WO2008032560A1 - Mobile communication system, base station apparatus, mobile station apparatus and multicarrier communication method - Google Patents

Abstract

Guard bands each having a predetermined width each are formed between subchannels adjacent to each other in the frequency direction. A base station apparatus (10) includes an adjacency determining part (30) that selects, from among the subchannels allocated to mobile station apparatuses (12) (allocated channels), two or more subchannels adjacent to each other in the frequency direction. The base station apparatus (10) further uses the guard bands, each of which is formed between the subchannels selected by the adjacency determining part (30), to perform communication with the mobile station apparatuses (12). The mobile station apparatuses (12) each include an adjacent channel selecting part (62) that selects, from among the allocated channels, two or more subchannels adjacent to each other in the frequency direction. The mobile station apparatuses (12) further use the guard bands, each of which is formed between the subchannels selected by the adjacent channel selecting part (62), to perform communication with the base station apparatus (10).

Description

 Specification

 Mobile communication system, base station apparatus, mobile station apparatus, and multicarrier communication method

 Technical field

 TECHNICAL FIELD [0001] 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.

 Background art

 [0002] A multi-carrier transmission scheme represented by OFDM (Orthogonal Frequency Division Multiplexing) distributes transmission data for one channel to a plurality of carriers (called subcarriers) having different frequencies. Transmission method. 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 excellent transmission speed can be realized. For example, OFD MA (Orthogonal Frequency Division Multiple Access) is a multiple access method that makes full use of 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 the influence of fading or the like, a guard band (guard band) having a predetermined width is provided between adjacent subchannels in the frequency direction. Establish! /

 [0003] It should be noted that the following Patent Document 1 discloses a technology that divides radio resources in a time direction in a base station subsystem and flexibly and dynamically controls allocation of radio resources to each user. It is disclosed.

 Patent Document 1: JP-A-10-190621

 Disclosure of the invention

 Problems to be solved by the invention

[0004] Generally, when two or more subchannels adjacent in the frequency direction are assigned to the same apparatus, it is extremely rare that adjacent channel interference occurs between them. The transmission signals related to each subchannel share the same transmission source and have a similar carrier frequency. For this reason, there is almost no difference in the effect of fading on the radio propagation path, and the amount of displacement of the carrier frequency of each signal is almost the same.

 [0005] 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 identical to each other. Even when allocating to mobile station devices, a guard band is provided uniformly between these subchannels. For this reason, the communication band is lost by the guard band, and the limited frequency resources cannot be used effectively.

 [0006] 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 a mobile communication system capable of improving frequency use efficiency and improving a data transmission rate. An object is to provide a multi-carrier communication method.

 Means for solving the problem

 [0007] 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 method using a plurality of subchannels, and a plurality of mobile station apparatuses, The base station apparatus includes channel allocating means for allocating at least two subchannels to the mobile station apparatuses as allocation channels, and the mobile station apparatuses communicate with the base station apparatus using the allocated channels. 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 a frequency direction of the allocated channel. The first adjacent channel selection means for selecting two or more subchannels adjacent to each other, and the two or more subchannels selected by the first adjacent channel selection means. Further using the guard band provided between each of the channels, to communicate with each of the mobile station devices, and each of the mobile station devices has two or more adjacent channels in the frequency direction among the allocated channels. A second adjacent channel selection means for selecting a plurality of subchannels, and further using the guard band provided between each of the two or more subchannels selected by the second adjacent channel selection means, It is characterized by communicating with base station equipment

[0008] 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, Communication is further performed using the guard band provided between them. 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.

[0009] Further, the base station apparatus includes non-adjacent channel selection means for selecting a subchannel that is not adjacent in the frequency direction to any other subchannel related to the allocation channel among the allocation channels, and the allocation And an adjacent empty channel selection means for selecting an empty subchannel adjacent in the frequency direction to any of the subchannels related to the channel, wherein the channel allocation means is a subchannel selected by the non-adjacent channel selection means. Instead, any of the free subchannels selected by the adjacent free channel selection means may be allocated to each mobile station apparatus. In this way, it becomes possible to use more guard bands as communication bands, and the power S can further improve the data transmission speed.

