The following figure illustrates the MSC for the communication between a
Transmitter/Verifier and a Receiver/Prover device as described before. This MSC includes
the handling of a successful data transfer with the packet transfer for communication
data and for the verifier/prover transfer. If the communication is successful, the SC is
updated, and the RC is set to zero. In addition, the failed transfer for the
communication transfer is illustrated in this figure. In this case, the receiver does
not receive the communication packet or the SSID address is wrong, or the reception
flags are wrong and, therefore, stay in the RX mode. The verifier sends the verifier
packet, but this results in a timeout because of no prover response. In this case, the
verifier switches back into the TX mode, keeps the actual SC value and increments the RC
value with the following AES encryption, MAC and RS code calculation before transmitting
the packet. The security data for the verifier and prover operation will not be changed
in this case.Figure 2-5. Message Sequence Chart for
Combined Data Communication and Ranging for a Successful Communication and for a
Lost Communication Packet Transfer
The other two failing communication scenarios are illustrated in the following figure. In
the case of a missing prover packet, the verifier device generates a timeout and is,
then, switched back into the TX mode. The SC value is kept as before, and the resend
counter is incremented before transmitting the encoded communication data frame. The
prover device switches back into the RX mode and receives the new communication packet,
recognizing the new RC and the previously failed communication to allow proper data
handling. The security data for the verifier and prover data will not be changed, and
the flow will, then, continue as described in the successful communication scenario. In
the case of wrong prover data received by the verifier, the MAC-1 information is
invalid. The handling of the sequence counter, the resend counter and the security data
will, then, be the same as for a lost prover packet (described before).Figure 2-6. Message Sequence Chart for
Combined Data Communication and Ranging for a Lost Prover Packet and for Wrong
Data in Prover Packet
An important topic for data transfer with the combination of communication and ranging
data packets is the link budget (LB). Due to the different lengths of the data packets
and the regulation limitations for the peak and average radiated TX power, the TX power
settings will be adjusted to keep the same LB for all packet transfers. If this is not
guaranteed, the BER and PLR both increase due to data bit errors and loss of data
packets. For more details on how to adjust the TX power levels, refer to the ATA8352
Impulse-Radio Ultra-Wideband (IR-UWB) Transceiver User’s Guide (DS50003125) and
for details on the regulation limitations, refer to the ATA5352 Testing and
Certifications Application Note (DS00004667).
The online versions of the documents are provided as a courtesy. Verify all content and data in the device’s PDF documentation found on the device product page.
