency selectivity is not time variant -> localized allocation Multipath causes frequency Selective channel, It can be time variant or Non-time variant „high velocity UE“: frequency selectivity is time variant -> distributed allocation November 2012 | LTE Introduction | 170
  • 171. Significant step towards 4G: Relaying ? Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008 November 2012 | LTE Introduction | 171
  • 172. Radio Relaying approach No Improvement of SNR resp. CINR Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008 November 2012 | LTE Introduction | 172
  • 173. L1/L2 Relaying approach Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008 November 2012 | LTE Introduction | 173
  • 174. Present Thrust- Spectrum Efficiency Momentary snapshot of frequency spectrum allocation Why not use this part of the spectrum? l FCC Measurements:- Temporal and geographical variations in the utilization of the assigned spectrum range from 15% to 85%. November 2012 | LTE Introduction | 174
  • 175. ODMA – some ideas… BTS Mobile devices behave as relay station ODMA = opportunity driven multiple access November 2012 | LTE Introduction | 175
  • 176. Cooperative communication How to implement antenna arrays in mobile handsets? Multi-access Independent fading paths Each mobile is user and relay 3 principles of aid: •Amplify and forward •Decode and forward •Coded cooperation November 2012 | LTE Introduction | 176
  • 177. Cooperative communication Multi-access Independent fading paths Higher signaling System complexity Cell edge coverage Group mobility Virtual Antenna Array November 2012 | LTE Introduction | 177
  • 178. LTE, UMTS Long Term Evolution LTE measurements – from RF to application testing Reiner Stuhlfauth Reiner.Stuhlfauth@rohde-schwarz.com Training Centre Rohde & Schwarz, Germany Subject to change – Data without tolerance limits is not binding. R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarks of the owners.  2011 ROHDE & SCHWARZ GmbH & Co. KG Test & Measurement Division - Training Center This folder may be taken outside ROHDE & SCHWARZ facilities. ROHDE & SCHWARZ GmbH reserves the copy right to all of any part of these course notes. Permission to produce, publish or copy sections or pages of these notes or to translate them must first be obtained in writing from ROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany
  • 179. Mobile Communications: Fields for testing l RF testing for mobile stations and user equipment l RF testing for base stations l Drive test solutions and verification of network planning l Protocol testing, signaling behaviour l Testing of data end to end applications l Audio and video quality testing l Spectrum and EMC testing November 2012 | LTE Introduction | 179
  • 180. Test Architecture RF-/L3-/IP Application-Test November 2012 | LTE Introduction | 180
  • 181. LTE measurements general aspects November 2012 | LTE Introduction | 181
  • 182. LTE RF Testing Aspects UE requirements according to 3GPP TS 36.521 Power Transmit signal quality  Maximum output power  Maximum power reduction  Additional Maximum Power Reduction  Minimum output power  Configured Output Power  Power Control  Absolution Power Control  Relative Power Control  Aggregate Power Control  ON/OFF Power time mask 36.521: User Equipment (UE) radio transmission and reception Frequency error Modulation quality, EVM Carrier Leakage In-Band Emission for non allocated RB EVM equalizer spectrum flatness Output RF spectrum emissions  Occupied bandwidth  Out of band emissions  Spectrum emisssion mask  Additional Spectrum emission mask  Adjacent Channel Leakage Ratio Transmit Intermodulation November 2012 | LTE Introduction | 182
  • 183. LTE RF Testing Aspects UE requirements according to 3GPP, cont. Receiver characteristics:  Reference sensitivity level  Maximum input level  Adjacent channel selectivity  Blocking characteristics  In-band Blocking  Out of band Blocking  Narrow Band Blocking  Spurious response  Intermodulation characteristics  Spurious emissions Performance November 2012 | LTE Introduction | 183
  • 184. LTE bands and channel bandwidth E-UTRA band / channel bandwidth E-UTRA Band 1.4 MHz 3 MHz 10 MHz 15 MHz 20 MHz Yes 1 5 MHz Yes Yes Yes Yes[1] 2 Yes Yes Yes Yes Yes[1] 3 Yes Yes Yes Yes Yes[1] Yes[1] 4 Yes Yes Yes Yes Yes Yes 5 Yes Yes Yes Yes[1] 6 Yes Yes[1] 7 Yes Yes Yes Yes[1] Yes Yes[1] 9 Yes Yes Yes[1] Yes[1] 10 Yes Yes Yes Yes Yes Yes[1] Yes[1] Yes[1] 13 Yes[1] Yes[1] 14 Yes[1] Yes[1] Yes[1] Yes[1] 33 Yes Yes Yes 34 Yes Yes Yes 8 Yes Yes 11 12 Yes Yes ... 17 ... Not every channel bandwidth for every band! Yes 35 Yes Yes Yes Yes Yes Yes 36 Yes Yes Yes Yes Yes Yes 37 Yes Yes Yes Yes 38 Yes Yes Yes Yes 39 Yes Yes Yes Yes 40 Yes Yes Yes Yes NOTE 1: bandwidth for which a relaxation of the specified UE receiver sensitivity requirement (Clause 7.3) is allowed. November 2012 | LTE Introduction | 184
  • 185. RF power Tests performed at “low, mid and highest frequency” Nominal frequency described by EARFCN (E-UTRA Absolute Radio Frequency Channel Number) lowest EARFCN possible and 1 RB at position 0 RF power Frequency = whole LTE band mid EARFCN and 1 RB at position 0 RF power Frequency Highest EARFCN and 1 RB at max position Frequency November 2012 | LTE Introduction | 185
  • 186. LTE RF measurements on user equipment UEs November 2012 | LTE Introduction | 186
  • 187. LTE Transmitter Measurements 1 1.1 1.2 1.3 1.4 2 2.1 2.2 2.3 2.3.1 2.3.2 2.3.3 2.4 2.4.1 2.4.2 2.4.3 3 3.1 3.2 3.2.1 3.2.2 3.2.3 3.2.4 4 4.1 4.2 4.2.1 4.2.2 4.2.3 4.3 4.3.1 4.3.2 4.3.3 5 Transmit power UE Maximum Output Power Maximum Power Reduction (MPR) Additional Maximum Power Reduction (A-MPR) Configured UE transmitted Output Power Output Power Dynamics Minimum Output Power Transmit OFF power ON/OFF time mask General ON/OFF time mask PRACH time mask SRS time mask Power Control Power Control Absolute power tolerance Power Control Relative power tolerance Aggregate power control tolerance Transmit signal quality Frequency Error Transmit modulation Error Vector Magnitude (EVM) Carrier leakage In-band emissions for non allocated RB EVM equalizer spectrum flatness Output RF spectrum emissions Occupied bandwidth Out of band emission Spectrum Emission Mask Additional Spectrum Emission Mask Adjacent Channel Leakage power Ratio Spurious emissions Transmitter Spurious emissions Spurious emission band UE co-existence Additional spurious emissions Transmit intermodulation November 2012 | LTE Introduction | 187
  • 188. UE Signal quality – symbolic structure of mobile radio tester MRT Test equipment Rx … … … DUT RF correction l l l l l IDFT FFT … … … l TxRx equalizer Inbandemmissions Carrier Frequency error EVM (Error Vector Magnitude) Origin offset + IQ offset Unwanted emissions, falling into non allocated resource blocks. Inband transmission Spectrum flatness November 2012 | LTE Introduction | 188 EVM meas.
