JP7574071B2 - Receiving device - Google Patents

Description

The present invention relates to a receiving device.

Conventionally, technology using the SC (Single Carrier)-FDE (Single Carrier-Frequency Domain Equalization) method has been known to reduce degradation of reception quality caused by fading and other issues that occur in radio wave transmission.

For example, in the SC-FDE method, a signal transmitted from one transmitting antenna is received by two or more receiving antennas, and diversity combining of the signals received by the two or more receiving antennas is performed using a maximum ratio combining method or the like (hereinafter, SIMO (Single-Input Multiple-Output)-SC-FDE method). In the following, the processing or configuration related to the signals received by each receiving antenna before diversity combining of the signals received by the two or more receiving antennas may be referred to as a "system."

Furthermore, technology has been proposed to improve the accuracy of identifying block numbers contained in transmission control information (hereinafter, TMCC (Transmission and Multiplexing Configuration Control) information) (for example, Patent Document 1).

JP 2019-140590 A

In diversity combining, it is believed that the more systems used for diversity combining, the better the reception quality after diversity combining (for example, the CN (Carrier to Noise) ratio). However, if systems that are not receiving signals properly are used for diversity combining, there is a possibility that the diversity effect will not be obtained.

Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a receiving device that makes it possible to appropriately obtain the diversity effect.

A receiving device according to one embodiment of the disclosure includes two or more receiving antennas that receive a block signal including transmission control information and data, two or more receiving systems that process the signals received by each of the two or more antennas, a synthesis processing unit that executes synthesis processing of the signals processed by the two or more receiving systems, and a control unit that controls the synthesis processing unit, and the control unit controls the synthesis processing unit based on whether an error has occurred in the transmission control information after execution of the synthesis processing.

The present invention provides a receiving device that can adequately obtain the diversity effect.

FIG. 1 is a diagram showing a digital wireless transmission system 10 according to an embodiment. FIG. 2 is a block diagram showing a transmitting device 100 according to the embodiment. FIG. 3 is a diagram illustrating an example of a TMCC according to the embodiment. FIG. 4 is a diagram illustrating an example of an SC-FDE block according to an embodiment. FIG. 5 is a block diagram showing a receiving device 200 according to the embodiment. FIG. 6 is a block diagram showing a receiving system 210 according to the embodiment. FIG. 7 is a block diagram showing a control operation according to the embodiment.

Next, an embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the ratios of the dimensions may differ from the actual ones.

Therefore, specific dimensions should be determined with reference to the following explanation. Of course, there are also parts in which the dimensional relationships and ratios differ between the drawings.

[Disclosure Summary]
The receiving device according to the disclosure outline includes two or more receiving antennas that receive a block signal including transmission control information and data, two or more receiving systems that process the signals received by each of the two or more antennas, a synthesis processing unit that performs synthesis processing of the signals processed by the two or more receiving systems, and a control unit that controls the synthesis processing unit, and the control unit controls the synthesis processing unit based on whether or not an error has occurred in the transmission control information after the synthesis processing is performed.

In the summary of the disclosure, the receiving device controls the synthesis processing unit based on whether an error occurs in the transmission control information after execution of the synthesis process. With this configuration, the receiving device can appropriately determine the situation in which a diversity effect can be obtained, and can appropriately execute the synthesis process.

[Embodiment]
(Digital wireless transmission system)
A digital wireless transmission system according to an embodiment will be described below. Fig. 1 is a diagram showing a digital wireless transmission system 10 according to an embodiment. As shown in Fig. 1, the digital wireless transmission system includes a transmitting device 100 and a receiving device 200.

In an embodiment, the digital wireless transmission system 10 may be a millimeter wave wireless camera system. The digital wireless transmission system 10 may employ a single carrier (SC)-FDE (single carrier-frequency domain equalization) scheme. The digital wireless transmission system 10 may employ single-input multiple-output (SIMO). A scheme having SC-FDE and SIMO may be referred to as SIMO-SC-FDE. In the following, SIMO-SC-FDE will be mainly described.

Thus, the transmitting device 100 has one transmitting antenna 180, and the receiving device 200 has two or more receiving antennas 280. The processing or configuration related to the signals received by each receiving antenna 280 before the combining process may be referred to as a "system." The combining process may be referred to as diversity combining.

(Transmitting device)
A transmitting device according to an embodiment will be described below. Fig. 2 is a block diagram showing a transmitting device 100 according to an embodiment.

