WO2008004299A1 - Wireless communication system, base station apparatus and mobile station apparatus - Google Patents

Abstract

A wireless communication system, a mobile station apparatus and a base station apparatus wherein the frequency use efficiency is improved and a high speed mobile communication can be achieved. This wireless communication system comprises mobile and base stations and uses a plurality of communication channels and pilot channels associated with those respective communication channels to establish wireless communication between the mobile and base stations. The base station has a power control means that uses, as a priority channel, at least one of the plurality of communication channels and that sets the transmission power of a pilot channel associated with the priority channel to be higher than the transmission powers of the pilot channels associated with the other communication channels. The mobile station comprises a determining means that determines a reception level of a pilot channel transmitted from the base station; and a deciding means that decides, in accordance with the reception level, at least one of the plurality of communication channels as an available communication channel.

Description

 Specification

 Wireless communication system, base station apparatus, and mobile station apparatus

 Technical field

 [0001] The present invention relates to a radio communication system, a base station apparatus, and a mobile station apparatus that perform channel allocation control.

 Background art

 [0002] In mobile communication systems, a third-generation mobile phone system using a CDMA (Code Division Multiple Access) system has been put into practical use, and in recent years, higher-speed communication has become possible. A generation mobile communication system is being studied! /, (See Non-Patent Document 1 below). For this next-generation mobile communication system, the application of the OFDM (Orthogonal Frequency Division Multiplexing) system is being considered instead of the CDMA system. The OFDM scheme is a scheme in which transmission data is divided into a plurality of pieces, and the divided transmission data is mapped to a plurality of orthogonal carriers (subcarriers) and transmitted in parallel on the frequency axis.

 [0003] In such a mobile communication system using the OFDM scheme, it is necessary to assign different frequency bands to adjacent base stations. This is because if adjacent base stations perform radio communication using the same frequency band, interference will occur between them. However, in order to increase the frequency utilization efficiency, it is desirable that each base station can use the same frequency band as much as possible.

 [0004] On the other hand, a method has been proposed in which the frequency repetition distance is made variable in accordance with the distance of the base station of the mobile station (see Non-Patent Document 2 below). This frequency repetition distance is the distance (number of cells) required for each base station (cell) when considering an arrangement in which adjacent base stations do not use the same frequency band. In this method, when the mobile station is at a position far from the base station power, the repeat distance is increased (for example, repeat distance 3) to prevent interference with the adjacent base station, and when the mobile station is at a position close to the base station power. For example, by reducing the repetition distance (for example, repetition distance 1, that is, all frequency channels can be used), the frequency utilization efficiency is improved.

Special Reference 1: Technical Specincation uroup Radio Access Network, Requirements for Evolved UTRA (E— UTRA) and Evolved UTRAN (E— UTRAN) (Release 7) ", 3rd Generation Partnership Project, 3GPP TR 25.913 V7.2.0, December 2005

 Non-Patent Document 2: Samsung, "Flexible Fractional Frequency Reuse Appro", 3rd Generati on Partnership Project TSG— RAN WG1, Rl— 051341, 8.2, November 2005 Invention Disclosure

 Problems to be solved by the invention

However, a specific method for applying the above-described method for changing the frequency repetition distance to a mobile communication system has not been proposed and has been a problem.

An object of the present invention is to provide a radio communication system, a mobile station apparatus, and a base station apparatus that realize high-speed mobile communication while improving frequency utilization efficiency.

 Means for solving the problem

The present invention adopts the following configuration in order to solve the above-described problems. That is, according to the present invention, a base station apparatus that wirelessly communicates with a mobile station using a plurality of communication channels and pilot channels corresponding to each communication channel uses at least one of the plurality of communication channels as a priority channel. Power control means is provided for setting the transmission power of the pilot channel corresponding to the priority channel higher than the transmission power of the pilot channel corresponding to the other communication channels.

 [0008] According to the present invention, a mobile station that receives a signal transmitted from a base station apparatus may or may not be able to receive all of the nolot signals depending on its position. In other cases, for example, only a pilot signal with a high transmission power is received, or another pilot signal with a low reception level is received together with the pilot signal.

