Se ha denunciado esta presentación.
Utilizamos tu perfil de LinkedIn y tus datos de actividad para personalizar los anuncios y mostrarte publicidad más relevante. Puedes cambiar tus preferencias de publicidad en cualquier momento.

System Level 5G Evaluation of GFDM Waveforms in an LTE-A Platform

Presentation given at the ISWCS conference in Poland in September 2016.

  • Inicia sesión para ver los comentarios

System Level 5G Evaluation of GFDM Waveforms in an LTE-A Platform

  1. 1. Communication Systems & Networks © CSN Group 2016 System Level 5G Evaluation of GFDM Waveforms in an LTE-A Platform Ghaith Al-Juboori, Angela Doufexi, Andrew Nix
  2. 2. Communication Systems & Networks © CSN Group 2016  Introduction.  Objective of the Paper.  Review of the OFDM Scheme  Generalised Frequency Division Multiplexing.  System Level Study.  Results Discussion .  Conclusion. Presentation Outline 2
  3. 3. Communication Systems & Networks © CSN Group 2016 Introduction: 3 The 5G has different requirements due to the variety of its applications like:  Machine Type Communication (MTC).  Internet of Things (IoT).  High data rate mobile Communications. To achieve these requirements different techniques will be deployed such as:  Massive MIMO.  Millimeter waves bands.  New physical layer’s waveform.
  4. 4. Communication Systems & Networks © CSN Group 2016 Objective of the Paper The new 5G waveform is required to support smooth transition from the existing 4G solutions. In this paper, the performance of the GFDM waveform (BER, PER, Throughput, Out Of Band radiation) is studied and analysed in LTE-A platform using system level study, using 3D-3GPP ITU channel model, has been performed . Additionally, performance comparison with OFDM has been done. Physical layer waveform is a key factor due to its impact on transceiver complexity and system level performance. Recent research for the 5G’s waveform selection are divided to:  Enhance and alternate OFDM waveform.  Using a new waveform such as: FBMC, UFMC,BFDM,GFDM
  5. 5. Communication Systems & Networks © CSN Group 2016 Review of the OFDM Scheme 5 OFDM has many advantages such as:  Robustness to ISI.  Easy to implement using IFFT/FFT However, it suffers from many disadvantages as follows:  Its strong out-of-band radiation (due to use the rectangular pulse filter).  High Peak to Average Power Ratio (PAPR).  It is very sensitive in terms of carrier frequency offset, which requires sophisticated synchronization mechanisms to guarantee that the orthogonality is not affect.  The Cyclic Prefix (CP) approach constitutes a necessary overhead that can reduce the overall energy and spectral efficiency of the system.
  6. 6. Communication Systems & Networks © CSN Group 2016 Generalised Frequency Division Multiplexing (GFDM)-1- 6 𝑥 𝑛 = 𝑚=0 𝑀−1 𝑘=0 𝐾−1 𝑑 𝑘[𝑚 ⊛ 𝑔 𝑇𝑥 [𝑛 − 𝑚𝐾 𝑒 𝑗2𝜋 𝑘 𝐾 𝑛 Figure (1): Basic Structure of the GFDM Transmitter. +S/P X(n) d0,0 , … , d0,M-1 UP CONVERSION UP SAMPLING FILTERING XX Exp(0) XX Exp(j2π((K-1)/K)n) dK-1,0 ,…, dK-1,M-1 MAPPING BINARY DATA gTx[n] K K
  7. 7. Communication Systems & Networks © CSN Group 2016 7 Generalised Frequency Division Multiplexing (GFDM)-2- 7 Figure(2): CP shortening using tail biting  Tail biting technique reduces the length of CP and keeps it equal to CP-OFDM case  Moreover GFDM spectral efficiency is improved by adding only single CP for the entire block that contain M symbols Figure(3): GFDM(K=4 & M=4) and the equivalent OFDM (K=4 & M=1) blocks. a-GFDM b-OFDM
  8. 8. Communication Systems & Networks © CSN Group 2016 System Level Study: Simulation Parameters -1-: 8 R ` BS-06BS-01 BS-02 BS-03 BS-04 BS-05 BS-Main 2R 3R Sector-1 Sector-2 Sector-3 Sector-1 Sector-2 Sector-3 Fig. (4): Cell layout using 3GPP – 3 sector site. Parameter Value Channel model Extend 3D -3GPP-ITU PDCSH simulation model Bit level Simulator Bandwidth 20 MHz Carrier Frequency 2.6 GHz Environment Urban-Macro Main BS-UEs distance 50 - 1000 m Cell Radius 500 m BS transmit power 43 dBm No. of use per cell 900 BS antenna height 25 m BS down tilde 10 º Minimum user sensitivity -120 dBm Link direction Downlink (from BS to UE) Noise Figure 9 dB Channel Coding Turbo Code MCS modes QPSK1/3, QPSK1/2, QPSK2/3, 16QAM1/2, 16QAM2/3, 16QAM4/5, 64QAM2/3, 64QAM3/4, 64QAM 4/5 TABLE I : SYSTEM LEVEL PARAMETERS
