PIM cancellation in a radio transceiver device

Abstract

There is provided techniques for PIM cancellation in a radio transceiver device. A method is performed by a PIM cancellation device. The method comprises obtaining traffic information from a baseband scheduler in the radio transceiver device. The traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals. The method comprises dynamically, and in accordance with the traffic information, updating a PIM model based on which the PIM cancellation in the radio transceiver device is performed. The method comprises performing PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

Description

[0001] PIM CANCELLATION IN A RADIO TRANSCEIVER DEVICE

[0002] TECHNICAL FIELD

[0003] Embodiments presented herein relate to a method, a passive intermodulation cancellation device, a computer program, and a computer program product for passive intermodulation cancellation in a radio transceiver device.

[0004] BACKGROUND

[0005] In general, radio communication systems might be subject to intermodulation distortion (IMD), which arises due to the inherent nonlinearity of radio frequency (RF) components. IMD occurs when signals of different frequencies pass through a nonlinear component, resulting in new and unwanted spectral components. Assuming and f2as the frequencies of two signals that pass through a nonlinear component, the general representation of the IMD signal components is given according to where fIMis the intermodulation (IM) product frequency, and n and m are integers. The absolute sum of these coefficients, i.e., |n| + |m|, is known as the order of the IM products. In the context of radio communications with modulated signals, the resulting bandwidth of the passive intermodulation components can be substantially large, and multiple higher-order IM products can be present at an intermodulation frequency. The frequency range of an IM product can be obtained as

[0006] RIM= |n|BWx+ |m|BW2where RIMis the range of the IM product, and BWXand BW2are the bandwidths of the fundamental signals. Fig. i illustrates the spectrum too of intermodulation distortion, where it can be observed that higher-order intermodulation distortion products may also appear at an intermodulation frequency, i.e., third-order IM frequency (f / M3) may contain, in addition to third-order IMD, also fifth-order IMD as well as other higher-order IMD. In Fig. 1, IM3 and IM5 refer to the third-order and the fifth-order intermodulation products, respectively. IM3 is calculated as 2f - f2and 2f2 and f2are the frequencies of the two original signals, whereas IM5 is calculated according combinations such as 3f - 2f2or 3f2— 2f , etc. While active RF components such as the power amplifiers (PAs) of a transmitting transceiver device and the low noise amplifiers (LNAs) of a receiving transceiver device are known to create IMD, passive components can also generate IMD. This is referred to as passive intermodulation (PIM). In general, any passive component along the RF signal transmission path, whether inside the radio transceiver device or in the vicinity of the radiating antenna, can cause PIM. Therefore, PIM sources can be classified as internal PIM sources (such as cable connectors, duplexers, attenuators, terminations, and antennas, etc.) and externa PIM sources that are located beyond the antenna. That is, external PIM originates from the surrounding environment and is often caused by nonlinearities in nearby metallic objects, such as billboards, metal fences, or any other metallic object that can reflect or scatter signals. For instance, a corroded metal object near an antenna can be excited by a high-power radio (radio) access network node transmitting signal and generating PIM which is reflected and couple into the receiver. This phenomenon is known as the Rusty Bolt Effect.

[0007] Fig. 2 is a block diagram of a multi-band multiple-input multiple-output (MIMO) frequency division duplexing (FDD) radio transceiver device 200, also illustrating some common sources of PIM. The MIMO radio transceiver device 200 comprises a radio unit 210 operatively connected to antennas 250 via diplexers 230, where the diplexers 230 are connected to the radio unit via radio ports 220, and where the diplexers 230 are connected to the antennas 250 unit via antenna ports 240. As schematically illustrated in the figure, there are three PIM sources; one external to (i.e., outside) the MIMO radio transceiver device 200 and two internal (i.e., caused by components within the MIMO radio transceiver device 200 itself). The external PIM source causes signals transmitted from the antennas 250 to be reflected back to the antenna ports 240.

[0008] Fig. 3(a) and Fig. 3(b) show spectrums 300a, 300b of PIM for a dual-band MIMO FDD radio transceiver device designed for operating on the frequency bands denoted NR N25 and N66. Fig. 3(a) represents an internal PIM scenario, where IM3 and IM5 are generated due to transmissions on the N25 frequency band in the downlink. This sometimes referred to as transmission line PIM, which occurs when downlink signals from the same antenna branch cause interference to the uplink frequency band of that particular antenna branch. Fig. 3 (b) represents an external PIM scenario, where IM3 and IM5 are generated due to transmission on the N25 and N66 frequency bands in the downlink. This occurs when downlink signals from the same or different antenna branches cause interference in an uplink frequency band of any antenna branch. This type of PIM is primarily caused by a PIM source located outside the radio transceiver device. For a scenario with internal PIM as shown in Fig. 3(a), the aggressors (i.e., the downlink signals) involved in the PIM generation in a PIM source only belong to a single band. It can be observed that the frequency band with small duplex distance, as in the case of the frequency band N25, suffers from internal PIM while PIM interference does not extend into the frequency band N66 due to large duplex distance between the uplink and downlink frequency bands. On the other hand, for a scenario with an external PIM source (i.e., with a PIM source located outside the radio transceiver device and is in the vicinity of the antenna) as shown in Fig. 3(b), the aggressor is defined by all transmit signals from all antennas. In this scenario, the transmitted signals from multiple frequency bands and multiple antenna branches will mix in an external PIM source, producing several spurious passive PIM terms that appear across multiple frequency bands used for the uplink.

[0009] For FDD transceivers where transmitter branches and receiver branches are sharing the same antenna by means of a duplexer, the bandpass filters in the duplexer can be tuned to protect the frequency bands used for the downlink and the frequency bands used for the uplink from each other. However, the PIM originating inside, or after the duplexer, are preserved on the frequency bands used for the uplink and appear together with the desired uplink signal in the receiver chains.

[0010] In general terms, the relative strength of the PIM depends on several factors, such as transmit power, traffic load, PIM source characteristics, PIM source location relative to the antenna (in case of an external PIM source), etc. On some occasions, the level of PIM can be several decibel (dB) stronger than the received uplink signal. Especially for power-limited transceivers in user equipment in poor coverage, PIM interference can completely mask the desired uplink signal and cause receiver desensitization.

