The slides include the introduction to vehicular technology, two radio access vehicular technology DSRC & C-V2X. Also Vehicular Named Data Networking (V-NDN) along with research challenges and future research directions is presented.

1. Next Generation V2X
Technology
DongkyunKim
School of ComputerScienceand Engineering
http:// monet.knu.ac.kr
Slide 1

2. Contents
Introduction to Vehicular
Communication
Vehicle Communication Standard
IEEE
3GPP
Two Radio Access Technologies
Dedicated Short Range
Communication (DSRC)
802.11p
Evolution to 802.11bd & Challenges
Cellular Vehicle to Everything (C-
V2X)
C-V2X Release 14
Evolution to New Radio (NR-V2X) Release 16 &
Challenges
Vehicular Named Data Networking
(V-NDN)
Introduction to NDN
Introduction to V-NDN
Challenges & Future Direction

3. What is Vehicular Communication?
Wireless Communication Vehicular Communication
Use wireless channel for communication.
Single broadcast domain.
Also use air as the medium for communication.
Vehicles communicate with other vehicles a.k.a V2V.
Vehicles also communicate with the infrastructure
(RSU) a.k.a V2I.
Slide 3

4. Two Radio Access Technologies: DSRC and Cellular V2X
• DSRC / 802.11p
 802.11bd
(IEEE 802.11 Task Group)
• LTE-Cellular V2X
New Radio (NR)
(3GPP)

5. Vehicular Communication Standards
DSRC & WAVE C-V2X
Dedicated Short Range Communication.
Use IEEE 802.11 or WiFi standards.
Developed by IEEE.
Cellular Vehicle to Everything.
Use Cellular Networks such as LTE and 5G.
Developed by 3GPP.
Slide 5

6. DSRC-BASED STANDARDS

7. DSRC & WAVE
PHY and MAC layers are defined in 802.11p
which was derived from 802.11a.
11p mainly focuses on:
- Vehicular Safety,
- Better traffic management
11p was developed in 2010, since then many
advances have been made in the 802.11
protocols.
New techniques of 802.11 n/ac/ax can enhance
802.11p.
IEEE 802.11bd Task Group was created in Jan,
2019. Final standards – Dec, 2021.
Slide 7

8. DSRC Spectrum
 In 1999, FCC allocated 75 MHz of bandwidth (5.850-5.925 GHz).
 Seven 10 MHz wide channels.
 One control channel (CCH) – System control and safety-related message.
 Four service channels (SCH) – Non-safety messages.
 Two channels at the end reserved for special uses.
Slide 8

9. 802.11p Features Overview
WAVE MODE
 Instantaneous data exchange without any
overhead for safety messages.
 Use wildcard BSSID in the MAC header.
WAVE BSS
 Used for non-safety application, such as digital
map download.
 Station joins the BSS by only receiving a WAVE
advertisement.
 A station of a WBSS can still transmit and receive
safety messages using wildcard BSSID.
Slide 9
Station AP
Safety Message
Set wildcard BSSID

10. Objectives
 Relative velocities up to 200 km/hr.
 Response times of around 100 msec.
 Range of up to 1000 meters.
802.11p
 Twice the MAC throughput of 802.11p with
relative velocities up to 500 km/hr.
 Twice the communication range of 802.11p.
 Additionally:
 Interoperability.
 Coexistence.
 Backward compatibility.
 Fairness.
802.11bd

11. 802.11bd: Midambles
 Channel varies within the frame duration.
 Using only preamble to estimate the channel for the whole frame is not sufficient.
 802.11bd proposed to use midambles to address this issue.
 Frequency of midambles will depend on factors like modulation, error control, Doppler
spread, etc.
11bd: Insertion of midambles for improved channel estimation.
Preamble Data_1 Midamble Data_2 Midamble Data_3
Preamble Data_1 Data_2 Data_3 Data_4
802.11p uses only preamble
Slide 11

12. 802.11bd: Retransmission
 To improve reliability, TGbd proposes retransmission mechanism.
Additional messages will be
filtered out by upper layer.
Additional messages will be
filtered out by data link layer.
Retransmissions are reduced as
channel load increases (based on
Channel Busy Ratio measurement) to
avoid congestion.
Slide 12

