Transmitter station identification signal generator, transmission system, measuring device, and program

Abstract

To enable identification of the transmitting station from the received signal. [Solution] The transmitting station identification signal generation device 10 includes a PRBS generation unit (111) that generates a PRBS signal using an M sequence, a cyclic shift unit (112) that generates a cyclic shift signal by cyclically shifting the PRBS signal based on a transmitting station identification code assigned to the transmitting station, a subcarrier modulation unit (113) that generates a data carrier by phase shift modulation of the cyclic shift signal, and a signal generation unit (114, 115, 116) that generates a transmitting station identification signal by inserting a null carrier into the data carrier and performing OFDM modulation.

Description

[Technical Field]

[0001] The present invention relates to a transmitting station identification signal generation device, a transmitting system, a measuring device, and a program. [Background technology]

[0002] To provide terrestrial broadcasting services to all areas, many relay stations are needed throughout the country. In Japan, the broadcasting network is composed of various types of transmission stations, including main stations capable of covering large areas with a single transmission station, relay stations, and mini-satellite stations, and broadcasters are responsible for maintaining and operating all of the transmission equipment.

[0003] Surveys of reception conditions for each broadcasting station (number of receiving households, broadcasting area, etc.) play an important role in ensuring a good broadcasting reception environment. For example, if a broadcasting station is damaged by a large-scale disaster, this data should be used as a reference when deciding on the initial response. Also, in areas with declining populations or where CATV has become widespread, it is not uncommon for the number of receiving households that existed when the current terrestrial digital broadcasting service first started to decrease significantly. There is a possibility that there are relay stations that had viewers when they first started broadcasting but are no longer viewed, and from the perspective of the continuity of broadcasting operations, the results of reception condition surveys can be useful data for management.

[0004] Non-patent document 1 describes a next-generation advanced terrestrial broadcasting system that inherits the features of the current ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) system, in which a unique transmitting station identification code is assigned to the main station and each relay station, and this code is superimposed onto the broadcast wave. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Asakura, et al., "A Study on Transmitter Station Identification Codes in Advanced Terrestrial Broadcasting Systems," Proceedings of the IEICE General Conference, Vol. 1, March 2024, B-5B-01, p.386. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The first challenge is that within an area comprising an SFN (Single Frequency Network), the radio waves from multiple transmitting stations all use the same frequency and waveform, making it difficult to conduct detailed reception surveys to determine "which transmitting station's signal is being received primarily." In areas where radio waves from multiple transmitting stations can be received, a method of visually checking whether the receiving antenna is pointed towards the target transmitting station is used, but the result does not provide conclusive evidence that the signal is "primarily being received" from that station. Furthermore, the current ISDB-T system does not have a function to identify transmitting stations.

[0007] The second challenge is that, within the SFN area, when drawing a delay profile from a pilot signal synthesized from multiple transmitting stations and confirming the presence of reflected and delayed waves, it is possible to confirm the presence or absence of delayed waves other than the main wave (the radio waves from the main transmitting station), but it is not possible to distinguish whether the delayed wave is a reflected wave of the main wave or an incoming wave from another transmitting station that makes up the SFN. Traditionally, it was only possible to estimate this from the amount of delay relative to the main wave and the positional relationship of the transmitting stations, making it impossible to investigate the reception conditions accurately.

[0008] In view of these circumstances, the object of the present invention is to solve the first problem and make it possible to identify the transmitting station from the received wave. Furthermore, the object of the present invention is to solve the second problem and make it possible to distinguish whether a delayed wave is a reflected wave of the main wave or an incoming wave from another transmitting station. [Means for solving the problem]

[0009] The gist of the present invention, which solves the above problems, is as follows.

[0010] (1) A transmitting station identification signal generation device comprising: a PRBS (Pseudo-Random Binary Sequence) generation unit that generates a PRBS signal using an M sequence; a cyclic shift unit that generates a cyclic shift signal by cyclically shifting the PRBS signal based on a transmitting station identification code assigned to the transmitting station; a subcarrier modulation unit that generates a data carrier by phase shift modulating the cyclic shift signal; and a signal generation unit that generates a transmitting station identification signal by inserting a null carrier into the data carrier and performing OFDM (Orthogonal Frequency Division Multiplexing) modulation.

