Motorola Corporation

Motorla, Inc.

David E Borth

Phillip D Rasky

Kevin Lynn Baum

Ira A Gerson

Richard J Vilmur

James F Kepler

Bruce D Mueller

John R Haug

Gerald P Labedz

Fuyun Ling

Duane C Rabe

Eric H Winter

James Joseph Mikulski

Chih-Fei Wang

Colin D Frank

M Vedat Eyuboglu

Eric R Schorman

Walter J Rozanski, Jr

Brett L Lindsley

Kevin L Kloker

Charles N Lynk

William V Braun

John E Major

Frank J Cerny, Jr

Gregory M Chiasson

John S Csapo

Morton Stern

Philip J Smanski

John W Arens

A system and method for calculating survivor metrics in a Viterbi equalizer of a receiver, such as a receiver operative to receive a PSK-modulated signal, for example, a .pi./4, differential, phase-shift-keying, modulated signal. The state transition metric, defined as a function of two successive states, is converted into a function defined by pairwise differences between allowable symbols of a PSK-modulated signal. When operative to receive the .pi./4 DQPSK-modulated signal, the number of calculations required to calculate state transition metrics is reduced significantly.

System and method for calculating a state transition metric in a viterbi

A system (200) and method (300) provide an efficient communication system for distributing digital multimedia/HDTV signals to multimedia units in a cellular pattern. The method includes: 1) using at least a first primary wide area-antenna for, where selected, transmitting a digital multimedia/HDTV signal per frequency allocation over at least a portion of a predetermined reception area, wherein a plurality of patterns of cells tesselates the predetermined reception area; and 2) using cell-site antennas having transmitters, each located in a cell, for, where selected, transmitting, when the primary wide area-antenna is deselected, at least a first preselected digital multimedia/HDTV signal over an area of the cell, for providing the HDTV signal to a plurality of digital receivers in accordance with a predetermined scheme, wherein the digital multimedia/HDTV signal is associated with a predetermined frequency allocation.

Method and system for distribution of wireless digital multimedia

A receiver circuit (400, 500) receives a spread spectrum communication signal, such as a DS-CDMA signal, including a pilot channel and including a power control designator. The signal is despread and decoded. The pilot symbols on the pilot channel are provided to a channel estimator (408) for estimating the channel phase and channel gain of the communication channel. This estimate is provided to a demodulator (422) for demodulating the traffic channel symbols. The pilot symbols are provided to another channel estimator (410) for estimating channel phase and channel gain for the power control designator. This estimate is provided to a demodulator (424) for demodulating the power control designator. The traffic channel symbols are delayed a predetermined time in a delay element (420) before demodulating. The power control designator is delayed a short time or not at all in a short delay element (418) before demodulation.

Method and apparatus for demodulation and power control bit detection in

The dual mode communication network comprises a first communication system having a frame structure and a first traffic channel protocol and a second communication system having the frame structure and a second traffic channel protocol. In the network, only one of the first and second traffic channel protocols supports forward error correction coding.

Dual mode communication network

Registration operates by sensing (106) the availability of a first communication system. A quality factor of a channel of the system is measured (111). A channel of the first system is selected if the quality factor of the channel exceeds a threshold (113). If selected, the subscriber attempts to register the call (114). If the registration fails, the availability of a second communication system is sensed (107). A quality factor of a channel of the second system is measured (111) and selected (113), if the quality factor exceeds a threshold. The subscriber will then attempt to register (114) with the second system. Reassignment operates by determining if the first system has reached a capacity limit (126). If it has, it determines if a channel on the second system is available (128). If available, a transfer of the call from the first to the second system will be attempted (132).

Method of registering/-reassigning a call in a dual mode communication

A dual mode radio communication unit for a digital communication system is provided having an error controller including an error detection encoder and a forward error correction encoder which encode an input information signal into an error protected data bit stream. In addition, the communication unit includes a mode selector which enables either the error detection encoder or the forward error correction encoder used with a particular mode of operation of the communication unit. Further, a corresponding dual mode radio communication unit is provided having an error controller for generating estimated information signal samples according to a group of algorithms consisting of either an error detection algorithm or an error correction algorithm. In addition, the corresponding communication unit includes a mode selector for receiving a signal according to a particular one of the group of algorithms which is associated with a particular mode of operation of the corresponding communication unit.

