Adaptive hybrid wireless and wired process control system and method

• US 8,509,081 B2
• Filed: 11/03/2010
• Issued: 08/13/2013
• Est. Priority Date: 05/01/2008
• Status: Active Grant

• Current Assignee: King Fahd University Of Petroleum And Minerals
• Original Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia), King Fahd University Of Petroleum And Minerals
• Inventors: Daraiseh, Abdelghani, Landolsi, Mohamed Adnan
• Primary Examiner(s): Rutkowski, Jeffrey M
• Assistant Examiner(s): FAYED, RASHA K
• Application Number:
  US12/938,432
• Publication Number:
  US 20110158098A1
• Time in Patent Office: 1,014 Days
• Field of Search: 709239-242, 370/224, 370/248, 370/351, 790240-241
• US Class Current: 370/235
• CPC Class Codes: H04L 45/124 using a combination of metrics
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/42 Centralised routing
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing

Abstract

A hybrid wired and wireless architecture for a process control system is disclosed that includes hierarchical adaptability and optimization capabilities. The system is arranged in three tiers, the first including a number of wireless end devices exchanging packets of data and/or instructions with the distributed control system, where each wireless end device is associated with one or more meters, remote terminal units, diagnostic devices, pumps, valves, sensors, or tank level measuring devices. The second tier includes a plurality of wireless routers, each including a memory that stores a routing table and a processor that routes packets. The third tier includes a master wireless gateway device operably connected to receive packets from and transmit packets to the distributed control system. The processor of each of the wireless routers routes packets across the tiers between the end devices and the wireless gateway devices based on the stored routing table.

Claims

1. A method of selecting paths in a process control and/or automation network, the process control and/or automation network including one or more wireless end devices for transmitting data and/or receiving data, and either one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or one or more wireless intermediate devices or one or more wireless gateway devices, wherein a source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the method of selecting paths comprising:

a. specifying a minimum reliability requirement for a selected source-destination pair;

b. specifying a minimum number of paths between the selected source-destination pair;

c. determining possible paths between the selected source-destination pair;

d. calculating the reliability of each of the possible paths, or an effective reliability of one or more groups of possible paths;

e. identifying one or more reliable paths, or one or more reliable groups of paths, by comparing the reliability of each of the possible paths or groups of possible paths with the specified minimum reliability requirements; and

f. assigning the minimum number of paths for the selected source-destination pair to a routing table from the identified reliable paths or the identified reliable group of paths, and discarding, or assigning as alternate paths to the routing table, identified reliable paths or identified reliable groups of paths that exceed the minimum number of paths;

wherein the wireless process control and/or automation network includes plural of the wireless intermediate devices grouped into intermediate field network sets and/or plural of the wireless gateway devices grouped into gateway field network sets, further wherein step (c) includes determining possible paths between a source-destination pair passing through a designated anchor packet selection device of a predetermined number of the field network sets, and

wherein the anchor packet selection device of each field network set further includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

2. The method of claim 1, wherein a plurality of usage classes are defined for wireless communication, step (a) specifies a set of minimum reliability requirements for each usage class, and step (b) specified a minimum number of paths for each usage class.

3. The method of claim 1, further comprising, if the minimum number of paths is not met in step (f),

i. adding additional paths or groups of paths to the routing table to boost reliability, throughput or minimize delay;

ii. improve the reliability of the weakest link through redundancy; and

/or

iii. use other radio frequency channels and/or hopping patterns.

4. The method of claim 1, further comprising specifying a number of alternate paths, and assigning the specified number of alternate paths for the source-destination pair to the routing table, wherein frames are routed through the specified number of alternate paths and the assigned minimum number of paths from step (f) only if degradation in performance is sensed in any of the links or devices in the source-destination path.

5. The method of claim 1, further comprising specifying a maximum allowable delay for a source-destination pair, and, prior to assigning in step (f), discarding any paths that exceed the maximum allowable delay even if the determined reliability of those paths meets the specified minimum reliability requirements as determined in step (e).

