JPH11275036A - Communication terminal device, base station communication device, and wireless communication system - Google Patents

Abstract

(57) Abstract: CDMA / TDD having TDMA structure
(1) To suppress interference between systems during home service. SOLUTION: In the CDMA / TDD system, TDMA
By using a signal having a structure, by transmitting and receiving the broadcast channel only in the last downlink slot of the subframe,
Flexible support for various services, avoiding interference problems, especially in self-employed services. In addition, the base station communication apparatus repeatedly transmits the number of times that the information included in the broadcast channel is divided by time, and devises uplink and downlink slot assignments to take advantage of characteristics of uplink open loop transmission power control and base station transmission diversity. be able to.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication terminal device such as a mobile station communication device used for digital radio communication, a base station communication device, and a radio communication system.

[0002]

2. Description of the Related Art In the field of digital radio communication, a multiple access method has been adopted as a line connection method when a plurality of stations simultaneously communicate in the same band.
e Division Multiple Access) and CDMA (Code Divisio
n Multiple Access). TDMA is a time division multiple access, which is a multiple access technique in which an information signal is temporally compressed and transmission / reception is performed within an assigned time slot. CDMA is code division multiple access, and is a technique for performing 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. here,
The direct spreading method is a method of directly multiplying an information signal by a spreading code sequence in spreading.

On the other hand, in the wireless communication technology, FDD (Frequency Divisi
A duplex system such as an "on Duplex" system or a TDD (Time Division Duplex) system is employed. For example, TD
D is a transmission and reception same band method, also called a ping-pong method, which is a method of performing communication by time-dividing the same radio frequency into transmission / reception. Since the TDD system does not require an up / down pair band, it is conceivable that the TDD system will be applied not only to public services but also to private or home services. In addition, the TDD scheme has an advantage that an asymmetric transmission rate service can be easily performed by flexibly responding to a difference in uplink traffic and a difference in service.

In a specific application, a multiple access communication system such as TDMA or CDMA described above,
In some cases, a communication method such as DD or TDD is combined. In particular, the CDMA / TDD method is expected to be widely used in the future because the number of accommodated lines can be efficiently increased.

[0005] In the case of the CDMA / TDD system, the ARIB Volum
e 3 "Specifications of Air-Interface for 3G Mobile
As described in System (Ver.0.5), it is considered that the amount of interference between systems is suppressed by transmitting over the entire frame using different spreading codes in uplink and downlink.

[0006] Also, information unique to the base station apparatus, such as downlink transmission power and uplink interference power, is transmitted over the entire frame through a spread broadcast channel (BCCH). However, when the base station communication apparatuses are very close to each other, even if different spreading codes are used, the amount of interference power increases, so that the characteristics of the system may be degraded.

[0007]

FIG. 9 shows a conventional CDM.
3 shows a downlink frame structure when the A / TDD method is introduced into a home service and an uplink / downlink symmetric service is performed. As can be seen from FIG. 9, the communication channel and the broadcast channel are divided into a plurality of downlink slots, and the information to be transmitted is transmitted over one entire frame.

On the other hand, in recent years, with the advancement of cellular system technology, a self-owned (home) system has been developed in which communication is performed by freely selecting the arrangement of time slots in signal frames in up and down directions. At this time, the commonality between public services and home services should also be considered. However, the conventional method cannot cope with such a self-employed system at all.

Further, in FIG. 9, the broadcast channels of the four systems use a common slot. However, as the number of operating systems becomes denser, the amount of interference by the broadcast channels increases.

[0010] The present invention has been made in view of the above points, and it is a communication terminal apparatus, a base station communication apparatus, and a wireless communication apparatus capable of suppressing interference between systems and commonly supporting a public service and a home service. The purpose is to provide a system.

[0011]

The gist of the present invention is a CDM.
By using a signal having a TDMA structure in the A / TDD system and transmitting / receiving a broadcast channel only in the last downlink slot of a subframe, various services can be flexibly supported, and the problem of interference in a self-service is avoided. In addition, the base station communication apparatus repeatedly transmits the number of times that the information included in the broadcast channel is divided by time, and devises uplink and downlink slot assignments to take advantage of characteristics of uplink open loop transmission power control and base station transmission diversity. be able to.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication terminal apparatus according to a first aspect of the present invention uses a signal composed of a TDMA frame including a subframe composed of a plurality of time slots and a base station in a CDMA / TDD system. A configuration is provided including communication control means for communicating with a communication device, and demodulation means for demodulating only a broadcast channel signal received at a timing corresponding to the last downlink time slot in the subframe.

