Voice-data integrated multiaccess by self-reservation and stabilized aloha contention

• US 6,963,545 B1
• Filed: 06/19/2000
• Issued: 11/08/2005
• Est. Priority Date: 10/07/1998
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Ho, Jin-Meng
• Primary Examiner(s): Duong, Frank
• Assistant Examiner(s): Jagannathan, Melanie
• Application Number:
  US09/597,392
• Time in Patent Office: 1,968 Days
• Field of Search: 370335-348, 370441-443, 370/462, 370/282, 370/310, 370/330, 455/452.2
• US Class Current: 370/282
• CPC Class Codes: H04W 28/20 Negotiating bandwidth
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0838 using contention-free random access [CFRA]
• CPC Class Codes: H04W 74/0875 with assigned priorities based access

Abstract

A multiple access communication protocol that includes an uplink and a downlink channel is disclosed. The uplink channel has a plurality of frames, such that each frame has a first selectable number of minislots and a second selectable number of slots. A reservation request of a first type is sent into a first selected minislot of a selected frame of the uplink channel when information of a first type is to be sent. The reservation request of the first type requests an assignment for at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame. A reservation request of a second type is sent into a second selected minislot of the selected frame when the second selected minislot is available in the selected frame and when information of a second type is to be sent. The reservation request of the second type requests an assignment of at least one slot for transmitting information of the second type in at least one frame that is subsequent to the selected frame, and contends for the second selected minislot based on a pseudo-Bayesian Aloha algorithm. The downlink channel contains a feedback message that occurs prior to the end of the selected frame of the uplink channel. The feedback message includes minislot assignment information for sending reservation requests of the first and the second type and slot assignment information for transmitting information of the first and the second type, minislot contention information for the reservation requests of the second type sent in the selected frame, and reservation backlog information for an estimated number of reservation requests of the second type pending at a beginning of the selected frame.

Claims

1. A multiple access communication protocol, comprising:

an uplink channel having a plurality of frames, each frame having a first selectable number of minislots and a second selectable number of slots, a reservation request of a first type being sent into a first selected minislot of a selected frame of the uplink channel when information of a first type is to be sent, the reservation request of the first type requesting an assignment for at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame, a reservation request of a second type being sent into a second selected minislot of the selected frame when the second selected minislot is available in the selected frame and when information of a second type is to be sent, the reservation request of the second type requesting an assignment of at least one slot for transmitting information of the second type in at least one frame that is subsequent to the selected frame, the reservation request of the second type contending for the second selected minislot based on a pseudo-Bayesian Aloha algorithm; and

a downlink channel containing a feedback message having minislot assignment information for sending reservation requests of the first and the second type, slot assignment information for transmitting information of the first and the second type, minislot contention information for the reservation requests of the second type sent in the selected frame, and reservation backlog information for an estimated number of reservation requests of the second type pending at a beginning of the selected frame, the feedback message occurring prior to an end of the selected frame of the uplink channel.

2. The multiple access communication protocol according to claim 1, wherein the reservation requests of the second type are sent into the second selected minislots, each second selected minislot being selected independently and at random with equal probability from a plurality of minislots available for sending the reservation requests of the second type.

3. The multiple access communication protocol according to claim 2, wherein the reservation request message of the second type is sent into the second selected minislot with a probability that is based on a number of minislots available in the selected frame for sending reservation requests of the second type and on an estimated backlog of messages of the second type pending at a beginning of the selected frame.

4. The multiple access communication protocol according to claim 3, wherein the probability is determined as:

p=min(1,N_R/N₊),

wherein N_R is a number of minislots available for sending reservation requests of the second type in the selected frame, and

wherein N₊ is an estimated backlog of reservation requests of the second type pending at a beginning of the selected frame.

5. The multiple access communication protocol according to claim 1, wherein the feedback message includes slot assignment information for at least one frame following the selected frame.

6. The multiple access communication protocol according to claim 1, wherein the feedback message includes information relating to a number of minislots available in a frame after the selected frame for sending reservation requests of the second type, and information relating to an estimated backlog of reservation requests of the second type pending at a beginning of the frame after the selected frame.

