JP2005318419A - Radio transmission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize substantially speed-up of transmission of information data by selecting a transmission system in accordance with information data to be transmitted in a transmission frame. <P>SOLUTION: The radio transmission apparatus is provided with a plurality of transmitting antennas (27a, 27b), selects one transmission system from among a plurality of transmission systems, and radio transmits the information according to the selected transmission system. The apparatus is provided with: a first transmission part 24 for transmitting information by performing space division multiplex by using the plurality of antennas (27a, 27b); a second transmission part 25 for transmitting the information without performing the space division multiplex by using the plurality of antennas or a single antenna (27a, 27b); a calculating part 21 for calculating a length of the transmission frame every transmission system; and a transmission system selecting part 22 for selecting a transmission system where the calculated length of the transmission frame is the shortest. Either the first transmission part or the second transmission part radio transmits the information according to the selected transmission system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless transmission device that selects any one transmission method from a plurality of transmission methods and wirelessly transmits information using the selected transmission method.

  In the field of mobile communication, how to construct a high-quality and large-capacity wireless communication system with a limited frequency is a major issue. As a technique for solving such a problem, the application of a space division multiplexing method for improving the frequency use efficiency by spatially multiplexing transmission data at the same frequency using a plurality of antennas on the transmitting side and the receiving side has been studied. Yes. In this space division multiplexing method, the modulation method is the same as the conventional method, but since different information is transmitted from a plurality of transmission antennas at the same frequency and multiplexed in space, for example, when two antennas are used, the frequency used The transmission capacity can be doubled without increasing the bandwidth. As a system using this space division multiplexing, there is a system called “Multi-Input Multi-Output (hereinafter referred to as“ MIMO ”) system”.

  As a related prior art document, for example, Japanese Patent Application Laid-Open No. 2003-204317 discloses a “radio transmission apparatus and radio communication method” for improving the frequency utilization efficiency and the transmission speed while maintaining communication quality. JP-A-2003-318853 discloses an “OFDM signal transmission apparatus, OFDM signal transmission for improving transmission quality while maintaining transmission capacity in OFDM signal transmission for switching between spatial multiplexing transmission and spatial diversity transmission. Apparatus and OFDM signal receiving apparatus "are disclosed. In addition, "2003 Throughput Maximized Transmission Control Method in MIMO System" is disclosed in "2003 IEICE Communication Society Conference, B-5-12". Japanese Patent Laid-Open No. 2003-283441 discloses a “signal transmission system, transmission device, and reception device” for accurately detecting a transmission path state between a transmission device and a reception device. “Communication Society RCS 2003-21” discloses “Timing / Frequency Synchronization Method in MIMO-OFDM System”.

  In the above prior art, a method of acquiring the propagation path status, controlling the transmission frequency of each of the plurality of antennas and the number of pieces of information transmitted from the plurality of antennas according to the acquired propagation path status, and the same frequency. Communication quality by switching and controlling the spatial diversity that transmits the same signal at the same frequency as the spatial multiplexing system that transmits different signals, and the selection and combination of transmission antennas, modulation method, and coding rate A technique for improving frequency utilization efficiency and transmission speed while maintaining the above is employed.

  More specifically, when the acquired propagation path condition is good, data transmission is performed using the space division multiplexing method. On the other hand, when the propagation path condition is poor, for example, the spatial multiplexing method such as space diversity is used. Send data without using. Further, the modulation scheme and the coding rate are controlled by combining and selecting a plurality of transmission antennas according to the acquired propagation path conditions. By adopting these methods, a situation in which a transmission signal cannot be separated and detected from a spatially multiplexed signal on the receiving side is avoided.

  FIG. 10 is a diagram illustrating a schematic configuration of a conventional wireless communication apparatus. The conventional wireless communication device 120 includes a wireless transmission device 121 and a wireless reception device 122. In the wireless transmission device 121, the transmission control unit 123 controls the entire wireless transmission device 121. The transmission control unit 123 performs operations of the space division multiplex transmission processing unit 125 and the non-space division multiplex transmission processing unit 126 according to the reception quality measured by the reception quality measurement unit 124 in the wireless reception device 122, and the data selection switch 127. A control signal for controlling switching of .about.129 is output.

  Here, for example, a case where the reception quality measuring unit 124 measures the error rate of the received data as the reception quality will be described. When the error rate measured by the reception quality measuring unit 124 is higher than a preset threshold value, the transmission control unit 123 sends a signal input from the transmission control unit 123 to the data selection switch 127 using non-space division multiplexing. A control signal for switching the data selection switch 127 to be output to the transmission processing unit 126 is output. In addition, the transmission control unit 123 outputs a control signal that causes the non-space division multiplex transmission processing unit 126 to output the signal input from the data selection switch 127 by performing non-space division multiplex transmission processing. In addition, the transmission control unit 123 outputs a control signal for causing the data selection switch 128 and the data selection switch 129 to output a signal input from the non-space division multiplex transmission processing unit 126 to at least one of the frequency conversion units 130 and 131. Output.

