JP4597042B2 - TRANSMISSION METHOD AND RECEPTION METHOD, AND BASE STATION DEVICE, TERMINAL DEVICE, AND COMMUNICATION SYSTEM USING THEM - Google Patents

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 packet signals formed in a plurality of streams, and a base station apparatus, a terminal 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 standardization 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. There is a MIMO (Multiple Input Multiple Output) system as a technique for increasing the data rate by using such adaptive array antenna technology. In the MIMO system, each of a transmission apparatus and a reception apparatus includes a plurality of antennas, and sets packet signals to be transmitted in parallel (hereinafter, each of data to be transmitted in parallel in a packet signal is referred to as a “sequence”. ). That is, the data rate is improved by setting a sequence up to the maximum number of antennas for communication between the transmission device and the reception device.

  Furthermore, when such an 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. When performing adaptive modulation, the transmitting apparatus generally notifies the receiving apparatus of information relating to the current data rate (hereinafter referred to as “rate information”). The rate information includes information on the modulation scheme, information on the coding rate, and information on the number of sequences. When receiving the rate information, the receiving apparatus sets the modulation method, coding rate, and number of sequences according to the rate information, and then demodulates the data.

  On the other hand, when CSMA (Carrier Sense Multiple Access) is executed when the base station apparatus multiplexes communications with a plurality of terminal apparatuses, the interval between transmitted packet signals is a period for performing carrier sense. It is defined based on However, in order to improve the transmission efficiency, it is desirable to define the packet signal transmission interval to be short. Therefore, in a predetermined period, one base station signal occupies a band and continuously transmits a plurality of packet signals. Further, improvement in transmission efficiency can be realized by including data for a plurality of terminal devices in one packet signal. Even in such a situation, when adaptive modulation is performed on each piece of data, rate information corresponding to each piece of data should also be transmitted.

  Under such circumstances, the present inventor has come to recognize the following problems. The rate information is defined by a plurality of bits, and standard rate information (hereinafter referred to as “standard rate information”) may be defined by some of the plurality of bits. For example, rate information is defined by 7 bits, and standard rate information is defined by 5 bits. At this time, the maximum 32 data rate values are shown as standard rate information. Furthermore, additional rate information (hereinafter referred to as “additional rate information”) is defined using the remaining bits. Note that the standard rate information can be processed by all the receiving devices, but the additional rate information cannot be processed by all the receiving devices. That is, if there is a receiving apparatus that can process the additional rate information, there is also a receiving apparatus that cannot process the additional rate information.

  Such rate information is included in the control signal, and the control signal is included in the packet signal along with the data. The control signal also includes information on the length of data (hereinafter referred to as “length information”). In general, a receiving apparatus, for example, a terminal apparatus, transmits a data transmission period (hereinafter referred to as a “transmission period”) based on the data rate indicated in the rate information and the data length indicated in the length information. )). Furthermore, the terminal device does not perform packet signal transmission over the derived transmission period. As a result, collision of packet signals is avoided. At this time, if the rate information is additional rate information, the terminal device cannot derive the transmission period unless it understands the content of the additional rate information.

  On the other hand, as described above, when it is defined that the packet signal transmission interval is shortened over a predetermined period, it is possible to include information on the predetermined period in the leading packet signal. When the terminal device cannot understand the content of the additional rate information, the terminal device sets a transmission period based on information regarding a predetermined period. Generally, in order to reduce the collision probability, information regarding a predetermined period is set to be longer than an actual period. Therefore, the transmission period set based on such a period is not an accurate value.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a transmission period set in a terminal device that cannot understand additional rate information when continuously transmitting data to a plurality of terminal devices. It is to provide a transmission technique and a reception technique that improve accuracy.

  In order to solve the above-mentioned problem, a base station apparatus according to an aspect of the present invention transmits a plurality of data signals to a plurality of terminal apparatuses at a variable data rate over a predetermined period. An input unit for inputting a plurality of data signals, a reception unit for receiving speed information indicating a data speed when transmitting each of the plurality of data signals input in the input unit, and a reception unit A transmission unit that transmits a plurality of data signals while associating the speed information with the data signals input in the input unit is provided. The speed information received in the reception unit includes required speed information for indicating the data speed specified as the required data speed or additional speed information for indicating the data speed specified as the additional data speed. The transmission unit transmits the data signal associated with the additional speed information after transmitting the data signal associated with the required speed information.

  The “essential data rate” is a data rate that should be supported by the terminal device, and is a data rate that is typically supported by the terminal device. The “additional data rate” is a data rate that any of the terminal devices supports, and is not necessarily a data rate that the terminal device should not support. Therefore, it can be said that the additional data rate is a data rate that is additionally defined with respect to the essential data rate.

  According to this aspect, since the data signal corresponding to the additional speed information is transmitted after the data signal corresponding to the required speed information is transmitted first, even for the terminal device that does not correspond to the additional speed information, The speed information can be notified in the vicinity of the timing at which the data signal arrives at the terminal device.

  The transmission unit transmits a control signal in each preceding stage of the plurality of data signals, and the speed information corresponding to the data signal and the length of the data signal are added to the control signal arranged in the preceding stage of the data signal. And length information for indicating. In this case, since the speed information and the length information are included, it is possible to notify the terminal device of the period during which the data signal is transmitted.

  The transmission unit generates a packet signal while associating the control signal corresponding to the data signal and the data signal, and transmits a plurality of packet signals, and the first packet among the generated packet signals Information for indicating a predetermined period is included in the signal. In this case, since information for indicating the predetermined period is included in the head packet signal, the terminal apparatus can be notified of the predetermined period even when the terminal apparatus cannot understand the speed information.

  The transmission unit generates a packet signal while associating the control signal corresponding to the data signal with the data signal, and transmits each of the plurality of packet signals. Among the generated plurality of packet signals, an additional speed Information for indicating at least the remaining period of the predetermined period is included in the packet signal in which the information is included in the control information. In this case, since information for indicating a predetermined period is included in the packet signal including the additional speed information, even if the terminal apparatus cannot understand the additional speed information, the terminal apparatus has a predetermined period. Can be notified.

  Another aspect of the present invention is a terminal device. The apparatus includes: a receiving unit that receives a plurality of data signals transmitted at a variable data rate over a predetermined period; and a control signal added to each of the plurality of data signals; Stop processing for data signals that are not destined for the processing unit that processes the data signal that is destined for the data signal and the data signals that are received by the receiving unit And a determination unit for determining. The control signal received by the receiving unit includes speed information indicating the data speed and length information indicating the length of the data signal, and the speed information is defined as an essential data speed. Required speed information for indicating a data rate or additional speed information for indicating a data rate defined as an additional data rate is included, and the determining unit obtains the required speed information from the control signal. When it is extracted, a period for stopping processing is determined in the period determined based on the extracted speed information and length information, and it is added separately when additional speed information is extracted from the control signal. A period for stopping the processing is determined based on the information for indicating the predetermined period.

