Method and system for adjusting feedback parameters in channel state information

Abstract

The invention provides a method and system for adjusting a feedback parameter in channel state information, and the method comprises the steps: calculating a channel capacity based on a channel state information reference signal, and obtaining an initial feedback parameter based on the channel capacity; a2, calculating a capacity ratio based on the channel capacity of each transmission layer; averaging the capacity ratios calculated for continuous preset times to obtain an average capacity ratio; counting an average signal-to-noise ratio in a preset time window before the time slot where the current channel state information reference signal is located; and after updating the initial feedback parameter based on the average capacity ratio and the average signal-to-noise ratio, forming updated channel state information based on the updated feedback parameter, and reporting the updated channel state information to the base station. The channel state information is adjusted through a statistical method, the problem that the channel state information cannot be completely matched with the actual downlink PDSCH decoding capability is solved, and the more real decoding capability of the terminal is better fed back to the base station in an external field.

Description

Technical Field

[0001] The present invention relates to the field of new wireless technologies and wireless communication technologies, and in particular to a method and system for adjusting feedback parameters in channel state information. Background Art

[0002] In current 5G wireless communication systems, the base station requires the network to use the CSI-RS signal (Channel State Information Reference Signal) to estimate the current channel quality. The base station then uses the Channel Quality Indicator (CQI) and Rank Indicator (RI) to provide feedback to the base station, informing the UE (user equipment) of the current channel quality. The base station then determines the code rate and transport layer for scheduling the UE's data channel based on the CQI and RI feedback from the UE. A higher code rate and a higher transport layer yield a higher data rate, but also places greater demands on the UE's decoding capabilities.

[0003] The protocol does not restrict how the UE uses the CSI-RS signal to calculate the CQI; implementation depends entirely on the UE's physical layer algorithm. Currently, the most popular algorithm used by major UE chip manufacturers uses CSI-RS to calculate the channel capacity or signal-to-noise ratio (SNR) corresponding to different transmission layers. When the channel capacity or SNR is at its maximum, the maximum RI and the corresponding CQI are selected as the RI and CQI reported by the UE. The base station adjusts the MCS value of the PDSCH channel used to schedule the UE based on the CQI reported by the UE. If the CQI reported by the UE is too low, the required rate may not be met. If it is too high, exceeding the UE's decoding capability, bit errors will occur. When the bit error rate is severe, the base station may even release the UE, causing the network to drop.

[0004] Field measurements have shown that the CQI and RI values calculated directly from CSI-RS signals do not match the UE's decoding capabilities in complex channel environments and cannot truly reflect the UE's actual decoding capabilities. The reasons are as follows:

[0005] (1) Channel correlation exists. Channel correlation is determined by the spatial characteristics of the channel and the configuration of the antenna array. Since the channel is affected by signal transmission, diffraction, interference, etc., there is a certain spatial correlation between the elements in the channel matrix. This correlation will cause the rank of the channel matrix to decrease, thereby affecting the communication performance of the system. Moreover, as time goes by, the state of the channel will continue to change. Therefore, there will be a certain temporal correlation between the elements in the channel matrix. This correlation will make the prediction of the channel matrix more difficult. The mapping table from the UE-side channel capacity to the CQI may not match.

[0006] (2) Due to the complexity of wireless channels, there may be inter-layer interference. The result of selecting RI reporting based on the principle of maximizing capacity may fluctuate, thereby affecting the stability of the downlink rate. Summary of the Invention

[0007] Based on the above problems, the present invention provides a method for adjusting feedback parameters in channel state information, aiming to solve the problem in the prior art that the reported channel state information and the actual downlink PDSCH decoding capability cannot fully match.

[0008] The present invention provides a method for adjusting feedback parameters in channel state information, comprising:

[0009] Step A1, calculating the channel capacity based on the channel state information reference signal, and obtaining an initial feedback parameter based on the channel capacity;

[0010] Step A2, calculating a capacity ratio based on the channel capacity of each transmission layer;

[0011] Step A3, averaging the capacity ratio values calculated for a preset number of consecutive times to obtain an average capacity ratio value;

[0012] Step A4, calculating the average signal-to-noise ratio in a predetermined time window before the time slot where the current channel state information reference signal is located;

[0013] Step A5: After updating the initial feedback parameters based on the average capacity ratio and the average signal-to-noise ratio, updated channel state information is generated based on the updated feedback parameters and reported to the base station.

[0014] Furthermore, in step A2, the ratio of the maximum value to the minimum value of the channel capacity of each transmission layer is calculated as the capacity ratio.