  On the other hand, when the error rate measured by the reception quality measuring unit 124 is lower than a preset threshold value, the transmission control unit 123 performs spatial division on the signal input from the transmission control unit 123 to the data selection switch 127. A control signal for switching the data selection switch 127 to be output to the multiplex transmission processing unit 125 is output. Also, the transmission control unit 123 outputs a control signal that causes the space division multiplex transmission processing unit 125 to output the signal input from the data selection switch 127 by performing space division multiplex transmission processing. Also, the transmission control unit 123 outputs a control signal that causes the frequency conversion units 130 and 131 to output the signal input from the space division multiplex transmission processing unit 125 to the data selection switch 128 and the data selection switch 129.

  The frequency converters 130 and 131 up-convert the input signal to a radio frequency and output it. The up-converted transmission signal is transmitted via at least one of the transmission antennas 132 and 133. In addition, said non-space division multiplex transmission process means the normal transmission process which does not perform space diversity processing or space diversity processing.

  On the other hand, in radio reception apparatus 122, the received signal received by at least one of reception antennas 135 and 136 is down-converted by at least one of frequency conversion units 137 and 138. The reception control unit 139 controls the entire radio reception apparatus 122 and outputs a control signal for switching the data selection switches 140 and 141, and receives the received data from the space division multiplex reception processing unit 143 or the non-space division multiplex reception processing unit 144. Output to either one. Also, the reception control unit 139 outputs a control signal for switching the data selection switch 142, and the reception control unit 139 outputs a signal output from either the space division multiplex reception processing unit 143 or the non-space division multiplex reception processing unit 144. Output. The reception quality measuring unit 124 measures the error rate of received data as reception quality under the control of the reception control unit 139.

As described above, the conventional wireless communication apparatus performs non-spatial division multiplex transmission and non-spatial division multiplex reception when the propagation environment is poor and the reception quality is poor, that is, when the error rate is high. When the error rate is good, that is, when the error rate is low, space division multiplex transmission and space division multiplex reception are performed to increase the transmission capacity while maintaining communication quality. That is, the transmission method is adaptively switched according to the propagation state, thereby increasing the transmission data capacity while maintaining the communication quality.
JP 2003-204317 A JP 2003-318853 A Japanese Patent Laid-Open No. 2003-060604 JP 2003-283441 A Sudo, Hara and Otsuki, "Maximum Throughput Transmission Control Method for MIMO Systems", 2003 IEICE Communication Society Conference, B-5-12 IEICE RCS2003-21 “Timing / Frequency Synchronization Method in MIMO-OFDM System”

  However, since only the increase in the transmission data capacity in the physical layer is considered in the above-described conventional technology, the increase in the information data capacity may not always be realized. FIG. 11 shows an example of a transmission frame configuration used for normal transmission without performing space division multiplex transmission. FIG. 12 shows an example of the configuration of a transmission frame used for space division multiplex transmission. Here, in FIG. 12, from the upper side to the lower side of the page, an example of the configuration of the transmission frame in the case of the space division multiplexing number 2, the space division multiplexing number 3, and the space division multiplexing number 4, and the schematic configuration As an example, the structure of a transmission frame in the case of the space division multiplexing number X is shown. Note that although the notation of pilot signals is unified here, it is not limited to the same signal.

  For example, in the conventionally proposed transmission frame configuration, the transmission frame is composed of a pilot signal for propagation path estimation and a data signal, and the ratio of the pilot signal in the transmission frame transmitted from one transmission antenna (hereinafter, "Overhead") increases when the space division multiplexing method is used than when the space division multiplexing method is not used, and when the amount of data signals is small, the case where the space division multiplexing method is used There may be a disadvantage that the transmission frame length becomes longer due to the overhead than when the space division multiplexing method is not used. In addition, when the transmission frame length is short, the transmission period of the data signal is short, and the data of the information data that can be transmitted in the transmission frame is shorter when the space division multiplexing method is used than when the space division multiplexing method is not used. There may be a disadvantage that the transmission amount is reduced due to overhead. Further, as the number of antennas to be used is increased and the number of transmission signals to be spatially multiplexed is increased, in other words, as the number of spatial division multiplexing is increased, the amount of pilot signals allocated to one transmission frame increases and the pilot signal section becomes longer. As a result, there is a problem that the overhead becomes large and the above-mentioned inconvenience appears remarkably.

  The present invention has been made in view of such circumstances, and by selecting a transmission method according to information data to be transmitted in a transmission frame, it is possible to substantially increase the speed of information data transmission. An object of the present invention is to provide a wireless transmission device that can be used.

  (1) In order to achieve the above object, the present invention has taken the following measures. That is, a wireless transmission device according to the present invention is a wireless transmission device that includes a plurality of transmission antennas, selects any one transmission method from a plurality of transmission methods, and wirelessly transmits information according to the selected transmission method. A first transmitter that transmits information by space-division multiplexing using a plurality of the antennas, and a second transmitter that transmits information without space-division multiplexing using a plurality of or a single antenna. A calculation unit that calculates the length of a transmission frame for each transmission method; and a transmission method selection unit that selects a transmission method with the shortest transmission frame length, and the first transmission unit. Alternatively, either one of the second transmission units wirelessly transmits information using the selected transmission method.

