CN101741797B - Method and device for transmitting multi-antenna broadcast - Google Patents

Abstract

An embodiment of the present invention provides a method for transmitting multi-antenna broadcasting, including: performing channel coding on at least two service data streams respectively; multiplexing the channel-coded service data streams into one service data stream through hierarchical modulation; The multiplexed service data streams are subjected to transmit diversity processing to obtain multiple channels of data corresponding to the number of transmit antennas; and the multiple channels of data are sent to corresponding transmit antennas. The embodiment of the present invention also provides a multi-antenna broadcast sending device. The embodiment of the present invention introduces multi-antenna technology to the broadcast channel, adopts transmit diversity to improve the signal-to-noise ratio of the receiver, and combines hierarchical modulation with MIMO to improve channel capacity and spectrum efficiency.

Description

Transmission method and device for multi-antenna broadcasting

technical field

The present invention relates to the communication field, in particular to a multi-antenna broadcast sending method and device.

Background technique

Multi-Input Multi-Output (MIMO) technology is an important technology for third-generation and future mobile communication systems to achieve high data rates, large system capacity, and improve transmission quality. This technology can double the capacity and spectrum utilization of the communication system without increasing the bandwidth.

The core of the MIMO system is to use multiple antennas to suppress channel fading. Typically, multipath causes fading and is therefore considered a detrimental factor. But for MIMO systems, multipath can be exploited as an advantage. Figure 1 shows a schematic diagram of a MIMO system. The transmission information stream s(k) undergoes space-time coding to form N information sub-streams _ci (k), i=1,...,N. The N substreams are transmitted by N antennas, and received by M receiving antennas after passing through the spatial channel. Multi-antenna receivers are able to separate and decode these data sub-streams using space-time coding processing for optimal processing. The transmitted N substreams are sent to the channel at the same time and occupy the same frequency band, so the bandwidth is not increased. If the channel responses between the transmit and receive antennas are independent, a MIMO system can create multiple parallel spatial channels. If information is transmitted independently through these parallel spatial channels, the data rate can be increased; if the same information is transmitted through these parallel spatial channels, space diversity gain can be obtained and performance can be improved. At present, commonly used ways to obtain space diversity include space-time block code (Spatial Time Block Code, STBC), space-frequency block code (Spatial Frequency Block Code, SFBC) and other ways.

Broadcast channels are characterized as downlinks for point-to-multipoint transmissions. A typical scenario is that there is one base station and multiple mobile terminals in a cell, and the base station sends broadcast signals to multiple mobile terminals at the same time. When the base station sends broadcast signals, it does not know the information of the mobile terminals, such as the number of mobile terminals, the channel status of the mobile terminals, and so on. At present, broadcast channels only consider single-antenna transmission. With the development of communication technology, especially the introduction of MIMO technology, considering multi-antenna transmission in broadcast channels to improve performance and spectrum efficiency has become a research hotspot.

Hierarchy Modulation (HM) is an enhanced modulation technology that has been adopted by Ultra Mobile Broadband (UMB), Digital Video Broadcasting (DVB), MediaFLO (a mobile TV standard proposed by Qualcomm), etc. Standard adoption. Hierarchical modulation can obtain the largest broadcast channel capacity in a single-antenna scenario, or it is one of the best ways to obtain broadcast channel capacity.

A typical implementation block diagram of HM is shown in Figure 2:

For two different service streams (service stream 1 and service stream 2), after channel coding, the data of the two different service streams are multiplexed through hierarchical modulation. The multiplexing method can assign two high-reliability bits of 16QAM (Quadrature Amplitude Modulation, quadrature amplitude modulation) to service flow 1, and two low-reliability bits to service flow 2; or, two different service flows After performing quadrature phase shift keying (Quadrature Phase Shift Keying, QPSK) modulation, different power and phase controls are superimposed together to complete the multiplexing of different service data streams.

However, the inventors found that multi-antenna technology is not introduced in the current broadcast channel, resulting in low performance and spectral efficiency; hierarchical modulation and MIMO are not combined, so that hierarchical modulation can only meet the maximum broadcast channel capacity in a single-antenna scenario .

Contents of the invention

In view of this, embodiments of the present invention provide a method and device for transmitting multi-antenna broadcasting, which combines hierarchical modulation with MIMO to improve channel capacity and spectrum efficiency.

