Andrew E Macdonald, 3631 Governor St, Providence, RI 02906

5504453, Apr 2, 1996

Oct 14, 1994

8/323283

Andrew MacDonald - Damascus MD
Richard Clewer - Ijamsville MD

Hughes Aircraft Company - Los Angeles CA

H04L 2722

329304

A method and apparatus for use in estimating phase error in a phase-modulated carrier. The method and apparatus of the present invention may be embodied in a phase-error-estimator circuit which is typically incorporated into a demodulator of a digital communications receiver. In general, the phase-error-estimator circuit receives the I and Q components of a phase-modulated signal, and outputs an estimate of the phase error, if any, in the phase-modulated carrier signal associated with the received I and Q. Preferably, the phase-error-estimator circuit includes an index/polarity generator circuit coupled to a look-up table. The index/polarity generator receives I and Q and maps them onto a reduced range of phase angles represented by values X and Y. X and Y are fed to a reduced and substantially triangular look-up table which outputs the stored phase-error-estimate for the particular X and Y inputs.

5606569, Feb 25, 1997

Feb 15, 1996

8/601890

Andrew J. MacDonald - Damascus MD
Stanley E. Kay - Rockville MD

Hughes Electronics - Los Angeles CA

H03M 1300
H03M 1312

371 377

A cellular base station receiver uses a digital signal processor to decode receiver code words in an inner Reed-Solomon code. A list of code word estimates is generated by making different symbol erasure combinations. An outer cyclic redundancy code operates as an error detector for the word estimates. When a code word estimate is found to be error-free, it is accepted for output.

5365571, Nov 15, 1994

May 24, 1993

8/064997

Peter S. Rha - Chevy Chase MD
Stanley E. Kay - Rockville MD
Andrew J. MacDonald - Damascus MD

Hughes Aircraft Company - Los Angeles CA

H04M 1100
H04Q 700

379 59

A cellular radio-telephone system has a plurality of cells each of which has S sectors. The cells are grouped into a plurality of clusters each of which has N adjoining cells. Each cell has a set of assigned system frequencies with respective frequency subsets assigned to its sectors so that N groups of co-channel cells exist with each co-channel cell group including one cell from each cluster having channel frequencies corresponding to those for its co-channel cell group. Respective base station antennas are located in the respective sectors of the respective cells, and each of the cell sectors has a plurality of subscriber station directional antennas disposed at predetermined locations within the sector for communication linkage with the associated base station antenna. The cells are generally formed in rows and columns and further are formed to provide a predetermined relative orientation pattern for co-channel cell sectors. Co-channel cells form a first cell tier around a preselected center co-channel cell with a common direction operative as a reference orientation direction for co-channel sectors therein.

6031474, Feb 29, 2000

Mar 10, 1998

9/038367

Stanley E. Kay - Rockville MD
Yezdi Antia - Gaithersburg MD
Andrew J. Macdonald - Damascus MD

H03M 700

341106

A novel code and method of code construction is disclosed. The disclosed code is a half rate block code designed to function optimally in a Raleigh fading channel. The disclosed code and method may be implemented in an 8-ARY QPSK modulation system. An alternative embodiment is a code and method of code construction for use in a 16-ARY QPSK modulation system. Both codes are systematic and use four symbols to represent two symbols. The first two symbols of the code are the information symbols. The second two symbols are parity symbols. The parity symbols are selected to provide maximum Euclidean distance between code words.

5390197, Feb 14, 1995

Dec 4, 1992

7/985767

Andrew J. MacDonald - Damascus MD
Youngky Kim - N. Potomac MD
Stanley E. Kay - Rockville MD

Hughes Aircraft Company - Los Angeles CA

G06F 1110

371 371

A vestigial identification system is provided for transmitting information in a cellular communications network employing frequency reuse. The vestigial identification system enables a receiver to detect both bit errors and interfering messages to avoid call disruption. A composite parity check is produced by encoding message data and a site identifier via an encoder. A transmitter conveys a code word, formed at a code word generator by combining the composite parity check with the message data, to a receiver. At the receiver, an encoder forms an error detection parity check by encoding both the message data from the code word and the site identifier. An error detector compares the composite parity check from the transmitted code word to the error detection parity check, and generates an error if the parity checks are not identical to one another, enabling rejection of the message by the receiver.

2014017, Jun 19, 2014

Dec 13, 2013

14/105698

Ian Dobson - London, GB
John Doyle - Southborough MA, US
Charles Isaac - Carlsbad IL, US
Andrew MacDonald - Lafayette LA, US
Katherine Smart - Rempstone, GB

C12P 7/10

435165

A method of producing renewable material comprising (a) converting biologically a hemicellulose-derived material to form a first mixture comprising a first renewable material, and (b) convening a substantial amount of a material comprising cellulose and lignin in the presence of at least a portion of the first mixture to form a second mixture comprising second renewable material.