A method and system for receiving and processing SRS in a distributed networking

Abstract

The application belongs to the technical field of wireless communication, and discloses a receiving and processing method and system of SRS in a distributed networking. A protocol stack configures terminal SRS sending parameters, independently configures first SRS receiving parameters facing a baseband processing unit and second SRS receiving parameters facing a radio frequency unit. The radio frequency unit completes uplink SRS signal preprocessing according to the second receiving parameters and transmits to the baseband processing unit, and the baseband processing unit completes SRS detection of multi-radio frequency unit backhaul signals through the first receiving parameters. The protocol stack dynamically determines SRS receiving resources in combination with channel state parameters between the terminal and the radio frequency unit. The application independently configures the first SRS receiving parameters and the second SRS receiving parameters, uses a guard symbol to offset signal time delay distortion of long-distance transmission, and suppresses inter-symbol interference. Meanwhile, according to SRS time-frequency resource intervals, uplink channel scheduling conflicts are avoided, time-frequency interference is reduced, and SRS detection accuracy is ensured.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a method and system for receiving and processing SRS in a distributed network. Background Technology

[0002] Distributed networking adopts a centralized baseband processing unit (BBU) and distributed radio frequency (RU) deployment architecture. It relies on the collaborative transceiver capabilities of multiple radio frequency heads to achieve wide-area coverage and reduce networking costs. It is now widely used in low-frequency and millimeter-wave FR2 band wireless communication systems. Millimeter waves, due to their large bandwidth advantage, are often used in high-throughput scenarios such as ports, wind power, and tunnels. In these scenarios, the distance between sites generally exceeds 300 meters, and the terminal mobility speed can reach more than 15m / s, which places stringent requirements on long-distance networking capabilities.

[0003] Under the existing 3GPP protocol, the SRS (Sounding Reference Signal) adopts a combing and cyclic shift multiplexing design. Due to the influence of ISI (Inter-Symbol Interference) caused by CP-OFDM (Cyclic Prefix; Orthogonal Frequency Division Multiplexing) and the limitation of large spacing between millimeter-wave subcarriers, the theoretical networking distance of FR2 millimeter-wave is only 80 to 1200 meters under different SRS configurations, which is far lower than that of FR1 low-frequency band, making it difficult to meet the requirements of large-spacing deployment.

[0004] There are two main ways to improve network distance: one is to use multi-slot multi-comb frequency hopping to transmit SRS, relying on the joint operation of multiple SRS resources to extend the measurement distance. However, this approach requires a lot of additional time and frequency resources, resulting in high spectrum resource overhead. The other approach uses a receiver distance ambiguity compensation algorithm to optimize SRS delay detection. This approach only optimizes the arrival time calculation and cannot eliminate the interference problem caused by SRS cross-symbols from multiple terminals. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for receiving and processing SRS in a distributed network, and to solve problems such as inter-symbol interference, limited network distance, and channel interference in SRS.

[0006] To address the aforementioned technical problems, this invention provides a method for receiving and processing SRS in a distributed network, comprising: The protocol stack configures the SRS transmission parameters for the terminal and independently configures the first SRS reception parameters of the baseband processing unit and the second SRS reception parameters of the radio frequency unit. The radio frequency unit preprocesses the received uplink SRS signal according to the second SRS receiving parameters and sends it to the baseband processing unit. The baseband processing unit performs SRS detection on the preprocessed SRS signals returned by each radio frequency unit according to the first SRS receiving parameters. When scheduling the first SRS reception parameters and the second SRS reception parameters, the protocol stack dynamically determines the SRS reception resources based on at least one channel state parameter between the terminal and the radio frequency unit.

[0007] Furthermore, the SRS receiving resource contains K+n+m consecutive OFDM symbols in the time domain, where one symbol is an SRS symbol, n is the number of SRS front protection symbols, and m is the number of SRS rear protection symbols, where n is an integer greater than or equal to 0 and m is an integer greater than or equal to 1. The front protection symbol and the rear protection symbol together constitute the SRS receive resource protection band; Within the time-frequency resource range corresponding to the SRS receive resource protection band, the protocol stack does not schedule any other uplink channels and uplink signals of any terminal; when the base station performs reception processing, it extracts all the time-frequency resources corresponding to the SRS receive resource protection band and performs reception and demodulation operations uniformly.

[0008] Furthermore, the first SRS receiving parameters include a first terminal ID, a baseband processing unit ID, a first radio frequency unit ID, and a first SRS resource location; the first SRS resource location corresponds to the set of frequency domain RBs and the set of time domain continuous OFDM symbols occupied by the terminal. The first SRS resource location includes the first SRS frequency domain resource location, the first SRS time domain resource location, and the first SRS sequence parameters; The first SRS frequency domain resource location includes the starting resource block (RB), the number of persistent resource blocks, and the SRS resource unit (RE) offset; The first SRS time-domain resource location includes the SRS start symbol and the SRS persistence symbol; The first SRS sequence parameters include sequence group, sequence number, and sequence ID, which are used by the baseband processing unit to generate terminal-level SRS reference sequences; The first SRS receiving parameter is configured independently of the SRS parameters sent by the terminal.

[0009] Furthermore, the second SRS receiving parameters include the second terminal ID, the second radio frequency unit ID, the second SRS resource location, the SRS radio frequency unit processing configuration parameters, and the SRS backhaul forward transmission length. The second SRS resource location includes a second SRS frequency domain resource location and a second SRS time domain resource location; The second SRS frequency domain resource location includes the starting resource block RB, the number of persistent resource blocks, and the SRS resource unit RE offset; The second SRS time-domain resource location includes both an SRS start symbol and an SRS persistence symbol; The second SRS receiving parameters are simultaneously sent to the baseband processing unit, which adaptively matches the corresponding SRS receiving processing mode according to the configuration of the second SRS receiving parameters.

