Base station transmission power control system, mobile station and base station

• US 20020193115A1
• Filed: 08/06/2002
• Published: 12/19/2002
• Est. Priority Date: 02/16/1998
• Status: Active Grant

• Current Assignee: Hiroshi Furukawa, Kojiro Hamabe, Shousei Yoshida
• Original Assignee: Hiroshi Furukawa, Kojiro Hamabe, Shousei Yoshida
• Inventors: Hamabe, Kojiro, Furukawa, Hiroshi, Yoshida, Shousei
• Granted Patent: US 7,035,641 B2
• Time in Patent Office: Days
• US Class Current: 455/442
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• 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 52/143 Downlink power control
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/248 where transmission power control commands are generated based on a path parameter
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

In soft hand over in a code division multi access mobile radio communication system, interference in a down link caused by transmission from a plurality of base stations for one mobile station, can be restricted. Control of transmission power is performed according to command from the mobile station only in the base station serving as a primary base station which has minimum propagation loss with the mobile station during soft hand over, and the base stations other than the primary base station perform transmission with restricting output. In comparison with the transmission power control performed by the conventional plural base station transmission, interference for the peripheral mobile station can be reduced to achieve higher down link capacity. Also, upon restricting transmission power of the base station other than the base stations having small propagation loss with the mobile station among base station group in soft hand over, by moderately attenuating the transmission power instead of restricting abruptly, degradation of the reception quality can be prevented when error is caused in selection of the base station.

Claims

1. A base station transmission power control system in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, wherein said soft hand over base station group including a primary base station having minimum propagation loss with said mobile station during soft hand over and remaining base stations being restricted outputs.

2. A base station transmission power control system as set forth in claim 1, wherein said primary base station performs control of a transmission power according to a command from said mobile station.

3. A base station transmission power control system as set forth in claim 2, wherein said mobile station takes one of base stations of said soft hand over base station group, in which a reception level of received pilot signal is maximum, as said primary base station, and controls the transmission power of said primary base station for achieving a desired communication reception quality.

4. A base station transmission power control system in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, wherein

said mobile station detecting a communication reception quality and a primary base station among said base stations, reception level of pilot signal of which becomes maximum among pilot signals received from respective base stations in said soft hand over base station group, notifying a base station number of said primary base station as a transmission power control signal for respective of said base stations in said soft hand over base station group when said communication reception quality is lower than a desired quality, and notifying a number other than the base station number of the base stations in said soft hand over base station group when said communication reception quality is in excess of said desired quality;

and

each base station in said soft hand over base station group receiving said transmission power control signal and being restricted a transmission power when a content of said transmission power control signal identifies number other than own base station number.

5. A base station transmission power control system as set forth in claim 4, wherein each base station in said soft hand over base station group manages two transmission power values including a first transmission power value and a second transmission power value, decreases said first transmission power value when the content of said transmission power control signal identifies number other than said base station number in said soft hand over base station group, increases said first transmission power value when the content of said transmission power control signal identifies any one of said base station number in said soft hand over base station group, selectively sets one of said first transmission power value and a minimum transmission power value as said second transmission power value, sets said first transmission power value as said second transmission power value when the content of said transmission power control signal identifies own base station number, sets said minimum transmission power value as said second transmission power value when the content of said transmission power control signal identifies said base station number in said soft hand over base station group other than own base station number, sets said first transmission power value as said second transmission power value when the content of said transmission power control signal identifies other than base station number in said soft hand over base station group and when said first transmission power value is set as said second transmission power value in the preceding time, sets said minimum power value as said second transmission power value when the content of said transmission power control signal identifies base station number other than the base station number in said soft hand over base station group and said minimum transmission power value is set as said second transmission power value in the preceding time, and takes said second transmission power value as an output value of a transmission amplifier device.

6. A base station transmission power control system as set forth in claim 4, wherein each base station of said soft hand over base station group increases the transmission power when said transmission power control signal expresses the base station number of own base station and decreases said transmission power when said transmission power control signal doe not express the base station number of own base station.

