Wireless system and method for measuring downlink passive intermodulation steering vectors

Abstract

Embodiment of present disclosure provides wireless system 200 and a method 400 for measuring DL RIM steering vectors for a wireless transceiver 202. The wireless system 200 radiates incident electric field on each antenna port to illuminate RIM reflector 206. The wireless system 200 performs scanning of each radiated antenna port to measure UL power value for each DL transmission. Further, the wireless system 200 computes UL, power value for each DL transmission from one or more radiated antenna ports 210. Thereafter, the wireless system 200 reconstructs DL RIM steering vector for at least one antenna port 210 to reduce the RIM excitation using the reconstructed DL RIM steering vectors.

Description

[0001] WIRELESS SYSTEM AND METHOD FOR MEASURING DOWNLINK PASSIVE INTERMODULATION STEERING VECTORS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications and in particular, to downlink passive intermodulation steering vector measurements more particularly, it relates to measuring downlink passive intermodulation steering vectors for a wireless transceiver.

[0004] BACKGROUND

[0005] Frequency-division duplexing, FDD, is a technique for establishing a full-duplex communication link that uses two different radio frequencies for each of a transmitter and a receiver operation. For instance, in mobile wireless networks, one block of a spectrum is allocated for uplink transmission, while another block of the spectrum is allocated for downlink transmission. The block allocated for uplink transmission carries data from mobile phones to a base station. The block allocated for downlink transmission carries data from the base station to the mobile phones.

[0006] Currently Signal-to-Noise Ratio SNR in an Uplink, UL, transmission of an FDD Advanced Antenna System AAS or any Radio Unit, RU, that is collocated at the cellular site, may be heavily impacted due to interferences that may be picked up from Passive Intermodulation, PIM, reflectors that are present around a region of the radio equipment or a wireless transceiver, such as RU or Digital Unit , DU, during Downlink, DL, transmissions in the wireless communication network.

[0007] Particularly, the PIM may occur by exciting the reflectors having non-linear property with two or more downlink carrier components. Moreover, the PIM that results from the non-linear property of the reflectors may lie in the UL frequency band when the UL transmission takes place. In order to mitigate such PIM interferences, one or more existing techniques may be performed during the DL transmission. The one or more existing techniques may include performing beamforming and / or null steering to minimize illumination of PIM sources to significantly decrease the interfering reflections generated by the PIM sources in the downlink, DL transmission. The PIM sources may include different types of passive components such as a rusty metals, loose mechanical contacts, any metallic structures that can pick-up and re-radiate electro-magnetic energy, and the like.

[0008] SUMMARY

[0009] Existing DL PIM spatial avoidance techniques currently mitigate the passive Inter-modulation, PIM, interferences by estimating a DL PIM steering vector Particularly, the DL PIM steering vector is obtained by using a covariance matrix of the UL received signal and then applying an eigen-value decomposition on the covariance matrix. That eigen-vector which corresponds to a dominant eigen-value corresponds to the UL PIM steering vector. Thereafter, a frequency translation technique, based on approximate far-field models, is applied by the one or more existing techniques to obtain the DL PIM steering vector.

[0010] However, the aforementioned approach of estimating the PIM interferences may not be consistently accurate and may yield erroneous results especially if the PIM sources are in the near-field of the wireless transceiver in the wireless communication network.

[0011] Hence, there is a need for an improved method for estimating / measuring the DL PIM steering vector that are used for PIM null steering in at least one Wireless Transceiver, WT. The proposed method thus, reduces the PIM interference measured in the UL during the DL transmission.

[0012] It is therefore an object of the present disclosure to provide a wireless system and a method for measuring DL PIM steering vectors for at least one WT, where all or at least some of the above-discussed drawbacks of presently known solutions are reduced, mitigated, or eliminated.

[0013] This and other objects are achieved by means of a wireless system and a method defined in the appended claims. The term exemplary is in the present context to be understood as serving as an instance, example or illustration.

