JP3323364B2 - Mobile communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication device employing a code division multiple access and a transmission / reception same band system (CDMA / TDD system) in a digital car telephone, a portable telephone, or the like.

[0002]

2. Description of the Related Art The multiple access system is a line connection system in which a plurality of stations simultaneously communicate in the same band. CDMA (Code Division Multiple Access) refers to code division multiple access, and performs multiple access by spread spectrum communication in which the spectrum of an information signal is spread and transmitted over a band that is sufficiently wider than the original information bandwidth. Technology. The direct spreading method is a method of directly multiplying an information signal by a spreading sequence code in spreading. CDM
In the A system, the bit rate per channel (the amount of information that can be transmitted in a fixed time) is uniquely determined by the number of spreading code sequences and the transmission speed of a transmission signal that has undergone spectrum spreading. If the bit rate of the information to be transmitted is lower than the bit rate that can be transmitted by CDMA, the transmission / reception is operated for the time required to transmit the required information amount, and the transmission / reception is stopped at other times (hereinafter, referred to as “transmission / reception”). By intermittent communication), interference to other channels (inter-station interference) can be eliminated during the suspension period, and effective use of frequency can be achieved.

[0003] TDD (Time Division Duplex) is a transmission and reception same band system, also called a ping-pong system.
This is a system in which the same radio frequency is time-divided into transmission / reception for communication, and one transmission / reception is called one frame. In the case of the TDD system, since the transmission and reception are in the same band, the frequency correlation of the fading fluctuation between the transmitted wave and the received wave is 1, and if the switching time between the two is sufficiently short, the propagation of the fading fluctuation and the like between each other will occur. Since the time correlation of the road condition is high, the mobile station controls the transmission power using the reception level from the base station (open loop power control), or the base station uses the reception wave level from the mobile station. By determining the mobile station transmission power control information and transmitting the information by adding the above information to the transmission information from the base station to the mobile station (closed loop power control), the reception level at the base station can be suppressed to a certain range. it can. Further, when the base station has a plurality of antennas, by applying transmission diversity for selecting an optimum transmission antenna from the reception level at each antenna, spatial diversity is not required at the mobile station, and the size of the mobile station can be reduced. It is possible to achieve.

FIG. 9 shows an example of the transmission / reception timing of the CDMA / TDD system viewed from the two mobile stations PS1 and PS2. In FIG. 9, the mobile stations PS1 and PS2 transmit information amount of の of the transmittable transmission amount. In order to reduce the interference between other stations and to use the frequency effectively, the mobile stations PS1 and PS2 shift the time by 4 times. Intermittent communication is performed in frame units.

[0005]

However, in the conventional mobile communication device based on the CDMA / TDD system,
Antenna selection for mobile station transmission power control and base station transmission diversity is determined from the reception result in the immediately preceding frame. However, when intermittent communication is performed when the amount of transmission bits per channel is small, continuous transmission between a plurality of frames is performed. After transmission and reception are performed, transmission and reception are stopped continuously for a plurality of frames, so the time between reception and transmission becomes longer before and after the stop period, the propagation path state changes during that time, and accurate movement at the time of starting transmission and reception There has been a problem that station transmission power control and transmission antenna selection control cannot be performed.

SUMMARY OF THE INVENTION The present invention solves such a conventional problem. In intermittent communication based on the CDMA / TDD system, the present invention is directed to mobile station transmission power control and base station transmission diversity by open loop control or closed loop control. It is an object of the present invention to provide an excellent mobile communication device capable of selecting an antenna.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for transmitting and receiving data between a base station and a mobile station continuously for a plurality of frames using a CDMA / TDD system employing a direct spreading system. In a mobile communication device that performs communication by stopping transmission and reception continuously for a plurality of frames, a base station includes a plurality of antennas, wireless transmission / reception means provided for each antenna, and a reception signal for each antenna for each channel. Means for despreading, means for comparing the correlation level obtained by the despreading between the antennas for each channel, and, based on the comparison result, the transmission signal spread at the time of transmission from any antenna for each channel. Means for selecting whether to transmit.

