WO2012122908A1

WO2012122908A1 - Method and system for generating analogue radio frequency signal

Info

Publication number: WO2012122908A1
Application number: PCT/CN2012/071993
Authority: WO
Inventors: 刘龙; 刘刚; 邱海杰
Original assignee: 电信科学技术研究院
Priority date: 2011-03-11
Filing date: 2012-03-06
Publication date: 2012-09-20
Also published as: CN102122996B; CN102122996A

Abstract

Disclosed are a method and system for generating an analogue radio frequency signal. The method includes: up-sampling a baseband signal to obtain a first digital signal, with the sample rate for the up-sampling being N times the primary sample rate of the baseband signal, N > 1; after delaying the first digital signal and performing power attenuation thereon, carrying out down-sampling according to the primary sample rate to obtain a second digital signal; multiplying the second digital signal with a related factor to obtain a third digital signal, with the related factor containing a fading sequence reflecting multi-path fading caused by the channel multi-path environment; and converting the third digital signal obtained after multiplication into an analogue radio frequency signal for outputting. The method and system for generating an analogue radio frequency signal in the present invention realize modelling of the signal-over-channel process, and greatly reduce the complexity of modelling the signal-over-channel process while still obtaining good performance.

Description

The present invention claims the priority of the Chinese patent application filed on March 11, 2011 by the Chinese Patent Office, the application number is 201110059806.4, and the invention is entitled "Analog RF Signal Generation Method and System". This is incorporated herein by reference. TECHNICAL FIELD The present invention relates to the field of wireless communications, and in particular, to an analog radio frequency signal generating method and system for implementing signal over-channel modeling. BACKGROUND A wireless channel is a transmission medium for mobile communication, and all information is transmitted in a channel. The performance of the channel directly determines the shield of the communication. Therefore, it is usually necessary to understand the characteristics of the channel and accurately simulate it, and then simulate the signal. Simulation during transmission in the channel. The analog channel mainly determines the impulse response of the channel to be simulated, convolves the transmitted signal with the channel impulse response, simulates the transmission process of the signal in the channel, and implements the signal transmission test according to the analog signal transmission process. Wait for the purpose.

Generating a channel to simulate a real analog domain channel in the baseband digital domain is currently the mainstream implementation of channel simulation. There are two ways to simulate the transmission of a signal in a channel:

1) directly generating a channel impulse response of the digital domain according to the original sampling rate of the baseband signal, convolving the digital signal generated by the baseband with the generated channel impulse response, and converting the digital signal obtained by the convolution into an analog signal, simulating The radio frequency signal is transmitted in the channel.

The baseband signal is the signal from the source (information source, also called the transmitting terminal) that directly expresses the information to be transmitted, and the original electrical signal that is sent from the source without modulation (spectral shifting and transformation). The baseband signals of the communication system are generated in the digital domain. Each system has a specification that specifies the original sample rate of the baseband signal. The baseband signal has a low original sample rate, and the baseband signal is modulated to obtain an analog RF signal for transmission.

Taking multple input multiple output (MIMO) as an example, the signal transmission process in this way is expressed as follows:

-M,T _S )

Formula 1 )

Where _X (kT _s is a digital signal obtained by sampling the i^ signal at the original sampling rate, h(nT _s , kT _s , is a channel impulse response for generating a digital domain according to the original sampling rate of the baseband signal, J _s is the sampling interval according to the original sampling rate, A, "is a positive integer, J is the multipath number, A is the power attenuation of the /th diameter, 1≤/≤J, C is the reflection of the multipath baseband The correlation matrix of the correlation of signal transmission, & (« ^ is the fast decay sequence of the /th path, which is quantized according to the original sample rate The delay is the number of points.

It can be seen that the actual channel transmission signal is an analog radio frequency signal, and is used in the digital domain to generate a channel impulse response according to the original sample rate of the baseband signal, and the analog RF signal is transmitted in the channel, because the number of samples is small, so the scheme The complexity is low, but at the same time, due to the small number of samples, the signal of the digital domain is less realistic than the simulated RF signal and the channel of the digital domain with respect to the actual channel. Therefore, the channel impulse response time generated according to the original sampling rate is The resolution is also low. Due to the multipath characteristics of signal transmission, multipath aliasing may occur, which affects the modeling performance and makes it impossible to perform signal transmission tests more accurately.