  • 189. UL Power Control: Overview UL-Power Control is a combination of: l Open-loop: UE estimates the DL-Pathloss and compensates it for the UL l Closed-loop: in addition, the eNB controls directly the ULPower through powercontrol commands transmitted on the DL November 2012 | LTE Introduction | 189
  • 190. PUSCH power control l Power level [dBm] of PUSCH is calculated every subframe i based on the following formula out of TS 36.213 MPR Maximum allowed UE power in this particular cell, but at maximum +23 dBm1) Combination of cell- and UE-specific components configured by L3 Number of allocated resource blocks (RB) Transmit power for PUSCH in subframe i in dBm Bandwidth factor 1) Cell-specific parameter configured by L3 PUSCH transport format Downlink path loss estimate Power control adjustment derived from TPC command received in subframe (i-4) Basic open-loop starting point Dynamic offset (closed loop) +23 dBm is maximum allowed power in LTE according to TS 36.101, corresponding to power class 3bis in WCDMA November 2012 | LTE Introduction | 190
  • 191. LTE RF Testing: UE Maximum Power UE transmits with 23dBm ±2 dB QPSK modulation is used. All channel bandwidths are tested separately. Max power is for all band classes Test is performed for varios uplink allocations November 2012 | LTE Introduction | 191
  • 192. RF power Resource Blocks number and maximum RF power 1 active resource block (RB), Nominal band width 10 MHz = 50 RB’s RF power Frequency One active resource block (RB) provides maximum absolute RF power More RB’s in use will be at lower RF power in order to create same integrated power RF power Frequency MPR Additionally, MPR (Max. Power Reduction) and AMPR are defined Frequency November 2012 | LTE Introduction | 192
  • 193. UE maximum power PPowerClass + 2dB 23dBm PPowerClass - 2dB FUL_low maximum output power for any transmission bandwidth within the channel bandwidth November 2012 | LTE Introduction | 193 FUL_high
  • 194. UE maximum power – careful at band edge! PPowerClass + 2dB 23dBm PPowerClass - 2dB -1.5dB FUL_low FUL_low+4MHz FUL_high- 4MHz -1.5dB FUL_high For transmission bandwidths confined within FUL_low and FUL_low + 4 MHz or FUL_high – 4 MHz and FUL_high, the maximum output power requirement is relaxed by reducing the lower tolerance limit by 1.5 dB November 2012 | LTE Introduction | 194
  • 195. LTE RF Testing: UE Minimum Power UE transmits with -40dBm All channel bandwidths are tested separately. Minimum power is for all band classes < -39 dBm November 2012 | LTE Introduction | 195
  • 196. LTE RF Testing: UE Off Power The transmit OFF power is defined as the mean power in a duration of at least one sub-frame (1ms) excluding any transient periods. The transmit OFF power shall not exceed the values specified in table below Channel bandwidth / Minimum output power / measurement bandwidth 1.4 MHz 3.0 MHz 10 MHz 15 MHz 20 MHz 13.5 MHz 18 MHz -50 dBm Transmit OFF power Measurement bandwidth 5 MHz 1.08 MHz 2.7 MHz 4.5 MHz November 2012 | LTE Introduction | 9.0 MHz 196
  • 197. Configured UE transmitted Output Power IE P-Max (SIB1) = PEMAX To verify that UE follows rules sent via system information, SIB Test: set P-Max to -10, 10 and 15 dBm, measure PCMAX Channel bandwidth / maximum output power 1.4 MHz 3.0 MHz 5 MHz 10 MHz PCMAX test point 1 -10 dBm ± 7.7 PCMAX test point 2 10 dBm ± 6.7 PCMAX test point 3 15 dBm ± 5.7 November 2012 | LTE Introduction | 197 15 MHz 20 MHz
  • 198. LTE Power versus time RB allocation is main source for power change Not scheduled Resource block PPUSCH (i)  min{PMAX ,10 log10 (M PUSCH (i))  PO_PUSCH ( j )    PL   TF (TF (i))  f (i)} Bandwidth allocation Given by higher layers TPC commands or not used November 2012 | LTE Introduction | 198
  • 199. Accumulative TPC commands TPC Command Field In DCI format 0/3 Accumulated  PUSCH [dB] 0 -1 1 0 2 1 3 3 2 minimum power in LTE November 2012 | LTE Introduction | 199
  • 200. Absolute TPC commands PPUSCH (i)  min{ PMAX ,10 log 10 ( M PUSCH (i))  PO_PUSCH ( j )    PL   TF (TF (i))  f (i)} TPC Command Field In DCI format 0/3 Absolute  PUSCH [dB] only DCI format 0 0 -4 1 -1 2 1 3 4 Pm -1 -4 November 2012 | LTE Introduction | 200
  • 201. Relative Power Control Power pattern B Power pattern A RB change RB change 0 .. 1 9 sub-frame# 2 3 4 radio frame Power pattern C 9 sub-frame# 2 3 9 sub-frame# 2 3 4 radio frame l The purpose of this test is to verify RB change 0 .. 1 0 .. 1 4 radio frame the ability of the UE transmitter to set its output power relatively to the power in a target sub-frame, relatively to the power of the most recently transmitted reference sub-frame, if the transmission gap between these subframes is ≤ 20 ms. November 2012 | LTE Introduction | 201
  • 202. Power Control – Relative Power Tolerance l Various power ramping patterns are defined ramping down alternating ramping up November 2012 | LTE Introduction | 202
  • 203. UE power measurements – relative power change Power Power FDD test patterns 0 1 Sub-test TDD test patterns 9 sub-frame# Uplink RB allocation 0 TPC command 2 3 7 8 Expected power step size (Up or down) test for each bandwidth, here 10MHz 9 sub-frame# Power step size range (Up or down) PUSCH/ ΔP [dB] ΔP [dB] [dB] 1 ΔP < 2 1 ± (1.7) A Fixed = 25 Alternating TPC = +/-1dB B Alternating 10 and 18 TPC=0dB 2.55 2 ≤ ΔP < 3 2.55 ± (3.7) C Alternating 10 and 24 TPC=0dB 3.80 3 ≤ ΔP < 4 3.80 ± (42.) D Alternating 2 and 8 TPC=0dB 6.02 4 ≤ ΔP < 10 6.02 ± (4.7) E Alternating 1 and 25 TPC=0dB 13.98 10 ≤ ΔP < 15 13.98 ± (5.7) F Alternating 1 and 50 TPC=0dB 16.99 15 ≤ ΔP 16.99 ± (6.7) November 2012 | LTE Introduction | 203
  • 204. UE aggregate power tolerance Aggregate power control tolerance is the ability of a UE to maintain its power in non-contiguous transmission within 21 ms in response to 0 dB TPC commands TPC command UL channel Aggregate power tolerance within 21 ms 0 dB PUCCH ±2.5 dB 0 dB PUSCH ±3.5 dB Note: 1. The UE transmission gap is 4 ms. TPC command is transmitted via PDCCH 4 subframes preceding each PUCCH/PUSCH transmission. Tolerated UE power deviation P UE power with TPC = 0 Time = 21 milliseconds November 2012 | LTE Introduction | 204
  • 205. UE aggregate power tolerance Power Power FDD test patterns 0 5 sub-frame# 0 5 TDD test patterns 0 3 8 sub-frame# 3 8 3 Test performed with scheduling gap of 4 subframes November 2012 | LTE Introduction | 205
  • 206. UE power measurement – timing masks Start Sub-frame Start of ON power End sub-frame End of ON power End of OFF power requirement Start of OFF power requirement * The OFF power requirements does not apply for DTX and measurement gaps 20µs 20µs Transient period Transient period Timing definition OFF – ON commands Timing definition ON – OFF commands November 2012 | LTE Introduction | 206
