WO2007126073A1 - 受信機、送信機、伝送システム、及び伝送方法 - Google Patents
受信機、送信機、伝送システム、及び伝送方法 Download PDFInfo
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- WO2007126073A1 WO2007126073A1 PCT/JP2007/059232 JP2007059232W WO2007126073A1 WO 2007126073 A1 WO2007126073 A1 WO 2007126073A1 JP 2007059232 W JP2007059232 W JP 2007059232W WO 2007126073 A1 WO2007126073 A1 WO 2007126073A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03159—Arrangements for removing intersymbol interference operating in the frequency domain
Definitions
- Receiver transmitter, transmission system, and transmission method
- the present invention relates to a receiver, a transmitter, a transmission system, and a transmission method in a block transmission scheme that performs equalization processing in units of blocks. More specifically, the present invention relates to urban noise in a block transmission scheme. Thus, the present invention relates to a technique for reducing the influence of noise whose amplitude increases instantaneously.
- the block transmission method transmits a signal block composed of a plurality of symbol powers, and performs equalization and demodulation processing for each block on the receiving side.
- Block / IS transmission schemes include OFDM (Orthogonal Frequency Division Multiplexing) scheme and SC-CP (Single Carrier block transmission with Cyclic Prefix) scheme that applies cyclic prefix to single carrier modulation scheme. And so on.
- OFDM Orthogonal Frequency Division Multiplexing
- SC-CP Single Carrier block transmission with Cyclic Prefix
- the SC-CP scheme is a transmission scheme in which a cyclic prefix is inserted in a guard interval (Guard Interval) for transmission, and equalization is performed on the receiving side in the discrete frequency domain.
- Guard Interval Guard Interval
- equalization refers to processing that removes the influence of the received signal power signal transmission path.
- the SC-CP method uses a discrete frequency domain equalizer. This is achieved by performing discrete Fourier transform on the received signal vector after CP removal, multiplying each frequency component by a weight in the transform domain, and returning the signal to the time domain signal again by inverse discrete Fourier transform. It is a vessel.
- the conventional transmission method has a relatively small amplitude compared to the received signal and is distributed over the entire signal. It has been developed in consideration of dealing with white Gaussian noise.
- impulsive noise (see Fig. 18) with instantaneous power larger than the received signal, such as urban noise, behaves differently from the white Gaussian noise model. For this reason, in the presence of noise such as urban noise, conventional transmission systems often cannot demodulate well. Moreover, the urban noise is locally present in the block in time and has a large amplitude. As a result, during the frequency domain equalization process, the entire frequency band is adversely affected and the equalization process cannot be performed well.
- noise having a larger instantaneous power than the received signal becomes a serious factor that makes reception impossible or reduces the transmission error rate.
- an object of the present invention is to provide a new technique for reducing the influence of noise having an instantaneous power larger than that of a received signal.
- the present invention relates to a block transmission system receiver that receives a signal block transmitted from a transmission side and performs equalization processing for each received signal block, and exists locally in the received signal block.
- a local noise detection unit that detects local noise having a larger amplitude than the signal, and a local noise that generates a local noise disappearing reception signal block in which a signal in a range where local noise exists in the reception signal block is lost together with the local noise.
- An erasure processing unit and an equalizer that performs equalization processing based on the local noise erasure reception signal block are provided.
- the receiver eliminates local noise even if it exists. Then, equalization processing is performed based on the received signal block from which local noise has disappeared. Therefore, adverse effects of local noise on a wide frequency range can be reduced during equalization processing.
- the local noise detecting means detects a range in which the signal amplitude of the received signal block exceeds a predetermined threshold as local noise.
- the local noise detecting means detects at least a position and a noise width of the local noise in the received signal block.
- ⁇ is Plock long.
- ⁇ is a diagonal matrix having ⁇ admir,..., J as diagonal components, and is given by the following equation.
- ⁇ - ⁇ ⁇ is the variance of the noise component of r. Is the variance of the signal component of r '.
- P is the local noise width.
- E is a complex conjugate.
- An erasure signal replica generation unit that generates an erasure signal replica representing a signal component lost together with local noise when generating the local noise erasure reception signal block based on the local noise erasure reception signal block;
- the equalizer preferably performs an equalization process on the lost signal supplemented received signal block in which the lost received signal block is supplemented with the lost signal replica.