  According to this aspect, since the information for indicating the predetermined period is included, the predetermined period can be determined even when the terminal device cannot understand the additional speed information.

  Yet another embodiment of the present invention is a communication system. This communication system includes a plurality of terminal devices and a base station device that transmits each of a plurality of data signals to the plurality of terminal devices over a predetermined period at a variable data rate. The base station apparatus includes an input unit that inputs a plurality of data signals, a reception unit that receives speed information indicating a data rate when transmitting each of the plurality of data signals input in the input unit, and a reception unit that receives the data. A transmission unit that transmits a plurality of data signals while associating the speed information with the data signal input in the input unit. The speed information received in the reception unit includes required speed information for indicating the data speed specified as the required data speed or additional speed information for indicating the data speed specified as the additional data speed. The transmission unit transmits the data signal associated with the additional speed information after transmitting the data signal associated with the required speed information.

  According to this aspect, since the data signal corresponding to the additional speed information is transmitted after the data signal corresponding to the required speed information is transmitted first, even for the terminal device that does not correspond to the additional speed information, The speed information can be notified in the vicinity of the timing at which the data signal arrives at the terminal device.

  Yet another embodiment of the present invention is a transmission method. In this method, each of a plurality of data signals can be varied for a plurality of terminal apparatuses over a predetermined period while associating the data signal with the speed information indicating the data speed at the time of transmitting the data signal. A transmission method for transmitting at a data rate of the above, wherein the speed information indicates the required speed information for indicating the data speed specified as the required data speed or the data speed specified as the additional data speed Additional speed information is included, and after the data signal associated with the essential speed information is transmitted, the data signal associated with the additional speed information is transmitted.

  A control signal is transmitted in each preceding stage of the plurality of data signals, and the control signal arranged in the preceding stage of the data signal is used to indicate speed information corresponding to the data signal and the length of the data signal. Length information may be included. A packet signal is generated while associating a control signal corresponding to the data signal with the data signal, and a plurality of packet signals are transmitted, and a predetermined packet signal is added to the first packet signal among the generated packet signals. Information for indicating the period may be included. A packet signal is generated while associating a control signal corresponding to the data signal with the data signal, and a plurality of packet signals are transmitted, and among the generated packet signals, additional speed information is control information. May include information for indicating at least the remaining period of the predetermined period.

  Yet another embodiment of the present invention is a reception method. The method includes a step of receiving a plurality of data signals transmitted at a variable data rate over a predetermined period and a control signal added to each of the plurality of data signals; Among them, the method includes a step of processing a data signal addressed to itself, and a step of deciding to stop processing a data signal not addressed to itself among a plurality of received data signals. The control signal received in the receiving step includes speed information indicating the data speed and length information indicating the length of the data signal, and the speed information defines the required data speed. Required speed information for indicating the data rate specified or additional speed information for indicating the data rate specified as the additional data rate is included, and the step of determining the required speed from the control signal When extracting information, when determining the period for stopping the process in the period determined based on the extracted speed information and length information, and extracting additional speed information from the control signal, A period for stopping the process is determined on the basis of information for indicating a predetermined period added separately.

  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.

  ADVANTAGE OF THE INVENTION According to this invention, when transmitting data to a several terminal device continuously, the precision of the transmission period set in the terminal device which cannot understand additional rate information can be improved.

  Before describing the present invention in detail, an outline will be described. Embodiments of the present invention relate to a MIMO system composed of at least two wireless devices. One of the wireless devices corresponds to a base station device, and the other corresponds to a terminal device. The base station apparatus generates a packet signal composed of a plurality of sequences. In addition, the base station apparatus basically executes CSMA for a plurality of terminal apparatuses. Furthermore, in order to improve transmission efficiency, the base station apparatus occupies a radio band over a predetermined period and continuously transmits a plurality of packet signals. Note that continuous transmission includes transmission of a packet signal at an interval shorter than a normal transmission interval even if it is not completely continuous. Here, the latter is the object of description, and a known technique may be used for CSMA, and thus description thereof is omitted.

  The base station apparatus variably sets the data rate when transmitting a packet signal to each of the plurality of terminal apparatuses. Here, the data rate is determined by setting the modulation scheme, coding rate, number of sequences, and the like. The base station apparatus includes rate information for indicating the data rate in the packet signal. As described above, the rate information includes standard rate information or additional rate information. The packet signal also includes length information, and the terminal device derives a transmission period from the rate information and the length information, and does not perform transmission processing over the transmission period. The terminal device may stop the reception process over the transmission period for the purpose of reducing power consumption.

  Here, if the terminal device can understand the standard rate information but cannot understand the additional rate information, the transmission period cannot be set by the above processing. At that time, the length information corresponding to the period during which the packet signal is continuously transmitted (hereinafter referred to as “conventional length information”) is included in the first packet signal among the continuously transmitted packet signals. The terminal device sets the transmission period according to the conventional length information. As described above, since the conventional length information is set to a value that is longer than the actual transmission period, the transmission period set based on the conventional length information is not accurate. In particular, when stopping the reception operation based on the transmission period, if the packet signal addressed to itself is included in the transmission period, the terminal device cannot receive the packet signal. In order to cope with this, the base station apparatus executes the following processing. In addition, the process at the time of a base station apparatus notifying rate information to a terminal device is demonstrated here. Therefore, a known technique may be used for the process for determining the rate information described above, and the description thereof is omitted here.

  When transmitting the packet signal continuously, the base station apparatus transmits the packet signal associated with the standard rate information, and then transmits the packet signal associated with the additional rate information. Therefore, since the packet signal for the terminal device that cannot understand the additional rate information is arranged in the front part of the continuously transmitted packet signal, the terminal device can understand the rate information included in the packet signal. . As a result, the terminal device can accurately set the transmission period. On the other hand, since the packet signal corresponding to the additional rate information is transmitted in the rear portion of the continuously transmitted packet signal, the terminal device cannot understand the rate information continuously. As a result, an accurate transmission period is not set, but since a packet signal for the terminal apparatus does not arrive in the rear part, an influence due to an inaccurate transmission period is reduced.

  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 a system that does not support the MIMO system (hereinafter referred to as “conventional system”), 52 subcarriers from subcarrier numbers “−26” to “26” are defined. An example of a conventional system is a wireless LAN compliant with the IEEE802.11a standard. Further, one signal unit composed of a plurality of subcarriers and one signal unit in the time domain is referred to as an “OFDM symbol”.

  Each subcarrier is modulated by a variably set modulation method. As the modulation method, any one of BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and 64 QAM 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 data to be transmitted in parallel is set variably. As a result, the data rate is also variably set by variably setting the modulation scheme, coding rate, and number of sequences. The “data rate” may be determined by any combination of these, or may be determined by one of them. In the conventional system, when the modulation method is BPSK and the coding rate is 1/2, the data rate is 6 Mbps. On the other hand, when the modulation method is BPSK and the coding rate is 3/4, the data rate is 9 Mbps.