[0011] (2) The transmitting station identification signal generating device according to (1), wherein the signal generating unit sets the carrier number of the data carrier to be the same as the data carrier in the one-segment band of the ISDB-T terrestrial digital broadcasting signal, and sets the carrier number of the null carrier to be the same as the non-data carrier in the one-segment band.

[0012] (3) A transmission system comprising: a transmitting station identification signal generating device as described in (1) or (2); a modulator that generates an ISDB-T signal which is an ISDB-T terrestrial digital broadcasting signal; and an adder that outputs an OFDM signal obtained by power multiplexing the transmitting station identification signal in the one-segment band of the ISDB-T signal.

[0013] (4) A measuring device for receiving the OFDM signal from the transmission system described in (3), comprising: a PRBS generation unit that generates a PRBS signal using an M sequence; a cyclic shift unit that sequentially generates cyclic shift signals obtained by cyclically shifting the PRBS signal based on all patterns of the transmitting station identification code; a transmission replica signal generation unit that generates a replica signal of the transmitting station identification signal from the cyclic shift signals; a correlation coefficient calculation unit that calculates a correlation coefficient between the OFDM signal and the transmission replica signal; and a transmitting station identification code detection unit that detects the transmitting station identification code when the correlation coefficient is largest.

[0014] A measuring device that receives the OFDM signal from the transmission system described in (5)(3), comprising: a PRBS generation unit that generates a PRBS signal using an M sequence; a cyclic shift unit that generates a cyclic shift signal obtained by cyclically shifting the PRBS signal based on the transmission station identification code of the transmission station to be measured; a transmission replica signal generation unit that generates a replica signal of the transmission station identification signal from the cyclic shift signal; a correlation coefficient calculation unit that calculates the correlation coefficient between the OFDM signal and the replica signal; and a delay profile generation unit that detects the peak of the correlation coefficient while shifting the FFT window position and generates a delay profile indicating the relationship between the time when the FFT window position is shifted and the peak.

[0015] (6) The program according to one embodiment causes a computer to function as the transmission station identification signal generation device described in (1) or (2).

[0016] (7) The program according to one embodiment causes a computer to function as the measuring device described in (4) or (5). [[Effect of the Invention]]

[0017] According to the present invention, it becomes possible to identify a transmission station from a received wave. Further, it becomes possible to distinguish whether the delayed wave is a reflected wave of the main wave or an incoming wave from another transmission station. [[Brief Description of the Drawings]]

[0018] [Figure 1] It is a diagram showing a configuration example of a transmission system including a transmission station identification signal generation device according to one embodiment. [Figure 2] It is a block diagram showing a configuration example of a transmission station identification signal generation unit in a transmission station identification signal generation device according to one embodiment. [Figure 3] It is a block diagram showing a configuration example of a PRBS generation unit in a transmission station identification signal generation device according to one embodiment. [Figure 4] It is a diagram for explaining the power multiplexing of the transmission station identification signal. [Figure 5]It is a block diagram showing a configuration example of a measurement device according to the first embodiment. [Figure 6] It is a block diagram showing a configuration example of a measurement device according to the second embodiment. [Figure 7] It is a system diagram of computer simulation. [Figure 8] It is a diagram showing the one-segment bit error rate characteristics when the transmission station identification signal is not multiplexed and when it is multiplexed, obtained by computer simulation. [Figure 9] It is a diagram showing an example of a correlation coefficient obtained by computer simulation. [Figure 10] It is a diagram showing an example of a delay profile obtained by computer simulation.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0020] FIG. 1 is a block diagram showing a configuration example of a transmission system including a transmission station identification signal generation device according to an embodiment. The transmission system 1 shown in FIG. 1 includes a transmission station identification signal generation device 10, a modulator 3, an adder 4, and a transmitter 5.

[0021] The transmission system 1 is used in a transmission station (parent station or relay station). A unique transmission station identification code is assigned to each transmission station, and the transmission system 1 superimposes a transmission station identification signal on the current (ISDB-T system) terrestrial digital broadcast signal.

[0022] The modulator 3 generates an ISDB-T signal, which is an ISDB-T system terrestrial digital broadcast signal, and outputs it to the adder 4. The modulator 3 is a conventional ISDB-T system modulator and does not have a function of transmitting a transmission station identification code. The modulator 3 may be an equalizer.