- Equalization processing is performed on the erasure signal supplemented reception signal block obtained by adding the erasure signal replica representing the signal component lost together with the local noise at the time of generating the local noise erasure reception signal block to the erasure reception signal block. For example, adverse effects caused by the local noise elimination process can be reduced.
- a transmission signal block temporary estimation unit that temporarily estimates a transmission signal block transmitted from a transmission side on the basis of the local noise lost reception signal block is further provided, and the lost signal replica generation unit includes the lost signal signal Preferably, the replica is generated based on the temporarily estimated transmission signal block.
- the lost signal replica generation unit generates a replica of the lost signal based on the lost transmission signal defined below.
- the signal that is actually required is an erasure transmission signal defined by the following equation. By using this, the calculation can be made more efficient.
- the erasure signal replica generation unit calculates an erasure reception signal obtained by removing components other than the erasure transmission signal from the temporarily estimated transmission signal block from the local noise erasure reception signal block, Preferably, the lost transmission signal is restored based on the lost received signal, and a replica of the lost signal is generated based on the restored lost transmission signal.
- the lost transmission signal has relatively low power and is relatively uncertain. Therefore, an erasure reception signal obtained by removing from the local noise erasure reception signal block components other than the erasure transmission signal (relatively probable components) of the temporarily estimated transmission signal block is calculated. And based on the lost received signal, The accuracy is improved by restoring the lost transmission signal.
- the equalizer preferably performs equalization processing according to the following equation.
- Is the variance of the transmitted signal amplitude is the variance of the thermal noise amplitude of the receiver ⁇ is the local noise width. : Is the complex conjugate of / ⁇ .
- the receiver is configured to be able to transmit information on the noise width of local noise and / or the order of the transfer function of the signal transmission path to the transmitter. Since the transmitter can receive information on the noise width of local noise and / or the order of the transfer function of the signal transmission path from the receiver, an appropriate delay amount can be given to the transmission signal in the transmitter.
- the present invention relating to a transmitter is a transmitter for transmitting to a receiver a signal block that can be subjected to equalization processing by removing local noise from the received signal block.
- a delay generation unit that generates a delay signal of the signal block to be transmitted so that the order of the transfer function of the signal transmission path recognized by the machine is larger than the order of the transfer function of the actual transmission path; It is characterized by that.
- the receiver When the delayed signal of the transmitted signal block is generated so that the order recognized by the receiver is larger than the order of the actual transmission path, the receiver eliminates the signal component lost by the local noise elimination processing. Can be restored.
- the delay generation unit is configured by a plurality of antennas that transmit the transmission signal block from different positions so that the order of the transfer function of the signal transmission path recognized by the receiver increases. It's preferable to [0020] Further, the delay generation unit multiplexes and transmits the delayed transmission signal block having a delay in the transmission signal block so that the order of the transmission function of the signal transmission path recognized by the receiver is increased. It can be configured and played.
- the delay D generated by the delay generation unit Preferably satisfies P ⁇ D + L.
- the transmitter is capable of receiving information on the noise width of the local noise and / or the order of the transfer function of the signal transmission path included in the received signal block, and the signal detected by the receiver.
- a delay generation unit that generates a delay signal of the signal block to be transmitted so that the order of the transfer function of the transmission path is larger than the order of the transfer function of the actual transmission path, and the delay generation unit It is preferable to generate a delay signal having a delay amount according to information on the local noise width and / or transfer function order transmitted from the machine.
- the present invention relating to a block transmission system is a block transmission system in which a signal block transmitted from a transmission side is received at a reception side and equalization processing is performed for each reception signal block.
- a local noise detection unit for detecting local noise having a larger amplitude than the signal, and a local noise disappearing received signal block in which a signal in a range where the local noise exists in the received signal block is lost together with the local noise.
- a local noise elimination processing unit to be generated and an equalizer that performs equalization processing based on the local noise elimination reception signal block are provided.
- the present invention related to the block transmission method is a block transmission method in which a signal block transmitted from the transmission side is received at the reception side and equalization processing is performed for each received signal block. To detect local noise that is present and has a larger amplitude than the signal, and to generate a received signal block that eliminates the signal in the received signal block in the range where the local noise exists together with the local noise. And a step of performing equalization processing based on the local noise loss received signal block.