  • 207. Power dynamics PUSCH = OFF PUSCH = ON PUSCH = OFF Please note: scheduling cadence for power dynamics November 2012 | LTE Introduction | 207 time
  • 208. Tx power aspects RB power = Ressource Block Power, power of 1 RB TX power = integrated power of all assigned RBs November 2012 | LTE Introduction | 208
  • 209. Resource allocation versus time PUCCH allocation No resource scheduled PUSCH allocation, different #RB and RB offset November 2012 | LTE Introduction | 209
  • 210. LTE scheduling impact on power versus time TTI based scheduling. Different RB allocation Impact on UE power November 2012 | LTE Introduction | 210
  • 211. Transmit signal quality – carrier leakage Frequency error fc f Fc+ε Carrier leakage (The IQ origin offset) is an additive sinusoid waveform that has the same frequency as the modulated waveform carrier frequency. Parameters Relative Limit (dBc) Output power >0 dBm -25 -30 dBm ≤ Output power ≤0 dBm -20 -40 dBm  Output power < -30 dBm -10 November 2012 | LTE Introduction | 211
  • 212. Impact on Tx modulation accuracy evaluation l 3 modulation accuracy requirements l EVM for the allocated RBs l LO leakage for the centred RBs ! LO spread on all RBs l I/Q imbalance in the image RBs LO leakage level RF carrier signal I/Q imbalance noise RB0 RB1 RB2 RB3 RB4 EVM November 2012 | LTE Introduction | 212 RB5 frequency
  • 213. Inband emissions 3 types of inband emissions: general, DC and IQ image Used allocation < ½ channel bandwidth channel bandwidth November 2012 | LTE Introduction | 213
  • 214. Carrier Leakage Carrier leakage (the I/Q origin offset) is a form of interference caused by crosstalk or DC offset. It expresses itself as an un-modulated sine wave with the carrier frequency. I/Q origin offset interferes with the center sub carriers of the UE under test. The purpose of this test is to evaluate the UE transmitter to verify its modulation quality in terms of carrier leakage. DC carrier leakage due to IQ offset LO Leakage Parameters Relative Limit (dBc) Output power >0 dBm -25 -30 dBm ≤ Output power ≤0 dBm -20 -40 dBm  Output power < -30 dBm -10 November 2012 | LTE Introduction | 214
  • 215. Inband emmission – error cases November 2012 | LTE Introduction | 215 DC carrier leakage due to IQ offset
  • 216. Inband emmission – error cases Inband image due to IQ inbalance November 2012 | LTE Introduction | 216
  • 217. DC leakage and IQ imbalance in real world … November 2012 | LTE Introduction | 217
  • 218. UL Modulation quality: Constellation diagram LTE PUSCH uses QPSK, 16QAM and 64 QAM (optional) modulation schemes. In UL there is only 1 scheme allowed per subframe November 2012 | LTE Introduction | 218
  • 219. Error Vector Magnitude, EVM Q Magnitude Error (IQ error magnitude) Error Vector Measured Signal Ideal (Reference) Signal Φ Phase Error (IQ error phase) I Reference Waveform Demodulator 011001… Ideal Modulator - Input Signal Σ Difference Signal + Measured Waveform November 2012 | LTE Introduction | 219
  • 220. Error Vector Magnitude, EVM 7 symbols / slot time 0123456 0123456 0123456 0123456 PUSCH symbol frequency Demodulation Reference symbol, DMRS Limit values Unit Level QPSK % 17.5 16QAM % 12.5 64QAM % [tbd] Parameter November 2012 | LTE Introduction | 220
  • 221. Error Vector Magnitude, EVM CP center 1 SC-FDMA symbol, including Cyclic Prefix, CP OFDM Symbol Part equal to CP Cyclic prefix FFT Window size FFT window size depends on channel bandwidth and extended/normal CP length November 2012 | LTE Introduction | 221
  • 222. Cyclic prefix aspects We can observe a phase shift CP part CP OFDM symbol n-1 Content is different in each OFDM symbol CP part CP OFDM symbol n OFDM symbol is periodic! Cyclic prefix does not provoque phase shift November 2012 | LTE Introduction | 222
  • 223. Time windowing 1 SC-FDMA symbol, including Cyclic Prefix, CP 1 SC-FDMA symbol, including Cyclic Prefix, CP Cyclic prefix OFDM Symbol Cyclic Part equal prefix to CP OFDM Symbol Part equal to CP Continuous phase shift Difference in phase shift Phase shift between SC-FDMA symbols will cause side lobes in spectrum display! November 2012 | LTE Introduction | 223
  • 224. Time windowing Tx time window creates some kind of clipping in symbol transitions Tx Time window Tx Time window Cyclic prefix OFDM Symbol Cyclic Part equal prefix to CP OFDM Symbol Part equal to CP Continuous phase shift Difference in phase shift Tx time window can be used to shape the Tx spectrum in a more steep way, but …. November 2012 | LTE Introduction | 224
  • 225. Time windowing Tx time window creates some kind of clipping in symbol transitions Tx Time window Tx Time window Cyclic prefix OFDM Symbol Cyclic Part equal prefix to CP OFDM Symbol Part equal to CP Continuous phase shift Difference in phase shift Tx time window will create a higher Error Vector Magnitude! Here the Tx time window of 5µsec causes Some mismatch between the 2 EVM Measurements of the first SC-FDMA symbol November 2012 | LTE Introduction | 225
  • 226. EVM vs. subcarrier Nominal subcarriers Each subcarrier Modulated with e.g. QPSK f f0 f1 f2 f3 Error vector .... Error vector Note: simplified figure: in reality you compare the waveforms due to SC-FDMA November 2012 | LTE Introduction | 226 Integration of all Error Vectors to Display EVM curve
  • 227. EVM vs. subcarrier November 2012 | LTE Introduction | 227
  • 228. EVM Equalizer Spectrum Flatness The EVM equalizer spectrum flatness is defined as the variation in dB of the equalizer coefficients generated by the EVM measurement process. The EVM equalizer spectrum flatness requirement does not limit the correction applied to the signal in the EVM measurement process but for the EVM result to be valid, the equalizer correction that was applied must meet the EVM equalizer spectral flatness minimum requirements. Nominal subcarriers Amplitude Equalizer coefficients f f0 f1 Integration of all amplitude equalizer coefficients to display spectral flatness curve f2 f3 Subcarriers before equalization 1 | A( EC ( f )) |2 12 * N RB 12* N RB P( f )  10 * log | A( EC ( f ) |2 November 2012 | LTE Introduction | 228
  • 229. Spectrum flatness calculation 1-tap equalization = Interpreting the frequency Selectivity as scalar factor Equalizer tries to set same power level for all subcarriers A(f) 1 | A( EC ( f )) |2 12 * N RB 12* N RB P( f )  10 * log | A( EC ( f ) |2 1-tap equalization = Calculating scalar to amplify or attenuate f November 2012 | LTE Introduction | 229
