Private network link verification procedure in free space optical communication network

• US 20020054413A1
• Filed: 09/07/2001
• Published: 05/09/2002
• Est. Priority Date: 10/05/2000
• Status: Active Grant

• Current Assignee: ThinkLogix, LLC (Ascend Innovation Management, LLC)
• Original Assignee: Kiribati Wireless Ventures LLC (Intellectual Ventures LLC)
• Inventors: Shivnan, Aine
• Granted Patent: US 7,079,551 B2
• Time in Patent Office: Days
• US Class Current: 398/121
• CPC Class Codes: H04B 10/1149 Arrangements for indoor wireless networking of information
• CPC Class Codes: H04Q 11/0062 Network aspects
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring
• CPC Class Codes: H04Q 2011/0086 Network resource allocation, dimensioning or optimisation
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

A system and method for verifying the integrity of a communication link in a wireless optical communication network. The system and method include monitoring the communication link on at least two levels and enabling or disabling signaling over the communication link appropriately depending on events reported through the system.

Claims

1. A node for use in a freespace optical communication network, said node comprising:

a plurality of node heads, wherein each node head comprises an optical receiver and an optical transmitter; and

a node base, coupled with said plurality of node heads, said node base comprising a control processor and a data transport mechanism switch, coupled to said control processor and said plurality of node heads, wherein said control processor includes a link verification module for monitoring and verifying the status of a communication link between nodes in said network.

2. The node of claim 1, wherein said control processor further comprises:

a physical layer task configured to monitor a physical layer;

a physical layer interrupt service routine configured to control said physical layer task and reporting physical layer events to said link verification module;

a transceiver task configured to monitor said second state variable;

a link maintenance protocol configured to receive reporting of transceiver events via said transceiver task; and

a transceiver manager task module configured to report transceiver layer events to said link verification module.

3. The node of claim 2, wherein a first state variable is configured to indicate the status of said physical layer to said physical layer task, and a second state variable is configured to indicate the status of said transceiver layer to said transceiver task.

4. A control processor for use in a wireless communication node, wherein the node is one of a plurality of nodes in a wireless optical communication network and comprises a physical layer and a transceiver layer, said control processor comprising:

a link verification module for monitoring and verifying the status of a communication link;

a physical layer task module for monitoring said physical layer and reporting changes in said first state variable;

a physical layer interrupt service routine for controlling said physical layer task and reporting physical layer events to said link verification module;

a transceiver task module for monitoring said transceiver layer and reporting changes in said second state variable;

a link maintenance node protocol module for receiving reporting of transceiver events via said transceiver task; and

a transceiver manager task module for reporting transceiver events to said link verification module.

5. A method for verifying the status of a communication link in a wireless communication network having a plurality of nodes with optical communication links therebetween, wherein the optical communication link is implemented using an optical receiver/transmitter pair, the receiver/transmitter pair having a physical layer and a receiver/transmitter layer, the method comprising:

checking the status of said receiver/transmitter layer for changes in the status of said communication link at said receiver/transmitter layer; and

if said checking results in a link-up status

notifying a link verification module of said link up status;

checking the status of said physical layer for stability via a physical layer link up procedure; and

enabling network signaling over said communication link if said physical layer is stable.

6. In a wireless communication network having a plurality of nodes with communication links therebetween, wherein the communication link is implemented using a receiver/transmitter pair, the receiver/transmitter pair having a physical layer and a receiver/transmitter layer, a method for verifying the status of the communication link, comprising:

checking the status of said receiver/transmitter layer for changes in the status of said communication link at said receiver/transmitter layer; and

if said checking results in a link down status

notifying a link verification module of said link down status;

disabling network signaling over said communication link.

7. The method of claim 6, further comprising allowing at least one handshake attempt for said receiver/transmitter layer before notifying said link verification module.

8. A method for verifying the status of a communication link in a wireless communication network having a plurality of nodes with optical communication links therebetween, wherein the optical communication link is implemented using an optical receiver/transmitter pair, the receiver/transmitter pair having a physical layer and a receiver/transmitter layer, and wherein the physical layer comprises a plurality of physical layer devices, the method comprising:

checking the status of said physical layer of said communication link; and

if said checking results in a changed status, said method further comprises;

triggering an interrupt service routine;

determining which physical layer device triggered said interrupt service routine;

calling an appropriate physical layer device interrupt service routine;

determining whether a link verification procedure is needed for said physical layer device; and

initiating a link verification procedure for said changed status if said link verification procedure is needed.

9. The method of claim 8, wherein if said changed status for said physical layer is from UP to DOWN, said link verification procedure comprises:

setting a link verification status to down;

checking the status of said receiver/transmitter layer;

if the status of said receiver/transmitter layer is UP;

checking the current state of said physical layer; and

if said current state of said physical layer is LP

checking the number of fluctuations in the state of said physical layer;

if said number of fluctuations in the state of said physical layer is less than a specified tolerable amount;

enabling network signaling over said communication link.

10. The method of claim 9, wherein if the status of said receiver/transmitter layer is down, said method further comprises disabling network signaling over said communication link.

11. The method of claim 8, wherein if said current state of said physical layer is DOWN, said link verification procedure further comprises:

checking the number of times said task has been performed;

if said number of times is less than a specified number allowed;

returning to said setting a link verification status to down;

else if said number of times is more than a specified number allowed;

stopping said task.

12. The method of claim 9, wherein if said current state of said physical layer is UP, said link verification procedure further comprises:

checking the number of fluctuations in the state of said physical layer; and

if said number of fluctuations in the state of said physical layer is more than a specified tolerable amount;

rescheduling said link verification task.

15. The method of claim 14, wherein when said second level reports a failure, said method further comprises allowing at least one handshake attempt for said transceiver layer before disabling signaling over said communication link.

17. The system of claim 16, wherein said means for monitoring said communication link at said first level comprises an interrupt service routine.

18. The system of claim 16, wherein said means for monitoring said communication link at said second level comprises a communication link maintenance protocol.

19. The system of claim 16, wherein said link verification task comprises a plurality of steps including verifying the status of said transceiver layer, and verifying the stability of said physical layer.

13. A node for use in a wireless optical communication network, said node comprising:

a plurality of node heads, wherein each node head comprises an optical receiver and an optical transmitter;

a control processor coupled to said plurality of node heads, having a link verification module for verifying the status of a communication link between nodes in said network;

a data transport mechanism switch coupled to said plurality of node heads.

14. A method of verifying a communication link in a wireless communication network, wherein the network has a plurality of nodes with transceivers, said method comprising:

monitoring said communication link at a first level, said first level comprising a physical layer of components;

monitoring said communication link at a second level, said second level comprising a transceiver layer;

when said first level reports a change in status;

performing a link verification task;

when said second level reports a failure;

disabling signaling over said communication link; and

when said second level reports a link up request;

verifying a positive status of said physical layer; and

enabling signaling over said communication link.

16. A system for verifying a communication link in a wireless optical communication network, wherein the network has a plurality of nodes with optical transceivers, comprising:

means for monitoring said communication link at a first level, said first level comprising a physical layer of components;

means for monitoring said communication link at a second level, said second level comprising a transceiver layer;

when said first level reports a change in status;

means for performing a link verification task;

when said second level reports a failure;

means for disabling signaling over said communication link; and

when said second level reports a link up request;

means for verifying a positive status of said physical layer; and

means for enabling signaling over said communication link.