- FIG. 1 is a basic configuration diagram of an SC-CP transmission system.
- FIG. 2 Data structure in SC-CP transmission system.
- FIG. 3 is a configuration diagram of a transmission system according to the first embodiment.
- FIG. 4 is a diagram illustrating the principle of local noise detection.
- FIG. 5 is a diagram showing received signal blocks before and after the disappearance of local noise.
- FIG. 6 is a block diagram of an equalizer.
- FIG. 7 is a configuration diagram of a transmission system according to a second embodiment.
- FIG. 8 is a block diagram showing an erasure signal replica generation unit according to a third embodiment.
- FIG. 9 is a diagram showing the characteristics of a local noise lost received signal block and a lost signal replica.
- FIG. 10 is a proof diagram of relational expression A.
- FIG. 11 is an explanatory diagram for deriving the relational expression A force deformation formula B and deformation formula C.
- FIG. 12 is a configuration diagram of a transmission system according to a fourth embodiment.
- FIG. 13 is a principle diagram showing that a signal is restored even when local noise elimination processing is performed.
- FIG. 14 is a diagram showing a transmitter of a transmission system according to a fifth embodiment.
- FIG. 15 is a configuration diagram of a transmission system according to a fifth embodiment.
- FIG. 18 is a diagram showing local noise.
- FIG. 1 shows the basic configuration of the SC-CP transmission system.
- This transmission system includes a transmitter 10 and a receiver 20, and a signal transmitted from the transmitter 10 is received by the receiver 20 via a transmission path 30.
- FIG. 2 shows a transmission data format (frame structure) in the transmission system.
- a data block (hereinafter sometimes simply referred to as a block) is a block body part consisting of multiple complex baseband signals (M symbols) plus a cyclic prefix (K symbols). .
- the cyclic prefix is sometimes simply referred to as CP.
- CP when referring to a symbol, it usually means the power of assigning multiple bits to one symbol. Here, only one bit may be harmed to one symbol.
- the preamble block (hereinafter sometimes simply referred to as a preamble) refers to a known signal added to the head of a frame.
- the preamble is used to estimate the frequency transfer function in single carrier block transmission, and is also used to synchronize the clock and frequency at the receiver.
- PN Physical Random Noise
- the chirp signal is a "sine wave whose frequency increases linearly" and is described in the literature [J. Cioffi and J. A.
- the pilot signal is a known signal carried in a data block. In the single carrier block transmission system, it is used to estimate the frequency transfer function. It can also be used to synchronize clocks and frequencies at the receiver.
- the literature [K. Hayashi and b. Hara, A New spatio-Temporal Equalization Method Based on Estimated Channel Response, IEEE Transactoins on Vehicular Technology, Vol. 50, No.5, p.1250-1259, 2001.]
- Fig. 3 shows an example of using a PN sequence suppressed for the data channel.
- CP is obtained by copying the last K (K ⁇ M) components of the block main body to the head of the block main body in the same order.
- K K ⁇ M
- Inter-block interference (hereinafter also referred to as IBI) is caused by the delay signal of the previous block generated in the signal transmission path overlapping the signal of the current block.
- the transmitter 10 blocks transmission data for each M symbols (block body part generation process).
- Expression (1) represents the block body s (n).
- n is a number assigned to each block, and n-1 is the number of the previous block, where n is the number of the current block.
- the transmitter 10 adds CP to the block main body represented by the formula (1) to generate a block with CP.
- Equation (2) shows CP addition processing.
- the transmitter 10 modulates and transmits this CP-equipped block.
- T represents the last K components of the block body s (n) as they are.
- Equation (3) Represents the operation of copying to the top in the order of, specifically, the operation represented by Equation (3).
- the receiver 20 includes a transfer function estimator 21 for the transmission line 30.
- the transfer function is estimated by preamble or pilot.
- the estimated transfer function is provided to the equalizer 23 for equalization processing of the received signal block.
- the transfer function estimation can be performed only with the preamble at the beginning of the frame, the transmission function that changes momentarily can be obtained by updating (correcting) the transfer function estimated by the pilot signal synthesized in the block.
