Preamble based uplink power control for LTE

• US 7,986,959 B2
• Filed: 02/13/2008
• Issued: 07/26/2011
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Malladi, Durga Prasad, Montojo, Juan
• Primary Examiner(s): Nguyen; Tu X
• Application Number:
  US12/030,333
• Publication Number:
  US 20080207150A1
• Time in Patent Office: 1,259 Days
• Field of Search: 455/69, 455/522, 455/13.4, 370/335
• US Class Current: 455/522
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Systems and methodologies are described that facilitate utilizing power control preambles with closed loop power control techniques in a wireless communication environment. An uplink grant can be transferred over a downlink (e.g., a first uplink grant after uplink inactivity), and a power control preamble can be sent over an uplink in response to the uplink grant. According to an example, transmission of the power control preamble can be explicitly scheduled and/or implicitly scheduled. The power control preamble can be transmitted at a power level determined by an access terminal utilizing an open loop power control mechanism. A base station can analyze the power control preamble and generate a power control command based thereupon to correct the power level employed by the access terminal. The access terminal can thereafter utilize the power control command to adjust the power level for uplink data transmission.

Claims

1. A method that facilitates generating a power control preamble for utilization in a wireless communication environment, comprising:

receiving an uplink grant from a base station, the uplink grant being a first uplink grant after uplink inactivity;

transmitting a power control preamble to the base station with a power setting based on open loop power control;

receiving a power control command from the base station, the power control command adjusts the power setting; and

transmitting data to the base station with the adjusted power setting.

2. The method of claim 1, wherein the power control preamble is an uplink transmission that sounds a channel over part or an entire system bandwidth by employing hops in a given transmission time interval (TTI).

3. The method of claim 1, wherein the power control preamble is a single-time Sounding Reference Signal (SRS) transmission.

4. The method of claim 1, wherein the power control preamble is an aperiodic Channel Quality Indicator (CQI) report on an uplink data channel.

5. The method of claim 1, wherein transmission characteristics of the power control preamble are explicitly indicated.

6. The method of claim 5, further comprising:

transmitting the power control preamble in response to the uplink grant utilizing at least one of a resource, a modulation, or a coding explicitly specified in the uplink grant;

receiving a second uplink grant from the base station along with the power control command; and

transmitting the data to the base station by utilizing the second uplink grant received with the power control command.

7. The method of claim 1, wherein transmission characteristics of the power control preamble are implicitly indicated.

8. The method of claim 7, further comprising:

transmitting the power control preamble in response to the uplink grant utilizing at least one of a predetermined resource, a predetermined modulation, or a predetermined coding, the at least one of the predetermined source, the predetermined modulation or the predetermined coding being set forth to an access terminal and the base station prior to reception of the uplink grant;

transmitting the data to the base station by utilizing the uplink grant received prior to reception of the power control command.

9. The method of claim 1, further comprising receiving a power control command in response to the data transmission.

10. A wireless communications apparatus, comprising:

a memory that retains instructions related to obtaining an uplink grant from a base station, the uplink grant being a first uplink grant after uplink inactivity, determining a power level for power control preamble transmission based upon an open loop evaluation, sending a power control preamble to the base station at the power level, receiving a power control command from the base station, altering the power level based upon the power control command, and sending an uplink data transmission to the base station at a power level that has been altered in accordance to the power control command; and

a processor, coupled to the memory, configured to execute the instructions retained in the memory.

11. The wireless communications apparatus of claim 10, wherein the power control preamble is an uplink transmission that sounds a channel over part or an entire system bandwidth by employing hops in a given transmission time interval (TTI).

12. The wireless communications apparatus of claim 10, wherein the power control preamble is a single-time Sounding Reference Signal (SRS) transmission.

13. The wireless communications apparatus of claim 10, wherein the power control preamble is an aperiodic Channel Quality Indicator (CQI) report on an uplink data channel.

14. The wireless communications apparatus of claim 10, wherein transmission characteristics of the power control preamble are explicitly indicated.

15. The wireless communications apparatus of claim 14, wherein the memory further retains instruction related to sending the power control preamble in response to the uplink grant utilizing information explicitly specified in the uplink grant, obtaining a second uplink grant from the base station along with the power control command, and sending the uplink data transmission by utilizing the second uplink grant obtained concurrently with the power control command.

