Method and Apparatus for Uplink Multi-Carrier Transmit Diversity

• US 20120002630A1
• Filed: 10/12/2010
• Published: 01/05/2012
• Est. Priority Date: 10/12/2009
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bergman, Johan, Hultell, Johan, Larsson, Erik, Johansson, Niklas
• Granted Patent: US 9,584,208 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0621 Feedback content
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 5/003 Arrangements for allocating sub-channels of the transmission path

Abstract

A method (400) and apparatus (300) for selecting one of a plurality of antennas (320, 322), on a UE (300) implementing transmit diversity in a multi-carrier wireless communication system, for the joint transmission of two or more uplink signals, each modulated onto a different carrier frequency, such as when the carriers share a power amplifier (314). The method (400) and apparatus (300) select an antenna (320, 322) based on channel conditions associated with the carriers, even when prior art transmit diversity methods provide conflicting antenna selection indications.

Claims

1. A method of antenna selection by User Equipment, UE, implementing transmit diversity in a Multiple Carrier High Speed Uplink Packet Access, MC-HSUPA, wireless communication network, the UE operative to transmit two or more uplink signals using one antenna, each signal modulated onto a different carrier frequency, wherein the method comprises, for the carrier frequencies to be transmitted using the same antenna:

associating a preferred antenna with each carrier frequency based on feedback received for that carrier when transmitting a signal using a particular antenna;

assessing the channel conditions associated with each carrier frequency;

selecting one or more carrier frequencies based on the channel conditions; and

selecting the preferred antenna associated with the selected carrier frequency.

2. The method of claim 1 wherein the feedback for a carrier when transmitting a signal using a particular antenna comprises Transmission Power Control, TPC, commands.

3. The method of claim 1 wherein assessing the channel conditions associated with each carrier frequency comprises assessing one or more quality metrics associated with each carrier frequency.

4. The method of claim 3 wherein the quality metric comprises the value of a serving grant.

5. The method of claim 3 wherein the quality metric comprises the value of a scheduled grant.

6. The method of claim 3 wherein the quality metric comprises the total transmit power the UE utilizes on the respective carrier.

7. The method of claim 3 wherein selecting one or more carrier frequencies based on the channel conditions comprises selecting the single carrier frequency having the most favorable associated channel conditions, of all the carrier frequencies to be transmitted using the selected antenna.

8. The method of claim 7 wherein selecting the single carrier frequency having the most favorable associated channel conditions comprises selecting the carrier frequency with the highest serving grant.

9. The method of claim 8 wherein selecting the single carrier frequency having the most favorable associated channel conditions further comprises selecting the carrier frequency based on received Transmission Power Control, TPC, commands corresponding to the carrier with the highest serving grant.

10. The method of claim 3 wherein selecting one or more carrier frequencies based on the channel conditions comprises forming a weighted sum of channel conditions for all carrier frequencies to be transmitted on a selected antenna, and wherein selecting an antenna comprises selecting the preferred antenna associated with the most heavily weighted carrier frequency.

11. The method of claim 10 wherein forming a weighted sum of channel conditions comprises summing, for all carrier frequencies to be transmitted on the selected antenna, first channel quality metrics, each weighted by the ratio of a second channel quality metric for a carrier frequency to the sum of the second channel quality metrics for all the carrier frequencies.

12. The method of claim 11 wherein forming a weighted sum of channel conditions comprises weighting Transmission Power Control, TPC, commands received for each carrier frequency by the ratio of the serving grant for that carrier frequency to the sum of serving grants for all carrier frequencies to be transmitted on the selected antenna.

13. The method of claim 11 wherein forming a weighted sum of channel conditions further comprises weighting each carrier frequency with a predetermined factor.

14. The method of claim 13 wherein a primary uplink carrier frequency is weighted more heavily than a secondary uplink carrier frequency.

15. The method of claim 3 wherein selecting one or more carrier frequencies based on the channel conditions comprises selecting one or more carrier frequencies for which channel quality metrics exceed one or more predetermined thresholds.

16. The method of claim 15 wherein the threshold for each carrier frequency is the value of a channel quality metric for that carrier frequency divided by the maximum value of the corresponding channel quality metrics for all other carrier frequencies to be transmitted using the selected antenna.

17. The method of claim 15 wherein the predetermined threshold for each carrier frequency is configured by the network.

18. The method of claim 17 wherein the predetermined threshold for each carrier frequency is configured by a Radio Network Controller, RNC, network node via L3 signaling.

19. The method of claim 17 wherein the predetermined thresholds for the carrier frequencies are such that only one predetermined carrier frequency is selected.

20. The method of claim 1 wherein selecting one or more carrier frequencies based on the channel conditions comprises selecting one or more carrier frequencies based on rules defined in an industry standard.

21. The method of claim 1 wherein selecting one or more carrier frequencies based on the channel conditions comprises selecting one or more carrier frequencies based on rules defined by the UE'"'"'s serving node and transmitted to the UE via L1/L2 signaling.