- the transfer function of the road can be estimated more accurately.
- the receiver 20 also includes an order determination unit 22 for the transmission line 30, and the order determination unit 22 determines the order L of the transmission line 30.
- the determination of the order L may be performed by Fourier transform (FFT) similarly to the transfer function estimation unit 21, or may be performed by an order determination algorithm such as AIC (AKAIE Information Criterion) or MDL (Minimum Description Length).
- FFT Fourier transform
- AIC AKAIE Information Criterion
- MDL Minimum Description Length
- the order by Fourier transform it may be obtained from the maximum delay of the signal when the thermal noise part other than the signal is removed by a predetermined threshold based on the Fourier transform result.
- the obtained order L is used for various calculations in the receiver 20.
- Equation (4) the received signal block in the receiver 20 is expressed as shown in Equation (4).
- H can be expressed as in Equation (5).
- H be the two sub-matrices H and H of (M + K) X (M + K)
- the received signal block is
- Equation (8) HJcp s (nl) + H 0 T CP s ( ⁇ ) + n Matrix size: (T + Zr) X 1 (8)
- the first term on the right side of Equation (8) is a signal component from the (n_l) -th transmission signal block (previous block) and represents the inter-block interference (IBI) component.
- the receiver 20 performs processing for removing the CP from the received block. This can be expressed by equation (9).
- Equation (9) R represents an operation for removing CP, and the CP removal operation is represented by Equation (10). ).
- a matrix having a structure such as equation (12) is called a circulant matrix (Circulant Matrix), and "a unitary similarity transformation is possible using a Discrete Fourie Transform (DFT) matrix.”
- DFT Discrete Fourie Transform
- O ff O l M (I is the identity matrix of MXM).
- the received signal r (n) after CP removal can be written as follows.
- the frequency domain equalization process performed in the equalizer 23 performs discrete Fourier transform on the received signal block after CP removal, multiplies the weight for each frequency component in the transform domain, and again by discrete Fourier transform. Equalization is achieved by returning to the time domain signal. For this reason, the presence of burst-like local noise that affects a wide frequency band is adversely affected in a wide frequency band during frequency domain equalization.
- the equalizer output signal is as follows.
- L ⁇ , ⁇ , ⁇ is the discrete Fourier of the impulse response of the transmission line from the equation (14).
- Noise enhancement means “the response of the channel at a certain frequency ⁇ is 0 or 0 i
- the transmission signal block in which the influence of the transmission path is reduced can be reproduced in the receiver 20.
- the signal determination unit 24 can determine the symbol S.
- the signal determination unit 24 is for determining a symbol based on a predetermined reference (threshold value) because the phase and amplitude are not constant due to the influence of noise or the like even if the signals indicate the same symbol. is there.
- FIG. 3 shows a block transmission system according to the first embodiment of the present invention.
- burst noise local noise that exists locally in the received signal block and has a larger amplitude than the signal
- the receiver 20 includes a local noise detection unit 25 for detecting local noise included in the received signal block.
- the local noise detector 25 detects a signal having a signal amplitude larger than a predetermined threshold as local noise (burst noise).
- the receiver 10 includes a local noise elimination processing unit 27 that generates a local noise loss reception signal block in which a signal in a range where local noise exists in the reception signal block is lost together with the local noise. ing.
- a local noise elimination processing unit 27 that generates a local noise loss reception signal block in which a signal in a range where local noise exists in the reception signal block is lost together with the local noise.
- the threshold value for detecting local noise is set to a value larger than the normal signal amplitude of the received signal block.
- the threshold is preferably 20 dB to 30 dB or more larger than the normal signal amplitude of the received signal block.
- the local noise detector 25 detects the position of the local noise in the received signal block and its noise width.
- the position of the local noise is detected as the noise start position i
- the noise width is detected as the width (time width) P in which noise exists from the noise start position i.
- the method of specifying the range where the local noise exists is not limited to i and P described above.
- the local noise range may be specified at the start and end positions of the local noise.
- FIG. 5 (a) shows a block before the local noise is eliminated by the local noise elimination processing unit 27, and FIG. 5 (b) shows a block after the local noise is eliminated.
