Self-configuring physical carrier sensing threshold adaptation

• US 7,463,644 B2
• Filed: 03/31/2004
• Issued: 12/09/2008
• Est. Priority Date: 12/11/2003
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Hazra, Mousumi M., Guo, Xingang, Conner, W. Steven, Zhu, Jing, Yang, Liuyang Lily
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Hailu; Kibrom T
• Application Number:
  US10/816,434
• Publication Number:
  US 20050129051A1
• Time in Patent Office: 1,714 Days
• Field of Search: 370/445, 370/463, 370/437, 370/455, 370/343, 370/349, 370/333, 455/134, 455/135
• US Class Current: 370/445
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Apparatuses and methods for dynamically adjusting carrier sensing threshold levels in a wireless, such as CSMA, system. A station may use the carrier sensing measurement made in normal CSMA operation to determine a threshold level for the local station, and transmit the determined level to other stations in the system. The station also receives similar information from other stations in the system and determines, based at least in part on the information received and the local determined threshold level, an optimal carrier sensing threshold level.

Claims

1. A method comprising:

measuring a communication channel characteristic of a wireless communication channel for a local wireless network node of a network of nodes;

determining a local transmission threshold for the local wireless network node based on the measured communication channel characteristic, wherein the local transmission threshold includes a physical carrier sense threshold indicating a threshold level of interference that is tolerable for a physical layer of the local wireless network node, where interference sensed in the network by the local wireless network node exceeding the local transmission threshold causes the local wireless network node to back off from transmission;

receiving a transmission threshold from a remote network node, the received transmission threshold indicating a threshold level of interference that is tolerable for a physical layer of the remote network node, where interference sensed in the network by the remote network node exceeding the received transmission threshold causes the remote network node to back off from transmission; and

adjusting automatically the hardware settings of the physical layer of the local wireless network node based on the local transmission threshold and the received transmission threshold, including selecting the lower transmission threshold of the local transmission threshold and the received transmission threshold, and adjusting the hardware settings to make the wireless network node responsive to the selected transmission threshold, where interference exceeding the selected transmission threshold causes the local wireless network node to back off from transmission on the wireless communication channel.

2. A method according to claim 1, wherein measuring the communication channel characteristic comprises determining a signal to noise-plus-interference ratio (SNIR) for the communication channel for the local wireless network node.

3. A method according to claim 1, further comprising transmitting the determined local transmission threshold to another node in the wireless network.

4. A method according to claim 1, wherein adjusting the hardware settings of the local wireless network node is performed at periodic intervals, and the hardware settings remain constant throughout the interval.

5. A method according to claim 1, wherein receiving the transmission threshold from the remote network node comprises receiving a transmission threshold for multiple neighboring network nodes, and adjusting automatically the hardware settings of the local wireless network node based on the local transmission threshold and the received transmission threshold comprises adjusting the hardware settings of the local wireless network node based on the local transmission threshold and all received transmission thresholds.

6. A network element of a wireless network comprising:

a receiver to receive a carrier sensing signal sent from the network element to determine a physical carrier sense (PCS) characteristic of the network element, and to receive from a neighboring network element a signal indicating a PCS characteristic of the neighboring network element, where the received PCS characteristic of the neighboring network element indicates a threshold level of interference that is tolerable for a physical layer of the neighboring network element, where interference in the wireless network exceeding the received PCS characteristic of the neighboring network element causes the neighboring network element to back off from transmission;

a transmitter to transmit a PCS characteristic determined for the network element;

a processor coupled with the receiver and the transmitter, to process the received carrier sensing signal and determine a PCS characteristic for the network element based at least in part on the signal to noise ratio of the received carrier sensing signal, where the determined PCS characteristic of the network element indicates a threshold level of interference that is tolerable for a physical layer of the network element, where interference in the wireless network exceeding the determined PCS characteristic of the network element causes the network element to back off from transmission, and the processor to further determine an updated PCS characteristic for the network element based at least in part on the determined PCS characteristic for the network element and the received PCS characteristic of the neighboring network element, including determining which of the determined PCS characteristic for the network element or the received PCS characteristic for the neighboring network element is lower in value and selecting the lower value of the PCS characteristics as a value of the updated PCS characteristic; and

hardware control circuits to set the hardware PCS threshold of the network element to the value of the updated PCS characteristic, where interference in the wireless network exceeding the updated PCS characteristic causes the network element to back off from transmission.

7. A network element according to claim 6, wherein transmitter transmits the determined PCS characteristic to neighboring nodes in the wireless network.

8. A network element according to claim 6, wherein the receiver to receive the PCS characteristic from the neighboring network element comprises the receiver to receive transmission from a centralized control node that receives and distributes PCS characteristics for multiple nodes of the network.

9. A network element according to claim 6, wherein the hardware control circuitry sets the hardware PCS threshold at periodic intervals and does not alter the hardware PCS threshold setting during the interval.

