UNIT- III�In-Vehicle Communication & Connectivity

Syllabus

• Need for communication between vehicle components
• Basics of CAN, LIN, and Ethernet (simple explanation with diagrams)
• Intro to V2V and V2X communication
• Role of IoT in SDVs
• Simple examples of connected features (e.g., connected infotainment, remote lock/unlock)

��Introduction & Need for Communication Between Vehicle Components��

• Vehicles integrate multiple electronic systems (engine, safety, infotainment, etc.).
• Reliable communication enables safety, comfort, diagnostics, and automation.
• Uninterrupted data exchange is essential for autonomous and connected features

Basics of CAN (Controller Area Network)

• CAN connects multiple ECUs (Engine Control Units), enabling reliable real-time data transfer.
• Bus uses differential signaling on two wires: CAN High and CAN Low.
• CAN frames contain message ID, data, and error-checking fields.

https://www.watelectronics.com/controller-area-network-protocol/

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Basics of CAN (Controller Area Network)

The CAN Bus is the highway itself.

The CAN Bus Transceiver is the on-ramp and off-ramp system, converting your car's digital navigation data into physical movement on the road and vice versa.

The CAN Protocol Machine is the traffic management system, ensuring cars don't crash (arbitration) and rerouting them if there's a problem (error handling).

The Acceptance Filters are like the signs at your destination's parking lot—they only allow cars with a specific parking permit to enter.

The Receive Buffer is the parking lot where authorized cars wait until the owner comes to get them.

The Transmit Buffers are like your garage, where you prepare messages (cars) to be sent out onto the highway.

The Host Controller Interface is you, the driver, managing the cars in your garage and deciding which ones to take from the parking lot. The Interrupt is your car's GPS alerting you that a new message has arrived at the destination.

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BUS Idle: This is the state of the bus when no messages are being transmitted. It signifies the end of one message and the readiness for another.

SOF (Start of Frame): A single dominant bit that marks the beginning of a message. It synchronizes all the nodes on the bus.

Arbitration Field: This field determines which message gets priority on the bus. When multiple devices try to transmit at the same time, they all send this field, and a process called bit-wise arbitration occurs. The message with the lower numerical Identifier value has higher priority and wins the arbitration.

Identifier: A unique 11-bit identifier that specifies the message's content and priority. For example, a message with the identifier 0x100 might contain engine temperature data, while a message with 0x200 might contain wheel speed data.

RTR (Remote Transmission Request) bit: A single bit that indicates if the frame is a data frame (RTR = 0) or a remote request frame (RTR = 1). A remote request frame is used to request a data frame from another node.

IDE (Identifier Extension) bit: This bit is '0' in a standard format frame, indicating that no extended identifier is present.

r (Reserved) bit: This bit is reserved for future use and is always '0'.

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DLC (Data Length Code): A 4-bit field that specifies the number of bytes in the Data Field. It can indicate a length from 0 to 8 bytes.

Data Field: This field contains the actual data being transmitted, with a length from 0 to 8 bytes, as specified by the DLC.

CRC Field (Cyclic Redundancy Check): Used for error detection.

CRC Sequence: A 15-bit field containing the checksum calculated from the previous fields. The receiving node calculates its own checksum and compares it to this value. If they don't match, an error is detected.

DEL (Delimiter) bit: A single recessive bit that separates the CRC Sequence from the ACK Field.

ACK Field (Acknowledgment): This field confirms that the message was received correctly by at least one other node.

ACK Slot: A single recessive bit transmitted by the sender. Any receiver that successfully receives the message overwrites this bit with a dominant bit, providing a collective acknowledgment.

DEL (Delimiter) bit: A single recessive bit that separates the ACK Field from the EOF.

EOF (End of Frame): A 7-bit field of recessive bits that marks the end of the frame.

ITM (Intermission): A 3-bit field of recessive bits that acts as a buffer between frames. It ensures a minimum idle time before the next message can start.

Bus Idle: The bus returns to its idle state, ready for the next SOF bit to signal a new transmission.

Basics of LIN (Local Interconnect Network)

• LIN is a cost-effective, slower network for connecting less critical nodes (e.g., window motors, seat controls).
• LIN uses a master-slave architecture—master sends header, slave responds with data.
• Typical for body electronics and simple commands.

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Steering wheel: Cruise control, wiper, climate control, radio

Comfort: Sensors for temperature, sun roof, light, humidity

Power train: Sensors for position, speed, pressure

Engine: Small motors, cooling fan motors

Air condition: Motors, control panel (AC is often complex)

Door: Side mirrors, windows, seat control, locks

Seats: Position motors, pressure sensors

Other: Window wipers, rain sensors, headlights, airflow

https://www.csselectronics.com/pages/lin-bus-protocol-intro-basics

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Automotive Ethernet Overview

• Ethernet enables high-speed data transfer, supporting ADAS, infotainment, and cameras.
• Automotive Ethernet uses single twisted pair cables for light weight and cost.
• Standards: 100BASE-T1 (100Mbps), 1000BASE-T1 (1Gbps), suitable for backbone and high-data needs.

