Wireless network for automation, realtime and/or industrial applications

• US 9,191,881 B2
• Filed: 03/11/2011
• Issued: 11/17/2015
• Est. Priority Date: 03/12/2010
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Benjamins, Kai, Keller, Stefan, Mller, Jrg, Wolf, Stephan, Ober, Martin
• Primary Examiner(s): Lee, Jae Y
• Assistant Examiner(s): OH, ANDREW CHUNG SUK
• Application Number:
  US13/046,499
• Publication Number:
  US 20110222510A1
• Time in Patent Office: 1,712 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/20 between access points
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention describes a wireless network, in particular for automation, realtime and/or industrial applications, having at least two access network nodes and at least one radio station for wireless communication with at least one of the at least two access network nodes, wherein each of the at least two access network nodes uses a data channel selected from a set of available selectable data channels for wireless communication with a radio station assigned to it in each case, wherein a control communication channel which is distinct from the selectable data channels is provided in addition, and each of the at least two access network nodes is embodied for wirelessly sending information messages over the control communication channel and the at least one radio station is embodied for receiving the control communication channel.

Claims

1. A wireless network configured for at least one of automation, real-time and industrial applications, comprising:

a plurality of access network nodes, each of the plurality of access network nodes including a first transmit/receive unit for radio communication over a selected data channel and a second transmit unit for sending heartbeat messages configured as a beacon frame over a control communication channel; and

at least one radio station for wireless communication with at least one of the plurality of access network nodes;

wherein each of the plurality of access network nodes utilizes a data channel selected from a set of available selectable data channels for wireless communication with a radio station of the at least one radio station assigned to the each of the plurality of access network nodes;

wherein the control communication channel is distinct from the selectable data channels, each of the plurality of access network nodes being configured for wirelessly sending the heartbeat messages configured as the beacon frame over the control communication channel, the beacon frame including an information element which identifies a sending access point as an access point having a separate management channel and simultaneously notifies a client of the selected data channel of the access point, and the at least one radio station being configured for receiving the control communication channel; and

wherein the first transmit/receive unit is assigned a first antenna and the second transmit unit is assigned a second antenna, the first and second antennas having identical or similar antenna characteristics.

2. The wireless network as claimed in claim 1, wherein the plurality of access network nodes are connected by a wireless or wired interface for communication between the plurality of access network nodes.

3. An access network node for a wireless network, comprising:

a first transmit/receive unit for radio communication over the selected data channel; and

a second transmit unit for sending the heartbeat messages configured as the beacon frame over a control communication channel;

wherein the first transmit/receive unit is assigned a first antenna and the second transmit unit is assigned a second antenna, the first and second antennas having identical or similar antenna characteristics; and

wherein the access network is configured for radio communication with a radio station in the wireless network over a data channel selected from a set of available data channels and is configured for sending the heartbeat messages configured as the beacon frame over the control communication channel which is distinct from the set of available data channels, the beacon frame including an information element which identifies a sending access point as an access point having a separate management channel and simultaneously notifies a client of the selected data channel of the access point.

4. The access network node as claimed in claim 3, wherein the information messages sent over the control communication channel include identity information relating to an access network node of the plurality of access network nodes.

5. The access network node as claimed in claim 3, wherein the heartbeat messages configured as the beacon frame sent over the control communication channel are transmitted at a predefined or pre-definable transmit intensity.

6. The access network node as claimed in claim 3, wherein the heartbeat messages configured as the beacon frame are transmitted in accordance with a predefined or predefinable time pattern.

7. The access network node as claimed in claim 3, further comprising a communication control unit configured to send communication polling messages to a selection of radio stations assigned to the access network node in the wireless network such that each radio station from the selection of radio stations receives at least one communication polling message within a predefined or predefinable time period.

8. The access network node as claimed in claim 7, wherein the communication polling messages are sent over the selected data channel.

9. The access network node as claimed in claim 7, wherein the control unit is configured such that during a blocking time period assigned to an assigned radio station no communication polling message is sent to the assigned radio station.

10. The access network node as claimed in claim 9, wherein the blocking time period has been or is communicated to the access network node by the radio station.

