Receiving data in a sensor network

• US 8,130,669 B2
• Filed: 03/03/2010
• Issued: 03/06/2012
• Est. Priority Date: 04/26/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Radunovic, Bozidar, Truong, Hong Linh
• Primary Examiner(s): Ferris, Derrick
• Assistant Examiner(s): YEUNG, MANG HANG
• Application Number:
  US12/716,716
• Publication Number:
  US 20100157862A1
• Time in Patent Office: 734 Days
• Field of Search: 370/230, 370/229, 370/252
• US Class Current: 370/252
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A sensor network has a plurality of wireless sensors which transmit to an intermediate receiving device which relays data to a central server. A method is provided for receiving data packets at the intermediate receiving device from a plurality of the transmitting devices. Data packets are sensed on a communication medium at the receiving device and the total traffic intensity of data packets from the transmitting devices is estimated. A detection threshold for data packets is provided and adapted as a function of the total intensity. The receiving device receives data packets with a signal strength above the current detection threshold.

Claims

1. A method for receiving data packets from a plurality of transmitting devices at a receiving device, comprising:

sensing data packets transmitted on a communication medium;

estimating a total traffic intensity of data packets generated by the transmitting devices;

defining a detection threshold for receiving data packets as a function of the total traffic intensity;

ignoring data packets with a received signal strength below the detection threshold; and

receiving data packets with a received signal strength above the detection threshold;

wherein when the total traffic intensity is low, the detection threshold is decreased;

wherein when the total traffic intensity increases, the detection threshold is increased;

wherein the detection threshold is defined for every data packet sensed;

wherein the method includes estimating a utilization at the receiving device and defining the detection threshold to maximize the utilization;

wherein the traffic intensity is estimated by a packet duration divided by an average idle time at the receiving device;

wherein the utilization at the receiving device is estimated by a packet duration divided by an average time between two successful packet receptions;

wherein the total traffic intensity and the utilization are continually updated;

wherein the method includes maintaining a list of active transmitting devices and their received signal strengths;

wherein the total traffic intensity is maintained at about 75% of the physical layer data rate and the utilization is maintained at about 22%; and

wherein the detection threshold is increased if it is detected a predetermined number of times in succession that the total traffic intensity is greater than 75% and the utilization is less than 22%, and wherein the detection threshold is decreased if the total traffic intensity is less than 75% and the utilization is less than 22%.