According to this configuration, since the slot configuration in the subframe can be set freely, it is possible to flexibly cope with various services and avoid the interference problem particularly in the self-service. Also, since only the broadcast channel signal received at the timing corresponding to the last downlink time slot is demodulated, the power required for demodulation can be reduced.

According to a second aspect of the present invention, in the communication terminal apparatus according to the first aspect, each of the broadcast channel signals includes the same data, and the demodulation unit combines the broadcast channel signals by a unit frame. A configuration for obtaining demodulated data is employed.

According to this configuration, the same broadcast channel data can be distributed to downlink slots for a plurality of subframes, so that the transmission power of the broadcast channel signal transmitted for one subframe can be reduced.

According to a third aspect of the present invention, in the communication terminal apparatus according to the first or second aspect, the error detection means for detecting a code error of the broadcast channel signal and the demodulation means according to an error detection result. And a demodulation stop instruction means for instructing a stop of demodulation.

According to a fourth aspect of the present invention, in the communication terminal apparatus according to the third aspect, the demodulation stop instructing means demodulates a broadcast channel signal received thereafter when the error detection result is good. A configuration for instructing the demodulation means to stop is adopted.

According to these configurations, it is possible to detect an error in broadcast channel data distributed to downlink slots corresponding to subframes, and to detect one error with the least demodulated data.
Information for a frame can be obtained.

The communication terminal apparatus according to a fifth aspect of the present invention is the communication terminal apparatus according to the fourth aspect, wherein the demodulation means receives another broadcast after receiving an instruction from the demodulation stop instruction means to stop demodulation of the broadcast channel signal. A configuration for demodulating a channel signal is employed.

According to this configuration, reception of information for one frame can be completed in as few slots as possible, that is, in a time as short as possible, and the remaining time in one frame is reserved for cell search as a demodulation idle time. be able to.

[0021] In a communication terminal apparatus according to a sixth aspect of the present invention, in the first aspect, the demodulation means may include only a system-specific broadcast channel signal which is a last downlink broadcast channel signal in the subframe. The demodulation configuration is adopted.

According to this configuration, if there is no problem in the amount of interference, a plurality of base station communication apparatuses (systems) can use the same subframe. Further, when there is no problem in the amount of interference, even if the transmission speed becomes insufficient, it is possible to use still another subframe.

In a communication terminal apparatus according to a seventh aspect of the present invention, in any one of the first to fifth aspects, the communication control means uses a first time slot in a subframe in an uplink and a last time slot in a subframe. A configuration that operates in a system using a time slot in a downlink is adopted.

According to this configuration, since the communication terminal device only needs to receive the broadcast channel in a specific slot, the slot configuration of each subframe can be easily changed, and the system design is flexible. Can be provided. For example, by simply fixing the slot in which the broadcast channel signal is present and changing the allocation of the uplink slots and the downlink slots, it is possible to cope with both the target transmission system and the asymmetric transmission system.

[0025] The communication terminal apparatus according to an eighth aspect of the present invention employs, in the seventh aspect, a configuration in which a frame includes a subframe in which the configuration of slots other than the first and last time slots is different.

According to this configuration, since the base station communication device only needs to transmit the broadcast channel in a specific slot, the slot configuration of each subframe can be easily changed, and the system design is flexible. It can have sex. For example, by simply fixing the slot in which the broadcast channel signal is present and changing the allocation of the uplink slots and the downlink slots, it is possible to cope with both the target transmission system and the asymmetric transmission system.

[0027] The communication terminal apparatus according to a ninth aspect of the present invention is the communication terminal apparatus according to any one of the first to eighth aspects, which measures the quality of a broadcast channel signal received immediately before the first time slot in the subframe. Means and means for controlling uplink transmission power based on the measurement result.

According to this configuration, the CDM having the TDMA structure is used.
In communication using the A / TDD method, a broadcast channel can be monitored at an appropriate timing to realize accurate transmission power control and base station transmission diversity. T
By adopting the DMA structure, even when the interval between the uplink slot and the downlink slot is wide, the transmission power control can be performed with high accuracy in the communication terminal device, and the transmission power control and the base station can be performed with high accuracy even in the base station communication device. Transmit diversity can be performed. Further, by employing the TDMA structure, the interference problem can be mitigated.

