Self-adaptive method for the transmission of data, and implementation device

• US 6,094,425 A
• Filed: 01/21/1998
• Issued: 07/25/2000
• Est. Priority Date: 01/21/1997
• Status: Expired due to Term

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Auger, Gerard, Bacelon, Olivier
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US09/009,883
• Time in Patent Office: 916 Days
• Field of Search: 370/319, 370/330, 370/343, 370/344, 370/478, 370/480, 370/481, 370/436, 455/453, 455/450, 455/451, 455/452, 375/202
• US Class Current: 370/330
• CPC Class Codes: H04B 7/2615 using hybrid frequency-time division multiple access [FDMA-TDMA]
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00

Abstract

A dynamic and decentralized self-adaptive method and system including allocation of all time/frequency resources available at a given moment to as many requesting mobile units as are necessary. Transmission between stations is performed by allocation of frequencies. For each frequency allocated, the transmissions are grouped in slots forming frames in a time/frequency space. Each frame includes n slots of a same duration and a same width. The method includes using the allocated transmission frequencies and the frames for each transmission from a station by occupancy of one and the same number of slots according to a modulo p operation. A search is made, during a monitoring procedure, for free slots to determine parameters of occupation of a transmission as a function of the state of occupancy of the frames of the time/frequency space existing before the transmission. With the noted method and system, simultaneous operation of a large number of stations, without planning, initial data or centralized management, while at the same time maintaining compatibility with waveforms of conventional systems and methods, is enabled.

Claims

1. A self-adaptive method for the transmission of data between stations of a decentralized radio system, comprising:

allocating transmissions of information between the stations in an available frequency band;

grouping the transmissions in slots forming frames in time/frequency space, each frame comprising n slots of a same duration and a same width and being carried by an allocated frequency;

using the allocated transmission frequencies successively in time;

using the frames for each transmission from a station by occupancy of one and the same number of slots on the frames according to a modulo p operation, p being limited by an upper value; and

making a search, during a monitoring procedure, for free slots to determine parameters of occupancy of a future transmission made from a station, as a function of a state of occupancy of the frames of the time/frequency space existing before a transmission.

2. The method of claim 1, wherein the monitoring procedure, includes,

listening on a given frequency the transmitting stations which indicate, by a message in at least one of occupied slots per occupied frame, a state of occupancy of the time/frequency space,

wherein each station defines a table of occupancy according to a state of occupancy and each station chooses, according to the table, one or more slots identified as being free by each station and by the other stations whose table of occupancy is within range of communication.

3. The method of claim 2, wherein, with each station monitoring interrupted frequency hop intervals, the method includes interrupting the corresponding monitoring hop interval to permit reception of the slots as soon as slots carrying information intended for a station are received.

4. The method of claim 1, including setting the occupancy modulo value p to a prime number within a number q of allocated frequencies,

wherein frames comprising pn slots enable optimal occupancy.

5. The method of claim 4, including providing a monitoring frequency that lasts at least qnpLT to receive at least one slot from all transmitting stations that transmit on frames pn, when the number p is a prime number within the number q, where T is a slot duration and L is a number of the transmitting stations.

6. The method of claim 3, including conditioning a monitoring frequency based on a detection of jamming induced by an alarm.

7. The method of claim 1, including using the allocated frequencies in an unspecified temporal order or in a temporal order that is periodically modified pseudo-randomly.

8. The method of claim 1, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

9. The method of claim 1, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristic of a transmission method used.

10. The method of claim 1, wherein when a number of transmission slots required becomes greater than number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

11. The method of claim 10, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

12. The method of claim 2, including setting the occupancy modulo value p to a prime number within a number q of allocated frequencies,

wherein frames comprising pn slots enable optimal occupancy.

13. The method of claim 12, including providing a monitoring frequency that lasts at least qnpLT to receive at least one slot from all transmitting stations that transmit on frames pn, when the number p is a prime number within the number q, where T is a slot duration and L is a number of the transmitting stations.

14. The method of claim 2, including using the allocated frequencies in an unspecified temporal order or in a temporal order that is periodically modified pseudo-randomly.

15. The method of claim 2, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

16. The method of claim 2, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

17. The method of claim 2, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

18. The method of claim 17, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

19. The method of claim 3, including setting the occupancy modulo value p to a prime number within a number q of allocated frequencies,

wherein frames comprising pn slots enable optimal occupancy.