- the local noise elimination processing unit 27 sets all the signals during the time when the detected local noise exists to zero. In other words, symbols (P symbols from position i) in the range where local noise exists in the received signal block are 0. Although local received signal components (data signals) in the range where local noise exists are also lost by the local noise elimination process, local noise that adversely affects a wide frequency range in the equalization process can be removed.
- the received signal block (local noise eliminated received signal block) r 'after the local noise eliminated process is mathematically expressed as follows.
- the local noise is detected and the local noise is eliminated for the block before removing the CP.
- Equation (8) which represents a received signal that does not consider local noise
- Equation (8) becomes Equation (20) when local noise is considered.
- the received signal block before the local noise elimination process is expressed as in equation (20).
- Equation (20) the local noise is assumed to be burst-like noise having a large amplitude over a number of consecutive complex baseband signal sections.
- the equalizer 23 performs equalization processing in the frequency domain on the received block of local noise loss obtained as described above, it has an adverse effect on a wide frequency domain. Since the local noise has disappeared, the error rate can be improved.
- a propagation delay occurs in the normal transmission line 30, and due to the presence of such a propagation delay signal, the original data signal (disappearance signal) that has disappeared due to local noise naturally occurs. Restored. In other words, in a transmission environment where an appropriate delay signal exists, the lost signal can be restored by the receiver 20, and accurate transmission is realized. Details of this point will be described later.
- the equalizer 23 has a structure as shown in FIG. 6 and performs the processing of the equation (23).
- D is a DFT matrix represented by Expression (15).
- ⁇ is a diagonal matrix having diagonal components when the weight of the equalizer 23 in the discrete frequency domain is ⁇ , ⁇ , ⁇ .
- the weights ⁇ ,..., ⁇ Of the equalizer 23 may use Equation (18) or Equation (19), but Equation (24) is more desirable.
- ⁇ 0 M- ⁇ ⁇ ⁇ is the variance of the received signal r (the noise component of P ).
- Equation (24) eliminates local noise in the MMSE equalizer weight shown in Equation (19). This shows the MMSE equalizer weight for the received signal block of the local noise loss that reflects the effect of this.
- the equalizer weight more suitable for the received block of the local noise disappears than the conventional MMSE equalizer weight of the equation (19).
- the characteristics are improved compared to the case of using MMSE equalizer weights.
- FIG. 7 shows a transmission system according to the second embodiment.
- points that are not particularly described are the same as those in the transmission system of FIG. 1 and the transmission system according to the first embodiment.
- the receiver 20 of the second embodiment performs equalization processing based on the local noise loss received signal block.
- the equalization processing is directly performed on the local noise lost received signal block.
- the receiver 20 of the second embodiment is different from the local noise lost received signal block. It is configured to perform equalization after further processing.
- the receiver 20 of the second embodiment includes a transmission signal block temporary estimation unit 28 and an erasure signal replica generation unit 29a. Then, the transmission signal block temporary estimation unit 28 and the erasure signal replica generation unit 29a generate a replica of the signal component (erasure signal) that has been deleted in the received signal power during the local noise elimination process. Then, in the receiver 20 of the second embodiment, this lost signal replica is added to the local noise lost received signal block expressed by Equation (21) to generate a lost signal supplemented received signal block.
- the lost signal supplement received signal block can perform better equalization processing than the local noise lost received signal block because the lost signal replica is supplemented. Also, in the erasure signal supplement received signal block, the conventional equalizer weight as shown in Equation (18) and Equation (19) is used instead of the equalizer weight that requires a complicated operation as shown in Equation (24). Since the processing can be performed, the computation can be simplified (speeded up).
- the lost signal replica generation unit 29a estimates a replica of this lost signal. Then, the receiver 20 adds the erasure signal replica to the local noise erasure reception signal block!: '(N) represented by the equation (25), and adds the erasure signal supplement reception signal block r "(n). Generate.
- the erasure signal supplemented reception signal block r ′′ (n) is expressed by the equation in the first row of the equation (27).
- the erasure signal supplement reception signal block is received without being affected by local noise. It is almost the same as the signal block (the second row of Equation (27)) (see also Equation (16) and Equation (13)).
