Multicarrier sub-layer for direct sequence channel and multiple-access coding
Carrier Interferometry (CI) provides wideband transmission protocols with frequency-band selectivity to improve interference rejection, reduce multipath fading, and enable operation across non-continuous frequency bands. Direct-sequence protocols, such as DS-CDMA, are provided with CI to greatly improve performance and reduce transceiver complexity. CI introduces families of orthogonal polyphase codes that can be used for channel coding, spreading, and/or multiple access. Unlike conventional DS-CDMA, CI coding is not necessary for energy spreading because a set of CI carriers has an inherently wide aggregate bandwidth. Instead, CI codes are used for channelization, energy smoothing in the frequency domain, and interference suppression. CI-based ultra-wideband protocols are implemented via frequency-domain processing to reduce synchronization problems, transceiver complexity, and poor multipath performance of conventional ultra-wideband systems. CI allows wideband protocols to be implemented with space-frequency processing and other array-processing techniques to provide either or both diversity combining and sub-space processing. CI also enables spatial processing without antenna arrays. Even the bandwidth efficiency of multicarrier protocols is greatly enhanced with CI. CI-based wavelets avoid time and frequency resolution trade-offs associated with conventional wavelet processing. CI-based Fourier transforms eliminate all multiplications, which greatly simplifies multi-frequency processing. The quantum-wave principles of CI improve all types of baseband and radio processing.
1. A method of communication in a wireless communication network that employs a first set of complex-valued codes to encode data symbols to be transmitted, and employs a second set of complex-valued codes to recover transmitted data symbols from a received signal, the method comprising:
selecting a plurality of subcarriers to be transmitted;
encoding the data symbols with the first set of complex-valued codes to produce encoded data symbols;
applying the encoded data symbols to the plurality of subcarriers to produce a spread-Orthogonal Frequency Division Multiplexing (OFDM) signal; and
transmitting the spread-OFDM signal;
wherein the first set of complex-valued codes are complex conjugates of the second set of complex-valued codes.
2. The method of claim 1 , wherein selecting is responsive to spectrum allocation or is configured to provide for orthogonal frequency division multiple access.
3. The method of claim 1 , wherein selecting comprises selecting subcarrier frequency spacing.
4. The method of claim 1 , wherein an inverse discrete Fourier transform (IDFT) produces the spread-OFDM signal, and selecting comprises providing a set of zero and non-zero values to input frequency bins of the IDFT.
5. The method of claim 1 , wherein selecting comprises selecting subcarriers for control signaling or pilot tones.
6. The method of claim 1 , wherein the plurality of subcarriers are contiguous subcarriers or interleaved subcarriers.
7. The method of claim 1 , wherein encoding comprises multiplying a vector or matrix of data symbols with a vector or matrix comprising the first set of complex-valued codes.
8. The method of claim 1 , wherein applying comprises modulating the encoded data symbols onto the plurality of subcarriers.
9. The method of claim 1 , further comprising adding a cyclic prefix to the spread-OFDM signal before transmitting the spread-OFDM signal.
10. An apparatus for communication in a wireless communication network that employs a first set of complex-valued codes to encode data symbols to be transmitted, and employs a second set of complex-valued codes to recover transmitted data symbols from a received signal, the apparatus comprising:
at least one processor; and
a non-transitory computer-readable memory communicatively coupled to the at least one processor, the non-transitory computer-readable memory including a set of instructions stored thereon and executable by the at least one processor for:
selecting a plurality of subcarriers to be transmitted;
encoding the data symbols with the first set of complex-valued codes to produce encoded data symbols;
applying the encoded data symbols to the plurality of subcarriers to produce a spread-Orthogonal Frequency Division Multiplexing (OFDM) signal; and
transmitting the spread-OFDM signal;
wherein the first set of complex-valued codes are complex conjugates of the second set of complex-valued codes.
11. The apparatus of claim 10 , wherein selecting is responsive to spectrum allocation or is configured to provide for orthogonal frequency division multiple access.
12. The apparatus of claim 10 , wherein selecting comprises selecting frequency spacing of the plurality of subcarriers.
13. The apparatus of claim 10 , wherein an inverse discrete Fourier transform (IDFT) produces the spread-OFDM signal, and selecting comprises providing a set of zero and non-zero values to input frequency bins of the IDFT.
14. The apparatus of claim 10 , wherein selecting comprises selecting subcarriers for control signaling or pilot tones.
15. The apparatus of claim 10 , wherein the plurality of subcarriers are contiguous subcarriers or interleaved subcarriers.
16. The apparatus of claim 10 , wherein encoding comprises multiplying a vector or matrix of data symbols with a vector or matrix comprising the first set of complex-valued codes.
17. The apparatus of claim 10 , wherein applying comprises modulating the encoded data symbols onto the plurality of subcarriers.
18. The apparatus of claim 10 , wherein the non-transitory computer-readable memory further includes instructions stored thereon and executable by the processor for adding a cyclic prefix to the spread-OFDM signal before transmitting the spread-OFDM signal.
19. A computer program product for operating a transmitter in a wireless communication network that employs a first set of complex-valued codes to encode data symbols to be transmitted, and employs a second set of complex-valued codes to recover transmitted data symbols from a received signal, the computer program product comprising a non-transitory computer readable storage device having computer readable program code stored therein, said program code containing instructions executable by one or more processors of a computer system for:
selecting a plurality of subcarriers to be transmitted;
encoding the data symbols with the first set of complex-valued codes to produce encoded data symbols;
applying the encoded data symbols to the plurality of subcarriers to produce a spread-Orthogonal Frequency Division Multiplexing (OFDM) signal; and
transmitting the spread-OFDM signal;
wherein the first set of complex-valued codes are complex conjugates of the second set of complex-valued codes.
20. The computer program product of claim 19 , wherein selecting is responsive to spectrum allocation or is configured to provide for orthogonal frequency division multiple access.
21. The computer program product of claim 19 , wherein selecting comprises selecting frequency spacing of the plurality of subcarriers.
22. The computer program product of claim 19 , wherein an inverse discrete Fourier transform (IDFT) produces the spread-OFDM signal, and selecting comprises providing a set of zero and non-zero values to input frequency bins of the IDFT.
23. The computer program product of claim 19 , wherein selecting comprises selecting subcarriers for control signaling or pilot tones.
24. The computer program product of claim 19 , wherein the plurality of subcarriers are contiguous subcarriers or interleaved subcarriers.
25. The computer program product of claim 19 , wherein encoding comprises multiplying a vector or matrix of data symbols with a vector or matrix comprising the first set of complex-valued codes.
26. The computer program product of claim 19 , wherein applying comprises modulating the encoded data symbols onto the plurality of subcarriers.
27. The computer program product of claim 19 , wherein said program code further includes instructions executable by the one or more processors of the computer system for adding a cyclic prefix to the spread-OFDM signal before transmitting the spread-OFDM signal.