Media access control and distributed data processing using mediation devices in an asynchronous network

• US 20040042501A1
• Filed: 05/22/2003
• Published: 03/04/2004
• Est. Priority Date: 05/23/2002
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Huang, Jian, Shi, Qicai, Hester, Lance Eric, Callaway, Edgar Herbert Jr.
• Granted Patent: US 7,492,773 B2
• Time in Patent Office: Days
• US Class Current: 370/509
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A low power consumption protocol for low power communication devices attached to an asynchronous network is described. In this protocol, one or more mediation devices (MDs) facilitate data processing capabilities in the network, whether in a dedicated MD or distributed MD network environment. These capabilities may be provided by the functions of packet caching, removal of replicated packets, and multiple communication types performed by the one or more MDs in accordance with a common synchronization schedule (2510) managed by the one or more MDs and communicated to other devices in the network (2530).

Claims

1. A method of facilitating communications between one or more of a plurality of communication devices of an asynchronous network, comprising:

establishing a common synchronization schedule of the asynchronous network managed by a mediation device of the network; and

the mediation device transmitting a message received from a first communication device of the plurality of communication devices to one or more of the plurality of communication devices in accordance with the common synchronization schedule and a communication request received from the first communication device.

2. The method of claim 1, wherein establishing the common synchronization schedule comprises:

the mediation device transmitting a synchronization message to the plurality of communication devices when the mediation device knows the plurality of communication devices will be able to receive the synchronization message; and

the mediation device transmitting the common synchronization schedule to the plurality of communication devices in accordance with the synchronization message.

3. The method of claim 2, further comprising:

each of the plurality of communication devices acknowledging receipt of the common synchronization schedule if the common synchronization schedule is received.

4. The method of claim 3, wherein acknowledging receipt of the common synchronization schedule comprises:

each of the plurality of communication devices that received the common synchronization schedule transmitting an acknowledge message at a random time during a receive period of the mediation device that follows the transmission of the common synchronization schedule by the mediation device.

5. The method of claim 3, wherein acknowledging receipt of the common synchronization schedule comprises:

each of the plurality of communication devices that received the common synchronization schedule transmitting an acknowledge message to the mediation device at a predetermined beacon transmission slot.

6. The method of claim 3, wherein acknowledging receipt of the common synchronization schedule comprises:

each of the plurality of communication devices that received the common synchronization schedule transmitting a regularly scheduled beacon transmission of the communication device following receipt of the common synchronization schedule.

7. The method of claim 1, further comprising:

the mediation device caching data of the message in a memory for a period of time; and

upon a second communication device of the plurality of communication devices requesting the data within the period of time, the mediation device transmitting the data to the second communication device without requesting the data from the first communication device.

8. The method of claim 1, further comprising:

if data of the message has been previously cached in memory, the mediation device discarding the message and sending the cached data to the one or more of the plurality of communication devices.

9. The method of claim 1, wherein the mediation device transmits the message received from the first communication device to a second communication device in accordance with the common synchronization schedule and a unicast communication request received from the first communication device.

10. The method of claim 1, wherein the mediation devices transmits the message received from the first communication device to multiple communication devices of the plurality of communication devices in accordance with the common synchronization schedule and a multicast communication request received from the first communication device.

11. The method of claim 10, wherein the multiple communication devices are of a group identified by a group address in the multicast communication request from the first communication device and the MD transmits the message to the group address.

12. The method of claim 1, wherein the mediation devices transmits the message received from the first communication device to the plurality of communication devices in accordance with the common synchronization schedule and a broadcast communication request received from the first communication device.

13. An asynchronous communications network, comprising:

a plurality of communication devices;

a mediation device (MD) operable to facilitate communications between a first communication device and one or more communication devices of the plurality of communication devices;

wherein the MD facilitates communications between the first communication device and the one or more communication devices in accordance with a common synchronization schedule of the asynchronous network managed by the MD.

14. The network of claim 13, wherein the MD transmits a message received from the first communication device to the one or more communication devices in accordance with the common synchronization schedule and a communication request received by the MD from the first communication device.

15. The network of claim 14, wherein the communication request is a unicast communication request from the first communication device to transmit the message to a second communication device of the plurality of communication devices and the MD transmits the message to the second communication device in accordance with the common synchronization schedule.

