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LTE Evolution: From Release 8 to Release 10

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This seminar will provide the basics of this fascinating technology. After attending this seminar you will understand OFDM-principles, …

This seminar will provide the basics of this fascinating technology. After attending this seminar you will understand OFDM-principles,
including SC-FDMA as the transmission scheme of choice for the LTE uplink. Multiple antenna technology (MIMO) is a fundamental
part of LTE and its impact on the design of device and network architecture will be explained. Further LTE-related physical layer
aspects such as channel structure and cell search will be presented with an overview of the LTE protocol structure.
The second part of the seminar provides an overview of the evolution in LTE towards 3GPP specification Release 9 and 10. This
includes features and methods for location based services like GNSS support or time delay measurements and the concept of
multimedia broadcast. Finally, we’ll introduce the main features of LTE-Advanced (3GPP Release-10) including carrier aggregation for
a larger bandwidth and backbone network aspects like self-organizing networks and relaying concepts.

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  • 1. UMTS Long Term Evolution(LTE)Reiner StuhlfauthReiner.Stuhlfauth@rohde-schwarz.comTraining CentreRohde & Schwarz, GermanySubject to change – Data without tolerance limits is not binding.R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarksof 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 firstbe obtained in writing fromROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany
  • 2. Technology evolution path 2005/2006 2007/2008 2009/2010 2011/2012 2013/2014GSM/ EDGE, 200 kHz EDGEevo VAMOS DL: 473 kbps DL: 1.9 Mbps Double SpeechGPRS UL: 473 kbps UL: 947 kbps Capacity UMTS HSDPA, 5 MHz HSPA+, R7 HSPA+, R8 HSPA+, R9 HSPA+, R10 DL: 2.0 Mbps DL: 14.4 Mbps DL: 28.0 Mbps DL: 42.0 Mbps DL: 84 Mbps DL: 84 Mbps UL: 2.0 Mbps UL: 2.0 Mbps UL: 11.5 Mbps UL: 11.5 Mbps UL: 23 Mbps UL: 23 Mbps HSPA, 5 MHz DL: 14.4 Mbps UL: 5.76 Mbps LTE (4x4), R8+R9, 20MHz LTE-Advanced R10 DL: 300 Mbps DL: 1 Gbps (low mobility) UL: 75 Mbps UL: 500 Mbps 1xEV-DO, Rev. 0 1xEV-DO, Rev. A 1xEV-DO, Rev. B cdma DO-Advanced 1.25 MHz 1.25 MHz 5.0 MHz DL: 32 Mbps and beyond 2000 DL: 2.4 Mbps DL: 3.1 Mbps DL: 14.7 Mbps UL: 12.4 Mbps and beyond UL: 153 kbps UL: 1.8 Mbps UL: 4.9 Mbps Fixed WiMAX Mobile WiMAX, 802.16e Advanced Mobile scalable bandwidth Up to 20 MHz WiMAX, 802.16m 1.25 … 28 MHz DL: 75 Mbps (2x2) DL: up to 1 Gbps (low mobility) typical up to 15 Mbps UL: 28 Mbps (1x2) UL: up to 100 Mbps November 2012 | LTE Introduction | 2
  • 3. 3GPP work plan GERAN EUTRAN New RAN Phase 1Phase 2, 2+ UTRAN Rel. 95 … Rel. 97 Rel.7 Rel. 99 Up from Rel. 8 … Rel. 7 Rel. 9 Also contained in Rel. 10 Evolution November 2012 | LTE Introduction | 3
  • 4. Overview 3GPP UMTS evolution HSDPA/ LTE and LTE- WCDMA WCDMA HSPA+ HSUPA HSPA+ advanced 3GPP 3GPP Study 3GPP release 3GPP Release 99/4 3GPP Release 5/6 3GPP Release 7 3GPP Release 8 Item initiated Release 10 App. year of 2005/6 (HSDPA)network rollout 2003/4 2008/2009 2010 2007/8 (HSUPA) Downlink LTE: 150 Mbps* (peak) 100 Mbps high mobility 384 kbps (typ.) 384 kbps (typ.) 14 Mbps (peak) 28 Mbps (peak) HSPA+: 42 Mbps (peak) 28 Mbps (peak) data rate 1 Gbps low mobility Uplink LTE: 75 Mbps (peak) 128 kbps (typ.) 128 kbps (typ.) 5.7 Mbps (peak) 11 Mbps (peak) HSPA+: 11 Mbps (peak) 11 Mbps (peak) data rate Round Trip Time ~ 150 ms < 100 ms < 50 ms LTE: ~10 ms *based on 2x2 MIMO and 20 MHz operation November 2012 | LTE Introduction | 4
  • 5. 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 | 5
  • 6. Peak data rates and real average throughput (UL) 100 58 11,5 15 10 5,76Data rate in Mbps 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 EDGE 1xRTT WCDMA E-EDGE 1xEV-DO 1xEV-DO HSPA HSPA+ LTE 2x2 (Rel. 97) (Rel. 4) (Rel. 99/4) (Rel. 7) Rev. 0 Rev. A (Rel. 5/6) (Rel. 7) (Rel. 8) Technology max. peak UL data rate [Mbps] max. avg. UL throughput [Mbps] November 2012 | LTE Introduction | 6
  • 7. Comparison of network latency by technology 800 158 160 710 700 140 600 120 3G / 3.5G / 3.9G latency2G / 2.5G latency 500 100 85 400 80 320 70 300 60 46 190 200 40 100 20 30 0 0 GPRS EDGE WCDMA HSDPA HSUPA E-EDGE HSPA+ LTE (Rel. 97) (Rel. 4) (Rel. 99/4) (Rel. 5) (Rel. 6) (Rel. 7) (Rel. 7) (Rel. 8) Technology Total UE Air interface Node B Iub RNC Iu + core Internet November 2012 | LTE Introduction | 7
  • 8. Round Trip Time, RTT •ACK/NACK generation in RNC MSC TTI Iub/Iur Iu ~10msec Serving SGSN RNC Node B TTI =1msec MME/SAE Gateway eNode B •ACK/NACK generation in node B November 2012 | LTE Introduction | 8
  • 9. Major technical challenges in LTE New radio transmission FDD and schemes (OFDMA / SC-FDMA) TDD mode MIMO multiple antenna Throughput / data rate schemes requirements Timing requirements Multi-RAT requirements (1 ms transm.time interval) (GSM/EDGE, UMTS, CDMA) Scheduling (shared channels, System Architecture HARQ, adaptive modulation) Evolution (SAE) November 2012 | LTE Introduction | 9
  • 10. Introduction to UMTS LTE: Key parametersFrequency UMTS FDD bands and UMTS TDD bandsRange 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz Channel bandwidth, 1 Resource 6 15 25 50 75 100 Block=180 kHz Resource Resource Resource Resource Resource Resource Blocks Blocks Blocks Blocks Blocks BlocksModulation Downlink: QPSK, 16QAM, 64QAMSchemes Uplink: QPSK, 16QAM, 64QAM (optional for handset) Downlink: OFDMA (Orthogonal Frequency Division Multiple Access)Multiple Access Uplink: SC-FDMA (Single Carrier Frequency Division Multiple Access) Downlink: Wide choice of MIMO configuration options for transmit diversity, spatialMIMO multiplexing, and cyclic delay diversity (max. 4 antennas at base station and handset)technology Uplink: Multi user collaborative MIMO Downlink: 150 Mbps (UE category 4, 2x2 MIMO, 20 MHz)Peak Data Rate 300 Mbps (UE category 5, 4x4 MIMO, 20 MHz) Uplink: 75 Mbps (20 MHz) November 2012 | LTE Introduction | 10
  • 11. LTE/LTE-A Frequency Bands (FDD) E-UTRA Uplink (UL) operating band Downlink (DL) operating band Operating BS receive UE transmit BS transmit UE receive Duplex Mode Band FUL_low – FUL_high FDL_low – FDL_high 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 | 11
  • 12. LTE/LTE-A Frequency Bands (TDD) Uplink (UL) operating band Downlink (DL) operating band E-UTRA BS receive UE transmit BS transmit UE receive Operating Duplex Mode Band FUL_low – FUL_high FDL_low – FDL_high 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 3400 MHz – 3400 MHz – 41 TDD 3600MHz 3600MHz November 2012 | LTE Introduction | 12
  • 13. Orthogonal Frequency Division Multiple Accessl 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 | 13
  • 14. 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 MPPTime variant channel Doppler effectFrequency selectivity attenuation November 2012 | LTE Introduction | 14
  • 15. Still the same “mobile” radio problem:Time variant multipath propagation A: free space A: free space B: reflection B: reflection C C: diffraction C: diffraction A D: scattering D: scattering D B Transmitter ReceiverMultipath Propagation reflection: object is largeand Doppler shift compared to wavelength scattering: object is small or its surface irregular November 2012 | LTE Introduction | 15
  • 16. Multipath channel impulse responseThe CIR consists of L resolvable propagation paths L 1 h  , t    ai  t  e     i  ji  t  i 0 path attenuation path phase path delay |h|²  delay spread November 2012 | LTE Introduction | 16
  • 17. Radio Channel – different aspects to discuss Bandwidth or Wideband Narrowband Symbol duration or t t Short symbol Long symbol duration durationChannel estimation: Frequency?Pilot mapping Time? frequency distance of pilots? Repetition rate of pilots? November 2012 | LTE Introduction | 17
  • 18. Frequency selectivity - Coherence Bandwidth Here: substitute with single power Scalar factor = 1-tap Frequency selectivity How to combat channel influence? f Narrowband = equalizer Can be 1 - tap Wideband = equalizerHere: find Must be frequency selectiveMath. Equationfor this curve November 2012 | LTE Introduction | 18
  • 19. Time-Invariant Channel: Scenario Fixed ScattererISI: Inter Symbol Interference: Happens, when Delay spread > Symbol time Successive Fixed Receiver symbols Transmitter will interfere Channel Impulse Response, CIR Transmitter Receiver collision Signal Signal t t Delay Delay spread →time dispersive November 2012 | LTE Introduction | 19
  • 20. Motivation: Single Carrier versus Multi Carrier TSC |H(f)| f Source: Kammeyer; Nachrichtenübertragung; 3. Auflage 1 B TSC B 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 | 20
  • 21. Motivation: Single Carrier versus Multi Carrier TSC |H(f)| f Source: Kammeyer; Nachrichtenübertragung; 3. Auflage 1 B B TSC t |h(t)| f t |H(f)| B 1 f   B N TMC t TMC  N  TSC November 2012 | LTE Introduction | 21
  • 22. What is OFDM? Single carrier transmission, e.g. WCDMA Broadband, e.g. 5MHz for WCDMAOrthogonalFrequencyDivisionMultiplex Several 100 subcarriers, with x kHz spacing November 2012 | LTE Introduction | 22
  • 23. Idea: Wide/Narrow band conversion ƒ … S/P … …H(ƒ) t / Tb t / Ts h(τ) h(τ) „Channel Memory“ τ τ One high rate signal: N low rate signals: Frequency selective fading Frequency flat fading November 2012 | LTE Introduction | 23
  • 24. COFDM Mapper X + XDatawith OFDMFEC Σ ..... symboloverhead Mapper X + X November 2012 | LTE Introduction | 24
  • 25. OFDM signal generation 00 11 10 10 01 01 11 01 …. e.g. QPSKh*(sinjwt + cosjwt) h*(sinjwt + cosjwt) => Σ h * (sin.. + cos…) Frequency time OFDM symbol duration Δt 2012 | November LTE Introduction | 25
  • 26. 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 N 1 N 1 n n H n   hk e 2 j k n / N   hk cos(2  k )  j  hk sin(2  k ); k 0 k 0 N k 0 N N 1  2 j k n 1 hk  N H e n 0 n N ; November 2012 | LTE Introduction | 26
  • 27. OFDM Implementation with FFT(Fast Fourier Transformation)Transmitter Channel d(0) Map IDFT NFFT d(1) P/S S/Pb (k ) Map . s(n) . . d(FFT-1) Map h(n)Receiver d(0) Demap n(n) DFT NFFT d(1) P/Sˆ k S/Pb( ) Demap . r(n) . . d(FFT-1) Demap November 2012 | LTE Introduction | 27
  • 28. Inter-Carrier-Interference (ICI) 10 SMC  f  0 -10 -20  -30 xx S -40 -50 -60 -70 -1 -0.5 0 0.5 1   f-2 f-1 f0 f1 f2 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 | 28
  • 29. Rectangular Pulse A(f) Convolution sin(x)/x t f Δt Δf time frequency November 2012 | LTE Introduction | 29
  • 30. Orthogonality Orthogonality condition: Δf = 1/Δt Δf November 2012 | LTE Introduction | 30
  • 31. ISI and ICI due to channel Symbol l-1 l l+1  h  n n Receiver DFT Window Delay spread fade in (ISI) fade out (ISI) November 2012 | LTE Introduction | 31
  • 32. ISI and ICI: Guard Intervall Symbol l-1 l l+1  h  n TG  Delay Spread n Receiver DFT Window Delay spread Guard Intervall guarantees the supression of ISI! November 2012 | LTE Introduction | 32
  • 33. Guard Intervall as Cyclic Prefix Cyclic Prefix Symbol l-1 l l+1  h  n TG  Delay Spread n Receiver DFT Window Delay spread Cyclic Prefix guarantees the supression of ISI and ICI! November 2012 | LTE Introduction | 33
  • 34. Synchronisation Cyclic Prefix OFDM Symbol : l  1 l l 1 CP CP CP CP Metric - Search window ~ n November 2012 | LTE Introduction | 34
  • 35. DL CP-OFDM signal generation chain l OFDM signal generation is based on Inverse Fast Fourier Transform (IFFT) operation on transmitter side: Data QAM N Useful 1:N OFDM Cyclic prefixsource Modulator symbol IFFT N:1 OFDM symbols insertion streams symbols Frequency Domain Time Domain l On receiver side, an FFT operation will be used. November 2012 | LTE Introduction | 35
  • 36. 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 | 36
  • 37. MIMO =Multiple Input Multiple Output Antennas November 2012 | LTE Introduction | 37