  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. Here, the first radio apparatus 10a corresponds to a transmission apparatus and a base station apparatus, and the second radio apparatus 10b corresponds to a reception apparatus and a terminal apparatus.

  As a 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 a plurality of series of 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 a plurality of series of data by 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 a plurality of series of data.

  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 first radio apparatus 10a and the second radio apparatus 10b may be reversed.

  FIG. 3 shows an arrangement of packet signals transmitted in the communication system 100. FIG. 3 shows a plurality of packet signals transmitted from the first radio apparatus 10a of FIG. 2, that is, the base station apparatus. Here, for the sake of clarity, it is assumed that five packet signals “packet signal 1” to “packet signal 5” are to be transmitted. Further, the number of sequences in “packet signal 3” is “1”, the number of sequences in “packet signal 1” and “packet signal 4” is “2”, and “packet signal 2” "And" packet signal 5 "the number of series is" 3 ".

  Further, it is assumed that the interval between adjacent packet signals is “T”. Here, it is assumed that the interval “T” is a period shorter than a period required for carrier sense. That is, since a terminal device (not shown) performs carrier sense in a period longer than the interval “T”, transmission of a packet signal cannot be started during the interval “T”. As a result, the base station apparatus can continuously transmit a plurality of packet signals, which corresponds to occupying the band over a period in which the plurality of packet signals are to be transmitted. Although details will be described later, a dummy packet length corresponding to the transmission period as shown in FIG. 3 (as described above, “conventional length” is included in the L-SIG included in the first packet signal. Information ”) has been inserted. As a result, the wireless device 10 to which no packet signal is transmitted can understand the period until the transmission is completed as shown in FIG. 3, so that the transmission is stopped and signal collision is reduced.

  When the base station apparatus transmits a continuous packet signal as shown in FIG. 3, the base station apparatus arranges the packet signal including the standard rate information in front of the packet signal including the additional rate information. Place behind. For example, “packet signal 1” to “packet signal 3” include standard rate information, and “packet signal 4” and “packet signal 5” include additional rate information. Further, as described above, the “packet signal 1” includes conventional length information.

  4A to 4C show packet formats in the communication system 100. FIG. 4A to 4C show a format for the first packet signal among the packet signals 1 of FIG. 3, that is, packet signals transmitted continuously. 4A corresponds to the case where the number of series is “4”, FIG. 4B corresponds to the case where the number of series is “3”, and FIG. 4C corresponds to the case where the number of series is “3”. This corresponds to the case where the number of is “2”. In FIG. 4A, it is assumed that data included in the four sequences is to be transmitted, and packet formats corresponding to the first to fourth sequences are shown in order from the top to the bottom.

  In the packet signal corresponding to the first stream, “L-STF”, “HT-LTF”, and the like are arranged as preamble signals. “L-STF”, “L-LTF”, “L-SIG”, “HT-SIG” are known signals for AGC setting, known signals for transmission path estimation, control signals, MIMO systems corresponding to conventional systems Correspond to the control signals corresponding to. The control signal corresponding to the conventional system includes conventional length information, and the control signal corresponding to the MIMO system includes rate information and length information. “HT-STF” and “HT-LTF” correspond to a known signal for AGC setting and a known signal for channel estimation corresponding to the MIMO system. On the other hand, “data 1” is a data signal. Note that L-LTF and HT-LTF are used not only for AGC setting but also for timing estimation.

  Also, in the packet signal corresponding to the second stream, “L-STF (−50 ns)”, “HT-LTF (−400 ns)” and the like are arranged as preamble signals. Further, in the packet signal corresponding to the third stream, “L-STF (−100 ns)”, “HT-LTF (−200 ns)”, and the like are arranged as preamble signals. In the packet signal corresponding to the fourth stream, “L-STF (−150 ns)”, “HT-LTF (−600 ns)”, and the like are arranged as preamble signals.

  Here, “−400 ns” or the like indicates a timing shift amount in CDD (Cyclic Delay Diversity). CDD is a process in which a waveform in the time domain is shifted backward by a shift amount in a predetermined section, and a waveform pushed out from the last part of the predetermined section is cyclically arranged at the head portion of the predetermined section. That is, “L-STF (−50 ns)” is cyclically shifted with a delay amount of −50 ns with respect to “L-STF”. Note that L-STF and HT-STF are configured by repetition of a period of 800 ns, and other HT-LTFs and the like are configured by repetition of a period of 3.2 μs. Here, “data 1” to “data 4” are also CDDed, and the timing shift amount is the same value as the timing shift amount in the HT-LTF arranged in the preceding stage.

  In the first stream, HT-LTFs are arranged in the order of “HT-LTF”, “−HT-LTF”, “HT-LFT”, and “−HT-LTF” from the top. Here, these are sequentially referred to as “first component”, “second component”, “third component”, and “fourth component” in all series. If the calculation of the first component-second component + third component-fourth component is performed on all series of received signals, the receiving apparatus extracts a desired signal for the first series. Further, if the calculation of the first component + second component + third component + fourth component is performed on all series of received signals, the receiving apparatus extracts a desired signal for the second series. Further, if the calculation of the first component-second component-third component + fourth component is performed on all series of received signals, the receiving apparatus extracts a desired signal for the third series. Also, if the calculation of the first component + second component−third component−fourth component is performed on the received signals of all sequences, the desired signal for the fourth sequence is extracted in the receiving apparatus. These correspond to the combination of codes of predetermined components having an orthogonal relationship between sequences. The addition / subtraction process is executed by vector calculation.

  In the part from “L-LTF” to “HT-SIG” and the like, “52” subcarriers are used as in the conventional system. Of the “52” subcarriers, “4” subcarriers correspond to pilot signals. On the other hand, “56” subcarriers are used in the subsequent parts such as “HT-LTF”.

  In FIG. 4A, the sign of “HT-LTF” is defined as follows. The codes are arranged in the order of “+”, “−”, “+”, “−” in order from the top of the first sequence, and the codes are “+”, “+”, “+” in order from the top of the second sequence. Arranged in the order of “+” and “+”, the codes are arranged in the order of “+”, “−”, “−” and “+” in order from the top of the third series, and from the top of the fourth series. In order, the codes are arranged in the order of “+”, “+”, “−”, and “−”. However, the code | symbol may be prescribed | regulated as follows. The codes are arranged in the order of “+”, “−”, “+”, “+” in order from the top of the first sequence, and the codes are “+”, “+”, “+” in order from the top of the second sequence. Arranged in the order of “−” and “+”, the codes are arranged in the order of “+”, “+”, “+”, “−” in order from the top of the third series, and from the top of the fourth series. In order, the symbols are arranged in the order of “−”, “+”, “+”, “+”. Even such a code corresponds to a combination of codes of predetermined components having an orthogonal relationship between sequences.

