Communication network optimization tool

• US 7,586,891 B1
• Filed: 12/08/2005
• Issued: 09/08/2009
• Est. Priority Date: 12/08/2005
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Masciulli, Michael
• Primary Examiner(s): Sheikh; Ayaz R
• Assistant Examiner(s): HALIYUR, VENKATESH N
• Application Number:
  US11/311,575
• Time in Patent Office: 1,370 Days
• Field of Search: 370229-503, 455295-522, 342/13
• US Class Current: 370/344
• CPC Class Codes: H04L 45/122 by minimising distances, e.g. by selecting a route with minimum of number of hops
• CPC Class Codes: H04L 45/124 using a combination of metrics
• CPC Class Codes: H04W 40/12 based on transmission quality or channel quality
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for converging on a route through a radio frequency (RF) communications network, that includes multiple nodes, includes (a) identifying all RF links between each node in the RF communications network; (b) determining a connectivity confidence interval for each RF link by: (aa) developing a calculated signal to noise ratio using a radio frequency communication link propagation loss model; (bb) determining a threshold signal to noise ratio based on a predetermined RF packet completion rate; (cc) determining a standard deviation value based on a signal strength and a noise level at a signal receiving node; (dd) calculating a Z number, associated with a normal distribution table which is based on the threshold signal to noise ratio minus the calculated signal to noise ratio with that result being divided by the standard deviation value; and (ee) assigning a CCI probability value based on said Z number. The method further comprises (c) setting a predetermined connectivity confidence interval minimum; (d) comparing each connectivity confidence interval for each RF link to the predetermined connectivity confidence interval minimum to determine which are greater than or equal to the predetermined connectivity confidence interval; (e) assembling each RF link corresponding to each connectivity confidence interval that is greater than or equal to the predetermined connectivity confidence interval together to identify various routes through the RF network; (f) calculating a resultant connectivity confidence interval for each route by multiplying together each connectivity confidence interval for each RF link of each particular route; and (g) comparing each resultant connectivity confidence interval to identify the route with the greatest resultant connectivity confidence interval. An apparatus for carrying out such a method is also presented.

Claims

1. A method for converging on a route through a multi-node digital radio frequency (RF) communications network, comprising the steps of:

identifying a plurality of RF links between each node in said digital RF communications network;

determining a connectivity confidence interval (CCI) probability, said CCI probability being a probability that a measured signal-to-noise ratio meets or exceeds a threshold signal-to-noise ratio thereby designating a level of favorable RF connectivity for each node in said plurality of RF links by;

developing a calculated signal to noise ratio using a radio frequency communication link propagation loss model;

determining said threshold signal-to-noise ratio based on a predetermined RF Packet Completion Rate and a sufficient time interval between a host transmission and a host reception;

determining a standard deviation value based on a signal strength and a noise level at a signal receiving node;

calculating a Z number, associated with a normal distribution table, according to the following equation;

Z=((S/N)_—

T−

(S/N)_CAL)/SD_(S/J))

where said (S/N)_T is the threshold signal-to-noise ratio, said (S/N)_CAL is the calculated signal-to-noise ratio, and said SD_(S/J) is the standard deviation value; and

assigning a CCI link probability value based on said Z number;

setting a predetermined CCI minimum threshold;

comparing said plurality of CCI link probability values to said predetermined CCI minimum threshold to identify a group of CCI link values greater than or equal to said predetermined CCI minimum threshold;

assembling a plurality of RF links corresponding to said group of CCI link values to establish a plurality of favorable link routes through said digital RF communications network;

calculating a resultant CCI link value for each of said plurality of link routes by multiplying together said group of CCI link values;

comparing said resultant CCI link values to identify a one of said plurality of link routes providing a maximum resultant CCI value;

comparing said resultant CCI link values to generate a first rank order of link routes from said maximum resultant CCI value to a least resultant CCI value;

totaling the number of nodes in each of said plurality of link routes to generate a second rank order of link routes having a least number of nodes to said maximum resultant CCI value with a greatest number of nodes; and

comparing said first rank order to said second rank order to determine which route provides said maximum resultant CCI value and a lowest number of nodes to converge on a shortest most reliable route, and generating an expected RF link Packet Completion Rate performance level based on said maximum resultant CCI value on said shortest most reliable route.

2. The method of claim 1, further comprising the step of calculating a second signal to noise ratio using a set of measured radio frequency communication link propagation loss values making a plurality of Packet Completion Rate measurements.

3. The method of claim 2, further comprising the steps of:

determining a standard deviation value based on a mode of propagation used in said propagation loss model, which, in turn, is based on a difference between a propagation loss calculation and a measured value of propagation loss; and

said radio frequency communication link propagation loss model comprises a Terrain-Integrated Rough-Earth Model (TIREM).

4. The method of claim 3, further comprising the step of:

identifying all RF links by identifying all possible permutations in said digital RF communication network.

5. The method of claim 4, wherein said predetermined RF Packet Completion Rate is in the range of between approximately 50% and approximately 100%.

6. The method of claim 5, wherein said predetermined RF Packet Completion Rate comprises 50%.

7. The method of claim 6, wherein said predetermined CCI minimum threshold is in the range of approximately 0.95 to approximately 1.00.