[0015] Furthermore, the feedback parameter includes a channel quality indicator;

[0016] In step A5, a channel correlation is determined based on the average capacity ratio, and a corresponding channel quality indicator is selected based on the channel correlation to replace the initial channel quality indicator.

[0017] Further, the feedback parameter includes a rank indication;

[0018] In step A5, a penalty factor for the rank indication is selected according to the average capacity ratio and the average signal-to-noise ratio, and an updated rank indication is obtained based on the penalty factor for the rank indication, and the initial rank indication is replaced.

[0019] Furthermore, in step A5, the selection rule of the penalty factor of the rank indication is as follows:

[0020]

[0021] Among them, RI_punish_factor is the penalty factor of rank indication, snr is the average signal-to-noise ratio, and ratio is the average capacity ratio;

[0022] Among them, a <b<c,α<β<γ,th1> th2>th3.

[0023] A system for adjusting feedback parameters in channel state information, applied to a terminal, includes:

[0024] A channel capacity calculation module, configured to calculate the channel capacity based on the channel state information reference signal and obtain an initial feedback parameter based on the channel capacity;

[0025] a capacity ratio calculation module, connected to the channel capacity calculation module, for calculating the capacity ratio based on the channel capacity of each transmission layer;

[0026] A capacity ratio statistics module, connected to the capacity ratio calculation module, is used to average the capacity ratios calculated for a preset number of consecutive times to obtain an average capacity ratio;

[0027] A signal-to-noise ratio statistics module is used to count the average signal-to-noise ratio in a predetermined time window before the time slot where the current channel state information reference signal is located;

[0028] The parameter update module is connected to the capacity ratio statistics module and the signal-to-noise ratio statistics module respectively, and is used to update the initial feedback parameters based on the average capacity ratio and the average signal-to-noise ratio, and then form updated channel state information based on the updated feedback parameters and report it to the base station.

[0029] Furthermore, the capacity ratio calculation module calculates the ratio of the maximum value to the minimum value of the channel capacity of each transmission layer as the capacity ratio.

[0030] Furthermore, the feedback parameter includes a channel quality indicator;

[0031] The parameter updating module is used for determining the channel correlation based on the average capacity ratio, and selecting a corresponding channel quality indicator based on the channel correlation to replace the initial channel quality indicator.

[0032] Further, the feedback parameter includes a rank indication;

[0033] The parameter updating module is used to select a penalty factor of the rank indication according to the average capacity ratio and the average signal-to-noise ratio, obtain an updated rank indication based on the penalty factor of the rank indication, and replace the initial rank indication.

[0034] Furthermore, the parameter update module selects the penalty factor for the rank indication as follows:

[0035]

[0036] Among them, RI_punish_factor is the penalty factor of rank indication, snr is the average signal-to-noise ratio, and ratio is the average capacity ratio;

[0037] Among them, a <b<c,α<β<γ,th1> th2>th3.

[0038] The beneficial technical effect of the present invention is that: the present invention reflects the volatility of the terminal signal in the recent time by statistically analyzing the average of the channel capacity ratios of each transmission layer and the average signal-to-noise ratio in the recent time, and adjusts the channel state information through this statistical method to solve the problem that the channel state information and the actual downlink PDSCH decoding capability cannot be fully matched, so that the terminal's more realistic decoding capability can be better fed back to the base station in the field, reducing the problem of large-area bit errors or abnormal bit error rate fluctuations of the terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow chart of the steps of a method for adjusting feedback parameters in channel state information according to the present invention;

[0040] Figure 2 The figure is a module diagram of a system for adjusting feedback parameters in channel state information according to the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0044] See also Figure 1 The present invention also provides a method for adjusting feedback parameters in channel state information, comprising:

[0045] Step A1, calculating the channel capacity based on the channel state information reference signal, and obtaining an initial feedback parameter based on the channel capacity;

[0046] Step A2, calculating a capacity ratio based on the channel capacity of each transmission layer;

[0047] Step A3, averaging the capacity ratio values calculated for a preset number of consecutive times to obtain an average capacity ratio value;

[0048] Step A4, calculating the average signal-to-noise ratio in a predetermined time window before the time slot where the current channel state information reference signal is located;

[0049] Step A5: After updating the initial feedback parameters based on the average capacity ratio and the average signal-to-noise ratio, updated channel state information is generated based on the updated feedback parameters and reported to the base station.

