JP5910239B2 - COMMUNICATION DEVICE, COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to a communication device, a communication system, a communication method, and a program.

When communication is performed in a propagation environment in which a preceding wave and a delayed wave exist, a notch in which received power is reduced due to interference between the preceding wave and the delayed wave may occur. Several techniques have been proposed as countermeasures against such notches.
For example, in a wireless communication system based on orthogonal frequency division multiplexing described in Patent Document 1, a notch portion is estimated and communication is performed while avoiding the estimated notch portion.

JP 2003-333013 A

  However, the radio communication system based on orthogonal frequency division multiplexing described in Patent Document 1 requires a device for evaluating the position and movement of the zero point of the channel transfer function, and the apparatus configuration becomes complicated.

  An object of this invention is to provide the communication apparatus, communication system, communication method, and program which can solve the above-mentioned subject.

The present invention has been made to solve the above-described problem, and a communication device according to an aspect of the present invention includes a modulation unit that modulates and transmits a plurality of signals using the same number or more frequencies as the number of signals, A frequency allocation unit that allocates each of the plurality of signals to the frequency, and the frequency allocation unit has a first M sequence and the same period as the first M sequence, and a code length of each code is The second M sequence having the same code length as the code of the first M sequence and a different type of M sequence from the first M sequence, and the initial values of the second M sequence are changed. The plurality of signals are respectively assigned to the frequencies based on the same number of sequences as the number of transmission signals based on a bitwise exclusive OR with each of the one or more M sequences .

In addition, a communication device according to one aspect of the present invention includes a demodulation unit that receives a signal and demodulates the signal for each frequency, a first M sequence, and the same period as the first M sequence. A second M sequence having the same code length as the first M sequence and a different type of M sequence from the first M sequence, and an initial value of the second M sequence A frequency allocation detector for detecting correspondence between the frequency and communication data based on the same number of demodulated signals as a result of bitwise exclusive ORing with each of one or more M sequences that vary It is characterized by comprising.

In addition, a communication system according to an aspect of the present invention includes a first communication device and a second communication device, and the first communication device uses a frequency equal to or more than the number of signals for a plurality of signals. A modulation unit that modulates and transmits; and a frequency allocation unit that allocates each of the plurality of signals to the frequency. The frequency allocation unit has a first M sequence and a period that is the same as that of the first M sequence. A second M sequence having the same code length as the code of the first M sequence and a different M sequence from the first M sequence, and the second And assigning the plurality of signals to the frequency based on the same number of sequences as the number of transmission signals based on bitwise exclusive OR with each of one or more M sequences in which the initial value of the M sequence is changed The second communication device receives a signal and demodulates it for each frequency. , Based on the same sequence as the sequence in which the frequency allocation unit is used, characterized by comprising a frequency assignment detection unit for detecting a correspondence between the communication data with the frequency.

Further, the communication method according to one aspect of the present invention includes a modulation step of modulating and transmitting a plurality of signals using the same number or more frequencies as the number of signals, and a frequency allocation step of assigning the plurality of signals to the frequencies, respectively. In the frequency allocation step, the first M sequence has the same period as the first M sequence, and the code length of each code has the same code length as the code of the first M sequence. And for each bit of the second M sequence, which is a different type of M sequence from the first M sequence, and one or more M sequences in which the initial value of the second M sequence is changed. Each of the plurality of signals is assigned to the frequency based on the same number of sequences as the number of transmission signals based on the exclusive OR of .

In addition, a program according to an aspect of the present invention provides a computer that controls a communication apparatus including a modulation unit that modulates and transmits a plurality of signals using the same number or more frequencies as the number of signals. A frequency allocation step for allocating each frequency , wherein the first M sequence has the same period as the first M sequence, and the code length of each code is the first M sequence A second M sequence that has the same code length as the code and is a different type of M sequence from the first M sequence, and one or more Ms in which initial values of the second M sequence are changed This is a program for assigning each of the plurality of signals to the frequency based on the same number of sequences as the number of transmission signals , based on bitwise exclusive OR with each of the sequences .

