Dynamic delay carrier aggregation phase compensation method based on wireless channel emulator

Abstract

The present invention relates to the field of communications and discloses a dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator, comprising the following steps: Step 1: setting the baseband sampling rate F according to the simulation requirements; s , channel bandwidth B, obtain the normalized code Doppler time Δt and M value according to the relative motion speed v of the two communicating parties; Step 2: calculate the true single tone value f0 and sampling rate F of the compensation signal according to the M value s1 , configure the NCO to generate a compensation signal with a frequency of f0; in step three, perform phase compensation at the intersection of the two channels of the carrier aggregation based on the compensation signal output by the NCO. Dynamically adjust the NCO output frequency based on changes in the relative motion speed v to complete dynamic delay carrier aggregation phase compensation. This invention can solve the phase discontinuity problem after compensation of the intersection of adjacent frequency bands during dynamic delay.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator. Background Art

[0002] Carrier aggregation is a common solution used by RF instruments to expand their signal processing bandwidth. Due to the limitations of analog-to-analog sampling rates, wireless channel emulators must aggregate multiple digital channels to form a signal processing channel with a larger bandwidth.

[0003] Taking two-channel aggregation as an example, the two digital domain channels are aggregated into one physical channel through a combiner, and the amplitude and phase characteristics of the spliced ​​channels must be consistent with those of a single channel.

[0004] The traditional method of dynamic delay compensation is to perform amplitude-frequency processing on each frequency band sub-channel through a digital filter, then overlap and aggregate each frequency band sub-channel through an aggregation digital filter, and finally ensure that the amplitude of the overlapping and aggregated frequency band sub-channels is flat through the design of the digital filter transition band parameters. This traditional solution can solve the amplitude and phase compensation of the intersection of adjacent frequency bands during static delay.

[0005] The solution to dynamic delay processing is to discard or copy data based on the dynamic delay changes between two moments. If phase compensation is performed based on the difference between adjacent moments, it will cause spurious compensation at the intersection, thus affecting the dynamic delay compensation effect. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the prior art and provide a dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator, comprising the following steps:

[0007] Step 1: Set the baseband sampling rate F according to simulation requirements s , channel bandwidth B, and the normalized code Doppler time Δt and M value are obtained according to the relative motion speed v of the communicating parties;

[0008] Step 2: Calculate the true single tone value f0 and sampling rate F of the compensation signal based on the M value s1 , configure NCO to generate a compensation signal with a frequency of f0;

[0009] Step 3: Perform phase compensation on the intersection of the two channels of carrier aggregation according to the compensation signal output by the NCO. Dynamically adjust the output frequency of the NCO according to the change of the relative motion speed v to complete the dynamic delay carrier aggregation phase compensation.

[0010] Furthermore, the baseband sampling rate F is set according to the simulation requirements. s , channel bandwidth B, and the normalized code Doppler time Δt and M value are obtained according to the relative motion speed v of the two communicating parties, including:

[0011] The normalized code Doppler time is:

[0012]

[0013] but

[0014]

[0015] Where c is the speed of light, and ceil() represents the ceiling function.

[0016] Furthermore, the actual single tone value f0 and sampling rate F of the compensation signal are calculated based on the M value. s1 , configure the NCO to generate a compensation signal with a frequency of f0, including:

[0017] The actual single tone value of the compensation signal is:

[0018]

[0019] The sampling rate is:

[0020]

[0021] Furthermore, the phase compensation is performed on the intersection of the two channels of the carrier aggregation according to the compensation signal output by the NCO, and the output frequency of the NCO is dynamically adjusted according to the change of the relative movement speed v, including controlling the digital control frequency synthesizer (NCO) to generate a single tone f0 related to the relative movement speed v, and multiplying the output single tone signal with the intersection of the two channels to achieve the purpose of compensation.

[0022] The beneficial effects of the present invention are as follows: The dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator proposed in this paper effectively solves the phase discontinuity problem at the intersection of adjacent frequency bands in dynamic delay scenarios by precisely controlling the generation and updating of compensation signals. This method utilizes a numerically controlled frequency synthesizer (NCO) to achieve precise phase control, facilitating modular implementation in a baseband FPGA and improving the performance of carrier aggregation in dynamic delay environments. Verified by simulation tests, this method excels in spurious suppression and signal quality improvement, providing strong support for the development of wireless channel emulation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the flow of a dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator;

[0024] Figure 2 This is a schematic diagram of the carrier aggregation solution for wireless channel emulator;

[0025] Figure 3This is the principle block diagram for dynamic delay implementation;

[0026] Figure 4 This is a schematic diagram of phase compensation data at the intersection of the spliced ​​frequency bands;

[0027] Figure 5 Schematic diagram of wave aggregation compensation data for dynamic delay scenarios;