16. The network of claim 14, wherein the communication request is a multicast communication request from the first communication device to transmit the message to multiple communication devices of the plurality of communication devices and the MD transmits the message to the multiple communication devices in accordance with the common synchronization schedule.

17. The network of claim 16, wherein the multiple communication devices are of a group identified by a group address in the multicast communication request from the first communication device and the MD transmits the message to the group address.

18. The network of claim 14, wherein the communication request is a broadcast communication request from the first communication device to transmit the message to the plurality of communication devices and the MD transmits the message to the plurality of communication devices in accordance with the common synchronization schedule.

20. The network of claim 13, wherein the asynchronous network operates in one of a distributed mode with the MD being a second communication device of the plurality of communication devices and a dedicated mode with the MD being a dedicated mediation device in the asynchronous network.

21. The network of claim 13, wherein the common synchronization schedule is established and communicated to the plurality of communication devices by the MD.

22. The network of claim 13, wherein the MD establishes the common synchronization schedule in response to a communication request received from the first communication device.

23. The network of claim 13, wherein the MD establishes the common synchronization schedule upon becoming the mediation device.

24. The network of claim 13, wherein is MD is operable to cache data from previous transmissions in the network in a memory element, and

wherein upon receiving a request from a requesting communication device of the plurality of communication devices for data cached in the memory element, the MD transmits the data from the memory element to the requesting communication device.

25. The network of claim 13, wherein if data from the first communication device to be transmitted to a second communication device of the plurality of communication devices has been cached in a memory element, the mediation device discards the data from the first communication device.

26. A first communication device of a plurality of communication devices operable to facilitate communications between the plurality of communication devices in an asynchronous network, comprising:

a processing and control element that establishes and manages a common synchronization schedule of the asynchronous network;

a receiver, coupled to and controlled by the processing and control element, that receives a communication request to send a message to one or more of the plurality of communication devices; and

a transmitter, coupled to and controlled by the processing and control element, that in response to the receiver receiving the communication request transmits the message to the one or more communication devices in accordance with the common synchronization schedule.

27. The device of claim 26, wherein the common synchronization schedule is established by the processing and control element causing the transmitter to transmit a synchronization message to the plurality of communication devices when the first communication device knows the plurality of communication devices will be able to receive the synchronization message and causing the transmitter to transmit the common synchronization schedule to the plurality of communication devices in accordance with the synchronization message.

28. The device of claim 27, wherein the receiver further receives one or more acknowledgements from one or more of the plurality of communication devices that received the common synchronization schedule.

29. The device of claim 27, wherein the processing and control element establishes the common synchronization schedule in response to a communication request received from a second communication device.

30. The device of claim 26, wherein the communication request is a unicast communication request and the transmitter transmits the message to a second communication device in accordance with the unicast communication request and the common synchronization schedule.

31. The device of claim 26, wherein the communication request is a multicast communication request and the transmitter transmits the message to multiple communication devices of the plurality of communication devices in accordance with the multicast communication request and the common synchronization schedule.

32. The device of claim 26, wherein the communication request is a broadcast communication request and the transmitter transmits the message to the plurality of communication devices in accordance with the broadcast communication request and the common synchronization schedule.

33. The device of claim 26, wherein the first communication device facilitates communications between the plurality of communication devices during one or a distributed mode of operation and a dedicated mode of operation.

34. The device of claim 26, further comprising:

a memory element of the first communication device,

wherein the processing and control element caches data of the message in the memory element for a period of time; and

upon a second communication device of the plurality of communication devices requesting the data within the period of time, the processing and control element causes the transmitter to transmit the data to the second communication device without requesting the data from the first communication device.

35. The device of claim 26, further comprising:

a memory element of the first communication device,

wherein if data of the message has been previously cached in the memory element, the processing and control element discards the message and causes the transmitter to transmit the cached data to one or more of the plurality of communication devices.

36. The device of claim 26, wherein the processing and control element causes the transmitter to transmit the common synchronization schedule to the plurality of communication devices by the MD.