 [0009] Thereby, the mobile station can determine an available communication channel by detecting the pilot signal.

[0010] That is, the present invention provides a measuring means for measuring a reception level of a pilot channel that also transmits the base station apparatus power as described above, and the plurality of communication channels used by the base station apparatus according to the reception level. And a determining means for determining at least one of the communication channels as an available communication channel. [0011] For example, the determination unit determines a communication channel corresponding to a pilot channel having a reception level larger than a predetermined threshold among the reception levels measured by the measurement unit as an available communication channel.

 [0012] Also, the mobile station apparatus according to the present invention may further include transmission means for generating channel information related to the usable communication channel determined as described above and transmitting the channel information to the base station. Good.

 [0013] Thereby, the base station apparatus according to the present invention transmits the data addressed to the mobile station through the communication channel corresponding to the channel information transmitted from the mobile station among the plurality of communication channels. A selection means for selecting as a communication channel to be used may be further provided.

 With this configuration, the base station apparatus according to the present invention can recognize communication channels that can be used by each mobile station based on channel information transmitted from each mobile station. it can. For example, a communication channel for which channel information is not sent may be recognized as a channel that is not usable for the mobile station device.

 Here, the above-described channel information may be, for example, information based on CQI (Channel Quality Indicator) information or other channel estimation values, and is an identification for identifying an available communication channel. It may be information.

 [0016] Thus, according to the present invention, the mobile station apparatus can determine an appropriate available channel according to its location by measuring the reception level of the pilot channel. As a result, even if the same plurality of communication channels are assigned to each adjacent base station apparatus, the mobile station apparatus determines an available channel that does not cause interference, thereby maintaining high communication quality. However, high frequency utilization efficiency can be achieved.

[0017] Note that the present invention may relate to a mobile communication system having the above mobile station apparatus and base station apparatus. Further, the present invention may be a method for causing a computer to realize any one of the functions described above. Further, the present invention may be a program or a circuit for realizing any of the functions described above. Further, the present invention may be a program in which such a program is recorded on a computer-readable storage medium. The invention's effect

 [0018] According to the present invention, it is possible to provide a radio communication system, a mobile station apparatus, and a base station apparatus that realize high-speed mobile communication while improving frequency utilization efficiency.

 Brief Description of Drawings

 FIG. 1 is a diagram showing a system configuration of a wireless communication system in the present embodiment.

 FIG. 2 is a block diagram showing an outline of a functional configuration of the base station apparatus.

 FIG. 3 is a diagram showing an example of a radio frame format of an OFDM signal.

 [FIG. 4] FIG. 4 is a diagram showing transmission power of pilot channels Pl, P2 and P3 in base station BS1.

 FIG. 5 is a diagram showing transmission power of pilot channels Pl, P2 and P3 in base station BS2.

 FIG. 6 is a diagram conceptually showing an example of the relationship between pilot channel transmission power and available channels of a mobile station in the wireless communication system of the present embodiment.

 FIG. 7 is a block diagram showing an outline of a functional configuration of a communication terminal apparatus.

 Explanation of symbols

[0020] MS1, MS2 communication terminal equipment (mobile station)

 BS1, BS2 Base station equipment (base station)

 101, 201 antenna

 120 Transmitter

 110 Receiver

 111, 202 receiver

 113 Response information collection unit

 121, 203 transmitter

 122 Pilot data generator

 123 Broadcast information generator

 127 Scheduler

 129, 129—1, 129—2,..., 129—n Neuro data storage unit

124, 210 Control unit 125 Synthesizer

 205 Pilot judgment part

 207 Response information generator

 208 Data processor

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, a radio communication system according to an embodiment of the present invention will be described with reference to the drawings. The configuration of each of the following embodiments is an exemplification, and the present invention is not limited to the configuration of each of the following embodiments.

