JP2011049836A - Communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate a version of a packet or the like by preamble of the packet, and to change specifications by the version or the like including a part in which control information of the packet is stored. <P>SOLUTION: The communication apparatus has a phase vector setter 15 which gives a phase vector by rotating a phase of a signal in each subcarrier using a specific phase vector regarding transmitted data corresponding to each subcarrier of a multi-carrier signal in a transmitter 10, and sets a phase vector different by the version of the packet, etc. as preamble. The communication apparatus has a phase vector restoration unit 25 which performs reverse rotation of the phase of the signal in each subcarrier of the multi-carrier signal to restore the phase vector in a receiver 20, performs carrier detection using a specific phase vector, discriminates the version of the packet, etc. by a class of a phase vector whose detection is successful, and performs reception processing according to the version, etc. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication apparatus capable of performing communication using a multicarrier communication system such as an OFDM (Orthogonal Frequency Division Multiplexing) system.

  A multi-carrier communication system that transmits information using a plurality of subcarriers such as an OFDM system has a great advantage that high-quality communication is possible even in a harsh transmission path. Wireless communication, power line communication (PLC: It is used for communication using various communication media such as Power Line Communication. The OFDM system uses orthogonal transforms such as FFT (Fast Fourier Transform) and DWT (Discrete Wavelet Transform), arranges multiple carriers at equal intervals on the frequency axis, and multiplexes and transmits signals in parallel. To do. In this OFDM system, the frequency interval of multicarriers is narrowed and multiple carriers can be arranged closely without interfering with each other even though they partially overlap, realizing wideband transmission that efficiently uses a narrow frequency range It is possible.

  FIG. 1 is a diagram illustrating a packet configuration example of a general OFDM signal. An OFDM signal packet transmitted in OFDM communication has a preamble 101, a frame control (FC) 102, and a payload 103 from the head.

  The preamble 101 is added to the beginning of data as a signal for control processing when digital data is transmitted serially, and is composed of known data. For example, a preamble 101 in which a plurality of + 1's are continuously provided for each subcarrier is used. In addition, in order to distinguish the preamble 101 from the beginning of data, a signal in which −1 is provided for each subcarrier at the end of the preamble 101 may be included. In the communication apparatus on the reception side, control processing such as carrier detection for detecting a packet, synchronization timing extraction, and equalization coefficient extraction is performed using a preamble composed of known data. The frame control 102 includes control information such as a tone map index, packet length, transmission source address, transmission destination address, and index necessary for transmission / reception. The frame control 102 is usually subjected to fixed and strong error correction, modulation method, time frequency diversity, and the like. Here, the tone map is a collection of information such as the number of bits of each subcarrier (so-called modulation method) and error correction method, and is determined in advance between the communication device on the transmission side and the communication device on the reception side. And set it. The payload 103 is a portion of the data body to be transmitted, and a tone map and packet length data according to the control information of the frame control 102 are stored in the packet and transmitted.

  Communication systems evolve over time, but it is important to maintain compatibility with past communication systems. Normally, version management is performed so that the version can be identified each time the communication system is updated from the conventional one. The communication device needs to recognize the packet being transmitted, determine which version of the packet is used for communication, and determine the version that the own device will use for communication from now on. At this time, since the functions that can be used are limited depending on the version of the communication method, the functions are upgraded and downgraded according to the version.

  When the communication device determines the version of the packet being used, it is unclear which version of the packet is received, so it is necessary to simultaneously receive all the expected versions of the packet so that they can be received. There is. However, since the demodulation process is an extremely burdensome process, it is difficult to receive simultaneously because of the circuit configuration. For this reason, in general, in the packet configuration, up to a portion containing version information is common specifications, and the subsequent portions are often unique specifications for each version. For example, in the case of the packet configuration of FIG. 1, the version information is stored in the portion of the frame control 102 where the control information is stored. The communication device on the receiving side receives the packet up to the frame control by a common receiving method, and after confirming the version of the packet, receives and demodulates the payload by a method suitable for the corresponding version.

JP 2004-166217 A

  In the conventional version management method as described above, in each version of the packet, the portion where the version information is stored, that is, the portion of the frame control 102 in the example of FIG. For this reason, there is a problem that the characteristics of the frame control part cannot be improved even if the function is improved by updating the version. In addition, when there are different communication methods or versions having different frame control specifications, compatibility between these packets cannot be maintained.

  The present invention has been made in view of the above circumstances, and its purpose is to change the specifications depending on the packet communication method, version, signal type, etc., including the part where the control information of the packet to be transmitted is stored. It is to provide a possible communication device. It is another object of the present invention to provide a communication apparatus that can determine a packet communication method, version, signal type, and the like based on a packet preamble.

  As a first aspect, the present invention provides a communication apparatus that transmits transmission data including a plurality of data and having a preamble, the phase of at least one of the plurality of data is rotated, and the transmission data A phase vector setting unit for setting a phase vector, and multi-carrier modulation based on a predetermined communication method for transmission data for which the phase vector is set by the phase vector setting unit, and generating a transmission signal composed of a plurality of subcarriers A communication apparatus configured to set a phase vector corresponding to the predetermined communication method for data corresponding to the preamble among the plurality of data.

  Moreover, the present invention provides, as a second aspect, the communication apparatus described above, further comprising a control unit that controls a phase vector set by the phase vector setting unit in accordance with a transmission timing of the preamble, and the phase vector The setting unit includes a unit that switches to a phase vector corresponding to the predetermined communication method based on the control of the control unit.

  Moreover, this invention is said communication apparatus as 3rd aspect, Comprising: The said communication apparatus is 1st other communication apparatus which performs communication processing based on 1st communication system, and 2nd communication system The multi-carrier modulation unit performs multi-carrier modulation based on the first communication method or the second communication method, and the control unit performs communication with a second other communication device that performs communication processing based on The first control information is notified to the phase vector setting unit based on the transmission timing of the preamble of the first transmission packet addressed to the first other communication device, and the second address addressed to the second other communication device is addressed. Second control information is notified to the phase vector setting unit based on the transmission timing of the preamble of the second transmission packet, and the phase vector setting unit is based on the first control information and the second control information. The above A first phase vector corresponding to the first communication scheme is set in the preamble of the first transmission packet, and a second phase vector corresponding to the second communication scheme is set in the preamble of the second packet. Including things.

  Moreover, this invention is said communication apparatus as a 4th aspect, Comprising: The said 1st communication system is a communication system using wavelet OFDM, The said 2nd communication system used OFDM. Including those that are communication methods.

  Moreover, this invention is said communication apparatus as 5th aspect, Comprising: The said 1st communication system is a 1st version of the said predetermined communication system, The said 2nd communication system is the said communication system. The second version of the predetermined communication method is included.

  Further, the present invention includes, as a sixth aspect, the communication apparatus described above, wherein the control unit determines the phase vector by a cyclic shift type bit sequence.

  Further, the present invention provides, as a seventh aspect, the communication apparatus described above, wherein the phase vector setting unit sets a phase vector of transmission data of the own apparatus in accordance with a phase vector of data transmitted by another communication apparatus. Includes what to set.

  Moreover, the present invention provides, as an eighth aspect, the communication apparatus described above, wherein the phase vector setting unit determines a phase of transmission data of the own apparatus according to a control signal or data transmitted from an upper apparatus of the network. Includes those that set vectors.

  Moreover, the present invention provides, as a ninth aspect, the communication apparatus as described above, wherein the phase vector setting unit detects a plurality of phase vectors in data transmitted by another apparatus, and detects a phase of an old version or communication method. This includes setting the phase vector of the transmission data of its own device according to the vector.

  The tenth aspect of the present invention is the communication apparatus as described above, wherein the multicarrier modulation unit includes an inverse FFT converter that performs multicarrier modulation using inverse Fourier transform. including.

  Moreover, this invention is said communication apparatus as said 11th aspect, Comprising: The said multicarrier modulation | alteration part is comprised including an inverse wavelet transformer which performs multicarrier modulation using inverse wavelet transformation. including.

  As a twelfth aspect, the present invention provides a receiver that receives a transmission signal composed of a plurality of subcarriers, and multicarrier demodulation that acquires received data by performing multicarrier demodulation on the transmission signal based on a predetermined communication scheme. A phase vector restoring unit that reversely restores the phase of the received data using a phase vector, and carrier detection is performed on the received data whose phase is reversely rotated by the phase vector restoring unit. A carrier detection unit that discriminates the preamble of the received data, and a demodulation processing unit that performs a demodulation process of the received data, wherein the phase vector restoration unit uses the phase vector corresponding to the predetermined communication method. A communication device that restores a phase and performs demodulation processing based on the predetermined communication method is provided.

  Moreover, the present invention provides, as a thirteenth aspect, the communication apparatus described above, comprising a control unit that controls the phase vector used by the phase vector restoration unit based on the predetermined communication method, and the phase vector The restoration unit includes a unit that switches to a phase vector corresponding to the predetermined communication method based on the control of the control unit.

  Moreover, this invention is said communication apparatus as 14th aspect, Comprising: The said receiving part is 1st transmission signal from the 1st other communication apparatus which performs a communication process based on a 1st communication system. And receiving the second transmission signal from the second other communication device that performs communication processing based on the second communication method, and the multicarrier demodulator receives the second transmission signal based on the first communication method. Multi-carrier demodulation of the first transmission signal is performed to obtain first reception data, and multi-carrier demodulation of the second reception data is performed based on the second communication method to obtain second reception data. The control unit switches the third control information corresponding to the first transmission signal and the fourth control information corresponding to the second transmission signal to notify the phase vector restoration unit, and The restoration unit includes the third control information and the 4, the first phase vector corresponding to the first communication method and the second phase vector corresponding to the second communication method are switched, and the first received data and the first In this example, the phase of the received data of 2 is restored.

  Further, the present invention is the communication apparatus according to the fifteenth aspect, wherein the control unit notifies the phase vector restoration unit of the third control information and the fourth control information in time series. The phase vector restoration unit switches the first phase vector and the second phase vector in time series, and the carrier detection unit performs carrier detection using the first phase vector and the second phase. Includes those that perform carrier detection using vectors in time series.

  Moreover, the present invention is the communication apparatus according to the sixteenth aspect, wherein the first communication method is a communication method using wavelet OFDM, and the second communication method is using OFDM. Including those that are communication methods.

  Further, the present invention provides, as a seventeenth aspect, the communication apparatus described above, wherein the first communication method is a first version of the predetermined communication method, and the second communication method is the above-described communication device. The second version of the predetermined communication method is included.