An embodiment of the present invention provides a multi-antenna broadcast sending method, including:

performing channel coding on at least two service data streams;

multiplexing the channel-coded service data stream into one service data stream through hierarchical modulation;

Perform transmit diversity processing on the multiplexed service data streams to obtain multi-channel data corresponding to the number of transmit antennas;

and sending the multiple channels of data to corresponding transmitting antennas.

The embodiment of the present invention also provides a multi-antenna broadcast sending device, including:

A channel coding module, configured to perform channel coding on at least two service data streams respectively;

A hierarchical modulation module, configured to multiplex the channel-coded service data stream into one service data stream;

A transmit diversity module, configured to perform transmit diversity processing on the multiplexed service data streams to obtain multi-channel data corresponding to the number of transmit antennas;

At least two transmitting antennas are used to send the multi-channel data to the receiving end.

The embodiment of the present invention introduces multi-antenna technology to the broadcast channel, adopts transmit diversity to improve the signal-to-noise ratio of the receiver, and combines hierarchical modulation with MIMO to improve channel capacity and spectrum efficiency.

Description of drawings

FIG. 1 is a basic block diagram of a prior art MIMO system;

FIG. 2 is a schematic diagram of hierarchical modulation in the prior art;

FIG. 3 is a schematic flowchart of a multi-antenna broadcast sending method according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a 16QAM rule constellation and its mapping method in Embodiment 1 of the present invention;

FIG. 5 is a schematic diagram of a constellation diagram formed by superposition of two layers of QPSK and its mapping method in Embodiment 1 of the present invention;

FIG. 6 is a schematic diagram of processing by the Alamouti method for two transmitting antennas in Embodiment 1 of the present invention;

FIG. 7 is a schematic diagram of delayed transmit diversity in Embodiment 1 of the present invention;

FIG. 8 is a schematic diagram of angle deflection transmit diversity in Embodiment 1 of the present invention;

FIG. 9 is a schematic flowchart of a method for transmitting multi-antenna broadcasting according to Embodiment 2 of the present invention;

FIG. 10 is a schematic flowchart of a method for transmitting multi-antenna broadcasting according to Embodiment 3 of the present invention;

FIG. 11 is a schematic structural diagram of a transmitting device for multi-antenna broadcasting according to Embodiment 4 of the present invention;

FIG. 12 is a schematic diagram of an improved structure of a multi-antenna broadcast sending device in Embodiment 4 of the present invention;

Fig. 13 is a schematic structural diagram of a further improvement of the multi-antenna broadcast sending device in Embodiment 4 of the present invention.

Detailed ways

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Embodiment one of the present invention:

Please refer to FIG. 3 , a method for transmitting multi-antenna broadcasting according to an embodiment of the present invention, including:

Step 31, perform channel coding on at least two service data streams respectively.

In this embodiment, N (N≥2) service data streams are involved, and channel coding includes, but is not limited to: Turbo code, LDPC code (low-density parity-check code), or convolutional code. The channel coding methods selected for different service data streams may be the same or different.

Step 32, multiplexing the coded service data streams into one data stream through hierarchical modulation.

In this embodiment, the way of hierarchical modulation includes but is not limited to: (1) assigning regular or irregular QAM bits with different reliability to different service flows; or (2) using basic modulation for service flows of different layers Ways, such as QPSK, are superimposed by different powers or angles.

For method (1), take regular QAM as an example. Regular QAM is a high-order modulation method currently used. Figure 4 shows the regular 16QAM modulation method (referring to the QAM modulation method containing 16 symbols) used in UMB. The constellation The shape of the distribution is square, with equal distances between adjacent rows and adjacent columns.

For method (2), the service flows of different layers are modulated by QPSK, and the constellation diagram (from UMB) is obtained by superimposing different powers or angles. As shown in Figure 5, α is the amplitude of the first service flow, and β is the amplitude of the second service flow. The magnitude of the two-layer service flow, θ is the angle between the two-layer service flow.

Step 33: Perform transmit diversity processing on the multiplexed service data streams to obtain multiple channels of data corresponding to the number of transmit antennas.