[0023] The adder 4 outputs an OFDM signal to the transmitter 5, which is obtained by power multiplexing the transmitter station identification signal generated by the transmitter station identification signal generator 10 onto the one-segment bandwidth of the ISDB-T signal generated by the modulator 3.

[0024] Transmitter 5 transmits the OFDM signal, which has been power multiplexed by adder 4, via antenna.

[0025] The transmitting station identification signal generation device 10 generates a transmitting station identification signal that indicates a transmitting station identification code for identifying a transmitting station. The transmitting station identification signal generation device 10 shown in Figure 1 comprises a transmitting station identification signal generation unit 11, a postfix / prefix addition unit 12, and a level adjustment unit 13. An adder 4 may also be provided in the transmitting station identification signal generation device 10.

[0026] Figure 2 shows an example of the configuration of the transmitting station identification signal generation unit 11. The transmitting station identification signal generation unit 11 shown in Figure 2 comprises a PRBS generation unit 111, a cyclic shift unit 112, a subcarrier modulation unit 113, a null carrier indicator unit 114, an OFDM modulation unit 115, and an IFFT (Inverse Fast Fourier Transform) unit 116.

[0027] The PRBS generation unit 111 generates a PRBS (Pseudo-Random Binary Signal Sequence) signal using the M-sequence (Maximum Length Sequence) pseudo-random number generation algorithm and outputs it to the cyclic shift unit 112. The M-sequence is generated by a p-bit shift register and has a period of 2 p This is a sequence of -1. For example, since there are 276 data carriers in the One-Seg bandwidth, the PRBS generation unit 111 generates a PRBS signal based on an 8th-order generating polynomial. The generating polynomial G(x) is, for example, the one shown in equation (1). By using an 8th-order generating polynomial, the bit sequence with a code length of 256 has excellent autocorrelation characteristics.

[0028]

number

[0029] Fig. 3 shows a circuit example of the PRBS generation unit 111. Fig. 3 shows an M sequence generated by an eighth-order generating polynomial as W i and shows a PRBS generation circuit based on Equation (1) when the generating polynomial is Equation (1). The initial values of the shift registers in the circuit are all set to 1. W i Let the M sequence signal obtained by assigning 0 of W to 1 and 1 to -1 be a n . The transmission system 1 transmits an 8-bit transmission station identification code according to the shift amount of the M sequence generated by Equation (1).

[0030] The cyclic shift unit 112 generates a cyclic shift signal b n by cyclically shifting the PRBS signal (M sequence signal) a m,n generated by the PRBS generation unit 111 based on the transmission station identification code assigned to the transmission station including the transmission system 1, and outputs it to the sub-carrier modulation unit 113. When the transmission station identification code is m, the shifted M sequence signal b m,n is expressed by Equation (2). Here, N represents the number of data carriers in the one-segment band.

[0031]

Equation

[0032] The M sequence has a self-correlation peak only once per period. Therefore, the correlation coefficient Φ(k) with the signal sequence before the shift is expressed by Equation (3), and signal detection can be performed by utilizing the fact that a peak occurs only at k = m when 0 ≤ k < N.

[0033]

Equation

[0034] The sub-carrier modulation unit 113 generates a data carrier obtained by phase shift modulation (specifically, BPSK modulation) of the cyclic shift signal generated by the cyclic shift unit 112, and outputs it to the OFDM modulation unit 115.

[0035] The null carrier indicator unit 114 outputs information to the OFDM modulation unit 115 indicating the carrier number or frequency (both are synonymous, so hereinafter simply referred to as "carrier number") of the null carrier. The AC (Auxiliary Channel), TMCC (Transmission and Multiplexing Configuration Control), and SP (Scattered Pilot) carriers in the one-segment band of the ISDB-T signal, i.e., non-data carriers, are also used for demodulation of another layer (full-segment) other than one-segment, so it is preferable not to power multiplex these carriers in order to avoid affecting full-segment. Therefore, the null carrier indicator unit 114 indicates the carrier number of the non-data carrier in the one-segment band of the ISDB-T signal to the OFDM modulation unit 115.