[0010] Furthermore, the SRS radio frequency unit processing configuration parameters include SRS transmission type indication, CP removal indication, FFT indication, and downsampling indication; The radio frequency unit performs preprocessing according to the SRS radio frequency unit processing configuration parameters in any of the following ways: When the SRS transmission type is a time-domain signal, no CP removal processing and FFT processing are performed; only downsampling processing is performed. When the SRS transmission type is a time-domain signal, CP removal processing is performed, FFT processing is not performed, and only downsampling processing is performed. When the SRS transmission type is a frequency domain signal, CP removal processing, FFT processing, and downsampling processing are performed.

[0011] Furthermore, the channel state parameters include the distance difference between the terminal and each radio frequency unit, the received power, the moving speed, and the location information; The protocol stack determines whether the terminal is in long-range mode or non-long-range mode based on the channel state parameters, and determines the number of front protection symbols and rear protection symbols based on the decision result.

[0012] Furthermore, the protocol stack determines whether the terminal is in long-distance mode or non-long-distance mode, specifically including: Assuming the radio frequency unit is i, the distance between the terminal and the radio frequency unit is d(i), and the power value measured by the radio frequency unit is a(i), the power value includes at least one of RSRP, SNR, SINR or RSSI; Select radio frequency units whose power value a(i) is greater than or equal to the first power threshold to form a set of candidate radio frequency units; Calculate the relative distance d(i,j) = |d(i) - d(j)| from any two radio frequency units i and j in the candidate set to the terminal, and take the maximum value max(d(i,j)) in the set. If max(d(i,j)) is less than the lowest order distance threshold, the terminal is determined to be in non-long-range mode, and the number of processing symbols of SRS receiving resources is configured to 1 symbol, i.e. n=0, m=0; If max(d(i,j)) is located within the interval formed by any two adjacent distance thresholds, then the terminal is determined to be in long-range mode. Based on the distance threshold interval into which max(d(i,j)) falls, the number of processing symbols for SRS receiving resources is configured to be K+n+m symbols, where n≥0 and m≥1.

[0013] Furthermore, when the terminal is closest to one of the radio units in the set of candidate radio units, and the power value of the radio unit is not lower than the second power threshold, regardless of the value of the maximum value max(d(i,j)) in the set, the number of front protection symbols of the terminal is configured as n=0 and the number of rear protection symbols is configured as m≥1, that is, the number of symbols processed by the SRS receiving resources is K+m symbols.

[0014] Furthermore, for each terminal in the current time slot, the protocol stack merges the two ranges according to the time domain symbol range and frequency domain resource range corresponding to the SRS receiving resources, and the transmission time domain symbol range and frequency domain resource range corresponding to the SRS transmission parameters configured by the protocol stack for the terminal, to obtain the SRS resource set occupied by a single terminal. The protocol stack performs a union operation on the SRS resource sets corresponding to all terminals in the same time slot to generate the total SRS resource set. The protocol stack avoids the time-frequency resources corresponding to the total SRS occupied resource set and schedules the remaining uplink channels on the remaining idle time-frequency resources; The protocol stack schedules other uplink channels on time-frequency resources outside the time-frequency range corresponding to the total SRS occupied resource set.

[0015] On the other hand, the present invention provides a distributed network SRS receiving and processing system, including a network module and a terminal module connected to each other. The network module includes multiple radio frequency units and wireless access units. The wireless access unit includes a protocol stack and a baseband processing unit. The protocol stack is connected to the baseband processing unit, and the baseband processing unit is connected to each radio frequency unit through a fronthaul interface. The protocol stack independently configures the first SRS receiving parameters and the second SRS receiving parameters, and sends the first SRS receiving parameters and the second SRS receiving parameters to the baseband processing unit. The baseband processing unit sends the received second SRS receiving parameters to the corresponding radio frequency unit; The radio frequency unit preprocesses the received uplink SRS signal according to the second SRS receiving parameters, and sends the preprocessed signal back to the baseband processing unit. The baseband processing unit performs SRS detection on the preprocessed signals returned by each radio frequency unit based on the first SRS receiving parameters.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention independently configures the first SRS receiving parameters of the baseband processing unit and the second SRS receiving parameters of the radio frequency unit through the protocol stack. It distinguishes between long-distance and non-long-distance working modes based on the distance and power parameters between the terminal and each radio frequency unit, and adaptively configures the SRS protection symbols before and after transmission. The protection symbols are used to cancel the signal delay distortion caused by long-distance transmission, effectively suppressing the inter-symbol interference of SRS in large-spacing networking scenarios. At the same time, it integrates the SRS transmission resources and reception resources to define a complete occupied interval, avoids scheduling the uplink channel for SRS occupied resources, reduces time-frequency interference, and ensures the accuracy of SRS detection. Attached Figure Description

[0017] Figure 1 This is a flowchart of an SRS receiving and processing method in a distributed network according to an embodiment of the present invention; Figure 2 This is a schematic diagram of transmission resources in a dual-terminal scheduling scenario according to one embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the SRS receiving system in a distributed network according to an embodiment of the present invention. Detailed Implementation

[0018] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this application.

[0019] The following will describe in more detail a method and system for receiving and processing SRS in a distributed network according to the present invention, with reference to the schematic diagrams, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving the advantageous effects of the invention. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0020] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0021] Example 1 like Figure 1 As shown in the figure, this invention proposes a method for receiving and processing SRS in a distributed network. The method utilizes a protocol stack, a baseband processing unit, and multiple radio frequency units to coordinate uplink SRS scheduling and demodulation. This method is suitable for millimeter-wave, large-pitch distributed networking scenarios such as ports, offshore wind farms, oil and gas fields, smart highways, and tunnels. The network spacing can reach over 300 meters, meeting the high-speed mobile communication requirements of terminals with a moving speed ≥15m / s. It overcomes the shortcomings of short OFDM symbol duration in the FR2 millimeter-wave band, limited coverage distance in conventional SRS networks, and radio frequency unit delays exceeding CP interference.