In this embodiment, transmit diversity includes, but is not limited to: space-time block code STBC or space-frequency block code SFBC, delayed transmit diversity, angle deflection transmit diversity, time-switched transmit diversity or frequency switched transmit diversity, or between different transmit diversity combine etc. Introduce respectively below.

1. Space-time block code STBC or space-frequency block code SFBC

The basic principles of space-time block codes and space-frequency block codes are the same. Space-time block codes place signals in two dimensions of space and time, while space-frequency block codes place signals in two dimensions of space and frequency domains. The methods are the same.

]，对于天线2，输出的符号为[s₂，

]，如果输出的符号在不同的时间维度上就是空时块码，如果在不同的频率上就是空频块码。For example, for the diversity mode of two transmit antennas, the processing method of the Alamouti method (specifically referring to the space-time block code or space-frequency block code of two transmit antennas) is shown in Figure 6, and the input symbols are s ₁ , s ₂ , For antenna 1, the sign of the output is [s ₁ , -

], for antenna 2, the output symbol is [s ₂ ,

], if the output symbols are space-time block codes in different time dimensions, they are space-frequency block codes in different frequencies.

In this embodiment, space and time coding is used to realize space diversity and time diversity for the multiplexed service data stream, and space and frequency coding is used to realize space diversity and frequency diversity, thereby reducing the channel bit error rate. In the secondary transmit antenna scenario, higher diversity gain can be obtained.

2. Delayed launch diversity

Delayed transmit diversity is shown in Figure 7, which divides multiplexed service data streams into copies with different delays and transmits them on different antennas. For example, for antenna 1, send at time t1; for antenna 2, delay Δt, and send at t1+Δt; for antenna k, delay (k-1)*Δt, and send at t1+(k-1)*Δt .

3. Angle deflection transmit diversity

Angle deflection transmit diversity is shown in Figure 8, which is to diversify the multiplexed service data streams into copies of different angles and send them on different antennas. For example, for antenna 2, the transmission is deflected by an angle of θ from the angle of antenna 1; for antenna k, the transmission is deflected by an angle of θ _k-1 .

4. Select transmit diversity

Selective transmit diversity usually includes time-switched transmit diversity and frequency-switched transmit diversity. When the sender does not know the channel information, the sender can randomly select antennas for transmission. Random selection of transmission in time is time-switched transmit diversity. Selecting in frequency This is frequency switching transmit diversity.

5. Combination of different transmit diversity

According to the foregoing descriptions of the four kinds of transmit diversity, the combination of space-time block code and time-switched transmit diversity is briefly introduced below as an example. Those skilled in the art understand and can freely choose any other combination of transmit diversity.

Randomly select antennas to transmit at different times (time-switching transmit diversity), for example, select antenna 1 to transmit at time t1, and select antenna 2 to transmit at time t2; and when transmitting from antenna 1 at time t1, the space-time block code is used again, using Coding in space and time realizes space diversity and time diversity; when transmitting by antenna 2 at time t2, space-time block codes are also used to realize space diversity and time diversity by using space and time coding.

Step 34, sending the multiple channels of data to corresponding transmitting antennas.

The multi-channel data corresponding to the number of transmit antennas obtained through transmit diversity processing will be sent to the corresponding transmit antennas to be sent to the receiver. It should be understood that the method for sending multi-antenna broadcast in this embodiment is not only applicable to the case where the receiving party (such as a mobile terminal) has two or more receiving antennas, but also applicable to the case where the receiving party has only one receiving antenna.

The embodiment of the present invention introduces multi-antenna technology to the broadcast channel, adopts transmit diversity to improve the signal-to-noise ratio of the receiver, and combines hierarchical modulation with MIMO to improve channel capacity and spectrum efficiency.

Embodiment two of the present invention:

Please refer to FIG. 9 , the transmission method of multi-antenna broadcasting in Embodiment 2 of the present invention combines OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) with MIMO. The difference from Embodiment 1 is that in this embodiment After the multiplexed service data streams are processed by transmit diversity to obtain data corresponding to at least two transmit antennas, they are not directly sent to the transmit antennas, but are first modulated by OFDM and then sent to the transmit antennas.

Step 91, respectively perform channel coding on at least two service data streams.

Step 92, multiplexing the channel-coded service data streams into one service data stream through hierarchical modulation.