  FIG. 4B corresponds to the first to third sequences in FIG. FIG. 4C is similar to the first series and the second series in the packet format shown in FIG. Here, the arrangement of “HT-LTF” in FIG. 4B is different from the arrangement of “HT-LTF” in FIG. That is, the HT-LTF includes only the first component and the second component. In the first sequence, HT-LTFs are arranged in the order of “HT-LTF” and “HT-LTF” from the top, and in the second sequence, HT-LTFs are arranged from the top to “HT-LTF”, “− They are arranged in the order of “HT-LTF”. If the calculation of the first component + the second component is performed on the reception signals of all sequences, the reception device extracts the desired signal for the first sequence. Also, if the first component-second component calculation is performed on all series of received signals, the receiving apparatus extracts a desired signal for the second series. These can also be said to be orthogonal as described above.

  FIGS. 5A to 5C show other packet formats in the communication system 100. FIG. FIGS. 5A to 5C show formats for packet signals 2 to 5 in FIG. 3, that is, the second and subsequent packet signals among the packet signals transmitted continuously. In FIG. 5A, “L-STF”, “L-LTF”, and “L-SIG” in FIG. 4A are not arranged. That is, a signal for maintaining compatibility with the conventional system is not arranged. Instead, since “L-STF” or the like is not arranged in FIG. 5A, the transmission efficiency of the packet signal is improved as compared with FIG.

  In the first sequence, “HT-STF” is followed by four “HT-LTF” and the like similar to FIG. 4A, but the first “HT-LTF” and the second “HT-STF” are arranged. “HT-SIG” is arranged between “−HT-LTF”. Further, “Data 1” is arranged at the subsequent stage of four “HT-LTF” and the like. For the second to fourth sequences, signals that have been subjected to CDD at −400 ns, −200 ns, and −600 ns are arranged in the first sequence, respectively. FIG. 5B shows a format corresponding to FIG. FIG. 5C is similar to the first series and the second series in the packet format shown in FIG. That is, FIG. 5C has a format corresponding to FIG.

  FIG. 6 is a diagram illustrating a packet format of a packet signal finally transmitted in the communication system. FIG. 6 corresponds to a case where the packet signal of FIGS. 4A to 4C is modified. Here, in the case where FIG. 4C is modified, “HT-STF” and thereafter are shown. An operation using an orthogonal matrix (described later) is performed on “HT-STF” and “HT-LTF” arranged in the first sequence and the second sequence in FIG. As a result, “HT-STF4” is generated from “HT-STF1”. The same applies to “HT-LTF”. Further, CDD with timing shift amounts “0 ns”, “−50 ns”, “−100 ns”, and “−150 ns” is performed for each of the first to fourth streams. The absolute value of the timing shift amount at the second CDD is set to be smaller than the absolute value of the timing shift amount at the first CDD for HT-STF and HT-LTF. Similar processing is executed for “HT-LTF” arranged in the third series and the fourth series, “data 1” of the first series, and the like. Similar modifications are made to FIGS. 5A to 5C.

  FIG. 7 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, a baseband processing unit 22, a modem unit 24, an IF unit 26, and a control unit 30, which are collectively referred to as a radio unit 20. Including. 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 is configured in the same manner as the first radio apparatus 10a. Therefore, in the following description, the description related to the reception operation corresponds to the process in the second radio apparatus 10b, and the description related to the transmission operation corresponds to the process in the first radio apparatus 10a.

  As a reception operation, the radio unit 20 performs frequency conversion on a radio frequency signal received by the antenna 12 and derives a baseband signal. The radio unit 20 outputs the baseband signal to the baseband processing unit 22 as a time domain signal 200. In general, baseband signals are formed by in-phase and quadrature components, so they should be transmitted by two signal lines. Here, only one signal line is used for the sake of clarity. Shall be shown. An AGC and A / D converter are also included. The AGC sets the amplification factor in “L-STF” and “HT-STF”.

  As a transmission operation, the radio unit 20 performs frequency conversion on the baseband signal from the baseband processing unit 22 and derives a radio frequency signal. Here, a baseband signal from the baseband 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. That is, the radio unit 20 transmits a radio frequency packet signal from 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.

  As a reception operation, the baseband 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 baseband processing unit 22 outputs the result of adaptive array signal processing as the frequency domain signal 202. One frequency domain signal 202 corresponds to each of a plurality of transmitted sequences. Further, as a transmission operation, the baseband processing unit 22 receives a frequency domain signal 202 as a frequency domain signal from the modulation / demodulation unit 24, converts the frequency domain signal to the time domain, and transmits the frequency domain signal to each of the plurality of antennas 12. The time domain signal 200 is output while being associated.

  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 frequency domain signals are arranged in the order of subcarrier numbers to form a serial signal.

  FIG. 8 shows the configuration of a signal in the frequency domain. Here, one combination of subcarrier numbers “−28” to “28” shown in FIG. 1 is referred to as an “OFDM symbol”. 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 OFDM symbol is arranged before the “i” th OFDM symbol, and the “i + 1” th OFDM symbol is arranged after the “i” th OFDM symbol. And In addition, in the part such as “L-SIG” in FIG. 4A and the like, a combination of subcarrier numbers “−26” to “26” is used for one “OFDM symbol”.

  Returning to FIG. In addition, the baseband processing unit 22 performs CDD to generate a packet signal corresponding to the packet formats of FIGS. 4 (a)-(c) and FIGS. 5 (a)-(c). Further, the baseband processing unit 22 performs steering matrix multiplication in order to perform transformation into the packet signal shown in the packet format of FIG. Details of these processes will be described later.

  The modem unit 24 performs demodulation and deinterleaving on the frequency domain signal 202 from the baseband processing unit 22 as reception processing. Note that demodulation is performed in units of subcarriers. The modem unit 24 outputs the demodulated signal to the IF unit 26. Further, the modem unit 24 performs interleaving and modulation as transmission processing. The modem unit 24 outputs the modulated signal to the baseband processing unit 22 as the frequency domain signal 202. It is assumed that the modulation scheme is specified by the control unit 30 during the transmission process.

  As reception processing, the IF unit 26 combines signals from the plurality of modulation / demodulation units 24 to form one data stream. Furthermore, one data stream is decoded. The IF unit 26 outputs the decoded data stream. In addition, the IF unit 26 receives and encodes one data stream as transmission processing, and then separates it. Further, the IF unit 26 outputs the separated data to the plurality of modulation / demodulation units 24. It is assumed that the coding rate is specified by the control unit 30 during the transmission process. Here, an example of encoding is convolutional encoding, and an example of decoding is Viterbi decoding.

