Protocol Design Using Finite State Machines Models

1
Protocol Design Using Finite State Machines
Models

• Fernando De Bernardinis, Marco Sgroi,
• Luciano Lavagno, Alberto Sangiovanni-Vincentelli

2
CFSMs Network
F
BgtC
CgtF
G
CgtG
CgtG
F(G1)
C
CgtA
CFSM2
CFSM2
CFSM1
CFSM1
C
CgtB
A
B
CgtB
(A0)gtB
CFSM3
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CFSMs

• CFSMs are FSMs extended with
• Support for data handling
• Asynchronous communication with unbounded delay
• GALS model
• Globally Asynchronous Locally Synchronous
• Communication between CFSMs
• Event-based
• Lossy (channels with one-place buffers)
• Events are overwritten if the sender is faster
  than the receiver

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Protocol Design Using CFSMs

• Limited lifetime of protocol entities
• Dynamic instantiation of CFSMs and communication
  channels
• Loss-less communication channels
• Extension of CFSMs with queues sizing problem.
• Explicit support for timers, mostly used at the
  physical layer
• Hierarchical CFSMs

5
Protocol Stack using CFSMs
Each layer is modeled as one or more CSFMs
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CoSimulation with a Radio model

• CFSM for Send()

Behavioral model of the radio (Proxim radio)

• Need
• StateFlow and Simulink Co-Simulation
• Polis/VCC - StateFlow Interface

7
Physical Layer Send() Example

• The service is activated by a send signal that
  carries the byte to be sent
• The CFSM takes care of the synchronization issue
• Timing information is provided by an external
  timer