[0029] A base station communication apparatus according to a tenth aspect of the present invention uses a signal composed of a frame in a TDMA structure including a subframe composed of a plurality of time slots.
A communication control means for communicating with a communication terminal apparatus in a DMA / TDD system, and a transmission control means for transmitting a broadcast channel signal only at a timing corresponding to a last downlink time slot in the subframe. take.

According to this configuration, since the slot configuration in the subframe can be set freely, it is possible to flexibly cope with various services and to avoid the problem of interference particularly in the private service. Further, since the broadcast channel signal is transmitted only at the timing corresponding to the last downlink time slot, it is possible to suppress interference with other stations.

The base station communication apparatus according to an eleventh aspect of the present invention is the base station communication apparatus according to the tenth aspect, wherein the transmission control means sets a system-specific broadcast channel at a timing corresponding to a last downlink time slot in the subframe. A configuration for controlling the signal transmission is adopted.

According to this configuration, if there is no problem in the amount of interference, a plurality of base station communication apparatuses (systems) can use the same subframe. Further, when there is no problem in the amount of interference, even if the transmission speed becomes insufficient, it is possible to use still another subframe.

[0033] In the base station communication apparatus according to a twelfth aspect of the present invention, in the tenth or eleventh aspect, the transmission control means uses a first time slot in a subframe in an uplink and a last time slot in a subframe. Is adopted in a system that operates on a downlink.

According to this configuration, since the base station communication device only needs to transmit the broadcast channel in a specific slot, the slot configuration of each subframe can be easily changed, and the system design is flexible. It can have sex. For example, by simply fixing the slot in which the broadcast channel signal is present and changing the allocation of the uplink slots and the downlink slots, it is possible to cope with both the target transmission system and the asymmetric transmission system.

A base station communication apparatus according to a thirteenth aspect of the present invention is the base station communication apparatus according to any one of the tenth to twelfth aspects, wherein the TPC information generated by the communication terminal apparatus based on the quality of the broadcast channel signal is transmitted to an uplink. TPC information acquisition means for acquiring from the communication channel signal of the above, transmission power control means for performing downlink transmission power control based on the TPC information,
Is adopted.

According to this configuration, since the open-loop transmission power control on the uplink and the closed-loop transmission power control on the downlink can be realized in combination, the accuracy of the transmission power control is improved.

A wireless communication system according to a fourteenth aspect of the present invention includes the communication terminal device according to any one of the first to ninth aspects,
A base station communication device that performs wireless communication with the communication terminal device;
Is adopted.

[0038] A wireless communication system according to a fifteenth aspect of the present invention includes the base station communication apparatus according to any one of the tenth to fourteenth aspects, and a communication terminal apparatus that performs wireless communication with the base station communication apparatus. It adopts the configuration to do.

According to these configurations, since the slot configuration in the subframe can be set freely, it is possible to flexibly cope with various services and to avoid the problem of interference particularly in the private service.

A wireless communication method according to a sixteenth aspect of the present invention comprises:
The base station communication apparatus transmits the broadcast channel signal only at the timing corresponding to the last downlink time slot in the subframe of the communication channel signal framed in the TDMA structure including the subframe composed of a plurality of time slots. Performing, the communication terminal device receiving the broadcast channel signal at the timing, and demodulating the broadcast channel signal.

According to this method, since the slot configuration in the subframe can be set freely, it is possible to flexibly cope with various services and to avoid the problem of interference particularly in the private service.

A wireless communication method according to a seventeenth aspect of the present invention comprises:
In a sixteenth aspect, a step of detecting a code error of the broadcast channel signal, and when the error detection result is good, instructing the demodulation means to stop demodulation of a broadcast channel signal received thereafter. And a step.

According to this method, it is possible to detect an error in broadcast channel data distributed to downlink slots corresponding to subframes, and to obtain information for one frame with the least demodulated data.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. (Embodiment 1) FIG.
FIG. 3 is a block diagram showing a configuration of a communication terminal device in the wireless communication system according to Embodiment 1 of the present invention. This communication terminal device mainly includes one or a plurality of antennas 101, a receiver 100, a transmitter 107, and a transmission / reception slot control unit 112.

The receiver 100 has a CDM for a communication channel.
A demodulator 102 and CDMA demodulator 1 for broadcast channel
03, a reception slot control section 104 for controlling the reception slot timing for demodulation, a reception signal strength measuring device 105 for measuring the reception signal strength of the control channel signal, and SIR (signal-to-interference ratio) ) Is measured.

