Link layered networks

• US 20060067282A1
• Filed: 09/24/2004
• Published: 03/30/2006
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: AES Corporation
• Original Assignee: AES Corporation
• Inventors: Sherman, Michael, Bastable, James P. Jr.
• Granted Patent: US 8,072,945 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 28/0289 Congestion control load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 40/04 based on wireless node resources
• CPC Class Codes: H04W 8/245 from a network towards a terminal
• 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

A method and system for optimizing and keeping operational a wireless link layered network in which a system control and modifying message (SCMM) is elicited from nodes receiving information packets and based upon whether the node originating the SCMM is from a link layer level is equal to or less than the link layer level eliciting the SCMM, rerouting or adjusting future transmissions can be effected or items like a current time at a receiving node and a most recent utilization rate of a receiving node can be adjusted, recorded or set.

Claims

1. A method of dynamically keeping operational and optimized, without operator intervention, in response to changes occurring at any node, a wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, said method comprising the steps of:

(a) from each node successfully receiving an information packet, eliciting as an acknowledgment, a system control and modifying message (SCMM) containing optionally the following items of information;

(a₁) a current time at the receiving node,

(a₂) a received signal strength,

(a₃) a packet length or capacity of the receiving node,

(a₄) a most recent utilization rate of the receiving node,

(a₅) a deviation from standard network frequency of the received information packet,

(a₆) an identification of the receiving node,

(a₇) an identification of the node eliciting the SCMM, and

(a₈) a packet sequence identifier for the acknowledged information packet;

(b) determining whether the node originating the SCMM is from a link layer level equal to or less than the link layer level of the node eliciting the SCMM; and

(c) where the node originating the SCMM has a link layer level equal to or less than the link layer level of the node eliciting the SCMM, at the eliciting node and in response to the SCMM, rerouting and/or adjusting future transmissions based at least upon some of the information items (a₁-a₆) contained in the SCMM.

2. The method defined in claim 1, further comprising:

at the node eliciting the SCMM;

(i) determining whether the node receiving the acknowledged information packet and from which the SCMM has been elicited has adequate capacity for the acknowledged information packet;

(ii) if the node from which the SCMM has been elicited has insufficient capacity, registering that capacity for other messages and routing future messages requiring the capacity of the acknowledged information packet through other nodes; and

(iii) if the node from which the SCMM has been elicited has sufficient capacity, registering that capacity and continue to route future messages requiring the capacity of the acknowledged information packet through that node.

3. The method defined in claim 1, further comprising:

at the node eliciting said SCMM;

(i) determining whether the node from which the SCMM has been elicited has adequate received signal strength for the acknowledged information packet;

(ii) if the node from which the SCMM has been elicited has insufficient received signal strength, at the eliciting node, increasing power by an amount which will cause the received signal strength to be equal to an ideal signal strength for other messages to be routed through that node;

(iii) if the node from which the SCMM has been elicited has greater received signal strength than an ideal value, decreasing power by an amount which will cause the received signal strength to be equal to the ideal signal strength; and

(iv) registering a new power value for the node from which the SCMM has been elicited.

4. The method defined in claim 3 wherein, in step (ii), the power is increased to a maximum power available at the node eliciting the SCMM.

5. The method defined in claim 1, further comprising:

from the utilization rate included in the SCMM, determining at the node eliciting the SCMM whether the utilization of the node from which the SCMM has been elicited is such that the node from which the SCMM has been elicited should be used further and/or

altering routing information stored at least one of a plurality of nodes receiving the broadcast SCMM based upon the degree of utilization incorporated in the SCMM.

6. The method defined in claim 1, further comprising:

from the utilization rate included in the SCMM, determining at the node eliciting the SCMM whether the utilization of the node from which the SCMM has been elicited is such that the node from which the SCMM has been elicited should be used further and/or

altering routing information stored in the node eliciting the SCMM.

7. The method defined in claim 1, further comprising:

from information in said SCMM as to a deviation from standard network frequency of the received information packet, reducing a broadcast frequency a t the node eliciting the SCMM to equal an SCMM originating node frequency or increasing the broadcast frequency at the node eliciting the SCMM to equal the SCMM originating node frequency.

8. The method defined in claim 7, further comprising the step of storing a new frequency at the node eliciting the SCMM in a frequency database thereof.

9. The method defined in claim 1, further comprising:

comparing said current time information of the SCMM with a clock of a node receiving the SCMM; and

decreasing or increasing the time of the clock at each node receiving said SCMM to equal the time represented by said time information plus the time to propagate the time signal to the respective node.