[0036] The OFDM modulation unit 115 generates an OFDM symbol by inserting a null carrier with a carrier number specified by the null carrier indicator unit 114 into the data carrier that has been phase-shift modulated by the subcarrier modulation unit 113, and outputs the OFDM symbol, which is a frequency domain signal, to the IFFT unit 116. The OFDM modulation unit 115 uses the same FFT clock and subcarrier spacing as the modulator 3, and shares the same frequency arrangement for the transmitting station identification signal and the ISDB-T signal. That is, the OFDM modulation unit 115 sets the carrier number of the data carrier to be the same as the data carrier in the one-segment band of the ISDB-T signal, and sets the carrier number of the null carrier to be the same as the non-data carrier in the one-segment band of the ISDB-T signal. In this way, when the adding unit 4 multiplexes the transmitting station identification signal to the ISDB-T signal, power multiplexing to the non-data carrier is avoided, and the signal does not affect the full-segment signal.

[0037] The IFFT unit 116 performs IFFT processing on the OFDM symbols generated by the OFDM modulation unit 115 to generate a time-domain transmitting station identification signal.

[0038] Refer to Figure 1 again. The postfix / prefix addition unit 12 adds a postfix and / or prefix to the time-domain signal output from the transmitting station identification signal generation unit 11 and outputs it to the level adjustment unit 13. The addition method may be, for example, copying the last 1 / 8 of the time domain of the symbol to the front, like a guard interval, or copying the first 1 / 16 and last 1 / 16 of the time domain of the OFDM symbol to the front and back, respectively. This process is performed on the measuring device side in order to detect the OFDM symbol region in the time domain using the correlation characteristics of the postfix and / or prefix.

[0039] The level adjustment unit 13 reduces the power of the transmitting station identification signal input from the postfix / prefix addition unit 12 based on the injection level (IL). The injection level is the power ratio of the transmitting station identification signal added to the ISDB-T signal. The larger the IL, the smaller the interference to the ISDB-T signal (main line). In practice, it is necessary to set the IL to a sufficiently large value so that the impact on the ISDB-T signal becomes negligibly small.

[0040] Figure 4 illustrates the power multiplexing of the transmitting station identification signal, showing the carrier configuration of the ISDB-T signal in the one-segment band and the carrier configuration of the transmitting station identification signal. In the ISDB-T signal, the long arrows indicate non-data carriers corresponding to SP, AC, or TMCC, while the short arrows indicate data carriers. The transmitting station identification signal is composed of an OFDM symbol consisting of a data carrier with the same carrier number as the data carrier of the ISDB-T signal in the One-Seg band and a null carrier with the same carrier number as the non-data carrier of the ISDB-T signal in the One-Seg band. The ISDB-T signal and the transmitting station identification signal are power multiplexed by adder 4.

[0041] As described above, the transmitting station identification signal generation device 10 according to the present invention comprises a PRBS generation unit 111 that generates a PRBS signal using an M sequence, a cyclic shift unit 112 that generates a cyclic shift signal by cyclically shifting the PRBS signal based on a transmitting station identification code assigned to the transmitting station, a subcarrier modulation unit 113 that generates a data carrier by phase shift modulation of the cyclic shift signal, and a signal generation unit (null carrier instruction unit 114, OFDM modulation unit 115, and IFFT unit 116) that generates a transmitting station identification signal by inserting a null carrier into the data carrier and performing OFDM modulation. Japanese Patent Application Publication No. 2022-055256 also describes a method of power multiplexing a transmitting station identification signal in the One-Seg band of an ISDB-T signal, but while this method transmits information using a selected subcarrier pattern in the One-Seg band, the present invention uses a large number of subcarriers, 276, which improves resistance to frequency selectivity fading.

[0042] <Measuring device according to the first embodiment> Next, a measuring device according to the first embodiment will be described.

[0043] Figure 5 is a block diagram showing an example configuration of a measuring device according to the first embodiment. The measuring device 2a shown in Figure 5 comprises a PRBS generation unit 21, a cyclic shift unit 22, a transmit replica signal generation unit 23, a postfix / prefix removal unit 24, an FFT (Fast Fourier Transform) unit 25, a correlation coefficient calculation unit 26, and a transmitting station identification code detection unit 27. The measuring device 2a receives an OFDM signal from the transmitting system 1 and detects the transmitting station identification code.