The transmitter 107 is provided with a downlink TPC
Bit generation unit 108, slot configuration unit 109, CD
An MA modulator 110 and a transmission power control unit 111 are provided. Then, the transmission / reception slot control unit 112 controls the transmission / reception slot timing between the receiver 100, the transmitter 107, and another user.

FIG. 2 is a block diagram showing a configuration of a base station communication device in the radio communication system according to Embodiment 1 of the present invention. This base station apparatus mainly includes one or a plurality of antennas 201, a receiver 200, a transmitter 205, a transmission / reception slot control unit 209, and an uplink / downlink traffic monitor unit 210.

The receiver 200 includes a CDMA demodulator 202
, Antenna reception power comparator 203, downlink TP
And a C-bit demodulation unit 204. Transmitter 205
Are the CDMA modulator for communication channel 206, the transmission power control unit 207, the antenna selection control unit 208, the CDMA modulator for broadcast channel 211 (common to all users), the transmission slot control unit 212, and the number of antennas. Adder 21
3 and transmission Nyquist filters 214 for the number of antennas
, D / A converters 215 for the number of antennas, and quadrature modulators 216 for the number of antennas. Further, a transmission / reception slot control unit 209 controls a transmission / reception slot between the receiver 200, the transmitter 205, and another user. In addition, the upstream / downstream traffic monitor unit 210 monitors the upstream / downstream traffic state, and sends the information to the transmission / reception slot control unit 209.

Next, an operation in a radio communication system accommodating the communication terminal device and the base station communication device having the above configuration will be described.

First, the uplink and downlink traffic or service status is monitored by the uplink and downlink traffic monitor unit 210 on the base station communication apparatus side, and for example, whether the service is a public service or a home service. The transmission / reception slot control unit 209 determines and controls the transmission / reception slot configuration pattern based on the obtained result. The transmission / reception slot configuration pattern will be described later.

In the base station communication apparatus, the reception signal taken into the receiver 200 for each code, that is, the code of the communication channel and the code of the broadcast channel by the transmission / reception slot control section 209 is demodulated into data by the CDMA demodulator 202. Is done. Also, a TPC bit demodulation unit 2 for downlink
In 04, downlink TPC bits are obtained from the received signal and demodulated.

[0052] The demodulated TPC information is sent to transmission power control section 207. Further, the received signal is also taken into antenna received power comparator 203, selects the antenna with the best propagation path condition, and sends the antenna selection control signal to antenna selection control section 208.

Next, a transmission signal is generated for each code by the communication channel CDMA modulator 206, transmission power control is performed by the transmission power control unit 207, and broadcast channel data common to all users is also transmitted by the transmission slot control. Part 2
12 and is generated by the CDMA modulator 211. The broadcast channel data is accommodated with the same power in one slot of each subframe constituting the frame. Alternatively, the broadcast channel data is accommodated in one slot of each subframe constituting a frame as system-specific data. Note that antenna selection is not performed for the broadcast channel.

The transmission signal for each generated code is
The signal is output at the transmission slot timing by the transmission / reception slot control unit 209, added by the adder 213 for each antenna, waveform-shaped by the Nyquist filter 214, and D / A
After the D / A conversion by the converter 215, the quadrature modulator 21
The signal is orthogonally modulated at 6 and transmitted. Note that the broadcast channel signal is transmitted only at a timing corresponding to the last downlink time slot in a subframe of a communication channel signal framed in a TDMA structure including a subframe formed of a plurality of time slots.

On the other hand, in the communication terminal device, the transmission / reception slot control section 112 controls the transmission / reception slot configuration pattern based on the transmission / reception slot configuration information transmitted from the base station communication device. The received signal captured by the receiver 200 by the transmission / reception slot control unit 112 is a communication channel C
The data is reproduced by the DMA demodulator 102 and is demodulated by the broadcast channel CDMA demodulator 103 under the control of the reception slot control unit 104. C for broadcast channel
The DMA demodulator 103 transmits only a broadcast channel signal received at a timing corresponding to the last downlink time slot in a subframe of a communication channel signal framed in a TDMA structure including a subframe formed of a plurality of time slots. Is demodulated. As a result, power consumption due to demodulation in the communication terminal device can be reduced.

The received signal is a CDM for a communication channel.
The signal is sent from A demodulator 102 to SIR measuring device 106, the received SIR is measured, and a downlink closed loop transmission power control signal is sent to downlink TPC bit generating section 108 of transmitter 107 based on the result. Downlink TP
The C bit is sent to slot forming section 109 to form a slot, and is carried on the transmission signal.

