Abstract: By detecting a degraded state of wireless transmission quality due to steady occurrence of re-transmission in an early stage to lead to a call connection, a service quality is made sure, an excess time charge on an end user is prevented and wireless resources are utilized efficiently. A base station controller monitors a PDU transmission state in a wireless link to a mobile station in call unit, calculates an occurrence rate of re-transmission as an evaluation value of wireless transmission quality, determines a degradation of the wireless transmission quality when the occurrence rate of re-transmission becomes equal to or larger than a predetermined threshold value and performs a disconnection processing for the call.

Abstract: The telecommunication system has mobile telecommunication systems located with their coverage service areas overlapped with each other. Each of the mobile telecommunication systems provides a communication service to a mobile telephone terminal through a radio base station and a radio base station control unit. The radio base station control unit controls communication processing of the radio base station and the mobile telephone terminal. The radio base station control unit has a first means for providing a hard-handoff command signal to command the mobile telephone terminal to execute a hard handoff when the mobile telephone terminal is in the overlapped service area. The hard-handoff command signal is prescribed to become effective at a predetermined time after the mobile telephone terminal receives the hard-handoff command signal.

Abstract: By detecting a degraded state of wireless transmission quality due to steady occurrence of re-transmission in an early stage to lead to a call connection, a service quality is made sure, an excess time charge on an end user is prevented and wireless resources are utilized efficiently. A base station controller monitors a PDU transmission state in a wireless link to a mobile station in call unit, calculates an occurrence rate of re-transmission as an evaluation value of wireless transmission quality, determines a degradation of the wireless transmission quality when the occurrence rate of re-transmission becomes equal to or larger than a predetermined threshold value and performs a disconnection processing for the call.

Abstract: A mobile communication system, which is capable of improving a hand-off success rate of a mobile terminal moving in a high speed, and also capable of improving a process capability of a base station during hand-off control operation, is realized. When the mobile terminal, which has moved from one cell to another cell during communication, receives a hand-off instruction signal from a hand-off control unit of a mobile switching center, an electric field level measurement stopping unit stops the electric field level measurement of the forward control channels of the adjoining base stations which has instructed from the original hand-off base station, and also stops the transmission of the electric field level measurement result signal.

Abstract: Disclosed is a speech channel switching system which has: a radio base station control unit that allows a mobile telephone terminal to have a communication channel through a plurality of radio base station devices; and a radio base station which is provided with a field strength measurement-only channel which allows the mobile telephone terminal to measure the field strength of radiowave received. In the system, the mobile telephone terminal measures the field strength in field strength measurement-only channel designated and informing the radio base station control unit of the measurement results through the radio base station.

Abstract: If the present voice channel activity ratio (.alpha.) of a first radio base station used as an original radio base station is smaller than a threshold (.DELTA.CH) and the present voice channel activity ratio (.beta.) of a second radio base station used as a destination radio base station is equal to or greater than the threshold (.DELTA.CH), a predetermined threshold (.DELTA.AB) for determining the difference between the levels (Ra) and (Rb) of electric fields received from a mobile terminal by the first and second radio base stations is corrected with a value (X) to produce a new threshold (.DELTA.AB+X). If the present voice channel activity ratio (.alpha.) of the first radio base station is equal to or greater than the threshold (.DELTA.CH) and the present voice channel activity ratio (.beta.) of the second radio base station is smaller than the threshold (.DELTA.CH), the threshold (.DELTA.AB) is corrected with a value (Y) to produce a new threshold (.DELTA.-Y).

Abstract: In order to reduce the number of measurements of signal strength for implementing a handoff of a mobile unit located in a given land site, a strength of a signal transmitted from said mobile unit is measured at the land site. Further, the land site measures a level crossing rate based on the signal transmitted from the mobile to be handed off. The land site applies a handoff request to a MTSO if the land site detects that the measured signal strength falls below a predetermined handoff threshold. The handoff request includes information indicating the level crossing rate. The MTSO compares the level crossing rate with a predetermined value, and determine a plurality of land sites each of which is to measure the signal strength for implementing a handoff according to the comparison result.

Abstract: In order to effectively control a time interval of issuing a handoff request from a land site in a mobile communications system, a strength of a signal which is transmitted from a mobile unit located in a service area of said land site, is measured at the land side. A level crossing rate is measured based on the signal transmitted from the mobile unit. A first handoff request is generated if the signal strength falls below a predetermined handoff threshold. Following this, a timer is rendered active for counting an elapsed time after the first handoff request is generated. If the signal strength is detected below the predetermined handoff threshold, a time interval is determined based on the level crossing rate. The relationship between the time interval and the level crossing rate has been previously determined. Thereafter, a second handoff request is generated if the time interval determined in the above exceeds the elapsed time. subsequently, the timer is reset and then the above operations are repeated.

Abstract: A radio telephone switching control system having control channels which transmit/receive control data betweeen a plurality of movable terminals and a radio base station. The control channels include a mono-functional channel for access which is dedicated to access during data transmission/receiving by calling from the terminals. The control channel also includes a bi-functional channel for paging and access usable as a channel for paging one of the terminals as well as for access. The system contains a base station with a fault detector. Only one kind of control channel information is broadcast in the same service zone. All of the movable stations existing in same service zone scan the first or second range to decide the channel for access or paging according to the received control channel information. The system also sets the mono-functional channel for access and the bi-functional channel for paging and access, when a fault is not detected.