JP4612948B2 - Wireless communication terminal and wireless communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio communication terminal and a radio communication system that can change a transmission rate according to a line capacity and communication quality.
[0002]
[Prior art]
In recent years, high-speed and high-quality data transmission such as transmission of still images and moving images, browsing of the Internet, and the like has been demanded for mobile communication. Therefore, a variable spreading called third generation (IMT-2000), compared to a conventional CDMA mobile communication system that performs CDMA transmission with a fixed spreading factor (fixed transmission rate), that is, all mobile stations and all base stations have the same spreading factor. A CDMA mobile communication system that performs rate transmission has been proposed. The variable spreading factor transmission is a large spreading factor when transmitting low-speed data such as voice, that is, a low transmission rate, and a small spreading factor when transmitting high-speed data such as images. That is, transmission is performed at a high transmission rate.
[0003]
As an example of making the transmission rate variable, for example, according to the wireless communication device and the transmission rate control method disclosed in Japanese Patent Laid-Open No. 2000-49663, the communication terminal device measures the reception quality, and the measurement result is the base station device. To report to. The base station apparatus switches the transmission rate based on the reception quality report result. That is, the transmission rate is switched starting from the time when the reception quality of the communication terminal apparatus deteriorates. Further, the transmission rate is switched so as to be within a range where the amount of interference with others can be allowed according to the communication path state between the communication terminal apparatus and the base station apparatus.
[0004]
[Problems to be solved by the invention]
However, in the conventional wireless communication terminal, the user cannot desire the transmission rate and communication quality. Also, if data transmission is performed at a transmission rate and communication quality desired by the user, the line efficiency deteriorates by concentrating on a specific transmission rate and communication quality.
[0005]
The present invention has been made in view of the above-described problems, and can select a transmission rate and communication quality desired by a user. An optimum transmission rate and communication quality at the start of communication or during communication can be selected by a base station or Provided is a radio communication terminal and a radio communication system that can reduce an increase in interference of other radio communication terminals in the same cell and prevent an excess of line capacity in the cell in advance by determining the radio communication terminal The purpose is to do.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, a wireless communication terminal according to the present invention estimates a channel state, and a wireless communication terminal in which a base station or a wireless communication terminal changes a transmission rate and required quality according to a result of the estimation. The user requests the transmission rate and the required quality.
[0007]
According to such a configuration, the transmission rate and required quality desired by the user can be selected.
[0008]
In the wireless communication terminal according to the present invention, whether the request can be made or not is determined with respect to the line status, and a result of the determination is notified to the user.
[0009]
According to such a configuration, it is possible to know whether or not the transmission rate and required quality desired by the user can be received.
[0010]
A wireless communication system according to the present invention includes the above-described wireless communication terminal and a base station that communicates with the wireless communication terminal.
[0011]
According to such a configuration, the transmission rate and required quality desired by the user can be selected, and it can be known whether or not the desired transmission rate and required quality can be received.
[0012]
The radio communication system according to the present invention is characterized in that the transmission rate and the required quality are changed when there is a margin in the line status.
[0013]
With such a configuration, the base station or the wireless communication terminal determines the optimum transmission rate and communication quality during communication, so that the line efficiency is improved.
[0014]
Further, in the wireless communication system according to the present invention, the base station or the wireless communication terminal determines whether or not the request can be made, and if the result of the determination is impossible, the transmission rate and the required quality are changed. It is characterized by this.
[0015]
According to such a configuration, the base station or the wireless communication terminal determines the optimum transmission rate and communication quality at the start of communication, so that it is possible to prevent the channel capacity in the same cell from being exceeded in advance.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration example of a mobile station in the radio communication system according to the present embodiment. Here, the mobile station is a wireless communication terminal. Hereinafter, the configuration and operation of the present embodiment will be described with reference to FIG. First, the mobile station receives a broadcast channel from the base station. The broadcast channel signal spread by the base station is subjected to despreading processing in the demodulation portion of the CDMA modem 101 and converted to a broadcast channel primary modulation signal. The broadcast channel primary modulation signal is output to broadcast channel demodulation section 102, broadcast channel received power measurement section 103, and interference wave power measurement section 104. The broadcast channel primary modulation signal is demodulated as broadcast information by the broadcast channel demodulation unit 102, and the downlink total transmission power allowable maximum value, the downlink total transmission power value, and the downlink broadcast channel transmission power value are extracted from the broadcast information. The maximum allowable total transmission power value and the total downlink transmission power value are output to the reception availability determination unit 108, and the downlink broadcast channel transmission power value is output to the propagation loss estimation unit 105.