On the other hand, the broadcast channel signal is sent from the broadcast channel CDMA demodulator 103 to the received signal strength measuring device 105.
, The received signal power is measured, and an uplink open-loop transmission power control signal is transmitted to the transmission power control section 111 of the transmitter 107 based on the measurement result. Next, this transmission signal is modulated by CDMA modulator 110 and transmitted by transmission / reception slot control section 112 via transmission power control section 111.

Here, a transmission / reception slot configuration pattern controlled by the above-described base station communication apparatus will be described with reference to FIG. This slot configuration pattern corresponds to one frame (1
(6 slots) are divided into several subframes, and a transmission / reception timing pattern is determined for each subframe based on the traffic monitoring result. In addition,
The number of subframes is equal to the number of TDMA multiplexes in the TDMA structure.

FIG. 3 shows a case where one frame is divided into four sub-frames. The number of subframes may be a number other than four, for example, two or eight. In the subframe, for example, if the first slot is fixed to the up slot and the last slot is fixed to the down slot, the slots between them can be selected from a plurality of patterns (four). In the case of FIG. 3, <up, down, down,
Down>, <Up, Down, Up, Down>, <Up, Up,
Up, down> and <up, up, down, down> can be selected from four patterns. This makes it possible to flexibly cope with various services including asymmetric services. In particular, if the TDMA structure is adopted for the frame structure, a different slot structure can be used for each subframe, and it is possible to flexibly cope with the self-service. Although the case where the first (first) slot and the last slot are fixed has been described above, the first (first) slot and the last slot need not be fixed.

Normally, when an uplink slot and a downlink slot are assigned to the same slot timing with a base station communication device located in the vicinity, a large interference problem occurs, so that the same transmission / reception slot configuration is used. If control is desirable but interference is not an issue,
Each base station communication device may use a different transmission / reception slot configuration.

In the present embodiment, the broadcast channel (BCCH) is transmitted using the last downlink slot of each subframe. The broadcast channel has a different transmission method depending on a public service and a home service (private service or private service), but has the same basic configuration.

FIG. 4 shows a broadcast channel structure for a public service when the number of subframes is four. Each base station communication device transmits broadcast channel information 401 to be transmitted only in the last downlink slot of a subframe, and repeatedly transmits the same information in the last downlink slot of all subframes. Since the same information is repeatedly transmitted in this manner, the transmission power of the broadcast channel signal transmitted for one subframe can be suppressed low. In this broadcast channel information, information A to D for communication terminal apparatuses BS # 1 to BS # 4 is compressed and stored in the last downlink slot. As described above, since the broadcast channel information 401 to be transmitted is transmitted only in the last downlink slot of the subframe, it is possible to suppress interference due to the broadcast channel.

Compared with the conventional case where the broadcast channel information is transmitted over one frame, if the transmission power is substantially the same, the reception signals of all subframes are synchronously added for a unit frame, for example, one frame. Thus, the same reception quality can be obtained.

Further, since transmission power control is not applied to the broadcast channel, there is a large variation in reception quality due to fading. Therefore, when the propagation environment is good, several subframes in a frame, for example, 1
Information can be obtained only by receiving a broadcast channel of a subframe, and there is no need to receive a broadcast channel in a subsequent subframe. In this case, an instruction to stop demodulation of the broadcast channel signal is issued to provide an idle time for demodulation. This idle time can be, for example, different frequency carriers,
Alternatively, it can be used as a monitor for performing handover to another system. The details will be described later.

FIG. 5 shows a broadcast channel structure for a home service when the number of subframes is four. Each base station communication device (each system) determines which subframe to use for communication at the time of initial operation of the system,
The broadcast channel 501 to be transmitted is transmitted only in the last slot of the subframe. If there is no problem with the amount of interference,
Multiple base station communication devices (systems) using the same subframe
May be used. According to this method, the achievable maximum transmission rate is lower than in the case where communication is performed using the entire frame. However, when there is no problem in the amount of interference, when the transmission rate is insufficient, another sub-rate is used. It is also possible to use frames. In the case shown in FIG. 5, the system may be such that the broadcast channel information of the last slot of one subframe is synchronously added over a plurality of frames to obtain information.

Next, a method in which the communication terminal apparatus forms the above-mentioned idle time for demodulation will be described with reference to FIGS. FIG. 6 is a block diagram showing a main part of the communication terminal apparatus according to the present embodiment, and FIG. 7 is a flowchart for explaining a demodulation idle time forming process according to the present embodiment.
Here, the description will be made by replacing the slots with the blocks.

