JP2013179651A - Communication apparatus and communication system by multicarrier transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve utilization efficiency of a frequency, in a communication system for performing communication by a multicarrier transmission system between a plurality of communication apparatuses (10 and 20).SOLUTION: By dividing all frequency bands allocated to a communication system into a plurality of frequency bands (band 1 to band 4, for instance) of fixed band width respectively and transmitting usage frequency band information using a specified band (band 1, for instance) among the divided bands, allocation of remaining bands (band 2 to band 4) to be used between communication apparatuses is determined. In this case, the specified band is a main band for transmitting data channel information in addition to control channel information including the usage frequency band information, and an extension band for transmitting the additional data channel information can be added to the main band. Further, for the main band and the extension band, the frequency band to be used can be changed or the number of the frequency band can be increased or decreased with the passage of time.

Description

  The present invention relates to a communication system for exchanging information (data) between communication apparatuses by a multicarrier transmission system using a series of subcarriers, and more particularly to a communication apparatus accommodated in the communication system.

  One of the most suitable examples of the communication system discussed in the present invention is a mobile communication system, and the following description will be given by taking this mobile communication system as an example. Therefore, according to this example, the communication device is (i) a base station (or a higher-level base station control device) and (ii) a mobile station (including a mobile terminal such as a PDA). For convenience, in the following description, the former (i) may be referred to as “base station” and the latter (ii) may be simply referred to as “terminal”. However, as will be apparent from the following description, the present invention is applicable not only to the base station but also to the terminal, and it is not necessary to distinguish between the two.

  In a mobile communication system, securing a required transmission rate for a user is a big problem in providing the service. On the other hand, since the frequency band used by the mobile communication system is usually fixed for each system, even if user multiplexing is adopted, the maximum transmission rate is limited. For this reason, a method of flexibly changing the above-described use frequency band according to a required transmission rate has been studied.

  Further, when considering the entire mobile communication system, there is a problem in that the use situation differs for each of the above-mentioned use frequency bands, and sometimes the band is not used at all. For this reason, from the viewpoint of effective use of frequency, it has been studied to make the used frequency band variable.

  Under such circumstances, there has been proposed a technique for changing the frequency band used in a multi-carrier transmission mobile communication system such as MC (Multi-Carrier) -CDMA (Code Division Multiple Access) or OFDM (Orthogonal Frequency Division Multiplex). ing. For example, methods disclosed in the following four patent documents 1 to 4 have been proposed. The details will be described later with reference to the drawings. The outline of each will be described below.

  1) The “multiple access method and apparatus” disclosed in Patent Document 1 is characterized in that a used frequency band is freely allocated to a user by dividing a series of subcarriers.

  2) The “mobile station, base station apparatus and mobile communication network” disclosed in Patent Document 2 is characterized in that a subcarrier band dedicated to control signal transmission is set in the communication network.

  3) The “channel allocation method” disclosed in Patent Document 3 is characterized in that the number of a series of subcarriers is increased or decreased in accordance with the length of the communication distance between the base station and the mobile station.

  4) The “radio transmission apparatus and radio communication method” disclosed in Patent Document 4 is characterized in that the bandwidth of the used frequency band is made variable by changing the bandwidth of each subcarrier in a series of subcarriers. To do. The above-mentioned patent documents are as follows.

JP-A-9-205411 JP 2003-264524 A JP 2004-214746 A JP 2002-330467 A

  The conventional techniques based on the four patent documents 1 to 4 described above have the following problems.

  1) Since Patent Document 1 (Japanese Patent Laid-Open No. 9-205411) does not transmit information on subcarriers to be used, it is inefficient because the receiving side needs to receive and decode all subcarriers.

  2) In Patent Document 2 (Japanese Patent Application Laid-Open No. 2003-264524), information about subcarriers to be used is transmitted. However, a common control channel for transmitting the subcarrier information must be received, and further demodulation and Decryption is required.

  In addition, when user multiplexing is performed, information required by the user must be extracted from data transmitted through the common control channel. Furthermore, since information for each user enters the common control channel, there is a possibility that the bandwidth will be insufficient at a low transmission rate. Furthermore, since it is a common control channel common to all users, changing the subcarrier to be used affects all users. Therefore, the subcarrier of the common control channel cannot be changed easily.

  3) In Patent Document 3 (Japanese Patent Laid-Open No. 2004-214746), although the bandwidth of the data channel is variable, the common control channel still uses a fixed frequency band common to all users. There is a problem similar to Document 2.

  4) When considering the use of user multiplexing in Patent Document 4 (Japanese Patent Laid-Open No. 2002-330467), it is necessary to further perform code multiplexing between users in order to keep interference due to transmission of a large number of users low. However, if the bandwidth of the subcarrier differs among users for this reason, the degree of orthogonality of the code deteriorates and eventually causes interference.

  In order to prevent this interference, when a user changes the bandwidth of a subcarrier, other users must change the bandwidth of the subcarrier accordingly. As a result, the bandwidth of the subcarrier is continuously widened by being dragged by a user having a poor propagation condition, and the transmission efficiency is lowered. Therefore, there is an inconvenience that changing the bandwidth of the subcarrier is sometimes not an effective means.

  Therefore, in view of the above problems, the present invention can easily expand, reduce, or change the frequency band used by each user within the entire frequency band assigned to the communication system, An object of the present invention is to provide a communication system (mobile communication system) in which expansion, reduction, or change does not affect other users, particularly a communication apparatus (base station and / or terminal) therefor. .

  According to the present invention, as will be described in detail later with reference to the drawings, a specific frequency band is first set out of a plurality of frequency bands obtained by dividing the entire frequency band assigned to the communication system. Then, using the specific frequency band, “used frequency band information” that determines which of the remaining frequency bands should be used between the communication apparatuses is transmitted from one communication apparatus to the other communication apparatus. Furthermore, the specific frequency band is set as a “main band” in all the frequency bands described above. This main band transmits "data information (user data)" in addition to the above "used frequency band information". Furthermore, at least one frequency band set from the frequency bands excluding the “main band” among the plurality of frequency bands described above is set as an “extension band”. This extension band is mainly used for transmitting further data information and can cope with an increase in the amount of data. Therefore, this extended band is set as necessary. However, the main band is always set at the time of establishment of the radio line, and not only the above “use frequency band information” but also the original “data information within the range allowed by the transmission capacity by this main band. ”(User data). Further, general “control information” (user control information) may be included in this main band. This solves the above problems.

It is a figure which shows the basic composition of the communication apparatus (transmission side) based on this invention. It is a figure which shows the basic composition of the communication apparatus (receiving side) based on this invention. It is a figure which shows one specific example of the communication apparatus (transmission side) 10 based on this invention. It is a figure which shows one specific example of the communication apparatus (reception side) 20 based on this invention. It is a figure which shows the modification of the communication apparatus (transmission side) 10 based on this invention. It is a figure which shows the modification of the communication apparatus (reception side) 20 based on this invention. It is a figure which shows the other modification of the communication apparatus (transmission side) 10 based on this invention. It is a figure which shows the other modification of the communication apparatus (reception side) 20 based on this invention. It is a figure which shows the mode of the frequency division in a communication system. It is a figure which shows a mode that the "main band" and the "extension band" were selected one each. It is a figure which shows the 1st example of the allocation aspect of the main band with respect to multiple users. It is a figure which shows the 2nd example of the allocation aspect of the main band with respect to multiple users. It is a flowchart which shows an example which changes the frequency band of a main band dynamically. FIG. 14A is a diagram (part 1) illustrating an example of a device configuration on the pilot signal transmission side. FIG. 14B is a diagram (part 2) illustrating an example of a device configuration on the pilot signal transmission side. FIG. 15A is a diagram (part 1) illustrating an example of a device configuration on the return side of response (CQI) information to a pilot signal. FIG. 15B is a diagram (part 2) illustrating an example of a device configuration on the return side of response (CQI) information to a pilot signal. It is a figure which shows the 1st multiplexing example of a pilot signal. It is a figure which shows the 1st multiplexing example of a pilot signal. It is a figure which shows the example of a dynamic change of a main band clearly. It is a flowchart which shows the 1st example of introduction and a change of an expansion band. It is a flowchart which shows the 2nd example of introduction and change of an expansion band. It is a flowchart which shows the 3rd example of introduction and change of an extension band. It is a figure which shows the example of a dynamic change of an expansion band clearly. It is a flowchart which shows an example which changes both the main band and an expansion band. It is a flowchart which shows the example of a dynamic change of both the main zone | band and an expansion zone in an easy-to-understand manner. It is a figure which shows the example of an apparatus structure at the side of the response of the response with respect to a pilot signal (CQI) information. It is a figure which shows the table | surface for demonstrating the highly efficient transmission of use frequency band information. It is a figure which shows the example of a dynamic change of an expansion band. It is a figure which shows the 1st example of a band expansion pattern. It is a figure which shows the 2nd example of a band expansion pattern. It is a figure which shows the 3rd example of a band expansion pattern. It is a figure which shows the apparatus structural example of the communication apparatus (transmission side) which concerns on Embodiment 10. FIG. 32 is a flowchart showing an operation example in the apparatus of FIG. 31. It is a figure for demonstrating the embodiment 11. FIG. It is a figure showing the principal point of the prior art disclosed by patent document 1. FIG. It is a figure showing the principal point of the prior art disclosed by patent document 2. FIG. It is a figure showing the principal point of the prior art disclosed by patent document 3. FIG. It is a figure showing the principal point of the prior art disclosed by patent document 4.