 [0022] [Embodiment]

 Hereinafter, a radio communication system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a system configuration of a wireless communication system in the present embodiment. The radio communication system in the present embodiment includes base station apparatuses BS1 and BS2 (hereinafter also simply referred to as base stations), mobile communication exchange station apparatuses (not shown) that perform exchange control of signals received at these base stations, etc. Etc. The radio communication system in the present embodiment performs predetermined communication with communication terminal devices MS1 and MS2 (hereinafter simply referred to as mobile stations) connected to the radio communication system by performing radio communication with base stations BS1 and BS2. Provide communication services. Note that base station apparatuses BS1 and BS2 are adjacent to each other.

 [0023] It is assumed that channels CH1, CH2, and CH3 are assigned to the base station devices BS1 and BS2 for communication, respectively. Furthermore, one of the communication channels is assigned as a priority channel so that the base station apparatuses BS1 and BS2 are different from each other. In this embodiment, channel CH1 is assigned as a priority channel to base station BS1, and channel CH2 is assigned as a priority channel to base station BS2. The priority channel is a communication channel that can be preferentially used in the base station. In the present invention, the number of priority channels is not limited. For example, the priority channels of the base station BS2 may be channels CH2 and CH3.

[0024] Reference numerals 1 and 2 shown in FIG. 1 indicate communication areas (cells) of the base stations BS1 and BS2, respectively. In the following description, as shown in FIG. 1, the mobile station MS 1 is far from the base station. The case where the mobile station MS2 exists at a location and is close to the base station will be described as an example. Note that the base stations BS1 and BS2 have functional units related to the present invention described below, and the same applies to the mobile stations MS1 and MS2. The base station devices (BS1 and BS2) and communication terminal devices (MS1 and MS2) will be described below.

[Base station apparatus]

 First, an outline of the functional configuration of the base station devices (BS1 and BS2) will be described with reference to FIG. FIG. 2 is a block diagram showing an outline of a functional configuration of the base station apparatus. As shown in FIG. 2, the base station apparatus is generally composed of an antenna 101, a transmission unit 120, and a reception unit 110.

 [0026] Transmitting section 120 receives data to be transmitted (transmission data) and control information from other functional sections (not shown), and receives these data as radio signals using communication channels assigned to each base station. Transmit from antenna 101. The receiving unit 110 receives signals received by the antenna 101, demodulates and decodes control information and received data from these signals, and sends the obtained data to another functional unit (not shown).

 Each of these functional units may be realized by a nodeware circuit, and is realized by loading a control program stored in the memory into a CPU (Central Processing Unit) and executing it. You may make it do. In FIG. 2, only functional parts related to the present invention are shown.

 [0028] <Receiving unit>

 The reception unit 110 includes a receiver 111, a response information collection unit 113, and the like. The receiver 111 performs processing such as analog Z digital conversion, demodulation, and decoding on the radio signal received by the antenna 101 to obtain control information and received data (user data). The receiving unit 110 passes the obtained control information to the response information collecting unit 113.

[0029] This control information includes downlink channel information generated by the mobile station (base station power is also directed to the mobile station). In this embodiment, CQI (Channel Quality Indicator) information is used as the channel information. Note that this embodiment does not limit the types of such channel information. Also, this CQI information is generated for each communication channel of the received signal in the mobile station, and corresponds to each communication channel. Information is sent to the base station. This CQI information generation method will be described later.

[0030] Response information collection section 113 acquires CQI information from the control information passed from receiver 111. The response information collection unit 113 passes CQI information associated with each communication channel to the scheduler 127 of the transmission unit 120.

<Transmitter>

 The transmission unit 120 includes a transmitter 121, a pilot data generation unit 122, a broadcast information generation unit 123, a scheduler 127, and the like.

 [0032] The transmitter 121 includes a serial Z-parallel conversion unit, a modulation unit, an inverse Fourier transform (IDFTdnverse Discrete Fourier Transform) or aFFT (Inverse Fast Fourier Transform) 咅 | 5, a normal Z-serial conversion unit, a guard It has an interval insertion unit, a digital Z analog conversion unit, a frequency conversion unit, etc. That is, the transmitter 121 uses these functional units to send control information passed from other functional units (not shown), transmission data sent from the scheduler 127 (user data), and transmission from the pilot data generating unit 122. An OFDM signal in which pilot data to be multiplexed is multiplexed is generated. The generated OFDM signal is finally subjected to high frequency conversion and transmitted from the antenna 101.

