CN104639493A - Signal transmission method - Google Patents

Abstract

The present application discloses a signal transmission method, which includes: grouping data symbols to be transmitted, each group including L data symbols; wherein, L is the preset number of data symbols sent for each superimposition; for any group Data symbols, performing serial-to-parallel conversion on the L data symbols in the group and performing pulse shaping respectively, and performing different delays on the formed time-domain waveforms, and then superimposing the delayed time-domain waveforms before sending; Wherein, the delays of K time-domain waveforms in any group of data symbols are less than T; K is the preset number of data symbols to be overlapped and sent, L is greater than or equal to K, and T is the time length of each data symbol. By applying the present application, the transmission rate and spectrum efficiency of the data transmission sequence can be improved, and intersymbol interference can be effectively controlled.

Description

A method of signal transmission

technical field

The present application relates to communication technology, in particular to a signal transmission method.

Background technique

In the future, mobile communication will have very high requirements for data transmission rate, but the frequency resources available for mobile communication are very limited. How to meet the demand for explosive growth of communication traffic under the condition of extremely limited frequency resources, only by maximizing the frequency spectrum Efficiency is the only way to meet these needs. However, judging from the current technical means and even theoretical concepts, this is quite difficult.

With the existing theories and technologies, we can only increase the transmission rate by expanding the bandwidth. In the case of limited spectrum resources, we are not allowed to expand the bandwidth all the time, which forces us to find some new transmission technologies with high spectral efficiency.

As we all know, the International Telecommunication Union (International Telecommunication Union, ITU) has determined two standards for the terrestrial wireless interface of IMT-Advanced (International Mobile Telecommunications-Advanced), namely LTE-Advanced (Long Term Evolution-Advanced) and WirelessMAN-Advanced ( Wireless Metropolitan Area Network-Advanced), both of these two standards use OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) as the downlink transmission technology. At the same time, WirelessMAN-Advanced also chooses OFDM as its uplink transmission technology. OFDM is a multi-carrier transmission technology in which subcarriers overlap each other in the frequency domain but maintain orthogonality. Its basic features are as follows:

1) Relatively many narrowband subcarriers are used, while direct multicarrier extension only occupies a few subcarriers;

2) In the time domain, a simple rectangular pulse is used for shaping and sent in an orthogonal form;

In the frequency domain, the sub-carriers are closely arranged and overlapping and orthogonal, and the interval is △f=1/T, where T is the modulation symbol period of the sub-carriers.

Figure 1 and Figure 2 are the OFDM frequency domain single subcarrier and the frequency domain multi-subcarrier orthogonal superposition respectively. It can be seen from the figure that the OFDM frequency domain is orthogonal superposition. Figure 3 is a schematic diagram of OFDM time domain orthogonality, in which each box represents only one time domain data symbol and has no special meaning. We can also see from the figure that OFDM time domain is also orthogonal.

As an improvement of OFDM, SC-FDMA (Single-Carrier Frequency Division Multiple Access) is also orthogonal in the time domain and frequency domain, and it is used in the LTE/LTE-A uplink. Not limited to this, most of the existing technologies are orthogonal in time domain and frequency domain.

To sum up, in the existing technologies, most of the transmitters are time-domain orthogonal, so in the case of scarce frequency resources, the time-domain orthogonal model can no longer meet the requirements of high-speed and high-frequency spectrum in future mobile communications. efficiency requirements.

Even for those non-orthogonal time-domain overlapping techniques at the sending end, the high complexity of its implementation is a major bottleneck. For example, the length of the symbol sequence that needs to be sent at the sending end is long, the interference is uncontrollable, and the long sequence is not conducive to combining with some coding and modulation techniques that are widely used now; for another example, the entire sending sequence needs to be decoded at the receiving end, Judgment, the delay is relatively large, which is not conducive to high-speed data flow processing.

Contents of the invention

The present application provides a signal transmission method, which can improve transmission rate and spectrum efficiency, and effectively control intersymbol interference.

In order to achieve the above object, the application adopts the following technical solutions:

A signal transmission method, comprising:

The data symbols to be transmitted are grouped, and each group includes L data symbols; wherein, L is the preset number of data symbols sent for each superimposition;

For any group of data symbols, perform serial-to-parallel conversion on the L data symbols in the group and perform pulse shaping respectively, and perform different delays on the formed time-domain waveforms, and then superimpose the delayed time-domain waveforms after sending;

Wherein, the delays of the K time-domain waveforms in any group of data symbols are less than T; K is the preset number of overlapping transmitted data symbols, L is greater than or equal to K, and T is the time length of each data symbol.

