Application of ping-pong optimized pulse shaping (POPS) to the offline optimization of the 5G radio interface. Waveform optimization for rectangular as well as hexagonal/quincunx time-frequency lattices. Waveform optimization for different waveform durations at the transmit and receive sides. Discussion on the concept of optimized codebooks of pairs of waveforms, to pave the way for the introduction of Adaptive Waveform Communications (AWC) in 5G.

1. 1
Offline Ping-Pong Optimized Pulse Shaping for
Future 5G Systems: POPS-FBMC
Mohamed Siala
MEDIATRON Laboratory
Higher School of Communication of Tunis (SUP’COM)
Carthage University - Tunisia
Boğaziçi Üniversitesi
Beşiktaş/İstanbul - Türkiye
May 11, 2016

2. Outline
 Motivation of Research Activities on Pulse Shaping for 5G
OFDM/OFDMA
 5G Challenges and Requirements
 POPS-OFDM to Systematically Respond to 5G Radio Interface
Challenges
 Conclusion and Perspectives for Future Research Work on 5G
2

3. Motivation of Research Activities on Pulse
Shaping for 5G OFDM/OFDMA
3

4. 5G Challenges and Requirements 1/2
4

5. 5G Challenges and Requirements 2/2
5

6. 4G (LTE-A) Pitfalls
 LTE is tailored to maximize performance by enforcing strict
synchronism and perfect orthogonality 
 Machine-type communication (MTC) requires bulky procedures to
ensure strict synchronism
 Collaborative schemes (e.g. CoMP) use tremendous efforts to
collect gains under strict synchronism and orthogonality
 Digital Agenda/Carrier aggregation forces systems to deal with
fragmented spectrum
6

7. Need for Non-Orthogonal Waveforms
 Non-orthogonal waveforms on the physical layer will enable:
 Asynchronous MTC traffic with drastically reduced signalling and
increased life time
 The provision of asynchronous coordinated multi-point (CoMP) /
Heterogeneous Networking (HetNet)
 Implementation of asynchronous carrier aggregation concepts with
well frequency localization
 A (filtered) multicarrier approach will enable:
 The mix of synchronous/asynchronous and orthogonal/non-
orthogonal traffic types
 The aggregation of non-contiguous spectrum thanks to low out-of-
band emissions of the non-orthogonal waveforms
7

8. Workload of Current Mobiles
8
Outer receiver consists of channel decoder and de-interleaver

9. Projects on 5G
 From 2007 to 2013, the European Union set aside €700 million of
funding (FP7) for research on future networks, half of which was
reserved for the development of 4G and beyond-4G technologies.
 METIS, 5GNOW, iJOIN, TROPIC, Mobile Cloud Networking,
COMBO, MOTO and PHYLAWS are some of the latest EU research
projects that address the architecture and functionality needs of 5G
networks, representing some €50 million EU investment.
 European Union’s FP7 project, PHYDYAS (Duration: 30 months,
Start: January 2008, End: October 2010, Total Cost: 4 093 483€),
investigated Filter Bank Multi-Carrier (FBMC) and corresponding
transceiver functionalities.
9

10. 5GNOW Candidate Waveforms
 European Union’s FP7 projects, 5GNOW (5th Generation Non-
Orthogonal Waveforms for Asynchronous Signaling), (Start:
September 2012, End: February 2015, Total Cost: 3 526 991 €),
investigated 4 candidate waveforms:
 Generalized Frequency Division Multiplexing (GFDM)
 Universal Filtered Multicarrier (UFMC)
 Filter Bank Multi-Carrier (FBMC)
 Bi-orthogonal Frequency Division Multiplexing (BFDM)
10

11. GFDM: Generalized Frequency Division
Multiplexing
11

12. UFMC: Universal Filtered MultiCarrier
12
Spectral behavior within a single sub-band
Single PRB compared to OFDM

13. 5G Challenges and Requirements
13

14. Requirements for 5G: Coordinated MultiPoint
(CoMP)
 Joint Processing (JP):
 Coordination between multiple BSs
 MSs are simultaneously transmitting or receiving to or from
multiple BSs
 Coordinated Scheduling/Coordinated Beamforming (CS/CB):
 Coordination between multiple BSs
 MSs are transmitting or receiving to or from a single transmission
or reception BS
14