 [0010] The frequency division multiple access may be orthogonal frequency division multiple access.

[0011] Further, the base station apparatus according to the present invention uses a frequency division multiple access scheme using a plurality of subchannels to perform communication with each of a plurality of mobile station apparatuses using at least two subchannels. A guard device having a predetermined width is provided between the subchannels adjacent to each other in the frequency direction, and is a station device, out of the at least two subchannels used for communication with the mobile station devices. Including an adjacent channel selection means for selecting two or more subchannels adjacent in the frequency direction, and the guard band provided between each of the two or more subchannels selected by the adjacent channel selection means Further, it is characterized in that communication is performed with each mobile station apparatus by further using a band.

[0012] Further, 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 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 is adjacent in the frequency direction among the at least two subchannels used for communication with the base station apparatus. Including adjacent channel selection means for selecting two or more subchannels, further using the guard band provided between each of the two or more subchannels selected by the adjacent channel selection means, Communication is performed with the base station apparatus.

[0013] Further, the multicarrier communication method according to the present invention is 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. The at least two communication channels used in communication with the other communication device, wherein a guard band having a predetermined width is provided between the subchannels adjacent in the frequency direction. Including an adjacent channel selection step for selecting two or more subchannels adjacent in the frequency direction, and provided between each of the two or more subchannels selected in the adjacent channel selection step. Furthermore, the guard band is further used to perform communication with the other communication device.

 Brief Description of Drawings

 FIG. 1 is an overall configuration diagram of a mobile communication system according to an embodiment of the present invention.

 FIG. 2 is a functional block diagram of a base station apparatus and a mobile station apparatus according to the embodiment of the present invention.

FIG. 3 is a functional block diagram of an adjacency determination unit.

 FIG. 4 is a diagram showing an example of a time slot configuration based on TDMA / TDD and a subchannel configuration based on OFDMA.

 FIG. 5 is a diagram showing an example of transmission / reception data related to only a subchannel and transmission / reception data related to a guard band added thereto.

 FIG. 6 is a diagram showing an example of subchannel allocation status by a channel allocation unit.

 FIG. 7 is a flowchart showing allocation channel change processing in the base station apparatus.

 BEST MODE FOR CARRYING OUT THE INVENTION

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 device 10 and a plurality of mobile station devices 12 (three here).

Each mobile station device 12 performs wireless communication with the base station device 10 and is, for example, a portable cellular phone or a portable information terminal. Here, TDD (Time Division Duplex) It transmits and receives data to and from the base station apparatus 10 using the “division duplex” method, and performs multiplex communication using 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, and a plurality of mobile station apparatuses 12 are used in the same time slot and the same carrier frequency by using the adaptive array antenna. And multiplex communication using SDMA (Space Division Multiple Access) method. In this way, bidirectional communication with a plurality of mobile station apparatuses 12 is performed with extremely high frequency utilization efficiency.

 [0018] FIG. 4 is a diagram illustrating an example of a time slot configuration (for one TDMA frame) by TDMA / TDD and a subchannel configuration by OF DMA. As shown in the figure, the downlink (the radio transmission path from the base station apparatus 10 to the mobile station apparatus 12) and the uplink (the unspring transmission path from the mobile station apparatus 12 to the base station apparatus 10) are: Each consists of four timeslot forces. Each time slot consists of 28 subchannels, one of which is used as a control channel (CCH: Control Channel) and the remaining 27 subchannels are used as communication channels (TCH: Traffic Channel). . In addition, a guard band (not shown) having a predetermined width is provided between adjacent subchannels in the frequency direction to prevent adjacent channel interference.

