Method and apparatus for intermodulation correction

Abstract

The embodiment of the present application provides a kind of intermodulation correction method and device, it is applied to distributed base station, the distributed base station includes convergence unit and radio frequency remote unit, convergence unit includes first processing unit, transmitting end, receiving hybrid unit, the method includes: first processing unit receives first correction signal, first correction signal is transmission signal, or, first correction signal is the signal received from receiving channel, first intermodulation interference signal is obtained by the receiving hybrid unit to the second intermodulation interference signal received from radio frequency remote unit and is hybrid;First processing unit carries out nonlinear cancellation to first correction signal and exports second correction signal, second correction signal is used to subtract or add with first intermodulation interference signal or send to receiving channel, receiving channel sends the signal to first processing signal, i.e. first correction signal for next cycle.The method and device provided in the application can effectively reduce processing cost and save resources.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of communications, and more particularly, to a method and apparatus for intermodulation correction. BACKGROUND

[0002] In a wireless communication system, a wireless communication base station system is to perform baseband algorithms by a base band unit (BBU), and can interact with a baseband signal with a radio remote unit (RRU) through a common public radio interface (CPRI) interface, and then the RRU transmits a downlink signal to an antenna through a feeder. However, due to non-ideal factors of some analog devices such as a cable, a diplexer or a feed, intermodulation such as passive inter-modulation (PIM) or active interference can be generated between multiple downlink signals. In some frequency point configurations, the frequency of the intermodulation can be the same as or close to the frequency of a useful signal, and the low-order intermodulation generated by the downlink signal can hit an uplink receiving frequency band, that is, the frequency of the generated intermodulation interference and the frequency of the uplink reception are all or partially overlapped, and thus a kind of interference is caused to the communication system.

[0003] For example, in order to solve the active intermodulation, a DUP with high isolation can be used to solve the problem, but the module output power consumption will also be affected; or an explicit cancellation scheme is used, and a feedback channel needs to be set to achieve the scheme, which increases the processing cost. For another example, in order to solve the passive intermodulation, one-to-one nonlinear cancellation is performed independently by each module, which is high in deployment cost and large in resource consumption. Moreover, as the number of channels in the distributed base station increases, the cost of solving the active intermodulation and the passive intermodulation will be higher and higher, and the level of module power consumption and cost will also be higher and higher. Therefore, how to realize the intermodulation correction with low cost and low power consumption in a multi-RRU combining scenario becomes a problem to be solved. SUMMARY

[0004] Embodiments of the present application provide a method for intermodulation correction, which can effectively reduce the processing cost and save resources.

[0005] In a first aspect, a method for intermodulation correction is provided, applied to a distributed base station, wherein the distributed base station includes a convergence unit and a radio remote unit, the convergence unit includes a first processing unit, a transmitting end, and a receiving combining unit, and the method includes:

[0006] The first processing unit receives a first correction signal, the first correction signal being a transmission signal from the sending end, or the first correction signal being a signal obtained by subtracting or adding a first intermodulation interference signal output by the receiving combining unit from a signal output by the first processing unit, the first intermodulation interference signal being obtained by combining, by the receiving combining unit, a second intermodulation interference signal received from the radio frequency remote unit;

[0007] The first processing unit outputs a second correction signal according to the first correction signal, the second correction signal being obtained by performing nonlinear cancellation on the first correction signal by the first processing unit, and the second correction signal being used for subtraction or addition with the first intermodulation interference signal.

[0008] The above scheme solves intermodulation interference and feedback channels by using a centralized resource pool, and can effectively reduce processing cost and save resources.

[0009] With reference to the first aspect, in some implementations of the first aspect, the method further includes:

[0010] The first processing unit receives an i-th first correction signal, the i-th first correction signal being obtained by adding or subtracting an (i-1)-th first intermodulation interference signal and an (i-1)-th second correction signal, i being a positive integer greater than 1;

[0011] The first processing unit outputs an i-th second correction signal according to the i-th first correction signal, the i-th second correction signal being obtained by performing nonlinear cancellation on the i-th second correction signal by the first processing unit.

[0012] With reference to the first aspect, in some implementations of the first aspect, the first processing unit sends indication information to the radio frequency remote unit, the indication information being used to indicate processing of a received signal, the processing including linear cancellation or nonlinear cancellation of the received signal to obtain the second intermodulation interference signal.

[0013] Secondly, a method for intermodulation correction is provided, and is applied to a distributed base station, wherein the distributed base station includes a convergence unit and a radio frequency remote unit, the radio frequency remote unit includes at least two modules, and the method includes:

[0014] The radio frequency remote unit receives indication information from the convergence unit, the indication information being used to indicate processing of a received signal;

[0015] The radio remote unit processes the at least two received signals according to the indication information to obtain at least two second intermodulation interference signals, wherein each second intermodulation interference signal is obtained by processing one received signal by each module, the processing includes linear intermodulation or nonlinear intermodulation, and the at least two second intermodulation interference signals can be subjected to nonlinear cancellation processing by the first processing unit in the convergence unit.

[0016] The radio remote unit sends the at least two second intermodulation interference signals to the convergence unit.

[0017] The above scheme solves intermodulation interference and feedback channels by using a centralized resource pool, which can effectively reduce processing cost and save resources.

[0018] In a third aspect, a device for intermodulation correction is provided, which comprises a convergence unit and a radio remote unit, the convergence unit comprises a first processing unit, a transmitting end, a receiving combining unit,

[0019] The first processing unit is configured to receive a first correction signal, the first correction signal being a transmitting signal from the transmitting end, or the first correction signal being a signal obtained by subtracting or adding a signal output by the first processing unit from a first intermodulation interference signal output by the receiving combining unit, the first intermodulation interference signal being obtained by combining, by the receiving combining unit, a second intermodulation interference signal received from the radio remote unit, the second intermodulation interference signal being from different modules of the radio remote unit.

