PHYSICAL LAYER for DIGITAL TELEVISION ATSC 3.0 STANDARD based on SC – FDMA .

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Described a proposition for Physical Layer of Next generation broadcast television (NGBT) and ATSC 3.0 Television standard. The Proposed system is back compatible with existing ATSC standards A/53, A/153 and based on improved version of SC-FDMA modulation.

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PHYSICAL LAYER for DIGITAL TELEVISION ATSC 3.0 STANDARD based on SC – FDMA .

  1. 1. PHYSICAL LAYER for DIGITAL TELEVISION ATSC 0.3 STANDARD based on SC – FDMA Technology 6/30/2013 VIO Concept LTD. 1
  2. 2. 6/30/2013 VIO Concept LTD. 2 (ATSC-3.0)
  3. 3. 6/30/2013 VIO Concept LTD. 3
  4. 4. NEW TECHNOGIES • Any new standard should not only rely on existing technologies – Need balanced mix of proven technologies + new challenges (technologies pushing limit) – We should explore and choose the right mix of novel technologies for new standard. • 1024QAM • SC-FDMA • 32VSB 6/30/2013 VIO Concept LTD. 4
  5. 5. Introduction to SC-FDMA • SC-FDMA can be regarded as the discrete Fourier transform (DFT)-spread OFDMA, where time domain data symbols are transformed into the frequency domain by DFT before going through OFDMA modulation. The orthogonality of the users steams from the fact that each user occupies different subcarriers in the frequency domain, similar to the case of OFDMA. Because the overall transmit signal is a single carrier signal, PAPR is inherently low compared to the case of OFDMA which produces a multicarrier signal. SC-FDMA uses the cyclic prefix like OFDM. • SC-FDMA has the same immunity to multipath distortion as OFDM and the same spectrum of the transmitted signal. Because PAR of SC-FDMA is only ~7.5 dB and PAR of OFDM is about 10~12.5 dB, the SC-FDMA system needs in significant lower power of the RF transmitter. • Unfortunately, SC-FDMA comprises DFT and IDFT cores these are high complexity devices. For processing of N-point DFT N^2 operations are required. For N-point FFT, only N*log2(N) operations are required. This is the reason why SC-FDMA is used only in narrowband LTE uplink. • 6/30/2013 VIO Concept LTD. 5
  6. 6. SC-FDMA SYSTEM 6/30/2013 VIO Concept LTD. 6
  7. 7. Introduction to improved SC- FDMA • In a new SC-FDMA system information symbols come to Transmitter, which generates a single carrier signal with the spectrum and peak-to- average ratio which depend of the defined wavelet form. This signal comes to M-point FFT core. After a FFT transform and subcarrier mapping the signal arises to the digital filter. The filtered signal is added to a number of pilot signals. After M-point IFFT transform in the SC- FDMA signal inserts a cyclic prefix. Because of this cyclic prefix the SC- FDMA signal has the same an immunity to multipath distortion as OFDM signal . • The PAR of a new SC-FDMA signal is about 5~7.5 dB, that's significantly less than PAR of OFDM (10~12 dB) and known SC-FDMA (7~8.5dB). • Because of absence of DFT the improved SC-FDMA system can be used for transmission of broadband signals like TV or broadcast satellite. Note that, in improved SC-FDMA system, both FFT and IFFT transforms have the same order(M) and may use the same physical core. 6/30/2013 VIO Concept LTD. 7
  8. 8. Improved SC-FDMA system 6/30/2013 VIO Concept LTD. 8
  9. 9. 6/30/2013 VIO Concept LTD. 9
  10. 10. 6/30/2013 VIO Concept LTD. 10
  11. 11. ATSC 3.0 PHYSICAL LAYER based on SC-FDMA modulation 6/30/2013 VIO Concept LTD. 11
  12. 12. Features • Back computable to ATSC A53 /A153 standards. • Multi-carrier modified SC-FDMA modulation with cyclic prefix and VSB mode of operation. • Uses A/53 data fields and data segments synchronization. • Each data field of A/53 data frame may carry A/53 8VSB signal or ATSC-3.0 SC- FDMA signal. • ATSC-3.0 multi-carrier SC-FDMA signal is modulated by 2VSB, 4VSB, 8VSB, 16VSB, 32VSB and has the same immunity to multipath distortion as corresponding OFDM. • Modes of operation: 1K, 2K, 4K, 8K subcarriers. • Inner FEC : LDPC • Outer FEC : BCH. • Low PARP ( <7 dB) • Low level of out-of-band Distortion : (<60 dB) 6/30/2013 VIO Concept LTD. 12