  • 38. MIMO is defined by the number of Rx / Tx Antennasand not by the Mode which is supported Mode1 1 SISO Typical todays wireless Communication System Single Input Single Output Transmit Diversity1 1 MISO l Maximum Ratio Combining (MRC) l Matrix A also known as STCM Multiple Input Single Output l Space Time / Frequency Coding (STC / SFC) Receive Diversity 1 1 SIMO l Maximum Ratio Combining (MRC) Single Input Multiple Output Receive / Transmit Diversity M Spatial Multiplexing (SM) also known as: l Space Division Multiplex (SDM) l True MIMO 1 1 MIMO l Single User MIMO (SU-MIMO) Multiple Input Multiple Output l Matrix B M M Space Division Multiple Access (SDMA) also known as: l Multi User MIMO (MU MIMO) l Virtual MIMO Definition is seen from Channel l Collaborative MIMO Multiple In = Multiple Transmit Antennas Beamforming November 2012 | LTE Introduction | 38
  • 39. MIMO modes in LTE -Spatial Multiplexing-Tx diversity -Multi-User MIMO-Beamforming-Rx diversity Increased Increased Throughput per Throughput at Better S/N UE Node B November 2012 | LTE Introduction | 39
  • 40. Diversity – some thoughtsThe SISO channel: Fading on the air interface h11 transmit signal s received signal r j r  h11  s  n  h11 e s  n Amplitude phase scaling rotation The transmit signal is modified in amplitude and phase plus additional noise November 2012 | LTE Introduction | 40
  • 41. Diversity – some thoughts: matched filterThe SISO channel and matched filter (maximum ratio combining): h11 h*11 received signal r estimated signal ř transmit signal s ~  h* r  h* h s  h* n  h e  j h e j s  h* n  h 2 s  h* n r 11 11 11 11 11 11 11 11 11 Idea: matched filter multiplies received signal with conjugate of channel -> maximizes SNR Transmitted signal s is estimated as: ~ r ~ s 2 h11 November 2012 | LTE Introduction | 41
  • 42. Diversity – some thoughts: performance of SISO Euclidic distance Detector 0 threshold 1 Decay with SNR, only one channel available - > fading will deteriorate noise amplitude Bit error rate distribution Modulation Bit error Data rate = bits scheme probability per symbol BPSK 1/(4*SNR) 1 QPSK 1/(2*SNR) 2 16 QAM 5/(2*SNR) 4 November 2012 | LTE Introduction | 42
  • 43. RX DiversityMaximum Ratio Combining depends on different fading of thetwo received signals. In other words decorrelated fading channels November 2012 | LTE Introduction | 43
  • 44. Receive diversity gain – SIMO: 1*NRx Receive antenna 1 time r1=h11s+n1Transmit s NTx NRx h11antenna Receive antenna 2 h12 r2=h12s+n2 h1NRx Receive antenna NRx rnrx=h1nrxs+nnrx ~  h* s  h* s  ...  h* s r 11 1 12 2 1nRX nRX Said:   h11  h12  ...  h1nRx  s  h n  h n  ...  h 2 2 2   * * * nnRx diversity   11 1 12 2 1nRx order nRx signal after maximum ratio combining 1 Pe ~ Probability for errors SNR nRx November 2012 | LTE Introduction | 44
  • 45. TX Diversity: Space Time Coding Fading on the air interface data The same signal is transmitted at differnet antennas space Aim: increase of S/N ratio  increase of throughput  s1  s2  *S2   *  Alamouti Coding = diversity gain time approaches  s2 s1  RX diversity gain with MRRC! Alamouti Coding -> benefit for mobile communications November 2012 | LTE Introduction | 45
  • 46. Space Time Block Coding according to Alamouti (when no channel information at all available at transmitter) d e1  h1  r1  h2  r2   h1 ²  h2 ²  d1  n1 * * From slide before: d e 2  h2  r1  h1  r2   h1 ²  h2 ²  d 2  n2 * * Probability for errors (Alamouti) 1 Pe ~ SNR 2 Compare with Rx diversityAlamouti coding is full diversity gainand full rate, but it only works for 1 Pe ~2 antennas SNR nRx(due to Alamouti matrix is orthogonal) November 2012 | LTE Introduction | 46
  • 47. MIMO Spatial Multiplexing C=B*T*ld(1+S/N) SISO: Single Input Single OutputHigher capacity without additional spectrum! MIMO: S C   T  B  ld (1  ) ? min( N T , N R ) i i i 1 N Multiple Input i Multiple Output Increasing capacity per cell November 2012 | LTE Introduction | 47
  • 48. Spatial multiplexing – capacity aspects Ergodic mean capacity of a SISO channel calculated as: h11 2 C  EH {log 2 (1   h11 )} r  s  h11  n Received signal r with sent signal s, channel h11 and AWGN with σ=n P   represents the signal to noise ratio SNR 2 at the receiver branchOr simplified:  S With B = bandwidth C  B * log 2 1   and S/N = signal to  N noise ratio November 2012 | LTE Introduction | 48
  • 49. Spatial multiplexing – capacity aspects Ergodic mean capacity of a MIMO channel is even worse        H   C  EH l og 2 det  I nR  HH         nT    n1 n1 n2 n2InR is an Identity matrix with size nT x nR nT nR r  sH nHH is the Hermetian complex Received signal r with sent signal s, channel H and AWGN with σ=n November 2012 | LTE Introduction | 49
  • 50. Spatial multiplexing – capacity aspects Some theoretical ideas:       H   C  EH l og 2 det  I nR  HH    EH nR * log 2 1          nT    We increase to number of HH H lim  I nR transmit antennas to ∞, and see: nT  nTSo the result is, if the number of Tx antennas is infinity, thecapacity depends on the number of Rx antennas:After this heavy mathematics the result: If we increase thenumber of Tx and Rx antennas, we can increase the capacity! November 2012 | LTE Introduction | 50
  • 51. The MIMO promisel Channel capacity grows linearly with antennas  Max Capacity ~ min(NTX, NRX)l Assumptions  l Perfect channel knowledge l Spatially uncorrelated fadingl Reality  l Imperfect channel knowledge l Correlation ≠ 0 and rather unknown November 2012 | LTE Introduction | 51
  • 52. 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 | 52
  • 53. MIMO – capacity calculations, e.g. 2x2 MIMO n1 h11 s1 r1 h12 n2 h21 s2 r2 h22This results in the equations: Or as matrix: r1 = s1*h11 + s2*h21 + n1  r1   h11 h12   s1   n1  r2 = s2*h22 + s1*h12 + n2 r   h  *  s   n   2   21 h22   2   2  100% General written as: r = s*H +n To solve this equation, we have to know H November 2012 | LTE Introduction | 53
  • 54. Introduction – Channel Model II Correlation of propagation h11 pathes h21 s1 r1 hMR1 h12 s2 h22 r2 estimates Transmitter hMR2 Receiver h1MT h2MT NTx NRx sNTx hMRMT rNRx antennas antennas s H 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 | 54
  • 55. Spatial Multiplexing prerequisitesDecorrelation is achieved by:l Decorrelated data content on each spatial stream difficultl Large antenna spacing Channel conditionl Environment with a lot of scatters near the antenna (e.g. MS or indoor operation, but not BS) Technicall Precoding assist But, also possible that decorrelationl Cyclic Delay Diversity is not given November 2012 | LTE Introduction | 55
  • 56. MIMO: channel interference + precodingMIMO 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 | 56
  • 57. MIMO: Principle of linear equalizing R = S*H + nTransmitter will send reference signals or pilot sequenceto enable receiver to estimate H. n H-1 Rx s r ^ r Tx 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 | 57
  • 58. Linear equalization – compute power increase h11 H = h11 SISO: Equalizer has to estimate 1 channel h11 h12 h11 h12 H= h21 h22 h21 h22 2x2 MIMO: Equalizer has to estimate 4 channels November 2012 | LTE Introduction | 58
  • 59. transmission – reception model noise s + r A H R transmitter channel receiver •Modulation, •detection, •Power •estimation •„precoding“, •Eliminating channel •etc. Linear equalization impact at receiver is not •etc. very efficient, i.e. noise can not be cancelled November 2012 | LTE Introduction | 59
  • 60. MIMO – work shift to transmitter Channel ReceiverTransmitter November 2012 | LTE Introduction | 60
  • 61. MIMO Precoding in LTE (DL)Spatial multiplexing – Code book for precoding Code book for 2 Tx: Codebook Number of layers  index 1 2 Additional multiplication of the 1  1 1 0 0 0      2 0 1  layer symbols with codebook 0  1 1 1  entry 1 1      2 1 1 1 1 1 1 1  2    2 1 2  j  j 1 1 3   - 2 1 1 1  4   - 2  j 1 1 5   - 2  j  November 2012 | LTE Introduction | 61
  • 62. MIMO precoding precodingAnt1Ant2 t +  1 2 1 ∑ t + 1 precoding -1 1 ∑=0 t t November 2012 | LTE Introduction | 62
  • 63. MIMO – codebook based precodingPrecodingcodebook noise s + r A H R transmitter channel receiver Precoding Matrix Identifier, PMICodebook based precoding createssome kind of „beamforming light“ November 2012 | LTE Introduction | 63
  • 64. MIMO: avoid inter-channel interference – future outlooke.g. linear precoding: V1,k Y=H*F*S+V S Link adaptation + Transmitter H Space time F receiver xk + yk VM,k Feedback about H Idea: F adapts transmitted signal to current channel conditions November 2012 | LTE Introduction | 64
  • 65. MAS: „Dirty Paper“ Coding – future outlookl 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 „Known „Known Interference Interference Interference Interference is No is No is No is No Interference“ Interference“ Interference“ Interference“ November 2012 | LTE Introduction | 65
  • 66. 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 | 66
  • 67. Idea of Singular Value Decomposition s1 MIMO r1 know r=Hs+n s2 r2 channel H Singular Value Decomposition ~ s1 ~ r1 SISO wanted ~ ~ s2 r2 ~ ~ ~ r=Ds+n channel D November 2012 | LTE Introduction | 67
  • 68. Singular Value Decomposition (SVD) h11 h12 r= H s + n h21 h22 h11 h0 d1 12 r= U H (V*)T s + n h0 h22 21 d2 d1 0 (U*)T r= (U*)T U D (V*)T s + (U*)T n 0 d2 ~ = (U*)T U d1 0 ~ ~ (U*)T r D (V*)T s + (U*)T n 0 d2 November 2012 | LTE Introduction | 68
  • 69. 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  i eigenvalues of (H*)T H  0 0   2  0 0 3  singular values  i  i  0  0  ~ = (U*)T r r ~ ~= Σ s + n r ~ ~ s = (V*)T s ~ = (U*)T n n November 2012 | LTE Introduction | 69
  • 70. MIMO and singular value decomposition SVDReal channel n1 h11 s1 r1 h12 n2 h21 s2 r2 h22Channel model with SVD n1 s1 σ1 r1 U Σ VH n2 s2 σ2 r2 SVD transforms channel into k parallel AWGN channels November 2012 | LTE Introduction | 70
  • 71. MIMO: Signal processing considerations MIMO transmission can be expressed as r = Hs+n which is, using SVD = UΣVHs+n n1s1 σ1 r1 V U Σ VH n2 UHs2 σ2 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*UHSo 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 | 71
  • 72. MIMO: limited channel feedback Transmitter H Receiver n1 s1 σ1 r1 V U Σ VH n2 UH s2 σ2 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 | 72
  • 73. Cyclic Delay Diversity, CDD A2 A1 Amp litud D eTransmitter B Delay Spread Time Delay Multipath propagation precoding +  + precoding Time No multipath propagation Delay November 2012 | LTE Introduction | 73
  • 74. „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 Rank indicatorAdaptive Precoding matrix („Pre-equalisation“)Feedback from receiver needed (closed loop) November 2012 | LTE Introduction | 74
  • 75. MIMO transmission modes Transmission mode2 Transmission mode3 TX diversityTransmission mode1 Open-loop spatial SISO multiplexing 7 transmission Transmission mode4 Transmission mode7 Closed-loop spatial modes are SISO, port 5 multiplexing defined = beamforming in TDD Transmission mode6 Transmission mode5 Closed-loop Multi-User MIMO spatial multiplexing, using 1 layerTransmission mode is given by higher layer IE: AntennaInfo November 2012 | LTE Introduction | 75
  • 76. MIMO transmission modes the classic: 1Tx + 1RXTransmission mode1 antenna SISO PDCCH indication via DCI format 1 or 1A PDSCH transmission via single antenna port 0 No feedback regarding antenna selection or precoding needed November 2012 | LTE Introduction | 76
  • 77. MIMO transmission modesTransmission mode 2 Transmit diversity PDCCH indication via DCI format 1 or 1A Codeword is sent redundantly over several streams1 codeword PDSCH transmission via 2 Or 4 antenna ports No feedback regarding antenna selection or precoding needed November 2012 | LTE Introduction | 77
  • 78. MIMO transmission modes No feedback regarding antenna selection or Transmission mode 3 precoding needed Transmit diversity or Open loop spatial multiplexing PDCCH indication via DCI format 1A 1 codeword PDSCH transmission Via 2 or 4 antenna ports PDCCH indication via DCI format 2A 1 2codeword codewords PMI feedback PDSCH spatial multiplexing PDSCH spatial multiplexing, using CDD with 1 layer November 2012 | LTE Introduction | 78
  • 79. MIMO transmission modes Closed loop MIMO = UE feedback needed regarding Transmission mode 4 precoding and antenna Transmit diversity or Closed loop selection spatial multiplexing PDCCH indication via DCI format 1A 1 codeword PDSCH transmission Via 2 or 4 antenna ports PDCCH indication via DCI format 2 precoding precoding 1 2codeword codewords PMI feedback PMI feedback PDSCH spatial multiplexing PDSCH spatial multiplexing with 1 layer November 2012 | LTE Introduction | 79