  • 230. Spectral flatness November 2012 | LTE Introduction | 230
  • 231. Output RF Spectrum Emissions Out-of-band emissions occupied bandwidth Spurious Emissions Spectrum Emission Mask – SEM -> measurement point by point (RBW) Adjacent Channel Leakage Ratio – ACLR -> integration (channel bandwidth) Spurious domain ΔfOOB Channel bandwidth ΔfOOB Spurious domain RB E-UTRA Band Worst case: Resource Blocks allocated at channel edge Harmonics, parasitic emissions, intermodulation and frequency conversion from modulation process November 2012 | LTE Introduction | 231
  • 232. Adjacent Channel Leakage Ratio, ACLR Active LTE carrier, 20MHz BW 1 adjacent LTE carrier, 20MHz BW 2 adjacent WCDMA carriers, 5MHz BW November 2012 | LTE Introduction | 232
  • 233. Occupied Bandwidth - OBW Occupied bandwidth is defined as the bandwidth containing 99 % of the total integrated mean power of the transmitted spectrum 99% of mean power Channel Bandwidth [MHz] Transmission Bandwidth Configuration [RB] Channel edge Resource block Channel edge Transmission Bandwidth [RB] Active Resource Blocks DC carrier (downlink only) November 2012 | LTE Introduction | 233
  • 234. Impact on SEM limit definition Limits depend on channel bandwidth Spectrum emission limit (dBm)/ Channel bandwidth ΔfOOB (MHz) 3.0 M Hz 5 M Hz 10 M Hz 15 M Hz 20 M Hz Measurement bandwidth  0-1 -10 -13 -15 -18 -20 -21 30 kHz  1-2.5 -10 -10 -10 -10 -10 -10 1 MHz  2.5-5 Limits vary dependent on offset from assigned BW 1.4 MH z -25 -10 -10 -10 -10 -10 1 MHz -25 -13 -13 -13 -13 1 MHz -25 -13 -13 -13 1 MHz -25 -13 -13 1 MHz -25 -13 1 MHz -25 1 MHz  5-6  6-10  10-15  15-20  20-25 November 2012 | LTE Introduction | 234
  • 235. LTE Uplink: PUCCH Allocation of PUCCH only. frequency November 2012 | LTE Introduction | 235
  • 236. PUCCH measurements PUCCH is transmitted on the 2 side parts of the channel bandwidth November 2012 | LTE Introduction | 236
  • 237. LTE Receiver Measurements 1 2 3 4 4.1 4.2 4.3 5 6 6.1 7 Reference sensitivity level Maximum input level Adjacent Channel Selectivity (ACS) Blocking characteristics In-band blocking Out-of-band blocking Narrow band blocking Spurious response Intermodulation characteristics Wide band Intermodulation Spurious emissions November 2012 | LTE Introduction | 237
  • 238. RX Measurements – general setup AWGN Blockers Adjacent channels Receive Sensitivity Tests User definable DL assignment Table (TTI based) Specifies DL scheduling parameters like RB allocation Modulation, etc. for every TTI (1ms) Transmit data according to table on PDSCH Use both Rx Antennas + Receive feedback on PUSCH or PUCCH ACK/NACK/DTX Counting requirements in terms of throughput (BLER) instead of BER November 2012 | LTE Introduction | 238
  • 239. RX sensitivity level Criterion: throughput shall be > 95% of possible maximum (depend on RMC) Channel bandwidth E-UTRA Ban d 1.4 MHz (dBm) 3 MHz (dBm) 5 MHz (dBm) 10 MHz (dBm) 15 MHz (dBm) 20 MHz (dBm) 1 - - -100 -97 -95.2 -94 FDD 2 -104.2 -100.2 -98 -95 -93.2 -92 FDD 3 -103.2 -99.2 -97 -94 -92.2 -91 FDD 4 -106.2 -102.2 -100 -97 -95.2 -94 FDD 5 -104.2 -100.2 -98 -95 6 - - -100 -97 FDD FDD Extract from TS 36.521 Sensitivity depends on band, channel bandwidth and RMC under test November 2012 | LTE Introduction | Duplex Mode 239
  • 240. Block Error Ratio and Throughput Rx quality DL signal Channel setup Criterion: throughput shall be > 95% of possible maximum (depending on RMC) November 2012 | LTE Introduction | 240
  • 241. Rx measurements: BLER definition PDCCH, scheduling info Count #NACKs and calculate BLER PDSCH, as PRBS ACK/NACK feedback Assumption is that eNB Power = UE Rx power November 2012 | LTE Introduction | 241
  • 242. Details LTE FDD signaling Rx Measurements l Rx Measurements l Counting – ACKnowledgement (ACK) – NonACKnowledgement (NACK) – DTX (no answer from UE) l Calculating l l November 2012 | LTE Introduction | 242 BLER (NACK/ALL) Throughput [kbps]
  • 243. Rx measurements: BLER definition PDCCH, scheduling info PDSCH, user data •ACK = UE properly Receives PDCCH + PDSCH •NACK = UE properly receives PDCCH but does not understand PDSCH •DTX = UE does not understand PDCCH ACK/NACK feedback ACK relative = NACK relative = DTX relativ = # ACK # ACK  # NACK  # DTX BLER = # NACK # ACK  # NACK  # DTX # DTX # ACK  # NACK  # DTX November 2012 | LTE Introduction | 243 # NACK  # DTX # ACK  # NACK  # DTX
  • 244. Throughput versus SNR November 2012 | LTE Introduction | 244
  • 245. Throughput measurements Max throughput possible in SISO November 2012 | LTE Introduction | 245
  • 246. Rx measurements - throughput Throughput Measurement, Settings for max throughput for SISO: Number of Resource blocks Modulation scheme Transport block size November 2012 | LTE Introduction | 246
  • 247. Throughput + CQI in LTE Change of RF condition> lower data rate UE sends different CQI values November 2012 | LTE Introduction | 247
  • 248. MIMO in LTE: BLER and throughput November 2012 | LTE Introduction | 248
  • 249. Throughput measurements MIMO active, 2 streams with different data rate November 2012 | LTE Introduction | 249
  • 250. Why do we need fading? l 3GPP specifies various tests under conditions of fading l l l l WCDMA performance tests HSDPA performance tests LTE performance tests LTE reporting of channel state information tests See CMW capability lists for details l Evaluation of MIMO performance gain requires fading l l l Correlated transmission paths in MIMO connection Simulation of “real life conditions” in the lab Comparison of processing gain for different transmission modes November 2012 | LTE Introduction | 250
  • 251. Most popular MIMO scheme to increase data rates: Spatial Multiplexing h 11 h 12 TX Ant 1 h22 Space Matix B TX Ant 2 d1 LO d2 h 21 2X2 MIMO RX Ant 1 RX Ant 2 n1 r1 r2 MIMO RX (e.g. ZF, MMSE,MLD) Time n2 No increase of total transmit power, i.e. distribution of transmit power across multiple transmit antennas! Doubles max. data rates, however, at the expense of SNR @ receiver. Thus, according to Shannon‘s law, decrease of performance. Makes sense for low order modulation schemes only (QPSK, 16QAM), or in case of very good SNR conditions, e.g. for receivers close to base stations. November 2012 | LTE Introduction | 251 de1 de2
  • 252. Internal fading in LTE November 2012 | LTE Introduction | 252
  • 253. BLER results with and without fading November 2012 | LTE Introduction | 253