[0028] Figure 6 Schematic diagram of reducing spurious compensation in dynamic delay scenarios;

[0029] Figure 7 This is the principle diagram of single-tone compensation in a dynamic delay scenario;

[0030] Figure 8 This is a comparison chart of single-tone compensation in a dynamic delay scenario;

[0031] Figure 9 Schematic diagram of the compensation tone of the dynamic delay carrier aggregation phase compensation method based on the wireless channel emulator;

[0032] Figure 10 Schematic diagram of the traditional carrier aggregation dynamic delay compensation solution;

[0033] Figure 11 Schematic diagram of dynamic delay carrier aggregation compensation solution. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0035] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0036] like Figure 1 As shown, the dynamic delay carrier aggregation phase compensation method based on the wireless channel emulator includes the following steps:

[0037] Step 1: Set the baseband sampling rate F according to simulation requirements s , channel bandwidth B, and the normalized code Doppler time Δt and M value are obtained according to the relative motion speed v of the communicating parties;

[0038] Step 2: Calculate the true single tone value f0 and sampling rate F of the compensation signal based on the M value s1 , configure NCO to generate a compensation signal with a frequency of f0;

[0039] Step 3: Perform phase compensation on the intersection of the two channels of carrier aggregation according to the compensation signal output by the NCO. Dynamically adjust the output frequency of the NCO according to the change of the relative motion speed v to complete the dynamic delay carrier aggregation phase compensation.

[0040] The baseband sampling rate F is set according to the simulation requirements. s , channel bandwidth B, and the normalized code Doppler time Δt and M value are obtained according to the relative motion speed v of the two communicating parties, including:

[0041] The normalized code Doppler time is:

[0042]

[0043] but

[0044]

[0045] Where c is the speed of light, and ceil() represents the ceiling function.

[0046] The actual single tone value f0 and sampling rate F of the compensation signal are calculated based on the M value. s1 , configure the NCO to generate a compensation signal with a frequency of f0, including:

[0047] The actual single tone value of the compensation signal is:

[0048]

[0049] The sampling rate is:

[0050]

[0051] The method performs phase compensation on the intersection of the two channels of the carrier aggregation according to the compensation signal output by the NCO, and dynamically adjusts the output frequency of the NCO according to the change of the relative motion speed v, including: controlling the digitally controlled frequency synthesizer (NCO) to generate a single tone f0 related to the relative motion speed v, and multiplying the output single tone signal with the intersection of the two channels to achieve the purpose of compensation.

[0052] Specifically, the present invention proposes a dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator, which can solve the phase discontinuity problem after dynamic delay compensation of adjacent frequency band intersections.

[0053] like Figure 2 The following is a schematic diagram of the carrier aggregation scheme for a wireless channel simulator. In the figure, B represents the maximum bandwidth in the digital domain, and f1 is the carrier frequency. In a dynamic delay scenario, assuming that the relative speed of the communicating parties is v at the current moment, the normalized code Doppler time caused by the relative motion is (used to characterize the dynamic delay)

[0054]

[0055] In order to achieve code Doppler, the traditional solution needs to process one sample point every M samples (if the two ends of the transmitter and receiver are close, one sample point will be discarded, and if they are far away, one sample point will be copied. This article takes close as an example).

[0056]

[0057] Among them F s Indicates the baseband sampling rate.

[0058] like Figure 3 The block diagram of the dynamic delay implementation principle shown in the figure causes the delay between two adjacent moments to change.

[0059] Because the sampling rate remains unchanged, the removed data is equivalent to an increase in the symbol rate, resulting in code Doppler. During carrier aggregation, the rightmost edge of digital channel 1 and the leftmost edge of digital channel 2 completely overlap, indicating a crossover point between the two channels.

[0060] Due to the dynamic delay function of the above-mentioned baseband, the phase discontinuity between the Mth code element and the first code element after elimination in the above figure will cause amplitude fluctuations when the intersection points of adjacent frequency bands are merged, so the splicing point of the carrier aggregation needs to be compensated.

[0061] The traditional compensation method is based on the phase difference between the rightmost frequency point of digital channel 1 and the leftmost frequency point of digital channel 2. Where T s =1 / F s .

[0062] Therefore, each time a point is removed, the subsequent compensation is achieved through cumulative compensation, and the phase compensation data is as follows: Figure 4 shown.

[0063] from Figure 4 It can be seen that the compensation value is a single tone, and the phase change has a step shape, which will introduce spurious signals, resulting in poor compensation effect under dynamic delay conditions. s =630MHz, B = 520MHz, then the rightmost tone of digital channel 1 is 260MHz, and the leftmost tone of digital channel 2 is -260MHz. When the test speed is v = 50000km / h, the compensation tone in traditional carrier aggregation in dynamic delay scenario is as follows: Figure 5 As shown:

[0064] The presence of spurious signals in the compensation phase will affect the signals around the splicing frequency, thus affecting the compensation accuracy. This paper proposes a dynamic delay compensation method to avoid spurious signals and thus improve the compensation accuracy.