  • 80. MIMO transmission modes Transmission mode 5 Transmit diversity or Multi User MIMO PDCCH indication via DCI format 1A 1 codeword PDSCH transmission Via 2 or 4 antenna ports PUSCH UE1Codeword PDCCH indication via DCI format 1D UE2 PDSCH multiplexing to several UEs.Codeword PUSCH multiplexing in Uplink November 2012 | LTE Introduction | 80
  • 81. MIMO transmission modes Closed loop MIMO = UE feedback needed regarding Transmission mode 6 precoding and antennaTransmit diversity or Closed loop selection spatial multiplexing with 1 layer PDCCH indication via DCI format 1A1 codeword PDSCH transmission via 2 or 4 antenna ports PDCCH indication via DCI format 1B Codeword is split into 1 streams, both streams havecodeword to be combined feedback PDSCH spatial multiplexing, only 1 codeword November 2012 | LTE Introduction | 81
  • 82. MIMO transmission modes Transmission mode 7Transmit diversity or beamforming PDCCH indication via DCI format 1A1 codeword PDSCH transmission via 1, 2 or 4 antenna ports PDCCH indication via DCI format 1 1codeword PDSCH sent over antenna port 5 = beamforming November 2012 | LTE Introduction | 82
  • 83. Beamforming Closed loop precoded Adaptive Beamforming beamforming•Classic way •Kind of MISO with channel knowledge at transmitter•Antenna weights to adjust beam •Precoding based on feedback•Directional characteristics •No specific antenna•Specific antenna array geometrie array geometrie•Dedicated pilots required •Common pilots are sufficient November 2012 | LTE Introduction | 83
  • 84. Spatial multiplexing vs beamformingSpatial multiplexing increases throughput, but looses coverage November 2012 | LTE Introduction | 84
  • 85. Spatial multiplexing vs beamforming Beamforming increases coverage November 2012 | LTE Introduction | 85
  • 86. Basic OFDM parameter LTE 1 f  15 kHz  T Fs  N FFT  f N FFT Fs   3.84Mcps 256 f NFFT  2048 Coded symbol rate= R Sub-carrier CP S/P Mapping IFFT insertion N TX Data symbols Size-NFFT November 2012 | LTE Introduction | 86
  • 87. 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 subframeWe talk about 1 slot, but the minimum resource is 1 subframe = 2 slots !!!!! Ts  1 15000  2048 Ts = 32.522 ns November 2012 | LTE Introduction | 87
  • 88. Resource block definition 1 slot = 0,5msecResource block=6 or 7 symbolsIn 12 subcarriers 12 subcarriers Resource element DL UL N symb or N symb 6 or 7, Depending on cyclic prefix November 2012 | LTE Introduction | 88
  • 89. LTE DownlinkOFDMA time-frequency multiplexing frequency QPSK, 16QAM or 64QAM modulation UE4 1 resource block = 180 kHz = 12 subcarriers UE5 UE3 UE2 UE6 Subcarrier spacing = 15 kHz time UE1 1 subframe =*TTI = transmission time interval 1 slot = 0.5 ms = 1 ms= 1 TTI*=** For normal cyclic prefix duration 7 OFDM symbols** 1 resource block pair November 2012 | LTE Introduction | 89
  • 90. 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 | 90
  • 91. LTE Downlink: FDD channel mapping example Subcarrier #0 RB November 2012 | LTE Introduction | 91
  • 92. LTE – spectrum flexibility l LTE physical layer supports any bandwidth from 1.4 MHz to 20 MHz in steps of 180 kHz (resource block) l Current LTE specification supports only a subset of 6 different system bandwidths l All UEs must support the maximum bandwidth of 20 MHz Channel Bandwidth [MHz] Channel Transmission Bandwidth Configuration [RB]bandwidth Transmission BWChannel 1.4 3 5 10 15 20 Bandwidth [RB] Channel edge Channel edge [MHz] Resource block FDD andTDD mode 6 15 25 50 75 100 number of resource blocks Active Resource Blocks DC carrier (downlink only) November 2012 | LTE Introduction | 92
  • 93. LTE Downlink: baseband signal generationcode words layers antenna ports Modulation OFDM OFDM signal Scrambling Mapper Mapper generation Layer Precoding Mapper Modulation OFDM OFDM signal Scrambling Mapper Mapper generation 1 stream = several Avoid QPSK For MIMO Weighting 1 OFDM subcarriers, constant 16 QAM Split into data symbol per based onsequences 64 QAM Several streams for stream Physical streams if MIMO ressource needed blocks November 2012 | LTE Introduction | 93
  • 94. Adaptive modulation and coding Transportation block size User data FECFlexible ratio between data and FEC = adaptive coding November 2012 | LTE Introduction | 94
  • 95. Channel Coding Performance November 2012 | LTE Introduction | 95
  • 96. 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 | 96
  • 97. HARQ principle: Stop and Wait Δt = Round trip timeTx Data Data Data Data Data Data Data Data Data Data ACK/NACK Demodulate, decode, descramble, Rx FFT operation, check CRC, etc. process Processing time for receiver Described as 1 HARQ process November 2012 | LTE Introduction | 97
  • 98. HARQ principle: Multitasking Δt = Round trip timeTx Data Data Data Data Data Data Data Data Data Data ACK/NACK Demodulate, decode, descramble, Rx FFT operation, check CRC, etc. process ACK/NACK Processing time for receiver Rx Demodulate, decode, descramble, process FFT operation, check CRC, etc. t Described as 1 HARQ process November 2012 | LTE Introduction | 98
  • 99. LTE Round Trip Time RTT n+4 n+4 n+4 ACK/NACK PDCCH PHICH Downlink HARQ Data Data UL Uplinkt=0 t=1 t=2 t=3 t=4 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 | 99
  • 100. HARQ principle: Soft combininglT i is a e am l o h n e co i g Reception of first transportation block. Unfortunately containing transmission errors November 2012 | LTE Introduction | 100
  • 101. HARQ principle: Soft combining l hi i n x m le f cha n l c ing Reception of retransmitted transportation block. Still containing transmission errors November 2012 | LTE Introduction | 101
  • 102. 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 | 102
  • 103. Hybrid ARQChase 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 | 103
  • 104. Hybrid ARQIncremental 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 | 104
  • 105. LTE Physical Layer: SC-FDMA in uplinkSingle Carrier Frequency Division Multiple Access November 2012 | LTE Introduction | 105
  • 106. LTE Uplink:How to generate an SC-FDMA signal in theory? Coded symbol rate= R Sub-carrier CP DFT Mapping IFFT 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 | 106
  • 107. 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 | 107
  • 108. 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 QPSK, 16QAM or 64QAM modulation November 2012 | LTE Introduction | 108
  • 109. LTE Uplink: baseband signal generation UE specificScrambling code Modulation Transform Resource SC-FDMA Scrambling element mapper mapper precoder signal gen. Mapping on physical 1 stream = Discrete Ressource, several Avoid QPSK Fourier i.e. subcarriers, constant 16 QAM Transform subcarriers based onsequences 64 QAM not used for Physical (optional) reference ressource signals blocks November 2012 | LTE Introduction | 109
  • 110. LTE Protocol Architecture November 2012 | LTE Introduction | 110
  • 111. LTE Protocol ArchitectureReduced complexity l Reduced number of transport channels l Shared channels instead of dedicated channels l Reduction of Medium Access Control (MAC) entities l Streamlined concepts for broadcast / multicast (MBMS) l No inter eNodeB soft handover in downlink/uplink l No compressed mode l Reduction of RRC states November 2012 | LTE Introduction | 111
  • 112. EUTRAN stack: protocol layers overview EMM ESM User plane Radio Resource Control RRC Packet Data Convergence PDCP Control & Measurements Radio Bearer Radio Link Control RLC Logical channels Medium Access Control MAC Transport channels PHYSICAL LAYER November 2012 | LTE Introduction | 112
  • 113. User plane Header compression (ROHC) In-sequence delivery at handover Duplicate detection Ciphering for user/control plane Integrity protection for control plane Timer based SDU discard in Uplink… UE eNB AM, UM, TM ARQ PDCP PDCP (Re-)segmentation Concatenation RLC RLC In-sequence delivery Duplicate detection MAC MAC SDU discard Reset… PHY PHY Mapping between logical and PDCP = Packet Data Convergence Protocol transport channels RLC = Radio Link Control (De)-Multiplexing MAC = Medium Access Control Traffic volume measurements PHY = Physical Layer HARQ SDU = Service Data Unit Priority handling (H)ARQ = (Hybrid) Automatic Repeat Request Transport format selection… November 2012 | LTE Introduction | 113
  • 114. Control plane Broadcast Paging RRC connection setup Radio Bearer Control Mobility functions UE measurement control… UE eNB MME NAS NAS RRC RRC PDCP PDCP RLC RLC EPS bearer management Authentication MAC MAC ECM_IDLE mobility handling Paging origination in ECM_IDLE Security control… PHY PHY EPS = Evolved packet system RRC = Radio Resource Control NAS = Non Access Stratum ECM = EPS Connection Management November 2012 | LTE Introduction | 114
  • 115. EPS Bearer Service Architecture E-UTRAN EPC Internet UE eNB S-GW P-GW Peer Entity End-to-end Service EPS Bearer External Bearer Radio Bearer S1 Bearer S5/S8 Bearer Radio S1 S5/S8 Gi November 2012 | LTE Introduction | 115
  • 116. Channel structure: User + Control plane Protocol structure November 2012 | LTE Introduction | 116
  • 117. LTE channel mappingNovember 2012 | LTE Introduction | 117
  • 118. LTE – channels MTCH MCCH CCCH DCCH DTCH PCCH BCCH DL logical channels MCH DL-SCH PCH BCH DL transport channels DL physical channelsPMCH PCFICH PDCCH PDSCH PHICH PBCH CCCH DCCH DTCH UL logical channels RACH UL-SCH UL transport channels UL physical channels PRACH PUCCH PUSCH November 2012 | LTE Introduction | 118
  • 119. LTE – uplink channelsMapping between logical and transport channels CCCH DCCH DTCH Uplink Logical channels Uplink Transport channels RACH UL-SCH November 2012 | LTE Introduction | 119
  • 120. LTE resource allocation principles November 2012 | LTE Introduction | 120
  • 121. LTE resource allocation Scheduling of downlink and uplink data Check PDCCH for your UE ID. You may find here Uplink and/or Downlink Physical Uplink Shared Channel resource allocation information (PUSCH) Physical Downlink Control Physical Downlink Shared Channel (PDCCH) Channel (PDSCH) Physical Control Format I would like to receive data on PDSCHIndicator Channel (PCFICH), and / or send data on PUSCH Info about PDCCH format ? November 2012 | LTE Introduction | 121
  • 122. Resource allocation types in LTEAllocation type DCI Format Scheduling Antenna Type configurationType 0 / 1 DCI 1 PDSCH, one SISO, codeword TxDiversity DCI 2A PDSCH, two MIMO, open codewords loop DCI 2 PDSCH, two MIMO, closed codewords loopType 2 DCI 0 PUSCH SISO DCI 1A PDSCH, one SISO, codeword TxDiversity DCI 1C PDSCH, very SISO compact codeword November 2012 | LTE Introduction | 122
  • 123. Resource allocation types in LTEType 0 and 1 for distributed allocation in frequency domain Channel bandwidth f Type 2 for contiguous allocation in frequency domain Channel bandwidth Transmission bandwidth f November 2012 | LTE Introduction | 123
  • 124. Resource Block Group Reminder: 1 resource block = 12 subcarriers in frequency domain f Resource allocation is performed based on resource block groups. 1 resource block group may consist of 1, 2, 3 or 4 resource blocks Resource block groups, RBG sizes November 2012 | LTE Introduction | 124
  • 125. Resource allocation type 0Type 0 (for distributed frequency allocation of Downlink resource,SISO and MIMO possible)l Bitmap to indicate which resource block groups, RBG are allocatedl One RBG consists of 1-4 resource blocks: Channel RBG size P bandwidth ≤10 1l Granularity is RBG size 11-26 2 27-63 3l Number of resource block groups NRBG 64-110 4is given as:  N RBG  N RB / P DL l Allocation bitmap has same length than NRBG November 2012 | LTE Introduction | 125
  • 126. Resource allocation type 0 example Calculation example for type 0:l Channel bandwidth = 10MHzl -> 50 resource blocksl -> Resource block group RBG size = 3l -> bitmap size = 17 if N RB mod P  0 DL then one of the RBGs is of size DL  N RB  P  N RB / P DL  i.e. here 50 mod 3 = 16, so the last resource block group has the size 2.-> some allocations are not possible, e.g. here you can allocate48 or 50 resource blocks, but not 49!  N RBG  N RB / P DL  = round up, i.e.3.5 = 4 reminder  DL N RB / P  = round down, i.e. 3.49 = 3 November 2012 | LTE Introduction | 126
