Passive listening in wireless communication

• US 8,243,638 B2
• Filed: 01/08/2007
• Issued: 08/14/2012
• Est. Priority Date: 01/08/2007
• Status: Active Grant

• Current Assignee: Nordic Semiconductor ASA
• Original Assignee: Hellosoft Incorporated (Imagination Technologies Group Ltd.)
• Inventors: Aldaz, legal representative, Luis Sr., Barman, Kaushik, Johnson, Allan A., Malladi, Raghavendra, Dighe, Parag Ashok, Aldaz, Luis, Kankipati, Sriram
• Primary Examiner(s): Phunkulh, Bob
• Assistant Examiner(s): Van, Jenkey
• Application Number:
  US11/651,287
• Publication Number:
  US 20080165780A1
• Time in Patent Office: 2,045 Days
• Field of Search: None
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Passive listening in wireless communication. An activity sensor device senses a packet. A medium access control (MAC) address parser receives the packet, processes a header of the packet, and activates a MAC device in response to recognizing a MAC address within the header, such that the MAC device is not activated if the MAC address parser does not recognize the MAC address.

Claims

1. An apparatus comprising:

a network physical layer device;

an activity sensor device for sensing a packet, sensing a silence-to-energy event at a beginning of said packet, and activating the network physical layer device from a shutdown state in response to sensing said packet and said silence-to-energy event, and wherein said activity sensor device is configured for being deactivated subsequent sensing said packet such that said activity sensor device is deactivated at least for a length of said packet;

said network physical layer device for decoding a physical (PHY) header portion and a Media Access Control header portion of a header of said packet following activation from said shutdown state;

a media access controller comprising a fixed hardware media access plane implementing IEEE 802.11 series media access control functionality and comprising a receive packet process unit coupled to a programmable microprocessor through a bus interface; and

a media access control address parser for receiving the Media Access Control header portion of said packet, for processing the Media Access Control header portion of said packet, for activating the media access controller from a shutdown state in response to recognizing a Media Access Control address within said Media Access Control header portion, and for deactivating the network physical layer device responsive to the media access control address parser not recognizing the Media Access Control address and such that the media access controller is not activated if the media access control address parser does not recognize the Media Access Control address, wherein

the media access controller is operable, after activation, to perform the media access control functionality without using the programmable microprocessor and to provide data from the packet to the programmable microprocessor through the bus interface.

2. The apparatus as recited in claim 1, wherein said physical layer device is deactivated subsequent decoding said header of said packet.

3. The apparatus as recited in claim 1 wherein said activity sensor comprises:

a radio frequency (RF) and mixed signal model for receiving a signal comprising said packet.

4. A method comprising:

sensing a packet and a silence-to-energy event at an activity sensor device;

responsive to said sensing, activating a network physical layer device from a shutdown state, said activity sensor device performing said activating;

decoding at least a physical layer portion and a media access control layer portion of a header of said packet at said network physical layer device, said media access control layer portion of the header including a destination media access control address;

deactivating said activity sensor device for at least a length of said packet;

determining whether said destination media access control address from the media access control layer portion of the header of said packet is recognized, the determining performed by a media access control address parser for receiving the media access control header portion of said packet, for processing the media access control header portion of said packet;

responsive to recognizing said destination media access control address, activating a fixed function hardware media access controller comprising a fixed hardware media access plane implementing IEEE 802.11 series media access control functionality and comprising a receive packet process unit coupled to a programmable microprocessor through a bus interface, from a shutdown state for performing data processing functions such that said fixed function hardware media access controller is not activated if said destination media access control address is not recognized;

deactivating the network physical layer device responsive to the media access control address parser not recognizing the destination media access control address;

reactivating said activity sensor device upon a passing of said length of said packet; and

performing, at the fixed function hardware media access controller, after activation, media access control functionality without using the programmable microprocessor and to provide data form the packet to the programmable microprocessor.

5. The method as recited in claim 4 further comprising:

deactivating said physical layer device subsequent said decoding at least said header of said packet at said physical layer device; and

reactivating said physical layer device upon receiving a header from a subsequent packet from said activity sensor sensing said subsequent packet.

6. The method as recited in claim 4 further comprising:

deactivating said media access control address parser subsequent said determining whether said media access control address of said packet is recognized; and

reactivating said media access control address parser for receiving said header portion from said network physical layer device.