  13. 13. SC-FMT based ATSC-3.0 is backwards compatible with ATSC A/53 standard. • The ATSC-3.0 standard shall be global. The most difficult problem for development of the global standard is backwards compatibility with existing DTT standards : ATSC, DVB-T, ISDB-T, DTMB. The most important for ATSC-3.0 is the backwards compatibility with ATSC standard, that uses very special 8-VSB modulation. • Version of SC-FDMA system that is backwards compatibility with 8-VSB is shown in next slides. • The SC-FDMA output signal has the same spectrum as 8-VSB signal and the same field and segment synchronization signals as A/53 standard. • The ATSC -3.0 transmitter generates data frames these can include or normal A/53 data fields with 8VSB modulation, or ATSC-3.0 data fields with SC-FDMA modulation. • The existing A/53 receiver can decode only A/53 data fields remove pilots from received signal and to sense pilots as additional noise. This noise has power equal ~ 0.1% of the power of the received signal and not affect the receiver performance. 6/30/2013 VIO Concept LTD. 13
  14. 14. 6/30/2013 VIO Concept LTD. 14 SC-WFMT with VSB modulation
  15. 15. SC-FDMA system with VSB modulation 6/30/2013 VIO Concept LTD. 15
  16. 16. Segment Synch Insertion 6/30/2013 VIO Concept LTD. 16
  17. 17. Structure of ATSC-3.0 Superframe 6/30/2013 VIO Concept LTD. 17
  18. 18. Structure of A/53, ATSC-3.0 and mixed Data Frames 6/30/2013 VIO Concept LTD. 18
  19. 19. Structure of SC-FDMA Symbol 6/30/2013 VIO Concept LTD. 19
  20. 20. Structure of DATA Frame 6/30/2013 VIO Concept LTD. 20
  21. 21. A/53 and ATSC-3.0 Field Synch. 6/30/2013 VIO Concept LTD. 21
  22. 22. Systems performance comparison 6/30/2013 VIO Concept LTD. 22 STANDARD ATSC A/53 DVB-T2 ATSC-3.0 (Single side band) Country of origin USA EUROPE USA Channel Spacing (MHz) 6 1.7,5,6,7,8,10 6 Carrier (Sub-carrier ) Modulation 8VSB QPSK, 16QAM, 64QAM, 256QAM 2VSB, 4VSB, 8VSB, 16VSB, 32VSB, TYPE Single carrier Multi-carrier OFDM Multi-carrier SC-FDMA Single side band Number of Sub-carriers 1 1K, 2K, 4K, 8K, 16K, 32K 1K, 2K, 4K, 8K GUARD Time Relative to symbol length - 1/4,19/128,1/8, 19/256, 1/16, 1/32, 1/128 1/5.6 Data Frame length (ms) 48,38 Not fixed 48,38
  23. 23. 6/30/2013 VIO Concept LTD. 23 Net Bit Rate (Mbps) 19,39 40,2 (typical) 38.4 (typical) Spectral Efficiency (bit/Hz) 3.23 5.025 6.4 Inner FEC Convolutional code 2/3 LDPC LDPC Outer FEC RS ( 207,187) BCH BCH Compatibility With A/53 - No Yes Interleaving Depth ( msec ) 4 80 4 ~ 500 Unique features Low C/N Rotated Const. SC-FDMA, Low C/N MISO No Yes Yes Multi-pipes No Yes Yes PARP (dB) 7.5 11 6.5 Out-band Distortion (dB) -40 -50 -60 STANDARD ATSC A/53 DVB-T2 ATSC-3.0
  24. 24. ATSC -3.0 TRANSMITTER 6/30/2013 VIO Concept LTD. 24
  25. 25. MATLAB SIMULATIONS of the improved SC-FDMA modulation 6/30/2013 VIO Concept LTD. 25
  26. 26. 0 5 10 15 -6 -5 -4 -3 -2 -1 0 PAPR in dB CCDF CCDF of TX signal CCDF in baseband CCDF in passband Spectrum and CCDF of PARP for SC-FDMA signal (Wavelet filter 1) 6/30/2013 VIO Concept LTD. 26 PAPR= 7.5 dB PAPR=5.5 dB 0.5 0.52 0.54 0.56 0.58 0.6 0.62 0.64 0.66 0.68 -100 -90 -80 -70 -60 -50 -40 -30 Normalized Frequency (rad/sample) Power/frequency(dB/rad/sample) Spectrum of TXIF signal after IF filter 65 dB
  27. 27. Spectrum and CCDF of PARP for SC-FDMA signal (Wavelet filter 2) 6/30/2013 VIO Concept LTD. 27 0 5 10 15 -6 -5 -4 -3 -2 -1 0 PAPR in dB CCDF CCDF of TX signal CCDF in baseband CCDF in passband PAPR=6 dB PAPR=3.5 dB 0.54 0.56 0.58 0.6 0.62 0.64 0.66 0.68 -100 -90 -80 -70 -60 -50 -40 -30 Normalized Frequency (rad/sample) Power/frequency(dB/rad/sample) Spectrum of TX IF signal after IF filter
  28. 28. Spectrum and CCDF of PARP for SC-FDMA signal (Wavelet filter 3) 6/30/2013 VIO Concept LTD. 28 0 5 10 15 -6 -5 -4 -3 -2 -1 0 PAPR in dB CCDF CCDF of TX signal CCDF in baseband CCDF in passband PAPR=5.3 dB PAPR=2.5 dB 0.55 0.6 0.65 0.7 0.75 -90 -80 -70 -60 -50 -40 -30 Normalized Frequency (rad/sample) Power/frequency(dB/rad/sample) Spectrum of TXIF signal after IF filter
  29. 29. Output signal of SC-FDMA transmitter 6/30/2013 VIO Concept LTD. 29 0 2 4 6 8 10 12 14 x 10 5 -0.1 -0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1 Tx IF signal
  30. 30. 256QAM constellation diagram -0.6 -0.4 -0.2 0 0.2 0.4 0.6 -0.6 -0.4 -0.2 0 0.2 0.4 0.6Quadrature In-Phase Scatter plot 6/30/2013 VIO Concept LTD. 30
  31. 31. Constellation diagram of received SC-FDMA signal after equalizer. 6/30/2013 VIO Concept LTD. 31
  32. 32. 4096 QAM constellation diagram -60 -40 -20 0 20 40 60 -60 -40 -20 0 20 40 60 Quadrature In-Phase Scatter plot 6/30/2013 VIO Concept LTD. 32
  33. 33. Frame correlator output 6/30/2013 VIO Concept LTD. 33 2000 4000 6000 8000 10000 12000 -10 -5 0 5 10 15 frame correlator output DATA SYMBOL Cyclic Prefix
  34. 34. THANK YOU Contact : Roman Vitenberg Email: r.m.vitenberg@gmail.com Tel:+972547800501 6/30/2013 VIO Concept LTD. 34

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