WO2009030157A1

WO2009030157A1 - Method, device and system for signal transmission and channel estimation

Info

Publication number: WO2009030157A1
Application number: PCT/CN2008/072177
Authority: WO
Inventors: Hongmei Yao
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-09-03
Filing date: 2008-08-27
Publication date: 2009-03-12
Also published as: CN101383793B; CN101383793A

Abstract

The wireless communications field is related. A method, device and system thereof for channel estimation are disclosed: the channel estimation performance of OFDM system is improved without increasing the pilot overhead. The method includes: demodulating and decoding the virtual pilot channel data; checking the decoded result, if passing the check, restructuring the decoded result into virtual pilot symbols; making channel estimation with virtual pilot symbols and real pilot symbols. Each subcarrier composed in the virtual pilot channel and each subcarrier for transmitting pilot symbol are inter-complemented, for example, cross-arranging equidistantly.

Description

Signal transmission and channel estimation method, device and system thereof

Technical field

Embodiments of the present invention relate to the field of wireless communications, and in particular, to a signal transmission and channel estimation method, apparatus, and system thereof. Background technique

The basis of OFDM (Orthogonal Frequency Division Multiplexing) technology is orthogonal multi-carrier, which can adapt to high-speed mobile environment while effectively increasing the transmission rate. OFDM technology can achieve higher data transmission rates, and has been used in wireless LANs.

The basic principle of OFDM is to transmit high-speed data streams through serial/parallel conversion to several sub-channels with relatively low rates for transmission. Therefore, the symbol period in each sub-channel will increase relatively, which can reduce the number of wireless channels. The time dispersion caused by the delay spread of the path delays the intersymbol interference caused by the system. In addition, due to the introduction of the guard interval, inter-symbol interference due to multipath can be minimized in the case where the guard interval is greater than the maximum multipath delay spread. If the cyclic prefix is used as the guard interval, inter-channel interference due to multipath can also be avoided.

An important issue in OFDM systems is channel estimation, so it is important to improve the performance of channel estimation. Currently, pilot-based channel estimation methods are generally used in OFDM systems. Pilot-based channel estimation generally takes two steps: The first step is pilot estimation, that is, estimating the channel at the pilot position, specifically最小 using least squares criterion, minimum mean square error criterion, etc.; the second step is interpolation estimation, that is, estimating the channel at the non-pilot position, and performing interpolation based on the channel coefficient at the estimated pilot position. The channel coefficients at the non-pilot locations can be either simple linear interpolation or more complex methods such as higher-order interpolation.

Currently, in OFDM systems, there have been some studies using virtual pilot techniques, such as virtual pilot and power-based OFDM channel estimation schemes, which use reliable data as virtual pilots and do these virtual pilots. Power control, Figure 1 shows the solution Schematic diagram of the receiving end of the system. The specific estimation method can be summarized as follows: First, the initial channel estimation is obtained by using the transmitted pilot symbols. Then, using the obtained initial channel estimation information, channel fading compensation is performed on the received signal to obtain a first modulated data symbol. The first modulated data symbol is then demodulated to obtain information bits, and the information bits are again mapped to the second modulation symbol. For all data subcarriers, the Euclidean distance between the first modulated data symbol and the second modulation symbol is calculated. If the Euclidean distance on a subcarrier is within a predefined threshold, then the corresponding one is selected as the virtual pilot. Finally, the real frequency pilot and the virtual pilot are used to accurately estimate the channel frequency response.

In the process of implementing the present invention, the inventors have found that the prior art has at least the following problems: In the OFDM channel estimation scheme based on virtual pilot and power control, user data needs to be demodulated, and according to the received signal and the demodulation symbol Whether the distance threshold value signal can be used as a virtual pilot, and the selected virtual pilot and the actual pilot are combined to complete channel estimation, which cannot ensure the correctness of demodulation on the virtual pilot symbol, thereby The reliability of channel estimation at virtual pilots cannot be guaranteed. In addition, the user terminal performs virtual pilot selection for each data subcarrier, resulting in high complexity. Summary of the invention

Embodiments of the present invention provide a channel estimation method, apparatus, and system thereof, to improve channel estimation reliability of an OFDM system and improve performance of an OFDM system.