[0011] There are various approaches to mitigate or reduce the impact of PIM. PIM mitigation techniques such as frequency band separation and frequency hopping, as applicable for narrowband communication systems, cannot totally mitigate PIM for wideband communication systems such as Wideband Code Division Multiple Access (WCDMA), Long-Term Evolution (LTE), LTE-Advanced, 5G New Radio, 5G- Advanced, and Beyond 5G communication systems.

[0012] In general terms, modeling and cancellation, or at least mitigation, of PIM in the digital domain can be achieved through polynomial modeling whose computational complexity often grows rapidly with an increased number of frequency bands and antenna branches. For reference, if six polynomial terms are needed to model a PIM in a single-band scenario with two antenna branches in the transmitter and one antenna branch in the receiver, then the number of terms grows to 40 polynomial terms for a single-band scenario with four antenna branches in the transmitter and one antenna branch in the receiver, and to 160 polynomial for a single-band scenario with four antenna branches in the transmitter and four antenna branches in the receiver. Similarly, the modeling complexity of a third-order order nonlinearity increases as 0(A3). Therefore, the computational complexity for PIM modeling and cancellation is often significant in multi-band MIMO radio transceiver devices.

[0013] Hence, there is still a need for improved PIM cancellation techniques.

[0014] SUMMARY

[0015] An object of embodiments herein is to provide efficient PIM cancellation that does not suffer from the above issues, or at least where the above issues have been mitigated or reduced.

[0016] Digital implementations for PIM cancellation aim to create a perfect interference model to potentially eliminate cancel the PIM, i.e., to suppress the PIM sufficiently below the receiver thermal noise floor. Since the modeling and cancellation of PIM is performed in time-domain, the PIM cancellation device utilizes its computational resources based on the frequency bands combination and the number of antenna ports. However, in practice, the PIM cancellation requirements can be different in different parts of the uplink spectrum. Not taking this into consideration might negatively affect the PIM cancellation capability, or result in unnecessary PIM cancellation being performed (which in turn might result in waste of energy consumption and power dissipation).

[0017] A particular object is therefore to provide PIM cancellation that can be different in different parts of the uplink spectrum. In case the PIM cancellation device fails to model the complete set of PIM sources and signal, the PIM cancellation device might be unable to determine which PIM sources to prioritize cancelling.

[0018] A particular object is therefore to provide PIM cancellation that can prioritize which PIM sources to cancel.

[0019] According to a first aspect there is presented a method for PIM cancellation in a radio transceiver device. The method is performed by a PIM cancellation device. The method comprises obtaining traffic information from a baseband scheduler in the radio transceiver device. The traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals. The method comprises dynamically, and in accordance with the traffic information, updating a PIM model based on which the PIM cancellation in the radio transceiver device is performed. The PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level. Distribution of the computational resources is determined in accordance with the obtained traffic information. The method comprises performing PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

[0020] According to a second aspect there is presented a PIM cancellation device for PIM cancellation in a radio transceiver device. The PIM cancellation device comprises processing circuitry. The processing circuitry is configured to cause the PIM cancellation device to obtain traffic information from a baseband scheduler in the radio transceiver device. The traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals. The processing circuitry is configured to cause the PIM cancellation device to dynamically, and in accordance with the traffic information, update a PIM model based on which the PIM cancellation in the radio transceiver device is performed. The PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level. Distribution of the computational resources is determined in accordance with the obtained traffic information. The processing circuitry is configured to cause the PIM cancellation device to perform PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

[0021] According to a third aspect there is presented a PIM cancellation device for PIM cancellation in a radio transceiver device. The PIM cancellation device comprises an obtain module configured to obtain traffic information from a baseband scheduler in the radio transceiver device. The traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals. The PIM cancellation device comprises an update module configured to dynamically, and in accordance with the traffic information, update a PIM model based on which the PIM cancellation in the radio transceiver device is performed. The PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level. Distribution of the computational resources is determined in accordance with the obtained traffic information. The PIM cancellation device comprises a cancel module configured to perform PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

[0022] According to a fourth aspect there is presented a computer program for PIM cancellation in a radio transceiver device. The computer program comprises computer code which, when run on processing circuitry of a PIM cancellation device, causes the PIM cancellation device to perform actions. One action comprises the PIM cancellation device to obtain traffic information from a baseband scheduler in the radio transceiver device. The traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals. One action comprises the PIM cancellation device to dynamically, and in accordance with the traffic information, update a PIM model based on which the PIM cancellation in the radio transceiver device is performed. The PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level. Distribution of the computational resources is determined in accordance with the obtained traffic information. One action comprises the PIM cancellation device to perform PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

[0023] According to a fifth aspect there is presented a computer program product comprising a computer program according to the fourth aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium.

[0024] Advantageously, these aspects provide PIM cancellation that does not suffer from the above issues.

[0025] Advantageously, these aspects enable the computational resources for PIM cancellation to be utilized for efficient modeling and cancellation of the PIM. This can improve the efficiency of the PIM cancellation, as well as provide observability improvements by demonstrating improved quality-of-service for uplink signals originating from radio transceiver devices that are power limited in the uplink or are affected more by the PIM interference than other radio transceiver devices.

[0026] Advantageously, these aspects enable the computational resources for PIM cancellation to be dynamically allocated, and even enables the PIM cancellation to be disabled if the traffic load decreases or the quality-of-service requirements for the uplink signals allows for this.

[0027] Advantageously, these aspects enable the PIM cancellation requirements to be relaxed for the uplink signals based on desired uplink signal-to-interference plus noise ratio requirements, thereby correspondingly reducing the power dissipation of the PIM cancellation device.

[0028] Advantageously, these aspects enable the PIM cancellation to be made dependent on the estimated or predicted downlink signal power.

