Access method, mobile station and base station for CDMA mobile communication system

• US 6,078,572 A
• Filed: 09/17/1996
• Issued: 06/20/2000
• Est. Priority Date: 09/20/1995
• Status: Expired due to Term

• Current Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Tanno, Motohiro, Uebayashi, Shinji
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US08/718,644
• Time in Patent Office: 1,372 Days
• Field of Search: 370/336, 370/337, 370/328, 370/347, 370/348, 370/329, 370/341, 370/468, 370/335, 370/441, 370/431, 370/344, 370/345, 370/442, 455/434, 455/515, 455/517
• US Class Current: 370/335
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements
• CPC Class Codes: H04W 36/0007 for multicast or broadcast services, e.g. MBMS multicast or broadcast application services H04W4/06; resource management for broadcast services H04W72/30; connection management for selective distribution or broadcast H04W76/40
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access
• CPC Class Codes: H04W 8/24 Transfer of terminal data

Abstract

In a CDMA mobile communication system, for realizing a multiple-access, a common reverse channel 10 is divided into an access channel 10A and a message channel 10B. When data (packet) to be transmitted occurs in any mobile station 1-4, mobile station having data to be transmitted transmits a transmission request signal including information, such as packet size or the like, by using the access channel 10A. In contrast, base station 30 transmits a transmission permission signal, which designates a transmission timing of data and a spreading code to be used as transmitting, on the basis of the state of utilization of message channel 10B and the state of occurrence of data. Mobile stations 1-4 transmits data in accordance with the spreading code and the transmission timing which are designated from base station 30.

Claims

1. A multiple-access method for communication between a base station and a plurality of mobile stations, said method comprising the steps of:

(a) establishing a common channel for transmitting data from said mobile stations to said base station, said common channel being defined with at least one access channel and at least one message channel;

(b) establishing a broadcast channel for transmitting data from said base station to said mobile stations;

(c) transmitting message data, if smaller than a certain size, from a mobile station to said base station through said access channel;

(d) requesting transmission of message data, if larger than said certain size, from a mobile station to said base station through said access channel, said request including information regarding the size of said larger message data to be transmitted;

(e) determining at said base station in response to said request a timing to transmit said larger message data, based on the size of said larger message data and a traffic condition on said message channel;

(f) advising said mobile station of said determined timing through said broadcast channel; and

(g) transmitting said larger message data at said determined timing from said mobile station to said base station through said message channel.

2. A multiple-access method according to claim 1, wherein said common channel is defined with a plurality of said message channels.

3. A multiple-access method according to claim 2, wherein

a different spread code is assigned to each of said message channels, at least one of said spread codes being allotted to each of said mobile stations,

said base station selects at least one spread code from those allotted to said mobile station and advises said mobile station of said selected spread code in addition to said determined timing to transmit said larger message data, and

said mobile station transmits said larger message data at said determined timing, using said selected spread code.

4. A multiple-access method according to claim 3, wherein said mobile station, upon requesting transmission of said larger message data, advises said base station, through said access channel, of the spread codes allotted thereto.

5. A multiple-access method according to claim 1, wherein said common channel is defined with a plurality of said access channels.

6. A multiple-access method according to claim 5, wherein at least one of said access channels is allotted to each of said mobile stations, and said mobile station requests, through said access channel allotted thereto, transmission of said larger message data.

7. A multiple-access method according to claim 5, wherein each of said mobile stations is assigned a different distribution of probabilities that a data collision will occur on said access channels, and said mobile station selects one of said access channels according to said probability distribution assigned thereto.

8. A multiple-access method according to claim 5, wherein said base station advises each of said mobile stations, through said broadcast channel, of said probability distribution assigned thereto.

9. A multiple-access method according to claim 1, further comprising the steps of:

(h) detecting a traffic condition on said access channel;

(i) determining, based on said detected traffic condition, a probability that one mobile station can transmit data through said access channel without a collision with other data from another mobile station;

(j) generating a random number at each of mobile stations that have data to be transmitted through said access channel;

(k) separating said mobile stations that have data to be transmitted into a first group and a second group according to whether their random numbers are larger or smaller than said probability;

(l) halting the mobile stations in said first group for a certain period of time and then moving back to said step (j); and

(m) allowing the mobile stations in said second group to transmit, through said access channel, either said smaller message data or said request to transmit said larger message data.