According to the present invention, the mobile station further comprises means for transmitting a fixed pattern before starting transmission / reception, and the base station selects a transmission antenna based on a reception result of the fixed pattern.

[0009] The present invention further comprises means for the mobile station to perform transmission power control according to the reception level of a signal transmitted from the antenna selected by the base station.

The present invention also relates to a CDM employing a direct spreading method.
In a mobile communication device in which a base station and a mobile station perform transmission and reception continuously for a plurality of frames using the A / TDD method and then stop and transmit and receive for a plurality of frames continuously, the base station includes a plurality of base stations . Antennas and settings for each antenna
The received signal at each antenna.
Means for despreading for each channel and the phase obtained by despreading
Means for comparing antenna levels between antennas for each channel
And, based on the comparison result, the transmitted signal
Select which antenna to transmit for each channel
Means for calculating transmission power control information of the mobile station based on the reception power and / or desired signal power to interference power ratio of each channel , and the base station transmits the transmission power control information to each mobile station. Means for transmitting, the mobile station,
It is provided with means for controlling transmission power based on the received transmission power control information. Also, basically the same as the above embodiment
While taking the configuration, receive power and / or
Is the transmission power control of the mobile station according to the desired signal power to interference power ratio
A comparison result of the comparing means instead of the means for calculating information;
Means for calculating the transmission power control information of the mobile station based on the
The configuration described above may be adopted.

According to the present invention, the mobile station further comprises means for transmitting a fixed pattern with a predetermined power before starting transmission / reception, wherein the base station calculates transmission power control information based on a reception result of the fixed pattern, Each mobile station controls transmission power according to transmission power control information.

[0012]

Therefore, according to the present invention, the base station compares reception correlation levels obtained by despreading signals received by a plurality of antennas between antennas for each channel, and based on the comparison result, Will select the best antenna for transmission.
It is possible to realize transmission diversity in the base station,
In the mobile station, space diversity is not required, and the size of the device can be reduced.

Further, the mobile station transmits a fixed pattern before starting transmission / reception, so that the base station selects a transmission antenna based on the reception result of the fixed pattern, and the mobile station transmits the fixed pattern from the base station. By performing transmission power control in accordance with the reception level of the signal, the optimum open-loop power control can be performed from the transmission start point.

[0014] Further, the base station calculates transmission power control information of the mobile station based on the comparison result of the reception correlation level and transmits the information to each mobile station, and each mobile station transmits based on the transmission power information. By performing power control, optimal closed-loop power control can be performed.

Furthermore, the mobile station transmits a fixed pattern before starting transmission / reception, so that the base station calculates transmission power control information based on the reception result of the fixed pattern and transmits the information to each mobile station. However, since each mobile station performs transmission power control based on the transmission power information, it is possible to perform optimal closed-loop power control from the transmission start point.

[0016]

【Example】

(Embodiment 1) FIG. 1 shows a configuration of a base station for two mobile stations PS1 and PS2 of a mobile communication apparatus according to a first embodiment of the present invention, in which two antennas A and B are provided. This is an example. 1, 101 is an antenna A, 201 is an antenna B, 102 is a transmission / reception switch for the antenna A 101, and 202 is an antenna B 201
Transmission / reception changeover switch for the antenna 103
Reference numeral 203 denotes a wireless receiving unit for the antenna B201. 104 and 105 are antennas A1
01, a despreading circuit, 204 and 205 are antennas B
201 is a despreading circuit for the PS1 circuit 100 and the PS2 circuit 200, respectively.
The received data is despread using a spreading code. 106, 2
06 is a despreading circuit 104, 105 and 204, 205
Of the correlation level (received signal power level) obtained by the despreading in antennas A101 and B20.
This is a comparison circuit for comparing between the two. 107 and 207 are synthesizing circuits for synthesizing the despread received signals in the despreading circuits 104 and 105 or 204 and 205;
A decoding circuit 8 decodes the combined received signal. 1
09 and 209 are spreading circuits for spreading transmission data by a spreading code, 110 and 210 are transmission antenna selection circuits for selecting from which antenna the spread transmission signal is transmitted, and 111 and 211 are transmission antenna selection signals thereof. is there. 112 is an addition circuit for adding the spread transmission signal for the antenna A101, 212 is an addition circuit for adding the spread transmission signal for the antenna B201, 113
Is a wireless transmission unit for the antenna A101, 213 is a wireless transmission unit for the antenna B201, and 300 is a transmission / reception switching timing signal for operating the transmission / reception switches 102 and 202.