6. The method as in claim 2, further comprising specifying a maximum allowable delay for each usage class, and, prior to assigning in step (f), discarding any paths that exceed the maximum allowable delay for the usage class even if the determined reliability of those paths meets the specified minimum reliability requirements as determined in step (e).

7. The method of claim 1, further comprising specifying a maximum allowable throughput for a link represented as η

(L(x,y),max), prior to step (f), discarding paths that do not meet the condition η

(L(x,y))≦

η

(L(x,y),max) for all links y, where η

(L(x,y)) represents the throughput for the y-th link of the x-th path, even if the determined reliability of those paths meets the specified minimum reliability requirements as determined in step (e).

8. The method of claim 2, wherein routing is dynamically adjusted to allow assigned and alternative paths to pass a data frame irrespective of the usage class when a timeout occurs for that data frame, when the data frame is identified as a retransmitted data frame, or when the frame error probability for a link within an assigned path exceeds a specified threshold.

9. The method of claim 2, further comprising, during abnormal channel conditions, sending a control message to wireless intermediate devices and/or wireless gateway devices to route frames irrespective of the usage class.

10. The method of claim 1, which includes optimizing routes for a group of less than all selected source-destination pairs, and prioritizing the group of selected source-destination pairs through the assigned minimum number of paths or reserving the assigned minimum number of paths exclusively for the group of selected source-destination pairs.

11. The method of claim 1, wherein at least one of the field network sets has at least one junction box,

and wherein at least one of the wireless routers is configured for wired communication and wired to a junction box,

and wherein one of the wireless routers that is wired to a junction box is designated as an anchor packet selection device through which all traffic in that field network set is routed.

12. The method of claim 1, wherein at least some of the wireless routers in a field network set include a wireless router wired to a junction box which contain stored in their memories field network set information as to which wireless routers are wired to junction boxes and their respective performance characteristics, the wireless routers having field network set information further comprising a routing module that uses the field network set information to dynamically route packets within the field network set.

13. The method of claim 1, wherein at least some of the wireless routers in a field network set include a wireless router wired to a junction box, wherein field network sets including a wireless router wired to a junction box are wired to the central control room.

14. A method of selecting paths in a wireless process control and/or automation network, the wireless process control and/or automation network including one or more wireless end devices for transmitting data and/or receiving data, and either one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or one or more wireless intermediate devices or one or more wireless gateway devices, wherein a source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the method of selecting paths comprising:

a. designating a maximum allowable end-to-end delay for a selected source-destination pair;

b. determining possible paths between the selected source-destination pair;

c. calculating an end-to-end delay for one of the possible paths;

d. identifying an acceptable path by comparing the calculated end-to-end delay for the one of the possible paths with the maximum allowable end-to-end delay, wherein a path is deemed acceptable if the calculated end-to-end delay is equal to or less than the maximum allowable end-to-end delay;

e. assigning the acceptable path to a routing table; and

f. repeating steps (c)-(e) for each of the possible paths identified in step (b);

wherein the wireless process control and/or automation network includes plural of the wireless intermediate devices grouped into intermediate field network sets and/or plural of the wireless gateway devices grouped into gateway field network sets, further wherein step (b) includes determining possible paths between a source-destination pair passing through a designated anchor packet selection device of a predetermined number of the field network sets, and

wherein the anchor packet selection device of each field network set further includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

15. The method of claim 14, wherein at step (a), a minimum reliability requirement and a minimum number of paths is specified for the selected source-destination pair, the method further comprising,

calculating the reliability of each of the acceptable paths or a group of acceptable paths;

identifying one or more reliable paths, or a group of paths, by comparing the reliability of each of the acceptable paths or a group of acceptable paths with the specified minimum reliability requirements; and

assigning the minimum number of paths for the selected source-destination pair to a routing table from the identified reliable paths or a group of paths.

16. The method of claim 14, further comprising specifying a number of alternate paths, and assigning the specified number of alternate paths for the source-destination pair to the routing table, wherein frames are routed through the specified number of alternate paths and the assigned minimum number of paths only if degradation in performance is sensed in any of the links or devices in the source-destination path.