  In this way, the length of the transmission frame is calculated for each transmission method, the transmission method having the shortest transmission frame length is selected, and information is wirelessly transmitted using the selected transmission method, so the transmission occupation time is shortened. And transmission efficiency can be improved. For example, when the transmission frame length becomes large even in the space division multiplexing method, the space division multiplexing method is not used and the non-space division multiplexing method is used. Thereby, transmission efficiency can be improved. As a result, it is possible to perform transmission utilizing the advantages of the space division multiplexing method and the non-space division multiplexing method.

  (2) Further, the wireless transmission device according to the present invention includes a plurality of transmission antennas, selects any one transmission method from a plurality of transmission methods, and wirelessly transmits information by the selected transmission method. A first transmitter that transmits information by space-division multiplexing using a plurality of the antennas, and a second transmitter that transmits information without space-division multiplexing by using a plurality of or a single antenna. A transmission unit; a calculation unit that calculates the number of symbols included in a transmission frame for each transmission method; and a transmission method selection unit that selects a transmission method with the smallest calculated number of symbols. Any one of the transmission unit and the second transmission unit wirelessly transmits information by the selected transmission method.

  In this way, the number of symbols included in the transmission frame is calculated for each transmission method, the transmission method having the smallest number of symbols is selected, and information is wirelessly transmitted using the selected transmission method, thereby shortening the transmission occupation time. And transmission efficiency can be improved. For example, when the number of symbols included in a transmission frame increases even in the space division multiplexing method, the space division multiplexing method is not used and the non-space division multiplexing method is used. Thereby, transmission efficiency can be improved. As a result, it is possible to perform transmission utilizing the advantages of the space division multiplexing method and the non-space division multiplexing method.

  (3) Further, in the wireless transmission device according to the present invention, the calculation unit is configured to transmit the transmission frame based on information indicating a transmission data amount, information indicating a spatial division multiplexing number, modulation scheme information, and coding scheme information. The length or the number of symbols is calculated.

  With this configuration, it is possible to calculate the length of transmission frame or the number of symbols specific to each transmission method.

  (4) In addition, a wireless transmission device according to the present invention includes a plurality of transmission antennas, selects any one transmission method from a plurality of transmission methods, and wirelessly transmits information according to the selected transmission method. A first transmitter that transmits information by space-division multiplexing using a plurality of antennas, and a second transmitter that transmits information without space-division multiplexing by using a plurality of or single antennas. A transmission unit, a calculation unit for calculating a transmission amount of transmission data included in a transmission frame of a certain length for each transmission method, and a transmission method for selecting a transmission method having the largest transmission amount of the calculated transmission data A selection unit, wherein one of the first transmission unit and the second transmission unit wirelessly transmits information by the selected transmission method.

  In this way, the transmission amount of transmission data included in a transmission frame of a certain length is calculated for each transmission method, the transmission method with the largest transmission data transmission amount is selected, and information is wirelessly transmitted using the selected transmission method. Since transmission is performed, transmission efficiency can be increased, and more transmission capacity can be realized. For example, if the transmission amount of transmission data contained in a transmission frame of a certain length is reduced even in the space division multiplexing method, the space division multiplexing method is not used and the non-space division multiplexing method is used. . Thereby, transmission efficiency can be improved. As a result, it is possible to perform transmission utilizing the advantages of the space division multiplexing method and the non-space division multiplexing method.

  (5) Further, in the wireless transmission device according to the present invention, the calculating unit transmits the transmission based on information indicating a length of a transmission frame, information indicating a spatial division multiplexing number, modulation scheme information, and coding scheme information. It is characterized by calculating the data transmission amount.

  With this configuration, it is possible to calculate the transmission amount of transmission data unique to each transmission method.

  (6) Further, in the wireless transmission device according to the present invention, the calculation unit calculates the length of the transmission frame, the number of symbols, or the transmission amount of the transmission data, and the transmission method selection unit transmits the transmission. It is further characterized by further comprising a control unit that controls the frequency of selecting a method.

  Thus, since the frequency at which the calculation unit and the transmission method selection unit operate is controlled, for example, when the data transmission amount is constant to some extent over several transmission frames, there is no need to reduce the frequency. It is possible to reduce the amount of calculation and power consumption by stopping the operation. On the other hand, when increasing the frequency, for example, when the calculation unit and the transmission method selection unit are operated each time a transmission frame is transmitted, the transmission efficiency can be increased.

  (7) Further, in the wireless transmission device according to the present invention, the transmission method selection unit includes a table associating a transmission method according to a length of the transmission frame, the number of symbols, or a transmission amount of the transmission data, An extraction unit that extracts a transmission method corresponding to the length of the transmission frame calculated by the calculation unit, the number of symbols, or the transmission amount of the transmission data from the table.

  As described above, the transmission frame length, the number of symbols, or the table for associating the transmission method according to the transmission amount of transmission data is provided, and the transmission frame length, the number of symbols, or the transmission calculated by the calculation unit is provided. Since the transmission method corresponding to the data transmission amount is extracted from the table, the processing for selecting the transmission method in comparison with the case of calculating the transmission frame length, the number of symbols, or the transmission data transmission amount for each transmission frame is performed. It is possible to simplify and reduce the amount of calculation. As a result, it is possible to reduce power consumption.

  (8) In addition, the wireless transmission device according to the present invention is characterized in that either the first transmission unit or the second transmission unit wirelessly transmits information indicating the extracted transmission method. .

