Communication terminal and method for selecting transmitting station

Abstract

A communication terminal in soft handover selects a base station device transmitting a downlink signal for each selection / synthesis unit at the base station device based on the quality judgment results of downlink from a plurality of base station devices, and the selected base station device transmits a downlink message. When the difference between the receiving power of a downlink signal from the selected base station device and the maximum receiving power of the downlink signals from other base station device exceeds a predetermined value, the base station device transmitting the downlink signal with maximum receiving power is selected.

Description

technical field [0001] The present invention relates to a communication terminal device and a method for selecting a transmitting station used in a digital wireless communication system. Background technique [0002] figure 1 It is a schematic explanatory diagram of handover in which a base station with which a communication terminal communicates is switched in a conventional digital wireless communication system. [0003] In soft handover from the first base station 1, which is the base station where the communication terminal 4 is communicating, to the second base station 2, which will communicate, the communication terminal 4 communicates with both the first and second base stations. At this time, the console 3 selects a signal with a good reception state from the signals from the first and second base stations, and synthesizes a received packet using the selected received signal as a transmission signal from the communication terminal. [0004] A communication terminal...

AI Technical Summary

Problems solved by technology

[0006] However, in the case of unstable signal propagation near the cell border like during handover, even if the base station with good channel quality is selected and switched to transmit the downlink to the corresponding communication terminal according to the quality of each transmission unit of the downlink in the communication terminal, The base station of the signal, the quality of the downlink signal from the base station may also deteriorate, and it cannot be received correctly by the communication terminal

[0007] That is, in the transmission of a plurality of transmission units constituting the signal selection and combination unit in the communication terminal, when the base station for transmitting the downlink signal is switched, the base station to be switched may not be the target of transmission power control with the communication terminal so far. The transmission unit is erroneously received by the communication terminal due to the incompatibility of the downlink transmission power control due to the transmission error of the transmission power control information that occurred before the handover, or the rapid quality deterioration.

In this case, the selection and synthesis unit cannot be correctly configured at the communication terminal, and as a result, there is a problem that the selection and synthesis unit needs to be retransmitted, and efficient communication cannot be performed.

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