7. A base station transmission power control system in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, wherein

said mobile station detecting a communication reception quality and a primary base station among said base stations, reception level of pilot signal of which becomes maximum among pilot signals received from respective base stations in said soft hand over base station group, increasing and decreasing the base station transmission power value managed by said mobile station so that said communication reception quality becomes a desired quality, and transmitting a transmission power control signal consisted of a base station number of said primary base station and said base station transmission power value to said soft hand over base station group, and

each base station of said soft hand over base station group receiving said transmission power control signal, setting said base station transmission power value managed by said mobile station and contained in said transmission power control signal to a transmission power value of own station when said base station number contained in said transmission power control signal is consistent with own base station number, and sets the transmission power value of own station at a restricted transmission power value when said base station number contained in said transmission power control signal is not consistent with own base station number.

8. A base station transmission power control system as set forth in claim 7, wherein said mobile station increases or decreases said base station transmission power in a magnitude corresponding to a difference between said communication reception quality and said desired quality.

9. A base station transmission power control system as set forth in claim 7, wherein said mobile station compares said communication reception quality and said desired quality for decreasing said base station transmission power value managed by said mobile station when said communication reception quality exceeds said desired quality and increasing said base station transmission power value managed by said mobile station when said communication reception quality does not exceed said desired quality.

10. A base station transmission power control system in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, wherein

said mobile station detecting a communication reception quality and a primary base station among said base stations, reception level of pilot signal of which becomes maximum among pilot signals received from respective base stations in said soft hand over base station group, setting a power increasing symbol in a transmission power control bit when said communication reception quality does not exceed said desired quality, setting a power decreasing symbol in the transmission power control bit when said communication reception quality exceeds said desired quality, and transmitting said transmission power control bit to said soft hand over base station group and intermittently transmitting said primary base station number, and

each base station of said soft hand over base station group receiving said transmission power control signal which includes a primary base station number, and restricting a transmission power of one station following to the current timing when said primary base station number is not consistent with own base station number.

11. A base station transmission power control system as set forth in claim 10, wherein said mobile station transmits said transmission power control signal consisted of said primary base station number and said transmission power control bit to said soft hand over base station group only when variation is caused in said primary base station determined by said maximum pilot reception level, and transmits said transmission power control signal consisted of only transmission power control bit when variation of said primary base station is not caused.

12. A base station transmission power control system as set forth in claim 10, wherein said mobile station transmits the transmission power control signal consisted of only transmission power control bit to said soft hand over base station group and regularly transmits the transmission power control signal consisted of said primary base station number and said transmission power control bit to said soft hand over base station group.

13. A base station transmission power control system as set forth in claim 10, wherein each base station in said soft hand over base station group manages two transmission power values including a first transmission power value and a second transmission power value, increases and decreases said first transmission power value according to said transmission power control bit contained in said transmission power control signal, sets said first transmission power value as said second transmission power value for current and subsequent timing when the primary base station number is contained in said transmission power control signal and said primary base station number is consistent with own base station number, sets a minimum transmission power as said second transmission power value for current and subsequent timing when said primary base station number is contained in said transmission power control signal and said primary base station number is not consistent with own base station number, and sets said second transmission power value as an output value of a transmission amplifier device.

14. A base station transmission power control system as set forth in claim 10, wherein each base station of said soft hand over base station group increases and decreases transmission power for current and subsequent timing according to said transmission power control bit contained in said transmission power control signal when said primary base station number is contained in said transmission power control signal and said primary base station number is consistent with own base station number and decreases said transmission power irrespective of said transmission power control bit for current and subsequent timing when the primary base station number is contained in said transmission power control signal and said primary base station number is not consistent with own base station number.

16. A base station transmission power control system as set forth in claim 15, wherein each base station in said soft hand over base station group manages two transmission power values including a first transmission power value and a second transmission power value, increases and decreases said first transmission power value according to said transmission power control bit contained in said transmission power control signal, sets said first transmission power value as said second transmission power value for current and subsequent timing when the primary base station number is contained in said transmission power control signal and said primary base station number is consistent with own base station number, sets a minimum transmission power as said second transmission power value for current and subsequent timing when said primary base station number is contained in said transmission power control signal and said primary base station number is not consistent with own base station number, and sets said second transmission power value as an output value of a transmission amplifier device.