[0044] The PRBS generation unit 21, similar to the PRBS generation unit 111 of the transmitting station identification signal generation device 10, uses the M sequence to generate the PRBS signal a' n It generates and outputs to the cyclic shift unit 22.

[0045] The cyclic shift unit 22 cyclically shifts the PRBS signal generated by the PRBS generation unit 21 by m bits based on all patterns of the transmitting station identification code, and generates a cyclic shift signal b'.m,n are sequentially generated and output to the transmission replica signal generation unit 23. When the transmission station identification code is 8 bits, m is set to 0 to 255, and the value of m is sequentially changed to generate the cyclic shift signal b’ m,n are sequentially generated.

[0046] The transmission replica signal generation unit 23 performs the same processing as the sub-carrier modulation unit 113, the null carrier indication unit 114, and the OFDM modulation unit 115 of the transmission station identification signal generation device 10 on each cyclic shift signal generated by the cyclic shift unit 22, generates a replica signal (transmission replica signal) of the transmission station identification signal from the cyclic shift signal, and sequentially outputs it to the correlation coefficient calculation unit 26.

[0047] The postfix / prefix removal unit 24 removes the postfix and / or prefix added by the postfix / prefix addition unit 12 of the transmission station identification signal generation device 10 from the received OFDM signal according to a predetermined FFT window position, extracts the OFDM signal in the valid symbol period, and outputs it to the FFT unit 25.

[0048] The FFT unit 25 performs FFT processing on the OFDM signal input from the postfix / prefix removal unit​​​​​​​​​​​Since the possible values ​​for the transmitting station identification code are known in advance (any value from 0 to 255 if it is 8 bits), the measuring device 2a generates a transmission replica signal corresponding to all patterns of the transmitting station identification code. By correlating the transmission replica signal with the received wave (received OFDM signal), the transmitting station identification code can be detected without demodulating the One-Seg data. By detecting the transmitting station identification code, it becomes possible to determine which transmitting station households in the SFN area are primarily receiving.

[0052] <Measuring device according to the second embodiment> Next, a measuring device according to the second embodiment will be described.

[0053] Figure 6 is a block diagram showing an example configuration of a measuring device according to the second embodiment. The measuring device 2b shown in Figure 6 comprises a PRBS generation unit 21, a cyclic shift unit 22, a transmit replica signal generation unit 23, a postfix / prefix removal unit 24, an FFT unit 25, a correlation coefficient calculation unit 26, an FFT window position control unit 28, a correlation peak detection unit 29, and a delay profile generation unit 30. The measuring device 2b differs from the measuring device 2a in that it includes an FFT window position control unit 28, and replaces the transmit station identification code detection unit 27 with a correlation peak detection unit 29 and a delay profile generation unit 30. The measuring device 2b receives an OFDM signal from the transmit system 1 and outputs a delay profile of a transmit station whose transmit station identification code or candidate therefor is known.

[0054] The PRBS generation unit 21, similar to the PRBS generation unit 111 of the transmitting station identification signal generation device 10, uses the M sequence to generate the PRBS signal a' n It generates and outputs to the cyclic shift unit 22.

[0055] The cyclic shift unit 22 receives the transmission station identification code c of the transmission station to be measured, and cyclically shifts the PRBS signal generated by the PRBS generation unit 21 by c bits to obtain the cyclic shift signal b'. c,n It generates and outputs to the transmission replica signal generation unit 23. The transmitting station identification code c may have multiple candidate values.

[0056] The transmit replica signal generation unit 23 performs the same processing on the cyclic shift signal generated by the cyclic shift unit 22 as the subcarrier modulation unit 113, null carrier instruction unit 114, and OFDM modulation unit 115 of the transmit station identification signal generation device 10, generating a replica signal of the transmit station identification signal (transmit replica signal) from the cyclic shift signal and outputting it to the correlation coefficient calculation unit 26.

[0057] The FFT window position control unit 28 shifts the FFT window position (delay amount relative to the main wave) by a predetermined clock cycle (for example, 1 clock cycle) and outputs information indicating the FFT window position to the postfix / prefix removal unit 24 and the delay profile generation unit 30.