  According to the present invention, the influence of the notch can be reduced with a simpler device configuration.

It is a schematic block diagram which shows the function structure of the communication system in one Embodiment of this invention. It is explanatory drawing which shows the example of the notch in the communication system of the embodiment. In the same embodiment, it is explanatory drawing which shows the example of the change of the transmission frequency which a frequency allocation part performs with respect to one transmission signal. In the embodiment, it is explanatory drawing which shows the example of the column vector based on M series which becomes the origin of the matrix which a frequency allocation part uses. In the same embodiment, it is explanatory drawing which shows the example of the matrix which a frequency allocation part uses. In the embodiment, it is explanatory drawing which shows the example of the allocation of the transmission frequency which a frequency allocation part performs. In the embodiment, it is explanatory drawing which shows the example of the pattern of the signal which a communication apparatus transmits. FIG. 4 is an explanatory diagram illustrating a procedure of processing performed by the communication system in the embodiment. It is a schematic block diagram which shows the minimum structure of this invention in the communication apparatus of the embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing a functional configuration of a communication system according to an embodiment of the present invention. In FIG. 1, the communication system 1 includes a communication device (first communication device) 100 and a communication device (second communication device) 200. The communication apparatus 100 includes an error correction coding unit 111, an interleaver 112, a frequency setting unit 121, a frequency allocation unit 122, a pilot signal generation unit 131, a modulation unit 141, and an antenna 151. The communication apparatus 200 includes an antenna 211, a frequency characteristic measurement unit 221, a frequency pattern calculation unit 222, a frequency setting unit 223, a frequency assignment detection unit 224, a demodulation unit 231, a de-interleaver 232, and error correction decoding. Part 233.

The communication device 100 transmits a radio signal using a plurality of frequencies (transmission frequencies). For example, the communication device 100 is a wireless transmission device, receives communication data of a plurality of users, sets a transmission frequency for each user, and wirelessly transmits the communication data using the set transmission frequency.
Error correction coding section 111 performs error correction coding on each of the plurality of communication data, and outputs the result to interleaver 112. Here, the error correction encoding unit 111 acquires (receives) communication data from an external device, for example.

  The interleaver 112 performs division and rearrangement (interleave) on each of the error correction encoded communication data from the error correction encoding unit 111. This is because when noise is mixed in the communication data, it is possible to avoid the concentration of code errors in a part and improve the decoding possibility. The interleaver 112 outputs the rearranged communication data to the modulation unit 141.

  The frequency setting unit 121 determines a transmission frequency used by the communication apparatus 100 and outputs information indicating the determined transmission frequency to the frequency allocation unit 122. In particular, the frequency setting unit 121 transmits within the range of the frequency displacement width (communication bandwidth) determined by the communication device 200 (frequency pattern calculation unit 222) based on the notch interval measured by the frequency response of the channel. The number of transmission frequencies corresponding to the number of signals is determined. For example, the frequency setting unit 121 receives a notification of the frequency displacement width and the number of transmission frequencies from the communication apparatus 200, and determines the transmission frequency by equally dividing the frequency displacement width by the number of the transmission frequencies.

  The frequency allocation unit 122 allocates a plurality of communication data (transmission signals) to the transmission frequency determined by the frequency setting unit 121. At that time, the frequency allocation unit 122 generates the number of numerical values corresponding to the number of transmission signals using the M-sequence, assigns a plurality of transmission signals to the transmission frequencies based on the numerical values, and periodically changes the allocation. To do. As will be described later, by performing the assignment using the M-sequence, the transmission signal can be randomly assigned to the transmission frequency, and it can be avoided that the same signal is continuously assigned to the frequency of the notch portion.