 [0019] The base station apparatus 10 transmits at least a part of a total of 108 subchannels (27 subchannels x 4 slots) used as communication channels in each downlink and uplink to each mobile station. Assign to device 12. Specifically, as shown in FIG. 4, one anchor subchannel (ASCH: Anchor Sub Channel) and one or a plurality of extra subchannels (ESCH: Extra Sub Channel) are allocated to each mobile station apparatus 12.

[0020] ASCH is a subchannel determined at the time of link establishment (at the start of communication) and notified to each mobile station apparatus 12 using CCH, and MAP information (108 bits) indicating one or a plurality of ESCHs. Bit strings) and other control information. 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 apparatus 12 using the ASCH, and is mainly used for transmission / reception of communication data. As shown in the figure, the downlink corresponding to the slot number Slots and uplink slots (DL # 1 and UL # 1, DL # 2 and UL # 2, ...) are assigned ASCH and ESCH symmetrically.

In the following, the configuration / operation of base station apparatus 10 and mobile station apparatus 12 will be described.

FIG. 2 is a functional block diagram of base station apparatus 10 and mobile station apparatus 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 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. Reception and transmission are switched in a time division manner.

 [0024] 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. From the received signal, each mobile station device 12 The sample value related to the baseband OFDM signal is separated and extracted. That is, the signal input from the adaptive array antenna 20 is subjected to space division multiplexing (SDMA), time division multiplexing (TDMA), and orthogonal frequency division multiplexing (OFDMA). After the signal is amplified and down-converted, space division processing and time division processing relating to weight control of the adaptive array antenna 20 are performed. Next, symbol synchronization and guard interval (GI) signal removal 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.

 [0025] The FFT unit 24 performs an FFT on the sample value input from the receiving unit 22, and acquires each subcarrier component of the OFDM symbol.

[0026] Composite section 26 combines (combines) each subcarrier component of the OFDM symbol input from FFT section 24 for each predetermined number of subcarriers to generate a symbol string, and decodes the symbol string Thus, the received data from each mobile station apparatus 12 is acquired. Each reception data obtained in this way is output to a host device (not shown). [0027] 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 composite unit 26 combines the OFDM symbols for each subcarrier of 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 adjacency determination unit 30 described later (selection by the adjacent channel selection unit 40), at least two subchannels (hereinafter referred to as “allocation channels”) assigned by the channel allocation unit 32 to each mobile station apparatus 12 are determined. If it is determined that there are two or more subchannels adjacent to each other in the frequency direction, OFDM is also applied to subcarriers in each guard band provided between each of the two or more subchannels. Symbols are combined to generate a symbol sequence for each guard band. 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 the subcarrier in each guard band.

 [0028] FIG. 5 (a) is a diagram illustrating an example of transmission / reception data related to only a sub-channel. As shown in the figure, conventionally, even when two or more subchannels adjacent to each other in the frequency direction among the allocated channels exist, a guard band is uniformly provided between the subchannels. As mentioned above, in the case of power, it is extremely rare for adjacent channel interference to occur, resulting in loss of communication bandwidth by the guard band! /.

 On the other hand, FIG. 5 (b) is a diagram showing an example in which transmission / reception data related to guard bands is further added to transmission / reception data related to subchannels in the present 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 system is provided between these subchannels. Because the guard band provided is used as the communication band, the transmission area (payload) can be increased by the extension shown in Fig. 5 (b) compared to the conventional case, and the data transmission speed can be improved with S .

 [0030] The control unit 28 includes a reception unit 22, an FFT unit 24, a composite unit 26, a distribution unit 34, an IFFT unit 36, and a transmission unit.

38, etc., and controls the entire base station apparatus 10. For example, the sub-channel frequency and transmission / reception timing in the receiving unit 22 and the transmitting unit 38, the FFT unit 24 This controls the FFT execution timing, calculation target range, and the composite timing of received data in the composite section 26. Further, 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 with a CPU (Central Processing Unit) and a memory, and the above functions are performed by the CPU executing various control programs stored in the memory. Realized.

