JP3972042B2 - CDMA mobile transmitter and method using the same - Google Patents

Description

  The present invention relates to a CDMA mobile transmission device such as a digital automobile phone and a cellular phone used in a cellular radio communication system and a method using the same.

  In recent years, wireless communication systems such as digital automobile phones and mobile phones have rapidly spread. A wireless communication system employs a multiple access method in which a plurality of mobile stations are connected to one base station so that many users can communicate simultaneously within a limited frequency band. As a circuit switching system of this multiple access system, a CDMA (Code Division Multiple Access) system that performs multiple processing by applying a coding process to a signal of each channel is beginning to be adopted because of high frequency utilization efficiency. .

  The transmission data timing of the conventional CDMA mobile transmission apparatus will be described with reference to FIG. FIG. 9 is a data transmission timing diagram in the conventional CDMA mobile transmission apparatus.

  FIG. 9A shows a state where there is transmission data. The transmission data generates a frame and is transmitted to the transmission destination base station. A frame refers to a data block in a synchronous communication system that is generated by periodically inserting pilot symbols (hereinafter referred to as “PL”) and transmission power control symbols (hereinafter referred to as “TPC”) into transmission data. A period from the beginning of a regularly inserted PL to the beginning of the next PL is referred to as one slot. In general, one frame is composed of 16 slots and 10 ms.

  FIG. 9B shows a transmission standby state. The state of waiting for transmission is less than K frames after the transmission of transmission data is completed, or while a frame in which the CRC detection result of received data is NG is less than L frames (K and L are set in advance) State). In the transmission standby state, the CDMA mobile transmission device generates a frame (hereinafter referred to as “burst frame”) consisting only of PL and TPC, and generates data (hereinafter referred to as “burst data”) generated as a burst frame at the transmission destination. Send.

  Here, CRC (Cyclic Redundancy Check) detection is a comparison between a received CRC bit and a CRC bit generated from received data for a CRC bit given by a coefficient of a remainder polynomial obtained by dividing an information bit by an nth-order generator polynomial. It is discrimination. If both match, it is determined that the received data has been correctly received (OK), and if no match is found, it indicates that there is an error in the received data (NG).

  FIG. 9C shows a transmission end state. The state in which transmission is completed refers to a state in which at least K frames have been detected since transmission data transmission has been completed, and at least L frames have been detected as a result of CRC detection of received data.

  A conventional CDMA mobile transmission device stops transmission of burst data after a predetermined time has elapsed after communication is completed in order to suppress power consumption of a transmission amplifier.

  Here, when transmission is resumed, in order for transmission power control to be possible, synchronization of transmission data needs to be established between the mobile station on the transmission side and the base station on the reception side. Until the transmission data synchronization is established, a dummy signal is transmitted instead of the transmission data, which is information from the voice or data terminal.

  The conventional CDMA mobile transmission device takes time until transmission data synchronization is established after resuming transmission, and during that time, a dummy signal, which is an unnecessary signal, must be transmitted, reducing transmission efficiency. There's a problem.

  The present invention has been made in view of the above points, and provides a CDMA mobile transmission apparatus capable of maintaining synchronization with a base station while suppressing power consumption when there is no transmission data, and a method using the same The purpose is to do.

  In order to solve the above problems, the present invention has taken the following measures.

The CDMA mobile transmitting apparatus of the present invention includes a first transmission frame generating means for generating a first transmission frame including only pilot symbols and transmission power control symbols, and a second transmission frame including pilot symbols, transmission power control symbols and transmission data. A second transmission frame generating means for generating the transmission data, a transmission means for transmitting the first transmission frame or the second transmission frame, a transmission data detecting means for detecting presence or absence of the transmission data, and a transmission data detecting means. A switching unit that switches a transmission frame transmitted by the transmission unit based on a detection result is adopted.

