Adaptive digital wireless communications network apparatus and process

• US 6,097,707 A
• Filed: 05/19/1995
• Issued: 08/01/2000
• Est. Priority Date: 05/19/1995
• Status: Expired due to Fees

• Current Assignee: James M. Brennan, Migdat I. Hodzic
• Original Assignee: James M. Brennan, Migdat I. Hodzic
• Inventors: Brennan, James M., Hodzic, Migdat I.
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): GALL, LLOYD A
• Application Number:
  US08/444,553
• Time in Patent Office: 1,901 Days
• Field of Search: 370/24, 370/26, 370/29, 370/18, 370/55.3, 370/68.1, 370/77, 370/85.2, 370/79, 370/85.3, 370/84, 370/94.1, 370/94.3, 370/85.7, 370/95.1, 370/85.8, 370/95.2, 370/95.3 , 370/100.1, 370/103, 370/104.1, 370/105, 370/105.1, 379/58, 379/63, 379/59, 340/825.06, 340/825.07, 340/825.08, 455/33.1, 455/33.4, 455/16, 455/15, 455/49.1, 455/51.1, 455/54.2, 455/53.1, 455/54.1, 455/57.1, 375/200, 375/202, 375/205
• US Class Current: 370/321
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 74/0891 for synchronized access

Abstract

A single channel wireless digital communication network [10] has a cellular topology which includes a central unit [12] ("CW") controlling communications with a plurality of remote units [14] ("TU") in a star configuration. Network access is synchronously controlled through a time division multiplexed cycle [20] of variable total duration having an up-link phase [21] of a variable number of fixed size time slots [25, 27, 27a], each pre-assigned by reservation by a remote unit, and a down-link phase [22] of a variable number of variable size slots [31a, 31b] which are adaptively utilized. The CU adaptively manages all slot assignments according to a variety of parameters. RU up-link slot reservations are confirmed by the CU in a variety of ways. During the up-link phase, RU'"'"'s which did not reserve a slot on the previous up-link cycle are temporarily suspended and are then polled or periodically tested for re-entry. A repeater unit [15] ("RU") having a back-to-back coupled ccu-tu pair operates as a minicell within the major cell where major cell coverage is not broad enough to reach all major cell TU'"'"'s.

Claims

1. In a single channel, star configuration, wireless digital communication network of cellular topology wherein a central unit is radio frequency linked to a plurality of remote units and multiple access is synchronously controlled by the central unit through a time division multiplexed cycle,

wherein the improvement comprises:

the cycle having a total cycle time of variable duration divided into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central unit to the remote units and from the remote units to the central unit,

in the up-link phase, a variable number of fixed size data transfer time slots, each pre-assigned on request of a remote unit in an up-link phase of an immediately preceding cycle for use by the requesting remote in uploading data to the central unit in the up-link phase of the next succeeding cycle, and

in the down-link phase, a variable number of variable size data transfer time slots for downloading data from the central unit to selected ones of the remote units.

2. The wireless digital communication network of claim 1 further comprising:

the request being in the form of a flag set in a control field of an information frame having a data packet transmitted by the requesting remote unit to the central unit in the up-link phase of the preceding cycle.

3. The wireless digital communication network of claim 2 further comprising:

a synchronization frame transmitted simultaneously to all of the remote units at the beginning of each up-link data transfer phase of the cycle.

4. The wireless digital communication network of claim 3 wherein the up-link time slots within which each remote unit transmits data information to the central unit are of equal duration.

5. The wireless digital communication network of claim 4 further comprising:

an acknowledgement frame transmitted simultaneously to all of the remote units in the network at the end of the up-link phase of each cycle.

6. The wireless digital communication network of claim 5 further comprising:

a confirmation signal selectively inserted in the data field of an acknowledgement frame addressed to each remote unit for whom a slot has been allocated in the next up-link cycle irrespective of whether an up-link slot was requested by each of them.

7. The wireless digital communication network of claim 6 wherein the location of a remote unit'"'"'s pre-assigned data transfer time slot in a current up-link cycle is a function of the number of remote units scheduled by the central unit for transmission in the current up-link cycle ahead of the remote unit and independent of the number of active stations in the network.

8. The wireless digital communication network of claim 1 further comprising:

a synchronization frame transmitted simultaneously to all of the remote units at the beginning of each up-link data transfer phase of the cycle.