[0017]
Here, the downlink maximum allowable transmission power maximum value indicates the maximum value of the transmission power preset in the system for the transmission source base station. The downlink total transmission power value indicates the sum of the transmission powers of the channels currently transmitted by the transmission source base station. The downlink broadcast channel transmission power value indicates the transmission power of the broadcast channel alone that is currently transmitted by the transmission source base station.
[0018]
On the other hand, the broadcast channel received power included in the broadcast channel primary modulation signal is measured by broadcast channel received power measuring section 103, and this received power is output to propagation loss estimating section 105 as a downlink broadcast channel received power value. The measured downlink broadcast channel reception power value and the downlink broadcast channel transmission power value included in the broadcast information are calculated by the propagation loss estimation unit 105, and this result is output to the required transmission power estimation unit 107 as a propagation loss. . An arithmetic expression (1) is shown below.
[0019]
Propagation loss = downlink broadcast channel transmission power value-downlink broadcast channel reception power value (1)
[0020]
The interference wave power included in the broadcast channel primary modulation signal is measured by the interference wave power measurement unit 104 and output to the reception required power estimation unit 106 as an interference wave power value.
[0021]
Next, the operation of the required reception power estimation unit 106 will be described. The required reception power estimation unit 106 represents the type of data that the mobile station wants to receive as a parameter. Here, the parameters are transmission spreading factor and required quality. The required reception power estimation unit 106 estimates the required reception power before despreading of the mobile station, that is, at the receiver input end using the interference wave power value in order to satisfy the transmission spreading factor and the required quality, and the result is obtained. This is output to the required transmission power estimation unit 107 as the required reception power value.
[0022]
As a specific example, the required quality is BER (bit error rate) = 1 × 10.^-6A case where it is desired to receive the image data will be described. The mobile station has the required quality BER = 1 × 10^-6Required E to get_b/ I₀(Signal energy per bit versus energy of interference wave power) is obtained. This is a receiver-specific E_b/ I₀This can be easily realized by preliminarily holding the curve of the BER characteristic as a table in a memory or the like. Temporarily, required quality BER = 1 × 10^-6Required E to get_b/ I₀= 15 (dB). Further, it is assumed that the interference wave power value measured by the interference wave power measuring unit 104 is −100 (dBm). E_b/ I₀= 15 (dB), interference power value = -100 (dBm), reception power R required after despreading_de-spreadCan be expressed by the following equation (2).
[0023]
R_de-spread= Interference wave power value + Required E_b/ I₀  (2)
= -100 + 15 = -85 (dBm)
[0024]
Also, the required power value for reception is R_inThen R_inDepends on the assumed transmission spreading factor PG (dB) and can be expressed by the following equation (3).
[0025]
R_in= R_de-spread-PG (3)
[0026]
Assuming that PG = 21 (dB), from equation (3), R_in= −85-21 = −106 (dBm). FIG. 2 shows the required E as in the above example._b/ I₀10 is a table showing an example of a transmission spreading factor and a required reception power value for a communication type calculated when = 15 (dB) and interference wave power value = −100 (dBm).
[0027]
Next, the operation of the required transmission power estimation unit 107 will be described. The required transmission power estimation unit 107 determines the base necessary to satisfy the required quality and the transmission spreading factor from the reception required power value estimated by the reception required power estimation unit 106 and the propagation loss estimated by the propagation loss estimation unit 105. The transmission power of the station is estimated, and the result is output to the reception availability determination unit 108 as a required transmission power value. Required transmission power value T_outCan be expressed by the following equation (4).