[0065] like Figure 6The following figure shows a spurious reduction compensation solution for a dynamic delay scenario. The phase change of traditional compensation is the solid line. Spurious spurs arise from the sudden phase change from point B to point C. If the solid line ABC can be replaced by the dotted line AC to achieve a continuous phase change, spurious spurs will be reduced.

[0066] From the perspective of signal processing, in traditional dynamic delay scenarios, the compensation tone at the intersection of adjacent frequency bands is undersampled.

[0067] From the principle of the proposed dynamic delay code element, it can be seen that the compensation phase is equivalent to updating once every M-1, so the actual single tone value of the compensation signal is At the same time, the sampling rate of the single tone is

[0068] When the sampling rate of the signal processing F s When fixed, M is only related to the velocity v, so the phase compensation can be achieved through the numerically controlled frequency synthesizer (NCO). This forms a model for the phase compensation of the intersection point that is only related to the relative motion, which facilitates the modular implementation of the baseband FPGA in the wireless channel emulator. The compensation principle block diagram is shown in the figure. Figure 7 shown.

[0069] like Figure 8 The comparison diagram of single tone compensation in dynamic delay scenario is shown in the figure. After filtering the original phase change diagram and comparing it with the single tone compensation used in this paper, it is found that the only difference between the two is the initial phase, which also proves the correctness of the phase compensation scheme in this paper. The compensation single tone generated by the above method is as follows Figure 9 As shown, the single tone is directly generated without spurious.

[0070] Assumption F s =630MHz, B = 520MHz, then the rightmost tone of digital channel 1 is 260MHz, and the leftmost tone of digital channel 2 is -260MHz. When the test speed is v = 50000km / h, the compensation for traditional carrier aggregation in dynamic delay scenario and the compensation for carrier aggregation tone using the solution described in this article are as follows: Figure 10 Traditional carrier aggregation dynamic delay compensation solution and Figure 11 The two figures show the dynamic delay compensation scheme for carrier aggregation described in this article. In simulations, code offset represents the dynamic delay scenario, and the frequency points in the figures represent their relative positions to the crossover frequency. For single tones at 260 MHz and -260 MHz, the performance is identical when using code offset (dynamic delay) without compensation and when using code offset (no dynamic delay) with compensation.

[0071] When both code offset and crossover compensation are used, the traditional compensation solution introduces spurious signals, causing phase jitter at the dynamic delay compensation point at the 260MHz crossover. The maximum power point at the compensation point deviates from the intended location, causing interference with other frequency offsets (the circled solid line frequency point should be near 8990 + 3808 = 12798). Compared to the proposed solution, compensation occurs near the expected point (the deviation from the actual value is due to the frequency resolution of the fast Fourier transform).

Claims

1. A dynamic delay carrier aggregation phase compensation method based on a wireless channel emulator is characterized in that: The steps include: Step 1: Set the baseband sampling rate F according to simulation requirements s , channel bandwidth B, and the normalized code Doppler time Δt and M value are obtained according to the relative motion speed v of the communicating parties; Step 2: Calculate the true single tone value f0 and sampling rate F of the compensation signal based on the M value s1 , configure NCO to generate a compensation signal with a frequency of f0; Step 3: Perform phase compensation on the intersection of the two channels of the carrier aggregation according to the compensation signal output by the NCO. Dynamically adjust the output frequency of the NCO according to the change of the relative motion speed v to complete the dynamic delay carrier aggregation phase compensation. The baseband sampling rate F is set according to the simulation requirements. s , channel bandwidth B, and the normalized code Doppler time Δt and M value are obtained according to the relative motion speed v of the two communicating parties, including: The normalized code Doppler time is: but Where c is the speed of light, ceil() represents the ceiling function; The actual single tone value f0 and sampling rate F of the compensation signal are calculated based on the M value. s1 , configure the NCO to generate a compensation signal with a frequency of f0, including: The actual single tone value of the compensation signal is: The sampling rate is:

2. The method for dynamic delay carrier aggregation phase compensation based on a wireless channel emulator according to claim 1, characterized in that: The method of performing phase compensation on the intersection of the two channels of the carrier aggregation according to the compensation signal output by the NCO and dynamically adjusting the output frequency of the NCO according to the change of the relative motion speed v includes: The numerically controlled frequency synthesizer (NCO) is controlled to generate a single tone f0 related to the relative motion speed v, and the output single tone signal is multiplied by the intersection point of the two channels to achieve the purpose of compensation.

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