10. A wireless electronic device comprising:

a wireless device hardware circuit having;

a processor to determine a hardware carrier sensing sensitivity level based at least in part on a carrier sensing level determined for the wireless electronic device based on an interference condition of a communication channel and a carrier sensing level received from a remote wireless electronic device in a network that produces interference on the communication channel, wherein the carrier sensing level determined for the wireless electronic device indicates a threshold level of interference that is tolerable for a physical layer of the wireless electronic device, where interference on the communication channel exceeding the threshold level indicated by the carrier sensing level determined for the wireless electronic device causes the wireless electronic device to back off from transmission on the communication channel, and wherein the received carrier sensing level for the remote wireless electronic device indicates a threshold level of interference that is tolerable for a physical layer of the remote wireless electronic device, where interference in the network exceeding the threshold level indicated by the received carrier sensing level for the remote wireless electronic device causes the remote wireless electronic device to back off from transmission; and

a control circuit to adjust the hardware carrier sensing sensitivity level to the determined level, where interference in the wireless network exceeding the updated PCS characteristic causes the network element to back off from transmission; and

a flash memory coupled with the chipset to store data from the processor and provide stored data to the processor.

11. A wireless electronic device according to claim 10, wherein the processor determines the carrier sensing level based at least in part on a carrier sensing threshold determined from a signal to noise ratio (SNR) for the communication channel for the wireless electronic device.

12. A wireless electronic device according to claim 10, wherein the control circuit adjusts the hardware carrier sensing sensitivity level at periodic intervals.

13. A wireless electronic device according to claim 10, wherein the hardware circuit further comprises a transmission control circuit to cause a wireless transmitter on the electronic device to transmit the determined carrier sensing sensitivity level to another electronic device in the network.

14. An article of manufacture comprising a machine-accessible storage medium having content stored thereon to provide instructions to cause an electronic system to:

measure a communication channel characteristic of a wireless communication channel for a local wireless network node of a network of nodes;

determine a local transmission threshold for the local wireless network node based on the measured communication channel characteristic, wherein the local transmission threshold includes a physical carrier sense threshold indicating a threshold level of interference that is tolerable for a physical layer of the local wireless network node, where interference sensed in the network by the local wireless network node exceeding the local transmission threshold causes the local wireless network node to back off from transmission;

receive a transmission threshold from a remote network node, the received transmission threshold indicating a threshold level of interference that is tolerable for a physical layer of the remote network node, where interference sensed in the network by the remote network node exceeding the received transmission threshold causes the remote network node to back off from transmission; and

adjust automatically the hardware settings of the physical layer of the local wireless network node based on the local transmission threshold and the received transmission threshold, including selecting the lower transmission threshold of the local transmission threshold and the received transmission threshold, and adjusting the hardware settings to make the wireless network node responsive to the selected transmission threshold, where interference exceeding the selected transmission threshold causes the local wireless network node to back off from transmission on the wireless communication channel.

15. An article of manufacture according to claim 14, wherein the content to provide instructions to cause the electronic device to measure the communication channel characteristic comprises the content to provide instructions to cause the electronic device to determine a signal to noise-plus-interference ratio (SNIR) for the communication channel for the local wireless network node.

16. An article of manufacture according to claim 14, wherein the content to provide instructions to cause the electronic device to determine a transmission threshold comprises the content to provide instructions to cause the electronic device to determine a physical carrier sense threshold.

17. An article of manufacture according to claim 14, further comprising the content to provide instructions to cause the electronic device to transmit the determined local transmission threshold to another node in the wireless network.

18. An article of manufacture according to claim 14, wherein the content provide instructions to cause the electronic device to adjust the hardware settings of the local wireless network node at periodic intervals.

19. An article of manufacture according to claim 14, wherein the content to provide instructions to cause the electronic device to receive the transmission threshold from the remote network node comprises the content to provide instructions to cause the electronic device to receive a transmission threshold for multiple neighboring network nodes, and wherein the content to provide instructions to cause the electronic device to adjust automatically the hardware settings of the local wireless network node based on the local transmission threshold and the received transmission threshold comprises the content to provide instructions to cause the electronic device to adjust the hardware settings of the local wireless network node based on the local transmission threshold and all received transmission thresholds.

20. An apparatus comprising:

a processor to determine a carrier sensing threshold for the apparatus based at least in part on interference associated with a communication channel of a transmission medium, including determining a physical carrier sense threshold for the apparatus indicating a threshold level of interference that is tolerable for a physical layer of the apparatus, where interference on the communication channel exceeding the threshold level causes the apparatus to back off from transmission on the communication channel, and based at least in part on a remote carrier sensing threshold of a remote wireless network device sent to the apparatus from the remote wireless network device, the remote carrier sensing threshold indicating a threshold level of interference that is tolerable for a physical layer of the remote wireless electronic device, where interference in the network exceeding the threshold level indicated by the remote carrier sensing level for the remote wireless electronic device causes the remote wireless electronic device to back off from transmission, wherein the determined carrier sensing threshold for the apparatus is selected as the lower of the physical carrier sense threshold for the apparatus and the remote carrier sense threshold for the remote wireless network device; and

a control circuit to adjust the carrier sensing threshold to the determined carrier sensing threshold to cause the apparatus to be responsive to the determined carrier sensing threshold, where interference exceeding the determined carrier sensing threshold causes the apparatus to back off from transmission on the communication channel.

21. An apparatus according to claim 20, wherein the processor to determine the carrier sensing threshold based on the interference further comprises the processor to determine a signal to noise ratio (SNR) for the communication channel.

22. An apparatus according to claim 20, further comprising the processor to prepare a message having the determined carrier sensing threshold to transmit to the remote wireless network device.

23. An apparatus according to claim 20, wherein the control circuit to adjust the carrier sensing threshold comprises the hardware control circuit to adjust the carrier sensing threshold at periodic intervals.