The embodiment of the invention further provides a method and a device for transmitting signals based on virtual pilots, so as to reduce the complexity of the virtual pilot technology and improve the performance of the OFDM system.

To achieve the above objective, an embodiment of the present invention provides a channel estimation method, including the following steps:

Demodulating and decoding data of the virtual pilot channel;

Verify the decoding result;

If the check is passed, the decoding result is reconstructed as a virtual pilot symbol; channel estimation is performed using the virtual pilot symbol and the actual pilot symbol.

The embodiment of the invention further provides a channel estimation apparatus, including: a demodulation unit, configured to demodulate data of the virtual pilot channel; and a decoding unit, configured to decode data demodulated by the demodulation unit;

a check unit, configured to verify a decoding result of the decoding unit;

a determining unit, configured to determine whether the decoding result passes the check of the check unit; and an estimating unit, configured to: when the determining unit determines the check by the check unit, reconstruct the decoding result as a virtual pilot symbol, and use the virtual pilot The symbol and the actual pilot symbols are used for channel estimation.

The embodiment of the invention further provides a channel estimation system, including:

a first receiving device, configured to receive user data and pilot data;

a second receiving device, configured to receive data of a virtual pilot channel, where the second receiving device demodulates data of the virtual pilot channel into a virtual pilot symbol, where the virtual pilot symbol is to pass The decoded result of the verification is reconstructed symbol;

The first receiving device includes a channel estimating unit that performs channel estimation according to the virtual pilot symbols and actual pilot symbols.

To achieve the above objective, an embodiment of the present invention provides a signal sending method, including the following steps:

Configuring a virtual pilot channel by a set of reserved subcarriers for transmitting data; assigning the virtual pilot channel to at least one user terminal, and a user terminal with a large signal attenuation preferentially allocating the virtual pilot channel;

Transmitting data in the virtual pilot channel.

To achieve the above objective, an embodiment of the present invention provides a signal transmitting apparatus, including: a channel forming unit, configured to form a set of reserved subcarriers for transmitting data into a virtual pilot channel;

a channel allocation unit, the virtual pilot channel is allocated to at least one user terminal, and the user terminal with a large signal attenuation preferentially allocates the virtual pilot channel;

And a sending unit, configured to send data in the virtual pilot channel.

Compared with the prior art, the main difference and the effect of the embodiment of the present invention are: a virtual pilot channel is formed by a set of reserved subcarriers for transmitting data, and no calculation is required for all data subcarriers by the terminal. After selecting the virtual pilot, the system is reduced. Miscellaneous.

The data of the virtual pilot channel is demodulated and decoded, and the decoding result is verified. If the verification is passed, the decoding result is reconstructed as a virtual pilot symbol, and the virtual pilot symbol and the actual pilot symbol are used for channel estimation. Since the actual pilot symbols are used, not only the actual pilot symbols but also the verified virtual pilot symbols are used, which not only ensures the reliability of the virtual pilot channel estimation, but also improves the channel estimation performance of the OFDM system.

Since the virtual pilot channel is still used for data transmission of the user terminal, the embodiment of the present invention does not increase the overhead of the pilot, and avoids waste of the system time-frequency resource.

The virtual pilot channel is preferentially assigned to a user terminal with a large signal attenuation, such as a user terminal at the cell edge, so that the user terminal located at the center of the cell can perform channel estimation using the virtual pilot. Since the user terminals located in the center of the cell are basically user terminals having a higher working signal-to-noise ratio, the virtual pilot can be made by using the virtual pilot to obtain a more accurate channel estimation by the user terminal located at the center of the cell. The effective utilization of the channel is fully reflected, which can greatly improve the system performance.

