JP2006319473A - Transmitting method and receiving method, and transmitting device, receiving device and communication system using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve transmission efficiency as to a transmitting method and a receiving method of transmitting signals from a plurality of antennas and receiving signals by the plurality of antennas, and a transmitting device, a receiving device and a communication system using them. <P>SOLUTION: A pilot insertion section 78 inserts a known signal into some of a plurality of subcarriers for at least a Legacy preamble and data of a packet signal having a MIMO preamble and data arranged behind the Legacy preamble, a Legacy signal, and a MIMO signal to use a plurality of subcarriers respectively. The pilot insertion section 78 inserts the known signal into some of subcarriers of the Legacy signal so that the number of subcarriers of the MIMO signal arranged in a plurality of symbols is larger than the number of subcarriers corresponding to an unknown signal of the Legacy signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission technique and a reception technique, and more particularly to a transmission method and a reception method for transmitting signals from a plurality of antennas and receiving signals by a plurality of antennas, and a transmission apparatus, a reception apparatus and a communication system using them.

  An OFDM (Orthogonal Frequency Division Multiplexing) modulation scheme, which is one of the multicarrier schemes, is a communication scheme that enables high-speed data transmission and is strong in a multipath environment. This OFDM modulation scheme is applied to IEEE802.11a, g and HIPERLAN / 2, which are standardized standards for wireless LAN (Local Area Network). A packet signal in such a wireless LAN is generally transmitted via a transmission path environment that fluctuates with time, and is affected by frequency selective fading. Therefore, a receiver generally performs transmission path estimation dynamically. Execute.

In order for the receiving apparatus to perform transmission path estimation, two types of known signals are provided in the packet signal. One is a known signal provided for all carriers at the beginning of the packet signal, which is a so-called preamble or training signal. The other is a known signal provided for some of the carriers in the data interval of the packet signal, which is a so-called pilot signal (see, for example, Non-Patent Document 1).
Sine Coleri, Mustafa Ergen, Anuj Puri, and Ahmad Bahai, “Channel Estimation Techniques Based on Pilot Arrangement in OFDM Systems”, IbnEnts. 48, no. 3, pp. 223-229, Sept. 2002.

  One technique for effectively using frequency resources in wireless communication is an adaptive array antenna technique. The adaptive array antenna technology controls the directivity pattern of an antenna by controlling the amplitude and phase of a signal to be processed in each of a plurality of antennas. One technique for increasing the data rate using such an adaptive array antenna technique is a MIMO (Multiple Input Multiple Output) system. In the MIMO system, the transmission device and the reception device each include a plurality of antennas, and channels corresponding to the respective antennas are set. That is, the data rate is improved by setting channels up to the maximum number of antennas for communication between the transmission device and the reception device. If such a MIMO system is combined with an OFDM modulation scheme, the data rate is further increased.

  In the MIMO system, the data rate can be adjusted by increasing or decreasing the number of antennas to be used for data communication. Furthermore, the adjustment of the data rate is made in more detail by applying adaptive modulation. In order to reliably execute such adjustment of the data rate, the transmission device acquires information (hereinafter referred to as “rate information”) on the data rate suitable for the wireless transmission path between the transmission device and the reception device. It is desirable to do. On the other hand, when the rate information is not periodically transmitted in the MIMO system, the transmission device transmits a signal for requesting transmission of the rate information (hereinafter referred to as “rate request signal”) to the reception device.

  Also, combinations of antenna directivity patterns in the transmission apparatus and the reception apparatus in the MIMO system are as follows, for example. One is a case where the antenna of the transmission device has an omni pattern and the antenna of the reception device has a pattern in adaptive array signal processing. Another is the case where both the antenna of the transmitting device and the antenna of the receiving device have patterns in adaptive array signal processing. The former can simplify the system, but the latter can improve the characteristics because the directivity pattern of the antenna can be controlled in more detail. In the latter case, in order for the transmission apparatus to perform adaptive array signal processing for transmission, it is necessary to previously receive a known signal for channel estimation from the reception apparatus. In order to improve the accuracy of adaptive array antenna control, it is desirable that the transmission apparatus acquires respective transmission path characteristics between the plurality of antennas included in the transmission apparatus and the plurality of antennas included in the reception apparatus. Therefore, the receiving apparatus transmits a known signal for transmission path estimation from all antennas. Hereinafter, a known signal for channel estimation transmitted from a plurality of antennas is referred to as a “training signal” regardless of the number of antennas to be used for data communication.

  Under such circumstances, the present inventor has come to recognize the following problems. As described above, pilot signals are included in some of the carriers, and effective information cannot be transmitted using the pilot signals, so that transmission efficiency decreases. On the other hand, in order to maintain transmission quality, it is necessary to transmit a pilot signal. Therefore, it is desired to improve transmission efficiency while suppressing deterioration of transmission quality.

  The present invention has been made in view of these circumstances, and an object thereof is to provide a transmission technique and a reception technique that improve transmission efficiency.

  In order to solve the above-described problem, a transmitting apparatus according to an aspect of the present invention provides a second control signal behind a first preamble, a first control signal, and a second control signal that should use a plurality of subcarriers, respectively. The second preamble and data to be used by a number of subcarriers different from the number of subcarriers, respectively, and the second preamble to be controlled by the second control signal and at least the first of the packet signals for arranging the data An insertion unit that inserts a known signal in some subcarriers with respect to the control signal and data, and a generation unit that generates a packet signal by including the first control signal and data in which the known signal is inserted by the insertion unit With. The inserting unit controls the first control so that the number of subcarriers corresponding to the unknown signal in the second control signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. A known signal is inserted into some subcarriers of the signal.

  According to this aspect, the known signal is such that the number of subcarriers corresponding to the unknown signal in the second control signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. Therefore, the transmission efficiency in the second control signal can be improved over the transmission efficiency in the first control signal. In addition, since the second preamble is arranged after the second control signal, it is possible to suppress deterioration in transmission quality.

  Of the packet signal generated by the generation unit, the number of subcarriers used in the second preamble and data is greater than the number of subcarriers used in the first preamble, the first control signal, and the second control signal. The insertion unit is configured such that the number of subcarriers corresponding to the unknown signal in the second control signal is equal to the number of subcarriers corresponding to the unknown signal in the data. Thus, a known signal may be inserted into some subcarriers in the data. In this case, the known signal is inserted so that the number of subcarriers corresponding to the unknown signal in the second control signal is equal to the number of subcarriers corresponding to the unknown signal in the data. Unknown signals can be transmitted by the same number of subcarriers as data using more subcarriers than two control signals, and transmission efficiency can be improved.

  You may further provide the interleaving part which performs an interleaving with respect to an unknown signal among 1st control signals. The interleaving unit performs interleaving on a portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and out of the unknown signal in the second control signal. For the portion of the first control signal that does not correspond to the unknown signal, the arrangement of the first control signal on the subcarrier that should correspond to the known signal may be performed. In this case, the same interleaving unit can be used for the first control signal and the second control signal.

  You may further provide the interleaving part which performs the interleaving with respect to an unknown signal among data. The interleaving unit may perform interleaving on the unknown signal in the second control signal. In this case, the same interleave unit can be used for the second control signal and the data.

  When generating the packet signal, the generation unit arranges the second control signal in a plurality of symbols, and the insertion unit performs second control arranged in the plurality of symbols as an unknown signal among the second control signals. Of the signals, an unknown signal of at least the rear symbols may be processed. In this case, even if the second control signal is arranged in a plurality of symbols, it can be dealt with.

  The generating unit arranges the second control signal in a plurality of symbols when generating the packet signal, and the interleaving unit arranges the second control signal arranged in the plurality of symbols as an unknown signal in the second control signal. Among them, an unknown signal in at least the rear symbol may be processed. In this case, even if the second control signal is arranged in a plurality of symbols, it can be dealt with.

  The insertion unit may insert a known signal different from the known signal to be inserted into the first control signal in the front symbol among the second control signals arranged in the plurality of symbols. In this case, according to the value of the known signal, it can be notified whether it is the second control signal.

  Another aspect of the present invention is a receiving device. This apparatus uses a number of subcarriers different from the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal that should use a plurality of subcarriers, respectively. A second preamble to be data, a second preamble that is controlled by a second control signal, a reception unit that receives a packet signal in which the data is arranged, and at least a first of the packet signals received by the reception unit An extraction unit that extracts a control signal and a known signal inserted in data, and a deinterleaving unit that performs deinterleaving on the non-known signal of the first control signal from which the known signal is extracted by the extraction unit. In the second control signal in the packet received by the receiving unit, the number of subcarriers corresponding to the unknown signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. The deinterleaving unit performs deinterleaving on the portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and the second control signal Among the unknown signals in, a portion that does not correspond to the unknown signal in the first control signal is combined with the portion that has been deinterleaved.

  According to this aspect, the known signal is such that the number of subcarriers corresponding to the unknown signal in the second control signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. Therefore, the transmission efficiency in the second control signal can be improved over the transmission efficiency in the first control signal. In addition, since the second preamble is arranged after the second control signal, it is possible to suppress deterioration in transmission quality.

  Yet another embodiment of the present invention is also a receiving device. This apparatus uses a number of subcarriers larger than the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal, each of which should use a plurality of subcarriers. A second preamble to be data, a second preamble that is controlled by a second control signal, a reception unit that receives a packet signal in which the data is arranged, and at least a first of the packet signals received by the reception unit An extraction unit that extracts a control signal and a known signal inserted into the data, and a deinterleaving unit that performs deinterleaving on the non-known signal of the data from which the known signal is extracted by the extraction unit. In the second control signal in the packet received by the receiving unit, the number of subcarriers corresponding to the unknown signal is defined to be equal to the number of subcarriers corresponding to the unknown signal in the data. The deinterleaving unit performs deinterleaving on the unknown signal in the second control signal.