[0022] Specifically, the method includes the following steps: Step 1: The protocol stack configures the SRS transmission parameters for the terminal and independently configures the first SRS reception parameters for the baseband processing unit and the second SRS reception parameters for the radio frequency unit. On one hand, the protocol stack configures the SRS transmission parameters for the terminal, specifying the time-frequency resources (time-domain and frequency-domain resources, collectively referred to as time-frequency resources), modulation method, and transmission timing occupied by the terminal's actual air interface transmission of the SRS signal. On the other hand, the protocol stack independently configures the first and second SRS reception parameters, allowing the reception and demodulation configurations of the baseband processing unit and the radio frequency unit to be freely set independent of the terminal's original transmission parameters. This overcomes the traditional limitation that transmission and reception parameters must remain consistent and allows for flexible adaptation of reception processing rules based on network coverage distance.

[0023] When scheduling the first SRS reception parameters and the second SRS reception parameters, the protocol stack dynamically determines the SRS reception resources based on at least one channel state parameter between the terminal and the radio frequency unit.

[0024] Step 2: The radio frequency unit preprocesses the received uplink SRS signal according to the second SRS receiving parameters and sends it to the baseband processing unit. The purpose of the radio frequency unit preprocessing is to convert the analog radio frequency signal into a digital signal format suitable for fronthaul transmission, and at the same time, to compress the fronthaul bandwidth usage through operations such as downsampling.

[0025] Step 3: The baseband processing unit (BBU) performs SRS detection on the preprocessed SRS signals returned by each radio frequency unit (RU) according to the first SRS reception parameters. After receiving the preprocessed SRS signals returned by each RU, the BBU performs SRS detection according to the first SRS reception parameters. By aggregating signals from multiple RUs for joint processing, the BBU can fully utilize the spatial diversity gain of the distributed antenna, thereby improving the detection accuracy and coverage of SRS.

[0026] In this embodiment, the first SRS receiving parameters include the first terminal ID, the baseband processing unit ID, the first radio frequency unit ID, and the first SRS resource location.

[0027] The first terminal ID is used to identify the target terminal sending SRS, the baseband processing unit ID is used to indicate which baseband processing unit (BBU) is responsible for processing the SRS of this terminal, and the first radio frequency unit ID is used to identify the set of radio frequency units (RUs) participating in the SRS reception of this terminal. The above three types of identification information together constitute the information of the baseband processing unit (BBU) SRS detection task, enabling the baseband processing unit (BBU) to associate the correct SRS signal from the correct radio frequency unit (RU) with the correct terminal, supporting accurate parsing in multi-terminal concurrent SRS detection scenarios.

[0028] The first SRS resource location corresponds to the frequency domain RB set and time domain continuous OFDM symbol set occupied by the terminal, which intuitively defines the entire range of time and frequency resources required for terminal reception and demodulation.

[0029] Furthermore, the first SRS resource location includes the first SRS frequency domain resource location, the first SRS time domain resource location, and the first SRS sequence parameters.

[0030] The first SRS frequency domain resource location includes the starting resource block RB, the number of continuous resource blocks, and the SRS resource unit RE offset. The start and end positions of the SRS signal in the frequency domain are determined by the starting RB and the number of continuous resource blocks. The RE offset is further refined to the subcarrier granularity, so that the baseband processing unit BBU can accurately extract the target frequency domain resources during SRS detection.

[0031] The first SRS time-domain resource location includes an SRS start symbol and an SRS persistence symbol, which are used to define the starting position of the SRS symbol and the number of symbols occupied, so that the baseband processing unit (BBU) can accurately locate the effective range of the SRS signal in the time domain.

[0032] The first SRS sequence parameters include sequence group u, sequence number v, and sequence ID, which are used by the baseband processing unit to generate a terminal-level SRS reference sequence to facilitate subsequent correlation detection and channel estimation.

[0033] It is worth noting that the first SRS receiving parameter is configured independently of the SRS parameters sent by the terminal, which allows the baseband processing unit (BBU) to flexibly adjust the receiving parameters (e.g., modify the receiving window range without notifying the terminal) without reconfiguring the terminal, reducing signaling overhead and providing flexibility for the adaptive receiving optimization of the baseband processing unit (BBU).

[0034] In this embodiment, the second SRS receiving parameters include the second terminal ID, the second radio frequency unit ID, the second SRS resource location, the SRS radio frequency unit processing configuration parameters, and the length of the forward transmission data during SRS backhaul.

[0035] The second terminal ID is used to identify the set of terminals corresponding to the SRS transmission, the second radio frequency unit ID identifies the target radio frequency unit RU that needs to perform preprocessing tasks, and the second SRS resource location defines the range of time and frequency resources that the radio frequency unit RU needs to extract and preprocess.

[0036] The second SRS resource location includes a second SRS frequency domain resource location and a second SRS time domain resource location. The second SRS frequency domain resource location includes the start resource block (RB), the number of persistent resource blocks, and the SRS resource element (RE) offset. The second SRS time domain resource location includes both the SRS start symbol and the SRS persistent symbol. The parameter structure of the second SRS frequency domain resource location and the second SRS time domain resource location is consistent with the first SRS receiving parameters, but the values ​​within the parameters can take different specific values, reflecting the independence of the resource window definition between the baseband processing unit (BBU) and the radio frequency unit (RU). The length of the forward transmission data during SRS return is used to represent the length of SRS data transmitted on the forward transmission link from the radio frequency unit (RU) to the baseband processing unit (BBU).

[0037] For example, suppose there are 3 terminals, and the protocol stack configures the first SRS receive parameters for the three terminals as follows: The terminal with the first terminal ID 1 has the following configuration for the first SRS frequency domain resource location: the starting resource block RB is 12, the number of continuous resource blocks is 12, and the SRS resource unit RE offset is 0; the corresponding first SRS time domain resource location is configured as follows: the SRS starting symbol is 12, and the SRS continuous symbol is 1.

[0038] The first terminal with terminal ID 2 has the following configuration for the first SRS frequency domain resource location: the starting resource block RB is 12, the number of continuous resource blocks is 12, and the SRS resource unit RE offset is 4; the corresponding first SRS time domain resource location configuration is: the SRS starting symbol is 11, and the SRS continuous symbol is 3.