11. The access network node as claimed in claim 3, further comprising a wireless or wired interface to a further access network node in the wireless network, wherein the access network node and the further access network node are configured such that in a handover of a radio station assigned to the access network nodes to the further access network node as a new assigned access network node of the radio station, at least one of:

data relating to the radio station is transmitted to the further access network node through the wireless or wired interface; and

data relating to the further access network node is transmitted to the radio station.

12. A radio station for a wireless network for communication with an access network node assigned to the radio station, the access node including a first transmit/receive unit for radio communication over a selected data channel and a second transmit unit for sending heartbeat messages configured as a beacon frame over a control communication channel, wherein the radio station is configured for data communication with an access network node assigned to the radio station over a selected data channel and for receiving the heartbeat messages configured as the beacon frame over the control communication channel, the beacon frame including an information element which identifies a sending access point as an access point having a separate management channel and simultaneously notifies a client of the selected data channel of the access point;

and wherein the first transmit/receive unit is assigned a first antenna and the second transmit unit is assigned a second antenna, the first and second antennas having identical or similar antenna characteristics.

13. The radio station as claimed in claim 12, wherein the radio station is configured to send information relating to a blocking time period to the access network node assigned to the radio station, and wherein during the blocking time period the radio station performs or attempts to perform at least a poll of the control communication channel.

14. The radio station as claimed in claim 13, wherein the information relating to the blocking time period is sent over the selected data channel.

15. The radio station as claimed in claim 13, wherein the radio station is configured to send a response data message over the selected data channel to the access network node assigned to the radio station in response to a communication polling message received from the assigned access network node.

16. The radio station as claimed in claim 15, wherein the response data message to the access network node includes the information relating to the blocking time period.

17. The radio station as claimed in claim 12, wherein the radio station is configured to send a response data message over the selected data channel to the access network node assigned to the radio station in response to a communication polling message received from the assigned access network node.

18. The radio station as claimed in claim 17, wherein the response data message to the access network node includes the information relating to the blocking time period.

19. The radio station as claimed in claim 12, wherein the radio station is configured to evaluate the heartbeat messages received over the control communication channel such that the received heartbeat messages are assignable to transmitting access network nodes.

20. The radio station as claimed in claim 12, wherein the radio station includes a device configured to determine a preferred access network node using received heartbeat messages.

21. The radio station as claimed in claim 20, wherein the radio station is configured to initiate a handover to the preferred access network node when the determined preferred access network node does not correspond to a currently assigned access network node and further handover conditions are fulfilled.

22. A method for assigning a radio station to an access network node in a wireless network, wherein the radio station is assigned to a first access network node in the wireless network and a second access network node is included in the wireless network, the first and second access nodes each use a data channel selected from a set of available data channels for wireless communication with an assigned radio station, the method comprising:

a) receiving and evaluating, by the radio station, heartbeat messages configured as a beacon frame of at least one of the first access network node and the second access network node sent over a control communication channel distinct from the set of available data channels, the beacon frame including an information element which identifies a sending access point as an access point having a separate management channel and simultaneously notifies a client of the selected data channel of the access point, the first and second access nodes each including a first transmit/receive unit for radio communication over the selected data channel and a second transmit unit for sending the heartbeat messages configured as the beacon frame over the control communication channel; and

b) determining, by the radio station, a preferred access network node based on at least a result of the evaluation of the heartbeat messages configured as the beacon frame;

wherein the first transmit/receive unit is assigned a first antenna and the second transmit unit is assigned a second antenna, the first and second antennas having identical or similar antenna characteristics.

23. The method as claimed in claim 22, further comprising after method step b):

c1) sending, by the radio station, a heartbeat message relating to a preferred access network node to the at least one of the first access network and the second access network if the second access network node has been identified as the preferred access network node, or

c2) sending, by the radio station, a message for initiating a handover to the second access network node as an assigned network node to the at least one of the first access network node and the second access network node.

24. The method as claimed in claim 22, wherein data relating to the radio station is transmitted from the first to the second access network node for the handover of the radio station from the first to the second access network node as the access network node assigned to the radio station.

25. The method as claimed in claim 24, wherein data relating to the radio station is transmitted from the first to the second access network node for the handover of the radio station from the first to the second access network node as the access network node assigned to the radio station.