8. The method of claim 7, wherein said predetermined CCI minimum threshold is approximately 1.00.

9. The method of claim 8, further comprising the steps of:

sending a host message from a transmission host computer to a receiving host computer in said digital RF communications network, wherein said host message is contained in one RF packet, said transmission host computer is connected to a transmission router that is connected to a transmission radio; and

receiving said host message from said transmission radio with a receiving radio, said receiving radio being connected to a traffic receiver in a receiving host computer.

10. The method of claim 8, wherein said signal strength comprises a combination of power of said transmitter, an antenna gain of said transmitter, a cable loss of said transmitter, a propagation loss value from the transmitter to the receiver, an antenna gain of the receiver, and a cable loss of the receiver.

11. The method of claim 8, wherein said noise level comprises a combination of power of a jamming transmitter, an antenna gain of the jamming transmitter, a cable loss of jamming transmitter, a propagation loss value from said jamming transmitter to said receiver, an antenna gain of said receiver, a cable loss of said receiver, and a jammer bandwidth correction factor.

12. The method of claim 8, wherein:

an average measured signal-to-noise ratio is used instead of said threshold signal-to-noise ratio during said Z number calculating step;

said noise level comprises a predetermined background noise for rural, suburban, and urban environments.

13. An apparatus for converging on a route through a multi-node digital radio frequency (RF) communications network, comprising:

a means for identifying a plurality of RF links between each node in said digital RF communications network;

a means for determining a threshold signal-to-noise ratio;

a means for determining a connectivity confidence interval (CCI) probability, said CCI probability being a probability that a measured signal-to-noise ratio meets or exceeds said threshold signal-to-noise ratio thereby designating a level of favorable RF connectivity for each node in said plurality of RF links by;

a means for developing a calculated signal to noise ratio using a radio frequency communication link propagation loss model;

said threshold signal-to-noise ratio determining means being based on a predetermined RF Packet Completion Rate and a sufficient time interval between a host transmission and a host reception;

a means for determining a standard deviation value based on a signal strength and a noise level at a signal receiving node;

a means for calculating a Z number, associated with a normal distribution table according to the following equation;

Z=((S/N)_—

T−

(S/N)_CAL)/SD_(S/J))

where said (S/N)_T is the threshold signal-to-noise ratio, said (S/N)_CAL is the calculated signal-to-noise ratio, and said SD_(S/J) is the standard deviation value; and

a means for assigning a CCI link probability value based on said Z number;

a means for setting a predetermined CCI minimum threshold;

a means for comparing said plurality of CCI link probability values to said predetermined CCI minimum threshold to identify a group of CCI link values greater than or equal to said predetermined CCI minimum threshold;

a means for assembling a plurality of RF links corresponding to said group of CCI link values establishes a plurality of favorable link routes through said digital RF communications network;

a means for calculating a resultant CCI link value for each of said plurality of link routes multiplies together said group of CCI link values;

said comparison means compares said resultant CCI link values to identify a one of said plurality of link routes providing a maximum resultant CCI value and to generate a first rank order of link routes from said maximum resultant CCI value to a least resultant CCI value;

a means for totaling the number of nodes in each of said plurality of link routes generates a second rank order of link routes having a least number of nodes to said maximum resultant CCI value with a greatest number of nodes; and

said comparison means compares said first rank order to said second rank order to determine which route provides said maximum resultant CCI value and a lowest number of nodes to converge on a shortest most reliable route, and generates an expected RF link Packet Completion Rate performance level based on said maximum resultant CCI value on said shortest most reliable route.

14. The apparatus of claim 13, further comprising a means for calculating a second signal-to-noise ratio using a set of measured radio frequency communication link propagation loss values making a plurality of Packet Completion Rate measurements.

15. The apparatus of claim 14, further comprising said identifying RF links means having a means for identifying all possible permutations in said digital RF communication network.

16. The apparatus of claim 15, wherein said predetermined RF Packet Completion Rate is in the range of between approximately 50% and approximately 100%.

17. The apparatus of claim 16, wherein said predetermined CCI minimum threshold is in the range of approximately 0.95 to approximately 1.00.

18. The apparatus of claim 13, further comprising:

a host message being sent from a transmission host computer to a receiving host computer in said digital RF communications network;

said host message being contained in one RF packet;

said transmission host computer being connected to a transmission router that is connected to a transmission radio; and

said host message from said transmission radio being received by a receiving radio, said receiving radio being connected to a traffic receiver in a receiving host computer.

19. The apparatus of claim 17, wherein said signal strength comprises a combination of power of said transmitter, an antenna gain of said transmitter, a cable loss of said transmitter, a propagation loss value from the transmitter to the receiver, an antenna gain of the receiver, and a cable loss of the receiver.

20. The apparatus of claim 17, wherein said noise level comprises a combination of power of a jamming transmitter, an antenna gain of the jamming transmitter, a cable loss of jamming transmitter, a propagation loss value from said jamming transmitter to said receiver, an antenna gain of said receiver, a cable loss of said receiver, and a jammer bandwidth correction factor.

21. The apparatus of claim 17, wherein:

an average measured signal-to-noise ratio is used instead of said threshold signal-to-noise ratio by said Z number calculating means; and

said noise level comprises a predetermined background noise for rural, suburban, and urban environments.