Next, the operation of the above embodiment will be described. Received signals received by antennas A101 and B201 are primary-demodulated by radio receiving sections 103 and 203 via transmission / reception changeover switches 102 and 202, down-converted and detected, and then despread circuits 104 and
Correlation detection is performed at 5 and 204, 205. The correlation detection results obtained independently from the two antennas A101 and B201 are compared with the comparison circuits 106 and 206 in the PS1 circuit 100 and the PS2 circuit 200, respectively.
To calculate the frame average power of the correlation level (received signal power level).
And the transmission path state (transmission path transfer function) of the antenna B201, determine which of the antennas A101 and B201 to transmit at the next transmission timing, and output the transmission antenna selection signals 111 and 211. Comparison circuit 10
6 and 206 are received by the combining circuits 107 and 2
07 and are decoded by the decoding circuits 108 and 208 to obtain received data.

On the other hand, the transmission data is band-spread by spreading circuits 109 and 209 by the assigned spreading code, and then added via transmission antenna selection circuits 110 and 210 switched by transmission antenna selection signals 111 and 211. All transmission signals for which the same antenna is selected by the circuit 112 or 212 are added up, are up-converted by the radio transmission unit 113 or 213, and are transmitted through the transmission / reception switch 102 or 202 which is switched by the transmission / reception switching timing signal 300.
01 or antenna B201. In addition, in this base station configuration example, two mobile stations (PS1, PS2)
And the circuit 100 for PS1 is also
The second circuit 200 has the same configuration, but the spreading code and the despreading code are different. Further, it is possible to transmit and receive more mobile stations. In this case, the PS1 circuits 100 and the adder circuits 1 correspond to the number of connectable mobile stations.
12 and 212 are added.

FIG. 2 shows an example of the transmission / reception timing of the CDMA / TDD system as viewed from the mobile station. In FIG. 2, the mobile stations PS1 and PS2 perform transmission of an information amount of 可能 な of the transmittable transmission amount, and perform intermittent communication in units of four frames with a time lag. In the CDMA communication using the direct spreading method, it is necessary to reduce the interference between other stations in order to increase the communication quality or increase the capacity (the number of accommodated channels and the number of multiplexed channels). When performing intermittent communication, each mobile station is divided into multiple blocks of several frames (grouping)
Then, by performing communication with the base station, the number of simultaneous multiplexing can be reduced. In FIG. 2, eight frames are divided into two blocks BL1 and BL2 in units of four frames, and one block BL1 communicates with PS1 and the other block BL2 communicates with PS2.

The base station according to the present embodiment shown in FIG.
An antenna used for transmission in the second frame is selected by comparing the reception correlation level of each antenna in the frame.
Thereafter, transmission antenna selection for three frames and four frames is performed in the same manner.

As described above, according to the present embodiment, in the intermittent communication, in the second and subsequent frames from the start of the intermittent communication, the signals are received by the two antennas 101 and 201 of the base station and obtained by the comparison circuits 106 and 206. Transmission diversity for selecting an optimal transmission antenna from the received correlation level can be applied, so that spatial diversity is not required in the mobile station, and the mobile station can be downsized. If the transmission / reception timing is reversed, transmission diversity from the first frame is also possible.