  • 127. Resource allocation type 0: exampleChannel bandwidth = 10MHz -> 50 RBs -> RBG size = 3 -> number of RBGs = 17RBG#0 RBG#1 RBG#6 RBG#NRBG-10 1 2 3 16 17 18 19 20 21 22 23 N RB  3 N RB  2 N RB  1 DL DL DLAllocation bitmap (17bit): 10000011000000001 Granularity: 1 bit allocates 1 ressource block group ´f November 2012 | LTE Introduction | 127
  • 128. Resource allocation type 1Type 1 (for distributed frequency allocation of Downlink resource,SISO and MIMO possible)One Resource Block Groupconsists of 1-4 resource blocks: Channel RBG size P bandwidthl RBs are divided into log 2 ( P)  ≤10 1RBG subsets 11-26 2l Granularity is resource block 27-63 3 64-110 4l Bitmap indicates RBs inside a RBG subset allocated to the UEl Resource block assignment consists of 3 fields: l Field to indicate the selected RBG l Field to indicate a shift of the resource allocation l Field to indicate the specific RB within a RBG subset November 2012 | LTE Introduction | 128
  • 129. Resource allocation type 1 Channel bandwidth = 10MHz -> 50 RBs -> RBG size = 3 -> number of RBGs = 17RBG#0 RBG#1 RBG#NRBG-10 1 2 3 16 17 18 19 20 21 22 23 N RB  3 N RB  2 N RB  1 DL DL DL Size 18 resource blocks RBG subset #0 RBG#0 RBG#3 RBG#6 RBG#9 RBG#12 RBG#15 Size 17 resource blocks RBG#1 RBG#4 RBG#7 RBG#10 RBG#13 RBG#16 RBG subset #1 Size 15 resource blocks RBG#2 RBG#5 RBG#8 RBG#11 RBG#14 RBG subset #2P= Number of RBG subsets with length:  N RB  1 DL  N DL  1  2 P P , p   RB  mod P  P   P  log 2 ( P)  DL  N  1  N RB  1 DL N RB subset ( p)   RB 2   P  ( N RB  1) mod P  1 RBG DL ,p  mod P  P   P   DL  N RB  1  P   N DL  1 , p   RB  mod P indicate subset  P  2 Number of bits to   P  November 2012 | LTE Introduction | 129
  • 130. Resource allocation type 1Channel bandwidth = 10MHz -> 50 RBs -> RBG size = 3 -> number of RBGs = 17RBG#0 RBG#1 RBG#NRBG-10 1 2 3 16 17 18 19 20 21 22 23 N RB  2 N RB  1 DL DLRBG#0 RBG#3 RBG#6 RBG#9 RBG#12 RBG#15 RBG#2 RBG#5 RBG#8 RBG#11 RBG#14 RBG subset #0 RBG subset #2Size 17 resource blocks RBG#1 RBG#4 RBG#7 RBG#10 RBG#13 RBG#16 RBG subset #13 4 5 12 13 14 21 22 23 30 31 32 39 40 41 48 49 Resource blocks assignment Field 1: RBG subset selection Field 2: offset shift indication Field 3: resource block allocationAllocation bitmap (17bit): 01 0 00011000000001 Size 14 bits RBG subset#1 is selected Bit = 0, no shift November 2012 | LTE Introduction | 130
  • 131. Resource allocation type 1Channel bandwidth = 10MHz -> 50 RBs -> RBG size = 3 -> number of RBGs = 17The meaning of the shift offset bit:Number of resource blocks in one RBG subset is bigger than the allocation bitmap -> you can not allocate all the available resource blocks-> offset shift to indicate which RBs are assigned 17 resource blocks belonging to the RBG subset#1 RBG#1 RBG#4 RBG#7 RBG#10 RBG#13 RBG#16 RBG subset #1 4 5 12 13 14 21 22 23 30 31 32 39 40 41 48 49 Resource blocks3 assignmentAllocation bitmap (17bit): 01 0 10000000000001 RBG subset#1 is selected 14 bits in allocation bitmap Bit = 0, no shift November 2012 | LTE Introduction | 131
  • 132. Resource allocation type 1Channel bandwidth = 10MHz -> 50 RBs -> RBG size = 3 -> number of RBGs = 17The meaning of the shift offset bit:Number of resource blocks in one RBG subset is bigger than the allocation bitmap -> you can not allocate all the available resource blocks-> offset shift to indicate which RBs are assigned 17 resource blocks belonging to the RBG subset #1 RBG#1 RBG#4 RBG#7 RBG#10 RBG#13 RBG#16 RBG subset #13 4 5 1 14 21 22 23 30 31 32 39 40 41 48 49 Resource blocks 12 3 assignmentAllocation bitmap (17bit): 01 1 10000000000001 RBG subset#1 is selected 14 bits in allocation bitmap Bit = 1, offset shift November 2012 | LTE Introduction | 132
  • 133. Resource allocation types in LTEType 0 allows the allocation based on resource block groups granularity Channel bandwidth Example: RBG size = 3 RBs fType 1 allows the allocation based on resource block granularity Channel bandwidth 1 resource block, RB f November 2012 | LTE Introduction | 133
  • 134. Resource allocation type 2Localized mode Starting resource block: RBStart LCRB, length of contiguously allocated RBs Number of allocated Resource blocks NRB Channel bandwidth Transmission bandwidthRB#0 fResource block offset November 2012 | LTE Introduction | 134
  • 135. Resource indication value, RIVType 0: bitmap used to indicate the resource allocation: N RB / P = Length of allocation bitmap (17bit): 10000011000000001 DL RIV = bin toType 1: bitmap used to indicate the resource allocation, with 3 fields: dec conversionResource block group subset, shift indictor + resource allocation Allocation bitmap (17bit): 01 1 10000000000000Type 2: TS 36.213 section 7.1.6.3. gives formula to calculate RIV: if ( LCRBs  1)  N RB / 2 DL then RIV  N RB ( LCRBs  1)  RBstart DL else RIV  N RB ( N RB  LCRBs  1)  ( N RB  1  RBstart ) DL DL DL November 2012 | LTE Introduction | 135
  • 136. Resource indication value, RIV in type 2 allocationHow to calculate the RIV value in allocation type 2, according to TS 36.213 Assumptions and given: Starting resource block: RBStart=5 Localized mode, RBStart = 5, LCRB = 20 NDLRB = 50 LCRB, length of contiguously allocated RBs=20 f RIV  N DL RB ( LCRBs  1)  RBstart Formula from TS 36.213 Here: RIV = 50 * (20-1) + 5 RIV = 955 November 2012 | LTE Introduction | 136
  • 137. 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 | 137
  • 138. Resource allocation Uplink Allocation type DCI Format Scheduling Antenna Type configuration Type 0 / 1 DCI 1 PDSCH, one codeword SISO, TxDiversity DCI 2A PDSCH, two MIMO, open loopLTE Uplink uses codewordsType 2 allocation DCI 2 PDSCH, two MIMO, closed loop codewords Type 2 DCI 0 PUSCH SISO DCI 1A PDSCH, one codeword SISO, TxDiversity DCI 1C PDSCH, very compact SISO codewordStarting resource block: RBStart LCRB, length of contiguously allocated RBsRB#0 Channel bandwidth November 2012 | LTE Introduction | 138
  • 139. LTE Uplink: allocation of UL ressource Scheduled UL UL bandwidth bandwidth configuration 2 3 5 PUSCH M RB 2 3 5  UL N RB Scheduled number of ressource blocks in UL must fullfill formula above(αx are integer). Possible values are: 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 27 30 32 36 40 45 48 50 54 60 64 72 75 80 81 90 96 100 November 2012 | LTE Introduction | 139
  • 140. The LTE evolution Rel-9 eICIC enhancements Relaying In-device Rel-10 Diverse Data co-existence Application CoMP Rel-11 Relaying eICIC eMBMS enhancements SON enhancements MIMO 8x8 MIMO 4x4 Carrier Enhanced Aggregation SC-FDMA Public Warning Positioning System Home eNodeB Self Organizing eMBMS Networks DL UL Multi carrier / Dual Layer DL UL Multi-RAT Beamforming Base Stations LTE Release 8 FDD / TDD November 2012 | LTE Introduction | 140
  • 141. 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 | 141
  • 142. 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 Port 0-3: Cell-specific Reference Signals (CS-RS) l Port 4: MBSFN-RS l Port 5: UE-specific Reference Signals (DM-RS): single layer (TX mode 7) l Port 6: Positioning Reference Signals (PRS) l Port 7-8: UE-specific Reference Signals (DM-RS): dual layer (TX mode 8) l Port 7-14: UE specific Referene Signals for Rel. 10 l Port 15 – 22: CSI specific reference signals, channel status info in Rel. 10 November 2012 | LTE Introduction | 142
  • 143. What are antenna ports?l Mapping „Antenna Port“ to „Physical Antennas“ Antenna Port Physical Antennas 1 AP0 PA0 AP1 1 W5,0 AP2 1 PA1 W5,1 AP3 1 PA2 AP4 … W5,2 W5,3 AP5 PA3 … AP6 AP7 … AP8 …The way the "logical" antenna ports are mapped to the "physical" TX antennas liescompletely in the responsibility of the base station. Theres no need for the base stationto tell the UE. November 2012 | LTE Introduction | 143
  • 144. 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 connected mode, scansUE in idle mode, scans for Positioning RS on antenna port 6Antenna port 0, cell specific RS to locate its position November 2012 | LTE Introduction | 144
  • 145. eMBMSPhysical Layer Scenariosl Dedicated and mixed mode. l Dedicated: carrier is only for MBMS = Single-cell MBMS. l MBMS/Unicast mixed mode: MBMS and user data are transmitted using time division duplex. Certain subframes carry MBMS data.l Dedicated mode (single-cell scenario) offers use of new subscarrier spacing, longer cyclic prefix (CP), 3 OFDM symbols. OFDM Sub- Cyclic Prefix Length Cyclic Prefix Configuration Symbols carrier in Samples Length in µs Normal CP 160 for 1st symbol 5.2 for 1st symbol 7 ∆f = 15 kHz 144 for other symbols 4.7 for other symbols 12 Extended CP 6 512 16.7 ∆f = 15 kHz Extended CP eMBMS 3 24 1024 33.3 ∆f = 7.5 kHz (Single cell scenario) November 2012 | LTE Introduction | 145
  • 146. Resource block definition for MBMS Δf=1/TSYMBOL=15kHz 1 Resource Block =12 subcarriers f f0 f1 f2 1 2 3 4 5 6 7 7 OFDM symbols OFDM OFDM OFDM OFDM OFDM OFDM 6 OFDM symbolsCP Symbol CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol 1 Resource Δf= Block = 7.5kHz24 subcarriers For f MBMS OFDM OFDM OFDMCP Symbol CP Symbol CP Symbol only! November 2012 | LTE Introduction | 146
  • 147. Multimedia Broadcast Messaging Services, MBMS Broadcast: Unicast: Public info for Private info for dedicated user everybody Multicast: Common info for User after authentication November 2012 | LTE Introduction | 147
  • 148. LTE MBMS architecture November 2012 | LTE Introduction | 148
  • 149. MBMS in LTE MBMS MME GW | M3 MBMS GW: MBMS Gateway MCE: Multi-Cell/Multicast Coordination Entity M1 | MCE M1: user plane interface M2: E-UTRAN internal control plane interface M2 M3: control plane interface between E-UTRAN and EPC | eNB Logical architecture for MBMS November 2012 | LTE Introduction | 149
  • 150. MBMS broadcast service provision Service announcement Session Start MBMS notification Data transfer Session StopSee 3GPP TS23.246, Section 4.4.3 November 2012 | LTE Introduction | 150
  • 151. MBMS broadcast service provision time UE1 Local service de - UE local service activation How is the activation UE2 UE informed about all Idle period Data Data this in detail? Data of seconds transfer transfer transfer Broadcast session start Session stop Start Broadcast Stop Service announcment announcement t Service 1 session1 Service 1 Session 2 Broadcast service Announcement November 2012 | LTE Introduction | 151
  • 152. MBMS Signalingl New logical Channels: POC VoIP FTP WAP HTTP MMS SIP l MBMS point-to-multipoint Control TCP / UDP IP Channel (MCCH) l MBMS point-to-multipoint Traffic SNSM Channel (MTCH) SM SMREG TC CTC l MBMS point-to-multipoint Scheduling GMMSM MMTC GMM MM Channel (MSCH) GMMREG GMMMM GC NT DC l Reception of MSCH is optional RRC PDCP PDCP l MxCH channels are mapped on Multicast Channel MCH UM RLC PUM DCCH / MCCH MTCH MSCH DTCH MAC New SIB 13 informs MCH about MBMS configuration PHY November 2012 | LTE Introduction | 152
  • 153. MBSFNMBSFN, Multicast/Broadcast Single Frequency NetworkCells belonging to MBSFN area are co-ordinatedand transmit a time-synchronized common waveformeNodeBs within an MBSFN area are synchronized.From point of view of the terminal, this appears to be a singletransmission as if originating from one large cell(with correspondingly large delay spread).Cyclic prefix is utilized to cover the difference in the propagation delays from the multiple cells. MBMS therefore uses an extended cyclic prefix November 2012 | LTE Introduction | 153
  • 154. MBSFN – MBMS Single Frequency NetworkMobile communication network Single Frequency Networkeach eNode B sends individual each eNode B sends identicalsignals signals November 2012 | LTE Introduction | 154
  • 155. MBSFN If network is synchronised, Signals in downlink can be combined November 2012 | LTE Introduction | 155
  • 156. evolved Multimedia Broadcast Multicast Services Multimedia Broadcast Single Frequency Network (MBSFN) area l Useful if a significant number of users want to consume the same data content at the same time in the same area! l Same content is transmitted in a specific area is known as MBSFN area. 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. l MBSFN areas do not change dynamically over time. MBSFN area 0 MBSFN area 255 11 3 8 13 MBSFN reserved cell. 1 6 12 15 A cell within the MBSFNarea, that does not support 4 9 14 MBMS transmission. 2 7 13 5 10 A cell can belong to MBSFN area 1 more than one MBSFN area; in total up to 8. November 2012 | LTE Introduction | 156