15. Requirements for 5G: Coordinated MultiPoint
(CoMP) – Overlapping in Time
15
time
At the BSs
MS2MS1
time
TDOA  Overlapping in time
 Artificial delay spread
 Inter-Symbol Interference
At MS2
time
At MS1
TDOA: Time Difference of Arrival
Applicable even for fully
time synchronous BSs

16. Requirements for 5G: Coordinated MultiPoint
(CoMP) – Overlapping in Frequency
16
MS
frequency
Carrier Frequency Offset 
Overlapping in frequency  Artificial Doppler spread
 Inter-Carrier Interference (ICI)
At MS
From BS1
frequency
frequency
From BS2
From BS3
Applicable only for non fully
frequency Synchronous BSs

17. Requirements for 4G, 5G and DVB-T: MBMS
and SFN 1/2
17
Overlapping replicas  Artificial delay spread  Interference
time
At the BSs/DVB-T TV Station
time
At the TV Set
(SFN)
At the MS
(MBMS)
SFN: Single Frequency
Network
MBMS: Multimedia Broadcast
Multicast Service

18. Requirements for 4G, 5G and DVB-T: MBMS
and SFN 2/2
18
MBMS: Replicas of the same modulated
signal arriving at different delays at the MS
Delay spread
Aggregate “artificial » delay spread

19. Requirements for 5G: Sporadic Traffic and Fast
Dormancy 1/5
 2G, 3G and 4G systems continuously transmit reference signals and
broadcast system information that is used by terminals as they move
across cells
  The more signaling the cellular standard requires, the more complex
and power-hungry will be the devices
 With denser deployment and more network nodes (MTC), such
“always-on” transmissions are not attractive from an interference and
energy consumption perspective
  Maximizing the devices’ sleep opportunities, through sporadic
access, minimizes energy consumption, leading to long battery life
19

20. Requirements for 5G: Sporadic Traffic and Fast
Dormancy 2/5
 Sporadic access poses a significant challenge to mobile access
networks due to fast dormancy:
 Fast dormancy is used to save battery power: The mobile breaks
ties to the network as soon as a data piece is delivered
 When the mobile has to deliver more pieces of data it will always
go through the complete synchronization procedure again
 This can happen several hundred times a day, resulting in
significant control signaling growth and network congestion threat
20

21. Requirements for 5G: Sporadic Traffic and Fast
Dormancy 3/5
21Nokia Siemens Networks, Understanding Smartphone Behavior in the Network,
White Paper, 2011, [Available: http://www.nokiasiemensnetworks.com/sites/default/files
Comparisons of Data and Signaling Traffic

22. Requirements for 5G: Sporadic Traffic and Fast
Dormancy 4/5
  It is desirable to achieve “zero-overhead” communications by
providing channel access with minimal signaling
  Get rid of closed-loop timing control (which costs energy and
signaling overhead, being undesirable for MTC) and use open loop
timing control mechanisms: The device uses the downlink pilot signals
by the BS for a rough synchronization (RSSI: Received Signal
Strength Indication)
22

23. Requirements for 5G: Sporadic Traffic and Fast
Dormancy 5/5
23
Overhead Payload (Useful information)
High data rate service with “always-on” transmission: Overhead << Payload
Time
Overhead Payload (Useful information)
Time
Loss of synchronization
Delayed
transmission
Sporadic access with fast dormancy and no synchronization procedure
Payload (Useful information)
Time
Loss of synchronization
Sporadic access with fast dormancy using a complete synchronization procedure:
Overhead >> Payload

24. Requirements for 5G: Sporadic Traffic and Fast
Dormancy – Relaxed Frequency Synchronization
24
MS2
Reduced synchronization overhead 
Relaxed frequency synchronization 
Carrier Frequency Offset 
Overlapping in frequency 
Inter-user interference in frequency
From MS1
frequency
MS1
MS3
frequency
From MS2
frequency
From MS3
At BS
frequency
Inter-user interference
Unaligned carrier frequencies

25. Requirements for 5G: Sporadic Traffic and Fast
Dormancy – Relaxed Time Synchronization
25
MS2
Reduced synchronization overhead
 Relaxed time synchronization
 Overlapping in time
 Inter-user interference in time
MS1
From MS1
time
time
From MS2
At BS
time
Inter-user interference