2) generating a channel impulse response of the digital domain according to the sample rate after the sample rate is increased, and convolving the digital signal after the baseband signal is sampled with the generated ascending channel impulse response, After the high-frequency sample rate signal of the channel change, the high-frequency sample rate signal is outputted by the lower sample-like filter to output the digital signal at the original sample rate, and the digital-to-analog conversion circuit converts the output digital signal into an analog signal, thereby realizing the analog RF signal. The transmission process in the channel.

Ascending sample refers to the sample rate according to the increase of the set multiple of the original sample rate.

Taking multiple input multiple output MIMO as an example, the analog signal transmission process in this way is expressed as follows:

In this method, _up ) is a digital signal obtained by sampling the baseband signal at a rising rate, h(nT _{s up} , kT _{s υρ} , is a channel impulse response for generating a digital domain according to the sample rate, r _{s υρ} For the sample interval after ascending sample, k, « is a positive integer, J is the multipath number, _A is the power attenuation of the /th path, 1≤/≤J, C is the reflection of the multipath baseband signal transmission correlation For the relevant forming matrix, & («7 _up ) is the fast decay sequence of the /th path, ρ is the multiple of the ascending sample, and ^ is the delay of the first/strip diameter quantified according to the sample rate after the ascending sample. Points.

Since ^ / β is not necessarily an integer, it is not possible to directly generate equation (3), which requires a formula (2), and then approximates to obtain (3). Since ^ / β is not necessarily an integer, the equations (1) and (3) are not equivalent, and the interval after the ascending sample becomes smaller, and the process is closer to the true value.

Because the baseband signal and the channel have more samples, the scheme is closer to the actual analog signal and channel, which can effectively improve the time resolution of the channel impulse response, but at the same time, due to the large number of samples, When the sampling rate of the original sample (Ν is a multiple of the ascending sample, Ν>1) is increased, the complexity is twice that of the previous one, so the simulation of the transmission process in the channel is brought to a larger extent. difficult.

At the same time, for the scenario of multiple input and multiple output ΜΙΜΟ, the existing scheme generally has the same multiple amplification factor for multiple signals, so that when the bandwidth of multiple signals is different, the sampling rate of multiple signals is different. For channels with delay, the sampling rate of multiple signals is different, which will result in different quantized delay samples, and the frequency domain correlation will also be different, which will also affect the simulation of the transmission process of RF signals in the channel.

It can be seen that the disadvantages of the prior art are mainly that the complexity is low, the accuracy is low, or the accuracy is high. Higher, unable to achieve a good compromise between complexity and performance. SUMMARY OF THE INVENTION The present invention provides a method and system for generating an analog radio frequency signal, which is used to achieve a better compromise between complexity and performance over the modeling of the original signal over-channel.

The invention provides a method for generating an analog radio frequency signal, comprising:

The baseband signal is boosted to obtain a first digital signal, and the sampled sample rate is N times the original sample rate of the baseband signal, N>1;

After performing delay and power attenuation on the first digital signal, the original digital sample rate is decreased to obtain a second digital signal;

Multiplying the second digital signal by a correlation factor to obtain a third digital signal, the correlation factor including a fading sequence reflecting a radial fading of the channel;

The third digital signal obtained by multiplying is converted into an analog radio frequency signal output.

The invention also provides an analog radio frequency signal generating system, comprising:

a rising sample device for boosting a baseband signal to obtain a first digital signal, wherein the sample rate of the ascending sample is N times the original sample rate of the baseband signal, N>1;

a power attenuation and delay device, configured to perform delay and power attenuation on the first digital signal;

a descending sample device, configured to reduce a signal after delay and power attenuation according to the original sample rate, to obtain a second digital signal;

a fading sequence generator, configured to generate a fading sequence that reflects radial fading of the channel;

a multiplier, multiplying the second digital signal by a correlation factor to obtain a third digital signal, the correlation factor including a fading sequence;

And a converter, configured to convert the third digital signal obtained by multiplication into an analog RF signal output.

