Multi-hop power management in a wireless mesh network

• US 10,609,620 B1
• Filed: 01/08/2018
• Issued: 03/31/2020
• Est. Priority Date: 01/08/2018
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Wong, Chiu Ngok Eric, Liu, Jungtao
• Primary Examiner(s): Vu, Hoang-Chuong Q
• Application Number:
  US15/864,943
• Time in Patent Office: 813 Days
• CPC Class Codes: H04L 45/122 by minimising distances, e.g. by selecting a route with minimum of number of hops
• CPC Class Codes: H04W 40/08 based on transmission power
• CPC Class Codes: H04W 40/16 based on interference
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Technology for multi-hop power management is described. In one embodiment, processing logic obtains a noise floor value, an interference threshold parameter, a data rate threshold parameter, and a set of channel interference metrics from each of a first mesh network device, a second mesh network device, and a third mesh network device, respectively. The processing logic identifies a network path that traverses the three mesh network devices. The processing logic calculates a first transmit power level for the first mesh network device, a second transmit power level for the second mesh network device, and a third transmit power level for the third mesh network device. Data transmissions by each of the mesh network device at the respective transmit power levels ensure a minimum data transmission rate over each hop of the network path.

Claims

1. A mesh network device deployed in a wireless mesh network (WMN), the mesh network device comprising:

a first radio coupled to an omnidirectional antenna;

a second radio selectively coupled to any one of a plurality of directional antennas;

a third radio selectively coupled to any one of the plurality of directional antennas;

an application processor coupled to the first radio, the second radio, and the third radio, wherein the application processor;

stores a first interference threshold parameter indicative of an amount of acceptable radio-frequency interference at the mesh network device;

stores a first signal-to-interference-plus-noise ratio (SINR) threshold parameter indicative of an acceptable data transmission rate for the mesh network device;

measures radio-frequency (RF) noise samples using at least one of the first radio, the second radio, and the third radio, during a pre-determined period of no-activity in the WMN, the RF noise samples are indicative of RF power measured at the at least one of the first radio, the second radio, and the third radio at a specified frequency;

estimates a first noise floor value from the RF noise samples;

determines a first path loss value (G_1,2) for a first communication channel between the second radio and a radio of a second mesh network device, wherein the first path loss value (G_1,2) is indicative of a first amount of interference affecting transmissions on the first communication channel;

determines a second path loss value (G_1,3) for a second communication channel between the third radio and a radio of a third mesh network device, wherein the second path loss value (G_1,3) is indicative of a second amount of interference affecting transmissions on the second communication channel, wherein the first amount of interference and the second amount of interference form a first set of interference metrics for the mesh network device;

obtains, from the second mesh network device, second data comprising a second noise floor value for the second mesh network device, a second set of interference metrics for the second mesh network device, a second interference threshold parameter for the second mesh network device, and a second SINR threshold parameter for the second mesh network device;

obtains, from the third mesh network device, third data comprising a third noise floor value for the second mesh network device, a third set of interference metrics for the third mesh network device, a third interference threshold parameter for the third mesh network device, and a third SINR threshold parameter for the third mesh network device; and

calculates a first transmit power level for the mesh network device, a second transmit power level for the second mesh network device, and a third transmit power level for the third mesh network device that results in a minimum data transmission rate of data transmissions over each hop of a network path that traverses the mesh network device, the second mesh network device, and the third mesh network device, wherein the application processor calculates the first transmit power, the second transmit power level, and the third transmit power level using the first noise floor value, the first set of interference metrics, the first interference threshold parameter, the first SINR threshold parameter, the second data, and the third data;

sends information that represents the second transmit power level to the second mesh network device via the second radio; and

sends information that represents the third transmit power level to the third mesh network device via the third radio.