  • 254. The mobile device evolution Voice Call SMS … Voice Call SMS MMS WAP E-Mail Internet Access IPv4 ... Voice Call SMS MMS WAP E-Mail Internet Access IPv4 IPv6 VoIP (Skype) Games A-GPS ... Voice Call SMS MMS WAP E-Mail Internet Access IPv4 IPv6 VoIP (Skype) Games Video Call A-GPS/SUPL2.0 IMS support SMS over IMS Voice/Video over IMS CSFB ... 2G GSM 2.5G/2.75G GPRS/EDGE 3G/3.5G UMTS/HSPA 3.9G/4G LTE/LTE-A/HSPA-DC November 2012 | LTE Introduction | 254
  • 255. Why End-to-End testing? Voice Call SMS MMS WAP E-Mail Internet Access IPv4 IPv6 VoIP (Skype) Games Video Call A-GPS/SUPL2.0 IMS support SMS over IMS Voice/Video over IMS CSFB ... Smartphone All features on a phone have an direct impact on the battery life of the phone and it’s power consumption, but also on the generated traffic by the phone. Keywords: lHW and SW of a phone need to be designed in an efficient way for a long battery life lHW and SW need to be designed in a way, that they provide the service reliable lEfficient application desig for low IP traffic ... Focus: lValidation of HW and SW in combination l Simulation of end-user scenarios in an isolated and controlled environment l Validation of applications with repeatable and comparable results … That‘s why End-to-End test! November 2012 | LTE Introduction | 255
  • 256. Here it is! The „Data Application Unit“! Embedded PC based on Linux! November 2012 | LTE Introduction | 256
  • 257. CMW DAU - Main Features 1. Easy Data Testing IP configuration l Ready to use Standalone IP configuration for the CMW l Easy Company LAN integration (DHCPv4, static IP addresses) l Data continuity during Handover between RATs l Remote control by MLAPI & SCPI 2. DAU IP services (Applications) l Provides R&S throughput optimized data applications (ftp, http, …) l New features like IMS (for VoLTE or SMS over IMS) l Provides storage for media files (own Hard Disk) 3. Closed environment l guaranties repeatable and comparable test results November 2012 | LTE Introduction | 257
  • 258. DAU User Interface on the CMW l Data Application Control (DAC) l l l Accessible via Setup-> System -> DAU -> Go to Config Data Testing IP configuration Start/Stop, Configure global servers like FTP, HTTP November 2012 | LTE Introduction | 258
  • 259. DAU User Interface on the CMW l Data Application Measurements (DAM) l l Accessible over the CMW Measurements Provides User Interface for – Applications: start Iperf, trigger Ping, send/receive eMails … – Measurements: Throughput, Traffic statistics Go to DAC November 2012 | LTE Introduction | 259
  • 260. Feature Set FW2.1.26 Latency Throughput Overall measurements Indication IPERF Throughput Measurement November 2012 | LTE Introduction | 260
  • 261. Throughput end to end November 2012 | LTE Introduction | 261
  • 262. End to end testing – ping response, RTT November 2012 | LTE Introduction | 262
  • 263. Integrated Servers FW2.1.26 November 2012 | LTE Introduction | 263
  • 264. Introduction IMS – IP Multimedia Subsystem Definition l IMS (IP multimedia subsystem) itself is not a technology, it is an architecture l IMS is an all-IP service layer between transport and application layer based on common Internet protocols l IMS architecture enables the connection to networks using multiple mobile and fixed devices and technologies l IMS defines an architecture for the convergence of audio, video and data to enable integrated Multimedia Sessions over fixed and wireless networks l The long-term solution for supporting voice services in LTE will be based on the IMS (IP Multimedia Subsystem) framework. November 2012 | LTE Introduction | 264
  • 265. Introduction IMS – IP Multimedia Subsystem Definition Services: l SMS over IMS Voice over IMS Video over IMS TBD IMS is a global access-independent and standard-based IP connectivity and service control architecture that enables various types of multimedia services to end-users using common Internet-based protocols. November 2012 | LTE Introduction | 265
  • 266. 3 GPP System Architecture Evolution Signaling interfaces Data transport interfaces RAN Access PDN directly or via IMS MME UE PDN Evolved nodeB S-GW P-GW IMS PSTN Evolved Packet Core external IMS to control access + data transfer All interfaces are packet switched November 2012 | LTE Introduction | 266
  • 267. IMS Architecture November 2012 | LTE Introduction | 267
  • 268. IMS protocol structure user plane Control plane SIP/SDP Voice video RTP IKE messaging MSRP UDP / TCP / SCTP IP / IP sec Layer 3 control Layer 1/2 Layer 1/2 Mobile com specific protocols (other IP CAN) IMS specific protocols November 2012 | LTE Introduction | 269
  • 269. IMS Registration and Authentication Comparison with LTE LTE IMS ATTACH REQUEST REGISTER AUTHENTICATION REQ 401 UNAUTHORIZED AUTHENTICATION RSP REGISTER ATTACH ACCEPT November 2012 | LTE Introduction | 200 OK 270
  • 270. l How to connect E-UTRAN to CS services? Connection via IMS: 3GPP and OneVoice initiative First a big mess, Now it seems to be OneVoice l Voice over LTE Generic Access – VoLGA Forum – interim solution l CS Fallback CSFB for voice calls to 2G or 3G services – preferred interim solution l Evolved MSC, eMSC – CS Services via EPS – network operator proposal, interim solution l SRVCC – Single Radio Voice Call Continuity l SV-LTE – simultaneous voice and LTE l OTT, Over the top – propietary solution, application based November 2012 | LTE Introduction | 271
  • 271. Voice over IMS: IMS protocol profile Adaptive Multirate Codecs are used In VoIP over IMS Codec mode AMR_12.20 AMR_10.20 Source codec bit-rate 12,20 kbit/s (GSM EFR) 10,20 kbit/s AMR_7.95 7,95 kbit/s AMR_7.40 7,40 kbit/s (IS-641) AMR_6.70 6,70 kbit/s (PDC-EFR) AMR_5.90 5,90 kbit/s AMR_5.15 5,15 kbit/s AMR_4.75 4,75 kbit/s AMR_SID 1,80 kbit/s (see note 1) November 2012 | LTE Introduction | 272
  • 272. QoS class identifiers QCI QCI Priority Packet Delay Budget Packet Error Loss Rate 1 2 100 ms 10-2 Conversational Voice 2 4 150 ms 10-3 Conversational Video (Live Streaming) 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 3 Resource Type GBR 6 6 300 ms 7 7 100 ms 8 8 9 9 10-6 Non-GBR Example Services Video (Buffered Streaming) TCP-based (e.g. www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.) 10-3 Voice, Video (Live Streaming), Interactive Gaming 10-6 Video (Buffered Streaming) TCP-based (e.g. www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.) 300 ms November 2012 | LTE Introduction | 273
  • 273. Voice over LTE – protocol profiles AMR codec Optimize transmission of Voice by configuring Lower layers Use robust header compression or IP Short PDCP header is used Use RLC in UM mode Small sequence number is used SRB1 and 2 are supported for DCCH + one UM DRB with QCI 1 for voice for SIP signaling + one AM DRB QCI 5 for SIP signaling + one AM DRB QCI 8 for IMS traffic TTI bundling + DRX to reduce PDCCH Signaling + Semi-persistend scheduling UDP/ TCP IP Packet Data Convergence PDCP Radio Link Control RLC Medium Access Control MAC PHYSICAL LAYER November 2012 | LTE Introduction | 274
