Radio based collision detection for wireless communication system
First Claim
1. An apparatus for a station on a wireless communication channel, which detects collisions between data transmissions in the wireless communication channel, comprising:
- a detector which detects mixing products of colliding data transmissions at the station; and
signal processing resources, coupled to the detector, which indicate collisions between data transmissions based upon characteristics of the mixing products, wherein the data transmissions comprise a frequency modulated carrier having a center frequency, a low frequency below the center frequency representing a first data value, and a high frequency above the center frequency representing a second data value, and the signal processing resources are responsive to a mixing product based on a difference between the low frequency and the high frequency.
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Accused Products
Abstract
A collision detection method and apparatus which is suitable for use in a wireless CSMA/CD network, or other wireless networks where collision detection is provided. The apparatus includes a detector which detects intermodulation or other mixing products of colliding data transmissions at a station in the network, and a signal processor which indicates collisions between the data transmissions based upon characteristics of the intermodulation products. The system is capable of detecting collisions, both between transmissions from the station on which the device is located and transmissions from other sources, and between two transmissions being received from other sources. The station includes a transmitter having an input for a data packet. Resources coupled to the input add a header to the data packet, the header having characteristics monitored by the collision detector circuitry including a pseudo-random bit sequence. Data transmission signals are supplied to the transmitter in response to the header and the data packet. Thus, collisions occurring during transmission of the header sequence have intervals during which a mismatch occurs between the colliding signal and the data transmission.
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Citations
36 Claims
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1. An apparatus for a station on a wireless communication channel, which detects collisions between data transmissions in the wireless communication channel, comprising:
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a detector which detects mixing products of colliding data transmissions at the station; and signal processing resources, coupled to the detector, which indicate collisions between data transmissions based upon characteristics of the mixing products, wherein the data transmissions comprise a frequency modulated carrier having a center frequency, a low frequency below the center frequency representing a first data value, and a high frequency above the center frequency representing a second data value, and the signal processing resources are responsive to a mixing product based on a difference between the low frequency and the high frequency.
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2. An apparatus for a station on a wireless communication channel, which detects collisions between data transmissions in the wireless communication channel, comprising:
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a detector which detects mixing products of colliding data transmissions at the station; and signal processing resources, coupled to the detector, which indicate collisions between data transmissions based upon characteristics of the mixing products, wherein the station includes a transmitter, the transmitter including an amplifier having a nonlinear response to colliding signals which produces intermodulation products, and the detector comprises; a filter coupled to the transmitter which passes an intermodulation product characteristic of colliding data transmissions to the signal processing resources. - View Dependent Claims (3, 4)
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5. An apparatus for a station on a wireless communication channel, which detects collisions between data transmissions in the wireless communication channel, comprising:
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a detector which detects mixing products of colliding data transmissions at the station; and signal processing resources, coupled to the detector, which indicate collisions between data transmissions based upon characteristics of the mixing products, wherein the station comprises a receiver, and the detector comprises a nonlinear device coupled to the receiver which produces intermodulation products, and a filter coupled to the nonlinear device which passes an intermodulation product characteristic of colliding data transmissions to the signal processing resources. - View Dependent Claims (6, 7)
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8. A station for a wireless link in a network, comprising:
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a transmitter to supply a data transmission from the station; a transmit collision detector, coupled to the transmitter, which detects collisions between the data transmission from the station and data transmissions from other sources received during the transmission; a receiver to receive data transmissions from other sources; a receive collision detector, coupled to the receiver, which detects collisions between data transmissions at the station from other sources. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A station for a wireless link in a network, comprising:
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a transmitter, including an amplifier coupled to supply a data transmission in response to a data transmission signal; an input which receives a digital data packet for transmission; resources which apply a header to the digital data packet; frequency modulation circuitry coupled to the input which supplies a data transmission signal to the amplifier which comprises a carrier frequency modulated in response to the header and the digital data packet; a transmit collision detector, coupled to the transmitter, which detects mixing products of the data transmission from the amplifier and signals from other sources received during the transmission; a receiver; signal processing resources, coupled to the transmit collision detector, which indicate collisions between data transmissions based upon characteristics of the mixing products. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for detecting collisions in a station on a wireless link of a network operating a carrier sense multiple access with collision detection (CSMA/CD) protocol, comprising:
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applying a header to data packets to be transmitted on the wireless link which includes a collision detect sequence for the station including collision detect symbols having a duration longer than a characteristic settling time for the wireless link; producing mixing products in the station between the collision detect sequence in data transmissions by the station and signals from other sources; and processing the mixing products to detect collisions between data transmissions. - View Dependent Claims (28, 29)
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30. A method for detecting collisions in a station on a wireless link of a network operating a carrier sense multiple access with collision detection (CSMA/CD) protocol, comprising:
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applying a header to data packets to be transmitted on the wireless link; producing mixing products in the station between data transmissions by the station and signals from other sources; and processing the mixing products to detect collisions between data transmissions, wherein the header comprises a sequence of symbols assigned to the station intended to be different than sequences assigned to other stations in the wireless link, so that collisions occurring during transmission of the sequence have intervals during which a mismatch occurs between the colliding signal and the data transmission. - View Dependent Claims (31, 32, 33, 34)
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35. A method for detecting collisions in a station on a wireless link of a network operating a carrier sense multiple access with collision detection (CSMA/CD) protocol, comprising:
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applying a header to data packets to be transmitted on the wireless; producing mixing products in the station between the header in data packets transmitted by the station and signals from other sources; and processing the mixing products to detect collisions between data transmissions, wherein the data transmission comprises a carrier having a nominal center frequency, a low frequency below the nominal center frequency representing a first data value, and a high frequency above the nominal center frequency representing a second data value, and the mixing product produced is based on a difference between the low frequency and the high frequency. - View Dependent Claims (36)
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Specification