13. 802.11bd: OFDM Numerologies
 For the same signal bandwidth, different OFDM tone
numerology can be designed.
 Smaller tone spacing (TS) can achieve better OFDM
efficiency, (same cyclic-prefix (CP) duration).
 But observes worse ICI, and larger channel variation
across OFDM symbols.
 OFDM numerology candidates:
 TS=156.25kHz, FFTsize=64
 Max CP of 1.6us
 TS=78.125kHz, FFTsize=128
 Max CP of 3.2us
 TS=39.0625kHz, FFTsize=256
 Max CP of 6.4us
Slide 13
Efficiency  80%
CP
OFDM
Symbol
1.6us 6.4us
8us
CP OFDM Symbol
1.6us 12.8us
14.4us
CP
1.6us 25.6us
27.2us
OFDM Symbol
Efficiency  89%
Efficiency  94%

14. 802.11bd: Dynamic Bandwidth Operation
 11bd STAs sense a 10 MHz Primary Channel
 Follow back-off rules of 11p without modifications.
 Transmission
 non-primary channel idle  20 MHz 11bd PPDU can be transmitted.
 If not (i.e., busy)  10 MHz 11bd PPDU will be transmitted.
 Reception
 11bd STAs  Use signaling information of the 10 MHz primary channel.
 Then decides whether to use the 20 MHz channel or not.
11bd PPDU
(20MHz)
IFS + Back off IFS + Back off
IFS TBD
10 MHz
10 MHz
Primary
Channel
Non-Primary
Channel
B U S Y
11bd
STA
11bd PPDU
(20MHz)
Slide 14

15. 802.11bd: Other Features
 Transmit same symbol twice over far
apart subcarriers.
 Modulation order must be doubled to
maintain same throughput.
Dual Carrier Modulation
 802.11bd will re-use 802.11p’s
contention parameters for different
EDCA categories.
Fair Channel Access
AC CWmin CWmax AIFS (us)
AC_VO 3 7 58
AC_VI 7 15 71
AC_BE 15 1023 110
AC_BK 15 1023 149
1 1
2 2
3 3
4 4

16. 802.11bd: Other Features
 11p supports multichannel operations over
single radio by using 1609.4.
 50ms for control channel and 50ms for
service channel.
 11bd will use multiple radios.
Multi-channel operation
 802.11bd use 60GHz  very high throughput.
 at low MCS.
 Limited to short range communication.
mmWave
CCH Interval
50ms
SCH Interval
50ms
Guard Interval
11p
STA
Single
Radio
Control Channel
Service Channel
11bd
STA
Radio 1
Radio 2

17. 802.11bd: Challenges
 Interoperability & Backward Compatibility
 Imposes certain constraints on the design of PHY and MAC layers.
 Multiple antenna schemes like space time block coding violates the interoperability
requirement.
 Coexistence
 A mechanism is required for an 11bd device to notify other 11bd devices about its capabilities.
 Otherwise, even if there are no 11p devices, 11bd devices continue to transmit using 11p
format.

18. Introducing Cellular V2X (C-V2X)
Part of Release 14 of Global 3GPP Standard (2017)
Builds upon existing LTE connectivity platform for
automotive (LTE Rel.12)
Enhances LTE Direct for V2X direct communications
Leverages existing LTE networks for V2X network
communications

19. 6
V2X: Giving vehicles the ability to communicate with each other and beyond
Vehicle-to-
vehicle (V2V)
e.g. collision avoidance safety systems
Vehicle-to-
infrastructure (V2I)
e.g. traffic signal
timing/priority
Vehicle-to-network (V2N)
e.g. real-time traffic / routing, cloudservices
Vehicle-to-pedestrian
(V2P)
e.g. safety alerts to
pedestrians, bicyclists

20. C-V2X: LTE-Uu / PC5 Interface
PC5 Interface Uu Interface
V2V Direct Communication Network Communication (V2N)
Proximal Direct Communication
100s of meter
Operates in and Out of Coverage
Wide Area Network
Communication
Leverages Existing LTE Network
Communication

21. C-V2X: Physical Layer
•C-V2X utilizes single-carrier frequency-division
multiple access
•Supports 10- and 20-MHz channels.
• Each channel is divided into subframes, resource blocks
(RBs), and subchannels.
•An Resource Block (RB) is the smallest unit of
frequency resources
• It is 180 kHz wide in frequency (12 subcarriers of 15 kHz).
•C-V2X defines subchannels as a group of RBs in the
same subframe, and the number of RBs per
subchannel can vary.
•Subchannels are used to transmit data and control
information.
• The data is transmitted over (PSSCH), and the sidelink
control information (SCI) transmitted over physical sidelink
control channels (PSCCH)