The CDMA mobile transmission method of the present invention includes a step of detecting presence / absence of the transmission data, a step of generating a first transmission frame including only a pilot symbol and a transmission power control symbol, a pilot symbol, a transmission power control symbol, and transmission data A step of generating a second transmission frame including: a step of transmitting the first transmission frame or the second transmission frame; a step of switching the transmission frame to be transmitted based on the presence or absence of the transmission data; The method comprising :

  ADVANTAGE OF THE INVENTION According to this invention, when there is no transmission data, the CDMA mobile transmitter which can maintain a synchronization with a base station, suppressing power consumption, and the transmission method using the same can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a CDMA mobile transmission apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 1, in this embodiment, a CDMA mobile transmission apparatus includes a data detection circuit 1 that performs ON / OFF control of data transmission from a data terminal, a data reception unit 2 that operates on reception data, and transmission data. And a timing control circuit 4 for controlling all data timings and sequences, control transmission / reception operations of data and reception data, and control data transmission / reception operations.

  The data reception unit 2 includes a reception antenna 201 that receives the reception data, a reception circuit 202 that converts the reception data to a baseband frequency, a despreading circuit 203 that detects the correlation of the converted reception data, and a reception whose correlation is detected A demodulating circuit 204 for demodulating data; and a received data converting circuit 205 for separating the demodulated received data of the frame structure into a control signal and audio data or data for data terminal, and detecting CRC, and receiving the received data in the terminal unit Send to.

  The data transmission unit 3 generates a frame by inserting PL and TPC into the transmission data and performs CRC encoding, a modulation circuit 302 that modulates the transmission data generated from the frame by various modulation methods, Spreading circuit 303 that code-spreads the modulated transmission data, conversion transmission circuit 304 that converts the spread transmission data to a desired carrier frequency, transmission antenna 305 that transmits the converted transmission data to the transmission destination base station, and reception data And a transmission power control circuit 306 that determines transmission power and TPC of transmission data according to the reception level and the like, and transmits data input from the terminal unit.

  In addition, the data transmission unit 3 includes a burst frame generation circuit 307 that generates a burst frame of only PL and TPC when transmission is OFF, a transmission interval control circuit 308 that controls a transmission interval of burst data generated from the burst frame, and data detection A switch 309 that switches the connection between the transmission data conversion circuit 301 and the transmission interval control circuit 308 with respect to the modulation circuit 302 by a transmission ON / OFF signal from the circuit 1 and synchronizes with the base station when no transmission data exists. Transmit burst data to take

  This shortens the time from when the call is resumed until synchronization is established, and by increasing the burst data transmission interval, the mobile station can reduce the power consumption of the storage battery by the transmission amplifier and lengthen the call time. it can. In addition, interference with other stations can be reduced by transmitting burst data having a slot empty.

  Data transmission timing in the CDMA mobile transmission apparatus configured as described above will be described with reference to FIG. FIG. 2 is a data transmission timing diagram of the CDMA mobile transmission device according to the first embodiment. Hereinafter, in the timing diagram, the horizontal axis represents time, and the vertical axis represents transmission power.

  First, a state where there is transmission data will be described. FIG. 2A shows a state where there is transmission data.

  When data from a voice or a data terminal is sent to the CDMA mobile transmission device, the data detection circuit 1 controls ON / OFF of data transmission from the CRC detection result of the reception data conversion circuit 205.

  When data is transmitted, the data detection circuit 1 transmits a transmission ON signal to the switch 309. The switch 309 connects the transmission data conversion circuit 301 and the modulation circuit 302 with a transmission ON signal. The transmission data is sent from the data detection circuit 1 to the transmission data conversion circuit 301. Then, the transmission data conversion circuit 301 inserts PL and TPC into the transmission data to generate a frame.

  The transmission data in which the frame is generated passes through the changeover switch 309, is modulated by the modulation circuit 302 by various modulation methods, is code spread by the spreading circuit 303, and is converted to a desired carrier frequency by the transmitting circuit 304. The data is transmitted from the transmission antenna 305 to the transmission destination base station.