The method and system for generating an analog radio frequency signal provided by the present invention have the following beneficial effects: Compared with the prior art, under the premise of achieving better performance, the complexity of modeling the signal transmission channel is greatly reduced, which brings Great convenience. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a method for simulating a signal transmission process provided by the present invention;

2 is a structural diagram of a signal transmission process simulation system provided by the present invention;

3 is a structural diagram of a signal transmission process simulation system according to an embodiment of the present invention;

4 is a structural diagram of a polyphase filter according to an embodiment of the present invention; FIG. 5 is a cascade structure diagram of a multi-stage polyphase filter according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method and system for generating an analog radio frequency signal provided by the present invention will be described in more detail below with reference to the accompanying drawings and embodiments.

For the modeling of the transmission process of the signal in the channel, in order to obtain a better compromise between the complexity and the performance of the original modeling method, the present invention provides a method for generating an analog RF signal, as shown in FIG. 1, comprising:

Step S101, the baseband signal is upgraded to obtain the first digital signal, and the sample rate of the ascending sample is N times of the original sample rate of the baseband signal, N>1;

The baseband signals of the communication system are generated in the digital domain. Each system has a specification that specifies the original sample rate of the baseband signal, and the baseband signal has a lower original sample rate.

The multiplication number N is generally an integer and greater than 1, for the purpose of ascending the sample, and the first digital signal x obtained by the ascending sample (the time interval T _{s up of} kT _s is relatively short, wherein 3⁄4 _UP represents the sample Point, k is a positive integer.

Step S102, after performing delay and power attenuation on the first digital signal, reducing the sample according to the original sample rate to obtain a second digital signal;

The delay value for delaying the first digital signal X(3⁄4„p) and the power attenuation value for performing power attenuation are determined according to different communication system scenarios, and according to the existing specifications, corresponding delay values are obtained in different scenarios. And the power attenuation value, which will not be described in detail here.

In this step, the sample interval of the second digital signal is obtained by the sample drop, and the sample interval corresponding to the original sample rate is obtained. Step S103, multiplying the second digital signal by the correlation factor to obtain a third digital signal, where the correlation factor includes a fading sequence that reflects radial fading of the channel, and in the step, multiplying the second digital signal by the correlation factor, and After a digital signal is convolved, the channel impulse response is the same as that obtained by the original sample rate drop;

Since the sampling rate of the second digital signal is the original sampling rate, the complexity is greatly reduced, because the signal is subjected to the delay and the power attenuation after the signal is lifted, and the correlation coefficient is reflected with the channel characteristics. Multiply, therefore, the result obtained is the same as that achieved by converging the channel impulse response of the first digital signal with the original sample rate.

Step S104: Convert the third digital signal obtained by multiplication into an analog radio frequency signal and output, thereby completing modeling of the signal over channel.

The method for generating an analog radio frequency signal provided by the present invention greatly reduces the complexity of modeling compared with the prior art under the premise of achieving better performance.

The fading sequence that reflects the radial fading of the channel varies according to the channel model. Optionally, for the fast fading channel model, the fading sequence is fast fading, and of course, it can also be applied to the slow fading channel, and the fading sequence may have different values. . The signal transmission process has a multipath characteristic. Therefore, it is necessary to model the channel multipath transmission characteristic. Preferably, after delaying and power attenuation of the first digital signal in this embodiment, the original sampling rate is reduced. Obtaining the second digital signal specifically includes: determining the multipath number according to the multipath characteristic of the transmission environment; performing delay and power attenuation on the first digital signal according to the delay value and the power attenuation value of each path, according to the original The rate is reduced to obtain a second digital signal of multipath.

