CONTENTION BASED MEDIA ACCESS MECHANISM

• US 20090022174A1
• Filed: 06/24/2008
• Published: 01/22/2009
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Wang, Zhaocheng, Wang, Qi
• Granted Patent: US 7,990,997 B2
• Time in Patent Office: Days
• US Class Current: 370/462
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

The present invention relates to the field of contention in a network of communicating nodes. The present invention especially relates to a master node for a communication network, to a slave node device for a communication network, to a network comprising the master node device and at least one slave node device and to a method of contention in a network of nodes. The method of contention according to the present invention is method in a network comprising slave nodes, said slave nodes comprising a group of first slave nodes, the method comprising the step of sending, by every first slave node participating in a contention, a number of two or more contention participation messages during a contention window associated with the first slave node.

Claims

1. A master node device (1) for a communication network (3) comprising slave nodes (2), said slave nodes comprising a group of first slave nodes (2), said master node device (1) comprising

a communication unit (4-1) operable to

receive two or more contention participation messages (9) sent from one first slave node (2) during a contention window (12) associated with that first slave node (2),

select one of the received two or more contention participation messages (9) for further processing and neglect the others.

2. A master node device (1) according to claim 1 wherein

the communication unit (4-1) is adapted to

determine a number of contention participation messages (9) which are to be sent by each first slave node (2) and

send the determined number of contention participation messages (9).

3. A master node device (1) according to claim 2 wherein

the communication unit (4-1) comprises a radiation or wave emitter and receiver (7-1), whereby

said group of first slave nodes comprises only slave nodes (2-1, 2-2) with which the master node device (1) is able to communicate based on a common direction of emission and reception of the radiation or wave emitter and receiver (7-1).

4. A master node device (1) according to claim 2 wherein

the determined number of contention participation messages (9) is dependent on the number of first slave nodes (2) which are allowed to send a contention participation message (9).

5. A master node device (1) according to claim 2 wherein

the determined number of contention participation messages (9) is dependent on the number of first slave nodes (2) which are expected to send a contention participation message (9).

6. A master node device (1) according to claim 2 wherein

the communication unit (4-1) is adapted to

repeatedly determine the number of contention participation messages (9) and send it to the first slave nodes (2).

7. A master node device (1) according to claim 1 wherein

the communication unit (4-1) is adapted to

repeatedly send a beacon signal (10) and receive contention participation messages (9) during a beacon period (10) and a following contention period (12), respectively.

8. A master node device (1) according to claim 7 wherein

said beacon period (10) and said following contention period (12) together form a path scanning period,

whereby

the beacon signal (10) and the contention participation messages (9) of a given path scanning period are sent and received using a same direction of emission and reception and

the beacons (10) and contention participation messages (9) of at least two different path scanning periods are sent and received using different directions of emission and reception.

16. A communication network (3) comprising a master node device (1) according to claim 1 and at least one slave node device (2) according to claim 9.

9. A slave node device (2) for a communication network (3) comprising slave nodes (2), said slave nodes (2) comprising a group of first slave nodes (2), said slave node device (2) being a member of said group of first slave nodes (2),

said slave node device (2) comprising

a communication unit (4-2) adapted to send two or more contention participation messages (9) during a contention window (12) associated with the slave node device (2).

10. A slave node device (2) according to claim 9 comprising

a control unit (6-2) adapted to

determine a number of contention participation messages (9) which are to be sent during the contention window (12).

11. A slave node device (2) according to claim 10 wherein

the number of contention participation messages (9) is indicated in a signal received by the slave node device (2) and

the control unit (6-2) is adapted to

determine the number of contention participation messages (9) based on the received signal.

12. A slave node device (2) according to claim 10 wherein

the control unit (6-2) is adapted to

repeatedly determine the number of contention participation messages (9).

13. A slave node device (2) according to claim 9 wherein

the communication unit (4-2) is adapted to

repeatedly receive a beacon signal (10) and send contention participation messages (9) during a beacon period (10) and a following contention period (12), respectively.

14. A slave node device (2) according to claim 13 wherein

said beacon period (10) and said following contention period (12) together form a path scanning period,

whereby

the beacon signal (10) and the contention participation messages (9) of a given path scanning period are received and sent using a same direction of emission and reception and

the beacons signals (10) and contention participation messages (9) of at least two different path scanning periods are received and sent using different directions of emission and reception.