  As described above, since the information indicating the extracted transmission method is wirelessly transmitted, it is possible to instruct other wireless communication apparatuses to use the selected transmission method. For example, when this wireless transmission device is used as a base station or a centralized control station and a mobile station of a communication system, when the number of mobile stations existing in the control area increases, each mobile station has its own selected transmission method. The base station or the central control station notifies the base station or the central control station, and the base station or the central control station must frequently perform the transmission system switching operation for each mobile station. For this reason, the base station or the centralized control station can transmit information indicating the transmission method to instruct the mobile station to use the transmission method. In the mobile station, by transmitting information by the instructed transmission method, the uniformity regarding the control of the communication system is improved, and it becomes possible to avoid complicated processing.

  (9) Further, the mobile station according to the present invention provides the wireless transmission device according to any one of claims 1 to 8 and the information indicating the transmission scheme transmitted from the wireless transmission device according to claim 8. A wireless reception device for receiving information, wherein the wireless transmission device wirelessly transmits information using the transmission method received by the wireless reception device, using either the first transmission unit or the second transmission unit. It is characterized by transmitting.

  As described above, since the mobile station wirelessly transmits information using either the first transmission unit or the second transmission unit based on the received information indicating the transmission method, control of the communication system is performed. It is possible to improve unity and avoid complicated processing.

  (10) A radio communication system according to the present invention comprises a base station or a central control station including the radio transmission device according to claim 8 and a mobile station according to claim 9. .

  Thus, according to the radio communication system according to the present invention, the length of the transmission frame, the number of symbols, or the transmission data transmission amount is calculated for each transmission method, the most appropriate transmission method is selected, and the selected Since information is wirelessly transmitted by the transmission method, it is possible to improve transmission efficiency. In addition, it is possible to perform transmission utilizing the advantages of the space division multiplexing system and the non-space division multiplexing system.

  According to the present invention, since the most appropriate transmission method is selected and information is wirelessly transmitted using the selected transmission method, it is possible to improve transmission efficiency. In addition, it is possible to perform transmission utilizing the advantages of the space division multiplexing system and the non-space division multiplexing system.

(First embodiment)
The wireless transmission device according to the first embodiment includes a plurality of transmission antennas, calculates a transmission frame length, selects a transmission method that minimizes the transmission frame length, and wirelessly transmits information according to the selected transmission method. As a result, the transmission occupation time is shortened and the transmission efficiency is improved.

  FIG. 1 is a diagram illustrating an example in which the wireless transmission device according to the first embodiment is applied to a mobile terminal such as a car phone or a mobile phone. The wireless communication device 1 includes a transmission unit 2 as a wireless transmission device, a reception unit 3 as a wireless reception device, a transmission / reception control unit 4 that controls each unit, a duplexer 5, a plurality of antennas 6-1 to 6-n, It comprises a speaker 7, a receiver 8, a display 9 such as a liquid crystal panel, and a dial key 10 including various function keys.

  FIG. 2 is a diagram illustrating a configuration of the transmission unit 2 as a wireless transmission device. The transmission unit 2 has a function of performing space division multiplex transmission using a plurality of antennas and a function of performing non-space division multiplex transmission. In the transmission unit 2, the transmission control unit 20 performs overall control related to the transmission of the transmission unit 2 as a wireless transmission device, and transfers information data transferred from the upper layer to the lower layer. As parameters relating to transmission, a modulation scheme, a coding rate, and a data transmission amount are transferred.

  The transmission frame length calculation unit 21 transmits the transmission frame length when performing space division multiplex transmission and non-space division multiplex transmission based on the modulation scheme, coding rate, and data transmission amount input from the transmission control unit 20. Perform the calculation. The transmission frame length calculation unit 21 constitutes a calculation unit. The transmission frame is composed of pilot signals and data signals used for propagation path estimation and timing synchronization. When the modulation multi-level number is M, the coding rate is R, the transmission data amount is D, and the space division multiplexing number is N, the number of symbols of the data signal transmitted from one transmission antenna is expressed by the following equation.

上式から求められたデータ信号のシンボル数に既知であるパイロット信号のシンボル数を合わせたものが伝送フレームの全体のシンボル数になる。

The total number of symbols of the transmission frame is obtained by adding the number of symbols of the pilot signal that is known to the number of symbols of the data signal obtained from the above equation.

パイロット信号は、使用する伝送方式によって異なる。空間分割多重送信と非空間分割多重送信では異なる長さのパイロット信号が使用され、計算によって求められたデータ信号のシンボル数にそれぞれのパイロット信号をあわせて、１つの送信アンテナより送信される伝送フレームの全体のシンボル数からフレーム長を算出する。

The pilot signal differs depending on the transmission method used. A pilot signal having a different length is used for space division multiplex transmission and non-space division multiplex transmission, and each transmission signal is transmitted from one transmission antenna by combining each pilot signal with the number of symbols of the data signal obtained by calculation. The frame length is calculated from the total number of symbols.