(Embodiment 2) Next, a second embodiment of the present invention will be described. The configuration of the base station according to the second embodiment is the same as that of the first embodiment shown in FIG. FIG. 3 shows the configuration of the mobile station in the present embodiment. In FIG. 3, reference numeral 301 denotes an antenna for receiving a signal from a base station and transmitting the signal to the base station; 302, a transmission / reception switch for switching between transmission and reception based on a transmission / reception switching timing signal; and 303, demodulation of a signal received from the base station. A radio receiving unit for performing detection; 304, a despreading circuit for detecting the correlation of the received signal; 305, a decoding circuit for decoding the received signal to obtain received data; 306, a received power level detection for detecting the received power level of the received signal Circuit. 307 is a coding circuit for coding transmission data, 308 is a transmission power level control circuit that determines the transmission power level based on the reception power level detected by the reception power level detection circuit 306, 309
Is a spreading circuit for adding a spreading code to the transmission data to spread the data;
Reference numeral 10 denotes a guide pattern generation circuit for generating the same guide pattern as the fixed pattern of the transmission frame at the same timing.
Reference numeral 11 denotes an addition circuit that adds a spread signal and a guide pattern signal to generate a transmission signal. Reference numeral 312 denotes a wireless transmission unit that modulates the transmission signal into a wireless signal and outputs the signal from the antenna 301. Note that the transmission power level control circuit 308 determines the transmission power by using the SIR in addition to the reception power level.
(Ratio of desired wave power to interference power) can also be used. It is also possible to determine the combination of these.

FIG. 4 shows an example of a frame configuration in this embodiment. In FIG. 4, one frame includes a reception section 401.
Each transmission / reception section includes a guard time 403 for avoiding overlap between transmission and reception due to a delay in a transmission path, a fixed pattern 404 for frame synchronization and mobile station identification, and an information signal 405. It is composed of

FIG. 5 shows an example of the transmission / reception timing of the CDMA / TDD system as viewed from the mobile station. In FIG. 5, the mobile stations PS1 and PS2 perform transmission of an information amount of 可能 な of the transmittable transmission amount, and perform intermittent communication in units of two frames with a time delay. That is, this indicates that four frames are divided into two blocks BL1 and BL2 in units of two frames, and one block BL1 performs communication with PS1 and the other block BL2 performs communication with PS2. The mobile stations PS1 and PS2 transmit a guide pattern (fixed pattern) 406 from the guide pattern generation circuit 310 in FIG. 3 in the end of each transmission / reception stop section, that is, in the transmission section of the frame immediately before the transmission / reception start section. The base station receives the guide pattern 4 received by the antennas 101 and 201.
By comparing the reception correlation level 06 with the comparison circuits 106 and 206, an antenna used for transmission at the start of intermittent transmission is selected. Then, the mobile station detects the reception level of the signal transmitted from the selected antenna by the reception power level detection circuit 306, and determines the transmission power by the transmission power level control circuit 308 according to the detected reception level.
This makes it possible to realize transmission power control by appropriate transmission open loop control from the start of transmission.

As described above, according to this embodiment, the mobile station sets the guide pattern (fixed pattern) before starting transmission / reception.
The base station selects a transmitting antenna based on the reception result of the fixed pattern. Therefore, in the intermittent communication, the optimum transmitting antenna is determined based on the reception correlation level of each antenna at the base station from the frame of the intermittent communication start. Can be applied, and spatial diversity is not required in the mobile station, and the size of the mobile station can be reduced.

(Embodiment 3) Next, a third embodiment of the present invention will be described. FIG. 6 shows a configuration of the base station according to the present embodiment. The base station according to the first embodiment shown in FIG. 1 has a configuration in which reception power calculation circuits 114 and 214 and transmission power control circuits 115 and 215 are added. The configuration is the same as that of FIG. 1 except for these two circuits. Further, as shown in FIG. 7, the configuration of the mobile station is such that the transmission power control information detection circuit 313 is provided instead of the reception power level detection circuit 306 except for the guide pattern generation circuit 310 from the configuration shown in FIG. Otherwise, the configuration is the same as that of FIG.

FIG. 8 shows an example of a frame configuration of transmission information as viewed from the base station of this embodiment. In FIG.
One frame includes a transmission section 501 and a reception section 502. Each transmission / reception section includes a guard time 503 for avoiding overlap between transmission and reception due to a delay in a transmission path, and a fixed pattern for frame synchronization and mobile station identification. 504,
In the transmission section 501, the mobile station transmission power control information 506 is added before the information signal 505.