7. The multiple access communication protocol according to claim 1, wherein the minislot contention information includes information relating to a successful sending of the reservation requests of the second type.

8. The multiple access communication protocol according to claim 1, wherein the information of the first type is a talkspurt of a voice message, and the information of the second type is a data message.

9. The multiple access communication protocol according to claim 1, wherein the information of the first type is transmitted in the uplink channel in a slot in a frame that is subsequent to the selected frame that is assigned in response to the reservation request of the first type.

10. The multiple access communication protocol according to claim 9, wherein an end indication message is sent in the slot in the frame that is subsequent to the selected frame that is assigned in response to the reservation request of the first type when transmission of the information of the talkspurt is ending.

11. The multiple access communication protocol according to claim 10, wherein the downlink channel contains a message having a minislot assignment in response to the end indication message.

12. The multiple access communication protocol according to claim 1, wherein the first selectable number of minislots and the second selectable number of slots are each predetermined.

13. The multiple access communication protocol according to claim 1, wherein the first selectable number of minislots and second selectable number of slots are each adjustable.

14. The multiple access communication protocol according to claim 1, wherein the uplink and downlink channels are part of a time division multiple access communication system.

15. The multiple access communication protocol according to claim 1, wherein the uplink and downlink channels are part of a frequency division multiple access communication system.

16. The multiple access communication protocol according to claim 1, wherein the uplink and downlink channels are part of a code division multiple access communication system.

17. The multiple access communication protocol according to claim 1, wherein the at least one slot assigned for transmitting information of the first type is assigned based on a contention-free reservation mechanism.

18. A method for providing multiple access to a communication channel, the method comprising steps of:

forming an uplink channel having a plurality of frames, each frame having a first selectable number of minislots and a second selectable number of slots;

receiving a reservation request of a first type contained in a first selected minislot of a selected frame of the uplink channel when information of a first type is ready to be sent, the reservation request of the first type requesting an assignment for at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame;

assigning at least one first slot in response to the received reservation request of the first type;

receiving a reservation request of a second type contained in a second selected minislot of the selected frame when the second selected minislot is available in the selected frame and when information of a second type is ready to be sent, the reservation request of the second type requesting an assignment for at least one slot for transmitting information of the second type in at least one frame that is subsequent to the selected frame, the reservation request of the second type contending for the second selected minislot based on a pseudo-Bayesian Aloha algorithm;

broadcasting a feedback message in a downlink channel before an end of the selected frame, the feedback message containing minislot assignment information for sending reservation requests of the first and the second type, slot assignment information for transmitting information of the first and the second type, minislot contention information for the reservation requests of the second type received in the selected frame, and reservation backlog information for an estimated number of reservation requests of the second type pending at a beginning of the selected frame.

19. The method according to claim 18, wherein the feedback message includes slot assignment information for at least one frame following the selected frame.

20. The method according to claim 18, wherein the feedback message includes information relating to a number of minislots available in a frame after the selected frame for sending reservation requests of the second type, and information relating to an estimated backlog of reservation requests of the second type pending at a beginning of the frme after the selected frame.

21. The method according to claim 18, wherein the minislot contention information includes information relating to successful receipt of the reservation requests of the second type.

22. The method according to claim 18, wherein the information of the first type is a talkspurt of a voice message, and the information of the second type is a data message.

23. The method according to claim 18, further comprising a step of receiving information of the first type in the uplink channel in a slot in a frame that is subsequent to the selected frame that was assigned in response to the reservation request of the second type.

24. The method according to claim 23, further comprising a step of receiving an end indication message in the slot in a frame that is subsequent to the selected frame that was assigned in response to the reservation request of the first type when transmission of the information of the first type is ending.

25. The method according to claim 24, further comprising a step of broadcasting a message having a minislot assignment in response to the end indication message.

26. The method according to claim 18, wherein the first selectable number of minislots and the second selectable number of slots are predetermined.

27. The method according to claim 18, wherein the first selectable number of minislots and the second selectable number of slots are adjustable.

28. The method according to claim 18, wherein the uplink and downlink channels are part of a time division multiple access communication system.