2. The mesh network device of claim 1, further comprising a fourth radio selectively coupled to any one of the plurality of directional antennas, wherein the application processor further:

determines a third path loss value for a third communication channel between the fourth radio and a radio of a fourth mesh network device, wherein the third path loss value is indicative of a third amount of interference of affecting transmissions on the third communication channel;

obtains, from the fourth mesh network device, a fourth noise floor value for the fourth mesh network device, a fourth set of interference metrics for the fourth mesh network device, a fourth interference threshold parameter for the fourth mesh network device, and a fourth SINR threshold parameter for the fourth mesh network device; and

calculates the first transmit power level, the second transmit power level, the third transmit power level, and a fourth transmit power level for the fourth mesh network device that results in a uniform data transmission rate of data transmissions over a network path that traverses the mesh network device, the second mesh network device, the third mesh network device, and the fourth mesh network device.

3. The mesh network device of claim 1, wherein the application processor further:

transmits, using the second radio with a maximum transmit power level, a first set of frames over the first communication channel;

receives, by the second radio, a second set of frames over the first communication channel, wherein each of the second set of frames comprises an informational element identifying the maximum transmit power level used by the radio of the second mesh network device to transmit the second set of frames;

measures a receive signal strength indicator (RSSI) value for the first communication channel; and

determines the first path loss value by dividing the RSSI value by the maximum transmit power level.

4. A method comprising:

obtaining, from a first mesh network device, first data, the first data comprising a first noise floor value, a first interference threshold parameter, a first data rate threshold parameter, and a first set of channel interference metrics;

obtaining, from a second mesh network device, second data, the second data comprising a second noise floor value, a second interference threshold parameter, a second data rate threshold parameter, and a second set of channel interference metrics;

obtaining, from a third mesh network device, third data, the third data comprising a third noise floor value, a third interference threshold parameter, a third data rate threshold parameter, and a third set of channel interference metrics;

identifying a network path that traverses the first mesh network device, the second mesh network device, and the third mesh network device; and

calculating a first transmit power level for the first mesh network device, a second transmit power level for the second mesh network device, and a third transmit power level for the third mesh network device using the first data, the second data, and the third data, wherein transmitting data by each of the first mesh network device at the first transmit power level, the second mesh network device at the second transmit power level, and the third mesh network device at the third transmit power level ensures at least a specified minimum data rate over each hop in the network path.

5. The method of claim 4, wherein the obtaining, the identifying, and the calculating are performed by a mesh network control service, and wherein the method further comprises:

sending, by the mesh network control service, information that represents the first transmit power level to the first mesh network device;

sending, by the mesh network control service, information that represents the second transmit power level to the second mesh network device; and

sending, by the mesh network control service, information that represents the third transmit power level to the third mesh network device.

6. The method of claim 4, wherein the obtaining, the identifying, and the calculating are performed by the first mesh network device, and wherein the method further comprises:

transmitting, using a radio of the first mesh network device, first data at the first transmit power level; and

receiving, by a radio of the first mesh network device, second data from the second mesh network device.

7. The method of claim 4, wherein the obtaining, the identifying, and the calculating are performed by the first mesh network device, and wherein the method further comprises

measuring noise samples using one or more radios of the first mesh network device during a pre-determined period of no-activity;

filtering the noise samples to obtained filtered samples; and

computing an average value of the filtered samples to obtain the first noise floor value.

8. The method of claim 7, wherein the obtaining the first set of channel interference metrics comprises:

determining a first path loss value for a first communication channel between a first radio of the first mesh network device and a radio of the second mesh network device, wherein the first path loss value is indicative of a first interference level of the first communication channel; and

determining a second path loss value for a second communication channel between a second radio of the first mesh network device and a radio of the third mesh network device, wherein the second path loss value is indicative of a second interference level of the second communication channel.

9. The method of claim 4, wherein the first data rate threshold parameter is a distribution function of a signal-to-interference-plus-noise ratio (SINR) or a distribution function of a frequency distribution model.

10. The method of claim 4, wherein the obtaining, the identifying, and the calculating are performed by the first mesh network device, and wherein the obtaining the first set of channel interference metrics comprises:

receiving, by a radio of the first mesh network device, a frame over a first communication channel between the radio and a radio of the second mesh network device, wherein the frame includes information that represents a transmit power level used by the radio of the second mesh network device to transmit the frame;

measuring a receive signal strength indicator (RSSI) value for the first communication channel; and

determining a first path loss value using the transmit power level and the RSSI value, wherein the first path loss value is one of the first set of channel interference metrics.