  Based on the calculation result input from the transmission frame length calculation unit 21, the transmission method selection unit 22 selects a transmission method with the shortest transmission frame length. In accordance with the selection result, the transmission control unit 20 controls the data selection switch and the transmission processing unit. That is, if the notified transmission method is space division multiplex transmission, the transmission control unit 20 outputs a control signal for causing the data selection switch 23a to output the input signal to the space division multiplex transmission processing unit 24. . Then, a control signal is output to the space division multiplex transmission processing unit 24 so that the input signal is subjected to space division multiplex transmission processing and output. In addition, a control signal for outputting a signal input from the space division multiplex transmission processing unit 24 is output to the data selection switches 23b and 23c.

  On the other hand, if the notified transmission method is non-space division multiplex transmission, the transmission control unit 20 sends a control signal for causing the data selection switch 23a to output an input signal to the non-space division multiplex transmission processing unit 25. Output. Also, the transmission control unit 20 outputs a control signal that causes the non-space division multiplex transmission processing unit 25 to output the input signal by performing non-space division multiplex transmission processing. Further, the transmission control unit 20 outputs a control signal that causes the data selection switches 23b and 23c to output a signal input from the non-space division multiplex transmission processing unit 25.

  At least one of the frequency converters 26a and 26b up-converts the input signal to a radio frequency and outputs it. The up-converted transmission signal is transmitted via at least one of the antennas 27a and 27b.

  The receiving unit 3 as a wireless receiving device performs processing according to whether it is non-space division multiplexing or space division multiplexing according to control information related to the transmission method notified from the wireless transmission device. This can be realized by a technique such as transmitting a notification signal or a control message. That is, it can be realized by a method similar to the conventional method.

  FIG. 3 shows a configuration of a wireless transmission device (transmission unit) in the case of having three antennas. Thus, when a plurality of space division multiplexing numbers can be selected, the transmission frame length calculation unit 21 calculates the transmission frame length in each space division multiplexing number. Then, based on the calculation result input from the transmission frame length calculation unit 21, the transmission method selection unit 22 selects a transmission method with the shortest transmission frame length. In accordance with the selection result, the transmission control unit 20 controls the data selection switch and the transmission processing unit. That is, when the transmission control unit 20 extends the same operation as the above operation to three transmission antennas, and further uses three transmission antennas as space division multiplex transmission and performs transmission with the number of space division multiplexes of three. A control signal for outputting a signal input from the space division multiplex transmission processing unit 24 is output to all of the data selection switches 23b, 23c, and 23d. In the case of performing transmission with space division multiplexing number 2 using two transmission antennas as space division multiplexing transmission, the space division multiplexing transmission processing unit 24 sends any two of the data selection switches 23b, 23c, and 23d. A control signal that outputs an input signal is output, and a control signal that does not output a signal input from the space division multiplex transmission processing unit 24 is output to the remaining one.

  In addition, when performing transmission diversity transmission using three transmission antennas as non-space division multiplex transmission, the transmission control unit 20 performs non-space division multiplex transmission processing units for all of the data selection switches 23b, 23c, and 23d. A control signal for outputting a signal input from 25 is output. When transmission diversity transmission is performed using two transmission antennas as non-space division multiplex transmission, the data selection switches 23b, 23c, and 23d are input from the non-space division multiplex transmission processing unit 25. A control signal that does not output a signal input from the non-space division multiplex transmission processing unit 25 is output to the remaining one.

  As described above, the space division multiplex transmission processing unit 24 operates in accordance with the control signal input from the transmission control unit 20, and when notified to perform space division multiplex transmission, the space division multiplex transmission processing unit 24 performs space division on the input signal. Multiplex transmission processing is performed and output. In addition, the non-space division multiplex transmission processing unit 25 operates according to the control signal input from the transmission control unit 20, and when notified to perform non-space division multiplex transmission, Performs division multiplex transmission processing and outputs. At least one of the frequency conversion units 26a to 26c upconverts the input signal to a radio frequency and outputs the radio signal. The up-converted transmission signal is transmitted via at least one of the antennas 27a to 27c.

  In the first embodiment, for convenience of explanation of the function, a configuration in which the space division multiplex transmission processing unit 24 and the non-space division multiplex transmission processing unit 25 are divided into two independent blocks is shown. Is not limited to this. That is, generality is not lost even if these processing units are shared as one block. In this case, the necessary blocks associated with each are controlled to operate. Further, regarding non-space division multiplex transmission, even if a single antenna or means such as transmission diversity is used, the transmission frame length does not change, so the present invention does not lose generality.

  Next, the operation of the wireless transmission device according to the first embodiment configured as described above will be described with reference to the flowchart shown in FIG. This flowchart shows processing for one transmission frame. First, the number of symbols required for information transmission is calculated from the data transmission amount, the modulation scheme, and the coding rate (step P1). Next, the number of symbols required for each is recalculated according to the space division multiplexing number (step P2). Here, the number of symbols transmitted from one transmission antenna is calculated, and the number of symbols is calculated for all transmission schemes having different space division multiplexing numbers. For example, when the maximum space division multiplexing number is 4, a transmission method in which the space division multiplexing number is 4, a transmission method in which the space division multiplexing number is 3, a transmission method in which the space division multiplexing number is 2, The number of symbols is calculated for each transmission scheme having a division multiplexing number of one.