17. A base station transmission power control system as set forth in claim 15, wherein each base station of said soft hand over base station group increases and decreases transmission power for current and subsequent timing according to said transmission power control bit contained in said transmission power control signal when said primary base station number is contained in said transmission power control signal and said primary base station number is consistent with own base station number and decreases said transmission power irrespective of said transmission power control bit for current and subsequent timing when the primary base station number is contained in said transmission power control signal and said primary base station number is not consistent with own base station number.

19. A mobile station as set forth in claim 18, wherein said primary base station determining means comprises reception quality detecting means for detecting a reception quality, and primary base station detecting means for detecting said primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group, and said commanding means comprises control signal transmitting means for transmitting a transmission power control signal for said soft hand over base station group on the basis of results of detection by said reception quality detecting means and said primary base station detecting means.

20. A mobile station as set forth in claim 19, wherein said commanding means includes transmission power determining means for determining a primary base station information detected by said primary base station detecting means as said transmission power control signal when communication reception quality detected by said primary base station detecting means does not exceed a predetermined quality and determining a base station transmission power decreasing information as said transmission power control signal when communication reception quality detected by said primary base station detecting means exceeds said predetermined quality.

15. A base station transmission power control system in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, wherein

said mobile station detecting a communication reception quality and a primary base station among said base stations, reception level of pilot signal of which becomes maximum among pilot signals received from respective base stations in said soft hand over base station group, setting a power increasing symbol in a transmission power control bit when said communication reception quality does not exceed said desired quality, setting a power decreasing symbol in the transmission power control bit when said communication reception quality exceeds said desired quality, transmits a transmission power control signal consisted of said transmission power control bit or a transmission power control signal consisted of said primary base station number to said soft hand over base station, and

each base station in said soft hand over base station group receiving said transmission power control signal, and restricting a transmission power of own station for current and subsequent timing when said primary base station number is not consistent with own base station number.

18. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, comprising:

primary base station determining means for determining a primary base station having a minimum propagation loss during soft hand over; and

commanding means for commanding restriction of a transmission power for the base stations in said soft hand over base station group other than said primary base station.

21. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, comprising:

means for detecting a primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group, and

means for transmitting a transmission power control signal consisted of the base station number of said primary base station and said base station transmission power value by increasing and decreasing said base station transmission power value managed by said mobile station so that said reception quality becomes a desired quality.

22. A base station in a code division multi access cellular mobile ratio communication system announcing a unique pilot signal and is capable of simultaneously establishing connection with a mobile station together with other base stations in a soft hand over base station group consisted of some of base stations, comprising:

transmission power control signal detecting means for detecting a transmission power control signal from said mobile station; and

transmission power control means for restricting a transmission power when a primary base station information in said transmission power control signal does not identify own station.

23. A base station as set forth in claim 22, wherein said transmission power control signal detecting means comprises control signal detecting means for detecting said primary base station information or a base station transmission power decreasing information in said transmission power control signal, and said transmission power control means comprises means for restricting the transmission power when said primary base station information detected by said control signal detecting means does not identify own station.

24. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, comprising:

reception quality detecting means for detecting a communication reception quality;

primary base station detecting means for detecting primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group;

base station transmission power managing means for holding a base station transmission power value, increasing said base station transmission power value when the communication reception quality detected by said reception quality detecting means does not exceed a desired quality and decreasing said base station transmission power value when said communication reception quality detected by said reception quality detecting means exceeds said desired quality; and

control signal transmitting means for transmitting said primary base station information detected by said primary base station detecting means and said base station transmission power value held in said base station transmission power managing means as a transmission power control signal to said soft hand over base station group.

25. A base station in a code division multi access cellular mobile radio communication system announcing a unique pilot signal and is capable of simultaneously establishing connection with a mobile station together with other base stations in a soft hand over base station group consisted of some of base stations, comprising:

control signal receiving means for receiving a transmission power control signal from said mobile station;

control signal separating means for separating a primary base station information and a base station transmission power value information from said transmission power control signal; and

transmission power control means for performing transmission with the base station transmission power indicated by said base station transmission power value information when said primary base station information separated by said control signal separating means indicates a base station information of own station, and performing transmission with a minimum transmission power when said primary base station information detected by said control signal separating means does not indicate the base station information of own station.

26. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, comprising:

reception quality detecting means for detecting a communication reception quality;

primary base station detecting means for detecting primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group;

base station transmission power control signal determining means for setting a base station transmission power control signal for increasing power when said communication reception quality detected by said reception quality detecting means does not exceed a desired quality and setting said base station transmission power control signal for decreasing power when said communication reception quality detected by said reception quality detecting means exceeds a desired quality; and

control signal transmitting means for transmitting said base station transmission power control signal determined by said base station control signal determining means to the base station group in soft hand over or intermittently transmitting a primary base station information detected by said primary base station detecting means and said base station transmission power control signal determined by said base station control signal determining means to said base station group in soft hand over.

27. A base station in a code division multi access cellular mobile ratio communication system announcing a unique pilot signal and is capable of simultaneously establishing connection with a mobile station together with other base stations in a soft hand over base station group consisted of some of base stations, comprising:

control signal receiving means for receiving a transmission power control signal from said mobile station;

primary base station information separating means for separating a primary base station information and a base station transmission power value information from said transmission power control signal; and

transmission power control means for increasing and decreasing a transmission power for current and subsequent timing according to said transmission power control signal when said primary base station information is contained in said transmission power control signal and said primary base station information indicates the base station information of own station and setting the transmission power to a minimum transmission power for current and subsequent timing when said primary base station information is contained in said transmission power control signal and said primary base station information does not indicate the base station information of own station.

28. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, comprising:

reception quality detecting means for detecting a communication reception quality;

primary base station detecting means for detecting primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group;

base station transmission power control signal determining means for setting a base station transmission power control signal for increasing power when said communication reception quality detected by said reception quality detecting means does not exceed a desired quality and setting said base station transmission power control signal for decreasing power when said communication reception quality detected by said reception quality detecting means exceeds a desired quality; and

control signal transmitting means for transmitting said base station transmission power control signal determined by said base station control signal determining means to the base station group in soft hand over or regularly transmitting a primary base station information detected by said primary base station detecting means as said transmission power control signal to said base station group in soft hand over.

29. A base station in a code division multi access cellular mobile ratio communication system announcing a unique pilot signal and is capable of simultaneously establishing connection with a mobile station together with other base stations in a soft hand over base station group consisted of some of base stations, comprising:

control signal receiving means for receiving a transmission power control signal from said mobile station; and

transmission power control means for increasing and decreasing a transmission power for current and subsequent timing according to said transmission power control signal when a primary base station information is contained in said transmission power control signal and said primary base station information indicates the base station information of own station and setting the transmission power to a minimum transmission power for current and subsequent timing when said primary base station information is contained in said transmission power control signal and said primary base station information does not indicate the base station information of own station.

30. A mobile communication system comprising:

a mobile station; and

a plurality of base stations adapted for communication with said mobile station, one or more base stations having propagation loss in communication with said mobile station smaller than a predetermined threshold value during soft hand over being selected as communication stations, transmission power of a base station group of said base stations other than those selected as said communication stations being controlled for sequentially attenuating toward a predetermined minimum power with a given attenuation amount.

31. A mobile communication system as set forth in claim 30, wherein the transmission power of said base station group other than those selected as said communication stations is restricted.

32. A mobile communication system as set forth in claim 30 wherein the transmission power of one or more base stations those selected as said communication stations is controlled so that a combined reception quality in said mobile station becomes said given quality.

33. A cellular mobile communication system including a plurality of base stations and mobile station, comprising:

base station number assigning means for temporarily assigning base station numbers for a plurality of base stations in soft hand over with said mobile station;

base station selecting means for selecting the base station which transmits a pilot signal received by said mobile station at a maximum reception intensity among pilot signals transmitted from said base station in soft hand over;

transmission power control signal transmitting means for using a base station number of the selected base station as a transmission power control signal to be transmitted to said base station group in soft hand over from said mobile station; and

transmission power control means for controlling the transmission power of said base station on the basis of said transmission power control signal,

the transmission power of the base station other than the selected base station being controlled for sequentially attenuating toward a predetermined minimum power with a given attenuation amount.

34. A cellular mobile communication system as set forth in claim 33, wherein said base station number assigning means includes means for measuring a propagation loss between each base station and said mobile station during soft hand over, and assigns equal base station number for one or more base stations having propagation loss smaller than a predetermined threshold value.