[0050] The present invention reflects the volatility of terminal signals in the recent period by statistically analyzing the average channel capacity ratio and average signal-to-noise ratio of each transmission layer in the recent period. This statistical method adjusts channel state information, resolving the mismatch between channel state information and actual downlink PDSCH decoding capabilities. This allows for better feedback of the terminal's true decoding capabilities to the base station in the field, reducing the risk of large-scale bit errors or abnormal bit error rate fluctuations in the terminal. Furthermore, in step A2, the ratio of the maximum to minimum channel capacity of each transmission layer is calculated as the capacity ratio.

[0051] In step A2, the currently reported channel capacity values for each transmission layer are recorded. For transmission layers with more than two layers, the maximum and minimum channel capacity values in each transmission layer are calculated to obtain a capacity ratio. In step A3, the capacity ratio values calculated using the channel state information reference signal for a predetermined number n are averaged to obtain an average capacity ratio. If the predetermined number n is not reached, the initially generated feedback parameters are directly converted into channel state information and reported to the base station.

[0052] When performing CSI measurements, before the preset number n, due to the relatively small number of times, it is impossible to reflect whether the terminal signal is fluctuating or stable based on a simple number of times, and it cannot fully and accurately reflect the fluctuation of the current channel environment. Therefore, the channel state information formed by the initial feedback parameters is directly reported to the base station. After the preset number n, the number of times increases, and it can be reflected that the waveform is still stable, so the feedback parameters are adjusted.

[0053] Specifically, the preset number of times is dynamically adjusted according to the CSI feedback cycle.

[0054] In addition, if the CSI feedback cycle is relatively long, such as greater than 80ms, it means that the current environment is relatively stable and the preset number of times can be reduced. For example, if it is greater than 80ms, it is recommended to be within 5 times. If the CSI feedback cycle is relatively short, such as less than 80ms, the current environment may be unstable and the preset number n needs to be increased. For example, if it is less than 80ms, it is recommended to be around 10 times. The current n is only an ideal value for the current situation and can be configured and adjusted according to the actual situation during actual measurement.

[0055] In step A4, the average signal-to-noise ratio of the signal-to-noise ratios in m time slots within a predetermined time window before the time slot where the current channel state information reference signal is located is calculated.

[0056] Furthermore, the feedback parameters include a channel quality indicator (CQI);

[0057] In step A5, a channel correlation is determined based on the average capacity ratio, and a corresponding channel quality indicator is selected based on the channel correlation to replace the initial channel quality indicator.

[0058] Furthermore, the feedback parameters include a rank indication (RI);

[0059] In step A5, a penalty factor for the rank indication is selected according to the average capacity ratio and the average signal-to-noise ratio, and an updated rank indication is obtained based on the penalty factor for the rank indication, and the initial rank indication is replaced.

[0060] Furthermore, in step A5, the selection rule of the penalty factor of the rank indication is as follows:

[0061]

[0062] Among them, RI_punish_factor is the penalty factor of rank indication, snr is the average signal-to-noise ratio, and ratio is the average capacity ratio;

[0063] Among them, a <b<c,α<β<γ,th1> th2>th3.

[0064] The feedback parameters include a rank indicator and a channel quality indicator. In step A2, the maximum channel capacity-corresponding CQI algorithm may be used to obtain the initial RI and the corresponding CQI that currently need to be fed back.

[0065] In step A5, before selecting the RI penalty factor according to the selection rule, the penalty factors corresponding to different RIs are initially set to 1.

[0066] The average capacity ratio ratio is judged. If it is greater than ratio_th1, the channel correlation is judged to be strong correlation. If it is greater than ratio_th2 and less than ratio_th1, the channel correlation is judged to be medium correlation. The rest are judged to be low correlation.

[0067] The latest RI is obtained according to the selected RI penalty factor, and then the CQI value under the corresponding channel correlation is selected according to the determined channel correlation.

[0068] Compared with the existing technology, the present invention can utilize the characteristics of the UE downlink data channel to adaptively adjust the feedback CQI value and RI value, so that the downlink data channel PDSCH information scheduled by the base station is more in line with the actual decoding capability of the UE in the current channel environment, obtaining a smoother rate transmission, a better user experience, and less likely to drop the network.