- s (n) is the estimated value of the transmitted signal block s (n)
- the received signal block with the erasure signal supplement is substantially equal to the received signal block that is not affected by the local noise, so that the conventional equalizer weight as shown in Equation (18) and Equation (19) is used. Equalization can be performed with the equalizer 23.
- the transmission signal block temporary estimation unit 28 calculates the estimated value of the transmission signal block s (n) as shown in Expression (28).
- the estimated value of the transmission signal block s (n) obtained by Equation (28) is the estimated transmission signal block calculated by Equation (23) (the local noise-erased received signal block is equal to the weight of Equation (24), etc.) That has been subjected to signal determination processing is used. That is, the transmission signal block temporary estimation unit 28 in the second embodiment has the same functions as the equalizer 23 and the signal determination unit 24 in the receiver 20 of FIG. 3 (first embodiment).
- equalizer weight for obtaining the estimated value of the transmission signal block s (n) is not limited to that of Equation (24), and other weights may be used.
- the functions of the receiver 20 of the first embodiment are used as transmission signal block estimation values for generating an erasure signal replica.
- the transmission signal block estimated by the generator 23 and the signal determination unit 24) is used.
- FIG. 8 shows a transmission signal block temporary estimation unit 28 and an erasure signal replica generation unit 29b in the receiver 20 of the transmission system according to the third embodiment.
- points that are not particularly described are the same as those of the transmission system of FIGS. 1 and 7 and the transmission system according to the first and second embodiments.
- the receiver 20 of the third embodiment includes an erasure signal replica generation unit 29b that is an improvement of the erasure signal replica generation unit 29a of the second embodiment.
- FIG. 7 is referred to when necessary in the description of the third embodiment.
- Equation (21) is illustrated as shown in FIG. In the figure, the diagram showing the matrix PC is defined by equation (12).
- the range of the matrix component in which h exists is indicated by diagonal lines, and the range of the matrix component 0 is indicated by white background. Furthermore, in the figure showing the matrix P C
- the part is 0 range by P.
- Equation (28) the estimated value of the transmission signal block s (n) is calculated directly from the local noise loss received signal block (n), and the estimated value power loss transmission signal s sub is calculated. Even if it is extracted, sufficient accuracy cannot be obtained.
- Equation (26) is illustrated as in FIG. 9 (b). In the figure, the diagram showing matrix C is defined by equation (12).
- a value in the vicinity of a symbol that is lost by the local noise loss process (not the lost transmission signal) is not the estimated value of the entire transmission signal block.
- the estimated value (reconstructed value) of) is sufficient, and using this value can speed up the calculation.
- the number of symbols of the lost transmission signal is a value obtained by adding the order L of the transfer function to the local noise length P.
- Equations (29) and (30) below are used to generate an erasure signal replica using the characteristics of the erasure signal replica shown in Fig. 9 (b).
- the lost signal replica which is a partial estimate of the transmitted signal block, is used to obtain the lost signal replica (Eq. (30)).
- the lost transmission signal is calculated by the formula (30a) (30b) c
- relational expression A which is the premise for explanation, will be explained.
- the first term on the left side of relational expression A shown in Fig. 10 indicates the theoretical value (thermal noise is 0) of the local noise-erased received signal block.
- the second term on the left-hand side of relational expression A is the component of the transmitted signal s other than the lost transmitted signal s SUB (see Fig. 9 (a)) that has an effect C corresponding to the transfer function of the transmission line 30.
- the defined signal is called an “erased received signal”.
- the lost received signal is the theoretical value of the signal when the lost transmission signal is received by the receiver 20 (thermal noise is 0).
- relational expression A becomes an erased received signal when the component other than the lost transmitted signal s SUB that has been affected by the signal transmission path C is removed from the local noise lost received signal block. Show me that.
- the erasure reception signal can be obtained by calculating the expression on the left side of the relational expression A.
- the left side of the relational expression A includes the transmission signal transmitted from the transmitter 10, but in order to calculate the left side of the relational expression A with the receiver 20, the transmission signal block temporary estimation unit 28 of the receiver 20 Using the estimated transmission signal block (Equation (28)) temporarily estimated in
- P Cs in the first term on the left side of relational expression A is the received local noise loss received signal.
- the left side of the relational expression A is expressed as a modified expression B shown in FIG. 11, which is almost equal to the erasure reception signal (the right side of the relational expression A).