26. Requirements for 5G: Asynchronous Signaling in
the Uplink – RACH 1/3
26
MS2MS1
RACH random access
MS2 experiences a higher round-trip delay than MS1

27. Requirements for 5G: Asynchronous Signaling in
the Uplink – RACH 2/3
27
time
No synchronization overhead  Strong overlapping in time
 Inter-user interference in time
To/from BS
time
To/from MS1
To/from MS2
Inter-Burst interference
time
Synchronization
channel
RACH burst
from MS2
RACH burst
from MS1
Propagation
delay to MS1
Propagation
delay to MS2

28. Requirements for 5G: Asynchronous Signaling in
the Uplink – RACH 3/3
28
Use of open loop timing control: The device uses the RSSI for a rough
synchronization  Shadowing disturbance  Partially alleviated
asynchronism
RSSI: Received Signal Strength Indication
Ideal pathloss
Path loss
+ shadowing
Ideal arrival at the BS
(No overlapping)
Actual arrival at the BS
(Overlapping in time)
Time

29. Requirements for 5G: Spectrum Agility and
Carrier Aggregation 1/2
 TV White Spaces (TVWS) exploration can represent a new niche
markets if it overcomes, with spectrum agility, the rigorous
implementation requirements of low out-of-band (OOB) radiations for
protection of legacy systems
 The LTE-A waveform imposes generous guard bands to satisfy
spectral mask requirements which either severely deteriorate spectral
efficiency or even prevent band usage
 5G will address carrier aggregation by implementing non-orthogonal
waveforms, with low OOB emissions, in order not to interfere with
other legacy systems and conform to tight spectral masks
29

30. Requirements for 5G: Spectrum Agility and
Carrier Aggregation 2/2
30
OFDM vs. ESM: Loss of efficiency of traditional OFDM to fit in an ESM
(Emission Spectrum Mask) due to its non-negligible side lobes
55 dB protection

31. Requirements for 5G: Low Latency 1/2
 4G offers latencies of multiple 10 ms between terminal and BS that
originate from resource scheduling, frame processing, retransmission
procedures, and so on.
 The access latency offered by LTE is not sufficient for latency-critical
applications, such as tactile internet (motivated by the tactile sense of
the human body, which can distinguish latencies on the order of 1 ms
accuracy), traffic safety and infrastructure protection.
 To ensure support for such mission-critical MTC applications, next-
generation wireless access should allow for latencies on the order of 1
ms or less.
31

32. Requirements for 5G: Low Latency 2/2
 A 1 ms round-trip time for a typical tactile interaction requires a time
budget of maximum 100 µs on the physical layer
  Far shorter than LTE-A allows, missing the target by nearly two
orders of magnitude
  Clear motivation for an innovative and disruptive redesign of
the PHY layer
 Lower latency over the radio link can be achieved by reducing
transmission-time intervals and widening the bandwidth of radio
resource blocks in which a specific amount of data is transmitted
32

33. Requirements for 5G: Lower Latency vs Doppler
Spread-Delay Spread Balancing 1/2
33
Time
F
T
Frequency
Doppler shift
Time delayDB
mT
Reduced global ICI+ISI
 Good balancing between T and F
 Increased Latency
ICI
ICI
ISIISI
Processing
Time at the Rx2
mT
min
Contribution of the PHY to the latency

34. Requirements for 5G: Lower Latency vs Doppler
Spread-Delay Spread Balancing 2/2
34
Time
F
T
Frequency
Doppler shift
Time
delay
DB
mT
Decreased Latency
 Bad balancing between
T and F
 Increased global
ICI+ISI
ISIISI
Processing
Time at the Rx
2
mTmin
Contribution of the PHY to the latency 
ICI
ICI

35. POPS-OFDM to Systematically Respond to 5G
Radio Interface Challenges
35

36. POPS-OFDM Categories
36
POPS-OFDM
Continuous DiscreteTime
Optimum
exploration space
2
( ) 2
( )
Practical
exploration space
1
0Vect({ ( )} )N
k kt 

1
0Vect({ ( )} )N
k kt 

0{ ( )}k kt 

0{ ( )}k kt 

: Hermite functions
: Prolate Spheroidal Wave Functions (PSWF)
To be explored next
2
( )I 