9. The wireless digital communication network of claim 1 wherein the up-link data transfer time slots are of equal duration.

10. The wireless digital communication network of claim 1 further comprising:

an acknowledgement frame transmitted simultaneously to all of the remote units in the network at the end of the up-link phase of each cycle.

11. The wireless digital communication network of claim 10 further comprising:

a confirmation signal selectively inserted in the data field of an acknowledgement frame addressed to each remote unit for whom a slot has been allocated in the next up-link cycle irrespective of whether an up-link slot was requested by each of them.

12. The wireless digital communication network of claim 11 wherein the location of a remote unit'"'"'s pre-assigned data transfer time slot in a current up-link cycle is a function of the number of remote units scheduled by the central unit for transmission in the current up-link cycle ahead of the remote unit and independent of the number of active stations in the network.

13. The wireless digital communication network of claim 1 further comprising:

a confirmation bit being set in an acknowledgement frame, sent by a central unit immediately prior to the down-link phase of the cycle, to indicate to a remote unit for whom the central unit has traffic that a down-link transmission to that remote unit will be made by the central unit in the down-link phase of the current cycle.

14. The wireless digital communication network of claim 1 further comprising:

a suspend mode omitting assignment of an up-link time slot in the up-link phase of a next cycle for any remote unit which did not request one in an up-link phase of a current cycle.

15. The wireless digital communication network of claim 14 further comprising;

a polling signal transmitted in one cycle to each suspended remote unit to indicate reservation of an up-link slot for the remote unit in the next up-link cycle.

16. The wireless digital communication network of claim 15 wherein the polling signal is a confirmation bit set by the central unit in a data field of the acknowledgement frame transmitted by the central unit to all remote units at the end of the up-link phase of the cycle.

17. The wireless digital communication network of claim 14 further comprising;

a polling signal dependent upon an analysis algorithm transmitted every k cycles to each suspended remote unit to indicate reservation of an up-link slot for the remote unit in the next up-link cycle, where k is an integer.

18. The wireless digital communication network of claim 17 wherein the polling signal is a confirmation bit set by the central unit in a data field of the acknowledgement frame transmitted by the central unit to all remote units at the end of the up-link phase of the cycle.

19. The wireless digital communication network of claim 1 further comprising;

the network being a spread-spectrum TDMA communication network and operating in a spread spectrum mode.

20. The wireless digital communication network of claim 1 further comprising;

the central unit and its associated plurality of remote units forming a major cell,

each remote unit and central unit operating in a spread-spectrum mode,

a repeater unit having a local remote unit-local central unit pair coupled back to back to operate as a mini-cell within the major cell.

21. The wireless digital communication network of claim 20 further comprising;

the local remote unit operating with a spread spectrum code which is the same as the spread-spectrum code of the major cell central unit, and the local central unit operating with a different spread spectrum code.

22. In a single channel, star configuration, wireless digital communication network of cellular topology wherein a central unit is radio frequency linked to a plurality of remote units and multiple access is synchronously controlled by the central unit through a time division multiplexed cycle,

wherein the improvement comprises:

the cycle having a total cycle time of variable duration divided into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central units to the remote units and from the remote units to the central units,

in the up-link phase, a variable number of fixed size time slots, each pre-assigned on request of a remote unit in a prior up-link phase for use by the requesting remote unit in uploading information to the central unit in the next up-link phase,

in the down-link phase, a variable number of variable size time slots for downloading information from the central unit to selected ones of the remote units

the central unit and its associated plurality of remote units forming a major cell,

a repeater unit having a local remote unit-local central unit pair coupled back to back to operate as a mini-cell within the major cell, and

frames from the major cell central unit received by the local remote unit of the back to back pair being passed through a UART channel of the local remote unit to a UART channel of the local central unit which in turn acts as a central unit to other remote units in the minicell and vice versa whereby the local remote unit acts as a regular remote unit in the major cell.