  The control unit 30 controls the timing of the first radio apparatus 10a. The control unit 30 cooperates with the IF unit 26, the modem unit 24, and the baseband processing unit 22, as shown in FIGS. 3, 4A to 5C, 5A to 5C, and FIG. A packet signal is generated, and control for transmitting the generated packet signal is executed. The IF unit 26 inputs a plurality of data. Here, the plurality of data is data to be transmitted to each of the plurality of terminal devices. Here, as described above, it is assumed that a plurality of data is continuously transmitted over a predetermined period. Each of the plurality of data should be transmitted at a variable data rate, and the control unit 30 receives in advance the rate information for transmitting each of the plurality of data.

  As described above, the rate information includes information on the modulation scheme, information on the coding rate, and information on the number of sequences, and the data rate is indicated by a combination thereof. Also, these optimum values should be determined according to the wireless transmission path characteristics. Here, the control unit 30 of the base station apparatus accepts in advance, as rate information, a request value for the data rate for transmission from the terminal apparatus. Further, the control unit 30 stores the received rate information in a storage medium (not shown). As described above, a known technique may be used as a method for the terminal device to determine the required value. Therefore, description of the method for determining the required value is omitted. Also, standard rate information and additional rate information are defined as rate information.

  Here, the standard rate information is indispensable rate information to be supported by the terminal device, and is configured as 5-bit data. FIG. 9 shows a data structure of standard rate information stored in the control unit 30. FIG. 9 includes a standard rate information column 110, a modulation scheme column 112, a coding rate column 114, and a sequence number column 116. In the standard rate information column 110, values of standard rate information are shown, and 32 types of values from “00000” to “11111” are shown. The modulation method column 112 shows the type of modulation method. For example, BPSK, QPSK, 16QAM, and 64QAM are included. The coding rate column 114 shows the coding rate of convolutional coding. The number of series column 116 shows the number of series. Here, it is assumed that any value from “1” to “4” is shown. As illustrated, any value in the standard rate information column 110 is associated with a specific modulation scheme, a specific coding rate, and a specific number of sequences. For example, “00000” is associated with “BPSK” as the modulation scheme, “1/2” as the coding rate, and “1” as the number of sequences.

  Further, the additional rate information is rate information such that a corresponding terminal device exists and a non-compatible terminal device also exists. FIG. 10 shows a data structure of additional rate information stored in the control unit 30. FIG. 10 includes an additional rate information column 118 and an information content column 120. In the additional rate information column 118, the value of the additional rate information is shown. Since 7-bit values are specified as rate information, 128 values are specified. When the value of the upper 2 bits of the 7-bit value is “0”, the value of the lower 5 bits is defined as the standard rate information described above. On the other hand, the remaining information excluding the standard rate information from the rate information is defined as additional rate information. The additional rate information may include, for example, 256 QAM, such as a modulation scheme not included in the standard rate information. Alternatively, the additional rate information may include a definition that the modulation scheme or the like is different for each series. Here, these values are indicated by “A” to “Z”. Actually, a specific value is shown in the information content column 120 instead of “A” to “Z”.

  Returning to FIG. The control unit 30 associates the rate information with the data. The control unit 30 associates a plurality of data input to the IF unit 26 with any one of “packet signal 1” to “packet signal 5” as shown in FIG. Here, in order to simplify the explanation, it is assumed that one packet signal is transmitted to one terminal device and one data is assigned to one packet signal. One data indicates a group of data to be included in one packet signal. The format of “packet signal 1” formed by the control unit 30, the modem unit 24, and the baseband processing unit 22 is shown in FIGS. 4A to 4C. SIG "is arranged. The control unit 30 includes rate information and length information in “HT-SIG”.

  Further, the control unit 30 includes in the “L-SIG” information indicating a period during which packet signals are continuously transmitted as shown in FIG. Here, as information indicating a period during which packet signals are continuously transmitted, rate information defined in the conventional system (hereinafter referred to as “conventional rate information”) and conventional length information are “L−”. It is included in “SIG”. FIG. 11 shows the data structure of conventional rate information stored in the control unit 30. FIG. 11 includes a conventional rate information column 122, a modulation scheme column 112, and a coding rate column 114. The conventional rate information column 122 shows the value of the conventional rate information. As conventional rate information, a 4-bit value is defined, and eight values are defined. The control unit 30 notifies the terminal device of a period during which packet signals are continuously transmitted, using the conventional rate information and the conventional length information. As described above, in order to reduce the collision probability of packet signals, the control unit 30 sets a period for continuously transmitting packet signals so as to be longer than the actual period.

  On the other hand, the format of “packet signal 2” to “packet signal 5” formed by the control unit 30, the modem unit 24, and the baseband processing unit 22 is shown in FIGS. “HT-SIG” is arranged in the preceding stage. The configuration of “HT-SIG” is the same as in the case of FIGS. Returning to FIG.

  The control unit 30 executes the following processing when assigning a plurality of data to a plurality of packet signals as shown in FIG. If the rate information corresponding to the data is standard rate information, the control unit 30 assigns the data to the forward packet signal among the plurality of packet signals. On the other hand, if the rate information corresponding to the data is additional rate information, the control unit 30 assigns the data to the subsequent packet signal among the plurality of packet signals. By such allocation, the modem unit 24, the baseband processing unit 22, and the radio unit 20 transmit the packet signal including the additional rate information after transmitting the packet signal including the standard rate information.

  The operation when the transmission process is stopped will be described with reference to FIG. Here, the packet format of “packet signal 1” in FIG. 3 is FIG. 4B, and the packet formats of “packet signal 2” to “packet signal 5” are FIGS. 5A to 5C, etc. It is. The L-SIG of “packet signal 1” includes conventional rate information and conventional length information, and HT-SIG includes standard rate information and length information. It is assumed that HT-SIG of “signal 2” and “packet signal 3” also includes standard rate information and length information. On the other hand, it is assumed that HT-SIG of “packet signal 4” and “packet signal 5” includes additional rate information and length information.

  The terminal device that can understand the additional rate information is a period for stopping the transmission process from the standard rate information or additional rate information included in the HT-SIG of each packet signal and the length information, that is, the above-described period. Determine the transmission period. The transmission period is derived by dividing the length of the data indicated by the length information by the value of the data rate indicated by the rate information. Since the control part 30 determines a transmission period, using the information contained in HT-SIG, it can set a transmission period correctly. Further, the terminal device stops transmission processing during the transmission period.

  On the other hand, the terminal device that cannot understand the additional rate information determines the transmission period from the standard rate information and the length information included in “packet signal 1” to “packet signal 3”. Further, the terminal device stops the transmission process over these transmission periods. Since the terminal device cannot understand the additional rate information included in “packet signal 4” and “packet signal 5”, the conventional rate information included in “packet signal 1” for these packet signals. And the conventional length information, the transmission period is determined. Further, the terminal device stops the transmission process over the transmission period.

