Telecommunications – Transmitter – With feedback of modulated output signal
Reexamination Certificate
1999-04-08
2001-10-16
LeGree, Tracy (Department: 2681)
Telecommunications
Transmitter
With feedback of modulated output signal
C455S127500, C455S234100, C330S129000, C330S279000
Reexamination Certificate
active
06304749
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a radio equipment such as a mobile telephone employed in a mobile communication, a transmit power controlling method in the radio equipment, and a recording medium for recording a program to execute the transmit power controlling method.
In the mobile communication device such as the mobile telephone employed commonly, a function for controlling its own transmit power according to a distance between a base station and a mobile station in transmitting information is installed. In order to improve a frequency utilization efficiency by reducing interference between communication channels, transmit power control for keeping constant a power of the signal which can reach the base station is essential in a multiple access type communication system for multiplying a plurality of communication channels.
In particular, in the mobile communication device of CDMA (Code Division Multiple Access) system by using the spread spectrum technology, there is a high possibility that the so-called far-and-near problem is caused, and the interference with others must be suppressed to the lowest minimum. Therefore, transmit power control to enable a wide dynamic range (e.g., 70 to 80 dB) and high linearity is requested. In the wideband CDMA (W-CDMA) system which is examined now as a next generation mobile communication system, precision request of transmit power becomes higher in high power transmission and also transmit power control with higher precision is requested.
The transmit power control is classified into two types, i.e., “open loop control” in which an intensity of signal supplied from the base station is measured by the mobile station and then transmit power of the mobile station is adjusted based on measured results, and “closed loop control” in which the intensity of signal supplied from the mobile station is measured by the base station, then transmit power controlling data are transmitted from the base station to the mobile station based on measured results, and then a transmit power of the mobile station is adjusted according to the data. In the current mobile communication device, it is common that “power precision compensation control” is not executed wherein transmit power can be suppressed within a predetermined range relative to a target value in the mobile station in itself when the above transmit power control is effected, but merely “limiting control” is executed wherein transmit power can be suppressed not to exceed an allowable upper limit value of transmit power is effected.
However, according to the above radio equipment in the prior art, in the communication circumstances in which transmit power control of wide dynamic range and high linearity is needed, it has been difficult to assuring absolute precision of the transmit power (allowable error of the variable range in the transmit power control) while keeping power variable amount precision (allowable error of the power control target value) when the transmit power being output from the mobile station is controlled variably, so that sometimes it has been difficult to satisfy transmit power precision being specified by the radio law or regulation at the maximum power transmission. In addition, there is a possibility that, if the mobile station comes closest to the base station, the interference with others is increased. Further, it is possible to cause various disadvantages in practical use since the connection is easily disconnected if the mobile station goes farthest from the base station.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances in the conventional art, and it is an object of the present invention to provide a radio equipment, a transmit power controlling method in the radio equipment, and a recording medium such advantages can be achieved that the transmit power precision compensating function for converging the transmit power into the predetermined range of the power control target value can be achieved in the radio equipment in which necessary absolute precision of the transmit power can be assured while keeping the power variable amount precision in transmit power adjustment and the transmit power control of wide dynamic range and high linearity also is requested.
According to the present invention, a radio equipment comprises transmit power designating means for designating a transmit power of a transmit signal transmitted from the radio equipment; control reference value generating means for generating a reference value of transmit power control based on the transmit power being designated; timing controlling means for specifying a control timing of the transmit power; error detecting means for detecting an error based on difference between a detected value of the transmit signal from the radio equipment and a detected value of the transmit signal when it is transmitted by the transmit power being designated; gain multiplying means for multiplying a detected error by a predetermined gain to calculate a correction value; control amount generating means for generating a control amount based on the correction value; and power adjusting means for adjusting the transmit power by re-setting a gain in transmit power amplification at the control timing, based on a reference value of the transmit power control and the control amount; wherein the predetermined gain is set such that an amount of change in the transmit power which is adjusted based on the control amount can be suppressed in an allowable range which is requested for an amount of change in the transmit power being adjusted based on the reference value.
Furthermore, according to the present invention, the control amount generating means generates a control amount by adding the correction value, which is effected according to the control timing, every control unit, and the predetermined gain is set such that an amount of change in the transmit power which is adjusted based on the control amount per one control unit can be made smaller than an allowable range requested for an amount of change in the transmit power which is adjusted based on the reference value.
Furthermore, the control amount generating means generates a control amount by subtracting, every control unit, a predetermined value which is set such that an amount of change in the transmit power per one control unit can be made smaller than an allowable range requested for an amount of change in the transmit power which is adjusted based on the reference value when the transmit power of the transmit signal is less than a predetermined power.
Still further, according to the present invention, a radio equipment comprises a gain variable setting means for setting the predetermined gain variably based on an error detected by the error detecting means such that the correction value is fixed constant.
Still further, according to the present invention, a gain setting means for setting the predetermined gain every transmission mode in answer to a level of an allowable range requested for an amount of change in the transmit power being adjusted based on the reference value; a transmission mode deciding means for deciding the transmission mode; and a selecting means for selecting a predetermined gain which corresponds to a decided transmission mode from the gain setting means.
Moreover, according to the present invention, a transmit power controlling method in a radio equipment, comprising the steps of: transmit power designating step of designating a transmit power of a transmit signal transmitted from the radio equipment; control reference value generating step of generating a reference value of transmit power control based on the transmit power being designated; error detecting step of detecting an error based on difference between a detected value of the transmit signal from the radio equipment and a detected value of the transmit signal when it is transmitted by the transmit power being designated; gain multiplying step of multiplying a detected error by a predetermined gain to calculate a
Gary Erika A.
Legree Tracy
Matsushita Electric - Industrial Co., Ltd.
Pearne & Gordon LLP
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