The document discusses the Wireless Controller Area Network (WCAN) protocol. WCAN is based on the Controller Area Network (CAN) protocol but makes it wireless. It uses a token frame scheme to transmit messages in a ring network topology. Simulation results showed that WCAN can achieve higher throughput and packet delivery ratios than IEEE 802.11 in some scenarios, especially when the packet transmission rate is increased. WCAN is suitable for real-time industrial automation and vehicle applications where microcontrollers need to wirelessly communicate with each other.

1. Wireless Controller Area
Network (WCAN)
Presented by
SHUBHAM CHAKRAVARTY
(19MTES09)

2. Contents
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 Introduction
 General Aspects
 Protocol Features
 WCAN Protocol
 Applications
 Conclusion
 References

3. Introduction
 The Controller Area Network (CAN) was created
by Robert Boush in mid-1980s as control units in
automobile industries. In the past, vehicle bus
communication uses point to point wiring systems;
which cause wiring to become more complex,
bulky, heavy and expensive with increasing
electronics and controllers deployed in a vehicle
 The WCAN protocol follows the concept of token
and the design of WCAN. It is proven that the use
of token concept has its advantages in terms of
improving efficiency by reducing the number of
retransmissions due to collisions which is more fair
as all stations use the channel for the same amount
of time.

4. What is WCAN – General Aspects
 Serial Network Technology for Embedded
Solutions Became very popular in Industrial
automation
 Network technology established among micro-
controllers Well suited for high speed/real-time
applications Replaces expensive Dual-Port RAM
technology.
 CAN chips manufactured by Motorola, Philips,
Intel, Infineon, ...
 600 Million CAN nodes used in 2007

5. What is CAN – Technical Aspects
 High-integrity serial data communications bus for
real- time applications
 Designed for max. performance &
reliability Operates at data rates up to 1
Mbit/sec
 Uses short messages – 8 bytes per message
 Excellent error detection and fault confinement
capabilities Is an international standard: ISO 11898

6. Protocol Features

7. Message Frames
 Three types of message frames:
 Data Frame – Broadcasts a message to the CAN bus:
 Error Frame - Requests transmission of message:
 Error Frame – Signals error condition
 Overload Frame –Special Error Frame

8. Message broadcasting with data frames
 Node A transmits a message
 Nodes B,C and D receive the message
 Nodes B and D accept the message, Node C declines

9. Message Request with Remote Frames 1
 Node A sends a remote frame (request)
 Node B, C, D receive message
 Node D accepts, Nodes B & C decline message

10. Message Request with Remote Frames 2
 Node D sends requested message
 Nodes A, B, C receive requested message
 Nodes A, B accept requested message, Node C declines

11. Standard CAN Protocol

12. Extended CAN Protocol
 Standard Format: 11 Bit Message Identifier
Extended Format: 29 Bit Message Identifier
 Both formats, Standard and Extended, may co-exist on the
same CAN Bus
 The distinction between both formats is managed by “Identifier
Extension Bit” (IDE)

13. Bus Arbitration Principle
 Bit wise arbitration across the Arbitration Field
 Dominant Bus Level = 0, Recessive Bus Level = 1
+

14. Dominant/Recessive Bus Level

15. Bus Arbitration Principle

16. WIRELESS CAN PROTOCOL
• Uses token frame in transmitting messages.
• Defines the ring network.
• Wireless based distributed MAC protocol for
ad-hoc network.
• WCAN Token Format:-

18. WCAN Operation
Ring Owner Of
Network
Data Frame Token
Other Nodes in idle mode till
it receives the circulated
token….(contd.)..

19. WCAN Operation
Process By
sending it to Upper
OSI
Receiving node
checks for
MsgID
Begins Arbitration &
removes frame and
token for fresh node
token entry

20. WCAN Timing
TRT = nx (Tm + DIFS) + Nx (Tt + DIFS)
TRT= Token Rotation Time
DIFS= Data Inter Frame Space
N= Total Nodes in Network
n= Active Nodes in processing of data frame

21. WCAN Timing (contd..)
S = (nxTm)xR/(nxTm + N(Tt + DIFS))
S= Aggregate throughput for a token ring
NOTE: Active Nodes may send one packet and one token in a
TRC(Token Rotation Cycle)

22. WCAN Performance Analysis
 Handling High Data Rate
 Increased Simulation by rate 50 ms/packet to
1 sec/packet
 Number Of Nodes :- 25
 Packet Size :- 512 bytes

23. WCAN Performance Analysis
 THROUGHPUT
 Outperforms IEEE 802.11 in all environment
 More the no. of packets higher the data rate.
 Highest is 81165 bps at 50 ms greater than traditional of
79395 bps at the same.
 Achievable Results is due to collision around 6.07% for
outperforming IEEE 802.11

24. WCAN Performance Analysis

25. WCAN Performance Analysis
 Packet Delivery Ratio
 Indication Of successful transmission of data
 WCAN outperforms IEEE 802.11 in te5rms of Delivery
Ratio
 Support of previous claim slightly
 IEEE 802.11 suffers collision of packet data
 Average 0.96 obtained on WCAN compared to that of
0.91 of IEEE 802.11

26. WCAN Performance Analysis

27. Error Detection
●  Error Frame
●
 Error Recovery Time = Error Flag + Error Delimiter +
Intermission Field = 12 + 8 + 3 = 23 Bits

28. Applications
 CAN is used wherever two or more microprocessor
units need to communicate with each other.
 Passenger Cars (multiple separate CAN networks)
 Trucks & Buses, Construction Vehicles,
Agricultural Vehicles (SAE J1939 protocol)
 Semiconductor Industry (Wafer Handlers, etc.)
 Robotics, Motion Control Application, Aircrafts (AC,
Seat Adjustment)
 Building Technologies (Light & Door Control
Systems, Sensors, etc.)
 Household Utilities (Coffee Machine, Washer, etc.)

29. CONCLUSION
Here I present my views on new wireless protocol namely wireless
controller area network (WCAN). WCAN uses the token frame
scheme as depicted in with some modification on the token format
and its operation. The developed WCAN is built on the MAC layer
as a wireless based distributed MAC protocol for ad-hoc network.
WCAN was deployed using QualNet simulator and achieve mixed
reaction results. Simulation results show that WCAN outperform
slightly in terms of throughput in a ring network environment and
increasing data packet rate. From the results of packet delivery
ratio, it is shown that WCAN provide ‘fair’ share for all nodes by
scheduling the transmission with token reception. This is proven
with the higher ratio value of WCAN.

30. References
 Controller Area Network, Basics
Protocols, Chips and Applications; Dr.
Konrad Etschberger; ISBN 3-00-
007376-0 (www.ixxat.com)
 CAN Systems Engineering, From
Theory to Practical Applications;
Wolfhard Lawrenz, ISBN 0-387-94939-
9
 http://en.wikipedia.org/wiki/CAN_bus

31. Thank You

32. Queries?