FREQUENCY DIVISION DUPLEX (FDD) RETURN LINK TRANSMIT DIVERSITY SYSTEMS, METHODS AND DEVICES USING FORWARD LINK SIDE INFORMATION

• US 20110103273A1
• Filed: 03/09/2010
• Published: 05/05/2011
• Est. Priority Date: 11/04/2009
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Dutta, Santanu
• Granted Patent: US 10,110,288 B2
• Time in Patent Office: Days
• US Class Current: 370/281
• CPC Class Codes: H04B 7/0604 with predefined switching scheme
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0871 using different reception schemes, at least one of them being a diversity reception scheme
• CPC Class Codes: H04B 7/0877 switching off a diversity branch, e.g. to save power

Abstract

A Frequency Division Duplex (FDD) wireless terminal includes spaced-apart antennas that are configured to transmit over a return link and to receive over a forward link that is spaced apart from the return link in frequency. The FDD wireless terminal is configured to selectively refrain from transmitting over the return link from at least one of the spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the spaced-apart antennas of the FDD wireless terminal, that are caused, for example, by blocking appendages of a user of the wireless terminal. Related methods are also described.

Claims

1. A transmit diversity method for a Frequency Division Duplex (FDD) wireless terminal, the FDD wireless terminal comprising a plurality of spaced-apart antennas that are configured to transmit over a return link and to receive over a forward link that is spaced apart from the return link in frequency, the transmit diversity method comprising:

selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal.

2. A method according to claim 1 wherein the channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises measuring forward link power at the plurality of spaced-apart antennas of the FDD wireless terminal over an averaging period.

3. A method according to claim 2 wherein the averaging period is configured by a wireless network and transmitted to the FDD wireless terminal and/or is configured by the FDD wireless terminal.

4. A method according to claim 1 wherein the channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal.

5. A method according to claim 1 wherein the channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal that are caused by appendages of a user of the FDD wireless terminal.

6. A method according to claim 4 wherein estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal comprises estimating differential gains of the plurality of spaced-apart antennas of the FDD wireless terminal, averaged over angles of arrival of the forward link.

7. A method according to claim 4 wherein estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal comprises determining blockage levels at the plurality of spaced-apart antennas of the FDD wireless terminal relative to a threshold blockage level.

8. A method according to claim 7 wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal comprises selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal that has a blockage level that is greater than the threshold blockage level.

9. A method according to claim 7 wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal comprises determining that all of the plurality of spaced-apart antennas of the FDD wireless terminal have blockage levels greater than the threshold blockage level and wherein the method further comprises transmitting over an antenna of the FDD wireless terminal having lowest blockage level.

10. A method according to claim 7 wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal comprises determining that only one of the antennas of the FDD wireless terminal has a blockage level less than the threshold blockage level and wherein the method further comprises transmitting over only the one antenna of the FDD wireless terminal.

11. A method according to claim 7 wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal comprises determining that two or more of the antennas of the FDD wireless terminal have blockage levels less than the threshold blockage level and wherein the method further comprises alternately transmitting over the two or more antennas of the FDD wireless terminal.

12. A transmit diversity method for a Frequency Division Duplex (FDD) wireless terminal, the FDD wireless terminal comprising a plurality of spaced-apart antennas that are configured to transmit over a return link and to receive over a forward link that is spaced apart from the return link in frequency, the transmit diversity method comprising:

selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal.

13. A method according to claim 12 wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas that are caused by blocking appendages of a user of the FDD wireless terminal.

14. A method according to claim 12 wherein the plurality of antennas of the FDD wireless terminal consists of two antennas of the FDD wireless terminal, and wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises:

alternating transmitting between the two antennas of the FDD wireless terminal over the return link in response to differentials in forward link power that is received at the two antennas of the FDD wireless terminal being less than a threshold; and

refraining from transmitting over the return link from one of the two antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the two antennas of the FDD wireless terminal exceeding the threshold.

15. A method according to claim 12 wherein the plurality of antennas of the FDD wireless terminal comprises three or more antennas of the FDD wireless terminal, and wherein selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises:

alternating transmitting between at least two of the antennas of the FDD wireless terminal over the return link in response to the forward link power that is received at the at least two antennas of the FDD wireless terminal exceeding a threshold;

transmitting from only one antenna of the FDD wireless terminal over the return link in response to the forward link power that is received at the only one antenna of the FDD wireless terminal exceeding the threshold; and

/or

transmitting from only one of the antennas of the FDD wireless terminal having a highest forward link power in response to the forward link power that is received at all of the antennas of the FDD wireless terminal being less than the threshold.