As shown in FIG. 2, the transmitting device 100 has an encoding unit 110, an interleaving unit 120, a mapping unit 130, a control information generating unit 140, a block configuration unit 150, and an orthogonal modulation unit 160. In FIG. 2, configurations that are less relevant to the disclosure are omitted.

The encoding unit 110 performs encoding of the bit string that constitutes the data to be transmitted. For example, the encoding unit 110 generates an error correction block by adding an error correction code to the bit string. As the error correction code, parity (Low-Density Parity-check Code) can be used. For example, the encoding rate can be 1/2, 2/3, 3/4, or 5/6.

The interleaving unit 120 performs interleaving of bits constituting the bit string output from the encoding unit 110. For example, the interleaving unit 120 may perform interleaving in the time axis direction (hereinafter, time interleaving). Time interleaving is a process of rearranging bits in the time axis direction in units of error correction blocks.

The mapping unit 130 maps the bit string output from the interleaving unit 120 to symbols on the IQ plane based on the modulation method. The IQ plane is a plane defined by an I (In-phase) component and a Q (Quadrature) component. For example, modulation methods that can be used include BPSK (Binary Phase-Shift Keying), QPSK (Quadrature PSK), 8PSK, 16APSK (16 Amplitude PSK), 32APSK, and QAM (Quadrature Amplitude Modulation).

The control information generating unit 140 generates transmission control information (hereinafter, TMCC (Transmission and Multiplexing Configuration Control) information). The TMCC information may be simply referred to as TMCC. The control information generating unit 140 may generate a known signal (hereinafter, UW; Unique Word) used for channel estimation in the receiving device 200. The UW may be referred to as a pilot signal.

For example, as shown in FIG. 3, the TMCC may include bits indicating the modulation method of the data to be transmitted (e.g., b ₀ to b ₂ ), bits indicating the coding rate of the data to be transmitted (e.g., b ₃ to b ₄ ), bits indicating the modulation method of the data of the auxiliary information (e.g., b ₅ ), bits indicating the coding rate of the data of the auxiliary information (e.g., b ₆ to b ₇ ), a frame number (e.g., b ₈ to b ₁₀ ), a block number (e.g., b ₁₁ to b ₁₈ ), and reserves (e.g., b ₁₉ to b ₂₂ ).

Auxiliary information is information transmitted via an AC (Auxiliary Channel). Auxiliary information may simply be referred to as AC. AC is information that accompanies the data to be transmitted, and the content of AC is not particularly limited.

The block number is a number that identifies a block that constitutes a transmission unit. The block may be referred to as an SC-FDE block. The block number may be a number that is assigned consecutively according to the transmission order. The frame number is a number that identifies a frame that is composed of two or more SC-FDE blocks. The frame number may be a number that is assigned consecutively according to the transmission order. The block number and the frame number may be considered to be sequence numbers.

The block configuration unit 150 configures blocks that constitute transmission units based on the signal output from the mapping unit 130 and the information output from the control information generation unit 140. The SC-FDE block may be separated by a guard interval (GI). The GI may be a cyclic prefix (CP). That is, the block configuration unit 150 may add a GI to the SC-FDE block.

For example, as shown in FIG. 4, an SC-FDE block includes a UW, data, a TMCC, and an AC. As described above, the UW is a pilot signal used by the receiving device 200 for channel estimation. The TMCC includes at least a block identification number. The AC is auxiliary information accompanying the data to be transmitted. Here, the modulation methods of the data, the TMCC, and the AC may be different from each other. The coding rates of the data, the TMCC, and the AC may be different from each other. The modulation method of the TMCC may be a differential modulation method such as DBPSK (Differential BPSK) or DQPSK (Differential QPSK).

The orthogonal modulation unit 160 performs DA conversion of the signal output from the block configuration unit 150, and then performs orthogonal modulation of the signal after DA conversion (orthogonal modulation may be performed by digital processing, and then DA conversion may be performed).

(Receiving device)
The receiving device 200 according to the embodiment will be described below. Fig. 5 is a diagram showing the receiving device 200 according to the embodiment.

As shown in FIG. 5, the receiving device 200 has two or more receiving systems 210, a synthesis processing unit 220, an IFFT unit 230, a demapping unit 240, a deinterleaving unit 250, a decoding unit 260, a TMCC detection unit 271, and a control unit 272.