  9. 9. Communication Systems & Networks © CSN Group 2016 System Level Study: Simulation Parameters -2-: 9 Parameter Value Sub-frame duration 1ms or 30,720 samples GFDM symbol duration 66.67µs or 2048 samples Sub-symbol duration 4.17µs or 128 samples Sub-carrier spacing 240 kHz Sub-carrier bandwidth 240 kHz Sampling frequency 30.72 MHz Sub-carrier spacing factor (K) 128 No. of active subcarrier (Kon ) 75 No. of Sub-symbols per GFDM symbol (M) 15 No. of GFDM per sub-frame 15 CP length 4.17µs or 128 samples Prototype filter Dirichlet TABLE III :GFDM based LTE-A PARAMETERS. Parameter Value Sub-frame duration 1ms or 30,720 samples Slot duration 0.5 ms Subcarrier spacing 15kHz Sampling Frequency (clock) 30.72MHz Number of subcarriers 2048 Number of active sub-carriers 1200 Resource block 12 subcarriers of one slot Number of OFDM per sub-frame 14 (7 per time slot) CP length-First symbol 160 CP length-Other symbols 144 TABLE II: OFDM based LTE-A PARAMETERS.
  10. 10. Communication Systems & Networks © CSN Group 2016 Results -1-: Performance Analysis of BER. 10 0 5 10 15 20 10 -4 10 -3 10 -2 10 -1 10 0 SNR(dB) BER OFDM-AWGN-hard GFDM-AWGN-hard OFDM-AWGN-soft GFDM-AWGN-soft uncoded-Theoretical Figure. (5): Waveforms performance in AWGN channel. 0 10 20 30 40 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 SNR(dB) BER OFDM-Rayleigh-hard GFDM-Rayleigh-hard OFDM-Rayleigh-soft GFDM-Rayleigh-soft uncoded -Theoretical Figure. (6): Waveforms performance in Rayleigh channel Figure (7): Waveform performance in realistic channel scenario for certain UE 0 5 10 15 20 25 30 35 40 10 -4 10 -3 10 -2 10 -1 10 0 SNR(dB) BER OFDM-QPSK-1/3 GFDM-QPSK-1/3 OFDM-16QAM-1/2 GFDM-16QAM-1/2 OFDM-64QAM-2/3 GFDM-64QAM-2/3
  11. 11. Communication Systems & Networks © CSN Group 2016 Results -2-: System Level Analysis 11 -10 -5 0 5 10 15 20 25 30 35 40 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 SNR(SINR) in dB Probbability(SNR<abscissa) SNR SINR Figure (8): (CDF) for the UEs’ SNR and SINR. 0 20 40 60 80 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Throughput (Mbps) Prob(x<=abscissa) OFDM-SNR OFDM-SINR GFDM-SNR GFDM-SINR Figure. (9):CDF of Throughput using adaptive MCS selection . 0 0.5 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 PER Prob(PER<=abscissa) OFDM-MCS1-QPSK 1/3 OFDM-MCS2-QPSK 1/2 OFDM-MCS3-QPSK 2/3 OFDM-MCS4-16QAM-1/2 OFDM-MCS5-16QAM-2/3 OFDM-MCS6-16QAM-4/5 OFDM-MCS7-64QAM-2/3 OFDM-MCS8-64QAM-3/4 OFDM-MCS9-64QAM-4/5 GFDM-MCS1-QPSK 1/3 GFDM-MCS2-QPSK 1/2 GFDM-MCS3-QPSK 2/3 GFDM-MCS4-16QAM-1/2 GFDM-MCS5-16QAM-2/3 GFDM-MCS6-16QAM-4/5 GFDM-MCS7-64QAM-2/3 GFDM-MCS8-64QAM-3/4 GFDM-MCS9-64QAM-4/5 Figure (10): CDF of the PER with different MCSs in interference-included case.
  12. 12. Communication Systems & Networks © CSN Group 2016 Figure. (11): Power Spectral Density (PSD) for GFDM and OFDM. Results -3-: Out-Of-Band (OOB) Radiation Comparison. -GFDM results in around 6dB reduction in the OOB radiation compared to OFDM. -Different methods can be used to reduce the OOB radiation for GFDM such as:  Guard Symbols (GS) method improves the OOB radiation by approx. 20dB.  Pinching the Block Boundary method improves the OOB radiation by approx.25-45 dB depends on the window type used. 0 5 10 15 20 25 30 35 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 Frequency(MHz) PSD(dB) OFDM GFDM GS-GFDM W-GFDM-Ramp window W-GFDM-RC window
  13. 13. Communication Systems & Networks © CSN Group 2016 Conclusion The performance of the GFDM waveform in LTE-A is evaluated and compared with the OFDM performance in different channel types and also in system level study. The results reveal:  BER, PER and Throughput ,for both waveforms, match closely.  An improvement of 6 dB in the OOB radiation can be obtained in GFDM compared to OFDM. More OOB radiation reduction can be obtained, in the GFDM case, by applying some techniques like GS..  Higher difference are expected, especially in the OOB radiation reduction, when some parameters for LTE-A are adopted appropriately for the GFDM.
  14. 14. Communication Systems & Networks © CSN Group 2016 AnyQuestion? Thank You Email: {Ghaith.Al-juboori, Angela.Doufexi, Andy.nix}@bristol.ac.uk

×