22. C-V2X Mode4 : Semi-Persistent Scheduling (SPS)
Mode 4
Out of Coverage Mode
Resources are Scheduled by UE
PC5- Direct
Communication
Semi-Persistent
Scheduling (SPS)
Message Packet generated at time ‘n’
• Step 1: Transmitting vehicle will identify all the
subframe resources it could reserve from the
selection window.
• Step 2: Vehicle identifies the list of available
subframe resources (LA). LA excludes
• all those resources based on the RRC field received
in SCI that shows the resources reserved
• those subframes in which the RSSI is above then
the defined threshold
• Step 3: From the LA it will create the list (LC) of
candidate subframe resources (CSRs).
• The LC from the list LA selects the 20% of subframes
identified in step 1 that have least average RSSI

23. Autonomous Resource Selection in SPS
Time
Frequency
Subchannel
Sensing Window
nth - 1
subframe
nth - 1000
subframe
1 sec
Sidelink
subchannel
Selection Window
n + T1
n
Resource
selection
n + T2
RRI

24. C-V2X Mode 3:
• The selection of subchannels is
managed by the base station or
evolved NodeB (eNB)
• As opposed to mode 4, the
standards do not specify a resource
management algorithm for mode 3
• Each operator can implement its own
algorithm
Mode 3
In-Coverage Mode
Resources are Scheduled by
enodeB
PC5- Direct
Communication

25. Evolving C-V2X towards 5G-NR
High Throughput
Lower Latency
High Reliability
Coexistence
C-V2X
Evolution to 5G NR
5G -NR

26. Unicast, Multicast and Broadcast Transmission
•C-V2X supports broadcast mode only
•NR supports unicast, multicast and broadcast transmission mode
•Transmission mode defined at PHY layer
• if a packet belongs to a unicast or groupcast mode, then non-participant UEs does
not decode
Unicast
Broadcast
Unicast
Groupcast

27. NR Numerologies

28. NR Numerologies

29. Mini Slot / Multi Slot
•One Slot is comprised of 14 OFDM symbols
• Slot length depends on SC spacing
• (1ms for 15 kHz SC to 0.125ms for 120 kHz SC)
• Mini-slot (2, 4, or 7 symbols) can be allocated for shorter transmissions (NR)
• Slots can also be aggregated for longer transmissions
0 1 2 3 4 5 6 7 8 9 10 11 12 13
15 kHz SC
0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6 7 8 9 10 11 12 13
30 kHz SC
60 kHz SC
Slot Slot Slot Slot
Slot Slot Slot Slot Slot Slot Slot Slot
120 kHz SC

30. Multiplexing of Physical Sidelink Control Channel
(PSCCH) and Physical Sidelink Shared Channel (PSSCH)
C-V2X 5G-NR

31. Pre-emptive Scheduling
UE #1 is scheduledon the
shared channel
Scheduled transmission time for UE #1
Latency critical data arrives for UE #2, and is
immediately scheduled by puncturing the ongoing
transmission to UE #1, rather than waiting for its
completion, i.e.avoiding additional latency.
UE #1 receives the scheduled transmission, where
part of it ispunctured.
shared
radio
channel
Resources
scheduled for
UE #1
Resources
scheduled for
UE #2

32. Coexistence of NR & C-V2X
FDM Approach:
•Uses same ITS band for NR and C-V2x
• Latency critical use cases
• However, Out of band emissions create interference
• Total permissible radiated power should not exceed
TDM Approach:
•Two RATs occur in different channels and at different time instants.
• maximum permissible transmission power can be used
• disadvantageous for latency critical use-cases

33. VEHICULAR NAMED DATA NETWORKING
(V-NDN)

34. Networks Today
Today’s Networking:
◦ Device Centric
◦ Communicate by addressing the device.
◦ >90% of traffic is accessing different kind of Content.
◦ Inefficient for Content/data dissemination.
◦ Multicast ~ at huge cost of Network resources.
◦ Addressing ~ Inefficient : DNS, IPv4/6, etc. to identify devices.
◦ Service Discovery ~ Many protocols, with no standard.
◦ Mobility? ~ Achievable but not inherent in today’s networks.
◦ Security? ~ Connection: IPSec, VPN, SSL, but not Content ….
Result --> spam.