Preferably, said delaying each of the formed time-domain waveforms respectively includes:

When L>K, for the i-th data symbol in any group of data symbols, the corresponding delay time Wherein, K is the preset overlapping number of the time-domain waveforms;

When L=K, for the i-th data symbol in any group of data symbols, its corresponding delay time

${\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1,2</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span>$

Preferably, the difference between L and K is smaller than a set threshold.

Preferably, the threshold, L and K are determined according to the system's control requirements on inter-symbol interference.

Preferably, the method further includes: receiving the transmitted time-domain waveform, and performing sampling and equalization detection on the received signal to obtain each group of transmitted data symbols.

Preferably, the minimum mean square error method, zero-forcing method or matched filtering method is used for the equalization detection.

It can be seen from the above technical solution that in this application, the data symbols are first grouped, and the data symbols in each group are serial-to-parallel converted and then delayed for different times, and then the delayed signals are superimposed and sent. Through the above method, more signals can be sent within the same time, so that the transmission rate and spectrum efficiency can be improved. At the same time, the controllability of the overlapping number is used to control the intersymbol interference.

Description of drawings

FIG. 1 is a schematic diagram of a single subcarrier in the OFDM frequency domain;

Figure 2 is the orthogonal superposition of multiple subcarriers in the OFDM frequency domain;

FIG. 3 is a schematic diagram of time domain quadrature;

FIG. 4 is a schematic diagram of the basic flow of the signal transmission method in the present application;

Fig. 5 is a schematic diagram of (6,4) high spectral efficiency transmission signal in the present application;

Figure 6 is a schematic diagram of (L, K) transmission signals with high spectral efficiency in this application

Fig. 7 is the transmitter model of L>K in this application;

Fig. 8 is a schematic diagram of K-fold high spectral efficiency transmission signal;

Fig. 9 is the transmitter model of L=K in this application;

Fig. 10 is the receiver model of L>K among the present application;

Fig. 11 is the receiver model of L=K among the present application;

FIG. 12 is a schematic diagram of 4-fold high spectral efficiency transmission signals in this application.

Detailed ways

In order to make the purpose, technical means and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

This application proposes a transmission method with controllable interference and high spectral efficiency. FIG. 4 is a schematic flow chart of a signal transmission method in the present application. As shown in Figure 4, the method includes:

Step 401, group the data symbols to be transmitted.

When grouping, each group includes L data symbols; wherein, L is the preset number of data symbols sent for each superimposition. L is described in more detail in the detailed description below.

For each group of grouped data symbols, the processing of steps 402-403 is performed. In the description of steps 402 and 403 below, only the processing of a group of data symbols (packet A) is taken as an example for description.

Step 402: Perform serial-to-parallel conversion on the data symbols in packet A, and then perform pulse shaping processing on each data symbol through a pulse shaping filter to form a time-domain waveform.

In step 403, different delays are performed on each time domain waveform in the packet A, and then the delayed time domain waveforms are superimposed and sent.

When delay processing is performed, the delays of the K data symbols in the packet A are all less than T. Wherein, T is the time length of each data symbol. Through such delay processing, when the time-domain waveforms are superimposed and sent, some time-domain waveforms in the K data symbols are overlapped, so that spectral efficiency and data transmission rate can be improved. At the same time, further through the value of K, the introduced intersymbol interference can be controlled.

The superimposed signal after the above processing is sent, and then receiving processing is performed through step 404 .

Step 404: Receive the transmitted time-domain waveform, and perform sampling and equalization detection on the received signal to obtain each group of transmitted data symbols.

So far, the basic flow of the signal transmission method in this application ends. Wherein, the processing of steps 401-403 is the processing of the sending end, and step 404 is the processing of the receiving end. The most basic signal transmission method of this application may only include the sending method.

The specific implementation of the signal transmission method in this application will be described in detail below. Firstly, the sending method of the sending end is described in detail.

In order to describe the sender model in detail, two definitions are first introduced:

Definition 1 The number of time-domain waveforms transmitted each time overlapping is called the code length, that is, the aforementioned L.

Definition 2 The overlapping number of time-domain waveforms is called the multiplicity, that is, the aforementioned K.

And, L and K satisfy the relationship: L≥K.

For example, what is shown in Figure 5 is (L,K)=(6,4) high spectral efficiency transmission signal. It should be noted in the figure that each box only represents a time-domain waveform, and has no other special meaning .

If L and K are comparable, it is considered that the interference introduced at this time is controllable. In general, if the specific value of L is not specified, it is considered that L=K. For example, a 4-fold high spectral efficiency transmission signal specifically refers to a (4, 4) high spectral efficiency transmission signal. Of course, the values of L and K can also be set according to actual needs. In order to ensure that L and K are comparable, the difference between L and K can be made smaller than the set threshold. The specific values of the threshold, L and K can be determined according to the system Inter-symbol interference control requirements are set. The following descriptions are made respectively according to different value relationships of L and K.