20. The method of claim 19, including providing a monitoring frequency that lasts at least qnpLT to receive at least one slot from all transmitting stations that transmit on frames pn, when the number p is a prime number within the number q, where T is a slot duration and L is a number of the transmitting stations.

21. The method of claim 3, including using the allocated frequencies in an unspecified temporal order or in a temporal order that is periodically modified pseudo-randomly.

22. The method of claim 3, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

23. The method of claim 3, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

24. The method of claim 3, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

25. The method of claim 24, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

26. The method of claim 6, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

27. The method of claim 6, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

28. The method of claim 6, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

29. The method of claim 28, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

30. The method of claim 4, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

31. The method of claim 4, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

32. The method of claim 4, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

33. The method of claim 32, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

34. The method of claim 5, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

35. The method of claim 5, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

36. The method of claim 5, including using the allocated frequencies in an unspecified temporal order or in a temporal order that is periodically modified pseudo-randomly.

37. The method of claim 5, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

38. The method of claim 37, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

39. The method of claim 4, including using the allocated frequencies in an unspecified temporal order or in a temporal order that is periodically modified pseudo-randomly.

40. The method of claim 7, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

41. The method of claim 7, including organizing the frames to all have a same number n of slots and so as to occupy an entire time/frequency space corresponding to an orthogonal pavement block pattern.

42. The method of claim 7, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

43. The method of claim 42, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

44. The method of claim 8, including organizing a number of slots occupied per frame and a duration of the occupied slots depending on a mean bit rate defined by a modulation method used, and

organizing the slot occupancy depending on a characteristics of a transmission method used.

45. The method of claim 8, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

46. The method of claim 45, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

47. The method of claim 9, wherein when a number of transmission slots required becomes greater than a number of slots available for a given station, the method includes computing a density of occupancy of each slot by weighting the occupancy of the slots by a power of a signal directly received by a station making a transmission.

48. The method of claim 47, wherein the weighting is carried out based on power received from stations which indicate, in a message, that the stations are also observing an occupied slot, and

the method includes making a choice of the transmission slots based on a random draw from transmission slots whose occupancy density is lowest.

49. The method of claim 6, including using the allocated frequencies in an unspecified temporal order or in a temporal order that is periodically modified pseudo-randomly.

50. A wireless communications system, comprising:

a receiver configured to receive a signal representing a reception frequency picked up by a station, the receiver transmitting a demodulated slot occupancy signal to a network analyzer;

a computing unit configured to reset a local time base based on a received signal indicating reception of frequencies;

a table unit coupled to the network analyzer and configured to receive a signal indicating a level of power received during demodulated slots and compute a table of occupancy;

a reception frequency management unit configured to receive a signal of a level of power received outside the demodulated slots and mange frequencies received to estimate jamming of a monitoring frequency used;

a slot unit configured to compute transmission slots for a station locally attached thereto;

a transmission frequency management unit coupled to the table unit; and

a transmitter;

wherein the slot unit transmits information to the transmission frequency management unit, which orders the transmitter to transmit at a frequency Fe.

51. The system of claim 50, wherein identification of the transmission slots is determined by the computation unit from a number of necessary slots defined as a function of a desired service and the occupancy of the slots determined by the table unit,

a choice of the transmission frequency is then made by the transmission frequency management unit as a function of the local time base set by the computation unit and the transmission slots defined by the computation unit, and

the transmission frequency management unit then orders the transmission by the transmitter.

52. The system of claim 50, wherein the reception and transmission frequency management units and the computation unit comprise a single processor, assisted by a programmable network of ports for management of time bases.

53. The system of claim 52 wherein, to optimize a time/frequency space occupancy, transmission time bases of all stations are synchronized to a period T.

54. The system of claim 53, wherein the synchronization is based on a common reference clock, external to the system.

55. The system of claim 53, wherein the synchronization is performed by setting a time base of each station in relation to a time base of a station most in advance.

56. The system of according to claim 53, wherein the synchronization is performed by computing a mean of reception times of the slots and resetting a time base of a station in relation to the mean.

57. The system of claim 53, wherein the synchronization is performed by division of an elementary time interval into sub-intervals, and

the transmission being then programmed to occur in the subinterval modulo T in which there are received a maximum number of slots at a moment corresponding to a mean of moments of reception of slots, in an event of equality between several sub-intervals, the subinterval most in advance being selected.

58. The system of any of claims 50 to 57, wherein stations have available common module p frame clocks to determine free slots with respect to a transmission, to enable the transmission slots to be deduced from reception of only one slot, whereby it is then possible to deduce information of recurrence of transmission from signals received by the receiver.