 FIG. 3 shows an example of a radio frame format of the OFDM signal generated by the transmitter 121. The transmitter 121 in this embodiment is assumed to generate an OFDM signal having such a radio frame format. According to the example shown in FIG. 3, the communication channels assigned to the own base station are channels CH1, CH2, and CH3. Also, pilot channels Pl, P2, and P3 corresponding to each communication channel are arranged.

 In addition, the transmitter 121 sends a notification signal based on the notification information transmitted from the notification information generation unit 123 to the antenna 101 as needed. As a result, this notification signal is transmitted from the antenna 101. Broadcast information generating section 123 generates broadcast information including identification information for identifying its own base station, communication resource information, etc., and passes this broadcast information to transmitter 121.

The pilot data generating unit 122 includes a pilot data holding unit 129 (129-1, 129-2,..., 129-n), a control unit 124, a combining unit 125, and the like. The pilot data generation unit 122 generates pilot data (pilot signal) subjected to transmission power control by the control unit 124 and sends it to the transmitter 121. [0036] The pilot data holding unit 129 holds pilot data corresponding to each of the communication channels CH1, CH2, and CH3 (pilot data holding units 129-1, 129-2, 129-3). The pilot data corresponding to each channel is given predetermined transmission power based on an instruction from the control unit 124, and the pilot data is arranged by the combining unit 125 and sent to the transmitter 121.

 [0037] As shown in FIG. 4 or 5, the control unit 124 holds information on transmission power of each pilot channel corresponding to each communication channel allocated to the own base station, and based on this information The transmission power to be given to each pilot channel is determined. FIG. 4 shows transmission power of pilot channels Pl, P2 and P3 in the base station BS1, and FIG. 5 shows transmission power of pilot channels P1, P2 and P3 in the base station BS2.

 [0038] Since channel CH1 is assigned as a priority channel to base station BS1, pilot channel P1 corresponding to channel CH1 has a transmission power of pilot channel P2 corresponding to other channels CH2 and CH3. And set to be higher than P3! Similarly, since channel CH2 is assigned as a priority channel to base station BS2, the transmission power of pilot channel P2 corresponding to channel CH2 is higher than pilot channels P1 and P3 corresponding to other channels CH1 and CH3. It is set to be high.

 [0039] Thus, the mobile station that has received the pilot channel can determine which channel should be used for transmission. FIG. 6 is a diagram conceptually showing an example of the relationship between the notch channel transmission power and the available channel of the mobile station in the wireless communication system of this embodiment. In FIG. 6, as described above, the base station BS1 is set such that the transmission power of the pilot channel P1 corresponding to the priority channel CH1 is higher than the others, and the base station BS2 It is shown that the transmission power of pilot channel P2 corresponding to priority channel CH2 is set to be higher than the others.

[0040] In such a case, the mobile station existing in the vicinity of the base station BS1 (symbol 11) can receive all of the slot channels, but is in a region far away from the base station BS1 (symbol 1). ), The reception level of the pilot channel P1 alone or with it is low. Receive pilot channels P2 and P3. Accordingly, mobile station MS 1 shown in FIG. 6 can determine that channel CH 1 corresponding to pilot channel p 1 should be used for transmission.

 [0041] Similarly, a mobile station existing in the vicinity of base station BS2 (reference numeral 21) is capable of receiving all pilot channels. A mobile station existing in an area away from base station BS2 (reference numeral 2) Receives the pilot channels P1 and P3 in which the reception level is low only or together with the pilot channel P2. Accordingly, it can be determined that the mobile station MS2 shown in FIG. 6 can transmit using all the channels CH1, CH2, and CH3.

 [0042] The scheduler 127 sends transmission data (user data) sent from another functional unit (not shown) to the communication channels CH1, CH2, and CH3 assigned to the own base station, and the misaligned channel. Decide which symbol to arrange. At this time, scheduler 127 determines the arrangement of transmission data to each mobile station based on the CQI information of each mobile station passed from response information collection section 113. Since the CQI information is transmitted from each mobile station in association with each channel, the scheduler 127 selects a channel to which transmission data for each mobile station should be allocated based on the CQI information.

