JP4378368B2 - Mobile communication system, base station apparatus, mobile station apparatus, and multicarrier communication method - Google Patents

Description

  The present invention relates to a mobile communication system, a base station apparatus, a mobile station apparatus, and a multicarrier communication method, and more particularly to a frequency division multiple access scheme that performs multicarrier transmission in each of a plurality of channels.

  A multi-carrier transmission system represented by OFDM (Orthogonal Frequency Division Multiplexing) is a system in which transmission data for one channel is distributed and transmitted to a plurality of carrier waves (called subcarriers) having different frequencies. is there. If a plurality of transmission channels (referred to as sub-channels) using the same transmission method are arranged in the frequency direction, frequency division multiple access with an excellent transmission rate can be realized. For example, OFDMA (Orthogonal Frequency Division Multiple Access) is a multiple access scheme that utilizes the characteristics of OFDM. In such a multiple access method, in order to prevent so-called adjacent channel interference in which adjacent subchannel bands overlap due to fading or the like, a guard band (guard band) having a predetermined width is provided between adjacent subchannels in the frequency direction. ing.

Patent Document 1 below discloses a technique for dividing radio resources in the time direction in a base station subsystem and flexibly and dynamically controlling allocation of radio resources to each user.
JP-A-10-190621

  In general, when two or more subchannels adjacent in the frequency direction are assigned to the same apparatus, it is very rare that adjacent channel interference occurs between them. Since the transmission signals related to these subchannels have the same transmission source and close carrier frequencies, there is almost no difference in the influence of fading on the wireless propagation path, and the displacement amount of the carrier frequency of these signals is almost the same. It is because it becomes a grade.

  However, in a conventional mobile communication system to which a frequency division multiple access (for example, OFDMA) scheme using a plurality of subchannels is applied, two or more subchannels adjacent in the frequency direction are assigned to the same mobile station apparatus. In addition, a guard band is uniformly provided between the subchannels. For this reason, the communication band is lost by the guard band, and the limited frequency resources cannot be used effectively.

  The present invention has been made in view of the above-described conventional problems. A mobile communication system, a base station apparatus, a mobile station apparatus, and multicarrier communication capable of improving frequency use efficiency and improving data transmission speed. It aims to provide a method.

  In order to achieve the above object, a mobile communication system according to the present invention includes a base station apparatus that performs communication by a frequency division multiple access scheme using a plurality of subchannels and a plurality of mobile station apparatuses, and the base station An apparatus comprises channel allocating means for allocating at least two subchannels to each mobile station apparatus as allocation channels, and each mobile station apparatus communicates with the base station apparatus using the allocated channel. In the communication system, a guard band having a predetermined width is provided between the subchannels adjacent to each other in the frequency direction, and the base station apparatus includes two of the allocated channels adjacent to each other in the frequency direction. First subchannel selection means for selecting the above subchannels, and the two or more subchannels selected by the first adjacent channel selection means. The guard band provided between each of the mobile station apparatuses further communicates with each of the mobile station apparatuses, and each of the mobile station apparatuses includes two or more subchannels adjacent in the frequency direction among the allocated channels. And further using the guard band provided between each of the two or more sub-channels selected by the second adjacent channel selection means, the second adjacent channel selection means for selecting the base station apparatus, It is characterized by communication.

  According to the present invention, when there are two or more subchannels adjacent to each other in the frequency direction among at least two subchannels used for communication, the guard band provided between each of these subchannels is further used. Make communication. In this way, a guard band that is not originally necessary for preventing adjacent channel interference can be used as a communication band, and the data transmission speed can be improved.

  Further, the base station apparatus includes: a non-adjacent channel selection unit that selects a sub-channel that is not adjacent to any other sub-channel related to the allocation channel among the allocation channels; and any one related to the allocation channel And an adjacent empty channel selection means for selecting an empty subchannel adjacent to the subchannel in the frequency direction, wherein the channel allocation means replaces the subchannel selected by the non-adjacent channel selection means with the adjacent channel. Any of the free subchannels selected by the free channel selection means may be allocated to each mobile station device. This makes it possible to use more guard bands as communication bands and further improve the data transmission speed.