[0058] The FFT unit 25 converts the time-domain signal cut off by the FFT window into a frequency-domain signal and outputs it sequentially to the correlation coefficient calculation unit 26.

[0059] The correlation coefficient calculation unit 26 calculates the correlation coefficient between the transmitted replica signal input from the transmitted replica signal generation unit 23 and the OFDM signal input from the FFT unit 25 for each FFT window position and outputs it to the correlation peak detection unit 29.

[0060] The correlation peak detection unit 29 detects the maximum absolute value of the correlation coefficient calculated by the correlation coefficient calculation unit 26 (hereinafter referred to as the "correlation peak") and outputs it to the delay profile generation unit 30.

[0061] The delay profile generation unit 30 generates a delay profile that shows the relationship between the time shifted by the FFT window position and the correlation peak. Specifically, the delay profile generation unit 30 acquires data with the horizontal axis representing the time shifted by the FFT window position and the vertical axis representing the correlation peak. The delay profile generation unit 30 sets the time showing the largest correlation peak as zero and generates a delay profile by plotting the correlation peak against its relative time (delay time relative to the main wave).

[0062] Since the expected transmitting station identification codes at the receiving point can be narrowed down in advance, the measuring device 2b can draw a delay profile for each transmitting station, enabling a detailed analysis of whether the delayed wave relative to the main wave is a reflected wave or an incoming wave from a transmitting station other than the main station.

[0063] <Verification by computer simulation> To verify the effectiveness of the present invention, computer simulations were performed. Figure 7 shows the system diagram of the computer simulation. The modulation parameters for the ISDB-T system were set to be the same as those used in current terrestrial digital broadcasting. Two SFN environments were assumed, designated as station A and station B.

[0064] First, assuming an environment where only station A is received, we evaluate the impact of the present invention on the transmission characteristics of One-Seg. Figure 8 shows the bit error rate (BER) characteristics of One-Seg when the transmitting station identification signal is not multiplexed and when the transmitting station identification signal with IL=17dB is multiplexed. BER represents the value after Viterbi decoding, and the BER that becomes error-free after Reed-Solomon coding is BER=1×10⁻⁶. -4 When evaluated with a C / N that satisfies the following conditions, it can be seen that the C / N degradation of One-Seg due to power multiplexing of a transmitting station identification signal with IL=17dB is very small, at 0.2dB.

[0065] Next, a transmitter identification signal is transmitted at IL=17dB to detect the transmitter identification code. Figure 9 shows the correlation coefficient between the transmitted transmitter identification signal and the demodulated and generated transmitted replica signal, with the transmitter identification code set to 100. The C / N ratio was set to 20dB, assuming fixed reception of current terrestrial digital broadcasting. It can be seen that a correlation peak is detected when the transmitter identification code is 100.

[0066] Next, we will assume a two-station SFN environment and confirm that delay profiles can be generated for each transmitting station. Let the transmitting station identification code of station A be 100 and the transmitting station identification code of station B be 200. Let the delay time of station B relative to station A be 63 microseconds and the power ratio (D / U) be 3 dB. Let the IL = 17 dB and C / N = 20 dB of the transmitting station identification signal. Figure 10 shows the delay profile in this case. It can be seen that both stations A and B are correctly detected and delay profiles can be generated.

[0067] <Program> To enable the above-described transmitting station identification signal generation device 10 and measuring devices 2a and 2b to function, a computer capable of executing program instructions can also be used. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notepad, etc. The program instructions may be program code, code segments, etc., for executing the required tasks.

[0068] A computer comprises a processor, a memory unit, an input unit, an output unit, and a communication interface. The processor may be a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), etc., and may be composed of multiple processors of the same or different types. The processor controls each of the above components and performs various calculations by reading and executing programs from the memory unit. At least a part of these processes may be implemented in hardware. The input unit is an input interface that receives user input operations and acquires information based on user operations, such as a pointing device, keyboard, or microphone. The output unit is an output interface that outputs information, such as a display or speaker. The communication interface is an interface for communicating with external devices.