Further, the frequency allocating unit 122 generates the number of numerical values corresponding to the number of transmission signals by using the M series of the number of stages according to the number of transmission signals (the number of stages of the shift register that generates the M series). As described above, since the frequency allocating unit 122 uses the M series having the number of stages corresponding to the number of transmission signals, a transmission frequency having a scale corresponding to the number of transmission signals may be prepared. In other words, there is no need to ensure a useless transmission frequency.
Further, the frequency allocation unit 122 allocates the transmission signal to the transmission frequency determined by the frequency setting unit 121, and is included in the frequency displacement width calculated based on the interval of the notch portions measured by the frequency response of the channel. A plurality of transmission signals are assigned to transmission frequencies.
The frequency allocation unit 122 outputs information indicating the determined allocation to the modulation unit 141.

Pilot signal generating section 131 generates a pilot signal for propagation path condition measurement (a signal known by communication apparatus 200) and outputs the pilot signal to modulating section 141.
Modulation section 141 modulates the rearranged communication data from interleaver 112 into a signal of the transmission frequency determined by frequency setting section 121 according to the allocation determined by frequency allocation section 122 and transmits using antenna 151. That is, the modulation unit 141 modulates and transmits a plurality of signals using the same number or more frequencies as the number of signals. Moreover, the modulation | alteration part 141 inserts a pilot signal in a transmission signal regularly, for example, and transmits.
The antenna 151 transmits a communication signal (transmission signal) output as an electrical signal from the modulation unit 141 as a radio signal.

The communication device 200 receives the radio signal transmitted from the communication device 100 and restores each communication data. For example, the communication device 200 is a wireless transmission device, and transmits the restored communication data to each transmission destination.
The antenna 211 receives a signal transmitted as a radio signal from the communication apparatus 100 and outputs the signal to the frequency characteristic measurement unit 221 and the demodulation unit 231 as an electrical signal.

The frequency characteristic measurement unit 221 measures the frequency characteristic of the channel (transmission path) between the communication apparatus 100 and the communication apparatus 200 based on the pilot signal included in the communication signal (reception signal) received by the antenna 211, The measurement result is output to the frequency pattern calculation unit 222.
The frequency pattern calculation unit 222 determines the frequency displacement width used by the communication system 1 based on the frequency characteristics measured by the frequency characteristic measurement unit 221, and sets information indicating the determined frequency displacement width to the frequency setting unit 223 and the frequency setting unit. And 121. For example, wireless communication is performed from the communication device 200 to the communication device 100, and the frequency pattern calculation unit 222 outputs (transmits) information indicating the frequency displacement width to the frequency setting unit 121 as a wireless signal.
Instead of transmitting information from the frequency pattern calculation unit 222 to the communication device 100, both the communication device 100 and the communication device 200 may include a frequency pattern calculation unit to calculate the same frequency displacement width. .

The frequency setting unit 223 determines the same frequency as the frequency setting unit 121 based on the information from the frequency pattern calculation unit 222 (that is, detects the transmission frequency determined by the frequency setting unit 121), and determines the determined frequency. It outputs to the frequency allocation detection part 224.
The frequency allocation detection unit 224 detects the frequency allocation determined by the frequency allocation unit 122. More specifically, the frequency allocation detection unit 224 generates the number of numerical values corresponding to the number of signals demodulated by the demodulation unit 231 using the same M sequence as the frequency allocation unit 122, and based on the numerical values, And the communication data are associated with each other, thereby detecting the correspondence between the frequency determined by the frequency allocation unit 122 and the communication data. In particular, the frequency allocation detection unit 224 detects the correspondence relationship of communication data before and after the allocation change with respect to the periodic frequency allocation change performed by the frequency allocation unit 122.
The frequency allocation detection unit 224 outputs information indicating the detected correspondence relationship to the demodulation unit 231.