  The frequency division multiple access may be orthogonal frequency division multiple access.

  A base station apparatus according to the present invention is a base station apparatus that communicates with each of a plurality of mobile station apparatuses using at least two subchannels by a frequency division multiple access scheme using a plurality of subchannels. A guard band having a predetermined width is provided between each of the subchannels adjacent in the frequency direction, and of the at least two subchannels used for communication with each of the mobile station apparatuses, adjacent in the frequency direction. Each of the movements further includes adjacent channel selection means for selecting two or more subchannels, and further using the guard band provided between each of the two or more subchannels selected by the adjacent channel selection means. It is characterized by communicating with a station device.

  A mobile station apparatus according to the present invention is a mobile station apparatus that communicates with a base station apparatus using at least two of the subchannels by a frequency division multiple access scheme using a plurality of subchannels. A guard band having a predetermined width is provided between each of the subchannels adjacent to each other, and two or more of the at least two subchannels used for communication with the base station apparatus are adjacent in the frequency direction. Including an adjacent channel selection means for selecting a subchannel, and further using the guard band provided between each of the two or more subchannels selected by the adjacent channel selection means to communicate with the base station apparatus It is characterized by doing.

  Also, the multicarrier communication method according to the present invention is a multicarrier communication method in a communication device that communicates with another communication device using at least two subchannels by a frequency division multiple access method using a plurality of subchannels. A guard band having a predetermined width is provided between the sub-channels adjacent in the frequency direction, and the frequency direction of the at least two communication channels used for communication with the other communication device is An adjacent channel selection step for selecting two or more subchannels adjacent to each other, further using the guard band provided between each of the two or more subchannels selected in the adjacent channel selection step, It communicates with said other communication apparatus, It is characterized by the above-mentioned.

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

  FIG. 1 is an overall configuration diagram of a mobile communication system according to an embodiment of the present invention. As shown in the figure, the mobile communication system 1 includes a base station apparatus 10 and a plurality of mobile station apparatuses 12 (three here).

  Each mobile station device 12 performs wireless communication with the base station device 10, and is, for example, a portable mobile phone or a portable information terminal. Here, data is transmitted / received to / from the base station apparatus 10 by the TDD (Time Division Duplex) method, and multiplex communication is performed by the TDMA (Time Division Multiple Access) method and the OFDMA method. Furthermore, the base station apparatus 10 includes an adaptive array antenna as will be described later. With this adaptive array antenna, each of the plurality of mobile station apparatuses 12 and the SDMA (SDMA) in the same time slot and the same carrier frequency. Multiplex communication is performed by the (Space Division Multiple Access) method. Thus, bidirectional communication with a plurality of mobile station apparatuses 12 is performed with extremely high frequency utilization efficiency.

  FIG. 4 is a diagram illustrating an example of a time slot configuration (for one TDMA frame) based on TDMA / TDD and a subchannel configuration based on OFDMA. As shown in the figure, the downlink (radio transmission path from the base station apparatus 10 to the mobile station apparatus 12) and the uplink (radio transmission path from the mobile station apparatus 12 to the base station apparatus 10) each have four times. It consists of slots. Each time slot is composed of 28 subchannels, one of which is used as a control channel (CCH) and the remaining 27 subchannels are used as communication channels (TCH). . A guard band (not shown) having a predetermined width is provided between adjacent subchannels adjacent to each other in the frequency direction in order to prevent adjacent channel interference.

  The base station apparatus 10 allocates at least some of the subchannels (27 subchannels × 4 slots) used as communication channels in the downlink and uplink to each mobile station apparatus 12. . Specifically, as shown in FIG. 4, one anchor subchannel (ASCH) and one or more extra subchannels (ESCH) are allocated to each mobile station apparatus 12.