10. A method of dynamically keeping operational and optimized, without operator intervention, in response to changes occurring at any node, a wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, said method comprising the steps of:

(a) broadcasting from each node successfully receiving an information packet, as an acknowledgment, a system control and modifying message (SCMM) containing at least the following items of information;

(a₁) a current time at the receiving node, and

(a₂) a most recent utilization rate of the receiving node,

(b) at any node capturing said SCMM, determining whether the node originating the SCMM is from a link layer level equal to or less than the link layer level of the node capturing the SCMM; and

(c) where the node originating the SCMM has a link layer level equal to or less than the link layer level of the node capturing the SCMM, in response to the SCMM carrying-out required changes at all nodes of the network capturing said SCMM based upon the information items (a₁ and a₂) contained in the SCMM.

11. The method defined in claim 10 wherein said changes include adjustment of local time at each of the nodes capturing said SCMM based upon the time information (a₁).

12. The method defined in claim 10 wherein said changes include rerouting of information packets to other nodes than said receiving node when said receiving node has a utilization rate above a preset threshold.

13. A method of preventing network oscillation in a wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, said method comprising the steps of:

(a) from each node from which a message is to be sent to other nodes of said network, attaching a token specific to each message sent;

(b) sending the messages with the tokens attached to other nodes of the network; and

(c) rejecting for retransmission at each node any received message containing the token specific to that node.

14. A method of preventing network congestion upon restart of a wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, said method comprising stratifying reestablishment of communication among said nodes whereby restart is effected layer by layer, and within each link layer level, restart time is randomized.

15. A wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, some of the nodes having a link layer level less than the link layer level of others of said nodes, said nodes being configured upon successfully receiving an information packet, to generate as an acknowledgment, a system control and modifying message (SCMM) containing optionally the following items of information:

(a₁) a current time at the receiving node,

(a₂) a received signal strength,

(a₃) a packet length or capacity of the receiving node,

(a₄) a most recent utilization rate of the receiving node,

(a₅) a deviation from standard network frequency of the received information packet,

(a₆) an identification of the receiving node,

(a₇) an identification of the node eliciting the SCMM, and

(a₈) a packet sequence identifier for the acknowledged information packet,

each transmitting node determining whether the node originating the SCMM is from a link layer level equal to or less than the link layer level of the node eliciting the SCMM, and where the node originating the SCMM has a link layer level equal to or less than the link layer level of the node eliciting the SCMM, in response to the SCMM at the node eliciting the SCMM, rerouting and/or adjusting future transmissions based at least upon some of the information items (a₁-a₆) contained in the SCMM.

16. A wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, said nodes being configured upon successful receipt of an information packet, to generate as an acknowledgment, a system control and modifying message (SCMM) containing at least the following items of information:

(a₁) a current time at the receiving node, and

(a₂) a most recent utilization rate of the receiving node, and

upon determining whether the node originating the SCMM is from a link layer level equal to or less than the link layer level of the node eliciting the SCMM, resetting a local time for each node receiving the SCMM where the node originating the SCMM has a link layer level equal to or less than the link layer level of the node eliciting the SCMM, in response to current time of the SCMM or rerouting information packets to other nodes in response to an excessive utilization rate of the node originating the SCMM.

17. A wireless link layered network comprising a plurality of transceivers at respective nodes which route communications from any node to a then central node of the network and wherein said communications are in a form of information packets transmitted from one node to another, in which the continuous retransmission of the same message in a sub set of the nodes is prevented, said prevention being effected by including in each information packet to be sent to other nodes of said network a token specific to the sending node and by rejecting for retransmission at each node any received message containing the token specific to that node.

21. The wireless link layered network defined in claim 17 for a submetering system for at least one building formed with a main mode which can communicate with a central node adapted to communicate with a plurality of main nodes, and a plurality of secondary nodes in said building each servicing a respective meter.

18. A wireless link layered network, which in response to changes at any node, is dynamically and without the intervention of an operator kept operational, by promulgating into the network information as to such changes via message acknowledging SCMM, and assuring that only the node eliciting such an SCMM uniquely acts upon said information, providing the SCMM originated from a node having a link layer equal or lower than the eliciting node.

19. A wireless link layered network according to claim 18, which in response to communication crowding in some of its communication paths, dynamically and without the intervention of an operator reroutes messages to parts of the network that are less congested, said rerouting being affected by including in the SCMM a measure of the utilization rate of the node originating the SCMM, and if said utilization rate exceeds a preset level, reroute messages around said SCMM originating node.

20. A wireless link layered network which in response to communication crowding in some of its communication path, dynamically and without the intervention of an operator reroutes message to parts of the network that are less congested, said rerouting being affected by having all nodes capturing an SCMM from a node having high utilization rate exceeding a preset level, removing said SCMM originating node from their respective routing list, provided that the link layer level of the node originating the SCMM is equal or lower than each respective node capturing said SCMM.