  First, the prior art (Patent Documents 1 to 4) described above will be described with reference to the drawings in order to facilitate understanding of the present invention.

  FIG. 34 is a diagram showing the main points of the prior art disclosed in Patent Document 1. In FIG. This figure shows, for example, frequency assignments for seven users U1 to U7 (upper stage), and the lower part shows a series of subcarrier assignments in detail for users U1 and U2. The horizontal axis is frequency.

  This system is characterized in that a plurality of carriers are continuously arranged in a frequency band allocated on the transmission side, and a plurality of subcarriers are divided and continuously arranged according to users (U1 to U7). .

  Specifically, for example, the total frequency band that can be used in one communication system is 20 MHz, and 250 subcarriers are set therein. Therefore, the bandwidth of each subcarrier is 20 [MHz] / 250 = 80 [kHz]. These 250 subcarriers are dynamically allocated and used among a plurality of users (U1 to U7).

  At this time, for example, the number of used subcarriers is made variable by dynamically allocating 50 for user A (U2) and 75 for another user B (U1).

  Accordingly, the use frequency band is 50 × 80 [kHz] = 4 [MHz] for user A and 75 × 80 [kHz] = 6 [MHz] for user B, and the use frequency band is variable for each user. Is done. In this case, the assigned subcarriers are assumed to be continuous on the frequency axis. It is also possible to make the frequency band division width variable.

  FIG. 35 is a diagram showing the main points of the prior art disclosed in Patent Document 2. This figure is a diagram showing how common control channels and data channels are allocated on the frequency axis.

  This system is a multi-carrier CDMA system in which subcarriers dedicated for control signal transmission and subcarriers dedicated for data transmission (data channel) are set separately. The common control channel is spread by a unique spreading code. Therefore, when receiving this common control channel, it is only necessary to demodulate a specific subcarrier, and the amount of signal processing can be reduced.

  FIG. 36 is a diagram showing the main points of the prior art disclosed in Patent Document 3. This figure shows that the frequency band of the data channel in FIG. 35 is made variable according to the propagation distance (communication distance to the base station). However, the transmission power is also changed (large-medium-small).

  This system is a system that realizes variable speed communication by fixing the transmission rate per subcarrier and changing the number of subcarriers allocated to the user, and the distance between the base station and the terminal is When the distance is close, many subcarriers are allocated while reducing the transmission power of each subcarrier, and when the distance is long, a small number of subcarriers is allocated while increasing the transmission power of each subcarrier.

  Further, while a small number of subcarriers are used for the common control channel, a large number of subcarriers are allocated to the data communication channel (data channel), and the two are completely separated on the frequency axis. Note that the base station notifies the mobile station of the center subcarrier number of the subcarrier allocated for the data channel and the number of subcarriers to be used, using the subcarrier dedicated for the common control channel.

  FIG. 37 is a diagram showing the main points of the prior art disclosed in Patent Document 4. This figure shows that the bandwidth of each subcarrier is made variable according to the quality of the propagation environment.

  This system changes the bandwidth of each subcarrier while keeping the total number of subcarriers constant according to the state of the propagation environment in wireless transmission. For example, when the propagation state becomes worse, the bandwidth of each subcarrier is widened. Thereby, since transmission can be performed without changing the total subcarriers, the transmission rate can be kept constant regardless of the propagation environment.

  The present invention solves the above-mentioned various problems of the prior art (Patent Documents 1 to 4) described with reference to FIGS. 34 to 37, and will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing a basic configuration of a communication apparatus (transmission side) based on the present invention.
FIG. 2 is a diagram showing a basic configuration of a communication apparatus (reception side) based on the present invention.

  In FIG. 1, reference numeral 10 indicates a communication apparatus (transmission side), and in FIG. 2, reference numeral 20 indicates a communication apparatus (reception side), which are accommodated in the same communication system (mobile communication system). As described above, the communication device 10 may be a base station and the communication device 20 may be a terminal, or vice versa. The present invention can be applied to either, but for easier understanding, Unless otherwise stated, it is assumed that the communication device 10 on the transmission side is a base station, and the communication device 20 on the reception side is a terminal.

  First, referring to FIG. 1, the use frequency band to be used with the counterpart communication device 20 is selected using the selection function of the use frequency band selection / setting unit 15. “Used frequency band information” If (frequency) based on this selection is input to the transmission data generating unit 11, where transmission integrated with transmission data (user data) Du (user) to be transmitted to the communication device 20. Data Dt (transmission) is generated. Therefore, the transmission data Dt includes transmission data Du and use frequency band information If, but actually includes other “communication control information” Ict (control). This information Ict is, for example, information relating to a modulation scheme used such as QAM, and is information relating to the amount of transmission data for one transmission data Du.

  The transmission data Dt is input to the next-stage multicarrier transmission transmission processing unit 13 after predetermined modulation is applied by the modulation unit 12. The processing unit 13 is applied with a band setting instruction signal Sb (band) instructing that transmission processing should be performed in the selected use frequency band by the setting function of the use frequency band selection / setting unit 15. The processing unit 13 performs signal transmission processing conforming to multicarrier transmission in the frequency band based on the signal Sb.

  Further, the radio unit 14 performs frequency conversion on the transmission data signal St from the processing unit 13 and transmits it to the counterpart communication device (terminal) 20 from the antenna AT at the next stage.

  On the other hand, referring to FIG. 2, a radio signal from the antenna AT (FIG. 1) is received by the antenna AT (FIG. 2), and is further frequency-converted by the radio unit 21 to be a received data signal Sr. Input to the reception processing unit 22. The processing unit 22 performs signal reception processing conforming to multicarrier transmission on the received data signal Sr, and the demodulating unit 23 in the next stage demodulates the signal after the signal reception processing.

  The demodulated reception data Dr is decoded by the reception data decoding unit 24 and separated into the original transmission data Du and the previously used frequency band information If set previously. Further, the communication control information Ict described above is also separated from the data Dr. Note that the portion controlled by this information Ict is not directly related to the essence of the present invention, and is omitted.

  The original used frequency band information If obtained by separating from the received data Dr as described above is input to the used frequency band setting unit 25. The setting unit 25 receives the information If and reproduces the band setting instruction signal Sb described above. The signal Sb is applied to the multicarrier transmission reception processing unit 22 described above, and the processing unit 22 performs signal reception processing conforming to multicarrier transmission in the frequency band selected on the transmission side. Note that a predetermined frequency band may be selected at the beginning of the establishment of the wireless line.

  In the present invention, the transmission side (10) and the reception side (20) can use the same use frequency band by the band setting instruction signal Sb described above. Further, based on the signal Sb, the used frequency band can be expanded, reduced, or changed simultaneously on both the transmitting side (10) and the receiving side (20). Thus, the object of the present invention described above can be achieved.

  The basic configuration of the present invention described above will be described more specifically while comparing with the above-described conventional technology.

  In the present invention, the frequency band that can be used in the entire communication system is divided into a plurality of bands. For example, when the use frequency band of the entire communication system is set to 20 [MHz], one band is set to 5 [MHz] and is divided into four. Using this one band 5 [MHz], each information of a control channel for transmitting use frequency band information and a transmission channel (data channel) for transmitting transmission data is transmitted.

  According to the present invention, as described above, at least the frequency band for transmitting the control channel is a “main band”, and the further expanded frequency band is an “extended band”. For example, in the case of an OFDM communication system, one subband 5 [MHz] includes 100 subcarriers, and the bandwidth of each subcarrier is 50 [kHz]. Each information of a control channel and a data channel is transmitted using a carrier. The multiplexing method of both information may be time multiplexing, frequency multiplexing or spreading code multiplexing.

  As described above, unlike Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-214746), since the information on the “main band” is received and decoded, the used frequency band (or the number of used frequency bands) is known. Bandwidth can be easily expanded, reduced or changed. This also simplifies the configuration of the receiving unit, unlike Patent Document 1 (Japanese Patent Laid-Open No. 9-205411) and Patent Document 3 (Japanese Patent Laid-Open No. 2004-214746).

  If the number of subcarriers per frequency band is constant, the number of subcarriers changes at an integer ratio as the number of frequency bands used is changed. Therefore, the configuration of the receiving unit is simplified as compared with Patent Document 3 (Japanese Patent Laid-Open No. 2004-214746) in which the subcarrier dynamically changes.