 [0043] For example, when the CQI information related to mobile station MS1 is only for channel CH1, scheduler 127 arranges transmission data for mobile station MS1 in a predetermined symbol in channel CH1. If the CQI information related to mobile station MS2 is all for channels CH1, CH2 and CH3, scheduler 127 places the transmission data for mobile station MS2 in any of channels CH1, CH2 and CH3. Note that the present invention does not limit a specific arrangement determination method by the scheduler 127, such as whether the transmission data is arranged in a shifted manner or in which symbol in the channels. ,.

 [Communication terminal apparatus]

Next, an outline of the functional configuration of the communication terminal apparatus (mobile station) (MS 1 and MS 2) will be described with reference to FIG. FIG. 7 is a block diagram showing an outline of the functional configuration of the communication terminal apparatus. As shown in FIG. 7, the mobile station includes an antenna 201, a receiver 202, a transmitter 203, and a pilot. A determination unit 205, a response information generation unit 207, a data processing unit 208, and a control unit 210 are included. Each of these functional units may be realized by a nodeware circuit, or may be realized by loading a control program stored in a memory into a CPU (Central Processing Unit) and executing it. Also good. In FIG. 7, only functional units related to the present invention are shown.

<Receiver>

 Receiver 202 includes a frequency conversion unit, an analog Z digital conversion unit, a guard interval removal unit, a serial Z parallel conversion unit, a Fourier transform (DFT (Discrete Fourier Transform) or FFT (Fast Fourier Transform)) unit, and a parallel Z serial conversion. Part, demodulation part, decoding part, etc. The receiver 202 demodulates and decodes the OFDM signal received by the antenna 201 by these functional units, and sends the obtained user data, control data, and the like to the data processing unit 208.

 In addition, receiver 202 transmits a pilot signal among signals obtained as a result of frequency conversion, digital conversion, and Fourier conversion of the received OFDM signal to pilot determination section 205. In the example of the radio frame format shown in FIG. 3, pilot signals Pl, P 2 and P 3 are passed to pilot determination section 205.

 <Data processing unit>

 The data processing unit 208 processes user data sent from the receiver 202. In addition, the data processing unit 208 sends user data to be transmitted, control information, and the like to the transmitter 203.

 [0048] <Transmitter>

 The transmitter 203 includes a serial Z parallel conversion unit, a modulation unit, an inverse Fourier transform (IDFT or IF FT) unit, a parallel Z serial conversion unit, a guard interval insertion unit, a digital Z analog conversion unit, a frequency conversion unit, and the like. . The transmitter 203 uses these functional units to generate an OFDM signal in which user data, control information, and the like sent from the data processing unit 208 are multiplexed. The generated OFDM signal is finally subjected to high frequency conversion and transmitted from the antenna 201.

<Pilot determination unit>

The pilot determination unit 205 receives the pilot signal passed from the receiver 202 and receives each pilot signal. Measure the reception level of each pilot signal. The pilot signal is arranged to correspond to the communication channel assigned to each base station as described above. Therefore, pilot determination section 205 measures the reception level of the pilot signal corresponding to each channel transmitted from the base station. The pilot determination unit 205 sends the measured reception level of the pilot signal indicated by the control unit 210 to the response information generation unit 207 in association with the communication channel corresponding to the pilot signal.

 <Response information generation unit>

 Response information generation section 207 generates CQI information for each channel based on the reception level passed from pilot determination section 205. For example, the response information generation unit 207 may store a CQI information table in which the reception level and the CQI information are associated, and generate the CQI information by referring to the CQI information table. The generated CQI information is sent to the transmitter 203.

 [0051] <Control unit 210>

 Control section 210 selects a pilot signal reception level measured by pilot determination section 205 that should generate CQI information. Control unit 210 instructs pie mouth determination unit 205 of the selection result. For example, the control unit 210 holds a predetermined threshold in advance, and instructs the pilot determination unit 205 to send the reception level of the pilot signal having a reception level larger than the predetermined threshold to the response information generation unit 207.