16. The wireless communications apparatus of claim 10, wherein transmission characteristics of the power control preamble are implicitly indicated.

17. The wireless communications apparatus of claim 16, wherein the memory further retains instruction related to sending the power control preamble in response to the uplink grant utilizing predetermined information preset for an access terminal and the base station before obtaining the uplink grant, and sending the uplink data transmission by utilizing the uplink grant received prior to obtaining the power control command.

18. The wireless communications apparatus of claim 10, wherein the memory further retains instruction related to obtaining a power control command in response to the uplink data transmission.

19. A wireless communications apparatus that enables utilizing power control preambles in a wireless communication environment, comprising:

means for obtaining an uplink grant, the uplink grant being a first uplink subsequent to uplink inactivity;

means for transferring an uplink power control preamble at a power level selected as a function of an open loop power control estimate;

means for obtaining a power control command that alters the power level; and

means for transmitting uplink data at the altered power level.

20. The wireless communications apparatus of claim 19, wherein the uplink power control preamble is an uplink transmission that sounds a channel and spans part or an entire system bandwidth by employing hops in a given transmission time interval (TTI).

21. The wireless communications apparatus of claim 19, wherein the uplink power control preamble is a single-time Sounding Reference Signal (SRS) transmission.

22. The wireless communications apparatus of claim 19, wherein the uplink power control preamble is an aperiodic Channel Quality Indicator (CQI) report on an uplink data channel.

23. The wireless communications apparatus of claim 19, further comprising:

means for transferring the uplink power control preamble in response to the uplink grant by employing information explicitly included with the uplink grant when transfer of the uplink power control preamble is explicitly scheduled;

means for obtaining a second uplink grant contemporaneously with the power control command; and

means for transmitting the uplink data in response to the second uplink grant obtained contemporaneously with the power control command.

24. The wireless communications apparatus of claim 19, further comprising:

means for transferring the uplink power control preamble in response to the uplink grant utilizing predetermined information known a priori by an access terminal and the base station before obtaining the uplink grant when transfer of the uplink power control preamble is implicitly scheduled; and

means for transmitting the uplink data by utilizing the uplink grant received prior to obtaining the power control command.

25. The wireless communications apparatus of claim 19, further comprising means for obtaining a power control command in response to the uplink data transmission.

26. A machine-readable medium having stored thereon machine-executable instructions for:

obtaining an uplink grant, the uplink grant being a first uplink grant after uplink inactivity;

transferring an uplink power control preamble at a power level selected as a function of an open loop power control estimate;

obtaining a power control command that alters the power level; and

transmitting uplink data at the altered power level.

27. The machine-readable medium of claim 26, wherein the uplink power control preamble is an uplink transmission that sounds a channel and spans part or an entire system bandwidth by employing hops in a given transmission time interval (TTI).

28. The machine-readable medium of claim 26, wherein the uplink power control preamble is a single-time Sounding Reference Signal (SRS) transmission.

29. The machine-readable medium of claim 26, wherein the uplink power control preamble is an aperiodic Channel Quality Indicator (CQI) report on an uplink data channel.

30. The machine-readable medium of claim 26, the machine-executable instructions further comprise transferring the uplink power control preamble in response to the uplink grant by employing information explicitly included with the uplink grant when transfer of the uplink power control preamble is explicitly scheduled, obtaining a second uplink grant contemporaneously with the power control command, and transmitting the uplink data in response to the second uplink grant obtained contemporaneously with the power control command.

31. The machine-readable medium of claim 26, the machine-executable instructions further comprise transferring the uplink power control preamble in response to the uplink grant utilizing predetermined information known a priori by an access terminal and the base station before obtaining the uplink grant when transfer of the uplink power control preamble is implicitly scheduled, and transmitting the uplink data by utilizing the uplink grant received prior to obtaining the power control command.

32. The machine-readable medium of claim 26, the machine-executable instructions further comprise obtaining a power control command in response to the uplink data transmission.

33. In a wireless communications system, an apparatus comprising:

a processor configured to;

obtain an uplink grant from a base station, the uplink grant being a first uplink grant subsequent to uplink inactivity;

determine a power level for power control preamble transmission based upon an open loop evaluation;

send a power control preamble to the base station at the power level;

receive a power control command from the base station;

alter the power level based upon the power control command; and

send an uplink data transmission to the base station at the altered power level.