37. 33φ32φ31φ30φ
23φ22φ21φ20φ
13φ12φ11φ10φ
OFDM Time-Frequency Lattice: Transmitter
Side
Time
Frequency
Signal
00 φ φ 01φ 02φ 03φ
Time Shift by TTime Shift by 2TTime Shift by 3T
Frequency
Shift by F
Frequency
Shift by 2F
Frequency
Shift by 3F
Symbol Period T
=
Symbol Spacing
Symbol Bandwidth F = Subcarrier Spacing
: Transmitter Prototype Waveformφ
mnφ
Subcarrier Index Symbol Index
Frequency shift of  by mF Time shift of  by nT
37

38. 30 30a φ
20 20a φ
10 10a φ
00 00a φ
1
0 0
0
Q
m m
m
a


 φ
OFDM Transmitted Signal
Time
Frequency
Signal
21 21a φ
11 11a φ
01 01a φ
31 31a φ
1
1 1
0
Q
m m
m
a


 φ
1
0
: Sampled Version of the Transmitted OFDM Signal
Q
mn mn
n m
a


 e φ
1
2 2
0
Q
m m
m
a


 φ
32 32a φ
22 22a φ
12 12a φ
02 02a φ
1
3 3
0
Q
m m
m
a


 φ
33 33a φ
23 23a φ
13 13a φ
03 03a φ
SubcarriersQ
38

39. Propagation Channel Characteristics: Delay and
Doppler Spreads
Mobile speed

( , )S p 
p
dB : Doppler spread
Doppler spread spectrum
: Discrete time delay
: Doppler frequency shift
( , )S p  : Channel scattering function
: Discrete time delay spreadmT 39

40. 30 30a φ
20 20a φ
10 10a φ
00 00a φ
1
0 0
0
Q
m m
m
a


 φ
OFDM Received Signal
Time
Frequency
Signal
1
0
: Sampled Version of the Received OFDM Signal
Q
mn mn
n m
a


 r φ n
21 21a φ
11 11a φ
01 01a φ
31 31a φ
1
1 1
0
Q
m m
m
a


 φ
: Additive White Gaussian Noisen
: Channel distorted version ofmn mnφ φ
40
ISIICI

41. Decision variables
: Receiver Prototype Waveform (Vector)ψ
klψ
Subcarrier Index Symbol Index
Frequency shift of  by kF Time shift of  by lT
H
kl kl  ψ r : Decision variable on kla
( , ) ( , ) Noise TermUseful Term
Interference Term
H H H
kl kl kl kl mn kl mn kl
m n k l
a a

   ψ φ ψ φ ψ n
41

42. Signal-to-Interference and Noise Ratio (SINR)
S
I N
P
SINR
P P


: Average power of the Useful Term
: Average power of the Interference Term
: Average power of the Noise Term
S
I
N
P
P
P
( , )
( , )
1
H
S p
H
S p
SINR
SNR



 
 
 
φ
φ
ψ KS ψ
ψ KI I ψ
: Ratio of two definite positive quadratic
forms on  for a given 
( , )
( , )
1
H
S p
H
S p
SINR
SNR


 
 

 
 
 
ψ
ψ
φ KS φ
φ KI I φ
: Ratio of two definite positive quadratic
forms on  for a given 
0
: Signal to Noise Ratio
E
SNR
N

42

43. Offline Ping-pong Optimization Philosophy
1/2
Transmitter Side Receiver Side(0)
φ
(0)
(0)
( , )
( , )
Maximize
1
H
S p
H
S p
SINR
SNR



 
 
 
φ
φ
ψ KS ψ
ψ KI I ψ (0)
ψ
(0)
(0)
( , )
( , )
Maximize
1
H
S p
H
S p
SINR
SNR


 
 

 
 
 
ψ
ψ
φ KS φ
φ KI I φ
(1)
φ
(1)
(1)
( , )
( , )
Maximize
1
H
S p
H
S p
SINR
SNR



 
 
 
φ
φ
ψ KS ψ
ψ KI I ψ (1)
ψ
(1)
(1)
( , )
( , )
Maximize
1
H
S p
H
S p
SINR
SNR


 
 

 
 
