WiMAX enhanced sleep mode

• US 8,660,617 B1
• Filed: 12/19/2006
• Issued: 02/25/2014
• Est. Priority Date: 02/09/2006
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Banerjea, Raja, Ganton, Robert B., Donovan, Timothy J., Chowdhuri, Bhaskar
• Primary Examiner(s): WANG-HURST, KATHY W
• Application Number:
  US11/642,817
• Time in Patent Office: 2,625 Days
• Field of Search: 455/422.1, 455/572, 455/574, 4553431-3435, 370/208, 370/311
• US Class Current: 455/574
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0293 having a sub-controller with a low clock frequency switching on and off a main controller with a high clock frequency
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Power consumption is managed in a subscriber station of a communication system. The subscriber station is engaged in a sleep mode, including reducing a frequency of a system clock of the subscriber station. When the subscriber station receives, while in the sleep mode, a message having downlink transmission parameters while, the frequency of the system clock of the subscriber station is increased to process the message. After processing the message, the frequency of the system clock is reduced.

Claims

1. A method for managing power consumption in a subscriber station in a wireless communication system, the method comprising:

engaging the subscriber station in sleep mode; and

while the subscriber station is in the sleep mode,

receiving, at the subscriber station, a first portion of a frame, the first portion including (i) a downlink map (DLMAP) and (ii) at least one of (a) an uplink map (ULMAP) or (b) a downlink channel descriptor (DCD) message,

analyzing only the first portion to determine if there is a wake up indicator in the first portion at a location after (i) the DLMAP and (ii) at least one of (a) the ULMAP or (b) the DCD message, and

directing the subscriber station to exit the sleep mode if the wake up indicator is present in the first portion at the location after (i) the DLMAP and (ii) at least one of (a) the ULMAP or (b) the DCD message, or otherwise maintaining the subscriber station in the sleep mode.

2. The method of claim 1, wherein communication to and from the subscriber station is in accordance with IEEE Std. 802.16.

3. The method of claim 1, further comprising:

while the subscriber station is in the sleep mode,

receiving, at the subscriber station, one or more remaining portions of the frame, the one or more remaining portions including a plurality of control messages, and

storing the plurality of control messages in memory for later decoding; and

after the subscriber station exits the sleep mode, processing the plurality of control messages.

4. The method of claim 1, further comprising:

increasing a decoding clock rate and processing the present downlink map based on the increased decoding clock rate; and

decreasing the decoding clock rate after processing the received downlink map.

5. A method for managing power consumption in a subscriber station, the method comprising:

engaging the subscriber station in sleep mode, including reducing a frequency of a system clock in the subscriber station;

wirelessly receiving a message having downlink transmission parameters while the subscriber station is in the sleep mode;

in response to wirelessly receiving the message, increasing the frequency of the system clock to a frequency sufficient to process the message including gating a clock signal on to a portion of the subscriber station required to process the message during the time required to process the message; and

subsequent to processing the message, reducing the frequency of the system clock from the frequency sufficient to process the message.

6. The method of claim 5, wherein reducing the frequency of the system clock from the frequency sufficient to process the message comprises:

gating a clock signal off to the portion of the subscriber station required to process the message.

7. The method of claim 5, wherein increasing the frequency of the system clock to the frequency sufficient to process the message comprises:

increasing the frequency of a clock signal provided to a portion of the subscriber station required to process the message during the time required to process the message.

8. The method of claim 7, wherein reducing the frequency of the system clock from a frequency sufficient to process the message comprises:

decreasing the frequency of the clock signal provided to the portion of the subscriber station required to process the message.

22. The method of claim 5, wherein the message is a downlink map (DLMAP) message.

9. A method for managing power consumption in a subscriber station in a wireless communication system, the method comprising:

engaging the subscriber station in a sleep mode;

while the subscriber station is in the sleep mode, i) wirelessly receiving control messages that do not require immediate processing, and ii) storing the control messages without processing the control messages;

exiting the subscriber station from the sleep mode at a predetermined time to process a predetermined transmission wirelessly received, at the subscriber station, from a base station, the predetermined transmission including a downlink map;

after exiting the subscriber station from the sleep mode, processing the stored control messages before or after processing the predetermined transmission; and

re-engaging the subscriber station in the sleep mode after processing i) the predetermined transmission and ii) the stored control messages.

10. The method of claim 9, further comprising:

while processing the predetermined transmission, increasing a clock rate of a system clock in the subscriber station to permit decoding of the predetermined transmission during reception of the predetermined transmission.

