Method and apparatus for handling communications between spacecraft operating in an orbital environment and terrestrial telecommunications devices that use terrestrial base station communications
A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.
1. A multiple-access transceiver adapted for operation in Earth orbit and configured for communication with terrestrial mobile stations, comprising:
a data parser that parses data received by the multiple-access transceiver according to a frame structure, wherein the frame structure defines which timeslots are allocated to which terrestrial mobile stations;
a signal timing module that adjusts timing of transmitted signals based on orbit to terrestrial propagation delays; and
a programmable radio capable of communicating from the Earth orbit to a terrestrial mobile station that uses a protocol usable both for communication between the programmable radio and the terrestrial mobile station and for communication between a terrestrial cellular base station and the terrestrial mobile station.
2. The multiple-access transceiver of claim 1 , wherein the terrestrial mobile stations are cellular telephone handsets, smartphones, and connected mobile devices.
3. The multiple-access transceiver of claim 1 , further comprising signal allocation logic to allocate capacity of the multiple-access transceiver to a plurality of terrestrial mobile stations, including the terrestrial mobile station, distributed over a plurality of timeslots, a plurality of carrier frequencies, a plurality of orthogonal subcarriers and/or a plurality of code sequences.
4. The multiple-access transceiver of claim 1 , wherein the protocol is a multiple-access protocol used by the multiple-access transceiver to handle communications with a plurality of terrestrial mobile stations.
5. The multiple-access transceiver of claim 1 , wherein a plurality of timeslots are variably delayed in the frame structure to account for the multiple-access transceiver handling communications from a plurality of terrestrial mobile stations having a plurality of distances from the multiple-access transceiver by assigning each of a plurality of different distance ranges to each of a plurality of channel blocks.
6. The multiple-access transceiver of claim 5 , wherein the plurality of different distance ranges collectively cover a slant range from a zenith distance through a minimum elevation distance, wherein the zenith distance is a distance between a zenith position of a satellite carrying the multiple-access transceiver relative to a terrestrial mobile station and wherein the minimum elevation distance is a distance between a position of the satellite when the terrestrial mobile station enters a design footprint of the satellite.
7. The multiple-access transceiver of claim 6 , wherein the different distance ranges each span approximately 34 to 35 kilometers and a difference between the zenith distance and a low elevation distance is between 210 and 250 kilometers.
8. A multiple-access transceiver adapted for operation in Earth orbit and configured for communication with terrestrial mobile stations, comprising:
a data parser that parses data received by the multiple-access transceiver according to a frame structure, wherein the frame structure defines which timeslots are allocated to which terrestrial mobile stations;
a range calculator that determines, for each terrestrial mobile station, a distance from the multiple-access transceiver to the terrestrial mobile station;
a signal timing module that determines timing of transmitted signals relative to the frame structure, wherein the frame structure comprises a plurality of slots each having a zero or nonzero timeslot synchronization offset that provides for variable transmission delays that are due to the distance from the multiple-access transceiver to the terrestrial mobile station; and
an input signal allocator that allocates a listening timeslot in the frame structure to listen for communications from the terrestrial mobile station where the listening timeslot is timed based on the distance from the multiple-access transceiver to the terrestrial mobile station and the listening timeslot is one of a plurality of timeslots that are variably delayed in the frame structure to account for the multiple-access transceiver handling communications from a plurality of terrestrial mobile stations having a plurality of distances from the multiple-access transceiver.
9. The multiple-access transceiver of claim 8 , wherein the plurality of timeslots are variably delayed in the frame structure to account for the multiple-access transceiver handling communications from the plurality of terrestrial mobile stations having the plurality of distances from the multiple-access transceiver by assigning each of a plurality of different distance ranges to each of a plurality of channel blocks.
10. The multiple-access transceiver of claim 9 , wherein the plurality of different distance ranges collectively cover a slant range from a zenith distance through a minimum elevation distance, wherein the zenith distance is a distance between a zenith position of a satellite carrying the multiple-access transceiver relative to a terrestrial mobile station and wherein the minimum elevation distance is a distance between a position of the satellite when the terrestrial mobile station enters a design footprint of the satellite.