  Next, a case where there is no transmission data will be described separately in a transmission standby state and a transmission end state.

  FIG. 2B shows a transmission standby state. This transmission standby state means that the transmission data has been transmitted for less than K frames, or the frame in which the CRC detection result of the received data is NG is less than L frames (K and L are preset. State). Since there is no transmission data in the transmission standby state, only burst data of PL and TPC is written, and a burst frame in which other bits are vacant space is generated.

  Since the transmission data is synchronized with the base station by transmitting the burst data, the transmission data can be transmitted immediately when the user resumes transmission. However, if burst data is continuously transmitted for a long time after the transmission is completed, the power consumption from the transmission amplifier increases and the call time decreases. If transmission of burst data is completely stopped, it takes time to synchronize transmission data when transmission is resumed. Therefore, when transmission of transmission data is finished, the following processing is performed.

  FIG. 2 (c) shows a state in which transmission has been completed. The state in which transmission is completed refers to a state in which at least K frames have been detected since transmission data transmission has been completed, and at least L frames have been detected in which the CRC detection result of received data is NG.

  First, the data detection circuit 1 transmits a transmission OFF signal to the switch 309. The switch 309 connects the transmission interval control circuit 308 and the modulation circuit 302 with the transmission OFF signal from the data detection circuit 1.

  The burst frame generation circuit 307 generates a burst frame from only PL and TPC and sends burst data to the transmission interval control circuit 308. The transmission interval control circuit 308 makes the transmission interval of burst data N times one slot (N is a natural number).

  Here, the transmission interval of burst data may be aperiodic.

  The burst data sent from the transmission interval control circuit 308 passes through the changeover switch 309, is modulated by the modulation circuit 302 by various modulation schemes, is code spread by the spreading circuit 303, and is transmitted to the desired carrier frequency by the transmission circuit 304. It is converted and transmitted from the transmission antenna to the destination base station.

  As a result, when transmission is resumed, synchronization with the base station can be achieved quickly, and the transmission interval of burst data is controlled to N times one slot (N is a natural number). Power can be reduced.

(Embodiment 2)
Next, Embodiment 2 will be described with reference to FIGS.

  FIG. 3 is a block diagram showing the configuration of the CDMA mobile transmission apparatus according to Embodiment 2 of the present invention.

  As shown in FIG. 3, in addition to the configuration of the first embodiment, the CDMA mobile transmission device according to the present embodiment repeats a pilot symbol and a transmission power control symbol in the data transmission unit 3, respectively. 310.

  By performing the repetition process, even if the transmission power of the transmission circuit 304 is reduced, the synchronization on the receiving side can be maintained, so that interference with other stations can be reduced. The circuit configuration other than the above is the same as that of the first embodiment.

  Data transmission timing in the CDMA mobile transmission apparatus configured as described above will be described with reference to FIG. FIG. 4 is a timing diagram of data transmission in the second embodiment of the CDMA mobile transmission device.

  FIG. 4A shows a state where there is transmission data. FIG. 4B shows a transmission standby state. The data transmission timing in a state where there is transmission data and in a transmission standby state is the same as in the first embodiment.

  In the present embodiment, the following processing is performed when transmission of transmission data is finished.

  FIG. 4C shows a state in which transmission has been completed. First, the data detection circuit 1 transmits a transmission OFF signal to the switch 309. The switch 309 connects the transmission interval control circuit 308 and the modulation circuit 302 with the transmission OFF signal from the data detection circuit 1.

  The burst frame generation circuit 307 generates a burst frame from only PL and TPC and sends burst data to the repetition processing circuit 310. The repetition processing circuit 310 performs repetition processing for continuously arranging pilot symbols and transmission power control symbols of burst data, and sends the data to the transmission interval control circuit 308. The transmission interval control circuit 308 sets the transmission interval of the burst data subjected to repetition processing (hereinafter referred to as “repetition processing data”) to N times one slot (N is a natural number). Note that the repetition processing data transmission interval may be aperiodic.