17. The method of claim 14, further comprising specifying a maximum allowable throughput for a link represented as η

(L(x,y),max), discarding paths that do not meet the condition η

(L(x,y))≦

η

(L(x,y),max) for all links y, where η

(L(x,y)) represents the throughput for the y-th link of the x-th path.

18. The method of claim 14, wherein a plurality of usage classes are provided for wireless communication, and step (a) designates a maximum allowable end-to-end delay for each usage class for the selected source-destination pair.

19. The method of claim 18, wherein, during abnormal channel conditions, sending a control message to wireless intermediate devices and/or wireless gateway devices to route frames irrespective of the usage class.

20. A method of selecting paths in a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or a tier of or one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein a source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the method of selecting paths comprising:

a. designating a maximum allowable tier delay for a selected source-destination pair and for each tier;

b. determining possible paths between the selected source-destination pair;

c. calculating a tier delay for a link or set of links within a selected one of the tiers for one of the possible paths;

d. identifying an acceptable link or set of links by comparison of the calculated tier delay for that link or set of links with the maximum allowable tier delay for the selected tier, wherein a link or set of links is deemed acceptable if the calculated tier delay is equal to or less than the maximum allowable tier delay for the selected tier;

e. repeating steps (c) and (d) for each tier of the one of the possible paths for the remaining tiers;

f. assigning the one of the possible paths for the selected source-destination pair to a routing table if all of the links or sets of links within the one of the possible paths are identified as acceptable; and

g. repeating steps (c)-(f) for each of the possible paths identified in step (b);

wherein the wireless process control and/or automation network includes plural of the wireless intermediate devices grouped into intermediate field network sets and/or plural of the wireless gateway devices grouped into gateway field network sets, further wherein step (b) includes determining possible paths between a source-destination pair passing though through a designated anchor packet selection device of a predetermined number of the field network sets, and

wherein the anchor packet selection device of each field network set further includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

21. The method of claim 20, wherein at step (a), a minimum reliability requirement and a minimum number of paths is specified for the selected source-destination pair, the method further comprising:

calculating the reliability of each of the acceptable paths or a group of acceptable paths;

identifying one or more reliable paths, or a group of paths, by comparing the reliability of each of the acceptable paths or a group of acceptable paths with the specified minimum reliability requirements; and

assigning the minimum number of paths for the selected source-destination pair to a routing table from the identified reliable paths or a group of paths.

22. The method of claim 21, further comprising specifying a number of alternate paths, and assigning the specified number of alternate paths for the source-destination pair to the routing table, wherein frames are routed through the specified number of alternate paths and the assigned minimum number of paths only if degradation in performance is sensed in any of the links or devices in the source-destination path.

23. The method of claim 20, further comprising

specifying a maximum allowable throughput for a link represented as η

(L(x,y),max),

and discarding paths that do not meet the condition η

(L(x,y))≦

η

(L(x,y),max) for all links y, where η

(L(x,y)) represents the throughput for the y-th link of the x-th path.

24. The method of claim 20, wherein a plurality of usage classes are defined for wireless communication, and step (a) designates a maximum allowable tier delay for each usage class for the selected source-destination pair.

25. The method of claim 24, wherein, during abnormal channel conditions, sending a control message to wireless intermediate devices and/or wireless gateway devices to route frames irrespective of the usage class.

26. A method of selecting paths in a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or a tier of or one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein a source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the method of selecting paths comprising:

a. designating a maximum allowable end-to-end delay and a maximum allowable tier delay for a selected source-destination pair and for each tier for a selected source-destination pair;

b. determining possible paths between the selected source-destination pair;

c. calculating an end-to-end delay for one of the possible paths;

d. identifying a potentially acceptable path by comparison of the calculated end-to-end delay for the one of the possible paths with the maximum allowable tier delay, wherein a path is deemed potentially acceptable if the calculated end-to-end delay is equal to or less than the maximum allowable end-to-end delay;

e. calculating a tier delay for a link or set of links within one of the tiers in the potentially acceptable path;