- Equation (33) is a summary of the above.
- the lost received signal can be extracted by the calculation of Equation (33).
- the calculation of equation (33) is performed by erasure reception signal extraction unit 29b-1.
- the restoration value of the lost transmission signal s sub can be obtained by the equations (30a) (31) (32).
- the lost transmission signal s sub is restored by the lost transmission signal restoration unit 29b-2 of the receiver 20 (see FIG. 8).
- Equation (30a) is based on the modified equation C in the drawing, which is a simplified version of the modified equation B in FIG.
- the modification B can be simplified to the modification C.
- the row size is getting smaller, so the computation can be sped up.
- Equation (32) indicates that the signal required as the erasure reception signal submatrix in Equation (30) differs depending on the local noise position i.
- the lost received signal submatrix is defined.
- the lost transmission signal restoration value obtained in equation (30a) can be applied to equation (29). In this way, the lost transmission signal restoration value rearrangement process is performed. This rearrangement process is performed by the lost transmission signal rearrangement unit 29b-3 of the receiver 20 (see FIG. 8).
- the generated erasure signal replica is added to the local noise erasure reception signal block to generate an erasure signal supplement reception signal block! ⁇ ( ⁇ ).
- Eliminating signal supplement The equalizer 23 that performs equalization processing on the received signal block r "(n) performs equalization with the weights shown in Equation (34).
- the weight of equation (34) is a coefficient suitable for the received signal block r "(n) supplemented with the erasure signal, and can perform good equalization.
- the weight of equation (34) Can also be used for the equalizer 23 for equalizing the erasure signal supplement received signal block r ′′ (n) of the second embodiment.
- the order determined by the order determination unit 22 of the receiver 20 is increased by transmitting the transmission signal from the plurality of antennas 10a and 10b of the transmitter 10. It is what I did.
- points that are not particularly described are the same as those in the transmission system in FIG. 1 and the transmission systems in the first to third embodiments.
- the transmission path A1 from the first antenna 10a to the receiver 20 and the transmission path B 1 from the second antenna 10b to the receiver 20 are different transmission paths. Accordingly, even if the same transmission signal is transmitted from the transmitter 10, the first reception signal transmitted from the first antenna 10a and received by the receiver 20 and the first reception signal transmitted from the second antenna 10b and received by the receiver 20 are received. A propagation delay D occurs between the second received signal and the received signal.
- the antennas 10a and 10b constitute a transmission signal delay generation unit.
- the propagation delay D due to the antennas 10a and 10b is an artificial propagation delay caused by a plurality of antennas in addition to the original propagation delay L of the transmission path 30. That is, the propagation delay (order) L1 detected by the order determination unit 22 of the receiver 20 is (D + L).
- both signals have a time shift due to the propagation delay L. Therefore, if there is local noise, the signal that has passed through transmission path A has the fifth While the symbols and 6th symbol are lost, the 3rd and 4th symbols are lost in the signal passing through transmission path B.
- the third and fourth symbols are recovered by the signal that has passed through the transmission path A, and the fifth and sixth symbols are recovered from the signal that has passed through the transmission path B. .
- the propagation delay L of the transmission line is larger than the time width P of local noise (P ⁇ L).
- the antenna position differs from the original transmission path propagation delay L.
- Propagation delay D is added. Therefore, the delay amount (order of the transfer function) viewed from the receiver 20 is D + L. Therefore, if the delay amount is set appropriately depending on the positions of the antennas 10a and 10b, even if P> L, P ⁇ D + L can be achieved, and signal restoration can be performed appropriately.
- D + L is preferably smaller than CP length K.
- position of antennas 10a and 10b is set so that P ⁇ D + L It is preferable to do this.
- FIG. 14 and 15 show a transmission system according to the fifth embodiment.
- points that are not particularly described are the same as those of the transmission system of FIG. 1 and the transmission systems of the first to fourth embodiments.
- the transmitter 10 shown in FIG. 14 includes a delay generation unit 11 that generates a delayed transmission signal block for multiplexing the transmission signal block.
- the transmitter 10 combines the delayed transmission signal block with the transmission signal block and transmits it to the receiver.