  The repetition processing data sent from the transmission interval control circuit 308 passes through the changeover switch 309, is modulated by the modulation circuit 302 according to various modulation schemes, is code-spread by the spreading circuit 303, and is transmitted to a desired carrier by the transmitting circuit 304. The frequency is converted and transmitted from the transmission antenna to the transmission destination base station.

  Even if the transmission power of the transmission data is reduced in the transmission circuit 304 by the repetition process, the reception side can maintain the synchronization, so that interference with other stations can be reduced.

(Embodiment 3)
Next, Embodiment 3 will be described with reference to FIGS.

  Embodiment 3 is a case where burst data is transmitted with a transmission power value extracted from received data when the base station side cannot transmit TPC in non-periodic transmission.

  FIG. 5 is a block diagram showing a configuration of a CDMA mobile transmission device according to Embodiment 3 of the present invention.

  As shown in FIG. 5, in addition to the configuration of the first embodiment, the CDMA mobile transmission device in the present embodiment uses a POW instead of TPC to control the transmission power value of burst data in the data transmission unit 3. A transmission power control circuit 311 and a switch 312 that switches connection between the transmission power control circuit 306 and the burst transmission power control circuit 311 with respect to the transmission circuit 304 according to a transmission ON / OFF signal from the data detection circuit 1. By setting the transmission power value of burst data to the transmission power value extracted from the received data, it is possible to prevent interference with other stations by transmitting with a power value that is too high, and receiving by transmitting with a power value that is too low It can be prevented that synchronization with the side cannot be maintained. The circuit configuration other than the above is the same as that of the first embodiment.

  Data transmission timing in the CDMA mobile transmission apparatus configured as described above will be described with reference to FIG. FIG. 6 is a data transmission timing diagram of the CDMA mobile transmission device according to the third embodiment.

  FIG. 6A shows a state where there is transmission data. FIG. 6B shows a transmission standby state. The data transmission timing in a state where there is transmission data and in a transmission standby state is the same as in the first embodiment.

  In the present embodiment, the following processing is performed when transmission of transmission data is finished.

  FIG. 6C shows a state in which transmission has been completed. First, the data detection circuit 1 transmits a transmission OFF signal to the switch 309 and the switch 312. The switch 309 connects the transmission interval control circuit 308 and the modulation circuit 302 with the transmission OFF signal from the data detection circuit 1. The switch 312 connects the transmission circuit 304 and the burst transmission power control circuit 311 by a transmission OFF signal from the data detection circuit 1.

  The burst frame generation circuit 307 generates a burst frame from only PL and POW, and sends the generated burst data to the transmission interval control circuit 308.

  The transmission interval control circuit 308 makes the transmission interval of burst data N times one slot (N is a natural number) and aperiodic.

  The burst data sent from the transmission interval control circuit 308 passes through the changeover switch 309, is modulated by the modulation circuit 302 by various modulation schemes, is code spread by the spreading circuit 303, and is transmitted to the desired carrier frequency by the transmission circuit 304. It is converted and transmitted from the transmission antenna to the destination base station.

  When the base station cannot transmit the TPC in the aperiodic transmission, the transmission circuit 304 uses the transmission power value extracted from the received data as the transmission power value of the data to transmit to the other station by transmitting with a power value that is too high. Interference can be prevented and transmission with a power value that is too low can prevent the synchronization with the receiving side from being maintained.

  Note that a repetition processing circuit 310 may be added to the present embodiment to perform repetition processing on burst data.

  FIG. 7 is a block diagram showing a configuration of a CDMA mobile transmission device in which a repetition processing circuit is added to Embodiment 3 of the present invention.

