# US 2014/0153514 A1 · Method and device for optimizing access to a medium in a communication network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153514 A1 - Document ID: US20140153514A1 - Status: Published application - Kind: A1 - Application number: 14/118,735 - Filed: 2012-05-14 - Published: 2014-06-05 - Earliest claimed: 2011-05-20 - Assignees: Canon Kabushiki Kaisha - Inventors: Patrice Nezou; Julien Sevin; Pascal Viger - Web page: https://patentgrep.com/patent/US20140153514A1 ## CPC - H04W 74/0816: with collision avoidance - H04L 12/413: with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD] - H04W 74/085: {collision avoidance} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The invention is directed to the optimization of an access to a medium in wireless networks which can be accessed by a plurality of nodes, each node of the plurality of nodes using a medium access mechanism of the Carrier Sense Multiple Access with Collision Avoidance type based on a computation of a backoff value. A specific value is associated with each node of a set of nodes of the plurality of nodes, the specific value of a node being known by the other nodes of the set of nodes. According to the invention, a backoff value is determined (505, 510) for each node of the set of nodes, in each node of the set of nodes, the backoff value associated with a node being determined as a function of the specific value associated with that node. ## Claims ### Claim 1 A method for optimizing access to a medium in a communication network which can be accessed by a plurality of nodes, each node of the plurality of nodes using a medium access mechanism of the Carrier Sense Multiple Access with Collision Avoidance type based on a computation of a backoff value, the method being characterized in that a specific value is associated with each node of a set of nodes of the plurality of nodes, the specific value of a node being known by the other nodes of the set of nodes, and in that a step of determining a backoff value for each node of the set of nodes is carried out in each node of the set of nodes, the backoff value associated with a node being determined as a function of the specific value associated with that node. ### Claim 2 (depends on 1) The method according to claim 1 further comprising a step of decrementing the backoff value associated with each node of the set of nodes if all the backoff values associated with the nodes of the set of nodes are different from zero, the step of decrementing the backoff values being carried out in each node of the set of nodes. ### Claim 3 (depends on 1) The method of claim 1 further comprising a step of determining whether or not a collision would occur according to the medium access mechanism if the backoff value associated with a node of the set of nodes reaches zero, the step of determining if a collision would occur being carried out in each node of the set of nodes. ### Claim 4 (depends on 3) The method according to claim 3 further comprising, if a collision would occur, a step of increasing the value of a contention window used for determining the backoff value for each node of the set of nodes, the step of increasing the value of the contention window being carried out in each node of the set of nodes, the step of determining a backoff value being carried out again in each node of the set of nodes, for the node of the set of nodes at the origin of the collision, after the value of the contention window is increased. ### Claim 5 (depends on 3) The method according to claim 3 further comprising the following steps if no collision would occur, transmitting data through the communication network, the step of transmitting data being carried out by the node of the set of nodes whose associated backoff value is equal to zero; and determining a new backoff value for the node of the set of nodes whose associated backoff value is equal to zero, the step of determining a new backoff value for the node of the set of nodes whose associated backoff value is equal to zero being carried out in each node of the set of nodes. ### Claim 6 (depends on 1) The method according to claim 1 wherein the function applied on the specific value associated to each node of the set of nodes is a pseudo-random generator taking the associated specific value as a seed. ### Claim 7 (depends on 6) The method according to claim 6 wherein the pseudo-random generators used in each node of the set of nodes are based on a same random value computation algorithm. ### Claim 8 (depends on 1) The method according to any one of claim 1 further comprising a step of verifying that the backoff value determined for a node of the set of nodes is different from the backoff value determined for each other node of the set of nodes, another backoff value being determined if a backoff value determined for a node of the set of nodes is equal to the backoff value determined for another node of the set of nodes, the verifying step being carried out in each node of the set of nodes. ### Claim 9 (depends on 1) The method according to claim 1 wherein the step of determining a backoff value for each node of the set of nodes is carried out again in each node of the set of nodes upon reception of a specific message generated when a new node is added to the set of nodes. ### Claim 10 (depends on 1) The method according claim 1 wherein the specific values associated with the nodes of the set of nodes are node identifiers. ### Claim 11 (canceled) ### Claim 12 (depends on 1) An information storage means readable by a computer or a microprocessor storing instructions of a computer program, characterized to implement a method of optimizing access to a medium according to claim 1. ### Claim 13 A device for a node for optimizing access to a medium in a communication network that can be accessed by a plurality of nodes, each node of the plurality of nodes using a medium access mechanism of the Carrier Sense Multiple Access with Collision Avoidance type based on a computation of a backoff value, the device being characterized in that a specific value is associated with each node of a set of nodes of the plurality of nodes, the specific value of a node being known by the other nodes of the set of nodes, and in that the device comprises means for determining a backoff value for each node of the set of nodes, the backoff value associated with a node being determined as a function of the specific value associated with that node. ### Claim 14 (depends on 13) The device of claim 13 further comprising means for decrementing the backoff value associated with each node of the set of nodes if all the backoff values associated with the nodes of the set of nodes are different from zero. ### Claim 15 (depends on 13) The device of claim 13 further comprising means for determining whether or not a collision would occur according to the medium access mechanism if the backoff value associated with a node of the set of nodes reaches zero. ### Claim 16 (depends on 15) The device of claim 15 further comprising means for increasing the value of a contention window used for determining the backoff value for each node of the set of nodes, if a collision would occur, the means for determining a backoff value being invoked by the means for increasing the value of the contention window, for determining a backoff value for the node of the set of nodes at the origin of the collision. ### Claim 17 (depends on 13) The device according to claim 13 further comprising means for verifying that the backoff value determined for a node of the set of nodes is different from the backoff value determined for each other node of the set of nodes and for determining another backoff value if a backoff value determined for a node of the set of nodes is equal to the backoff value determined for another node of the set of nodes. ### Claim 18 (canceled)