  According to this aspect, the known signal is inserted so that the number of subcarriers corresponding to the unknown signal in the second control signal is equal to the number of subcarriers corresponding to the unknown signal in the data. Therefore, the unknown signal can be transmitted by the same number of subcarriers as data using more subcarriers than the second control signal, and the transmission efficiency can be improved.

  Among the packet signals received by the receiving unit, the second control signal is arranged in a plurality of symbols, and the deinterleaving unit is a second signal arranged in the plurality of symbols as an unknown signal in the second control signal. Of the control signals, an unknown signal at least in the rear symbol may be processed. An extraction part may extract the known signal different from the known signal inserted in the 1st control signal in the symbol of the front part among the 2nd control signals arranged in a plurality of symbols.

  Yet another embodiment of the present invention is a transmission method. This method uses a number of subcarriers different from the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal, each of which should use a plurality of subcarriers. Of the second preamble to be data and the second preamble to be controlled by the second control signal and the packet signal in which the data is arranged, at least for the first control signal and the data, some subcarriers A transmission method for generating a packet signal by inserting a known signal, wherein the number of subcarriers corresponding to an unknown signal among the second control signals arranged in a plurality of symbols is equal to that of the first control signal. A known signal is inserted into some subcarriers of the first control signal so as to be larger than the number of subcarriers corresponding to the unknown signal.

  Among the generated packet signals, the number of subcarriers used in the second preamble and data is larger than the number of subcarriers used in the first preamble, the first control signal, and the second control signal. Of the data so that the number of subcarriers corresponding to the unknown signal in the second control signal is equal to the number of subcarriers corresponding to the unknown signal in the data. A known signal may be inserted into some subcarriers.

  While interleaving is performed on the unknown signal in the first control signal, interleaving is performed on a portion corresponding to the unknown signal in the first control signal among the unknown signals in the second control signal. A subcarrier to be executed and corresponding to a known signal in the first control signal for a portion of the unknown signal in the second control signal that does not correspond to the unknown signal in the first control signal You may perform the placement. Interleaving may be performed on the unknown signal in the second control signal while performing interleaving on the unknown signal in the data. When generating the packet signal, the second control signal is arranged in a plurality of symbols, and at least a rear symbol of the second control signals arranged in the plurality of symbols as an unknown signal in the second control signal. Of these, unknown signals may be processed. Of the second control signals arranged in a plurality of symbols, a known signal different from the known signal to be inserted into the first control signal may be inserted in the front symbol.

  Yet another embodiment of the present invention is a reception method. This method uses a number of subcarriers different from the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal, each of which should use a plurality of subcarriers. A second preamble and data to be received, a second preamble controlled by a second control signal, a step of receiving a packet signal for arranging the data, and at least a first control signal and data among the received packet signals Extracting a known signal inserted into the first control signal and performing deinterleaving on the non-known signal of the first control signal from which the known signal is extracted. In the second control signal in the received packet in the receiving step, the number of subcarriers corresponding to the unknown signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. And the step of performing deinterleaving performs deinterleaving on a portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and Of the unknown signal in the second control signal, the portion that does not correspond to the unknown signal in the first control signal is combined with the portion that has been deinterleaved.

  Yet another embodiment of the present invention is also a reception method. This method uses a number of subcarriers larger than the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal, which should use a plurality of subcarriers, respectively. A second preamble and data to be received, a second preamble controlled by a second control signal, a step of receiving a packet signal for arranging the data, and at least a first control signal and data among the received packet signals Extracting the known signal inserted into the data, and performing deinterleaving on the non-known signal of the data from which the known signal is extracted. In the second control signal in the received packet in the receiving step, the number of subcarriers corresponding to the unknown signal is defined to be equal to the number of subcarriers corresponding to the unknown signal in the data. In the step of performing deinterleaving, deinterleaving is performed on the unknown signal in the second control signal.

  Of the packet signals received in the receiving step, the second control signal is arranged in a plurality of symbols, and the step of executing deinterleaving is arranged in the plurality of symbols as an unknown signal in the second control signal. Of the second control signal, the unknown signal at least in the rear symbol may be processed. The step of performing deinterleaving may extract a known signal different from the known signal inserted in the first control signal in the front symbol among the second control signals arranged in a plurality of symbols.

  Yet another embodiment of the present invention is a communication system. In this communication system, a number of subcarriers different from the number of subcarriers in the second control signal are respectively provided behind the first preamble, the first control signal, and the second control signal that should use a plurality of subcarriers. The second preamble and data to be used and the second preamble to be controlled by the second control signal and the packet signal in which the data is arranged are interleaved with respect to the unknown signal of the first control signal. , At least the first control signal and the data, by inserting a known signal into some subcarriers to generate a packet signal, and at least the first control signal and the data among the received packet signals The inserted known signal is extracted, and deinterleaving is performed on the unknown signal of the first control signal from which the known signal is extracted. And a communication apparatus. The transmission apparatus performs the first control so that the number of subcarriers corresponding to the unknown signal in the second control signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. Interleaving is performed on the portion corresponding to the unknown signal in the first control signal among the unknown signal in the second control signal and the means for inserting the known signal into some subcarriers of the signal However, a portion of the non-known signal in the second control signal that does not correspond to the non-known signal in the first control signal is transferred to a subcarrier that should correspond to the known signal in the first control signal. Means for performing the arrangement of The receiving apparatus performs deinterleaving on the portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and the unknown device in the second control signal Of these, the portion that does not correspond to the unknown signal in the first control signal is combined with the portion that has been deinterleaved.

  Yet another aspect of the present invention is also a communication system. In this communication system, a number of subcarriers larger than the number of subcarriers in the second control signal are respectively placed behind the first preamble, the first control signal, and the second control signal that should use a plurality of subcarriers, respectively. The second preamble to be used and the data, and the second preamble to be controlled by the second control signal and the packet signal in which the data is arranged, are interleaved with respect to the unknown signal of the data, and at least the second preamble A transmission device that generates a packet signal by inserting known signals into some subcarriers with respect to one control signal and data, and at least the first control signal and data inserted in the received packet signal A receiving device that extracts a known signal and performs deinterleaving on the unknown signal of the data from which the known signal is extracted; Provided. The transmitting apparatus includes means for inserting a known signal into some subcarriers of the data so as to be equal to the number of subcarriers corresponding to the unknown signal of the second control signal, and a second control signal. Means for performing interleaving on the unknown signals. The receiving device performs deinterleaving on the unknown signal in the second control signal.

  The transmitting apparatus may insert a known signal different from the known signal to be inserted into the first control signal in the front symbol among the second control signals arranged in the plurality of symbols.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, transmission efficiency can be improved.

  Before describing the present invention in detail, an outline will be described. An embodiment of the present invention relates to a MIMO system configured by two radio apparatuses (hereinafter referred to as “first radio apparatus” and “second radio apparatus” for convenience). Both the first wireless device and the second wireless device in the MIMO system perform adaptive array signal processing. In addition, the MIMO system changes the data rate by changing the values of the number of antennas, the modulation scheme, and the error correction coding rate. At that time, the transmitting-side radio apparatus transmits a rate request signal to the receiving-side radio apparatus. For example, when the first wireless device transmits data to the second wireless device, the first wireless device transmits a rate request signal to the second wireless device.

  A packet signal transmitted by the first radio apparatus and the second radio apparatus is a signal corresponding to only the MIMO system after the signal corresponding to the communication system not compatible with the MIMO system (hereinafter referred to as “conventional system”). Place. That is, the packet format includes a preamble corresponding to the conventional system (hereinafter referred to as “Legacy preamble”), a control signal corresponding to the conventional system (hereinafter referred to as “Legacy signal”), and a control signal corresponding to the MIMO system (hereinafter referred to as “Legacy signal”). Hereinafter, a “MIMO signal”, a preamble corresponding to the MIMO system (hereinafter referred to as “MIMO preamble”), and data corresponding to the MIMO system (hereinafter simply referred to as “data”) are arranged. In this way, the presence of the packet signal can be recognized even by a radio apparatus compatible only with the conventional system by arranging the legacy preamble or the like at the head part. As a result, a radio apparatus compatible only with the conventional system does not perform packet signal transmission, so that collision of packet signals can be reduced. Note that the data rate is changed in the data in the packet signal and not in other portions. For example, an error-resistant modulation scheme or the like is used for the MIMO signal.

  The number of subcarriers used in the MIMO preamble and data is larger than the number of subcarriers used in the Legacy preamble, Legacy signal, and MIMO signal. In addition, in the legacy signal and data, a pilot signal is arranged on a part of the plurality of subcarriers in order to suppress deterioration in transmission quality. Here, if pilot signals are arranged on some subcarriers in the MIMO signal, the number of subcarriers that can substantially transmit information in the MIMO signal is smaller than that in data.

  The radio apparatus according to the present embodiment does not place a pilot signal in the MIMO signal. That is, in the MIMO signal, information is transmitted using all subcarriers. As a result, a decrease in transmission efficiency can be suppressed. Note that, as described above, the MIMO signal uses a modulation scheme that is resistant to errors, so that deterioration of transmission quality can be reduced even without a pilot signal. Further, since the MIMO preamble is arranged at the subsequent stage of the MIMO signal, the influence due to the absence of the pilot signal does not propagate there. Furthermore, the number of subcarriers used by the MIMO signal and the number of subcarriers used by portions other than the pilot signal in the data are defined to be equal. Therefore, common interleaving and deinterleaving can be used for both.

