Methods and systems for providing multiple access within a network

• US 9,491,796 B2
• Filed: 01/22/2013
• Issued: 11/08/2016
• Est. Priority Date: 06/03/2008
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Bange, Joseph E., Koshiol, Allan T., Holmquist, Paul, Kramer, Karen M., Harris, Thomas J.
• Primary Examiner(s): Foud, Hicham
• Application Number:
  US13/746,568
• Publication Number:
  US 20130136035A1
• Time in Patent Office: 1,386 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

Methods and systems for media access control allow master and slave nodes of a network to communicate using the same carrier while avoiding collisions of transmissions. At least one slave node is an implantable device. Master nodes initiate all data exchange sequences, and slave nodes are responsive to the data exchange sequences. The exchange sequences begin by master nodes contending for use of the carrier through a countdown procedure. A set order of communications occurs between a master node who won the contention and a slave node being communicated with by the master node to transfer a data frame. Contention is then repeated to determine the next master node that is allowed to transfer a data frame. New master nodes entering the network employ a discovery process to poll for existing devices in the network.

Claims

1. A method of communicating between a first master node and a first slave node, wherein contention for a carrier of a network medium occurs between a plurality of master nodes, comprising:

determining at the first master node, whether to send or receive data;

at the first master node, gaining use of the carrier; and

sending, from the first master node, a request to send message when the first master node determines to send data to the first slave node, and a request for request to send message when the first master node determines to receive data from the first slave node,

wherein the request for request to send message requests another node to send data, and

wherein a sent message includes an access code;

at the first slave node, receiving the request for request to send message having an access code, and determining whether the access code of the request for request to send message corresponds to the first slave node;

after determining that the access code of the request for request to send message does correspond to the first slave node, sending a request to send message from the first slave node;

at the first master node, upon receiving the request to send message, sending a clear to send message from the first master node;

at the first slave node, upon receiving the clear to send message, sending a data send message from the first slave node, wherein the data send message contains data for use by the first master node;

at the first master node, after receiving the data send message, sending an acknowledge message; and

at the first slave node, receiving the acknowledge message;

wherein the first slave node is an implantable device.

2. The method of claim 1, further comprising:

after receiving the clear to send message, detecting at the first slave node whether multiple frames of data are to be sent; and

when multiple frames of data are to be sent, then sending a data send message that indicates that additional frames of data are to be sent.

3. The method of claim 1, further comprising discarding at the first slave node data sent in the data send message after receiving the acknowledge message.

4. The method of claim 3, further comprising saving at the first slave node data sent in the data send message for transmission in response to receiving a next request for request to send message if the acknowledge message is not received within a timeout.

5. A method of communicating between a first master node and a first slave node, wherein the first slave node is an implantable device, and wherein contention for a carrier of a network medium occurs between a plurality of master nodes, the method comprising:

determining at the first master node, whether to send or receive data;

at the first master node, gaining use of the carrier; and

broadcasting, from the first master node, a request to send message with a universal access code when the first master node determines to send data, or a request for request to send message when the first master node determines to receive data, wherein the request for request to send message requests another node to send data;

detecting, by a second master node, whether a clear to send message with the universal access code is received; and

contending for the carrier by the second master node when the clear to send message is undetected by the second master node upon expiration of a timeout interval and upon expiration of a first contention interval that follows the timeout interval.

6. The method of claim 5, including:

detecting, by the second master node and upon the second master node detecting the clear to send message before expiration of the timeout interval, whether a data send message with the universal access code is received; and

contending for the carrier by the second master node when the data send message is undetected by the second master node and upon expiration of a second contention interval.

7. The method of claim 6, including:

determining, by the second master node and upon detecting the data send message, whether an identifier of the second master node is included in a data field of the data send message;

replying, by the second master node, to discovery messages from the first master node when the identifier is excluded from the data field; and

ignoring discovery messages from the first master node when the identifier is included from the data field.

8. The method of claim 6, including:

detecting, by the second master node and upon the second master node detecting the data send message, an acknowledge message with the universal access code; and

contending for the carrier by the second master node.

9. A method of communicating between a first master node and a

first slave node, wherein contention for a carrier of a network medium occurs between a plurality of master nodes, comprising:

determining at the first master node, whether to send or receive data;

at the first master node, gaining use of the carrier; and

sending, from the first master node, a request to send message when the first master node determines to send data to the first slave node, and a request for request to send message when the first master node determines to receive data from the first slave node,

wherein the request for request to send message requests another node to send data, and

wherein a sent message includes an access code;

detecting at a first slave node that the request to send message contains the access code of the first slave node;

in response to detecting the access code at the first slave node, sending a clear to send message from the first slave node;

receiving the clear to send message at the first master node;

in response to receiving the clear to send message, sending a data send message from the first master node, wherein the data send message specifies a disconnect command;

receiving the data send message at the first slave node;

in response to receiving the data send message, sending an acknowledge message from the first slave node and discarding the access code at the first slave node;

receiving the acknowledge message at the first master node; and

in response to receiving the acknowledge message at the first master node, identifying at the first master node the access code as no longer being in use;

wherein the first slave node is an implantable device.