[0028]
T_out= R_in+ Propagation loss (4)
[0029]
It is assumed that the propagation loss estimated by the propagation loss estimation unit 105 is 20 (dB). FIG. 3 is a table showing an example of the required transmission power value calculated based on FIG. 2 when propagation loss = 20 (dB).
[0030]
Next, the operation of the reception availability determination unit 108 will be described. The reception permission / non-permission determining unit 108 transmits, to the base station, the remaining transmission power value estimated by the transmission required power estimation unit 107 and the downlink total allowable transmission power allowable maximum value and the downlink total transmission power value included in the broadcast information. Is output to the display unit 109 and the switch unit 111 as reception availability.
[0031]
As a specific example, it is assumed that the downlink total transmission power allowable maximum value = −70 (dBm) and the downlink total transmission power value = −75 (dBm). First, when the mobile station performs transmission of number 1 in FIG. 3, the required transmission power value becomes −89 (dBm) from number 1 in FIG. 3. By adding power to the total downlink transmission power value and the required transmission power value, the expected total downlink transmission power value of the base station can be obtained as follows.
[0032]
Expected total downlink transmission power value = total downlink transmission power value + required transmission power value
= −75 (dBm) + (− 89 (dBm))
≒ -74.8 (dBm) <-70 (dBm)
[0033]
Therefore, since the expected downlink total transmission power value does not exceed the maximum allowable downlink total transmission power value, it is determined that the transmission of number 1 in FIG. 3 can be received.
[0034]
When the mobile station performs transmission of number 7 in FIG. 3, the required transmission power value is −71 dBm from number 7 in FIG. 3. By adding power to the total downlink transmission power value and the required transmission power value, the expected total downlink transmission power value of the base station can be obtained as follows.
[0035]
Expected total downlink transmission power value = total downlink transmission power value + required transmission power value
= −75 (dBm) + (− 71 (dBm))
≈-69.5 (dbm)>-70 (dBm)
[0036]
Therefore, since the expected total downlink transmission power value exceeds the maximum downlink total transmission power allowable value, it is determined that transmission of number 7 in FIG. 3 cannot be received.
[0037]
The reception availability of the reception availability determination unit 108 is output to the display unit 109 to clearly indicate to the user of the mobile station at which transmission spreading rate transmission is possible. Further, the display unit 109 can display the result of estimating how much the base station is capable of transmitting, in addition to whether or not reception is possible, as the line state in the cell where the mobile station is located.
[0038]
When the user selects what number of transmission in FIG. 3 by the operation unit 110 based on the reception availability displayed on the display unit 109, the selected transmission spreading factor and quality information are generated by the operation unit 110. In addition, the mobile station always selects the selected transmission spreading factor and quality information determined and determined to be optimum by the reception availability determining unit 108, negotiates with the base station during communication, and adaptively changes the selected transmission spreading factor while changing the data. Can be received and demodulated.
[0039]
Furthermore, it is also possible to switch the selected transmission spreading factor and quality information selected by the user in the operation unit 110 and the selected transmission spreading factor and quality information determined to be optimal by the reception availability determination unit 108 by the switch unit 111. is there. As a result, the selected transmission spreading factor and quality information generated are output to transmission information generating section 112.
[0040]
The selected transmission spreading factor and quality information for requesting to the base station what kind of quality data the mobile station is going to receive at what transmission spreading factor are input from the outside by the transmission information generator 112. Multiplexing and frame format are performed together with the transmission data, and CDMA modulation is performed by the modulation part of the CDMA modem unit 101 and transmitted to the base station. Upon receiving the request, the base station opens a communication channel with the requested transmission spreading factor and quality, and starts downlink transmission toward the requested mobile station. The communication channel received by the mobile station is subjected to despreading processing using the requested transmission spreading factor in the demodulation part of the CDMA modem 101, and the communication channel demodulator 113 demodulates the communication channel to obtain communication data. Is output to the display unit 109.
[0041]
According to the above-described wireless communication system, it is possible to clearly indicate to the user at which transmission spreading rate transmission is possible, and it is possible to prevent transmission that causes inadvertent excess of line capacity or increase in interference. It becomes possible.
