Granted Patent B2

US 8,750,167 · App. 13/284,253 · Granted Jun 10, 2014

Abstract

Claims (18)

1. A method of controlling transmit power of nodes in an ad-hoc network, comprising:

receiving, by a receiver of a leaf node included in the nodes of the ad-hoc network, a signal from a coordinator node included in the nodes of the ad-hoc network; and

setting, by the leaf node, a transmit power of a transmitter of the leaf node based on a level of the signal and a desired minimum sensitivity for the receiver, wherein the transmit power of the transmitter of the leaf node is set using the formula Ptx=max(min(Ptx,max,(Pbeacon−Pbeacon_rx)+Rx_min_sensitivity+Rx_SNRmin),Ptx,min), where Ptx,max is the maximum allowable transmit output power (dBm), Ptx,min is the minimum allowable transmit output power (dBm), Pbeacon is the transmitted power of the beacon signal, Pbeacon_rx is the transmitted power loss of the beacon signal at the receiver, Rx_min_sensitivity is the minimum receiver sensitivity, and Rx_SNRmin is the minimum signal-to-noise ratio (SNR) desired for a received signal.

2. The method of claim 1 , further comprising:

designating one of the nodes of the ad-hoc network to act as the coordinator node.

3. The method of claim 2 , wherein a first one of the nodes in the ad-hoc network that is powered-up is designated to act as the coordinator node.

4. The method of claim 1 , wherein the transmit power is changed in response to adding or deleting a node from the ad-hoc network.

5. A first network node of an ad-hoc network, comprising:

a receiver;

a transmitter; and

a control unit coupled to the receiver and the transmitter, wherein the control unit is configured to set a transmit power of the transmitter based on a level of a signal received by the receiver from a second network node of the ad-hoc network and a desired minimum signal-to-noise ratio for a received signal, wherein the first network node is a leaf node, the signal is a beacon signal transmitted from the second network node, and the second network node is a coordinator node, and wherein the transmit power of the transmitter of the leaf node is set using the formula Ptx=max(min(Ptx,max,(Pbeacon−Pbeacon_rx)+Rx_min_sensitivity+Rx_SNRmin),Ptx,min), where Ptx,max is the maximum allowable transmit output power (dBm), Ptx,min is the minimum allowable transmit output power (dBm), Pbeacon is the transmitted power of the beacon signal, Pbeacon_rx is the transmitted power loss of the beacon signal at the receiver, Rx_min_sensitivity is the minimum receiver sensitivity, and Rx_SNRmin is the minimum signal-to-noise ratio (SNR) desired for a received signal.

6. The first network node of claim 5 , wherein the second network node is a coordinator node and a first node of the ad-hoc network to power-up is designated to act as the coordinator node.

7. The first network node of claim 5 , wherein the transmit power is changed in response to adding or deleting a node from the ad-hoc network.

8. The first network node of claim 5 , wherein the signal is a beacon signal.

9. A leaf node of an ad-hoc network that includes multiple nodes, the leaf node comprising:

a receiver configured to receive a beacon signal from a coordinator node included in the multiple nodes; and

a transmitter that is configured to transmit at a transmit power set using the formula Ptx=max(min(Ptx,max,(Pbeacon−Pbeacon_rx)+Rx_min_sensitivity+Rx_SNRmin),Ptx,min), where Ptx,max is the maximum allowable transmit output power (dBm), Ptx,min is the minimum allowable transmit output power (dBm), Pbeacon is the transmitted power of the beacon signal, Pbeacon_rx is the transmitted power loss of the beacon signal at the receiver, Rx_min_sensitivity is the minimum receiver sensitivity, and Rx_SNRmin is the minimum signal-to-noise ratio (SNR) desired for a received signal.

10. The leaf node of claim 9 , wherein the transmit power is changed in response to replacing the coordinator node with another node included in the ad-hoc network.

Assignments (30)