[0020] The first processing unit is further configured to output a second correction signal according to the first correction signal, the second correction signal being obtained by nonlinear cancellation of the first correction signal by the first processing unit, and the second correction signal being used for subtraction or addition with the first intermodulation interference signal.

[0021] In combination with the third aspect, in some implementations of the third aspect, the first processing unit is further configured to receive an i-th first correction signal, the i-th first correction signal being obtained by adding or subtracting an (i-1)-th first intermodulation interference signal from an (i-1)-th second correction signal, i being a positive integer greater than 1.

[0022] The first processing unit is further configured to output an i-th second correction signal according to the i-th first correction signal, the i-th second correction signal being obtained by nonlinear cancellation of the i-th second correction signal by the first processing unit.

[0023] In some implementations of the third aspect, the first processing unit is further configured to send indication information to the radio remote unit, the indication information indicating that the received signals are to be processed, the processing including linear or nonlinear cancellation to obtain the at least two second intermodulation interference signals.

[0024] In a fourth aspect, an apparatus for intermodulation correction is provided. The apparatus includes a convergence unit and a radio remote unit, the radio remote unit including at least two modules,

[0025] The radio remote unit is configured to receive indication information from the convergence unit, the indication information indicating that the received signals are to be processed.

[0026] The radio remote unit is further configured to process the at least two received signals according to the indication information to obtain at least two second intermodulation interference signals, wherein each of the second intermodulation interference signals is obtained by processing one of the received signals by each of the modules, the processing including linear or nonlinear intermodulation, and the at least two second intermodulation interference signals are to be nonlinearly cancelled by a first processing unit in the convergence unit.

[0027] The radio remote unit is further configured to send the at least two second intermodulation interference signals to the convergence unit.

[0028] In a fifth aspect, a communication system is provided. The communication system includes the apparatus of the third aspect or the fourth aspect.

[0029] In a sixth aspect, a distributed base station is provided. The distributed base station includes the apparatus of the third aspect or the fourth aspect and a baseband unit.

[0030] In a seventh aspect, an optical communication apparatus is provided. The optical communication apparatus includes a processor and a communication interface. The processor is coupled to a memory via the communication interface. The processor is configured to execute program code in the memory to implement the method of the first aspect or the second aspect.

[0031] In an eighth aspect, a chip is provided. The chip includes programmable logic circuitry and / or program instructions. When the chip is running, the programmable logic circuitry and / or program instructions are configured to implement the method of the first aspect or the second aspect.

[0032] In a ninth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program. When the computer program is running on a computer, the computer program causes the computer to perform the method of the first aspect or the second aspect.

[0033] In a tenth aspect, a computer program is provided, characterized in that, when executed on a computer, the computer program causes the computer to perform the method as described in the first or second aspect. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the architecture of a distributed base station.

[0035] Figure 2 A schematic block diagram illustrating a basic structure of a distributed base station is shown.

[0036] Figure 3 This diagram illustrates an example of the principle of intermodulation correction performed by distributed base stations.

[0037] Figure 4 The method 100 for intermodulation correction provided in this application is shown.

[0038] Figure 5 A schematic diagram illustrating the basic principle of intermodulation correction provided in this application is shown.

[0039] Figure 6 A further schematic diagram illustrating the basic principle of intermodulation correction provided in this application is shown.

[0040] Figure 7 This is a schematic diagram of an example of an intermodulation correction device applicable to this application.

[0041] Figure 8 This is another schematic diagram of an intermodulation correction device applicable to this application. Detailed Implementation

[0042] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0043] The technical solutions of this application embodiment can be applied to various communication systems, such as 5th generation (5G) systems, new radio (NR) systems, and long term evolution (LTE) systems (e.g., LTE frequency division duplex (FDD) systems and LTE time division duplex (TDD) systems). Furthermore, the technical solutions of this application embodiment can also be applied to sidelink communication. For example, the technical solutions of this application embodiment can also be applied to device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC) communication, and communication in vehicle-to-everything (V2X) systems.

[0044] For the convenience of understanding, an example architecture diagram of a distributed base station capable of implementing the communication method of the embodiments of the present application is described in the whole. It should be understood that the embodiments of the present application are not limited to Figure 1 In the system architecture shown, the system to which the signal processing method and the distributed control device of the embodiments of the present application can be applied can further include other devices or units, in addition to Figure 1 The device in the above can be hardware, or software functionally divided, or a combination of the above two.

[0045] The BBU 110 is a baseband processing unit (BBU) that centrally controls and manages the whole base station system and implements baseband signal processing. The DCU 120 supports RF source feeding and can also receive signals transmitted by the BBU 110. The base transceiver station (BTS) 130 can feed RF signals to the DCU 120.

[0046] The pRRU 150 is an indoor low-power radio remote unit (RRU) responsible for transmitting and processing radio frequency signals between the BBU 110 or the BTS 130 and the antenna feeder system.

[0047] At present, network systems use a large number of distributed base station architectures, and the RRU (radio remote module) and the BBU (baseband processing unit) in the distributed base station need to be connected by optical fibers. One BBU can support multiple RRUs.