First, the configuration will be described with reference to FIG. The antenna 601 receives the RF signal and sends it to the RxRF unit 603 via the RxRF switching unit 602 described later. RxR
F section 603 drops the received signal from the carrier frequency to the baseband frequency. Further, the A / D converter 604 converts the digital signal, and the RAKE combining / demodulating unit 605 performs RAKE combining.

Next, the received signal entering the different system control channel reading section 600 is transmitted to the block data memory 6.
Enter 06. There are n block data memories 606,
The first block data memory stores the data of the first block of the broadcast channel repeatedly transmitted at least at twice the rate from the transmitting / receiving device on the base station side. The n block data memories are sequentially stored for each block in one frame. n can be arbitrarily determined. As will be described in detail later, since n is required to be equal to or more than the number of blocks in one frame, the minimum value of n is determined by how many times the transmission / reception apparatus at the base station transmits. The block data memory storage controller 607 stores the data of each block in the block data memory 606.

The block decoding unit 608 includes a block data memory 606 or a block addition data memory 6 described later.
12 is decrypted. This decoding is performed in block units or in added block units.

The error detection unit 609 performs error detection of the decoded data, and outputs the detection result to the block data memory storage control unit 607, an addition control unit 610, an in-frame control channel read control unit 613, and an RxRF unit selection. Notify to the control unit.

The number of the adders 611 is n−1, and the block data memory 606 or the block data addition memory 612 is used.
Are added and stored in the block data addition memory 612. The addition control unit 610 sends the data that has been added and stored in the block addition data memory 612 to the block decoding unit 608 to be decoded. In order to reduce the size of the apparatus, the block data memory 606, the adder 611, and the addition data memory 612 of the different system control channel reading unit are provided one by one, and are repeatedly used in subframe units in a frame. Similar processing can be performed.

When the RxRF section selection control section 613 receives a notification from the error detection section 609 that the error rate is equal to or less than the threshold value, it switches the RxRF switching section 602 to operate the RxRF section 614 for a different system. That is, RxR
The reception of the broadcast channel using the F unit 603 is stopped.
The demodulation processing unit 615 for a different system uses the RxR
The control unit 614 performs A / D conversion, demodulation processing, and decoding as needed on the control channel of the different system received by the F unit 614.

Intra-frame control channel read controller 616
Receives the notification from the error detection unit 609 that the error rate is equal to or less than the threshold value, and activates the intra-frame control channel reading unit 617. The intra-frame control channel reading unit 616 reads the control channel of the handover destination candidate demodulated from the demodulation processing unit 615 for a different system.

Next, the procedure for forming a demodulation free time will be described with reference to FIG. The antenna 601 is at least two antennas away from the base station.
A broadcast channel repeatedly transmitted at twice the rate is received. Next, in ST701, the first block stored in the first block data memory 606 is decoded by the block decoding unit 608.

In ST702, error detecting section 609 performs error detection on the decoded first block. If the error rate is equal to or more than the threshold, the process proceeds to ST703, and if it is equal to or less than the threshold, the process proceeds to ST704.

In ST 703, block data memory storage control section 607 having been instructed that the error rate is equal to or greater than the threshold value, converts the data of the second block during or after demodulation in RAKE combining / demodulating section 605. The data is stored in the second block data memory 606. Then, the first adder 611 stores the data stored in the first block data memory 606 and the data stored in the second block data memory 6.
The data stored in 06 is added and stored in the first block addition data memory 612. Addition control unit 61
“0” sends the addition result stored in the first block addition data memory 612 to the block decoding unit 608.

When the processing of ST703 is completed, S
Returning to T701, the first block addition data memory 2
12 is decoded by the block decoding unit 208, and the process proceeds to ST702 to perform error detection. If the error rate is equal to or greater than the threshold, the process proceeds to ST703 again, and if the error rate is equal to or less than the threshold, the process proceeds to ST704.

Steps ST701 to ST703 are repeated until the error rate becomes equal to or less than the threshold value. ST after the second time
In 703, the block data memory storage controller 6
07 stores the data of the next block (x-th block) during or after demodulation in the RAKE combining / demodulating unit 605 in the x-th block data memory 606. Then, the x-th adder 610 adds the data of the (x−1) -th block addition memory 612 to the (x + 1) -th block data memory 606 and stores the result in the x-th block addition memory 612. The addition control unit 611 sends the addition result stored in the first block addition data memory 612 to the block decoding unit 608.

