Methods and apparatus for use in a wireless communications system that uses a multi-mode base station

• US 8,340,703 B2
• Filed: 07/09/2010
• Issued: 12/25/2012
• Est. Priority Date: 09/19/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Anigstein, Pablo, Das, Arnab, Rangan, Sundeep
• Primary Examiner(s): Alam, Fayyaz
• Application Number:
  US12/833,318
• Publication Number:
  US 20110085611A1
• Time in Patent Office: 900 Days
• Field of Search: 455/561, 455/562.1, 455/522, 455 69- 70, 455/502
• US Class Current: 455/502
• CPC Class Codes: H04B 7/2678 Time synchronisation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A multi-mode base station includes a transmit standby mode and an active mode. Transmit standby mode of base station operation is a low power/low interference level of operation as compared to active mode. In transmit standby mode at least some of the synchronization signaling such as pilot tone signaling is reduced in power level and/or rate with respect to the active mode. In transmit standby mode, the base station has no active state registered wireless terminals being serviced but may have some sleep state registered wireless terminals being serviced. Mode transitions from active to transmit standby may be in response to: a detected period of inactivity, scheduling information, base station mode change signals, and/or detected wireless terminal state transition. Mode transitions from transmit standby to active may be in response to: scheduling information, access signals, wake-up signals, hand-off signals, wireless terminal state change signals, and/or base station mode change signals.

Claims

1. A method operating a base station, comprising:

transmitting pilot signals at a first rate during a first time period, the first time period corresponding to a standby mode of the base station;

transmitting pilot signals at a second rate higher than the first rate during a second time period, the second time period corresponding to a transmit mode of the base station.

2. The method of claim 1 further comprising transitioning from the standby mode to the active mode in response to at least one of a detected period of inactivity, scheduling information, a mode change signal and a wireless terminal state transition.

3. The method of claim 2 wherein the scheduling information is one of a train schedule and a commuter schedule.

4. The method of claim 1 wherein

the first rate and second rate correspond to a first and a second OFDM time frequency grid, and

pilot signals of the second OFDM time frequency grid are positioned to be transmitted at the same time as pilot signals on the first OFDM time frequency grid.

5. A method operating a base station, comprising:

transmitting pilot signals at a first power level during a first time period, the first time period corresponding to a standby mode of the base station;

transmitting pilot signals at a second power less than the first power level during a second time period, the second time period corresponding to a transmit mode of the base station.

6. The method of claim 5 further comprising transitioning from the standby mode to the active mode in response to at least one of a detected period of inactivity, scheduling information, a mode change signal and a wireless terminal state transition.

7. The method of claim 6 wherein the scheduling information is one of a train schedule and a commuter schedule.

8. An apparatus for controlling operation of a base station, the apparatus comprising:

means for transmitting pilot signals at a first rate during a first time period, the first time period corresponding to a standby mode of the base station;

means for transmitting pilot signals at a second rate higher than the first rate during a second time period, the second time period corresponding to a transmit mode of the base station.

9. The apparatus of claim 8 further comprising means for transitioning from the standby mode to the active mode in response to at least one of a detected period of inactivity, scheduling information, a mode change signal and a wireless terminal state transition.

10. The apparatus of claim 9 wherein the scheduling information is one of a train schedule and a commuter schedule.

11. The apparatus of claim 8 wherein

the first rate and second rate correspond to a first and a second OFDM time frequency grid, and

pilot signals of the second OFDM time frequency grid are positioned to be transmitted at the same time as pilot signals on the first OFDM time frequency grid.

12. The apparatus of claim 11 wherein

the first rate and second rate correspond to a first and a second OFDM time frequency grid, and

pilot signals of the second OFDM time frequency grid are positioned to be transmitted at the same frequency as pilot signals on the first OFDM time frequency grid.

13. An apparatus for operating a base station, comprising:

means for transmitting pilot signals at a first power level during a first time period, the first time period corresponding to a standby mode of the base station;

means for transmitting pilot signals at a second power less than the first power level during a second time period, the second time period corresponding to a transmit mode of the base station.

14. The apparatus of claim 13 farther comprising means for transitioning from the standby mode to the active mode in response to at least one of a detected period of inactivity, scheduling information, a mode change signal and a wireless terminal state transition.

15. The apparatus of claim 14 wherein the scheduling information is one of a train schedule and a commuter schedule.

16. An apparatus for controlling operation of a base station, the apparatus comprising:

a transmitter adapted to transmit pilot signals at a first rate during a first time period, the first time period corresponding to a standby mode of the base station, and

adapted to transmit pilot signals at a second rate higher than the first rate during a second time period, the second time period corresponding to a transmit mode of the base station;

and a controller coupled to the transmitter for setting the mode of the base station.

17. The apparatus of claim 16 further wherein the controller transitions the base station from the standby mode to the active mode in response to at least one of a detected period of inactivity, scheduling information, a mode change signal and a wireless terminal state transition.

18. The apparatus of claim 17 wherein the scheduling information is one of a train schedule and a commuter schedule.

19. The apparatus of claim 16 wherein

the first rate and second rate correspond to a first and a second OFDM time frequency grid, and

pilot signals of the second OFDM time frequency grid are positioned to be transmitted at the same time as pilot signals on the first OFDM time frequency grid.

20. The apparatus of claim 19 wherein

the first rate and second rate correspond to a first and a second OFDM time frequency grid, and

pilot signals of the second OFDM time frequency grid are positioned to be transmitted at the same frequency as pilot signals on the first OFDM time frequency grid.

21. An apparatus for operating abase station, comprising:

a transmitter adapted to transmit pilot signals at a first power level during a first time period, the first time period corresponding to a standby mode of the base station, and

adapted to transmit pilot signals at a second power less than the first power level during a second time period, the second time period corresponding to a transmit mode of the base station; and

and a controller coupled to the transmitter for setting the mode of the base station.

22. The apparatus of claim 21 further wherein the controller is adapted to transition the base station from the standby mode to the active mode in response to at least one of a detected period of inactivity, scheduling information, a mode change signal and a wireless terminal state transition.

23. The apparatus of claim 22 wherein the scheduling information is one of a train schedule and a commuter schedule.

24. A computer program product embodied on a tangible medium, the computer program product comprising:

instructions for transmitting pilot signals at a first rate during a first time period, the first time period corresponding to a standby mode of a base station, and

instructions for transmitting pilot signals at a second rate higher than the first rate during a second time period, the second time period corresponding to a transmit mode of the base station.

25. A computer program product embodied on a tangible medium, the computer program product comprising:

instructions for transmitting pilot signals at a first power during a first time period, the first time period corresponding to a standby mode of a base station, and

instructions for transmitting pilot signals at a second power higher than the first power during a second time period, the second time period corresponding to a transmit mode of the base station.