 [Operation example]

Next, an operation example of the wireless communication system in the present embodiment will be described with reference to FIG. In the example of FIG. 6, as described above, the base station BS1 transmits a signal set such that the transmission power of the pilot channel P1 corresponding to the priority channel CH1 is higher than the others, and the base station BS1 BS2 transmits a signal set so that the transmission power of pilot channel P2 corresponding to priority channel CH2 is higher than the others. The mobile station MS1 is located near the cell edge in the communicable area 1 of the base station BS1, and the mobile station MS2 is located near the base station in the communicable area 2 of the base station BS2. [0053] When receiving the signal transmitted from the base station BS1, the mobile station MSI extracts a pilot signal from the signal (receiver 202). The mobile station MS1 measures the reception level of the pilot signal allocated to each channel (pilot determination unit 205). At this time, the reception level of pilot channel P1 is high, and the reception levels of other pilot channels P2 and P3 are low.

 [0054] Mobile station MS1 determines that a channel in which a pilot signal having a reception level higher than a predetermined threshold is allocated is an available channel (control unit 210). In this case, the mobile station MS1 determines that the communication channel CH1 corresponding to the pilot channel P1 is an available channel.

 [0055] The mobile station MS1 generates CQI information related to the available channel CH1 (response information generation unit 207). The mobile station MS1 transmits this CQI information to the base station BS1 together with information indicating that the CQI information belongs to channel CH1.

 [0056] The base station BS1 that has received this CQI information determines that the transmission data to the mobile station MS1 should be transmitted through the channel CH1 because this CQI information is transmitted only for the channel CH1. Yes (scheduler 127).

 On the other hand, when receiving a signal transmitted from the base station BS2, the mobile station MS2 extracts a pilot signal from the signal (receiver 202). Mobile station MS2 measures the reception level of the pilot signal arranged in each channel (pilot determination section 205). At this time, since the mobile station MS2 is located in the vicinity of the base station BS2, the reception levels of the pilot channels Pl, P2, and P3 are increased.

 [0058] Mobile station MS2 determines that a channel in which a pilot signal having a reception level higher than a predetermined threshold is allocated is an available channel (control unit 210). In this case, the mobile station MS2 determines that the channels CH1, CH2, and CH3 in which the pilot channels Pl, P2, and P3 are arranged are usable channels.

[0059] The mobile station MS2 generates CQI information for the available channels CH1, CH2, and CH3, respectively (response information generation unit 207). The mobile station MS2 transmits each CQI information to the base station BS2 together with information indicating that each CQI information belongs to each channel CH1, CH2, and CH3. [0060] The base station BS2 that has received the CQI information has received the CQI information for the channels CH1, CH2, and CH3, so that the transmission data to the mobile station MS2 is the channel CH1, CH2, and so on. Decide what should be transmitted by CH3 (scheduler 127).

 <Operation and Effect in the Present Embodiment>

 Hereinafter, the operation and effect of the wireless communication system in the above-described embodiment will be described. In the wireless communication system according to the present embodiment, the same plurality of communication channels are respectively assigned to adjacent base station apparatuses, and at least one of the channels is prioritized so that the adjacent base station apparatuses do not overlap. Assigned as a channel.

 [0062] Each base station apparatus is set so that the transmission power of the pilot channel corresponding to the priority channel allocated to itself is higher than the transmission power of the pilot channel corresponding to the other communication channels. To do.

 [0063] Thereby, the mobile station apparatus that has received the pilot signal transmitted from the base station apparatus receives all the pilot signals when the mobile station apparatus exists in a position close to the base station apparatus power according to the position. However, when the base station apparatus power is also at a far position, only the pilot signal corresponding to the priority channel or the pilot signal other than that is received with the reception level being low.

 [0064] That is, in the mobile station apparatus, a pilot signal is extracted from the received signal, the reception level of each extracted pilot signal is measured, and a reception level higher than a predetermined threshold among the measured reception levels is measured. The communication channel corresponding to the pilot signal having is determined as an available channel. The mobile station apparatus generates CQI information for each communication channel determined as an available channel, and transmits the CQI information to the base station apparatus.