The two or more receiving systems 210 are processing units provided for each receiving antenna 280. The two or more receiving systems 210 process signals received by each of the two or more receiving antennas 280. Since the configuration of each receiving system 210 is the same, the following description focuses on one receiving system 210.

Specifically, as shown in FIG. 6, the reception system 210 has a reception processing unit 211, a TMCC detection unit 212, an FFT unit 213, a channel estimation unit 214, and a noise detection unit 215.

The reception processing unit 211 performs orthogonal demodulation of the signal received from the transmitting device 100, and then performs AD conversion (orthogonal demodulation may be performed by digital processing after AD conversion). The reception processing unit 211 may remove the GI from the time domain signal after orthogonal demodulation. The reception processing unit 211 outputs the time domain signal after orthogonal demodulation for each SC-FDE block.

The TMCC detection unit 212 detects the TMCC from the time domain signal output from the reception processing unit 211. Specifically, the TMCC detection unit 212 identifies at least the block number by demodulating the detected TMCC. The TMCC detection unit 212 may also identify the frame number. The TMCC detection unit 212 may also identify other information elements included in the TMCC. The TMCC detection unit 212 outputs the identified TMCC (hereinafter, pre-synthesis TMCC) to the control unit 270.

The FFT unit 213 applies FFT (Fast Fourier Transform) processing to the time domain signal output from the reception processing unit 211, and converts the time domain signal into a frequency domain signal. The FFT unit 213 outputs the frequency domain signal to the synthesis processing unit 220.

The channel estimation unit 214 identifies a UW from the time domain signal output from the reception processing unit 211, and performs channel estimation based on the UW. Specifically, the channel estimation unit 214 estimates the propagation path characteristics between the transmission antenna 180 and the reception antenna 280, and identifies parameters that indicate the propagation path characteristics. The channel estimation unit 214 outputs the identified parameters to the synthesis processing unit 220.

The noise detection unit 215 identifies the UW from the time domain signal output from the reception processing unit 211, and identifies the noise power based on the UW. The noise detection unit 215 outputs a parameter indicating the identified noise power to the synthesis processing unit 220.

Returning to FIG. 5, the synthesis processing unit 220 synthesizes signals processed by two or more receiving systems 210 (diversity synthesis).

First, the combining processing unit 220 may perform synchronization processing of signals processed by two or more receiving systems 210. The synchronization processing is processing for synchronizing the SC-FDE blocks for each receiving system 210. For example, when processing the n-th SC-FDE block, the combining processing unit 220 may include processing for eliminating the influence of ghosts (multipath) of the n-1-th SC-FDE block using channel information of each receiving system 210 (hereinafter, ghost elimination processing). When channel information for each receiving system 210 is used in the ghost elimination processing, the synchronization processing may be performed for each receiving system 210. When the average value of the channel information of the receiving systems 210 is used in the ghost elimination processing, the synchronization processing may be performed between the receiving systems 210. When the SC-FDE blocks are synchronized by the synchronization processing, the synchronization processing is omitted in subsequent processing.

Secondly, the synthesis processing unit 220 may convert the signals processed by the two or more receiving systems 210 into frequency domain signals and perform an equalization process to equalize the converted frequency domain signals. For example, the synthesis processing unit 220 performs an equalization process to equalize the frequency domain signals output from the FFT unit 213 based on the propagation path characteristics estimated by the channel estimation unit 214 and the noise power identified by the noise detection unit 215. In the equalization process, the equalization weights for equalizing the frequency domain signals may be calculated using the Minimum Mean Squared Error (MMSE) method. The equalization process may include a maximum ratio combining process.

Thirdly, the synthesis processing unit 220 may perform synthesis processing to synthesize signals to which equalization processing has been applied for each reception system 210. For example, the synthesis processing unit 220 performs synthesis processing to synthesize signals equalized by equalization weights for each reception system 210.

The IFFT unit 230 applies IFFT (Inverse Fast Fourier Transform) processing to the frequency domain signal output from the synthesis processing unit 220, and converts the frequency domain signal back into a time domain signal.

The demapping unit 240 demaps the symbols on the IQ plane into bit strings for each carrier in the reverse procedure to that of the mapping unit 130. As a demapping method, hard decision or soft decision may be used. When soft decision is used, bit likelihood for performing LDPC decoding may be calculated.