[0042]
Next, a communication line status display method will be described with reference to FIG. FIG. 4 is a diagram showing an example of display on the display unit 109 when the user selects the selected transmission spreading factor and quality information. Display example 1 shows a case where the communication line status is good. This display indicates that there is a sufficient line capacity, that is, the number of users is low, or low-rate and low-quality services are being performed. At this time, the user can receive a high level of service regarding the transmission speed and communication quality. The user selects a desired communication type based on the displayed communication line status, and inputs the selected communication type number on the operation unit 110. Data transmission is represented in three stages of A, B, and C in descending order of transmission level and communication quality. For example, the communication type No. 1 represents a service whose transmission speed and communication quality are both level A.
[0043]
Display example 2 shows a case where the communication line status is somewhat congested. This display indicates that the line capacity is slightly decreased, that is, one of the transmission speed and the communication quality is decreased. As in the case of display example 1, the user selects a desired communication type based on the displayed communication line status, and inputs the selected communication type number on the operation unit 110.
[0044]
Display example 3 shows a case where the communication line status is very congested. This display indicates that the line capacity has deteriorated, that is, both the transmission speed and the communication quality have decreased. As in the case of display example 1, the user selects a desired communication type based on the displayed communication line status, and inputs the selected communication type number on the operation unit 110.
[0045]
In the display example of FIG. 4, the transmission speed and communication quality are represented in three stages of A, B, and C, but may be represented with more stages. In addition, the transmission rate is represented by an actual value, for example, 384 kbps, 64 kbps, 32 kbps, and the communication quality is represented by an actual value, for example, BER = 1 × 10.^-6It may be expressed as
[0046]
Thus, by displaying the communication line status on the mobile station side, the user can know the current communication line status and can select the desired communication type. In addition, for example, by setting a low-level communication type at a low charge, the user is less likely to select a high-level communication type, so that congestion of communication lines can be prevented.
[0047]
Embodiment 2. FIG.
FIG. 5 is a block diagram showing a configuration example of a mobile station in the radio communication system according to the present embodiment. FIG. 6 is a block diagram showing a configuration example of a base station in the radio communication system according to the present embodiment. Hereinafter, the configuration and operation of the present embodiment will be described with reference to FIGS.
[0048]
First, the base station modulates the downlink broadcast channel transmission power value and other broadcast information as a broadcast channel by the broadcast channel modulation section 302, CDMA modulates by the modulation portion of the CDMA modulation / demodulation section 301, and transmits it to the mobile station.
[0049]
The mobile station receives a broadcast channel from the base station. The broadcast channel signal spread by the base station is subjected to despreading processing in the demodulating part of the CDMA modulation / demodulation unit 201 of the mobile station and converted into a broadcast channel primary modulation signal. The broadcast channel primary modulation signal is demodulated as broadcast information by the broadcast channel demodulation unit 202, and a downlink broadcast channel transmission power value is extracted from the broadcast information. The downlink broadcast channel transmission power value is output to propagation loss estimation section 205.
[0050]
On the other hand, the broadcast channel received power of the broadcast channel primary modulation signal is measured by broadcast channel received power measuring section 203, and this received power is output to propagation loss estimating section 205 as a downlink broadcast channel received power value. The measured downlink broadcast channel reception power value and the downlink broadcast channel transmission power value included in the broadcast information are calculated by propagation loss estimation section 205, and this result is output as propagation loss to uplink control channel modulation section 208. . The propagation loss is calculated from equation (1) using the downlink broadcast channel reception power value and the downlink broadcast channel transmission power value.
[0051]
Also, the interference wave power of the broadcast channel primary modulation signal is measured by the interference wave power measurement unit 204 and output to the uplink control channel modulation unit 208 as an interference wave power value.
[0052]
The possible communication type list 206 outputs to the desired communication type selection unit 207 and the uplink control channel modulation unit 208 all communication types that are held in advance as possible communication types, and the corresponding transmission spreading factor and required quality. When starting communication, the user selects a desired communication type from among possible communication types by key operation or the like. Here, the possible communication types are displayed on the display unit 211. The display method of the possible communication types is the same as the display method of the communication line status in the first embodiment. The desired communication type selection unit 207 outputs the transmission spreading factor and the required quality corresponding to the communication type desired by the user from the possible communication types to the uplink control channel modulation unit 208 as the desired communication type.