  • 274. CMW500 Data Application Unit Integrated IMS Server IMS Configuration IMS infoscreen Mobile infoscreen November 2012 | LTE Introduction | 275
  • 275. IP Based communication client - Source - Destination Routing decision based on: - load - cost of routing - broken links Cause in: - packet delay - jitter - losses server November 2012 | LTE Introduction | 276
  • 276. CMW500 Data Application Unit Network Impairment Emulate characteristics of a real network Impairments: l l l l l Delay Jitter Packet Loss Packet Corruption Packet Duplication Packet Re-ordering DAU Application Delay FTP PING HTTP IPERF LANDAU l TUN l Loss NOTE: Network Impairment are available for DL traffic November 2012 | LTE Introduction | 277
  • 277. CMW500 Data Application Unit Network Impairment l l UP to 7 different Impairment per DAM possible Impairments are identified by a filter rule l l l l IPv4 address filter IPv6 address/prefix filter Additionally a optional TCP/UDP Port filter Feedback provided when error occur November 2012 | LTE Introduction | 278
  • 278. Voice over LTE (VoLTE) testing R&S solutions - Overview  LTE attach procedure  IMS registration Audio: echo verification in loopback mode IP Traffic Logging Impact of noise, IP traffic impairment  LTE attach procedure  IMS Terminal Testing  Session Initiation Protocol (SIP)  Conformance Testing  Audio: echo verification in loopback mode R&S®CMW500 LTE Protocol Tester R&S®CMW500 LTE Call-box Functional testing Audio Quality testing R&S®UPV Audio Analyzer R&S®CMW-PQA  Verify audio quality using PESQ®  and POLQA® algorithm  Acoustic analysis: 3GPP TS 26.132 Performance testing  Automated test of impacts of noise, fading, IP traffic impairment… with R&S Contest November 2012 | LTE Introduction | 279
  • 279. LTE CallBox used for VoLTE Audio Quality Testing Scope of Audio Quality testing lAnalysis of the Audio Quality l„What is the Audio Quality of the VoLTE call a UE Functional testing Audio Quality testing can perform?“ lVerification of the audio quality with established mechanisms like PESQ® and POLQA® algorithm lAcoustic analysis of the signal according to 3GPP TS 26.132 Release 10 R&S®CMW500 LTE Call-box Performance testing November 2012 | LTE Introduction | R&S®UPV Audio Analyzer 280
  • 280. NEW DAU Features Useful in LTE Integrated IMS Server for Voice over IMS IMS Configuration Features: lLoopback mode or MediaEndpoint Connection for separate DL/UL Analysis lNarrowband lWideband lDifferent Codec Rates lUseCase: IMS infoscreen Mobile infoscreen l November 2012 | LTE Introduction | 281 VoLTE or VoHSPA
  • 281. CMW500 Speech Verification Audio Quality analysis - Uplink l l IMS server Media Server* RF to microphone USB Connection l CMW500 establishes LTE and IMS connection to UE Uplink verification: PESQ/POLQA sequence from UPV is provided to UE and sent in uplink to CMW500; received VoIP data is converted to analog (USB soundcard) and analyzed in UPV Test focus: l l PESQ/POLQA analysis *Media Server functionality: l De-packaging speech data from RTP l De-Coding digital speech data (e.g. AMR WB) November 2012 | LTE Introduction | 282 UPV analyzes the audio quality PESQ/POLQA Verification of separated uplink
  • 282. CMW500 Speech Verification Acoustic tests according to 3GPP TS 26.132 l l IMS server Media Server* RF to microphone LAN Connection 3GPP TS26.132 analysis from loudspeaker l USB Connection *Media Server functionality: l De-packaging speech data from RTP l De-Coding digital speech data (e.g. AMR WB) November 2012 | LTE Introduction | 283 CMW500 establishes LTE and IMS connection to UE DL or UL verification: 3GGP defined tests performed by UPV using an artificial head Test focus: l l Acoustic tests according to 3GPP TS 26.132 Verification of uplink and downlink
  • 283. Final Test Setup for VoLTE Acoustic measurements Integrated IMS, integrated Audio Board and Codecs Integrated Audioboard l CMW500 establishes LTE and IMS connection to UE l establish a VoLTE call by using internal audio board and codecs l Test focus: RF IMS server Audio Codecs to microphone From loudspeaker l l DL UL PESQ/POLQA analysis November 2012 | LTE Introduction | 284 Audio Quality Analysis PESQ/POLQA Acoustic tests according to 3GPP TS 26.132 with artificial head
  • 284. Feature overview with 3.0.20 l l l l l l l Support of different RATs Server for FTP, HTTP, IMS and DNS IP Impairments IP Logging IMS Services SMS and VoIP PING Latency IPERF DNS FTP Application HTTP VIDEO Call VoIP Call SMS IPERF TP Streaming PING Latency IMS Data Application Unit IP-Logging IP RAT IP-Impairments LTE-FDD 1xEV-DO WLAN November 2012 | LTE Introduction | 285 LTE-TDD GSM WCDMA
  • 285. Radio Access Technologies today CDMA2K 1xEVDO GERAN UTRAN EUTRAN LTE coverage is not fully up from day one -> interworking with legacy networks is essential!!! November 2012 | LTE Introduction | 286
  • 286. Voice calls in LTE l There is one common solution: Voice over IMS l -> also named Voice over LTE VoLTE or OneVoice initiative But…. What if IMS is not available at first rollout? -> interim solution called Circuit Switched Fallback CSFB = handover to 2G/3G -> or Simultaneous Voice on 1XRTT and LTE, SV-LTE = dual receiver What is if LTE has no full coverage? -> interworking with existing technologies, Single Radio Voice Call Continuity, SRVCC November 2012 | LTE Introduction | 287
  • 287. 2G or 3G CS fallback Voice call E-UTRAN MME IMS Voice over IMS is the solution, but IMS is maybe not available in the first network roll-out. Need for transition solution: Circuit Switched Fall Back, CSFB move the call to 2G or 3G November 2012 | LTE Introduction | 288
  • 288. CSFB issues and questions UTRAN Target cell assigned or selected by UE? Uu Iu-ps SGSN Gs Gb GERAN S3 Um UE LTE Uu Iu-cs MSC Server A E-UTRAN S1-MME SGs MME Handover or Redirection? •Is it a handover command or a command to redirect to a new RAN ? i.e. the UE selects the target cell or the EUTRAN commands the target cell •Is there any information about the target RAN available (SysInfo)? •Is there a packet data connection PDN active or not? •Will the PDN be suspended or continued in the target RAN? •Will the UE re-initiate the PDN or continue? November 2012 | LTE Introduction | 289
  • 289. CS fallback options to UTRAN and GERAN Feature group index, UE indicates CSFB support November 2012 | LTE Introduction | 290