[0029] Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, module, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

[0030] BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

[0032] Fig. 1 shows a spectrum of intermodulation distortion according to an example;

[0033] Fig. 2 shows common sources of PIM in a MIMO radio transceiver device according to an example;

[0034] Figs. 3(a) and 3(b) show spectral illustrations of PIM for a dual-band MIMO FDD radio transceiver device according to examples;

[0035] Fig. 4 provides a conceptual spectral illustration of uplink signals and PIM distortion according to an example;

[0036] Fig. 5 is a block diagram of a radio transceiver device according to an embodiment;

[0037] Figs. 6, 7, and 8 are block diagrams of PIM cancellation devices according to embodiments;

[0038] Fig. 9 is a flowchart of methods according to embodiments;

[0039] Figs, io, n, and 12 show simulation results according to embodiments;

[0040] Fig. 13 is a schematic diagram showing structural units of a PIM cancellation device according to an embodiment;

[0041] Fig. 14 is a schematic diagram showing functional modules of a PIM cancellation device according to an embodiment; and Fig. 15 shows one example of a computer program product comprising computer readable storage medium according to an embodiment.

[0042] DETAILED DESCRIPTION

[0043] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

[0044] As noted above, there is still a need for improved PIM cancellation techniques.

[0045] To address at least some of the above-mentioned limitations, according to at least some of the herein disclosed embodiments, there is disclosed techniques for dynamic allocation of PIM modeling and cancellation computational resources in a PIM cancellation device that optimizes the computational resource usage for enhanced energy efficiency whilst simultaneously ensuring that the information bits of intended uplink signal are effectively recovered. It is demonstrated through rigorous experiments that the PIM cancellation requirement can be different across uplink scheduled users due to their distance to the (radio) access network node receiver, and correspondingly their received signal strength, employed modulation technique, traffic load, as well as the channel characteristics. This information is nevertheless retrieved in the digital baseband unit, while PIM cancellation device often resides in the radio transceiver device. Through baseband scheduling-aware PIM cancellation, the computational resources in the PIM cancellation device can be optimized to either relax the cancellation requirements on certain frequency bins where uplink signal have strong received signal strength or lower modulation order, or more computational resources can be allocated for sophisticated modeling and enhanced cancellation on frequency bins where PIM is dominant. In addition, for instances where lower cancellation gain is required, the PIM cancellation device can disable some or all of its computational resources to save energy consumption. Alternatively, in case the PIM cancellation device has reconfigurable processing, the PIM cancellation device can allocate its computational resources to frequency bins accordingly.

[0046] In some embodiments, part of the interference is mitigated in time-domain within the radio transceiver device while the remaining interference is corrected in the frequency domain in the digital unit. Coordinated PIM cancellation between the digital unit (comprising the baseband unit) and radio transceiver devices can, for example, be applied in cases where lower order modulation does not require any PIM cancellation and where instead coding schemes and / or equalization schemes can be applied to compensate for both channel errors and PIM.

[0047] Legacy receiver algorithms can used for compensating for PIM interference to some extent without any PIM cancellation being performed in the baseband unit. As an example, interference rejection and combining (IRC) or maximum ratio combining (MRC) techniques can be applied to reduce the impact of interference and / or to enhance the received signal strength. In general terms, IRC relies on the fact that the interference is correlated between different antenna branches. In the context of PIM, specifically when the PIM source is external to the (radio) access network node, the PIM affects all antenna branches and thus acts as a correlated interference for the different antenna branches. Generally, the correlation strength of the PIM depends on the power of the PIM interference, the relative position of the PIM source to different antenna elements, the channel conditions, and the traffic load on each antenna port. Nevertheless, IRC can still be used to estimate and cancel part of the PIM interference.

[0048] Multiple antenna techniques can be used to enhance data rates and reliability. When both the transmitting transceiver device and the receiving transceiver device are equipped with multiple antennas, then such a communication system is referred to as MIMO system.

[0049] As an illustrative example, assume a scenario where user equipments (UEs) are communicating with a (radio) access network node in a wireless network, and where the (radio) access network node schedule the UEs on different parts of the spectrum and assigns the UEs different modulation and coding schemes. Depending on the distance of the UEs to the (radio) access network node, the received signal power from the UEs at the (radio) access network node can be different for different UEs. In some examples, the presence of IMD, for example due to a PIM source, may degrade the receiver sensitivity of the (radio) access network node as illustrated conceptually in the example of Fig. 4 which shows a conceptual spectral illustration 400 of uplink signals and PIM distortion and where there are two PIM sources.

[0050] In Fig. 5 is shown a block diagram of a multi-band MIMO FDD transceiver 500 according to an embodiment. The transceiver comprises transmitter chains (TX1 RC), receiver chains (RX1 RC), a duplexer unit to selectively couple the transmitter chains or the receiver chains to an antenna unit with multiple antennas, a diplexer (or combiner) to combine multiple transmitter chains or receiver chains for multiple frequency bands and map them to the antenna unit, digital to analog converters (DACs), analog to digital converters (ADCs), power amplifiers (PAs), low noise amplifiers (LNAs), and a PIM modeling and regeneration unit (represented by “PIM Model”) that injects a model of an undesired PIM distortion signal, as generated in a non-linear PIM regeneration (Regen.) block based on digital transmission (TX) data, into the receiver chains to suppress the level of PIM interference present in the uplink.

[0051] The FDD transceiver is a full-duplex transceiver i.e., it is configured for simultaneous transmission and reception of radio signals. The transmitter chains and the receiver chains operate at different radio frequencies, and the duplexer provides isolation to the receiver chains against high-power transmit signals.

[0052] PIM typically appears as a noise in the received signal spectrum and thus degrades the signal-to-noise ratio (SNR) of the uplink signal. For a UE (such as UE3 in Fig. 4) operating at the cell edge, the received strength signal at the receiver of the (radio) access network node for such a UE can be very weak and its reception can be completely blocked due to the presence of PIM interference. In other words, the decoding process of the receiver will fail due to the degraded SNR. In turn this can lead to significant throughput loss or complete failure of the communication link between the (radio) access network node and the affected UE. Therefore, reducing the PIM interference may enhance the receiver sensitivity, and is especially beneficial for power limited UEs. On the other hand, there can be other UEs that are located comparatively closer to the (radio) access network node, where the uplink received signals are much stronger than the PIM interference (for instance for UE2 in Fig. 4). For such UEs, the information bits can be recovered easily, although the PIM might degrade the quality of service. There can also be instances where the PIM, particularly higher-order PIM interference, is below the noise floor and does not cause any degradation.

