CO-CHANNEL WIRELESS COMMUNICATION METHODS AND SYSTEMS USING RELAYED WIRELESS COMMUNICATIONS

• US 20080119190A1
• Filed: 01/29/2008
• Published: 05/22/2008
• Est. Priority Date: 03/24/2003
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: Mobile Satellite Venture LP
• Inventors: Karabinis, Peter
• Granted Patent: US 7,831,201 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/18584 Arrangements for data networking, i.e. for data packet routing, for congestion control data switching networks H04L12/00
• CPC Class Codes: H04W 52/38 TPC being performed in particular situations
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Wireless communications are transmitted from at least two radioterminals to a base station co-channel over a return link using a return link alphabet. Wireless communications are also transmitted from the base station to the at least two radioterminals over a forward link using a forward link alphabet that has more symbols than the return link alphabet. The co-channel signals are deciphered at the receiver, while the radioterminals can use a smaller return link alphabet, which can reduce the power dissipation at the radioterminals.

Claims

1. A wireless communication method comprising:

receiving wireless communications from a base station at a first radioterminal and at least one second radioterminal that is proximate the first radioterminal, over a forward link, co-channel;

relaying the wireless communications from the at least one second radioterminal to the first radioterminal over a short-range wireless link; and

using the wireless communications that are relayed to the first radioterminal from the at least one second radioterminal over the short-range wireless link to process the wireless communications that are received from the base station at the first radioterminal.

2. A wireless communication method according to claim 1:

wherein receiving wireless communications from a base station at a first radioterminal and at least one second radioterminal that is proximate to the first radioterminal, over a forward link, co-channel comprises receiving wireless communications from a base station at a first radioterminal and at least one second radioterminal that is proximate to the first radioterminal, over a forward link, co-channel using a forward link alphabet; and

wherein the method further comprises transmitting wireless communications from the first radioterminal and at least one second radioterminal to the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet.

3. A method according to claim 2 wherein transmitting wireless communications from the first radioterminal and at least one second radioterminal to the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet comprises:

transmitting wireless communications from the first radioterminal and at least one second radioterminal to at least one antenna at the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet.

4. A method according to claim 2 wherein transmitting wireless communications from the first radioterminal and at least one second radioterminal to the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet comprises:

transmitting wireless communications from the first radioterminal and at least one second radioterminal to a plurality of multiple-polarized antennas in a sector of the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet.

5. A method according to claim 2 wherein transmitting wireless communications from the first radioterminal and at least one second radioterminal to the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet comprises:

transmitting wireless communications from the first radioterminal and at least one second radioterminal to at least one multiple-polarized antenna in at least two sectors of the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet.

6. A method according to claim 2 wherein the base station is a first base station and wherein transmitting wireless communications from the first radioterminal and at least one second radioterminal to the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet comprises:

transmitting wireless communications from the first radioterminal and at least one second radioterminal to at least one multiple-polarized antenna at the first base station and at least one multiple-polarized antenna at a second base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet.

7. A method according to claim 4 wherein transmitting wireless communications from the first radioterminal and at least one second radioterminal to a plurality of multiple-polarized antennas in a sector of the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet comprises:

transmitting wireless communications from the first radioterminal and at least one second radioterminal to a plurality of multiple-polarized antennas in a sector of the base station co-channel using a return link alphabet that has fewer symbols than the forward link alphabet if the first radioterminal and the at least one second radioterminal are separated by more than a predetermined distance.

8. A method according to claim 1, wherein receiving wireless communications from a base station at a first radioterminal and at least one second radioterminal that is proximate to the first radioterminal, over a forward link, co-channel, comprises:

receiving wireless communications signals that overlap in time and space, and that use the same carrier frequency, the same time slot if the signals are Time Division Multiple Access (TDMA) signals, and the same spreading code if the signals are Code Division Multiple Access (CDMA) signals, such that the wireless communication signals collide at each of the first and second radioterminals.

