Variable throughput reduction spread-spectrum communications

1. A spread-spectrum system comprising:

a demultiplexer for demultiplexing input data into a plurality of data channels;

a plurality of forward-error-correction encoders and interleavers for FEC encoding and interleaving the plurality of data channels as a plurality of FEC encoded and interleaved channels, respectively;

a plurality of spread-spectrum processors for spread-spectrum processing the plurality of FEC encoded and interleaved channels as a plurality of spread-spectrum channels, employing a plurality of chip-sequence signals;

a combiner for combining the plurality of spread-spectrum channels as a code-division-multiplexed signal;

a modulator for transmitting the code-division-multiplexed signal having the plurality of spread-spectrum channels, over a communications channel;

a plurality of spread-spectrum despreaders for despreading the code-division-multiplexed signal into a plurality of despread channels, respectively;

a multiplicity of adders, electronically controlled by an adder-control signal, for adding at least two despread channels to generate a multiplicity of added channels;

a multiplicity of FEC decoder and de-interleavers for generating a syndrome signal from an error rate of the multiplicity of added channels, and for FEC decoding and de-interleaving the multiplicity of added channels, and a multiplicity of decoded channels;

a command processor, responsive the syndrome signal, for determining a desired-data rate, for generating a data-rate command signal having the desired data rate, for generating the adder-control signal for adding together a number of despread channels of the plurality of despread channels, and for generating a multiplexer signal having a number of decoded channels to multiplex together; and

a multiplexer for multiplexing the multiplicity of decoded channels and an estimate of the input data.

2. The spread-spectrum system as set forth in claim 1 further including a buffer, coupled before the demultiplexer, for storing input data prior to demultiplexing the input data.

3. The spread-spectrum system as set forth in claim 1 , with said plurality of spreaders including:

a chip-sequence generator for generating the plurality of orthogonal chip-sequence signals; and

a plurality of product devices, coupled to said chip-sequence generator, for spread-spectrum processing the plurality of encoded channels as the plurality of spread-spectrum channels.

4. The spread-spectrum system as set forth in claim 1 , with said plurality of spreaders including:

a chip-sequence generator for generating the plurality of quasi-orthogonal chip-sequence signals; and

a plurality of product devices, coupled to said chip-sequence generator, for spread-spectrum processing the plurality of encoded channels as the plurality of spread-spectrum channels.

5. The spread-spectrum system as set forth in claim 1 , with said plurality of despreaders further including:

a chip-sequence generator for generating a replica of the plurality of chip-sequence signals; and

a plurality of product devices, coupled to said chip-sequence generator, for despreading the code-division-multiplexed signal as a plurality of despread channels.

6. The spread-spectrum system as set forth in claim 1 , with said plurality of despreaders including a plurality a matched filters, having a plurality of impulse responses matched to the plurality of chip-sequence signals, respectively.

7. The spread-spectrum system as set forth in claim 1 , with said plurality of despreaders including a plurality a surface acoustic wave (SAW) devices, having a plurality of impulse responses matched to the plurality of chip-sequence signals, respectively.

8. A spread-spectrum system comprising:

demultiplexer means for demultiplexing input data into a plurality of data channels;

encoder means for FEC encoding and interleaving the plurality of data channels as a plurality of FEC encoded and interleaved channels, respectively;

spreader means for spread-spectrum processing the plurality of FEC encoded and interleaved channels as a plurality of spread-spectrum channels, having a plurality of chip-sequence signals;

combiner means for combining the plurality of spread-spectrum channels as a code-division-multiplexed signal;

modulator means for transmitting the code-division-multiplexed signal having the plurality of spread-spectrum channels, over a communications channel;

despreader means for despreading the code-division-multiplexed signal into a plurality of despread channels, respectively;

adder means, electronically controlled by an adder-control signal, for adding at least two despread channels to generate a multiplicity of added channels;

decoder means for generating a syndrome signal from an error rate of the multiplicity of added channels, and for FEC decoding and de-interleaving the multiplicity of added channels, and a multiplicity of decoded channels;

command means, responsive the syndrome signal, for determining a desired-data rate, for generating a data-rate command signal having the desired data rate, for generating the adder-control signal for adding together a number of despread channels of the plurality of despread channels, and for generating a multiplexer signal having a number of decoded channels to multiplex together; and

multiplexer means for multiplexing the multiplicity of decoded channels and an estimate of the input data.