23. In a single channel, star configuration, wireless digital communication network of cellular topology wherein a central unit is radio frequency linked to a plurality of remote units and multiple access is synchronously controlled by the central unit through a time division multiplexed cycle,

wherein the improvement comprises:

the cycle having a total cycle time of variable duration divided into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central unit to the remote units and from the remote units to the central unit,

in the up-link phase, a variable number of fixed size data transfer time slots for use in uploading data information to the central unit, and, in the down-link phase, a variable number of variable size time slots for use in downloading data information to the remote units, and

the up-link variable being adaptively allocated by the central unit on demand by remote units with non-requesting units being temporarily suspended from the entire up-link phase of the cycle of the network until a predetermined condition is satisfied.

24. The wireless digital communication network of claim 23 further comprising:

the down-link variables being adaptively allocated by the central unit based on the presence and amount of information for transmission to the remote units.

25. The wireless digital communication network of claim 23 wherein a parameter for allocating the up-link slots includes a request in the form of a flag set in a control field of an information frame having a data packet transmitted by a requesting remote unit to the central unit in the up-link phase of the preceding cycle.

26. In a process of a central unit, radio frequency linked in a star configuration to a plurality of remote units, synchronously controlling multiple access of the remote units to a single channel, wireless, digital, communication network of cellular topology through a cyclic time division multiplexed process,

wherein the improvement comprises the steps of:

providing a total cycle time of variable duration,

dividing the cycle into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central unit to the remote units and from the remote units to the central unit,

pre-assigning each of a variable number of fixed size up-link phase data transfer time slots on reservation by a remote unit in an up-link phase of an immediately preceding cycle for use by the reserving remote unit in uploading data to the central unit in the up-link phase of the next succeeding cycle, and

providing a variable number of variable size down-link phase data transfer time slots for downloading data from the central unit to selected ones of the remote units.

27. The process of claim 26 further comprising the step of:

the reserving remote unit setting a flag in a control field of an information frame having a data packet transmitted to the central unit in the up-link phase of the preceding cycle.

28. The process of claim 27 further comprising the step of:

synchronizing the network with respect to a frame transmitted by the central unit simultaneously to all of the remote units at the beginning of each up-link data transfer phase of the cycle.

29. The process of claim 28 further comprising the step of:

dividing equally in duration the up-link time slots within which each remote unit transmits data information to the central unit.

30. The process of claim 29 further comprising the step of:

confirming the reservation in an acknowledgement frame transmitted simultaneously by the central unit to all of the remote units in the network at the end of the up-link phase of each cycle.

31. The process of claim 30 wherein the confirming step further comprises the step of:

selectively addressing the confirmation signal in a data field of the acknowledgement frame to each remote unit for whom a slot has been allocated in the next up-link cycle irrespective of whether an up-link slot was requested by each of them.

32. The process of claim 31 wherein the confirming step of:

determining a remote unit'"'"'s pre-assigned data transfer time slot in a current up-link cycle as a function of the number of remote units scheduled by the central unit for transmission in the current up-link cycle ahead of the remote unit and independently of the number of active stations in the network.

33. The process of claim 26 further comprising the step of:

synchronizing the network with respect to a frame transmitted by the central unit simultaneously to all of the remote units at the beginning of each data transfer up-link phase of the cycle.

34. The process of claim 26 further comprising the step of:

dividing equally in duration the up-link time slots within which each remote unit transmits data information to the central unit.

35. The process of claim 26 further comprising the step of:

confirming the reservation in an acknowledgement frame transmitted simultaneously by the central unit to all of the remote units in the network at the end of the up-link phase of each cycle.

36. The process of claim 35 wherein the confirming step further comprises the step of:

selectively addressing the confirmation signal in a data field of the acknowledgement frame to each remote unit for whom a slot has been allocated in the next up-link cycle irrespective of whether an up-link slot was requested by each of them.

37. The process of claim 36 wherein the confirming step of:

determining a remote unit'"'"'s pre-assigned time data transfer slot in a current up-link cycle as a function of the number of remote units scheduled by the central unit for transmission in the current up-link cycle ahead of the remote unit and independently of the number of active stations in the network.

38. The process of claim 26 further comprising the step of:

setting a confirmation bit in an acknowledgment frame, sent by a central unit immediately prior to the down-link phase of the cycle, to indicate to a remote unit for whom the central unit has traffic that a down-link transmission to that remote unit will be made by the central unit in the down-link phase of the current cycle.

39. The process of claim 26 further comprising the step of:

suspending any remote unit which did not reserve an up-link time slot in the up-link phase of the preceding cycle by omitting assignment of an up-link time slot in the up-link phase of the succeeding cycle.