  • 290. CS fallback to 1xRTT 1xCS CSFB UE 1xRTT CS Access 1xRTT MSC A1 A1 Tunneling of messages between 1xRTT MSC and UE 1xCS IWS S102 MME S1-MME 1xCS CSFB UE S11 Serving/PDN GW E-UTRAN S1-U Tunnelled 1xRTT messages November 2012 | LTE Introduction | 291 S102 is the reference point between MME and 1xCS interworking solution SGi
  • 291. CS fallback to 1xRTT November 2012 | LTE Introduction | 292
  • 292. CS fallback - arguments l E-UTRAN and GERAN/UTRAN coverage must overlap l No E-UTRAN usage for voice l No changes on EPS network required l Gs interface MSC-SGSN not widely implemented l Increased call setup time l No simultaneous voice + data if 2G network/UE does not support DTM l SMS can be used without CS fallback, via E-UTRAN November 2012 | LTE Introduction | 293
  • 293. Why not CSFB? l Call setup delay l Call drop due to handover l Blind hand-over is used for CSFB l Data applications are interupted l Legacy RAN coverage needed November 2012 | LTE Introduction | 294
  • 294. Dual receiver 1xCSFB UE Circuit switched 1xRTT registration CDMA2000 cell eNB for LTE Packet switched EUTRAN registration Dual receiver 1xCSFB UEs can handle separate mobility and registration procedures 2 radio links at the same time. UE is registered to 2 networks, no coordination required. When CS connection in 1xRTT, dual receiver UE leaves EUTRAN! November 2012 | LTE Introduction | 295
  • 295. SV-LTE: Simultaneous CDMA200 + LTE UE Circuit switched 1xRTT connection CDMA2000 cell eNB for LTE Packet switched EUTRAN connection Simultaneous Voice UEs can handle 2 radio links at the same time. UE is registered to MME and CDMA2K independently November 2012 | LTE Introduction | 296
  • 296. OTT – over the top EUTRAN Application UE Evolved nodeB S-GW P-GW PDN Evolved Packet Core Voice call as application, e.g. Skype, Google talk, … November 2012 | LTE Introduction | 297
  • 297. OTT – over the top - arguments EUTRAN UE Application Evolved nodeB S-GW P-GW PDN Evolved Packet Core •Propietary solution, needs to be implemented in UE and AS •Already implemented in computer networks – known application •Support has to be accepted by operator •No Inter-RAT handover is possible November 2012 | LTE Introduction | 298
  • 298. SMS transfer in LTE Encapsulate SMS in NAS Control message-> SMS over SG EMM Send SMS over IMS Using IP protocol SMS over IMS ESM User plane Radio Resource Control RRC Control & Measurements Packet Data Convergence PDCP Radio Bearer Radio Link Control RLC Logical channels Medium Access Control MAC Transport channels PHYSICAL LAYER November 2012 | LTE Introduction | 299
  • 299. Single Radio Voice Call Continuity Problem: in first network roll-out, there is no full LTE coverage. How to keep call active? => SRVCC November 2012 | LTE Introduction | 300
  • 300. Single Radio Voice Call Continuity VoLTE call eNodeB = EUTRAN Handover to UTRAN VoIP in PS mode NodeB = UTRAN Radio Bearer reconfiguration: PS to CS mode time NodeB = UTRAN Voice call in CS mode November 2012 | LTE Introduction | 301
  • 301. Handover – what to discuss? UE reads SysInfo GERAN cell(s)? eNodeB EUTRAN cell UTRAN cell(s)? CDMA2K cell(s)? UE Will the UE initiate the change? -> re-selection Will the network initiate the change? -> redirection or handover NW sends Redirection command? SysInfo of Target? Handover command? November 2012 | LTE Introduction | Mandatory for UE supporting CSFB 302
  • 302. Handover aspects – what to discuss? l Some keywords that appear – and to be clarified in next slides: l Handover? Cell reselection? Cell change order? Redirection? Network assisted cell change, NACC? Circuit switched fallback, CS fallback? l l l l l November 2012 | LTE Introduction | 303
  • 303. Mobility between LTE and WCDMA/GSM Radio Access Aspects GSM_Connected CELL_DCH Handover E-UTRA RRC_CONNECTED Handover GPRS Packet transfer mode CELL_FACH CELL_PCH URA_PCH CCO with optional NACC Reselection Connection establishment/release Connection establishment/release UTRA_Idle CCO, Reselection Reselection E-UTRA RRC_IDLE Connection establishment/release Reselection CCO, Reselection November 2012 | LTE Introduction | 304 GSM_Idle/GPRS Packet_Idle
  • 304. Redirection to UMTS UE reads SysInfo eNodeB EUTRAN cell NodeB(s) UTRAN cell(s) UE will search for suitable cell on UARFCN and initiate CS connection UE RRC connection release message with RedirectedCarrierInfo to UTRAN Mandatory for UE supporting CSFB RRC connection release with redirection without SysInfo November 2012 | LTE Introduction | 305
  • 305. Redirection to UMTS Rel. 9 feature UE reads SysInfo NodeB UTRAN cell UE will go to indicated cell and initiate CS connection Sys Info UE eNodeB EUTRAN cell RRC connection release message with RedirectedCarrierInfo to UTRAN e-RedirectionUTRA capability is set by UE RRC connection release with redirection with SysInfo November 2012 | LTE Introduction | 306
  • 306. Redirection to GERAN eNodeB EUTRAN cell BTS(s) GSM cell(s) UE will search for suitable cell on ARFCN and initiate CS connection UE RRC connection release message with RedirectedCarrierInfo to GSM Mandatory for UE supporting CSFB RRC connection release with redirection without SysInfo November 2012 | LTE Introduction | 307
  • 307. Redirection to GERAN Rel. 9 feature BTS(s) GSM cell(s) UE will go to indicated cell and initiate CS connection Sys Info UE eNodeB EUTRAN cell RRC connection release message with RedirectedCarrierInfo to GSM e-RedirectionUTRA capability is set by UE RRC connection release with redirection with SysInfo November 2012 | LTE Introduction | 308
  • 308. Handover to UMTS: Packet switched handover eNodeB EUTRAN cell NodeB(s) UTRAN cell(s) UE UE will select target cell on UARFCN and continue PS connection MobilityFromEUTRACommand message with purpose indicator = handover to UTRAN EUTRAN contains targetRATmessagecontainer, = Inter-RAT info about target cell Packet Switched handover to UTRAN November 2012 | LTE Introduction | 309
  • 309. Inter-RAT Handover to GERAN: cell change order PS connection will be suspended eNodeB EUTRAN cell BTS(s) GPRS cell(s) UE will search for suitable cell on ARFCN and re-initiate PS connection UE MobilityFromEUTRACommand message with purpose indicator = Cell Change Order to GPRS Mandatory for UE supporting CSFB Packet Switched cell change order to GPRS without NACC (network assisted cell change) November 2012 | LTE Introduction | 310
