LTE_and_beyond.pdf LTE (Long-Term Evolution)

LTE (Long-Term Evolution) is a fourth-generation (4G) wireless standard that provides increased network capacity and speed for cellphones and other cellular devices compared with third-generation (3G) technology.

LTE is a technology for wireless broadband communication for mobile devices and is used by phone carriers to deliver wireless data to a consumer's phone. Over the previous iteration of 3G, LTE provided high speed, higher efficiency, peak data rates and flexibility in bandwidth and frequency.

LTE offers higher peak data transfer rates than 3G, up to 100 Mbps downstream and 30 Mbps upstream. It provides reduced latency, scalable bandwidth capacity and backward compatibility with the existing Global System for Mobile communication (GSM) and Universal Mobile Telecommunications Service (UMTS) technology. The subsequent development of LTE-Advanced (LTE-A) yielded peak throughput on the order of 300 Mbps.

Although LTE is commonly referred to as 4G LTE, LTE is technically slower than 4G but still faster than normal 3G. For this reason, LTE may also be called 3.95G. While LTE speeds reach 100 Mbps, true 4G offers speeds up to 1,000 Mbps. However, different versions of LTE meet 4G speeds, such as LTE-A.

LTE eventually became universally available as a standard that is still commonly available in areas that don't yet have 5G.

LTE has a direct role in the development of the current 5G standard, called 5G New Radio. Early 5G networks, referred to as non-standalone 5G (NSA 5G), require a 4G LTE control plane to manage 5G data sessions. NSA 5G networks can be deployed and supported by the existing 4G network framework, lowering capital and operating expenses for operators rolling out 5G

1. LTE, WiMAX and 4G
Mobile Communication and Mobile
Computing Prof. Dr. Alexander Schill
http://www.rn.inf.tu-dresden.de
Department of Computer Science Institute for System Architecture, Chair for Computer Networks

2. LTE: Characteristics
•LTE = Long Term Evolution
•European implementation of IMT (International Mobile
Telecommunications) by ETSI (European Telecommunication
Standards Institute)
•Packet oriented propagation only
•High data rates
Up to 300 Mbit/s Downlink
Up to 75 Mbit/s Uplink
•Flexible frequency assignment
About 40 frequency ranges
Varying frequency blocks (1.4, 3, 5, 10 and 20 MHz)
•small latency of 5ms between mobile phone and conventional
telephone network
•optimized for travelling speeds of up to 15 km/h (up to
500km/h possible)
2

3. LTE – Reference Architecture
UE eNodeB S-GW P-GW
MME
LTE - Uu S1-U S5/
S8
S1-MME S11
HSS
S6a
PCRF
Gx
SGi
PSTN
eUTRAN Core
Network
•NodeB + RNC (3G) merged into evolved NodeB (eNodeB)
•Core network
Serving Gateway (S-GW)
Mobility Management Entity (MME)
PDN Gateway (P-GW)
Home Subscriber Server (HSS)
Policy Control and Charging Rules Function (PCRF)
3

4. LTE – User Equipment
•Examples of LTE-enabled devices
iPhone 5, Samsung Galaxy S3
LTE, Samsung LTE Stick
•Five device categories
Category 1 2 3 4 5
Peak data
rate Mbit/s
DL 10 50 100 150 300
UL 5 25 50 50 75
RF bandwidth 20 MHz
Modulation
QPSK, 16QAM QPSK,
16QAM,
64QAM
2 Rx diversity Assumed in performance requirements
2x2 MIMO
Not
support
ed
Mandatory
4x4 MIMO Not supported Mandatory
4

5. LTE: German frequency bands
•frequency spectrum of the digital dividend:
better building penetration & propagation features > higher range
•frequency spectrum of the IMT extension band:
Enough blocks for 20 MHz bandwidth > Higher data rate
12 MHz
820 MHz 832 MHz
5 MHz
frequency
block
(72 Mhz)
Duplex gap*
790 MHz 862 MHz
2570
MHz
2620
MHz
5 MHz
frequency
block
(190 Mhz)
10 x 5 MHz
blocks uncoupled
2500
MHz
2690
MHz
* The Duplex gap is meant as a fallback position for wireless production technology.
5

6. LTE: TDDand FDD
4 5 6 7 8 9
Special
Frame
UpPTS
0 1 2 3
subframe = 1 millisecond
0 1 2 3 4 5 6 7
8 9
Uplink (UL)
FDD
Downlink (DL)
6
Uplink (UL)
TDD
Downlink (DL)
D
w
P
T
S
G
u
a
r
d

