Adaptive adjustment method for multi-carrier waveform parameters of communication system

[0048] Example 1

[0049] Please refer to figure 1 , an adaptive adjustment method for multi-carrier waveform parameters of a communication system, comprising the following steps:

[0050] S1, obtain the service quality requirement of the user and the channel environment information fed back by the terminal receiver; the service quality requirement includes requirements for bit error rate and data transmission rate; the channel environment information includes the signal-to-noise ratio of the channel and the data transmission rate. Puller frequency shift parameter;

[0051] S2, matching a set of waveform parameter control factors closest to the channel environment information from a preset codebook that reflects the relationship between quality of service and waveform parameter control factors and waveform parameters;

[0052] S3, according to the waveform parameter control factor matched in the step S2, match a waveform parameter set that meets the quality of service requirement from the codebook;

[0053] S4, adjust the waveform parameters of the base station transceiver of the communication system according to the matched waveform parameter set.

[0054] Compared with the prior art, the present invention mainly uses the bit error rate of the system as a measurement index, and through the proposed adaptive waveform parameter adjustment scheme, the waveform parameter control factors, waveform parameter sets, and service quality requirements are constructed as a searchable index. In the codebook, the base station can find the waveform parameters that meet the current channel environment and service quality requirements according to the codebook, and then adjust the parameters of the transmission waveform adaptively; it realizes the flexible configuration of the transmission sent by the base station to the terminal on the wireless channel. The effect of the waveform can meet the user's bit error rate requirements under different moving speeds, and can well resist the impact of Doppler frequency shift on transmission quality. At the same time, under different SNR, it can also stabilize the bit error rate. below the user's target value.

[0055] Specifically, the adjustable waveform parameters include a cyclic prefix (Cyclic Prefix, CP) and a subcarrier spacing of the waveform.

[0056] Example 2

[0057] see figure 1 , an adaptive adjustment method for multi-carrier waveform parameters of a communication system, comprising the following steps:

[0058] S1, obtain the service quality requirement of the user and the channel environment information fed back by the terminal receiver; the service quality requirement includes requirements for bit error rate and data transmission rate; the channel environment information includes the signal-to-noise ratio of the channel and the data transmission rate. Puller frequency shift parameter;

[0059] S2, matching a set of waveform parameter control factors closest to the channel environment information from a preset codebook that reflects the relationship between quality of service and waveform parameter control factors and waveform parameters;

[0060] S3, according to the waveform parameter control factor matched in the step S2, match a waveform parameter set that meets the quality of service requirement from the codebook;

[0061] S4, adjust the waveform parameters of the base station transceiver of the communication system according to the matched waveform parameter set;

[0062] see figure 2 , the codebook is recorded as an array CF{SNR(S), Doppler(D)} with the waveform parameter control factors including the signal-to-noise ratio of the channel and the Doppler frequency shift parameter, which can be used as the first parameter in the codebook column data; the adjustable waveform parameter set is recorded as an array N{Subcarrier Spacing(SC), CP length(CP)}, which can be used as the first row of data in the codebook; to include bit error rate and data transmission rate As the quality of service, it is recorded as an array QoS{Bit Error Rate(B), Rate(R)}, as the data in the middle of the codebook.

[0063] Further, in the step S2, with the channel environment information CF{S UE ,D UE } The closest waveform parameter control factor is designed to satisfy:

[0064] {S UE ,D UE }≡{S i ,D i };

[0065] Among them, i∈{1,…,n}, i is the subscript of the waveform parameter control factor, n is the number of groups of the waveform parameter control factor.

[0066] Further, in the step S3, meet the quality of service requirements QoS{B UE ,R UE } waveform parameter set N i {SC i , CP i }, designed to meet the following quality of service requirements:

[0067] B i ≤B UE;

[0068] R i ≥R UE;

[0069] Among them, i∈{1,…,m}, i is the subscript of the waveform parameter set, m is the number of groups of the waveform parameter set number.

[0070] see next image 3 :

[0071] As a preferred embodiment, if several groups of waveform parameter sets that meet the quality of service requirements are matched in step S3; then the matched waveform parameter sets are further selected according to specific application scenarios:

[0072] If the specific application scenario pays more attention to the reliability of the communication system, the waveform parameter set with the lowest bit error rate in the matching result of step S3 is preferentially selected for adjustment in step S4;

[0073] If the specific application scenario pays more attention to the data transmission rate of the communication system, the waveform parameter set with the largest data transmission rate in the matching result in step S3 is preferentially selected for adjustment in step S4.

[0074] As a preferred embodiment, if the waveform parameter set that simultaneously meets the quality of service requirements cannot be matched in step S3; then the matched waveform parameter set is further selected according to the specific application scenario:

[0075] If the specific application scenario pays more attention to the reliability of the communication system, the waveform parameter set that meets the bit error rate requirement is firstly screened, and then the waveform parameter set that meets the bit error rate requirement has the largest data transmission rate for the step S4. to adjust;

[0076] If the specific application scenario pays more attention to the data transmission rate of the communication system, first select the waveform parameter set that meets the data transmission rate requirements, and then select the waveform parameter set that meets the data transmission rate requirements with the smallest bit error rate for the above steps. S4 is adjusted.