  FIG. 8 is a data transmission timing diagram of the CDMA mobile transmission device when repetition processing is performed in the third embodiment of the present invention.

  As a result, since the pilot symbols of burst data and the symbols for burst transmission power can be successively arranged, synchronization on the receiving side can be maintained even if the transmission power of transmission data is reduced. Therefore, interference with other stations can be reduced by reducing the transmission power.

  The present invention is suitable for use in a CDMA mobile transmission device such as a digital automobile phone or a cellular phone used in a cellular radio communication system.

The block diagram which shows the structure of the CDMA mobile transmission apparatus in Embodiment 1 of this invention. Data transmission timing diagram of CDMA mobile transmission device in embodiment 1 of the present invention The block diagram which shows the structure of the CDMA mobile transmission apparatus in Embodiment 2 of this invention. Data transmission timing diagram of CDMA mobile transmission apparatus in embodiment 2 of the present invention The block diagram which shows the structure of the CDMA mobile transmission apparatus in Embodiment 3 of this invention. Data transmission timing diagram of CDMA mobile transmission device in embodiment 3 of the present invention A block diagram showing a configuration of a CDMA mobile transmission device in which a repetition processing circuit is added to Embodiment 3 of the present invention. Data transmission timing diagram of CDMA mobile transmission apparatus when repetition processing is performed in Embodiment 3 of the present invention Data transmission timing diagram of conventional CDMA mobile transmitter

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Data detection circuit 2 Data reception part 3 Data transmission part 4 Timing control circuit 301 Transmission data conversion circuit 302 Modulation circuit 303 Spreading circuit 304 Transmission circuit 305 Transmission antenna 306 Transmission power control circuit 307 Burst frame generation circuit 308 Transmission interval control circuit 309 Switch 310 repetition circuit 311 burst transmission power control circuit 312 switch

Claims (8)

First transmission frame generating means for generating a first transmission frame including only pilot symbols and transmission power control symbols;
Second transmission frame generating means for generating a second transmission frame including a pilot symbol, a transmission power control symbol, and transmission data;
Transmitting means for transmitting the first transmission frame or the second transmission frame;
Transmission data detection means for detecting the presence or absence of the transmission data;
A switching unit that switches a transmission frame transmitted by the transmission unit based on a detection result of the transmission data detection unit;
A CDMA mobile transmitter comprising:   2. The transmission unit according to claim 1, wherein when the transmission data detection unit detects that there is no transmission data, the switching unit switches the transmission frame transmitted by the transmission unit from the second transmission frame to the first transmission frame. CDMA mobile transmitter.   3. The CDMA mobile transmission apparatus according to claim 2, further comprising: a transmission interval control unit that controls a transmission interval of the first transmission frame after the switching unit switches from the second transmission frame to the first transmission frame. 3. A transmission interval control unit that increases a transmission interval of the first transmission frame after the switching unit transmits a predetermined number of transmission frames after switching from the second transmission frame to the first transmission frame. The CDMA mobile transmission device described. Detecting the presence or absence of the transmission data;
Generating a first transmission frame including only pilot symbols and transmission power control symbols;
Generating a second transmission frame including pilot symbols, transmission power control symbols and transmission data;
Transmitting the first transmission frame or the second transmission frame;
Switching the transmission frame to be transmitted based on the presence or absence of the transmission data; and
A CDMA transmission method comprising: The CDMA transmission method according to claim 5, wherein when it is detected that there is no transmission data, the transmission frame to be transmitted is switched from the second transmission frame to the first transmission frame. The CDMA transmission method according to claim 6, further comprising a step of controlling a transmission interval of the first transmission frame after switching from the second transmission frame to the first transmission frame. The CDMA transmission method according to claim 6, further comprising a step of increasing a transmission interval of the first transmission frame after transmitting a predetermined number of transmission frames after switching from the second transmission frame to the first transmission frame.

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