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 or not there are two or more sub-channels adjacent to each other in the frequency direction among at least two sub-channels that are detrimental to the mobile station apparatus 12) and any other sub-channel related to the allocated channel among the allocated channels Whether there is a subchannel that is not adjacent in the frequency direction, and there is an empty subchannel (subchannel that is not used for communication) adjacent to one of the assigned subchannels in the frequency direction. Whether or not is judged.

 [0032] In response to a link establishment request from each mobile station apparatus 12, channel allocating unit 32 selects one ASCH to be allocated to mobile station apparatus 12 from among 108 subchannels, and each mobile station apparatus In response to an ESCH allocation request from the device 12 or a terminal incoming call request from the network to which the base station device 10 is connected, one of the 107 subchannels excluding the ASCH is allocated to the mobile station device 12 1 or Select multiple ESCHs. 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 assigned to the mobile station devices a, b, and c by the channel allocating unit 32, and the others indicate empty subchannels.

[0033] Further, the channel allocation unit 32 allocates 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 channel accordingly. The process of changing the allocated channel for each mobile station apparatus 12 according to the subchannel allocation status will be described later. [0034] Adjacent channel selection section 40 selects two or more subchannels adjacent in the frequency direction among the allocation channels for each mobile station apparatus 12 according to the subchannel allocation status by channel allocation section 32. Is. For example, if the subchannel allocation status for mobile station device b is the status shown in FIG. 6 (a), adjacent channel selection unit 40 sets two channels surrounded by bold lines among the allocation channels for mobile station device b. A subchannel for

[0035] The non-adjacent channel selection unit 42 relates to each mobile station apparatus 12 according to the allocation channel among the allocation channels for each mobile station apparatus 12 according to the subchannel allocation status by the channel allocation unit 32. A subchannel that is not adjacent to any other subchannel in the frequency direction (hereinafter referred to as “non-adjacent channel”) is selected. For example, if the subchannel allocation status for mobile station apparatus b is the status shown in FIG. 6 (a), non-adjacent channel selection unit 42 selects the same channel (b Select the five sub-channels surrounded by the bold lines shown in).

 [0036] The adjacent vacant channel selection unit 44, depending on the subchannel allocation status by the channel allocating unit 32, vacant subchannels adjacent to one of the subchannels related to the allocated channel for each mobile station device 12 in the frequency direction ( In the following, “adjacent free channel” is selected. For example, when the subchannel allocation status related to mobile station apparatus b is the status shown in FIG. 6 (a), adjacent free channel selection unit 44 determines whether any of the subchannels related to the allocation channel for mobile station apparatus b Two empty subchannels surrounded by the thick line shown in Fig. 3 (c) are selected as adjacent empty subchannels in the frequency direction. Note that the free subchannels here are not only subchannels that are not used for communication at that time, but also immediately after subchannel allocation changes related to other mobile station apparatuses 12 ( For example, in the next TDMA frame, it may be a subchannel that is scheduled to be no longer used for communication.

[0037] Next, processing in which the channel allocating unit 32 changes the allocated 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, it is selected by the non-adjacent channel selection unit 42. Instead of the subchannel (non-adjacent channel) to be selected, one of the free subchannels (adjacent free subchannels) selected by the adjacent free channel selection unit 44 is allocated to each mobile station apparatus 12.

 [0038] For example, when the subchannel allocation status related to mobile station apparatus b is the status shown in Fig. 6 (a), as described above, non-adjacent channel selection section 42 uses the thick line shown in Fig. 6 (b). Five subchannels surrounded by are selected as non-adjacent channels. Also, the adjacent empty channel selection unit 44 selects two empty subchannels surrounded by bold lines 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. If each of the two empty subchannels surrounded by the bold line shown in Fig. 2 is assigned, the subchannel assignment status is as shown in Fig. 3 (d). That is, among the assigned channels for mobile station apparatus b, the number of subchannels adjacent in the frequency direction is increased by one set compared to the case of FIG. Thus, by increasing the number of subchannels adjacent in the frequency direction, more guard bands can be used as communication bands, and the data transmission rate can be further improved.