In ST 704, it is determined that the necessary data for one frame of the broadcast channel has been received, and the reception of the broadcast channel is stopped. That is, R that receives a notification from the error detection unit 609 that the error rate is equal to or less than the threshold value
The xRF unit selection control unit 613 switches the RxRF switching unit 602 to operate the RxRF unit 614 for a different system. Therefore, the remaining time until one frame time elapses is secured as a free time, and the carrier control of the handover destination candidate is monitored.

Here, for example, when the error rate is equal to or less than the threshold value when the head block is decoded and the RxRF unit is switched, the RxRF unit 603 receives the head block from the reception of the head block until the RxRF unit is switched. The broadcast channel data is discarded when the error detection unit 609 outputs a result indicating that there is no error.

As described above, since the transmitting / receiving device on the side of the base station communication device repeatedly transmits a block in which broadcast channel information for one frame is compressed in one frame, the transmitting / receiving device on the side of the communication terminal device that receives this is most likely. 1 if less
Information for one frame can be obtained only by receiving a block. By stopping reception of the broadcast channel when it is confirmed that information for one frame of the broadcast channel has been obtained, the remaining time until one frame time elapses can be set as the idle time for demodulation. Therefore, error detection is performed block by block. If the error rate is below the threshold, reception is stopped. If the error rate is above the threshold, the next block having the same information is added, and the error rate is below the threshold. Blocks are successively received and added until.

In this way, the reception of information for one frame can be completed in as few blocks as possible, that is, as short as possible, and the remaining time in one frame can be reserved for cell search as a demodulation idle time.

Next, a case where transmission power control is performed using a broadcast channel in the wireless communication system of the present invention will be described. FIG. 8 is an example of a transmission / reception slot configuration used in the wireless communication system according to the embodiment. In FIG. 8, as an example, one frame is divided into four as in FIG.
The figure shows a case where the image is divided into one subframe. With reference to this figure, uplink open-loop transmission power control and base station transmission diversity at the time of public service will be described.

In the downlink, the base station communication apparatus transmits a broadcast channel 806 to all users at a timing corresponding to the last downlink slot of the subframe. Here, paying attention to user # 1, the broadcast channel 806 is also transmitted in the assigned downlink slot 805 before the four slots 801, 802, 803, and 804. Therefore, by monitoring the broadcast channel, specifically, by measuring the reception power of the symbol data transmitted on the broadcast channel, it is possible to grasp the immediately preceding propagation path condition. Therefore, T
The open loop transmission power control can be performed in the uplink slot 801 even when the space between the downlink slot and the next uplink slot is wide due to the DMA structure.

The signal transmitted in uplink slot 801 includes a TPC bit for downlink SIR type closed loop transmission power control. On the other hand, in downlink slots 802, 803, and 804, closed-loop transmission power control is performed by demodulating the TPC bits transmitted in uplink slot 801. As a result, even when the fading fluctuation is fast, it is possible to sufficiently follow both the uplink and the downlink, and the performance of the system is improved.

In consideration of transmission diversity in the base station communication apparatus, it is desirable that the first (first) slot in the subframe is used for the uplink and the last (fourth) slot is used for the downlink. This is because in order for the base station communication apparatus to perform transmission diversity on the downlink, an uplink slot from a user using the subframe immediately before is required. Therefore, by using the first slot in the uplink and the fourth slot in the downlink, the communication terminal apparatus can perform transmission power control using a broadcast channel, and the base station communication apparatus can receive a signal from the communication terminal apparatus. And transmission diversity using the.

[0087]

As described above, according to the present invention, the TDMA
In CDMA / TDD having a structure, it is possible to suppress inter-system interference at the time of home service and to make the frame structure common to public and home services. Also, uplink open loop transmission power control and base station transmission diversity can be applied.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication terminal device in a wireless communication system according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a base station communication device in the wireless communication system according to the embodiment.

FIG. 3 is a frame diagram showing a transmission / reception slot configuration pattern used in the wireless communication system according to the embodiment.

FIG. 4 is a frame diagram showing a transmission / reception slot configuration and a broadcast channel structure used in a public service in the wireless communication system according to the embodiment.

FIG. 5 is a frame diagram showing a transmission / reception slot configuration and a broadcast channel structure used in a home service in the wireless communication system according to the embodiment.

FIG. 6 is a block diagram showing a main part of the communication terminal device according to the embodiment.

FIG. 7 is a flowchart for explaining a demodulation idle time forming process according to the embodiment.

