05999561 is referenced by 274 patents and cites 22 patents.

A method, apparatus, computer-based product and system employs a digital receiver (or transceiver) to receive, digitize and process a direct sequence spread spectrum signal using efficient, low-cost digital signal processing components. A radio front end portion of the receiver receives and digitizes the signal, and a digital signal processing portion downconverts and despreads the signal by applying a pseudorandom noise (PN) code, used at a transmitter to spread a data signal contained in the direct sequence spread spectrum signal, to the received signal. In order to initially align, and maintain alignment of, the PN code with the direct sequence spread spectrum signal, a timing and state control mechanism is included that provides time reference correction information to the signal processing components of the receiver. This time reference correction information allows the receiver to be compatible with transmitters using inaccurate frequency references which impart a significant frequency ambiguity in the received signal. Additional features include computer-based synchronization methods and mechanisms suitable for use for low performance digital signal processors and employ power management mechanisms that enable long-term operation using battery power. The power management mechanisms enable the receiver to operate in a network setting, over the course of multiple years off battery power, with similar receivers, transmitters and transceiver that communicate with one another using direct sequence spread spectrum signals.

Title
Direct sequence spread spectrum method, computer-based product, apparatus and system tolerant to frequency reference offset
Application Number
8/929891
Publication Number
5999561
Application Date
September 15, 1997
Publication Date
December 7, 1999
Inventor
Marc L Reed
Mandeville
LA, US
Charles A Hwang
New Orleans
LA, US
Dale E Reiser
New Orleans
LA, US
H Britton Sanderford Jr
New Orleans
LA, US
Robert E Rouquette
Kenner
LA, US
Gary A Naden
Mandeville
LA, US
Agent
Oblon Spivak McClelland Maier & Neustadt P C
Assignee
Sanconix
LA, US
IPC
H04B 1/707
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