[0039] The terminal with terminal ID 3 has the following configuration for the first SRS frequency domain resource location: the starting resource block RB is 12, the number of continuous resource blocks is 12, and the SRS resource unit RE offset is 1; the corresponding first SRS time domain resource location is configured as follows: the SRS starting symbol is 10, and the SRS continuous symbol is 1.

[0040] The protocol stack combines the first SRS reception parameters corresponding to each terminal with the terminal's working mode to uniformly schedule and distribute the second SRS reception parameters, as follows: The terminal set corresponding to the second terminal ID1 is {first terminal ID1=1, second terminal ID2=2}. Therefore, the second SRS frequency domain resource location is defined as follows: the starting resource block RB is 12, the number of persistent resource blocks is 12, and the SRS resource unit RE bias is 0. The second SRS time domain resource location is defined as: the SRS start symbol is 11, and the SRS persistent symbol is 3. The corresponding radio frequency unit RU performs unified preprocessing on the SRS received signals of the first terminal ID1 and the first terminal ID2, and transmits the processed signals back to the baseband processing unit BBU through the fronthaul interface. After parsing the second SRS received parameters, the baseband processing unit BBU identifies the SRS signals corresponding to the first terminal ID1 and the first terminal ID2 in this data set. Subsequently, based on the first SRS received parameters of each of the two terminals, subsequent processing is performed sequentially for each terminal.

[0041] The terminal set corresponding to the second terminal ID2 is {first terminal ID3=3}. Therefore, the second SRS frequency domain resource location is defined as follows: starting resource block RB is 12, the number of persistent resource blocks is 12, and the SRS resource element RE bias is 1. The second SRS time domain resource location is defined as: SRS start symbol is 10, and SRS persistent symbol is 1. The corresponding radio frequency unit RU performs preprocessing on the uplink SRS signal of the first terminal ID3 and transmits the signal back to the baseband processing unit via the fronthaul interface. The baseband processing unit, by parsing the second SRS reception parameters, determines that this set of data corresponds only to the first terminal ID3, and then completes the SRS reception processing of this terminal according to the matching first SRS reception parameters.

[0042] Furthermore, it should be noted that the second SRS reception parameters are simultaneously sent to the baseband processing unit (BBU). The BBU adaptively matches the corresponding SRS reception processing mode based on the configuration of the second SRS reception parameters. Since different radio frequency units (RUs) may employ different preprocessing modes (e.g., time-domain transmission or frequency-domain transmission), the BBU automatically selects a post-processing procedure compatible with the RU's preprocessing results by parsing information such as the SRS transmission type in the second SRS reception parameters. This avoids the complex operation of manually configuring the BBU's processing mode and improves the system's adaptability.

[0043] Furthermore, the SRS radio frequency unit processing configuration parameters include SRS transmission type indication, de-CP indication, FFT indication, and downsampling indication. The radio frequency unit performs preprocessing according to the SRS radio frequency unit processing configuration parameters in any of the following ways.

[0044] The first preprocessing method: When the SRS transmission type is a time-domain signal, no CP removal or FFT processing is performed on each SRS symbol; only downsampling processing is performed (in addition, during processing, the SRS received signal is frequency-shifted according to the second SRS frequency domain resource location to shift the SRS frequency domain signal to zero frequency). This method is suitable for scenarios that require compression of the fronthaul bandwidth but want to retain the complete time-domain waveform for flexible processing by the baseband processing unit (BBU). The radio frequency unit (RU) only downsamples the time-domain sampled data and transmits it back directly. After receiving it, the baseband processing unit (BBU) can complete the correlation detection of the SRS sequence in the time domain, thus minimizing the processing complexity requirements for the radio frequency unit (RU).

[0045] When using the first preprocessing method, the RF unit retains the cyclic prefix of the original signal within the continuous SRS symbol interval corresponding to [SRS start symbol, SRS start symbol + continuous symbol], without performing CP removal operation, and without performing FFT (Fast Fourier Transform) operation for time-domain to frequency-domain conversion. The RF unit performs downsampling processing on the SRS resources corresponding to the complete K+n+m OFDM symbols, and the downsampling factor can be an integer power of 2.

[0046] Subsequently, the RF unit transmits the downsampled and compressed time-domain signal to the baseband processing unit via the fronthaul interface. The fronthaul data length is equal to the original SRS symbol length divided by the downsampling factor (the original SRS symbol length is expressed as the length of K+n+m OFDM symbols (including the CP length on each symbol)). After receiving the time-domain signal, the baseband processing unit generates an SRS reference sequence based on the downsampling factor and the number of SRS-occupied symbols, and performs SRS detection.

[0047] Specifically, the SRS detection includes channel estimation, RSRP (Reference Signal Received Power) measurement, RSSI (Received Signal Strength Indicator) measurement, TA (Timing Advance) measurement, and SINR (Signal to Interference plus Noise Ratio) measurement.

[0048] The second preprocessing method: When the SRS transmission type is a time-domain signal, CP removal is performed on each SRS symbol, but FFT processing is not performed; only downsampling processing is performed. Compared to the first method, the RF unit (RU) removes the cyclic prefix (CP) before transmission, which can further reduce the amount of data transmitted back. After receiving the CP-removed time-domain data, the baseband processing unit (BBU) completes subsequent detection based on the known SRS time-frequency resource locations. This method is suitable for scenarios where signal integrity still meets detection requirements after CP removal.

[0049] When the second preprocessing method is used, the RF unit performs CP removal processing on the received signal within the continuous SRS symbol interval corresponding to [SRS start symbol, SRS start symbol + continuous symbol]. The RF unit does not perform FFT operations to convert the time domain to the frequency domain on the SRS symbols. The RF unit performs downsampling on all SRS resources corresponding to K+n+m OFDM symbols, and the downsampling factor is selected as an integer power of 2.