  FIG. 1 shows a spectrum of a multicarrier signal according to an embodiment of the present invention. In particular, FIG. 1 shows the spectrum of a signal in the OFDM modulation scheme. One of a plurality of carriers in the OFDM modulation system is generally called a subcarrier, but here, one subcarrier is designated by a “subcarrier number”. In the MIMO system, 56 subcarriers from subcarrier numbers “−28” to “28” are defined. The subcarrier number “0” is set to null in order to reduce the influence of the DC component in the baseband signal. On the other hand, in the conventional system, 52 subcarriers from subcarrier numbers “−26” to “26” are defined. That is, it complies with the IEEE802.11a and g standards. Each subcarrier is modulated by a variably set modulation method. As a modulation method, any one of BPSK (Binary Phase Shift Keying), QSPK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and 64QAM is used.

  Also, convolutional coding is applied to these signals as an error correction method. The coding rate of convolutional coding is set to 1/2, 3/4, and the like. Furthermore, the number of antennas used in the MIMO system is variably set. As a result, the data rate is also variably set by variably setting the modulation scheme, coding rate, and number of antennas. Here, the “data rate” may be determined by any combination thereof, or may be determined by one of them. Hereinafter, as described above, information on the data rate is referred to as “rate information”, but the rate information includes values of a modulation scheme, a coding rate, and the number of antennas. Here, unless otherwise required, values of the modulation scheme, coding rate, and number of antennas are not described.

  FIG. 2 shows a configuration of the communication system 100 according to the embodiment of the present invention. The communication system 100 includes a first wireless device 10a and a second wireless device 10b collectively referred to as a wireless device 10. The first radio apparatus 10a includes a first antenna 12a, a second antenna 12b, a third antenna 12c, and a fourth antenna 12d, which are collectively referred to as an antenna 12, and the second radio apparatus 10b is collectively referred to as an antenna 14. A first antenna 14a, a second antenna 14b, a third antenna 14c, and a fourth antenna 14d are included. One of the first radio apparatus 10a and the second radio apparatus 10b corresponds to a transmission apparatus, and the other corresponds to a reception apparatus. One of the first radio apparatus 10a and the second radio apparatus 10b corresponds to a base station apparatus, and the other corresponds to a terminal apparatus.

  Before describing the configuration of the communication system 100, an outline of a MIMO system will be described. It is assumed that data is transmitted from the first radio apparatus 10a to the second radio apparatus 10b. The first radio apparatus 10a transmits different data from each of the first antenna 12a to the fourth antenna 12d. As a result, the data rate is increased. The second radio apparatus 10b receives data from the first antenna 14a to the fourth antenna 14d. Furthermore, the second radio apparatus 10b separates the received data by adaptive array signal processing and independently demodulates the data transmitted from each of the first antenna 12a to the fourth antenna 12d.

  Here, since the number of antennas 12 is “4” and the number of antennas 14 is also “4”, the combination of transmission paths between the antennas 12 and 14 is “16”. A transmission path characteristic between the i-th antenna 12i and the j-th antenna 14j is denoted by hij. In the figure, the transmission path characteristic between the first antenna 12a and the first antenna 14a is h11, the transmission path characteristic between the first antenna 12a and the second antenna 14b is h12, the second antenna 12b and the first antenna. 14a, the transmission path characteristic between the second antenna 12b and the second antenna 14b is h22, and the transmission path characteristic between the fourth antenna 12d and the fourth antenna 14d is h44. Has been. Note that transmission lines other than these are omitted for clarity of illustration.

  The second radio apparatus 10b operates such that data transmitted from the first antenna 12a to the second antenna 12b can be independently demodulated by adaptive array signal processing. Furthermore, the first radio apparatus 10a may also perform adaptive array signal processing from the first antenna 12a to the fourth antenna 12d. In this way, the first radio apparatus 10a on the transmission side also executes adaptive array signal processing to ensure space division in the MIMO system. As a result, interference between signals transmitted from the plurality of antennas 12 is reduced, so that data transmission characteristics can be improved.

  The first radio apparatus 10a transmits different data from the first antenna 12a to the fourth antenna 12d. The first radio apparatus 10a controls the number of antennas 12 to be used according to the rate and capacity of data to be transmitted. The first radio apparatus 10a controls the modulation scheme and the error correction coding rate. For example, if the capacity of data to be transmitted is large, “4” antennas 12 are used, and if the capacity of data to be transmitted is small, “2” antennas 12 are used. The first radio apparatus 10a refers to the rate information in the second radio apparatus 10b when determining the number of antennas 12 to be used, the modulation method, and the like. For example, when the second radio apparatus 10 b instructs reception using “2” antennas 14, the first radio apparatus 10 a uses “2” antennas 12. Furthermore, the first radio apparatus 10a performs adaptive array signal processing on the antenna 12 when transmitting data. Therefore, the first radio apparatus 10a receives a training signal from the second radio apparatus 10b in advance, and derives a transmission weight vector based on the training signal.

  Further, regardless of whether the first radio apparatus 10a is a training signal, the first radio apparatus 10a uses a plurality of subcarriers behind the legacy preamble, the legacy signal, and the MIMO signal, and the number of subcarriers in the MIMO signal. And a packet signal in which data of a MIMO preamble and data to be used is used. Here, the MIMO preamble and data are controlled by a MIMO signal. That is, information related to data is included in the MIMO signal. Further, the presence of the MIMO signal is transmitted to the second radio apparatus 10b that the MIMO preamble and data exist. Also, when generating the packet signal, the first radio apparatus 10a inserts a pilot signal into some subcarriers for at least the legacy signal and data while performing interleaving on the legacy signal and data. .

  Here, no pilot signal is inserted into the MIMO signal. In the first radio apparatus 10a, the number of subcarriers corresponding to signals other than the pilot signal of the MIMO signal (hereinafter referred to as “unknown signal”) is equal to the number of subcarriers corresponding to the unknown signal in the data. As shown, pilot signals are inserted into some subcarriers of the data.

  The second radio apparatus 10b performs adaptive array signal processing on the first antenna 14a to the fourth antenna 14d and receives data from the first radio apparatus 10a. As described above, the second radio apparatus 10b notifies the first radio apparatus 10a of rate information and transmits a training signal. The second radio apparatus 10b extracts at least the legacy signal and the pilot signal inserted into the data from the received packet signal regardless of whether it is a training signal or not, and the data from which the pilot signal is extracted is unknown. Perform deinterleaving on the signal. At this time, de-interleaving based on the same rule as that for data is also performed on the unknown signal of the MIMO signal. Note that the operations of the first radio apparatus 10a and the second radio apparatus 10b may be reversed.

  3A to 3C show packet format configurations in the communication system 100. FIG. FIG. 3A shows a packet format when the number of antennas 12 used is “2”. The upper part of the figure shows a packet signal transmitted from the first antenna 12a, and the lower part of the figure shows a packet signal transmitted from the second antenna 12b. “Legacy STS (Short Training Sequence)”, “Legacy LTS (Long Training Sequence)”, and “Legacy signal” are signals that are compatible with the conventional system as in the wireless LAN system compliant with the IEEE 802.11a standard. The aforementioned “Legacy preamble” corresponds to “Legacy STS” and “Legacy LTS” or one of them. “Legacy STS” is used for timing synchronization, AGC (Automatic Gain Control), and the like, and “Legacy LTS” is used for channel estimation. These are all known signals.

  The “Legacy signal” includes control information related to the conventional system. The “MIMO signal” and subsequent signals are signals specific to the MIMO system, and the “MIMO signal” includes control information corresponding to the MIMO system. “First MIMO-STS” and “second MIMO-STS” are used for timing synchronization, AGC, and the like, and “first MIMO-LTS” and “second MIMO-LTS” are used for channel estimation. These are all known signals. “First data” and “second data” are data to be transmitted. The above-mentioned “MIMO preamble” corresponds to “first MIMO-STS”, “second MIMO-STS”, “first MIMO-LTS” and “second MIMO-LTS”, or any one of them.

  Among the packet formats described above, the data rates for “first data” and “second data” are set to be variable. That is, the modulation scheme, coding rate, and number of antennas are controlled. On the other hand, the data rate in the “Legacy signal” and “MIMO signal” is set to be fixed. That is, since the information included in the “Legacy signal” and “MIMO signal” is important and required to be transmitted accurately, a low data rate is used. This can be said to be an error-resistant modulation scheme and coding rate. Furthermore, from “Legacy signal” to “MIMO signal”, “53” subcarriers are used. However, after “First MIMO-STS” and “Second MIMO-STS”, “56” subcarriers are used. It is used as shown in FIG. That is, the number of subcarriers used in the MIMO preamble and data is defined to be larger than the number of subcarriers used in the Legacy preamble, Legacy signal, and MIMO signal.

  Here, a pilot signal is inserted into subcarriers “-21”, “−7”, “7”, and “21” of “Legacy signal”, “first data”, and “second data”. Has been. That is, the same number of pilot signals are inserted. A pilot signal is inserted in the same subcarrier. Therefore, the number of subcarriers corresponding to the unknown signal included in “first data” and “second data” is “52”, and the number of subcarriers corresponding to the unknown signal included in “MIMO signal”. Is equal to

  FIG. 3B shows a packet format when “2” antennas 12 are used for data transmission, as in FIG. However, the aforementioned training signal is added. In the figure, the training signals correspond to “first MIMO-STS”, “first MIMO-LTS” to “fourth MIMO-STS”, “fourth MIMO-LTS”. Also, “first MIMO-STS”, “first MIMO-LTS” to “fourth MIMO-STS”, and “fourth MIMO-LTS” are transmitted from the first antenna 12 a to the fourth antenna 12 d, respectively. Note that the number of antennas 12 to which training signals are transmitted may be smaller than “4”. The “first MIMO-STS” to the “fourth MIMO-STS” are configured by patterns that reduce mutual interference.

