Motorola Corporation

Joseph J Schuler

Michael D Kotzin

Gerald P Labedz

Duane C Rabe

John M Smith

Frederick G Atkinson

Alton P Werronen

Richard I Little

Ole H Jenson

A communication system receives and codes a plurality of information signals according to coding assignments to produce a plurality of coded baseband signals. From these signals, a simulated composite carrier signal is formed which has all the characteristics of an actual composite carrier signal which would have resulted if the plurality of coded baseband signals had been formed. The simulated composite carrier signal is analyzed to determine its peak-to-average ratio. The communication system selects a different coding assignments for coding the plurality of information signals if, based on the determined peak-to-average ratio and a selection criteria, the coding assignment does not produce the desired results. The communication system selects a different coding assignments until at least one or several desired coding techniques have been identified, ranks the coding techniques and makes a final selection of the coding technique to meet the peak-to-average ratio requirements.

Method and apparatus for analyzing a composite carrier signal

A method and apparatus are provided for receiving electromagnetic radiation within a frequency band. The receiving is accomplished by intercepting electromagnetic radiation within the frequency band and converting the intercepted electromagnetic radiation into an electrical signal. Subsequently, a portion of the electrical signal is digitized into digitized signals. Each digitized signal represents the intercepted electromagnetic radiation within a portion of the frequency band. Finally, a composite digitized signal is generated from at least two of the digitized signals. Alternatively, the receiving process may be enhanced by intercepting first electromagnetic radiation within a portion of the frequency band and by intercepting second electromagnetic radiation within another portion of the frequency band. Subsequently, the first and the second electromagnetic radiation is combined into a composite electromagnetic radiation waveform. The composite electromagnetic radiation waveform is converted into an electrical signal which may be processed into digitized signals which form a composite digitized signal.

Method and apparatus for receiving electromagnetic radiation within a

A method and apparatus are provided for digitizing a wide frequency bandwidth signal (105). The digitizing is accomplished by separating the wide frequency bandwidth signal (105) into a plurality of narrow frequency bandwidth signals with a plurality of filters (110). Subsequently, a converter (120) generates digitized samples of the narrow frequency bandwidth signals. Finally, a composite digitized signal (160) is generated by a combiner (150) from the digitized samples which substantially represents the wide frequency bandwidth signal (105).

Method and apparatus for digitizing a wide frequency bandwidth signal

An equalization system for equalizing a corrupted signal is disclosed. The equalization system includes a complex matched filter (400) and a maximum likelihood sequence estimator (MLSE) (405) for removing the effects of phase shift, amplitude variations, intersymbol interference, etc. resulting from multi-pathing and noise contributed by the receiver front end. The system estimates a correlation signal C(t) (505) and synchronizes C(t) 505 to maximize its energy as seen on the taps of the complex matched filter (400). Taps having amplitude coefficients below a predetermined threshold are set to zero to produce a modified CIR estimate. The modified CIR estimate which has had the effects of noise virtually eliminated, is then used to construct the complex matched filter (400) and is also used as input to the MLSE (405) to produce a better equalized data signal.

Apparatus and method for equalizing a corrupted signal in a receiver

A method and appartus for diversity reception in a communication system wherein at least a dual branch receiver is provided with a stored replica of expected reference information that is correlated with the received time-dispersed signals to obtain an estimate of the transmission channel's impulse response as seen by each branch, and determine, among other things, phase error between the branch local oscillators and the time-dispersed signals. Matched filters are constructed which then coherently align the time-dispersed signals from each branch with that branch's local oscillator, also constituting the first part of the equalization. The diversity processing stage may perform bit by bit selection on the re-aligned signals, maximal ratio combining of the re-aligned signals, or equal gain combining of the re-aligned signals, following each by a sequence estimation which uses similarly selected or combined channel distortion compensation parameters to complete the equalization process on the new signal. In digital modulated carrier systems, providing expected reference information eliminates the neeed for carrier recovery feedback for each branch while performing part of the equalization process.

Method and apparatus for diversity reception of time-dispersed signals

An antenna switching system for handling high traffic sectors in a cellular radiotelephone system. The system switches the cell's base station transmitters to sectors that have more mobile traffic than they can handle. The additional transmitters increase the number of frequencies in the overloaded sector, thereby allowing a greater amount of mobile traffic to use the cell.

Antenna switching system

A power amplifier is provided for amplifying a radio frequency signal such as in a burst modulation manner for use in GSM cellular radio. The amplifier has means, such as a ROM (16), for producing a predetermined sequence of values in response to a control pulse. Means (21) are provided for converting each value into a power control signal, and control means (9) are provided for controlling the amplifier output power in accordance with said power control signal. In this manner, the power/time characteristic can be made to take the form of a raised cosine. The invention also provides power selection means for selecting a nominal output level from a plurality of discrete levels and for selecting power sub-levels offset from said selected level. An indication is recorded as to which sub-level best represents the nominal power level.

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Roselle, IL, United States of America

Joseph J Schuler