  In addition, by designating the use frequency band from the base station to the terminal in advance, the extension band can be easily changed and added, and the main band can also be changed.

Furthermore, if the bandwidth of each subcarrier is fixed as described above, the use frequency band is changed without affecting other users as in Patent Document 4 (Japanese Patent Laid-Open No. 2002-330467). be able to. Various embodiments based on the present invention will be described below.
[Embodiment 1: Setting of use frequency band]
First, some characteristics disclosed in the first embodiment will be described as follows. The main points of this feature are as already described, and are the following three points (i) to (iii).

  (I) A specific frequency band is set from a plurality of frequency bands obtained by dividing the entire frequency band allocated to the communication system, and any remaining frequency band is set as a communication device using the specific frequency band. Transmitting “used frequency band information” If that defines whether or not to use each other (10, 20), and (ii) setting the specific frequency band as the “main band” of all frequency bands. The main band transmits data information (Du) in addition to the used frequency band information If. (Iii) Of the plurality of frequency bands, the frequency band excluding the “main band” The at least one frequency band set from the above is defined as an “extension band”, and this extension band is mainly for transmitting further data information (Du).

  And some important points further disclosed in the present embodiment 1 are the following four points (iv) to (vii).

(Iv) The above-mentioned “main band” is fixedly set when a wireless line is established between communication devices (10, 20),
(V) When there are a plurality of communication devices (20), a “main band” is individually set for each of the plurality of frequency bands, and each of the plurality of communication devices (20) is associated with each of the main devices. To allocate bandwidth,
(Vi) Two or more communication devices (20) use the same “main band” simultaneously by time multiplexing and / or spreading code multiplexing,
(Vii) Also, the number of extension bands is increased or decreased according to the required transmission rate of the data information (Du).

FIG. 3 is a diagram showing a specific example of the communication device (transmission side) 10 according to the present invention.
FIG. 4 is a diagram showing a specific example of the communication device (reception side) 20 according to the present invention. Throughout the drawings, similar components are denoted by the same reference numerals or symbols. The specific examples shown in FIGS. 3 and 4 are commonly applied not only to the first embodiment but also to other embodiments 2 to 10 described later.

  First, referring to the communication apparatus (transmission side) 10 in FIG. 3, the components corresponding to the components 11 to 15 and Du, Dt, St, and Sb shown in FIG. Du, Dt, St, and Sb are attached.

  The transmission data generation unit 11 includes a data block creation unit 31, an encoding unit 32, a transmission data amount calculation unit 33, an encoding unit 34, and a multiplexing unit (Mux) 35 according to the example shown in FIG.

  Based on the use frequency band information If from the use frequency band selection / setting unit 15, the transmission data amount calculation unit 33 first calculates the transmission data length, and the data block creation unit 31 calculates the data block for each transmission data length. As a summary. Further, the encoding unit 32 encodes the transmission data using the transmission data length.

  The used frequency band information If is encoded by the encoding unit 34 together with the communication control information Ict indicating the modulation method to be used. Note that the encoding units 32 and 34 may encode Du and If together as a single encoding unit.

  The encoded outputs from both the encoding units 32 and 34 are multiplexed by a multiplexing unit (Mux) 35 to become the transmission data Dt described above. This data Dt is further modulated by the modulator 12 as described above. As a multiplexing method, there are frequency multiplexing using divided subcarriers, time multiplexing (for example, using the frame format shown in FIG. 16), spreading code multiplexing, and the like. Further, as a modulation method by the modulation unit 12, there are QPSK, 16QAM, 64QAM, and the like.

  Next, looking at the multicarrier transmission transmission processing unit 13, in the example shown in the figure, the multicarrier transmission transmission processing unit 13 is composed of components 36, 37, 38, 39 and 40. However, an example assuming communication using OFDM is shown. Another example based on MC-CDMA communication is shown in FIG. 7 (FIG. 8).

  The separation unit (DeMux) 36 separates information belonging to “main band” and information belonging to “extended band”. Information belonging to the “main band” is converted into a parallel signal by a serial / parallel converter (S / P) 37, and then subjected to time-frequency conversion on the parallel signal by an inverse fast Fourier transformer (IFFT) 38. . The parallel signal converted to this frequency is converted again into a serial signal by a parallel / serial conversion unit (P / S) 39. Further, a guard interval (GI) insertion unit 40 inserts a guard interval GI for preventing intersymbol interference in the serial signal.

  The transmission data signal St thus obtained is input to the radio unit 14. According to the example shown in the figure, the radio unit 14 includes a general mixer 41, a local oscillator 42, and a power amplifier 44 (D / A converter, filter, etc. are omitted), and the transmission data signal St is received from the antenna AT. Send it out. In this case, the adding unit 43 is provided in the middle.

  As described above, the adding unit 43 applies the “main” by the above-described components 37, 38, 39, 40, 41, and 42 to the information belonging to the “extended band” separated by the separating unit (DeMux) 36. The processing similar to the processing for “band” is performed by the components 37 ′, 38 ′, 39 ′, 40 ′, 41 ′ and 42 ′ to obtain the transmission data signal St on the “extended band” side. The transmission data signal St on the “main band” side is integrated.

  The transmission data on the “extended band” side is generated only when data transmission by the “extended band” is required. Whether or not the transmission data is necessary depends on the band from the selection / setting unit 15 described above. It is determined by the inside of the setting instruction signal Sb.

  Next, referring to FIG. 4, the portions corresponding to the components 21 to 25 and Sr, Dr, Du, If, and Sb shown in FIG. 2 are denoted by these reference numbers and symbols 21 to 25 and Sr, Dr, Du. , If, Sb.

  According to the example of this figure, the radio unit 21 removes an unnecessary band signal from the received signal from the antenna AT by the band-pass filter (BPF) 51, and converts it to a required reception frequency by the mixer 52 and the local oscillator 53. As a result, a received data signal Sr is obtained.

  The received data signal Sr is input to the multicarrier transmission reception processing unit 22 and processed. The processing unit 22 includes constituent elements 54, 55, 56, 57 and 58 shown in the figure.

  First, the guard interval (GI) removal unit 54 removes the guard interval inserted on the transmission side. The signal after GI removal is further converted into a parallel signal by a serial / parallel converter (S / P) 55, and a fast Fourier transform (FFT) 56 performs frequency-time conversion on the parallel signal. The time-converted parallel signal is converted again into a serial signal by a parallel / serial conversion unit (P / S) 57.

  On the other hand, when there is information belonging to the “extended band” in the received signal from the antenna AT, the signal of the “extended band” information is extracted by the mixer 52 ′ and the local oscillator 53 ′, and the above-described components 55 to 55 are extracted. The same processing as the processing by 57 is performed by the similar components S / P 55 ′, FFT 56 ′ and P / S 57 ′ to obtain a time-converted serial signal.

  Each serial signal from the parallel / serial converters 57 and 57 ′ is multiplexed by a multiplexer (Mux) 58 and further demodulated by a demodulator 23. When only the information belonging to the “main band” is transmitted, the multiplexing unit 58 does not perform multiplexing and simply passes the signal.

  The signal from the multiplexing unit 58 becomes the reception data Dr demodulated by the demodulation unit 23 at the next stage, and then is input to the reception data decoding unit 24. According to the example of this figure, the decoding unit 24 includes a separation unit (DeMux) 59, a data channel decoding unit 60, a control channel decoding unit 61, and a transmission data amount calculation unit 62.

  The separation unit 24 separates the received data Dr into data channel side data and control channel side data, and distributes them to the decoding unit 60 and the decoding unit 61, respectively. From the decoding unit 60, the original transmission data Du is reproduced based on the transmission data amount described later. On the other hand, the “use frequency band information” If is reproduced from the decoding unit 61.

  The information If from the decoding unit 61 is input to the transmission data amount calculation unit 62 on the one hand, where the data length of the received transmission data is calculated based on the If, and the decoding unit 60 performs the data length based on the data length. Decodes transmission data.

  On the other hand, the information If from the decoding unit 61 is supplied to the above-described use frequency band setting unit 25, where the band setting instruction signal Sb is generated. Then, the setting corresponding to the selected frequency band is performed for each circuit portion (22, 58, 59) through the dotted path shown in the figure depending on the content of the signal Sb. The reception data decoding unit 24 shown in FIG. 4 is configured such that after the reception data Dr is first input to one decoding unit (commonization of the decoding units 60 and 61) and decoded, the data channel is separated by the separation unit 59. And the control channel may be separated.

  3 and 4 described above, the frequency band of the “main band” is fixed, and only the frequency band of the “extension band” is variable. However, in an embodiment of the present invention, not only the “extension band” but also the “main band” can change the frequency band. A configuration example for realizing this is shown in the figure.