  The same applies to “first MIMO-LTS” to “fourth MIMO-LTS”. Here, description of these configurations is omitted. In general, “Legacy LTS” or “first MIMO-LTS” in FIG. 3A may be referred to as a training signal. Here, the training signal is the signal shown in FIG. Limited to. That is, the “training signal” is a sequence corresponding to the transmission path to be estimated regardless of the number of data to be transmitted, that is, the number of series, in order to cause the wireless device 10 to be communicated to perform transmission path estimation. It corresponds to a number of MIMO-LTS. Hereinafter, “first MIMO-STS” to “fourth MIMO-STS” are collectively referred to as “MIMO-STS”, “first MIMO-LTS” to “fourth MIMO-LTS” are collectively referred to as “MIMO-LTS”, “One data” and “second data” are collectively referred to as “data”.

  FIG. 3C corresponds to a modification of FIG. As illustrated, “third MIMO-LTS” and “fourth MIMO-LTS” are arranged at timings different from “first MIMO-LTS” and “second MIMO-LTS”. In this case, “MIMO-STS” is not added to “third MIMO-LTS” and “fourth MIMO-LTS”. Since the AGC is set, the set value by the AGC can be optimized for reception of “first data” and “second data”. Note that the signals shown in FIGS. 3A to 3C may be collectively referred to as a packet signal, or a signal transmitted from one antenna 12 may be referred to as a packet signal. Here, they are used without distinction.

  FIG. 4 is a sequence diagram illustrating a communication procedure in the communication system 100. Here, an operation in which the first radio apparatus 10a acquires rate information of the second radio apparatus 10b is shown. For the sake of brevity, the operation of adaptive array signal processing is omitted. The first radio apparatus 10a transmits a rate request signal to the second radio apparatus 10b (S10). The second radio apparatus 10b transmits rate information to the first radio apparatus 10a (S12). The first radio apparatus 10a sets a data rate based on the rate information (S14). That is, the data rate is set while referring to the rate information. The first radio apparatus 10a transmits data at the set data rate (S16). The second radio apparatus 10b performs reception processing on the data (S18). The first radio apparatus 10a may acquire rate information by a method other than this.

  FIG. 5 is a sequence diagram showing another communication procedure in the communication system 100. Here, an operation in which data is transmitted by MIMO is shown. When data is transmitted from the first radio apparatus 10a to the second radio apparatus 10b, the first radio apparatus 10a has to derive a transmission weight vector in advance based on the training signal. For this purpose, the first radio apparatus 10a requests the second radio apparatus 10b to transmit a training signal (hereinafter, the request signal is referred to as a “training request signal”) (S20). The training request signal is included in “first data” and “second data” in FIG. The second radio apparatus 10b transmits a training signal to the first radio apparatus 10a according to the training request signal (S22). The first radio apparatus 10a derives a transmission weight vector based on the received training signal and sets it (S24). The first radio apparatus 10a transmits data while using the transmission weight vector (S26). The second radio apparatus 10b derives a reception weight vector for the received data and sets it (S28). Further, the second radio apparatus 10b executes a data reception process based on the reception weight vector (S30).

  FIG. 6 shows the configuration of the first radio apparatus 10a. The first radio apparatus 10a includes a first radio unit 20a, a second radio unit 20b, a fourth radio unit 20d, which are collectively referred to as a radio unit 20, and a first processing unit 22a and a second processing unit 22b, which are collectively referred to as a processing unit 22. , A fourth processing unit 22d, a first modulation / demodulation unit 24a, a second modulation / demodulation unit 24b, a fourth modulation / demodulation unit 24d, an IF unit 26, a control unit 30, and a rate information management unit 32. Further, as signals, a first time domain signal 200a, a second time domain signal 200b, a fourth time domain signal 200d, which are collectively referred to as a time domain signal 200, a first frequency domain signal 202a, which is collectively referred to as a frequency domain signal 202, and a second time domain signal 200b. A frequency domain signal 202b and a fourth frequency domain signal 202d are included. The second radio apparatus 10b has the same configuration. Also, different configurations are included depending on whether the first radio apparatus 10a or the second radio apparatus 10b is a base station apparatus or a terminal apparatus. Omitted.

  As a reception operation, the radio unit 20 performs frequency conversion on a radio frequency signal received by the antenna 12 to derive a baseband signal. The radio unit 20 outputs the baseband signal as the time domain signal 200 to the processing unit 22. In general, baseband signals are formed by in-phase and quadrature components, so they should be transmitted by two signal lines. Here, for clarity of illustration, only one signal line is used. Shall be shown. An AGC and A / D converter are also included. As a transmission operation, the radio unit 20 performs frequency conversion on the baseband signal from the processing unit 22 and derives a radio frequency signal. Here, a baseband signal from the processing unit 22 is also shown as a time domain signal 200. The radio unit 20 outputs a radio frequency signal to the antenna 12. Further, a PA (Power Amplifier) and a D / A converter are also included. The time domain signal 200 is a multicarrier signal converted into the time domain, and is a digital signal. Further, the signal processed in the radio unit 20 forms a packet signal, and the packet format is as shown in FIGS.

  As a receiving operation, the processing unit 22 converts each of the plurality of time domain signals 200 into the frequency domain, and performs adaptive array signal processing on the frequency domain signal. The processing unit 22 outputs the result of adaptive array signal processing as the frequency domain signal 202. One frequency domain signal 202 corresponds to a signal transmitted from one antenna 14 in FIG. 2, which corresponds to a signal corresponding to one transmission path. As a transmission operation, the processing unit 22 receives the frequency domain signal 202 as a frequency domain signal from the modem unit 24 and performs adaptive array signal processing on the frequency domain signal. Further, the processing unit 22 converts the signal subjected to the adaptive array signal processing into the time domain and outputs it as the time domain signal 200. It is assumed that the number of antennas 12 to be used in the transmission process is specified by the control unit 30. Here, the frequency domain signal 202, which is a frequency domain signal, includes a plurality of subcarrier components as shown in FIG. For the sake of clarity, it is assumed that the signals in the frequency domain are arranged in the order of subcarrier numbers to form a serial signal.

  FIG. 7 shows the structure of a signal in the frequency domain. In the “i” th OFDM symbol, subcarrier components are arranged in the order of subcarrier numbers “1” to “28” and subcarrier numbers “−28” to “−1”. Also, the “i−1” th OMDM symbol is arranged before the “i” th OFDM symbol, and the “i + 1” th OMDM symbol is arranged after the “i” th OFDM symbol. And In the “Legacy signal” or the like, it is assumed that the subcarrier components are arranged in the order of subcarrier numbers “1” to “26” and subcarrier numbers “−26” to “−1”.

  Returning to FIG. The modem unit 24 performs demodulation and decoding on the frequency domain signal 202 from the processing unit 22 as reception processing. Note that demodulation and decoding are performed in units of subcarriers. The modem unit 24 outputs the decoded signal to the IF unit 26. Further, the modem unit 24 performs encoding and modulation as transmission processing. The modem unit 24 outputs the modulated signal to the processing unit 22 as the frequency domain signal 202. It is assumed that the modulation scheme and coding rate are specified by the control unit 30 during the transmission process. The designation is made based on the rate information described above.

  The modem unit 24 will be described in more detail. In the transmission process, the modem unit 24 performs interleaving on the unknown signal among the legacy signals. The interleaving is a process for an unknown signal arranged in a subcarrier “48”. Further, the modem unit 24 performs interleaving on the unknown signal in the data. The interleaving is a process for the unknown signal arranged in the subcarrier “52”. That is, different rules of interleaving are performed on Legacy signals and data. Further, the modem unit 24 performs interleaving on the unknown signal in the MIMO signal. The interleaving is a process for the unknown signal arranged in the subcarrier “52”. That is, the same rule interleaving is performed on the MIMO signal and the data.

  The modem unit 24 inserts pilot signals into some subcarriers with respect to the Legacy signal and data among the packet signals shown in FIGS. On the other hand, no pilot signal is inserted into the MIMO signal. Here, the number of subcarriers corresponding to the unknown signal in the MIMO signal is greater than the number of subcarriers corresponding to the unknown signal in the Legacy signal, and the unknown signal in the MIMO signal Pilot signal insertion is performed so that the number of corresponding subcarriers is equal to the number of subcarriers corresponding to the unknown signal in the data. In order to satisfy the above conditions, the modem unit 24 inserts pilot signals into “4” subcarriers for the legacy signal and the data.

  As a reception process, the modem unit 24 receives a packet signal as shown in FIGS. The modem unit 24 extracts the legacy signal and the pilot signal inserted in the data from the packet signal in order to execute synchronous detection. The modem unit 24 performs deinterleaving on the unknown signal of the legacy signal from which the pilot signal is extracted. The deinterleaving is a process for an unknown signal arranged in a subcarrier of “48”. Also, the modem unit 24 performs deinterleaving on the data unknown signal. The deinterleaving is a process for an unknown signal arranged in a subcarrier of “52”. That is, different rules of deinterleaving are performed on the Legacy signal and the data. Further, the modem unit 24 performs deinterleaving on the unknown signal in the MIMO signal. The deinterleaving is a process for an unknown signal arranged in a subcarrier of “52”. That is, the same rule deinterleaving is performed on the MIMO signal and the data.

  The IF unit 26 combines signals from the plurality of modulation / demodulation units 24 as a reception process to form one data stream. The IF unit 26 outputs a data stream. In addition, the IF unit 26 inputs one data stream as transmission processing and separates it. Further, the separated data is output to a plurality of modems 24.

