Ground based beam forming utilizing synchronized code division multiplexing
First Claim
Patent Images
1. A method of beam forming at a ground station used in a satellite system employing multiple information carrying transmission links, comprising the steps of:
- spreading each of said transmission links using an orthogonal spreading code, each of said links occupying substantially the same frequency band over the same time interval;
combining said spread links into an uplink feeder signal and transmitting same to a satellite;
receiving a downlink feeder signal from the satellite;
separating the downlink feeder signal into a plurality of transmission links; and
removing the orthogonal spreading code from the plurality of transmission links so as to permit retrieving any information carried by the transmission links.
2 Assignments
0 Petitions
Accused Products
Abstract
A method permitting beam forming at a ground station for providing a coherent and stable uplink signal to a satellite system employing multiple spot beams by combining orthogonal synchronous code division multiplex codes and pseudo-random spreading codes with an information signal to implement a satellite feeder uplink.
-
Citations
18 Claims
-
1. A method of beam forming at a ground station used in a satellite system employing multiple information carrying transmission links, comprising the steps of:
-
spreading each of said transmission links using an orthogonal spreading code, each of said links occupying substantially the same frequency band over the same time interval; combining said spread links into an uplink feeder signal and transmitting same to a satellite; receiving a downlink feeder signal from the satellite; separating the downlink feeder signal into a plurality of transmission links; and removing the orthogonal spreading code from the plurality of transmission links so as to permit retrieving any information carried by the transmission links.
-
-
2. A method of beam forming at a ground station used in a satellite system employing multiple information carrying transmission links, comprising the steps of:
-
spreading each of said transmission links using an orthogonal spreading code by encoding separate transmission links with a unique orthogonal Code Division Multiplex (CDM) code; combining said spread links into an uplink feeder signal and transmitting same to a satellite; receiving a downlink feeder signal from the satellite; separating the downlink feeder signal into a plurality of transmission links; and removing the orthogonal spreading code from the plurality of transmission links to permit retrieving any information carried by the transmission links. - View Dependent Claims (3)
-
-
4. A method of beam forming at a ground station used in a satellite system employing multiple information carrying transmission links, comprising the steps of:
-
spreading each of said transmission links using an orthogonal spreading code; combining said spread links into an uplink feeder signal and transmitting same to a satellite; receiving a downlink feeder signal from the satellite; separating the downlink feeder signal into a plurality of transmission links; removing the orthogonal spreading code from the plurality of transmission links to permit retrieving any information carried by the transmission links; and converting the uplink feeder signal from a digital signal to an analog signal prior to transmission. - View Dependent Claims (5)
-
-
6. A method of beam forming at a ground station used in a satellite system employing multiple information carrying transmission links, comprising the steps of:
-
spreading each of said transmission links using an orthogonal spreading code; combining said spread links into an uplink feeder signal and transmitting same to a satellite; receiving a downlink feeder signal from the satellite; separating the downlink feeder signal into a plurality of transmission links; removing the orthogonal spreading code from the plurality of transmission links to permit retrieving any information carried by the transmission links; and selecting the orthogonal spreading codes from a Walsh type Hadamard code arranged in an approximate order of increasing frequency content. - View Dependent Claims (7)
-
-
8. A method of beam forming at a ground station used in a satellite system employing multiple information carrying transmission links, comprising the steps of:
-
spreading each of said transmission links using an orthogonal spreading code; combining said spread links into an uplink feeder signal and transmitting same to a satellite; receiving a downlink feeder signal from the satellite; separating the downlink feeder signal into a plurality of transmission links; removing the orthogonal spreading code from the plurality of transmission links to permit retrieving any information carried by the transmission links; and synchronizing the satellite system with the feeder signals by simultaneously transmitting at least one pseudo-random synchronization code with the uplink signal. - View Dependent Claims (9, 10)
-
-
11. A ground based beam former for use with a satellite system, comprising:
-
a complex Analog-to-Digital Converter (ADC) for receiving a channelized signal input and providing a plurality of complex sample outputs, Zn ; the plurality of complex sample outputs Zn thereafter coupled through a forward link for providing a plurality of premutated orthogonal CDM signal outputs; and the CDM signal outputs coupled through a summing network and a Digital-to-Analog Converter (DAC) into an uplink transmitter for transmission to said satellite. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
-
Specification