[0048] Specifically, in a wireless communication system, the wireless communication base station system is executed by the BBU to perform baseband algorithms, which can interact with the RRU through a common public radio interface (CPRI) interface to transmit baseband signals, and then the RRU transmits the downlink transmission signals to the antenna through the feeder. However, due to some non-ideal factors of analog devices such as cables, duplexers or antenna feeders, multiple downlink transmission signals will produce intermodulation, such as passive intermodulation (PIM). In some frequency point configurations, the frequency of the intermodulation can be the same or close to the frequency of the useful signal. The low-order intermodulation generated by the downlink transmission signal can hit the uplink reception frequency band, that is, the frequency of the intermodulation interference generated is all or partially overlapped with the uplink reception frequency, thus causing an interference to the communication system.

[0049] In order to facilitate the description of the present scheme, some technical terms related to the present application are introduced below.

[0050] 1. Radio frequency power amplifier (RF PA): As the main component of the RF front-end transmission path, it is mainly used to amplify the low-power RF signal generated by the modulation oscillation circuit to obtain a sufficiently large RF output power so that it can be fed to the antenna for radiation. It is usually used to amplify the RF signal in the transmission channel.

[0051] 2. Duplexer (DUP): A duplexer is a key component of a multi-frequency duplex radio or repeater. Its function is to isolate the transmitted and received signals, ensuring that both transmission and reception can function normally simultaneously. It consists of two sets of bandpass filters at different frequencies, preventing the transmitted signal from reaching the receiver.

[0052] 3. Antenna (ANT): An antenna is a transducer that converts guided waves propagating on a transmission line into electromagnetic waves propagating in an unbounded medium (usually free space), or vice versa. It is a component in wireless equipment used to transmit or receive electromagnetic waves. Engineering systems such as radio communication, broadcasting, television, radar, navigation, electronic countermeasures, remote sensing, and radio astronomy—anything that uses electromagnetic waves to transmit information—rely on antennas. Furthermore, antennas are also needed for non-signal energy radiation in the transmission of energy using electromagnetic waves. Generally, antennas are reversible, meaning the same antenna can be used as both a transmitting and receiving antenna. The basic characteristic parameters of the same antenna are identical whether it is used for transmitting or receiving. This is the reciprocity theorem of antennas.

[0053] 4. Combiner: The combiner is mainly used at the receiving end. Its function is to combine two or more radio frequency signals from different remote units into one signal and send it to the baseband unit, while avoiding mutual interference between the signals of each port.

[0054] 5. Intermodulation Interference: Due to non-ideal factors of some analog devices, such as cables, duplexers, or antenna feeders, intermodulation can occur between multiple downlink transmitted signals, such as passive intermodulation. Under certain frequency configurations, the frequency of intermodulation may be the same as or close to the frequency of the useful signal. The low-order intermodulation generated by the downlink transmitted signal can hit the uplink receiving frequency band, meaning that the frequency of the intermodulation interference completely or partially overlaps with the frequency of the uplink receiving signal, thus causing interference to the communication system.

[0055] 6. Active intermodulation: Intermodulation generated by active devices is called active intermodulation.

[0056] 7. Passive inter-modulation (PIM): PIM is similar to active inter-modulation, except that PIM is generated by passive devices. Inter-modulation occurs whenever two or more RF signals are present in a RF conductor at the same time. Any passive device will generate PIM products when more than one frequency is present in the device. Due to the non-linearity at the junctions of different materials, the signals mix at the junctions. Typically, the odd order inter-modulation products (e.g. IM3 = 2*Fl - F2) fall within the uplink or receive band of the base station and become interfering signals to the receiver. It causes receiver desensitization independent of the receiver's random noise floor.

[0057] 8. Inter-modulation distortion (IMD): IMD refers to the distortion introduced by an amplifier of the sum and difference of the input signals. For example, after a mixed signal is input to an amplifier, IMD components are generated. IMD refers to the distortion caused by the modulation of signals with each other. The word modulation originally refers to a technique used in communication technology to improve the efficiency of signal transmission. Since the original signals containing sound, image, and text are added to high frequency signals, and then the combined signal is transmitted at the same time. This process and method of adding high and low frequencies are called modulation technology, and the combined signal is called a modulated signal. In addition to retaining the main characteristics of high frequency signals, modulated signals also contain all the information of low frequency signals. The process of generating IMD is essentially a modulation process. Since an electronic circuit or an amplifier cannot be completely linear, when different frequency signals are simultaneously input to the amplifier for amplification, each different frequency signal will automatically add and subtract under the action of non-linearity, generating two additional signals that are not in the original signal. If there are three different frequencies in the original signal, there will be six additional signals. When there are N original signals, there will be N(N-1) additional signals. It can be imagined that when the input signal is a complex multi-frequency signal, such as an orchestra, the number of additional signals generated by IMD will be very large.

[0058] 9. Linear cancellation: Using the linear correlation between the reference signal and the interference signal, the interference cancellation problem is solved by linear fitting.

[0059] 10. Non-linear cancellation: Using the non-linear relationship between the reference signal and the interference signal, the interference cancellation problem is solved by non-linear fitting.

[0060] The following will be further introduced Figure 2 The units and modules involved in the distributed base station will be further introduced. Figure 2 An example of a schematic block diagram showing the basic structure of a distributed base station is shown.

[0061] AsFigure 2 As shown, the transmitting end Tx of the convergence module transmits signals to the transmitting end Tx of the RRU, the RRU transmits the signals received by the receiving end Rx to the Rx of the convergence element (CE) through the receiving channel of the RRU, and then the convergence element transmits the received signals to the BBU after processing. Specifically, in the RRU, taking module 1 as an example, the transmitting end Tx receives signal 01, transmits it to the RF PA, and transmits it to the DUP after processing by the RF PA. The non-linear cancellation processing unit outputs the signal after non-linear cancellation processing of the transmitting signal received from the transmitting end Tx, and the signal received by the receiving end Rx and the signal output by the non-linear cancellation processing unit are subtracted to obtain error, which is transmitted to the receiving channel. Then, the output error is subjected to non-linear cancellation processing by the non-linear cancellation processing unit, and then subtracted from the signal received by the receiving end Rx and transmitted to the receiving channel. According to this process, it is circulated until the appropriate signal is obtained and transmitted to the Rx of the convergence element by the receiving channel.

