Adaptative multi-carrier code division multiple access
A system for performing adaptative multi-carrier code division multiple access (AMC-CDMA) includes first circuitry and modulator circuitry. The first circuitry determines a channel performance metric for each of a plurality of channels. The first circuitry determines at least one parameter of bit loading for each of the channels based on the channel performance metric. The modulator circuitry modulates AMC-CDMA signals using the parameters for bit loading in each of the channels for transmission over a wired connection.
1. A system for performing adaptative multi-carrier code division multiple access (AMC-CDMA), the system comprising:
first circuitry configured to determine a channel performance metric for each of a plurality of carriers further configured to determine a number of CDMA sequences over the carrier, a length of a CDMA sequence, and a number of bits of a constellation of modulation, at least one of which being determined based on the determined channel performance metric; and
modulator circuitry configured to modulate AMC-CDMA signals using the determined number of CDMA sequences over the carrier, a length of a CDMA sequence, and a number of bits of a constellation of modulation in each of the carriers for transmission over a wired connection.
2. The system of claim 1 wherein the channel performance metric comprises signal-to-noise ratio.
3. The system of claim 1 wherein the channel performance metric comprises bit error rate.
4. The system of claim 1 wherein the wired connection comprises a power line connection.
5. The system of claim 1 further comprising converter circuitry configured to convert a serial signal to a parallel signal.
6. The system of claim 1 further comprising code generator circuitry configured to generate codes for the AMC-CDMA signals.
7. The system of claim 1 further comprising inverse fast fourier transform (IFFT) circuitry configured to perform IFFT functions on the AMC-CDMA signals.
8. The system of claim 1 further comprising receiver circuitry configured to receive and decode the AMC-CDMA signals.
9. A method for performing adaptative multi-carrier code division multiple access (AMC-CDMA), the system comprising:
determining a channel performance metric for each of a plurality of carriers;
determining for each carrier of a plurality of carriers a number of CDMA sequences over the carrier, a length of a CDMA sequence, and a number of bits of a constellation of modulation, at least one of which being determined based on the determined channel performance metric; and
modulating the AMC-CDMA signals using the determined number of CDMA sequences over the carrier, a length of a CDMA sequence, and a number of bits of a constellation of modulation in each of the carriers; and
transmitting the AMC-CDMA signals over a wired connection.
10. The method of claim 8 wherein the channel performance metric comprises signal-to-noise ratio.
11. The method of claim 9 wherein the channel performance metric comprises bit error rate.
12. The method of claim 9 wherein the wired connection comprises a power line connection.
13. The method of claim 9 further comprising converting a serial signal to a parallel signal.
14. The method of claim 9 further comprising generating codes for the AMC-CDMA signals.
15. The method of claim 9 further comprising performing inverse fast fourier transform (IFFT) functions on the AMC-CDMA signals.
16. The method of claim 9 further comprising receiving and decoding the AMC-CDMA signals.
17. A transmitter comprising:
a bit loading memory;
firmware configured to measure a channel performance metric for each of a plurality of carriers;
circuitry configured to
determine a number of CDMA sequences for each of the plurality of carriers, each number of CDMA sequences being determined based on the channel performance metric measured for that carrier,
determine a length of a CDMA sequence for each carrier of a plurality of carriers;
determine a number of bits of a constellation of modulation for each carrier of a plurality of carriers;
store the number of CDMA sequences for each carrier in the bit loading memory; modulator circuitry configured to modulate a signal in each of the plurality of carriers based on the number of CDMA sequences, the length of the CDMA sequence and the number of bits of a constellation of modulation for each carrier; and
a power line connection configured to couple the modulator circuitry to a power line.
18. The transmitter of claim 17 further comprising a serial to parallel converter configured to receive a gigabit bit stream and a number of virtual carriers and further configured to divide the gigabit bit stream into the number of virtual carriers and provide the divided gigabit bit stream to the modulator circuitry.
19. The transmitter of claim 18 wherein the number of virtual carriers is calculated based on a total number of CDMA sequences.
20. The transmitter of claim 18 further comprising a pseudo noise generator configured to generate a pseudo noise code for each of the number of virtual carriers, and a summarizer configured to receive the dot products of the PN codes with the modulated carrier signals output by the modulator circuitry and further configured to receive the number of CDMA sequences for a frequency.