11. The multiple-access transceiver of claim 10 , wherein the different distance ranges each span approximately 34 to 35 kilometers and a difference between the zenith distance and a low elevation distance is between 210 and 250 kilometers.
12. The multiple-access transceiver of claim 9 , wherein a design footprint of a satellite is a circle, ellipse, or rectangle and is independent of, or a function of an antenna and/or antenna beam shape.
13. A multiple-access transceiver adapted for operation in Earth orbit and configured for communication with terrestrial mobile stations, comprising:
a data parser that parses data received by the multiple-access transceiver according to a frame structure, wherein the frame structure defines which timeslots are allocated to which terrestrial mobile stations;
a range calculator that determines, for each terrestrial mobile station, a distance from the multiple-access transceiver to the terrestrial mobile station;
a channel assignment module that assigns a plurality of terrestrial mobile stations to a plurality of channel blocks, wherein a channel block has a terrestrial frequency and an orbital frequency offset;
a signal timing module that determines timing of transmitted signals relative to the frame structure; and
a signal modulator that modulates signals to a terrestrial mobile station at the terrestrial frequency with the orbital frequency offset, wherein the orbital frequency offset at least approximately corresponds with an expected Doppler shift in signals transmitted to the terrestrial mobile station due to relative movement of the multiple-access transceiver and the terrestrial mobile station so that the terrestrial mobile station receives the signal at the terrestrial frequency.
14. The multiple-access transceiver of claim 13 , wherein the orbital frequency offset varies in 5 kilohertz increments.
15. The multiple-access transceiver of claim 13 , wherein a plurality of timeslots are variably delayed in the frame structure to account for the multiple-access transceiver handling communications from the plurality of terrestrial mobile stations having a plurality of distances from the multiple-access transceiver by assigning each of a plurality of different distance ranges to each of the plurality of channel blocks.
16. The multiple-access transceiver of claim 15 , wherein the plurality of different distance ranges collectively cover a slant range from a zenith distance through a minimum elevation distance, wherein the zenith distance is a distance between a zenith position of a satellite carrying the multiple-access transceiver relative to a terrestrial mobile station and wherein the minimum elevation distance is a distance between a position of the satellite when the terrestrial mobile station enters a design footprint of the satellite.
17. The multiple-access transceiver of claim 16 , wherein the different distance ranges each span approximately 34 to 35 kilometers and a difference between the zenith distance and a low elevation distance is between 210 and 250 kilometers.
18. A multiple-access transceiver adapted for operation in Earth orbit and configured for communication with terrestrial mobile stations, comprising:
a data parser that parses data received by the multiple-access transceiver according to a frame structure, wherein the frame structure defines which timeslots are allocated to which terrestrial mobile stations;
a range calculator that determines, for each terrestrial mobile station, a distance from the multiple-access transceiver to the terrestrial mobile station;
a channel assignment module that assigns a plurality of terrestrial mobile stations to a plurality of channel blocks, wherein a channel block has a terrestrial frequency and an orbital frequency offset;
a signal timing module that determines timing of transmitted signals relative to the frame structure; and
a signal modulator that modulates signals to a terrestrial mobile station at the terrestrial frequency with the orbital frequency offset, wherein the orbital frequency offset at least approximately corresponds with an expected Doppler shift in signals transmitted to the terrestrial mobile station due to relative movement of the multiple-access transceiver and the terrestrial mobile station so that the terrestrial mobile station receives the signal at the terrestrial frequency,
wherein the plurality of channel blocks are allocated based on relative positions of a satellite carrying the multiple-access transceiver and the terrestrial mobile station.
19. The multiple-access transceiver of claim 18 , wherein a plurality of timeslots are variably delayed in the frame structure to account for the multiple-access transceiver handling communications from the plurality of terrestrial mobile stations having a plurality of distances from the multiple-access transceiver by assigning each of a plurality of different distance ranges to each of the plurality of channel blocks.
20. The multiple-access transceiver of claim 19 , wherein the plurality of different distance ranges collectively cover a slant range from a zenith distance through a minimum elevation distance, wherein the zenith distance is a distance between a zenith position of the satellite carrying the multiple-access transceiver relative to a terrestrial mobile station and wherein the minimum elevation distance is a distance between a position of the satellite when the terrestrial mobile station enters a design footprint of the satellite.