 
ψ
ψ
φ KS φ
φ KI I φ
(2)
φ 43

44. Offline Ping-pong Optimization Philosophy
2/2
φ
ψ
(0)
φ
(0)
ψ
(1)
φ
(1)
ψ
(2)
φ
44SINR
Equal-SINR curves
(Contour plot of SINR)
SINR maximum

45. First Optimization Technique
SINR


0
ψ
( , ) ( , )
1
S p S p
SINR
 φ φ
KI ψ KS ψ
Generalized Eigenvalue Problem
Find the eigenvector with the smallest eigenvalue
SINR


0
φ
( , ) ( , )
1
S p S p
SINR
    ψ ψ
KI φ KS φ
45

46. Second Optimization Technique
( , )
( , )
H
S p
H
S p
SINR



φ
φ
ψ KS ψ
ψ KIN ψ
( , )
H
S p  φ
KIN UΛU
: Unitary Matrix
: Diagonal Positive Matrix
U
Λ
( , )
H H H H
S p   φ
ψ KIN ψ ψ UΛU ψ u u 1/2 H
u Λ U ψ
H
H
SINR 
u Φu
u u
1/2 1/2
( , )
H
S p 
 
 φ
Φ Λ U KS UΛ
maxFind the eigenvector of with maximum eigenvalueu Φ
1/2
max
1/2
max
opt



UΛ u
ψ
UΛ u
46

47. Signal and Interference Kernel Computation
1/3
1
( , )
0
( )k
K
H
S p nN k p
n k
 



  
   
  
 φ
K Σ Σ φφ Ω
0 ( ( )) if ( )mod 0
0 else
D s
pq
QJ B T p q p q Q   
  

1
0 ( , )
0
( )k
K
H
S p k p
k
 


 
  
 
φ
K Σ φφ Π
0 ( ( ))pq D sJ B T p q  
( , ) 0 ( , )S p S p φ φ
KS K ( , ) ( , ) 0 ( , )S p S p S p   φ φ φ
KI K K
Π Q Ω
Dependence on channel Doppler (Computed once)
DN Q
47

48. Signal and Interference Kernel Computation
2/3
φ H
φφ  
1
0
( )k
K
H
k p
k



 Σ φφ
Duration: DT
 DN samples
48
Matrix shifts according to
the multipath power profile

49. Signal and Interference Kernel Computation
3/3
Matrix shifts according to
the normalized symbol duration N
49
1
0
( )k
K
H
nN k p
n k



 
 
 
 Σ Σ φφ

50. Numerical Results: Impact of Initialization and
Existence of Local Maxima
50
Local maxima
Conjecture to
be the global
maximum

51. Numerical Results: Evolution of Transmit and
Receive Pulse Shapes Through the Iterations
51
Iterations: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,…,20,…,30,…,100
φ ψ
Initialization: Gaussian pulse

52. Numerical Results: Doppler Spread-Delay Spread
Balancing
52
Best balancing

53. Numerical Results: Optimized Waveforms
53

54. Numerical Results: Optimized Waveforms
54

55. Numerical Results: Performance and Gain in
SINR – Identical Pulse Shape Durations
55
Gain > 5dB

56. Numerical Results: Uneven Distribution of PHY
Delay/Complexity Between Transmitter and
Receiver 1/2
56
PHY delay = (D+D)/2 = 3T

57. Numerical Results: Uneven Distribution of PHY
Delay/Complexity Between Transmitter and
Receiver 2/2
57
PHY delay = (D+D)/2 = 5T

58. Numerical Results: Spectrum of One Subcarrier
58
~ 60 dB

59. Numerical Results: Spectrum of 64 Subcarriers
59
~ 60 dB

60. Numerical Results: Sensitivity to an Estimation
Error on BdTm
60

61. Numerical Results: Sensitivity to Synchronization
Errors in Frequency
61
Tolerence margin > 10%

62. Numerical Results: Sensitivity to Synchronization
Errors in Time
62
38-sample error tolerence
34-sample error tolerence

63. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 1/9
63
T
F
2F
( , )
( , )
/ 2
0
n m
n m
t T T n
f F m
    
    
   
T/2

64. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 2/9
1
0 ( , )
0
( )k
K
H
S p k p
k
 


 
  
 
φ
K Σ φφ Π
0 ( ( ))pq D sJ B T p q  
Π
Dependence on channel Doppler for the 0th Kernel
DN
64

65. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 3/9
1 1
( , ) /2
0 0
( ) ( )k k
K K
H even H odd
S p nN k p nN N k p
n k n k
  
 
 
 
      
       
      
   φ
K Σ Σ φφ Ω Σ Σ φφ Ω
0 ( ( )) if ( )mod 0
2 2
0 else
even D s
pq
Q Q
J B T p q p q

  
  

Dependence on channel Doppler for the infinite kernel 65
0
0
( ( )) if ( )mod 0
2
( ( )) if ( )mod
2 2
0 else
D s
odd
pq D s
Q
J B T p q p q Q
Q Q
J B T p q p q Q



  


     




66. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 4/9
2
even Q
 Ω
Dependence on channel Doppler for the infinite kernel
/ 2Q
66
2
odd Q
 Ω
/ 2Q
Even carrier contribution mask Odd carrier contribution mask

67. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 5/9
67
1
0
( )k
K
H
nN k p
n k



 
 
 
 Σ Σ φφ
1
/2
0
( )k
K
H
nN N k p
n k




 
 
 
 Σ Σ φφ
Selection on which is
based kernel computation
Even carrier contribution
Odd carrier contribution

68. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 6/9
68

69. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 7/9
69
Rectangular lattice
Hexagonal/quincunx
lattice

70. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 8/9
70

71. Staggered (Hexagonal/Quincunx) Time-
Frequency Lattice 9/9
71

72. Transmit and Receive Waveforms with Unequal
Durations 1/7
72
MSBS
Waveforms for the Downlink
MSBS
Waveforms for the Uplink
t t t t
D D  D D 
φφ ψ ψ
The BS can afford more complexity in terms of filtering than the MS

73. Transmit and Receive Waveforms with Unequal
Durations 2/7
73
x =D N
D N
ψ H
ψ
H
ψψ
Assumption: D D 
Given , we search forψ φ

74. Transmit and Receive Waveforms with Unequal
Durations 3/7
74
D N
D N
Selection on which is
based the kernel for
the computation of φ

75. Transmit and Receive Waveforms with Unequal
Durations 4/7
75
x =
D N
D N
φ H
φ
H
φφ
Assumption: D D 
Given , we search forφ ψ

76. Transmit and Receive Waveforms with Unequal
Durations 5/7
76
D N
D N
Selection on which is
based the kernel for
the computation of ψ

77. Transmit and Receive Waveforms with Unequal
Durations 6/7
77

78. Transmit and Receive Waveforms with Unequal
Durations 7/7
78

79. SINR Kernal Characteristics and Consequences
1/4
79
( , ) ( , )
( , ) ( , )
1 1
H H
S p S p
H H
S p S p
SNR SNR
 
 


 
 

   
    
   
ψφ
ψφ
ψ KS ψ φ KS φ
ψ KI I ψ φ KI I φ
Time reverse of φ
Time reverse of ψ

80. SINR Kernal Characteristics and Consequences
2/4
80
φ ψ φψ
In terms of noise correlation at the receiver
φ ψ φψ
In terms of SINR
Not always equivalent

81. SINR Kernal Characteristics and Consequences
3/4
81
PC
Timeφ
ψ Time
CP-OFDM
Timeφ
ψ Time
ZP-OFDM
ZP
Only in terms of SINR
Time
reversing
CP-OFDM and ZP-OFDM are duals of each other

82. SINR Kernal Characteristics and Consequences
4/4
82
If the optimum couple (, ), maximizing the SINR, is unique, then
ψ φ

83. Adaptive Waveform Communication: A New
Link Adaptation Paradigm 1/5
83
d mB T
SINR [dB]
Best achieved SINR for each BdTm,
using always the optimum pair (, )
1( )d mB T 2( )d mB T
SINR performance for pair (1,  1)
optimized for (BdTm)1
SINR performance for pair (2,  2)
optimized for (BdTm)2

84. Adaptive Waveform Communication: A New
Link Adaptation Paradigm 2/5
84
d mB T
SINR [dB]
Best achieved SINR for each BdTm,
using always the optimum pair (, )
Use of pair (1,  1) Use of pair (2,  2)
Waveform Codebook