35. Problems of IP Networking
Does not easily support
◦ Multipath forwarding
◦ Mobility
◦ Multicast
Insufficient & complex security
mechanisms
Application oriented (e.g. for IoT)

36. Causes of IP Networking Problems
Designed for communication and not distribution network: host-centric packet
delivery
Channel-based security

37. What is NDN?
•Distribution-based network: more general than communication networks
•Data-Centric rather than host centric as current IP based network
•Instance of Information-Centric Networking (ICN)
•Focus on fetching data identified by given name.
•Name of a packet is used to make forwarding decisions
•Router caches received data and use it to satisfy future requests

38. NDN Solutions to IP Networking Problems
Secure data instead of channels
Name data directly instead of host
Support stateful forwarding with opportunistic caching
Use the same name and data unit at both application and network layers

39. Hour-Glass: Current Internet vs ICN

40. Types of Packets in NDN

41. Names in NDN
Names are opaque to the network
Hierarchical namespaces are essential
Deterministically construct the name for dynamically generated data
Globally unique names: for data that are to be retrieved globally
Interest selectors with longest prefix matching retrieve desired data

42. Forwarding Process at an NDN Node
• Like IP networking, routing
protocols are used to
populate FIB
• However, they use names
prefixes instead of IP
prefixes
• NDN routing protocol:
NDN based link-state
routing (NLSR) protocol

43. Forwarding Interest packet when Data has not been
cached
FIB
CS
CS
CS
s1 s2
s3
1
2
3
1
2
3
4
1
2
3
4
1
5
2
PIT
v: 3
v: 1
PIT FIB
v: 5
CS PIT FIB
v: 2
PIT FIB
v: 4
v
v
v: 1
v: 1
v: 1, 3
C1
C2
C3
P
s4

44. Forwarding of the Data packet
FIB
CS
CS
CS
s1 s2
s3
1
2
3
1
2
3
4
1
2
3
4
1
5
2
PIT
v: 3
v: 1
PIT FIB
v: 5
CS PIT FIB
v: 2
PIT FIB
v: 4
v
v
v: 1
v: 1, 3
v
v
v
C1
C2
C3
P
s4

45. Forwarding Interest packet when Data packet has been
cached
FIB
CS
CS
CS
s1 s2
s3
1
2
3
1
2
3
4
1
2
3
4
1
5
2
PIT
v: 3
PIT FIB
v: 5
CS PIT FIB
v: 2
PIT FIB
v: 4
v v
v
v
v
v v: 2
C1
C2
C3
P
s4

46. Vehicular Networks
• Highly dynamic topology.
• Unpredictable link lifetime.
• Safety and Non-Safety applications.
• Large data requirements.
• Delay constraints, etc.
• With/Without infrastructure support.
• Data ranges from short messages to Large video contents.
V2V
Communication
V2I / I2V
Communication

47. V2V
Communication
V2I
Communication
Name Prefixes Out.
Face(s)
FIB
Names In.
Face(s)
PIT
CS
Maintained at each
Vehicle
Name each content
• Maintaining Names (specially in PIT)
• Data Structure with minimum space….
• Fast addition and deletion of names ….
• Searching Names from PIT and FIB.
• Speed and accuracy.
• Forwarding based on the search result.
Vehicular Named Data Networks (V-NDN)
1/10/2016

48. Node D Node E
Node C
Node B
Node A
CONSUMER
PROVIDER
Vehicular Named Data Networks
1/10/2016

49. V-NDN Applications
• Real-time Traffic Information System
• Smart and Priority Parking
• Smart Mass Transit
• Smart Electric Vehicle Charging
• (SCI) Safdar H. Bouk, Syed Hassan Ahmed, Dongkyun Kim, and Houbing Song "Named Data Networking based ITS for Smart Cities,“ IEEE Communications Magazine,
January 2017.
• (SCI-E) Syed Hassan Ahmed, M. A. Yaqub, S. H. Bouk, and Dongkyun Kim “SmartCop: Enabling Smart Traffic Violations Ticketing in Vehicular Named Data Networks” Mobile
Information Systems, May, 2016.

50. Challenges
VNDN
Routing /
Forwarding
Naming
Caching
Mobility
Security
CS, PIT, FIB
Content
Management
Control
Overhead

51. Challenges in V-NDN & Future Directions
• Vehicle Mobility
• Consumer Vehicle moving away from the Producer Vehicle
• Providing cache storage at the Edge for efficient retrieval of content
• Interest Flooded in the network
• Leads to broadcast storm
• Directional forwarding may can reduce the broadcast storm
• Limited Cache Storage
• Cache freshness: Cache have to update itself with latest content
• Applying machine learning for dynamic cache storage size

52. Conclusions
Current self-driving cars rely on camera vision technologies
 Technologies for V2V communications : Essential
 Vehicular NDN can be a network solution to providing a lot of QS-
related services on the roads
Thank for your attention !
Q & A