[0062] It should be noted that, Figure 2 The RRU is illustrated by taking modules 1 and 2 as examples, but the number of modules in the RRU is not limited in the present application.

[0063] Because the RF PA, DUP or ANT can cause intermodulation active or passive intermodulation between multiple downlink transmission signals, thereby causing intermodulation interference and affecting the sensitivity of the receiving end. The common intermodulation correction method is to deploy a non-linear module cancellation processing unit or a linear cancellation processing unit in the RRU to solve the problem of intermodulation interference. Currently, multi-RRU radio frequency combining is a common technology, and in the multi-RRU combining scene, intermodulation correction is generally performed by linear cancellation or one-to-one non-linear cancellation in the RRU.

[0064] The following will be described in detail Figure 3 Some intermodulation correction schemes are introduced from the aspects of solving active intermodulation and passive intermodulation.

[0065] To solve active intermodulation, a DUP with high isolation can be used, but it will also affect the module output power consumption; or an explicit cancellation scheme is adopted, which requires a feedback channel (for example Figure 3 between the PA and the DUP, and between the DUP and the Rx) to be set to achieve it, which increases the processing cost. To solve passive intermodulation, one-to-one non-linear cancellation is performed independently by each module (for example Figure 3The module 1 and the module 2 in the figure are both provided with a nonlinear module cancellation processing unit, so that the deployment cost is high, and the resource consumption is large. Moreover, with the increase of the channel number in the distributed base station, the cost of solving the active intermodulation and the passive intermodulation is larger and larger, and the power consumption and the cost level of the module are higher and higher, so that how to realize the intermodulation correction with low cost and low power consumption in the multi-RRU combining scene becomes a problem to be solved urgently.

[0066] The method 100 for intermodulation correction provided in the present application will be described below in combination with Figure 4 The method 100 for intermodulation correction provided in the present application will be described below in combination with Figure 4 The figure is a schematic flowchart of the method 100 for intermodulation correction provided in the embodiment of the present application, which is applied to a distributed base station, and the distributed base station includes a convergence unit and a radio frequency remote unit. The convergence unit includes a first processing unit, a transmitting end, and a receiving combining unit. The method 100 specifically includes the following steps:

[0067] S101, the first processing unit receives a first correction signal.

[0068] Exemplarily, the first processing unit can be Figures 5 to 6 The nonlinear model cancellation processing unit in the convergence unit in the figure, and the introduction of the nonlinear model cancellation processing unit can be specifically referred to the corresponding description in Figure 5 and Figure 6

[0069] S102, the first processing unit outputs a second correction signal according to the first correction signal.

[0070] The second correction signal is obtained by the first processing unit performing nonlinear cancellation on the first correction signal. The introduction of the nonlinear cancellation can be specifically referred to the corresponding description in Figure 5 and Figure 6

[0071] It should be understood that in the method 100, S101 and S102 are executed M times, and M is a positive integer greater than or equal to 2.

[0072] When the first time is executed, the first correction signal in S101 is a transmitting signal from the transmitting end. From the mth time (i is a positive integer greater than 1 and less than or equal to M), the first correction signal in S101 is a signal obtained by subtracting or adding the signal output by the first processing unit and the first intermodulation interference signal output by the receiving combining unit. The signal output by the first processing unit is the (i-1)th second correction signal output in the (i-1)th time. The signal obtained by adding or subtracting the (i-1)th second correction signal and the first intermodulation interference signal is sent to the first processing unit through the receiving channel of the convergence unit, and the signal sent to the first processing unit through the receiving channel of the convergence unit is the ith first correction signal, and then the (i+1)th cycle is continued. ​​

[0073] Exemplarily, the second intermodulation interference signal here can be from different modules of the radio remote unit, to Figure 3 For example, the second intermodulation interference signal 01 can be sent by module 1 of the radio remote unit to the Rx combiner of the convergence unit through the receiving channel, and the second intermodulation interference signal 02 can be sent by module 2 to the Rx combiner of the convergence unit through the receiving channel.

[0074] Optionally, the radio remote unit includes at least 2 modules, and the method 100 further includes:

[0075] Step 1: The first processing unit sends indication information to the radio remote unit, and correspondingly, the radio remote unit receives the indication information from the convergence unit, and the indication information is used to indicate processing of the received signal, where the processing includes linear cancellation or nonlinear cancellation to obtain the second intermodulation interference signal.

[0076] It should be understood that the indication information here can be sent or transmitted by the convergence unit to the radio remote unit through the control unit, or the control unit can also be realized by a virtual interface between the radio remote unit and the convergence unit.

[0077] Step 2: The radio remote unit processes at least 2 received signals according to the indication information to obtain at least 2 second intermodulation interference signals, wherein each second intermodulation interference signal is obtained by processing 1 received signal by each module, and the processing includes linear intermodulation or nonlinear intermodulation, and the at least 2 second intermodulation interference signals can be processed by the first processing unit in the convergence unit.

[0078] It should be understood that each module of the radio remote unit processes the received signal, and each module obtains one second intermodulation interference signal, but the processing performed by each module and the second intermodulation interference signal obtained by each module can be different. Exemplarily, each module can include a transmitting end, a receiving end, a radio frequency amplifier, a duplexer, an antenna, and the like. Due to the hardware differences between different modules, the differences in the signals received by the receiving ends of different modules can be different. If the difference is a nonlinear difference, for example, a difference caused by the nonlinear constituting mechanism of the device, etc., then the processing of the module needs to include nonlinear fitting, and if the difference is a linear difference, for example, flatness, time delay jitter, etc., then the processing of the module needs to include nonlinear fitting.