[0069] The program may be recorded on a computer-readable recording medium. Using such a medium, the program can be installed on the computer. The recording medium on which the program is recorded may be a non-transitory recording medium. Non-transitory recording media are not particularly limited, but may include, for example, CD-ROMs, DVD-ROMs, or USB (Universal Serial Bus) memory. Alternatively, the program may be downloaded from an external device via a network.

[0070] Furthermore, the transmitting station identification signal generation device 10 described above may be composed of one or more semiconductor chips. This semiconductor chip may be equipped with a CPU that executes a program describing the processing content that realizes each function of the transmitting station identification signal generation device 10. The same applies to the measuring devices 2a and 2b.

[0071] Although the embodiments described above are representative examples, it will be apparent to those skilled in the art that many modifications and substitutions are possible within the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited by the embodiments described above, and various modifications or changes are possible without departing from the scope of the claims. For example, it is possible to integrate multiple component blocks shown in the configuration diagram of the embodiments, or to divide a single component block. [Explanation of Symbols]

[0072] 1. Transmission System 2a,2b Measuring device 3 Modulator 4 Adder 5 Transmitter 10 Transmitter station identification signal generator 11 Transmitter Station Identification Signal Generation Unit 12 Postfix / Prefix Addition Section 13 Level adjustment section 21,111 PRBS generation section 22,112 Shift work 23 Transmit Replica Signal Generation Unit 24 Postfix / Prefix Removal Section 25 FFT section 26 Correlation coefficient calculation unit 27 Transmitter Station Identification Code Detection Unit 28 FFT Window Position Control Unit 29 Correlation Peak Detection Unit 30 Delay Profile Generation Unit 113 Subcarrier Modulation Section 114 Null Carrier Indicator 115 OFDM Modulation Section 116 IFFT section

Claims

1. A PRBS generation unit that generates a PRBS signal using an M sequence, A cyclic shift unit generates a cyclic shift signal by cyclic shifting the PRBS signal based on the transmitting station identification code assigned to the transmitting station, A subcarrier modulation unit generates a data carrier obtained by phase shift modulation of the cyclic shift signal, A signal generation unit that generates a transmitting station identification signal by inserting a null carrier into the data carrier and modulating it using OFDM, A transmitting station identification signal generating device equipped with the following features.

2. The transmitting station identification signal generating device according to claim 1, wherein the signal generating unit sets the carrier number of the data carrier to be the same as the data carrier in the one-segment band of an ISDB-T terrestrial digital broadcasting signal, and sets the carrier number of the null carrier to be the same as the non-data carrier in the one-segment band.

3. A transmitting station identification signal generating device according to claim 1, A modulator that generates an ISDB-T signal, which is a terrestrial digital broadcasting signal using the ISDB-T method, An adder that outputs an OFDM signal obtained by power multiplexing the transmitting station identification signal into the one-segment band of the ISDB-T signal, A transmission system equipped with the following features.

4. A measuring device for receiving the OFDM signal from the transmission system described in claim 3, A PRBS generation unit that generates a PRBS signal using an M sequence, A cyclic shift unit sequentially generates cyclic shift signals by cyclically shifting the PRBS signal based on all patterns of the transmitting station identification code, A transmission replica signal generation unit generates a replica signal of the transmitting station identification signal from the cyclic shift signal, A correlation coefficient calculation unit that calculates the correlation coefficient between the OFDM signal and the transmitted replica signal, A transmitting station identification code detection unit that detects the transmitting station identification code when the correlation coefficient is largest, A measuring device equipped with the following features.

5. A measuring device for receiving the OFDM signal from the transmission system described in claim 3, A PRBS generation unit that generates a PRBS signal using an M sequence, A cyclic shift unit generates a cyclic shift signal by cyclic shifting the PRBS signal based on the transmitter identification code of the transmitting station to be measured, A transmission replica signal generation unit generates a replica signal of the transmitting station identification signal from the cyclic shift signal, A correlation coefficient calculation unit calculates the correlation coefficient between the OFDM signal and the replica signal, A delay profile generation unit detects the peak of the correlation coefficient while shifting the FFT window position and generates a delay profile showing the relationship between the time the FFT window position is shifted and the peak, A measuring device equipped with the following features.

6. A program for causing a computer to function as a transmitting station identification signal generating device as described in claim 1.

7. A program for causing a computer to function as the measuring device described in claim 4 or 5.

Images