1. L>K sender model

Consider a (L, K) transmission signal with high spectral efficiency, and the schematic diagram of the transmission signal is shown in Fig. 6 . If the time length of each symbol at the sender is T, then its symbol rate is

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; L</span>}\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Accordingly, we consider a sender model with L>K, as shown in Figure 7. For the sender model shown in Figure 7, its main steps are as follows:

Step 1: Group the data symbols to be transmitted. The method of grouping is to group each L data symbols. Then, for N data symbols, the group number M is

in Indicates rounding up.

Step 2: Perform serial-to-parallel conversion on the L data symbols of the first group, and then perform pulse shaping on them respectively to form time-domain waveforms g _i (t), (i=1,2,...,K,K+1 ,...,L).

Step 3: Delay each time-domain waveform obtained in Step 2 to obtain

x _i (t) = g _i (t-τ _i ), (i=1,2,...,K,K+1,...,L), (3)

Among them, the delay τ _i of the i-th delayer is

Indicates rounding down.

Step 4: Add the delayed x _i (t) according to the method shown in Fig. 6 to obtain the time-domain waveform x(t) to be sent, and then send x(t) out.

Step 5: For groups 2 to M, repeat steps 2 to 4 to complete the transmission of all data symbols to be transmitted.

2. The sender model of L=K

Consider a K-fold transmission signal with high spectral efficiency, and the schematic diagram of the transmitted signal is shown in Fig. 8 . If the time length of each symbol at the sender is T, then its symbol rate is

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; K</span>}\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Accordingly, we consider a transmitter model of L=K, as shown in FIG. 9 . For the sender model shown in Figure 9, its main steps are as follows:

Step 1: Group the data symbols to be transmitted. The method of grouping is to group each K data symbols. Then, for N data symbols, the number of groups M is

in Indicates rounding up.

Step 2: Perform serial-to-parallel conversion on the K data symbols in the first group, and then perform pulse shaping on them respectively to form time-domain waveforms g _i (t), (i=1, 2, . . . , K).

Step 3: Delay each time-domain waveform obtained in Step 2 to obtain

x _i (t) = g _i (t-τ _i ), (i = 1,2,...,K), (7)

Among them, the delay τ _i of the i-th delayer is

${\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1,2</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

Step 4: Add the delayed x _i (t) according to the method shown in Fig. 8 to obtain the time-domain waveform x(t) to be sent, and then send x(t) out.

Step 5: For groups 2 to M, repeat steps 2 to 4 to complete the transmission of all data symbols to be transmitted.

The above is the specific implementation of the sending method in the signal transmission method in this application. The receiving method is described in detail below, and different relationships between L and K are also described separately.

1. Receiver model of L>K

Consider a receiver model with L>K, as shown in Figure 10. For the receiver model shown in Figure 10, the main steps are as follows:

Step 1: Sampling the received signal r(t), then the output of the sampler is

y=Hx+n, (9)

Where y=[y ₁ ,y ₂ ,…,y _L+K-1 ] ^T , y _i represents the sampling value at each sampling moment; x=[x ₁ ,x ₂ ,…,x _K ,x _K+1 , ...,x _L ] ^T , x _i represents the ith transmitted symbol; H represents the sampling matrix; n represents the noise sampling value matrix, R _n =E(nn ^H ).

Step 2: Equalize the output y of the sampler, the equalizer output is

$\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Gy</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Hx</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

where G represents the equilibrium matrix. Here we use linear equalization algorithms with low complexity, namely the minimum mean square error (MMSE) algorithm, zero forcing (ZF) algorithm and matched filter (MF) algorithm, where

G _MMSE =H ^H (HH ^H +R _n ) ^-1 , (11)

G _ZF =(H ^H H) ^-1 H ^H , (12)

G _MF =H ^H . (13)

Step 3: Pair the Equalizer Output A decision is made to obtain the L data symbols at the transmission end.

Step 4: Repeat the steps from Step 1 to Step 3 for the sending data of Group 2 to Group M to complete the reception of all data symbols.

2. Receiver model of L=K

Consider a receiver model with L=K, as shown in Figure 11. For the receiver model shown in Figure 11, the main steps are as follows:

Step 1: Sampling the received signal r(t), then the output of the sampler is

y=Hx+n, (14)

Where y=[y ₁ ,y ₂ ,…,y _2K-1 ] ^T , y _i represents the sampling value at each sampling moment; x=[x ₁ ,x ₂ ,…,x _K ] ^T , _xi represents the ith transmission symbols; H represents the sampling matrix; n represents the noise sampling value matrix, R _n =E(nn ^H ).