- the propagation delay D by the delay generator 11 is added to the original transmission path propagation delay L.
- the delay amount (order of the transfer function) viewed from the receiver 20 is D + L. Therefore, if the delay amount D is set appropriately, even if P> L, P ⁇ D + L can be achieved, and signal restoration can be performed appropriately.
- D + L is
- the CP length is preferably smaller than K. That is, it is preferable to set the positions of the antennas 10a and 10b so that P ⁇ D + L and K hold.
- the value of the delay amount D in the delay generator 11 may be fixed or variable. By appropriately changing the delay amount according to the condition of the transmission line 30, it is possible to reliably satisfy P ⁇ D + L and restore the signal.
- FIG. 15 shows information for determining the delay D generated by the delay generation unit 11 in the receiver.
- a configuration for acquiring from the 20 side is shown.
- D it is sufficient to have the transmission path order L, local noise width P, and, if necessary, CP length (guard section length) K.
- K is for transmitter 10.
- L and P are detected by the order determination unit 22 and the local noise detection unit 25 of the receiver 20.
- the receiver 20 transmits the order L and the local noise width P to the transmitter 10.
- the delay generation unit 11 of the receiver 10 generates a delayed transmission signal block satisfying P ⁇ D + L or P ⁇ D + L and multiplexes it with the transmission signal block.
- the information sent from the receiver 20 to the transmitter 10 includes the order L and the local noise width.
- Only one of P may be used.
- the order L may be preset in the transmitter 10.
- the local noise width P may be preset in the transmitter 10.
- the order L and the local noise width P are the same values, and the order L and the local noise width P are indirect, such as P—L (minimum required delay D), which does not need to be transmitted to the transmitter 10. May be sent with the information shown.
- Figures 16 and 17 show the BER (Bit Error Rate) characteristics in a 10-path frequency-selective Rayleigh fading channel as simulation results. 16 and 17, the vertical axis represents BERR, and the horizontal axis represents power per bit / white noise power density (E / N). B 0
- FIG. 16 shows a case where the local noise width P is 1
- FIG. 17 shows a case where the local noise width P is 6.
- Transmission path model 10-path frequency selective Rayleigh fading transmission path
- the equalizer 23 having the weight of equation (19) is used.
- the equalizer 23 having the weight of Expression (24) is used.
- the local noise elimination processing function of the present invention is used. If it is a receiver that does not have, but affected by the degree of communication becomes impossible, Example:! Shows in to 3, but has a certain degree of bit error rate, that the force s' s a good performance force.
- Example 2 It can also be seen that the BER performance of Example 2 is better than Example 1 with the conventional weight. Further, Embodiment 3 that equalizes the erasure signal supplement received signal block shows even better BER performance.
- the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
- the present invention can also be used for other communications such as ultrasonic communications as well as wireless communications.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Noise Elimination (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
Description
Claims
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US12/298,710 US8204465B2 (en) | 2006-04-27 | 2007-04-27 | Receiver, transmitter, transmission system, and transmission method |
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JP2006-123743 | 2006-04-27 | ||
JP2006123743A JP5046317B2 (ja) | 2006-04-27 | 2006-04-27 | 受信機、送信機、伝送システム、及び伝送方法 |
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US (1) | US8204465B2 (ja) |
JP (1) | JP5046317B2 (ja) |
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JP6182895B2 (ja) * | 2012-05-01 | 2017-08-23 | 株式会社リコー | 処理装置、処理方法、プログラム及び処理システム |
JP6475946B2 (ja) * | 2014-09-29 | 2019-02-27 | 日本放送協会 | デジタルワイヤレスマイク用受信装置 |
CN108809568B (zh) * | 2017-05-04 | 2023-11-03 | 华为技术有限公司 | 一种信息发送、接收方法及相关设备 |
CN109391443B (zh) * | 2017-08-11 | 2021-12-14 | 华为技术有限公司 | 同步信号块指示及确定方法、网络设备和终端设备 |
US10763984B2 (en) * | 2017-08-18 | 2020-09-01 | Qualcomm Incorporated | Frequency division multiplexing synchronization signals (SS) for wideband operation |
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US20090104876A1 (en) | 2009-04-23 |
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US8204465B2 (en) | 2012-06-19 |
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