Multi-channel spread spectrum communications system

• US 20030235148A1
• Filed: 06/19/2002
• Published: 12/25/2003
• Est. Priority Date: 06/19/2002
• Status: Active Grant

• Current Assignee: George L. Yang
• Original Assignee: George L. Yang
• Inventors: Yang, George L.
• Granted Patent: US 7,242,663 B2
• Time in Patent Office: Days
• US Class Current: 370/206
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/0077 Multicode, e.g. multiple codes assigned to one user

Abstract

A multi-channel spread spectrum communications system utilizes the combination of spreading codes to represent and transfer information. On the transmitter side, every block of data bits is divided into two sub-blocks of data bits. One sub-block is mapped to a number of spreading codes, while another sub-block is separated further into several smaller sub-blocks with each of them mapped into an M-ary phase. Each selected spreading code is modulated by the corresponding M-ary phase. On the receiver side, first determine the most likely transmitted spreading codes and their respective phases, then reverse map the set of estimated transmitted spreading codes into a block of bits and each of the phases into another block of data bits, and finally combine all these blocks to a single block of data bits.

Claims

1. A multi-channel communications system, comprising:

a mapping device at transmitter for mapping a block of data bits into an element of the power set of the set of transmittable signals;

a detection device at receiver for determining the likely transmitted element from the power set of the set of transmittable signals; and

a reverse mapping device at receiver for reverse mapping the likely transmitted element of the power set of the set of transmittable signals into a block of data bits.

2. A multi-channel communications system as in claim 1, wherein the transmittable signals comprises spreading signals.

3. A multi-channel communications system as in claim 2, further comprising:

a bit separating device for dividing a block of data bits into several smaller blocks of bits;

a plurality of submodulators for modulating each of the spreading codes of an element of the power set with the signal mapped from the corresponding smaller block;

a plurality of subdemodulators for demodulating the signal associated with each of the spreading code of an element of the power set into a block of data bits; and

a bit combining device for combining a plurality of blocks of data bits together.

4. A multi-channel communications system as in claim 3, wherein each of the submodulators comprises an M-ary PSK modulator.

5. A multi-channel communications system as in claim 3, wherein each of the submodulators comprises a QAM modulator.

6. A multi-channel communications system as in claim 3, wherein each of the submodulators comprises a PAM modulator.

7. A multi-channel communications system as in claim 3, wherein each of the subdemodulators comprises an M-ary PSK demodulator.

8. A multi-channel communications system as in claims 3, wherein each of the subdemodulators comprises a QAM demodulator.

9. A multi-channel communications system as in claims 3, wherein each of the subdemodulators comprises a PAM demodulator.

10. A method of transmitting and receiving a block of data bits comprising:

separating the block of data bits into a plurality sub-blocks of data bits;

mapping one of the sub-blocks into an element of the power set of the set of spreading codes;

mapping each of the rest sub-blocks into a signal corresponding to the data bits in the sub-block;

multiplying each of the spreading codes of said element with the corresponding signal to form a product;

combining all the products to obtain a summation;

modulating the summation with carrier and transmitting over a link;

demodulating the received signals by multiplying it by the signals from local oscillator;

detecting the most likely transmitted element of the power set of the set of spreading codes and signal associated with each of the spreading codes of the element;

reverse mapping the most likely transmitted element into a first block of data bits;

reverse mapping the signal associated with each of the spreading codes of the most likely transmitted element into a second block of data bits; and

combining the first block of data bits with a plurality of second blocks of data bits to form a new block of data bits.

11. A method as in claim 10, wherein mapping each of the rest sub-blocks into a signal, the signal comprises a complex number corresponding to the phase represented by the sub-block of data bits.

12. A method as in claim 10, wherein mapping each of the rest sub-blocks into a signal, the signal comprises a complex number generated by QAM modulator corresponding to the sub-block of data bits.

13. A method as in claim 10, wherein mapping each of the rest sub-blocks into a signal, the signal comprises a number generated by PAM modulator.

14. A method as in claim 10, wherein reverse mapping the signal associated with each of the spreading codes, the signal comprises a complex number corresponding to the phase associated with corresponding spreading code.

15. A method as in claim 10, wherein reverse mapping the signal associated with each of the spreading codes, the signal comprises a complex number corresponding to the real amplitude and imagery amplitude associated with the corresponding spreading code.

16. A method as in claim 10, wherein reverse mapping the signal associated with each of the spreading codes, the signal is the magnitude associated with the corresponding spreading code.

17. A method of automatic rate detection comprising:

associating different symbol repetition to a corresponding extra element of the power set of the set of transmittable signals;

transmitting the extra element corresponding to the desired symbol repetition;

detecting the transmitted extra element; and

finding the intended symbol repetition by checking the repetition associated with the received extra element.