Designing the virtual pilot channel to be complementary to the actual pilot channel is equivalent to increasing the pilot density, thereby ensuring improved channel estimation performance.

The virtual pilot channel uses a low-complexity code modulation scheme to ensure that the complexity of the system is improved without increasing the complexity of the channel. DRAWINGS

1 is a schematic diagram of a receiving end of a system in the prior art;

2 (A) is a schematic structural diagram of a channel estimation system according to an embodiment of the present invention; FIG. 2 (B) is a schematic diagram of a structure of a receiving end according to a first embodiment of the present invention; FIG. 3 is a signal transmitting apparatus according to a first embodiment of the present invention; 4 is a flow chart of a channel estimation method according to a first embodiment of the present invention; FIG. 5 is a first schematic diagram of a virtual pilot according to a first embodiment of the present invention; FIG. FIG. 7 is a schematic diagram of a third pattern of a virtual pilot according to a first embodiment of the present invention; FIG. 8 is a schematic diagram of a simulation result of a block error rate according to a first embodiment of the present invention; Figure 9 is a structural diagram of a channel estimating apparatus according to a third embodiment of the present invention. detailed description

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

A first embodiment of the present invention relates to a channel estimation method, including:

First step: demodulating and decoding data of the virtual pilot channel;

The second step: verifying the decoding result;

The third step: if passing the insurance, reconstructing the decoding result as a virtual pilot symbol; Fourth step: performing channel estimation using the virtual pilot symbol and the actual pilot symbol. The virtual pilot symbol in the third step is a symbol that is reconstructed by using the decoding result, the transmission power, and the modulation and coding mode information. The first embodiment of the present invention will be specifically described in conjunction with the structure of the receiver of the present invention.

The embodiment of the present invention provides a channel estimation system, as shown in FIG. 2(A), the system includes a first receiving device 10 for receiving user data and pilot data, and a second receiving device 11 for receiving virtual Data of the pilot channel, which demodulates the data of the virtual pilot channel into virtual pilot symbols, wherein the virtual pilot symbols are symbols reconstructed by the decoded decoding result; The first receiving device 10 includes an estimate.

In the embodiment of the present invention, the basic structure of the receiver is as shown in FIG. 2(B), which includes a receiver 20 and a receiver 21, wherein the receiver 20 is a conventional OFDM receiver, and the receiver 21 is compared with the receiver 20. The OFDM transmit and receive branches need to be modified. The specific modifications include: adding a virtual pilot channel, adding signaling, adding a virtual pilot data receiving channel, and modifying the channel estimation function module.

The embodiment of the invention provides a method for transmitting a signal based on a virtual pilot, which includes the following steps:

In the first step, a virtual pilot signal is formed by a set of reserved subcarriers for transmitting data. In the second step, the virtual pilot channel is allocated to at least one user terminal, and the user terminal with a large signal attenuation preferentially allocates the virtual pilot channel;

In the third step, the data in the virtual pilot channel is transmitted.

According to the foregoing signaling method, the embodiment of the present invention provides a signal transmitting apparatus based on a virtual pilot, as shown in FIG. 3, including:

a channel constituting unit 30, configured to form a set of reserved subcarriers for transmitting data into a virtual pilot channel;

The channel allocation unit 31, the virtual pilot channel is allocated to at least one user terminal, and the user terminal with a large signal attenuation preferentially allocates the virtual pilot channel;

The sending unit 32 is configured to send data in the virtual pilot channel.

The added virtual pilot channel is composed of a set of reserved data subcarriers; the added signaling can enable the system to broadcast related information of the virtual pilot channel to all user terminals; the added virtual pilot data receiving channel enables The user terminal can receive the data of the virtual pilot channel; the input data of the modified channel estimation function module includes the virtual pilot receiving signal, the reconstructed signal, and the CRC (Cyclical Redundancy Check), in addition to the actual pilot receiving signal. The remaining check) is the control signal formed by the error block identification.