[0053] Fig. 6 is a block diagram 600 of a PIM cancellation device 610 according to an embodiment for digital PIM cancellation. Generally, the PIM cancellation device comprises an estimator 620, or predictor, to compute PIM cancellation coefficients, and an actuator 630 to generate a replica signal of the PIM interference. In some examples, the PIM cancellation coefficients are computed by the estimator, or predictor, using a least-squares algorithm or some gradient-descent algorithm. The PIM cancellation coefficients are generally complex-valued and adjust the gain and phase of the intermodulation distortion signal. In some examples, the PIM cancellation coefficients are sent to a PIM cancellation actuator block configured to generate an intermodulation distortion signal (corresponding to the replica signal). In some examples, the intermodulation distortion signal is generated through nonlinear processing of the transmit signals to generate basis functions that model the PIM intermodulation products. In some examples, the PIM cancellation actuator taps the downlink transmit signals and process them in a nonlinearity basis function (BF) generator 640. The BF generator might for this purpose implement a Volterra model or any simplification thereof, such as Memory Polynomials (MPs), Generalized Memory Polynomials (GMPs), Look-up Tables (LUTs) or other nonlinear modeling structures. After generating the intermodulation signal which, in an ideal case, is an exact replica of the PIM interference in the uplink signal, a subtractor operator is implemented in the receiver to suppress the level of PIM in the received uplink signal.

[0054] In some examples, a PIM analyzer 660 is also complemented to the PIM cancellation device. The PIM analyzer can be configured to process the downlink carrier frequencies and inform a baseband scheduler 670 to configure downlink carrier frequencies such that PIM interference on specific uplink channels can be avoided.

[0055] Further, Fig. 6 illustrates a baseband scheduler 670 (also referred to as a MAC scheduler, where MAC is short for medium access control) configured to schedule both downlink signals and uplink signals and to assign frequency bands to the scheduled signal. The baseband scheduler determines the modulation and coding scheme for the scheduled signals and allocate physical layer computational resources, such as the number of subcarriers or primary computational resource blocks (PRBs), to the scheduled signals. This assignment is performed per each transmission time interval (TTI). This means that the profile of the PIM interference and its effect on the uplink channels may change per TTI. Since the traffic load varies across different users and is seldom ioo% in both uplink and downlink, this suggests that the actual PIM interference level can change as well. Further, the requirement on PIM cancellation can be different for different load conditions. Therefore, the deterministic downlink traffic load, known to the baseband scheduler for both the downlink and the uplink, can be utilized to adapt the capability of the PIM cancellation device.

[0056] The baseband scheduler might be configured to allocate different modulation and coding schemes to different UEs, depending on demands of data rates, and channel conditions. The changes in modulation and coding scheme might have consequences on the required PIM cancellation. This can be determined by the reference sensitivity level defined for each modulation scheme. According to some non-limiting examples, the modulation scheme is any of: quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), 16-QAM, 64-QAM, 256-QAM, etc. The baseband scheduler can determine the required signal-to-interference plus noise ratio (SINR) post PIM cancellation for different uplink users and report this to the PIM cancellation configuration function which can then allocate the PIM cancellation computational resources accordingly.

[0057] Fig. 7 is a block diagram 700 of a PIM cancellation device 710 according to an embodiment for PIM cancellation in a radio transceiver device. The PIM cancellation device of Fig. 7 incorporates all functionalities of the PIM cancellation device in Fig. 6 and thus comprises an estimator 720, or predictor, to compute PIM cancellation coefficients, an actuator 730 to generate a replica signal of the PIM interference, and a nonlinearity BF generator 740. In particular, in addition to implementing a PIM cancellation device configured to estimate, model, and regenerate the PIM signal, the PIM cancellation device in Fig. 7 comprises a PIM configuration unit 750 configured to analyze downlink and uplink signals and to configure the computational resources of the PIM cancellation actuator. This flexibility allows the nonlinear actuator to apply different models to different frequency bins and thereby to perform frequency- selective PIM cancellation. For instance, the actuator may decide to utilize more memory taps in the modeling for frequency bins that are at the frequency band edges as the PIM occurring in the frequency band edges night be more challenging to cancel due to high frequency selectivity of duplex bandpass filter response. Alternatively, more memory taps can be used for antenna branches that are affected by multiple PIM sources. Alternatively, higher-order nonlinear terms, such as third order and fifth-order intermodulation distortion, are modeled for specific uplink frequency bins where the PIM interference is stronger. Thus, the PIM cancellation device can thereby be configured to deploy different intermodulation order modeling in different frequency bins depending on the level of the PIM interference, i.e., the higher the level of PIM the more likely it is to have higher-order intermodulation.

[0058] The block diagram 700 further comprises a PIM analyzer 760 and a scheduler 770.

[0059] If the SINR of some or all uplink channels is good, then PIM cancellation may not be required. This might be the case for UE1 and UE2 in Fig. 4. The PIM configuration unit receives information from the baseband scheduler to configure, enable, or disable PIM actuator and PIM cancellation computational resources for intermodulation signal generation across frequency bins. The baseband scheduler can calculate the SINR and report it to the PIM cancellation configuration unit. The PIM cancellation actuator is configured to either increase or to reduce the PIM cancellation capability depending on the reported SINR. In some scenarios, the PIM cancellation device is configured to completely disable the PIM cancellation on certain frequency bins if the uplink QoS requirements are fulfilled even in the presence of PIM, i.e., where higher-order PIM is overlapping with a frequency bin but is sufficiently weak to not cause any performance degradation.

[0060] In some examples, the baseband scheduler 770 is configured to interact with functions in the digital unit to determine the target SINR for different users. For example, Interference Rejection and Combining (IRC) can be used to mitigate correlated interference in the uplink. For PIM interference originating outside the radio, interference in the uplink can also appear as a correlated interference and can be suppressed to a certain extent by using IRC. While the gain from IRC for PIM mitigation may be limited in remote radios with few antenna branches, such as 2 or 4 antenna branches, it may increase if the PIM is significantly stronger (appearing as more correlated among the antenna branches) or if the number of antenna branches increases. The baseband scheduler can then decide on how much IRC can cancel PIM without PIM cancellation and calculate the remaining SINR that is set as a target for the PIM cancellation device.

