Probing method for a multi-station network

• US 20050135270A1
• Filed: 06/24/2004
• Published: 06/23/2005
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Iwics Incorporated
• Original Assignee: Iwics Incorporated
• Inventors: Larsen, James David, Rodman, Paul Jonathan
• Granted Patent: US 7,590,068 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/26 Route discovery packet
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

The invention relates to a method of operating a communication network, the network comprising a plurality of stations which are able to transmit data to and receive data from one another. The method comprises defining a first probing channel for the transmission of probe signals to other stations. Other stations which receive the first probe signals from a probing station indicate to the probing station their availability as destination or intermediate stations. A neighbor table comprising details of these other available stations is maintained at each station. Also, second probe signals are sent and received from stations in the neighbor table and a gradient table comprising data related to the cost of communicating with each neighbor station is maintained at each station, thereby to allow each station to select a predetermined number of intermediate stations for onward transmission of data from an originating station to a destination station at minimum cost.

Claims

1. A method of operating a communication network comprising a plurality of stations each able to transmit and receive data so that the network can transmit data from an originating station to a destination station via at least one opportunistically selected intermediate station, the method comprising:

a) defining at least one probing channel, distinct from at least one data channel;

b) selecting, at each station and according to first predetermined criteria, a probing channel for the transmission of probe signals to other stations;

c) transmitting first probe signals from each station on the selected probing channel, other stations which receive the first probe signals from a probing station responding directly or indirectly to thereby indicate to the probing station their availability as destination or intermediate stations;

d) maintaining, at each station, a neighbor table comprising details of other available stations identified by step (c);

e) transmitting, from a station needing to send data to a destination station that is not a neighbor station, second probe signals to, and receiving second probe signals from, stations in the neighbor table; and

f) maintaining as needed, at each station, a gradient table comprising data related to the cost of communicating with each destination station that is not a neighbor station,

thereby to allow each station to select a predetermined number of intermediate stations for onward transmission of data from an originating station to a destination station at minimum cost.

2. A method according to claim 1 wherein the details of other available stations identified by step (c) include the path loss and power required to reach the other available stations.

3. A method according to claim 1 wherein the second probe signals are transmitted from each station only while the neighbor table of said station contains entries.

4. A method according to claim 1 wherein the method further includes calculating, for each station in the neighbor table, a cost to destination value for the cost of transmitting a message from an originating station to a destination station via each such station in the neighbor table.

5. A method according to claim 4 wherein each station also maintains a temporary record of its own cost to destination value.

6. A method according to claim 4 or claim 5 wherein the cost to destination value is the cumulative cost, via each such station in the neighbor table and any intermediate stations, of transmitting a message from the originating station to the destination station.

7. A method according to claim 4 wherein the method includes the step of maintaining a calculated cost to destination value for each station constant for a period during which other stations can update their own cost to destination values, to prevent stations using obsolete cost to destination values of other stations in their own calculations.

8. A communication network comprising a plurality of client stations each able to transmit and receive data so that the network can transmit a message comprising a plurality of data packets from an originating client station to a destination client station via at least one opportunistically selected intermediate client station, and wherein the network further comprises

a plurality of gateways arranged to serve as access points to the network for client stations;

a plurality of seed stations with which client stations can communicate, each seed station being in communication with at least one gateway, the plurality of seed stations extending the effective connectivity range of the client stations;

and at least one subscriber network manager for monitoring the client stations;

wherein each client station is adapted to;

a) define at least one probing channel, distinct from at least one data channel;

b) select, at each client station and according to first predetermined criteria, a probing channel for the transmission of probe signals to other client stations;

c) transmit first probe signals from each client station on the selected probing channel, other client stations which receive the first probe signals from a probing client station responding directly or indirectly to thereby indicate to the probing client station their availability as destination or intermediate client stations;

d) maintain, at each client station, a neighbor table comprising details of other available client stations identified by step (c);

e) transmit, from a client station needing to send data to a destination client station that is not a neighbor client station, second probe signals to, and receiving second probe signals from, client stations in the neighbor table; and

f) maintain, at each client station, a gradient table comprising data related to the cost of communicating with each neighbor client station,

thereby to allow each client station to select a predetermined number of intermediate client stations for onward transmission of data from an originating client station to a destination client station at minimum cost.