  A case where a request signal is transmitted with the above configuration will be described. As illustrated in FIGS. 3A to 3C, the processing unit 22 transmits data corresponding to each antenna 12 from at least one of the plurality of antennas 12. When the number of antennas 12 to be used is “2”, this corresponds to “first data” and “second data” in FIGS. It is assumed that the number of antennas 12 to be used for data transmission is instructed by the control unit 30. Further, the processing unit 22 adds a signal other than data such as “Legacy STS” as shown in FIG. If the number of antennas 12 to be used for data transmission is “4”, “third data” and “fourth data” not shown in FIGS. 3A to 3C are added. . Such data is transmitted to the second radio apparatus 10b corresponding to the variable data rate. The control unit 30 generates a request signal for causing the second radio apparatus 10b to provide rate information in the second radio apparatus 10b. Further, the control unit 30 outputs the generated request signal to the modem unit 24. Here, the request signal is assigned to “first data” and “second data” in FIGS.

  Corresponding to the above description, a case where a request signal and a training signal are received will be described. The control unit 30 generates rate information based on the received training signal. The generation method of rate information may be arbitrary. For example, the rate information may be generated by measuring the signal strength of the signal received by the radio unit 20 and comparing the measured signal strength with a threshold value. Alternatively, rate information may be generated based on the reception weight vector derived by the processing unit 22. Further, the rate information may be generated based on the result demodulated by the modem unit 24. The determined rate information is transmitted via the modem unit 24, the processing unit 22, and the radio unit 20, and is held in the rate information management unit 32. The rate information management unit 32 also holds rate information in the wireless device 10 that is symmetrical to communication.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 8 shows a configuration of the first processing unit 22a. The first processing unit 22a includes an FFT (Fast Fourier Transform) unit 40, a synthesis unit 42, a reference signal generation unit 44, a reception weight vector calculation unit 54, a separation unit 46, a transmission weight vector calculation unit 52, an IFFT unit 48, and a preamble addition Part 50 is included. The combining unit 42 includes a first multiplying unit 56 a, a second multiplying unit 56 b, a fourth multiplying unit 56 d, and an adding unit 60 that are collectively referred to as the multiplying unit 56. The separation unit 46 includes a first multiplication unit 58a, a second multiplication unit 58b, and a fourth multiplication unit 58d, which are collectively referred to as a multiplication unit 58.

  The FFT unit 40 receives a plurality of time domain signals 200 and performs a Fourier transform on each of them to derive a frequency domain signal. As described above, in a single frequency domain signal, signals corresponding to subcarriers are serially arranged in the order of subcarrier numbers.

  Multiplier 56 weights the frequency domain signal with the received weight vector from received weight vector calculator 54, and adder 60 adds the output of multiplier 56. Here, since the signals in the frequency domain are arranged in the order of the subcarrier numbers, the reception weight vectors from the reception weight vector calculation unit 54 are also arranged so as to correspond thereto. That is, one multiplication unit 56 sequentially receives reception weight vectors arranged in the order of subcarrier numbers. Therefore, the addition unit 60 adds the multiplication results in units of subcarriers. As a result, the added signals are also serially arranged in the order of subcarrier numbers as shown in FIG. The added signal is the frequency domain signal 202 described above.

  Also in the following description, when the signal to be processed corresponds to the frequency domain, the processing is basically executed in units of subcarriers. Here, in order to simplify the description, the processing in one subcarrier will be described. Therefore, processing for a plurality of subcarriers can be handled by executing processing on one subcarrier in parallel or serially.

  The reference signal generation unit 44 stores the “Legacy STS”, “Legacy LTS”, “Legacy STS”, “Ligacy STS”, “Legacy STS”, “Ligacy STS”, “Legacy STS”, “Legacy STS”, “Last STY”, “STS” and “first MIMO-LTS” are output as reference signals. In addition to these periods, the frequency domain signal 202 is determined based on a predetermined threshold value, and the result is output as a reference signal. The determination may be a soft determination instead of a hard determination.

  The reception weight vector calculation unit 54 derives a reception weight vector based on the frequency domain signal from the FFT unit 40, the frequency domain signal 202, and the reference signal. The method for deriving the reception weight vector may be any method, one of which is the derivation by the LMS (Least Mean Square) algorithm. Further, the reception weight vector may be derived by correlation processing. In this case, the frequency domain signal and the reference signal are input not only from the first processing unit 22a but also from the second processing unit 22b and the like through a signal line (not shown). The frequency domain signal in the first processing unit 22a is denoted by x1 (t), the frequency domain signal in the second processing unit 22b is denoted by x2 (t), the reference signal in the first processing unit 22a is denoted by S1 (t), the second If the reference signal in the processing unit 22b is expressed as S2 (t), x1 (t) and x2 (t) are expressed as follows.

ここで、雑音は無視する。第１の相関行列Ｒ１は、Ｅをアンサンブル平均として、次のように示される。

参照信号間の第２の相関行列Ｒ２は、次のように計算される。

Here, noise is ignored. The first correlation matrix R1 is expressed as follows, where E is an ensemble average.

The second correlation matrix R2 between the reference signals is calculated as follows.

最終的に、第２の相関行列Ｒ２の逆行列と第１の相関行列Ｒ１を乗算することによって、受信応答ベクトルが導出される。

さらに、受信ウエイトベクトル計算部５４は、受信応答ベクトルから受信ウエイトベクトルを計算する。

Finally, the reception response vector is derived by multiplying the inverse matrix of the second correlation matrix R2 by the first correlation matrix R1.

Further, the reception weight vector calculation unit 54 calculates a reception weight vector from the reception response vector.

  The transmission weight vector calculation unit 52 estimates a transmission weight vector necessary for weighting the frequency domain signal 202 from the reception weight vector. The method for estimating the transmission weight vector is arbitrary, but as the simplest method, the reception weight vector may be used as it is. Alternatively, the reception weight vector may be corrected by a conventional technique in consideration of the Doppler frequency fluctuation of the propagation environment caused by the time difference between the reception process and the transmission process. Here, it is assumed that the reception weight vector is used as it is as the transmission weight vector.

  Multiplier 58 weights frequency domain signal 202 with the transmission weight vector and outputs the result to IFFT unit 48. The IFFT unit 48 performs inverse Fourier transform on the signal from the multiplication unit 58 to convert it into a time domain signal. As shown in FIGS. 3A to 3C, the preamble adding unit 50 adds a preamble to the head portion of the packet signal. Here, “Legacy STS”, “Legacy LTS”, “First MIMO-STS”, and “First MIMO-LTS” are added. The preamble adding unit 50 outputs the signal with the preamble added as the time domain signal 200. The preamble adding unit 50 may be provided before the multiplication unit 58. That is, a preamble may be added in the frequency domain. Note that the above operation is controlled by the control unit 30 in FIG. In FIG. 8, the first time domain signal 200a and the like are shown in two places. These are signals in one direction, and these correspond to the first time domain signal 200a and the like which are bidirectional signals in FIG.

  FIG. 9 shows the configuration of the first modem unit 24a. The first modulation / demodulation unit 24a includes a synchronous detection unit 70, a first deinterleave unit 72, a second deinterleave unit 74, a decoding unit 76, a pilot insertion unit 78, a mapping unit 80, a first interleave unit 82, and a second interleave unit 84. The encoding unit 86 is included.

  The encoding unit 86 performs encoding on the Legacy signal, the MIMO signal, and the data portion of FIGS. As described above, the encoding rate in encoding is fixed for the Legacy signal and the MIMO signal, but is variable for the data. The first interleaving unit 82 performs interleaving on the unknown signal of the Legacy signal. That is, interleaving is performed on an unknown signal to be arranged on the “48” subcarrier. The rules for interleaving may be the same as those of a known technique, for example, the standards of IEEE802.11a and g, and will not be described. The second interleaving unit 84 performs interleaving on the MIMO signal and the data unknown signal. That is, interleaving is performed on the unknown signal arranged in the subcarrier “52”. The number of subcarriers to be interleaved by second interleaving section 84 is larger than the number of subcarriers to be interleaved by first interleaving section 82.

  The mapping unit 80 maps the output signal from the first interleave unit 82 or the output signal from the second interleave unit 84. As described above, the mapping unit 80 executes mapping corresponding to BPSK, QPSK, 16QAM, and the like. Pilot insertion section 78 inserts pilot signals into subcarriers with subcarrier numbers “-21”, “−7”, “7”, and “21”. The pilot signal is inserted into the legacy signal and data as described above.

  The synchronous detection unit 70 performs synchronous detection on the frequency domain signal 202. At this time, the legacy signal and the pilot signal inserted into the data are extracted from the packet signal. The first deinterleaving unit 72 performs deinterleaving on the unknown signal of the Legacy signal. That is, deinterleaving is performed on an unknown signal to be placed on the “48” subcarrier. The second deinterleaving unit 74 performs deinterleaving on the MIMO signal and the data unknown signal. That is, deinterleaving is performed on the unknown signal arranged on the subcarrier “52”. The number of subcarriers to be deinterleaved by the second deinterleaver 74 is larger than the number of subcarriers to be deinterleaved by the first deinterleaver 72. The decoding unit 76 decodes the signal from the first deinterleaving unit 72 or the signal from the second deinterleaving unit 74. For example, the decoding unit 76 is configured by a Viterbi decoder.