9. The spread-spectrum system as set forth in claim 8 further including a buffer, coupled before said demultiplexer means, for storing input data prior to demultiplexing the input data.

10. The spread-spectrum system as set forth in claim 8 , with said spreader means including:

a chip-sequence generator for generating the plurality of orthogonal chip-sequence signals; and

a plurality of product devices, coupled to said chip-sequence generator, for spread-spectrum processing the plurality of encoded channels as the plurality of spread-spectrum channels.

11. The spread-spectrum system as set forth in claim 8 , with said spreader means including:

a chip-sequence generator for generating the plurality of quasi-orthogonal chip-sequence signals; and

a plurality of product devices, coupled to said chip-sequence generator, for spread-spectrum processing the plurality of encoded channels as the plurality of spread-spectrum channels.

12. The spread-spectrum system as set forth in claim 8 , with said despreader means further including:

a chip-sequence generator for generating a replica of the plurality of chip-sequence signals; and

a plurality of product devices, coupled to said chip-sequence generator, for despreading the code-division-multiplexed signal as a plurality of despread channels.

13. The spread-spectrum system as set forth in claim 8 , with said despreader means including a plurality a matched filters, having a plurality of impulse responses matched to the plurality of chip-sequence signals, respectively.

14. The spread-spectrum system as set forth in claim 8 , with said despreader means including a plurality a surface acoustic wave (SAW) devices, having a plurality of impulse responses matched to the plurality of chip-sequence signals.

15. A spread-spectrum method comprising the steps of:

demultiplexing input data into a plurality of data channels;

FEC encoding and interleaving the plurality of data channels as a plurality of EC encoded and interleaved channels, respectively;

spread-spectrum processing the plurality of FEC encoded and interleaved channels as a plurality of spread-spectrum channels, employing a plurality of chip-sequence signals;

combining the plurality of spread-spectrum channels as a code-division-multiplexed signal;

transmitting the code-division-multiplexed signal having the plurality of spread-spectrum channels, over a communications channel;

despreading the code-division-multiplexed signal into a plurality of despread channels, respectively;

adding at least two despread channels to generate a multiplicity of added channels;

generating a syndrome signal from an error rate of the multiplicity of added channels;

FEC decoding and de-interleaving the multiplicity of added channels, and a multiplicity of decoded channels;

determining, in response to the syndrome signal, a desired-data rate;

generating a data-rate command signal having the desired data rate;

generating, in response to the syndrome signal, the adder-control signal for adding together a number of despread channels of the plurality of despread channels;

generating, in response to the syndrome signal, a multiplexer signal having a number of decoded channels to multiplex together;

multiplexing the multiplicity of decoded channels and an estimate of the input data.

16. The spread-spectrum method as set forth in claim 15 further including, before the step of demultiplexing, the step of storing input data prior to demultiplexing the input data.

17. The spread-spectrum method as set forth in claim 15 , with the step of spread-spectrum processing including the steps of:

generating the plurality of orthogonal chip-sequence signals; and

spread-spectrum processing the plurality of encoded channels as the plurality of spread-spectrum channels.

18. The spread-spectrum method as set forth in claim 15 , with the step of spread-spectrum processing including the steps of:

generating the plurality of quasi-orthogonal chip-sequence-signals; and

spread-spectrum processing the plurality of encoded channels as the plurality of spread-spectrum channels.

19. The spread-spectrum method as set forth in claim 15 , with the step of despreading further including the steps of:

generating a replica of the plurality of chip-sequence signals; and

despreading the code-division-multiplexed signal as a plurality of despread channels.

20. The spread-spectrum method as set forth in claim 15 , with the step of despreading including the step of filtering, with a plurality of impulse responses matched to the plurality of chip-sequence signals, respectively.