  Moreover, the present invention provides, as an eighteenth aspect, the communication apparatus according to the first aspect, wherein the phase vector restoration unit uses a first phase vector corresponding to the first communication method to rotate the phase. A phase rotator, and a second phase rotator that rotates a phase using a second phase vector corresponding to the second communication method, and the carrier detection unit includes the first phase vector. Including the carrier detection using the second phase vector and the carrier detection using the second phase vector in parallel.

  In addition, the present invention provides, as a nineteenth aspect, the communication apparatus described above, wherein the demodulation processing unit detects a phase that has been successfully detected before when the carrier detection unit succeeds in carrier detection using a plurality of phase vectors. This includes selecting a vector and performing a demodulation process based on a communication method corresponding to the phase vector.

  Moreover, the present invention includes, as a twentieth aspect, the communication apparatus described above, wherein the multicarrier demodulation unit includes an FFT converter that performs multicarrier demodulation using Fourier transform. .

  Moreover, the present invention includes, as a twenty-first aspect, the communication apparatus described above, wherein the multicarrier demodulation unit includes a wavelet transformer configured to perform multicarrier demodulation using wavelet transform. .

Moreover, this invention includes what is said communication apparatus as a 22nd aspect, Comprising: The transmission line which performs data communication is a power line.
Further, the present invention includes, as a twenty-third aspect, the above communication apparatus, wherein the transmission path for performing data communication is a wireless line.

  With the above configuration, the transmission-side communication apparatus sets and transmits the phase vector associated with the communication method in the transmission data preamble, and the reception-side communication apparatus restores the received data phase vector to a specific phase vector. Carrier is detected by detecting a preamble having, and demodulation processing is performed in accordance with the specification of the communication method corresponding to the phase vector that has been successfully detected. In the communication device on the transmission side, information on the phase of the unmodulated signal can be included by the phase vector set in the preamble, so that information on the communication method can be included in the preamble, and data of different communication methods can be included in the phase vector of the preamble. Can be identified. The communication device on the receiving side can determine the phase vector of the received data by setting a specific phase vector and performing carrier detection, and specifications of an appropriate communication method corresponding to the phase vector that has succeeded in carrier detection It is possible to perform demodulation processing according to the above. In this case, the demodulation process can be adapted to correspond to a plurality of different communication methods. Further, by providing information on the phase of the non-modulated signal, the receiving side communication apparatus can reliably determine the phase vector even if the received signal is not synchronized. Further, the packet communication method, version, signal type, etc. can be discriminated by the packet preamble. For this reason, it is possible to change the specifications depending on the packet communication method, version, signal type, etc., including the part where the control information after the preamble in the packet is stored. For example, when updating the version of the communication method, the specification including the control information can be changed to improve the function and performance. Even if the specifications of the control information part are different, the version information can be identified by the phase vector of the preamble, so that compatibility can be ensured.

  ADVANTAGE OF THE INVENTION According to this invention, the communication apparatus which can change a specification by the communication system, version, signal classification, etc. of a packet including the part in which the control information of the packet to transmit is stored can be provided. In addition, it is possible to provide a communication device that can determine a packet communication method, version, signal type, and the like based on a packet preamble.

A diagram showing a packet configuration example of a general OFDM signal The figure which shows the 1st example of the example of a setting of the phase vector which concerns on embodiment of this invention The figure which shows the 2nd example of the setting example of the phase vector which concerns on embodiment of this invention The figure which shows the 3rd example of the setting example of the phase vector which concerns on embodiment of this invention The figure which shows the 4th example of the setting example of the phase vector which concerns on embodiment of this invention The figure which shows the 5th example of the example of a setting of the phase vector which concerns on embodiment of this invention. The block diagram which shows the structure of the principal part of the communication apparatus which concerns on embodiment of this invention. The figure which shows an example of the phase vector used in this embodiment The block diagram which shows the structure of the transmission side apparatus which concerns on the 1st Embodiment of this invention. The block diagram which shows the structure of the receiving side apparatus which concerns on the 1st Embodiment of this invention. The block diagram which shows the structure of the part regarding the phase vector of the receiving side apparatus which concerns on 1st Embodiment. The flowchart which shows the operation | movement of the carrier detection in the receiving side apparatus of 1st Embodiment, and a reception process. The figure which shows an example of the signal point on the complex plane of transmission data The figure which shows an example of the signal point on the complex plane of the received data when the symbol synchronization is taken The figure which shows an example of the signal point on the complex plane of the received data when the symbol synchronization is not taken The block diagram which shows the structural example of the carrier detector of this embodiment The figure which shows the example of the signal point on the complex plane in the carrier detector of this embodiment The block diagram which shows the 1st example of a structure of the correlation distribution calculating unit used by this embodiment. The figure which shows the area | region of the signal point on the complex plane counted in the correlation distribution calculator of FIG. The block diagram which shows the 2nd example of a structure of the correlation distribution calculating unit used by this embodiment. The figure which shows the area | region of the signal point on the complex plane counted in the correlation distribution calculator of FIG. The block diagram which shows the structure of the transmission side apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows the structure of the receiving side apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows the structure of the part regarding the phase vector of the receiving side apparatus which concerns on 2nd Embodiment. The block diagram which shows the structure of the receiving side apparatus which concerns on the 3rd Embodiment of this invention. The flowchart which shows the 1st example of the operation | movement of the carrier detection in the receiving side apparatus of 3rd Embodiment, and a reception process. The flowchart which shows the 2nd example of the operation | movement of the carrier detection and reception process in the receiving side apparatus of 3rd Embodiment. The block diagram which shows the structure of the transmission side apparatus which concerns on the 4th Embodiment of this invention. The block diagram which shows the structure of the receiving side apparatus which concerns on the 4th Embodiment of this invention. The figure which shows the structure of the power line communication system which concerns on 5th Embodiment. The figure which shows the external appearance of the PLC modem which concerns on 5th Embodiment The block diagram which shows an example of the hardware constitutions of the PLC modem which concerns on 5th Embodiment

  A communication apparatus according to an embodiment of the present invention is a communication apparatus capable of communication using a multicarrier communication system such as an OFDM system, and is used in a network in which a plurality of terminals exist and communicate with each other. In the following description, an OFDM communication apparatus is exemplified. Communication signal transmission paths in the network include power lines, network lines, TV antenna lines, wired lines such as telephone lines, wireless lines such as wireless LAN, UWB (Ultra Wide Band), WiMAX (Worldwide Interoperability for Microwave Access), etc. Various communication media can be used.

  In this embodiment, a phase vector to be added to a communication signal is used, information is given to the phase of an unmodulated signal in the preamble, and the packet communication method, version, signal type, etc. are determined by version information associated with the phase vector. Can be determined. For example, between different versions of a certain communication system, each specification of transmission data in each version of the communication system can be discriminated. Here, the version information is assumed not only to identify the version of a specific communication method but also to identification information representing the packet communication method, version, signal type, and the like.

  It is assumed that the preamble transmitted from the communication device on the transmission side has two or more identical continuous data as a known bit string constituting the preamble. For example, it is assumed that a preamble is composed of the same continuous data such as all “1” and all “0”, and an unmodulated signal is transmitted as the preamble. At this time, the phase vector is associated with the communication method, version, signal type, etc. of the packet, and a phase vector is assigned to each version, and a different phase vector is set and used depending on the version of the packet to be transmitted. As a result, the communication device on the receiving side can determine the version of the packet being used by determining the phase vector.

  The preamble is composed of 10 symbols. Several symbols out of 10 are assigned correction information for correcting phase distortion that the OFDM signal packet receives due to noise on the transmission path, or synchronization information used to synchronize the transmission device and the reception device. One symbol includes, for example, 423 subcarriers.

  In the OFDM method, a correct data string cannot be received unless symbol synchronization is established. Therefore, it is assumed that symbol synchronization is established in order to determine version information from the data string. On the other hand, by providing version information with a preamble phase vector as in the present embodiment, it is possible to identify the version of a packet even when symbol synchronization is not achieved.

  2 to 6 are diagrams showing setting examples of the phase vector according to the embodiment of the present invention. The first example of FIG. 2 shows an example of setting a phase vector when different versions of packets are transmitted on the transmission path using the same communication method.

  In the first example, the phase vector A is set in the preamble for one version A packet, and the phase vector B is set in the preamble for the other version B packets. Conventionally, since version information is stored in the control information of the frame control (FC), it is necessary to make the preamble and the frame control common in order to maintain compatibility. On the other hand, in the present embodiment, the carrier interval or the like is a common specification only for the preamble, and the versions can be distinguished by the difference in the phase vector of the preamble. Therefore, even if the versions are different in the same communication method, each version can be recognized, specifications after frame control can be changed, and performance including frame control can be improved while maintaining compatibility between versions. it can.

  The second example of FIG. 3 shows a setting example of the phase vector when packets of different communication methods are transmitted on the transmission path.

  In the second example, the phase vector A is set in the preamble for one scheme A packet, and the phase vector B is set in the preamble for another scheme B packet. Thus, by associating the phase vector with the communication method, the phase vector can be used even between different communication methods. As a specific example of the communication method, for example, in the case of power line communication, the phase vector A is assigned as HD-PLC (registered trademark), and the phase vector B is assigned as HomePlug (registered trademark). Conventionally, packets of different communication schemes could not be identified, but mutual communication schemes can be recognized by setting phase vectors as in this example.

  It is also possible to combine the first example and the second example. In this case, for example, phase vectors A to D are assigned to one method A, and phase vectors E to G are assigned to another method B. Thereby, different communication systems can be identified by discrimination of the phase vector, and different versions can be identified in each communication system. For this reason, it is possible to change the specifications including the frame control portion after the preamble, and the reception side can perform reception processing corresponding to each version of each communication method.

  The third example of FIG. 4 shows a setting example of phase vectors in which different phase vectors are assigned depending on the signal type in the same communication method.

  In the third example, for a signal of a certain communication scheme, a phase vector A is set in the preamble for one signal A packet, and a phase vector B is set in the preamble for another signal B packet. In this way, it is possible to associate a phase vector with a signal type and set different phase vectors for each signal type even in the same communication method or the same version of a packet. As a result, the packet communication method parameters can be switched after frame control depending on the signal type. As a specific example of the signal type, different phase vectors are assigned to a data packet including a data body to be transmitted and an Ack / Nack packet which is a response signal indicating whether data can be received and demodulated. In this case, different parameters such as the carrier interval (that is, the symbol length) and the number of data repetitions in frame control can be used for the data packet and the Ack / Nack packet.

  The fourth example of FIG. 5 shows a setting example of the phase vector when a packet is transmitted on the transmission path.

  The two packets shown in FIG. 5 each have two preambles, and a phase vector is set for the first preamble. For version A or scheme A, a phase vector A is associated. Similarly, phase vector B is associated with version B or scheme B. In this way, by providing one dedicated preamble for setting the phase vector in front of the normal packet, the version and the data without changing the setting of the data after the second preamble (that is, the normal packet) can be obtained. It becomes possible to generate a packet that can identify the difference in the method.

