Single User Multiple Input Multiple Output User Equipment

• US 20100173640A1
• Filed: 01/06/2010
• Published: 07/08/2010
• Est. Priority Date: 01/06/2009
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation, Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Pajukoski, Kari, Tiirola, Esa, Roman, Timo, Hooli, Kari, Koivisto, Tommi
• Granted Patent: US 8,423,037 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04B 7/0404 the mobile station comprising multiple antennas, e.g. to provide uplink diversity
• CPC Class Codes: H04B 7/0434 using multiple eigenmodes
• CPC Class Codes: H04B 7/0465 taking power constraints at power amplifier or emission constraints, e.g. constant modulus, into account
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas

Abstract

In accordance with the exemplary embodiments of the invention there is at least a method, apparatus, and a computer program to perform operations including receiving information descriptive of a type of radio access which a user equipment is acting on, and in response to receiving the information descriptive of a particular type of radio access, transmitting from a multiple transmit antenna user equipment so that the transmission appears, at a receiver, to have been made by a single antenna user equipment, or by a user equipment that supports antenna switching/selection.

Claims

1. A method comprising:

receiving information descriptive of a type of radio access which a user equipment is acting on; and

in response to receiving the information descriptive of a particular type of radio access, transmitting from a multiple transmit antenna user equipment so that the transmission appears, at a receiver, to have been made by a single antenna user equipment, or by a user equipment that supports antenna switching/selection.

2. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink control channel, or on a frequency hopping physical uplink shared channel, and where the transmitting further comprises selecting one of the multiple transmit antennas to transmit during a first slot at a first frequency, and another one of the multiple transmit antennas to transmit during a second slot at a second frequency.

3. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink control channel, or on a frequency hopping physical uplink shared channel, and where the transmitting further comprises partitioning the multiple transmit antennas into at least two groups of transmit antennas, each group having at least two transmit antennas, and selecting one of the groups of transmit antennas to transmit during a first slot at a first frequency, and another one of the groups of transmit antennas to transmit during a second slot at a second frequency.

4. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink control channel, or on a frequency hopping physical uplink shared channel, and where the transmitting further comprises selecting a first precoding vector for the multiple transmit antennas for transmitting during a first slot at a first frequency, and selecting a second precoding vector for the multiple transmit antennas for transmitting during a second slot at a second frequency.

5. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises selecting at least two transmit antennas or at least two groups of transmit antennas and using the selected antennas or antenna groups in accordance with instructions received from a base station such that the user equipment appears to the base station as supporting transmit antenna selection.

6. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises selecting a first precoding vector for the multiple transmit antennas and selecting a second precoding vector for the multiple transmit antennas and using the selected first and second precoding vectors in accordance with instructions received from a base station such that the user equipment appears to the base station as supporting transmit antenna selection.

7. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, and where the transmitting further comprises selecting a single one of the multiple transmit antennas for transmitting to a base station such that the user equipment appears to the base station as having a single transmit antenna.

8. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises, a time division duplex case, deriving a precoding vector from a downlink channel estimate, and using the derived channel vector for transmitting on a single one of the multiple transmit antennas to a base station such that the user equipment appears to the base station as having a single transmit antenna.

9. The method according to claim 1, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises cyclically delaying signals from different ones of the multiple transmit antennas, relative to a first transmit antenna, by an antenna specific delay such that the user equipment appears to the base station as having a single transmit antenna.

10. The method according to claim 9, where the antenna specific delay determined such that the delay does not reduce coherence bandwidth of the resulting signal, when the signals from the multiple transmit antennas are combined, below a typical channel coherence bandwidth, and such that a delay spread of the transmitted signal is increased by an acceptable amount when compared to a cyclic prefix length.

11. The method according to claim 1, further comprising rotating signals to individual ones of the multiple transmit antennas with an antenna-specific phase rotation, where a change in the rotation rate and sign is selected such that a coherence time/time correlation of the resulting signal, when the signals from the multiple transmit antennas are combined, corresponds to a coherence time/time correlation that would be received from a user terminal moving at a low velocity.

12. The method according to claim 1 performed by software embodied on a memory and executed by at least one data processor.

13. An apparatus comprising:

at least one processor; and

at least one memory including computer program code, where the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least;

receive information descriptive of a type of radio access which a user equipment is acting on; and

in response to receiving the information descriptive of a particular type of radio access, transmit from a multiple transmit antenna user equipment so that the transmission appears, at a receiver, to have been made by a single antenna user equipment, or by a user equipment that supports antenna switching/selection.

14. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink control channel, or on a frequency hopping physical uplink shared channel, and where the transmitting further comprises selecting one of the multiple transmit antennas to transmit during a first slot at a first frequency, and another one of the multiple transmit antennas to transmit during a second slot at a second frequency.

15. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink control channel, or on a frequency hopping physical uplink shared channel, and where the transmitting further comprises partitioning the multiple transmit antennas into at least two groups of transmit antennas, each group having at least two transmit antennas, and selecting one of the groups of transmit antennas to transmit during a first slot at a first frequency, and another one of the groups of transmit antennas to transmit during a second slot at a second frequency.

16. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink control channel, or on a frequency hopping physical uplink shared channel, and where the transmitting further comprises selecting a first precoding vector for the multiple transmit antennas for transmitting during a first slot at a first frequency, and selecting a second precoding vector for the multiple transmit antennas for transmitting during a second slot at a second frequency.

17. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises selecting at least two transmit antennas or at least two groups of transmit antennas and using the selected antennas or antenna groups in accordance with instructions received from a base station such that the user equipment appears to the base station as supporting transmit antenna selection.

18. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises selecting a first precoding vector for the multiple transmit antennas and selecting a second precoding vector for the multiple transmit antennas and using the selected first and second precoding vectors in accordance with instructions received from a base station such that the user equipment appears to the base station as supporting transmit antenna selection.

19. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access and where the transmitting further comprises selecting a single one of the multiple transmit antennas for transmitting to a base station such that the user equipment appears to the base station as having a single transmit antenna.

20. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises, a time division duplex case, deriving a precoding vector from a downlink channel estimate, and using the derived channel vector for transmitting on a single one of the multiple transmit antennas to a base station such that the user equipment appears to the base station as having a single transmit antenna.

21. The apparatus according to claim 13, where the particular type of radio access is a Rel-8/9 LTE type radio access, where the transmission is made on a physical uplink shared channel, and where the transmitting further comprises cyclically delaying signals from different ones of the multiple transmit antennas, relative to a first transmit antenna, by an antenna specific delay such that the user equipment appears to the base station as having a single transmit antenna.

22. The apparatus according to claim 21, where the antenna specific delay determined such that the delay does not reduce coherence bandwidth of the resulting signal, when the signals from the multiple transmit antennas are combined, below a typical channel coherence bandwidth, and such that a delay spread of the transmitted signal is increased by an acceptable amount when compared to a cyclic prefix length.

23. The apparatus according to claim 13, further comprising rotating signals to individual ones of the multiple transmit antennas with an antenna-specific phase rotation, where a change in the rotation rate and sign is selected such that a coherence time/time correlation of the resulting signal, when the signals from the multiple transmit antennas are combined, corresponds to a coherence time/time correlation that would be received from a user terminal moving at a low velocity.