[0069] See also Figure 2 The present invention provides a system for adjusting feedback parameters in channel state information, which is applied to a terminal and includes:

[0070] A channel capacity calculation module (1) is used to calculate the channel capacity based on the channel state information reference signal and obtain an initial feedback parameter based on the channel capacity;

[0071] A capacity ratio calculation module (2) is connected to the channel capacity calculation module (1) and is used to calculate the capacity ratio based on the channel capacity of each transmission layer;

[0072] A capacity ratio statistics module (3) is connected to the capacity ratio calculation module (2) and is used to average the capacity ratios calculated for a preset number of consecutive times to obtain an average capacity ratio;

[0073] A signal-to-noise ratio statistics module (4) is used to count the average signal-to-noise ratio in a predetermined time window before the time slot where the current channel state information reference signal is located;

[0074] The parameter updating module (5) is connected to the capacity ratio statistical module (3) and the signal-to-noise ratio statistical module (4) respectively, and is used to update the initial feedback parameters based on the average capacity ratio and the average signal-to-noise ratio, and then form updated channel state information based on the updated feedback parameters and report it to the base station.

[0075] The present invention reflects the volatility of terminal signals in the recent period by statistically analyzing the average channel capacity ratios and average signal-to-noise ratios of each transmission layer in the recent period. This statistical method is used to adjust the channel state information, solving the problem of incomplete matching between the channel state information and the actual downlink PDSCH decoding capability. This allows for better feedback of the terminal's more realistic decoding capability to the base station in the field, reducing the problem of large-scale bit errors or abnormal bit error rate fluctuations in the terminal.

[0076] Furthermore, the capacity ratio calculation module (2) calculates the ratio of the maximum value to the minimum value of the channel capacity of each transmission layer as the capacity ratio.

[0077] Record the currently reported channel capacity values for each transmission layer. For transmission layers with more than two layers, calculate the capacity ratio by taking the ratio of the maximum and minimum channel capacity values in each transmission layer. Average the capacity ratios calculated using the CSI reference signal for a preset number of times, n, to obtain the average capacity ratio. If the preset number of times, n, has not been reached, directly report the initial feedback parameters as CSI to the base station.

[0078] When performing CSI measurements, before the preset number n, due to the relatively small number of times, it is impossible to reflect whether the terminal signal is fluctuating or stable based on a simple number of times, and it cannot fully and accurately reflect the fluctuation of the current channel environment. Therefore, the channel state information formed by the initial feedback parameters is directly reported to the base station. After the preset number n, the number of times increases, and it can be reflected that the waveform is still stable, so the feedback parameters are adjusted.

[0079] Specifically, the preset number of times is dynamically adjusted according to the CSI feedback cycle.

[0080] In addition, if the CSI feedback cycle is relatively long, such as greater than 80ms, it means that the current environment is relatively stable and the preset number of times can be reduced. For example, if it is greater than 80ms, it is recommended to be within 5 times. If the CSI feedback cycle is relatively short, such as less than 80ms, the current environment may be unstable and the preset number n needs to be increased. For example, if it is less than 80ms, it is recommended to be around 10 times. The current n is only an ideal value for the current situation and can be configured and adjusted according to the actual situation during actual measurement.

[0081] Specifically, the average signal-to-noise ratio of the signal-to-noise ratios in m time slots within a predetermined time window before the time slot where the current channel state information reference signal is located is counted.

[0082] Furthermore, the feedback parameters include a channel quality indicator (CQI);

[0083] The parameter updating module (5) is used for determining the channel correlation based on the average capacity ratio, and selecting the corresponding channel quality indicator based on the channel correlation to replace the initial channel quality indicator.

[0084] Furthermore, the feedback parameters include a rank indication (RI);

[0085] The parameter updating module (5) is used to select a penalty factor of the rank indication according to the average capacity ratio and the average signal-to-noise ratio, obtain an updated rank indication based on the penalty factor of the rank indication, and replace the initial rank indication.

[0086] Furthermore, the parameter update module selects the penalty factor for the rank indication as follows:

[0087]

[0088] Among them, RI_punish_factor is the penalty factor of rank indication, snr is the average signal-to-noise ratio, and ratio is the average capacity ratio;

[0089] Among them, a <b<c,α<β<γ,th1> th2>th3.

[0090] Feedback parameters include rank indicator and channel quality indicator, and the algorithm of corresponding CQI of maximum channel capacity can be used to obtain the initial RI and corresponding CQI that need to be fed back.

[0091] Before selecting the RI penalty factor according to the selection rule, the penalty factors corresponding to different RIs are initially set to 1.

[0092] The average capacity ratio ratio is judged. If it is greater than ratio_th1, the channel correlation is judged to be strong correlation. If it is greater than ratio_th2 and less than ratio_th1, the channel correlation is judged to be medium correlation. The rest are judged to be low correlation.

