METHOD AND APPARATUS FOR CONFIGURING VARIABLE CQI REPORTING PERIOD IN A WIRELESS COMMUNICATION SYSTEM

• US 20120314588A1
• Filed: 06/09/2011
• Published: 12/13/2012
• Est. Priority Date: 06/09/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nammi, Sairamesh
• Granted Patent: US 8,670,343 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0027 Scheduling of signalling, e.g. occurrence thereof
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports

Abstract

A system and method for configuring a variable Channel Quality Information (CQI) reporting period based on a User Equipment'"'"'s (UE) Doppler frequency or speed. Mobile users are divided into three Doppler frequency regions based on their speed—for example, low, medium, and high Doppler users—and are assigned the CQI, reporting periods accordingly by the base station. The users in the low and high Doppler regions (i.e., UEs with low and high speeds) receive a high value for the CQI reporting period, whereas—the users in the medium Doppler region (i.e., UEs with medium speeds) receive a low value for the CQI reporting period. The UE speed-specific CQI reporting period improves the uplink capacity by adaptively controlling a UE'"'"'s CQI-related uplink transmissions, without compromising on the downlink capacity/throughput.

Claims

1. A method of determining a Channel Quality Information (CQI) reporting period of a User Equipment (UE) that is in wireless communication with a processor via a wireless network associated therewith, the method comprising the steps of:

using the processor, determining a Doppler frequency region of the UE, wherein the Doppler frequency region of the UE includes one of the following;

a low Doppler frequency region when the speed of the UE is below a first predetermined threshold,

a high Doppler frequency region when the speed of the UE is at or above a second predetermined threshold, and

a medium Doppler frequency region when the speed of the UE is at or above the first predetermined threshold, but below the second predetermined threshold; and

using the processor, configuring the CQI reporting period of the UE based on the determination of the Doppler frequency region of the UE, wherein the CQI reporting period is configured to one of the following values;

a first predetermined value when the Doppler frequency region of the UE is either the low Doppler frequency region or the high Doppler frequency region, and

a second predetermined value when the Doppler frequency region of the UE is the medium Doppler frequency region, wherein the second predetermined value is lower than the first predetermined value.

3. The method of claim 1, wherein determining the Doppler frequency region of the UE includes at least one of the following:

determining the Doppler frequency region of the UE based on a rate of change of the UE'"'"'s uplink transmission frequency location over two successive Transmit Time Intervals (TTIs);

determining the Doppler frequency region of the UE based on a rate of change of the CQI reported to the processor by the UE over two successive TTIs; and

determining the Doppler frequency region of the UE based on a range of change of a Precoding Matrix Information (PMI) reported to the processor by the UE over two successive TTIs.

4. The method of claim 3, wherein the Doppler frequency region determined based on the rate of change of the UE'"'"'s uplink transmission frequency location includes one of the following:

the low Doppler frequency region when the rate of change of the UE'"'"'s uplink transmission frequency location is below a third predetermined threshold, wherein the third predetermined threshold is representative of the first predetermined threshold;

the high Doppler frequency region when the rate of change of the UE'"'"'s uplink transmission frequency location is above a fourth predetermined threshold, wherein the fourth predetermined threshold is representative of the second predetermined threshold; and

the medium Doppler frequency region when the rate of change of the UE'"'"'s uplink transmission frequency location is between the third and the fourth predetermined thresholds.

5. The method of claim 3, wherein the Doppler frequency region determined based on the rate of change of the reported CQI includes one of the following:

the low Doppler frequency region when the rate of change of the reported CQI is below a third predetermined threshold, wherein the third predetermined threshold is representative of the first predetermined threshold;

the high Doppler frequency region when the rate of change of the reported CQI is above a fourth predetermined threshold, wherein the fourth predetermined threshold is representative of the second predetermined threshold; and

the medium Doppler frequency region when the rate of change of the reported CQI is between the third and the fourth predetermined thresholds.

6. The method of claim 3, wherein the Doppler frequency region determined based on the rate of change of the reported PMI includes one of the following:

the low Doppler frequency region when the rate of change of the reported PMI is below a third predetermined threshold, wherein the third predetermined threshold is representative of the first predetermined threshold;

the high Doppler frequency region when the rate of change of the reported PMI is above a fourth predetermined threshold, wherein the fourth predetermined threshold is representative of the second predetermined threshold; and

the medium Doppler frequency region when the rate of change of the reported PMI is between the third and the fourth predetermined thresholds.

7. The method of claim 3, wherein the two successive TT'"'"'s belong to a single uplink radio frame.

8. The method of claim 1, further comprising:

using the processor, instructing the UE to use the CQI reporting period configured by the processor.

9. The method of claim 1, further comprising:

using the processor, evoking a separate physical uplink channel prior to determining the Doppler frequency region of the UE; and

using the processor, receiving uplink communication from the UE over the separate physical uplink channel so as to determine the Doppler frequency region of the UE.