  • 157. eMBMSDownlink Channelsl Downlink channels related to MBMS l MCCH Multicast Control Channel l MTCH Multicast Traffic Channel l MCH Multicast Channel l PMCH Physical Multicast Channell MCH is transmitted over MBSFN in specific subrames on physical layerl MCH is a downlink only channel (no HARQ, no RLC repetitions) l Higher Layer Forward Error Correction (see TS26.346)l Different services (MTCHs and MCCH) can be multiplexed November 2012 | LTE Introduction | 157
  • 158. 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 | 159
  • 159. eMBMS allocation based on SIB2 information 011010 Reminder: Subframes 0,4,5, and 9 Are non-MBMS November 2012 | LTE Introduction | 160
  • 160. eMBMS: MCCH position according to SIB13 November 2012 | LTE Introduction | 161
  • 161. LTE Release 9Dual-layer beamformingl 3GPP Rel-8 – Transmission Mode 7 = beamforming without UE feedback, using UE-specific reference signal pattern, l Estimate the position of the UE (Direction of Arrival, DoA), l Pre-code digital baseband to direct beam at direction of arrival, l BUT single-layer beamforming, only one codeword (TB),l 3GPP Rel-9 – Transmission Mode 8 = beamforming with or without UE feedback (PMI/RI) using UE-specific reference signal pattern, but dual-layer, l Mandatory for TDD, optional for FDD, l 2 (new) reference signal pattern for two new antenna ports 7 and 8, l New DCI format 2B to schedule transmission mode 8, l Performance test in 3GPP TS 36.521 Part 1 (Rel-9) are adopted to support testing of transmission mode 8. November 2012 | LTE Introduction | 162
  • 162. LTE Release 9Dual-layer beamforming – Reference Symbol Detailsl Cell specific antenna port 0 and antenna port 1 reference symbols Antenna Port 0 Antenna Port 1l UE specific antenna port 7 and antenna port 8 reference symbols Antenna Port 7 Antenna Port 8 November 2012 | LTE Introduction | 163
  • 163. 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 coverageSpatial multiplexing increases throughput, but looses coverage November 2012 | LTE Introduction | 164
  • 164. Location based servicesl Location Based Services“l Products and services which need location informationl Future Trend: Augmented Reality November 2012 | LTE Introduction | 165
  • 165. Where is Waldo?November 2012 | LTE Introduction | 166
  • 166. Location based servicesThe 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 | 167
  • 167. E-UTRA supported positioning methods November 2012 | LTE Introduction | 168
  • 168. LTE Release 9LTE positioningl The standard positioning methods supported for E-UTRAN access are: l network-assisted GNSS (Global Navigation Satellite System) methods – These methods make use of UEs that are equipped with radio receivers capable of receiving GNSS signals, e.g. GPS. l downlink positioning – The downlink (OTDOA – Observed Time Difference Of Arrival) positioning method makes use of the measured timing of downlink signals received from multiple eNode Bs at the UE. The UE measures the timing of the received signals using assistance data received from the positioning server, and the resulting measurements are used to locate the UE in relation to the neighbouring eNode Bs. l enhanced cell ID method – In the Cell ID (CID) positioning method, the position of an UE is estimated with the knowledge of its serving eNode B and cell. The information about the serving eNode B and cell may be obtained by paging, tracking area update, or other methods. November 2012 | LTE Introduction | 169
  • 169. E-UTRA supported positioning network architecture Control plane and user plane signaling LCS4) Client S1-U Serving S5 Packet Lup SUPL / LPP Gateway Gateway SLP1) (S-GW) (P-GW) LCS Server (LS) SLs LPPa LPP Mobile Management E-SMLC2) GMLC3) S1-MME SLs Entity (MME)LTE-capable device LTE base stationUser Equipment, UE eNodeB (eNB) (LCS Target) Secure User Plane Location positioning SUPL= user plane protocol LPP = signaling control plane 1) SLP – SUPL Location Platform, SUPL – Secure User Plane Location 2) E-SMLC – Evolved Serving Mobile Location Center signaling 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) November 2012 | LTE Introduction | 170
  • 170. E-UTRAN UE Positioning Architecturel 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).l 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 | 171 Source: 3GPP TS 36.305
  • 171. Global Navigation Satellite Systemsl 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?. l Challenging environments: l Compass (Beidou) – China, under urban, indoors, changing development, target 2015. locations. l IRNSS – India, planning process. E5a E1 L5 L5b L2 G2 E6 L1 G1 1164 1215 1237 1260 1300 1559 1591 f [MHz] 1563 1587 1610 GALLILEO GPS GLONASS Signal fCarrier [MHz] Signal fCarrier [MHz] Signal fCarrier [MHz] 1602±k*0,562 E1 1575,420 L1C/A 1575,420 G1 5 1246±k*0,562 E6 1278,750 L1C 1575,420 G2 5 E5 1191,795 L2C 1227,600 k = -7 … 13 E5a 1176,450 L5 1176,450 http://www.hindawi.com/journals/ijno/2010/812945/ E5b 1207,140 November 2012 | LTE Introduction | 172
  • 172. Assisted GNSS (A-GNSS)l The network assists the device GNSS receiver to improve the performance in several aspects: l Reduce GNSS start-up and acquisition times. l Increase GNSS sensitivity, reduce power consumption.l UE-assisted. l Device (= User Equipment, UE) Source: TS 36.355 transmits GNSS measurement LTE Positioning Protocol (LPP) results to network server, where position calculation takes place.l UE-based. l UE performs GNSS measurements and position calculation, supported by: – Data to assist these measurements, e.g. reference time, visible satellite list etc. – Data providing for position calculation, e.g. reference position, satellite ephemeris, etc. November 2012 | LTE Introduction | 173
  • 173. LTE Positioning Protocol (LPP) 3GPP TS 36.355 LPP position methods - A-GNSS Assisted Global Navigation Satellite System - E-CID Enhanced Cell ID LTE radio - OTDOA Observed time differerence of arrival signal *GNSS and LTE radio signalseNB Measurements based on reference sources* Target LPP Location Device Server Assistance data LPP over RRC UE Control plane solution E-SMLC Enhanced Serving Mobile Location Center LPP over SUPLSUPL enabled Terminal SET User plane solution SLP SUPL location platform November 2012 | LTE Introduction | 174
  • 174. LPP and lower layers LPP PDU Transfer eNB November 2012 | LTE Introduction | 175 Source: 3GPP TS 36.305
  • 175. User plane stack SUPL occupies the application layer in the LTE user plane stack, with LPP (or another positioning protocol !) transported as another layer above SUPL. November 2012 | LTE Introduction | 176 Source: 3GPP TS 36.305
  • 176. GNSS positioning methods supportedl Autonomeous GNSSl 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 | 177 Source: 3GPP TS 36.305
  • 177. GNSS candidates and augmentation systemsl GPS/Modernized GPS – Global Positioning System (USA, since 1995)l Galileo (Europe, under development, target 2013)l GLONASS (Russia)l Compass, Beidou-2 (China, under development, target 2015)l IRNSS (India, in process of planning) l SBAS – Satellite based augmentation systems – Geostationary satellites supporting error corrections by overlay signals – WAAS – Wide Area Augmentation System (USA) – EGNOS – European Geostationary Navigation Overlay Service (Europa) – MSAS – Mulit-Functional Satellite Augmentation System (Japan) – QZSS – Quasi-Zenith Satellite System (Japan, supports GPS, expected 2013) – GAGAN – GPS Aided Geo Augmented Navigation (India) November 2012 | LTE Introduction | 178
  • 178. GNSS band allocations E5a E1 L5 E5b L2 G2 E6 L1 G1 f/MHz1164 1215 1237 1260 1300 1559 1563 1587 1591 1610 November 2012 | LTE Introduction | 179
  • 179. GPS and GLONASS satellite orbits GPS: 26 Satellites Orbital radius 26560 km GLONASS: 26 Satellites Orbital radius 25510 km November 2012 | LTE Introduction | 180
  • 180. Position Determination tsj trj Rj = c·Δtj l „Pseudo distance“ Satellite – Receiver l Rj = c ·Δtj=c· (trj-tsj) = ρj + c·Δclock + ΔIono + ΔTropo + ΔMpath + ΔInt + ΔNoise – ρj = real distance („error-free“) – c·Δclock = Clock error (4th unknown variable → 4th satellite required) – ΔIono , ΔTropo = „speed of light“ error due to ionosphere and troposhere – ΔMpath , ΔInt , ΔNoise = trj uncertainty due to multipath propagation, interference, noise l Each satellite j broadcasts its current position ρSAT,j and local time tsj. l With ρSAT,j and ρj the receiver position can be evalutated l Additional signal phase measurements to increase accuracy November 2012 | LTE Introduction | 181
  • 181. Backup basic termsl Ephemeris l Table of values that gives the positions of objects in the sky at a given timel Almanach l Set of data that every satellite transmits. It includes information about the state (health) of the entire satellite constellation and coarse data on every satellite‘s orbit.l Cold start l No ephemeris, almanac or location data available (reset state)l Hot start l Location data available November 2012 | LTE Introduction | 182
  • 182. 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 | 183
  • 183. (A-)GNSS vs. mobile radio positioningmethods (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 One strong signal from the serving BS, Similar received power levels from all satellites strong interference situation Long synchronization sequences Short synchronization sequences Complete signal not a-priori known to Signal a-priori known due to low data rates support high data rates, only certain pilots Very accurate synchronization of the satellites Synchronization of the BSs not a-priori guaranteed by atomic clocks Line of sight (LOS) access as normal case Non line of sight (NLOS) access as normal case  not suitable for urban / indoor areas  suitable for urban / indoor areas 3-dimensional positioning 2-dimensional positioning November 2012 | LTE Introduction | 184
  • 184. Measurements for positioningl UE-assisted measurements. l eNB-assisted measurements. l Reference Signal Received l eNB Rx – Tx time difference. Power l TADV – Timing Advance. (RSRP) and Reference Signal – For positioning Type 1 is of Received Quality (RSRQ). relevance. l RSTD – Reference Signal Time l AoA – Angle of Arrival. Difference. l UTDOA – Uplink Time Difference l UE Rx–Tx time difference. of Arrival. TADV (Timing Advance) = eNB Rx-Tx time difference + UE Rx-Tx time difference Neighbor cell j = (TeNB-RX – TeNB-TX) + (TUE-RX – TUE-TX) UL radio frame #i RSTD – Relative time difference between a subframe received from neighbor cell j and corresponding subframe from serving cell i: TSubframeRxj - TSubframeRxi DL radio frame #i UL radio frame #i DL radio frame #i Serving cell i eNB Rx-Tx time difference is defined UE Rx-Tx time difference is defined RSRP, RSRQ are as TeNB-RX – TeNB-TX, where TeNB-RX is the as TUE-RX – TUE-TX, where TUE-RX is the measured on reference received timing of uplink radio frame #ireceived timing of downlink radio frame signals of serving cell i and TeNB-TX the transmit timing of #i from the serving cell i and TUE-TX the downlink radio frame #i. transmit timing of uplink radio frame #i. Source: see TS 36.214 Physical Layer measurements for detailed definitions November 2012 | LTE Introduction | 185
  • 185. Observed Time difference Observed Time Difference of Arrival OTDOA If network is synchronised, UE can measure time difference November 2012 | LTE Introduction | 186
  • 186. Methods‘ overview CID E-CID (RSRP/TOA/TADV) E-CID (RSRP/TOA/TADV) [Trilateration] E-CID (AOA) [Triangulation] Downlink / Uplink (O/U-TDOA) [Multilateration] RF Pattern matching To be updated!! November 2012 | LTE Introduction | 187
  • 187. Cell IDl Not new, other definition: Cell of Origin (COO). l UE position is estimated with the knowledge of the geographical coordinates of its serving eNB. l Position accuracy = One whole cell . November 2012 | LTE Introduction | 188
  • 188. 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. RSRP – Reference Signal Received Power TOA – Time of Arrival November 2012 | LTE Introduction | 189 TADV – Timing Advance RTT – Round Trip Time
  • 189. TADV – Timing Advance (Round Trip Time, RTT)l Base station measures: eNB Rx-Tx = TeNB-Rx – TeNB-Tx eNB Rx Timing of subframe nl eNB orders the device to correct its uplink timing: TA = eNB Rx-Tx eNB Tx Timing of subframe n eNB Rx-Tx. UE Rx-Tx l Timing Advance command UE Rx Timing of subframe n (MAC). UE Tx Timing of subframe nl UE measures and reports: UE Rx-Tx = TUE-Rx – TUE-Tx l LPP_IE: ue-RxTxTimeDiff. l Distance of UE to eNB is estimated as d=c*RTT/2. l c = speed of light.l eNB calculates and reports to LS: TADV = eNB Rx-Tx + UE Rx-Tx l Advantage: No l LPPa_IE: timingAdvanceType1/2 synchronization l TADV = Round Trip Time (RTT). between eNB‘s. November 2012 | LTE Introduction | 190