In the embodiment of the present invention, the system reserves a part of subcarriers for transmitting data, and the reserved subcarriers for transmitting data constitute a virtual pilot channel, and then allocates the constructed virtual pilot channel to a single. The user terminal divides the virtual pilot channel into groups and distributes them to multiple user terminals. The user terminal allocated with the virtual pilot channel transmits the user data using the allocated virtual pilot channel. Since the virtual pilot channel is still used for data transmission of the user terminal, the embodiment of the present invention does not increase the overhead of the pilot, and avoids waste of the system time-frequency resource. The user terminal to which the virtual pilot channel is allocated is a user terminal with a large signal attenuation. Since the virtual pilot channel is allocated to the user terminal with a large signal attenuation, the user terminal located at the center of the cell can perform channel estimation using the virtual pilot. The user terminals located in the center of the cell are basically user terminals with higher working signal to noise ratios. Therefore, the user terminals located in the center of the cell can obtain more accurate channel estimation by using virtual pilots. The effective utilization of the virtual pilot channel is fully reflected, so that the system performance can be greatly improved.

The system needs to broadcast relevant information of the virtual pilot channel to all user terminals through signaling, and the related information includes the number and location of subcarriers of the virtual pilot channel, the power used by the virtual pilot channel, and the code modulation mode. The power used by the virtual pilot channel is greater than or equal to the power used by the pilot channel; the coded modulation mode of the virtual pilot channel is a coded modulation mode with low complexity, thereby ensuring the complexity of the system while improving channel estimation performance. The degree does not increase much; the coded modulation method used by the virtual pilot channel should be able to easily change the length of the coding block, such as the coding modulation method of the convolutional code. Since the virtual pilot channel is still used for data transmission of the user terminal, the amount of data carried in the virtual pilot channel may be more or less. If the length of the coding block generated by the coding mode is fixed, the amount of data is compared. When the time is small, the required coding block length may not be obtained, so a coding method such as a convolutional code is used, and the coding block length is appropriately set.

The flow of the channel estimation method in the embodiment of the present invention is specifically described below, as shown in FIG.

Step 410: The user terminal demodulates and decodes data of the virtual pilot channel. Specifically, the user terminal acquires related information of the virtual pilot channel from the broadcast information, receives data of the virtual pilot channel according to the acquired information about the virtual pilot channel, and demodulates and decodes the data of the virtual pilot channel. . The user terminal that demodulates and decodes the data of the virtual pilot channel is a user terminal that is not assigned a virtual pilot channel.

Step 420: The user terminal checks the decoded result. That is, the user terminal performs a CRC check on the decoded result.

In step 430, it is determined whether the verification is passed. If the verification is passed, the process proceeds to step 450. If the verification is not passed, the process proceeds to step 440. That is, the user terminal decodes by CRC. If the coded block is correctly decoded, that is, the decoded result passes the check, the process proceeds to step 450. If the coded block is not correctly decoded, that is, the decoded result does not pass the check, then Proceed to step 440.

Step 440: Perform channel estimation using actual pilot symbols. That is, when coding When the block is not correctly decoded, that is, when the virtual pilot data is erroneous, so that the virtual pilot symbols cannot be completely reconstructed, only the actual pilot symbols are used for channel estimation.

Step 450: Reconstruct the decoding result as a virtual pilot symbol. Specifically, after the coded block is correctly decoded, the signal is reconstructed by combining the information about the virtual pilot channel obtained from the broadcast information to obtain a virtual pilot symbol.

Step 460: Perform channel estimation using virtual pilot symbols and actual pilot symbols. That is to say, the received virtual pilot is combined with the actual pilot symbol, and the reconstructed virtual pilot transmission symbol and the known actual pilot transmission symbol information are used together to complete the channel estimation.

It can be seen that since channel estimation is used, not only the actual pilot symbols but also the verified virtual pilot symbols are used, thereby improving the channel estimation performance of the OFDM system, thereby significantly improving the throughput rate of the system. The working threshold of the QAM high-order modulation user of the cell is reduced.