[0014] According to a first aspect of the present disclosure, a wireless system is provided. The wireless system measures Downlink, DL, PIM, steering vectors for at least one wireless transceiver. The at least one wireless transceiver having a plurality of antenna ports. The wireless system comprises at least one signal injection module arranged for radiating an incident electric field on each antenna port from the plurality of antenna ports to illuminate at least one PIM reflector from a plurality of PIM reflectors arranged in a surrounding environment of the plurality of antenna ports. The wireless system performing scanning of each radiated antenna port from a plurality of radiated antenna ports to measure an uplink, UL, power value for each DL transmissions from a plurality of DL transmissions, from one or more radiated antenna port of the plurality of radiated antenna ports. The uplink power is generated due to the illumination of the at least one PIM reflector. The wireless system comprises at least one uplink power measurement module arranged for computing an Uplink, UL, power value for each DL transmission from one or more radiated antenna port. The wireless system comprises at least one control module in communication with each of: the at least one signal injection module and the at least one uplink power measurement module. The at least one control module is arranged for reconstructing at least one DL PIM steering vector for at least one antenna port from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission.

[0015] Optionally, the radiation of the incident electric field on each antenna port and the scanning of each DL transmission is performed in one or more steps from a plurality of steps for one or more antenna polarization.

[0016] Optionally, the scanning is Passive Intermodulation, PIM scanning, performed after performance of each step of the one or more steps of radiation of the incident electric field on each antenna port.

[0017] Optionally, the at least one control module is arranged for coordinating each step from the one or more steps of: performance of the radiation of the incident electric field on each antenna port and measurement of the UL power value for each DL transmission.

[0018] Optionally, the at least one uplink power measurement module is arranged for identifying a beam index for at least one beam from a plurality of beams for each DL transmission producing a maximum PIM excitation. The maximum PIM excitation is identified according to measurement of a UL power value for each beam from the plurality of beams. The at least one beam producing the maximum PIM excitation is having a maximum UL power value compared to UL power value of other beams from the plurality of beams. The at least one beam producing the maximum PIM excitations lies in an aggressor carrier of the at least one antenna port from the plurality of antenna ports. Optionally, the at least one signal injection module arranged for radiating in one of the aggressor carrier component in the at least one antenna port, the at least one beam from the plurality of beams producing the maximum PIM excitation through the incident electric field. The at least one beam from the plurality of beams producing the maximum PIM excitation is radiated for measurement of the uplink power value according to the maximum PIM excitation, along with other DL transmissions from the plurality of antenna ports in one or more other aggressor carrier component.

[0019] Optionally, the at least one signal injection module arranged for sequentially exciting one or more DL antenna ports through a sequential radiation of the incident electric field at a measurement period in one or more of aggressor carrier component arranged in at least one antenna port. The at least one signal injection module arranged for scanning each DL transmission of each radiated antenna port of the one or more radiated antenna ports after each sequential radiation. Further, the at least one uplink power measurement module is arranged for measuring the uplink power for each DL transmission of each antenna port after each scanning to identify a dominant DL antenna port index for at least one radiated antenna port producing a maximum PIM excitation from the one or more radiated antenna ports.

[0020] Optionally, the at least one signal injection module arranged for exciting the at least one DL dominant port through the radiation of the incident electric field along with one or more other antenna ports from a plurality of antenna ports in the plurality of antenna ports. The one or more other antenna ports are selected in a sequence for the excitation. The one or more other antenna ports are excited based on an application of one or more relative phase shifts with respect to the at least one dominant port. Further, the at least one uplink power measurement module is arranged for measuring, the uplink power value for each antenna port during each relative phase shift from the one or more relative phase shifts. The at least one uplink power measurement module is arranged for identifying at least one relative phase offset value from values of the one or more relative phase shifts that produces the maximum PIM excitation through the at least one other antenna port from the one or more other antenna ports during the radiation. The maximum PIM excitation corresponds to the maximum power value of the at least one other antenna port.