  • 190. Angle of Arrival (AOA)l AoA = Estimated angle of a UE with respect to a reference direction (= geographical North), positive in a counter- clockwise direction, as seen from an eNB. l Determined at eNB antenna based on a received UL signal (SRS).l Measurement at eNB: l eNB uses antenna array to estimate direction i.e. Angle of Arrival (AOA). l The larger the array, the more accurate is the estimated AOA. l eNB reports AOA to LS. l Advantage: No synchronization between eNB‘s. l Drawback: costly antenna arrays. November 2012 | LTE Introduction | 191
  • 191. OTDOA – Observed Time Difference ofArrivall UE position is estimated based on measuring TDOA of Positioning Reference Signals (PRS) embedded into overall DL signal received from different eNB’s. 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. l UE’s position = intersection of hyperbolas for at least 3 pairs of eNB’s. November 2012 | LTE Introduction | 192
  • 192. LTE Release 9UE positioning – Reference Symbol Detailsl PRS is a pseudo-random QPSK sequence similar to CRSl PRS pattern (baseline for further discussion and CR drafting): l Diagonal pattern with time varying frequency shift, l PRS mapped around CRS (to avoid collisions) Antenna Port 0 November 2012 | LTE Introduction | 193
  • 193. Positioning Reference Signals (PRS) for OTDOADefinitionl Cell-specific reference signals (CRS) are not sufficient for positioning, introduction of positioning reference signals (PRS) for antenna port 6. l SINR for synchronization and reference signals of neighboring cells needs to be at least -6 dB.l PRS is a pseudo-random QPSK sequence similar to CRS; PRS pattern: l Diagonal pattern with time varying frequency shift. l 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 | 194
  • 194. Uplink (UTDOA) l UTDOA = Uplink Time Difference of Arrival l 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 Location Server and estimates the UE position November 2012 | LTE Introduction | 195
  • 195. What is Self Organizing Networks, SON? l SON = Self-Organizing Networks, methods for automatic configuration and optimization of the network l 3 components: l Self-Configuration: l basic setup: IP address configuration, association with a Gateway, software download,… l Initial radio configuration: neighbour list configuration,… l Self-Optimization: l Neighbour list optimization, coverage/capacity optimization,… l Self-Healing: l Failure detection/localization,… November 2012 | LTE Introduction | 196
  • 196. Motivation for SONHeterogeneous Networks: No way without SON Source: Deutsche Telekom November 2012 | LTE Introduction | 197
  • 197. Overview SONConnect eNB eNB failure November 2012 | LTE Introduction | 198
  • 198. Architecture Centralized SON Distributed SON Centralized O&M SON O&M O&M SON SON Hybrid SON eNB eNB SON SON November 2012 | LTE Introduction | 199
  • 199. Energy Savingsl Match Network Capacitiy to the required traffic l Switch on / off cell on demandl Vodafone contribution on NGMN: November 2012 | LTE Introduction | 200
  • 200. Self Healingl Automatic detection of failures (Sleeping Cells) l Usually detected by performance statistics l Unreliable, because statistics sometimes fluctuate largelyl Cell Outage Compensation l Recovery actions – Fallback to previous SW – Switching to backup units for HW l Self optimization of the surrounding NW November 2012 | LTE Introduction | 201
  • 201. Automatic Configuration of Physical Cell IDRelease 8l Automatic configuration of new deployed eNodeBs l 504 Physical Cell IDs are supportedl Selection of Physical Cell ID must be l Collision free – The ID is unique in the area the cell covers l Confusion free – A cell shall not have neighboring cells with identical IDsl Definitely a must for Femto-Cells (HeNBs)l Centralized or Distributed Architecture November 2012 | LTE Introduction | 202
  • 202. Mobility Robustness Optimization (MRO)Release 9l Manually setting of HO parameters l Time consuming → Often neglected l Optimal settings may depend on momentary radio conditions – Difficult to control manuallyl Incorrect HO parameter setting may lead to l Non-optimal use of network resources – Unnecessary handovers – Prolonged connection to a non-optimal cell l HO failures – Degradation of the service performance l Radio Link failures – Combined impact on user experience and network performance – The main objective of MRO is to reduce RLF November 2012 | LTE Introduction | 203
  • 203. Coverage and Capacity Optimization Pilot pollution (Interference) Cell edge performance Trade-Off between coverage and capacity  Coverage has priority Measurement by Network: eNodeB l Call drop rates → Indication of eNodeB insufficient coverage l Traffic counters eNodeB → Capacity problems Detection of unintended coverage holes November 2012 | LTE Introduction | 204
  • 204. Mobility Load Balancing (MLB) OptimizationRelease 9 November 2012 | LTE Introduction | 205
  • 205. IMT-Advanced Requirementsl 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,l Compatibility of services within IMT and with fixed networks,l Capability of interworking with other radio access systems,l High quality mobile services,l User equipment suitable for worldwide use,l User-friendly applications, services and equipment,l Worldwide roaming capability; andl Enhanced peak data rates to support advanced services and applications, l 100 Mbit/s for high and l 1 Gbit/s for low mobility were established as targets for research, November 2012 | LTE Introduction | 206
  • 206. 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 Urban In-Building Picocell Microcell Macrocell Basic Terminal PDA Terminal Audio/Visual Terminall 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 technologiesl 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 | 207
  • 207. IMT Spectrum MHz MHzNext possible spectrumallocation at WRC 2015! MHz MHz November 2012 | LTE Introduction | 208
  • 208. 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 | 209
  • 209. IMT – International Mobile Communicationl IMT-2000 l Was the framework for the third Generation mobile communication systems, i.e. 3GPP-UMTS and 3GPP2-C2K l Focus was on high performance transmission schemes: Link Level Efficiency l 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).l IMT-Advanced l Basis of (really) broadband mobile communication l Focus on System Level Efficiency (e.g. cognitive network systems) l Vision 2010 – 2015 November 2012 | LTE Introduction | 210
  • 210. System level efficiencyl Todays mobile communication networks use static frequency allocation l Network planning l Adaptation to traffic load over cell boarder not possiblel Dynamic spectrum allocation to increase system efficiency l Radio resource management to configure the occupied bandwidth of each cell l Dynamic management for inter-cell interference reduction l Cognitive networks (self organizing networks SON) which adjust automatically to traffic load and interference conditions. l Application oriented source and channel coding l Typically, source and channel coding are separated, i.e. MPEG and convolutional coding. Joint Source & Channel Coding (JSCC) promises better efficiencyl Base stations are on 24/7– but why? l Basisstations/Relaystations operate in „sleep“ or „off“ modes l Enhancements of interference situations and energy consumptionl Too many interfaces reduce the throughput l Reducing the amount of components in the network structurel Heterogenuous networks l Usage of various radio access technologies of same core network November 2012 | LTE Introduction | 211
  • 211. LTE-AdvancedPossible technology features Relaying Wider bandwidth technology support Enhanced MIMO Cooperative schemes for DL and UL base stations Interference management Cognitive radio methods methods Radio network evolution Further enhanced MBMS November 2012 | LTE Introduction | 212
  • 212. Bandwidth extension with Carrier aggregation November 2012 | LTE Introduction | 213
  • 213. LTE-AdvancedCarrier Aggregation Component carrier CC Contiguous carrier aggregation Non-contiguous carrier aggregation November 2012 | LTE Introduction | 214
  • 214. Aggregationl Contiguous l Intra-Bandl Non-Contiguous l Intra (Single) -Band l Inter (Multi) -Bandl Combination l Up to 5 Rel-8 CC and 100 MHz l Theoretically all CC-BW combinations possible (e.g. 5+10+20 etc) November 2012 | LTE Introduction | 215
  • 215. Motivationl 1) Higher data rate through more spectrum allocation l to fulfill 4G requirements l 1 Gbit/s in downlink (up to 5 component carriers, up to 100 MHz) l Other methods (spectral efficiency etc.) already exploited or not relevantl 2) Exploit the total (combined) BW assigned in form of separated bands l scattered spectrum November 2012 | LTE Introduction | 216
  • 216. Carrier aggregation (CA)General commentsl 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 non- Intra-band contiguous Frequency band A Frequency band B contiguous component carrier aggregation (intra-band) and inter-band carrier aggregation. Component Carrier (CC) l Different bandwidths per Intra-band non-contiguous Frequency band A Frequency band B component carrier (CC) are possible. l Each CC limited to a max. of 110 RB using the 3GPP Rel-8 numerology 2012 © by Rohde&Schwarz (max. 5 carriers, 20 MHz each). Inter-bandl Motivation. Frequency band A Frequency band B l Higher peak data rates to meet IMT-Advanced requirements. l NW operators: spectrum aggregation, enabling Heterogonous Networks. November 2012 | LTE Introduction | 217
  • 217. Overviewl 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 Cell 1 Cell 2 – Backwards compatibility l CC-Set is UE specific – Registration  Primary (P)CC UE1 UE4 UE3 U3 UE4 U2 – Additional BW  Secondary (S)CC-s 1-4 l CC2 Network perspective CC1 – Same single RLC-connection for one UE (independent on the CC-s) UE1 UE2 – Many CC (starting at MAC scheduler) CC2 CC1 UE3 operating the UE l For TDD – Same UL/DL configuration for all CC-s UE4 November 2012 | LTE Introduction | 219
  • 218. 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 Uplink SCC SCC SCC PCC SCC PCC SCC SCC SCC SCC 2012 © by Rohde&Schwarz PDSCH and PDCCH PUSCH and PUCCH PDSCH, PDCCH is optional PUSCH only November 2012 | LTE Introduction | 220
  • 219. LTE-AdvancedCarrier Aggregation – Initial Deploymentl Initial LTE-Advanced deployments will likely be limited to the use of two component carrier.l The below are focus scenarios identified by 3GPP RAN4. November 2012 | LTE Introduction | 221
  • 220. Bandwidth  BWChannel(1)  BWChannel( 2)  0.1 BWChannel(1)  BWChannel( 2)  Nominal channel spacing   0.3 MHzl General   0.6   – Up to 5 CC – Up to 100 RB-s pro CC – Up to 500 RB-s aggregatedl Aggregated transmission bandwidth – Sum of aggregated channel bandwidths – Illustration for Intra band contiguous – Channel raster 300 kHzl Bandwidth classes – UE Capability November 2012 | LTE Introduction | 222
  • 221. Bands / Band-Combinations (I)l E-UTRA CA Band l Band / Band-Combinatios specified in RAN4 for CA scenarios l Already 4 CA Bands specified – For inter frequency  bands without practical interest to guarantee quick progress of the work November 2012 | LTE Introduction | 223
  • 222. 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 Rel- 10 November 2012 | LTE Introduction | 224
  • 223. Carrier aggregation - configurationsl 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 | 225
  • 224. UE categories for Rel-10 NEW!UE categories 6…8 (DL and UL) Maximum number Maximum number of bits Maximum number of UE of DL-SCH transport Total number of of a DL-SCH transport supported layers for Category block bits received soft channel bits block received within a TTI spatial multiplexing in DL within a TTI … … … … … 149776 (4 layers) Category 6 301504 3654144 2 or 4 75376 (2 layers) 149776 (4 layers) Category 7 301504 3654144 2 or 4 75376 (2 layers) Category 8 2998560 299856 35982720 8 Maximum number ~3 Gbps peak Maximum number Support of UL-SCH Total layer 2 DL data rate of bits of an UL-SCH for UE transport buffer size for 8x8 MIMO transport block 64Q Category block bits [bytes] transmitted within a AM transmitted TTI in UL within a TTI … … … … … 3 300 000 Category 6 51024 51024 No 3 800 000 Category 7 102048 51024 No 42 200 000 Category 8 1497760 149776 Yes ~1.5 Gbps peak November 2012 | LTE Introduction | 226 UL data rate, 4x4 MIMO