  Next, the number of pilot signal symbols of one transmission frame is added (step P3). Here, the number of symbols of the pilot signal, which differs depending on the number of space division multiplexing, is added to the number of symbols necessary for transmission of information calculated in step P2 according to the number of space division multiplexing. Based on the above calculation result, the transmission frame length is calculated (step P4). The transmission frame length is calculated from the number of symbols calculated in step P3. Here, it is determined whether or not the transmission frame length has been calculated for all transmission methods (step P5), and if the transmission frame has not been calculated for all transmission methods, the process proceeds to step P2. On the other hand, when transmission frames have been calculated for all transmission methods, the transmission method with the shortest transmission frame length is selected (step P6). Transmission is performed using the transmission method selected here, and the processing for the transmission frame ends. Then, the process from step P1 is performed again for the next transmission frame.

  It is also possible to omit the step P4 in the above flowchart and select a transmission method with the smallest number of symbols in the transmission frame based on the number of symbols in the direct transmission frame.

  As described above, according to the first embodiment, it is possible to select a transmission method that minimizes the transmission frame length when sending the same amount of transmission data, so that the communication time required for data communication is short. As a result, communication efficiency can be improved.

(Second Embodiment)
As shown in FIG. 5, the radio transmission apparatus (transmission unit) according to the second embodiment includes a transmission frame length calculation unit 21 and a transmission method selection unit 22 in the configuration of the first embodiment shown in FIG. The transmission data amount calculation unit 30 and the transmission method selection unit 31 are replaced. The transmission data amount calculation unit 30 constitutes a calculation unit. Other configurations are the same as those of the wireless transmission device according to the first embodiment.

  In the second embodiment, the transmission frame length is assumed to be fixed or predetermined by the system. In the first embodiment, the transmission frame length that is the shortest when the same transmission data amount is sent is selected. On the other hand, in the second embodiment, when the transmission frame length is given from the upper layer, the transmission data amount calculation unit 30 shown in FIG. 5 receives the modulation scheme and coding rate input from the transmission control unit 20. Based on the transmission frame length, the amount of transmittable data transmission is calculated when performing space division multiplex transmission and non-space division multiplex transmission.

  Similar to the first embodiment described above, a section that can be used for transmission is calculated according to the transmission frame length by excluding the section for transmitting the pilot signal from the entire section of the transmission frame. If the number of symbols that can be transmitted in the calculated interval is S, the modulation scheme is M, the coding rate is R, and the number of space division multiplexing is N, the transmittable data transmission amount is as follows.

算出した結果は伝送方式選択部３１に出力され、伝送方式選択部３１は、最もデータ伝送量が多い伝送方式を選択して、選択結果を示すデータを送信制御部２０に出力する。

The calculated result is output to the transmission method selection unit 31. The transmission method selection unit 31 selects the transmission method having the largest data transmission amount and outputs data indicating the selection result to the transmission control unit 20.

  Therefore, when the transmission frame length is given from the upper layer, the transmission method that can send the largest amount of data transmission is selected.

  FIG. 6 is a flowchart illustrating the operation of the wireless transmission device according to the second embodiment. Here, the transmission method is selected based on the transmittable data transmission amount. This flowchart shows processing for one transmission frame. First, the data transmission frame length is calculated from the transmission frame length and the length of the pilot signal section (step Q1). Here, the data transmission frame length indicates a section that can be used for transmission of a data signal excluding a pilot signal section in the transmission frame. In addition, the data transmission frame length is calculated according to different space division multiplexing numbers using different pilot signals. In addition, calculation is performed so that the unit of the calculated data transmission frame length is the number of symbols. Next, the transmittable data transmission amount is calculated from the data transmission frame length, modulation scheme, coding rate, and space division multiplexing number (step Q2). Here, the transmittable data transmission amount is the total transmittable data transmission amount according to the number of space division multiplexing.

  Here, it is determined whether or not the data transmission amount that can be transmitted for all transmission methods has been calculated (step Q3). If the data transmission amount that can be transmitted for all transmission methods has not been calculated, step Q1 is determined. Migrate to On the other hand, when calculation of the transmittable data transmission amount is completed for all the transmission methods, the transmission method having the largest transmittable data transmission amount is selected (step Q4). Here, transmission is performed using the selected transmission method, and the processing for the transmission frame ends. Then, the process is repeated from step Q1 for the next transmission frame.

  As described above, according to the second embodiment, it is possible to select a transmission method that maximizes the amount of data transmission when the transmission frame length is fixed or predetermined by the system. It becomes high and it becomes possible to aim at the efficiency improvement of communication.

(Third embodiment)
In the first embodiment described above, the transmission method that minimizes the transmission frame length is selected for each transmission frame. On the other hand, in the third embodiment, the operation of selecting the transmission method is stopped while transmitting some predetermined transmission frames. That is, for each of several predetermined transmission frames, the transmission frame length is calculated for each transmission method, and the transmission method with the shortest transmission frame length is selected.