Step 93: Perform transmit diversity processing on the multiplexed service data streams to obtain multiple channels of data corresponding to the number of transmit antennas.

Steps 91-93 are the same as steps 31-33 in Embodiment 1, and will not be repeated here.

Step 94, performing OFDM modulation on the multiple channels of data respectively.

OFDM modulation can divide the channel into several orthogonal sub-channels, convert high-speed data signals into parallel low-speed sub-data streams, and modulate them for transmission on each sub-channel. The bandwidth of each sub-channel is very narrow, so the fading on each sub-channel can be regarded as flat fading, so that inter-symbol interference can be suppressed, and it can be well combined with multiple antennas.

Step 95, sending the OFDM-modulated multi-channel data to corresponding transmitting antennas. This step is basically the same as step 34 of Embodiment 1. In step 34, the multi-channel data sent to the transmitting antenna is the data obtained through transmit diversity processing without OFDM modulation; the multi-channel data sent to the transmitting antenna in this step It is the data processed by transmit diversity and modulated by OFDM.

As a further improvement of this embodiment, after performing channel coding on at least two service data streams in step 91, further steps are included:

Perform interleaving processing on the channel-coded service data streams respectively.

The interleaving process is to obtain time diversity without adding any overhead by disturbing the code word order of the service data stream after channel coding, which is related to the bit decorrelation and randomization, so as to facilitate multiplexing during hierarchical modulation. The interleaving of the streams may or may not be the same.

After the interleaving process, step 92 is performed to multiplex the service data stream into one data stream through hierarchical modulation.

In this embodiment, OFDM is combined with MIMO, which can not only improve diversity gain and channel capacity, but also use OFDM to convert frequency selective fading into flat fading on sub-carriers, which can eliminate inter-symbol interference.

Embodiment three of the present invention:

Please refer to FIG. 10 , the difference between the transmission method of multi-antenna broadcasting in Embodiment 3 of the present invention and Embodiment 2 is that in this embodiment, the multiplexed service data streams are obtained through transmit diversity processing and at least two transmit antennas After the corresponding data is inserted into the pilot and carrier mapping, OFDM modulation is performed before being sent to the transmitting antenna.

Step 101, perform channel coding on at least two service data streams respectively.

Step 102, multiplexing the channel-coded service data stream into one service data stream through hierarchical modulation.

Step 103: Perform transmit diversity processing on the multiplexed service data streams to obtain multiple channels of data corresponding to the number of transmit antennas.

Steps 101-103 are the same as steps 91-93 in the second embodiment, and will not be repeated here.

Step 104, respectively inserting pilot frequency and carrier mapping into the multiple channels of data.

Carrier mapping is to map each channel of data into OFDM symbols respectively. Inserting pilots is to insert known information—pilots into the time-frequency resource blocks composed of OFDM symbols. The fading situation of the entire channel time-frequency resource block to the receiving end. The pilot carrier does not transmit any useful signal code stream, and can resist various interferences. The channel estimation is convenient for the receiving end to obtain the estimated results, and can understand the frequency and phase distortion of each carrier, and then the receiving end can analyze the signal based on this information The amplitude and phase are corrected, that is, channel equalization.

Step 105 is basically the same as step 94 in the second embodiment, that is, perform OFDM modulation on the multi-channel data after the insertion of the pilot and carrier mapping.

Step 106 is basically the same as step 95 in the second embodiment, that is, the multi-channel data modulated by OFDM is sent to corresponding transmitting antennas.

Similarly, as a further improvement of this embodiment, after performing channel coding on at least two service data streams in step 101, further steps are included:

Perform interleaving processing on the coded service data streams respectively.

The interleaving process is to obtain time diversity without adding any overhead by disturbing the code word order of the service data stream after channel coding, which is related to the bit decorrelation and randomization, so as to facilitate multiplexing during hierarchical modulation. The interleaving of the streams may or may not be the same.

In this embodiment, OFDM is combined with MIMO, which can not only improve diversity gain and channel capacity, but also use OFDM to convert frequency selective fading into flat fading on sub-carriers, which can eliminate inter-symbol interference. At the same time, before OFDM modulation, the multi-channel data is also inserted into the pilot and carrier mapping processing, which is more conducive to channel equalization at the receiving end.