The channel impulse response convolved with the baseband signal is a multipath channel impulse response containing the delay value and power attenuation value for each path. That is, the channel impulse response reflects the multipath characteristic of the signal transmission, and the channel impulse response includes the number of paths, the delay value of each path, and the power attenuation value, and the first digital signal delay and power attenuation are used. The number of paths, the delay value and the power attenuation value of each path are the same. According to the existing specifications, there are corresponding path numbers in different scenarios, and the delay value and power attenuation value corresponding to each path. The baseband signal is a multi-baseband signal, and the correlation factor specifically includes a product of the correlation matrix C and the fading sequence reflecting the correlation of the multi-baseband signal transmission.

Taking the MIMO application scenario as an example, the method for generating an analog radio frequency signal provided by the present invention can be derived by using the formula for obtaining the above performance.

The actual channel impulse response h(t, τ) can be described as: h(t, r) = ∑ pi g _t (t)S(T - τ, )

Α is the power attenuation of the /th path, i ≤ / ≤ J, J is the multipath number, ^M c is the relevant forming matrix reflecting the correlation of multipath baseband signal transmission, & (t) is the fast decay of the Zth path Signal, ^ is the delay of the first path.

The actual process of signal X(T) over the channel can be described as:

r) * h(t, τ) = χ(τ) *∑ PI ^C SI ( ^-^) =∑ PI ^C SI (t)^― τ, )

In the embodiment of the present invention, the channel modeling is performed digitally. Therefore, as described above, in order to reduce the complexity of the implementation, the digital signal generated at the original sampling rate and the channel generated by the original sampling rate should be pulsed. The response is convolved, indicating: 3⁄4 under:

Formula 1 )

In order to obtain better simulation performance of the transmission process, the second method in the prior art is applied, that is, the digital signal after the sample is convolved in the channel module and the channel impulse response after the sample is obtained. The sorghum sample rate signal is changed, and the operation result is output at the original sample rate by the sputum sample filtering. Taking the multiple input multiple output MIMO as an example, the expression is as shown in the equations (2) and (3):

The physical model is based on the physical abstraction of the actual transmission loop. The Clarke model is a commonly used channel mathematical model for multipath fading, and the Jakes model generator is a simulation model for generating the Clarke model, which is a concrete implementation of the Clarke model. The resulting fast decay signal is generalized stationary and can better match the statistical properties in the Clarke model. Preferably, the fast decay sequence of each path in this embodiment can be generated by JAKES modeling. According to the above formula, it is found that the fast-fading sequence generated by the JAKES model generator is the same before and after the ascending sample, but the number of points generated is different, but there is a corresponding relationship between the points, and the JAKES model is generated after the ascending sample. The fast decay sequence generated by the device is downsampled, which is exactly the same as the fast decay sequence generated by the JAKES model generator when the original is not ascended. The main change brought by the ascending sample is that the delay on each path after the ascending sample is closer to the ideal value, that is, the sample rate influence is the resolution of the delay.

Thus, according to an embodiment of the present invention, the baseband signal is boosted to obtain a first digital signal, and after the delay and power attenuation of the first digital signal, the original digital sample rate is decreased, and the second digital signal is obtained. Multi-input and multi-output scenarios, considering multipath characteristics, should be formula (3)

Preferably, the baseband signal is a multi-baseband signal, and multiplying the second digital signal by the correlation factor comprises: multiplying the second digital signal of each path by (: and the fast-fading sequence of the path, performing The multipath superposition is performed to obtain a third digital signal, that is, the result of the above formula (3) is obtained, so that the present invention achieves an improvement in resolution with greatly reduced complexity.

The above is only an example of a channel model. There are different channel models for different scenes. In different channel models, the specific values of each parameter in the above formula may be different. The process of determining each parameter in the above formula is existing. Technology, no longer detailed here.

In the MIMO scenario, in order to solve the problem that the channel frequency selectivity is different due to the inconsistent sampling rate in different bandwidths, in the embodiment, the baseband signal is upgraded, which specifically includes: according to the bandwidth of each baseband signal. , determining the ascending multiple of each baseband signal; ascending the baseband signal according to the determined amplification factor multiple, so that the sampling rate of the multi-baseband signal is the same, so the bandwidth is larger, so The smaller the multiplier, the smaller the bandwidth and the larger the magnification.