  FIG. 7 is a flowchart in a case where the switching counter for stopping the selection of the transmission method is made to function during a predetermined number of transmission frames. Here, an example in which the operation of the switching counter is added to the flowchart shown in FIG. As shown in FIG. 7, first, the number of symbols required for information transmission is calculated from the data transmission amount, the modulation scheme, and the coding rate (step R1). Next, the number of symbols necessary for each is recalculated according to the number of space division multiplexing (step R2). Here, the number of symbols transmitted from one transmission antenna is calculated, and the number of symbols is calculated for all transmission schemes having different space division multiplexing numbers. For example, when the maximum space division multiplexing number is 4, a transmission method in which the space division multiplexing number is 4, a transmission method in which the space division multiplexing number is 3, a transmission method in which the space division multiplexing number is 2, The number of symbols is calculated for each transmission scheme having a division multiplexing number of one.

  Next, the number of pilot signal symbols of one transmission frame is added (step R3). Here, the number of symbols of the pilot signal, which differs depending on the number of space division multiplexing, is added to the number of symbols necessary for transmitting the information calculated in step R2 according to the number of space division multiplexing. Based on the above calculation result, the transmission frame length is calculated (step R4). The transmission frame length is calculated from the number of symbols calculated in step R3. Here, it is determined whether transmission frames have been calculated for all transmission methods (step R5). If transmission frames have not been calculated for all transmission methods, the process proceeds to step R2. On the other hand, when transmission frames have been calculated for all transmission methods, the transmission method with the shortest transmission frame length is selected (step R6). Here, transmission is performed using the selected transmission method.

  Thus, after setting the transmission method in step R6, 1 is added to n whose initial value is 0 (step R7), and it is determined whether or not the added n is equal to arbitrarily set N. (Step R8). As a result of this determination, if the added n is equal to the arbitrarily set N, n is set to 0 (step R9), and the processing is performed from step R1 on the transmission frame. On the other hand, as a result of the determination, if the added n is not equal to the arbitrarily set N, the transmission method selection process is not performed for the transmission frame at that time, and 1 is added to n and again n Is equal to the arbitrarily set N.

  When the data transmission amount is constant to some extent over several transmission frames, according to the third embodiment, selection can be performed in units of N without frequently selecting a transmission method. Become. In the above description, the case where the transmission frame length is calculated and the transmission method with the shortest transmission frame length is selected corresponding to the first embodiment has been described. As in this embodiment, the present invention can also be applied to the case where the data transmission amount is calculated according to the transmission frame length and the transmission method having the largest data transmission amount is selected.

(Fourth embodiment)
As shown in FIG. 8, the wireless transmission device (transmission unit) according to the fourth embodiment has a configuration in which a reference information generation / holding unit 40 is added to the configuration of the first embodiment shown in FIG. take. Other configurations are the same as those of the wireless transmission device according to the first embodiment shown in FIG. In the fourth embodiment, the reference information generating / holding unit 40 has a reference signal and can select it as an index.

  In FIG. 8, the reference information generating / holding unit 40 generates and holds a method to be selected as a table shown in FIG. 9 in advance according to the transmission data amount or the transmission frame length. FIG. 9A shows an example of the reference information. When selecting the transmission method based on the transmission frame length, select the transmission method A if the transmission frame length L is smaller than L1, and select the transmission method B if the transmission frame length L is smaller than L2 and greater than or equal to L1, If the transmission frame length L is smaller than L3 and greater than or equal to L2, the reference information is configured from a table in which the transmission method C is selected, and if the transmission frame length L is greater than or equal to L3, the transmission method D is selected. When the transmission method is selected based on the transmission data amount, as shown in FIG. 9B, the transmission method A is selected if the transmission data amount M is smaller than M1, and the transmission data amount M is smaller than M2 and M1. If the transmission data amount M is smaller than M3 and greater than or equal to M2, the transmission method C is selected. If the transmission data amount M is equal to or greater than M3, the transmission method D is selected. The reference information is composed.

  In FIG. 9, for example, transmission method A is normal transmission with space division multiplexing number 1, transmission method B is space division multiplexing transmission with space division multiplexing number 2, and transmission method C is space division multiplexing transmission and transmission with space division multiplexing number 3. System D can be a space division multiplexing transmission with a space division multiplexing number of four. In the first and second embodiments, the basic method is to calculate the transmission frame length and the data transmission amount for each transmission frame. However, in the fourth embodiment, the frequency of calculation is obtained by holding as a reference signal. Can be reduced. Although the generation process is shown here, the reference signal may be stored in advance in storage means (memory) or the like and read out as necessary.

(Fifth embodiment)
In the fifth embodiment, it is assumed that the wireless transmission devices according to the first to fourth embodiments operate as a base station or a centralized control station of a communication system. The base station or the central control station according to the fifth embodiment performs broadcast transmission of the reference information shown in the fourth embodiment to the mobile station. The mobile station wirelessly transmits information to the base station or the central control station using a transmission scheme based on the reference information received from the base station or the central control station.

  That is, if the communication between the base station or the centralized control station and the mobile station is one-to-one communication, there is no need to broadcast the reference information. However, as the number of mobile stations existing in the area controlled by the base station or centralized control station increases, each mobile station notifies the base station or centralized control station of the transmission method determined by the mobile station. The control station frequently changes the transmission method for each mobile station, which increases the complexity of the communication system.