  • 310. Inter-RAT Handover to GERAN: cell change order PS connection will be suspended BTS GPRS cell UE will search for suitable cell on ARFCN and initiate PS connection Sys Info UE eNodeB EUTRAN cell MobilityFromEUTRACommand message with purpose indicator = Cell Change Order to GPRS Mandatory for UE supporting CSFB Packet Switched cell change order to GPRS with NACC (network assisted cell change) November 2012 | LTE Introduction | 311
  • 311. Inter-RAT Handover to GERAN: handover PS connection will be handed over eNodeB EUTRAN cell BTS GPRS cell UE will search for suitable cell on ARFCN and continue PS connection UE MobilityFromEUTRACommand message with purpose indicator = handover to GPRS Mandatory for UE supporting CSFB Packet Switched handover to GPRS November 2012 | LTE Introduction | 312
  • 312. LTE-RTT Handover Circuit Switched Fallback, CSFB Overview November 2012 | LTE Introduction | 313
  • 313. CS fallback to 1xRTT 1xCS CSFB UE 1xRTT CS Access 1xRTT MSC A1 A1 Tunneling of messages between 1xRTT MSC and UE 1xCS IWS S102 MME S1-MME 1xCS CSFB UE S11 Serving/PDN GW E-UTRAN S1-U Tunnelled 1xRTT messages November 2012 | LTE Introduction | 314 S102 is the reference point between MME and 1xCS interworking solution SGi
  • 314. CS fallback to 1xRTT CSFB to 1xRTT MME CSFB Info eNodeB EUTRAN cell 1xRTT cell(s) UE will search for suitable cell on UARFCN and initiate CS connection UE RRC connection release message with RedirectedCarrierInfo to Mandatory 1xRTT for UE Enhancement: UE can pre-register in 1xRTT network supporting CSFB to 1xRTT RRC connection release with redirection without SysInfo November 2012 | LTE Introduction | 315
  • 315. CS fallback to 1xRTT enhanced 1xCSFB (e1xCSFB) Enhancement: UE can pre-register in 1xRTT network UE 1) Prepare for handover, search for 1xRTT EUTRAN HandoverFromEUTRAPreparationRequest UE 2) Info about 1xRTT -> tunnelled via S102 EUTRAN ULHandoverPreparationTransfer UE 3) Includes 1xRTT channel assignment EUTRAN MobilityFromEUTRACommand November 2012 | LTE Introduction | 316 Time flow
  • 316. CS fallback to 1xRTT enhanced 1xCSFB (e1xCSFB) + concurrent HRPD handover Enhancement: UE can pre-register in 1xRTT network 1) Prepare for handover, search for 1xRTT + HRPD UE EUTRAN HandoverFromEUTRAPreparationRequest 2) Trigger 2 messages with info about 1xRTT + HRPD UE EUTRAN ULHandoverPreparationTransfer UE EUTRAN ULHandoverPreparationTransfer UE 3) Redirection to 1xRTT and handover to HRPD EUTRAN MobilityFromEUTRACommand November 2012 | LTE Introduction | 317 Time flow
  • 317. LTE-eHRPD Handover Overview November 2012 | LTE Introduction | 318
  • 318. EUTRAN – eHRPD non-roaming i.e. US subscriber, connected To home network, leaves LTE coverage area November 2012 | LTE Introduction | 319
  • 319. EUTRAN – eHRPD, roaming case i.e. European subscriber visiting US, connected to roaming network and leaving LTE coverage area November 2012 | LTE Introduction | 320
  • 320. Mobility between LTE and HRPD Radio Access Aspects No handover to EUTRAN HRPD active to EUTRAN is always cell reselection (via RRC idle) November 2012 | LTE Introduction | 321
  • 321. 3 Step Procedure E-UTRAN needs to decide, that HO to HRPD is required Ability of preregistration is indicated on PBCCH UE attached to E-UTRAN Pre-registration HO preparation HO execution • Reduces time for cell re-selection or handover • Reduces risk of radio link failure Traffic Channel Assignment command is delivered to UE, re-tune radio to HRPD channel, acquire HRPD channel, session configuration Connection Request issued by UE to HRPD, HRPD prepares for the arrival of the UE November 2012 | LTE Introduction | 322
  • 322. Video over LTE Testing the next step in the end user experience
  • 323. Introduction Network view Impact due to EPC / IMS l Packet delay l Packet jitter l Packet loss MME PCRF l … Node B SGW Impact due to PGW Internet l Multipath propagation l Speed l … Node B November 2012 | LTE Introduction | 324
  • 324. Introduction Testing real life conditions in the lab l Main use cases from a test engineer (operator, manufacturer) perspective: l l l Exploring the performance of mobile equipment from the end user perspective Measuring E2E throughput with realistic radio conditions Evaluating mobility performance R&S®AMU200 baseband fader simulates real life radio conditions R&S®CMW500 emulates LTE network l CMW-PQA Important aspect for end user perspective: Error free video reception November 2012 | LTE Introduction | 325 Contest SW provides automation and reporting capabilities
  • 325. Video transmission over LTE The video processing chain and possible sources for video degradation • Encoding artifacts (blocking) Impairments on the transmission link can cause loss of information despite active error correction • Video / audio delay • Buffer rules are violated The decoder is usually the less critical component. But in conjunction with the video processor, errors during the conversion process (e.g. deinterlacing) are possible Transmission link (IP, cellular, broadcast, etc.) Encoder TX RX Decoder Receiver Uncompressed video SDI SMPTE249/292/424 Video processor Redundant information (static image parts) and irrelevant data (details) is omitted Restoring the video Scaling and information; i.e. the conversion to output picture sequence format including redundant data November 2012 | LTE Introduction | 326 Output on screen
  • 326. Video transmission over LTE Testing real life conditions in the lab PC Contest TC Control RF Video via MHL or HDMI November 2012 | LTE Introduction | 327
  • 327. Video transmission over LTE R&S®VTE Video Tester l l l l l l Source, sink and dongle testing on MHL 1.2 interfaces and in the future also HDMI 1.4c, etc. Realtime difference picture analysis for testing video transmissions over LTE Combined protocol testing and audio/video analysis Future-ready, modular platform accommodating up to three test modules Localized touchscreen user interface Integrated test automation and report generation November 2012 | LTE Introduction | R&S®VTE Video Tester 328
  • 328. Summary l l Video and voice are important services gaining momentum for the fastest developing radio access technology ever - LTE Beside LTE functionality, testing voice/video quality is essential to judge a good receiver implementation l R&S provides you with profound expertise and test solutions on both aspects l Complete LTE test portfolio ranging from early R&D via IOT and field testing until conformance and production l Supplier of a complete range of TV broadcasting transmission, monitoring and measurement equipment November 2012 | LTE Introduction | 329
  • 329. There will be enough topics for future trainings  Thank you for your attention! Comments and questions welcome! November 2012 | LTE Introduction | 330