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Data transfer Example

National Institute of Information and Communications Technology (NICT) in collaboration with Sumitomo Electric and European partners. 1 petabit per second is equal to 1,000,000 gigabits per second.

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Introduction to V2V and V2X Communication

• V2V (Vehicle-to-Vehicle): Cars share speed, position, and braking info for collision avoidance.
• V2X (Vehicle-to-Everything): Communication extends to infrastructure (V2I), network (V2N), pedestrians (V2P).
• Enables cooperative driving, smart traffic, increased safety.

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V2V (Vehicle-to-Vehicle)

• Concept: Cars "talk" directly to each other.

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• What they share: Speed, position, direction, and braking status

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• Main Goal: Prevent collisions by seeing "around corners" and beyond a driver's sight.

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• Example: A car receives a signal that the vehicle ahead has suddenly braked, even if it's hidden by a truck. The driver is instantly alerted.

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V2X (Vehicle-to-Everything)

• Concept: The vehicle communicates with everything in its environment. V2V is a part of this larger system.
• V2I (Vehicle-to-Infrastructure): Car talks to traffic lights, toll booths, and road sensors.
• Example: A car receives a signal from a smart traffic light, telling it to adjust speed to avoid waiting at a red light.
• V2N (Vehicle-to-Network): Car connects to a cellular network or cloud.
• Example: The car downloads real-time traffic updates or software patches over the air.
• V2P (Vehicle-to-Pedestrian): Car talks to a pedestrian's smartphone or wearable device.
• Example: The car is alerted to a pedestrian about to step into the crosswalk, even if the pedestrian is not yet visible.

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Why V2X Matters

• Enables Cooperative Driving: Vehicles work together to optimize traffic flow and safety.
• Creates Smart Traffic: Reduces congestion and emissions by optimizing signal timing and routing.
• Increases Safety: Provides drivers and autonomous systems with a complete, 360-degree view of the environment, significantly reducing accident risk.
• https://youtu.be/3z09fCqmILU?si=oVxjreMxw-CKCC92
• https://youtu.be/yceuUthWz9s?si=BByRrjgx4QKv4YPc

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What is IoT (Internet of Things)?

The Internet of Things (IoT) refers to a network of physical devices ("things") that are embedded with sensors, software, and connectivity so they can collect, exchange, and act on data through the internet.

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Examples of IoT devices

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Smart Home → smart bulbs, thermostats, CCTV cameras, voice assistants.

Wearables → smartwatches, fitness trackers.

Automotive → connected cars, vehicle tracking, predictive maintenance.

Healthcare → remote patient monitoring, smart medical devices.

Industrial (IIoT) → factory sensors, robotics, predictive maintenance.

IoT = Things (devices) + Internet (connectivity) + Data (insights & action).

Hypertext Transfer Protocol

(Message Queuing Telemetry Transport)

ROLE OF IOT IN SDVs

IoT is the backbone of SDVs, enabling real-time connectivity, safety, autonomous functions, user personalization, and smart city integration.

Safety & Predictive Maintenance

Detects potential faults before failure (e.g., low battery, overheating).

Sends alerts for preventive maintenance, reducing breakdowns and accidents.

Connectivity & Communication

Enables Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication.

Supports V2X (Vehicle-to-Everything) for integration with pedestrians, traffic signals, and smart roads.

Real-Time Data Collection

IoT sensors collect continuous data on engine health, tire pressure, battery status, braking, speed, GPS location, etc.

Provides valuable input for decision-making in autonomous driving.

Autonomous Driving Support

IoT provides high-resolution sensor data (cameras, LiDAR, radar, ultrasonic sensors).

Enables ADAS (Advanced Driver Assistance Systems) like lane-keeping, collision avoidance, and adaptive cruise control.

CONTINUE…

Security & Compliance

• Monitors driver behavior and vehicle compliance with safety regulations.
• Supports cybersecurity measures for connected cars.

Enhanced User Experience

• Seamless smartphone integration (remote lock/unlock, climate control, navigation).
• Personalized infotainment and comfort features.
• Over-the-Air (OTA) updates keep features up to date.

Fleet & Mobility Management

• IoT helps in real-time vehicle tracking, fuel/energy optimization, and route planning.
• Essential for ride-sharing, logistics, and fleet operators.

Smart City Integration

• Connects vehicles to smart traffic lights, parking systems, EV charging stations.
• Enables efficient traffic management and congestion reduction.

Data-Driven Insights

• Cloud-based analytics process IoT data for performance optimization.
• AI + IoT enable self-learning vehicles that adapt to user behavior.

Examples of Connected Features in SDVs

Connected Infotainment

Real-time navigation, music streaming, voice assistants.

Remote Lock/Unlock – Control vehicle access using a smartphone app.

Remote Climate Control – Start AC/heater before entering the car.

Vehicle Health Monitoring – Get alerts for tire pressure, battery, or service needs.

Over-the-Air (OTA) Updates – Software updates without visiting service centers.

Integration with Smart Devices – Sync with smart home devices (garage door, lights).

Emergency Assistance – Automatic SOS alerts in case of accidents.