[0061] In some examples, the PIM cancellation device interact with multiple baseband schedulers to better optimize its computational resource usage. Each MAC schedular may associate a priority level with its request towards the PIM cancellation configuration unit, and the PIM cancellation device can then subdivide its computational resources based on this report. For instance, PIM cancellation in the uplink of a power limited UE at the cell-edge with heavily degraded SINR may be given a higher priority such that more PIM cancellation computational resources are allocated to achieve higher PIM cancellation for this UE to maintain its connection to the network.

[0062] In this way the computational resources of the PIM cancellation device can be optimized based on the detection accuracy of the information bits. As opposed to determining PIM cancellation performance in time domain in a radio transceiver device, the PIM cancellation device instead waits for a report from the digital unit and performs coordinated cancellation. Such an approach can eliminate the need of PIM cancellation on certain frequency bins or reduce the requirements of PIM cancellation gain, leading to PIM cancellation computational resource saving and thereby improved energy consumption. In addition, coordinated PIM cancellation can help to better allocate the computational resources for PIM cancellation to frequency bins that require higher PIM cancellation, which can then maximize the coverage and throughput of the radio system. Finally, for scenarios with frequency band combinations where PIM cancellation appears under-dimensioned, i.e., where the PIM cancellation device cannot model all the resulting nonlinear terms for PIM interference, the PIM cancellation device can be configured to prioritize the computational resources for PIM cancellation to the frequency channels with weak signals, or inform the baseband scheduler to adapt the traffic such that the impact of the PIM can be reduced. Although the PIM cancellation devices thus far has been described and depicted as being integrated in a radio transceiver device, other implementation options exist. As illustrated in the block diagram 8oo of Fig. 8, there can be a separate PIM cancellation device, placed in a PIM cancellation block 820 operatively connected between one or more baseband units 810 and a set of radio transceiver devices 830. The PIM cancellation device thereby has access to data signals being transmitted from multiple different radio transceiver devices, and thus capable of cancelling external PIM originating from transmissions from multiple radio transceiver devices. Fig. 8 also illustrates that there can be multiple baseband units (denoted “Baseband unit 1” and “Baseband unit 2” each having a downlink (DL) block and an uplink (UL) block controlled by a scheduler) sharing a common set of radio transceiver devices (denoted “Radio unit 1” and “Radio unit 2” each having a transmitter (TX) block and a receiver (RX) block), and that there can be PIM cancellation capabilities both in the separate PIM cancellation block and in the radio transceiver devices. The PIM cancellation device in each radio transceiver device could then be configured to cancel PIM originating from its own components, whilst the PIM cancellation device in the separate PIM cancellation block is configured to cancel PIM originating from a combination of the signals as transmitted from all radio transceiver devices. For example, Fig. 8 could represent a scenario where a first baseband unit (such as “Baseband unit 1”) is configured for 5G NR communication and a second baseband unit (such as “Baseband unit 2”) is configured for 4G LTE communication. 5G NR has carriers on both frequency band 1 (fiA) and frequency band 2 (f2) whereas 4G LTE is only using frequency band 1 (fiB).

[0063] In further example, the block diagram of Fig. 8 comprises at least two baseband units that share one single radio transceiver device. This one single radio transceiver device might be configured for both 5G NR and 4G LTE. Also in this case there could be a separate PIM cancellation block between the at least two baseband units and the radio transceiver device, where the PIM cancellation in the PIM cancellation block would receive information from the different schedulers in the baseband units and adapt its computational resources for performing the PIM cancellation accordingly.

[0064] Fig. 9 is a flowchart illustrating embodiments of methods for PIM cancellation in a radio transceiver device. The methods are performed by the PIM cancellation device. The methods are advantageously provided as computer programs 1520. S102: The PIM cancellation device obtains traffic information from a baseband scheduler in the radio transceiver device.

[0065] The traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device. The traffic information further pertains to information of uplink signals to be received by the radio transceiver device. The traffic information further pertains to a required quality level of the uplink signals.

[0066] S104: The PIM cancellation device dynamically, and in accordance with the traffic information, updates a PIM model based on which the PIM cancellation in the radio transceiver device is performed.

[0067] The PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level. The distribution of the computational resources is determined in accordance with the obtained traffic information.

[0068] S108: The PIM cancellation device performs PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

[0069] Embodiments relating to further details of PIM cancellation in a radio transceiver device as performed by the PIM cancellation device will now be disclosed with continued reference to Fig. 9.

[0070] As disclosed above, in some embodiments, the radio transceiver device uses FDD for transmitting the downlink signals and receiving the uplink signals.

[0071] In some aspects, the traffic information is obtained per TTI. The PIM model can then also be updated per TTI. Hence, one occurrence of steps S102-S108 can be performed per TTI. For a next TTI, step S102 can be entered once again, as indicated by the arrow from step S108 to step S102 in Fig. 9. In other words, in some embodiments, the traffic information is obtained, and the PIM model is updated, per TTI.

[0072] There could be different types of traffic information of the uplink signals. In some non-limiting examples, the traffic information of the uplink signals pertains to any, or any combination of: received signal strength, employed modulation and coding scheme, traffic load, uplink channel characteristics, signal-to-interference plus noise ratio post or prior to PIM cancellation. Based on this information, if the SINR of some or all uplink channels is good, then PIM cancellation may not be required at all, for example enabling PIM cancellation to be completely disabled on certain frequency bins.

[0073] In some aspects, the PIM cancellation device receives information from the baseband scheduler about any post-correction, such as IRC or MRC, being performed in the baseband. Therefore in, some embodiments, the traffic information further comprises information whether or not post-correction of the uplink signals is performed in baseband. The PIM cancellation device will then use this information when adapting the PIM cancellation in the radio transceiver device. For example, the PIM cancellation in the radio transceiver device might be less aggressive in case postcorrection is performed in the baseband since then, although the PIM cancellation in the radio transceiver device does not cancel all the PIM, the post-correction in the baseband will still improve the quality of the received uplink signals.