  The operation for stopping the reception process will be described with reference to FIG. First, a case where the terminal device can understand the additional rate information will be described. The terminal device receives a plurality of packet signals over a predetermined period by the radio unit 20, the baseband processing unit 22, and the modem unit 24. The control unit 30 confirms the destination of the received packet signal, and instructs the baseband processing unit 22 and the like to continue the reception process for the packet signal to which the control unit 30 is directed. It is assumed that the destination of the packet signal is included in the data as a MAC header.

  On the other hand, the control unit 30 instructs the baseband processing unit 22 or the like to stop reception processing for a packet signal that is not the destination of the control unit 30. At that time, the control unit 30 extracts length information and rate information from the HT-SIG. Further, the control unit 30 determines the transmission period from the length information and the rate information. In addition, the terminal device stops the reception process over the transmission period.

  Next, a case where the terminal device cannot understand the additional rate information will be described. Note that the processing when the destination of the received packet signal is itself is the same as the processing described above, and thus the description thereof is omitted. Further, the terminal device receives a plurality of packet signals. Since the forward packet signal includes standard rate information, the terminal device can understand the rate information. Therefore, the terminal apparatus sets the transmission period by the same process as described above. Further, the packet signal destined for the terminal device arrives at the front part of the plurality of packet signals, but since the accurate transmission period is set, the terminal device does not stop even if the processing is temporarily stopped. When the packet signal that becomes is received, the terminal device can receive the packet signal as usual.

  On the other hand, a packet signal including additional rate information arrives at a rear portion of the plurality of packet signals. Since the terminal device cannot understand the rate information, it determines the transmission period based on the conventional rate information and the conventional length information included in “L-SIG”. The transmission period is derived by dividing the data length indicated by the conventional length information by the data rate value indicated by the conventional rate information. Although the transmission period determined in this way is not accurate, since the packet signal addressed to itself does not arrive in the rear part of the plurality of packet signals, the influence of the terminal device is small.

  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. 12 shows the configuration of the baseband processing unit 22. The baseband processing unit 22 includes a reception processing unit 50 and a transmission processing unit 52. The reception processing unit 50 executes a part corresponding to the reception operation among the operations in the baseband processing unit 22. That is, the reception processing unit 50 performs adaptive array signal processing on the time domain signal 200, and for that purpose, derivation of the weight vector of the time domain signal 200 is performed. Further, the reception processing unit 50 outputs the result of array synthesis as the frequency domain signal 202. Note that the reception processing unit 50 may generate a required value based on the frequency domain signal 202. The generation of the request value may be performed by a known technique as described above, and thus description thereof is omitted.

  The transmission processing unit 52 executes a part corresponding to the transmission operation among the operations in the baseband processing unit 22. That is, the reception processing unit 50 generates the time domain signal 200 by converting the frequency domain signal 202. In addition, the transmission processing unit 52 associates a plurality of sequences with the plurality of antennas 12, respectively. Further, the transmission processing unit 52 performs CDD as shown in FIGS. 4A to 4C and FIGS. 5A to 5C, and generates a steering matrix as shown in FIG. Perform the operation. Note that the transmission processing unit 52 finally outputs the time domain signal 200. On the other hand, the transmission processing unit 52 may perform beamforming when transmitting the packet signals shown in FIGS. 4A to 4C and FIGS. 5A to 5C. Since beam forming may be a known technique as described above, description thereof is omitted.

  FIG. 13 shows a configuration of the reception processing unit 50. The reception processing unit 50 includes an FFT unit 74, a weight vector deriving unit 76, a first combining unit 80a, a second combining unit 80b, a third combining unit 80c, and a fourth combining unit 80d, which are collectively referred to as a combining unit 80.

  The FFT unit 74 converts the time domain signal 200 into a frequency domain value by performing FFT on the time domain signal 200. Here, the frequency domain values are configured as shown in FIG. That is, the frequency domain value for one time domain signal 200 is output on one signal line.

  The weight vector deriving unit 76 derives a weight vector for each subcarrier from the value in the frequency domain. The weight vector is derived so as to correspond to each of a plurality of sequences, and the weight vector for one sequence has an element corresponding to the number of antennas 12 for each subcarrier. An adaptive algorithm may be used to derive the weight vector corresponding to each of a plurality of sequences, or transmission path characteristics may be used. For these processes, known techniques are used. Therefore, the description is omitted here. As described above, the weight vector deriving unit 76 calculates the first component−the second component + the third component−the fourth component, the first component + the second component, and the like as described above. Finally, as described above, weights are derived in units of subcarriers, antennas 12 and sequences.

  The synthesizing unit 80 performs synthesis using the frequency domain value converted by the FFT unit 74 and the weight vector from the weight vector deriving unit 76. For example, among the weight vectors from the weight vector deriving unit 76, the weight corresponding to one subcarrier and the weight corresponding to the first series are selected as one multiplication target. The selected weight has a value corresponding to each of the antennas 12.

  As another multiplication target, a value corresponding to one subcarrier is selected from the values in the frequency domain converted by the FFT unit 74. The selected value has a value corresponding to each of the antennas 12. Note that the selected weight and the selected value correspond to the same subcarrier. While being associated with each of the antennas 12, the selected weight and the selected value are respectively multiplied, and the multiplication result is added, whereby a value corresponding to one subcarrier in the first sequence is obtained. Derived. In the first synthesizing unit 80a, the above processing is also performed on other subcarriers, and data corresponding to the first stream is derived. Further, in the second synthesis unit 80b to the fourth synthesis unit 80d, data corresponding to the fourth series is derived from the second series by the same processing. The derived first to fourth sequences are output as the first frequency domain signal 202a to the fourth frequency domain signal 202d, respectively.

ここで、δは、シフト量を示し、ｌは、サブキャリア番号を示している。さらに、行列Ｃと系列との乗算は、サブキャリアを単位にして実行される。すなわち、分散部６６は、Ｌ−ＳＴＦ等内での循環的なタイミングシフトを系列単位に実行する。また、タイミングシフト量は、図４（ａ）−（ｃ）、図５（ａ）−（ｃ）のごとく設定される。 FIG. 14 shows the configuration of the transmission processing unit 52. The transmission processing unit 52 includes a distribution unit 66 and an IFFT unit 68. The dispersion unit 66 associates the frequency domain signal 202 with the antenna 12. The distribution unit 66 performs CDD in order to generate a packet signal corresponding to the packet formats of FIGS. 4 (a)-(c) and FIGS. 5 (a)-(c). CDD is performed as matrix C as follows.

Here, δ indicates a shift amount, and l indicates a subcarrier number. Further, the multiplication of the matrix C and the sequence is executed in units of subcarriers. That is, the distribution unit 66 performs a cyclic timing shift within the L-STF or the like on a sequence basis. Further, the timing shift amount is set as shown in FIGS. 4A to 4C and FIGS. 5A to 5C.