In addition, it is worth mentioning that, in the embodiment of the present invention, the reserved subcarriers for transmitting data (that is, the subcarriers constituting the virtual pilot channel) may be equally spaced from the subcarriers used for transmitting the pilot symbols. The cross-alignment of the virtual pilot channel is designed to be complementary to the actual pilot channel, which is equivalent to an increase in the pilot density, thereby ensuring an improvement in channel estimation performance. The pilot pilot can be used to improve the pilot density in the frequency domain, and can also be used to improve the pilot density in the time domain, or a combination of the two, wherein the case of the virtual pilot and the actual pilot number is 2:1. The virtual pilot pattern can be described in FIG. 5, FIG. 6, and FIG. 7 for the design of three virtual pilots, wherein FIG. 5, FIG. 6, and FIG. 7 D are data; R1 is the first reference symbol; and R2 is the second reference. Symbol; V is a virtual reference symbol:

Figure 5 shows the increase of the pilot density in the time domain. The pilot interval in the time domain becomes smaller, and the pilot interval in the frequency domain does not change. It is suitable for scenes with high moving speed. At this time, the time selectivity of the channel is strong. When the channel estimation is performed, the algorithm of the first time domain and the latter frequency domain can be used to obtain higher gain.

Figure 6 shows the increase of the pilot density in the frequency domain. The pilot interval in the time domain is unchanged, and the pilot interval in the frequency domain becomes smaller. It is suitable for a channel scenario with large delay spread, that is, a channel with strong frequency selectivity, and a channel estimation algorithm using a time domain after the frequency domain can obtain a higher gain.

Figure 7 shows the simultaneous increase of the time domain and frequency domain pilot density. Pilot interval change in time domain Small, the pilot spacing in the frequency domain is also small. This method is suitable for scenarios where the speed of movement and delay are moderate.

5, FIG. 6, and FIG. 7 are three embodiments in which four sub-carriers for transmitting data and four sub-carriers for transmitting pilot symbols are alternately arranged at intervals, and the present invention is not limited to the above three. Any arrangement in which the virtual pilot channel is designed to be complementary to the actual pilot channel is suitable for use in the present invention.

The following is an experimental simulation to compare the difference between the conventional scheme without virtual pilot, the conventional scheme after pilot doubling, and the scheme of virtual pilot of the embodiment of the present invention. This experiment uses an LTE (Long Term Evolution) downlink OFDMA (Orthogonal Frequency Division Multiple Access) access link with a bandwidth of 20 MHz. The simulated channel estimation method uses least squares estimation and first-order interpolation. In the simulation, the virtual pilot symbols are modulated by QPSK (Quadature Phase Shift Keying), and the virtual pilot power is equal to the common pilot power. The various parameters of the experimental simulation are shown in Table 1.

Parameter Value Carrier frequency (GHz) 2.5 Transmission bandwidth (MHz) 20 Subframe duration (ms) 0.5 Sample rate (MHz) 30.72

IFFT Size 2048 Number of Available Subcarriers 1201

Number of CP samples 512 (long CP) Number of OFDM symbols in each TTI 6 channels SCME Suburban Macro Channel coding Turbo r=l/3 Code block size (bit/block) 250 data modulation mode QPSK; 16QAM; 64QAM

UE speed (km/h) 30 pilot pattern first reference signal and second reference signal channel estimation two-dimensional linear interpolation (first step in time domain interpolation, second step in frequency domain interpolation) or