[0074] There could be different types of PIM models, such as a Volterra model or any simplification thereof, such as MPs, GMPs, LUTs, or other nonlinear modeling structures. As disclosed above, the PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level. There could be different computational resources for performing the PIM cancellation. In some non-limiting examples, the PIM model is of an adaptable model order, and the computational resources pertain to which model order the PIM model is to have. Here, the memory order could specify the number of taps used in the PIM model. Further in this respect, PIM cancellation is essentially creating a replica of the interference, and creation involves multiplying each nonlinear term with a filter (that has a memory). As described earlier, the number of nonlinear terms grows with the band combination and antenna elements. Now, the computational resources in a PIM cancellation unit can be defined as the number building blocks capable of generating nonlinear terms. For instance, each building block might output one, two, or three nonlinear terms. By adapting the model, these building blocks can be selectively enabled and disabled in order to nonlinear terms to be generated based on the requirements. There could be different ways for the PIM cancellation device to perform the PIM cancellation on the uplink signals in step Sio8. In some embodiments, the PIM cancellation device, based on the PIM model, regenerates a PIM signal and subtracts the regenerated signal from the uplink signals, as part of performing the PIM cancellation in step Sio8.

[0075] As disclosed above, in case the PIM cancellation device has reconfigurable processing, the PIM cancellation device can allocate its computational resources to frequency bins accordingly, and the nonlinear actuator can apply different models to different frequency bins and thereby to perform frequency-selective PIM cancellation. Therefore, in some embodiments, the uplink signals are to be received within a frequency interval that is divisible into frequency bins, and, according to the PIM model, different amounts of the computational resources for performing the PIM cancellation are allocated for the different frequency bins.

[0076] As further disclosed above, the actuator may decide to utilize more memory taps in the modeling for frequency bins that are at the frequency band edges as the PIM occurring in the frequency band edges night be more challenging to cancel due to high frequency selectivity of duplex bandpass filter response. Therefore, in some embodiments, according to the PIM model, more of the computational resources are allocated for performing the PIM cancellation in the frequency bins at the edges of the frequency interval than for performing the PIM cancellation in frequency bins in the center of the frequency interval.

[0077] As further disclosed above, more memory taps can be used for antenna branches that are affected by multiple PIM sources. Therefore, in some embodiments, according to the PIM model, the PIM is caused by at least three PIM sources, and more of the computational resources are allocated for performing the PIM cancellation in the frequency bins impacted by more than PIM source than for performing the PIM cancellation in frequency bins impacted by at most one PIM source.

[0078] As further disclosed above, higher-order nonlinear terms, such as third order and fifth-order intermodulation distortion, are modeled for specific uplink frequency bins where the PIM interference is stronger. Therefore, in some embodiments, according to the PIM model, the more a given frequency bin is impacted by the PIM, the more of the computational resources are allocated for performing the PIM cancellation in this given frequency bin.

[0079] As further disclosed above, the PIM cancellation device is configured to completely disable the PIM cancellation on certain frequency bins if the uplink QoS requirements are fulfilled even in the presence of PIM. Therefore, in some embodiments, according to the PIM model, none of the computational resources are allocated for performing the PIM cancellation in at least one of the frequency bins.

[0080] As further disclosed above, in case the PIM cancellation device cannot model all the resulting nonlinear terms for PIM interference, the PIM cancellation device might inform the baseband scheduler to adapt the traffic such that the impact of the PIM can be reduced. Therefore, in some embodiments, the PIM cancellation device is configured to perform (optional) step Sio6 when the required quality level of the uplink signals cannot be met by the PIM cancellation device.

[0081] Sio6: The PIM cancellation device requests the baseband scheduler to re-schedule reception of at least some of the uplink signals and / or to perform post-correction of the uplink signals in baseband.

[0082] Different implementation aspects of the PIM cancellation device will be disclosed next.

[0083] In some embodiments, the PIM cancellation device is part of the radio transceiver device. This is the case for the block diagrams in Fig. 6, Fig. 7, and for the PIM cancellation devices in the radio transceiver devices in Fig. 8.

[0084] In some embodiments, the baseband scheduler belongs to a set of at least two baseband schedulers, the radio transceiver device belongs to a set of at least one radio transceiver device, and the PIM cancellation device is operatively connected between the set of at least two baseband schedulers and the set of at least one radio transceiver device. This is the case for the PIM cancellation device in the PIM cancellation block in Fig. 8.

[0085] As disclosed, the PIM cancellation device in the PIM cancellation block might be capable of cancelling external PIM originating from transmissions from multiple radio transceiver devices. Therefore, in some embodiments, the PIM cancellation device implements a respective PIM model for each pair of baseband scheduler and radio transceiver device, and the PIM model for a first pair of baseband scheduler and radio transceiver device is updated based on traffic information obtained from a baseband scheduler of a second pair of baseband scheduler and radio transceiver device.

[0086] Each scheduler may associate a priority level with its request towards the PIM cancellation device, and the PIM cancellation device can then subdivide its resources based on this information. Hence, in some embodiments, the traffic information from each of the baseband schedulers comprises a PIM cancellation priority level, and the computational resources are distributed in accordance with the PIM cancellation priority levels of all the baseband schedulers.

[0087] Further simulation results will be disclosed next.

[0088] Fig. io shows the PIM cancellation performance when the uplink signal employs different modulation schemes by plotting the symbol error rate (SER) against the signal to interference (PIM) ratio. It can generally be observed that the PIM cancellation requirements can be different for different modulation schemes. For example, if a baseline SER of IO-2is assumed, then the PIM interference mitigation requirement are 6 dB, 12 dB, and 18 dB for QPSK, 16-QAM, and 64-QAM respectively. Alternatively, the PIM cancellation requirements can be relaxed by up to 12 dB on frequency channels where a UE is scheduled to use QPSK modulation compared to another UE using, for example, 64-QAM modulation. The PIM cancellation device is deployed in the radio transceiver device and operates in time domain. However, the information bits are recovered from the data in frequencydomain, and different modulation schemes may require different SINR levels. The modulation and coding scheme of the uplink is decided by the baseband scheduler and is signaled to the PIM cancellation device in the uplink scheduling grant. The same information can thus be sent to the radio for configuration of the PIM cancellation device to optimize PIM cancellation HW usage.