[0050] Subsequently, the RF unit sends the downsampled and compressed time-domain signal to the baseband processing unit via the fronthaul interface. The fronthaul data length is equal to the original SRS symbol length divided by the downsampling factor (the original SRS symbol length is expressed as the length of K+n+m OFDM symbols (excluding the CP length on each symbol)). After receiving the time-domain signal, the baseband processing unit combines the downsampling factor and the number of SRS symbols to generate an SRS reference sequence and performs SRS detection.

[0051] The third preprocessing method: When the SRS transmission type is a frequency domain signal, CP removal, FFT processing, and downsampling are performed on each SRS symbol. The RF unit RU performs CP removal and FFT transformation on the OFDM symbols corresponding to the SRS received resources, converting the signal into frequency domain subcarrier data before downsampling and transmission. The frequency domain data can be directly used for frequency domain channel estimation by the baseband processing unit (BBU), resulting in a shorter processing link, suitable for scenarios requiring optimization of the computational complexity of the baseband processing unit (BBU).

[0052] When the third preprocessing method is used, the RF unit performs CP removal processing on the received signal within the continuous SRS symbol interval corresponding to [SRS start symbol, SRS start symbol + continuous symbol]. The RF unit performs FFT operations on each SRS symbol to complete the conversion from time-domain signal to frequency-domain signal. The RF unit performs downsampling on all SRS resources corresponding to K+n+m OFDM symbols, with the downsampling factor selected as an integer power of 2.

[0053] Subsequently, the RF unit transmits the compressed frequency domain signal to the baseband processing unit via the fronthaul interface. The fronthaul data length is equal to the SRS data length after removing the CP (Constant Propagation) divided by the downsampling factor. After receiving the frequency domain SRS signal, the baseband processing unit first transforms the frequency domain data into a time domain signal based on the downsampling factor and the number of SRS symbols, then generates an SRS reference sequence and performs SRS detection.

[0054] The three preprocessing methods can be flexibly selected through configuration parameters, enabling the system to be comprehensively optimized based on multiple factors such as fronthaul bandwidth constraints, RF unit (RU) processing capabilities, and baseband processing unit (BBU) computing resources, making it highly adaptable.

[0055] In this embodiment, the SRS receiving resource comprises K+n+m consecutive OFDM symbols in the time domain, where one symbol is an SRS symbol, n symbols are SRS front protection symbols, and m symbols are SRS rear protection symbols, where n is an integer greater than or equal to 0, and m is an integer greater than or equal to 1. The front protection symbols and the rear protection symbols together constitute the SRS receiving resource protection band.

[0056] The minimum value of the rear guard symbol m is set to 1 instead of 0 because the symbols following the SRS symbol (i.e., the CP part of the next symbol) are most susceptible to delay spread. In any scenario, at least one rear guard symbol is required to absorb the time-domain tail of SRS energy. The front guard symbol n can be set to 0 in close-range scenarios, that is, protection is only set after the SRS symbol, thereby maintaining the reliability of SRS reception while conserving time and frequency resources as much as possible.

[0057] Within the time-frequency resource range corresponding to the SRS receive resource protection band, the protocol stack does not schedule any other uplink channels and uplink signals of any terminal. The unused SRS receive resource protection band can buffer the signal transmission delay of different radio frequency units, reducing interference sources from the source of resource scheduling. Furthermore, when the base station performs reception processing, it extracts all the time-frequency resources corresponding to the SRS receive resource protection band and performs unified reception and demodulation operations, rather than only extracting the SRS symbols themselves. Therefore, when there is delay spread in the SRS signal, the SRS energy has actually diffused into the SRS receive resource protection band. Including the SRS receive resource protection band in the reception processing range is equivalent to converging all effective SRS energy, which helps improve the SRS reception signal-to-noise ratio and detection accuracy.

[0058] In this embodiment, the channel state parameters include the distance difference between the terminal and each radio frequency unit (RU), the received power, the moving speed, and the location information. The protocol stack determines whether the terminal is in long-range mode or non-long-range mode based on these channel state parameters, and determines the number of forward and backward protection symbols based on the decision. Long-range mode is suitable for scenarios where the distance difference between the terminal and different RUs is large. In this case, the time delay difference of the SRS signal arriving at each RU is large, and the time domain spread is significant, requiring the allocation of more protection symbols. Non-long-range mode corresponds to scenarios where the distance between the terminal and each RU is relatively uniform, the time domain spread is limited, and protection symbols can be reduced or even eliminated, saving time and frequency resources. By introducing a channel state-aware dynamic decision mechanism, the system can achieve reliable SRS reception with the lowest resource cost in different scenarios.

[0059] Furthermore, the protocol stack determines whether the terminal is in long-distance mode or non-long-distance mode, and the specific steps are as follows: Assuming the radio frequency unit is i, the distance between the terminal and the radio frequency unit is d(i), and the power value measured by the radio frequency unit is a(i), the power value includes at least one of RSRP, SNR, SINR or RSSI.

[0060] The first step is to select radio frequency units (RF units) whose power value a(i) is greater than or equal to the first power threshold, forming a set of candidate RF units. The purpose of setting the power threshold is to exclude RF units (RUs) with poor signal quality and limited contribution to the terminal's SRS reception, so as to avoid them introducing false distance difference estimates and affecting the accuracy of the decision.

[0061] The second step is to calculate the relative distance d(i,j) = |d(i)-d(j)| from any two radio frequency units i and j in the candidate set to the terminal, and take the maximum value max(d(i,j)) in the set. Third, if the maximum value max(d(i,j)) is less than the lowest order distance threshold, the terminal is determined to be in non-long-distance mode, and the number of processing symbols for SRS receiving resources is configured to 1 symbol, i.e. n=0, m=0. This means that no additional protection symbols are needed, maximizing resource utilization efficiency.

[0062] If the maximum value max(d(i,j)) is located within the interval formed by any two adjacent distance thresholds, then the terminal is determined to be in long-range mode. Based on the distance threshold interval into which the maximum value max(d(i,j)) falls, the number of processed symbols of the SRS receiving resources is configured to be K+n+m symbols, where n≥0 and m≥1.