The signal transmission method provided by the above embodiments of the present invention proposes a new scheme for signal over-channel modeling, which models a MIMO channel based on a correlation matrix method. The invention only needs to raise the signal, and then the signal after the ascending sample is delayed and the power is attenuated, and then the sample is multiplied by the fading without the ascending sample to obtain the signal after the channel is changed. The formula derivation shows that the performance of the scheme is equivalent to the second scheme, but the complexity is greatly reduced. At the same time, considering the consistency of the sample rate under various bandwidths and the influence of the multiples on the complexity and performance of the system, it is necessary to determine the multiple of the sample. For example, for channel modeling, 8 or 16 times of the upgrade is a good compromise between its performance and complexity, so the determinable sample-up scheme is: 8 times the 20M bandwidth, 10M bandwidth rises. The sample is 16 times, and the 5M bandwidth is 32 times higher. Similar applications can be obtained for other system bandwidths.

An embodiment of the present invention further provides an analog radio frequency signal generating system, as shown in FIG. 2, including:

a sample-up device for lifting a baseband signal to obtain a first digital signal, the sample rate of the ascending sample is N times the original sample rate of the baseband signal, N>1, preferably, ascending sample The device specifically uses an interpolation filter to design the order of the interpolation filter according to the multiple of the ascending sample. When the magnification is larger, the required interpolation filter has a higher order;

The power attenuation and delay device is configured to perform delay and power attenuation on the first digital signal, and the specific delay value and power attenuation value are determined according to different scenarios. When considering multi-level characteristics of signal transmission, preferably, Power attenuation And the delay device is specifically configured to perform delay and power attenuation on the first digital signal according to the delay value and the power attenuation value of each path according to the multipath number;

The descending sample device is configured to reduce the signal after the delay and the power attenuation according to the original sampling rate to obtain a second digital signal. Preferably, the lifting device is specifically configured with a decimation filter, for the case of multipath , for each path delay and power attenuation signal, according to the original sample rate drop sample, to obtain a multi-path second digital signal;

a fading sequence generator for generating a fading sequence reflecting a radial fading of the channel, the generated fading sequence being different according to a channel model;

a multiplier, multiplying the second digital signal by a correlation factor to obtain a third digital signal, the correlation factor including the fading sequence, and the result of multiplying the second digital signal by the correlation factor and the first digital signal convolved by the channel rush After the response, the result is the same as that of the original sample rate. In the MIMO scenario, the correlation factor is determined as shown in the above embodiment, and the application scenario is not limited to the MIMO scenario. In the scenario, the correlation factor can also be determined according to the above formula derivation;

The converter is configured to convert the third digital signal obtained by multiplication into an analog RF signal output, and complete the modeling of the signal over-channel, so that the signal transmission process simulation can be used to measure various performances of the signal transmission.

Due to the multipath characteristic of the signal transmission, the power attenuation and delay device is specifically configured to delay and power the first digital signal according to the delay value and the power attenuation value of each path according to the multipath number of the transmission. Attenuation; Degradation device, specifically for each path delay and power attenuation signal, according to the original sample rate drop sample, to obtain a multi-path second digital signal. The fading sequence generator is specifically configured to generate a multipath fading sequence that reflects radial fading of the multipath channel. The multiplier is specifically configured to continuously multiply the second digital signal of each path by c and a fading sequence of the path; the system further includes: a multipath adder for multipath superimposing the signal output by the multiplier to obtain The third digital signal.

As shown in FIG. 3, the ascending sample device specifically uses an interpolation filter, and the downsample device specifically extracts the filter. For the MIMO scene, the system further includes: a correlation matrix former for generating a multi-baseband signal transmission Correlation-related forming matrix (:, using the correlation matrix former to generate the relevant forming matrix (: for the prior art, not detailed here; the fading sequence is specifically a fast fading sequence, and the fading sequence generator is specifically for multipath fast fading a fast fading sequence generator for modelling the channel for generating a fast fading sequence for each path. Preferably, the fast fading sequence generator is specifically a Jakes model generator for modelling a multipath fading channel; In the case, the multiplier is specifically configured to continuously multiply the second digital signal of each path by (: and a fast decay sequence of the path; and a multipath adder for multipath superimposing the signal output by the multiplier to obtain The third digital signal, the result of equation (3).

