Reducing power consumption in a radio device by early receiver shut down

• US 7,509,150 B1
• Filed: 08/02/2005
• Issued: 03/24/2009
• Est. Priority Date: 08/02/2005
• Status: Active Grant

• Current Assignee: Harris Global Communications, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Simmons, Charles A.
• Primary Examiner(s): Nguyen, Tu X
• Application Number:
  US11/194,464
• Time in Patent Office: 1,330 Days
• Field of Search: 455/502, 455/67.15, 455/436, 455/574, 455/127.5, 370/321, 370/337, 370/347
• US Class Current: 455/574
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A power savings technique is provided for a radio communication device. The technique involves reducing the amount of time that a receiver is powered-up during a time interval that the radio communication device may receive a transmission from another radio communication device. This time interval is referred to as a reception time interval, though it may also correspond to a time interval that the device may transmit to another device if the device is in a transmit mode. This method involves delaying enablement of the receiver for a relatively short first time interval that begins at the start of the reception time interval. When the first time interval expires, the receiver is enabled for at least a second time interval so that the device can detect whether a synchronization pattern is occurring, indicative of a radio transmission being sent for the device. The duration of the second time interval is such that it expires well before the end of the reception time interval. If the device does not detect the synchronization pattern during the second time interval, the receiver is powered-down or disabled. The durations of the first and second time intervals may be set by first and second timers, respectively. Consequently, the receiver is disabled before the end of the reception interval when there is no transmission to the device that is to be received.

Claims

1. A method for reducing power consumption of a radio communication device, comprising:

a. determining a start of a reception time interval comprising an assigned time slot during which the radio communication device may receive a transmission from another radio communication device, and wherein determining comprises monitoring a status of a time slot timer to determine the start of said assigned time slot when said time slot timer times out;

b. after expiration of a first time interval that begins at the start of the reception time interval, enabling the receiver for at least a second time interval that expires prior to expiration of the reception time interval;

c. during said second time interval, detecting whether a synchronization pattern is being transmitted to the radio communication device, which synchronization pattern is indicative of a transmission that follows the synchronization pattern during the reception time interval to the radio communication device from another radio communication device; and

d. maintaining the receiver enabled beyond the second time interval during said reception time interval if the synchronization pattern is detected during said second time interval, otherwise placing the receiver in a low power consumption mode at expiration of the second time interval.

2. The method of claim 1, and further comprising activating a first timer in response to determining that the time slot timer has timed out, wherein the first timer has a duration equal to the first time interval.

3. The method of claim 2, and further comprising activating a second timer having a duration equal to the second time interval.

4. The method of claim 3, wherein placing the receiver in the low power mode comprises placing the receiver in the low power mode when the second timer times out without detection of the synchronization pattern.

5. The method of claim 1, wherein enabling comprises enabling the receiver for the second time interval that at least partially overlaps with the occurrence of the transmission to the radio communication device from another radio communication device that is responsive to a transmission from said radio communication device.

6. The method of claim 1, wherein enabling comprises one or both of:

connecting power to the receiver, and activating generation of a clock signal for the receiver operations.

7. The method of claim 1, wherein placing the receiver in the low power mode comprises one or both of:

disconnecting power to the receiver, and terminating generation of a clock signal for the receiver operations.

8. A method for reducing power consumption of a radio communication device, comprising:

a. enabling a receiver in the radio communication device for a time interval that at least partially overlaps with an assigned time slot of the radio communication device during which a message may be transmitted to the radio communication device from another radio communication device, but which time interval is shorter in duration than the assigned time slot;

b. during said time interval, detecting whether a synchronization pattern is being transmitted to the radio communication device, which synchronization pattern is indicative of a message transmission to the radio communication device; and

c. maintaining the receiver enabled beyond the time interval if the synchronization pattern is detected during said time interval, otherwise disabling the receiver at expiration of the time interval.

9. The method of claim 8, wherein enabling comprises enabling the receiver in the radio communication device after expiration of a time interval that starts at the beginning of the assigned time slot.

10. The method of claim 8, wherein enabling comprises one or both of:

connecting power to the receiver, and activating generation of a clock signal for the receiver operations.

11. The method of claim 8, wherein disabling comprises one or both of:

disconnecting power to the receiver, and terminating generation of a clock signal for the receiver operations.

12. A radio communication device comprising:

a radio receiver that is configured to receive wireless radio frequency energy including signals from other radio communication devices;

a first timer that times out after a first time interval;

a time slot timer that times out at the start of an assigned time slot;

a second timer that times out after a second time interval; and

a processor coupled to the radio receiver, the first timer and the second timer, wherein the processor is configured to;

monitor the time slot timer to determine the start of the assigned time slot;

activate the first timer at the start of a reception time interval corresponding to the assigned time slot during which the radio communication device may receive a transmission from another radio communication device;

activate the second timer after expiration of the first timer and enable the radio receiver in order to detect whether a synchronization pattern is being transmitted to the radio communication device during the second time interval, which synchronization pattern is indicative of a transmission that follows the synchronization pattern to the radio communication device during said reception time interval; and

maintain the receiver enabled beyond the second time interval during said reception time interval if the synchronization pattern is detected during the second time interval, otherwise disable the receiver at expiration of the second time interval which second time interval expires prior to expiration of the reception time interval.

13. The radio communication device of claim 12, wherein the processor enables the receiver for the second time interval that at least partially overlaps with the occurrence of the transmission to the radio communication device from another radio communication that is responsive to a transmission from said radio communication device.

14. The radio communication device of claim 12, wherein the processor enables the receiver by one or both of:

causing connection of power to the receiver, and activating generation of a clock signal for the receiver operations.

15. The radio communication device of claim 12, wherein the processor disables the receiver by one or both of:

causing disconnection of power to the receiver, and terminating generation of a clock signal for the receiver operations.