Embodiment four of the present invention:

Please refer to FIG. 11 , the transmission device for multi-antenna broadcasting in Embodiment 4 of the present invention includes:

The channel coding module 11 is configured to perform channel coding on at least two service data streams respectively.

In this embodiment, k (k≥2) service data streams are involved, and channel coding includes, but is not limited to: Turbo code, LDPC code (low density parity check code), or convolutional code. For different service data streams, the channel coding modes selected by the channel coding module 11 may be the same or different.

The hierarchical modulation module 12 is configured to multiplex the channel-coded service data streams into one service data stream.

In this embodiment, the way the hierarchical modulation module performs hierarchical modulation includes but is not limited to: (1) assigning bits of different reliability of regular or irregular QAM to different service flows; or (2) assigning service flows of different layers Using basic modulation methods, such as QPSK, through different power or angle superposition.

The transmit diversity module 13 is configured to perform transmit diversity processing on the multiplexed service data streams to obtain multiple channels of data corresponding to the number of transmit antennas.

In this embodiment, the transmit diversity module 13 may specifically include:

The space-time block code module is used to implement space diversity and time diversity by encoding the multiplexed service data streams in space and time; or

A space-frequency block code module, which is used to realize space diversity and frequency diversity by using space and frequency coding for multiplexed service data streams; or

Delayed transmit diversity module, used to divide the multiplexed service data streams into copies with different delays, so as to be sent on different transmit antennas; or

An angle deflection transmit diversity module, used to diversify the multiplexed service data streams into copies of different angles for transmission on different transmit antennas; or

A time-switched transmit diversity module for randomly selecting transmit antennas in time for transmission; or

The frequency switching transmit diversity module is used for randomly selecting transmit antennas on frequencies for transmission.

In an actual application scenario, the transmit diversity module 13 may specifically be any of the foregoing diversity modules or a combination of any diversity modules.

At least two transmitting antennas 14 are used to send the multiple channels of data to the receiving end.

In this embodiment, the number of transmitting antennas is N (N≥2), and the transmission through multiple antennas can effectively suppress channel fading.

Referring to Figure 12 again, as a further improvement to this embodiment, the multi-antenna broadcast sending device also includes:

The orthogonal frequency division multiplexing OFDM modulation module 15 is arranged between the transmit diversity module 12 and the transmit antenna 14, and is used to perform OFDM modulation on the multi-channel data obtained by the diversity processing of the transmit diversity module 12 respectively.

OFDM modulation can divide the channel into several orthogonal sub-channels, convert high-speed data signals into parallel low-speed sub-data streams, and modulate them for transmission on each sub-channel. The bandwidth of each sub-channel is very narrow, so the fading on each sub-channel can be regarded as flat fading, so that inter-symbol interference can be suppressed, and it can be well combined with multiple antennas.

Please also refer to Figure 13, as a further improvement to this embodiment, the multi-antenna broadcast sending device further includes:

Insert pilot frequency and carrier mapping module 17, be arranged between described transmission diversity module 12 and OFDM modulation module 15, be used for mapping the multi-channel data that described transmission diversity module 12 diversity processing obtains to OFDM symbol respectively, in OFDM symbol Pilots are inserted into the formed time-frequency resource blocks, and the fading conditions of the entire channel time-frequency resource blocks between the transmitting end and the receiving end are estimated according to the fading conditions at the locations of the pilot frequencies. In order to facilitate the receiving end to perform channel equalization according to the channel estimation situation.

For the multi-antenna broadcast sending device shown in Figures 11-13, an interleaving module 16 can also be set between the channel coding module 11 and the hierarchical modulation module 12 to encode the service data stream encoded by the channel coding module 11 The interleaving process is performed respectively, which specifically de-correlates bits related to the order of code words of the service data stream after disturbing the channel coding, so as to obtain time diversity and facilitate the multiplexing of the hierarchical modulation module 12 . For different business data streams, the interleaving module 16 can perform the same or different interleaving methods.

