Itt Manufacturing Enterprises, Inc.

Richard S Orr

Gene L Cangiani

Boris Veytsman

Charles Q Nguyen

An intervote modulator () includes a majority voting logic unit () and an interplex modulator (). The majority voting logic unit receives plural signal codes (e.g., five codes x, x, x, x, x) together with their respective target gains G, G, G, G, Grepresenting the desired transmit power for the individual signal codes. The majority voting logic unit combines three of these five signal codes to form a majority vote composite signal while keeping the other two signal codes uncombined. The majority vote composite signal and the two uncombined signals are then supplied to the interplex modulator as signals s, sand s. The interplex modulator applies interplex modulation to signals s, sand sto form the in-phase and quadrature components of the final composite signal. The majority voting logic unit employs a generalized majority vote involving an interlace of sub-majority votes determined on a chip-by-chip basis.

Methods and apparatus for generating a constant-envelope composite transmission signal

Systems and methods are described here for locating the position of a mobile terminal in a cellular communications system. A base station in the cellular communication system broadcasts a communication signal having embedded therein a navigation signal. The navigation signal uses a chirp technique in which the chirp signal includes two portions, an up-chirp portion and a down-chirp portion. Each portion of the chirp signal is synchronized with a frame in the communication signal. The chirp navigation signal is at a power level much lower than the communication signal so as not to interfere with the communication signal. A mobile terminal generates a corresponding chirp signal to correlate with the incoming signal and to extract the navigation signal. The mobile terminal uses the detected navigation signal to determine a time of arrival of the communication signal for use in determining the position of the mobile terminal either at the terminal or to send to a network center for location processing.

Embedded chirp signal for position determination in cellular communication systems

CDMA codes are multiplexed into a constant-envelope composite signal using weighted majority logic. Based on a commanded power allocation among the signal codes, each signal code is assigned a weighting coefficient dictating the voting power the signal code has each time a vote is conducted, in a manner analogous to corporate shareholder voting. To multiplex the signal codes, a majority vote is conducted each chip period by summing the weighted chip values of the signal codes and assigning a binary value to the majority-voted composite chip based on the sign of the sum. An RF carrier is modulated in accordance with the value of the composite chip. The desired power distribution is achieved by requiring the power ratio of each signal code to be proportional to the square of the expected value of the cross-correlation between the signal code and a stored replica of the signal code at the receiver.

Methods and apparatus for multiplexing signal codes via weighted majority logic

A multiplexer and a method for chip-synchronous code-division multiple access (CDMA) signals produces a constant envelope signal. The output signal of the multiplexer permits use of a saturating (Class C) high power amplifier (HPA) resulting in a net increase in effective transmitter power usage. This multiplexer applies to a variety of CDMA spread spectrum modulation formats and has many applications, such as the IS-95 forward link interface, and CDMA and CDMA/FDMA (frequency-division multiple access) applications, including general cellular base station forward traffic channels, cellular subscriber station multiple-channel reverse traffic channels (e.g. IS-95 subscriber Internet access) and satellite downlinks.

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Montgomery Village, MD, United States of America

Richard S Orr