The deinterleaving unit 250 performs time deinterleaving in the reverse order to that of the interleaving unit 120.

The decoding unit 260 performs decoding of the bit string output from the deinterleaving unit 250 in the reverse procedure to that of the encoding unit 110. That is, the decoding unit 260 performs error correction based on an error correction code (e.g., LDPC parity).

The TMCC detection unit 271 detects the TMCC from the signal output from the synthesis processing unit 220. Specifically, the TMCC detection unit 271 detects the TMCC by applying IFFT processing to the frequency domain signal output from the synthesis processing unit 220. The TMCC detection unit 271 identifies at least the block number by demodulating the detected TMCC. The TMCC detection unit 271 may also identify the frame number. The TMCC detection unit 271 may also identify other information elements included in the TMCC. The TMCC detection unit 271 outputs the identified TMCC (hereinafter, the synthesized TMCC) to the control unit 270.

The control unit 272 controls the synthesis processing unit 220. Specifically, the control unit 272 controls the synthesis processing unit 220 based on whether or not an error occurs in the TMCC after the synthesis process is performed. In other words, the control unit 272 controls the synthesis processing unit 220 based on whether or not an error occurs in the TMCC after synthesis.

The error in the combined TMCC may include an error in which the combined TMCC cannot be identified (or demodulated or received). It may also include an error in which the block numbers included in the combined TMCC are discontinuous. The error in the combined TMCC may also include an error in which the frame numbers included in the combined TMCC are discontinuous.

For example, if an error occurs in the combined TMCC, the control unit 272 may apply a reset process related to the operation of the combination processing unit 220. The reset process may include a process of redoing the synchronization process described above.

The control unit 272 may restrict the execution of the reset process when an error occurs in the pre-combined TMCC for a specific reception system included in the two or more reception systems 210, but an error does not occur in the combined TMCC. In other words, when an error does not occur in the combined TMCC, the control unit 272 does not execute the reset process, regardless of the detection result of the pre-combined TMCC.

Here, the error in the pre-composited TMCC may include an error in which the block numbers included in the pre-composited TMCC are discontinuous. The error in the pre-composited TMCC may include an error in which the frame numbers included in the pre-composited TMCC are discontinuous. The error in the pre-composited TMCC may include an error in which the pre-composited TMCC cannot be identified (or demodulated or received).

The control unit 272 may control the synthesis processing unit 220 to execute synthesis processing without excluding the specified system from the targets of synthesis processing, even if an error in the pre-synthesized TMCC occurs for a specified reception system included in the two or more reception systems 210. However, when an error in the pre-synthesized TMCC occurs for a specified reception system included in the two or more reception systems 210, the control unit 272 may control the synthesis processing unit 220 to execute synthesis processing by excluding the specified system from the targets of synthesis processing.

The control operations of the control unit 272 described above may be represented by the matrix shown in FIG. 7. As shown in FIG. 7, the control operations of the control unit 272 can be categorized into types No. 1 to No. 4 according to the pre-combination TMCC and the post-combination TMCC. "○" indicates that no TMCC error has occurred, and "×" indicates that a TMCC error has occurred.

As shown in No. 1, if no errors occur in either the pre-combination TMCC or the combined TMCC, the control unit 272 controls the combination processing unit 220 to continue the combination process.

As shown in No. 2, when no error occurs in the pre-combination TMCC but an error occurs in the combined TMCC, the combining processing unit 220 is controlled to execute a reset process. In such a case, it may be determined that the decoding of the SC-FDE block itself is an error. Alternatively, the control unit 272 may control the combining processing unit 220 to execute a combining process using a signal output from a reception system in which no TMCC error occurs.

As shown in No. 3, if an error occurs in the pre-combination TMCC but no error occurs in the combined TMCC, the combination processing unit 220 is controlled to continue the combination processing without performing a reset process. In such a case, the control unit 272 may control the combination processing unit 220 to perform the combination processing without excluding the specified reception system in which the TMCC error occurs. Alternatively, the control unit 272 may control the combination processing unit 220 to perform the combination processing, excluding the specified reception system in which the TMCC error occurs.

As shown in No. 4, when an error occurs in both the pre-combination TMCC and the combined TMCC, the control unit 272 controls the combination processing unit 220 to execute a reset process. In such a case, it may be determined that the decoding of the SC-FDE block itself is an error.