 [0065] In the base station apparatus, communication channels that can be used by each mobile station apparatus are recognized based on the CQI information sent from each mobile station apparatus. For example, a communication channel in which CQI information is not transmitted is recognized as not an available channel for the mobile station device.

[0066] Thus, according to the wireless communication system in the present embodiment, the mobile station apparatus measures the reception level of the nano-channel, thereby obtaining an appropriate profit according to the position of the presence. Available channels can be determined. As a result, even if a plurality of identical communication channels are assigned to adjacent base station apparatuses, the mobile station apparatus determines available channels that do not cause interference, while maintaining high communication quality. High frequency utilization efficiency can be realized.

 [Modification]

 In the wireless communication system in the above-described embodiment, OFDM is used as a wireless communication system between a base station and a mobile station. However, a TDMA (Time Division Multiple Access) system, a CDMA system, a W-CDMA system, etc. May be used. In this case, the mobile stations MS 1 and MS 2 may be configured to correspond to the receiver 202 and the transmitter 203, and the base stations BS 1 and BS 2 may be configured to correspond to the transmitter 121 and the receiver 111.

Claims

The scope of the claims  [1] For a base station device that uses a plurality of communication channels and pilot channels corresponding to each of these communication channels to wirelessly communicate with a mobile station!  Power control means for setting at least one of the plurality of communication channels as a priority channel and setting a transmission power of a pilot channel corresponding to the priority channel higher than a transmission power of a pilot channel corresponding to another communication channel;  A base station apparatus comprising:  [2] The apparatus further comprises selection means for selecting a communication channel corresponding to the channel information transmitted from the mobile station among the plurality of communication channels as a communication channel used for transmitting data addressed to the mobile station.  The base station apparatus according to claim 1.  [3] The base station apparatus according to claim 1, wherein the power control means determines that the priority channel does not overlap between adjacent base station apparatuses.  [4] A plurality of communication channels and a pilot channel corresponding to each of the communication channels are allocated, and the transmission power of a pilot channel corresponding to at least one of the plurality of communication channels is assigned to another communication channel. Set higher than the transmission power of the pilot channel corresponding to the mobile station device that communicates wirelessly with the base station.  Measurement means for measuring the reception level of the pilot channel transmitted by the base station power; and determination means for determining at least one of the plurality of communication channels as an available communication channel according to the reception level;  A mobile station apparatus comprising:  [5] The determination means determines a communication channel corresponding to a pilot channel having a reception level larger than a predetermined threshold among the reception levels measured by the measurement means as an available communication channel.  The mobile station apparatus according to claim 4. 6. The mobile station apparatus according to claim 4, further comprising transmission means for generating channel information related to the available communication channel and transmitting the channel information to the base station. [7] In a mobile communication system having a mobile station and a base station, wherein the mobile station and the base station communicate wirelessly using a plurality of communication channels and pilot channels corresponding to the communication channels.  The base station  Power control means is provided for setting at least one of the plurality of communication channels as a priority channel and setting the transmission power of a pilot channel corresponding to the priority channel higher than the transmission power of pilot channels corresponding to other communication channels. ,  The mobile station  Measuring means for measuring the reception level of the pilot channel transmitted by the base station power; and  Determining means for determining at least one of the plurality of communication channels as an available communication channel according to the reception level;  A mobile communication system comprising:  [8] The mobile station determination means determines a communication channel corresponding to a pilot channel having a reception level larger than a predetermined threshold among the reception levels measured by the measurement means as an available communication channel.  The mobile communication system according to claim 7. 9. The mobile communication system according to claim 7, wherein the power control means of the base station determines that the priority channel is not overlapped between adjacent base stations. [10] The mobile station  Further comprising transmission means for generating channel information related to the available communication channel and transmitting it to the base station;  The base station  The mobile station further comprises selection means for selecting at least one communication channel to be used for transmitting data addressed to the mobile station from the plurality of communication channels based on the channel information transmitted.  The mobile communication system according to claim 7. [11] The base station selection means is a communication unit corresponding to channel information transmitted from the mobile station. 11. The mobile communication system according to claim 10, wherein a communication channel is selected as a communication channel used for transmitting data addressed to the mobile station.