Since the conventional interpolation filter has many zero points, there are many meaningless operations if the general interpolation filter is used. In order to reduce the amount of calculation, in the embodiment, the interpolation filter uses a polyphase filter composed of a plurality of sub-filters, and when the multiplier is N, the interpolation is performed by N times, and the N sub-filters are used. The polyphase filter consisting of the device can reduce the amount of calculation to the original 1/N. In order to use the minimum memory structure, multiple converters can be used. For example, four times interpolation can be used to construct the structure shown in FIG. _ω Ο) is the input digital signal, / 0)~; ζ(11) is four The coefficients of the sub-filters, /z(0)~; each line in z(ll) corresponds to the coefficient of one sub-filter. After the multiplier multiplies the input signal by the coefficient of one sub-filter, the rotary switch points to the next one. Subfilter, adder adds the multiplier outputs to get the output signal x («').

In addition, since the different system bandwidths are different, for example, consider 20M, 10M and 5M systems. When the ascending sample factor is large, the required filter order is high, and the multi-stage interpolation filter can be used to reduce the amount of calculation. Alternatively, the interpolation filter uses a polyphase filter. . The structure of the multi-stage interpolation filter is used to raise and sample each baseband signal according to the amplification factor determined according to the bandwidth of each baseband signal, so that the multi-baseband signal is upgraded. The sampling rate is the same. Multi-stage cascaded interpolation filters are suitable for baseband signal boosting in single-bandwidth and multi-bandwidth communication systems.

As shown in Fig. 5, when the bandwidth of the multi-baseband signal is 20MHz, 10MHz and 5MHz, respectively, the up-and-down device uses a three-stage cascaded interpolation filter, and the first-stage interpolation filter realizes 8 times ascending sample. The second-stage interpolation filter realizes 2 times ascending sample, and the third-stage interpolation filter realizes 2 times ascending sample. The filter stages and coefficients can be flexibly configured as needed. The scheme can be applied to any single-bandwidth or multi-bandwidth system. For single-bandwidth, it can be upgraded step by step. For multi-bandwidth, by designing the scale-up multiples realized at each level, the output rate from different levels is always achieved. For digital signals, only the number of filter stages and the coefficients of the optimized filter need to be increased or decreased. Here, only the 20M, 10M, and 5M system bandwidths are illustrated, and the effective multiplexing of the filters in the multi-bandwidth system is also explained. Therefore, for multi-bandwidth applications of interpolation filters, multiple filter cascades can be used, and the filter stages and coefficients can be flexibly configured to achieve filter multiplexing. For single-bandwidth applications of interpolation filters, high-order filtering can use multiple filter cascades, and the filter stages and coefficients can be flexibly configured.

The application of multi-stage filters takes into account the reusability of the filters at different system bandwidths and effectively reduces the number of filters required for high-magnification samples. The polyphase filter effectively reduces the amount of computation of the convolution, and the combined use of the two further reduces the complexity of the implementation.

The invention proves that the requirement of increasing the channel resolution of the channel impulse response can be satisfied by simply formulating the signal without lifting the fading sample, and using multi-stage and polyphase filter phases. The combined approach further reduces the complexity and also solves the problem of different channel frequency selectivity caused by inconsistent sampling rates under different system bandwidths.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware. Moreover, the present invention can be embodied in the form of a computer program product embodied on one or more computer-usable storage interfaces (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It should be understood that each flow in the flowchart and/or block diagram can be implemented by computer program instructions. And/or blocks, and combinations of flows and/or blocks in the flowcharts and/or block diagrams. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

Although the preferred embodiment of the invention has been described, it will be apparent to those of ordinary skill in the art that <RTIgt; Therefore, the appended claims are intended to be construed as including the preferred embodiments and the modifications

It is apparent that those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, it is intended that the present invention cover the modifications and modifications of the inventions

Claims

Rights request

A method for generating an analog radio frequency signal, comprising:

The method according to claim 1, wherein after the delaying and power attenuation of the first digital signal, the second digital signal is obtained according to the original sampling rate, which specifically includes:

The multipath number is determined according to the multipath characteristic of the transmission environment;

After delaying and power attenuating the first digital signal according to the delay value and the power attenuation value of each path, the second digital signal of the multipath is obtained according to the original sample rate drop.