FIG. 5 is a diagram showing a modification of the communication device (transmission side) 10 according to the present invention.
FIG. 6 is a diagram showing a modification of the communication control apparatus (reception side) 20 based on the present invention.

  The difference between the configuration shown in FIGS. 5 and 6 and the configuration shown in FIGS. 3 and 4 is that the range indicated by the band setting instruction signal Sb from the use frequency band selection / setting unit 15 in FIG. , Not only on the “extended band” side (37 ′ to 42 ′) (in the case of FIG. 3) but also on the “main band” side (37 to 42). Further, in FIG. 6, the instruction range by the band setting instruction signal Sb from the use frequency band setting unit 25 is not only the “extended band” side (52 ′ to 57 ′) (in the case of FIG. 4), but the “main band” side. (52-57). Thus, it is possible to change the frequency band of the “main band”.

  Moreover, although the description of the above specific example was performed on the premise of communication by OFDM, it is also possible to presuppose communication by MC-CDMA. An example of a communication apparatus in the latter case (MC-CDMA base) is also shown here.

FIG. 7 is a diagram showing another modification of the communication device (transmission side) 10 according to the present invention.
FIG. 8 is a diagram showing another modification of the communication device (reception side) 20 according to the present invention.

  For example, when FIG. 5 and FIG. 6 described above are compared with FIG. 7 and FIG. 8, the configuration of the multicarrier transmission transmission processing unit 13 is different on the transmission side (10), and the multicarrier on the reception side (20). The configuration of the transmission / reception processing unit 22 is different.

  That is, the processing unit 13 shown in FIG. 7 is different in that a copier 46 and a multiplication unit 47 are used. Further, the processing unit 22 shown in FIG. 8 is different in that a multiplication unit 65 and a synthesis unit (Σ) 66 are used.

  First, the transmission operation will be described with reference to FIG. The generated transmission data is modulated and copied by the copier unit (Copier) 46 by the number of subcarriers. Multiplier 47 multiplies the copied signal by a spreading code (C1, C2... Cn). The IFFT unit (38, 38 ') performs IFFT on this result and performs time-frequency conversion. Subsequently, the GI insertion unit 40 inserts the GI, converts the frequency, and transmits it from the antenna AT. Further, the setting of the multicarrier transmission transmission processing unit 13 is changed based on the use frequency band selected by the use frequency band selection unit 15.

  Next, the reception operation will be described with reference to FIG. First, the received signal is frequency-converted to obtain a baseband signal, and the GI removal unit 54 removes the GI. Subsequently, serial / parallel conversion is performed (55, 55 ′), and the spreading code (C1, C2,... Cn) is multiplied and despread by the multiplication unit 65, respectively. The result is subjected to FFT in the FFT unit (56, 56 '), frequency-time conversion is performed, and then the sum is obtained in the synthesis unit 66. The result is demodulated by the demodulator 23. Thereafter, processing is performed in the same manner as described above to extract the use frequency band information If. Then, the setting of the multicarrier transmission reception processing unit 22 is changed based on the extracted use frequency band information If. 7 and 8, when changing the use frequency band, the number n of frequency spreading codes may be made variable. When MC-CDMA is used as described above, the apparatus configuration can be simplified as compared with OFDM. However, on the other hand, since it becomes necessary to dynamically change the number of points of FFT and IFFT, the control becomes complicated.

  Hereinafter, the first embodiment will be further described with reference to the frequency band arrangement configuration diagram.

  In a communication system that can change a used frequency band using OFDM or the like, the used frequency band information If is transmitted in a specific frequency band. The use band information If can be obtained by demodulating and decoding a specific frequency band. With this information If, communication in the extended band becomes possible. As a premise, in the present invention, the entire frequency band is divided as follows.

  FIG. 9 is a diagram showing a state of frequency division in the communication system. A series of subcarriers in this figure represents the entire frequency band allocated to the communication system. The entire frequency band is divided into a plurality of frequency bands. In the figure, an example of four divisions is shown, and division into four frequency bands, that is, “band 1”, “band 2”, “band 3”, and “band 4”. One of these “band 1” to “band 4” is selected as the “main band”, and another band is selected as the “extended band”.

  FIG. 10 is a diagram illustrating a state where “main band” and “extended band” are selected one by one. For example, the band 1 is selected as the “main band”, and the band 2 is selected as the “extended band”. As described above, the “main band” is allocated to the transmission of the control channel (CH) and the data channel (CH), and the “extended band” is allocated to the transmission of the further data channel. The main band used by a certain terminal is determined by, for example, a base station or a base station control apparatus at a higher level. Or conversely, the main band may be designated from the terminal side to the base station side.

  The main band may be fixed in advance as a communication system, or may be set when wireless communication is established between communication apparatuses (base station and terminal), and the setting may be fixed until the communication is completed.

  Furthermore, when there are a plurality of communication devices (user terminals), a different main band may be set for each user terminal. This is illustrated in the figure.

FIG. 11 is a diagram illustrating a first example of an allocation mode of main bands for a plurality of users.
FIG. 12 is a diagram illustrating a second example of an allocation mode of main bands for a plurality of users. This allocation mode can be applied to the extended band.

  First, referring to FIG. 11, the main bands of the users U1 to U4 are individually assigned to a plurality of frequency bands, that is, the bands 1 to 4, respectively. However, in this case, the number of users is limited by the number of bands.

  Therefore, as shown in FIG. 12, the same main band is simultaneously allocated to a plurality of communication devices (user terminals). This is possible by user multiplexing. As this multiplexing method, there are time multiplexing and spreading code multiplexing, or a combination of these.

  Furthermore, in the first embodiment, the use frequency band (band 1 to band 4) can be increased or decreased according to the required transmission rate of the data information (transmission data Du).

  That is, in the base station, the use frequency band is expanded when it is determined that another frequency band can be used in consideration of the communication status, propagation environment, use frequency band, and the like of other terminals that are communicating. Note that the frequency of use may be preferentially extended based on transmission data attributes (QoS: Quality of Service) such as communication priority between terminals and required transmission speed.

In this way, since the used frequency band information If is transmitted in a specific frequency band (main band), the receiving side only needs to receive the main band first, and receive and demodulate to other frequency bands. There is no need to decrypt. Further, by using the extension band, the transmission speed can be further increased, and the frequency utilization efficiency can be improved.
[Embodiment 2: Dynamic change of main band]
First, some characteristics disclosed in the second embodiment will be described as follows.

i) The frequency band that the main band should occupy among a plurality of frequency bands (band 1 to band 4) is made variable over time,
ii) Determining whether the propagation environment between the communication devices (10, 20) is good or not, and selecting the frequency band of the best propagation environment among the plurality of frequency bands or a frequency band equivalent thereto to set as the main band. And
iii) Notifying the other communication device in advance of the change of the frequency band when setting the new main band,
iv) using the detection result of the transmission quality (CQI) obtained in response to the transmitted pilot channel or pilot signal between the communication devices, to determine the quality of the propagation environment described above,
v) The determination of the quality of the propagation environment is performed sequentially or simultaneously for all of the plurality of frequency bands.
vi) In addition, the determination result of the quality of the propagation environment is transmitted to the counterpart communication device through a control channel in a specific frequency band.

  In general, the transmission quality of the control channel must be better than that of the data channel. First, it is necessary to securely set a line through which data is transmitted. That is, it is necessary to select a frequency band with a better propagation environment so that the main band including the control channel has better transmission quality than the extension band. Therefore, a specific example will be described in which the frequency band set as the main band is freely selected according to the quality of the propagation environment.

  FIG. 13 is a flowchart showing an example of dynamically changing the frequency band of the main band. The basic transmission / reception operation between the base station and the terminal is as described in the first embodiment. In FIG. 13, the solid line blocks represent the operation of the base station, and the dotted line blocks represent the operation of the terminal. However, this may be reversed (the same applies to other flowcharts described later).

  Step S11: A pilot channel signal is transmitted in each frequency band.

Step S12: receiving all pilot channel signals,
Step S13: Each SNR etc. is calculated and converted into CQI,
Step S14: Each CQI is transmitted on the uplink control channel.

Step S15: Receiving each CQI,
Step S16: Select a use frequency band, determine a band change timing,
Step S17: The selected use frequency band and the determined change timing are transmitted using the downlink control channel.

Step S18: Receiving the above used frequency band and the change timing,
Step S19: In accordance with the above change timing, the setting in each circuit unit is changed,
Step S20: The reception operation is started using the changed main band.

  The SNR is a Signal to Noise Ratio, and the CQI is a Channel Quality Indicator. The definition regarding CQI is described in TS25.212 Release 5 of 3GPP (3rd Generation Partnership Project http://www.3gpp.org/), and these specifications are also available at http: //www.3gpp. It is registered in org / ftp / Specs / html-info / 25-series.htm.

  The process for making the main band variable with time according to the flowchart shown in FIG. 13 as an example can be realized by the following apparatus configuration, for example.

