Design and Optimization for 5G Wireless Communications, I by Kim

Design and Optimization for 5G Wireless Communications

Haesik Kim

VTT Oulu, Finland

 

 

 

 

 

 

 

 

 

Wiley Logo

To my wife Hyeeun,

daughter Naul,

son Hanul

and

mother Hyungsuk

Preface

From 1G to 4G cellular networks, the main target of development was system capacity improvement. Thus, the current cellular systems have very efficient system architectures in terms of system capacity. However, it is not an optimal solution in terms of other system parameters (latency, energy efficiency, connection density, etc.). 5G systems have ambitious goals, and 5G applications cover various areas such as eHealth, factory automation, automated vehicles, critical communication, and so on. In recent mobile communications and networks events, leading mobile phone vendors and network equipment vendors have exhibited more than smartphones and networks. Connected and automated vehicles, smart cities, drones, and factory automations were highlighted, and they are highly related to latency, energy efficiency, mobility, and connection density. Thus, 5G systems no longer focus on system capacity only. Many other system parameters should be improved significantly. 5G applications can be classified into (i) enhanced mobile broadband communication (eMBB), (ii) ultra‐reliable and low latency communication (URLLC), and (iii) massive machine type communication (mMTC). Their target system parameters are different in accordance with use cases. The key metrics of eMBB, URLL, and mMTC are system capacity, latency, and connection density, respectively. They also have different system requirements and architectures. In this book, we analyze and design 5G communication and network systems from a different perspective. We introduce mathematical tools and find an optimal, suboptimal or tradeoff point to meet the system requirements.

There is a big gap between theoretical design and practical implementation. Countless papers are published every year to optimize wireless communication systems in academia, but their practical use is very limited in industry. The reasons why they have a big gap can be summarized as simple system models, limited target parameters, and lack of a holistic design. First, optimization algorithms are applied under simple system models. The simple system models sometimes include unrealistic system parameters such as perfect channel state information, limited numbers of users, no interferences, and so on. They allow optimization algorithms to solve the problem nicely, but they are far from practical solutions. Secondly, each optimization algorithm targets only one system parameter (for example, energy efficiency) while other system parameters (for example, system throughput, latency, complexity, and so on.) are not close to an optimal solution, and are sometimes even worse. Thirdly, one optimization algorithm is applied to a small part or component of a communication architecture and it finds an optimal solution. From a holistic point of view, the solution is not optimal. For example, although we design an energy‐efficient multicarrier modulation scheme and achieve significant energy savings, the other parameters might be worse and bring a higher energy consumption to another component. The architecture design is highly related to many other components of communications and networks. Sometimes there is a trade‐off relationship and sometime there is no optimal point. One decision in one design step is highly related to another decision in the next design step. It is very difficult to optimize many metrics such as complexity, system capacity, latency, energy efficiency, connection density, and flexibility. Thus, a wireless communication system designer makes a decision subjectively and empirically. It is a big challenge to reduce the gap between theoretical design and practical implementation.

This book introduces mathematical methods and optimization algorithms for wireless communications and networks and helps audiences find an optimal, suboptimal or tradeoff solution for each communication problem using the optimization algorithms. By this approach, audiences can understand how to obtain a solution under specific conditions and realize the limit of the solution.

This book is not a math book, and we skip the proofs of mathematical formulae and algorithms. This book focuses on design and optimization for 5G communication systems including eMBB, URLLC, and mMTC. The organization of the book is as follows: in Part I, mathematical methods and optimization algorithms for wireless communications are introduced. It will provide audiences with a mathematical background including approximation theory, LS estimation, MMSE estimation, ML and MAP estimation, matrix factorization, linear programming, convex optimization, gradient descent method, supervised and unsupervised learning, reinforcement learning, and so on. In Part II, 5G communication systems are designed and optimized using the mathematical methods and optimization algorithms. For example, the key metric of URLLC is latency. The latency is highly related to many PHY/MAC/network layer parameters such as frame size, transmit time interval, hybrid automatic repeat request (HARQ) processing time, round trip time, discontinuous reception, and so on. We look into them to minimize the latency. In addition, we design some key components using the optimization algorithms. It covers 5G NR, multiple input multiple output (MIMO), 5G waveforms (OFDMA, FBMC, GFDM, and UFMC), low‐density parity‐check (LDPC), short packet transmission theory, latency analysis of 4G and 5G networks, MEC optimizations, robust optimization, power control and management, wireless sensor networks, and so on. The main purpose of this book is to introduce mathematical methods and optimization algorithms and design 5G communication systems (eMBB, URLLC, mMTC) with a different perspective.

I am pleased to acknowledge the support of the VTT Technical Research Centre of Finland and John Wiley & Sons, and also the valuable discussion of my colleagues and experts in EU projects Flex5Gware, 5G‐Enhance, and 5G‐HEART. I am grateful for the support of my family and friends.