(Action and Effects)
In the embodiment, the receiving device 200 controls the synthesis processing unit 220 based on whether an error occurs in the synthesized TMCC. With such a configuration, the receiving device 200 can appropriately determine a situation in which a diversity effect can be obtained, and can appropriately execute the synthesis processing 220.

For example, the receiving device 200 may apply a reset process for the operation of the synthesis processing unit 220 when an error occurs in the synthesized TMCC. With this configuration, the reset process can be appropriately applied in a situation where the diversity effect cannot be obtained.

The receiving device 200 may limit the execution of the reset process when a pre-combination TMCC error occurs for a specific receiving system included in two or more receiving systems 210, but no post-combination TMCC error occurs. With this configuration, in a situation where a pre-combination TMCC error temporarily occurs, the combination process of the combination processing unit 220 can be continued, thereby reducing the possibility of inefficient redoing of the synchronization process.

The receiving device 200 may control the synthesis processing unit 220 to execute synthesis processing without excluding a specific reception system even if an error occurs in the pre-synthesized TMCC for the specific reception system included in the two or more reception systems 210. With this configuration, in a situation where even a small amount of diversity effect can be obtained, the diversity effect can be appropriately obtained by continuing the synthesis processing of the synthesis processing unit 220.

[Other embodiments]
Although the present invention has been described by the above disclosure, the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art.

Although not specifically mentioned in the above disclosure, the receiving device 200 (TMCC detection unit 212 and TMCC detection unit 271) may demodulate the TMCC by differential demodulation. In such a case, the receiving device 200 can demodulate the TMCC without requiring a synchronization signal or the like.

Although not specifically mentioned in the above disclosure, a case where SIMO-SC-FDE is used has been described. However, the above disclosure is not limited to this. For example, the above disclosure may be applied to MIMO (Multiple-Input Multiple-Output). The above disclosure may be used in an MC (Multiple Carrier) system. In these cases, it may be assumed that FDE is used.

Although not specifically mentioned in the above disclosure, a program may be provided that causes a computer to execute each process performed by the transmitting device 100 and the receiving device 200. The program may also be recorded on a computer-readable medium. Using the computer-readable medium, it is possible to install the program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM.

Alternatively, a chip may be provided that is configured with a memory that stores programs for executing the processes performed by the transmitting device 100 and the receiving device 200, and a processor that executes the programs stored in the memory.

10...digital wireless transmission system, 100...transmitting device, 110...encoding section, 120...interleaving section, 130...mapping section, 140...control information generating section, 150...block configuration section, 160...orthogonal modulation section, 180...transmitting antenna, 200...receiving device, 210...receiving system, 211...receiving processing section, 212...TMCC detection section, 213...FFT section, 214...channel estimation section, 215...noise detection section, 220...synthesis processing section, 230...IFFT section, 240...deinterleaving section, 250...decoding section, 260...TMCC detection section, 270...control section, 280...receiving antenna

Claims (4)

Two or more receiving antennas for receiving a signal of a block including transmission control information and data;
Two or more receiving systems each processing a signal received by each of the two or more antennas;
a synthesis processing unit that executes synthesis processing of signals processed by the two or more reception systems;
A control unit that controls the synthesis processing unit,
The control unit controls the synthesis processing unit based on whether an error occurs in the transmission control information after the synthesis process is performed ,
the control unit executes a reset process for the operation of the synthesis processing unit when an error occurs in the transmission control information after the synthesis process is executed;
The control unit of the receiving device limits the execution of the reset process when an error occurs in the transmission control information for a specific receiving system included in the two or more receiving systems, but no error occurs in the transmission control information after the synthesis process is executed . The receiving device according to claim 1, wherein the control unit controls the synthesis processing unit to execute the synthesis process without excluding a specific receiving system included in the two or more receiving systems from the synthesis process even if an error in the transmission control information occurs for the specific receiving system. 3. The receiving device according to claim 1, wherein the synthesis processing unit converts the signals processed by the two or more receiving systems into signals in a frequency domain, and performs an equalization process for equalizing the converted frequency domain signals. A receiving device as described in any one of claims 1 to 3, wherein the error in the transmission control information after the synthesis process is executed includes at least one of an error in which the transmission control information cannot be identified after the synthesis process is executed, an error in which the block numbers included in the transmission control information after the synthesis process is executed are discontinuous, and an error in which the frame numbers included in the transmission control information after the synthesis process is executed are discontinuous.

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