  ASCH is a subchannel that is determined when a link is established (communication start) and is notified to each mobile station apparatus 12 using CCH. MAP information (108-bit bit string) indicating one or a plurality of ESCHs and other It is used to transmit / receive control information and the like. On the other hand, the ESCH is a subchannel that is determined after link establishment and is specified by MAP information notified to each mobile station measure 12 using the ASCH, and is mainly used for transmission / reception of communication data. As shown in the figure, ASCH and ESCH are symmetrical in downlink slot and uplink slot (DL # 1 and UL # 1, DL # 2 and UL # 2,...) Corresponding to slot numbers. Assigned.

  Hereinafter, configurations and operations of the base station apparatus 10 and the mobile station apparatus 12 will be described.

  FIG. 2 is a functional block diagram of the base station device 10 and the mobile station device 12. As shown in the figure, the base station apparatus 10 includes an adaptive array antenna 20, a receiving unit 22, an FFT (Fast Fourier Transform) unit 24, a composite unit 26, a control unit 28, a distributing unit 34, an IFFT (Inverse). A Fast Fourier Transform (inverse Fast Fourier Transform) unit 36 and a transmission unit 38 are included.

  The adaptive array antenna 20 is an array of a plurality of antennas, receives a radio signal transmitted from each mobile station apparatus 12 by each antenna, and outputs the received signal to the receiving unit 22. In addition, a signal input from the transmission unit 38 is transmitted from each antenna. Note that reception and transmission are switched in a time division manner.

  The receiving unit 22 includes a low-noise amplifier, a down converter, a space division processing unit, a time division processing unit, a symbol synchronization unit, and an A / D converter. The baseband OFDM from each mobile station apparatus 12 is received from the received signal. The sample value related to the signal is separated and extracted. That is, the signal input from the adaptive array antenna 20 is space division multiplexed (SDMA), time division multiplexed (TDMA), and orthogonal frequency division multiplexed (OFDMA). After amplification and down-conversion, space division processing and time division processing relating to weight control of the adaptive array antenna 20 are performed. Next, symbol synchronization and removal of a guard interval (GI) signal are performed on the separated signal to obtain a baseband OFDM signal. Then, after A / D converting the baseband OFDM signal, the sample value is output to the FFT unit 24.

  The FFT unit 24 performs FFT on the sample value input from the receiving unit 22 and acquires each subcarrier component of the OFDM symbol.

  The combining unit 26 combines (combines) each subcarrier component of the OFDM symbol input from the FFT unit 24 for each predetermined number of subcarriers to generate a symbol string, and decodes the symbol string to move each subcarrier component. Received data from the station device 12 is acquired. Each reception data obtained in this way is output to a host device (not shown).

  Here, the process in which the composite unit 26 acquires the reception data from each mobile station device 12 will be described in more detail. The combining unit 26 combines the OFDM symbols for each subcarrier for one subchannel while referring to the subchannel allocation status by the channel allocation unit 32, and generates a symbol string related to each subchannel. In addition, as a result of determination by the adjacent determination unit 30 described later (selection by the adjacent channel selection unit 40), at least two subchannels (hereinafter referred to as allocation channels) allocated to each mobile station apparatus 12 by the channel allocation unit 32. If it is determined that there are two or more subchannels adjacent to each other in the frequency direction, OFDM symbols are also combined for subcarriers in each guard band provided between the two or more subchannels. Then, a symbol string related to each guard band is generated. Then, the generated symbol sequences are decoded, and in addition to the reception data related to each sub-channel, the reception data related to each guard band is acquired. In this case, each mobile station apparatus 12 transmits data using subcarriers in each guard band.

  FIG. 5A is a diagram illustrating an example of transmission / reception data related to only a subchannel. As shown in the figure, conventionally, even when there are two or more subchannels adjacent to each other in the frequency direction among the allocated channels, a guard band is uniformly provided between the subchannels. As described above, in such a case, it is extremely rare that adjacent channel interference occurs, and therefore, a communication band loss has occurred for the guard band.