[0063] For example, as shown in Table 1 below, when the maximum value max(d(i,j)) falls within the range formed by threshold X=1 and threshold Y=2, then the front protection symbol n=1 and the rear protection symbol m=1 are configured, and the number of SRS receiving resources processed is K+1+1.

[0064] When the maximum value max(d(i,j)) falls within the range formed by threshold X=2 and threshold Y=3, then the front protection symbol n=2 and the rear protection symbol m=2 are configured, and the number of SRS receiving resources to be processed is K+2+2.

[0065] When the maximum value max(d(i,j)) falls within the range formed by threshold X=3 and threshold Y=4, then the front protection symbol n=3 and the rear protection symbol m=3 are configured, and the number of SRS receiving resources to process symbols is K+3+3.

[0066] Table 1

[0067] As can be seen from the above, the higher the distance to the threshold interval, the more protection symbols are allocated.

[0068] The aforementioned tiered decision mechanism discretizes the continuous distance difference space into a finite number of levels, balancing configuration flexibility with implementation complexity. The protocol stack can flexibly set the specific values ​​of each distance threshold according to the actual deployment scenario. Furthermore, when the terminal is closest to one of the radio units in the candidate radio unit set, and the power value of the radio unit is not lower than the second power threshold, regardless of the value of the maximum value max(d(i,j)) in the set, the number of front protection symbols of the terminal is configured as n=0, and the number of rear protection symbols is configured as m≥1, that is, the number of symbols processed for SRS reception resources is K+m symbols. That is, when there is a near-end radio unit RU with extremely high power, this radio unit RU contributes significantly more to the terminal's SRS reception than other radio unit RUs. The baseband processing unit BBU can mainly rely on the SRS reception result of the near-end radio unit RU to complete the detection task, and the time-domain lead of the SRS signal at the near-end radio unit RU (i.e., front overflow) is extremely small, and the front protection symbols can be safely cancelled (i.e., n=0); however, since the SRS energy may still extend backward, the rear protection symbols m≥1 still need to be retained, thereby achieving further resource saving under specific topology conditions, while maintaining the reliability of SRS reception.

[0069] In this embodiment, the protocol stack merges the two ranges for each terminal in the current time slot according to the time domain symbol range and frequency domain resource range corresponding to the SRS receiving resources, and the transmission time domain symbol range and frequency domain resource range corresponding to the SRS transmission parameters configured by the protocol stack for the terminal, to obtain the SRS resource set occupied by a single terminal.

[0070] The protocol stack performs a union operation on the SRS resource sets corresponding to all terminals within the same time slot to generate a total SRS resource set. The protocol stack then avoids the time-frequency resources corresponding to this total SRS resource set and schedules the remaining uplink channels on the remaining idle time-frequency resources. The protocol stack also schedules other uplink channels on time-frequency resources outside the time-frequency range corresponding to the total SRS resource set.

[0071] Specifically, the SRS resource allocation set consists of the frequency domain resource block (RB) range where the SRS symbol is located and the time domain symbol range including the preceding and following guard symbols, representing the complete occupation of system time-frequency resources during the terminal's SRS reception process. The protocol stack merges the SRS resource allocation sets of all terminals within the same time slot to obtain the total SRS resource allocation set, which covers the time-frequency resources required for all SRS reception activities within the current time slot. The protocol stack schedules other uplink channels (such as PUSCH, PUCCH, etc.) on idle time-frequency resources outside the total SRS resource allocation set, achieving complete orthogonal isolation between SRS reception resources and other uplink channels in the time-frequency domain, eliminating co-channel interference during SRS reception, ensuring SRS detection performance, and simultaneously enabling full reuse of non-SRS time-frequency resources, thus improving the overall system spectral efficiency.

[0072] The SRS resource allocation for each terminal in the current time slot is represented by the following format: {Time Slot ID}{Terminal ID}{Start Resource Block RB + (0 ~ Persistent Resource Block RB)}{Start Processing Symbol + (0 ~ Persistent Processing Symbol)}, where the frequency domain boundary is defined by the number of start resource blocks RB and persistent resource blocks, and the time domain boundary is defined by the number of SRS start processing symbols and persistent processing symbols. The aforementioned frequency and time domain ranges correspond one-to-one with the SRS frequency domain resource positions and SRS time domain resource positions recorded in the first SRS reception parameters. This format allows for precise identification of the frequency domain resource blocks RB and time domain OFDM symbol positions occupied by each terminal's SRS.

[0073] The union of the SRS processing resources of all terminals in the current time slot constitutes the total SRS occupied resource set of the current time slot. The total SRS occupied resource set defines the resource range within the time slot from which other channels cannot be scheduled.

[0074] Taking a single-terminal scheduling scenario as an example, the overall frequency domain RB range to be scheduled in the current time slot is 0 to N. RB-1, the range of time-domain symbols to be scheduled is 0 to Nsym-1. When only the first terminal exists, the SRS frequency domain resources of the first terminal start from NRB1 and continuously occupy NRB. 12 One RB, with time-domain resources starting from Nsym1 and continuously occupying Nsym. 12 The symbols are RB and NRB, where RB represents a resource block and NRB represents the total number of resource blocks, 0 to N. RB -1 represents the range of all available frequency domain resource blocks in the current time slot, Nsym represents the total number of OFDM symbols in a single time slot, and 0 to Nsym-1 represent the range of all available time domain symbols in the current time slot. Nsym1 represents the starting OFDM symbol number of the first terminal SRS, Nsym 12 This indicates the number of OFDM symbols continuously occupied by the first terminal SRS.

[0075] In this scenario, two types of non-SRS scheduling resources are obtained that can be used for other channel scheduling: the first type is time-domain resources {0~Nsym-1} and frequency-domain resources {0~NRB1-1, NRB1+NRB}. 12 ~N RB -1}; The second category is SRS frequency domain resources {NRB1+(0~NRB)}; 12 -1)} and the remaining time-domain resources {0~Nsym1-1, Nsym1+Nsym, excluding SRS-occupied symbols} are the following: 12 ~Nsym-1}.