[0053]
The interference wave power value, propagation loss, desired communication type, and possible communication type, which are uplink control information, are modulated as a control channel by the uplink control channel modulation unit 208, CDMA modulated by the modulation part of the CDMA modulation / demodulation unit 201, and the control channel It is transmitted to the base station as a signal.
[0054]
The control channel signal received from the mobile station is demodulated by the CDMA modulation / demodulation unit 301 of the base station, demodulated as control information by the uplink control channel demodulation unit 303, and from the control information, the propagation loss, interference wave power value, mobile station desired communication type And mobile station-capable communication types are extracted. Here, the mobile station desired communication type is the desired communication type transmitted by the mobile station, and the mobile station-capable communication type is the possible communication type transmitted by the mobile station. Among these, the propagation loss, the interference wave power value, and the mobile station desired communication type are output to the compatible communication type determination unit 306. The mobile station-capable communication type is output to the possible communication type list 305 for each mobile station. The mobile station possible communication type is held in the possible communication type list 305 and is output to the compatible communication type determination unit 306.
[0055]
Here, the operation of the compatible communication type determination unit 306 will be described. The compatible communication type determination unit 306 includes a total downlink transmission power value from the transmission power estimation unit 304, a propagation loss and interference wave power value from the uplink control channel demodulation unit 303, a mobile station desired communication type, and a possibility for each mobile station. The mobile station-capable communication type from the communication type list 305 and the maximum downlink transmission power allowable maximum value preset in the system are input. Corresponding communication type determination unit 306 estimates how much the base station is capable of transmitting, and uses the corresponding communication type as a selected communication type, so that transmission power estimation unit 304, downlink control channel modulation unit 307, and communication channel modulation / demodulation To the unit 308.
[0056]
As a specific example, the required quality is BER = 1 × 10.^-6A case where the mobile station wants to receive the image data is described. Corresponding communication type determination unit 306 determines that the mobile station has the required quality BER = 1 × 10.^-6Required E to get_b/ I₀Ask for. This can be realized by holding and applying the reception capability of the mobile station determined in the system specifications in advance. Temporarily, required quality BER = 1 × 10^-6Required E to get_b/ I₀= 15 (dB). Further, it is assumed that the interference wave power value reported from the mobile station = −100 (dBm). E_b/ I₀= 15 (dB), interference power value = -100 (dBm), the received power R required after despreading in the mobile station_de-spreadIs represented by R (2)_de-spread= −100 + 15 = −85 (dBm).
[0057]
Further, the required power before despreading, that is, at the receiver input end, is calculated as the required reception power value R_inThen R_inDepends on the transmission spreading factor PG (dB) desired by the mobile station, and is calculated from equation (3). Assuming that PG = 21 (dB), from equation (3), R_in= −85-21 = −106 (dBm).
[0058]
Next, the compatible communication type determination unit 306 obtains a required transmission power value from the propagation loss and the required reception power value. The transmission required power value is the transmission power required by the base station for reception by the mobile station satisfying the transmission spreading factor and required quality indicated in the mobile station desired communication type. Required transmission power value T_outIs calculated from equation (4). Assuming that the propagation loss reported from the mobile station = 50 (dB), T_out= −106 + 50 = −56 (dBm).
[0059]
Next, the compatible communication type determination unit 306 estimates how much the base station is capable of transmitting from the required transmission power value, the maximum allowable downlink total transmission power value, and the total downlink transmission power value. As a specific example, it is assumed that the downlink total transmission power allowable maximum value = −30 (dBm) and the downlink total transmission power value = −40 (dBm). If communication of the desired communication type of the mobile station is performed, the expected total downlink transmission power value of the base station is obtained as follows.
[0060]
Expected total downlink transmission power value = total downlink transmission power value + required transmission power value
−40 (dBm) + (− 56 (dBm))
≒ -39 (dbm) <-30 (dBm)
[0061]
Therefore, since the expected total downlink transmission power value does not exceed the maximum allowable downlink total transmission power, the compatible communication type determination unit 306 determines that this mobile station desired communication type is compatible and outputs it as the selected communication type.