  On the other hand, FIG.5 (b) is a figure which shows the example which further added the transmission / reception data which concerns on the guard band to the transmission / reception data which concerns on this embodiment in this embodiment. As shown in the figure, in the mobile communication system 1 according to the present embodiment, when there are two or more subchannels adjacent to each other in the frequency direction among the allocated channels, the conventional communication between these subchannels is present. Since the guard band provided is used as a communication band, the transmission area (payload) can be increased by the extension shown in FIG. 5B compared to the conventional case, and the data transmission speed can be improved.

  The control unit 28 is connected to the reception unit 22, the FFT unit 24, the composite unit 26, the distribution unit 34, the IFFT unit 36, the transmission unit 38, and the like, and controls the entire base station apparatus 10. For example, the sub-channel frequency and transmission / reception timing in the reception unit 22 and the transmission unit 38, the FFT execution timing and calculation target range in the FFT unit 24, the composite timing of received data in the composite unit 26, and the like are controlled. In addition, an adjacency determination unit 30 and a channel allocation unit 32 are included, and channel allocation such as ASCH and ESCH to each mobile station apparatus 12 is controlled. The control unit 28 is configured mainly by a CPU (Central Processing Unit) and a memory, and the above functions are realized by the CPU executing various control programs stored in the memory. Is done.

  FIG. 3 is a functional block diagram of the adjacency determination unit 30. As shown in the figure, the adjacency determination unit 30 includes an adjacent channel selection unit 40, a non-adjacent channel selection unit 42, and an adjacent empty channel selection unit 44. Whether there are two or more subchannels adjacent to each other in the frequency direction among at least two subchannels allocated to the station apparatus 12), and any other subchannels related to the allocation channel among the allocation channels in the frequency direction. It is determined whether or not there are non-adjacent subchannels and whether or not there is a free subchannel (subchannel not used for communication) adjacent to any subchannel related to the assigned channel in the frequency direction. Is.

  In response to a link establishment request from each mobile station apparatus 12, the channel allocation unit 32 selects one ASCH to be allocated to the mobile station apparatus 12 from among 108 subchannels, and from each mobile station apparatus 12 In response to an ESCH allocation request or a terminal call request from the network to which the base station apparatus 10 is connected, one or more ESCHs to be allocated to the mobile station apparatus 12 are selected from 107 subchannels excluding the ASCH. Is. FIG. 6 is a diagram illustrating an example of an assignment state of subchannels (one ASCH and one or a plurality of ESCHs) by the channel assignment unit 32. In the figure, a, b, and c indicate subchannels allocated by the channel allocation unit 32 to the mobile station devices a, b, and c, respectively, and the others indicate empty subchannels.

  Further, the channel allocation unit 32 appropriately assigns an allocation channel to each mobile station apparatus 12 according to a new link establishment request, a change in quality information related to communication with each mobile station apparatus 12, a subchannel allocation status, and the like. change. The process of changing the allocation channel for each mobile station apparatus 12 according to the subchannel allocation status will be described later.

  The adjacent channel selection unit 40 selects two or more subchannels adjacent to each other in the frequency direction among the allocation channels for each mobile station apparatus 12 according to the subchannel allocation status by the channel allocation unit 32. For example, when the subchannel allocation status related to the mobile station apparatus b is the status shown in FIG. 6A, the adjacent channel selection unit 40 sets two groups surrounded by bold lines among the allocated channels for the mobile station apparatus b. Select a subchannel.

  The non-adjacent channel selection unit 42 determines, for each mobile station apparatus 12, any other sub-channel related to the allocated channel among the allocated channels for each mobile station apparatus 12 according to the subchannel allocation status by the channel allocation unit 32. Sub-channels that are not adjacent to each other in the frequency direction (hereinafter referred to as non-adjacent channels) are selected. For example, when the subchannel allocation status relating to the mobile station device b is the status shown in FIG. 6A, the non-adjacent channel selection unit 42 among the allocation channels for the mobile station device b, FIG. 5 sub-channels surrounded by a thick line are selected.