[0079] It should also be understood that before obtaining the second intermodulation interference signal, whether the received signal and the processing of the received signal are consistent or not, the second intermodulation interference signal obtained by each module can be nonlinearly fitted by the same nonlinear model, and the first processing unit of the convergence unit is the nonlinear model.

[0080] Step 3: The radio remote unit sends at least two second intermodulation interference signals to the convergence unit.

[0081] Exemplarily, the radio remote unit sends the second intermodulation interference signals to the receiving combiner of the convergence unit, and correspondingly, the convergence unit receives the second intermodulation interference signals. The subsequent steps can refer to the corresponding description in S102.

[0082] In summary, compared with the one-to-one nonlinear cancellation processing performed by each module independently, the above scheme first calculates the nonlinear difference part caused by the difference of the radio frequency devices in the intermodulation interference by each module in the RRU, and then sends it to the convergence unit for centralized resource pooling and nonlinear fitting, so that the multiple modules in the co-cell complete the cancellation processing under the coordination of the convergence unit. This can greatly simplify the modules and algorithms of the nonlinear model cancellation processing unit of each module deployment, reduce the deployment cost and resource consumption. Even in the case of increasing number of channels in the distributed base station, it can also reduce the cost and save resources. Compared with setting a feedback channel between multiple radio frequency devices, the above scheme does not need to set a feedback channel, further saving processing cost. Compared with setting a duplexer with high isolation, the above scheme also does not need to set a duplexer with high isolation, avoiding affecting the module output function, further reducing the cost and saving resources.

[0083] Therefore, the above scheme can effectively reduce the processing cost and save resources by using centralized resources to solve intermodulation interference and feedback channels.

[0084] The above introduces the method 100 of intermodulation correction provided by the present application, and the principle of intermodulation correction provided by the present application is introduced as follows.

[0085] The overall design scheme can be summarized as follows: a simplified linear / nonlinear model cancellation processing unit is deployed in each module of the RRU, which is used to process the difference part of the first IDM generated by different modules due to the difference in hardware performance between modules, so that the output second IMD can be processed by the same nonlinear module cancellation unit. Each module in the RRU sends the output second IMD to the convergence unit, and the nonlinear cancellation processing unit of the convergence unit processes the second IMD and sends the processed signal to the BBU. It should be understood that, due to the different shipment time and batch of different modules in the RRU, there is a difference in hardware performance between modules, which will also cause differences in IMD generated by different modules. Among them, the difference part of the IMD generated by different modules includes a linear difference part and a nonlinear difference part.

[0086] It should also be understood that the intermodulation correction scheme provided by the present application requires the cascade processing of the nonlinear modules of the combiner module and the remote unit.

[0087] The following will be described in combination withFigure 5 An example of a schematic diagram illustrating the basic principle of the intermodulation correction provided by the present application is introduced.

[0088] As shown in Figure 5 , the convergence unit can first determine its non-linear model cancellation processing unit and the simplified non-linear model cancellation processing units in each module of the RRU based on the application needs of the scene or actual product, etc. The non-linear model cancellation processing unit of the convergence unit needs to solve the received signal several times to ensure that the final error is minimized. For example, two threshold values can be set. When the number of times of solving the received signal by the non-linear model cancellation processing unit of the convergence unit reaches the first threshold value, the solving is stopped. When the number of times of solving the received signal by the simplified non-linear model cancellation processing units of each module of the RRU reaches the second threshold value, the solving is stopped. The second threshold value can be sent to each module of the RRU by the control unit, and when each module of the RRU starts to solve, it can also be triggered by the indication sent by the control unit. As can be seen from the above, the convergence unit controls the RRU through the control unit. The control path of the control unit is represented by a dashed line in Figure 5 , which means that in specific implementation, it can be realized through a virtual interface between the convergence unit and the RRU. Similarly, the non-linear model cancellation processing unit of the convergence unit and the simplified non-linear model cancellation processing unit of module 2 in the RRU can also be controlled by the control unit, which is not shown in Figure 5 .

[0089] Subsequently, the sending end Tx of the convergence unit distributes the transmitted signal x to module 1 and module 2 in the RRU. Taking module 1 as an example, after the sending end Tx of module 1 receives the signal x, the signal f1(x) output after the simplified non-linear model cancellation processing unit is subtracted from the signal Y received by the receiving end Rx of module 1. Y-f1(x) is fed back to the simplified non-linear model cancellation processing unit by the receiving channel to continue solving to obtain f1'(x), which continues to be subtracted from the signal Y, f1'(x)=f1(Y-f1(x)). According to this process, after m-2 times of recirculation (for example, m is the second threshold value configured by the convergence unit to the RRU, and m is a positive integer), the receiving channel of module 1 outputs the signal f1 m (x) to the receiving combiner of the convergence unit. Similarly, the simplified non-linear model cancellation processing unit in module 2 also circulates the above process n times (for example, m is the second threshold value configured by the convergence unit to the RRU, and m is a positive integer, which can be equal to n or not equal to n), and outputs the signal f2 n(x) the received combined signal sent to the convergence unit. The simplified nonlinear model of each module in the cancellation unit can identify the nonlinear constitutive mechanism of different modules and the key influencing factors of different devices, and perform corresponding nonlinear fitting. The nonlinear fitting only accounts for a small part of the entire intermodulation correction process, for example, less than 20% of the entire process. Specifically, the proportion of the nonlinear fitting process in the intermodulation of the received signal is determined according to the indication sent by the control unit of the convergence unit. It should be noted that, Figure 2 The RRU is illustrated by taking module 1 and module 2 as examples, but the number of modules in the RRU is not limited in the present application. It is assumed that the RRU includes L modules, and L is greater than or equal to 2.