  The fifth example of FIG. 6 shows a setting example of the phase vector when a packet is transmitted on the transmission path.

  Each of the two packets shown in FIG. 6 has three preambles, and phase vectors are set for the first preamble and the second preamble. In the first preamble, a phase vector associated with the scheme is set. Specifically, phase vector A is set for method A, and phase vector B is set for method B. A phase vector associated with the version is set in the second preamble. Specifically, the phase vector C is set for the version C, and the phase vector D is set for the version D. In this way, by providing two dedicated preambles for setting the phase vector before the normal packet, the method and the data without changing the setting of the data after the third preamble (that is, the normal packet) can be obtained. It becomes possible to generate a packet that can identify a difference in version.

  In the example shown in FIG. 6, the phase vector for identifying the method is set in the first preamble and the phase vector for identifying the version is set in the second preamble, but the phase vector for identifying the version in the first preamble. And a phase vector for identifying the method may be set in the second preamble.

  FIG. 7 is a block diagram showing a configuration of a main part of the communication apparatus according to the embodiment of the present invention. In FIG. 7, the transmission device 10 is divided into the transmission device 10 on the transmission side and the reception device 20 on the reception side, but the communication device generally has both functions of the transmission device 10 and the reception device 20. In addition, the configuration example of FIG. 7 illustrates a configuration in the case where a power line communication device (PLC modem) is assumed as the communication device.

  The transmission apparatus 10 includes a multicarrier modulator 11, a D / A converter 12, an analog front end (AFE) 13, and a coupler 14. The multicarrier modulator 11 modulates transmission data of an OFDM multicarrier signal using orthogonal transform such as inverse Fourier transform (IFFT) or inverse wavelet transform (IDWT). The D / A converter 12 converts the modulated multicarrier digital signal into an analog signal and outputs the analog signal. The analog front end 13 passes a signal of a necessary frequency band from the input analog signal. The coupler 14 superimposes the input analog signal on the transmission path 16 and transmits it. The multicarrier modulator 11 uses the phase vector whose phase is randomized by a specific bit sequence for transmission data corresponding to each subcarrier of the multicarrier signal, and rotates the phase of the signal in each subcarrier. A phase vector setting unit 15 for assigning a vector is provided. The multicarrier signal transmitted from the transmission device 10 is transmitted to the reception device 20 via the transmission path 16.

  The receiving device 20 includes a coupler 21, an analog front end 22, an A / D converter 23, and a multicarrier demodulator 24. The coupler 21 separates a predetermined analog signal from the received multicarrier signal. The analog front end 22 passes a signal of a necessary frequency band from the separated analog signal. The A / D converter 23 converts the input analog signal into a digital signal and outputs it. The multicarrier demodulator 24 demodulates the received data of the OFDM multicarrier signal using Fourier transform (FFT) or wavelet transform (DWT). The multicarrier demodulator 24 reversely rotates the phase of the signal in each subcarrier using a phase vector whose phase is randomized by a specific bit sequence for the received data corresponding to each subcarrier of the demodulated multicarrier signal. And a phase vector restoration unit 25 that restores the phase vector to the original state.

  The phase vector is a set of values indicating the phase corresponding to the signal of each subcarrier of the multicarrier signal, and is set so that the phase of the signal in all subcarriers is random. Here, the “phase vector” is a set of values indicating the amount of rotation by which the signal points of the subcarriers constituting the multicarrier signal such as the OFDM signal are rotated on the complex coordinate plane. A combination of values that equalizes the time waveform (suppresses the peak on the time axis). The phase vector includes a fixed value that is a combination of predetermined values and a variable value that is a combination of which values are changed according to a predetermined condition. The predetermined condition includes a cyclic shift and a random value described later. Further, the phase vector is referred to as “carrier phase” as another name. In this case, the fixed value is called “determined stick carrier phase” and the variable value is called “random carrier phase”.

  FIG. 8 is a diagram illustrating an example of a bit sequence used for setting a phase vector. The bit sequence shown in FIG. 8 is a cyclic shift type bit sequence having a value of “0” or “π”. Such a cyclic shift type bit sequence can be generated based on a PN (Pseudo Noise) code or the like. By using a PN code or the like, it is possible to give the characteristics of high autocorrelation and low cross-correlation while randomizing the phase of each subcarrier signal. As shown in FIG. 8, the bit sequence used for setting the phase vector A (first phase vector), the phase vector B, by cyclically shifting one bit sequence having a value of “0” or “π”. It is possible to generate bit sequences used for setting different phase vectors, such as bit sequences used for setting (second phase vector). Therefore, by using a cyclic shift type bit sequence, it is possible to easily generate a different phase vector and change the phase vector. In this case, since only one bit sequence needs to be stored, the memory capacity for holding the phase vector information can be reduced.

  The phase vector is set for each symbol with respect to the preamble, and one phase is given for each subcarrier. The preamble is composed of 10 symbols, and each symbol has, for example, 432 subcarriers. The initial value of the phase of each subcarrier is zero.

  The values “0” and “π” in the bit sequence shown in FIG. 8 indicate the amount of rotation with respect to the phase of each subcarrier. If it is “0”, the phase of the subcarrier does not change. If “π”, the phase of the subcarrier changes by 180 °. This bit sequence has a value indicating the rotation amount by the same number as the number of subcarriers included in one symbol.

  For the subcarriers constituting the preamble, the phase is set using the upper bit sequence (phase vector A) in FIG. When the phase of the subcarrier is set using the upper bit sequence in FIG. 8, the phases of the first to fifth subcarriers are set to 180 °, and the sixth and seventh phases do not change. When such setting is performed up to the 432rd subcarrier, the phase vector A is set for the subcarriers constituting the preamble.

  On the other hand, for the subcarriers constituting the postamble, the phase is set using the lower bit sequence of FIG. The lower bit sequence in FIG. 8 is a cyclic shift of the upper bit sequence in FIG. When the phase of the subcarrier is set using the lower bit sequence in FIG. 8, the phase of the first subcarrier does not change, and the phase of the second to sixth subcarriers is set to 180 °. When such setting is performed up to the 432rd subcarrier, the phase vector B is set for the subcarriers constituting the postamble.

  The phase setting for each subcarrier may be performed sequentially from the first subcarrier to the 432th subcarrier, or may be performed collectively for the 1st to 432th subcarriers.

  In addition, when one phase is given for each of a plurality of subcarriers, it is desirable to give one phase to adjacent subcarriers or a plurality of consecutive subcarriers. The phase vector setting unit 15 can also add a phase vector to transmission data without using a specific bit sequence. For example, if the phase of at least one subcarrier among the subcarriers of the preamble is rotated, a phase vector can be added to the transmission data.

  In the present embodiment, the transmitting device 10 sets and transmits a specific phase vector that differs depending on the communication method, version, signal type, etc., for the preamble of the transmission data packet, and the receiving device 20 restores the phase vector of the received data. Thus, a signal having a specific phase vector corresponding to the preamble is detected. Thus, the preamble can be detected by detecting the signal of a specific phase vector. At this time, phase vector information is shared between the transmitter 10 and the receiver 20. By giving information to the phase of the unmodulated signal by the phase vector, the receiving apparatus 20 can identify the version information embedded in the preamble using the phase vector regardless of the presence or absence of symbol synchronization.

(First embodiment)
FIG. 9 is a block diagram showing the configuration of the transmission side apparatus according to the first embodiment of the present invention. FIG. 9 shows a configuration example of a main part of a communication device that is a transmission-side device in the first embodiment. In this configuration example, inverse Fourier transform (IFFT) is used to modulate a multicarrier signal. The transmission side device includes a symbol mapper 31, a serial / parallel converter (hereinafter referred to as S / P converter) 32, a phase rotator 33, an inverse FFT converter 34, and a parallel / serial converter (hereinafter referred to as P / S). (Described as a converter) 35, a D / A converter 36, and a control unit 37.

  The symbol mapper 31 maps transmission data of serial data to a complex coordinate plane. The symbol mapper 31 converts transmission data based on bit data into symbol data, performs primary modulation, and maps it onto M (M: the number of subcarriers, the same shall apply hereinafter) complex coordinate plane (note that the number of symbol data is Depending on which primary modulation is used). The S / P converter 32 converts serial data into parallel data corresponding to each subcarrier of the multicarrier signal. The S / P converter 32 converts serial data (transmission symbols) after primary modulation that are sequentially input into parallel data corresponding to each subcarrier of the multicarrier signal. Note that the order of the symbol mapper 31 and the S / P converter 32 can be changed.

  The phase rotator 33 rotates the phase of the parallel data corresponding to each subcarrier. The phase rotator 33 rotates the phase of the input parallel data in accordance with a control signal from the control unit 37. That is, the phase is rotated by giving a phase rotation angle of, for example, “0” or “π” for each subcarrier. Here, the maximum number of parallel data whose phases are rotated is M-1. The inverse FFT converter 34 performs IFFT of the parallel data rotated in phase and converts it into the frequency domain. The inverse FFT converter 34 performs multi-carrier modulation by performing inverse Fourier transform on the parallel data of each subcarrier whose phase is rotated, and generates a multi-carrier transmission signal. The P / S converter 35 converts multi-carrier modulated parallel data into serial data. The D / A converter 36 converts the multi-carrier signal of serial data into an analog signal and outputs it.

  The control unit 37 controls the operation of the entire transmission side apparatus and transmission data, supplies a control signal to the phase rotator 33, and controls setting and changing of the phase vector. Specifically, the control unit 37 controls the phase rotation operation in the phase rotator 33 based on the transmission timing of the preamble of the transmission data, and gives a specific phase vector to the transmission data. The control unit 37 includes a bit sequence holding unit and a cyclic shift unit, and uses, for example, a specific bit sequence based on a pseudo-random value having two values “0” and “π” based on the PN sequence. Then, a bit sequence based on a specific cyclic shift amount is generated and supplied to the phase rotator 33 as a phase vector control signal to rotate the phase for each target subcarrier. Thereby, a predetermined phase vector is set.

  At this time, the control unit 37 sets the assigned phase vector according to the version information for identifying the communication method, version, signal type, etc. of the packet to be transmitted. That is, a different phase vector is set according to the version information, and the phase vector of the phase rotator 33 is switched. For example, when the version of the communication method of the packet to be transmitted changes, the control unit 37 outputs a control signal and switches the phase vector of the phase rotator 33. In the preamble, the same data is transmitted in a plurality of consecutive symbols as transmission data. Therefore, in this case, in the preamble, the waveform of the multicarrier transmission signal is a sine wave group. Note that the phase vector of the data part including the frame control and payload after the preamble can take various forms such as the same as the preamble, other phase vectors, and no phase rotation. It is.