  The adjacent vacant channel selection unit 44, depending on the subchannel allocation status by the channel allocating unit 32, vacant subchannels (hereinafter referred to as adjacent subchannels) adjacent to any one of the allocated channels for each mobile station apparatus 12 in the frequency direction. (Referred to as an empty channel). For example, when the subchannel allocation status related to the mobile station device b is the status shown in FIG. 6A, the adjacent empty channel selection unit 44 determines whether any subchannel related to the allocation channel for the mobile station device b As empty subchannels adjacent in the frequency direction, two empty subchannels surrounded by a thick line shown in FIG. Note that the free subchannel here is not only a subchannel that is not used for communication at that time, but also immediately (for example, the next TDMA) in accordance with the subchannel allocation change related to another mobile station apparatus 12. It may be a subchannel that is scheduled to be unused for communication (in a frame).

  Next, processing in which the channel allocation unit 32 changes the allocation channel for each mobile station apparatus 12 according to the subchannel allocation status will be described. That is, the channel allocation unit 32 changes the allocation channel so that the allocation channel for each mobile station apparatus 12 is adjacent in the frequency direction as much as possible. Specifically, instead of the subchannel (non-adjacent channel) selected by the non-adjacent channel selection unit 42, any one of the free subchannels (adjacent free subchannels) selected by the adjacent free channel selection unit 44, Assigned to each mobile station device 12.

  For example, when the sub-channel allocation status relating to the mobile station apparatus b is the status shown in FIG. 6A, as described above, the non-adjacent channel selection unit 42 is surrounded by the thick line shown in FIG. Five subchannels are selected as non-adjacent channels. Also, the adjacent empty channel selection unit 44 selects two empty subchannels surrounded by a thick line shown in FIG. Here, the channel allocating unit 32 replaces the left subchannel among the five subchannels surrounded by the thick line shown in FIG. When two empty subchannels surrounded by the bold lines shown are allocated, the subchannel allocation status is as shown in FIG. That is, of the allocated channels for the mobile station apparatus b, the number of subchannels adjacent in the frequency direction is increased by one set compared to the case of FIG. As a result, by increasing the number of subchannels adjacent in the frequency direction, more guard bands can be used as communication bands, and the data transmission speed is further improved.

  Distribution section 34 converts transmission data to each mobile station apparatus 12 input from a host apparatus (not shown) into a symbol string by symbol mapping, separates the obtained symbol string into subcarrier components, and IFFT section 36. Is output. Specifically, referring to the subchannel allocation status by the channel allocation unit 32, the symbol sequence obtained by symbol mapping for the transmission data to each mobile station apparatus 12 is assigned to each of the allocation channels for that mobile station apparatus 12. Distribute to subcarriers. If it is determined by the adjacency determination unit 32 (selection by the adjacent channel selection unit 40) that there are two or more subchannels adjacent in the frequency direction among the allocated channels, the symbol string is Further, it is also distributed to subcarriers in each guard band provided between each of the two or more subchannels. In this case, each mobile station apparatus 12 receives data using subcarriers in each guard band. Thus, when there are two or more subchannels adjacent to each other in the frequency direction among the allocated channels, the guard band conventionally provided between the subchannels is used as a communication band. Similarly, the transmission area (payload) can be increased by the extension shown in FIG. 5B compared to the conventional case, and the data transmission speed can be improved.

  The IFFT unit 36 performs IFFT on each subcarrier component of the OFDM symbol input from the distribution unit 34 and sequentially outputs the obtained signals to the transmission unit 38.

  The transmission unit 38 includes a D / A converter, a time division multiplex processing unit, a space division multiplex processing unit, an up converter, and an amplifier. The transmission unit 38 performs D / A conversion on signals sequentially input from the IFFT unit 38, Get to baseband OFDM signal. Next, a guard interval signal is added to the baseband OFDM signal, and a signal subjected to time division multiplexing processing and space division multiplexing processing related to weight control of the adaptive array antenna 20 is generated. Then, the generated signal is up-converted into a radio signal, amplified to the transmission output level, and supplied to the adaptive array antenna 20.