15. A slave node device (2) according to claim 13 wherein

the control unit (6-2) is adapted to

determine if the communication unit (4-2) has successively received a beacon signal (10) in a given beacon period (10) and

determine a set of communication channels (18), each communication channel (18) adopted to transmit exactly one contention participation message (9), said set of communication channels (18) corresponding to said contention window (12),

whereby

said set of communication channels (18) is determined to comprise communication channels (18) from among communication channels (18) provided by the contention period (10) following a given beacon period (10) in case that a beacon signal (10) is determined to be successively received in the given beacon period (10)

and

said set of communication channels (18) is determined not to comprise communication channels (18) from among communication channels (18) provided by the contention period (12) following a given beacon period (10) in case that a beacon signal (10) is not determined to be successively received in the given beacon period (10).

17. A method of contention in a network (3) comprising slave nodes (2), said slave nodes (2) comprising a group of first slave nodes (2), the method comprising the step of

sending (S18), by every first slave node (2) participating in a contention, a number of two or more contention participation messages (9) during a contention window (12) associated with the first slave node (2).

18. A method according to claim 17 comprising the step of

automatically determining (S20) a number of contention participation messages (9) which are to be sent by each first slave node,

whereby,

in case the determined number is equal or more than two, the step of sending (S18), by every first slave node (2) participating in the contention, a number of two or more contention participation messages (9) is executed and the number of two or more contention participation messages (9) is given by the determined number and,

in case that the determined number of contention participation messages (9) is one, instead of executing the step of sending (S18), by every first slave node (2) participating in the contention, a number of two or more contention participation messages (9), a step of sending (S18), by every first slave node (2) participating in the contention, one contention participation message (9) during the contention window (12) associated with the first slave node (2) is executed.

19. A method according to claim 18 wherein the network (3) comprises a master node (1), said master node (1) comprising a radiation or wave emitter and receiver (7-1), whereby

said first group of first slave nodes comprises only slave nodes (2-1, 2-2) with which the master node (1) is able to communicate based on a common direction of emission and reception of the radiation or wave emitter and receiver (7-1).

20. A method according to claim 18 wherein the step of

automatically determining (S20) a number of contention participation messages (9) is based on the number of first slave nodes (2) which are allowed to participate in the contention.

21. A method according to claim 18 wherein the step of

automatically determining (S20) a number of contention participation messages (9) is based on the number of first slave nodes which are expected to participate in the contention.

22. A method according to claim 18 wherein the step of

automatically determining (S20) a number of contention participation messages (9) is executed repeatedly.

23. A method according to claim 17 comprising the step of

repeatedly sending a beacon signal (10) from a master node (1) to the slave nodes (2) and contention participation messages (9) from the slave nodes (2) to the master node (1) during a beacon period (10) and a following contention period (12), respectively.

24. A method according to claim 23 wherein

said beacon period (10) and said following contention period (12) together form a path scanning period,

whereby

contention participation messages (9) of a given path scanning period and sent by a given slave node (2) and the beacon signal (10) of said given path scanning period are transmitted using a same communication path and

contention participation messages (9) of at least two different path scanning periods and sent by a given slave node (2) and the beacon signals (10) of said at least two different path scanning periods are transmitted using different communication paths.

25. A method according to claim 23 comprising the steps of

determining, for every first slave node (2), if the first slave node (2) has successively received a beacon signal (10) in a given beacon period (10) and

determining, for every first slave node (2), a set communication channels (18), each communication channel (18) adapted to transmit exactly one contention participation message, said set of communication channels corresponding to said contention window (12) associated with the first slave node (2),

whereby,

in case that a beacon signal (10) is determined to be successively received in a given beacon period (10) by one of the first slave nodes (2), the set of communication channels (18) is determined to comprise communication channels (18) from among communication channels (18) provided by the contention period (10) following the given beacon period (10)

and,

in case that a beacon signal (10) is not determined to be successively received in a given beacon period, said set of communication channels (18) is determined not to comprise communication channels (18) from among communication channels (18) provided by the contention period (12) following a given beacon period (10).