This document evaluates and compares the performance of GFDM and OFDM waveforms in an LTE-A system level study. It finds that GFDM can achieve around 6dB reduction in out-of-band radiation compared to OFDM. BER, PER and throughput are similar between the two waveforms in different channel conditions. GFDM's out-of-band radiation can be reduced further using techniques like guard symbols or windowing. The document concludes that GFDM is a promising candidate for 5G waveforms.

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Communication Systems & Networks
© CSN Group 2016
AnyQuestion?
Thank You
Email: {Ghaith.Al-juboori, Angela.Doufexi, Andy.nix}@bristol.ac.uk