9. A radioterminal comprising:

a transmitter that is configured to transmit wireless communications to a base station; and

a receiver that is configured to receive at least first and second signals, to process the at least first and second signals to derive first data that is associated with information transmitted by the base station to at least one device other than the radioterminal and to use the first data to derive second data that is associated with information transmitted by the base station to the radioterminal.

10. A radioterminal according to claim 9 wherein the receiver is configured to receive the at least first and second signals using at least one antenna.

11. A radioterminal according to claim 10 wherein the at least one antenna comprises at least one multiple-polarized antenna and/or a plurality of spaced-apart antennas.

12. A radioterminal according to claim 11 wherein the at least one multiple polarized antenna comprises a plurality of multiple-polarized antennas.

13. A radioterminal according to claim 9, wherein the receiver is configured to receive wireless communication signals that overlap in time and space, and that use the same carrier frequency, the same time slot if the signals are Time Division Multiple Access (TDMA) signals, and the same spreading code if the signals are Code Division Multiple Access (CDMA) signals, such that the wireless communication signals collide at the receiver.

14. A radioterminal according to claim 9 wherein the receiver is further configured to decode at least one of the first and second signals.

15. A radioterminal according to claim 14, wherein configured to decode comprises configured to:

derive at least first and second decision variables;

associate with each one of the at least first and second decision variables a measure of noise and/or interference;

select at least one of the at least first and second decision variables responsive to at least one noise and/or interference content associated therewith;

make at least one first decision based upon the selected at least one decision variable; and

use the at least one first decision to make a second decision.

16. A radioterminal according to claim 14, wherein configured to decode comprises configured to:

generate a delayed version of the at least first and second signals; and

jointly process the at least first and second signals and the delayed version of the at least first and second signals.

17. A radioterminal according to claim 16, wherein configured to jointly process comprises using a linear and/or non-linear processor.

18. A radioterminal according to claim 17, wherein the linear and/or non-linear processor comprises a Least Mean Squared Error (LMSE), Kalman-based, least squares, recursive least squares, Zero Forcing (ZF) and/or Maximum Likelihood Sequence Estimation (MLSE) processor.

19. A radioterminal according to claim 18, wherein configured to jointly process comprises configured to cancel Co-Channel Interference (CCI).

20. A radioterminal comprising:

a receiver that is configured to receive wireless communications from a base station over a forward link, to receive wireless communications from at least one second radioterminal over a short-range wireless link, and to use the wireless communications that are received from the at least one second radioterminal over the short-range wireless link to process the wireless communications that are received from the base station.

21. A radioterminal according to claim 20:

wherein the receiver is configured to receive wireless communications from the base station over a forward link using a forward link alphabet; and

wherein the radioterminal further comprises a transmitter that is configured to transmit wireless communications to the base station using a return link alphabet that has fewer symbols than the forward link alphabet.

22. A radioterminal according to claim 20, wherein the receiver is further configured to process the wireless communications that are received from the base station and the wireless communications that are received from the at least one second radioterminal to derive first data that is not intended for the radioterminal and to use the first data to derive second data that is intended for the radioterminal.

23. A radioterminal according to claim 22, wherein further configured to process comprises further configured to:

derive at least first and second decision variables;

associate with each one of the at least first and second decision variables a measure of noise and/or interference;

select at least one of the at least first and second decision variables responsive to at least one noise and/or interference content associated therewith;

make at least one first decision based upon the selected at least one decision variable; and

use the at least one first decision to make a second decision.

24. A radioterminal according to claim 22, wherein further configured to process comprises further configured to:

receive at least first and second signals;

generate a delayed version of at least first and second signals; and

jointly process the at least first and second signals and the delayed version of the at least first and second signals.

25. A radioterminal according to claim 24, wherein configured to jointly process comprises using a linear and/or non-linear processor.

26. A radioterminal according to claim 25, wherein the linear and/or non-linear processor comprises a Least Mean Squared Error (LMSE), Kalman-based, least squares, recursive least squares, Zero Forcing (ZF) and/or Maximum Likelihood Sequence Estimation (MLSE) processor.