14A and 14B are diagrams illustrating an example of a device configuration on the pilot signal transmission side,
FIGS. 15A and 15B are diagrams illustrating an example of a device configuration on the return side of response (CQI) information to a pilot signal.

  The configuration shown in FIGS. 14A and 14B is substantially the same as the configuration shown in FIG. 3 (or FIG. 5), and the elements to be newly noted are the pilot signal Sp (or pilot channel) at the left end of FIG. , A multiplexing unit (Mux) 71 that multiplexes the pilot signal Sp and the used frequency band information If, and a CQI extracting unit 72 in the lower half of the figure. The configuration of the lower half is substantially the same as the configuration of FIG. 4 (or FIG. 6) described above, and the component to be newly noted is the CQI extraction unit 72 on the lower center side of the figure. In the lower half of the figure, the corresponding parts in FIG. 4 are denoted by reference numerals 52, 53, 54... Used in FIG.

  The configuration shown in FIGS. 15A and 15B is the same as the configuration shown in FIG. 4 (or FIG. 6), and the components to be newly noted are the SNR measurement unit 75 and the CQI calculation unit 76 in the upper half of FIG. Further, the encoding unit 78 and the addition unit 79 in the lower half of the figure after passing through the return path 77. In the upper half of the figure, the corresponding parts in FIG. 4 (reception side) are indicated by the reference numerals 52, 53, 54... Used in FIG. Corresponding parts in the (transmission side) are indicated as 112, 137, 138, etc. by adding 100 to the reference numbers 12, 37, 38,... Used in FIG.

  The pilot signal Sp is transmitted after being multiplexed with other transmission information in actual operation. For example, there are the following two multiplexing methods.

FIG. 16 is a diagram illustrating a first multiplexing example of pilot signals,
FIG. 17 is a diagram illustrating a second multiplexing example of pilot signals. In both figures, “P” represents the pilot signal Sp, “C” represents the communication control information Ict described above, and “D” represents the transmission data Du described above.

  FIG. 16 shows that the pilot signal Sp is multiplexed in the time direction, while FIG. 17 shows that the pilot signal Sp is multiplexed in both the time direction and the frequency direction.

  FIG. 18 is a diagram showing an example of dynamic change of the main band in Embodiment 2 described above in an easily understandable manner. The passage of time goes from the top to the bottom of the figure. As the time elapses, the main band changes, for example, as “Band 1” → “Band 2” → “Band 1” → “Band 4” following a better propagation environment.

  As described above, the base station multiplexes a signal (pilot) for measuring the propagation environment and transmits it as a control channel in all operating frequency bands. In actual operation, it may be assumed that the transmission data Du is not included. A pilot channel may be provided instead of the pilot signal Sp.

  The terminal receives pilot channel signals for all frequency bands (band 1 to band 4), measures the reception status and propagation environment such as SNR and CIR (Carrier to Interference Ratio), for example, and determines the CQI from the measured values. Are transmitted to the base station sequentially or simultaneously for each band using the uplink control channel. The measurement results such as CIR and SNR may be transmitted as they are.

  The base station that receives the uplink control channel signal and demodulates and decodes the CQI selects the frequency band with the best CQI value from among a plurality of CQIs as the main band. The selection result and the change timing of the main band are transmitted on the downlink control channel to the terminal.

  The terminal receives this downlink control channel signal, demodulates and decodes it, and extracts information on the used frequency band and change timing. Subsequently, the use frequency band is changed in accordance with the change timing. The change timing may be determined by, for example, absolute time, relative time, or slot unit. Further, the change timing may not be transmitted, and the system may be fixed, for example, 5 slots after transmission of the downlink control channel signal.

  In the above description, the frequency band with the best propagation environment is selected as the main band. However, the best frequency band may not be selected depending on the situation of other terminals. In such a case, the second best frequency band corresponding to the above may be selected.

  Although the base station selects the main band here, the terminal may similarly select the frequency band with the best propagation environment and transmit it to the base station.

  As described above, measurement of SNR, CIR, and the like at the terminal may be performed simultaneously for each frequency band, or may be measured by time. In addition, the propagation environment does not change greatly under the condition that narrow bandwidths are continuous, and in such a case, only one frequency band may be measured. Moreover, the measured value is good also as an average value after measuring for a fixed time.

  In the first embodiment, the extension band is described as transmitting only the transmission data Du. However, in order to measure the propagation environment of each frequency band, a pilot channel or a pilot signal may be transmitted in addition to the transmission data Du. Good.

  In the above description, transmission from the base station to the terminal has been described, but conversely, transmission from the terminal to the base station can be similarly applied.

  As already mentioned, generally the transmission characteristics of the control channel must be better in its transmission quality than the transmission characteristics of the data channel. Therefore, although the main band including the control channel needs to select a frequency band with a good propagation environment, the frequency band in the best propagation environment can be selected as the main band by the above-described operation. Further, even if the propagation environment fluctuates with the passage of time, the frequency band that is always in the best propagation environment can be selected as the main band.

  Thereby, not only the transmission error of the control channel information is reduced, but the device setting on the receiving side is facilitated, and the transmission quality can be improved. Furthermore, since the number of data retransmissions due to transmission errors can be reduced, the transmission rate can be further increased.

Furthermore, since the setting of the main band is variable, it is possible to avoid an imbalance in the usage situation (load) between the frequency bands, and to improve the frequency utilization efficiency.
[Embodiment 3: Dynamic change of extension band]
First, some characteristics disclosed in the third embodiment are listed as follows.

i) making a frequency band set as an extension band among a plurality of frequency bands (band 1 to band 4) variable with time,
ii) Determining whether the propagation environment between the communication devices (10, 20) is good or not, selecting a frequency band that conforms to the frequency band of the best propagation environment among the plurality of frequency bands and setting it as an extension band. .

  iii) Further, at the time of establishing the radio line, the frequency band that can be used by the communication device (10, 20) is limited, and the main band and the extension band are dynamically allocated within the limited frequency band.

iv) Furthermore, it is to notify the counterpart communication device in advance of the setting information of the frequency band that should be set as the extension band, and execute the extension.
v) receiving frequency band setting information related to an expandable or changeable frequency band from the counterpart communication device, and changing the extension band or the main band;
vi) In addition, it also receives change timing information regarding the change timing.

vii) In addition, the determination result of the quality of the propagation environment is transmitted to the counterpart communication device through a control channel in a specific frequency band,
viii) using the detection result of the transmission quality (CQI) returned in response to the transmitted pilot channel or pilot signal between the communication devices (10, 20) to determine whether the propagation environment is good or bad;
ix) setting of the extension band based on at least one of the usable frequency of the communication device, the quality of the propagation environment in each frequency band, the usage status of each frequency band and the required transmission rate of data information (Du), or Is to determine the need for change,
x) When a new setting of the extension band is made, a change in the frequency band is notified to the counterpart communication device in advance.

FIG. 19 is a flowchart showing a first example of introduction and change of an extension band,
FIG. 20 is a flowchart showing a second example of introduction and change of an extension band,
FIG. 21 is a flowchart showing a third example of introduction and change of an extension band.

  Specifically, FIG. 19 shows a control flow in the case of selecting an extension band using the usable frequency band of the terminal and the CQI of each frequency band. FIG. 20 shows a control flow in the case of selecting an extension band using the usable frequency band, the usage state of each frequency band and the required transmission rate of transmission data. Further, FIG. 21 shows a control flow when an extension band is selected using the usable frequency band of the terminal, the CQI of each frequency band, the usage status of each frequency band, and the required transmission rate of transmission data.

In FIG.
Step S21: The usable frequency band is transmitted.

Step S22: receiving the usable frequency band,
Step S23: A pilot channel signal is transmitted in the usable frequency band.

Step S24: All pilot channel signals are received, and each SNR and the like are calculated and converted into CQI.
Step S25: Each CQI is transmitted through an uplink control channel.

Step S26: Receiving each of the above CQIs,
Step S27: Select the presence / absence of necessity of extension from the CQI, select the extension frequency band and determine the change timing,
Step S28: The extended frequency band and the change timing are transmitted on the downlink control channel.

Step S29: receiving the above extended frequency band and change timing,
Step S30: Change the setting of each circuit unit in accordance with the change timing,
Step S31: The reception operation is started in the extension band after the change.

Next, in FIG.
Step S41: The usable frequency band is transmitted.

Step S42: receiving the usable frequency band,
Step S43: Check the usage status of each frequency band and the required transmission speed of the transmission data Du,
Step S44: Select presence / absence of extension, select an extension frequency band and determine the change timing,
Step S45: The extended frequency band and the change timing are transmitted on the downlink control channel.

Step S46: receiving the extended frequency band and the change timing,
Step S47: Change the setting of each circuit unit in accordance with the change timing,
Step S48: The reception operation is started in the extended band after the change.