FIG. 8 is a diagram for explaining operations of uplink open-loop transmission power control and base station transmission diversity in the wireless communication system according to the above embodiment.

FIG. 9 is a frame diagram showing a broadcast channel structure conventionally used;

[Explanation of symbols]

 Reference Signs List 102 CDMA demodulator for communication channel 103 CDMA demodulator for control channel 104 reception slot control unit 105 reception signal strength measurement unit 106 SIR measurement unit 111, 207 transmission power control unit 112 transmission / reception slot control unit 203 antenna reception power comparator 208 Antenna selection control section 211 CDMA modulator for broadcast channel

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04L 5/16 H04J 13/00 G (72) Inventor Kazuyuki Miya 3-1, Tsunashimahigashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Matsushita Communication Industrial Co., Ltd. Inside the company (72) Inventor Mitsuru Uesugi 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. (72) Inventor Osamu Kato 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Matsushita Communication Industrial Co., Ltd.

Claims (17)

[Claims] 1. A communication control means for communicating with a base station communication apparatus in a CDMA / TDD system using a signal frame-structured in a TDMA structure including a sub-frame formed of a plurality of time slots, and And a demodulating means for demodulating only a broadcast channel signal received at a timing corresponding to a last downlink time slot. 2. The communication terminal apparatus according to claim 1, wherein the broadcast channel signals include the same data, and the demodulation unit obtains demodulated data by combining the broadcast channel signals for a unit frame. . 3. An error detecting means for detecting a code error of the broadcast channel signal, and a demodulation stop instruction means for instructing the demodulation means to stop demodulation in accordance with the error detection result. The communication terminal device according to claim 1. 4. The demodulation stop instructing means instructs the demodulation means to stop demodulation of a broadcast channel signal received thereafter when an error detection result is good. 3. The communication terminal device according to 3. 5. The communication terminal according to claim 4, wherein said demodulation means demodulates another broadcast channel signal after receiving an instruction from said demodulation stop instruction means to stop demodulation of a broadcast channel signal. apparatus. 6. The communication terminal apparatus according to claim 1, wherein said demodulating means demodulates only a system-specific broadcast channel signal which is a last downlink broadcast channel signal in said subframe. 7. The system according to claim 1, wherein said communication control means operates in a system in which a first time slot in a subframe is used in an uplink and a last time slot is used in a downlink. 6. The communication terminal device according to any one of 5. 8. The communication terminal device according to claim 7, wherein the frame includes a subframe having a different slot configuration other than the first and last time slots. 9. A quality measuring means for measuring the quality of a broadcast channel signal received immediately before a first time slot in the subframe, and an uplink transmission power control means for controlling uplink transmission power based on the measurement result. The communication terminal device according to any one of claims 1 to 8, comprising: 10. A communication control means for communicating with a communication terminal device in a CDMA / TDD system using a signal frame-structured in a TDMA structure including a sub-frame formed by a plurality of time slots, A transmission control means for transmitting a broadcast channel signal only at a timing corresponding to a downlink time slot. 11. The base station according to claim 10, wherein said transmission control means performs control for transmitting a system-specific broadcast channel signal at a timing corresponding to a last downlink time slot in said subframe. Station communication equipment. 12. The transmission control means operates in a system in which a first time slot in a subframe is used in an uplink and a last time slot is used in a downlink. 12. The base station communication device according to 11. 13. TPC information acquisition means for acquiring TPC information generated by a communication terminal device based on the quality of the broadcast channel signal from an uplink communication channel signal, and downlink transmission power based on the TPC information. 13. The base station communication apparatus according to claim 10, further comprising a transmission power control unit for performing control. 14. A wireless communication system comprising: the communication terminal device according to claim 1; and a base station communication device that performs wireless communication with the communication terminal device. . 15. A wireless communication system comprising: the base station communication device according to any one of claims 10 to 14; and a communication terminal device that performs wireless communication with the base station communication device. system. 16. The base station communication apparatus according to claim 1, wherein said base station communication apparatus only has a timing corresponding to the last downlink time slot in said subframe of a communication channel signal framed in a TDMA structure including a subframe formed of a plurality of time slots. A wireless communication method, comprising: transmitting a broadcast channel signal; a communication terminal receiving the broadcast channel signal at the timing; and demodulating the broadcast channel signal. 17. A step of detecting a code error of the broadcast channel signal, and instructing the demodulation means to stop demodulation of a subsequently received broadcast channel signal when the error detection result is good. 17. The wireless communication method according to claim 16, comprising: