Hughes Aircraft Company

3com Corporation

Allen Podell

Lawrence M Burns

David A Fisher

Ravi Ramachandran

Jon J Gulick

Kathleen L Virga

Curtis L Hanz

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.

Radio based collision detection for wireless communication system

A microstrip transmission line structure a series of connected microstrip strip sections having different widths disposed on an outside layer of a unitized multilayer circuit structure and forming a microstrip line, respective ground planes for each of the strip sections formed between insulating layers of the untilized multilayer circuit structure and respectively spaced from the associated strip sections to provide a substantially constant impedance along the length of the microstrip line, and a plurality of conductive vias for electrically interconnecting the respective ground planes.

Constant impedance transition between transmission structures of

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Palo Alto, CA, United States of America

Allen Podell