37. A method for facilitating communications between one or more of a plurality of communication devices of an asynchronous network, comprising:

a first communication device of the plurality of communication devices transmitting a communication request to a mediation device to transmit a message to one or more of the one or more communication devices;

the mediation device receiving the communication request from the first communication device; and

the mediation device transmitting the message to the one or more communication devices in accordance with a common synchronization schedule of the asynchronous network managed by the mediation device.

38. The method of claim 37, wherein establishing the common synchronization schedule further comprises:

the mediation device transmitting a synchronization message to the plurality of communication devices when the mediation device knows the plurality of communication devices will be able to receive the synchronization message; and

the mediation device transmitting the common synchronization schedule to the plurality of communication devices in accordance with the synchronization message.

39. The method of claim 38, further comprising:

each of the plurality of communication devices that receives the common synchronization schedule transmitting an acknowledge message at a random time during a receive period of the mediation device that follows the transmission of the common synchronization schedule by the mediation device.

40. The method of claim 38, further comprising:

each of the plurality of communication devices that receives the common synchronization schedule transmitting an acknowledge message to the mediation device during a predetermined transmission slot.

41. The method of claim 38, further comprising:

each of the plurality of communication devices that receives the common synchronization schedule transmitting a regularly scheduled transmission following receipt of the common synchronization schedule.

42. The method of claim 38, wherein the communication request is a unicast communication request and further comprising:

the mediation device transmitting the message to a second communication device in accordance with the common synchronization schedule.

43. The method of claim 38, wherein the communication request is a multicast communication request and further comprising:

the mediation device transmitting the message to multiple communication devices in accordance with the common synchronization schedule.

44. The method of claim 38, wherein the communication request is a broadcast communication request and further comprising:

the mediation device transmitting the message to the plurality of communication devices in accordance with the common synchronization schedule.

45. Computer-readable media tangibly embodying a program of instructions executable by a computer to facilitate communications between one or more of a plurality of communication devices of an asynchronous network, the method comprising:

establishing a common synchronization schedule of the asynchronous network managed by a mediation device of the network; and

the mediation device transmitting a message received from a first communication device of the plurality of communication devices to one or more of the plurality of communication devices in accordance with the common synchronization schedule and a communication request received from the first communication device.

46. Computer-readable media tangibly embodying a program of instructions executable by a computer to facilitate communications between one or more of a plurality of communication devices of an asynchronous network, the method comprising:

a first communication device of the plurality of communication devices transmitting a communication request to a mediation device to transmit a message to one or more of the one or more communication devices;

the mediation device receiving the communication request from the first communication device; and

the mediation device transmitting the message to the one or more communication devices in accordance with a common synchronization schedule of the asynchronous network managed by the mediation device.

47. A method of facilitating communications between one or more of a plurality of communication devices of an asynchronous network, comprising:

a mediation device receiving a communication request from a first communication device of the plurality of communication devices to transmit data to a second communication device of the plurality of communication devices;

the mediation device determining whether the requested data has been cached in memory;

if the requested data has been cached in memory, the mediation device transmitting the requested data from memory the second communication device.

48. The method of claim 47, further comprising:

the mediation device discarding the data from the first communication device if the requested data has been cached in the memory.

49. The method of claim 47, further comprising:

if the requested data has not been cached in memory, the mediation device transmitting the data from the first communication device to the second communication device.

50. An asynchronous communications network, comprising:

a plurality of communication devices;

a mediation device (MD) operable to facilitate communications between a first communication device and one or more communication devices of the plurality of communication devices and operable to cache data from previous transmission in the network in a memory element;

wherein the MD upon receiving a request from a first communication device of the plurality of communication devices to transmit data cached in the memory element to a second communication device of the plurality of communication devices, transmits the cached data from the memory element to the second communication device.

51. A first communication device of a plurality of communication devices operable to facilitate communications between the plurality of communication devices in an asynchronous network, comprising:

a processing and control element that manages communications between the plurality of communications devices;

a receiver, coupled to and controlled by the processing and control element, that receives a communication request to send data to one or more of the plurality of communication devices;

a transmitter, coupled to and controlled by the processing and control element; and

a memory element,

wherein in response to the receiver receiving a request to transmit data that is already cached in the memory element, the processing and control element transmitting the cached data.

52. The device of claim 51, further comprising:

discarding the data received by the receiver with the request.