[0039] 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, and separates the obtained symbol string into subcarrier components. , Output to IFFT section 36. 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 allocated to the mobile station apparatus 12. Distribute to each subcarrier of the channel. In addition, 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 the communication band, so that the composite band is used. Similar to unit 26, the transmission area (payload) can be increased by the extension shown in Fig. 5 (b) compared to the conventional case, and the data transmission speed can be improved.

 [0040] IFFT section 36 performs IFFT on each subcarrier component of the OFDM symbol input from distribution section 34, and sequentially outputs the obtained signals to transmission section 38.

 [0041] The transmission unit 38 is configured to include a D / A converter, a time division multiplexing processing unit, a space division multiplexing processing unit, an up converter, and an amplifier. A-convert and obtain baseband OFDM signal. Next, a guard interval signal is added to the baseband OFDM signal to generate a signal that has been subjected to time division multiplexing processing and space division multiplexing processing relating to weight control of the adaptive array antenna 20. Then, the generated signal is up-converted to a radio signal, amplified to the transmission output level, and

Next, each functional block of the mobile station apparatus 12 will be described. As shown in FIG. 2, an antenna 50, a receiving unit 52, an FFT unit 54, a composite unit 56, a control unit 58, a distributing unit 64, an IFFT unit 66, and a transmitting unit 68 are configured. The receiving unit 52, FFT unit 54, combining unit 56, distributing unit 64, IF T unit 66, transmitting unit 68 are the receiving unit 22, FFT unit 24, combining unit 26, distributing unit 34, IFFT in the base station apparatus 10. Since it is almost the same as the unit 36 and the transmission unit 38 except for the processing related to space division multiplexing and time division multiplexing, detailed description is omitted here.

 [0043] The control unit 58 includes a reception unit 52, an FFT unit 54, a composite unit 56, a distribution unit 64, an IFFT unit 66, and a transmission unit.

 68 and the like, and controls the entire mobile station apparatus 12. For example, it controls the subchannel frequency and transmission / reception timing in the reception unit 52 and the 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. 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. Note that the control unit 58 is configured with a CPU and a memory as a center, and the above functions are realized by the CPU executing various control programs stored in the memory.

[0044] 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. [0045] The adjacent channel selection unit 62 is adjacent to the frequency direction among the at least two subchannels allocated from the base station apparatus 10 according to the subchannel allocation status managed by the channel management unit 60. It is a functional block that selects two or more subchannels and corresponds to the adjacent channel selection unit 40 in the base station apparatus 10.

 Here, the operation of base station apparatus 10 will be described. FIG. 7 is a flowchart showing a process of changing the allocated channel for 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, depending on whether or not the reception quality is equal to or higher than the predetermined quality, it is determined whether or not the allocation channel for the mobile station apparatus 12 can be changed (S100).

 [0048] When the reception quality is equal to or higher than the predetermined quality in S100, the non-adjacent channel selection unit 42, among the allocation channels for the mobile station device 12, according to the subchannel allocation status by the channel allocation unit 32, A subchannel (non-adjacent channel) that is not adjacent in the frequency direction to any other subchannel related to the assigned channel is selected (S102). If the reception quality is less than the predetermined quality in S100, the base station device 10 determines that the channel to be assigned to the mobile station device 12 cannot be changed, and does not change the assigned channel! /, .

 [0049] When at least one non-adjacent channel is selected in S102, the adjacent empty channel selection unit 44 relates to the allocation channel for 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 any subchannel in the frequency direction is selected (S104). If a non-adjacent channel is not selected in S102, base station apparatus 10 does not change the assigned channel.