f. identifying an acceptable link or set of links within that one of the tiers by comparison of the calculated tier delay for that link or set of links with the maximum allowable tier delay for that one of the tiers, wherein a link or set of links is deemed acceptable if the calculated tier delay is equal to or less than the maximum allowable tier delay for that one of the tiers;

g. repeating steps (e) and (f) for a link or set of links within each tier of the potentially acceptable path;

h. assigning the potentially acceptable path for the selected source-destination pair to a routing table if all of the links or sets of links within the one of the possible paths are identified as acceptable; and

i. repeating steps (c)-(h) for each of the possible paths identified in step (b);

wherein the wireless process control and/or automation network includes plural of the wireless intermediate devices grouped into intermediate field network sets and/or plural of the wireless gateway devices grouped into gateway field network sets, further wherein step (b) includes determining possible paths between a source-destination pair passing through a designated anchor packet selection device of a predetermined number of the field network sets, and

wherein the anchor packet selection device of each field network set further includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

27. The method of claim 26, wherein at step (a), a minimum reliability requirement and a minimum number of paths is specified for the selected source-destination pair, the method further comprising,

calculating the reliability of each of the acceptable paths or a group of acceptable paths;

identifying one or more reliable paths, or a group of paths, by comparing the reliability of each of the acceptable paths or a group of acceptable paths with the specified minimum reliability requirements; and

assigning the minimum number of paths for the selected source-destination pair to a routing table from the identified reliable paths or a group of paths.

28. The method of claim 27, further comprising specifying a number of alternate paths, and assigning the specified number of alternate paths for the source-destination pair to the routing table, wherein frames are routed through the specified number of alternate paths and the assigned minimum number of paths only if degradation in performance is sensed in any of the links or devices in the source-destination path.

29. The method of claim 26, further comprising:

specifying a maximum allowable throughput for a link represented as η

(L(x,y),max),

and discarding paths that do not meet the condition η

(L(x,y))≦

η

(L(x,y),max) for all links y, where η

(L(x,y)) represents the throughput for the y-th link of the x-th path.

30. The method of claim 26, wherein a plurality of usage classes are provided for wireless communication, and step (a) designates a maximum allowable end-to-end delay and a maximum allowable tier delay for each usage class for the selected source-destination pair.

31. The method of claim 30, wherein, during abnormal channel conditions, sending a control message to wireless intermediate devices and/or wireless gateway devices to route frames irrespective of the usage class.

32. A method of integrating a wireless process control and/or automation network with a wired network comprising:

a. determining and selecting existing junction boxes for wired/wireless integration;

b. providing a plurality of wireless routers modified for wired connection;

c. installing the modified wireless routers and wiring them to the existing junction boxes selected for integration;

d. determining the number and size of field network sets including at least one modified wireless router and one or more of a wireless routers and/or junction boxes;

e. determining, for each source-destination pair and each field network set, an anchor modified wireless router through which all traffic for that source-destination pair is routed, wherein the anchor modified wireless router of each field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier;

f. determining the total number of paths per source-destination pairs per usage class (g);

g. setting a counter h;

h determining a set of paths is for the h^th source-destination pair per usage class, subject to one or more selected constraints including maximum tier delay, maximum end-to-end delay, maximum throughput, minimum link reliability level, required minimum reliability per usage class, CPU maximum usage level for the modified wireless router, the maximum number of links per path, or a combination of at least one of the foregoing constraints;

i. determining whether the set of paths meet all of the selected constraints;

j. incrementing h by 1 if the constraints are met;

k. assigning the set of paths is assigned for the source-destination pair per usage class of h=g.

