Medium access control in industrial and automotive wireless with combined wired and wireless sensor networks
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.
1. A local area network, comprising:
a central transceiver configured to
receive a resource allocation request in a first reserved timeslot in a guaranteed reservation period from a first priority network sensor unit, the first reserved timeslot different from a second reserved timeslot in the guaranteed reservation period assigned to a second priority network sensor unit,
transmit a reservation bit map including an allocation of a first shared timeslot in response to the resource allocation request, and
receive data in the allocated first shared timeslot from the first priority network sensor unit.
2. The local area network as claimed in claim 1 , wherein the central transceiver is further configured to receive data from a non-priority network sensor unit in a shared time slot that is indicated by the reservation bit map to be unallocated.
3. The local area network as claimed in claim 2 , wherein the central transceiver is configured to receive the data in the shared time slot that is indicated to be unallocated using a carrier sense multiple access collision avoidance communication mode.
4. The local area network as claimed in claim 1 , wherein the central transceiver 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 transceiver is configured to transmit 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. The local area network as claimed in claim 1 ,
wherein the central transceiver is further configured to
communicate with a plurality of gateways over a wired portion of the local area network,
receive 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
select a gateway of the plurality of gateways for relaying a message from the central transceiver to the wireless node.
9. The local area network as claimed in claim 8 , wherein the central transceiver 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 local area network as claimed in claim 8 , wherein the central transceiver establishes network synchronization for a wireless time division multiple access communication mode by broadcasting a beacon over the wired portion of the local area network.
11. The local area network as claimed in claim 8 , wherein the central transceiver is further configured to allocate a wireless timeslot for the selected gateway of the plurality of gateways to transmit the message to the wireless node.
12. The local area network as claimed in claim 8 , wherein the central transceiver is configured to combine 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.
13. The local area network of claim 1 , wherein the a central transceiver is further configured to receive a further resource allocation request in the second reserved timeslot in the guaranteed reservation period from the second priority network sensor unit;
transmit the reservation bit map including an allocation of a second shared timeslot in response to the further resource allocation request; and
receive data in the allocated second shared timeslot from the second priority network sensor unit.
14. A method of operating a local area network, the method comprising:
receiving, by a central transceiver, a resource allocation request from a first priority network sensor unit in a first reserved timeslot in a guaranteed reservation period, the first reserved timeslot different from a second reserved timeslot in the guaranteed reservation period assigned to a second priority network sensor unit;
transmitting a reservation bit map including an allocation of a first shared timeslot in response to the resource allocation request; and
receiving data in the allocated first shared timeslot from the first priority network sensor unit.
15. The method as claimed in claim 14 , further comprising receiving data from a non-priority network sensor unit in a shared timeslot that is indicated to be unallocated according to the reservation bit map.
16. The method as claimed in claim 14 , further comprising transmitting a synchronization beacon by the central transceiver.
17. The method as claimed in claim 14 , further comprising transmitting an acknowledgment message by the central transceiver in response to receiving data from a network sensor unit.
18. The method as claimed in claim 14 , wherein the local area network is a wireless sensor network.
19. The method as claimed in claim 14 , further comprising:
configuring the central transceiver to communicate communication with a plurality of gateways over a wired portion of the sensor network, wherein the gateways are configured to communicate over wired and wireless portions of the local area network;
receiving, by the central transceiver, 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 transceiver for relaying a message from the central transceiver to the wireless node.
20. The method as claimed in claim 19 , wherein the selected gateway is selected based on the plurality of link quality indicators.
21. The method as claimed in claim 19 , further comprising establishing, by the central transceiver, network synchronization for the wireless portion of the sensor network by broadcasting a beacon over the wired portion of the network.
22. The method as claimed in claim 19 , further comprising combining, in the central transceiver, a plurality of messages received by the plurality of gateways from the wireless node to increase message reliability.
23. A communication unit for a sensor network, the communication unit comprising:
a processor; and
a wireless transceiver coupled to the processor, the communication unit configured to
receive a resource allocation request in a first reserved timeslot in a guaranteed reservation period from a first priority network sensor unit, the first reserved timeslot different from a second reserved timeslot in the guaranteed reservation period assigned to a second priority network sensor unit,
transmit a reservation bit map including an allocation of a first shared timeslot in response to the resource allocation request, and
receive data in the allocated first shared timeslot from the first priority network sensor unit.
24. The communication unit of claim 23 , further comprising a wire line transceiver configured to communication with a central unit over a wired portion of the sensor network.