[0050] When at least one adjacent free channel is selected in S104, channel allocating section 32 replaces the non-adjacent channel selected in S102 with any of the adjacent free channels in the mobile station apparatus 12 (S106). Then, MAP information, which is a 108-bit bit string indicating a new allocation channel, is generated and transmitted to the mobile station apparatus 12. (S108). If an adjacent free 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 the base station apparatus 10 changes the assigned channel. Not performed.

 [0051] According to the embodiment, when there are two or more subchannels adjacent to each other in the frequency direction among at least two subchannels used for communication, they are provided between the subchannels. The use of the guard band is also used for communication, so the frequency utilization efficiency can be improved and the data transmission speed can be improved.

 [0052] It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above description, the power of applying the present invention to a mobile communication system using both SDMA, TDMA, and OFDMA. In the present invention, a plurality of subchannels using a multicarrier transmission method are arranged in the frequency direction to It is widely applicable to mobile communication systems that realize connection.

Claims

The scope of the claims  [1] including a base station apparatus that communicates by a frequency division multiple access method using a plurality of subchannels and a plurality of mobile station apparatuses,  The base station apparatus includes channel allocating means for allocating at least two subchannels to the mobile station apparatuses as allocation channels,  Each mobile station apparatus is a mobile communication system that communicates with the base station apparatus using the allocated channel,  A guard band having a predetermined width is provided between the subchannels adjacent in the frequency direction,  The base station device  A first adjacent channel selection means for selecting two or more subchannels adjacent in the frequency direction among the allocated channels;  Using the guard band provided between each of the two or more sub-channels selected by the first adjacent channel selection means to communicate with each mobile station device;  Each of the mobile station devices is  A second adjacent channel selection means for selecting two or more subchannels adjacent in the frequency direction among the allocated channels;  Using the guard band provided between each of the two or more subchannels selected by the second adjacent channel selection means to communicate with the base station apparatus;  A mobile communication system. [2] In the mobile communication system according to claim 1,  The base station device Among the allocated channels, non-adjacent channel selection means for selecting a subchannel that is not adjacent to any other subchannel related to the allocated channel in the frequency direction; and any subchannel related to the allocated channel in the frequency direction Adjacent empty channel selection means for selecting adjacent empty subchannels; Further including  The channel allocating means allocates one of the free subchannels selected by the adjacent free channel selecting means to each mobile station device instead of the subchannel selected by the non-adjacent channel selecting means.  A mobile communication system. [3] In 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. [4] 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 method using a plurality of subchannels.  A guard band having a predetermined width is provided between the subchannels adjacent in the frequency direction,  Including adjacent channel selection means for selecting two or more subchannels adjacent to each other in the frequency direction among the at least two subchannels used for communication with each mobile station device,  Using the guard band provided between each of the two or more sub-channels selected by the adjacent channel selection means to communicate with each mobile station device;  A base station apparatus. [5] A mobile station apparatus that communicates with a base station apparatus using at least two subchannels according to a frequency division multiple access scheme using a plurality of subchannels,  A guard band having a predetermined width is provided between the subchannels adjacent in the frequency direction, The adjacent channel selection unit includes an adjacent channel selection unit that selects two or more subchannels adjacent to each other in the frequency direction among the at least two subchannels used for communication with the base station apparatus. More than one subchannel each A mobile station apparatus that performs communication with the base station apparatus by further using the guard band provided between them.  A multi-carrier communication method in a communication device that communicates with another communication device using at least two sub-channels by a frequency division multiple access method using a plurality of sub-channels,  A guard band having a predetermined width is provided between the subchannels adjacent in the frequency direction,  An adjacent channel selection step of selecting two or more subchannels adjacent in the frequency direction among the at least two communication channels used for communication with the other communication device;  Further using the guard band provided between each of the two or more sub-channels selected in the adjacent channel selection step to communicate with the other communication device;  A multi-carrier communication method.