Ideal Estimation Virtual Pilot Parameter Value Channel Coding TbCC r=l/2 Encoding Block Size (bit/block) 400 Data Modulation QPSK Virtual Pilot Number Same as Pilot Number (400) Virtual Pilot Pattern Similar to Pilot Pattern Table 1 The block error rate performance curve of the real-life simulation is shown in Fig. 8. The abscissa in Fig. 8 represents the channel estimation performance; the ordinate represents the coding block error rate. As can be seen from the figure, in the case of the same channel estimation performance, the coding block error rate of the virtual pilot scheme is always lower than that of the conventional scheme without the virtual pilot; in the same coding error block In the case of rate, the channel estimation performance of the virtual pilot scheme is always superior to the channel estimation performance of the conventional scheme without virtual pilot. For example, under 64QAM (Quad Amplitude Modulation) modulation, when the block error rate is 0.001, the performance difference between the performance of the virtual pilot scheme and the performance without the virtual pilot scheme is about ldB; for 16QAM, The performance difference is about 0.5dB. Although the conventional scheme after doubling the pilot doubling is superior to the virtual pilot scheme in the performance of the block error rate, the conventional scheme after the pilot doubling is added. The frequency overhead causes a waste of system time-frequency resources. In the virtual pilot scheme, the virtual pilot channel is still used for data transmission of the user terminal, so the overhead of the pilot is not increased, and the waste of the system time-frequency resource is avoided.

The second embodiment of the present invention also relates to a channel estimation method, which is substantially the same as the first embodiment, except that in the first embodiment, the power used by the virtual pilot channel is one level; In the embodiment of the present invention, the power used by the virtual pilot channel may be divided into multiple levels according to the location of the user terminal, and the power level is broadcasted to all user terminals by signaling. Since the power used by the virtual pilot channel is divided according to the location of the user terminal, the user terminals at different locations can use the power of different virtual pilot channels, thereby making the embodiment of the present invention more flexible.

A third embodiment of the present invention relates to a channel estimation apparatus, as shown in FIG. 9, including: a demodulation unit 91 for demodulating data of a virtual pilot channel; and a decoding unit 92 for demodulating a unit 91, the demodulated data is decoded; the checking unit 93 is configured to check the decoding result of the decoding unit 92; the determining unit 94 is configured to determine whether the decoding result passes the verification of the checking unit 93; the estimating unit 95, When the judging unit 94 judges the check by the check unit 93, the decoding result is used as a virtual pilot symbol, and the channel estimation is performed using the virtual pilot symbol and the actual pilot symbol.

Since the actual pilot symbols are used, not only the actual pilot symbols but also the verified virtual pilot symbols are used, thereby improving the channel estimation performance of the OFDM system, thereby significantly improving the throughput of the system and reducing the cell's throughput. QAM high-order modulation user's working threshold.

The virtual pilot channel is composed of a set of reserved subcarriers for transmitting data, and the reserved subcarriers for transmitting data are arranged at equal intervals with each subcarrier for transmitting pilot symbols. That is to say, designing the virtual pilot channel to be complementary to the actual pilot channel is equivalent to increasing the pilot density, thereby ensuring the improvement of the channel estimation performance, and since the virtual pilot channel is still used for data transmission of the user terminal, Therefore, the embodiment does not increase the overhead of the pilot, and avoids waste of the system time-frequency resources.

The coded modulation mode used by the virtual pilot channel is a coded modulation mode with low complexity; and/or the power used by the virtual pilot channel is greater than or equal to that used by the pilot channel. Power. The channel estimation apparatus may further include: the obtaining unit 96, Acquiring information about the virtual pilot channel from the broadcast information; the receiving unit 97 is configured to receive data of the virtual pilot channel according to the information about the virtual pilot channel acquired by the acquiring unit 86; The demodulation unit 91 and the decoding unit 92 perform demodulation and decoding according to the information about the virtual pilot channel acquired by the acquisition unit 96.

The estimating unit 95 in the channel estimating apparatus is further configured to perform channel estimation using the actual pilot symbols when the determining unit 94 determines that the check of the checking unit 93 has not passed.

In addition, it is worth mentioning that each unit in the embodiment of the present invention is a logical unit, and in practical applications, there may be various physical implementation manners.