85. Adaptive Waveform Communication: A New
Link Adaptation Paradigm 3/5
85
d mB T
SINR [dB] Instantaneous and average losses in SINR
A priori distributions of BdTm
Most seen SINR loss
for the red a priori
Most seen SINR loss
for the blue a priori

86. Adaptive Waveform Communication: A New
Link Adaptation Paradigm 4/5
86
d mB T
SINR [dB]
Codebook optimization:
Notion of multiple codebooks
2 different services  2 different a priori distributions of BdTm
Codebook #1
Codebook #2
A priori distribution
for service #1
A priori distribution
for service #2

87. Adaptive Waveform Communication: A New
Link Adaptation Paradigm 5/5
87
With full characterization of the scattering function
dB
mT
A priori distributions
of (Bd, Tm) corresponding
to different services
(Bd, Tm) values for which
pairs of waveforms
constituting the
codebook are optimized

88. Conclusion and Perspectives for Future Research
Work on 5G
88

89. Conclusion
 We proposed a new and straightforward technique for the
systematic offline optimization of transmit and receive
waveforms for OFDM/FBMC systems
 Increased SINR
 6 orders of magnitude reduction in out-of-band emissions
using rectangular time-frequency lattice
 7 orders of magnitude reduction in out-of-band emissions
using hexagonal time-frequency lattice
 Unequal time durations for transmit and receive
waveforms to adapt to affordable computational resources
 Robustness to synchronization errors 89

90. Ongoing Research Work
 Current extensions to:
 OFDM/OQAM
 Reverse-time channel
 Unequal-duration waveforms
 Hexagonal-lattice OFDM/QAM
 Partial equalization
 Single-carrier (satellite) communications
 OFDMA/QAM
 Multi-pulse OFDM/QAM
 Windowed OFDM
 Faster-than-Nyquist (FTN) signalling
 Unique-Word OFDM
90

91. Perspectives
 Future extensions to:
 Multi-pulse OFDM/OQAM
 Hexagonal-lattice OFDM/OQAM
 Underwater acoustic communications
 Relaxed synchronization (RACH, MTC)
 Carrier aggregation and reduced out-of band emissions
 Low latency communications
 RADAR/SONAR
 5G interface optimization (Standardization inside 3GPP RAN-L1)
91

92. 92
Thank You for Your Attention!
Mohamed Siala
MEDIATRON Laboratory
Higher School of Communication of Tunis (SUP’COM)
Carthage University - Tunisia
Boğaziçi Üniversitesi
Beşiktaş/İstanbul - Türkiye
May 11, 2016

93. References 1/4
 M. Siala, T. Kurt, and A. Yongaçoglu, “Orthonormalization for Multi-Carrier Transmission,”
Canadian Workshop on Information Theory 2005 (CWIT’05), Montreal, Quebec, Canada, June 2005.
 T. Kurt, M. Siala, and A. Yongaçoglu, “Multi-Carrier Signal Shaping Employing Hermite
Functions,” European Signal Processing Conference 2005 (EUSIPCO’05), Antalya, Turkey,
September 2005.
 N. Debbabi, M. Siala, and H. Boujemâa, “Optimization of the OFDM Prototype Waveform for
Highly Time and Frequency Dispersive Channels Through a Maximization of the SIR,” 12th
IEEE International Conference on Electronics, Circuits and Systems 2005 (ICECS’05), Gammarth,
Tunisia, December 2005.
 A. Ben Salem, M. Siala, and H. Boujemâa, “Performance Comparison of OFDM and
OFDM/OQAM Systems Operating in Highly Time and Frequency Dispersive Radio-Mobile
Channels,” 12th IEEE International Conference on Electronics, Circuits and Systems 2005
(ICECS’05), Gammarth, Tunisia, December 2005.
 M. Siala, T. Kurt, and A. Yongaçoglu, “A Unified Framework for the Construction of
OFDM/OQAM Systems,” 12th IEEE International Conference on Electronics, Circuits and Systems
2005 (ICECS’05), Gammarth, Tunisia, December 2005.
93