The demodulator 231 receives the signal and demodulates it for each frequency. More specifically, the demodulation unit 231 receives a signal from the communication device 100 via the antenna 211, demodulates the frequency component determined by the frequency setting unit 223 from the signal (reception signal), and transmits communication data. To extract. At that time, based on the frequency allocation detected by the frequency allocation detection unit 224, the demodulation unit 231 associates received signals before and after the frequency allocation change performed by the communication device 100 (frequency allocation unit 122) to obtain communication data. Extract. As a result, the demodulation unit 231 restores communication data at a stage where the error correction encoding unit 111 performs error correction encoding and the interleaver 112 performs rearrangement.
The demodulator 231 outputs the obtained communication data to the deinterleaver 232.

The de-interleaver 232 restores the communication data before being rearranged (error-correction coded) by performing the reverse sorting of the communication data by the interleaver 112 on the communication data from the demodulator 231. (De-interleave) and output to the error correction decoding unit 233.
The error correction decoding unit 233 performs error correction on the error correction encoded communication data from the de-interleaver 232 and restores the original communication data. The error correction decoding unit 233 outputs (transmits) the restored communication data to, for example, an external device.

Next, frequency allocation in the communication system 1 will be described with reference to FIGS.
FIG. 2 is an explanatory diagram illustrating an example of notches in the communication system 1.
When communication is performed in a propagation environment in which a preceding wave and a delayed wave exist, the channel impulse response h (t) can be expressed as in Equation (1).

Here, δ (t) represents a unit impulse function (Dirac delta function), and a preceding wave arrives at the communication apparatus 200 at time t = 0. Further, τ represents the delay time of the delayed wave, and ρ represents the amplitude of the delayed wave. E and j represent the Napier number and the imaginary unit, respectively, and θ represents the phase difference of the delayed wave with respect to the preceding wave.
This equation (1) is Fourier transformed, and the frequency response H (f) of the channel is expressed as equation (2).

That is, as shown in FIG. 2, notches are generated with a period of f = 1 / τ. At frequencies near this notch, the received power decreases and the received radio wave characteristics (for example, the signal-to-noise ratio (SNR)) deteriorate.
Therefore, the frequency assignment unit 122 periodically changes the transmission frequency assigned to each transmission signal.

FIG. 3 is an explanatory diagram illustrating an example of changing the transmission frequency performed by the frequency allocation unit 122 for one transmission signal. In the figure, a frequency allocation unit 122 allocates a frequency f13 to the transmission signal, then allocates a frequency f11, and then allocates a frequency f12. Thereafter, the frequency allocation unit 122 periodically changes the transmission frequency to be allocated.
As described above, it is possible to prevent deterioration in communication quality by periodically changing the transmission frequency assigned to each transmission signal by the frequency assignment unit 122. More specifically, the communication device 200 shortens the time during which the communication device 100 transmits the transmission signal at a frequency in the vicinity of the notch (the notch portion or its surroundings), so that the communication device 200 can detect the error included in the de-interleaved data. Can be removed by error correction.

  Here, the frequency assignment unit 122 periodically changes the transmission frequency assigned to each of the plurality of transmission signals. At that time, the frequency allocation unit 122 uses the M sequence to perform transmission frequency allocation so that a plurality of transmission signals are not simultaneously allocated to one transmission frequency. That is, the frequency allocation unit 122 allocates a different transmission frequency to each transmission signal.

FIG. 4 is an explanatory diagram illustrating an example of a column vector based on an M sequence (Maximum Length Sequence), which is a source of a matrix used by the frequency allocation unit 122. The column vector M ₀ in the figure is a time series of shift register values in a k-stage (that is, generated using a k-bit shift register) M-sequence generation process capable of generating a GOLD code. And has the same number of elements as the period 2 ^k −1 of the M sequence.