  The distribution unit 66 multiplies each of the packet signals generated as shown in FIGS. 4B to 4C and FIGS. 5B to 5C by a steering matrix to thereby determine the number of packet signal sequences. Is increased to the number of series. Here, the dispersion unit 66 extends the order of the input signal to the number of a plurality of sequences before performing multiplication. In the case of FIG. 4C, since “HT-STF” and the like arranged in the first sequence and the second sequence are input, the number of input signals is “2”. Represented by “Nin”.

  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 distribution unit 66 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、前述のごとく、ＣＤＤを示す。ここで、ＣＤＤにおけるタイミングシフト量は、複数の系列のそれぞれに対して異なるように規定されている。すなわち、第１の系列に対して「０ｎｓ」、第２の系列に対して「−５０ｎｓ」、第３の系列に対して「−１００ｎｓ」、第４の系列に対して「−１５０ｎｓ」のようにタイミングシフト量が規定される。ＩＦＦＴ部６８は、分散部６６からの信号に対してＩＦＦＴを実行し、時間領域信号２００として出力する。 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. Further, C represents CDD as described above. Here, the timing shift amount in the CDD is defined to be different for each of the plurality of sequences. That is, “0 ns” for the first sequence, “−50 ns” for the second sequence, “−100 ns” for the third sequence, “−150 ns” for the fourth sequence, etc. The amount of timing shift is defined in FIG. The IFFT unit 68 performs IFFT on the signal from the dispersion unit 66 and outputs it as a time domain signal 200.

  The operation of the wireless device 10 having the above configuration will be described. When the IF unit 26 of the first radio apparatus 10a receives a plurality of data, the control unit 30 acquires rate information corresponding to each of the plurality of data from the storage medium. The control unit 30 assigns a forward packet signal among a plurality of packet signals to data whose acquired rate information is standard rate information. Moreover, the control part 30 allocates the back packet signal of the several packet signals with respect to the data whose acquired rate information is additional rate information. The modem unit 24, the baseband processing unit 22, and the radio unit 20 continuously transmit a plurality of packet signals.

  The operation of the second radio apparatus 10b will be described assuming that the second radio apparatus 10b cannot understand the additional rate information. The radio unit 20 of the second radio apparatus 10b continuously receives a plurality of packet signals. When the destination of the packet signal is itself, the control unit 30 instructs the baseband processing unit 22 or the like to continue the processing. On the other hand, when the destination of the packet signal is not itself and the standard rate information is included in the HT-SIG, the control unit 30 derives the transmission period based on the standard rate information. The control unit 30 instructs the baseband processing unit 22 and the like to stop processing over the derived transmission period. Furthermore, when the destination of the packet signal is not itself and the additional rate information is included in the HT-SIG, the control unit 30 determines the transmission period based on the conventional rate information included in the L-SIG. To derive. The control unit 30 instructs the baseband processing unit 22 and the like to stop processing over the derived transmission period.

  According to the embodiment of the present invention, since the packet signal including the data corresponding to the standard rate information is continuously transmitted first, even the terminal device that does not support the additional rate information Rate information can be notified in the vicinity of the timing at which the data signal arrives. Further, since the length information and the rate information are included in the control signal, it is possible to notify the terminal device of the period during which the data signal is transmitted. Further, even in a terminal device that does not support additional rate information, standard rate information can be continuously acquired in the vicinity of the timing at which the data signal to the terminal device arrives, so that the transmission period can be accurately derived. Can do. Further, since the transmission period is accurately derived, it is possible to accurately stop the processing in the terminal device.

  In addition, since the stop of the processing in the terminal device can be accurately executed, the packet signal can be transmitted with high transmission efficiency while reducing the collision probability of the packet signal. In addition, since the conventional length information is included in the leading packet signal, the terminal device can be notified of the predetermined period even when the terminal device cannot understand the additional rate information. Further, since the packet signal including the data corresponding to the additional rate information is continuously transmitted at the later timing, the terminal device that does not support the additional rate information has information for indicating a predetermined period. Even if the process is stopped based on the above, the influence on the process can be reduced. In addition, even if the content of the additional rate information is not specified at the current timing and will be specified in the future, it is possible to accurately derive the transmission period even for a terminal device that does not support the additional rate information. Can do.

  Further, since the conventional rate information and the conventional length information are transmitted, the predetermined period can be notified even when the terminal device cannot understand the additional rate information. In addition, since an accurate transmission period can be derived in the vicinity of the timing when the packet signal addressed to itself arrives, reception of the packet signal addressed to itself fails even when the reception operation is stopped over the transmission period. The probability of performing can be reduced. In addition, since the reception process is stopped during a period in which a packet signal that is not the destination is received, power consumption can be reduced.

  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 case where the number of the plurality of sequences is “4” has been described. However, the present invention is not limited to this. For example, the number of the plurality of streams may be smaller than “4” or larger than “4”. Accordingly, in the former case, the number of antennas 12 may be smaller than “4”, or the number of antennas 12 may be larger than “4”. According to this modification, the present invention can be applied to various numbers of series.

  In the embodiment of the present invention, the control unit 30 uses the packet format shown in FIGS. 4A to 4C for the leading packet signal. That is, the L-SIG is arranged in the first packet signal, and the terminal apparatus is made to estimate the transmission period based on the conventional rate information and the conventional length information arranged in the L-SIG. However, the present invention is not limited to this. For example, the control unit 30 may add L-SIG to a packet signal in which additional rate information is included in HT-SIG among a plurality of packet signals to be transmitted. That is, the packet format shown in FIGS. 4A to 4C may be used for a packet signal in which additional rate information is included in HT-SIG. At this time, the conventional length information included in the L-SIG may correspond to the remaining period of the period in which the packet signal is continuously transmitted. According to this modification, the estimation accuracy can be improved even when the transmission period is estimated based on the conventional rate information and the conventional length information. That is, it is only necessary to include information of a period that can be understood by a terminal device that cannot understand additional rate information.

  In the embodiment of the present invention, the communication system 100 continuously transmits a plurality of packet signals. However, the present invention is not limited to this. For example, the communication system 100 may combine a plurality of data signals into one packet signal and then transmit the packet signal. FIG. 15 shows still another packet format in the communication system 100. FIG. 15 corresponds to the case where the number of series is “2”. “Data 1” and “Data 2” are the first data, and “HT-SIG” arranged in the preceding stage is a control signal related to the data. “Data 3” and “Data 4” are the second data, and “HT-SIG” arranged immediately before the “Data 3” is a control signal related to the data. “Data N” and “Data N + 1” are the (N + 1) / 2nd data and the last data. According to this modification, the transmission efficiency when transmitting a plurality of data can be improved. That is, a plurality of data may be transmitted continuously.

