UPLINK SOUNDING REFERENCE SIGNALS CONFIGURATION AND TRANSMISSION

• US 20110268028A1
• Filed: 04/01/2011
• Published: 11/03/2011
• Est. Priority Date: 04/02/2010
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Shin, Sung-Hyuk, Dick, Stephen G., Wang, Peter S., Stern-Berkowitz, Janet A., Koo, Chang-Soo, Haim, John W., Beluri, Mihaela C.
• Granted Patent: US 9,749,968 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels

Abstract

Methods and apparatus for sounding reference signals (SRS) configuration and transmission. The methods include receiving configuration of wireless transmit/receive unit (WTRU)-specific SRS subframes for transmitting SRS and upon receipt of a trigger, transmitting the SRS for a number of antennas. The SRS transmissions may occur in each subframe of a duration of WTRU-specific SRS subframes that start a number of WTRU-specific SRS subframes after a triggering subframe. For multiple SRS transmissions from multiple antennas, cyclic shift multiplexing and different transmission combs may be used. The cyclic shift for an antenna may be determined from a cyclic shift reference value. The cyclic shift determined for each antenna providing a maximum distance between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe. SRS transmissions from multiple antennas in the WTRU-specific subframe may be done in parallel. Methods for handling collisions between SRS and physical channels are presented.

Claims

1. A method for performing uplink sounding reference signals (SRS) transmissions in a multiple antenna wireless transmit/receive unit (WTRU), comprising:

receiving a WTRU-specific configuration of WTRU-specific SRS subframes for performing SRS transmissions;

receiving a trigger from a base station to transmit SRS for a predetermined number of antennas; and

transmitting the SRS for the predetermined number of antennas in predetermined WTRU-specific subframes.

2. The method of claim 1, further comprising transmitting SRS in each of a predetermined duration of WTRU-specific SRS subframes starting a predetermined number of WTRU-specific SRS subframes after a triggering subframe.

3. The method of claim 2, wherein the predetermined number is 4.

4. The method of claim 1, wherein the trigger may be a multi-bit indicator that provides predetermined SRS transmission parameters to the WTRU.

5. The method of claim 1, further comprising:

receiving a cyclic shift reference value; and

determining a cyclic shift for an antenna based on at least the cyclic shift reference value.

6. The method of claim 5, wherein the cyclic shift determined for each antenna provides a maximum distance between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe.

7. The method of claim 5, wherein the cyclic shift determined for each antenna provides even distribution between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe.

8. The method of claim 1, wherein at least one of cyclic shift multiplexing or different transmission comb assignments is used for transmission from multiple antennas in the predetermined WTRU-specific subframe.

9. The method of claim 8, further comprising:

receiving a cyclic shift reference value; and

determining a cyclic shift for an antenna based on at least the cyclic shift reference value, wherein the cyclic shift determined for each antenna provides a maximum distance between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe.

10. The method of claim 1, wherein SRS transmissions from multiple antennas in the predetermined WTRU-specific subframe are done in parallel.

11. The method of claim 1, wherein the predetermined number of antennas is less than the number of antennas available on the WTRU.

12. The method of claim 1, wherein the WTRU-specific SRS subframes is different for periodic SRS transmission and aperiodic SRS transmission.

13. The method of claim 2, wherein the predetermined duration may be received in the WTRU-specific configuration.

14. The method of claim 1, further comprising:

determining resource allocation overlap between physical uplink shared channel (PUSCH) and the WTRU-specific configuration for SRS; and

foregoing PUSCH transmission in a last symbol of a subframe on a condition of a partial overlap.

15. A method of performing uplink sounding reference signals (SRS) transmissions in a multiple antenna wireless transmit/receive unit (WTRU), comprising:

receiving a cyclic shift reference value; and

determining a cyclic shift for an antenna based on at least the cyclic shift reference value.

16. The method of claim 15, wherein the cyclic shift determined for each antenna provides a maximum distance between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe.

17. The method of claim 15, wherein the cyclic shift determined for each antenna provides even distribution between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe.

18. A multiple antenna wireless transmit/receive unit (WTRU), comprising:

a receiver configured to receive a WTRU-specific configuration of WTRU-specific SRS subframes for performing SRS transmissions;

the receiver further configured to receive a trigger from a base station to transmit SRS for a predetermined number of antennas; and

a transmitter configured to transmit the SRS for the predetermined number of antennas in predetermined WTRU-specific subframes.

19. The WTRU of claim 18, wherein the transmitter is further configured to transmit SRS in each of a predetermined duration of WTRU-specific SRS subframes starting a predetermined number of WTRU-specific SRS subframes after a triggering subframe.

20. The WTRU of claim 19, further comprising:

the receiver being further configured to receive a cyclic shift reference value; and

a processor configured to determine a cyclic shift for an antenna based on at least the cyclic shift reference value,

wherein the cyclic shift determined for each antenna provides one of a maximum distance or even distribution between cyclic shifts for the antennas transmitting SRS in a same WTRU-specific subframe.