In addition, the column vector M ₁ (1) is a type in which shift register values in the generation process of a k-stage M sequence capable of generating a GOLD code are arranged in time series, which is different from the column vector M _0. Similarly to the column vector M ₀ , it has the same number of elements as the period 2 ^k −1 of the M sequence.
The column vector M _{1 (2)} is the initial value of the column vectors M _{1 (1)} from the initial value is (increased in the example of FIG. 4) 1 change, obtained in the same manner as column vectors M _{1 (1)} Column vector. Frequency assignment unit 122, thus column vector _M 1 (1) Initial value ² k -1 one obtained by changing one by one to ² k -1 column vector _{M 1 (1) ~M 1 (} 2 and ^k -1), is generated by using the column vector M _0, allocates frequencies on the basis of the matrix shown in FIG.

FIG. 5 is an explanatory diagram illustrating an example of a matrix used by the frequency allocation unit 122. The first column of the matrix shown in the figure has, as column elements M ₀ and M ₁ (1), a value obtained by taking the exclusive OR of each bit for each row as an element of each row. Similarly, the i-th column (1 ≦ i ≦ 2 ^k −1) of the matrix is a value obtained by calculating the exclusive OR of each bit for each row for the column vectors M ₀ and M ₁ (i). As an element.

Thus, the matrix shown in FIG. 5 is a matrix of 2 ^k −1 rows × 2 ^k −1 columns. This matrix does not have the same number in the same row and column. Further, when each element is viewed as a binary number and each column is regarded as a series, the value of this series increases or decreases in various sizes, and in this respect, it can be used as a series of random numbers.

Therefore, the frequency allocation unit 122 allocates each column in this matrix to a different transmission signal, allocates each element value viewed as a binary number to a different transmission frequency, and selects one of the rows. Since they do not have the same numerical value, each transmission signal can be assigned to a different transmission frequency.
Furthermore, the frequency allocating unit 122 allocates each transmission signal to a different transmission frequency by shifting the selected row by one at regular time intervals (decrease by 1 at regular time intervals or increase by 1 at regular time intervals). In addition, it is possible to randomly change the transmission frequency to be assigned.

FIG. 6 is an explanatory diagram illustrating an example of transmission frequency allocation performed by the frequency allocation unit 122. In the example of the figure, the communication system 1 has 2 ^k −1 transmission frequencies in a communication bandwidth wider than the notch interval 1 / τ. The frequency allocation unit 122 allocates each of the transmission frequencies to, for example, 2 ^k −1 or less (or transmission signal) single carrier users. At that time, the frequency allocation unit 122 allocates a different transmission frequency to each user and allocates one transmission frequency to all users at each time. On the other hand, when the row in the matrix of FIG. 5 makes one round, each user is assigned with each transmission frequency once.

  That is, as described with reference to FIG. 5, the frequency allocation unit 122 allocates various transmission frequencies while randomly changing the transmission frequency allocated to each user. Therefore, it is possible to avoid a situation where a transmission frequency near the notch is continuously assigned to a specific user. For each user, it is expected that the communication device 200 can remove errors included in the deinterleaved data by error correction because the time for assigning the transmission frequency near the notch is short.

  Here, if the communication bandwidth to which the transmission frequency assigned by the frequency assignment unit 122 is set is narrow and the bandwidth is in the vicinity of the notch, the transmission frequency assigned to each user by the frequency assignment unit 122 is changed. However, before and after the change, any transmission frequency becomes a frequency in the vicinity of the notch, and the state in which the reception radio wave characteristic deteriorates continues. As the received radio wave characteristics continue to deteriorate, the number of errors included in the deinterleaved data exceeds the number that can be corrected, and retransmission is required. End up.

  In order to avoid such a situation, it is required that the transmission frequency allocated by the frequency allocation unit 122 is not concentrated in the vicinity of the notch. Therefore, it is conceivable to use a certain frequency band as a communication band. In particular, by using a frequency band wider than the notch interval 1 / τ as a communication band, a frequency at which received power is maximized is included in the communication band, and good communication results are expected in the vicinity of the frequency. obtain.