33. A communication path optimization system for controlling a wireless process control and/or automation network, the wireless process control and/or automation network including one or more wireless end devices for transmitting data and/or receiving data, and either one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or one or more wireless intermediate devices or one or more wireless gateway devices, wherein at least one source-destination pair includes plural links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the communication path optimization system comprising:

a memory that stores

a set of routing rules specifying a minimum reliability requirement for a selected source-destination pair and

a specified minimum number of paths between the selected source-destination pair;

a processor coupled to the memory; and

a route optimization module executable by the processor and operable to transmit assigned reliable paths resulting from execution of the route optimization module to a routing table for instructing at least one of the one or more wireless gateway devices and/or the wireless intermediate devices, the route optimization module including;

a path determination sub-module for determination of possible paths between the selected source-destination pair;

a reliability calculation sub-module for calculation of the reliability of each of the possible paths, or an effective reliability of one or more groups of possible paths;

a reliable path identification sub-module for identification of one or more reliable paths, or a one or more reliable groups of paths, by comparing the reliability of each of the possible paths or groups of possible paths with the specified minimum reliability requirements specified in the set of routing rules; and

a path assignment sub-module for assignment of the minimum number of paths specified in the set of routing rules for the selected source-destination pair to the routing table from the identified reliable paths or the identified reliable groups of paths, and discarding, or assigning as alternate paths to the routing table, identified reliable paths or identified reliable groups of paths that exceed the minimum number of paths;

wherein the path determination sub-module is for determination of possible paths between the selected source-destination pair passing through a designated anchor point in a defined field network set, and

wherein the designated anchor point of each field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

34. The communication path optimization system of claim 33, wherein the processor that executes the route optimization module resides in a wireless gateway device.

35. The communication path optimization system of claim 34, in which the wireless process control and/or automation network includes a plurality of wireless gateway devices, wherein the wireless gateway device that executes the route optimization module is a master wireless gateway device.

36. The communication path optimization system of claim 33, wherein the processor that executes the route optimization module resides in a computing device separate from a wireless gateway device.

37. A communication path optimization system for controlling a wireless process control and/or automation network, the wireless process control and/or automation network including one or more wireless end devices for transmitting data and/or receiving data, and either one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and one or more wireless gateway devices for assigning data paths, or transmitting data, receiving data and routing received data, or one or more wireless intermediate devices or one or more wireless gateway devices, wherein at least one source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the communication path optimization system comprising:

a memory that stores

a set of routing rules specifying a maximum allowable end-to-end delay for a selected source-destination pair;

a processor coupled to the memory; and

an end-to-end delay minimization module executable by the processor and operable to transmit assigned acceptable paths resulting from execution of the end-to-end delay minimization module to a routing table for instructing at least one of the one or more wireless gateway devices and/or the wireless intermediate devices, the end-to-end delay minimization module including;

a path determination sub-module for determination of possible paths between the selected source-destination pair;

an end-to-end delay calculation sub-module for calculation of an end-to-end delay for one of the possible paths;

a path identification sub-module for identification of an acceptable path by comparing the calculated end-to-end delay for the one of the possible paths with the maximum allowable end-to-end delay, wherein a path is deemed acceptable if the calculated end-to-end delay is equal to or less than the maximum allowable end-to-end delay; and

a path assignment sub-module for assignment of the acceptable path to the routing table,

wherein the end-to-end delay calculation sub-module, the path identification sub-module and the path assignment sub-module are executed for each of the possible paths identified in the path determination sub-module;

wherein the path determination sub-module is for determination of possible paths between the selected source-destination pair passing through a designated anchor point in a defined field network set, and

wherein the designated anchor point of each field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

38. A communication path optimization system for controlling a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data, and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or a tier of one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein at least one source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the communication path optimization system comprising:

a memory that stores

a set of routing rules specifying a maximum allowable tier delay for a selected source-destination pair;

a processor coupled to the memory; and

a tier delay minimization module executable by the processor and operable to transmit assigned acceptable paths resulting from execution of the tier delay minimization module to a routing table for instructing at least one of the one or more wireless gateway devices and/or the wireless intermediate devices, the tier delay minimization module including;

a path determination sub-module for determination of possible paths between the selected source-destination pair;

a tier delay calculation sub-module for calculation of an end-to-end delay for one of the possible paths;

a link identification sub-module for identification of an acceptable link or set of links by comparison of the calculated tier delay for that link or set of links with the maximum allowable tier delay for that one of the tiers, wherein a link or set of links is deemed acceptable if the calculated tier delay is equal to or less than the maximum allowable tier delay for that one of the tiers; and

a path assignment sub-module for assignment of an acceptable path to the routing table,

wherein the tier delay calculation sub-module and the link identification sub-module are executed for each tier of the one of the possible paths, and

wherein the tier delay calculation sub-module, the link identification sub-module and the path assignment sub-module are executed for each of the possible paths identified in the path determination sub-module;

wherein the path determination sub-module is for determination of possible paths between the selected source-destination pair passing through a designated anchor point in a defined field network set, and

wherein the designated anchor point of each field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