[0076] The protocol stack only schedules other uplink channels within the two types of idle resources mentioned above, and SRS does not allocate any uplink transmission resources in the time and frequency domain throughout the entire process.

[0077] like Figure 2 As shown, taking a dual-terminal scheduling scenario as an example, the current time slot has a total schedulable frequency domain resource block range of 0-131 and a time domain symbol range of 0-13, including both the first and second terminals. The first terminal is in non-long-distance mode, with SRS receiving resources consisting of initial resource block RB=0, 20 consecutive resource blocks RB (i.e., resource blocks RB(0-19)), and symbol 12. The second terminal is in long-distance mode, with SRS receiving resources consisting of initial resource block RB=16, 40 consecutive resource blocks RB (i.e., resource blocks RB(16-55)), and occupied consecutive time domain symbols 9-13.

[0078] The total SRS resource usage is obtained by taking the union of the SRS resources occupied by the two terminals. That is, symbols 9, 10, 11, and 13 only occupy resource blocks RB (16~55); the two resource segments at symbol 12 overlap and are merged into resource block RB (0~55).

[0079] Therefore, the three sets of non-SRS scheduling resources available for scheduling the remaining uplink channels are: Frequency domain {0~131} and time domain {0~8}, frequency domain {55~131} and time domain {9~13} and frequency domain {0~15} and time domain {9, 10, 11, 13}.

[0080] The protocol stack configures uplink channels in three idle resource segments, and relies on resource isolation to completely eliminate time-frequency interference between multi-terminal SRS and ordinary uplink signals, adapting to the networking requirements of long-distance distributed base stations.

[0081] Example 2 like Figure 3 As shown, this embodiment provides a distributed network SRS receiving and processing system, including a network module and a terminal module connected to each other. The network module includes multiple radio frequency units and wireless access units. The wireless access unit includes a protocol stack and a baseband processing unit. The protocol stack is connected to the baseband processing unit, and the baseband processing unit is connected to each radio frequency unit through a fronthaul interface.

[0082] The protocol stack, acting as the centralized configuration and control node of the system, independently configures the first and second SRS reception parameters and distributes them to the baseband processing unit. This independent configuration mechanism grants the protocol stack differentiated management capabilities over the parameters of the baseband processing unit (BBU) and the radio frequency unit (RU), enabling fine-grained control of the configuration and avoiding processing logic coupling caused by different nodes sharing parameter sets.

[0083] After receiving the first SRS receive parameter and the second SRS receive parameter from the protocol stack, the baseband processing unit (BBU) forwards the received second SRS receive parameter to the corresponding radio frequency unit (RU). As the aggregation node of the fronthaul interface, the BBU undertakes the relay responsibility for parameter forwarding, thus eliminating the need for the protocol stack to communicate directly with each RU, reducing the interface complexity of the protocol stack. Simultaneously, the BBU can uniformly manage parameter forwarding based on the fronthaul interface status, which is beneficial for maintaining parameter configuration consistency when the number of RUs changes dynamically.

[0084] The radio frequency unit preprocesses the received uplink SRS signal according to the second SRS reception parameters and transmits the preprocessed signal back to the baseband processing unit. Each RU independently completes local preprocessing, sharing part of the processing load of the baseband processing unit (BBU), reducing the bandwidth requirements of the fronthaul link, and shortening the signal processing delay path. The multi-RU parallel preprocessing mechanism enables the system to have good horizontal scalability, supporting the addition of RUs as needed to expand the coverage area. Moreover, newly added RUs only need to obtain the second SRS reception parameters from the baseband processing unit (BBU) to participate in the operation, making the access process simple.

[0085] After the baseband processing unit aggregates the preprocessed signals from all radio frequency units (RUs), it performs SRS detection on the preprocessed signals returned by each radio frequency unit according to the first SRS receiving parameters.

[0086] In summary, this invention independently configures the first SRS receiving parameters of the baseband processing unit and the second SRS receiving parameters of the radio frequency unit through the protocol stack. It distinguishes between long-distance and non-long-distance operating modes based on the distance and power parameters between the terminal and each radio frequency unit, adaptively configures SRS protection symbols before and after transmission, and uses the protection symbols to offset the signal delay distortion caused by long-distance transmission, effectively suppressing SRS inter-symbol interference in large-spacing networking scenarios. At the same time, it integrates SRS transmission resources and reception resources to define a complete occupied interval, avoids scheduling uplink channels for SRS occupied resources, reduces time-frequency interference, and ensures SRS detection accuracy.

[0087] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for receiving and processing SRS in a distributed network, characterized in that, include: The protocol stack configures the SRS transmission parameters for the terminal and independently configures the first SRS reception parameters of the baseband processing unit and the second SRS reception parameters of the radio frequency unit. The radio frequency unit preprocesses the received uplink SRS signal according to the second SRS receiving parameters and sends it to the baseband processing unit. The baseband processing unit performs SRS detection on the preprocessed SRS signals returned by each radio frequency unit according to the first SRS receiving parameters. When scheduling the first SRS reception parameters and the second SRS reception parameters, the protocol stack dynamically determines the SRS reception resources based on at least one channel state parameter between the terminal and the radio frequency unit.

2. The SRS receiving and processing method in a distributed network as described in claim 1, characterized in that, The SRS receiving resource contains K+n+m consecutive OFDM symbols in the time domain, where K symbols are SRS symbols sent by the terminal, n symbols are SRS front protection symbols, and m symbols are SRS rear protection symbols, where n is an integer greater than or equal to 0 and m is an integer greater than or equal to 1. The front protection symbol and the rear protection symbol together constitute the SRS receive resource protection band; Within the time-frequency resource range corresponding to the SRS receive resource protection band, the protocol stack does not schedule any other uplink channels and uplink signals of any terminal; when the base station performs reception processing, it extracts all the time-frequency resources corresponding to the SRS receive resource protection band and performs reception and demodulation operations uniformly.