Dual mode radio communication unit

A cellular communication system hops both signalling channels and traffics channels in a common hopping sequence. To obtain system information from the frequency hopping signalling channel, a subscriber unit waits on a predetermined frequency, or carrier, until the frequency hopped signalling channel arrives at the predetermined frequency. Once arrived, the subscriber unit obtains synchronization information, and information related to the hopping sequence, from the signalling channel during the hop. The subscriber unit may then hop in tandem with the system, obtaining further system information in subsequent hops. The cellular communication system supports mobile assisted handoff (MAHO) by allowing a subscriber unit to measure signalling channel of neighboring cells in a similar manner, and using the measurements to assist in communication handoff from a source cell to a neighboring cell.

Method and apparatus for frequency hopping a signalling channel in a

A system and method for correcting for Rayleigh interference of a signal transmitted upon a multi-path channel. The system adaptively calculates values of channel gain and noise variance of the channel upon which the signal is transmitted, and generates signals indicative of such calculations which are supplied to a decoder. The system may be utilized to form a portion of a coherent, or noncoherent receiver which receives encoded and differentially-encoded signals.

System and method for calculating channel gain and noise variance of a

There is provided a mechanism for Automatic Gain Control in a receiver. It comprises: determining, within a certain dynamic range, the difference in power between the desired signal and a signal received, and providing open loop gain control for the signal in response to the differential so determined, scaled by the receiver's gain characteristics, such that the signal is positioned within dynamic range so as to reduce saturation and noise.

Method and apparatus for digital automatic gain control in a receiver

There is provided a method of digital Automatic Gain Control (AGC) in a receiver having limited dynamic range, particularly for discontinuous signals. The method comprises detecting the level of a received and AGC'd discontinuous signal, comparing the level of the AGC'd signal relative to the dynamic range of the receiver, and adjusting the AGC to establish a desired relationship between the AGC'd signal and the dynamic range limitation. There is also provided a method of handoff in a TDMA cellular-type transmission system utilizing this method of AGControl. The method for Automatic Gain Control (AGC) of discontinuous signals in a receiver having limited dynamic range is further characterized by: digitizing a received and AGC'd discontinuous signal and converting the digitized samples to a power sample to sense the power of and detect the level of the signal, comparing the level of the AGC'd signal relative to the dynamic range of the receiver; and coarsely-adjusting by either progressively attenuating the signal until it falls within the dynamic range of the receiver or by progressively gain-amplifying the signal until it falls within the limited dynamic range of the receiver and finely-adjusting the AGC of the received signal until optimum use of the full (albeit limited) dynamic range of the signal processing stages is about 6-12 dB below maximum sensitivity to establish a desired relationship between the AGC'd signal and the dynamic range limitation.

Digital automatic gain control

A Viterbi equalizer for decoding a .pi./4 DQPSK modulated signal. Because symbol values of adjacent symbols of a .pi./4 DQPSK signal are offset in phase relative to one another, allowable values of succeeding states of a .pi./4 DQPSK signal are four in number. The signal paths of the Viterbi equalizer are thereby limited in number to four allowable next-states, and the Viterbi equalizer is operative to select certain ones of the paths connecting the states at the adjacent time intervals as survivor paths to form maximum likelihood paths thereby.

Viterbi equalizer for radio receiver

A communications system receiver (100) is disclosed which receives a transmitted signal over a radio channel. The transmitted signal includes data and a predetermined synchronization sequence. The receiver (100) includes a demodulator (215), and a stored replica (207) of the predetermined synchronization sequence. The receiver (100) further includes apparatus (102) for computing (308) a reconstructed signal, by using the channel impulse response characteristic and the stored replica (207) of the synchronization sequence. A feature of the invention is to estimate (310) a phase offset value between an incoming signal and the reconstructed signal, for a plurality of synchronization symbols. This serves to establish (315) a relationship between the phase offset and a synchronization symbol index. The receiver then employs this relationship to derive (317) at least one 'previous' phase state (214) for initializing (314) the demodulator (215).

Communication system receiver apparatus and method for fast carrier

There is provided a mechanism for soft trellis decoding. It comprises: generating decisions that rely upon other decision making and associating with it information indicative of the confidence held in those decisions and generated from the relative merit of any given decision. It further comprises: generating Maximum Likelihood Sequence Estimation equalization decisions and multiplying a signed value of the generated decision by the absolute values of the difference between alternative criterion utilized to arrive at any given decision, whereby the relative merit comprises a measure of signal quality at the time that given decision is made.

Soft trellis decoding

A signal weighting system for associating a confidence level with portions of a communication signal transmitted upon a multipath channel and received by a receiver. A signal received by the receiver is equalized by an equalizer circuit, such as a maximum likelihood sequence estimator, and the equalized signal generated thereby is supplied to an adaptive filter which is synthesizes portions of the multipath channel. The signal received by the receiver is altered responsive to values of a filtered, equalized signal generated by the adaptive filter.

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Palatine, IL, United States of America

David E Borth