Wireless communication device and method for identifying the type of modulation among a plurality of modulation types in a near filed communication device
A method for configuring a first near-field communication device according to a modulation type transmitted by a second device, wherein: a decoder of the first device is configured to decode an overcoded type-B modulation; a signal received during a first time slot corresponding to the duration of a symbol of an initialization frame is decoded; and the first device is configured according to the value of the decoded symbol to determine the modulation type.
1. A device, comprising:
demodulation and decoding circuitry, which in operation, decodes received signals according to a selected modulation type of a plurality of modulation types; and
modulation-type selection circuitry, coupled to the demodulation and decoding circuity, wherein the modulation-type selection circuitry, in operation,
controls the demodulation and decoding circuitry to decode a received signal as a type-B modulated signal for a first time slot; and
when a result of the decoding of the first time slot as a type-B modulated signal is 00 in hexadecimal notation, the modulation-type selection circuitry:
controls the demodulation and decoding circuitry to decode the received signal as a type-B modulated signal for a second time slot:
when a result of the decoding of the received signal for the second time slot is 00 in hexadecimal notation, selects type-B modulation as the modulation type of the received signal; and
when a result of the decoding of the received signal for the second time slot is different from 00 in hexadecimal notation, selects type-15693-10 as the modulation type of the received signal.
2. The device of claim 1 wherein said time slot has a duration of 9.44 microseconds.
3. The device of claim 1 wherein when the result of decoding the first time slot is different from 00 in hexadecimal notation and smaller than AA in hexadecimal notation, the modulation-type selection circuitry selects type-15693-100 modulation as the modulation type of the received signal.
4. The device of claim 1 wherein when the result of decoding the first time slot is FC in hexadecimal notation, the modulation-type selection circuitry selects type-A modulation as the modulation type of the received signal.
5. The device of claim 1 wherein when the result of decoding the first time slot is AA in hexadecimal notation, the modulation-type selection circuitry selects type-C modulation as the modulation type of the received signal.
6. The device of claim 1 wherein when the result of decoding the first time slot is CC in hexadecimal notation, the modulation-type selection circuitry selects type-C modulation as the modulation type of the received signal.
7. The device of claim 1 wherein when the result of decoding the first time slot is not included in a set of results { 00 , FC, AA, CC} in hexadecimal notation, the modulation-type selection circuitry selects type-15693-100 modulation as the modulation type of the received signal.
8. The device of claim 7 wherein when the modulation-type selection circuitry selects type-15693-100 modulation as the modulation type of the received signal, the modulation-type selection circuitry determines whether the received signal is a type-15693-100-4 signal or a type-15693-100-256 signal.
9. The device of claim 1 wherein when the modulation-type selection circuitry selects type-15693-10 modulation as the modulation type of the received signal, the modulation-type selection circuitry determines whether the received signal is a type-15693-10-4 signal or a type-15693-10-256 signal.
10. A system, comprising:
analog-front-end circuitry; and
digital-signal-processing circuitry coupled to the analog-front-end circuitry, wherein the digital-signal-processing circuitry, in operation,
decodes a received signal as a type-B modulated signal for a first time slot; and
when a result of the decoding of the first time slot as a type-B modulated signal is 00 in hexadecimal notation:
decodes the received signal as a type-B modulated signal for a second time slot:
when a result of the decoding of the received signal for the second time slot is 00 in hexadecimal notation, selects type-B modulation as the modulation type of the received signal; and
when a result of the decoding of the received signal for the second time slot is different from 00 in hexadecimal notation, selects type-15693-10 as the modulation type of the received signal.
11. The system of claim 10 wherein said time slot has a duration of 9.44 microseconds.
12. The system of claim 10 wherein when the result of decoding the first time slot is different from 00 and smaller than AA, the digital-signal-processing circuitry selects type-15693-100 modulation as the modulation type of the received signal.
13. The system of claim 10 wherein when the result of decoding the first time slot is FC in hexadecimal notation, the digital-signal-processing circuitry selects type-A modulation as the modulation type of the received signal.
14. The system of claim 10 wherein when the result of decoding the first time slot is AA in hexadecimal notation, the digital-signal-processing circuitry selects type-C modulation as the modulation type of the received signal.
15. The system of claim 10 wherein when the result of decoding the first time slot is CC in hexadecimal notation, the digital-signal-processing circuitry selects type-C modulation as the modulation type of the received signal.
16. The system of claim 10 wherein when the result of decoding the first time slot is not included in a set of results {00, FC, AA, CC} in hexadecimal notation, the digital-signal-processing circuitry selects type-15693-100 modulation as the modulation type of the received signal.
17. A method comprising:
selecting a modulation type of a received signal by:
decoding the received signal as a type-B modulated signal for a first time slot; and
when a result of the decoding of the first time slot as a type-B modulated signal is 00 in hexadecimal notation:
decoding the received signal as a type-B modulated signal for a second time slot:
when a result of the decoding of the received signal for the second time slot is 00 in hexadecimal notation, selecting type-B modulation as the modulation type of the received signal; and
when a result of the decoding of the received signal for the second time slot is different from 00 in hexadecimal notation, selecting type-15693-10 as the modulation type of the received signal; and
decoding the received signal using the selected modulation type.
18. The method of claim 17 , comprising:
when the result of decoding the first time slot, in hexadecimal notation, is different from 00 and smaller than AA, selecting type-15693-100 modulation as the modulation type of the received signal.
19. The method of claim 17 , comprising:
when the result of decoding the first time slot is FC in hexadecimal notation, selecting type-A modulation as the modulation type of the received signal.
20. The method of claim 17 , comprising:
when the result of decoding the first time slot is AA in hexadecimal notation, selecting type-C modulation as the modulation type of the received signal.
21. The method of claim 17 , comprising:
when the result of decoding the first time slot is CC in hexadecimal notation, selecting type-C modulation as the modulation type of the received signal.
22. The method of claim 17 , comprising:
when the result of decoding the first time slot is not included in a set of results {00, FC, AA, CC} in hexadecimal notation, selecting type-15693-100 modulation as the modulation type of the received signal.