29. The method according to claim 18, wherein the uplink and downlink channels are part of a frequency division multiple access communication system.

30. The method according to claim 18, wherein the uplink and downlink channels are part of a code division multiple access communication system.

31. The method according to claim 18, wherein the at least one slot assigned for transmitting information of the first type is assigned based on a contention-free reservation mechanism.

32. A method for providing multiple access to a communication channel, the method comprising steps of

sending a reservation request of a first type into a first selected minislot of a selected frame of an uplink channel when information of a first type is to be sent, the uplink channel having a plurality of frames, each frame having a first selectable number of minislots and a second selectable number of slots the reservation request of the first type requesting an assignment for at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame,

sending a reservation request of a second type into a second selected minislot of the selected frame when the second selected minislot is available in the selected frame and when information of a second type is to be sent, the reservation request of the second type requesting an assignment of at least one slot for transmitting information of the second type in at least one frame that is subsequent to the selected frame, the reservation request of the second type contending for the second selected minislot based on a pseudo-Bayesian Aloha algorithm and

receiving a feedback message from a downlink channel, the feedback message containing minislot assignment information for sending reservation requests of the first and the second type, slot assignment information for transmitting information of the first and the second type, minislot contention information for the reservation requests of the second type sent in the selected frame, and reservation backlog information for an estimated number of reservation requests of the second type pending at a beginning of the selected frame, the feedback message being received prior to an end of the selected frame of the uplink channel.

33. The method according to claim 32, wherein the reservation requests of the second type are sent into the second selected minislots, each second selected minislot being selected independently and at random with equal probability from a plurality of minislots available for sending the reservation requests of the second type.

34. The method according to claim 32, wherein the reservation request message of the second type is sent into the second selected minislot with a probability that is based on a number of minislots available in the selected frame for sending reservation requests of the second type and on an estimated backlog of reservation requests of the second type pending at a beginning of the selected frame.

35. The method according to claim 34, wherein the probability is determined as:

p=min(1,N_R/N₊),

wherein N_R is a number of minislots available for sending reservation requests of the second type in the selected frame, and

wherein N₊ is an estimated backlog of messages of the second type pending at a beginning of the selected frame.

36. The method according to claim 34, wherein the feedback message includes slot assignment information for at least one frame following the selected frame.

37. The method according to claim 34, wherein the feedback message includes information relating to a number of minislots available in a frame after the selected frame for sending reservation requests of the second type, and information relating to an estimated backlog of reservation requests of the second type pending at a beginning of the frame after the selected frame.

38. The method according to claim 32, wherein the minislot contention information includes information relating to a successful sending of the reservation requests of the second type.

39. The method according to claim 32, wherein the information of the first type is a talkspurt of a voice message, and the information of the second type is a data message.

40. The method according to claim 32, wherein the information of the first type is transmitted in the uplink channel in a slot in a frame that is subsequent to the selected frame that is assigned in response to the reservation request of the first type.

41. The method according to claim 40 wherein an end indication message is sent in the slot in a frame that is subsequent to the selected frame that is assigned in response to the reservation request of the first type when transmission of the information of the talkspurt is ending.

42. The method according to claim 41, further comprising a step of receiving a message from the downlink channel containing a minislot assignment in response to the end indication message.

43. The method according to claim 32, wherein the first selectable number of minislots and the second selectable number of slots are each predetermined.

44. The method according to claim 32, wherein the first selectable number of minislots and second selectable number of slots are each adjustable.

45. The method according to claim 32, wherein the uplink and downlink channels are part of a time division multiple access communication system.

46. The method according to claim 32, wherein the uplink and downlink channels are part of a frequency division multiple access communication system.

47. The method according to claim 32, wherein the uplink and downlink channels are part of a code division multiple access communication system.

48. The method according to claim 32, wherein the at least one slot assigned for transmitting information of the first type is assigned based on a contention-free reservation mechanism.