[0090] Exemplarily, f1(x) or f2(x) can be equal to a0*x n *abs(x n )+a1*X n-1 *abs(X n-1 )+a2*X n-2 *abs(x n-2 )+..... where the independent variable x n represents the delay of the transmitted signal X at time n, X n-1 represents the delay of the transmitted signal X at time n-1, abs(x n ) represents the absolute value of x n , and [a0 a1…a n ] can be obtained by solving the equations [a0 a1…a n ]*X=f1(x), [a0 a1…a n ]*f1(x)=f’1(x), and the like.

[0091] Then, the Rx combined signal of the convergence unit combines the signals received from different modules of the RRU to obtain the signal Y L =f1 m (x)+f2 n (x)+...... The sending end Tx in the convergence unit sends the transmitted signal X to the nonlinear model cancellation processing unit, and the output signal is f(x). f(x) is subtracted from Y L , and the result f’(x) is fed back to the nonlinear model cancellation processing unit through the receiving channel. f’(x)=Y L -f(x), the nonlinear model cancellation processing unit continues to solve f’(x) to obtain f’’(x), and after L-2 times of recirculation according to this process, the receiving channel sends f L (x) received to the BBU. It should be noted that in order to enable the signals processed by each module in the RRU to be combined and processed, the time delays of each module need to be aligned in advance.

[0092] For example, f(x) = b0*x n +b1*x n-1 +......b n-1 *x+b n By analyzing [b0 b1…b] n ]*X=f(x), [b0b1…b n Solving equations such as f(x) = f'(x) yields [b0 b1......], and the rest are similar to f1(x) or f2(x) mentioned above.

[0093] In summary, compared to performing one-to-one nonlinear cancellation processing independently for each module, the above scheme solves the nonlinear difference component caused by the differences in radio frequency devices in intermodulation interference through each module in the RRU, and then sends it to the aggregation unit for centralized resource pooling nonlinear fitting. This enables multiple modules in the same cell to complete cancellation processing in collaboration with the aggregation unit, which greatly simplifies the modules and algorithms of the nonlinear model cancellation processing units deployed in each module, reduces deployment costs, and reduces resource consumption. Even with the increasing number of channels in distributed base stations, it can still reduce costs and save resources. Compared to setting up feedback channels between multiple radio frequency devices, the above scheme does not require setting up feedback channels, further saving processing costs. Compared to setting up DUPs with high isolation, the above scheme also does not require setting up DUPs with high isolation, avoiding affecting the module output function, further reducing costs and saving resources.

[0094] Therefore, the above solution can effectively reduce processing costs and save resources by using a centralized resource pool to solve intermodulation interference and eliminate feedback channels.

[0095] The following is combined Figure 6 Another schematic diagram illustrating the basic principle of intermodulation correction provided in this application.

[0096] Figure 6 The example shown illustrates the basic principle of intermodulation correction. Figure 5 The example shown is similar. Figure 5 and Figure 6 The difference is that, Figure 6The example in the foregoing embodiment uses a simplified linear model cancellation processing unit in each module of the RRU. In this example, the simplified linear model cancellation processing unit is mainly used to solve the linear difference part in the IMD generated by different modules due to the difference of the radio frequency devices in different modules, such as flatness, time delay jitter, etc. These linear difference parts can be solved by the simplified linear model cancellation processing unit in each module using an initial table fixed solution or a linear iteration solution to obtain a signal that can be uniformly fitted by the nonlinear model cancellation processing unit of the convergence unit, and sent to the convergence unit. Similar to the example shown in Figure 5 , when each simplified linear model cancellation processing unit starts to solve, the number of times of solving can be controlled by the control unit of the convergence unit. Except for the above difference, the rest of the process can refer to the description of the example of Figure 5 .

[0097] In summary, compared with one-to-one nonlinear cancellation processing by each module independently, the above scheme solves the linear difference part in the intermodulation interference caused by the difference of the radio frequency devices in each module of the RRU, and sends it to the convergence unit for centralized resource pooling nonlinear fitting, so that multiple modules in the co-cell complete the cancellation processing under the coordination of the convergence unit. This can greatly simplify the module and algorithm of the nonlinear model cancellation processing unit of each module deployment, reduce the deployment cost and resource consumption. Even in the case of increasing number of channels in the distributed base station, it can also reduce the cost and save resources. Compared with setting a feedback channel between multiple radio frequency devices, the above scheme does not need to set a feedback channel, further saving processing cost. Compared with setting a DUP with high isolation, the above scheme also does not need to set a DUP with high isolation, avoiding affecting the module output function, further reducing the cost and saving the resources.

[0098] Therefore, the above scheme can effectively reduce the processing cost and save the resources by using centralized resources to solve the intermodulation interference and remove the feedback channel.

[0099] It should be noted that the intermodulation correction scheme provided by the present application can be used not only in distributed base stations but also in other architectures that need to correct intermodulation. The present application does not limit this.

[0100] The above describes the method embodiment of the intermodulation correction of the present application in detail in combination with Figures 1 to 6 , and the following will describe the device embodiment of the intermodulation correction of the present application in combination with Figure 7 and Figure 8 . It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, the parts not described in detail can refer to the foregoing method embodiment.

[0101] Figure 7This is a schematic block diagram of the intermodulation correction device provided in the embodiments of this application. Figure 7 As shown, the device 1000 may include a convergence unit 1100 and a radio frequency remote unit 1200.

