RFID readers transmitting preambles denoting data rate and methods
First Claim
1. An RFID reader capable of at least:
- transmitting a preamble that includes a call aspect implemented by call transitions that define a timing whose duration is independent of a preset data rate, and a rate aspect having a feature substantially determined from the data rate; and
then transmitting data at the data rate.
1 Assignment
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Accused Products
Abstract
RFID readers transmit data to query tags at one or more data rates. Before transmitting data, the RFID readers also transmit special preambles that inform of the data rate that will be used for transmitting the data. The preambles have a call aspect and a rate aspect. The rate aspect has a feature substantially determined from a rate selected for transmitting the data. The feature may encode the rate indirectly or explicitly. The call aspect may be implemented by call transitions that define a timing, whose duration is independent of the selected rate. The duration may be advantageously set according to an assumed state of the RFID tag bandwidth filter. Therefore an RFID tag may use the call aspect of the preamble to prepare itself for receiving data, and the rate aspect to determine its rate of transmission for setting its filter bandwidth accordingly.
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Citations
95 Claims
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1. An RFID reader capable of at least:
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transmitting a preamble that includes a call aspect implemented by call transitions that define a timing whose duration is independent of a preset data rate, and a rate aspect having a feature substantially determined from the data rate; and
then transmitting data at the data rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An RFID reader comprising:
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means for transmitting a preamble that includes a call aspect implemented by call transitions that define a timing whose duration is independent of a preset data rate, and a rate aspect having a feature substantially determined from the rate; and
means for transmitting data at the rate. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method for an RFID reader to transmit data at a data rate, comprising:
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transmitting a preamble that includes a call aspect implemented by call transitions that define a timing whose duration is independent of the data rate, and a rate aspect having a feature substantially determined from the data rate; and
then transmitting data at the data rate. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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51. An RFID reader capable of transmitting:
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first data, and a first preamble to the first data, the first preamble including at least two low pulses of different durations. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72)
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73. An RFID reader for transmitting to an RFID tag, comprising:
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means for selecting one of a first rate and a second rate;
means for transmitting a first preamble to first data that includes at least two low pulses of different durations; and
means for transmitting the first data at the selected rate. - View Dependent Claims (74, 75, 76, 77, 78, 79, 80, 81)
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82. A method for an RFID reader to transmit to an RFID tag, comprising:
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transmitting a first preamble to first data that includes at least two low pulses of different durations; and
transmitting the first data. - View Dependent Claims (83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95)
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Specification