39. A communication path optimization system for controlling a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or a tier of one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein at least one source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the communication path optimization system comprising:

a memory that stores

a set of routing rules specifying a maximum allowable tier delay and a maximum allowable end-to-end delay for a selected source-destination pair;

a processor coupled to the memory; and

a path determination module for determination of possible paths between the selected source-destination pair;

an end-to-end delay minimization module executable by the processor and operable to identify potential acceptable paths resulting from execution of the end-to-end delay minimization module, the end-to-end delay minimization module including;

an end-to-end delay calculation sub-module for calculation of an end-to-end delay for one of the possible paths;

a path identification sub-module for identification of a potentially acceptable path by comparing the calculated end-to-end delay for the one of the possible paths with the maximum allowable end-to-end delay, wherein a path is deemed potentially acceptable if the calculated end-to-end delay is equal to or less than the maximum allowable end-to-end delay; and

a tier delay minimization module executable by the processor and operable to transmit assigned acceptable paths resulting from execution of the tier delay minimization module to a routing table for instructing at least one of the one or more wireless gateway devices and/or the wireless intermediate devices, the tier delay minimization module including;

a tier delay calculation sub-module for calculation of an end-to-end delay for one of the potentially acceptable paths;

a link identification sub-module for identification of an acceptable link or set of links by comparison of the calculated tier delay for that link or set of links with the maximum allowable tier delay for that one of the tiers, wherein a link or set of links is deemed acceptable if the calculated tier delay is equal to or less than the maximum allowable tier delay for that one of the tiers; and

a path assignment sub-module for assignment of an acceptable path to the routing table,

wherein the tier delay calculation sub-module and the link identification sub-module are executed for each tier of the potentially acceptable paths, and

wherein the end-to-end delay minimization module and tier delay minimization module are executed for each of the possible paths identified in the path determination module;

wherein the path determination sub-module is for determination of possible paths between the selected source-destination pair passing through a designated anchor point in a defined field network set, and

wherein the designated anchor point of each field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

40. A communication path optimization system for controlling a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, or a tier of one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein at least one source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the communication path optimization system comprising:

a memory that stores

a set of routing rules specifying a maximum allowable tier delay and a maximum allowable end-to-end delay for a selected source-destination pair;

a processor coupled to the memory; and

a path determination module for determination of possible paths between the selected source-destination pair passing through a designated anchor packet selection device of a field network set, the field network set including a group of wireless intermediate devices and/or wireless gateway devices, wherein the designated anchor packet selection device of the field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier;

an end-to-end delay minimization module executable by the processor and operable to identify potential acceptable paths resulting from execution of the end-to-end delay minimization module, the end-to-end delay minimization module including;

an end-to-end delay calculation sub-module for calculation of an end-to-end delay for one of the possible paths;

a path identification sub-module for identification of a potentially acceptable path by comparing the calculated end-to-end delay for the one of the possible paths with the maximum allowable end-to-end delay, wherein a path is deemed potentially acceptable if the calculated end-to-end delay is equal to or less than the maximum allowable end-to-end delay; and

a tier delay minimization module executable by the processor and operable to transmit assigned acceptable paths resulting from execution of the tier delay minimization module to a routing table for instructing at least one of the one or more wireless gateway devices and/or the wireless intermediate devices, the tier delay minimization module including;

a tier delay calculation sub-module for calculation of an end-to-end delay for one of the potentially acceptable paths;

a link identification sub-module for identification of an acceptable link or set of links by comparison of the calculated tier delay for that link or set of links with the maximum allowable tier delay for that one of the tiers, wherein a link or set of links is deemed acceptable if the calculated tier delay is equal to or less than the maximum allowable tier delay for that one of the tiers; and

a path assignment sub-module for assignment of an acceptable path to the routing table,

wherein the tier delay calculation sub-module and the link identification sub-module are executed for each tier of the potentially acceptable paths, and

wherein the end-to-end delay minimization module and tier delay minimization module are executed for each of the possible paths identified in the path determination module.