[0089] The digital PIM cancellation performance is shown in Fig. 11 and Fig. 12 for a dualband communication system using the frequency bands N25 and N66 and with one external PIM source. PIM cancellation is configured to be either enabled or disabled for each of these frequency bands. In Fig. n is shown a comparison between the PIM cancellation being enabled for all channels and the PIM cancellation being disabled for channels in the frequency interval 12-32 MHz.

[0090] Fig. 13 schematically illustrates, in terms of a number of structural units, the components of a PIM cancellation device 1300 according to an embodiment. Processing circuitry 1310 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1510 (as in Fig. 15), e.g. in the form of a storage medium 1330. The processing circuitry 1310 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

[0091] Particularly, the processing circuitry 1310 is configured to cause the PIM cancellation device 1300 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 1330 may store the set of operations, and the processing circuitry 1310 may be configured to retrieve the set of operations from the storage medium 1330 to cause the PIM cancellation device 1300 to perform the set of operations. The set of operations may be provided as a set of executable instructions.

[0092] Thus the processing circuitry 1310 is thereby arranged to execute methods as herein disclosed. The storage medium 1330 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. The PIM cancellation device 1300 may further comprise a communications (comm.) interface 1320 at least configured for communications with other entities, functions, nodes, and devices, such as one or more radio transceiver devices and one or more baseband schedulers. As such the communications interface 1320 may comprise one or more transmitters and receivers, comprising analogue and digital components. The processing circuitry 1310 controls the general operation of the PIM cancellation device 1300 e.g. by sending data and control signals to the communications interface 1320 and the storage medium 1330, by receiving data and reports from the communications interface 1320, and by retrieving data and instructions from the storage medium 1330. Other components, as well as the related functionality, of the PIM cancellation device 1300 are omitted in order not to obscure the concepts presented herein. Fig. 14 schematically illustrates, in terms of a number of functional modules, the components of a PIM cancellation device 1400 according to an embodiment. The PIM cancellation device 1400 of Fig. 14 comprises a number of functional modules; an obtain module 1410 configured to perform step S102, an update module 1420 configured to perform step S104, and a cancel module 1440 configured to perform step S108. The PIM cancellation device 1400 of Fig. 14 may further comprise a number of optional functional modules, such as a request module 1430 configured to perform step S106. In general terms, each functional module 1410:1440 may in one embodiment be implemented only in hardware and in another embodiment with the help of software, i.e., the latter embodiment having computer program instructions stored on the storage medium 1330 which when run on the processing circuitry makes the PIM cancellation device 1300 perform the corresponding steps mentioned above in conjunction with Fig 14. It should also be mentioned that even though the modules correspond to parts of a computer program, they do not need to be separate modules therein, but the way in which they are implemented in software is dependent on the programming language used. Preferably, one or more or all functional modules 1410:1440 may be implemented by the processing circuitry 1310, possibly in cooperation with the communications interface 1320 and / or the storage medium 1330. The processing circuitry 1310 may thus be configured to from the storage medium 1330 fetch instructions as provided by a functional module 1410:1440 and to execute these instructions, thereby performing any steps as disclosed herein.

[0093] The PIM cancellation device may be provided as a standalone device or as a part of at least one further device. For example, the PIM cancellation device maybe provided in a node of the radio access network or in a node of the core network. Alternatively, functionality of the PIM cancellation device may be distributed between at least two devices, or nodes. These at least two nodes, or devices, may either be part of the same network part (such as a radio access network or a core network) or may be spread between at least two such network parts. In general terms, instructions that are required to be performed in real time may be performed in a device, or node, operatively closer to the cell than instructions that are not required to be performed in real time. Thus, a first portion of the instructions performed by the PIM cancellation device may be executed in a first device, and a second portion of the of the instructions performed by the PIM cancellation device may be executed in a second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the PIM cancellation device may be executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a PIM cancellation device residing in a cloud computational environment. Therefore, although a single processing circuitry 1310 is illustrated in Fig. 13 the processing circuitry 1310 may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 1410:1440 of Fig. 14 and the computer program 1520 of Fig. 15.

[0094] Some (radio) access network architectures define network nodes (or gNBs) comprising multiple component parts or nodes: a central unit (CU), one or more distributed units (DUs), and one or more radio transceiver devices (RUs). The protocol layer stack of the network node is divided between the CU, the DUs and the RUs, with one or more lower layers of the stack implemented in the RUs, and one or more higher layers of the stack implemented in the CU and / or DUs. The CU is coupled to the DUs via a fronthaul higher layer split (HLS) network; the CU / DUs are connected to the RUs via a fronthaul lower-layer split (LLS) network. The DU may be combined with the CU in some embodiments, where a combined DU / CU may be referred to as a CU or simply a baseband unit. A communication link for communication of user data messages or packets between the RU and the baseband unit, CU, or DU is referred to as a fronthaul network or interface. Messages or packets may be transmitted from the network node in the downlink (i.e., from the CU to the RU) or received by the network node in the uplink (i.e., from the RU to the CU).

[0095] Fig. 15 shows one example of a computer program product 1510 comprising computer readable storage medium 1530. On this computer readable storage medium 1530, a computer program 1520 can be stored, which computer program 1520 can cause the processing circuitry 1310 and thereto operatively coupled entities and devices, such as the communications interface 1320 and the storage medium 1330, to execute methods according to embodiments described herein. The computer program 1520 and / or computer program product 1510 may thus provide means for performing any steps as herein disclosed. In the example of Fig. 15, the computer program product 1510 is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 1510 could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 1520 is here schematically shown as a track on the depicted optical disk, the computer program 1520 can be stored in any way which is suitable for the computer program product 1510.

[0096] The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.

