초록 ▼

A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signatur

A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signature-length than the signatures in other sets. The different signature-lengths can be optimized for the operational environments involved (e.g., longer signatures for slower-moving mobile stations, and shorter signatures for high-speed mobile stations). Alternatively, at least one differentially-encoded signature is used for random access transmissions, in order to reduce the radio channel's sensitivity to large doppler spreads and frequency errors.

대표청구항 ▼

A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signatur

A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signature-length than the signatures in other sets. The different signature-lengths can be optimized for the operational environments involved (e.g., longer signatures for slower-moving mobile stations, and shorter signatures for high-speed mobile stations). Alternatively, at least one differentially-encoded signature is used for random access transmissions, in order to reduce the radio channel's sensitivity to large doppler spreads and frequency errors. the first reflective coating (a) comprises a reflective coating with a reflectivity of approximately 100%. 9. The light source of claim 7, wherein the second reflective coating (b) comprises a reflective coating with a reflectivity of approximately 18%. 10. The light source of claim 7, wherein the phase bias element (c) is a λ/8 waveplate. 11. The light source of claim 6, wherein the introducing means comprises a phase bias element residing inside the space. 12. The light source of claim 11, wherein the phase bias element is a 8/4 waveplate. 13. The light source of claim 6, wherein the introducing means comprises: a reflective coating residing inside the space and on the first glass plate; a first waveplate with a first optical retardance residing inside the space; and a second waveplate with a second optical retardance, optically coupled to the first glass plate and residing outside the space, wherein a combination of values for the first reflectivity, the first optical retardance, and the second optical retardance effects a separation of channels in at least one optical signal into at least two sets, wherein the at least two sets have asymmetrically interleaved pass bands. 14. A light source for an optical network, comprising: an output optical fiber; a semiconductor optical gain element optically coupled to the output optical fiber, creating a main axis, the semiconductor optical gain element comprising a front facet and a rear facet; a polarization beam splitter optically coupled to the rear facet of the semiconductor optical gain element and intersecting the main axis; and two non-linear interferometers optically coupled to the polarization beam splitter, a first of the non-linear interferometers optically coupled to a first side of the polarization beam splitter furthest from semiconductor optical gain element, the first non-linear interferometer being perpendicular to and intersecting the main axis, and a second of the non-linear interferometers optically coupled to a second side of the polarization beam splitter perpendicular to the first face, the second non-linear interferometer being parallel to the main axis. 15. The light source of claim 14, wherein the front facet comprises a high-reflectivity coating or no coating. 16. The light source of claim 14, wherein the rear facet comprises an anti-reflectivity coating. 17. The light source of claim 14, further comprising: a first aspheric lens optically coupled to the rear facet and the polarization beam splitter; a second aspheric lens optically coupled to the front facet; a focusing lens optically coupled to the second aspheric lens; and an optical fiber optically coupled to the focusing lens. 18. The light source of claim 14, wherein the polarization beam splitter comprises anti-reflectivity coatings on faces adjacent to and across from each of the two non-linear interferometers. 19. The light source of claim 14, wherein each of the non-linear interferometers comprises: a first glass plate optically coupled to a second glass plate, forming a space therebetween; means for introducing a polarization rotation in at least one channel of an optical signal; and means for broadening a bandwidth of a rotated band of the optical signal. 20. The light source of claim 19, wherein the broadening means comprises: (a) a first reflective coating residing inside the space and on the second glass plate; (b) a second reflective coating residing inside the space and on the first glass plate; and (c) a phase bias element residing outside the space. 21. The light source of claim 20, wherein the first reflective coating (a) comprises a reflective coating with a reflectivity of approximately 100%. 22. The light source of claim 20, wherein the second reflective coating (b) comprises a reflective coating with a reflectivity of approximately 18%. 23. The light source of claim 20, wherein the phase bias element (c) is a λ/8 waveplate. 24. The light sou