The embodiment of the present invention introduces multi-antenna technology to the broadcast channel, adopts transmit diversity to improve the signal-to-noise ratio of the receiver, and combines hierarchical modulation with MIMO to improve channel capacity and spectrum efficiency.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. A sending method for multi-antenna broadcasting, characterized in that: comprising: performing channel coding on at least two service data streams; multiplexing the channel-coded service data stream into one service data stream through hierarchical modulation; Perform transmit diversity processing on the multiplexed service data streams to obtain multi-channel data corresponding to the number of transmit antennas; sending the multi-channel data to corresponding transmitting antennas; Wherein, the manner of the hierarchical modulation is specifically one of the following manners: Assign regular or irregular quadrature amplitude modulation QAM bits of different reliability to different service flows; or The service flow of different layers adopts the basic modulation mode, and is superimposed through different power or angle. 2. The method according to claim 1, characterized in that: the transmission diversity method is specifically one of the following methods or any combination: Realize space diversity and time diversity by using space and time coding for multiplexed service data streams; or Realize space diversity and frequency diversity by using space and frequency coding for multiplexed service data streams; or Diversify multiplexed service data streams into copies with different delays; or Diversify multiplexed business data streams into copies from different angles; or According to the feedback of the receiving end on the channel quality of the transmitting antenna, the transmitting antenna is randomly selected for transmission. 3. The method according to claim 1, characterized in that: after the multiplexed service data streams are subjected to transmit diversity processing, and after obtaining multi-channel data corresponding to the number of transmit antennas, further comprising: performing OFDM modulation on the multiple channels of data respectively. 4. The method according to claim 3, characterized in that: after the multiplexed service data streams are subjected to transmit diversity processing to obtain multiple data corresponding to the number of transmitting antennas, the multiple data are respectively processed Before OFDM modulation, it also includes: Inserting pilot frequency and carrier mapping into the multiple channels of data. 5. The method according to claim 3 or 4, characterized in that: after performing channel coding on at least two service data streams respectively, further comprising: Perform interleaving processing on the channel-coded service data streams respectively. 6. A transmitting device for multi-antenna broadcasting, characterized in that: comprising: A channel coding module, configured to perform channel coding on at least two service data streams respectively; A hierarchical modulation module, configured to multiplex the channel-coded service data stream into one service data stream; A transmit diversity module, configured to perform transmit diversity processing on the multiplexed service data streams to obtain multi-channel data corresponding to the number of transmit antennas; At least two transmitting antennas are used to send the multi-channel data to the receiving end; Wherein, the manner of performing hierarchical modulation by the hierarchical modulation module includes: Assign regular or irregular quadrature amplitude modulation QAM bits of different reliability to different service flows; or The service flow of different layers adopts the basic modulation mode, and is superimposed through different power or angle. 7. The device according to claim 6, characterized in that: the transmit diversity module specifically may be: The space-time block code module is used to implement space diversity and time diversity by encoding the multiplexed service data streams in space and time; or A space-frequency block code module, which is used to realize space diversity and frequency diversity by using space and frequency coding for multiplexed service data streams; or Delayed transmit diversity module, used to divide the multiplexed service data streams into copies with different delays, so as to be sent on different transmit antennas; or An angle deflection transmit diversity module, used to diversify the multiplexed service data streams into copies of different angles for transmission on different transmit antennas; or A time-switched transmit diversity module for randomly selecting transmit antennas in time for transmission; or The frequency switching transmit diversity module is used for randomly selecting transmit antennas on frequencies for transmission. 8. The device according to claim 6, further comprising: The orthogonal frequency division multiplexing OFDM modulation module is used to perform OFDM modulation on the multi-channel data obtained by the diversity processing of the transmit diversity module. 9. The device according to claim 8, further comprising: Insert a pilot and carrier mapping module, which is set between the transmit diversity module and the OFDM modulation module, and is used to map the multi-channel data obtained by the diversity processing of the transmit diversity module into OFDM symbols respectively, in Insert pilots in the time-frequency resource blocks formed by OFDM symbols, so that the OFDM modulation module performs OFDM modulation on the multi-channel data after inserting pilots and carrier mapping, according to the fading situation at the position of the pilots Estimate the fading of the entire channel time-frequency resource block from the transmitter to the receiver. 10. The device according to claim 8 or 9, further comprising: The interleaving module is arranged between the channel coding module and the hierarchical modulation module, and is used for interleaving the service data streams coded by the channel coding module, so as to facilitate the multiplexing of the hierarchical modulation module.

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