Furthermore, in FIG.
Step S51: Transmit each usable frequency band.

Step S52: receiving the usable frequency band,
Step S53: A pilot channel signal is transmitted in the usable frequency band.

Step S54: After receiving all the pilot channel signals, calculate each SNR etc. and convert it to CQI,
Step S55: Each CQI is transmitted through an uplink control channel.

Step S56: Each CQI is received,
Step S57: Check the usage status of each frequency band and the required transmission speed of the transmission data Du,
Step S58: Select presence / absence of necessity of extension, select an extension frequency band and determine its change timing,
Step S59: The extension frequency band and the change timing are transmitted on the downlink control channel.

Step S60: receiving the extended frequency band and the change timing,
Step S61: Change the setting of each circuit unit in accordance with the change timing,
Step S62: The reception operation is started in the extended band after the change.

  In the third embodiment, dynamic change of the extension band is described. In general, when a line is set (when a radio line is established), a frequency band that can be used by the terminal is transmitted from the terminal to the base station (or base station controller). This is the terminal usable frequency band described above. In addition, although it demonstrates supposing the case where this usable frequency band is notified, when the frequency band which can be used as a communication system is decided beforehand, it is also considered not to notify.

  As in the case of the second embodiment, the base station transmits the pilot signal Sp, and the terminal transmits the CQI calculated based on the received pilot signal Sp to the base station. Next, the base station considers the usable frequency band of the terminal, the CQI of each frequency band transmitted from the terminal, the usage status of other terminals, the required transmission rate of data Du to be transmitted, and the like. On the other hand, it is determined whether it is necessary to expand the frequency band (change the number of used frequency bands).

  When expanding, select the frequency band. Further, the above change timing for extending the use frequency band is selected. Then, the extension band selection information and the change timing are transmitted on the control channel. The terminal that has received this control channel signal changes the setting of each circuit unit in the terminal based on the information about the extension band and the change timing, and then starts reception in the extension band.

  A supplementary explanation will be given for this operation. However, the control flow in FIG. 21 described above is referred to. First, a terminal transmits a frequency band that can be used by the terminal to the base station or a base station control apparatus or the like above the base station. Receiving this, the base station transmits a pilot channel signal or pilot signal Sp in a usable frequency band. In addition, when transmitting a pilot channel signal on a common channel common to terminals, it is not necessary to select a use frequency band.

  The terminal that has received the pilot channel signal through each frequency band calculates the above-mentioned CQI based on the above-mentioned CIR, SNR, etc., and transmits this CQI calculated value to the base station through the uplink control channel. Upon receiving this, the base station considers the QoS such as the CQI, the usage status of each frequency band, and the required transmission rate of the transmission data Du, and selects whether or not the expansion is necessary and the frequency band to be used for the expansion. The band change timing and the like are determined and notified to the terminal through the downlink control channel.

  The terminal that has received the information sets or resets each circuit unit of the terminal in accordance with the change timing, and performs reception in the extended band after the change after the change timing.

  FIG. 22 is a diagram showing an example of dynamically changing the extension band in the third embodiment in an easily understandable manner. The passage of time goes from the top to the bottom of the figure. With the passage of time, the extension band selects a good frequency band in accordance with the best frequency band of the propagation environment, and every time expansion is necessary, “Band 2” → “Band 2+ Band” illustrated in the figure It will be set as “3 + band 4”. As in the latter case, the extension band can be set by combining a plurality of bands.

In this way, a frequency band having a relatively good propagation environment can be selected as an extension band even for a propagation environment that varies with time. As a result, transmission errors in the control channel information are reduced, device settings on the receiving side are facilitated, and transmission quality can be improved. Furthermore, since the number of data retransmissions can be reduced, the transmission rate can be improved. In addition, in consideration of the processing time for correcting the setting on the receiving side, the change of the setting for the apparatus is facilitated by notifying the other party in advance of the change of the extension band.
[Embodiment 4: Dynamic change of main band and extension band]
First, features disclosed in the fourth embodiment will be described below.

i) A frequency band that should be occupied by a main band among a plurality of frequency bands (bands 1 to 4) and a frequency band that should be occupied by an extension band among the plurality of frequency bands without overlapping each other, To be variable over time,
ii) To change one main band and at least one extension band at the same time.

  FIG. 23 is a flowchart showing an example of changing both the main band and the extension band.

In this figure,
Step S71: The usable frequency band is transmitted.

Step S72: receiving the usable frequency band,
Step S73: A pilot channel signal is transmitted using the usable frequency band.

Step S74: Receive all pilot channel signals, calculate each SNR etc. and change to CQI,
Step S75: Each of the above CQIs is transmitted on the uplink control channel.

Step S76: Receiving each of the above CQIs,
Step S77: Select a main band, that is, a frequency band with the best propagation environment,
Step S78: Further, select an extension band, that is, a frequency band having the second best propagation environment,
Step S79: Transmitting the above extended frequency band and its change timing through a downlink control channel,
Step S80: The change timing is selected.

Step S81: receiving the above extended frequency band and the change timing,
Step S82: Change the setting of each circuit unit according to the change timing,
Step S83: The reception operation is started in the extended band after the change.

  To supplement the description of the control flow in FIG. 23, here, one main band and one extension band are selected from the required transmission rate of the transmission data Du (see FIG. 24). Based on the CQI in each frequency band transmitted from the terminal, the frequency band with the best propagation environment is selected as the main band. Then (second) a frequency band with a good propagation environment is selected as the extension band. Subsequently, change timings are selected, and these are transmitted to the other party via the control channel.

  The terminal that has received the used frequency band information (both main band and extension band) and the change timing information changes the settings of the receiving side circuit unit in accordance with the change timing, and then changes both the main band and the extension band. Receive a signal.

  FIG. 24 is a flowchart showing an example of dynamic change of both the main band and the extension band in the fourth embodiment. Time progresses from the top to the bottom of the figure. As illustrated in this figure, as the main band is set as “Band 1” → “Band 1” → “Band 3” → “Band 2”, the extension band is set to the left and right of the main band. It is set in pairs on either the left or right side of the figure. However, both bands do not always have to be paired. For example, if attention is paid to the third row in the figure, this extended band (band 4) may not exist. The band may exist not in the illustrated band 3 but in the band 4 on the right side of the band.

  As described above, the frequency bands that are the best and the next best propagation environment can be set to the main band and the extension band, respectively. Further, even if the propagation environment fluctuates over time, the frequency band of the best and next best propagation environment can be selected as the main band and the extension band, respectively.

As a result, as in the above-described embodiment, transmission errors of control channel information are reduced, device settings on the receiving side are facilitated, and transmission quality can be improved. Furthermore, since the number of times of data retransmission can be reduced, the transmission rate can be improved. In addition, it is easy to change the device setting by notifying the other party in advance of the change of the main band and the extension band in consideration of the processing time for correcting the setting on the receiving side.
[Embodiment 5: Select main band and extension band according to propagation environment]
First, features disclosed in the fifth embodiment will be described below.

i) The quality of the propagation environment between the communication devices (10, 20) is individually determined for each of a plurality of frequency bands (band 1 to band 4), and the determination result is individually communicated for each frequency band. Is to transmit to the device,
ii) Or the quality of the propagation environment between the communication devices (10, 20) is individually determined for each of a plurality of frequency bands (band 1 to band 4), and the respective determination results for all frequency bands are multiplexed. Is transmitted to the other party's communication device.
iii) The determination result is transmitted to the counterpart communication device using any one of the main band, the extension band, and a relatively good frequency band of the propagation environment.

  In order to implement the fifth embodiment, the configuration example of FIG. 15 described above can be used, or the configuration example of FIG. 25 can be used.

  FIG. 25 is a diagram showing a device configuration example on the return side of response (CQI) information to a pilot signal. The configuration example of this figure is approximate to the configuration example of FIG. 15 described above, and the difference is that in the lower half of FIG. 15 is an individual process corresponding to each of a plurality of frequency bands, In the lower half of FIG. 25, each CQI for a plurality of frequency bands is multiplexed and processed together. That is, in FIG. 25, transmission quality (CQI) is transmitted to the other party using one control channel, and for this purpose, a multiplexing unit (Mux) 80 is introduced on the output side of the return path 72.

  In each of the above-described embodiments, when transmitting the CQI of each frequency band from the terminal to the base station, the CQI may be transmitted on the uplink control channel for each frequency band, and for example, the uplink control channel in the main band The CQIs for all frequency bands may be transmitted at.

  When transmitting CQI using an uplink control channel for each frequency band, the configuration example of FIG. 15 is used. In this configuration example, the uplink transmission data Du is not described, but the data Du can be multiplexed and transmitted on the control channel. In addition, this configuration example assumes a case where pilot channel signals are received simultaneously for a plurality of frequency bands.

