TIME SLOT SYNCHRONIZED, FLEXIBLE BANDWIDTH COMMUNICATION SYSTEM

• US 20090257422A1
• Filed: 03/02/2009
• Published: 10/15/2009
• Est. Priority Date: 03/10/2008
• Status: Active Grant

• Current Assignee: Comtech Mobile Datacom Corporation (Comtech Telecommunications Corporation)
• Original Assignee: Comtech Mobile Datacom Corporation (Comtech Telecommunications Corporation)
• Inventors: SMITH, R. Clayton, JORDAN, Luis G., MCDERMOTT, Scott A.
• Granted Patent: US 8,284,749 B2
• Time in Patent Office: Days
• US Class Current: 370/345
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

One or more frame slots to each transceiver are allocated for communication within each message cycle. The number of frame slots allocated can be dynamically adjusted to accommodate variable traffic loads per transceiver, and an offset of the frame slots within the message cycle is preferably predefined to provide a uniform distribution among the transceivers. The design of the transceiver is independent of the particular application, having at least one programmable parameter that controls the number of frame slots allocated within the message cycle. By controlling the number of frame slots allocated to a transceiver, the amount of inactive time, and hence battery life, can be controlled. When a conflict occurs among multiple transceivers having pending messages at the same frame slot, the allocation of the frame slot to a transceiver is based at least in part on the resultant lag time to each transceiver.

Claims

1. A communication system comprising:

a base station that is configured to communicate messages in a plurality of frame slots within a message cycle, and

a plurality of transceivers, each transceiver being configured to be activated at an assigned frame slot offset and at an assigned frame slot interval within the message cycle, to facilitate communication of messages between the base station and the transceiver during a number of frame slots within the message cycle based on the offset and interval, at least two of the transceivers having different frame slot offsets and frame slot intervals.

2. The communication system of claim 1, wherein the base station is configured to assign the frame slot interval to at least one transceiver of the plurality of transceivers, based on a bandwidth parameter associated with the at least one transceiver.

3. The communication system of claim 2, wherein the offset of each transceiver is based on a substantially unique identifier of the transceiver.

4. The communication system of claim 3, wherein the unique identifier corresponds to one of a serial number and a MAC address.

5. The communication system of claim 1, wherein the offset of each transceiver is based on a substantially unique identifier of the transceiver.

6. The communication system of claim 1, wherein multiple transceivers share a common offset, and each message includes an address field that identifies one or more intended recipients of the message.

7. The communication system of claim 1, wherein the base station is configured to communicate an indicator of an intended activation rate to one or more of the transceivers, and the transceivers are configured to modify the interval based on the indicator of the intended activation rate.

8. The communication system of claim 1, wherein the base station is configured to transmit the messages based on a single DSS spreading code, and each of the transceivers are configured to decode the messages based on this single DSS spreading code and a substantially fixed code-phase that is associated with each transceiver.

9. The communication system of claim 8, wherein a common code-phase is concurrently associated with multiple transceivers.

10. The communication system of claim 9, wherein an assignment of the code-phase associated with each transceiver is such that different code-phases are assigned to transceivers having a common offset.

11. The communication system of claim 10, wherein the assignment of the code-phase and the fixed identifier of the transceiver is based on a substantially unique fixed identifier of each transceiver.

12. The communication system of claim 11, wherein the assignment of the code-phase is based on a first set of bits of the fixed identifier, and the assignment of the offset is based on a second set of bits of the fixed identifier.

13. The communication system of claim 1, wherein the base station is configured to prioritize the messages based on a latency factor that is based on the interval assigned to each corresponding transceiver.

14. The communication system of claim 1, wherein the base station is coupled to the transceivers via a satellite.

15. The communication system of claim 1, wherein the base station is configured to transmit synchronization messages that serve to maintain synchronization between the base station and each transceiver.

16. A device for operation in a network wherein transmissions are scheduled to occur at regular frame slots within a message cycle, comprising:

a transceiver, and

a timer,

wherein;

the timer is configured to activate the transceiver at a defined activation rate to facilitate reception during one or more defined frame slots within the message cycle,

the transceiver is configured to synchronize with the one or more defined frame slots based on a synchronization signal in the transmission within the one or more frame slots, and to decode one or more messages within the frame slot,

the transceiver is configured to enter a substantially inactive state between the one or more defined frame slots, and

the one or more defined frame slots are based on the defined activation rate and a defined offset associated with the transceiver.

17. The device of claim 16, wherein the defined offset is based on a substantially unique fixed identifier of the transceiver.