35. A cellular mobile communication system as set forth in claim 33, wherein said base station number assigning means assigns mutually distinct base station number for respective base stations during soft hand over.

36. A cellular mobile communication system as set forth in claim 34, wherein said base station number assigning means performs re-assignment of said base station number when a set of base stations in soft hand over is varied.

37. A cellular mobile communication system as set forth in claim 34, wherein said base station number assigning means performs re-assignment of said base station number when a set of base stations in soft hand over is varied or when variation is caused in large and small of propagation loss with said mobile station, respectively.

38. A cellular mobile communication system as set forth in claim 33, wherein said base station selecting means performs selection of the base station using a combined value of reception intensity of said pilot signals when equal base station number is assigned for a plurality of base stations.

39. A cellular mobile communication system as set forth in claim 33, wherein said transmission power control signal transmitting means transmits a dedicated number commanding power reduction when communication reception quality in said mobile station exceeds a predetermined quality and transmits the base station number of base station selected by said base station selecting means in order to command increasing of power when the communication reception quality in said mobile station does not exceed said predetermined quality.

40. A cellular mobile communication system as set forth in claim 33, wherein said transmission power control means controls the transmission power of the base station selected by said base station selecting means so that the communication reception quality in said mobile station satisfies said predetermined quality.

41. A cellular mobile communication system as set forth in claim 33, wherein said transmission power control means restricts transmission power of the base station not selected by said base station selecting means.

42. A cellular mobile communication system as set forth in claim 33, wherein said transmission power control means includes virtual power management means for managing a virtual transmission power value premised for the case where the base station is constantly selected irrespective of selection of said base station and transmission power determining means for using said virtual transmission power value as said transmission power value of the base station.

43. A cellular mobile communication system as set forth inn claim 42, wherein said virtual power management means increases the transmission power when said base station number transmitted by said transmission power control signal transmitting means is the base station number of any of the base station in soft hand over and decreases otherwise.

44. A cellular mobile communication system as set forth in claim 33, wherein said base station number assignment means, said base station selecting means and said transmission power control signal transmitting means are provided in said mobile station and said transmission power control means is provided in said base station.

46. A communication control method as set forth in claim 45, wherein said base station number assigning step includes step of measuring a propagation loss between each base station and said mobile station during soft hand over, and assigns equal base station number for one or more base stations having propagation loss smaller than a predetermined threshold value.

47. A communication control method as set forth in claim 45, wherein said base station number assigning step assigns mutually distinct base station number for respective base stations during soft hand over.

48. A communication control method as set forth in claim 46, wherein said base station number assigning step performs re-assignment of said base station number when a set of base stations in soft hand over is varied.

49. A communication control method as set forth in claim 46, wherein said base station number assigning step performs re-assignment of said base station number when a set of base stations in soft hand over is varied or when variation is caused in large and small of propagation loss with said mobile station, respectively.

50. A communication control method as set forth in claim 45, wherein said base station selecting step performs selection of the base station using a combined value of reception intensity of said pilot signals when equal base station number is assigned for a plurality of base stations.

51. A communication control method as set forth in claim 45, wherein said transmission power control signal transmitting step transmits a dedicated number commanding power reduction when communication reception quality in said mobile station exceeds a predetermined quality, and transmits the base station number of base station selected by said base station selecting step in order to command increasing of power when the communication reception quality in said mobile station does not exceed said predetermined quality.

52. A communication control method as set forth in claim 45, wherein said transmission power control step controls the transmission power of the base station selected by said base station selecting step so that the communication reception quality in said mobile station satisfies said predetermined quality.

53. A cellular mobile communication system as set forth in claim 45, wherein said transmission power control step restricts transmission power of the base station not selected by said base station selecting step.

54. A cellular mobile communication system as set forth in claim 45, wherein said transmission power control step includes virtual power management step for managing a virtual transmission power value premised for the case where the base station is constantly selected irrespective of selection of said base station and transmission power determining step for using said virtual transmission power value as said transmission power value of the base station.

55. A cellular mobile communication system as set forth inn claim 54, wherein said virtual power management step increases the transmission power when said base station number transmitted by said transmission power control signal transmitting step is the base station number of any of the base station in soft hand over and decreases otherwise.