10. A multiple-access method according to claim 9, wherein said base station performs said steps (h) and (i) and notifies said mobile stations of said probability.

11. A multiple-access method according to claim 9, wherein said base station performs said step (h) and notifies said mobile stations of said detected traffic condition on said access channel, and said mobile stations perform said step (i).

12. A multiple-access method according to claim 10, wherein in said step (l), said steps (h) and (i) are executed.

13. A multiple-access method according to claim 11, wherein in said step (l), said steps (h) and (i) are executed.

14. A multiple-access method according to claim 10, wherein in said step (m), said steps (h) and (i) are executed.

15. A multiple-access method according to claim 10, wherein in said step (m), said steps (h) and (i) are executed.

16. A multiple-access method according to claim 9, each of said mobile stations can individually change said certain period of time for which it is to be halted.

17. A multiple-access method according to claim 16, wherein each of said mobile stations changes said certain period of time at random.

18. A multiple-access method according to claim 16, wherein each of said mobile stations changes said certain period of time on the basis of a number of times it has been halted.

19. A multiple-access method according to claim 9, wherein each of said mobile stations can individually adjust said probability on the basis of a number of times it has been halted.

20. A base station communicating with a plurality of mobile stations, said base station comprising:

(a) a receiver (31) for establishing a common channel with said mobile stations to receive data therefrom, said common channel being defined with at least one access channel and at least one message channel,

said access channel being used to receive message data of a size smaller than a certain value and a request for transmitting message data of a size larger than said certain value, said request including information regarding the size of said larger message data to be received, and

said message channel being used to receive said larger message data;

(b) A traffic controller (32) for determining in response to said request a timing to transmit said larger message data, based on the size of said larger message and a traffic condition on said message channel; and

(c) a transmitter (31) for establishing a broadcast channel with said mobile stations to advise said mobile station of said determined timing.

21. A base station according to claim 20, wherein said common channel is defined with a plurality of said message channels.

22. A base station according to claim 21, wherein

a different spread code is assigned to each of said message channels, at least one of said spread codes being allotted to each of said mobile stations,

said traffic controller selects at least one spread code among those allotted to said mobile station, and

said transmitter advises said mobile station, through said broadcast channel, of said selected spread code in addition to said determined timing to transmit said larger message data.

23. A base station according to claim 20, wherein said common channel is defined with a plurality of said access channels.

24. A base station according to claim 23, wherein said traffic controller assigns each of said mobile stations a different distribution of probabilities that a data collision will occur on said access channels, and said transmitter advises each of said mobile stations, through said broadcast channel, of said probability distribution assigned thereto.

25. A mobile station communicating with a base station, said mobile station comprising:

(a) a receiver (51) for establishing a broadcast channel with said base station to receive a timing to transmit message data of a size larger than a certain value; and

(b) a transmitter (51) for establishing a common channel with said base station to transmit data thereto, said common channel being defined with at least one access channel and at least one message channel,

said access channel being used to transmit message data of a size smaller than said certain value and a request for transmitting said larger message data, said request including information regarding the size of said larger message data to be transmitted, and

said message channel being used to transmit said larger message data at said timing received from said base station.

26. A mobile station according to claim 25, wherein said common channel is defined with a plurality of said message channels.

27. A mobile station according to claim 26, wherein

a different spread code is assigned to each of said message channels, at least one of said spread codes being allotted to said mobile station,

said request includes information regarding the spread codes allotted to said mobile station, and

said transmitter transmits said larger message data at said timing received from said base station, using at least one spread code selected by said base station from said spread codes allotted to said mobile station.

28. A mobile station according to claim 25, wherein said common channel is defined with a plurality of said access channels.

29. A mobile station according to claim 28, wherein at least one of said access channels is allotted to said mobile station, and said transmitter transmits, through said access channel allotted to said mobile station, said request for transmitting said larger message data.

30. A mobile station according to claim 28, wherein said mobile station is assigned a different distribution of probabilities that a data collision will occur on said access channels, and said mobile station further comprises a control portion (51) that selects one of said access channels according to said probability distribution assigned thereto.