  For this reason, in the fifth embodiment, the base station or the centralized control station broadcasts and transmits reference information regarding selection of a transmission method to each mobile station. Each mobile station includes the radio transmission device according to any of the above, and a radio reception device that receives reference information as information indicating a transmission method transmitted from the radio transmission device of the base station or the centralized control station. The wireless transmission device of the mobile station wirelessly transmits information using the received transmission method. Thus, since the mobile station wirelessly transmits information based on the received reference information (information indicating the transmission method), it is possible to improve the uniformity of the control of the communication system and avoid complicated processing. Become.

It is a block diagram which shows schematic structure of a radio | wireless communication apparatus. It is a block diagram which shows schematic structure of a radio | wireless transmitter. It is a block diagram which shows schematic structure of a radio | wireless transmitter. It is a flowchart which shows operation | movement of a radio | wireless transmitter. It is a block diagram which shows schematic structure of a radio | wireless transmitter. It is a flowchart which shows operation | movement of a radio | wireless transmitter. It is a flowchart which shows operation | movement of a radio | wireless transmitter. It is a block diagram which shows schematic structure of a radio | wireless transmitter. (A) It is a figure which shows the table which a radio | wireless transmission apparatus has. (B) It is a figure which shows the table which a radio | wireless transmission apparatus has. It is a block diagram which shows schematic structure of a radio | wireless communication apparatus. It is a figure which shows the structure of a transmission frame. It is a figure which shows the structure of a transmission frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication apparatus 2 Transmission part 3 Reception part 4 Transmission / reception control part 5 Duplexer 6-1 to 6-n Antenna 7 Transmitter 8 Handset 9 Display 10 Dial key 20 Transmission control part 21 Transmission frame length calculation part 22 Transmission system Selection unit 23a-23d Data selection switch 24 Spatial division multiplexing transmission processing unit 25 Non-space division multiplexing transmission processing unit 26a-26c Frequency conversion unit 27a-27c Antenna 30 Transmission data amount calculation unit 31 Transmission method selection unit 40 Reference information generation / holding Part

Claims (10)

A wireless transmission device comprising a plurality of transmission antennas, selecting any one transmission method from a plurality of transmission methods, and wirelessly transmitting information by the selected transmission method,
A first transmitter that spatially multiplexes and transmits information using the plurality of antennas;
A second transmitter that transmits information without spatial division multiplexing using a plurality of or a single antenna; and
A calculation unit for calculating the length of a transmission frame for each transmission method;
A transmission method selection unit that selects a transmission method with the shortest length of the calculated transmission frame, and
One of the first transmission unit and the second transmission unit wirelessly transmits information by the selected transmission method. A wireless transmission device comprising a plurality of transmission antennas, selecting any one transmission method from a plurality of transmission methods, and wirelessly transmitting information by the selected transmission method,
A first transmitter that spatially multiplexes and transmits information using the plurality of antennas;
A second transmitter that transmits information using a plurality of or a single antenna without space division multiplexing;
A calculation unit that calculates the number of symbols included in the transmission frame for each transmission method;
A transmission method selection unit that selects a transmission method with the calculated number of symbols being the minimum,
One of the first transmission unit and the second transmission unit wirelessly transmits information by the selected transmission method.   The calculation unit calculates the length of the transmission frame or the number of symbols based on information indicating the amount of transmission data, information indicating the number of space division multiplexing, modulation scheme information, and coding scheme information. The wireless transmission device according to claim 1 or 2. A wireless transmission device comprising a plurality of transmission antennas, selecting any one transmission method from a plurality of transmission methods, and wirelessly transmitting information by the selected transmission method,
A first transmitter that spatially multiplexes and transmits information using the plurality of antennas;
A second transmitter that transmits information using a plurality of or a single antenna without space division multiplexing;
A calculation unit that calculates a transmission amount of transmission data included in a transmission frame of a certain length for each transmission method;
A transmission method selection unit that selects a transmission method with the largest transmission amount of the calculated transmission data, and
One of the first transmission unit and the second transmission unit wirelessly transmits information by the selected transmission method.   The calculation unit calculates a transmission amount of the transmission data based on information indicating a length of a transmission frame, information indicating a spatial division multiplexing number, modulation scheme information, and encoding scheme information. 4. The wireless transmission device according to 4.   And a control unit that controls a frequency at which the calculation unit calculates the length of the transmission frame, the number of symbols, or a transmission amount of the transmission data, and a frequency at which the transmission method selection unit selects the transmission method. The wireless transmission device according to claim 1, wherein: The transmission method selection unit
A table associating a transmission method according to the length of the transmission frame, the number of symbols, or the transmission amount of the transmission data;
2. An extraction unit that extracts a transmission method corresponding to the length of the transmission frame, the number of symbols, or the transmission amount of the transmission data calculated by the calculation unit from the table. The wireless transmission device according to claim 6.   The wireless transmission device according to claim 7, wherein either the first transmission unit or the second transmission unit wirelessly transmits information indicating the extracted transmission method. A wireless transmission device according to any one of claims 1 to 8,
A wireless reception device that receives information indicating the transmission method transmitted from the wireless transmission device according to claim 8,
The wireless transmission device wirelessly transmits information using the transmission method received by the wireless reception device, using either the first transmission unit or the second transmission unit. A wireless communication system comprising: a base station or a centralized control station including the wireless transmission device according to claim 8; and a mobile station according to claim 9.

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