  The terminal shown in FIG. 15 receives a signal in each frequency band and performs frequency conversion in accordance with each frequency band. After that, the GI removing unit 54 removes the GI, and after performing frequency-time conversion by the S / P unit 55, the FFT unit 56, and the P / S unit 57, the demodulating unit 23 demodulates. After measuring the propagation state by SNR, CIR, etc. using this signal, the CQI value is calculated.

  The CQI value calculated for each frequency band is transmitted through the control channel of each frequency band. At this time, other control channel signals can be transmitted together. Furthermore, it can be transmitted together with the uplink transmission data.

  The calculated CQI enters the lower half portion of FIG. 15 in the return path 77, is encoded by the encoding unit 78, is modulated by the modulation unit 112, and is then subjected to the S / P unit 137, IFFT The unit 138 and the P / S unit 139 perform time-frequency conversion. Further, the GI insertion unit 140 inserts a GI, converts the GI into a corresponding frequency band, and transmits it from the antenna AT.

  As described above, the CQI (propagation state) of each frequency band can be transmitted to the base station as in the above-described embodiment. Further, based on the CQI (propagation status) sent from the terminal, it is possible to select a frequency band with a good propagation environment as the main band. Similarly, a frequency band having a relatively good propagation environment can be selected as the extension band. As described above, by selecting a better frequency band, the transmission characteristics are improved and the number of data retransmissions is reduced, so that the transmission rate can be improved.

  Next, in the case of transmitting all CQIs using the uplink control channel of a specific frequency band, the configuration example of FIG. 25 is adopted. Similar to the case of using the uplink control channel for each frequency band described above, the CQI in each frequency band is calculated. These calculation results are combined into one by the multiplexing unit (Mux) 80 and then encoded by the encoding unit 78. Further, after modulation by modulation section 112, time / frequency conversion is performed by S / P section 137, IFFT section 138 and P / S section 139, and GI insertion section 140 inserts GI. Thereafter, the frequency is converted by the circuits 141 and 142 and transmitted from the antenna AT.

  The frequency band used for transmitting the CQI to be used may be the main band selected as having a relatively good transmission environment, or the frequency band having the best propagation environment (the best CQI) may be selected. Alternatively, other frequency bands may be selected. Moreover, you may use the frequency band preset as a communication system.

As described above, the CQI (propagation state) of each frequency band can be transmitted to the base station as in the above-described embodiment. Further, based on the CQI (propagation status) sent from the terminal, it is possible to select a frequency band with a good propagation environment as the main band. Similarly, it is possible to select a frequency band with a good propagation environment as the extension band. Thus, by selecting a better frequency band, the transmission characteristics are improved and the number of data retransmissions is reduced, so that the transmission rate can be improved.
[Embodiment 6: Highly efficient transmission of used frequency band information]
The feature disclosed in the sixth embodiment is that, for each of a plurality of frequency bands (band 1 to band 4), (i) a frequency band identification number, (ii) used / unused as a main band, (iii) an extended band Used / unused and (iv) while maintaining the current status, at least one of the information (i to iv) is encoded and transmitted to the counterpart communication device.

  FIG. 26 is a diagram illustrating a table for explaining high-efficiency transmission of used frequency band information. Table 1 shows an example of correspondence between used frequency band and band number, and Tables 2 and 3 show a first example and a second example, respectively, regarding how to set the used frequency band and used / unused.

  In the transmission of the used frequency band information in each of the above-described embodiments, for example, by assigning a number to the frequency band and transmitting the number, the amount of control channel information is reduced as compared with the case of transmitting the frequency value itself. be able to. Specific examples will be described using Tables 1 to 3 above. Here, an example in which the frequency band that can be used in the entire communication system is 800 [MHz] to 820 [MHz] and is divided into four frequency bands as shown in FIG.

  First, a band number (1, 2, 3, 4) is assigned to each band as shown in Table 1. Further, as shown in Table 2, which frequency band is used as the main band and which frequency band is used as the extension band (or is not used).

At this time, for example, when band 1 is “unused”, band 2 is used as “main band”, band 3 is used as “extended band”, and band 4 is “unused”, the following control data “ yy1100zz ”where yy and zz are“ 01 ”or“ 10 ”
It becomes.

  Here, the control data is created in the order of band 1, band 2, band 3, and band 4. However, this order may be any order as long as it can be recognized by the transmitting side and the receiving side. . In addition, the number of bands can be arbitrarily increased or decreased. Furthermore, although four continuous frequency bands have been described here as an example, a discontinuous frequency band having an unused band in the middle may be used.

  As described above, by encoding (table-izing), for example, the amount of information can be reduced as compared with the case of transmitting the value of the center frequency of the band itself.

  Further, as shown in Table 3, a setting may be provided in the case where there is no change in the usage status, that is, in the case of “maintain current status”.

As described above, the data length of the control signal can be compressed by encoding (tableting) the used frequency band information. Therefore, the ratio between the transmission data and the control channel information is reduced for the latter, thereby improving the transmission efficiency of the transmission data.
[Embodiment 7: Continuous setting and discontinuous setting of extension band]
First, the characteristics disclosed in the seventh embodiment are listed as follows.

i) allocating one extension band or two or more consecutive extension bands to a frequency band continuous to the main band on the frequency axis;
ii) or further including an isolated extension band that is not continuous with any of the extension bands on the frequency axis,
iii) For the part of the unused frequency band associated with the isolated extended band, a meaningless signal is inserted and transmitted to the counterpart communication device. In addition, as a figure which represents this Embodiment 7 suitably, there exist FIG. 27 and above-mentioned FIG.

  FIG. 27 is a diagram showing an example of dynamically changing the extension band. FIG. 22 shows a case where continuous extension bands are selected, whereas FIG. The case where the column reference is performed is shown. 27 is exactly the same as the view of FIG. This will be specifically described below.

  First, the case where the extension band is continuous will be described. FIG. 22 described above also shows that the extension band is continuously selected. However, as an example, a case is shown in which a continuous band paired with the main band is selected as the extension band. In the mode of FIG. 22, since the extension band is continuous with the main band, signal processing is simplified compared to the case of discontinuity (FIG. 27). The transmission operation and the reception operation are the same as those described in the above embodiments.

  On the other hand, FIG. 27 also shows the case where the extension band is discontinuous as described above (fourth stage). As described above, the extension band can be selected discontinuously with respect to the main band or the adjacent extension band in consideration of the usable frequency band of the terminal, the propagation environment, and the balance with other terminals.

  In the description so far, subcarriers straddling continuous frequency bands (see the dotted SC in FIG. 22) have not been set, but depending on the usage status of other terminals, subcarriers straddling two frequency bands It is also possible to increase the amount of transmission information accordingly.

  In addition, the receiving side terminal does not receive the signal in the discontinuous frequency band, or forcibly processes the signal as a meaningless signal. Thereby, even if the extension band is discontinuous, reception can be performed without any trouble.

As described above, by setting a discontinuous extension band, the extension band can be flexibly selected in consideration of the usable frequency band of the terminal, the propagation environment, and the use status of other terminals. This further improves the frequency utilization efficiency.
[Embodiment 8: The number of subcarriers in each frequency band is constant]
A feature disclosed in the eighth embodiment is that each of a plurality of frequency bands (band 1 to band 4) has a predetermined constant value, and the number of a series of subcarriers in each band is also a predetermined constant. Value.

FIG. 28 is a diagram showing a first example of a bandwidth extension pattern,
FIG. 29 is a diagram showing a second example of the bandwidth extension pattern.
FIG. 30 is a diagram illustrating a third example of the bandwidth extension pattern.

  Note that the way of viewing FIGS. 28 to 30 is almost the same as the way of viewing FIG. 22, FIG. 24, FIG. 27, etc., and FIG. 22, FIG. 24, FIG. On the other hand, in FIGS. 28-30, it replaces with such an actual waveform and is only represented as a block of a subcarrier. This is to facilitate explanation of the eighth embodiment. In other words, it expresses the concept of “frequency band unit” visually in an easily understandable manner. The terms described in FIGS. 28 to 30 have already been explained except for “processing delay”. For example, referring to FIG. 4, the processing delay is that the use frequency band information If is input to the use frequency band setting unit 25, the band setting instruction signal Sb is generated, and the parameter setting in each circuit unit is completed. This means the time delay required for processing until

  In general, when a bandwidth is changed in a communication method using a series of subcarriers such as a multicarrier transmission method (OFDM, MC-CDMA, etc.), the change is usually performed in units of subcarriers. In this case, use / unuse must be set for each subcarrier. Further, in both the transmission process and the reception process, signal processing in consideration of use / unuse is required in units of subcarriers, and the band setting may be complicated and complicated. Furthermore, when performing user multiplexing, it is necessary to control the use / unuse of each subcarrier between users, resulting in a decrease in frequency utilization efficiency.

