Multiple access spread spectrum switching methodology
A low-cost, low-power, low-complexity, small, high-reliability, robust, seamless satellite communication network is described. The network performs encoding of a user signal at the customer premises to enable routing of the user signal to an appropriate destination beam at the satellite requiring low power user signal processing. Routing information is embedded at the periphery of the network CPE's rather than at the satellite. Embedding the routing information in this way greatly reduces on-board switching complexity and increases signal to interference ratio for the user.
1. Destination equipment for receiving a plurality of encoded user signals including a specific encoded user signal, the specific encoded user signal being contained in a particular destination beam of a plurality of destination beams transmitted from on-board satellite equipment, the destination equipment comprising:
a first digital decoder comprising a processor and computer readable media containing computer readable instructions that, when executed by the processor, cause the first digital decoder to apply on the plurality of encoded user signals an orthogonal code previously applied to the particular destination beam by the on-board satellite equipment, wherein applying the orthogonal code extracts a subset of the plurality of encoded user signals that are received in the particular destination beam, to create a first intermediate digital signal; and
a second digital decoder comprising a processor and computer readable media containing computer readable instructions that, when executed by the processor, cause the second digital decoder to apply on the first intermediate digital signal a destination user code previously applied to the specific encoded user signal by a terrestrial transmitter prior to a transmission to the on-board satellite equipment, wherein applying the destination user code extracts the specific encoded user signal from the subset of the plurality of encoded user signals.
2. The destination equipment of claim 1 , further comprising:
a low-noise amplifier, a filter and a down-converter connected between an antenna and the first digital decoder to receive a radio signal from the antenna and to isolate the plurality of encoded user signals from the radio signal.
3. The destination equipment of claim 2 , further comprising a demodulator for demodulating an output of the low-noise amplifier, filter and down-converter.
4. The destination equipment of claim 1 , further comprising:
baseband processing devices connected to the second digital decoder for producing an output signal for delivery to customer premises equipment.
5. The destination equipment of claim 1 , wherein the first and second digital decoders are code division multiple access decoders.
6. The destination equipment of claim 1 , wherein the destination user is a code division multiple access spreading code.
7. The destination equipment of claim 1 , wherein the destination user code is a code selected from the group consisting of a gold code, a Walsh code and a PN sequence.
8. The destination equipment of claim 1 , wherein use of the orthogonal code improves a signal-to-interference ratio of the particular destination beam.
9. The destination equipment of claim 1 , wherein the first digital decoder is one of a plurality of digital decoders applying respective orthogonal codes on the plurality of encoded user signals, each respective orthogonal code being unique to a respective particular destination beam, each respective digital decoder being for extracting a respective subset of the plurality of encoded user signals that are received in the respective particular destination beam.
10. The destination equipment of claim 1 , wherein applying the orthogonal code rejects encoded user signals of the plurality of encoded user signals that are not received in the particular destination beam.
11. A method for receiving a plurality of encoded user signals including a specific encoded user signal, the specific encoded user signal being contained in a particular destination beam of a plurality of destination beams transmitted from on-board satellite equipment, the method comprising:
by a first digital decoder, applying on the plurality of encoded user signals an orthogonal code previously applied to the particular destination beam by the on-board satellite equipment, wherein applying the orthogonal code extracts a subset of the plurality of encoded user signals that are received in the particular destination beam, to create a first intermediate digital signal; and
by a second digital decoder, applying on the first intermediate digital signal a destination user code previously applied to the specific encoded user signal by a terrestrial transmitter prior to a transmission to the on-board satellite equipment, wherein applying the destination user code extracts the specific encoded user signal from the subset of the plurality of encoded user signals.
12. The method of claim 11 , further comprising:
by low-noise amplifier, a filter and a down-converter connected between an antenna and the first digital decoder, receiving a radio signal from the antenna and isolating the plurality of encoded user signals from the radio signal.
13. The method of claim 12 , further comprising:
demodulating an output of the low-noise amplifier, filter and down-converter.
14. The method of claim 11 , further comprising:
by a baseband processing device connected to the second digital decoder, producing an output signal for delivery to customer premises equipment.
15. The method of claim 11 , wherein the first and second digital decoders are code division multiple access decoders.
16. The method of claim 11 , wherein the destination user is a code division multiple access spreading code.
17. The method of claim 11 , wherein the destination user code is a code selected from the group consisting of a gold code, a Walsh code and a PN sequence.
18. The method of claim 11 , wherein use of the orthogonal code improves a signal-to-interference ratio of the particular destination beam.
19. The method of claim 11 , wherein the first digital decoder is one of a plurality of digital decoders applying respective orthogonal codes on the plurality of encoded user signals, each respective orthogonal code being unique to a respective particular destination beam, each respective digital decoder being for extracting a respective subset of the plurality of encoded user signals that are received in the respective particular destination beam.
20. The method of claim 11 , wherein applying the orthogonal code rejects encoded user signals of the plurality of encoded user signals that are not received in the particular destination beam.