Next, the operation of this embodiment will be described.
In the base station, the reception power calculation circuits 114 and 214 calculate the reception power from the current mobile station from the reception signals selected by the comparison circuits 106 and 206, and output power or output power change amount at the time of transmission of the next mobile station. Transmission power control circuit 11
5 and 215, and transmits to the mobile station as mobile station transmission power control information 506 in addition to a part of the transmission data from the base station to the mobile station. In the mobile station, the mobile station transmission power control information 506 is detected by the transmission power control information detection circuit 313, and the transmission power level control circuit 308 controls the transmission power. In the base station, the mobile station transmission power control information 5
As input for calculating 06, SIR (desired wave power to interference power ratio) can be used in addition to the above-mentioned reception power. It is also possible to calculate by combining these.

Also in this embodiment, as shown in FIG.
PS1 and PS2 perform transmission of an information amount of の of the transmittable transmission amount, and perform intermittent communication in units of four frames with a time lag. After the start of the intermittent transmission / reception, the base station calculates the mobile station power control information 506 at the time of transmission of the second frame by each reception power of the first frame, and transmits it to the mobile station. The mobile station receives the received mobile station power control information 506.
Is used to determine the transmission power of the second frame. Thereafter, the mobile station transmission power for three frames and four frames is similarly controlled.

As described above, according to this embodiment, in the intermittent communication, the mobile station transmission power is controlled by the reception power at the base station in the second and subsequent frames from the start of the intermittent communication, so that the optimum closed loop power control is performed. Can be performed.

(Embodiment 4) The configuration of the base station and the frame configuration in this embodiment are the same as those of the third embodiment, and the configuration of the mobile station is as shown in FIG. A guide pattern generation circuit 310 is added.

Therefore, the operation of this embodiment is the same as that of the second embodiment.
And the third embodiment. As shown in FIG. 5, PS1 and PS2 transmit an information amount of １ ／ of the transmittable transmission amount, and perform intermittent communication in units of two frames with a time delay. PS1 and PS2 transmit the guide pattern (fixed pattern) 406 in the transmission section of the frame immediately before the end of each transmission and reception stop section. The base station uses the received power of the received guide pattern to
The mobile station transmission power control information is calculated as in the embodiment of the present invention, the power control information is transmitted to the mobile station from the transmission at the start of the intermittent transmission, and the mobile station controls the transmission power based on the received power control information. , Optimum closed-loop power control can be performed from the transmission start point.

[0033]

According to the present invention, as is apparent from the above embodiment, the base station compares reception correlation levels obtained by despreading signals received by a plurality of antennas between antennas for each channel. Since the optimum antenna for transmission is selected based on the comparison result, transmission diversity in the base station can be realized, and in the mobile station, spatial diversity becomes unnecessary, and the size of the device can be reduced. it can.

Further, the mobile station transmits a fixed pattern before starting transmission / reception, so that the base station selects a transmission antenna based on the reception result of the fixed pattern, and the mobile station transmits the fixed pattern from the base station. By performing transmission power control in accordance with the reception level of the signal, the optimum open-loop power control can be performed from the transmission start point.

Further, the base station calculates transmission power control information of the mobile station based on the comparison result of the reception correlation level and transmits the information to each mobile station, and each mobile station transmits based on the transmission power information. By performing power control, optimal closed-loop power control can be performed.

Furthermore, the mobile station transmits a fixed pattern before starting transmission / reception, so that the base station calculates transmission power control information based on the reception result of the fixed pattern and transmits the information to each mobile station. However, since each mobile station performs transmission power control based on the transmission power information, it is possible to perform optimal closed-loop power control from the transmission start point.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a base station according to first and second embodiments of the present invention.

FIG. 2 is a schematic diagram showing an example of timing of intermittent transmission / reception in the first and third embodiments of the present invention.

FIG. 3 is a block diagram showing a configuration of a mobile station according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing an example of a frame configuration according to the second and fourth embodiments of the present invention.

FIG. 5 is a schematic diagram showing an example of intermittent transmission / reception timing in the second and fourth embodiments of the present invention.

FIG. 6 is a block diagram showing a configuration of a base station according to the third and fourth embodiments of the present invention.

FIG. 7 is a block diagram illustrating a configuration of a mobile station according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram showing an example of a frame configuration according to the third and fourth embodiments of the present invention.