  Therefore, in the eighth embodiment, the usable frequency band of the entire communication system is divided into a plurality of bands (band 1 to band 4), and “the number of subcarriers is constant” in each of the divided frequency bands. Thus, transmission between communication apparatuses is performed using one or a plurality of frequency bands. Thereby, the frequency utilization efficiency can be improved.

  Specifically, for example, one frequency band is set to 5 [MHz], and the number of subcarriers in the frequency band is set to 25. A plurality of such frequency bands are set, and the use frequency band is made variable in frequency band units. 28 to 30 show specific examples of band expansion in band units. In each figure, the horizontal axis indicates the bandwidth, and one hatched block represents one frequency band, and a plurality of subcarriers are included in one frequency band. Similar to FIG. 9, it can be considered that band 1, band 2, band 3, and band 4 are from the left.

  FIG. 28 shows a case where band 1 is the main band, and FIG. 29 shows a case where band 2 is the main band. FIG. 30 shows an example in which the setting of the extension band is changed with time, and the extension band includes a discontinuous one (see the sixth row). The specific operation of transmission / reception is as described in the above embodiment.

As described above, the used frequency band can be easily changed, and the frequency utilization efficiency can be increased. Furthermore, the transmission / reception operation described above is further simplified and the configuration of the transmitter / receiver is simplified as compared with the case where the use frequency band is variable in units of subcarriers.
[Embodiment 9: The number of subcarriers and the subcarrier bandwidth in each frequency band are both constant]
The features disclosed in the ninth embodiment are as follows.

i) Each of a plurality of frequency bands (band 1 to band 4) has a predetermined constant value, and the bandwidth of each subcarrier in each band is also a predetermined constant value.
ii) Furthermore, the number of subcarriers is also set to a predetermined constant value. Thereby, the main band and the extension band can be easily set in frequency band units.

  In Embodiment 8 described above, the number of subcarriers per band is constant, but in Embodiment 9, the bandwidth of each subcarrier is also constant.

As a result, the difference between the bands is only the value of each center frequency. Thereby, the baseband signal processing is made uniform regardless of the frequency band, and the configuration of the transceiver is further simplified as compared with the eighth embodiment.
[Embodiment 10: Band setting based on difference between required transmission rate and actual transmission rate]
The characteristics disclosed in the tenth embodiment are listed as follows.

i) In order to determine the necessity / unnecessity of the extension band, a difference (S1-S2) between the required transmission rate S1 assumed to be necessary for information exchange and the actual transmission rate S2 actually achieved is calculated. According to whether the difference is positive or negative, it is determined that the extension band is necessary and unnecessary,
ii) Here, the actual transmission rate is obtained from the number of transmission data information calculated from the number of frequency bands to be used and the transmission interval of the transmission data information.

FIG. 31 is a diagram illustrating a configuration example of a communication device (transmission side) according to Embodiment 10;
FIG. 32 is a flowchart showing an operation example in the apparatus of FIG.

  Referring first to FIG. 31, this figure is almost the same as the configuration of FIG. 5 (same as in FIG. 3), but the frequency band selection / setting unit 85 (deformation of 15) and actual transmission shown at the left end of this figure. The difference is that the speed calculation unit 86 is introduced.

Referring to FIG. 32, the operation is as follows.
Step S91: Check the required transmission rate,
Step S92: Confirm the transmission data amount,
Step S93: The actual transmission rate is calculated.

  Step S94: Based on the speed values in steps S91 and S93, it is determined whether or not the use frequency band needs to be extended, and it is assumed that this is necessary.

Step S95: Select an extended frequency band, determine a change timing,
Step S96: The extension frequency band and the change timing are transmitted on the downlink control channel.

Step S97: receiving the extension frequency band and the change timing,
Step S98: Change the setting of each circuit unit in accordance with the change timing,
Step S99: Reception is started in the changed extension band.

  More specifically, in Embodiment 1 described above, the use / unuse of the extension band and the number of extension bands are determined based only on the required transmission rate. In Embodiment 8, however, the actual actual transmission rate is determined. The bandwidth is expanded or reduced in consideration of the difference from the required transmission rate.

  A specific example will be described with reference to FIGS. 31 and 32 again. In addition, description is abbreviate | omitted about the same part as Embodiment 1. FIG.

  It is assumed that a required transmission rate Rd of certain transmission data Du is 10 [Mbps], and transmission is performed using the main band and the extension band. At this time, the actual actual transmission rate Ra can be calculated by the actual transmission rate calculation unit 86 in FIG. 31 from the number of transmission data calculated from the number of used frequency bands and the transmission interval. The actual transmission rate Ra and the required transmission rate Rd are compared in the selection / setting unit 85, and when the actual transmission rate Ra is lower, the use frequency band is increased (extended). For example, when it is determined that the actual transmission rate Ra is significantly higher than the required transmission rate Rd and the required transmission rate Rd can be observed even if the usage frequency band is reduced, the usage frequency band is reduced (reduced).

As described above, it is possible to improve the frequency utilization efficiency while satisfying the required transmission rate. In addition to the above method, whether the data transmitted from the base station has been transmitted to the terminal (ACK / NACK) is returned to the base station, the actual transmission rate is calculated based on this, and the used frequency band May be made variable. In addition, the terminal may calculate the transmission rate based on the amount of data transmitted from the base station, send it back to the base station, and vary the use frequency band based on the value.
[Embodiment 11: Expansion of use frequency band]
FIG. 33 is a diagram for explaining the eleventh embodiment, and particularly notable portions are “the band being restricted” and “the entire frequency band after the restriction is released”. The features disclosed in the present embodiment 11 are as described below.

i) In a communication system for exchanging information between communication devices (10, 20) in a multi-carrier transmission scheme using a series of subcarriers, all frequency bands to be allocated to this communication system in the future ("Release restriction" in FIG. 33) Among a plurality of divided frequency bands (band a to band d) obtained by dividing the entire frequency band later), currently only a part of the divided frequency bands ("band a") is permitted to be used. (Refer to “band in restriction”), the divided frequency band “band a” that is permitted to be used is further divided into one or more frequency bands (bands 1 to 4 in the embodiments 1 to 10). The other divided frequency bands (band b, band c, and band d) that are currently limited are similarly divided into one or a plurality of frequency bands. (As in bands 1 to 4 in the embodiments 1 to 10). When the restriction is lifted in the future, the current use is permitted for each of a plurality of divided frequency bands (bands b to d) that are not currently used by dividing the entire frequency band. And immediately applying the same operation as dividing the divided frequency band (band a) into one or a plurality of frequency bands,
ii) A plurality of divided frequency bands (bands a to d) obtained by dividing the entire frequency band here have a constant bandwidth with each other, and subcarriers in each of the divided frequency bands The number and bandwidth are mutually constant values.

  More specifically, the frequency band that can be used by this communication system (or base station) is limited due to the balance with other communication systems, and then the frequency used by the other communication system is shifted to another. There may be cases where the restriction is lifted for some reason.

  When such a case is assumed, the restricted use frequency band ("restricted band a") is divided into one or a plurality of frequency bands as in the above-described embodiment. At this time, the restricted frequency bands (band b, band c, band d) are also divided into one or a plurality of frequency bands. It should be noted that the usable frequency band (band a) and the restricted frequency bands (bands b to d) are preferably divided by the same bandwidth. It is assumed that FIG. 33 is divided with the same bandwidth in this way. In FIG. 33, the frequency band to be used is limited to the band a and is operated as one frequency band, and the restricted frequency band is divided into three bands (band b to band d). Bands b to d are not currently available due to limitations. Note that the number of subcarriers and the subcarrier bandwidth in these bands are preferably constant.

  During the restriction, the frequency band used is one (band a), so that the usable frequency band cannot be expanded. According to the eleventh embodiment, after the restriction is released, the frequency band to be used becomes four (bands a to d), and it is possible to immediately shift to the operation of the above-described embodiment.

  By setting the frequency band as described above, the use frequency band is currently limited. However, when the restriction is released after that, the system operation according to the present invention can be performed immediately. This allows flexible operation of the communication system.

  As described above in detail, according to the present invention, it is possible to easily change the used frequency bandwidth, and it is possible to greatly improve the frequency utilization efficiency.

Claims (2)

Each of the communication devices accommodated in a communication system that performs communication using a plurality of bands each applying a time division multiple access method,
Using the main band set in advance from among a plurality of frequency bands assigned to the communication system, receiving the used frequency band information and data information defining which of the remaining frequency bands should be used,
The main band is set when a wireless line is established with a communication apparatus on the other side. In a communication system that exchanges information between communication devices using a plurality of bands each applying a time division multiple access method,
One communication device is
A main band is set in advance from among a plurality of frequency bands assigned to the communication system, and using the main band, the remaining frequency band to be used is transmitted and used frequency band information is transmitted. In addition, it transmits data information,
Other communication devices
Using the main band, receiving the used frequency band information and data information,
The main band is set when a radio line is established between the communication devices.

Images