  • 225. Deployment scenarios3) Improve coveragel #1: Contiguous frequency aggregation F1 F2 – Co-located & Same coverage – Same fl #2: Discontiguous frequency aggregation – Co-located & Similar coverage – Different fl #3: Discontiguous frequency aggregation – Co-Located & Different coverage – Different f – Antenna direction for CC2 to cover blank spotsl #4: Remote radio heads – 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?l #5:Frequency-selective repeaters – Combination #2 & #4 – Different f – Extend the coverage of the 2nd CC with Relays November 2012 | LTE Introduction | 227
  • 226. Physical channel arrangement in downlink Each component carrier transmits P- Each component SCH and S-SCH, carrier transmits Like Rel.8 PBCH, Like Rel.8 November 2012 | LTE Introduction | 228
  • 227. LTE-AdvancedCarrier Aggregation – Scheduling l There is one transport block (in Contiguous Non-Contiguous spectrum allocation absence of spatial multiplexing) RLC transmission buffer and one HARQ entity per Dynamic scheduled component carrier switching (from the UE perspective), l A UE may receive multiple Channel coding Channel coding Channel coding Channel coding component carriers simultaneously, HARQ HARQ HARQ HARQ l Two different approaches are Data Data Data Data discussed how to inform the UE mod. mod. mod. mod. about the scheduling for each band, Mapping Mapping Mapping Mapping l Separate PDCCH for each carrier, l Common PDCCH for multiple carrier, e.g. 20 MHz [frequency in MHz] November 2012 | LTE Introduction | 229
  • 228. LTE-AdvancedCarrier Aggregation – Scheduling Non-Contiguous spectrum allocation Contiguous RLC transmission buffer Dynamic switching Channel Channel Channel Channel coding coding coding coding Each component HARQ HARQ HARQ HARQ Carrier may use its Data Data Data Data mod. mod. mod. mod. own AMC, Mapping Mapping Mapping Mapping = modulation + coding e.g. 20 MHz scheme [frequency in MHz] November 2012 | LTE Introduction | 230
  • 229. Carrier Aggregation – Architecture downlink 1 UE using carrier aggregation Radio Bearers Radio Bearers ROHC ... ROHC ROHC ... ROHC ROHC ROHCPDCP ... PDCP Security ... Security Security ... Security Security Security Segm. Segm. Segm. Segm. Segm. Segm. Segm. Segm. ... ... ... RLC ... RLC ARQ etc ARQ etc ARQ etc ARQ etc ARQ etc ARQ etc CCCH BCCH PCCH CCCH MCCH MTCH Logical Channels Logical Channels Unicast Scheduling / Priority Handling MBMS Scheduling Scheduling / Priority Handling Multiplexing UE1 ... Multiplexing UEn Multiplexing MultiplexingMAC MAC HARQ ... HARQ HARQ ... HARQ HARQ ... HARQ Transport Channels Transport Channels BCH PCH MCH UL-SCH UL-SCH DL-SCH DL-SCH DL-SCH DL-SCH on CC1 on CCz on CC1 on CCx on CC1 on CCy 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 | 231
  • 230. Common or separate PDCCH per Component Carrier?l No cross-carrier scheduling. up to 3 (4) symbols per subframe 1 subframe = 1 ms l PDCCH on a component carrier Time 1 slot = 0.5 ms assigns PDSCH resources on the Frequency same component carrier (and PDCCH PDCCH PUSCH resources on a single PDSCH PDSCH linked UL component carrier). l Reuse of Rel-8 PDCCH structure PDCCH (same coding, same CCE-based PCC PDSCH PDSCH PDCCH resource mapping) and DCI formats.l Cross-carrier scheduling. l PDCCH on a component carrier can assign PDSCH or PUSCH PDSCH PDSCH PDCCH PDCCH resources in one of multiple component carriers using the carrier indicator field. l Rel-8 DCI formats extended with 3 bit carrier indicator field. No cross-carrier Cross-carrier l Reusing Rel-8 PDCCH structure (same scheduling scheduling coding, same CCE-based resource mapping). November 2012 | LTE Introduction | 232
  • 231. 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 | 233
  • 232. Cross-carrier schedulingl Main motivation for cross carrier scheduling: Interference management for HetNet (eICIC); load balancing.l Cross carrier scheduling is optional to a UE. l Activated by RRC signaling, if not activated no CFI is present. l Component carriers are numbered, Primary Component Carrier (PCC) is always cell index 0. l Scheduling on a component carrier is only possible from ONE component, independent if cross-carrier scheduling is ON or OFF: PCFICH PDCCH PDCCH PDCCH PDSCH start signaled by RRC PDSCH … not possible, transmission Component Component can only be Component Carrier #1 Carrier #2 scheduled by Carrier #5 one CC l If cross carrier-scheduling active, UE needs to be informed about PDSCH start on component carrier  RRC signaling. November 2012 | LTE Introduction | 234
  • 233. 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 f fComponent carrier 1 Component carrier 2 Component carrier N November 2012 | LTE Introduction | 235
  • 234. PDSCH start fieldExample: 1 Resource blockOf a component carrier R R RPCFICH PCFICH PCFICHe.g. PCC e.g. SCC PDCCH Secondary componentPrimary component carriercarrier PDSCH start field indicates positionIn 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 | 236
  • 235. Component Carrier – RACH configuration Downlink Asymmetric carrier Aggregation possible, e.g. DL more CC than UL Uplink All CC use same RACH preambleEach CC has its own RACH Network responds on all CCs Only 1 CC contains RACH November 2012 | LTE Introduction | 237
  • 236. Symmetry l Component Carrier l DL-UL – However position of DC not known to System l Number of CC Simulator – TDD: DL = UL – FDD: DL >= UL l Bandwidth l Both November 2012 | LTE Introduction | 238
  • 237. Addition, modification, release of additional CCl RRCConnectionReconfiguration Message contains new Rel- 10 information element: DL: bandwidth, antennas, MBSFN subframe configuration, PHICH configuration, PDSCH configuration, TDD config (if TD-LTE SCell) UL: bandwidth, carrier frequency, additional spectrum emission, P-Max, power control info, uplink channel configuration (PRACH, PUSCH) UE-specifc information; DL: cross-carrier scheduling, CSI-RS configuration, PDSCH UL: PUSCH, uplink power control, CQI, SRS November 2012 | LTE Introduction | 239
  • 238. Default EPS bearer setup (3GPP LTE Rel-8) UE EUTRAN Initial access and RRC connection establishment attach request and PDN connectivity request Additional information Authentication being submitted by a 3GPP Rel-10 device… NAS security UE capability procedure AS security RRC connection reconfiguration Attach accept and default EPS bearer context request Default EPS bearer context accept November 2012 | LTE Introduction | 240
  • 239. UE capability information transfer3GPP Rel-10 add on’s Not all combinations are allowed!l New IE’s within the for a 3GPP Rel-10 device: Carrier aggregation capabilities are signaled separately for DL, UL. What frequency bands, band combination (CA and MIMO capabilities, inter-band, intra-band contiguous and non-contiguous, bandwidth class does the device support? 2012 © by Rohde&Schwarz ! November 2012 | LTE Introduction | 241
  • 240. Carrier Aggregation - Activationl A new MAC control element for Component Carrier Management is defined containing at least the activation respectively deactivation command for the secondary DL component carriers configured for a UE. The new MAC CE is identified by a unique LCIDll For actual deactivation and activation signalling for the DL SCCs, the MAC CE for CC Management includes a 4/5-bit bitmap where each bit is representing one of the DL CCs that can be configured in the UE. A bit set to 1 denotes activation of the corresponding DL CC, a bit set to 0 respectively denotes deactivationl New timer for implicit CC deactivationl CCs are "just" additional resources. UL scheduling will assume we do not have different QOS (delay/loss) on different CCs November 2012 | LTE Introduction | 242
  • 241. Carrier Aggregationl The transmission mode is not constrained to be the same on all CCs scheduled for a UEl A single UE-specific UL CC is configured semi-statically for carrying PUCCH A/N, SR, and periodic CSI from a UEl Frequency hopping is not supported simultaneously with non-contiguous PUSCH resource allocationl UCI cannot be carried on more than one PUSCH in a given subframe. November 2012 | LTE Introduction | 243
  • 242. Carrier Aggregationl 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 UCI can be transmitted on either PUCCH or PUSCH with a dependency on the situation that needs to be further discussed l 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 | 244
  • 243. UE Architecturesl Possible TX architectures l Same / Different antenna (connectors) for each CC l D1/D2 could be switched to support CA or UL MIMO November 2012 | LTE Introduction | 245
  • 244. LTE–Advanced solutions from R&SR&S® SMU200 Vector Signal Generator November 2012 | LTE Introduction | 246
  • 245. LTE–Advanced solutions from R&SR&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 20 MHz E-UTRA carrier 2 -70 E-UTRA carrier 2 EXT fc,E-UTRA carrier 2 = 2135 MHz fc,E-UTRA carrier 2 = 2205 MHz3DB -80 -90 -100 -110 -120 Center 2.17 GHz 10 MHz/ Span 100 MHz LTE-Advanced – An introduction November 2012 | LTE Introduction | 247 Date: 8.OCT.2009 14:13:24 Roessler | October 2009 | 247 A.
  • 246. Enhanced MIMO schemesl Increased number of layers: l Up to 8x8 MIMO in downlink. l Up to 4x4 MIMO in uplink.l 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 UE- specific 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 | 248
  • 247. Downlink reference signals in LTE-Advancedl Define two types of RS, l RS and data are subject to the same l RS targeting PDSCH demodulation, pre-coding operation, l RS targeting CSI generation (for l complementary use of Rel-8 CRS by CQI/PMI/RI/etc reporting when the UE is not precluded, needed), l RS targeting CSI generation (forl RS targeting PDSCH demodulation LTE-A operation) are (for LTE-Advanced operation) are l Cell specific and sparse in frequency l UE specific and time – Transmitted only in scheduled RBs and l Rel-8 transmission schemes using the corresponding layers Rel-8 cell-specific and/or UE- – Different layers can target the same or specific RS still supported, different UEs – Design principle is an extension of the concept of Rel-8 UE-specific RS (used for beamforming) to multiple layersDetails on UE-specific RS pattern, location, etc are FFS l RS on different layers are mutually orthogonal, November 2012 | LTE Introduction | 249
  • 248. Cell specific Reference Signals vs. DM-RS LTE Rel.8 LTE-Advanced (Rel.10) CRS0 DM-RS0 CRS0 + CSI-RS0 s1 s1 s2 s2 Pre- Pre- ........ ........ coding coding sN sN Cell specific DM-RSN Cell specific Reference signalsN reference signalsN + Channel status information reference signals 0l 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 | 250
  • 249. Ref. signal mapping: Rel.8 vs. LTE-Advanced l Example: LTE (Release 8) LTE-A (Release 10) l 2 antenna ports, antenna port 0,0 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 CSI-RS configuration 8. l PDCCH (control) allocated in the 1 0x x x x first 2 OFDM symbols. R E L E A S E x x x x l CRS sent on all RBs; DTX sent for the CRS of 2nd antennax x x x port. x x x x l DM-RS sent only for scheduled 8x x x x RBs on all antennas; each set R E L E A S E x x x x coded differently between the two layers.x x x x x x x x l CSI-RS punctures Rel. 8 data; sent periodically over allottedPDSCH PDCCH CRS DM-RS CSI-RS REs (not more than twice per frame) November 2012 | LTE Introduction | 251