In summary, in the embodiment of the present invention, the data of the virtual pilot channel is demodulated and decoded, and the decoding result is verified. If the verification is performed, the decoding result is used as a virtual pilot symbol, and the virtual pilot is used. The symbol and the actual pilot symbols are used for channel estimation. Since the channel pilot estimation is performed, not only the actual pilot symbols but also the verified virtual pilot symbols are used, thereby improving the channel estimation performance of the OFDM system, thereby significantly improving the throughput of the system and reducing the cell's throughput. QAM high-order modulation user's working threshold.

The virtual pilot channel is allocated to a user terminal with a large signal attenuation, such as a user terminal at the cell edge, so that the user terminal located at the cell center can utilize the virtual pilot for channel estimation. Since the user terminals located in the center of the cell are basically user terminals having a higher working signal-to-noise ratio, the virtual pilot can be made by using the virtual pilot to obtain a more accurate channel estimation by the user terminal located at the center of the cell. The effective utilization of the channel is fully reflected, which can greatly improve the system performance.

Each subcarrier constituting the virtual pilot channel is arranged at equal intervals with each subcarrier for transmitting pilot symbols, that is, the virtual pilot channel is designed to be complementary to the actual pilot channel, which is equivalent to an improvement. Pilot density, thus ensuring the improvement of channel estimation performance Good.

The coded modulation mode used by the virtual pilot channel is a low-complexity code modulation mode, which ensures that the complexity of the system is not increased much while improving the channel estimation performance.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware or by software plus a necessary general hardware platform. Based on such understanding, the technical solution of the present invention can be embodied in the form of a software product that can be stored in a non-volatile storage medium.

(may be a CD-ROM, a USB flash drive, a removable hard drive, etc.), including a number of instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention.

In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

A channel estimation method, comprising the steps of:

Demodulating and decoding data of the virtual pilot channel;

Verify the decoding result;

The channel estimation method according to claim 1, wherein before the step of demodulating and decoding the data of the virtual pilot channel, the method further includes the step of: assigning the virtual pilot channel to at least A user terminal, and the user terminal with a large signal attenuation preferentially allocates the virtual pilot channel.

The channel estimation method according to claim 1, wherein the virtual pilot symbols are reconstructed by a decoding result, a transmission power, and modulation and coding mode information.

The channel estimation method according to claim 1, wherein the virtual pilot channel is composed of a set of reserved subcarriers for transmitting data;

Each of the reserved subcarriers for transmitting data complements each subcarrier used for transmitting pilot symbols.

The channel estimation method according to claim 4, wherein each of the reserved subcarriers for transmitting data is arranged at equal intervals with each subcarrier for transmitting pilot symbols.

The channel estimation method according to claim 1, wherein before the step of demodulating and decoding the data of the virtual pilot channel, the method further comprises the steps of: acquiring the virtual pilot from the broadcast information. Information about the channel;

Receiving data of the virtual pilot channel according to the obtained related information of the virtual pilot channel;

In the step of demodulating and decoding the data of the virtual pilot channel, the demodulation and decoding are performed according to the acquired related information of the virtual pilot channel.

The channel estimation method according to claim 6, wherein the related information of the virtual pilot channel comprises one of the following or any combination thereof: The number and location of subcarriers constituting the virtual pilot channel, the power used by the virtual pilot channel, and the coding modulation scheme used by the virtual pilot channel.

The channel estimation method according to any one of claims 1 to 7, wherein the virtual pilot channel uses a coding modulation scheme having a low complexity.

The channel estimation method according to any one of claims 1 to 7, wherein the virtual pilot channel uses a power greater than or equal to a power used by the pilot channel.

The channel estimation method according to any one of claims 1 to 7, further comprising the steps of:

If the check fails, the actual pilot symbols are used for channel estimation.

A channel estimation apparatus, comprising:

a demodulation unit, configured to demodulate data of the virtual pilot channel;

a decoding unit, configured to decode data demodulated by the demodulation unit, a verification unit, configured to perform verification on a decoding result of the decoding unit, and a determining unit, configured to determine whether the decoding result is passed At the time of verification of the check unit, the decoding result is reconstructed as a virtual pilot symbol, and the channel estimation is performed using the virtual pilot symbol and the actual pilot symbol.