  The control unit 37 switches the phase vector according to the transmission data destination. For example, when transmitting transmission data to a communication apparatus that operates in a communication scheme using wavelet OFDM such as HD-PLC (registered trademark), a phase vector A is set for the preamble of the transmission data, and Homeplug (registered trademark) is used. When transmitting transmission data to a communication apparatus that operates in a communication scheme using OFDM, such as), a phase vector B is set for the preamble of the transmission data. Also, for communication between communication devices operating with different versions of the same communication method, for example, communication with a phase vector A set for the preamble of transmission data transmitted to a communication device operating with version 1 and operating with version 2 A phase vector B is set for the preamble of transmission data to be transmitted to the apparatus. The control unit 37 transmits to the phase rotator 33 a first control signal for setting the phase vector A and a second control signal for setting the phase vector B. The phase rotator 33 performs phase rotation of the subcarrier using the phase vector A according to the timing notified of the first control signal, and similarly, the phase vector B according to the timing notified of the second control signal. Is used to rotate the phase of the subcarrier.

  FIG. 10 is a block diagram showing the configuration of the receiving side apparatus according to the first embodiment of the present invention. FIG. 11 is a block diagram illustrating a configuration of a part related to the phase vector of the reception-side apparatus according to the first embodiment. 10 and 11 show a configuration example of a main part of a communication device serving as a reception side device in the first embodiment. In this configuration example, Fourier transform (FFT) is used for demodulation of a multicarrier signal. The receiving side device includes an AGC circuit 41, an A / D converter 42, an S / P converter 43, an FFT converter 44, an antiphase rotator 45, a P / S converter 46, a control unit 47, a carrier detector 48, A synchronization circuit 49, an equalizer 50, a demodulator 51, and a transmission path estimator 52 are included.

  The AGC circuit 41 performs signal amplification while performing AGC (Auto Gain Control) control of the received signal. The A / D converter 42 converts the analog received signal into a digital signal and outputs the digital signal. The S / P converter 43 converts serial data into parallel data corresponding to each subcarrier of the multicarrier signal. The S / P converter 43 converts serial data (received symbols) of received data that is sequentially input into parallel data corresponding to each subcarrier of the multicarrier signal. The FFT converter 44 performs FFT of parallel data and converts it into the time domain. In this FFT converter 44, the parallel data of each subcarrier is Fourier-transformed to perform multicarrier demodulation, and parallel data reception data corresponding to each subcarrier of the multicarrier signal is generated.

  The antiphase rotator 45 rotates the phase of the parallel data corresponding to each subcarrier. In the inverse phase rotator 45, the phase of the input parallel data is rotated in accordance with the control signal from the control unit 47, and the phase of each data is restored. Here, the maximum number of parallel data whose phases are rotated is M-1. The P / S converter 46 converts parallel data corresponding to each subcarrier of the multicarrier signal whose phase has been restored to serial data. Even if the order of the antiphase rotator 45 and the P / S converter 46 is changed, there is no problem in the operation. Further, in the processing after the S / P converter 43, if all parallel processing is performed, the P / S converter 46 becomes unnecessary.

  The control unit 47 controls the operation of the entire receiving apparatus, supplies a control signal to the antiphase rotator 45, and controls setting and changing of the phase vector to be restored. Specifically, the control unit 47 controls the phase rotation operation in the anti-phase rotator 45, and restores the phase rotation of the data of each subcarrier using a specific phase vector. The control unit 47 has a bit sequence holding unit and a cyclic shift unit, for example, using a specific bit sequence based on a pseudo-random value having two values of “0” and “π” based on the PN sequence. Then, a bit sequence with a specific cyclic shift amount is generated and supplied to the anti-phase rotator 45 as a phase vector control signal to rotate the phase for each target subcarrier. In this case, the phase vector control signal has the opposite sign to that of the transmission side apparatus. However, in the above case, the control signal of the phase vector is the same as that of the transmission side device. Thereby, the phase of the data of each subcarrier is restored by the set predetermined phase vector.

  The control unit 47 switches the phase vector according to the transmission source of the received signal. For example, for received data of a received signal received from a communication device that operates in a communication method using wavelet OFDM such as HD-PLC (registered trademark), a phase vector A is set for the preamble of the received data, and Homeplug ( For received data of a received signal received from a communication device that operates in a communication method using OFDM such as registered trademark, a phase vector B is set for the preamble of the received data. Also, for communication between communication devices operating with different versions of the same communication method, for example, the phase vector A is set for the preamble of the received data of the received signal received from the communication device operating with version 1, and version 2 A phase vector B is set for the preamble of the received data of the received signal received from the operating communication device. The control unit 47 transmits a third control signal for setting the phase vector A and a fourth control signal for setting the phase vector B to the anti-phase rotator 35. The anti-phase rotator 35 performs phase rotation of the subcarrier using the phase vector A according to the timing notified of the third control signal, and similarly, the phase vector according to the timing notified of the fourth control signal. Subcarrier phase rotation is performed using B.

  At this time, the control unit 47 sets the phase vector assigned corresponding to the version information such as the communication method, version, and signal type of the received packet assumed to be used. For example, the phase vector of the anti-phase rotator 45 is switched in accordance with a plurality of phase vectors corresponding to the version information that is expected to be transmitted, and the phase is reversely rotated. The phase vector of the data part after the preamble is set according to various aspects of the phase vector of the transmission signal, such as the same as the preamble, other phase vectors, or no phase rotation. That's fine.

  The carrier detector 48 receives serial data received data, performs carrier detection on the signal after the phase vector is restored by a specific phase vector, and determines the preamble by determining the presence or absence of the carrier. The carrier detector 48 outputs a carrier detection signal to the synchronization circuit 49 when a carrier is detected. Details of the carrier detector 48 will be described later. Further, the carrier detector 48 notifies the demodulation processing unit including the equalizer 50, the demodulator 51, and the like, of the type of phase vector used for carrier detection.

  The synchronization circuit 49 receives the serial data reception data, generates a synchronization signal for synchronizing the reception data, and outputs the synchronization signal to the FFT converter 44 and the equalizer 50. The equalizer 50 compares the complex information of the input received data with the known data to obtain an equalization coefficient, and equalizes the complex information. The demodulator 51 demaps the received data after equalization from the complex coordinate plane. The demodulator 51 converts symbol data on the complex coordinate plane into bit data and obtains received data. In the demodulation processing unit such as the demodulator 51, the frame structure, modulation method, parameters, etc. corresponding to the corresponding communication method, version, signal type, etc. are set based on the information of the phase vector detected by the carrier, and the received packet Perform demodulation processing according to specifications. Here, as demodulation processing in the demodulation processing unit, demapping, error correction, relative power difference processing, and the like are performed in order to perform demodulation after the preamble.

  The transmission path estimator 52 receives the output of the equalizer 50 and the output of the demodulator 51, and measures the reception quality of the pilot signal included in the received data, thereby transmitting the transmission path in each subcarrier of the multicarrier signal. Perform channel estimation (channel estimation) to estimate characteristics. The transmission path estimation result by the transmission path estimator 52 is fed back to the transmission side apparatus. In the transmission side apparatus, an appropriate modulation scheme or the like for each subcarrier is determined using the transmission path estimation result.

  Since the receiving side device does not know which phase vector is held by the incoming signal transmitted from the transmitting side device, reception processing is performed using the assumed phase vector. At this time, the carrier detector 48 detects the carrier while switching the phase vector of the anti-phase rotator 45 by the control unit 47 in accordance with the version information of the packet assumed to be used.

  FIG. 12 is a flowchart illustrating operations of carrier detection and reception processing in the reception-side apparatus according to the first embodiment. Here, an operation assuming a case where packets of different versions coexist in the same communication method is shown. In the transmission side device, the phase vector to be used (phase vector A or B) is set in accordance with the version information corresponding to the version of the packet to be transmitted, and the transmission data is transmitted. Here, when determining the phase vector corresponding to the version information, a predetermined phase vector is set according to what is set in advance by the own device or setting operation, etc., and is set according to the phase vector of the data transmitted by the other device It is possible to use various methods such as setting according to a control signal or data transmitted from a host device such as a parent device. In addition, when a plurality of versions of phase vectors are detected in the data from other devices, they are set according to the old version or the phase vector of the communication system. Or you may set according to the phase vector of the newest version or communication system which an own apparatus can receive.

  In the receiving-side apparatus, first, the control unit 47 sets the phase vector A (first phase vector), and gives the preamble by giving the phase vector of version A (first version) by the anti-phase rotator 45. Search and perform carrier detection. Then, when the phase vector A is used, the control unit 47 determines whether the carrier detection is successful in the carrier detector 48 (step S11).

  Here, when the carrier detection is successful by the phase vector A, the carrier detector 48 notifies the carrier detection by the phase vector A to the demodulation processing unit including the equalizer 50, the demodulator 51, and the like (step S12). Then, the demodulation processing unit performs demodulation processing in accordance with the specification of the version information corresponding to the phase vector A (step S13). At this time, frame control, payload modulation method, used error correction method, used relative transmission power, etc. are determined according to the detected phase vector type, and demodulation processing conforming to the specification of version information is performed. .

  If the carrier cannot be detected by the phase vector A, the control unit 47 determines whether a predetermined time has elapsed, waits for a predetermined time (step S14), and sets the phase vector to the phase vector B (second phase vector). ) Is output to the anti-phase rotator 45. As a result, by providing the phase vector of version B (second version) by the antiphase rotator 45, the preamble is searched for carrier detection. Then, when the phase vector B is used, the control unit 47 determines whether the carrier detection is successful in the carrier detector 48 (step S15).

  Here, when the carrier detection is successful by the phase vector B, the carrier detector 48 notifies the demodulation processing unit including the equalizer 50, the demodulator 51 and the like of the carrier detection by the phase vector B (step S16). Then, the demodulation processing unit performs a demodulation process according to the specification of the version information corresponding to the phase vector B (step S17).

Specific examples of the version information assigned corresponding to each phase vector and the frame structure, modulation scheme, parameters, etc. of the communication system of this version information include the following.
(1) Phase vector A ... version 1, frame control: modulation (QPSK), FEC (convolutional code (coding rate (1/2))), transmission power, payload: modulation (BPSK to 256QAM), FEC (folding) (2) Phase vector B ... Version 2, frame control: modulation (QPSK), FEC (LDPC code (coding rate (1 / 2))), transmission power, payload: modulation (BPSK to 1024QAM), FEC (LDPC code (coding rate (1/2, 3/4, 7/8))), relative power, etc. Indicates the power ratio in the case where a difference in power is provided in accordance with the characteristics of the signal in the packet. For example, the magnitude relationship of the relative power in the packet is set as preamble <payload <frame control. This relative power is used when setting the power of each part in the packet so that the radiation power of the entire packet becomes constant.