  The operation of the communication system 100 configured as above will be described. As a transmission operation, the encoding unit 86 encodes a non-known signal of a legacy signal and a MIMO signal. In addition, the encoding unit 86 encodes a data unknown signal. The coding rate of the data for the unknown signal may be different from the coding rate of the legacy signal for the unknown signal and the MIMO signal. The first interleaving unit 82 performs interleaving on the unknown signal of the Legacy signal. The second interleaving unit 84 performs interleaving on the MIMO signal and the data unknown signal. The pilot insertion unit 78 inserts a pilot signal into the legacy signal and data. The multiplier 58 weights the data with the transmission weight vector from the transmission weight vector calculator 52, and the IFFT unit 48 executes IFFT on the legacy signal, MIMO signal, and data. The preamble adding unit 50 adds Legacy STS and the like.

  As a reception operation, the FFT unit 40 performs FFT. The synthesis unit 42 performs array synthesis. The synchronous detection unit 70 performs synchronous detection while extracting a legacy signal and a pilot signal included in the data. The first deinterleaving unit 72 performs deinterleaving on the unknown signal of the Legacy signal. The second deinterleaving unit 74 performs deinterleaving on the MIMO signal and the data unknown signal. The decoding unit 76 decodes the unknown signal and the MIMO signal of the Legacy signal. Further, the decoding unit 76 decodes an unknown signal of data.

  Here, a modification of the present embodiment will be described. The modification relates to a transmission device having a transmission function in the first wireless device and the second wireless device. Further, the same packet signal as in the embodiment is transmitted. The transmitting apparatus transmits a plurality of series of packet signals according to the number of the plurality of antennas, and arranges the plurality of MIMO-STSs in the plurality of series of packet signals. Further, the transmission apparatus arranges a plurality of MIMO-LTSs in a plurality of packet signals following the plurality of MIMO-STSs. Furthermore, the transmission apparatus arranges data in a part of a plurality of series of packet signals. The transmission device multiplies the data by a steering matrix to increase the data to the number of a plurality of sequences. The transmission device also multiplies the steering matrix for MIMO-LTS. However, the transmitter does not multiply the MIMO-STS by the steering matrix. Hereinafter, a plurality of series of packet signals multiplied by the steering matrix are also referred to as “a plurality of series of packet signals” without being distinguished from the above.

  Here, MIMO-STS has a predetermined period. Specifically, a guard interval is added to a signal having a period of 1.6 μs. Note that the steering matrix described above includes a component that causes a cyclic time shift to be performed for each series. The cyclic time shift is called CDD (Cyclic Delay Diversity), and here, a cyclic time shift is performed with respect to the period of the pattern included in the MIMO-LTS. Similar processing is performed on the data. In addition, the time shift amount differs in units of a plurality of series of packet signals, but at least one of these time shift amounts is defined more than the period of MIMO-STS. As described above, the transmission apparatus deforms a plurality of series of packet signals and transmits the plurality of modified packet signals from the plurality of antennas.

  The problem corresponding to the above-described modification may be indicated as follows. That is, it is desired to execute transmission in a packet format that improves the accuracy of channel estimation in the wireless device to be communicated. In addition, it is desired to execute transmission in a packet format that improves the accuracy of rate information in the wireless device to be communicated. Further, even when such a training signal is transmitted, it is desired to transmit the data in a packet format that suppresses deterioration of the data communication quality.

  FIG. 10 shows a configuration of a transmission apparatus 300 according to a modification example of the present invention. The transmission apparatus 300 includes an error correction unit 310, an interleaving unit 312, a modulation unit 314, a preamble adding unit 316, a spatial dispersion unit 318, a first radio unit 20a, a second radio unit 20b, and a third radio unit collectively referred to as a radio unit 20. Unit 20c, fourth radio unit 20d, first antenna 12a, second antenna 12b, third antenna 12c, and fourth antenna 12d, collectively referred to as antenna 12. Here, the transmission apparatus 300 in FIG. 10 corresponds to a part of the first radio apparatus 10a in FIG.

  The error correction unit 310 performs data encoding for error correction. The error correction unit 310 corresponds to the encoding unit 86 in FIG. Here, it is assumed that convolutional encoding is performed, and the encoding rate is selected from predetermined values. The interleave unit 312 interleaves the convolutionally encoded data. Further, interleaving section 312 outputs the data after separating it into a plurality of sequences. Here, it is separated into two series. The two series of data can be said to be independent of each other. Further, the interleave unit 312 includes the first interleave unit 82 and the second interleave unit 84 shown in FIG.

  Modulation section 314 performs modulation on each of the two series of data. Modulation section 314 corresponds to mapping section 80 and pilot insertion section 78 in FIG. The preamble adding unit 316 adds a preamble to the modulated data. Therefore, the preamble adding unit 316 stores MIMO-STS, MIMO-LTS, etc. as a preamble. Preamble adding section 316 generates a plurality of sequence packet signals including MIMO-STS and MIMO-LTS respectively arranged in the plurality of sequences, and data arranged in at least one of the plurality of sequences. As described above, data is formed by two series. Here, since the plurality of sequences are “4”, MIMO-STS and MIMO-LTS are respectively arranged in the four sequences of packet signals, and data is arranged in two of the four sequences of packet signals. . As a result, the preamble adding unit 316 outputs four series of packet signals.

  Here, the details of the MIMO-STS are omitted, but for example, at least an STS corresponding to one of a plurality of series of packet signals is compared to an STS corresponding to another series of packets. It may be defined that at least a part uses different subcarriers. In addition, the STS may be defined so that the number of subcarriers to be used for each STS is equal and different subcarriers are used. Further, as described above, each of a plurality of series of packet signals uses a plurality of subcarriers, and the MIMO-LTS arranged in the plurality of series of packet signals is different for each series. Use a carrier. That is, tone interleaving is performed.

  The spatial dispersion unit 318 increases the MIMO-LTS multiplied by the steering matrix and the number of the plurality of sequences by multiplying the MIMO matrix and the data by the steering matrix among the packet signals of the plurality of sequences, respectively. Generated data. Here, the spatial distribution unit 318 extends the order of the input data to the number of a plurality of sequences before performing multiplication. The number of input data is “2”, which is represented by “Nin” here. Therefore, the input data is indicated by a vector “Nin × 1”. Further, the number of the plurality of series is “4”, and is represented by “Nout” here. The spatial distribution unit 318 extends the order of the input data from Nin to Nout. That is, the vector “Nin × 1” is expanded to the vector “Nout × 1”. At that time, “0” is inserted into the components from the Nin + 1 line to the Nout line.

ステアリング行列は、「Ｎｏｕｔ×Ｎｏｕｔ」の行列である。また、Ｗは、直交行列であり、「Ｎｏｕｔ×Ｎｏｕｔ」の行列である。直交行列の一例は、ウォルシュ行列である。ここで、ｌは、サブキャリア番号を示しており、ステアリング行列による乗算は、サブキャリアを単位にして実行される。さらに、Ｃは、以下のように示され、ＣＤＤのために使用される。

The steering matrix S is shown as follows.

The steering matrix is a “Nout × Nout” matrix. W is an orthogonal matrix, which is a “Nout × Nout” matrix. An example of an orthogonal matrix is a Walsh matrix. Here, l indicates a subcarrier number, and multiplication by the steering matrix is executed in units of subcarriers. In addition, C is shown as follows and is used for CDD.

  Here, δ represents the shift amount. That is, the spatial dispersion unit 318 performs a cyclic time shift in the MIMO-LTS multiplied by the orthogonal matrix by the shift amount corresponding to each of the plurality of sequences, while performing the number of the plurality of sequences. A cyclic time shift within the data increased up to is executed for each series. The structure of MIMO-LTS has the same structure as Legacy LTS which is LTS in the IEEE802.11a standard. The shift amount is set to a different value for each series. At that time, at least one of the shift amounts corresponding to each of the plurality of sequences is set to be equal to or longer than a predetermined period possessed by the MIMO-STS. Since the period of the MIMO-STS is 1.6 μs, at least one of the shift amounts is set to 1.6 μs, for example. In such a case, even if a time shift is performed on the MIMO-STS, this is equivalent to no shift. Therefore, here, no time shift is performed on the MIMO-STS. As a result of the above processing, the spatial dispersion unit 318 transforms a plurality of series of packet signals.

  The same number of radio units 20 as the antennas 12 are provided. The radio unit 20 transmits a plurality of modified packet signals. At that time, the radio unit 20 transmits a plurality of modified packet signals corresponding to the plurality of antennas 12. The radio unit 20 includes an IFFT unit, a GI unit, an orthogonal modulation unit, a frequency conversion unit, and an amplification unit (not shown). The IFFT unit performs IFFT and converts a frequency domain signal using a plurality of subcarrier carriers into a time domain. The GI unit adds a guard interval to the time domain data. The quadrature modulation unit performs quadrature modulation. The frequency converter converts the orthogonally modulated signal into a radio frequency signal. The amplifying unit is a power amplifier that amplifies a radio frequency signal. In addition, the space dispersion | distribution part 318 may be provided in the back | latter stage of the IFFT part which is not shown in figure.

  FIGS. 11A to 11B show packet formats of packet signals generated in the transmission apparatus 300. FIG. Here, the training signal will be specifically described here, but the same processing may be applied to other packet signals. FIG. 11A shows a packet format in a plurality of series of packet signals output from the preamble adding unit 316. Since FIG. 11A is equivalent to FIG. 3B, the description is omitted. Here, “4” MIMO-STS and “4” MIMO-LTS are added to each of a plurality of “4” sequence packet signals. On the other hand, data of “2” series, which is at least one of a plurality of series, is added as “first data” and “second data”. FIG. 11B shows a plurality of series of packet signals transformed by the spatial dispersion unit 318. MIMO-STS is the same as that shown in FIG. The MIMO-LTS in FIG. 11A is “MIMO-LTS ′” as a result of the multiplication of the steering matrix. In FIG. 11 (b), this is indicated as “first MIMO-LTS ′” to “fourth MIMO-LTS ′”. “First data” and “second data” in FIG. 11A are four series of data as a result of steering matrix multiplication. In FIG. 11B, this is shown as “first data” to “fourth data”.