  In the embodiment of the present invention, a matrix in which each component has an orthogonal relationship is shown as the sign relationship of “HT-LTF” in the training signal. However, the present invention is not limited to this. For example, a matrix having a code relationship that allows each desired component to be extracted by a simple operation such as addition or subtraction even if the components are not orthogonal. That's fine. According to this modification, various code relationships can be used as the code of “HT-LTF” in the training signal.

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. It is a figure which shows arrangement | positioning of the packet signal transmitted in the communication system of FIG. 4A to 4C are diagrams showing packet formats in the communication system of FIG. 5A to 5C are diagrams showing other packet formats in the communication system of FIG. FIG. 3 is a diagram showing a packet format of a packet signal finally transmitted in the communication system of FIG. 2. 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 data structure of the standard rate information memorize | stored in the control part of FIG. It is a figure which shows the data structure of the additional rate information memorize | stored in the control part of FIG. FIG. 8 is a diagram illustrating a data structure of conventional rate information stored in the control unit of FIG. 7. It is a figure which shows the structure of the baseband process part of FIG. It is a figure which shows the structure of the process part for reception of FIG. It is a figure which shows the structure of the process part for transmission of FIG. It is a figure which shows another packet format in the communication system of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 radio | wireless apparatus, 12 antenna, 14 antenna, 20 radio | wireless part, 22 baseband process part, 24 modem part, 26 IF part, 30 control part, 100 communication system.

Claims (5)

A base station device that transmits each of a plurality of data signals at a variable data rate to a plurality of terminal devices over a predetermined period of time,
An input unit for inputting a plurality of data signals;
A receiving unit for receiving speed information indicating a data rate when transmitting each of the plurality of data signals input in the input unit;
Generation for generating a packet signal arranged in the order of the control signal and the data signal while associating the control signal including the speed information received in the reception unit with the data signal input in the input unit on a one-to-one basis And
A transmission unit for transmitting a plurality of packet signals ,
In the speed information received in the reception unit, there is required speed information for indicating the data speed specified as the required data speed, or additional speed information for indicating the data speed specified as the additional data speed. Included,
And the transmission unit, after transmitting a packet signal including the data signal associated with the mandatory-speed information, and transmits the included data signals associated with the additional use velocity information packet signals,
The generation unit includes length information for indicating the length of the corresponding data signal in the control signal included in each packet signal, and includes only the first packet signal among the generated packet signals. A base station apparatus characterized in that information for indicating a period in which a plurality of data signals are to be transmitted is included in the preceding stage of the control signal . A receiving unit that receives a plurality of packet signals over a predetermined period;
Each of the plurality of packet signals received by the receiving unit is arranged in the order of a control signal and a data signal. Among the data signals included in each of the plurality of packet signals received by the receiving unit, A processing unit for processing the data signal,
Among the data signals included in each of the plurality of packet signals received by the reception unit, a determination unit that determines the stop of processing for the data signal that is not the destination of itself,
The control signal included in each of the plurality of packet signals received by the receiving unit includes speed information indicating a data speed and length information indicating a length of the data signal, and the speed The information includes required speed information for indicating the data rate specified as the required data rate, or additional speed information for indicating the data rate specified as the additional data rate,
The receiving unit receives a packet signal including a data signal associated with additional speed information after receiving a packet signal including a data signal associated with essential speed information;
Of the plurality of packet signals received by the receiving unit, only the first packet signal includes information for indicating a period during which a plurality of data signals are transmitted, included in the preceding stage of the control signal,
The determination unit determines a period for stopping processing in a period determined based on the extracted speed information and length information when the essential speed information is extracted from the control signal, and the control signal When the additional speed information is extracted, the period for stopping the processing is determined based on the information for indicating the period during which a plurality of data signals included only in the first packet signal should be transmitted. A terminal device characterized by that. A plurality of terminal devices;
A base station device that transmits each of a plurality of data signals at a variable data rate over a predetermined period to the plurality of terminal devices,
The base station device
An input unit for inputting a plurality of data signals;
A receiving unit for receiving speed information indicating a data rate when transmitting each of the plurality of data signals input in the input unit;
Generation for generating a packet signal arranged in the order of the control signal and the data signal while associating the control signal including the speed information received in the reception unit with the data signal input in the input unit on a one-to-one basis And
A transmission unit for transmitting a plurality of packet signals ,
In the speed information received in the reception unit, there is required speed information for indicating the data speed specified as the required data speed, or additional speed information for indicating the data speed specified as the additional data speed. Included,
And the transmission unit, after transmitting a packet signal including the data signal associated with the mandatory-speed information, and transmits the included data signals associated with the additional use velocity information packet signals,
The generation unit includes length information for indicating the length of the corresponding data signal in the control signal included in each packet signal, and includes only the first packet signal among the generated packet signals. A communication system characterized in that information for indicating a period in which a plurality of data signals are to be transmitted is included in the preceding stage of the control signal . A transmission method for transmitting each of a plurality of data signals at a variable data rate to a plurality of terminal devices over a predetermined period of time,
Inputting a plurality of data signals;
Receiving speed information indicating a data speed when transmitting each of a plurality of input data signals;
Generating a packet signal arranged in the order of the control signal and the data signal while associating the control signal including the received speed information with the input data signal in a one-to-one correspondence;
Each of transmitting a plurality of packet signals,
The speed information received in the step of receiving includes essential speed information for indicating a data speed defined as an essential data speed, or additional speed information for indicating a data speed defined as an additional data speed. Included,
The transmitting step transmits a packet signal including the data signal associated with the additional speed information after transmitting the packet signal including the data signal associated with the required speed information,
The generating step includes the length information for indicating the length of the corresponding data signal in the control signal included in each packet signal, and only the first packet signal among the generated packet signals. In addition, information for indicating a period in which a plurality of data signals should be transmitted is included in the preceding stage of the control signal . Receiving a plurality of packet signals over a predetermined period of time;
Each of the plurality of received packet signals is arranged in the order of the control signal and the data signal, and processes the data signal addressed to itself among the data signals included in each of the received plurality of packet signals. And steps to
A step of deciding to stop processing for a data signal that is not a destination among data signals included in each of a plurality of received packet signals ,
The control signal included in each of the plurality of packet signals received in the receiving step includes speed information indicating a data speed and length information indicating a length of the data signal, and The speed information includes required speed information for indicating the data speed specified as the required data speed, or additional speed information for indicating the data speed specified as the additional data speed,
The receiving step receives a packet signal including a data signal associated with additional speed information after receiving a packet signal including a data signal associated with essential speed information;
Among the plurality of packet signals received in the receiving step, information for indicating a period in which a plurality of data signals are transmitted only in the first packet signal is included in the preceding stage of the control signal,
The determining step determines a period for stopping the process in the period determined based on the extracted speed information and length information when the essential speed information is extracted from the control signal, and is controlled. When the additional speed information is extracted from the signal, the period for stopping the processing is determined based on the information for indicating the period during which a plurality of data signals included only in the first packet signal should be transmitted. And a receiving method.

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