  As described above, the receiving-side apparatus can determine the type of the phase vector of the transmitted packet by setting a specific phase vector and performing carrier detection of a signal corresponding to the phase vector. Then, the received packet can be correctly demodulated by performing demodulation processing conforming to the specification of the corresponding version information in the demodulation processing unit in accordance with the type of detected phase vector.

  In the first embodiment, carrier detection processing is not performed for a plurality of phase vectors at the same time, but carrier detection for each phase vector is performed using a fixed time one by one. Here, as the fixed time, for example, one period (one beacon period) set in the communication system such as one second is used. By performing carrier detection of a plurality of phase vectors at regular intervals, the circuit load can be reduced and the circuit scale can be reduced as compared with simultaneous processing. Note that the above processing may be performed when the device itself or another device is registered in the network for the first time, or using idle time.

  Next, an operation related to detection of a preamble using a phase vector will be described. First, an example of signal points on the complex plane of transmission data and reception data is shown. FIG. 13 is a diagram illustrating an example of signal points on a complex plane of transmission data. 14 and 15 are diagrams showing examples of signal points on the complex plane of received data. FIG. 14 shows a case where symbol synchronization is achieved and FIG. 15 shows a case where symbol synchronization is not achieved. . Here, the case where the bit string of the phase vector is composed of “0” and “π” will be described.

  Assume that the transmission side apparatus transmits all “1” transmission data as a preamble. In this case, as shown on the left side of FIG. 13, the output of the symbol mapper 31 is a series of symbols corresponding to “1”, and a plurality of signal points are concentrated on one point on the I axis of the complex plane. Then, the phase is rotated by 0 or π by the phase rotator 33 to give a phase vector. In this case, the output of the phase rotator 33 is a symbol corresponding to “1” or “−1” as shown on the right side of FIG. 13, and the signal point is at two points with the origin on the I axis of the complex plane. It will be gathered.

  In the receiving-side device that receives the transmission data, the output of the FFT converter 44 is as shown on the left side of FIG. 14 or FIG. Then, when the phase vector is restored by reversely rotating the phase by 0 or π by the antiphase rotator 45, the output is as shown on the right side of FIG. That is, when symbol synchronization is established, as shown on the left side of FIG. 14, the output of the FFT converter 44 is a collection of signal points at two points on the I axis of the complex plane with the origin in between. Then, the output of the anti-phase rotator 45 is such that the signal points are concentrated on one point on the I axis of the complex plane by returning the phase vector, and the symbol corresponding to “1” is restored. On the other hand, when symbol synchronization is not achieved, as shown on the left side of FIG. 15, the output of the FFT converter 44 is such that the signal points are not concentrated on one point on the complex plane, and the phase is randomly rotated and the origin is centered. It will be located on the circumference. Then, even if the phase vector is restored, the output of the anti-phase rotator 45 is the signal point located on the complex plane in a circular shape around the origin and randomly rotated in phase.

  Here, the configuration and operation of the carrier detector 48 used in the present embodiment will be described. FIG. 16 is a block diagram showing a configuration example of the carrier detector of this embodiment, and FIG. 17 is a diagram showing an example of signal points on the complex plane in the carrier detector of this embodiment. The carrier detector 48 includes a delay unit 121, an inter-carrier correlator 122, a correlation distribution calculator 123, and a comparison / determination unit 124. The inter-carrier correlator 122 compares the input data and the data delayed by the delay unit 121 to obtain the correlation between the carriers. For example, the inter-carrier correlator 122 calculates the inter-carrier correlation value C (n, k) by the following equation (1). In addition, since the correlation between carriers should just be calculated | required, it is not limited to following formula (1), For example, you may replace a complex conjugate symbol between d (n, k) and d (n, k-1). .

C (n, k) = d (n, k−1) × d (n, k) ^* (1)
Where C: correlation value between carriers
d: Complex value after FFT
n: OFDM symbol number
k: OFDM carrier number
^* : Complex conjugate

  When the same continuous data such as a preamble is transmitted using an OFDM multicarrier signal, the waveform of the transmission signal is a sine wave group in which each subcarrier is a sine wave. In this case, the phase difference between two adjacent subcarriers is constant for all subcarriers. Therefore, when the correlation between carriers is obtained, a constant value is obtained for all subcarriers. That is, in the preamble, the inter-carrier correlation value C (n, k) according to the equation (1) is a certain value regardless of whether synchronization is established.

  When the symbol synchronization is not established, the input of the carrier detector 48 is positioned on a circle centered on the origin on the complex plane with the phase rotated randomly as shown on the left side of FIG. It will be a thing. In contrast, the output of the inter-carrier correlator 122 is such that signal points are concentrated at a certain point on the complex plane as shown on the right side of FIG. 17 even if symbol synchronization is not achieved. Therefore, by determining whether or not the signal points of the output of the inter-carrier correlator 122 are concentrated at any point on the complex plane, it is possible to determine the presence or absence of the preamble, that is, to detect the carrier.

  The correlation distribution calculator 123 calculates the distribution on the complex plane of the output of the intercarrier correlator 122. The comparison / determination unit 124 compares and determines the output value of the correlation distribution calculator 123 with a predetermined threshold value, and outputs a determination result. For example, the correlation distribution calculator 123 divides the complex plane into a plurality of regions such as quadrants, obtains the number of signal points existing in each region, and calculates the maximum value thereof. Here, when the number of signal points existing in any region on the complex plane exceeds a predetermined value, it can be determined that signal points of inter-carrier correlation values are concentrated in the region. Therefore, the comparison / determination unit 124 determines whether or not there is a carrier by determining whether the output of the correlation distribution computing unit 123 exceeds the threshold value. The determination result of the comparison / determination unit 124 is output as a carrier detection signal of the carrier detector 48.

  FIG. 18 is a block diagram showing a first example of the configuration of the correlation distribution computing unit used in this embodiment. FIG. 19 is a diagram showing signal point regions on the complex plane to be counted in the correlation distribution calculator of FIG. The correlation distribution calculator 123A of the first example includes two code determination units 131A and 131B, four counters 132A, 132B, 132C, and 132D, and a maximum value detector 133.

  Correlation distribution computing unit 123A performs sign determination on in-phase component (I signal component) of input complex signal by sign determination unit 131A and sign determination of quadrature component (Q signal component) by sign determination unit 131B. Then, the counters 132A to 132D count the number of positive and negative signal points respectively output from the sign determiners 131A and 131B. As a result, as shown in FIG. 19, the number of carriers present in each quadrant of the first quadrant to the fourth quadrant on the complex plane is counted as a distribution on the complex plane of the output of the inter-carrier correlator 122. . When the counting for all the subcarriers is completed, the maximum value detector 133 detects and outputs the maximum value of the count values of the counters 132A to 132D.

  When the count value of any one of the counters 132A to 132D is large and the maximum value output from the maximum value detector 133 exceeds a predetermined value, the signal point of the output from the inter-carrier correlator 122 is on the complex plane. It is thought that it is concentrated in either area. Here, in the comparison / determination unit 124 of the carrier detector 48, for example, the threshold value is set to 0.75, and the count number of carriers existing in a specific quadrant on the complex plane in the total number of used carriers of the multicarrier signal (that is, The ratio of the maximum value of the output of the correlation distribution calculator 123) is compared with a threshold value. At this time, threshold value <(count number / total number of used carriers), and if the threshold value is exceeded, it is determined that a carrier has been detected.

  FIG. 20 is a block diagram showing a second example of the configuration of the correlation distribution calculator used in the present embodiment. FIG. 21 is a diagram showing signal point areas on the complex plane to be counted in the correlation distribution calculator of FIG. The correlation distribution calculator 123B of the second example includes a phase rotator 145, four sign determiners 141A, 141B, 141C, 141D, eight counters 142A, 142B, 142C, 142D, 142E, 142F, 142G, 142H, And a maximum value detector 143.

  The correlation distribution computing unit 123B performs sign determination on the in-phase component of the input complex signal by the code determination unit 141A, and code determination of the quadrature component by the code determination unit 141B, and rotates the phase of the complex signal by π / 4. The in-phase component of the generated signal is subjected to sign determination by the code determination unit 141C, and the quadrature component is subjected to code determination by the code determination unit 141D. Then, the counters 142A to 142H count the number of positive and negative signal points respectively output from the sign determiners 141A to 141D. Thus, as shown in FIG. 21, in addition to counting the number of carriers existing in each quadrant of the first quadrant to the fourth quadrant on the complex plane, the IQ axis of the complex plane is rotated by π / 4 (45 °). The number of carriers existing in a region corresponding to each quadrant in the state (each quadrant obtained by rotating each signal point on the complex plane by π / 4) is counted in parallel. In the case of the second example, the distribution on the complex plane of the output of the inter-carrier correlator 122 can be detected more precisely, and erroneous detection can be reduced, so that the maximum value detection accuracy in the maximum value detector 143 is improved. Can do. Thereby, the carrier detection accuracy of the carrier detector 48 can be improved.

(Second Embodiment)
FIG. 22 is a block diagram showing a configuration of a transmission side apparatus according to the second embodiment of the present invention. FIG. 22 illustrates a configuration example of a main part of a communication device that is a transmission-side device in the second embodiment. In this configuration example, inverse wavelet transform (IDWT) is used to modulate a multicarrier signal. The transmission side device includes a symbol mapper 31, an S / P converter 32, a phase rotator 233, an inverse wavelet converter 234, a P / S converter 35, a D / A converter 36, and a control unit 237. The In the following embodiments, portions different from those of the first embodiment will be mainly described, and description of similar configurations and operations will be omitted.

  The phase rotator 233 rotates the phase of the parallel data corresponding to each subcarrier according to the control signal from the control unit 237. When the inverse wavelet transform is used, complex information is configured by a subcarrier pair formed by a pair of two adjacent subcarriers. In FIG. 22, two signal lines surrounded by an ellipse indicate each subcarrier pair. Therefore, the 2n-1th input (n is a positive integer) is an in-phase component of complex information, the 2nth input is an orthogonal component of complex information (where 1 ≦ n ≦ M / 2-1), and the subcarrier number is Assuming 0 to M-1, complex subcarriers are composed of subcarrier pairs, and the phase of each subcarrier pair is rotated as in the case of using the inverse Fourier transform. That is, the phase is rotated by giving a phase rotation angle of, for example, “0” or “π” for each subcarrier pair. Here, the number of parallel data subjected to phase rotation is a maximum of M / 2-1, unlike the case of using inverse Fourier transform.