57. A mobile station as set forth in claim 56, wherein said primary base station determining means includes base station number assigning means for temporarily assigning base station numbers for base stations in soft hand over and base station selecting means for selecting base station which transmits a pilot signal received by said mobile station at a maximum reception intensity among pilot signals transmitted from said base station in soft hand over, and said transmitting means includes transmission power control signal transmitting means for transmitting the transmission power control signal for sequentially controlling attenuation of the transmission power with a given attenuation amount for the base station group in soft hand over.

58. A mobile station as set forth in claim 57, wherein said base station number assigning means assigns equal base station number for one or more base stations in which the propagation loss is smaller than a predetermined threshold value.

59. A mobile station as set forth in claim 57, wherein said base station number assigning means assigns mutually distinct base station numbers for respective base stations in soft hand over.

60. A mobile station as set forth in claim 57, wherein said base station number assigning means performs re-assignment of said base station number when a set of the base stations in soft hand over.

61. A mobile station as set forth in claim 57, wherein said base station number assigning means performs re-assignment of said base station number whew set of base stations in soft hand over is varied or when large and small relationship of propagation loss with respective bases station number is varied.

62. A mobile station as set forth in claim 57, wherein said base station selecting means performs selection of the base station using combined value of reception intensities of said pilot signals when equal base station number is assigned to a plurality of base stations.

63. A mobile station as set forth in claim 57, wherein said transmission power control signal transmitting means transmits a dedicated number as the transmission power control signal for commanding reduction of power when the communication reception quality is in excess of a predetermined quality and transmits the base station numbers of the base stations selected by said base station selecting means for commanding increasing power when the communication reception quality is not in excess of said predetermined quality.

45. A communication control method in a cellular mobile communication system including a plurality of base stations and mobile station, comprising:

base station number assigning step of temporarily assigning base station numbers for a plurality of base stations in soft hand over with said mobile station;

base station selecting step of selecting the base station which transmits a pilot signal received by said mobile station at a maximum reception intensity among pilot signals transmitted from said base station in soft hand over;

transmission power control signal transmitting step of using a base station number of the selected base station as a transmission power control signal to be transmitted to said base station group in soft hand over from said mobile station; and

transmission power control step of controlling the transmission power of said base station on the basis of said transmission power control signal,

the transmission power of the base station other than the selected base station being controlled for sequentially attenuating toward a predetermined minimum power with a given attenuation amount.

56. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals and capable of simultaneously establishing connection with a soft hand over base station group consisted of some of base stations out of said base stations in the system, comprising:

primary base station determining means for determining a primary base station having a minimum propagation loss during soft hand over; and

transmitting means for sequentially commanding attenuation control of transmission power for the base stations in said soft hand over base station group other than said primary base station, with a given attenuation amount.

64. A base station in a cellular mobile communication system temporarily assigned the base station number by a mobile station in soft hand over with said mobile station, comprising:

means for transmitting a pilot signal;

judgment means for receiving a transmission power control signal including a base station number selected as base station which transmits a pilot signal received by said mobile station at a maximum reception intensity among pilot signals transmitted from said base station in soft hand over and making judgment whether said base station number is consistent with a number assigned to own station or not; and

transmission power control means for performing sequential attenuation control of the transmission power with a given attenuation amount when said base station number and said number of own station are inconsistent with each other.

65. A base station as set forth in claim 64, wherein said transmission power control means controls the transmission power so that communication reception quality in said mobile station satisfies a predetermined quality when said judgment means makes judgment that said base station number is consistent with the number of own station.

66. A base station as set forth in claim 64, wherein said transmission power control means restricts transmission power when said base station number and the number of own station are inconsistent.

67. A base station as set forth in claim 64, wherein said transmission power control means includes virtual power managing means for managing a virtual transmission power value in consideration of the case where the base station is constantly selected irrespective of judgment made by said judgment means and transmission power determining means for using said virtual transmission power value as the transmission power value of the relevant base station when a certain base station is selected.

68. A base station as set forth in claim 67, wherein said virtual power management means increases the transmission power when said base station number is any one of the base station number in soft hand over, and decreases otherwise.