1. A physical layer module comprising:
a mapping module configured to map a plurality of coded data streams to a plurality of transmit antennas, wherein each transmit antenna is associated with a respective radio frequency channel of a plurality of radio frequency channels; and
a plurality of gain modules in communication with the mapping module,
wherein each gain module
(i) is associated with a respective radio frequency channel of the plurality of radio frequency channels, and
(ii) is configured to apply a complex gain to the coded data stream mapped to the respective radio frequency channel associated with the gain module, wherein the complex gain applied by the gain module (i) differs relative to that applied by other gain modules and (ii) corresponds to the transmit antenna associated with the respective radio frequency channel.
2. The physical layer module of claim 1, further comprising a plurality of cyclic delay modules, each cyclic delay module being configured to add a cyclic delay to a corresponding coded data stream that is mapped to one of the transmit antennas in order to simulate spatial diversity between the plurality of transmit antennas.
3. The physical layer module of claim 1, wherein the mapping module is configured to map the plurality of coded data streams to the plurality of transmit antennas in accordance with a mapping matrix.
4. The physical layer module of claim 3, wherein the mapping matrix is a unitary matrix.
5. The physical layer module of claim 1, wherein each complex gain comprises a corresponding amplitude gain and phase shift.
6. The physical layer module of claim 5, wherein the phase shifts associated with the plurality of gain modules are uniformly distributed over an interval of 2\u03c0 radians.
7. The physical layer module of claim 5, wherein the amplitude gains associated with the plurality of gain modules are uniformly distributed over an interval of 0,1.
8. The physical layer module of claim 1, further comprising:
a plurality of inverse fast-fourier transform modules,
wherein each inverse fast-fourier transform module
(i) is associated with a respective radio frequency channel of the plurality of radio frequency channels, and
(ii) is configured to transform the coded data stream associated with the respective radio frequency channel from a frequency domain to a time domain.
9. The physical layer module of claim 8, further comprising:
a plurality of cyclic prefix modules,
wherein each cyclic prefix module
(i) is associated with a respective radio frequency channel of the plurality of radio frequency channels, and
(ii) is configured to concatenate a cyclic prefix to a data packet, wherein the data packet is formed from the coded data stream associated with the respective radio frequency channel.
10. The physical layer module of claim 1, wherein the plurality of radio frequency channels corresponds to subchannels of an orthogonal frequency division multiplexing channel.
11. A wireless system comprising:
the physical layer module of claim 1; and
a media access controller in communication with the physical layer module.
12. The wireless system of claim 11, wherein the wireless system is a multi-input multi-output (MIMO) transmission station.
13. A method comprising
mapping a plurality of coded data streams to a plurality of transmit antennas, wherein each transmit antenna is associated with a respective radio frequency channel of a plurality of radio frequency channels;
generating a mapped output corresponding to each transmit antenna, wherein the mapped output corresponding to each transmit antenna includes a plurality of outputs, and wherein each of the outputs in the plurality of outputs is different; and
for each respective radio frequency channel,
applying a complex gain to each of the outputs included in the mapped output corresponding to the transmit antenna associated with the respective radio frequency channel,
wherein the complex gain applied to each of the outputs included in the mapped output corresponding to one of the transmit antennas differs from complex gains applied to each of the outputs included in mapped outputs corresponding to other transmit antennas.
14. The method of claim 13, further comprising adding a cyclic delay to each of the corresponding coded data streams that are mapped to a corresponding transmit antenna in order to simulate spatial diversity between the plurality of transmit antennas.
15. The method of claim 13, wherein mapping the plurality of coded data streams to the plurality of transmit antennas comprises using a mapping matrix.
16. The method of claim 15, wherein the mapping matrix is a unitary matrix.
17. The method of claim 13, wherein the plurality of radio frequency channels corresponds to subchannels of an orthogonal frequency division multiplexing channel.
18. A computer program tangibly stored on a non-transitory computer readable medium, the computer program being executable by a processor and comprising instructions for:
mapping a plurality of coded data streams to a plurality of transmit antennas, wherein each transmit antenna is associated with a respective radio frequency channel of a plurality of radio frequency channels;
generating a mapped output corresponding to each transmit antenna, wherein the mapped output corresponding to each transmit antenna includes a plurality of outputs, and wherein each of the outputs in the plurality of outputs is different; and
for each respective radio frequency channel,
applying a complex gain to each of the outputs included in the mapped output corresponding to the transmit antenna associated with the respective radio frequency channel,
wherein the complex gain applied to each of the outputs included in the mapped output corresponding to one of the transmit antennas differs from complex gains applied to each of the outputs included in mapped outputs corresponding to other transmit antennas.
19. The computer program of claim 18, wherein the plurality of radio frequency channels corresponds to subchannels of an orthogonal frequency division multiplexing channel.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. An optical amplifier, comprising:
an erbium doped optical fiber (EDF) amplifying section; and
a Raman amplifying section,
wherein the Raman amplifying section has a temperature dependent gain profile which enables compensating for temperature dependent changes in a gain profile of the EDF amplifying section.
2. An optical amplifier according to claim 1,
wherein the Raman amplifying section comprises a wavelength lock grating whose transmission wavelengths shift toward the short wavelength side as the temperature increases.
3. An optical amplifier according to claim 2,
wherein the wavelength lock grating is disposed to have the same temperature as that of an EDF included in the EDF amplifying section.
4. An optical amplifier according to claim 2,
wherein the wavelength lock grating is an optical fiber having a grating in which the refractive index of a core thereof varies at a predetermined period.
5. An optical amplifier according to claim 1, wherein the Raman amplifying section is disposed upstream with respect to the EDF amplifying section.
6. An optical amplifier according to claim 1, wherein the Raman amplifying section is disposed downstream with respect to the EDF amplifying section.
7. An optical amplifier according to claim 1, wherein the EDF amplifying section and a wavelength lock grating are accommodated in single body of equipment.
8. A method for compensating for temperature dependent gain flatness of an optical amplifier comprising:
providing an EDF amplifying section and a Raman amplifying section in the optical amplifier; and
setting the temperature dependent gain profile of the EDF amplifying section and the temperature dependent gain profile of the Raman amplifying section to compensate for each other when temperature changes.
9. A method according to claim 8, wherein the Raman amplifying section comprises a wavelength lock grating whose transmission wavelengths shift toward the short wavelength side as the temperature increases.
10. A method according to claim 9, wherein the method further comprises making the temperature of the wavelength lock grating the same as that of an EDF included in the EDF amplifying section.
11. An optical transmission path comprising:
a base transmission path including a signal transmission optical fiber and an EDF amplifying section for amplifying signal light passing through the signal transmission optical fiber; and
a Raman amplifying section, which includes an excitation light source for performing a Raman type amplification using the signal transmission optical fiber as an amplifying medium, and a wavelength lock grating that transmits excitation light having a predetermined wavelength to input the excitation light into the signal transmission optical fiber, wherein
transmission wavelengths of the wavelength lock grating shift toward the short wavelength side as the temperature increases.
12. An optical transmission path according to claim 11, wherein the excitation light source comprises a plurality of different light sources.
13. An optical transmission path according to claim 12, wherein the plurality of different light sources have at least two different wavelengths.
14. An optical transmission path according to claim 12, wherein the plurality of different light sources have at least two different polarization planes.