  The inverse wavelet transformer 234 performs IDWT of the phase-rotated parallel data and converts it into the frequency domain. In the inverse wavelet transformer 234, the parallel data of each subcarrier whose phase is rotated is subjected to inverse wavelet transform to perform multicarrier modulation to generate a multicarrier transmission signal. Note that the order of the symbol mapper 31 and the S / P converter 32 can be changed.

  The control unit 237 is responsible for the operation of the entire transmission-side apparatus and control of transmission data, and supplies a control signal to the phase rotator 233 to control setting and changing of the phase vector. Specifically, the control unit 237 controls the phase rotation operation in the phase rotator 233 based on the transmission timing of the preamble of the transmission data, and gives a specific phase vector to the transmission data. For example, as in the first embodiment, the control unit 237 uses a specific cyclic sequence using a specific bit sequence based on a pseudo-random value having two values of “0” and “π” based on the PN sequence. Generate a bit sequence by quantity. Then, the control unit 237 supplies the bit series as a phase vector control signal to the phase rotator 233 to rotate the phase for each target subcarrier pair, thereby setting a predetermined phase vector. At this time, the control unit 237 sets the assigned phase vector in accordance with version information for identifying the communication method, version, signal type and the like of the packet to be transmitted, and switches the phase vector of the phase rotator 233.

  FIG. 23 is a block diagram showing a configuration of a receiving side apparatus according to the second embodiment of the present invention. FIG. 24 is a block diagram showing a configuration of a part related to the phase vector of the receiving-side apparatus according to the second embodiment. FIG. 23 and FIG. 24 show an example of the configuration of the main part of a communication device that is a receiving-side device in the second embodiment. In this configuration example, wavelet transform (DWT) is used for demodulating a multicarrier signal. The receiving side device includes an AGC circuit 41, an A / D converter 42, an S / P converter 43, a wavelet converter 244, an antiphase rotator 245, a P / S converter 46, a control unit 247, a carrier detector 48, A synchronization circuit 49, an equalizer 50, a demodulator 51, and a transmission path estimator 52 are included.

  The wavelet transformer 244 performs DWT of parallel data and converts it into the time domain. In this wavelet transformer 244, parallel data of each subcarrier is wavelet transformed to perform multicarrier demodulation, and parallel data reception data corresponding to each subcarrier of the multicarrier signal is generated.

  The inverse phase rotator 245 rotates the phase of the parallel data corresponding to each subcarrier according to the control signal from the control unit 247, and restores the phase of each data. In FIG. 24, two signal lines surrounded by an ellipse indicate each subcarrier pair. Here, the number of parallel data subjected to phase rotation is maximum M / 2-1 unlike the case of using Fourier transform. Even if the order of the antiphase rotator 245 and the P / S converter 46 is changed, there is no problem in the operation.

  The control unit 247 controls the operation of the entire receiving-side apparatus, supplies a control signal to the antiphase rotator 245, and controls setting and changing of the phase vector to be restored. Specifically, the control unit 247 controls the phase rotation operation in the antiphase rotator 245, and restores the phase rotation of the data of each subcarrier by a specific phase vector. For example, as in the first embodiment, the control unit 247 uses a specific bit sequence based on a pseudo-random value having two values of “0” and “π” based on the PN sequence, and performs a specific cyclic shift. Generate a bit sequence by quantity. Then, the control unit 247 supplies the bit sequence as a phase vector control signal to the antiphase rotator 245 to rotate the phase for each target subcarrier. In this case, the phase vector control signal has the opposite sign to that of the transmission side apparatus. Thereby, the phase of the data of each subcarrier is restored by the set predetermined phase vector. At this time, the control unit 247 sets the phase vector assigned corresponding to the version information such as the communication method, version, and signal type of the received packet assumed to be used. For example, the phase vector of the antiphase rotator 245 is switched in accordance with a plurality of phase vectors corresponding to the version information that is expected to be transmitted.

  As described above, even in a configuration using wavelet transform instead of FFT, similarly to the first embodiment, the receiving-side apparatus can determine the version information of the transmission packet by determining the preamble phase vector. Therefore, the receiving side apparatus can perform an appropriate demodulation process according to the version information based on the detected phase vector.

(Third embodiment)
FIG. 25 is a block diagram showing a configuration of a receiving side apparatus according to the third embodiment of the present invention. The third embodiment shows a configuration in which carrier detection using a plurality of phase vectors is performed in parallel in a receiving side apparatus. The receiving side device includes an AGC circuit 41, an A / D converter 42, an S / P converter 43, an FFT converter 44, an antiphase rotator 345A, an antiphase rotator 345B, a P / S converter 346A, and a P / S. It includes a converter 346B, a control unit 347, a carrier detector 348A, a carrier detector 348B, a selector 355, a synchronization circuit 49, an equalizer 50, and a demodulator 51. The system of the anti-phase rotator 345A, P / S converter 346A, carrier detector 348A and the system of the anti-phase rotator 345B, P / S converter 346B, carrier detector 348B are the output side of the FFT converter 44. Are provided in parallel. The output units of the P / S converter 346A and the carrier detector 348A and the output units of the P / S converter 346B and the carrier detector 348B are connected to the input unit of the selector 355, and the output unit of the selector 355 is the synchronization circuit 49. And is connected to the equalizer 50.

  In addition, although the structural example provided with the FFT converter was shown in FIG. 25, it can apply similarly as a structure provided with a wavelet transformer instead.

  The anti-phase rotator 345A sets the phase vector A according to the control signal from the control unit 347 and rotates the phase of the parallel data corresponding to each subcarrier. The P / S converter 346A receives parallel data corresponding to each subcarrier of the multicarrier signal output from the antiphase rotator 345A and converts it into serial data. Note that the order of the antiphase rotator 345A and the P / S converter 346A may be switched.

  The anti-phase rotator 345B sets the phase vector B according to the control signal from the control unit 347 and rotates the phase of the parallel data corresponding to each subcarrier. The P / S converter 346B receives parallel data corresponding to each subcarrier of the multicarrier signal output from the antiphase rotator 345B and converts it into serial data. The order of the antiphase rotator 345B and the P / S converter 346B may be switched.

  The controller 347 outputs a control signal for setting the preamble phase vector A to the anti-phase rotator 345A. The control unit 347 outputs a control signal for setting the preamble phase vector B to the antiphase rotator 345B.

  The carrier detector 348A and the carrier detector 348B have the same configuration and function as the carrier detector 48 of FIG. The carrier detector 348A receives the reception data whose phase is restored by using the phase vector A by the antiphase rotator 345A, performs carrier detection, and detects the presence or absence of a preamble. The carrier detector 348B receives the reception data whose phase is restored by using the phase vector B by the anti-phase rotator 345B, detects the presence of a preamble by performing carrier detection. Carrier detection signals output from the carrier detector 348A and the carrier detector 348B are input to the selector 355 and used for switching signal paths. The selector 355 outputs phase vector information of the detected carrier to a demodulation processing unit including the synchronization circuit 49, the equalizer 50, and the like, and is used for demodulation processing. Here, it is assumed that the phase vector of the data part after the preamble is the same as the preamble.

  The selector 355 selectively switches the signal path based on the carrier detection signals from the carrier detector 348A and the carrier detector 348B, and receives data of the selected signal path, that is, the output of the P / S converter 346A and the P / S One of the outputs of the converter 346B is output to the synchronization circuit 49 and the equalizer 50. In the demodulation processing unit, the processing after synchronization performs demodulation processing using data coming from the selected signal path. Further, in processing after the preamble of the packet, specifically, frame control and payload, the demodulation method is selected according to the type of phase vector used for the selected signal path.

  Here, the carrier detector 348A and the carrier detector 348B operate in parallel, and the carrier detection process using the phase vector A and the carrier detection process using the phase vector B are performed in parallel. Since the carrier detector 348A and the carrier detector 348B have a simple configuration, even if they are provided in parallel, the circuit scale does not increase so much. When the carrier is correctly detected, a signal path using the corresponding phase vector is selected as a reception path by the selector 355.

  FIG. 26 is a flowchart illustrating a first example of carrier detection and reception processing operations in the reception-side apparatus according to the third embodiment. Here, an operation assuming a case where packets of different versions coexist in the same communication method is shown. In the transmission side device, the phase vector to be used (phase vector A or B) is set in accordance with the version information corresponding to the version of the packet to be transmitted, and the transmission data is transmitted. Here, when determining the phase vector corresponding to the version information, a predetermined phase vector is set according to what is set in advance by the own device or setting operation, etc., and is set according to the phase vector of the data transmitted by the other device It is possible to use various methods such as setting according to a control signal or data transmitted from a host device such as a parent device. In addition, when a plurality of versions of phase vectors are detected in the data from other devices, they are set according to the old version or the phase vector of the communication system. Or you may set according to the phase vector of the newest version or communication system which an own apparatus can receive.

  In the receiving apparatus, when carrier detection is started under the control of the control unit 347, the carrier detector 348A determines the presence / absence of a preamble based on the phase vector A, and in parallel, the carrier detector 348B determines the preamble based on the phase vector B. Presence / absence is determined. That is, the carrier detector 348A determines whether the carrier detection is successful using the phase vector A (step S21), and the carrier detector 348B determines whether the carrier detection is successful using the phase vector B. (Step S22). This carrier detection process is always operating. When a carrier is detected, a carrier detection signal is output to the selector 355 from the carrier detector that has been successfully detected.

  Here, when the carrier detection is successful using the phase vector A, the selector 355 selects the path A that is a signal path using the output of the P / S converter 346A, and the equalizer 50, the demodulator 51, and the like. Is notified that the path A has been selected (step S23). Then, the demodulation processing unit performs demodulation processing in accordance with the specification of the version information corresponding to the phase vector A (step S24).

  When carrier detection is successful using the phase vector B, the selector 355 selects the path B that is a signal path using the output of the P / S converter 346B, and the path B is selected by the demodulation processing unit. (Step S25). Then, the demodulation processing unit performs demodulation processing in accordance with the specification of the version information corresponding to the phase vector B (step S26).

  FIG. 27 is a flowchart illustrating a second example of carrier detection and reception processing operations in the reception-side apparatus according to the third embodiment. The second example shows processing when carrier detection is successful for both the phase vector A and the phase vector B. In this case, the carrier detector 348A uses the phase vector A to succeed in carrier detection, and the carrier detector 348B determines whether the carrier detection is successful using the phase vector B (step S31).

  Here, when carrier detection is successful in both the phase vector A and the phase vector B, since either detection result is a false detection, the selector 355 performs processing according to the previous detection result. That is, the selector 355 selects the signal path of the reception path by setting the previously detected phase vector as the correct one of the two detected phase vectors (step S32). Specifically, for example, when the previous phase vector A has been detected, it is determined that carrier detection has been performed by the phase vector A in this time as well, and the selection of the previously selected path A is notified to the demodulation processing unit.