FIG. 9 is a schematic diagram showing a conventional example of intermittent transmission / reception timing;

[Explanation of symbols]

 101, 201 base station antenna A 102, 202 transmission / reception changeover switch 103, 203 radio reception unit 104, 105, 204, 205 despreading circuit 106, 206 comparison circuit 107, 207 synthesis circuit 108, 208 decoding circuit 109, 209 spreading circuit 110 , 210 Transmission antenna selection circuit 111, 211 Transmission antenna selection signal 112, 212 Addition circuit 113, 213 Radio transmission unit 114, 214 Reception power calculation circuit 115, 215 Transmission power control circuit 300 Transmission / reception switching timing signal 301 Antenna 302 Transmission / reception switching switch 303 Radio receiver 304 Despreading circuit 305 Decoding circuit 306 Received power level detection circuit 307 Encoding circuit 308 Transmission power level control circuit 309 Spreading circuit 310 Guide pattern generation circuit 311 Addition circuit 3 12 wireless transmission section 313 transmission power control information detection circuit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-334588 (JP, A) JP-A-5-206927 (JP, A) JP-A-7-283779 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04B 7/04 H04B 7/26

Claims (6)

(57) [Claims] 1. A mobile unit that performs communication by stopping transmission and reception continuously for a plurality of frames after a base station and a mobile station perform transmission and reception continuously for a plurality of frames using a CDMA / TDD system employing a direct spreading method. In the communication device, the base station includes a plurality of antennas, a radio transmission / reception unit provided for each of the antennas, a unit for despreading a received signal for each channel with each of the antennas, and a correlation obtained by the despreading. A mobile station comprising: means for comparing levels between antennas for each channel; and means for selecting from which antenna a transmission signal spread at the time of transmission is to be transmitted for each channel based on the comparison result. Body communication device. 2. The mobile station further comprises means for transmitting a fixed pattern before starting transmission / reception, and the base station selects a transmission antenna based on a result of receiving the fixed pattern.
The mobile communication device according to claim 1. 3. The mobile station according to claim 2, wherein the mobile station includes means for performing transmission power control in accordance with a reception level of a signal transmitted from an antenna selected by the base station or a desired signal power to interference power ratio. Body communication device. 4. A mobile unit, in which a base station and a mobile station perform transmission / reception continuously for a plurality of frames using a CDMA / TDD system employing a direct spreading method, and then stop transmission / reception for a plurality of frames to perform communication. In a communication device, a base station includes a plurality of antennas and a radio provided for each of the antennas.
Transmitting / receiving means, and receiving signals by each antenna for each channel
Means for despreading, and a correlation level obtained by the despreading.
Means to compare the bells between antennas for each channel, and
Based on the comparison result, the transmitted signal
Select which antenna to transmit for each channel
Means for calculating transmission power control information of the mobile station based on reception power or desired signal power to interference power ratio for each channel , and the base station transmits the transmission power control information to each mobile station. A mobile communication device comprising: means for transmitting; and means for controlling, by the mobile station, transmission power based on the received transmission power control information. 5. A CDMA / TDD method employing a direct spreading method.
Base station and mobile station
After transmitting and receiving with
In a mobile communication device that performs communication by stopping, a base station
Are a plurality of antennas, and a radio provided for each of the antennas.
Transmitting / receiving means, and receiving signals by each antenna for each channel
Means for despreading, and a correlation level obtained by the despreading.
Means to compare the bells between antennas for each channel, and
Based on the comparison result, the transmitted signal
Select which antenna to transmit for each channel
Means for controlling the transmission power of the mobile station based on the comparison result of the comparing means.
Means for calculating information, and moving the transmission power control information
Means for transmitting to the station, wherein the mobile station
A mobile communication device comprising means for controlling transmission power based on communication power control information . 6. The mobile station further comprises means for transmitting a fixed pattern with a predetermined power before starting transmission / reception.
The mobile communication device according to claim 4, wherein a base station calculates transmission power control information based on a reception result of the fixed pattern, and each mobile station controls transmission power based on the transmission power control information.