22. The method of claim 1 wherein selecting one or more carrier frequencies based on the channel conditions comprises selecting one or more carrier frequencies based on rules defined by a network node and transmitted to the UE via L3 signaling.

23. User Equipment, UE, implementing transmit diversity in a Multiple Carrier High Speed Uplink Packet Access, MC-HSUPA, wireless communication network, the UE operative to transmit two or more uplink signals using one antenna, each signal modulated onto a different carrier frequency, comprising:

at least one transmission power amplifier;

two or more antennas;

a switching function operative to direct the output of the power amplifier alternatively to one of the antennas;

a receiver operative to receive at least channel condition feedback from the network; and

an antenna selection function operative to control the switching function to select an antenna for the transmission of two or more signals on different carrier frequencies, the antenna selection function further operative to;

associate a preferred antenna with each carrier frequency based on feedback received for that carrier when transmitting a signal using a particular antenna;

assess the channel conditions associated with each carrier frequency;

select one or more carrier frequencies based on the channel conditions; and

select the preferred antenna associated with the selected carrier frequency.

24. The UE of claim 23 wherein the feedback for a carrier when transmitting a signal using a particular antenna comprises Transmission Power Control, TPC, commands.

25. The UE of claim 23 wherein the antenna selection function is operative to assess the channel conditions associated with each carrier frequency by assessing one or more quality metrics associated with each carrier frequency.

26. The UE of claim 25 wherein the quality metric comprises the value of a serving grant.

27. The UE of claim 25 wherein the quality metric comprises the value of a scheduled grant.

28. The UE of claim 25 wherein the quality metric comprises the total transmit power the UE utilizes on the respective carrier.

29. The UE of claim 25 wherein the antenna selection function is operative to select one or more carrier frequencies based on the channel conditions by selecting the single carrier frequency having the most favorable associated channel conditions, of all the carrier frequencies to be transmitted using the selected antenna.

30. The UE of claim 29 wherein selecting the single carrier frequency having the most favorable associated channel conditions comprises selecting the carrier frequency with the highest serving grant.

31. The UE of claim 30 wherein selecting the single carrier frequency having the most favorable associated channel conditions further comprises selecting the carrier frequency based on received Transmission Power Control, TPC, commands corresponding to the carrier with the highest serving grant.

32. The UE of claim 25 wherein the antenna selection function is operative to select one or more carrier frequencies based on the channel conditions by forming a weighted sum of channel conditions for all carrier frequencies to be transmitted on a selected antenna, and wherein the antenna selection function is operative to select an antenna by selecting the preferred antenna associated with the most heavily weighted carrier frequency.

33. The UE of claim 32 wherein forming a weighted sum of channel conditions comprises summing, for all carrier frequencies to be transmitted on the selected antenna, first channel quality metrics, each weighted by the ratio of a second channel quality metric for a carrier frequency to the sum of the second channel quality metrics for all the carrier frequencies.

34. The UE of claim 33 wherein forming a weighted sum of channel conditions comprises weighting Transmission Power Control, TPC, commands received for each carrier frequency by the ratio of the serving grant for that carrier frequency to the sum of serving grants for all carrier frequencies to be transmitted on the selected antenna.

35. The UE of claim 33 wherein forming a weighted sum of channel conditions further comprises weighting each carrier frequency with a predetermined factor.

36. The UE of claim 35 wherein a primary uplink carrier frequency is weighted more heavily than a secondary uplink carrier frequency.

37. The UE of claim 25 wherein the antenna selection function is operative to select one or more carrier frequencies based on the channel conditions by selecting one or more carrier frequencies for which channel quality metrics exceed one or more predetermined thresholds.

38. The UE of claim 37 wherein the threshold for each carrier frequency is the value of a channel quality metric for that carrier frequency divided by the maximum value of the corresponding channel quality metrics for all other carrier frequencies to be transmitted using the selected antenna.

39. The UE of claim 37 wherein the predetermined threshold for each carrier frequency is configured by the network.

40. The UE of claim 39 wherein the predetermined threshold for each carrier frequency is configured by a Radio Network Controller, RNC, network node via L3 signaling.

41. The UE of claim 39 wherein the predetermined thresholds for the carrier frequencies are such that only one predetermined carrier frequency is selected.

42. The UE of claim 23 wherein the antenna selection function is operative to select one or more carrier frequencies based on the channel conditions by selecting one or more carrier frequencies based on rules defined in an industry standard.

43. The UE of claim 23 wherein the antenna selection function is operative to select one or more carrier frequencies based on the channel conditions by selecting one or more carrier frequencies based on rules defined by the UE'"'"'s serving node and transmitted to the UE via L1/L2 signaling.

44. The UE of claim 23 wherein the antenna selection function is operative to select one or more carrier frequencies based on the channel conditions by selecting one or more carrier frequencies based on rules defined by a network node and transmitted to the UE via L3 signaling.