3. The SRS receiving and processing method in a distributed network as described in claim 1, characterized in that, The first SRS receiving parameters include the first terminal ID, the baseband processing unit ID, the first radio frequency unit ID, and the first SRS resource location; The first SRS resource location corresponds to the set of frequency domain RBs and the set of time domain continuous OFDM symbols occupied by the terminal; The first SRS resource location includes the first SRS frequency domain resource location, the first SRS time domain resource location, and the first SRS sequence parameters; The first SRS frequency domain resource location includes the starting resource block (RB), the number of persistent resource blocks, and the SRS resource unit (RE) offset; The first SRS time-domain resource location includes the SRS start symbol and the SRS persistence symbol; The first SRS sequence parameters include sequence group, sequence number, and sequence ID, which are used by the baseband processing unit to generate terminal-level SRS reference sequences; The first SRS receiving parameter is configured independently of the SRS parameters sent by the terminal.

4. The SRS receiving and processing method in a distributed network as described in claim 1, characterized in that, The second SRS receiving parameters include the second terminal ID, the second radio frequency unit ID, the second SRS resource location, the SRS radio frequency unit processing configuration parameters, and the SRS backhaul forward transmission length. The second SRS resource location includes a second SRS frequency domain resource location and a second SRS time domain resource location; The second SRS frequency domain resource location includes the starting resource block RB, the number of persistent resource blocks, and the SRS resource unit RE offset; The second SRS time-domain resource location includes both an SRS start symbol and an SRS persistence symbol; The second SRS receiving parameters are simultaneously sent to the baseband processing unit, which adaptively matches the corresponding SRS receiving processing mode according to the configuration of the second SRS receiving parameters.

5. The SRS receiving and processing method in a distributed network as described in claim 4, characterized in that, The SRS radio frequency unit processing configuration parameters include SRS transmission type indication, de-CP indication, FFT indication, and downsampling indication; The radio frequency unit performs preprocessing according to the SRS radio frequency unit processing configuration parameters in any of the following ways: When the SRS transmission type is a time-domain signal, no CP removal processing and FFT processing are performed; only downsampling processing is performed. When the SRS transmission type is a time-domain signal, CP removal processing is performed, FFT processing is not performed, and only downsampling processing is performed. When the SRS transmission type is a frequency domain signal, CP removal processing, FFT processing, and downsampling processing are performed.

6. The SRS receiving and processing method in a distributed network as described in claim 1, characterized in that, The channel state parameters include the distance difference between the terminal and each radio frequency unit, the received power, the moving speed, and the location information; The protocol stack determines whether the terminal is in long-range mode or non-long-range mode based on the channel state parameters, and determines the number of front protection symbols and rear protection symbols based on the decision result.

7. The SRS receiving and processing method in a distributed network as described in claim 6, characterized in that, The protocol stack determines whether the terminal is in long-distance mode or non-long-distance mode, specifically including: Assuming the radio frequency unit is i, the distance between the terminal and the radio frequency unit is d(i), and the power value measured by the radio frequency unit is a(i), the power value includes at least one of RSRP, SNR, SINR or RSSI; Select radio frequency units whose power value a(i) is greater than or equal to the first power threshold to form a set of candidate radio frequency units; Calculate the relative distance d(i,j) = |d(i) - d(j)| from any two radio frequency units i and j in the candidate set to the terminal, and take the maximum value max(d(i,j)) in the set. If max(d(i,j)) is less than the lowest order distance threshold, the terminal is determined to be in non-long-range mode, and the number of processing symbols of SRS receiving resources is configured to 1 symbol, i.e. n=0, m=0; If max(d(i,j)) is located within the interval formed by any two adjacent distance thresholds, then the terminal is determined to be in long-range mode. Based on the distance threshold interval into which max(d(i,j)) falls, the number of processing symbols for SRS receiving resources is configured to be K+n+m symbols, where n≥0 and m≥1.

8. The SRS receiving and processing method in a distributed network as described in claim 7, characterized in that, When the terminal is closest to one of the radio units in the set of candidate radio units, and the power value of the radio unit is not lower than the second power threshold, regardless of the value of the maximum value max(d(i,j)) in the set, the number of front protection symbols of the terminal is configured as n=0 and the number of rear protection symbols is configured as m≥1, that is, the number of symbols processed by the SRS receiving resources is K+m symbols.

9. The SRS receiving and processing method in a distributed network as described in claim 1, characterized in that, For each terminal in the current time slot, the protocol stack merges the two ranges according to the time domain symbol range and frequency domain resource range corresponding to the SRS receiving resources, and the transmission time domain symbol range and frequency domain resource range corresponding to the SRS transmission parameters configured by the protocol stack for the terminal, to obtain the SRS resource set occupied by a single terminal. The protocol stack performs a union operation on the SRS resource sets corresponding to all terminals in the same time slot to generate the total SRS resource set. The protocol stack avoids the time-frequency resources corresponding to the total SRS occupied resource set and schedules the remaining uplink channels on the remaining idle time-frequency resources; The protocol stack schedules other uplink channels on time-frequency resources outside the time-frequency range corresponding to the total SRS occupied resource set.

10. A distributed network SRS receiving and processing system, characterized in that, The device includes a network module and a terminal module connected to each other. The network module includes multiple radio frequency units and wireless access units. The wireless access unit includes a protocol stack and a baseband processing unit. The protocol stack is connected to the baseband processing unit. The baseband processing unit is connected to each radio frequency unit through a fronthaul interface. The protocol stack independently configures the first SRS receiving parameters and the second SRS receiving parameters, and sends the first SRS receiving parameters and the second SRS receiving parameters to the baseband processing unit. The baseband processing unit sends the received second SRS receiving parameters to the corresponding radio frequency unit; The radio frequency unit preprocesses the received uplink SRS signal according to the second SRS receiving parameters, and sends the preprocessed signal back to the baseband processing unit. The baseband processing unit performs SRS detection on the preprocessed signals returned by each radio frequency unit based on the first SRS receiving parameters.

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