12. The channel estimation apparatus according to claim 11, wherein the virtual pilot channel is composed of a set of reserved subcarriers for transmitting data;

Each of the reserved subcarriers for transmitting data is complemented by subcarriers for transmitting pilot symbols, and may be alternately arranged at equal intervals.

13. The channel estimation apparatus according to claim 11, further comprising:

And an acquiring unit, configured to acquire, from the broadcast information, related information of the virtual pilot channel;

a receiving unit, configured to receive data of the virtual pilot channel according to the related information of the virtual pilot channel acquired by the acquiring unit; The demodulation and decoding unit performs the demodulation and decoding according to the information about the virtual pilot channel acquired by the acquiring unit.

The channel estimation apparatus according to any one of claims 11 to 13, wherein the virtual pilot channel uses a coding modulation scheme with low complexity; and/or the virtual pilot channel is used. The power is greater than or equal to the power used by the pilot channel.

A channel estimation system, comprising:

a first receiving device, configured to receive user data and pilot data;

The channel estimation system according to claim 15, wherein the second receiving device comprises:

a decoding unit, configured to decode data demodulated by the demodulation unit, a verification unit, configured to perform verification on a decoding result of the decoding unit, and a determining unit, configured to determine whether the decoding result is passed Verification of the check unit.

17. The channel estimation system according to claim 15, wherein the virtual pilot channel is composed of a set of reserved subcarriers for transmitting data;

Each of the reserved subcarriers for transmitting data complements each subcarrier used for transmitting pilot symbols, and may be alternately arranged at equal intervals

18. The channel estimation system according to claim 15, further comprising:

The channel estimation system according to any one of claims 15 to 18, wherein the coded modulation mode used by the virtual pilot channel is a low complexity coding modulation mode; and/or,

The virtual pilot channel uses a power greater than or equal to the power used by the pilot channel.

20. A signal transmitting method, characterized in that

Transmitting data in the virtual pilot channel.

The signal transmitting method according to claim 20, wherein each of the reserved subcarriers for transmitting data complements each subcarrier for transmitting pilot symbols.

The signal transmitting method according to claim 21, wherein each of the reserved subcarriers for transmitting data is arranged at equal intervals with each subcarrier for transmitting pilot symbols.

The signal transmitting method according to claim 20, wherein the virtual pilot channel uses a coded modulation method having a low complexity.

The signal transmitting method according to claim 20, wherein the virtual pilot channel uses a power greater than or equal to a power used by the pilot channel.

The signal transmitting method according to claim 20, wherein the method further comprises: broadcasting related information of the virtual pilot channel to all user terminals by signaling.

26. A signal transmitting device, characterized in that

a channel forming unit, configured to form a set of reserved subcarriers for transmitting data into a virtual pilot channel;

a channel allocation unit, the virtual pilot channel is allocated to at least one user terminal, and the user terminal with a large signal attenuation preferentially allocates the virtual pilot channel; And a sending unit, configured to send data in the virtual pilot channel.

The signal transmitting apparatus according to claim 26, wherein each of the reserved subcarriers for transmitting data complements each subcarrier for transmitting pilot symbols.

The signal transmitting apparatus according to claim 27, wherein each of the reserved subcarriers for transmitting data is arranged at equal intervals with each subcarrier for transmitting pilot symbols.

The signal transmitting apparatus according to claim 26, wherein the virtual pilot channel uses a coded modulation method having a low complexity.

The signal transmitting apparatus according to claim 26, wherein the virtual pilot channel uses a power greater than or equal to a power used by the pilot channel.

The signal transmitting apparatus according to claim 26, wherein the apparatus further comprises: a broadcasting unit that broadcasts related information of the virtual pilot channel to all user terminals by signaling.