  Depending on the transmission path environment, erroneous carrier detection may occur, and carrier detection may be performed simultaneously with a plurality of phase vectors. In such a case, it is preferable to determine that the phase vector on which carrier detection has been performed normally before is used, and to select the signal path of the corresponding phase vector. Note that statistical processing may be performed in advance to increase the reliability of the detection result reliability in each phase vector.

  As described above, according to the third embodiment, by performing carrier detection on a plurality of phase vectors in parallel at the receiving side apparatus, it is possible to determine the version information of the transmission packet based on the correctly detected phase vectors. Therefore, it is possible to change the specifications of all data after the preamble and the reception processing method corresponding to this, depending on the version or the like. For example, after the frame control, it is possible to change the specifications in each version to improve performance. Regarding the processing after frame control, even if the specifications are different for each version, it is not necessary to operate simultaneously corresponding to a plurality of versions, so that the circuit can be shared. In the case of the third embodiment, by performing carrier detection using a plurality of phase vectors at the same time, it is possible to determine the phase vector for each packet and recognize version information.

  In the above example, the case of two phase vectors has been described, but it is possible to deal with more phase vectors. In this case, as many carrier detection circuits as the number of phase vectors expected to be used (that is, the number of version information) may be prepared, and carrier detection may be performed in parallel using the respective phase vectors.

  Also, in the configuration of the third embodiment, carrier detection by a plurality of phase vectors is not performed simultaneously in parallel, and a plurality of phase vectors are alternately or one by one in time series as in the first embodiment. Carrier detection may be performed, and demodulation processing according to the specification of version information corresponding to the phase vector that has been successfully detected may be performed.

(Fourth embodiment)
The fourth embodiment shows a configuration example of a transmission side apparatus and a reception side apparatus when applied to a wireless communication apparatus that performs communication using a wireless line. FIG. 28 is a block diagram showing a configuration of a transmission side apparatus according to the fourth embodiment of the present invention. FIG. 29 is a block diagram showing a configuration of a reception-side apparatus according to the fourth embodiment of the present invention.

  The transmission side device includes a symbol mapper 631, an S / P converter 632, a phase rotator 633, an inverse FFT converter 634, a P / S converter 635, a D / A converter 636, a control unit 637, a wireless transmission unit 661, An antenna 662 is included. Here, the configurations and functions of the symbol mapper 631 to the D / A converter 636 and the control unit 637 are the same as those of the first embodiment shown in FIG.

  The wireless transmission unit 661 includes a transmission RF unit including an up-converter that converts a transmission signal to a radio frequency band, a power amplifier that amplifies the transmission signal, and the like. A transmission signal in the radio frequency band output from the wireless transmission unit 661 is radiated and transmitted as a radio wave from the antenna 662.

  The reception-side device includes an antenna 671, a wireless reception unit 672, an AGC circuit 641, an A / D converter 642, an S / P converter 643, an FFT converter 644, an antiphase rotator 645, a P / S converter 646, and a control. 647, carrier detector 648, synchronization circuit 649, equalizer 650, demodulator 651, and transmission path estimator 652. The configurations and functions of the AGC circuit 641 to the transmission path estimator 652 and the control unit 647 are the same as those in the first embodiment shown in FIG.

  The wireless reception unit 672 includes a reception RF unit including a down converter that converts a reception signal into a baseband band. A reception signal obtained by receiving a radio wave with the antenna 671 is converted into a baseband by the radio reception unit 672, and various reception processes are performed in a subsequent circuit.

  28 and 29 show the configuration example using the FFT / inverse FFT transform, but the present invention can be similarly applied to a configuration using wavelet transform / inverse wavelet transform instead.

  In this way, by applying the configuration of each embodiment described above in a communication device that uses a wireless line, a specific phase vector that differs depending on the communication method, version, signal type, and the like is set for the packet preamble in the transmission side device. Can be set and sent. The receiving side device can identify the version information embedded in the preamble by using the phase vector, and can perform demodulation processing according to the specification of the version information.

(Fifth embodiment)
The fifth embodiment shows a configuration example when applied to a power line communication apparatus that performs communication using a power line as a communication medium. FIG. 30 is a diagram showing a configuration of a power line communication system according to the fifth embodiment. 30 includes PLC modems 1100M, 1100T1, 1100T2, 1100T3,..., 1100TN, which are a plurality of communication devices connected to the power line 1350. FIG. 30 shows five PLC modems, but the number of connections is arbitrary. The PLC modem 1100M functions as a master unit, and manages the connection status (link status) of other PLC modems 1100T1,... 1100TN functioning as slave units. However, the PLC modem functioning as the master unit is not essential. In the following description, these PLC modems are collectively referred to as a PLC modem 1100.

  Although the power line 1350 is shown as one line in FIG. 30, it is actually two or more conductors, and the PLC modem 1100 is connected to two of them.

  31A and 31B are views showing the appearance of the PLC modem 1100. FIG. 31A is an external perspective view showing the front surface, FIG. 31B is a front view, and FIG. 31C is a rear view. A PLC modem 1100 shown in FIG. 31 has a housing 1101, and LEDs (Light Emitting Diodes) 1105 A, 1105 B, and 1105 C are provided on the front surface of the housing 1101 as shown in FIGS. A display unit 1105 is provided. Further, on the rear surface of the housing 1101, as shown in FIG. 31C, a power connector 1102, a modular jack for LAN (Local Area Network) 1103 such as RJ45, and a change-over switch 1104 for switching operation modes and the like. Is provided. A power cable (not shown in FIG. 31) is connected to the power connector 1102, and a LAN cable (not shown in FIG. 31) is connected to the modular jack 1103. The PLC modem 1100 may be further provided with a Dsub (D-subminiature) connector to connect a Dsub cable.

  FIG. 32 is a block diagram illustrating an example of a hardware configuration of the PLC modem 1100. The PLC modem 1100 includes a circuit module 1200 and a switching power supply 1300 as shown in FIG. The switching power supply 1300 supplies various voltages (for example, + 1.2V, + 3.3V, + 12V) to the circuit module 1200, and includes, for example, a switching transformer and a DC-DC converter (none of which are shown). Consists of.

  The circuit module 1200 includes a main IC (Integrated Circuit) 1210, an AFE IC (Analog Front End Integrated Circuit) 1220, an Ethernet (registered trademark) PHY IC (Physic layer Integrated Circuit) 1230, and a low pass filter. LPF) 1251, driver IC 1252, band pass filter (BPF) 1260, and coupler 1270 are provided. Switching power supply 1300 and coupler 1270 are connected to power connector 1102 and further connected to power line 1350 via power cable 1320, power plug 1330, and outlet 1340. The main IC 1210 functions as a control circuit that performs power line communication.

  The main IC 1210 includes a CPU (Central Processing Unit) 1211, a PLC-MAC (Power Line Communication / Media Access Control Layer) block 1212, and a PLC / PHY (Power Line Communication / Physical 13) block 13. The CPU 1211 is implemented with a 32-bit RISC (Reduced Instruction Set Computer) processor, for example. The PLC / MAC block 1212 manages the MAC layer (Media Access Control layer) of the transmission / reception signal, and the PLC / PHY block 1213 manages the PHY layer (Physical layer) of the transmission / reception signal. The AFE IC 1220 includes a DA converter (DAC) 1221, an AD converter (ADC) 1222, and a variable amplifier (VGA) 1223. The coupler 1270 includes a coil transformer 1271 and coupling capacitors 1272a and 1272b. The CPU 1211 controls the operation of the PLC / MAC block 1212 and the PLC / PHY block 1213 using the data stored in the memory 1240 and also controls the entire PLC modem 1100.

  The circuit module 1200 is provided with an AC cycle detector 1400. The AC cycle detector 1400 generates a synchronization signal necessary for each PLC modem to perform control at a common timing. As an example of the synchronization signal, a rectangular wave composed of a plurality of pulses synchronized with the zero cross point of the AC power waveform can be cited. The AC cycle detector 1400 includes a diode bridge 1401, resistors 1402 and 1403, a DC power supply unit 1405, and a capacitor 1404. The input side of one end of the diode bridge 1401 is connected in parallel with the switching power supply 1300 and the coupler 1270. The output side of the other end of the diode bridge 1401 is connected to the resistor 1402. The resistor 1402 is connected in series with the resistor 1403. Resistor 1402 and resistor 1403 are connected in parallel to one terminal of capacitor 1404. The DC power supply unit 1405 is connected to the other terminal of the capacitor 1404.

  Transmission of the transmission packet is performed as follows. The main IC 1210 is a zero-crossing point at which the AC power waveform AC of the commercial power source supplied to the power line 1350, that is, the voltage of the AC waveform composed of a 50 Hz or 60 Hz sine wave becomes zero based on the synchronization signal of the output of the AC cycle detector 1400. And the timing for transmitting the transmission packet is determined using the timing at which the zero cross point is detected and the value of the cycle of the commercial power supply.

  Since the cycle of the commercial power supply is stable with little fluctuation, using the commercial power cycle for the synchronization process between the communication devices has an advantage that the synchronization between the communication devices can be stably performed. In addition, noise and transmission path fluctuations occur in synchronization with the cycle of the commercial power supply on the power line, so if the timing and period at which noise and transmission path fluctuations occur can be predicted by transmission path estimation, the transmitted packet will collide with noise and transmission path fluctuations. It is possible to determine the transmission timing so that it does not occur. Here, transmission path estimation is a process for estimating the quality of a transmission path (power line) as a communication line. For example, noise generation timing and cycle prediction, transmission path fluctuation status, etc. are detected. To do.

  If transmission packets are transmitted in synchronization with the commercial power cycle, synchronization processing between communication devices can be performed without detecting a zero cross point. For example, it is possible to set a timing that is a reference for synchronization processing between communication devices, and to determine a timing for transmitting a transmission packet using the timing and a value of a cycle of a commercial power source.

  Communication by the PLC modem 1100 is generally performed as follows. Data input from the modular jack 1103 is sent to the main IC 1210 via the Ethernet (registered trademark) PHY IC 1230. A digital transmission signal is generated by performing digital signal processing in the main IC 1210. The generated digital transmission signal is converted to an analog signal by the DA converter (DAC) 1221 of the AFE / IC 1220, and the low-pass filter 1251, the driver IC 1252, the coupler 1270, the power connector 1102, the power cable 1320, the power plug 1330, and the outlet 1340. To the power line 1350.

  A signal received from the power line 1350 is sent to the band pass filter 1260 via the coupler 1270, and after gain adjustment is performed by the variable amplifier (VGA) 1223 of the AFE / IC 1220, the signal is digitally converted by the AD converter (ADC) 1222. Converted to a signal. The converted digital signal is sent to the main IC 1210, and is converted into digital data by performing digital signal processing in the main IC 1210. The converted digital data is output from the modular jack 1103 via the Ethernet (registered trademark) PHY IC 1230.

