Mobile communication system, communication control method, and base station and mobile station to be employed in the same

Abstract

In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.

1 . A communication control method, comprising:
 compressing communication data, in a stream of communication data from a base station to a mobile station, in a time direction, thereby providing a vacant period, in which no communication data is present, in a data transmission from a base station to a mobile station;   inserting a transmission power control signal into the vacant period, such that both a beginning of the transmission power control signal and an end of the transmission power control signal are contiguous with a period in which no communication data is present; and   performing inter-frequency measurement during the vacant period.   
     
     
         2 . The communication control method according to  claim 1 , further comprising:
 receiving the data transmission from the base station at the mobile station;   extracting the transmission power control signal from the received data trans mission;   controlling a transmission power of a signal from the mobile station to the base station based on the extracted transmission power control signal;   wherein the base station and the mobile station operate according to a Code Division Multiple Access (CDMA) system.   
     
     
         3 . A communication control method, comprising:
 compressing communication data, in a stream of communication data from a base station to a mobile station, in a time direction, thereby providing a vacant period, in which no communication data is present, in a data transmission from a base station to a mobile station;   inserting a transmission power control signal into the vacant period, such that both a beginning of the transmission power control signal and an end of the transmission power control signal are contiguous with a period in which no communication data is present;   receiving the data transmission from the base station at the mobile station;   extracting the transmission power control signal from the received data transmission;   controlling a transmission power of a signal from the mobile to the base stat ion based on the extracted transmission power control signal;   performing inter-frequency measurement during the vacant period; and before providing the vacant period,   transmitting a notification signal from the mobile station to the base station based on a detection of a degradation in reception quality; and   switching from a normal communication mode to a transmission mode having a vacant period based on the transmitted notification signal;   wherein the base station and mobile station operate according to Code Division Multiple Access (CDMA) system.   
     
     
         4 . A communication control system, comprising: a base station, comprising:
 a first circuit which compresses communication data, in a time direction, and thereby provides a vacant period, in which no communication data is present, in a data transmission from a base station to a mobile station, and   a second circuit which inserts a transmission power control signal into the vacant period, such that both a beginning of the transmission power control signal and an end of the transmission power control signal are contiguous with a period in which no communication data is present; and   a mobile station comprising:   a circuit which performs inter-frequency measurement during the vacant period.   
     
     
         5 . The communication control system according to  claim 4 , further comprising:
 a transmission and reception circuit which receives data transmissions from the base station;   a transmission power control signal extracting portion which extracts the transmission power control signal from the received data transmission having the vacant period; and   a power amplifier which controls a transmission power of a signal from the mobile station to the base station based on the extracted transmission power control signal.   
     
     
         6 . A mobile station in a mobile communication system, comprising:
 a transmission and reception circuit which receives data transmissions from a base station;   wherein at least one of the received data transmission includes: a vacant period in which no communication data is present, and   a transmission power control signal inserted into the vacant period, such that both a beginning of the transmission power control signal and an end of the transmission power control signal are contiguous with a period in which no communication data is present; and   a circuit which performs inter-frequency measurement during the vacant period;   wherein communication data in the data transmission from the base station is compressed in a time direction and thereby, the vacant period is provides.   
     
     
         7 . The mobile station according to  claim 6 , further comprising:
 a transmission power control signal extracting portion which extracts the transmission power control signal from the received data transmission having the vacant period; and   a power amplifier which controls a transmission power of a signal from the mobile station to the base station based on the extracted transmission power control signal;   wherein the mobile station operates according to a Code Division Multiple Access (CDMA) system.   
     
     
         8 . A mobile station in a mobile communication system, comprising:
 a transmission and reception circuit which receives data transmissions from a base station;   wherein at least one of the received data transmissions includes: a vacant period in which no communication data is present, and   a transmission power control signal inserted into the vacant period, Such that both beginning of the transmission power control signal and an end of the transmission power control signal are contiguous with a period in which no communication data is present;   a transmission power control signal extracting portion which extracts the transmission power control signal from the received data transmission having the vacant period;   a power amplifier which controls a transmission power of a signal from the mobile station to the base station based on the extracted transmission power control signal;   a circuit which performs inter-frequency measurement during the vacant period   an SIR measuring portion which measures a reception quality of a received data transmission from the base station; and   a notification circuit which, upon a detection of a degradation in reception quality, transmits a notification Signal to the base station to switch from a normal communication mode to a transmission mode having a vacant period;   wherein communication data in the data transmission from the base station is compressed in a time direction and thereby, the vacant period is provided; and   wherein the mobile station operates according to a Code Divisional Multiple Access (CDMA) system.   
     
     
         9 . A control method of a mobile station in a mobile communication system, comprising:
 receiving data transmission from a base station, wherein at least one of the received data transmissions includes:   a vacant period in which no communication data is present, and   a transmission power control signal inserted into the vacant period, such that both a beginning of the transmission power control signal and an end of the   transmission power control signal are contiguous with a period in which no communication data is present;   extracting the transmission power control signal from the received data trans mission having the vacant period;   increasing or decreasing transmission power of the mobile station based on the extracted transmission power control signal; and   performing inter-frequency measurement during the vacant period;   wherein communication data in the data transmission from the base station is compressed in a time direction, and thereby the vacant period is provided; an d   wherein the mobile station operates according to a Code Division Multiple Access (CDMA) system.   
     
     
         10 . A communication control system, comprising: a base station, comprising:
 means for compressing communication data, in a stream of communication data from the base station to a mobile station, in a time direction, thereby providing a vacant period, in which no communication data is present, in a data transmission from the base station to a mobile station, and   means for inserting a transmission power control signal into the vacant period, such that both a beginning of the transmission power control signal an end of the transmission power control signal are contiguous with a period in which no communication data is present; and   a mobile station comprising:   means for performing inter-frequency measurement during the vacant period.   
     
     
         11 . The communication control system according to  claim 10 , wherein the mobile station further comprises:
 means for extracting the transmission power control signal from the received data transmission having the vacant period;   means for controlling a transmission power of a signal from the mobile station n to the base station on the extracted transmission power control signal; and   wherein the communication control system is a Code Division Multiple Access (CDMA) system.