  On the other hand, when the communication band is widened, there is a risk that the transmission / reception circuit becomes complicated, the circuit scale increases, and interference with other communication systems may occur, and the communication band that the communication system 1 can use is limited. Therefore, the frequency pattern calculation unit 222 detects notch intervals based on the frequency characteristics of the channels measured by the frequency characteristic measurement unit 221 and sets a communication band used by the communication system 1 according to the detected intervals. This point will be described with reference to FIG.

FIG. 7 is an explanatory diagram illustrating an example of a signal pattern transmitted by the communication apparatus 100. As shown in the figure, the communication apparatus 100 inserts a pilot signal, for example, periodically and transmits it to the communication data signal at all frequencies in the communication band.
The frequency characteristic measurement unit 221 is known about the transmission timing, phase, and amplitude of the pilot signal, and measures the frequency characteristic of the channel between the communication apparatus 100 and the communication apparatus 200 using the pilot signal.
However, the present invention does not depend on the channel estimation method. For example, pilot signal mapping different from the mapping shown in FIG. 7 may be performed, or a channel estimation method other than using pilot signals may be used.

Here, the amplitude and phase of the transmission signal (complex notation thereof; the same applies to others) are set to a _i , the preceding wave channel is set to h _i , the delayed wave channel is set to h _i−Δ, and additive white Gaussian noise (Additive When White Gaussian Noise (AWGN) is n _i , the received signal y _i is expressed as in Equation (3).

When both sides of this equation (3) are divided by a _i , equation (4) is obtained.

Here, when the magnitude of the noise is sufficiently smaller than the signal power, the noise n _i can be ignored with respect to the received signal y _i , as shown in Equation (5).

“H _i + h _i−Δ ” on the left side of the equation (5) indicates the frequency characteristics of the preceding wave and the delayed wave, and the frequency characteristic measuring unit 221 uses the frequency information of the notch (FIG. 2) based on this information. The notch period 1 / τ described with reference to FIG. 6 is calculated and output to the frequency pattern calculation unit 222.
Then, the frequency pattern calculation unit 222 sets a communication band having a bandwidth equal to or wider than the notch frequency interval calculated by the frequency characteristic measurement unit 221.

For example, the frequency pattern calculation unit 222 determines a communication bandwidth by multiplying a notch frequency interval by a coefficient (for example, 1.2) stored in advance. And the frequency pattern calculation part 222 memorize | stores beforehand the lower limit of the communication band which the communication system 1 uses, and sets the frequency band for the communication bandwidth determined from the said lower limit to a communication band.
In addition, the frequency pattern calculation unit 222 stores M stages having several stages in advance, and the sequence length (the number of stages multiplied by 2) is determined according to information on the number of signals (for example, the number of users) transmitted from the communication apparatus 100. -1) selects the M sequence having the shortest sequence length among the M sequences longer than the number of signals. The sequence length of the M sequence corresponds to the number of frequencies used by the communication system 1.
Then, the frequency pattern calculation unit 222 outputs information indicating the determined communication band and M sequence to the frequency setting unit 223 and the frequency setting unit 121.

Thus, the frequency pattern calculation unit 222 can set the communication bandwidth relatively narrow by setting the communication band according to the notch interval. By not requiring a wide bandwidth, the configuration of the communication system 1 can be simplified. Moreover, the possibility of interference of other communication systems can be reduced.
In addition, the frequency pattern calculation unit 222 can avoid preparing more frequencies than necessary by selecting an M-sequence corresponding to the notch interval (determining the number of transmission frequencies). It is possible to effectively use the communication band, such as preventing interference by taking a wide area.

Next, the operation of the communication system 1 will be described with reference to FIG.
FIG. 8 is an explanatory diagram showing a procedure of processing performed by the communication system 1. The communication system 1 periodically performs the process shown in FIG.