94. References 2/4
 A. Ben Salem, M. Siala, and H. Boujemâa, “OFDM systems with hexagonal time-frequency
lattices and well time frequency localized prototype functions,” Third International Symposium
on Image/Video Communications over fixed and mobile networks 2006 (ISIVC’06), Hammamet,
Tunisia, September 2006.
 M. Siala, “Novel OFDM/OQAM system with hexagonal time-frequency lattice,” Third
International Symposium on Image/Video Communications over fixed and mobile networks
(ISIVC’06), Hammamet, Tunisia, September 2006.
 I. Trigui, M. Siala, and H. Boujemâa, “Optimized pulse shaping for OFDM multi-user
communications over doubly dispersive channels,” 9th International Symposium on Signal
Processing and its Applications (ISSPA’07), Sharjah, United Arab Emirates, February 2007.
 M. Siala and A. Yongaçoglu, “Prototype waveform optimization for an OFDM/OQAM system
with hexagonal time-frequency lattice structure,” 9th International Symposium on Signal
Processing and its Applications (ISSPA’07), Sharjah, United Arab Emirates, February 2007.
 I. Trigui, M. Siala, S. Affes and A. Stephenne, “SIR Optimized Hermite-Based Pulses for BFDM
Systems in Doubly Dispersive Channels,” International Symposium on Signals, Systems and
Electronics (ISSSE’07), Montreal, Quebec, Canada, July 2007.
94

95. References 3/4
 R. Ayadi, I. Kammoun, and M. Siala, “Optimization of the pulse shape of OFDM systems Using
the Arrow-Hurwicz Algorithm,” 4th International Symposium on Wireless Communication Systems
(ISWCS’07), Trondheim, Norway, October 2007.
 R. Ayadi, M. Siala, and I. Kammoun, “Transmit/receive pulse-shaping design in BFDM systems
over time-frequency dispersive AWGN channel,” IEEE International Conference on Signal
Processing and Communications (ICSPC’07), Dubai, United Arab Emirates, November 2007.
 I. Trigui, M. Siala, S. Affes, A. Stephenne, and H. Boujemaa, “Optimum Pulse Shaping for
OFDM/BFDM Systems Operating in Time Varying Multi-Path Channels,” IEEE Global
Telecommunications Conference (GLOBECOM’07), Washington DC, USA, November 2007.
 M. Bellili, M. Siala, and L. Ben Hadj Slama, “Pulse design for maximizing SIR in partially
equalized OFDM/BFDM systems,” IEEE 19th International Symposium on Personal, Indoor and
Mobile Radio Communications (PIMRC’08), Cannes, France, September 2008.
 M. Bellili, L. Ben Hadj Slama, and M. Siala, “Multi-pulse/single-pulse design for maximizing SIR
in partially equalized OFDM systems over highly dispersive channels,” 16th IEEE International
Conference on Electronics, Circuits, and Systems, 2009 (ICECS 2009), Hammamet, Tunisia,
December 2009.
95

96. References 4/4
 R. Ayadi, I. Kammoun, and M. Siala, “Optimal OFDM Pulse Design, Analysis and
Implementation Over Doubly Dispersive Channel,” 21st European Signal Processing Conference
(EUSIPCO 2013), Marrakech, Morocco, September 9-13, 2013.
 M. Siala, F. Abdelkefi and Z. Hraiech, “Novel Algorithms for Optimal Waveforms Design in
Multicarrier Systems,” IEEE Wireless Communications and Networking Conference
(WCNC’2014), Istanbul, Turkey, April 2014.
 Z. Hraiech, M. Siala, and F. Abdelkefi, “Numerical Characterization for Optimal Designed
Waveform to Multicarrier Systems in 5G,” 22nd European Signal Processing Conference 2014
(EUSIPCO’2014), Lisbon, Portugal, 1-5 September 2014.
 Z. Hraiech, F. Abdelkefi, and M. Siala, “POPS-OFDM: Ping-pong Optimized Pulse Shaping-
OFDM for 5G systems,” IEEE International Conference on Communications (ICC’15), London,
UK, June 2015.
 Z. Hraiech, F. Abdelkefi, and M. Siala, “POPS-OFDM: Ping-pong Optimized Pulse Shaping-
OFDM for 5G systems,” IEEE Vehicular Technology Conference – Spring 2015 (VTC’S15),
Glasgow, Scotland, May 2015.
 Z. Hraiech, F. Abdelkefi, and M. Siala, “POPS-OFDM with different Tx/Rx pulse shape
durations for 5G systems,” Fifth International Conference on Communications and Networking
(COMNET’2015), Hammamet, Tunisia, November 2015. 96