10. The method of claim 9, wherein the separate physical uplink channel is evoked when

11. The method of claim 1, further comprising:

using the processor, repeating the determining and the configuring steps after a predetermined time interval.

2. The method of claim 2, wherein the first predetermined value is in the range of 50 ms to 100 ms, and wherein the second predetermined value is in the range of 5 ms to 10 ms.

12. A method of setting a Channel Quality Information (CQI) reporting period of a User Equipment (UE) that is in wireless communication with a processor via a wireless network associated therewith, the method comprising the steps of:

using the processor, assigning a Doppler frequency region to the UE based on the speed of the UE estimated by the processor, wherein the Doppler frequency region of the UE includes one of the following;

a low Doppler frequency region when the estimated speed of the UE is below a first predetermined threshold,

a high Doppler frequency region when the estimated speed of the UE is at or above a second predetermined threshold, and

a medium Doppler frequency region when the estimated speed of the UE is at the first predetermined threshold or between the first and the second predetermined thresholds; and

using the processor, setting the CQI reporting period of the UE based on the assigned Doppler frequency region to the UE, wherein the CQI reporting period is set to one of the following values;

a first predetermined value when the Doppler frequency region of the UE is either the low Doppler frequency region or the high Doppler frequency region, and

a second predetermined value when the Doppler frequency region of the UE is the medium Doppler frequency region, wherein the second predetermined value is lower than the first predetermined value.

13. A mobile communication node that is in wireless communication with a User Equipment (UE) via a wireless network associated with the UE, wherein the mobile communication node is configured to perform the following:

determine a Doppler frequency region of the UE, wherein the Doppler frequency region of the UE includes one of the following;

a low Doppler frequency region when the estimated Doppler frequency of the UE is below a first predetermined threshold,

a high Doppler frequency region when the estimated Doppler frequency of the UE is at or above a second predetermined threshold, and

a medium Doppler frequency region when the estimated Doppler frequency of the UE is at or above the first predetermined threshold, but below the second predetermined threshold; and

set a Channel Quality Information (CQI) reporting period of the UE to one of the following values;

a first predetermined value when the Doppler frequency region of the UE is either the low Doppler frequency region or the high Doppler frequency region, and

a second predetermined value when the Doppler frequency region of the UE is the medium Doppler frequency region, wherein the second predetermined value is lower than the first predetermined value.

14. The mobile communication node of claim 13, further configured to perform one of the following as part of determining the Doppler frequency region of the UE:

determine the Doppler frequency region of the UE based on a rate of change of the UE'"'"'s uplink transmission frequency location over two successive Transmit Time Intervals (TTIs);

determine the Doppler frequency region of the UE based on a rate of change of the CQI reports received from the UE over two successive TTIs; and

determine the Doppler frequency region of the UE based on a range of change of Precoding Matrix Information (PMI) reports received from the UE over two successive TTIs.

15. The mobile communication node of claim 13, further configured to transmit to the UE the value of the CQI reporting period set thereby.

16. The mobile communication node of claim 13, further configured to perform the following:

evoke a separate physical uplink channel prior to determining the Doppler frequency region of the UE; and

receive uplink communication from the UE over the separate physical uplink channel so as to determine the Doppler frequency region of the UE.

17. A system comprising:

a mobile communication node that is in wireless communication with a mobile handset via a wireless network associated with the mobile handset, wherein the mobile communication node is configured to perform the following;

determine a Doppler frequency region of the mobile handset, wherein the Doppler frequency region of the mobile handset includes one of the following;

a low Doppler frequency region when the speed of the mobile handset is below a first predetermined threshold,

a high Doppler frequency region when the speed of the mobile handset is at or above a second predetermined threshold, and

a medium Doppler frequency region when the speed of the mobile handset is at or above the first predetermined threshold, but below the second predetermined threshold,

set a Channel Quality Information (CQI) reporting period of the mobile handset to one of the following values;

a first predetermined value when the Doppler frequency region of the mobile handset is either the low Doppler frequency region or the high Doppler frequency region, and

a second predetermined value when the Doppler frequency region of the mobile handset is the medium Doppler frequency region, wherein the second predetermined value is lower than the first predetermined value, and

send the value of the CQI reporting period to the mobile handset; and

the mobile handset that is configured to use the value of the CQI reporting period received from the mobile communication node when sending a CQI report to the mobile communication node.

18. The system of claim 17, wherein the first predetermined value is in the range of 50 ms to 100 ms, and wherein the second predetermined value is in the range of 5 ms to 10 ms.

19. The system of claim 17, wherein the mobile communication node is further configured to perform the following:

evoke a separate physical uplink channel prior to determining the Doppler frequency region of the mobile handset; and

receive uplink communication from the mobile handset over the separate physical uplink channel so as to determine the Doppler frequency region of the mobile handset.

20. The system of claim 17, wherein the mobile communication node is further configured to repeat determination of the Doppler frequency region, setting of the CQI reporting period, and sending of the value of the CQI reporting period after a predetermined time interval.