41. A method of selecting paths in a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, a tier of or one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein a source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the method of selecting paths comprising:

a. determining possible paths between a selected source-destination pair;

b. identifying one or more reliable paths, or one or more reliable groups of paths, by comparing the reliability of each of the possible paths or groups of possible paths with a specified minimum reliability requirement;

c. identifying a potentially acceptable path by comparison of a calculated end-to-end delay for the one of the possible paths with a maximum allowable tier delay, wherein a path is deemed potentially acceptable if the calculated end-to-end delay is equal to or less than the maximum allowable end-to-end delay;

d. identifying an acceptable link or set of links by comparison of a calculated tier delay for a selected link or set of links with a maximum allowable tier delay for a selected tier, wherein a link or set of links is deemed acceptable if the calculated tier delay is equal to or less than the maximum allowable tier delay for that one of the tiers; and

e. assigning the potentially acceptable path for the selected source-destination pair to a routing table if all of the links or sets of links within the one of the possible paths are identified as acceptable in step (d) and if the potentially acceptable path is identified as reliable in step (b);

wherein the wireless process control and/or automation network includes plural of the wireless intermediate devices grouped into intermediate field network sets and/or plural of the wireless gateway devices grouped into gateway field network sets, further wherein step (a) includes determining possible paths between a source-destination pair passing through a designated anchor packet selection device of a predetermined number of the field network sets, and

wherein the designated anchor packet selection device of each field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier.

42. A communication path optimization system for controlling a wireless process control and/or automation network, the wireless process control and/or automation network including a tier of one or more wireless end devices for transmitting data and/or receiving data, and either a tier of one or more wireless intermediate devices for transmitting data and/or receiving data and routing received data, and a tier of one or more wireless gateway devices for assigning data paths, transmitting data, receiving data and routing received data, a tier of one or more wireless intermediate devices or a tier of one or more wireless gateway devices, wherein at least one source-destination pair includes links between the one or more wireless end devices, and the one or more wireless intermediate devices and/or the one or more wireless gateway devices, the communication path optimization system comprising:

a memory that stores

a set of routing rules specifying a minimum reliability requirement for a selected source-destination pair,

a specified minimum number of paths between the selected source-destination pair

a set of routing rules specifying a maximum allowable tier delay and a maximum allowable end-to-end delay for a selected source-destination pair, and

a routing table containing instructions to be processed by at least one of the one or more wireless gateway devices and/or the wireless intermediate devices;

a processor coupled to the memory;

a path determination module for determination of possible paths between the selected source-destination pair passing through a designated anchor packet selection device of a field network set, the field network set including a group of wireless intermediate devices and/or wireless gateway devices, wherein the designated anchor packet selection device of the field network set includes a processor and a packet selection module executable by the processor to select a packet among plural packets of the same information with the highest quality for retransmission to the next tier;

a route optimization module executable by the processor and operable to identify reliable paths between the selected source-destination pair;

an end-to-end delay minimization module executable by the processor and operable to identify potential acceptable paths that have a calculated end-to-end delay which is equal to or less than a maximum allowable end-to-end delay; and

a tier delay minimization module executable by the processor and operable to identify potential acceptable links or sets of links by comparison of a calculated tier delay for a selected link or set of links with a maximum allowable tier delay for a selected tier;

wherein the potentially acceptable path for the selected source-destination pair is assigned to the routing table stored in the memory if all of the links or sets of links within the one of the possible paths are identified by the tier delay minimization module and the route optimization module, and

wherein the end-to-end delay minimization module and tier delay minimization module are executed for each of the possible paths identified in the path determination module.