Haesik Kim
VTT Oulu, Finland

List of Abbreviations

1G
first generation
2G
second generation
3G
third generation
3GPP
Third Generation Partnership Project
4G
fourth generation
5G
fifth generation
5GC
5G core
ACK
acknowledge
ACLR
adjacent channel leakage ratio
ACM
adaptive coding and modulation
ADSL
asymmetric digital subscriber line
AI
artificial intelligence
AMF
access and mobility management function
AMPS
Advanced Mobile Phone Service
APP
a posteriori probability
AR
augmented reality
ARFCN
Absolute Radio Frequency Channel Number
ARO
adjustable robust optimization
ARQ
automatic repeat request
AS
access stratum
AWGN
additive white Gaussian noise
BBU
baseband unit
BCCH
broadcast control channel
BCH
broadcast channel
BER
bit error rate
BLER
block error ratio
BMSE
Bayesian mean squared error
BP
belief propagation
BPSK
binary phase shift keying
BWP
bandwidth part
CapEx
capital expenditure
CBG
code block group
CCCH
common control channel
CCE
control channel element
CCSDS
Consultative Committee for Space Data Systems
cdf
cumulative distribution function
CDMA
code‐division multiple access
CINR
carrier‐to‐interference plus noise ratio
CN
core network
CORESET
configurable control resource set
CP
convex optimization problems
CP
cyclic prefix
CPU
central processing unit
C‐plane
control‐plane
CQI
channel quality indicator
CQP
convex quadratic programming
C‐RAN
cloud radio access network
CRC
cyclic redundancy check
C‐RNTI
cell radio network temporary identifier
CRSC
circular recursive systematic constituent
CSI
channel state information
CSI‐RS
channel state information reference signal
CSIT
channel state information at transmitter
CSS
chirp spread spectrum
D2D
device‐to‐device
DARPA
Defense Advanced Research Projects Agency
D‐BLAST
Diagonal Bell Laboratories Layered Space–Time
DCCH
dedicated control channel
DCI
downlink control information
DFT
discrete Fourier transform
DL
downlink
DL‐SCH
downlink shared channel
DMC
discrete memoryless channel
DMRS
demodulation reference signal
DNS
domain name service
DRB
data radio bearer
DRX
discontinuous reception
DSN
distributed sensor network
DSSS
direct sequence spreading spectrum
DTCH
dedicated traffic channel
E2E
end‐to‐end
EC‐GSM‐IoT
extended coverage global system for mobile communications IoT
E‐DCH
enhance dedicated channel
EDGE
Enhanced Data rates for GSM Evolution
eGPRS
enhanced general packet radio service
eMBB
enhanced mobile broadband communication
eMTC
enhanced machine‐type communication
eNB
evolved Node B
EPC
enhanced packet core
ETSI
European Telecommunications Standard Institute
EV‐DO
Evolution, Data Only
FA
false alarm
FBMC
filter bank multicarrier
FDD
frequency division duplexing
FDM
frequency division multiplexing
FDMA
frequency division multiple access
FD‐MIMO
full‐dimension MIMO
FER
frame error rate
FFT
fast Fourier transform
FM
frequency modulation
FONC
first‐order necessary condition
GF
Galois Field
GFDM
generalized frequency division multiplexing
GMSK
Gaussian minimum shift keying
gNB
next‐generation NodeB
GPO
generalized precoded OFDMA
GPRS
general packet radio services
GSM
global system for mobile communications
HARQ
hybrid automatic repeat request
HSCSD
high‐speed circuit‐switched data
HSDPA
high speed downlink packet access
HSPA
high‐speed packet access
HSUPA
high‐speed uplink packet access
ICI
inter‐carrier interference
IDFT
inverse discrete Fourier transform
IFFT
inverse fast Fourier transform
IoT
Internet of Things
IPM
interior point method
ISI
inter‐symbol interference
ITU
International Telecommunication Union
ITU‐R
ITU's Radiocommunication Sector
KKT
Karush–Kuhn–Tucker
KPI
key performance indicator
LDC
linear dispersion code
LDPC
low‐density parity‐check
LIDAR
Light Detection and Ranging
LoRa
long range
LP
linear programming
LPWAN
lower power wide area network
LS
least squares
LTE
Long Term Evolution
LU
lower upper
M2M
machine‐to‐machine
MAC
medium access control
MAP
maximum a posteriori
MCG
master cell group
MD
missed detection
MDP
Markov decision problem/process
MEC
multi‐access edge computing
MF
matched filter
MIB
master information block
MIMO
multiple input multiple output
ML
maximum likelihood
MME
mobility management entity
MMS
multimedia messaging services
MMSE
minimum mean‐squared error
mMTC
massive machine type communication
mmWAVE
millimetre wave
MNO
mobile network operators
MRC
maximum ratio combining
MRT
maximum ratio transmission
MSE
mean square error
MVNO