  • 250. DL MIMOExtension up to 8x8 Codeword to layer mapping for spatial multiplexingl Max number of transport blocks: 2 Number Number Codeword-to-layer mappingl Number of MCS fields of layers of code words i  0,1, M symb  1 layer l one for each transport block x ( 0) (i)  d ( 0) (2i)l ACK/NACK feedback x (1) (i)  d ( 0) (2i  1) l 1 bit per transport block for evaluation 5 2 M symb  M symb 2  M symb 3 layer ( 0) (1) x (i)  d (3i ) ( 2) (1) as a baseline x (3) (i )  d (1) (3i  1)l Closed-loop precoding supported x ( 4) (i)  d (1) (3i  2) l Rely on precoded dedicated x ( 0) (i )  d ( 0) (3i) x (1) (i )  d ( 0) (3i  1) demodulation RS (decision on DL RS) x ( 2) (i)  d ( 0) (3i  2)l M symb  M symb 3  M symb 3 layer ( 0) (1) 6 2 Conclusion on the codeword-to- x (3) (i)  d (1) (3i) layer mapping: x ( 4) (i)  d (1) (3i  1) x (5) (i )  d (1) (3i  2) l DL spatial multiplexing of up to eight x ( 0) (i )  d ( 0) (3i) layers is considered for LTE-Advanced, x (1) (i )  d ( 0) (3i  1) x ( 2) (i)  d ( 0) (3i  2) l Up to 4 layers, reuse LTE codeword-to- 7 2 M symb  M symb 3  M symb 4 layer ( 0) (1) layer mapping, x (3) (i )  d (1) (4i ) x ( 4) (i )  d (1) (4i  1) l Above 4 layers mapping – see table x (5) (i )  d (1) (4i  2) x ( 6) (i )  d (1) (4i  3)l Discussion on control signaling x ( 0) (i )  d ( 0) (4i ) x (1) (i )  d ( 0) (4i  1) details ongoing x ( 2) (i )  d ( 0) (4i  2) x (3) (i )  d ( 0) (4i  3) 8 2 M symb  M symb 4  M symb 4 layer ( 0) (1) 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) November 2012 | LTE Introduction | 252
  • 251. MIMO – layer and codeword 101Codeword 1: 101111000011101 Codeword 1: 100 111000011101 011 ACK 000Codeword 2: 111 Codeword 2:010101010011 010101010011 001 111 Up to 8 times ACK the data -> Receiver only 8 layers Sends 2 ACK/NACKs November 2012 | LTE Introduction | 253
  • 252. Scheduling of Transmission Mode 9 (TM9)l NEW DCI format 2C with 3GPP Rel-10. l Used to schedule transmission mode 9 (TM9), which is spatial multiplexing with DM-RS support of up to 8 layers (multi-layer transmission). – DM-RS scrambling and number of layers are jointly signaled in a 3-bit field.l DCI format 2C. – Carrier indicator [3 bit]. One Codeword: Codeword 0 enabled, Two Codewords: Codeword 0 enabled, – Resource allocation header [1 bit] Codeword 1 disabled Codeword 1 enabled Value Message Value Message – Resource Allocation Type 0 and 1. 0 1 layer, port 7, n =0 0 2 layers, ports 7-8, nSCID=0 – TPC command for PUCCH [2 bit]. SCID 1 1 layer, port 7, nSCID=1 1 2 layers, ports 7-8, nSCID=1 – Downlink Assignment Index1) [2 bit]. 2 1 layer, port 8, nSCID=0 2 3 layers, ports 7-9 – HARQ process number 3 1 layer, port 8, nSCID=1 3 4 layers, ports 7-10 [3 bit (FDD), 4 bit (TDD)]. 4 2 layers, ports 7-8 4 5 layers, ports 7-11 – Antenna ports, scrambling identiy 5 3 layers, ports 7-9 5 6 layers, ports 7-12 and # of layers; see table [3 bit]. 6 4 layers, ports 7-10 6 7 layers, ports 7-13 – SRS request1) [0-1 bit]. 7 Reserved 7 8 layers, ports 7-14 – MCS, new data indicator, RV for 2 transport block [each 5 bit]. 1) TDD only November 2012 | LTE Introduction | 254
  • 253. Uplink MIMO Extension up to 4x4l Rel-8 LTE. l UEs must have 2 antennas for reception. l But only 1 amplifier for transmission is available (costs/complexity). l 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 UL spatial multiplexing of up to 4 layers is considered for LTE-Advanced. l SRS enables link and SU-MIMO adaptation.l Number of receive antennas are receiver-implementation specific. l At least two receive antennas is assumed on the terminal side. November 2012 | LTE Introduction | 255
  • 254. UL MIMO – signal generation in uplinkSimilar to Rel.8 Downlink:codewords layers antenna ports Modulation Transform Resource element SC-FDMA Scrambling mapper mapper precoder signal gen. Layer Precoding mapper Modulation Transform Resource element SC-FDMA Scrambling mapper mapper precoder signal gen.Avoidperiodic bit QPSK Up to DFT,sequence 16-QAM 4 layer as in Rel 8, 64-QAM but non- contiguous allocation possible November 2012 | LTE Introduction | 256
  • 255. UL MIMO – layers and codewords Number of layers Number of codewords Codeword-to-layer mapping i  0,1,...,M symb  1 layer 1 1 x (0) (i)  d (0) (i) M symb  M symb layer ( 0) x (0) (i)  d (0) (2i ) 2 1 x (1) (i)  d (0) (2i  1) M symb  M symb 2 layer ( 0) x (0) (i)  d (0) (i) 2 2 M symb  M symb  M symb layer ( 0) (1) x (i)  d (i) (1) (1) x (0) (i)  d (0) (i) 3 2 x (1) (i)  d (1) (2i ) M symb  M symb  M symb 2 layer ( 0) (1) x ( 2) (i)  d (1) (2i  1) x (0) (i)  d (0) (2i ) x (1) (i)  d (0) (2i  1) 4 2 M symb  M symb 2  M symb 2 layer ( 0) (1) x ( 2) (i)  d (1) (2i ) x (3) (i)  d (1) (2i  1)Up to 4 Layers 2 codewords(Rel.11) November 2012 | LTE Introduction | 257
  • 256. UL MIMO scheduling – DCI format 4 NEW!l Carrier indicator [0-3 bit]. l Downlink Assignment Index [2 bit].l Resource Block Assignment: l TDD only, UL-DL config. 1-6. l [bits] for Resource Allocation Type 0 l CSI request [1 or 2 bit]. l     log ( N UL ( N UL  1) / 2)  2 RB RB    2 bit for cells with more than two cells in the DL (carrier aggregation). l [bits] for Resource Allocation Type 1. l SRS request [2 bit]. l Resource Allocation Type [1    N RB / P  1  UL log 2       bit].    4    l Transport Block 1.l TPC command for PUSCH [2 l MCS, RV [5 bit]. bit]. l New data indicator [1 bit].l Cyclic shift for DM RS and l Transport Block 2. OCC index [2 bit]. l MCS, RV [5 bit].l UL index [2 bit]. l New data indicator [1 bit]. l TDD only for UL-DL l Precoding information. configuration 0. November 2012 | LTE Introduction | 258
  • 257. LTE-AdvancedEnhanced uplink SC-FDMAl The uplink transmission scheme remains SC-FDMA.l The transmission of the physical uplink shared channel (PUSCH) uses DFT precoding.l Two enhancements: l Control-data decoupling l Non-contiguous data transmission November 2012 | LTE Introduction | 259
  • 258. Physical channel arrangement - uplink Simultaneous transmission ofClustered-DFTS-OFDM PUCCH and PUSCH from= Clustered DFT spread the same UE is supportedOFDM.Non-contiguous resource block allocation => will cause higherCrest factor at UE side November 2012 | LTE Introduction | 260
  • 259. LTE-AdvancedEnhanced uplink SC-FDMA Unused subcarriers November 2012 | LTE Introduction | 261
  • 260. LTE-AdvancedEnhanced 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 | 262
  • 261. Simultaneous PUSCH-PUCCH transmission, multi-cluster transmissionl Remember, only one UL carrier in 3GPP Release 10; scenarios: l Feature support is indicated by PhyLayerParameters-v1020 IE*). PUCCH and PUCCH and fully allocated PUSCH allocated PUSCH f [MHz] f [MHz] PUCCH PUSCH partially PUCCH and partially allocated PUSCH allocated PUSCH f [MHz] f [MHz] *) see 3GPP TS 36.331 RRC Protocol Specification November 2012 | LTE Introduction | 263
  • 262. 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 | 264
  • 263. Resource Allocation types in the uplinkl Uplink Resource Allocation Type 0. l Contiguous allocation as today in 3GPP Release 8.l Uplink Resource Allocation Type 1. l UL bandwidth is divided into two sets of Resource Blocks (RB). l Each set has a number of Resource Block Groups (RBG) of size P. l Combinatorial index r, indicates RBG starting and ending index for both set of RB (s0, s1-1 | s2, s3-1. System RBG Bandwidth Size (P) M 1 N  si si i 0 M 1 r  i 0 M i 1  si  N , si  si 1 ≤10 11 – 26 1 2 – M = 4, N is bandwidth dependent, N  N RB / P  UL  1 27 – 63 64 – 110 3 4 November 2012 | LTE Introduction | 265
  • 264. Multi-cluster allocationUplink Resource Allocation Type 1l Example: LTE 10 MHz (50 RB), P = 3 leads to 17 RBG. l Combinatorial index r indicates RBG starting indices for RB set #1 (s0, s1-1, defining cluster #1) and RB set #2 (s2, s3-1, defining cluster #2). l Range for s0, s1, s2, s3 for 10 MHz (50 RB): 1 to 18 (see previous slide). l Applied rule: s0 < s1 < s2 < s3 (see previous slide). l Example: s0=2, s1=9, s2=10, s3=11: “START” “END” “START” (s0) (s1-1) (s2) “END” (s3-1) RBG#1 RBG#3 RBG#5 RBG#7 RBG#9 RBG#11 RBG#13 RBG#15 RBG#0 RBG#2 RBG#4 RBG#6 RBG#8 RBG#10 RBG#12 RBG#14 RBG#16 Cluster #1 Cluster #2 November 2012 | LTE Introduction | 266
  • 265. 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 | 267
  • 266. Significant step towards 4G: Relaying ? Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008 November 2012 | LTE Introduction | 268
  • 267. 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 | 269
  • 268. L1/L2 Relaying approach Source: TTA‘s workshop for the future of IMT-Advanced technologies, June 2008 November 2012 | LTE Introduction | 270
  • 269. LTE-AdvancedRelayingl LTE-Advanced extends LTE Release 8 with support for relaying in order to enhance coverage and capacityl Classification of relays based on l implemented protocol knowledge… – Layer 1 (repeater) – Higher Layer (decode and forward or even mobility management, session set-up, handover) l … and whether the relay has its own cell identity – Type 1 relay effectively creates its own cell (own ID and own synchronization and reference channels – Type 2 relay will not have its own Cell_ID Type 2 Type 1 November 2012 | LTE Introduction | 271
  • 270. LTE-Advanced: RelayingThe relay node (RN) is wirelessly connected to a donor cell of adonor eNB via the Un interface, and UEs connect to the RN viathe Uu interface Uu Un EPC UE RN eNB Inband: 2 links operate in the same frequency Outband: 2 links operate in different frequencies November 2012 | LTE Introduction | 272
  • 271. Co-operative Relaying Approachesl Receiver in MS (or BS) gains from both, the signal origin and the relay stationl Co-operative Relaying creates virtual MIMO • RSs are „decode-and-forward“ devices November 2012 | LTE Introduction | 273
  • 272. LTE-AdvancedCoordinated Multipoint Tx/Rx (CoMP) CoMP Coordination between cells November 2012 | LTE Introduction | 276
  • 273. Coordinated Multipoint, CoMP Controller Controller UE estimates Various DL CSI + feedback feedback Info about CoMP, UE perform signal processing Controller CoMPEach eNB Info UE estimates variousEstimates Uplink Downlink + feedback CSI No info about CoMP feedback at UE November 2012 | LTE Introduction | 277
  • 274. LTE-A: PCFICH indicating PDCCH size PCFICH content in LTE R-8 PCFICH content in LTE-A Subframe where Number of OFDM symbols for PDCCH when PCFICH is sent N RB  10 DL N RB  10 DL PCFICH can Subframe 1 and 6 1, 2 2 indicate up to 4 in TDD mode OFDM symbols Subframe 0 in FDD 1, 2, 3 2, 3, 4 mode for used by PDCCH PDSCH PBCH PDCCH S-SCH PCFICH P-SCH Time Frequency November 2012 | LTE Introduction | 278
  • 275. LTE-A: Multiple Access MAC layer concept Transport block 1 Transport block K Segmentation Segmentation FEC FEC FEC FEC Non-frequency adaptive Frequency adaptive Resource scheduler Packet processing Mapping on dispersed chunks Mapping on frequency optimal chunks Bit interleaved coded modulation Bit interleaved coded modulationQuasi cyclic block low density partity check Quasi cyclic block low density partity check Antenna summation, linear precoding IFFT + CP insertion RF generation November 2012 | LTE Introduction | 279
  • 276. LTE-Advanced: C-Plane latency Connected 10ms Dormant Active Already fullfills ITU 50ms Requirement with Rel.8, Idle but ideas to speed up:•Combined RRC Connection Request and NAS Service Request•Reduced processing delays in network nodes•Reduced RACH scheduling period: 10ms to 5ms Shorter PUCCH cycle: requests are sent faster Contention based uplink: UE sends data without previous request November 2012 | LTE Introduction | 280
  • 277. LTE Registration – R8 to R10…. UE SS incl. security activation RRC ConnectionnRequest RRC ConnectionnSetup RRC ConnectionSetupComplete contains NAS ATTACH REQUESTNAS PDN CONNECTIVITY REQUEST NAS : AUTHENTICATION REQUESTRegistration NAS : AUTHENTICATION RESPONSEAlready in RRC NAS : SECURITY MODE COMMANDConnection NAS : SECURITY MODE COMMAND COMPLETERequest RRC : SECURITY MODE COMMAND RRC : SECURITY MODE COMMAND COMPLETE RRC ConnectionReconfiguration NAS ATTACH ACCEPT contains NAS : ACTIVATE DEFAULT EPS BEARER CONTEXT REQ RRC ConnectionReconfigurationComplete NAS : ATTACH COMPLETE NAS : ACTIVATE DEFAULT EPS BEARER CONTEXT ACCEPT November 2012 | LTE Introduction | 281
  • 278. 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 | 282
  • 279. ODMA – some ideas… BTSMobile devices behave asrelay station November 2012 | LTE Introduction | 283
  • 280. 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 | 284
  • 281. Cooperative communication Multi-access Independent fading pathsVirtual Higher signalingAntenna System complexityArray Cell edge coverage Group mobility November 2012 | LTE Introduction | 285
  • 282. Mobile going GREEN November 2012 | LTE Introduction | 286
  • 283. Ubiquitous communication November 2012 | LTE Introduction | 287
  • 284. There will be enough topics for future trainings Thank you for your attention! Comments and questions welcome! November 2012 | LTE Introduction | 288