  Further, another embodiment will be described. In the modification, the signal point arrangement of the Legacy signal and the MIMO signal is different. FIGS. 12A to 12D show constellations of signals included in the burst format of FIGS. 3A to 3C. FIG. 12 (a) shows a constellation for the MIMO signal. As shown in the figure, the modulation method of the MIMO signal corresponds to BPSK, and the signal point is defined so that the orthogonal component is “+1” or “−1”. That is, the in-phase component is defined to be “0”. FIG. 12B shows a constellation for Legacy signals and data. As shown in the figure, the constellation for the legacy signal and data also corresponds to BPSK, but the in-phase component is defined to be “+1” or “−1”, and the quadrature component is “0”. It is prescribed. Note that the modulation method of data is appropriately switched, and QPSK, 16QAM, and 64QAM may be used in addition to BPSK. FIG. 12C shows a case where the constellation is for data and the modulation method is QPSK. FIG. 12D shows a case where the constellation is for data and the modulation method is 16QAM.

  The mapping unit 80 in FIG. 9 and the modulation unit 314 in FIG. 10 execute mapping as described above. Correspondingly, a determination unit (not shown) is added to the synchronous detection unit 70 of FIG. The determination unit determines whether a MIMO signal is arranged after the Legacy signal. Here, as described above, the determination uses a difference in arrangement of signal points between the Legacy signal and the MIMO signal. That is, the Legacy signal and the MIMO signal have different in-phase component and quadrature component values with respect to the signal point. By detecting these differences, the determination unit can distinguish between the Legacy signal and the MIMO signal.

  According to the embodiment of the present invention, in the MIMO signal, the pilot signal is set such that the number of subcarriers corresponding to the unknown signal is larger than the number of subcarriers corresponding to the unknown signal among the legacy signals. Since it is inserted, the transmission efficiency in the MIMO signal can be improved over the transmission efficiency in the Legacy signal. Moreover, even if the number of subcarriers used for the Legacy signal and the MIMO signal is the same, the transmission efficiency of the MIMO signal can be increased. In addition, since the MIMO preamble is arranged after the MIMO signal, it is possible to suppress deterioration in transmission quality. Also, since the pilot signal is inserted in the MIMO signal so that the number of subcarriers corresponding to the unknown signal in the data is equal to the number of subcarriers corresponding to the unknown signal in the data, it is larger than the MIMO signal. The unknown signal can be transmitted by the same number of subcarriers as the number of subcarriers used, and transmission efficiency can be improved. In addition, the same interleave unit can be used for the MIMO signal and the data. Further, since the same interleave unit is used, an increase in circuit scale can be suppressed.

  Even if the number of data sequences is smaller than the number of MIMO-LTS sequences, multiplication by an orthogonal matrix and cyclic time shift processing are executed, so the number of data sequences is the number of MIMO-LTS sequences. Can match. Also, since MIMO-LTS performs the same processing as that of the data sequence, the wireless device to be communicated can use MIMO-LTS when receiving data. Also, since MIMO-STS does not perform the same processing as that of the data series, the amount of time shift in CDD can be increased, and the reception characteristics in the radio apparatus to be communicated can be improved. Moreover, since MIMO-LTS is transmitted from all antennas, the receiving side can estimate an assumed transmission path. Further, even if the number of data series is not equal to the number of antennas, signals can be transmitted uniformly from all antennas by executing processing on the data using the Walsh matrix and CDD. Further, the power of data can be matched with MIMO-LTS.

  In addition, since processing by Walsh matrix and CDD is also performed for MIMO-LTS, the transmission path estimated by MIMO-LTS can be used as it is for data reception on the receiving side. Also, if CDD is executed with a sufficiently large shift amount for the MIMO-LTS and the data, the power difference between the MIMO-LTS and the data becomes very small, so that the accuracy of AGC setting on the receiving side can be improved. In addition, since the MIMO-STS cannot be time-shifted with a large shift amount, in this case, the MIMO-STS and the MIMO-LTS can be combined with each other by associating the MIMO-STS with all the antennas. Also, the power of MIMO-STS and MIMO-LTS can be combined without performing CDD processing for MIMO-STS. Also, since MIMO-LTS is tone interleaved, transmission power can be maintained even when MIMO-LTS is transmitted from all antennas by processing using Walsh matrix and CDD. Also, when processing by Walsh matrix and CDD is not performed, when transmitting two series of data with three antennas, each power in the packet signal is “three STS” = “three LTS”> “two” “Data”, but when the MIMO-LTS and data are processed by the Walsh matrix and CDD, “3 STS” = “3 LTS” = “3 data” can be set.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the second interleaving unit 84 performs interleaving on the MIMO signal and the data unknown signal, and the second deinterleaving unit 74 performs interleaving on the MIMO signal and the data unknown signal. is doing. However, the present invention is not limited to this. For example, the first interleaving unit 82 performs interleaving on the legacy signal and the MIMO signal and the MIMO signal, and the first deinterleaving unit 72 performs the legacy signal and the unknown signal on the MIMO signal. Interleaving may be performed. More specifically, the first interleaving unit 82 performs interleaving on the portion of the MIMO signal corresponding to the unknown signal in the legacy signal. Here, “the portion corresponding to the unknown signal in the legacy signal in the MIMO signal” indicates “48” subcarriers in which the unknown signal in the legacy signal is arranged.

  In addition, the first interleaving unit 82 performs allocation to a subcarrier that should correspond to the pilot signal of the Legacy signal for a portion of the MIMO signal that does not correspond to the unknown signal in the Legacy signal. . In addition, the first deinterleaving unit 72 performs deinterleaving on the portion of the MIMO signal corresponding to the unknown signal in the legacy signal. In addition, the first deinterleaving unit 72 performs synthesis of a portion of the MIMO signal that does not correspond to the unknown signal in the legacy signal with a portion that has been deinterleaved. According to the modified example, since the same interleave part and deinterleave part can be used for continuous parts of the packet signal, such as Legacy signal and MIMO signal, switching in the middle of the signal can be omitted. That is, the interleaving unit and the deinterleaving unit already provided for interleaving and deinterleaving for the MIMO signal may be used.

  In the embodiment of the present invention, the MIMO signal may be arranged in a plurality of symbols or may be arranged in one symbol. At that time, the modem unit 24 may map the MIMO signal in all the subcarriers as shown in FIG. According to this modification, the arrangement of the MIMO signal can be detected by the signal point arrangement regardless of the number of symbols of the MIMO signal.

  In the embodiment of the present invention, the pilot signal is not inserted into the MIMO signal. However, the present invention is not limited to this. For example, when a plurality of symbols are arranged as a MIMO signal, the pilot signal may not be inserted into the rear symbol. That is, a pilot signal may be inserted into a front symbol among a plurality of symbols. For example, when a plurality of symbols are “2” symbols, a pilot is inserted in the preceding symbol, and a pilot is not inserted in the following symbol. When the number of symbols is “2” or more, the number of symbols corresponding to “front part” and “rear part” may be determined as appropriate. Note that the pilot signal may be inserted into the same subcarrier as the legacy signal. Moreover, the same processing as a legacy symbol should just be performed to the front symbol among MIMO signals. According to this modification, transmission quality can be improved.

  Further, pilot insertion section 78 may insert a pilot signal different from the pilot signal to be inserted into the Legacy signal in at least the front symbol among the MIMO signals arranged in the plurality of symbols. For example, the pilot signals may be set to have different phases. For example, the pilot signal of the MIMO signal and the pilot signal of the Legacy signal may have the relationship shown in FIGS. 12A and 12B, or the same signal point arrangement but only the phase is different by 180 degrees. It may be set. According to this modification, it is possible to notify whether the signal is a MIMO signal according to the value of the pilot signal. That is, it is only necessary to improve the transmission efficiency with the MIMO signal. Also, the pilot signal of the MIMO signal and the pilot signal of the Legacy signal may have the same signal point arrangement, and the unknown signal of the MIMO signal and the unknown signal of the Legacy signal may have different signal point arrangements. For example, the unknown signal of the MIMO signal and the unknown signal of the Legacy signal may have the relationship shown in FIGS. In this case, even if the pilot signal of the MIMO signal and the pilot signal of the Legacy signal have the same signal point arrangement, the MIMO signal can be detected. Furthermore, the pilot signal of the MIMO signal and the pilot signal of the Legacy signal have the same signal point arrangement, but are set so that only the phase is different by 180 degrees, and the unknown signal of the MIMO signal and the unknown signal of the Legacy signal are shown in FIG. It may have a relationship of 12 (a)-(b). In this case, the MIMO signal detection accuracy is improved.

  In the embodiment of the present invention, Legacy STS or the like is transmitted from one antenna 12. However, the present invention is not limited to this, and for example, Legacy STS or the like may be transmitted from a plurality of antennas 12 by executing CDD for Legacy STS or the like. According to this modification, the power difference in the entire packet signal can be reduced.

  In the embodiment of the present invention, the first radio apparatus 10a makes the number of antennas 12 to be used when transmitting a training signal equal to the number of antennas 12 to be used when receiving a training signal. Is controlling. However, the present invention is not limited to this, and control may be performed so that they are different, for example. That is, the processing unit 22 receives a training signal for reception from the second radio apparatus 10b by the plurality of antennas 12, and the selection unit 28 transmits at least one of the plurality of antennas 12 to which the training signal should be transmitted. The antenna 12 is selected. At this time, the selection unit 28 may derive radio quality corresponding to each of the plurality of antennas 12 based on the received training signal for reception, and preferentially select the antennas 12 having good radio quality. . According to this modification, the number of transmitting antennas 12 and the number of receiving antennas 12 can be set independently.