[0102] It should be understood that the device 1000 may include tools for performing Figure 4 The unit of method 400 in the apparatus 1000. Furthermore, each unit in the apparatus 1000 and the other operations and / or functions described above are respectively for implementing... Figure 4 The corresponding process of method 400 in the middle.

[0103] In one possible implementation, the aggregation unit 1100 includes a first processing unit, a transmitting end, and a receiving combining unit.

[0104] The first processing unit is used to receive a first correction signal, which is a transmitted signal from the transmitting end, or the first correction signal is a signal obtained by subtracting or adding the signal output by the first processing unit and the first intermodulation interference signal output by the receiving combining unit. The first intermodulation interference signal is obtained by the receiving combining unit combining the second intermodulation interference signal received from the radio frequency remote unit 1200. The second intermodulation interference signals come from different modules of the radio frequency remote unit 1200.

[0105] The first processing unit is also configured to output a second correction signal based on the first correction signal. The second correction signal is obtained by the first processing unit after performing nonlinear cancellation on the first correction signal. The second correction signal is used to subtract from or add to the first intermodulation interference signal.

[0106] Optionally, the first processing unit is further configured to receive the i-th first correction signal, which is obtained by adding or subtracting the (i-1)-th first intermodulation interference signal and the (i-1)-th second correction signal, where i is a positive integer greater than 1;

[0107] The first processing unit is also configured to output the i-th second correction signal based on the i-th first correction signal, wherein the i-th second correction signal is obtained by the first processing unit performing nonlinear cancellation on the i-th second correction signal.

[0108] Optionally, the first processing unit is further configured to send indication information to the radio frequency remote unit 1200, the indication information being used to instruct the receiving signal to be processed, the processing including linear cancellation or nonlinear cancellation of the receiving signal to obtain at least two second intermodulation interference signals.

[0109] Another possible implementation is that the radio frequency remote unit 1200 includes at least two modules.

[0110] The radio frequency remote unit 1200 is used to receive indication information from the convergence unit 1100, the indication information being used to instruct the processing of the received signal;

[0111] The radio frequency remote unit 1200 is also used to process at least two received signals according to the indication information to obtain at least two second intermodulation interference signals, wherein each second intermodulation interference signal is obtained by each module processing one received signal, and the processing includes linear intermodulation or nonlinear intermodulation, and the at least two second intermodulation interference signals can be nonlinearly canceled by the first processing unit in the convergence unit 1100.

[0112] The radio frequency remote unit 1200 is also used to send at least two second intermodulation interference signals to the convergence unit 1100.

[0113] It should also be understood that the aggregation unit 1100 in the device 1000 can be implemented by at least one processor.

[0114] It should also be understood that the aggregation unit 1100 in the device 1000 can be implemented by a processor, microprocessor or integrated circuit integrated on the chip or chip system.

[0115] Figure 8 This is another schematic block diagram of the intermodulation correction device 2000 provided in the embodiments of this application. For example... Figure 8 As shown, the device 2000 includes a processor 2010, a transceiver 2020, and a memory 2030. The processor 2010, transceiver 2020, and memory 2030 communicate with each other via an internal connection. The memory 2030 stores instructions, and the processor 2010 executes the instructions stored in the memory 2030 to control the transceiver 2020 to transmit and / or receive signals.

[0116] It should be understood that the device 2000 can be used to perform the various steps and / or processes in the above method embodiments.

[0117] Optionally, the memory 2030 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. The memory 2030 may be a separate device or integrated into the processor 2010. The processor 2010 may be used to execute instructions stored in the memory 2030, and when the processor 2010 executes instructions stored in the memory, the processor 2010 is used to perform the various steps and / or processes of the method embodiments corresponding to the convergence unit and / or radio frequency remote unit described above.

[0118] The transceiver 2020 can include a transmitter and a receiver. The transceiver 2020 can further include an antenna, and the number of the antenna can be one or more. The processor 2010 and the memory 2030 and the transceiver 2020 can be integrated devices on different chips. For example, the processor 2010 and the memory 2030 can be integrated in a baseband chip, and the transceiver 2020 can be integrated in a radio frequency chip. The processor 2010 and the memory 2030 and the transceiver 2020 can also be integrated devices on the same chip. The present application does not make any limitation in this regard.

[0119] The transceiver 2020 can also be a communication interface, such as an input / output interface, a circuit, etc. The transceiver 2020, the processor 2010 and the memory 2030 can be integrated in the same chip, such as a baseband chip.

[0120] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art better understand the technical solutions of the present application, and the above specific implementation manners can be considered as the optimal implementation manner of the present application, but not limit the scope of the embodiments of the present application.

[0121] It should also be understood that in various embodiments of the present application, the size of the sequence number of the above processes does not mean the order of execution, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0122] It should be understood that in the above embodiments, only the dynamic intermodulation correction method flow provided by the present application is illustrated, and the protection scope of the present application is not limited in any way.

[0123] It should also be understood that in various embodiments of the present application, if there is no special description and logical conflict, the terms and / or descriptions of different embodiments can be consistent and can be mutually referred to, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0124] It should be appreciated that in embodiments of the present application, the processor can be a central processing unit (CPU), the processor can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor and the like.

[0125] It should also be appreciated that the memory in embodiments of the present application can be a volatile memory or a nonvolatile memory, or can include both volatile and nonvolatile memory. The nonvolatile memory can be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically EPROM (EEPROM), or a flash memory, among others. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example, and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0126] The method steps in the embodiments of the present application can be realized by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, so that the processor can read information from the storage medium and write information to the storage medium.