  The PLC modem 1100 performs multicarrier communication using a plurality of subcarriers based on the OFDM method, and digital signal processing related to communication signals is realized by the main IC 1210. Here, digital signal processing such as processing for converting transmission data into OFDM transmission signals, processing for converting OFDM reception signals into reception data, and carrier detection processing for detecting the presence or absence of transmitted OFDM signals are mainly performed by PLC / PHY blocks. At 1213.

  In the main IC 1210 of the PLC modem 1100 as described above, by applying the configuration of each of the above-described embodiments, a specific phase vector that differs depending on the communication method, version, signal type, etc. is set for the packet preamble on the transmitting side device Can be sent. The receiving side device can identify the version information embedded in the preamble by using the phase vector, and can perform demodulation processing according to the specification of the version information.

  As described above, in this embodiment, when transmitting a packet including communication data, a different phase vector is associated with each version information having a different packet communication method, version, signal type, etc., and used in the preamble. Give the phase vector of version information. By performing carrier detection using a specific phase vector, the receiving side device can determine the phase vector being used, and can perform reception processing in accordance with version information corresponding to this phase vector. For this reason, the frame control and the like after the preamble can be changed in specifications for each version and signal type while ensuring compatibility, so that the function and performance can be improved by updating the version.

  The present invention is intended to be variously modified and applied by those skilled in the art based on the description in the specification and well-known techniques without departing from the spirit and scope of the present invention. Included in the scope for protection.

  The present invention has an effect that the specification can be changed depending on the packet communication method, version, signal type, etc., including the part where the control information of the packet to be transmitted is stored, the packet communication method, version by the packet preamble, etc. It has the effect of making it possible to discriminate the signal type and the like, and is useful as a communication device capable of multi-carrier communication such as an OFDM method, such as a power line communication device and a wireless communication device.

101 Preamble 102 Frame control (FC)
103 Payload 10 Transmitter 11 Multi-Carrier Modulator 12 D / A Converter 13 Analog Front End (AFE)
14 Coupler 15 Phase Vector Setting Unit 16 Transmission Line 20 Receiving Device 21 Coupler 22 Analog Front End (AFE)
23 A / D converter 24 Multi-carrier demodulator 25 Phase vector restoration unit 31, 631 Symbol mapper 32, 632 Serial / parallel converter (S / P converter)
33, 233, 633 Phase rotator 34, 634 Inverse FFT converter 35, 635 Parallel / serial converter (P / S converter)
36, 636 D / A converter 37, 237, 637 Control unit 41, 641 AGC circuit 42, 642 A / D converter 43, 643 S / P converter 44, 644 FFT converter 45, 245, 345A, 345B, 645 Anti-phase rotator 46, 346A, 346B, 646 P / S converter 47, 247, 347, 647 Control unit 48, 348A, 348B, 648 Carrier detector 49, 649 Synchronization circuit 50, 650 Equalizer 51, 651 Demodulator 52, 652 Transmission path estimator 121 Delay unit 122 Inter-carrier correlator 123, 123A, 123B Correlation distribution calculator 124 Comparison determination unit 131A, 131B, 141A, 141B, 141C, 141D Code determination unit 132A, 132B, 132C, 132D, 142A, 142B, 142C, 142D, 1 2E, 142F, 142G, 142H Counter 133, 143 Maximum value detector 145 Phase rotator 234 Inverse wavelet transformer 244 Wavelet transformer 355 Selector 661 Radio transmitter 662 Antenna 671 Antenna 672 Radio receiver 1100, 1100M, 1100T1, 1100T2, 1100T3, 1100TN PLC modem 1101 Housing 1102 Power connector 1103 Modular jack 1104 Changeover switch 1105 Display unit 1200 Circuit module 1210 Main IC
1211 CPU
1212 PLC / MAC block 1213 PLC / PHY block 1220 AFE / IC
1221 DA converter (DAC)
1222 AD converter (ADC)
1223 Variable Amplifier (VGA)
1230 Ethernet PHY IC
1251 Low-pass filter (LPF)
1252 Driver IC
1260 Band pass filter (BPF)
1270 Coupler 1271 Coil transformer 1272a, 1272b Coupling capacitor 1300 Switching power supply 1320 Power cable 1330 Power plug 1340 Outlet 1350 Power line 1400 AC cycle detector

Claims (23)

A communication device that includes a plurality of data and transmits transmission data having a preamble,
A phase vector setting unit that rotates a phase for at least one of the plurality of data and sets a phase vector for the transmission data;
A multi-carrier modulation unit that performs multi-carrier modulation based on a predetermined communication scheme for transmission data in which a phase vector is set by the phase vector setting unit, and generates a transmission signal including a plurality of subcarriers,
The phase vector setting unit is a communication device that sets a phase vector corresponding to the predetermined communication method for data corresponding to the preamble among the plurality of data. The communication device according to claim 1,
A control unit for controlling a phase vector set by the phase vector setting unit according to a transmission timing of the preamble;
The phase vector setting unit is a communication device that switches to a phase vector corresponding to the predetermined communication method based on the control of the control unit. The communication device according to claim 2,
The communication device communicates with a first other communication device that performs communication processing based on the first communication method and a second other communication device that performs communication processing based on the second communication method,
The multicarrier modulation unit performs multicarrier modulation based on the first communication method or the second communication method,
The control unit notifies the phase vector setting unit of first control information based on a transmission timing of a preamble of a first transmission packet addressed to the first other communication device, and the second other communication Notifying the phase vector setting unit of the second control information based on the transmission timing of the preamble of the second transmission packet addressed to the device,
The phase vector setting unit sets a first phase vector corresponding to the first communication scheme in a preamble of the first transmission packet based on the first control information and the second control information. A communication device that sets a second phase vector corresponding to the second communication method in a preamble of the second packet. The communication device according to claim 3,
The communication apparatus in which the first communication method is a communication method using wavelet OFDM, and the second communication method is a communication method using OFDM. The communication device according to claim 3,
The first communication method is a first version of the predetermined communication method, and the second communication method is a second version of the predetermined communication method. The communication device according to any one of claims 1 to 5,
The control unit is a communication device that determines the phase vector by a cyclic shift type bit sequence. The communication device according to any one of claims 1 to 6,
The phase vector setting unit is a communication device that sets a phase vector of transmission data of its own device in accordance with a phase vector of data transmitted by another communication device. The communication device according to any one of claims 1 to 7,
The phase vector setting unit is a communication device that sets a phase vector of transmission data of its own device in accordance with a control signal or data transmitted from a host device of the network. The communication device according to any one of claims 1 to 8,
When the phase vector setting unit detects a plurality of phase vectors in data transmitted by another device, the phase vector setting unit sets a phase vector of transmission data of the own device in accordance with a phase vector of an old version or a communication method. The communication device according to any one of claims 1 to 9,
The multi-carrier modulation unit is a communication device configured to include an inverse FFT converter that performs multi-carrier modulation using inverse Fourier transform. The communication device according to any one of claims 1 to 9,
The multicarrier modulation unit is a communication device configured to include an inverse wavelet transformer that performs multicarrier modulation using inverse wavelet transform. A receiver for receiving a transmission signal composed of a plurality of subcarriers;
A multicarrier demodulator that acquires received data by performing multicarrier demodulation based on a predetermined communication method for the transmission signal;
A phase vector restoration unit that restores the phase of the received data by reverse rotation using a phase vector;
A carrier detection unit that performs carrier detection on the reception data whose phase is reversely rotated by the phase vector restoration unit, and determines a preamble of the reception data;
A demodulation processing unit that performs demodulation processing of the received data,
The phase vector restoration unit restores the phase of the received data using a phase vector corresponding to the predetermined communication method,
The demodulation processing unit is a communication device that performs demodulation processing based on the predetermined communication method. The communication device according to claim 12,
A control unit that controls the phase vector used by the phase vector restoration unit based on the predetermined communication method;
The communication device that switches the phase vector restoration unit to a phase vector corresponding to the predetermined communication method based on the control of the control unit. The communication device according to claim 13,
The receiving unit receives a first transmission signal from a first other communication device that performs communication processing based on a first communication method, and performs a second processing that performs communication processing based on a second communication method. Receiving the second transmission signal from the communication device of
The multi-carrier demodulator performs multi-carrier demodulation of the first transmission signal based on the first communication scheme to obtain first reception data, and the second carrier scheme based on the second communication scheme. The second received data is obtained by performing multicarrier demodulation of the received data of
The controller switches the third control information corresponding to the first transmission signal and the fourth control information corresponding to the second transmission signal to notify the phase vector restoration unit,
The phase vector restoration unit, based on the third control information and the fourth control information, a first phase vector corresponding to the first communication method and a second phase corresponding to the second communication method. A communication device that switches the phase vector of the first and second phases to restore the phase of the first received data and the second received data. 15. The communication device according to claim 14, wherein
The control unit notifies the phase vector restoration unit of the third control information and the fourth control information in time series,
The phase vector restoration unit switches the first phase vector and the second phase vector in time series,
The carrier detection unit is a communication device that performs carrier detection using the first phase vector and carrier detection using the second phase vector in time series. The communication device according to any one of claims 14 to 15,
The communication apparatus in which the first communication method is a communication method using wavelet OFDM, and the second communication method is a communication method using OFDM. The communication device according to any one of claims 14 to 15,
The first communication method is a first version of the predetermined communication method, and the second communication method is a second version of the predetermined communication method. The communication device according to any one of claims 14 to 17,
The phase vector restoration unit uses a first phase rotator that rotates a phase using a first phase vector corresponding to the first communication method, and a second phase vector corresponding to the second communication method. And a second phase rotator for rotating the phase
The carrier detection unit is a communication device that performs carrier detection using the first phase vector and carrier detection using the second phase vector in parallel. A communication device according to claim 12-18,
When the carrier detection unit succeeds in carrier detection using a plurality of phase vectors in the carrier detection unit, the demodulation unit selects a phase vector that has been successfully detected before, and performs demodulation processing based on a communication method corresponding to the phase vector Communication device that performs. The communication device according to claim 12-19,
The multicarrier demodulation unit is a communication device configured to include an FFT converter that performs multicarrier demodulation using Fourier transform. The communication device according to claim 12-19,
The multicarrier demodulator is a communication device configured to include a wavelet transformer that performs multicarrier demodulation using wavelet transform. The communication device according to any one of claims 1 to 21,
A communication device in which a transmission line for data communication is a power line. The communication device according to any one of claims 1 to 21,
A communication device in which a transmission line for data communication is a wireless line.

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