Symbol switching of CDMA channels

• US 5,805,579 A
• Filed: 05/06/1996
• Issued: 09/08/1998
• Est. Priority Date: 05/06/1996
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Miller, Robert Raymond II, Gerakoulis, Diakoumis Parissis, Erving, Richard Henry
• Primary Examiner(s): Jung, Min
• Application Number:
  US08/643,720
• Time in Patent Office: 855 Days
• Field of Search: 370/320, 370/325, 370/342, 370/335, 370/323, 370/324, 370/315, 370/316, 370/441, 455/12.1, 455/13.1
• US Class Current: 370/320
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]

Abstract

A digital switch included within a satellite, processes uplink beams and the included traffic channels at a symbol level instead at a bit level. In this system the switch performs as a repeater on the per user basis and as a switch at the beam level. Individual user signals (i.e., channels) are separated from the uplink beam and recombined into the appropriate downlink beam.

Claims

1. A satellite based switching system for coupling user channels in an uplink CDMA beam to a downlink CDMA beam;

comprising;

means for receiving from a transmitting ground station the uplink CDMA beam and separating individual channels from the uplink beam by use of CDMA codes of individual channels included within the CDMA uplink beam;

means for extracting symbols from the uplink channels;

means for switching the uplink channels at a symbol level;

means for combining the symbol levels of uplink channels into downlink CDMA beams;

means for transmitting the downlink CDMA beams to a receiving ground station.

2. A switching system for coupling user channels in an incoming modulated beam to an outgoing modulated beam, each beam including a plurality of user channels, comprising:

means for sampling the incoming beam;

means for processing the samples on a per user basis to extract symbol information;

means for switching, by using CDMA codes of individual channels, the symbol information for routing to an appropriate output beam;

means for combining user symbols;

means for reconstructing a sampled waveform from combined user symbols for outgoing transmission as a beam.

3. A method of coupling user channels from incoming modulated beams to outgoing modulated beams, comprising the steps of:

sampling the incoming beam;

processing the samples on a per user basis to extract symbol information;

switching, by using CDMA codes of individual channels, the symbol information for routing to an appropriate output beam;

combining user symbols;

reconstructing a sampled waveform from combined user symbols for outgoing transmission as a beam.

4. A method of switching user channels in the sky from an uplink incoming modulated beam to an output downlink modulated beam, comprising the steps of:

generating symbols which represent information in each user channel;

switching symbols of each uplink user channel to a downlink beam, b using CDMA codes of individual channels, to a downlink beam having a destination in common with a predetermined destination of the user channel.

5. A switching system in the sky for switching uplink user channels extracted from uplink beams into downlink beams having a destination with a predetermined destination of aggregated uplink user channels forming the downlink beams;

comprising;

means for sampling the uplink beams;

means for processing the samples on a per user basis to generate symbol information representing each user channel;

means for switching the symbol information to aggregate uplink user channels with a common destination predetermined, into downlink beams having a destination in common with the predetermined destinations of the user channels it contains, by using CDMA codes of individual channels.

6. A satellite based switching system for coupling user channels in an uplink CDMA beam to a downlink CDMA beam;

comprising;

means for receiving from a transmitting ground station the uplink CDMA beam and separating individual channels from the uplink beam;

means for extracting symbols from the uplink channels;

means for switching the uplink channels at a symbol level;

means for combining the symbol levels of uplink channels into downlink CDMA beams, by including means for sampling a representation of the symbol, switch processing the sample and reconstituting the symbol following switch processing; and

means for transmitting the downlink CDMA beams to a receiving ground station.

7. A satellite based switching system for coupling user channels in an uplink CDMA beam to a downlink CDMA beam;

comprising;

means for receiving from a transmitting ground station the uplink CDMA beam and separating individual channels from the uplink beam;

means for extracting symbols from the uplink channels by modulating a channel by phase shift keying to obtain symbols of bit combinations;

means for switching the uplink channels at a symbol level;

means for combining the symbol levels of uplink channels into downlink CDMA beams;

means for transmitting the downlink CDMA beams to a receiving ground station.

8. A method of switching user channels in the sky from an uplink incoming modulated beam to an output downlink modulated beam;

comprising the steps of;

generating symbols which represent information in each user channel, by sampling an uplink incoming modulated beam and processing the samples on a per user basis to extract symbol information;

switching symbols of each uplink user channel to a downlink beam having a destination in common with a predetermined destination of the user channel.

9. A method of switching user channels in the sky from an uplink incoming modulated beam to an output downlink modulated beam;

comprising the steps of;

generating symbols which represent information in each user channel;

switching symbols of each uplink user channel to a downlink beam having a destination in common with a predetermined destination of the user channel;

reconstructing a sampled waveform from the switched symbols for transmission in the downlink beam.

10. A method of switching user channels in the sky from an uplink incoming modulated beam to an output downlink modulated beam;

comprising the steps of;

generating symbols which represent information in each user channel by generating symbols representing bit combinations by phase shift keying;

switching symbols of each uplink user channel to a downlink beam having a destination in common with a predetermined destination of the user channel.

11. A switching system in the sky for switching uplink user channels extracted from uplink beams into downlink beams having a destination with a predetermined destination of aggregated uplink user channels forming the downlink beams;

comprising;

means for sampling the uplink beams;

means for processing the samples on a per user basis to generate symbol information representing each user channel;

means for separating individual channels from the uplink beams;

means for switching the symbol information to aggregate uplink user channels with a common destination predetermined, into downlink beams having a destination in common with the predetermined destinations of the user channels it contains; and

including means for processing switching with samples of a symbol level and means for reconstituting symbols following switching.