Dual mode satellite/cellular terminal
A method and apparatus of communicating information using Time Division Multiple Access and adaptive transmission and reception are disclosed. Signal bursts are transmitted from TDMA transmitters to a TDMA receiver wherein the transmitter codes the information and transmits coded information to the receiver using at least one of two timeslots of a plurality of timeslots in a repetitive TDMA frame period. Both of the two timeslots are received whether or not the transmitter has transmitted using one or two timeslots and the received signals are classified as intended and non-intended. Successively received signals classified as intended are then assembled into a block for decoding to reproduce the information.
1. A dual mode transceiver comprising:
a linear modulation receiver adapted to receive linearly modulated TDMA signals from a first remote station over a first TDMA downlink channel having a given bandwidth, said linear modulation receiver being operative to receive constant envelope modulated TDMA signals from a second remote station over a second TDMA downlink channel having the same given channel bandwidth, wherein the constant envelope TDMA signals are an approximation of said linearly modulated TDMA signals, and wherein the first and second TDMA downlink channels have time slots of equal duration and include the same number of bits; and
a transmitter that transmits constant envelope modulated TDMA signals over an uplink channel to said first and second remote stations.
2. The dual mode transceiver of claim 1 wherein said first remote station is a satellite relay station.
3. The dual mode transceiver of claim 2 wherein said second remote station is a terrestrial base station.
4. The dual mode transceiver of claim 1 wherein said constant envelope modulated TDMA signals are Gaussian Minimum Shift Keyed (GMSK) modulated signals.
5. The dual mode transceiver of claim 1 wherein said linearly modulated TDMA signals are Offset Quadrature Phase Shift Keying (OQPSK) signals.
6. The dual mode transceiver of claim 1 wherein the frame period of the first TDMA downlink channel is longer than the period of the second TDMA downlink channel.
7. The dual mode transceiver of claim 6 wherein the linearly modulated TDMA signals are received in periodic time slots with a first spacing, and wherein said constant envelope modulated TDMA signals are received in periodic time slots with a second spacing less than said first spacing such that the average bit rate of the linearly modulated TDMA signals is less than the average bit rate of the constant envelope modulated TDMA signals.
8. A method of transmitting and receiving signals at a dual mode transceiver:
receiving linearly modulated TDMA signals from a first remote station over a first TDMA downlink channel having a given bandwidth with a linear modulation receiver configured to receive linearly modulated TDMA signals;
receiving constant envelope modulated TDMA signals form a second remote station over a second TDMA downlink channel having the same given bandwidth with said linear modulation receiver, wherein the constant envelope TDMA signals are an approximation of said linearly modulated TDMA signals, and wherein the first and second TDMA downlink channels have time slots of equal duration and include the same number of bits; and
transmitting constant envelope modulated TDMA signals to the first and second remote stations.
9. The method of claim 8 wherein said first remote station is a satellite relay station.
10. The method of claim 9 wherein said second remote station is a terrestrial base station.
11. The method of claim 8 wherein said constant envelope modulated TDMA signals are Gaussian Minimum Shift Keyed (GMSK) modulated signals.
12. The method of claim 8 wherein said linearly modulated TDMA signals are Offset Quadrature Phase Shift Keying (OQPSK) signals.
13. The method of claim 8 wherein the frame period of the first TDMA downlink channel is longer than the period of the second TDMA downlink channel.
14. The method of claim 13 wherein the linearly modulated TDMA signals are received in periodic time slots with a first spacing, and wherein said constant envelope modulated TDMA signals are received in periodic time slots with a second spacing less than said first spacing such that the average bit rate of the linearly modulated TDMA signals is less than the average bit rate of the constant envelope modulated TDMA signals.