  Next, each functional block of the mobile station apparatus 12 will be described. As shown in FIG. 2, the antenna 50, the reception unit 52, the FFT unit 54, the composite unit 56, the control unit 58, the distribution unit 64, the IFFT unit 66, and the transmission unit 68 are configured. The receiving unit 52, the FFT unit 54, the combining unit 56, the distributing unit 64, the IFFT unit 66, and the transmitting unit 68 are the receiving unit 22, the FFT unit 24, the combining unit 26, the distributing unit 34, and the IFFT unit in the base station apparatus 10. 36 and the transmission unit 38, except for the processes related to space division multiplexing and time division multiplexing, are not described here in detail.

  The control unit 58 is connected to the reception unit 52, the FFT unit 54, the composite unit 56, the distribution unit 64, the IFFT unit 66, the transmission unit 68, and the like, and controls the mobile station apparatus 12 as a whole. For example, the subchannel frequency and transmission / reception timing in the reception unit 52 and transmission unit 68, the FFT execution timing and calculation target range in the FFT unit 54, the composite timing of received data in the composite unit 56, and the like are controlled. Further, it includes a channel management unit 60 and an adjacent channel selection unit 62, and performs channel management such as ASCH and ESCH allocated from the base station apparatus 10. The control unit 58 is configured with a CPU and a memory as the center, and the above functions are realized by the CPU executing various control programs stored in the memory.

  The channel management unit 60 manages at least two subchannels (one ASCH and one or a plurality of ESCHs) allocated from the base station apparatus 10.

  The adjacent channel selection unit 62 selects two or more sub-channels adjacent to each other in the frequency direction among at least two sub-channels allocated from the base station apparatus 10 according to the sub-channel allocation status managed by the channel management unit 60. A channel is selected and is a functional block corresponding to the adjacent channel selection unit 40 in the base station device 10.

  Here, the operation of the base station apparatus 10 will be described. FIG. 7 is a flowchart showing a process of changing the allocation channel for any one of the mobile station apparatuses 12 in communication according to the subchannel allocation status.

  Base station apparatus 10 measures the reception quality of each subchannel assigned to mobile station apparatus 12 based on the received signal from mobile station apparatus 12. Then, it is determined whether or not the reception quality is equal to or higher than a predetermined quality (S100).

  In S100, when the reception quality is equal to or higher than the predetermined quality, the non-adjacent channel selection unit 42 determines the allocation channel among the allocation channels for the mobile station apparatus 12 according to the subchannel allocation status by the channel allocation unit 32. A subchannel (non-adjacent channel) that is not adjacent to any other subchannel in the frequency direction is selected (S102). If the reception quality is less than the predetermined quality, it is determined that the channel assignment cannot be changed, and the assigned channel is not changed.

  When at least one non-adjacent channel is selected in S102, the adjacent empty channel selection unit 44 selects one of the allocation channels related to the mobile station apparatus 12 according to the subchannel allocation status by the channel allocation unit 32. An empty subchannel (adjacent empty channel) adjacent to the subchannel in the frequency direction is selected (S104). In addition, when a non-adjacent channel is not selected, the allocation channel is not changed.

  When at least one adjacent free channel is selected in S104, the channel assignment unit 32 assigns one of the adjacent free channels to the mobile station apparatus 12 instead of the non-adjacent channel selected in S102 ( S106). Then, MAP information, which is a 108-bit bit string indicating a new allocated channel, is generated and notified to the mobile station apparatus 12 (S108). If an adjacent empty channel is not selected in S104, the non-adjacent channel selected in S102 cannot be adjacent to any other assigned channel in the frequency direction, so that the assigned channel is not changed. .