In the process of FIG. 5, first, the frequency characteristic measuring unit 221 measures the frequency characteristic of the channel and outputs it to the frequency pattern calculating unit 222 (step S111). Then, the frequency pattern calculation unit 222 calculates the frequency interval of the notch based on the frequency characteristic measured by the frequency characteristic measurement unit 221 and determines the required frequency width (that is, the communication bandwidth) based on the frequency interval ( Step S112).
Also, the frequency pattern calculation unit 222 acquires the number of necessary frequencies, for example, acquires information on the number of users from the communication device 100 (step S113). Then, the frequency pattern calculation unit 222 selects the M series having the number of stages according to the number of necessary frequencies (step S114).

The frequency pattern calculation unit 222 multiplies the number of determined M-sequence stages to the power of 2 and subtracts 1 (that is, the number of transmission frequencies) multiplied by the bandwidth required for each transmission frequency. The required bandwidth is compared with the communication bandwidth determined in step S112, and it is determined whether the required bandwidth is secured (step S115).
When it is determined that the necessary bandwidth can be secured (step S115: YES), the frequency pattern calculation unit 222 notifies the frequency setting unit 223 and the frequency setting unit 121 of the determined communication band and M sequence ( Step S131).

Then, communication device 100 and communication device 200 determine transmission frequency and communication signal allocation based on the communication band and M-sequence determined by frequency pattern calculation unit 222, and synchronize the transmission frequency and the allocation of the transmission signal. Communication is started (step S132).
Thereafter, the process of FIG.

On the other hand, if it is determined in step S115 that the necessary bandwidth has not been secured (step S115: NO), the frequency pattern calculation unit 222 raises the number of stages of the M sequence to a power of 2 and subtracts 1 (M The bandwidth required for communication, which is the sequence length of the sequence and corresponds to the number of transmission frequencies) multiplied by the bandwidth required for each transmission frequency, is equal to or less than the communication bandwidth determined in step S112. The number of stages of the M series is selected (step S121). That is, the frequency pattern calculation unit 222 reselects the M series corresponding to the bandwidth.
Thereafter, the process proceeds to step S131.

As described above, the frequency allocating unit 122 allocates communication signals to frequencies based on M sequences, so that communication signals can be randomly allocated to frequencies. Therefore, it can be avoided that the same signal is continuously assigned in the vicinity of the notch, and the influence of the notch can be reduced.
In addition, since the generation of the M series can be performed using a shift register, the configuration of the communication system 1 can be relatively simplified.

  Moreover, the frequency pattern calculation unit 222 sets a communication band according to the notch interval, so that a part other than the notch is included in the communication band, and the communication band can be made relatively narrow. By relatively narrowing the communication band, the device provided in the frequency pattern calculation unit 222 can be simplified, and interference with other communication systems can be avoided.

  In addition, the frequency pattern calculation unit 222 selects the M series according to the number of communication signals, so that the communication band can be effectively used, such as the communication frequency interval being relatively wide to prevent interference between signals.

Next, a minimum configuration in the communication apparatus 100 will be described with reference to FIG.
FIG. 9 is a schematic block diagram showing the minimum configuration of the present invention in the communication apparatus 100 among the units shown in FIG. In the figure, a frequency allocation unit 122 and a modulation unit 141 are shown among the units of the communication apparatus 100 shown in FIG.

  In this configuration, as described above based on the configuration shown in FIG. 1, frequency allocation section 122 determines allocation of transmission signals and transmission frequencies using M-sequences, and modulation section 141 performs frequency allocation. The transmission signal is transmitted according to the assignment determined by unit 122. Thereby, since a communication signal can be randomly assigned to a frequency, it can be avoided that the same signal is continuously assigned in the vicinity of the notch, and the influence of the notch can be reduced.