mobile virtual network operators
MVU
minimum variance unbiased
NACK
negative acknowledge
NAS
non‐access stratum
NAT
network address translation
NB‐IoT
narrowband IoT
NB‐PCID
narrowband physical cell identity
NEF
network exposure function
NFV
network functions virtualization
NGMN
Next Generation Mobile Network
NG‐RAN
next generation RAN
NMT
Nordic Mobile Telephone
Node B
base station
NOMA
nonorthogonal multiple access
NP
nondeterministic polynomial
NPBCH
narrowband physical broadcast channel
NPDCCH
narrowband physical downlink control channel
NPDSCH
narrowband physical downlink shared channel
NPRACH
narrowband physical random access channel
NPSS
narrowband primary synchronization signal
NPUSCH
narrowband physical uplink shared channel
NR
new radio
NRS
narrowband reference signal
NSA
non‐standalone
NSSI
network slice subnet instance
NSSS
narrowband secondary synchronization signal
NTT
Nippon Telegraph and Telephone
OFDM
orthogonal frequency division multiplexing
OFDMA
orthogonal frequency division multiple access
OMA
orthogonal multiple access
OOBE
out‐of‐band emission
OpEx
operational expenditure
OQAM
offset quadrature amplitude modulation
OSTBC
orthogonal space–time block code
OTT
over‐the‐top
PAPR
peak‐to‐average power ratio
PBCH
physical broadcast channel
PCCH
paging control channel
PCH
paging channel
PDCCH
physical downlink control channel
PDCP
packet data convergence protocol
pdf
probability density function
PDN‐GW
packet data network gateway
PDSCH
physical downlink shared channel
PDU
protocol data unit
PEP
pairwise error probability
PHY
physical
pmf
probability mass function
PPN
polyphase network
PRACH
physical random access channel
PRB
physical resource block
PSM
power‐saving mode
PSS
primary synchronization signal
PSTN
public switched telephone network
PTRS
phase tracking reference signal
PUCCH
physical uplink control channel
PUSCH
physical uplink shared channel
QAM
quadrature amplitude modulation
QCQP
quadratically constrained quadratic program
QFI
QoS flow ID
QoS
quality of service
QP
quadratic programming
QPSK
quadrature phase shift keying
RACH
random access channel
RAN
radio access network
RB
resource block
REG
resource element group
RF
radio frequency
RL
reinforcement learning
RLC
radio link control
RO
robust optimization
RRC
radio resource control
RRU
remote radio unit
RS
Reed‐Solomon
RTT
round trip time
SA
standalone
SARSA
state‐action‐reward‐state‐action
SC‐CPS
single carrier circularly pulse shaped
SC‐FDM
single carrier frequency division multiplexing
SCG
secondary cell group
SDAP
service data adaption protocol
SDL
supplemental downlink
SDMA
space division multiple access
SDN
software defined networking
SDP
semidefinite programming
SDR
semidefinite relaxation
SDU
service data unit
SE
standard error
SGW
serving gateway
SIC
successive interference cancellation
SINR
signal‐to‐interference‐plus‐noise ratio
SIR
signal‐to‐interference ratio
SMDP
semi‐Markov decision problem
SMF
session management function
SMS
short messaging service
SN
sequence number
SNR
signal‐to‐noise ratio
SOCP
second‐order cone programming
SONC
second‐order necessary condition
SOSC
second‐order sufficient condition
SRS
sounding reference signal
SSB
synchronization signal block
SSE
sum of the squared errors
SSQ
sum of squares
SSS
secondary synchronization signal
STBC
space–time block code
STSK
space–time shift keying
STTC
space–time trellis code
SVD
singular value decomposition
SVM
support vector machine
SUMT
sequential unconstrained minimization technique
TCP
transmission control protocol
TCM
trellis‐coded modulation
TD
temporal difference
TDD
time division duplexing
TDMA
time division multiple access
TM
transmission mode
TN
transport network
TRxP
transmission reception point
TTI
transmission time interval
UE
user equipment
UFMC
universal filtered multicarrier
UHD
ultra‐high definition
UL
uplink
UL‐SCH
uplink shared channel
UMTS
Universal Mobile Telecommunications Service
UPF
user plane function
U‐plane
user‐plane
URLLC
ultra‐reliable and low latency communication
UTRAN
UMTS Terrestrial Radio Access Network
V‐BLAST
Vertical Bell Laboratories Layered Space–Time
VLSI
very large‐scale integration
VoIP
Voice over Internet Protocol
VR
virtual reality
WAP
wireless application protocol
WGN
white Gaussian noise
WSN
wireless sensor network
ZF
zero forcing
ZP
zero padding

Part I
Mathematical Methods and Optimization Theories for Wireless Communications