49. A system for providing multiple access to a communication channel, the system comprising:

a central station; and

a plurality of terminal units coupled to the central station through a communication channel, the communication channel including an uplink channel having a plurality of frames, each frame having a first selectable number of minislots and a second selectable number of slots, a first terminal unit sending a reservation request of a first type into a first selected minislot of a selected frame when the first terminal has information of a first type to be sent to the central station, the reservation request of the first type requesting for an assignment of at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame, and a second terminal unit sending a reservation request of a second type for a slot assignment into a second selected minislot of the selected frame when the second minislot is available in the selected frame and when the second terminal has information of a second type to be sent to the central station, the reservation request of the second type requesting for an assignment of at least one slot for transmitting information of the second type in at least one frame that is subsequent to the selected frame, the second terminal unit contending for the second selected minislot based on a pseudo-Bayesian Aloha algorithm; and

the central station receiving the reservation request of the first type when the reservation request of the first type is sent into the first selected minislot and the reservation request of the second type when the reservation request of the second type is sent into the second selected minislot, and broadcasting a feedback message in a downlink channel prior to the end of the selected frame, the feedback message containing minislot assignment information for the first and the second terminal unit to send the reservation request of the first and the second type, slot assignment information for the first and the second terminal unit to send information of the first and the second type, minislot contention information for the reservation requests of the second type received by the central station, and reservation backlog information for an estimated number of reservation requests of the second type pending at a beginning of the selected frame,

the first terminal unit receiving the feedback message and transmitting the information of the first type based on the slot assignment information for the first terminal unit, and

the second terminal unit receiving the feedback message when the second terminal unit sends the reservation request of the second type into the second selected minislot, and determining from the minislot contention information whether the second terminal unit successfully contended for the second selected minislot.

50. The system according to claim 49, wherein the reservation requests of the second type are sent by the second terminal units into the second selected minislots, each second selected minislot being selected independently and at random with equal probability from a plurality of minislots available for the second terminal units to send reservation requests of the second type.

51. The system according to claim 50, wherein the second terminal unit sends the reservation request message of the second type into the second selected minislot with a probability that is based on a number of minislots available in the selected frame for sending reservation requests of the second type and on an estimated backlog of messages of the second type pending at a beginning of the selected frame.

52. The system according to claim 51, wherein the probability is determined as:

p=min(1,N_R/N₊),

wherein N_R is a number of minislots available for sending reservation requests of the second type in the selected frame, and

wherein N₊ is an estimated backlog of reservation requests of the second type pending at a beginning of the selected frame.

53. The system according to claim 49, wherein the feedback message includes slot assignment information for at least one frame following the selected frame.

54. The system according to claim 49, wherein the feedback message includes information relating to a number of minislots available in a frame after the selected frame for sending reservation requests of the second type, and information relating to an estimated backlog of reservation requests of the second type pending at a beginning of the frame after the selected frame.

55. The system according to claim 49, wherein the minislot contention information includes information relating to a successful sending of the reservation requests of the second type.

56. The system according to claim 49, wherein the information of the first type is a talkspurt of a voice message, and the information of the second type is a data message.

57. The system according to claim 49, wherein the first terminal unit sends the information of the first type in the uplink channel in at least one slot in at least one frame that is subsequent to the selected frame that was assigned in response to the reservation request of the first type.

58. The system according to claim 57, wherein the first terminal unit transmits an end indication message in a slot in a frame that is subsequent to the selected frame that was assigned in response to the reservation request of the first type when transmission of the information of the first type is ending.

59. The system according to claim 58, wherein the central station broadcasts a message having a minislot assignment in response to the end indication message.

60. The system according to claim 49, wherein the first selectable number of minislots and the second selectable number of slots are each predetermined.

61. The system according to claim 49, wherein the first selectable number of minislots and the second selectable number of slots are each adjustable.

62. The system according to claim 49, wherein the uplink and downlink channels are part of a time division multiple access communication system.

63. The system according to claim 49, wherein the uplink and downlink channels are part of a frequency division multiple access communication system.

64. The system according to claim 49, wherein the uplink and downlink channels are part of a code division multiple access communication system.

65. The system according to claim 49, wherein the at least one slot assigned for transmission of the information of the first type is assigned based on a contention-free reservation mechanism.