A program for realizing all or part of the functions of communication device 100 or communication device 200 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. By doing so, you may process each part. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Communication system 100,200 Communication apparatus 111 Error correction encoding part 112 Interleaver 121,223 Frequency setting part 122 Frequency allocation part 131 Pilot signal generation part 141 Modulation part 151,211 Antenna 221 Frequency characteristic measurement part 222 Frequency pattern calculation part 224 Frequency Assignment detector 231 Demodulator 232 Deinterleaver 233 Error correction decoder

Claims (7)

A modulation section that modulates and transmits a plurality of signals using the same number or more frequencies as the number of signals;
A frequency allocation unit that allocates each of the plurality of signals to the frequency,
The frequency allocating unit has a first M sequence and the same period as the first M sequence, a code length of each code has the same code length as a code of the first M sequence, and Exclusive logic for each bit of the second M sequence, which is a different type of M sequence from the first M sequence, and each of the one or more M sequences in which the initial value of the second M sequence is changed A communication apparatus characterized by assigning each of the plurality of signals to the frequency based on the same number of sequences as the number of transmission signals .   The communication apparatus according to claim 1, wherein the frequency allocation unit allocates the plurality of signals to the frequencies included in a frequency displacement width calculated based on an interval between notch portions.   3. The communication according to claim 1, wherein the frequency allocation unit generates a number of numerical values corresponding to the number of signals using an M-sequence having a number of stages corresponding to the number of signals to be transmitted. apparatus. A demodulator that receives a signal and demodulates it for each frequency;
The first M sequence has the same period as the first M sequence, the code length of each code has the same code length as the code of the first M sequence, and the first M sequence The number of demodulated signals by exclusive OR for each bit of the second M sequence, which is a different type of M sequence, and one or more M sequences obtained by changing the initial values of the second M sequence A frequency allocation detection unit that detects a correspondence relationship between the frequency and the communication data based on the same number of sequences ;
A communication apparatus comprising: Comprising a first communication device and a second communication device;
The first communication device is
A modulation section that modulates and transmits a plurality of signals using the same number or more frequencies as the number of signals;
A frequency allocation unit that allocates each of the plurality of signals to the frequency,
The frequency allocating unit has a first M sequence and the same period as the first M sequence, a code length of each code has the same code length as a code of the first M sequence, and Exclusive logic for each bit of the second M sequence, which is a different type of M sequence from the first M sequence, and each of the one or more M sequences in which the initial value of the second M sequence is changed Assigning each of the plurality of signals to the frequency based on the same number of sequences as the number of transmitted signals by sum ,
The second communication device is
A demodulator that receives a signal and demodulates it for each frequency;
Based on the same sequence as the sequence used by the frequency allocation unit, a frequency allocation detection unit that detects a correspondence relationship between the frequency and communication data;
A communication system comprising: A modulation step of modulating and transmitting a plurality of signals using the same number or more frequencies as the number of signals;
A frequency assignment step for assigning each of the plurality of signals to the frequency,
In the frequency allocation step, the first M sequence has the same period as the first M sequence, the code length of each code has the same code length as the code of the first M sequence, and Exclusive logic for each bit of the second M sequence, which is a different type of M sequence from the first M sequence, and each of the one or more M sequences in which the initial value of the second M sequence is changed A communication method characterized by allocating each of the plurality of signals to each of the frequencies based on the same number of sequences as the number of transmission signals . A computer that controls a communication device including a modulation unit that modulates and transmits a plurality of signals using the same number or more frequencies as the number of signals,
Performing a frequency assignment step of assigning each of the plurality of signals to the frequency;
In the frequency allocation step, the first M sequence has the same period as the first M sequence, the code length of each code has the same code length as the code of the first M sequence, and the first Exclusive MOR for each bit of one M sequence and a second M sequence that is a different type of M sequence, and each of one or more M sequences in which the initial value of the second M sequence is changed The program for assigning each of the plurality of signals to the frequency based on the same number of sequences as the number of transmission signals .

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