Step 2: Equalize the output y of the sampler, the equalizer output is

$\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Gy</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Hx</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

where G represents the equilibrium matrix. Here we use linear equalization algorithms with low complexity, namely the minimum mean square error (MMSE) algorithm, zero forcing (ZF) algorithm and matched filter (MF) algorithm, where

G _MMSE =H ^H (HH ^H +R _n ) ^-1 , (16)

G _ZF ＝(H ^H H) ^-1 H ^H , (17)

G _MF =H ^H . (18)

Step 3: Pair the Equalizer Output A decision is made to obtain the K data symbols at the transmission end.

Step 4: Repeat the steps from Step 1 to Step 3 for the sending data of Group 2 to Group M to complete the reception of all data symbols.

So far, the receiving method in the signal transmission method of the present application has been processed.

Next, a specific example is used to illustrate the signal transmission method of the present application. Consider a 4-fold transmission signal with high spectral efficiency, and the schematic diagram of the transmission signal is shown in Figure 12.

At the sending end, first, every 4 data symbols are grouped. Then, serial-to-parallel conversion is performed on the 4 data symbols in the first group, and pulse shaping is performed on them respectively to form time-domain waveforms g _i (t), (i=1, 2, 3, 4). Finally, each time-domain waveform obtained in the previous step is delayed and added to obtain the time-domain waveform x(t) to be sent, and x(t) is sent out.

At the receiving end, firstly, the received waveform is sampled, then the output of the sampler is

y=Hx+n, (19)

Where y=[y ₁ ,y ₂ ,…,y ₇ ] ^T , y _i represents the sampling value at each sampling moment; x=[x ₁ ,x ₂ ,x ₃ ,x ₄ ] ^T , _xi represents the ith Send symbols; H represents a sampling matrix; n represents a matrix of noise sampling values, R _n =E(nn ^H ). If the transmitter adopts square wave shaping, then

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; =</span>{\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]}_{\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; )</span>$

Then, the output y of the sampler is equalized, and the equalizer output is

$\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Gy</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Hx</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; one</span>}<span\; class="notranslate">\; )</span>$

where G represents the equilibrium matrix. Here we use less complex linear equalization algorithms, namely the minimum mean square error (MMSE) algorithm, zero forcing (ZF) algorithm and matched filter (MF) algorithm. Finally, on the equalizer output Judgment is made to obtain the 4 data symbols at the transmission end.

Repeat the above steps for the 2nd to Mth groups of sending data to complete the transmission of all data symbols.

It can be seen from the above specific description of the signal transmission method in this application that in this application, at the sending end, firstly, the data symbols to be transmitted are grouped, and secondly, the grouped data symbols are passed through a pulse shaping filter to form a time-domain waveform, and then use The delayer delays the time-domain waveforms, and then uses the adder to add the delayed time-domain waveforms. Among them, in order to achieve the purpose of interference control, only a limited number of time-domain waveforms are selected each time Perform superposition, and finally send out the superimposed time-domain waveform. At the receiving end, we first sample the received time-domain waveform, then use a less complex linear equalization algorithm to perform equalization detection on the sampled signal, and finally judge the equalized data to obtain all the data at the sending end information. Compared with the traditional time-domain orthogonal model at the transmitting end, the present application has significantly improved spectral efficiency, and the artificially introduced intersymbol interference is controllable.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (6)

1. A signal transmission method, characterized in that, comprising: The data symbols to be transmitted are grouped, and each group includes L data symbols; wherein, L is the preset number of data symbols sent for each superimposition; For any group of data symbols, perform serial-to-parallel conversion on the L data symbols in the group and perform pulse shaping respectively, and perform different delays on the formed time-domain waveforms, and then superimpose the delayed time-domain waveforms after sending; Wherein, the delays of the K time-domain waveforms in any group of data symbols are less than T; K is the preset number of overlapping transmitted data symbols, L is greater than or equal to K, and T is the time length of each data symbol. 2. The method according to claim 1, characterized in that, said delaying each time-domain waveform formed comprises: When L>K, for the i-th data symbol in any group of data symbols, the corresponding delay time Wherein, K is the preset overlapping number of the time-domain waveforms; When L=K, for the i-th data symbol in any group of data symbols, its corresponding delay time ${\mathrm{\&tau;}}_i=(i-1)\frac{T}{K},(i=\mathrm{1,2},...,K).$ 3. The method according to claim 1 or 2, characterized in that the difference between L and K is smaller than a set threshold. 4. The method according to claim 3, characterized in that the threshold, L and K are determined according to the system's control requirements on inter-symbol interference. 5. The method according to claim 1 or 2, characterized in that the method further comprises: receiving the transmitted time-domain waveform, and performing sampling and equalization detection on the received signal to obtain each group of transmitted data symbols. 6. The method according to claim 5, wherein a minimum mean square error method, a zero-forcing method or a matched filtering method is used for the equalization detection.