During a scenario, when a tag is not participating in a transaction, the tag remains in the
sleep state, S1. After receiving a wake-up tone, it proceeds to state S2 and listens for the
preamble signal. The transition from S2 to S3 occurs when a tag receives a valid preamble
and is ready to receive the incoming command. After receiving the command, the tag
decides whether to continue processing the command (e.g., move to state S4) or return to
the listen for the preamble state (move to state S2). If the incoming command is intended
TABLE 11.7
ASIC versus FPGA Power Consumption for Portions
of the Smart Buffer
Component Spartan 3 0.16 mm ASIC
Wake-up signal 0.01 mW 0.001 mW
Preamble detection 0.87 mW 0.005 mW
Manchester decoder 0.95 mW 0.284 mW
Quiescent power 92 mW 0 mW
Total 93.83 mW 0.29 mW
Minimum Energy=Power Considerations 225
for the tag, it will process the command in state S4 and transmit the associated information
back to the reader in state S5. Otherwise, the tag will drop the command and move from S3
to S2. If the command received is to put the tag to sleep it transitions to the sleep state, S1.
CMD
receiving
S3 Transmission
S5
Preamble
listening
S2
Sleep
S1
CMD
processing
S4
?µP (S) ?µP (A)
?µP (A)
?µP (A)
?µP(A)
p11
p12
p23
p32
p34
p44
p33
p31
p52
p45 p55
FIGURE 11.27
Markov process model for an RFID tag with an on-tag microprocessor (MP-mP model).
Pages:
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438