11. An operating method for a subscriber station operable in a wireless communication system, the wireless communication system including a base station that communicates using multi-burst frames, the method comprising:

the subscriber station entering a low power sleep mode; and

while the subscriber station is in the low power sleep mode, detecting whether a mobile traffic indicator message is present in a wirelessly received first burst of the multi-burst frame by processing only a first portion of the multi-burst frame, wherein the mobile traffic indicator message follows a downlink map,

wherein if no mobile traffic indicator message is detected in the first burst of the multi-burst frame, the subscriber station maintaining the low power sleep mode, and

wherein if the mobile traffic indicator message is detected, decoding data packets transmitted by the base station for the subscriber station.

12. The method of claim 11, further comprising:

detecting at the subscriber station a downlink map transmitted by the base station;

increasing the frequency of a system clock to a processor in the subscriber station;

at the processor, processing the downlink map according to the increased system clock frequency;

after processing the downlink map, decreasing the frequency of the system clock to the processor in the subscriber station.

13. The method of claim 12, further comprising:

receiving control messages at the subscriber station while the subscriber station is in the low power sleep mode;

storing the received control messages without processing the received control messages;

after increasing frequency of the system clock, at the processor in the subscriber station, processing the received control messages before or after processing the downlink map.

14. A subscriber station operable in a wireless communication network including at least one base station, the subscriber station comprising:

a power control circuit operative to switch the subscriber station between a low power sleep mode and an active mode;

a receiver operative to demodulate radio signals transmitted as a multi-burst frame from the base station, the multi-burst frame including a downlink map; and

a processor coupled to the receiver and operative to decode the demodulated radio signals;

the processor operative to detect whether a mobile traffic indicator message is present in the multi-burst frame after the downlink map and in a first burst of the multi-burst frame by processing only a first portion of the multi-burst frame and, if the mobile traffic indicator message is detected, to direct the subscriber station to exit the low power sleep mode to decode data packets in the first burst before the power control circuit switches the subscriber station from the active mode to the low power sleep mode, wherein the power control circuit is operative to maintain the subscriber station in the low power sleep for the duration of the multi-burst frame mode if no mobile traffic indicator message in the first burst and after the downlink map is detected by the processor.

15. The subscriber station of claim 14, further comprising a clock control circuit operative to vary clock signals provided to the processor, the clock control circuit increasing the frequency of the clock signals provided to the processor in response to receipt of control information from the base station to permit faster decoding of the received control information, the clock control circuit decreasing the frequency of the clock signals provided to the processor upon completion of decoding of the received control information.

16. The subscriber station of claim 15, wherein the control information comprises the down link map.

17. The subscriber station of claim 14, further comprising a memory operative to store control messages demodulated by the receiver when the power control circuit maintains the subscriber station in the low power sleep mode, the processor being further operative to batch process the stored control messages when the power control circuit switches the subscriber station from the low power sleep mode to the active mode.

18. A base station operable to communicate with one or more subscriber stations in a wireless communication system, the base station comprising:

means for formatting a message to be communicated to a subscriber station, the message including a wake up indicator positioned in the message at a predetermined location at or near the beginning of a first burst in the message and following a downlink map in the message for wireless reception by the subscriber station so that the subscriber station can determine, while in a sleep mode, whether the wake up indicator is present in the message by processing only a first portion of the message; and

means for transmitting the message to the subscriber station.

19. A subscriber station operable in a wireless communication system, the subscriber station comprising:

means for demodulating radio signals wirelessly received from a remote base station, the radio signals including a frame having a plurality of bursts;

detecting means for detecting a mobile traffic indicator message positioned in the frame at a predetermined location at or near the beginning of a first burst of radio signals in the frame and following a downlink map in the frame by processing only a first portion of the frame and while the subscriber station is in sleep mode, the mobile traffic indicator message indicating that the first burst is intended for the subscriber station; and

decoding means responsive to the detecting means for decoding the demodulated radio signals.

20. The subscriber station of claim 19, further comprising:

power control means for placing the subscriber station in the sleep mode when no traffic is intended for the subscriber station and placing the subscriber station in an active mode when the mobile traffic indicator message indicates that the first burst is intended for the subscriber station.

21. The subscriber station of claim 19, further comprising:

clock control means for providing variable frequency clock signals to the decoding means, the clock control means varying the frequency of the clock signals based on content of the demodulated radio signals.