18. The device of claim 17, wherein the fixed identifier corresponds to one of a serial number and a MAC address.

19. The device of claim 16, including a controller that is configured to modify the defined activation rate upon receipt of a directive from a controlling base station.

20. The device of claim 16, wherein a total number of frame slots per message cycle is an integer multiple of the defined activation rate.

21. The device of claim 16, wherein the transceiver is configured to operate at an assigned code-phase of a DSS spreading code.

22. The device of claim 21, wherein the assigned code-phase is based on a substantially unique fixed identifier of the transceiver.

23. The device of claim 16, wherein the transceiver is configured to enter the substantially inactive state upon receipt of a message addressed to the device.

24. The device of claim 16, wherein the transceiver is configured to enter the substantially inactive state based on an indicator of a determined order of messages within the one or more defined frame slots.

25. A base station comprising:

a timer that is configured to partition a message cycle into a number of frame slots,

a controller that is configured to;

receive messages from one or more service units, each message being addressed to one or more remote devices,

allocate each message to one or more slot queues based on the addressed remote device, and

transmit the messages in each slot queue during a corresponding frame slot,

wherein

each of the one or more remote devices has an associated frame slot offset and frame slot interval, and the controller allocates each message based on one or more defined frame slots based on the offset and interval, and

at least two of the remote devices have differing frame slot offsets and frame slot intervals.

26. The base station of claim 25, wherein the base station is configured to assign the frame slot interval of each remote device based on a desired duty cycle of the remote device.

27. The base station of claim 26, wherein the desired duty cycle of the remote device is based on at least one of a desired bandwidth and a desired power consumption at the remote device.

28. The base station of claim 25, wherein the frame slot offset of each remote device is based on a substantially unique identifier of the remote device.

29. The base station of claim 25, wherein the controller is configured to prioritize the messages allocated to each slot queue that exceeds a capacity of the frame slot, based on a latency factor that is based on the frame slot interval of each addressed remote device.

30. The base station of claim 25, including a transmitter that is configured to transmit the messages based on a single DSS spreading code and a code-phase of the spreading code associated with each addressed remote device.

31. The base station of claim 30, wherein a common code-phase is concurrently associated with multiple remote devices, and an assignment of the code-phase associated with each transceiver is such that different code-phases are assigned to transceivers having a common offset.

32. The base station of claim 30, wherein an assignment of the code-phase and the offset associated with each remote device are based on a substantially unique fixed identifier of each remote device.

33. The base station of claim 32, wherein the code-phase is based on a first set of bits of the fixed identifier, and the offset is based on a second set of bits of the fixed identifier.

34. The base station of claim 25, including a transmitter that is configured to communicate with the remote devices via a satellite.

35. The base station of claim 25, including a transmitter that is configured to transmit synchronization messages that serve to maintain synchronization between the base station and each remote device.

36. A method comprising:

partitioning a message cycle into a number of frame slots,

receiving messages from one or more service units, each message being addressed to one or more remote devices,

allocating each message to one or more slot queues based on the addressed remote device, and

transmitting the messages in each slot queue during a corresponding frame slot,

wherein

each of the one or more remote devices has an associated frame slot offset and frame slot interval, and the controller allocates each message based on one or more defined frame slots based on the offset and interval, and

at least two of the remote devices have differing frame slot offsets and frame slot intervals.

37. The method of claim 36, including assigning the frame slot interval to each remote device based on a desired duty cycle of the remote device.

38. The method of claim 37, wherein the desired duty cycle of the remote device is based on at least one of a desired bandwidth and a desired power consumption at the remote device.

39. The method of claim 36, wherein the frame slot offset of each remote device is based on a substantially unique identifier of the remote device.

40. The method of claim 36, including prioritizing the messages allocated to each slot queue when an amount of messages in the queue exceeds a capacity of the frame slot, based on a latency factor that is based on the frame slot interval of each addressed remote device.

41. The method of claim 36, including transmitting the messages based on a single DSS spreading code and a code-phase of the spreading code associated with each addressed remote device.

42. The method of claim 41, wherein a common code-phase is concurrently associated with multiple remote devices, and an assignment of the code-phase associated with each transceiver is such that different code-phases are assigned to transceivers having a common offset.

43. The method of claim 41, including assigning the code-phase and the offset associated with each remote device based on a substantially unique fixed identifier of each remote device.

44. The method of claim 43, wherein the code-phase is based on a first set of bits of the fixed identifier, and the offset is based on a second set of bits of the fixed identifier.

45. The method of claim 36, including communicating with the remote devices via a satellite.

46. The method of claim 36, including arranging the messages in each slot queue in a determined order of transmission.

47. The method of claim 46, wherein the order of transmission is based upon a priority established among the one or more service units.