Configurable block CDMA scheme
In an apparatus and method for generating a SC-FDMA signal having a sequence of symbols, a signal is generated by spreading blocks of symbols using a spreading code, then applying an inverse discrete Fourier transform (IDFT) to the symbols, followed by rotating the phase of each symbol, and applying a guard interval in the form of a cyclic prefix (CP), such that the spreading code is selected from sequences having a DFT matrix and Hadamard-Walsh sequence, and whereby the difference between the amounts for rotating the phase of adjacent symbols is constant. The spreading may be changed so as to change the data rate for each transmitter.
1. A method of generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols, the method comprising:
spreading blocks of symbols by applying a spreading code;
applying an inverse discrete Fourier transform (IDFT) to the symbols;
rotating a phase of each symbol by transmitter-dependent amounts; and
applying a guard interval in the form of a cyclic prefix (CP),
wherein the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
2. The method according to claim 1 , wherein a length of the spreading code is changed so as to change a data rate for each transmitter.
3. The method according to claim 1 , further comprising:
utilizing a plurality of antennas for transmission.
4. A method of generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols, the method comprising:
spreading blocks of symbols by applying a spreading code;
applying an inverse discrete Fourier transform (IDFT) to the symbols;
rotating a phase of each symbol; and
applying a guard interval in the form of a cyclic prefix (CP), wherein
the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
5. The method according to claim 4 , wherein a length of the spreading code is changed so as to change the data rate for each transmitter.
6. The method according to claim 4 further comprising:
utilizing a plurality of antennas for transmission.
7. A method of generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols, the method comprising:
interleaving the symbols;
mapping the symbols to M-PSK symbols, where M is a number of elements in a constellation;
spreading blocks of symbols by applying a spreading code;
applying an inverse discrete Fourier transform (IDFT) to symbols;
rotating a phase of each symbol; and
applying a guard interval in the form of a cyclic prefix (CP), wherein
the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
8. The method according to claim 7 , wherein a length of the spreading code is changed so as to change the data rate for each transmitter.
9. The method according to claim 7 , further comprising:
utilizing a plurality of antennas for transmission.
10. A transmitter for generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols, the transmitter comprising:
a spreading unit configured to spread blocks of symbols by applying a spreading code;
a transmitting unit configured to apply an inverse discrete Fourier transform (IDFT) to the symbols;
a rotating unit configured to rotate a phase of each symbol by transmitter-dependent amounts; and
a guard interval unit configured to apply a guard interval in the form of a cyclic prefix (CP), wherein
the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
11. The transmitter according to claim 10 , wherein a length of the spreading code is changed so as to change the data rate for each transmitter.
12. The transmitter according to claim 10 further comprising:
a plurality of antennas for transmission.
13. A transmitter for generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols, the transmitter comprising:
a spreading unit configured to spread blocks of symbols by applying a spreading code;
a transmitting unit configured to apply an inverse discrete Fourier transform (IDFT) to the symbols;
a rotating unit configured to rotate a phase of each symbol; and
a guard interval unit configured to apply a guard interval in the form of a cyclic prefix (CP),
wherein the spreading code is one selected from sequences comprising a IDFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
14. The transmitter according to claim 13 , wherein a length of the spreading codes is changed so as to change the data rate for each transmitter.
15. The transmitter according to claim 13 , further comprising:
a plurality of antennas for transmission.
16. A transmitter for generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols comprising:
an interleave unit configured to interleave the symbols;
a mapping unit configured to map the symbols to M-PSK symbols, M being a number of elements in a constellation;
a spreading unit configured to spread blocks of symbols by applying a spreading code:
a transmitting unit configured to apply an inverse discrete Fourier transform (IDFT) to the symbols;
a rotating unit configured to rotate a phase of each symbol by transmitter-dependent amounts; and
a guard interval unit configured to apply a guard interval in the form of a cyclic prefix (CP), wherein
the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
17. The transmitter according to claim 16 , wherein a length of the spreading code is changed so as to change the data rate for each transmitter.
18. The transmitter according to claim 16 , further comprising:
a plurality of antennas for transmission.
19. A method of generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols, the method comprising:
mapping the symbols to M-PSK symbols, M being a number of elements in a constellation;
spreading blocks of symbols by applying a spreading code;
applying an inverse discrete Fourier transform (IDFT) to symbols;
rotating a phase of each symbol by transmitter-dependent amounts; and
applying a guard interval in the form of a cyclic prefix (CP), wherein
the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
20. The method according to claim 19 , wherein
the length of the user-specific spreading codes may change so as to change the data rate for each transmitter.
21. The method according to claim 19 further comprising:
utilizing a plurality of antennas for transmission.
22. A transmitter for generating a single-carrier frequency division multiple access (SC-FDMA) signal comprising a sequence of symbols comprising;
mapping unit configured to map symbols to M-PSK symbols, M being a number of elements in a constellation;
a spreading unit configured to spread blocks of symbols by applying a spreading code;
a transmitting unit configured to apply an inverse discrete Fourier transform (IDFT) to the symbols;
a rotating unit configured to rotate a phase of each symbol by transmitter-dependent amounts; and
a guard interval unit configured to apply a guard interval in the form of a cyclic prefix (CP), wherein
the spreading code is one selected from sequences comprising a DFT matrix and Hadamard-Walsh sequences, and
a first difference between the amounts of phase rotations of a first pair of adjacent symbols is the same as a second difference between the amounts of phase rotations of a second pair of adjacent symbols.
23. The transmitter according to claim 22 , wherein
the length of the user-specific spreading codes may change so as to change the data rate for each transmitter.
24. The transmitter according to claim 22 further comprising:
a plurality of antennas for transmission.