Medium Access Control in Industrial and Automotive Wireless with Combined Wired and Wireless Sensor Networks

• US 20090310571A1
• Filed: 06/13/2008
• Published: 12/17/2009
• Est. Priority Date: 06/13/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Dielacher, Markus, Matischek, Rainer, Flatscher, Martin, Prainsack, Josef
• Granted Patent: US 8,787,266 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 84/22 with access to wired networks
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

An embodiment of the invention relates to a local area sensor network including a central unit configured to receive a resource allocation request from a priority network sensor in a reserved timeslot and in response to designate a shared timeslot allocation. The priority network sensor transmits a resource allocation request in a reserved timeslot, and the sensor transmits data in the allocated shared timeslot. A sensor network can be formed with multiple gateways that each communicate over wired and wireless portions of the network. The central unit communicates with the gateways over the wired portion of the network. Wireless nodes communicate wirelessly with the gateways. The central unit receives a plurality of link quality indicators from the gateways for respective wireless paths to the wireless sensors, and selects a gateway for relaying a message from the central unit to a wireless sensor based on the link quality indicators.

Claims

1. A local area network, comprising:

a central unit; and

a priority network sensor unit configured to transmit a resource allocation request in a reserved timeslot, and to receive a reservation bit map including an allocation of a shared timeslot in response to the resource allocation request, and in response thereto to transmit data in the allocated shared timeslot, wherein the central unit is configured to receive the resource allocation request from the priority network sensor unit, and to transmit the reservation bit map including the allocation of the shared timeslot in response to the resource allocation request.

2. The local area network as claimed in claim 1, further including a non-priority network sensor unit, the non-priority network sensor unit configured to receive the reservation bit map, and in response to finding an unallocated shared timeslot therein, transmit data in the unallocated shared timeslot

3. The local area network as claimed in claim 2, wherein the transmitted data in the unallocated shared timeslot is transmitted using a carrier sense multiple access collision avoidance communication mode.

4. The local area network as claimed in claim 1, wherein the central unit is further configured to transmit a beacon to provide synchronization for network sensor units.

5. The local area network as claimed in claim 1, wherein the reservation bit map includes an integrity code.

6. The local area network as claimed in claim 1, wherein the central unit transmits an acknowledgment message in response to receiving data from a network sensor unit.

7. The local area network as claimed in claim 1, wherein the local area network is a wireless sensor network.

8. A sensor network, comprising:

a plurality of gateways configured to communicate over wired and wireless portions of a network;

a wireless node configured to communicate with at least one gateway of the plurality of gateways;

a central unit configured to communicate with the plurality of gateways over the wired portion of the network, the central unit configured to receive a plurality of link quality indicators from the plurality of gateways for respective wireless paths from the wireless node to the plurality of gateways, the central unit further configured to select a gateway of the plurality of gateways for relaying a message from the central unit to the wireless node.

9. The sensor network as claimed in claim 8, wherein the central unit is configured to select the gateway of the plurality of gateways for relaying the message based on the plurality of link quality indicators.

10. The sensor network as claimed in claim 8, wherein the selected gateway relays the message from the central unit using a wireless time division multiple access communication mode.

11. The sensor network as claimed in claim 10, wherein the central unit establishes network synchronization for the wireless time division multiple access communication mode by broadcasting a beacon over the wired portion of the network.

12. The sensor network as claimed in claim 10, wherein the selected gateway of the plurality of gateways relays the message with a selectively delayed wireless beacon.

13. The sensor network as claimed in claim 8, wherein the selected gateway of the plurality of gateways transmits the message to the wireless node in a wireless timeslot allocated by the central unit.

14. The sensor network as claimed in claim 8, wherein each gateway of the plurality of gateways is configured to measure a signal characteristic of a signal received from a wireless node to determine the respective link quality indicator for the respective wireless path.

15. The sensor network as claimed in claim 8, wherein the central unit combines a plurality of messages received by the plurality of gateways from a wireless node to increase reliability of a wireless message from the wireless node.

16. A method of operating a local area network, the method comprising:

transmitting a resource allocation request by a priority network sensor unit in a reserved timeslot in a guaranteed reservation period;

receiving in a central unit the resource allocation request;

transmitting by the central unit a reservation bit map including an allocation of a shared timeslot in response to the resource allocation request; and

receiving in the priority network sensor unit the reservation bit map and in response thereto transmitting data in the allocated shared timeslot.

17. The method as claimed in claim 16, further comprising:

receiving the reservation bit map by a non-priority network sensor unit;

finding an unallocated shared timeslot in the reservation bit map by the non-priority network sensor unit; and

transmitting data in the unallocated shared timeslot by the non-priority network sensor unit.

18. The method as claimed in claim 16, further comprising transmitting a synchronization beacon by the central unit.

19. The method as claimed in claim 16, further comprising transmitting an acknowledgment message by the central unit in response to receiving data from a network sensor unit.

20. The method as claimed in claim 16, wherein the local area network is a wireless sensor network.

21. A method of operating a sensor network, the method comprising:

configuring a plurality of gateways to communicate over wired and wireless portions of the sensor network;

configuring a central unit to communicate with the plurality of gateways over the wired portion of the sensor network;

receiving by the central unit a plurality of link quality indicators from the plurality of gateways for respective wireless paths from a wireless node to the plurality of gateways; and

selecting a gateway of the plurality of gateways by the central unit for relaying a message from the central unit to the wireless node.

22. The method as claimed in claim 21, wherein the selected gateway is selected based on the plurality of link quality indicators.

23. The method as claimed in claim 21, further comprising establishing by the central unit network synchronization for the wireless portion of the sensor network by broadcasting a beacon over the wired portion of the network.

24. The method as claimed in claim 21, wherein the selected gateway transmits the message to the wireless node in a wireless timeslot allocated by the central unit.

25. The method as claimed in claim 21, further comprising combining in the central unit a plurality of messages received by the plurality of gateways from the wireless node to increase message reliability.