16. A Frequency Division Duplex (FDD) wireless terminal, comprising:

a plurality of spaced-apart antennas;

a transmitter that is configured to transmit over a return link from the plurality of spaced-apart antennas of the FDD wireless terminal;

a receiver that is configured to receive over a forward link that is spaced apart from the return link in frequency, from the plurality of spaced-apart antennas of the FDD wireless terminal; and

a processor that is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal.

17. An FDD wireless terminal according to claim 16 wherein the channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises measuring forward link power at the plurality of spaced-apart antennas of the FDD wireless terminal over an averaging period.

18. An FDD wireless terminal according to claim 17 wherein the averaging period is configured by a wireless network and transmitted to the FDD wireless terminal and/or is configured by the FDD wireless terminal.

19. An FDD wireless terminal according to claim 17 wherein the channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal.

20. An FDD wireless terminal according to claim 17 wherein the channel estimating of the forward link that is received at the plurality of spaced-apart antennas of the FDD wireless terminal comprises estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal that are caused by appendages of a user of the FDD wireless terminal.

21. An FDD wireless terminal according to claim 19 wherein estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal comprises estimating differential gains of the plurality of spaced-apart antennas of the FDD wireless terminal, averaged over angles of arrival of the forward link.

22. An FDD wireless terminal according to claim 19 wherein estimating differential blockages of the forward link at the plurality of spaced-apart antennas of the FDD wireless terminal comprises determining blockage levels at the plurality of spaced-apart antennas of the FDD wireless terminal relative to a threshold blockage level.

23. An FDD wireless terminal according to claim 22 wherein the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal by controlling the transmitter of perform operations comprising selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal that has a blockage level that is greater than the threshold blockage level.

24. An FDD wireless terminal according to claim 22 wherein the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal by controlling the transmitter of perform operations comprising determining that all of the plurality of spaced-apart antennas of the FDD wireless terminal have blockage levels greater than the threshold blockage level and wherein the method further comprises transmitting over an antenna of the FDD wireless terminal having lowest blockage level.

25. An FDD wireless terminal according to claim 22 wherein the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal by controlling the transmitter of perform operations comprising determining that only one of the antennas of the FDD wireless terminal has blockage level less than the threshold blockage level and wherein the method further comprises transmitting over only the one antenna of the FDD wireless terminal.

26. An FDD wireless terminal according to claim 22 wherein selectively the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal by controlling the transmitter of perform operations comprising determining that two or more of the antennas of the FDD wireless terminal have blockage levels less than the threshold blockage level and wherein the method further comprises alternately transmitting over the two or more antennas of the FDD wireless terminal.

27. A Frequency Division Duplex (FDD) wireless terminal, comprising:

a plurality of spaced-apart antennas;

a transmitter that is configured to transmit over a return link from the plurality of spaced-apart antennas of the FDD wireless terminal;

a receiver that is configured to receive over a forward link that is spaced apart from the return link in frequency, from the plurality of spaced-apart antennas of the FDD wireless terminal; and

a processor that is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal.

28. An FDD wireless terminal according to claim 27 wherein the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal by selectively refraining from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas that are caused by blocking appendages of a user of the FDD wireless terminal.

29. An FDD wireless terminal according to claim 27 wherein the plurality of antennas of the FDD wireless terminal consists of two antennas of the FDD wireless terminal, and wherein the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal by performing operations comprising:

alternating transmitting between the two antennas of the FDD wireless terminal over the return link in response to differentials in forward link power that is received at the two antennas of the FDD wireless terminal being less than a threshold; and

refraining from transmitting over the return link from one of the two antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the two antennas of the FDD wireless terminal exceeding the threshold.

30. An FDD wireless terminal according to claim 27 wherein the plurality of antennas of the FDD wireless terminal comprises three or more antennas of the FDD wireless terminal, and wherein the processor is configured to control the transmitter to selectively refrain from transmitting over the return link from at least one of the plurality of spaced-apart antennas of the FDD wireless terminal in response to differentials in forward link power that is received at the plurality of spaced-apart antennas of the FDD wireless terminal by performing operations comprising:

alternating transmitting between at least two of the antennas of the FDD wireless terminal over the return link in response to the forward link power that is received at the at least two antennas of the FDD wireless terminal exceeding a threshold;

transmitting from only one antenna of the FDD wireless terminal over the return link in response to the forward link power that is received at the only one antenna of the FDD wireless terminal exceeding the threshold; and

/or

transmitting from only one of the antennas of the FDD wireless terminal having a highest forward link power in response to the forward link power that is received at all of the antennas of the FDD wireless terminal being less than the threshold.