31. A multiple-access method for a CDMA mobile communication system having a common channel through which a plurality of mobile stations transmit data to a base station and a broadcast channel through which said base station transmits data to said mobile stations, said common channel being defined with at least one access channel and at least one message channel, said multiple-access method comprising the steps of:

(a) detecting a traffic condition on said access channel;

(b) determining, based on said detected traffic condition, a probability that one mobile station can transmit data through said access channel without a collision with other data from another mobile station;

(c) generating a random number at each of mobile stations that have message data to be transmitted through said message channel;

(d) separating said mobile stations that have said message data to be transmitted into a first group and a second group according to whether their random numbers are larger or smaller than said probability;

(e) halting the mobile stations in said first group for a certain period of time and then moving back to said step (c);

(f) allowing the mobile stations in said second group to transmit, through said access channel, a request to transmit said message data;

(g) determining at said base station timings for the mobile stations in said second group to transmit their message data;

(h) advising the mobile stations in said second group of the determined timings through said broadcast channel; and

(i) transmitting said message data at said determined timings from the mobile stations in said second group to said base station through said message channel.

32. A multiple-access method according to claim 31, wherein said common channel is defined with a plurality of said message channels.

33. A multiple-access method according to claim 32, wherein

a different spread code is assigned to each of said message channels, at least one of said spread codes being allotted to each of said mobile stations,

said base station selects at least one spread code from those allotted to the mobile station and advises said mobile station of said selected spread code in addition to said determined timing to transmit said message data, and

said mobile station transmits said message data at said determined timing, using said selected spread code.

34. A multiple-access method according to claim 33, wherein said mobile station, upon requesting transmission of said message data, advises said base station through said access channel of the spread codes allotted thereto.

35. A multiple-access method according to claim 31, wherein said base station performs said steps (a) and (b) and notifies said mobile stations of said probability.

36. A multiple-access method according to claim 31, wherein said base station performs said step (a) and notifies said mobile stations of said detected traffic condition on said communication channel, and said mobile stations perform said step (b).

37. A multiple-access method according to claim 35 wherein in said step (e), said steps (a) and (b) are executed.

38. A multiple-access method according to claim 36, wherein in said step (e), said steps (a) and (b) are executed.

39. A multiple-access method according to claim 35, wherein in said step (f), said step (a) and (b) are executed.

40. A multiple-access method according to claim 36, wherein in said step (f), said steps (a) and (b) are executed.

41. A multiple-access method according to claim 31, each of said mobile stations can individually change said certain period of time for which it is to be halted.

42. A multiple-access method according to claim 41, wherein each of said mobile stations changes said certain period of time at random.

43. A multiple-access method according to claim 42, wherein each of said mobile stations changes said certain period of time on the basis of a number of times it has been halted.

44. A multiple-access method according to claim 31, wherein each of said mobile stations can individually adjust said probability on the basis of a number of times it has been halted.

45. A multiple-access method for controlling communication among a plurality of stations sharing at least one communication channel, said method comprising the steps of:

(a) detecting a traffic condition on said communication channel;

(b) determining, based on said detected traffic condition, a probability that one station can transmit data through said communication channel without a collision with other data from another station;

(c) generating a random number at each of stations that have data to be transmitted through said communication channel;

(d) separating said stations that have data to be transmitted into a first group and a second group according to whether their random numbers are larger or smaller than said probability;

(e) halting the stations in said first group for a certain period of time and then moving back to said step (c); and

(f) allowing the stations in said second group to transmit the data through said communication channel.

46. A multiple-access method according to claim 45, wherein in said step (e), said steps (a) and (b) are executed.

47. A multiple-access method according to claim 45, wherein in said step (f), said step (a) and (b) are executed.

48. A multiple-access method according to claim 45, each of said stations can individually change said certain period of time for which it is to be halted.

49. A multiple-access method according to claim 48, wherein each of said stations changes said certain period of time at random.

50. A multiple-access method according to claim 48, wherein each of said stations changes said certain period of time on the basis of a number of times it has been halted.

51. A multiple-access method according to claim 45, wherein each of said stations can individually adjust said probability on the basis of a number of times it has been halted.