Claims

CLAIMS1. A method for passive intermodulation, PIM, cancellation in a radio transceiver device (500), wherein the method is performed by a PIM cancellation device (610, 710, 820, 1300, 1400), and wherein the method comprises: obtaining (S102) traffic information from a baseband scheduler (670, 870) in the radio transceiver device, wherein the traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals; dynamically, and in accordance with the traffic information, updating (S104) a PIM model based on which the PIM cancellation in the radio transceiver device is performed, wherein the PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level, and wherein distribution of the computational resources is determined in accordance with the obtained traffic information; and performing (S108) PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

2. The method according to claim 1, wherein the traffic information of the uplink signals pertains to any, or any combination of: received signal strength, employed modulation and coding scheme, traffic load, uplink channel characteristics, signal-to- interference plus noise ratio post or prior to PIM cancellation.

3. The method according to claim 1 or 2, wherein the traffic information further comprises information whether or not post-correction of the uplink signals is performed in baseband.

4. The method according to any preceding claim, wherein the PIM model is of an adaptable model order, and wherein the computational resources pertain to which model order the PIM model is to have.

5. The method according to any preceding claim, wherein performing the PIM cancellation comprises regenerating a PIM signal based on the PIM model, and subtracting the regenerated signal from the uplink signals.

6. The method according to any preceding claim, wherein the uplink signals are to be received within a frequency interval that is divisible into frequency bins, and wherein, according to the PIM model, different amounts of the computational resources for performing the PIM cancellation are allocated for the different frequency bins.

7. The method according to claim 6, wherein, according to the PIM model, more of the computational resources are allocated for performing the PIM cancellation in the frequency bins at edges of the frequency interval than for performing the PIM cancellation in frequency bins in a center of the frequency interval.

8. The method according to claim 6, wherein, according to the PIM model, the PIM is caused by at least three PIM sources, and wherein more of the computational resources are allocated for performing the PIM cancellation in the frequency bins impacted by more than PIM source than for performing the PIM cancellation in frequency bins impacted by at most one PIM source.

9. The method according to claim 6, wherein, according to the PIM model, the more a given frequency bin is impacted by the PIM, the more of the computational resources are allocated for performing the PIM cancellation in said given frequency bin.

10. The method according to claim 6, wherein, according to the PIM model, none of the computational resources are allocated for performing the PIM cancellation in at least one of the frequency bins.

11. The method according to any preceding claim, wherein the method further comprises, when the required quality level of the uplink signals cannot be met by the PIM cancellation device: requesting (S106) the baseband scheduler to re-schedule reception of at least some of the uplink signals and / or to perform post-correction of the uplink signals in baseband.

12. The method according to any preceding claim, wherein the PIM cancellation device is part of the radio transceiver device.

13. The method according to any preceding claim, wherein the baseband scheduler belongs to a set of at least two baseband schedulers, wherein the radio transceiver device belongs to a set of at least one radio transceiver device, and wherein the PIM cancellation device is operatively connected between the set of at least two baseband schedulers and the set of at least one radio transceiver device.

14. The method according to claim 13, wherein the PIM cancellation device implements a respective PIM model for each pair of baseband scheduler and radio transceiver device, and wherein the PIM model for a first pair of baseband scheduler and radio transceiver device is updated based on traffic information obtained from a baseband scheduler of a second pair of baseband scheduler and radio transceiver device.

15. The method according to claim 13 or 14, wherein the traffic information from each of the baseband schedulers comprises a PIM cancellation priority level, and wherein the computational resources are distributed in accordance with the PIM cancellation priority levels of all the baseband schedulers.

16. The method according to any preceding claim, wherein the radio transceiver device uses frequency division duplexing, FDD, for transmitting the downlink signals and receiving the uplink signals.

17. The method according to any preceding claim, wherein the traffic information is obtained, and the PIM model is updated, per transmission time interval, TTI.

18. A passive intermodulation, PIM, cancellation device (1300) for PIM cancellation in a radio transceiver device (500), the PIM cancellation device (1300) comprising processing circuitry (1310), the processing circuitry being configured to cause the PIM cancellation device (1300) to: obtain traffic information from a baseband scheduler (670, 870) in the radio transceiver device, wherein the traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to informationof uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals; dynamically, and in accordance with the traffic information, update a PIM model based on which the PIM cancellation in the radio transceiver device is performed, wherein the PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level, and wherein distribution of the computational resources is determined in accordance with the obtained traffic information; and perform PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

19. A passive intermodulation, PIM, cancellation device (1400) for PIM cancellation in a radio transceiver device (500), the PIM cancellation device (1400) comprising: an obtain module (1410) configured to obtain traffic information from a baseband scheduler (670, 870) in the radio transceiver device, wherein the traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals; an update module (1420) configured to dynamically, and in accordance with the traffic information, update a PIM model based on which the PIM cancellation in the radio transceiver device is performed, wherein the PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level, and wherein distribution of the computational resources is determined in accordance with the obtained traffic information; and a cancel module (1440) configured to perform PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

20. The PIM cancellation device (1300, 1400) according to claim 18 or 19, further being configured to perform the method according to any of claims 2 to 17.

21. A computer program (1520) for passive intermodulation, PIM, cancellation in a radio transceiver device (500), the computer program comprising computer code which, when run on processing circuitry (1310) of a PIM cancellation device (1300), causes the PIM cancellation device (1300) to: obtain (S102) traffic information from a baseband scheduler (670, 870) in the radio transceiver device, wherein the traffic information pertains to information of downlink signals to be transmitted by the radio transceiver device and to information of uplink signals to be received by the radio transceiver device and to a required quality level of the uplink signals; dynamically, and in accordance with the traffic information, update (S104) a PIM model based on which the PIM cancellation in the radio transceiver device is performed, wherein the PIM model defines how computational resources for performing the PIM cancellation are distributed for the required quality level, and wherein distribution of the computational resources is determined in accordance with the obtained traffic information; and perform (S108) PIM cancellation on the uplink signals as received by the radio transceiver device and in accordance with the dynamically updated PIM model.

22. A computer program product (1510) comprising a computer program (1520) according to claim 21, and a computer readable storage medium (1530) on which the computer program is stored.

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