It is a figure which shows the spectrum of the multicarrier signal which concerns on the Example of this invention. It is a figure which shows the structure of the communication system which concerns on the Example of this invention. FIGS. 3A to 3C are diagrams showing a packet format configuration in the communication system of FIG. It is a sequence diagram which shows the communication procedure in the communication system of FIG. It is a sequence diagram which shows another communication procedure in the communication system of FIG. It is a figure which shows the structure of the 1st radio | wireless apparatus of FIG. It is a figure which shows the structure of the signal of the frequency domain in FIG. It is a figure which shows the structure of the 1st process part of FIG. It is a figure which shows the structure of the 1st modulation / demodulation part of FIG. It is a figure which shows the structure of the transmitter which concerns on the modification of this invention. FIGS. 11A and 11B are diagrams illustrating packet formats of packet signals generated in the transmission apparatus of FIG. FIGS. 12A to 12D are diagrams showing constellations of signals included in the burst formats of FIGS. 3A to 3C.

Explanation of symbols

  10 radio equipment, 12 antennas, 14 antennas, 20 radio units, 22 processing units, 24 modulation / demodulation units, 26 IF units, 30 control units, 32 rate information management units, 70 synchronous detection units, 72 first deinterleave units, 74 first units 2 deinterleaving section, 76 decoding section, 78 pilot insertion section, 80 mapping section, 82 first interleaving section, 84 second interleaving section, 86 coding section, 100 communication system.

Claims (14)

A number of subcarriers different from the number of subcarriers in the second control signal are used behind the first preamble, the first control signal, and the second control signal, which should use a plurality of subcarriers, respectively. Among the 2 preambles and data, and the second preamble to be controlled by the second control signal and the packet signal in which the data is arranged, at least the first control signal and data are known signals in some subcarriers An insertion portion for inserting,
A generation unit that generates a packet signal by including the first control signal and data in which the known signal is inserted by the insertion unit;
The insertion unit includes the first control unit such that the number of subcarriers corresponding to the unknown signal in the second control signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. A transmission apparatus, wherein a known signal is inserted into some subcarriers of a control signal. Among the packet signals generated by the generation unit, the number of subcarriers used in the second preamble and data is the number of subcarriers used in the first preamble, the first control signal, and the second control signal. Is specified to be larger than
The insertion unit may include a part of the data so that the number of subcarriers corresponding to the unknown signal in the second control signal is equal to the number of subcarriers corresponding to the unknown signal in the data. The transmission apparatus according to claim 1, wherein a known signal is inserted into each subcarrier. An interleaving unit that performs interleaving on the unknown signal among the first control signals;
The interleaving unit performs interleaving on a portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and the unknown signal in the second control signal. 2. The arrangement of subcarriers that should correspond to known signals in the first control signal is performed on portions of the first control signal that do not correspond to unknown signals. The transmitting device according to 1. An interleaving unit that performs interleaving on the unknown signal among the data,
The transmission apparatus according to claim 2, wherein the interleaving unit performs interleaving on the unknown signal in the second control signal.   When generating the packet signal, the generation unit arranges the second control signal in a plurality of symbols, and the insertion unit arranges the second control signal in a plurality of symbols as an unknown signal in the second control signal. The transmission apparatus according to claim 1 or 2, wherein among the two control signals, at least a non-known signal in a rear symbol is a target of processing.   When generating the packet signal, the generating unit arranges the second control signal in a plurality of symbols, and the interleaving unit outputs a second signal arranged in the plurality of symbols as an unknown signal in the second control signal. 5. The transmission apparatus according to claim 3, wherein a non-known signal in at least a rear symbol among the control signals is a processing target.   The insertion unit inserts a known signal different from a known signal to be inserted into the first control signal in a front symbol among the second control signals arranged in a plurality of symbols. The transmission device according to any one of 5 and 6. A number of subcarriers different from the number of subcarriers in the second control signal are used behind the first preamble, the first control signal, and the second control signal, which should use a plurality of subcarriers, respectively. A receiver for receiving a packet signal for arranging the second preamble and data, which are two preambles and data and controlled by the second control signal;
An extraction unit that extracts at least a first control signal and a known signal inserted into data from the packet signals received by the reception unit;
A deinterleaving unit that performs deinterleaving on the unknown signal of the first control signal from which the known signal is extracted by the extraction unit;
In the second control signal in the packet received by the receiving unit, the number of subcarriers corresponding to the unknown signal is larger than the number of subcarriers corresponding to the unknown signal in the first control signal. Stipulated in
The deinterleaving unit performs deinterleaving on a portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and is unknown in the second control signal. A receiving apparatus, comprising: combining a portion of a signal that does not correspond to an unknown signal in the first control signal with a portion that has been deinterleaved. A number of subcarriers to be used is greater than the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal to be used respectively. A receiver for receiving a packet signal for arranging the second preamble and data, which are two preambles and data and controlled by the second control signal;
An extraction unit that extracts at least a first control signal and a known signal inserted in data from the packet signal received by the reception unit;
A deinterleaving unit that performs deinterleaving on the non-known signal of the data from which the known signal is extracted by the extraction unit;
In the second control signal in the packet received by the receiving unit, the number of subcarriers corresponding to the unknown signal is defined to be equal to the number of subcarriers corresponding to the unknown signal in the data. And
The receiving apparatus according to claim 1, wherein the deinterleaving unit performs deinterleaving on the unknown signal in the second control signal. A number of subcarriers different from the number of subcarriers in the second control signal are used behind the first preamble, the first control signal, and the second control signal, which should use a plurality of subcarriers, respectively. Among the 2 preambles and data, and the second preamble to be controlled by the second control signal and the packet signal in which the data is arranged, at least the first control signal and data are known signals in some subcarriers A transmission method for generating a packet signal by inserting
The number of subcarriers corresponding to the unknown signal among the second control signals arranged in the plurality of symbols is larger than the number of subcarriers corresponding to the unknown signal among the first control signals. A transmission method characterized by inserting a known signal into some subcarriers of the first control signal. A number of subcarriers different from the number of subcarriers in the second control signal are used behind the first preamble, the first control signal, and the second control signal, which should use a plurality of subcarriers, respectively. Receiving a packet signal for arranging two preambles, data and a second preamble controlled by the second control signal;
Extracting at least a first control signal and a known signal inserted in data from the received packet signal, and performing deinterleaving on the unknown signal of the first control signal from which the known signal is extracted. Prepared,
In the second control signal of the packets received in the receiving step, the number of subcarriers corresponding to the unknown signal is larger than the number of subcarriers corresponding to the unknown signal of the first control signal. Is defined as
The step of executing deinterleaving performs deinterleaving on a portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and uses the second control signal. A receiving method, comprising: combining a portion that does not correspond to the unknown signal in the first control signal with a portion that has undergone deinterleaving. A number of subcarriers to be used is greater than the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal to be used respectively. Receiving a packet signal for arranging two preambles, data and a second preamble controlled by the second control signal;
A step of extracting at least a first control signal and a known signal inserted into data from the received packet signal, and performing deinterleaving on the unknown signal of the data from which the known signal is extracted,
In the second control signal of the packets received in the receiving step, the number of subcarriers corresponding to the unknown signal is defined to be equal to the number of subcarriers corresponding to the unknown signal of data. And
The step of executing deinterleaving performs deinterleaving on an unknown signal in the second control signal. A number of subcarriers different from the number of subcarriers in the second control signal are used behind the first preamble, the first control signal, and the second control signal, which should use a plurality of subcarriers, respectively. While performing interleaving on the unknown signal of the first control signal among the two preambles and data, and the second preamble to be controlled by the second control signal and the packet signal in which the data is arranged, at least A transmitter that generates a packet signal by inserting a known signal into some subcarriers with respect to the first control signal and data;
A receiving device that extracts at least a first control signal and a known signal inserted in data from the received packet signal, and performs deinterleaving on the unknown signal of the first control signal from which the known signal is extracted; With
The transmitting apparatus includes a first control unit such that a number of subcarriers corresponding to an unknown signal in the second control signal is larger than a number of subcarriers corresponding to an unknown signal in the first control signal. Interleaving is performed on the portion corresponding to the unknown signal in the first control signal among the unknown signal in the second control signal and the means for inserting the known signal into some subcarriers in the control signal While executing, a subcarrier that should correspond to a known signal of the first control signal for a portion of the unknown signal of the second control signal that does not correspond to the unknown signal of the first control signal Means for performing placement on
The receiving apparatus performs deinterleaving on a portion of the unknown signal in the second control signal corresponding to the unknown signal in the first control signal, and the unknown signal in the second control signal. Among these, a communication system is characterized in that a portion that does not correspond to an unknown signal in the first control signal is combined with a portion that has been deinterleaved. A number of subcarriers to be used is greater than the number of subcarriers in the second control signal behind the first preamble, the first control signal, and the second control signal to be used respectively. 2 preambles and data, and a second preamble to be controlled by the second control signal. Among packet signals for arranging data, at least a first control is performed while interleaving is performed on an unknown signal of the data. A transmitter that generates a packet signal by inserting a known signal into some subcarriers for the signal and data; and
A reception device that extracts at least a first control signal and a known signal inserted into data from the received packet signal, and performs deinterleaving on the unknown signal of the data from which the known signal is extracted;
The transmitting apparatus includes means for inserting a known signal into some subcarriers of data so as to be equal to the number of subcarriers corresponding to an unknown signal in the second control signal, and a second control signal Means for performing interleaving on the unknown signal at
The communication apparatus according to claim 1, wherein the receiving apparatus performs deinterleaving on the unknown signal in the second control signal.

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