  According to the above embodiment, when there are two or more subchannels adjacent to each other in the frequency direction among at least two subchannels used for communication, the guard band provided between each of these subchannels is further used. Therefore, the frequency utilization efficiency can be improved and the data transmission speed can be improved.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible. For example, in the above description, the present invention is applied to a mobile communication system that uses both SDMA, TDMA, and OFDMA. However, the present invention provides a plurality of subchannels using a multicarrier transmission scheme in the frequency direction. The present invention can also be applied to other mobile communication systems that realize connection.

1 is an overall configuration diagram of a mobile communication system according to an embodiment of the present invention. It is a functional block diagram of the base station apparatus and mobile station apparatus which concern on embodiment of this invention. It is a functional block diagram of an adjacent determination part. It is a figure which shows an example of the time slot structure by TDMA / TDD, and the subchannel structure by OFDMA. It is a figure which shows an example which added the transmission / reception data which concerns on only the subchannel, and the transmission / reception data which concerns on the guard band. It is a figure which shows an example of the allocation condition of the subchannel by a channel allocation part. It is a flowchart which shows the allocation channel change process in a base station apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mobile communication system, 10 Base station apparatus, 12 Mobile station apparatus, 20, Adaptive array antenna, 22, 52 Receiving part, 24, 54 FFT part, 26, 56 Composite part, 28, 58 Control part, 30 Adjacent determination part , 32 channel allocation unit, 34, 64 distribution unit, 36, 66 IFFT unit, 38, 68 transmission unit, 40 adjacent channel selection unit, 42 non-adjacent channel selection unit, 44 adjacent free channel selection unit, 50 antenna.

Claims (5)

And a base station apparatus and the transfer Dokyoku equipment communicating using one or more sub-channels by frequency division multiple access scheme, a guard band is provided between the respective subchannels, adjacent in the frequency direction, moving A body communication system ,
When at least two subchannels are allocated to the mobile station apparatus , the base station apparatus changes channel allocation so that part or all of the subchannels allocated to the mobile station apparatus are adjacent in the frequency direction. Including channel assignment changing means,
The base station apparatus and the mobile station apparatus, communication using further the guard band is provided between each two or more sub-channels that are adjacent in the frequency direction by changing the channel allocation by the channel allocation changing means I do,
A mobile communication system. The mobile communication system according to claim 1, wherein
The base station device
Non-adjacent channel selection means for selecting a subchannel that is not adjacent to any other subchannel in the frequency direction among the subchannels allocated to the mobile station device ;
Adjacent empty channel selection means for selecting an empty subchannel adjacent to one of the subchannels allocated to the mobile station apparatus in the frequency direction;
Further including
It said channel allocation changing means, instead of the sub-channels selected by the non-adjacent channel selecting means allocates said one of unused sub-channels selected by the adjacent vacant channel selection means, before KiUtsuri Dokyoku device,
A mobile communication system. The mobile communication system according to claim 1 or 2,
The frequency division multiple access is orthogonal frequency division multiple access;
A mobile communication system. The frequency division multiple access scheme a base station apparatus that communicates with the transfer Dokyoku equipment using one or more sub-channels,
Channel assignment changing means for changing the channel assignment so that part or all of the subchannels assigned to the mobile station apparatus are adjacent in the frequency direction when at least two subchannels are assigned to the mobile station apparatus ,
Further using a guard band is provided between each two or more sub-channels that are adjacent in the frequency direction by changing the channel allocation by the channel assignment changing unit communicates with the front KiUtsuri Dokyoku device,
A base station apparatus. Using one or more sub-channels by frequency division multiple access scheme A multicarrier communication method in a communication apparatus for communicating with another communication device,
When at least two subchannels are allocated to the other communication device, the channel allocation is changed so that a part or all of the subchannels allocated to the other communication device are adjacent in the frequency direction ,
The further use of a guard band provided between each two or more sub-channels that are adjacent in the frequency direction by a change of channel assignment in step communicates with the other communication apparatus,
A multi-carrier communication method.

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