11. The method of claim 4, wherein the obtaining, the identifying, and the calculating are performed by the first mesh network device, and wherein the obtaining the first set of channel interference metrics comprises:

receiving, by a radio of the first mesh network device, a frame over a first communication channel between the radio and a radio of the second mesh network device;

measuring a receive signal strength indicator (RSSI) value for the first communication channel;

correlating the RSSI value with a transmit power level associated with a transmitter media access control (MAC) address of the radio of the second mesh network device; and

determining a first path loss value using the transmit power level and the RSSI value, wherein the first path loss value is one of the first set of channel interference metrics.

12. The method of claim 4, wherein the obtaining, the identifying, and the calculating are performed by a mesh network control service, and wherein the obtaining the first set of channel interference metrics comprises:

scheduling first data transmissions by the first mesh network device in a first time slot;

scheduling second data transmissions by the second mesh network device in a second time slot; and

scheduling third data transmissions by the third mesh network device in a third time slot.

13. A computer system, comprising:

a memory to store instructions of a power manager; and

a processor coupled to the memory, wherein the processor to;

obtain first data comprising a first interference threshold parameter, a first data rate threshold parameter, and a first set of channel interference metrics from a first mesh network device;

obtain second data comprising a second interference threshold parameter, a second data rate threshold parameter, and a second set of channel interference metrics from a second mesh network device;

obtain third data comprising a third interference threshold parameter, a third data rate threshold parameter, and a third set of channel interference metrics from a third mesh network device;

identify a network path that traverses the first mesh network device, the second mesh network device, and the third mesh network device;

calculate a first transmit power level for the first mesh network device, a second transmit power level for the second mesh network device, and a third transmit power level for the third mesh network device using the first data, the second data, and the third data; and

send information that represents the first transmit power level to the first mesh network device, information that represents the second transmit power level to the second mesh network device, and information that represents the third transmit power level to the third mesh network device, wherein data transmissions by each of the first mesh network device at the first transmit power level, the second mesh network device at the second transmit power level, and the third mesh network device at the third transmit power level ensure a minimum data rate over each hop in the network path.

14. The computer system of claim 13, wherein the processor is further to:

schedule first data transmissions by the first mesh network device in a first time slot;

schedule second data transmissions by the second mesh network device in a second time slot; and

schedule third data transmissions by the third mesh network device in a third time slot.

15. The computer system of claim 13, wherein the first data rate threshold parameter is a signal-to-interference-plus-noise ratio (SINR) value.

16. The computer system of claim 13, wherein the first data rate threshold parameter is a distribution function of a signal-to-interference-plus-noise ratio (SINR).

17. The computer system of claim 13, wherein the first data rate threshold parameter is a distribution function of a frequency distribution model.

18. The computer system of claim 13, wherein the first set of channel interference metrics comprises a first path loss value corresponding to a first communication channel between a radio of the first mesh network device and a radio of the second mesh network device, wherein the first set of channel interference metrics comprises a second path loss value corresponding to a second communication channel between a radio of the first mesh network device and a radio of the third mesh network device.

19. The computer system of claim 13, wherein the first set of channel interference metrics are path loss values, wherein the second set of channel interference metrics are path loss values, and wherein the third set of channel interference metrics are path loss values.

20. The computer system of claim 13, wherein the processor is further to:

obtain a fourth interference threshold parameter, a fourth data rate threshold parameter, and a fourth set of channel interference metrics from a fourth mesh network device;

identify a second network path that traverses the first mesh network device, the second mesh network device, the third mesh network device, and the fourth mesh network device;

calculate the first transmit power level for the first mesh network device, the second transmit power level for the second mesh network device, the third transmit power level for the third mesh network device, and a fourth transmit power level for the fourth mesh network device; and

send information that represents the first transmit power level to the first mesh network device, information that represents the second transmit power level to the second mesh network device, information that represents the third transmit power level to the third mesh network device, and information that represents the fourth transmit power level to the fourth mesh network device, wherein data transmissions by each of the first mesh network device at the first transmit power level, the second mesh network device at the second transmit power level, the third mesh network device at the third transmit power level, and the fourth mesh network device at the fourth transmit power level ensure a minimum data rate over each hop in the second network path.