[0127] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0128] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0129] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be realized by other ways. For example, the device embodiments described above are merely schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0130] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e., they can be located in one place or distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the technical solutions of the embodiments of the present application.

[0131] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit.

[0132] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes various media that can store program codes, such as a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk.

[0133] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of intermodulation correction, applied to a distributed base station, characterized in that, The distributed base station comprises a convergence unit and a radio frequency remote unit, the convergence unit comprises a first processing unit, a transmitting end, a receiving combining unit, and the method comprises: The first processing unit receives a first correction signal, the first correction signal is a signal obtained by subtracting or adding a signal output by the first processing unit from a first intermodulation interference signal output by the receiving combining unit, the first intermodulation interference signal is obtained by the receiving combining unit combining a second intermodulation interference signal received from the radio frequency remote unit; The first processing unit outputs a second correction signal according to the first correction signal, the second correction signal is obtained by the first processing unit performing nonlinear cancellation on the first correction signal, and the second correction signal is used for subtraction or addition with the first intermodulation interference signal.

2. The method of claim 1, wherein, The method further comprises: The first processing unit receives an i-th first correction signal, the i-th first correction signal is obtained by adding or subtracting an (i-1)-th first intermodulation interference signal and an (i-1)-th second correction signal, i is a positive integer greater than 1; The first processing unit outputs an i-th second correction signal according to the i-th first correction signal, the i-th second correction signal is obtained by the first processing unit performing nonlinear cancellation on the i-th second correction signal.

3. The method of claim 1 or 2, wherein: The first processing unit sends indication information to the radio frequency remote unit, the indication information is used to indicate processing of a received signal, and the processing comprises linear cancellation or nonlinear cancellation of the received signal to obtain the second intermodulation interference signal.

4. A method of intermodulation correction applied to a distributed base station, characterized by, The distributed base station comprises a convergence unit and a radio frequency remote unit, the radio frequency remote unit comprises at least two modules, and the method comprises: The radio frequency remote unit receives indication information from the convergence unit, the indication information is used to indicate processing of a received signal; The radio frequency remote unit processes at least two received signals according to the indication information to obtain at least two second intermodulation interference signals, wherein each second intermodulation interference signal is obtained by processing one received signal by each module, the processing comprises linear intermodulation or nonlinear intermodulation, and the at least two second intermodulation interference signals can be processed by nonlinear cancellation by the first processing unit in the convergence unit; The radio frequency remote unit sends the at least two second intermodulation interference signals to the convergence unit.

5. An apparatus for intermodulation correction, characterized by The convergence unit comprises a first processing unit, a transmitting end, a receiving combining unit, The first processing unit is configured to receive a first correction signal, the first correction signal is a signal obtained by subtracting or adding a signal output by the first processing unit from a first intermodulation interference signal output by the receiving combining unit, the first intermodulation interference signal is obtained by the receiving combining unit combining a second intermodulation interference signal received from the radio frequency remote unit, and the second intermodulation interference signal is from different modules of the radio frequency remote unit. The first processing unit is further configured to output a second correction signal according to the first correction signal, the second correction signal being obtained by the first processing unit performing nonlinear cancellation on the first correction signal, and the second correction signal being used for being subtracted from or added to the first intermodulation interference signal.

6. The apparatus of claim 5, wherein, The first processing unit is further configured to receive an i-th first correction signal, the i-th first correction signal being obtained according to an (i-1)-th first intermodulation interference signal and an (i-1)-th second correction signal being added to or subtracted from each other, i being a positive integer greater than 1; The first processing unit is further configured to output an i-th second correction signal according to the i-th first correction signal, the i-th second correction signal being obtained by the first processing unit performing nonlinear cancellation on the i-th second correction signal.

7. The apparatus of claim 5 or 6, wherein, The first processing unit is further configured to send indication information to the radio remote unit, the indication information being used for indicating that the received signal is processed, and the processing includes linear cancellation or nonlinear cancellation on the received signal to obtain the second intermodulation interference signal.

8. An apparatus for intermodulation correction, characterized by The apparatus comprises a convergence unit and a radio remote unit, and the radio remote unit comprises at least two modules, The radio remote unit is configured to receive indication information from the convergence unit, the indication information being used for indicating that the received signal is processed; The radio remote unit is further configured to process at least two received signals according to the indication information to obtain at least two second intermodulation interference signals, wherein each second intermodulation interference signal is obtained by each module processing one received signal, and the processing includes linear intermodulation or nonlinear intermodulation, and the at least two second intermodulation interference signals can be processed by a first processing unit in the convergence unit through nonlinear cancellation; The radio remote unit is further configured to send the at least two second intermodulation interference signals to the convergence unit.

9. A communication system, characterized by The communication system comprises the apparatus of any one of claims 5 to 8.

10. A distributed base station, characterized by, The apparatus comprises: The apparatus of any one of claims 5 to 8 and a baseband unit.

11. An optical communication device, comprising: The apparatus comprises: A processor and a communication interface, the processor being coupled to a memory through the communication interface, and the processor being configured to execute program codes in the memory to implement the method of any one of claims 1 to 4.

12. A chip, characterized by The chip comprises programmable logic circuit and / or program instructions, and when the chip is running, the programmable logic circuit and / or program instructions are used to implement the method of any one of claims 1 to 4.

13. A computer-readable storage medium, characterized in that, The apparatus comprises: The computer readable storage medium stores a computer program, and when the computer program is running on the computer, the computer program causes the computer to execute the method of any one of claims 1 to 4.

14. A computer program product, characterised in that, The computer program product comprises a computer program or instructions, and when the computer program or instructions are running on the computer, the computer program or instructions cause the computer to execute the method of any one of claims 1 to 4.

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