[0077] As a preferred embodiment, if the waveform parameter set that meets the quality of service requirement cannot be matched in the step S3; then the matched waveform parameter set is further selected according to the specific application scenario:

[0078] If the specific application scenario pays more attention to the reliability of the communication system, the waveform parameter set with the smallest bit error rate is preferentially selected for adjustment in step S4;

[0079] If the specific application scenario pays more attention to the data transmission rate of the communication system, the waveform parameter set with the largest data transmission rate requirement is preferentially selected for adjustment in step S4.

[0080] Example 3

[0081] A communication system, comprising a terminal transceiver and a base station transceiver, the terminal transceiver and the base station transceiver realize the adjustment of the waveform parameters of the base station transceiver using the adaptive adjustment method of the multi-carrier waveform parameters of the communication system in Embodiment 1 or 2. adaptive adjustment.

[0082] As a preferred embodiment, the base transceiver station obtains the channel environment information in the following manner:

[0083] see Figure 4 , the terminal transceiver performs channel estimation on the data sent by the base station transceiver including removing CP and Fourier transform, and obtains channel environment information including the signal-to-noise ratio of the channel and the Doppler frequency shift parameter, And at the MAC layer, the channel environment information is mapped to the uplink control channel, and after coding and modulation, the operations of adding CP and inverse Fourier transform are performed, and the generated feedback signal is sent to the base station transceiver through the uplink control channel, which is the base station transceiver. Provide reference for adjusting waveform parameters.

[0084] Further, the base transceiver station performs adaptive adjustment of waveform parameters in the following manner:

[0085] see Figure 5 , the base station transceiver performs the operations of removing CP and Fourier transform on the signal sent from the terminal transceiver, performs channel estimation and channel equalization, and demodulates the channel environment information fed back by the terminal transceiver , perform decoding; transmit the decoded channel environment information to the MAC layer, and perform the steps in the method for adaptive adjustment of multi-carrier waveform parameters of the communication system in the MAC layer to perform adaptive adjustment of waveform parameters.

[0086] In the simulation experiment, the transmission waveform is OFDM, the modulation method is QPSK, the number of FFT points is 1024, and the subcarrier spacing is 15kHz. see Image 6 , the signal-to-noise ratio (SNR) is fixed at 10dB, the moving speed of the user terminal is changed, that is, the value of the Doppler frequency shift is changed, and the communication system without the adaptive adjustment scheme of waveform parameters is compared with the communication system with the adaptive adjustment scheme of waveform parameters. The bit error rate BER. It can be seen from the simulation results in the figure that when the moving speed of the terminal is larger and the Doppler frequency shift is larger, the BER of the communication system without the waveform parameter adaptive adjustment scheme will increase accordingly, while the waveform parameter automatic adjustment scheme is implemented. The BER of the communication system adapted to the adjustment scheme is not greatly affected. On the whole, the BER of the communication system without the waveform parameter adaptive adjustment scheme fluctuates greatly, and the communication quality is greatly affected by the moving speed of the terminal, while the BER of the communication system with the waveform parameter adaptive adjustment scheme is basically maintained at 10. -3 Up and down, it is relatively stable and will not be affected too much by the moving speed of the terminal. At the same time, the BER of the communication system without the waveform parameter adaptive adjustment scheme is also higher than the BER of the communication system with the waveform parameter adaptive adjustment scheme implemented. Therefore, the scheme of adaptive adjustment of waveform parameters can not only improve the communication quality of the communication system, but also allow the system to better resist the Doppler frequency shift caused by the rapid movement of the terminal.

[0087] refer to Figure 7 , fix the Doppler frequency shift to 150Hz, change the size of SNR, and compare the BER of the communication system without the waveform parameter adaptive adjustment scheme and the communication system with the waveform parameter adaptive adjustment scheme implemented. It can be seen from the simulation results in the figure that the BER of the communication system without the waveform parameter adaptive adjustment scheme is higher than that of the communication system with the waveform parameter adaptive adjustment scheme implemented. At the same time, the smaller the SNR, the higher the BER of the communication system without the waveform parameter adaptive adjustment scheme, and the worse the communication quality, while the BER of the communication system with the waveform parameter adaptive adjustment scheme is less affected, which is basically maintained at 10 -4 Up and down, it is relatively stable and will not be affected too much by SNR changes. Therefore, the scheme of adaptive adjustment of waveform parameters can not only improve the communication quality of the communication system, but also enable the system to maintain a high communication quality in different channel environments.

[0088] This embodiment proposes a waveform parameter adaptive adjustment scheme for different scene requirements and service quality requirements, and designs corresponding terminal transceivers and base station transceivers based on the OFDM baseband processing flow. The terminal estimates the channel environment, and feeds back the waveform parameter control factors to the base station through the uplink control channel. Adjust accordingly, so as to achieve a more flexible air interface design. The simulation results verify the effectiveness of the scheme, which has strong engineering implementation significance.