40. The process of claim 39 further comprising the step of:

polling each suspended remote unit in one cycle to indicate reservation of an up-link slot for the remote unit in the next up-link cycle.

41. The process of claim 40 wherein the polling step further comprises the step of:

setting a confirmation bit in a data field of an acknowledgement frame transmitted by the central unit to all remote units at the end of the up-link phase of the cycle.

42. The process of claim 39 further comprising the step of:

explicitly polling each suspended remote unit every k cycles to indicate reservation of an up-link slot for the remote unit in the next up-link cycle, where k is an integer.

43. The process of claim 42 wherein the polling step further comprises the step of:

setting a confirmation bit in a data field of an acknowledgement frame transmitted by the central unit to all remote units at the end of the up-link phase of the cycle.

44. The process of claim 26 further comprising the step of:

the network being a spread-spectrum TDMA communication network,

operating the network in a spread spectrum mode.

45. The process of claim 26 further comprising the step of:

configuring the central unit and its associated plurality of remote units as a major cell,

operating each remote unit and central unit in a spread-spectrum mode,

providing a repeater unit having a local remote unit-local central unit pair coupled back to back to operate as a mini-cell within the major cell.

46. The process of claim 45 further comprising the step of:

operating the local remote unit with a spread spectrum code which is the same as the spread-spectrum code of the major cell central unit, and operating the local central unit with a different spread spectrum code.

48. The process of claim 26 further comprising the step of:

the central control unit adaptively allocating the up-link variable on demand by remote units with non-requesting units being temporarily suspended from the entire up-link phase of the cycle of the network until ready to re-enter the network.

47. In a process of a central unit, radio frequency linked in a star configuration to a plurality of remote units, synchronously controlling multiple access of the remote units to a single channel, wireless, digital, communication network of cellular topology through a cyclic time division multiplexed process,

wherein the improvement comprises the steps of:

providing a total cycle time of variable duration,

dividing the cycle into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central unit to the remote units and from the remote units to the central unit,

pre-assigning each of a variable number of fixed size up-link phase time slots on reservation by a remote unit in a prior up-link phase for use by the requesting remote unit in uploading information to the central unit in the next up-link phase,

providing a variable number of variable size down-link phase time slots for downloading data from the central unit to selected ones of the remote units

configuring the central unit and its associated plurality of remote units as a major cell,

providing a repeater unit having a local remote unit-local central unit pair coupled back to back to operate as a mini-cell within the major cell, and

passing frames from the major cell central unit received by the local remote unit of the back to back pair through a UART channel of the local remote unit to a UART channel of the local central unit which in turn operates as a central unit to other remote units in the minicell and vice versa whereby the local remote unit operates as a regular remote unit in the major cell.

49. In a single channel, star configuration, wireless digital communication network of cellular topology wherein a central unit is radio frequency linked to a plurality of remote units and multiple access is synchronously controlled by the central unit through a time division multiplexed cycle,

wherein the improvement comprises:

the cycle having a total cycle time of variable duration divided into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central unit to the remote units and from the remote units to the central unit,

in the up-link phase, a variable number of fixed size data transfer time slots, each pre-assigned on request of a remote unit in one up-link phase of a cycle for use by the requesting remote in uploading data to the central unit in another up-link phase of a cycle, and

in the down-link phase, a variable number of variable size data transfer time slots for downloading data from the central unit to selected ones of the remote units.

50. In a single channel, star configuration, wireless digital communication network of cellular topology wherein a central unit is radio frequency linked to a plurality of remote units and multiple access is synchronously controlled by the central unit through a time division multiplexed cycle,

wherein the improvement comprises:

the cycle having a total cycle time of variable duration divided into two phases, one phase being an up-link phase and the other phase being a down-link phase which follows the up-link phase, each phase having a plurality of time slots in which information is transferred from the central unit to the remote units and from the remote units to the central unit,

in the up-link phase, a variable number of data transfer time slots, each pre-assigned on request of a remote unit in an up-link phase of an immediately preceding cycle for use by the requesting remote in uploading data to the central unit in the up-link phase of the next succeeding cycle, and

in the down-link phase, a variable number of variable size data transfer time slots for downloading data from the central unit to selected ones of the remote units.