Method for data transmission in a local area network

• US 8,797,885 B2
• Filed: 10/28/2009
• Issued: 08/05/2014
• Est. Priority Date: 11/07/2008
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Bahr, Michael, Vicari, Norbert
• Primary Examiner(s): Phung, Luat
• Application Number:
  US13/128,167
• Publication Number:
  US 20110211461A1
• Time in Patent Office: 1,742 Days
• Field of Search: 370/245
• US Class Current: 370/245
• CPC Class Codes: G05B 2219/31162 Wireless lan
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04W 74/0891 for synchronized access

Abstract

A method for data transmission in a local are network, wherein data is transmitted on the Media Access Control (MAC) layer within successive time frames between a plurality of first nodes comprising client nodes to a second node comprising a coordinator node for the plurality of first nodes. A synchronizing slot for sending a synchronizing message from the second node to the first nodes includes acknowledgements for time slots used for data transmissions in previous time frames from the first nodes to the second node. The acknowledgements indicate whether a data transmission in the previous time frame was successful. Based on these acknowledgements, retransmission time slots included in the current time frame are used for retransmitting data that have not been transmitted successfully in a time slot of the previous time frame.

Claims

1. A method for transmitting data on a Media Access Control layer in a local area network within successive time frames between a plurality of first nodes comprising client nodes and a second node comprising a coordinator node for the plurality of first nodes, wherein each of the time frames includes a synchronization slot and a plurality of time slots including first slots and second slots, the method comprising:

sending, in the synchronization slot of a current time frame of the successive time frames, a synchronizing message from the second node to the first nodes to synchronize the data transmission between the first nodes and the second node; and

sending data from the first nodes to the second node, each of the first nodes using the first slots for an initial transmission of data from each of the first nodes to the second node;

wherein the synchronizing slot of the current frame includes first acknowledgements associated with the first slots of a previous time frame preceding the current time frame, a positive first acknowledgement for a particular first slot indicating that a data transmission in the particular first slot was successful and a negative first acknowledgement indicating that the data transmission was unsuccessful, and

wherein each of the first nodes uses the second slots for retransmission of data previously transmitted in one of the first slots of the previous time frame if each of the first nodes receives a negative first acknowledgement for the one of the first slots of the previous time frame in the synchronizing slot; and

wherein the first slots are arranged in a sequence of successive first slots and the second slots are arranged in a sequence of successive second slots in the successive time frames, the sequence of second slots being arranged before the sequence of first slots.

2. The method according to claim 1, wherein the data is transmitted in a wireless personal area network comprising a wireless sensor network, each of the first nodes representing a sensor transmitting sensor data to the second node representing a base station in a sensor network.

3. The method according to claim 2, wherein the data in the wireless personal area network is transmitted in accordance with IEEE standard 802.15.4.

4. The method according to claim 2, wherein the data in the wireless personal area network is transmitted in accordance with IEEE standard 802.15.4e.

5. The method according to claim 1, wherein the first acknowledgements are at least one of included in the synchronizing message and sent immediately one of before and after the synchronizing message.

6. The method according to claim 1, wherein the second node assigns the use of the second slots in the current time frame to the ones of the first nodes for which the data transmission in a first slot of the previous time frame was unsuccessful.

7. The method according to claim 1, wherein successive slot numbers are assigned to the first slots chronologically in an order of an occurrence of the first slots in the current time frame, each slot number assigning the first slot to a predetermined first node using the first slot for data transmission.

8. The method according to claim 1, wherein successive slot numbers are assigned to the second slots chronologically in an order of an occurrence of the second slots, in the current time frame.

9. The method according to claim 7, wherein one of the first node of the plurality of node intending to retransmit data due to a negative first acknowledgement for one of the first slots with a given slot number determines a slot number of the second slot to be used for retransmission by the following steps:

i) scanning the first acknowledgements in the synchronizing slot to determine a number of unsuccessful data transmissions in the first slots having slot numbers smaller than a given slot number; and

ii) determining a slot number of the second slot to be used for the retransmission as the number of the unsuccessful transmissions plus one.