[0093] The latest RI is obtained according to the selected RI penalty factor, and then the CQI value under the corresponding channel correlation is selected according to the determined channel correlation.

[0094] Compared with the existing technology, the present invention can utilize the characteristics of the UE downlink data channel to adaptively adjust the feedback CQI value and RI value, so that the downlink data channel PDSCH information scheduled by the base station is more in line with the actual decoding capability of the UE in the current channel environment, obtaining a smoother rate transmission, a better user experience, and less likely to drop the network.

[0095] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for adjusting feedback parameters in channel state information, characterized in that: include: Step A1, calculating channel capacity based on a channel state information reference signal, and obtaining an initial feedback parameter based on the channel capacity; Step A2, calculating a capacity ratio based on the channel capacity of each transmission layer; Step A3, averaging the capacity ratio values calculated for a preset number of consecutive times to obtain an average capacity ratio value; Step A4, calculating an average signal-to-noise ratio in a predetermined time window before the time slot where the current channel state information reference signal is located; Step A5: After updating the initial feedback parameters based on the average capacity ratio and the average signal-to-noise ratio, updated channel state information is formed based on the updated feedback parameters and reported to the base station.

2. The method for adjusting feedback parameters in channel state information according to claim 1, wherein: In the step A2, the ratio of the maximum value to the minimum value of the channel capacity of each transmission layer is calculated as the capacity ratio.

3. The method for adjusting feedback parameters in channel state information according to claim 1, wherein: The feedback parameter includes a channel quality indicator; In the step A5, a channel correlation is determined based on the average capacity ratio, and a corresponding channel quality indicator is selected based on the channel correlation to replace the initial channel quality indicator.

4. The method for adjusting feedback parameters in channel state information according to claim 1, wherein: The feedback parameter includes a rank indication; In step A5, a penalty factor for the rank indication is selected according to the average capacity ratio and the average signal-to-noise ratio, and an updated rank indication is obtained based on the penalty factor for the rank indication, and the updated rank indication is replaced with the initial rank indication.

5. The method for adjusting feedback parameters in channel state information according to claim 4, wherein: In step A5, the selection rule of the penalty factor of the rank indication is as follows: Wherein, RI_punish_factor is the penalty factor of the rank indication, snr is the average signal-to-noise ratio, and ratio is the average capacity ratio; Among them, a <b<c,α<β<γ,th1> th2>th3.

6. A system for adjusting feedback parameters in channel state information, applied to a terminal, characterized in that: include: a channel capacity calculation module, configured to calculate the channel capacity based on the channel state information reference signal, and obtain an initial feedback parameter based on the channel capacity; a capacity ratio calculation module, connected to the channel capacity calculation module, configured to calculate a capacity ratio based on the channel capacity of each transmission layer; a capacity ratio statistics module, connected to the capacity ratio calculation module, configured to average the capacity ratios calculated for a preset number of consecutive times to obtain an average capacity ratio; A signal-to-noise ratio statistics module, configured to calculate an average signal-to-noise ratio in a predetermined time window before a time slot where the current channel state information reference signal is located; A parameter updating module is connected to the capacity ratio statistics module and the signal-to-noise ratio statistics module, respectively, and is used to update the initial feedback parameters based on the average capacity ratio and the average signal-to-noise ratio, and then form the updated channel state information based on the updated feedback parameters and report it to the base station.

7. The system for adjusting feedback parameters in channel state information according to claim 6, wherein: The capacity ratio calculation module calculates the ratio of the maximum value to the minimum value of the channel capacity of each transmission layer as the capacity ratio.

8. The system for adjusting feedback parameters in channel state information according to claim 6, wherein: The feedback parameter includes a channel quality indicator; The parameter updating module is configured to determine a channel correlation based on the average capacity ratio, and select a corresponding channel quality indicator based on the channel correlation to replace an initial channel quality indicator.

9. The system for adjusting feedback parameters in channel state information according to claim 6, wherein: The feedback parameter includes a rank indication; The parameter updating module is configured to select a penalty factor for the rank indication according to the average capacity ratio and the average signal-to-noise ratio, obtain an updated rank indication based on the penalty factor for the rank indication, and replace the initial rank indication.

10. The system for adjusting feedback parameters in channel state information according to claim 9, wherein: The parameter updating module selects the penalty factor for the rank indication as follows: Wherein, RI_punish_factor is the penalty factor of the rank indication, snr is the average signal-to-noise ratio, and ratio is the average capacity ratio; Among them, a <b<c,α<β<γ,th1> th2>th3.

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