The method according to claim 1 or 2, wherein the baseband signal is a multiplexed baseband signal, and the correlation factor specifically includes an associated shaping matrix C and a fading sequence that reflect the correlation of the multiplexed baseband signal transmission. product.

The method of claim 3, wherein the fading sequence is specifically a multipath fading sequence that reflects radial fading of the multipath channel, and multiplying the second digital signal by a correlation factor, specifically:

After multiplying the second digital signal of each path by (: and the fading sequence of the path, multipath superposition is performed to obtain a third digital signal.

The method according to claim 1 or 2, wherein the fading sequence is specifically a fast fading sequence, and the fast fading sequence is generated by a fast fading model generator for performing model simulation on a multipath fast fading channel.

The method according to claim 1 or 2, wherein the stepping up the baseband signal comprises: upgrading the baseband signal by using a polyphase filter composed of a plurality of subfilters kind.

The method according to claim 1 or 2, wherein the baseband signal is a multi-baseband signal, and the baseband signal is upgraded, specifically comprising:

Determining the multiple of each baseband signal according to the bandwidth of each baseband signal;

Each baseband signal is boosted and sampled according to the determined amplification factor multiple, so that the sampling rate of the multi-baseband signal is the same when the signal is raised.

8. The method according to claim 1 or 2, characterized in that the baseband signal is boosted by a multi-stage cascaded interpolation filter.

9. The method of claim 8, wherein the baseband is implemented by a multi-stage cascaded interpolation filter Signal boost, suitable for single bandwidth and multi-bandwidth communication systems.

10. An analog radio frequency signal generating system, comprising:

The system according to claim 10, wherein the power attenuation and delay device is specifically configured to delay the value and the power attenuation value of each of the first digital signals according to the number of multipaths transmitted. Performing delay and power attenuation; the downsampling device is specifically configured to delay the signal after each path delay and power attenuation, and obtain a multipath second digital signal according to the original sample rate .

The system of claim 10 or 11, wherein the baseband signal is a multi-baseband signal, the system further comprising:

a correlation matrix former for generating a correlation molding matrix c reflecting a multi-baseband signal transmission correlation; the multiplier is specifically configured to continuously multiply the second digital signal by a C and a fading sequence.

13. The system of claim 12, wherein the fading sequence generator is specifically configured to generate a multipath fading sequence that reflects radial fading of the multipath channel.

The multiplier is specifically configured to continuously multiply the second digital signal of each path by C and a fading sequence of the path; the system further includes:

The multipath adder is configured to multipath superimpose the signal output by the multiplier to obtain a third digital signal.

The system according to claim 10 or 11, wherein the fading sequence is specifically a fast fading sequence, and the fading sequence generator is specifically a fast fading model generator for performing model simulation on a multipath fast fading channel. .

The system according to claim 10 or 11, wherein the lift-up device is a polyphase filter composed of a plurality of sub-filters, and the down-sample device is a decimation filter.

The system according to claim 10 or 11, wherein the lifting device is specifically configured to perform a lifting of each baseband signal according to a multiple of the ascending sample determined according to the bandwidth of each baseband signal. , the sampling rate is the same when the multi-baseband signal is raised.

17. System according to claim 10 or 11, characterized in that said ascending sample device is a multi-stage cascaded interpolation filter.

18. The system of claim 17 wherein said multi-stage cascaded interpolation filter is adapted for baseband signal upsampling of single bandwidth and multi-bandwidth communication systems.