10. The method according to claim 8, wherein one of the first nodes intending to retransmit data due to a negative first acknowledgement for one of the first slots with a given slot number determines a slot number of the second slot to be used for retransmission by:

i) scanning the first acknowledgements in the synchronizing slot to determine a number of unsuccessful data transmissions in the first slots having slot numbers smaller than a given slot number; and

ii) determining a slot number of the second slot to be used for the retransmission as the number of the unsuccessful transmissions plus one.

11. The method according to claim 10, wherein the second node transmitting the first acknowledgements in the synchronizing slot determines, for one of the first slots with a given slot number and associated with a negative first acknowledgement, the slot number of the second slot used for retransmitting the data previously transmitted in the one of the first slots by:

a) scanning the first acknowledgements in the synchronizing slot to determine the number of unsuccessful data transmissions in first slots having slot numbers smaller than the given slot number;

b) determining the slot number of the second slot used for retransmission as the number of the unsuccessful transmissions plus one.

12. The method according to claim 10, wherein the one of the first nodes does not retransmit data due to a negative first acknowledgement for the one of the first slots with a given slot number when the number of unsuccessful data transmissions determined in step i) is not smaller than the total number of second slots in the current time frame.

13. The method according to claim 11, wherein the one of the first nodes does not retransmit data due to a negative first acknowledgement for the one of the first slots with a given slot number when the number of unsuccessful data transmissions determined in step i) is not smaller than the total number of second slots in the current time frame.

14. The method according to claim 7, wherein the successive slot numbers are assigned to all time slots chronologically in an order of the occurrence of the time slots.

15. The method according to claim 1, wherein at least some of the first slots are concatenated to at least one group of the first slots, the data transmitted in at least one group of the first slots being retransmitted if any data transmission the at least one group of the first slots is unsuccessful.

16. The method according to claim 1, wherein the synchronizing slot of the current time frame includes second acknowledgements associated with the second slots, of a previous time frame preceding the current time frame, a positive second acknowledgement for a particular second slot of the second slots indicating that the data transmission in the particular second slot was successful and a negative second acknowledgement indicating that the data transmission in the particular second slot was unsuccessful.

17. The method according to claim 16, wherein the second slots are used by each of the first nodes for retransmitting data transmitted by each of the first nodes in a second slot of a previous time frame if each of the first nodes receives a negative second acknowledgement for the second slot in the synchronizing slot.

18. A local area network, comprising:

a plurality of first nodes comprising client nodes; and

a second node comprising a coordinator node for the first nodes;

wherein the network is configured for data transmission on a Media Access Control layer within successive time frames between the plurality of first nodes and the second node;

wherein a current time frame of the successive time frames comprises a synchronizing slot for sending a synchronizing message from the second node to the plurality of first nodes to synchronize the data transmission between the plurality of first nodes and the second nodes , a plurality of time slots including first slots and second slots, the first slots being used for an initial transmission of data from the first nodes of the plurality of nodes to the second node;

wherein the synchronizing slot of the current frame includes first acknowledgements associated with the first slots of the slots of a previous time frame preceding the current time frame, a positive first acknowledgement for a particular first slot of the first slots indicating a data transmission in the particular first slot was successful and a negative first acknowledgement indicating that the data transmission was unsuccessful, and the second slots being used by each of the first nodes for retransmission of data previously transmitted in one of the first slots of the previous time frame if each of the first nodes receives a negative first acknowledgement for the one of the first slots of the previous time frame in the synchronizing slot; and

wherein the first slots are arranged in a sequence of successive first slots and the second slots are arranged in a sequence of successive second slots in the successive time frames, the sequence of second slots being arranged before the sequence of first slots.

19. The local area network according to claim 18, wherein the local area network is configured to transmit the data in a wireless personal area network comprising a wireless sensor network, each of the first nodes representing a sensor transmitting sensor data to the second node representing a base station in a sensor network.

20. The local area network according to claim 19, wherein the data in the wireless personal area network is transmitted in accordance with IEEE standard 802.15.4.

21. The local area network according to claim 19, wherein the data in the wireless personal area network is transmitted in accordance with IEEE standard 802.15.4e.