[0062]
As another specific example, the required quality is BER = 1 × 10.^-6A case where it is desired to receive the data will be described. Temporarily, required quality BER = 1 × 10^-6Required E to get_b/ I₀= 15 (dB). Further, it is assumed that the interference wave power value and the propagation loss reported from the mobile station are interference wave power value = −75 (dBm) and propagation loss = 50 (dB), respectively. Also assume that the downlink total transmission power allowable maximum value = −30 (dBm) and the downlink total transmission power value = −32 (dBm).
[0063]
From equation (2), R_de-spread= −75 + 15 = −60 (dBm). Required power value R_inIf PG = 21 (dB), from equation (3), R_in= −60−21 = −81 (dBm). The required transmission power value is calculated from T_out= −81 + 50 = −31 (dBm). Therefore, the expected total downlink transmission power value of the base station is obtained as follows.
[0064]
Expected total downlink transmission power value = total downlink transmission power value + required transmission power value
−32 (dBm) + (− 31 (dBm))
≒ -28 (dbm)> -30 (dBm)
[0065]
Since the expected total downlink transmission power value exceeds the maximum downlink total transmission power allowable maximum value, the compatible communication type determination unit 306 determines that the mobile station desired communication type from this mobile station is not compatible. If it is determined that the correspondence is not possible, the correspondence type determination unit 306 can select the next candidate communication type from the possible communication types of the mobile station in the possible communication type list 305 for each mobile station, and can cope with the method described above. Determine whether or not. Then, the communication type that can be handled is output as the selected communication type.
[0066]
The transmission power estimation unit 304 estimates the transmission power value for each code channel, such as the downlink broadcast channel transmission power value, from the power control information from the system and the selected communication type, and further adds all the transmission power values for each code channel. Estimate the total transmission power value. As a result, the downlink broadcast channel transmission power value is output to broadcast channel modulation section 302, and the total downlink transmission power value is output to compatible communication type determination section 306. Further, other radio parameters required by the mobile station when opening the communication channel with the selected communication type are modulated as a control channel by the downlink control channel modulation unit 307, CDMA modulated by the modulation part of the CDMA modulation / demodulation unit 301, and the control channel A signal is transmitted to the mobile station.
[0067]
The mobile station receives a control channel from the base station. The control channel signal spread by the base station is subjected to despreading processing in the demodulating part of the CDMA modulation / demodulation unit 201 of the mobile station, and converted into a control channel primary modulation signal. The control channel primary modulation signal is demodulated as control information by the downlink control channel demodulation unit 209, and the selected communication type and other radio parameters are extracted from the control information. The selected communication type and other radio parameters are output to the communication channel modulation / demodulation unit 210 and the display unit 211.
[0068]
The communication channel modulation / demodulation unit 210 of the mobile station opens a communication channel based on the selected communication type and other radio parameters. Communication channel transmission / reception data is exchanged between the CDMA modem unit 201 and the outside via the communication channel modem unit 210. The communication channel at the time of reception is demodulated by the CDMA modulation / demodulation unit 201, the communication channel modulation / demodulation unit 113 demodulates the communication channel, and is output to the display unit 211 as communication data. The communication channel at the time of transmission is modulated by the CDMA modem unit 201 and transmitted to the base station.
[0069]
On the other hand, the communication channel modulation / demodulation unit 308 of the base station opens a communication channel based on the selected communication type. Communication channel transmission / reception data is exchanged between the CDMA modem unit 301 and the outside via the communication channel modem unit 308. The communication channel at the time of reception is demodulated by the CDMA modem unit 301. Also, the communication channel at the time of transmission is modulated by the CDMA modem unit 301 and transmitted to the mobile station.
[0070]
Further, during communication, the line state is constantly monitored by the compatible communication type determination unit 207 of the base station. Here, a case where communication is performed using the selected communication type selected by the base station at the start of communication will be described as an example. When it is judged that the mobile station desired communication type desired by the mobile station is possible by disconnecting the line with other mobile stations, the selected communication type is changed, and the mobile station has a higher level. It is possible to communicate with the communication type.