P
e
r
i
o
d
•two versions of LTE provide solutions for coupled/uncoupled frequency
blocks
•transmitted signals divided into subframes (time units of 1 ms)
•FDD (Frequency division duplex) -separated frequency blocks for
UL/DL
•TDD (Time division duplex) – one frequency block alternately used for
UL/DL: - Downlink subframes, Uplink subframes and Special Frames
“Special Frame” = one subframe for each switching from down to up
link; contains DwPTS (Downlink Pilot Timeslot), GP (Guard Period –
avoids overlay of sent and received messages) and UpPTS (Uplink
Pilot Timeslot)

7. LTE: Modulation basics OFDM
LTE Modulation techniques are based on OFDM (Orthogonal frequency-
division multiplexing)
•in OFDM data is distributed over a large number of closely spaced
orthogonal subcarriers
(two subcarriers are orthogonal if the maximum amplitude of one
subcarrier is reached while the other subcarriers amplitude is
zero)
Subcarriers modulated with conventional modulation scheme
(QAM)
•Pro: robust against interference because interference on subcarrier does
not influence the whole frequency band, Improved spectrum efficiency
and lower bandwidth demand W with OFDM
•Con: expense for coding and decoding and therefore the power
consumption increases with the number of subcarriers
8
OFDM with 3 subcarriers
f f
FDM with 3 subcarriers

8. LTE: Modulation techniques
LTEs modulation techniques used for Downlink and Uplink
are based on OFDM with a special focus on simultaneous
access of multiple users
*OFDMA (Orthogonal frequency-division multiple access)
for Down Link
•subsets of subcarriers are assigned to individual users >
simultaneous (low data rate) transmission for several
users
*SC-FDMA (Single Carrier FDMA) for Up Link
•multiple access realized by insertion of coefficients on the
transmitter side before Fourier transformation, and
removing on the receiver side. Different users are
assigned to different coefficients (subcarriers). More
energy-efficient for battery-driven mobile devices.
9

9. LTE E-UTRAN Architecture
•Flat architecture:
eNodeBs form E-UTRAN
NodeB + RNC (3G)
merged into evolved
NodeB (eNodeB)
•eNodeB manages one or
several cells
•Responsibilities
IP header compression
Encryption
Radio resource
management
Connectivity to core
network
Bearer
management
UE mobility
Core
Network
E-UTRAN
eNode
B
eNode
B
eNode
B
MME S-GW MME S-GW
comm.
between
eNodeBs
signaling to

MMEs
bearer
path
10

10. LTE Interworking
UE E-UTRAN S-GW P-GW
MME
LTE - Uu S1-U S5/
S8
S1-MME
S11
3G-SGSN
S3 S4
non-3GPP networks
(CDMA2000, WiMAX,
…)
UTRAN
(GSM,
UMTS)
10
•Interworking and mobility with other 3GPP defined networks as
well as non-3GPP defined networks
•Service Gateway (S-GW) is mobility anchor for other 3GPP
networks

11. 11
LTE Advanced
•Specified as LTE Release 10
•Improved performance
Data rate up to 1 GBit/s
End-to-end delay 20 – 30 ms
•Enhancements
Carrier aggregation
up to 5 * 20 MHz -> 100MHz
Possible in contiguous and non-contiguous spectrum allocations
Multiple Input, Multiple Output (MIMO)
Up to 4 LTE antennas in LTE devices to use MIMO also for Uplink
Base stations can be equipped with up to 8 antennas
Support for relay node base stations
Connected to base station only
Improve signal quality at cell borders
Support of low power nodes such as picocells and femtocells
for crowded areas

12. 12
WiMAX / IEEE802.16
•WiMAX: Worldwide Interoperability for Microwave
Access, standardized by IEEE 802.16 and WiMAX-Forum
(more than 230 members, including AOL, Deutsche
Telekom, Intel, Microsoft, Nokia)
•IEEE 802.16 FBWA (Fixed Broadband Wireless Access) is
an alternative for broadband cable services like DSL;
frequency range: initially 10-66 GHz, in assumption of
LOS (line of sight)
•Enhancement IEEE 802.16a; frequency band: 2-11 GHz,
NLOS (non line of sight)
•Enhancement IEEE 802.16e for MBWA (Mobile
Broadband Wireless Access); frequency band: 2-6 GHz,
NLOS

13. 13
WiMAX/IEEE 802.16: overview
Standard 802.16 802.16a 802.16e
Spectrum, GHz 10-66 2-11 2-6
LOS-condition LOS NLOS NLOS
Bit rate, MBit/s 32-134 <75 (extensions
up to 365)
15 (with
further
extensions)
Range, km 2-5 7-10
max. 50 (cellular)
2-5
Channel
bandwith,
MHz
20, 25 and
28
Variable: 1,5–20 1,5 -20
Modulation QPSK,
16QAM,
64QAM
OFDM, QPSK,
16QAM,
64QAM
OFDM, QPSK,
16QAM,
64QAM
approved 2001 2004 2006
(N)LOS – (Non) Line-of-Sight

14. 14
802.16 Physical Layer
SpecificationFrequency
band
Channel
bandwidth
Duplex
method
Modulatio
n
Line-of-
Sight
WirelessMAN-SC 10-66 GHz
Licensed
bandwidth
20, 25,
28 MHz
TDD, FDD Single
carrier
LOS
WirelessMAN-
SCa
2-11 GHz
License
d
bandwid
th
3,5, 7, 10,
20 MHz
TDD, FDD Singl
e
carri
er
NLOS
WirelessMAN-
OFDM
2-11 GHz
License
d
bandwid
th
variabl
e
1,25-
20
MHz
TDD, FDD OFDM NLOS
WirelessMAN-
OFDMA
2-11 GHz
Licensed
bandwidth
variable
1,25-28
MHz
TDD, FDD OFDMA
(“multipl
e
access”)
NLOS
WirelessHUMAN 2-11 GHz
License
-
free
10, 20 MHz TDD OFDM,

OFDM
A
NLOS

15. 15
802.16 Medium Access
•TDMA (Time Division Multiple Access)
Each communication channel gets fixed slot for data
transmission
•DAMA (Demand Assigned Multiple Access)
2 Phases:
Reservation: every station tries to acquire slot for
each transmission phase (collision possible)
Data transmission: within reserved slot
guaranteed
collision free transmission
•Duplex connection
FDD (Frequency Division Duplex): simultaneous use
of
different frequencies
TDD (Time Division Duplex): Switching between up-
anddownlink on the same frequency

16. WiMAX: Cellular backbone
Network
Point to Point
Backbone
Point to Multipoint
UMTS cell
WiMAX cell
802.16
PHY
802.16
OFDM-
PHY
e.g Gigabit
Ethernet
16

17. 1)Last Mile or
2)Point to Multipoint (PMP) network (see bellow)
•Base Station (BS) is the central point for the
Mobile Stations (MS)
•Sending in Downlink-direction: Broad-, Multi-,
Unicast
•Connection of a MS to BS is characterized
via Channel ID (CID),
Channel id gives the possibility for the BS to receive multicast
messages
802.16 Network topologies (1&2)
22
MS/BS
MS/BS
BS
MS
MS
MS MS
Network

18. 802.16 Network topologies (3)
3)Mesh network
•MS can communicate directly
•Mesh BS: connected with a network outside the mesh
•other differentiation
neighbor: direct connection to a node
neighborhood: all other neighbors
extended neighborhood: remote neighborhoods
23
Mesh MS
Mesh BS
Mesh MS
Mesh MS
Mesh MS
Mesh MS
Mesh MS
Network

19. 19
MBWA (Mobile Broadband Wireless Access);
802.20 (1)
•Working Group 802.20 originated from 802.16
goal: Specification of PHY and MAC for Packet-based MBWA-
System
Should close the gap between WLAN and slower but highly
mobile networks (UMTS)
•features
variable cell size
Handover- and Roaming-mechanism
Velocity up to 250 km/h
Transport of IP-data traffic
QoS on transport layer
Licensed bands below 3,5 GHz, variable bandwidth
NLOS, for in- and outdoor
TDD, FDD, Half-Duplex FDD
More than 100 simultaneous sessions per cell
End to End Security, AES

20. (1)<100m,
(2)~500m,
(3)>1km 20
UMTS/HSPA/HSPA+ WiMAX MBWA LTE
MobilityHandover, Roaming ---------------- Handover, Roaming, Mobile IP ---
Max Speed300 km/h 120 km/h 250 km/h 500 km/h
Switching typecircuit and packet ---------------- Packet switching ----------------
Peak
data rates
Down
Link
2/14,4/28 Mbit/s
(5MHz channel)
365 Mbit/s
(2x
20MHz
channel,
variations)
–
100 - 300 Mbit/s
(1.4-20 MHz
channel)
Cell sizes
pico
(1)-, micro
(2)-,
macro
(3)-cells
variable
pico
(1)-,
micro
(2)-,
macro
(3)-cells
pico
(1)-, micro
(2)-,
macro
(3)-cells
QoS
End-to-end QoS
Different classes
End-to-end
QoS
Different
classes
End-to-end
QoS
End-to-end QoS
Different classes
Scalability---------------- variable data rate ~ Multiple users per BS --------------
Air Interface
CDMA
adaptive Modulation
MIMO
OFDM(A),
adaptive
Modulation
MIMO
OFDM
Adaptive
Modulation
OFDM, SC-FDMA
adaptive
Modulation
MIMO
SecurityAES AES, X.509AES SNOW 3G
Technology comparison pre-4G

21. 21
4G requirements
•high mobility ?????? Handover, Roaming,
velocity up to 300 km/h
•switching technique ?????? pure packet switching
•integratedmulti-media-services ?????? VoIP, TVoIP, VoD,
Streaming
•high data rate (1Gbit/s) ?????? even at high mobility should
be like DSL
•Size of cell ?????? variable and scalable
•QoS ?????? prioritization of specific data packages
•scalability ?????? available and reliable with many users
•air interface?????? OFDM (better spectrum efficiency)
•security ?????? up to date standards (e.g. AES)
•Extension / integration of UMTS and WLAN approaches

22. 22
Technology comparison 3G to 4G
LTE (3G) LTE Advanced (4G)
Peak data rate
Down Link (DL)
300 Mbit/s 1 Gbit/s
Peak data rate
Up Link (UL)
75 Mbit/s 500 Mbit/s
Transmission
bandwidth DL
20 Mhz (max.) 100 Mhz
Transmission
bandwidth UL
20 Mhz (max.) 40 Mhz (requirements as
defined by ITU)
Coverage
Full performance up to
5km
Same as LTE requirement.
Should be optimized or
deployed in local areas/micro
cell environments.
Scalable
bandwidths
1.4, 3, 5, 10 and 20 MHz 20-100 MHz
Scalability
variable data rate
Multiple users per BS
variable data rate
Multiple users per BS
Capacity
200 active participants
per cell at 5 MHz
3 times higher than that in
LTE

23. Summary: Data rates and mobility
High-speed
/Wide-area
Medium-speed
/Urban area
Walking
/Local area
Standing
/Indoors
2G
Source:
www.3g.co.uk
Mobilit
y
0.1
23
1 10 100 200 1000
Bitrate, MBit/s

24. 5G Definition

25. 5G Definition
1.Peak Data Rate: max rate per user under ideal conditions. 10
Gbps for mobiles, 20 Gbps under certain conditions.
2.User experienced Data Rate: 95% Rate across the coverage
area per user. 100 Mbps in urban/suburban areas. 1 Gbps
hotspot.
3.Latency: Radio contribution to latency between send and
receive
4.Mobility: Max speed at which seamless handover and QoS is
guaranteed
5.Connection Density: Devices per km
2
6.Energy Efficiency: Network bits/Joule,
User bits/Joule
7.Spectrum Efficiency:
Throughput per Hz per cell
8.Area Traffic Capacity:
Throughput per m
2

26. 5G Additional Capabilities
1.Spectrum and Bandwidth Flexibility: Ability to operate at
different frequencies and channel bandwidths
2.Reliability: High availability
3.Resilience: Continue working in face of disasters
4.Security and Privacy: Confidentiality, Integrity, Authentication,
Protection against hacking, denial of service, man-in-the-middle
attacks
5.Operational Lifetime: Long battery life

27. 5G Application Areas
Three Key Application Areas:
1.Enhanced Mobile Broadband (eMBB): Better mobile phones and
hot spots. High data rates, high user density. Human centric
communications
2.Ultra-Reliable and Low-Latency Communications (URLLC):
Vehicle-to-Vehicle communication, Industrial IoT, 3D Gaming.
Human and Machine centric communication
3.Massive Machine Time Communications (mMTC): Very
large number of devices, low data rate, low power. IoT with long
battery life time. Addition to GSM, LoRa, Zigbee, etc. Machine-
centric communication.

28. 5G Applications

29. 5G Spectrum
World Radio-communications Conference (WRC)
determines the spectrum requirements
WRC-2000 identified the spectrum required for 3G
WRC-2007 identified the spectrum required for 4G
WRC-2019 is expected to finalize spectrum required for
5G
Two Frequency Ranges (FRs)
FR1: Sub 6-GHz. Several new bands in this range.
FR2: 24.25-52.6 GHz (mm-Waves)
 Good for high throughput in small cells

30. 5G Health Concerns
5G may need higher power transmission levels than
those allowed currently by health regulations in
various countries
Federal Communications Commission (FCC) and
International Commission on Non-Ionizing Radiation
(ICNIRP)
Specify max absorption rate in W/Kg up to 6 GHz
Specify max incident power density W/m
2 for 6-
10 GHz (absorption becomes difficult to measure
in this range)
5G industry wants limits
increased. Health activists want
limits decreased.
 Current debate