[0071]
Conversely, a case where communication is performed using the mobile station desired communication type as the selected communication type at the start of communication is described as an example. When it is judged that the mobile station's desired communication type is not possible due to an increase in the number of other mobile stations that wish to communicate, and the mobile station's desired communication type is determined to be impossible, the level of the mobile station is reduced even if the communication type is changed. Therefore, the saturation of the line is prevented and the line capacity is used efficiently.
[0072]
【The invention's effect】
As described above in detail, according to the present invention, the transmission rate and communication quality desired by the user can be selected, and the optimum transmission rate and communication quality can be selected at the start of communication or during communication. Thus, it is possible to mitigate an increase in interference of other mobile stations in the same cell and prevent an excess of the line capacity in the same cell in advance. Also, by receiving and demodulating data while adaptively changing the transmission rate, for example, when interference is large, low-speed transmission is performed with a large spreading factor, and when interference is small, high-speed transmission is performed with a small spreading factor. For example, transmission according to the state of the line quality can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a mobile station in a radio communication system according to a first embodiment.
[Figure 2] Required E_b/ I₀10 is a table showing an example of a transmission spreading factor and a required reception power value for a data type calculated when = 15 (dB) and interference wave power value = −100 (dBm).
FIG. 3 is a table showing an example of required transmission power values calculated based on FIG. 2 when propagation loss = 20 (dB).
FIG. 4 is a diagram showing an example of display on the display unit 109 when a user selects a selected transmission spreading factor and quality information.
FIG. 5 is a block diagram showing a configuration example of a mobile station in the wireless communication system according to the second embodiment.
6 is a block diagram showing a configuration example of a base station in the radio communication system according to Embodiment 2. FIG.
[Explanation of symbols]
101, 201, 301 CDMA modulation / demodulation unit, 102, 202 broadcast channel demodulation unit, 103, 203 broadcast channel reception power measurement unit, 104, 204 interference power measurement unit, 105, 205 propagation loss estimation unit, 106 required reception power estimation unit, 107 Required transmission power estimation unit, 108 Receivability determination unit, 109, 211 Display unit, 110 Operation unit, 111 Switch unit, 112 Transmission information generation unit, 113 Communication channel demodulation unit, 206 Possible communication type list, 207 Desired communication type selection 208, uplink control channel modulation unit, 209 control channel demodulation unit, 210, 308 communication channel modulation / demodulation unit, 302 broadcast channel modulation unit, 303 uplink control channel demodulation unit, 304 transmission power estimation unit, 305 Possible communication types for each mobile station List, 306 Applicable communication type determination unit, 30 7 Downlink control channel modulator.

Claims (5)

In a wireless communication terminal used in a wireless communication system that performs communication by changing the transmission rate and required quality between the base station and the wireless communication terminal according to the estimation result, estimating the channel status
Means for a user to request the transmission rate and the required quality;
A display unit for displaying the line status and possible communication types;
An operation unit for selecting the transmission rate and the required quality corresponding to a desired communication type based on the displayed line status and the possible communication type;
A wireless communication terminal comprising: The wireless communication terminal according to claim 1,
At the start of the communication, a desired communication type selection unit is provided that transmits a transmission spreading factor and required quality corresponding to a communication type desired by a user from the possible communication types as a desired communication type to the base station. A wireless communication terminal.   A radio communication system comprising the radio communication terminal according to claim 1 and the base station that communicates with the radio communication terminal. The wireless communication system according to claim 3,
If it is determined that the mobile station desired communication type from the mobile station that is the wireless communication terminal is not compatible,
The compatible communication type determination unit selects the next candidate communication type from the mobile station-capable communication types for each mobile station, determines whether or not it can be supported, and sets the corresponding communication type as the selected communication type to the mobile station. A wireless communication system characterized by transmitting. The wireless communication system according to claim 3,
A wireless communication system, wherein the transmission rate and the required quality are changed when it is determined that a margin has occurred in the channel status based on the estimation result of the channel status.

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