[0021] Optionally, the relative phase offset is varied between 0 to 360 degrees. Optionally, the at least one signal injection module arranged for exciting at least one first dominant antenna port along with the one or more other antenna ports from the plurality of other antenna ports. The one or more other antenna ports are selected in a sequence. The one or more other antenna ports are excited based on an application of a relative phase shift value with respect to the at least one dominant antenna port that maximizes the uplink PIM power for at least one other antenna port from the one or more other antenna ports. The one or more other antenna ports are excited by varying a value of an amplitude of a scaling factor. The at least one UL power measurement module arranged for performing uplink power measurement for each other antenna port from the one or more other antenna ports for each amplitude scaling factor to identify a scaling factor that produces a maximum PIM excitation.

[0022] Optionally, the value of the amplitude in the amplitude scaling factor is varied in a range of 0 to 1.

[0023] Optionally, a total downlink power corresponding to a sum of downlink power of each antenna port for each value of the amplitude is held constantfordifferent values of amplitude scaling factors.

[0024] Optionally, the at least one control module is arranged for reconstructing the at least one DL PIM steering vector from a plurality of DL PIM steering vectors for the at least one reflector according to each of the value of the relative phase offset and the value of the amplitude scaling factors that maximize the PIM excitation for different DL antenna ports from the plurality of antenna ports. The at least one DL PIM steering vector is reconstructed according to the performance of the one or more steps of the radiation of the incident electric field on each antenna port (210) and measurement of the UL power value for each DL transmission.

[0025] Optionally, the at least one signal injection module is arranged in one wireless transceiver in a plurality of wireless transceivers and wherein the at least one uplink power measurement module is arranged in other wireless transceiver in the plurality of wireless transceivers.

[0026] Optionally, the PIM source is located inside the wireless transceiver such as an inline PIM source. According to a second aspect of the present disclosure, a computer implemented method performed in a wireless system arranged for measuring Downlink, DL, Passive Intermodulation, PIM, steering vectors, for at least one wireless transceiver having a plurality of antenna ports is provided. The method comprises radiating, through an at least one signal injection module, an incident electric field on each antenna port from the plurality of antenna ports to illuminate at least one PIM reflector from a plurality of PIM reflectors arranged in a surrounding environment of the plurality of antenna ports. The method comprises performing scanning, through the at least one signal injection module of each radiated antenna port from a plurality of radiated antenna ports to measure an uplink, UL, power value for each DL transmissions from one or more radiated antenna port of the plurality of radiated antenna ports. The uplink power is generated due to the illumination of the at least one PIM reflector. The method comprises computing, through at least one uplink power measurement module an Uplink, UL, power value for each DL transmission from one or more radiated antenna port. The method comprises reconstructing, through at least one control module in communication with each of: the at least one signal injection module and at least one uplink power measurement module. The at least one DL PIM steering vector for at least one antenna port from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission.

[0027] According to a third aspect of the present disclosure, there is provided a computer program product comprising a non-transitory computer readable medium, having thereon a computer program comprising program instructions. The computer program is loadable into a data processing unit and configured to cause execution of the method according to the first and second aspects when the computer program is run by the data processing unit.

[0028] Some embodiments disclosed herein have one or more of the following advantages:

[0029] - Adaptiveness and robustness in estimatingthe DL PIM steering vectortothereby reduce the PIM inference measured in the UL during the DL transmission.

[0030] - Capable of being implemented in any radio equipment regardless of

[0031] • operating frequency,

[0032] • a UL-to-DL frequency gap,

[0033] • antenna array geometry, • whether the PIM sources are in the near-field or the far-field of the radio equipment.

[0034] - The proposed method and the wireless system does not rely on precomputed radiation patterns targeted for specific frequencies or does not rely on frequencies translation for far-field models.

[0035] - The proposed method and the wireless system allows for providing PIM measurements in a scenario where one radio equipment that is creating the interference during downlink transmission, i.e., a DL aggressor and another radio equipment facing the inference during uplink transmission, i.e., a UL victim are present on different radio equipment at the cellular site.

[0036] Other advantages may be readily apparent to one having skill in the art. Certain embodiments may have none, some, or all of the recited advantages.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The foregoing description will be apparent from the following more particular description of the example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments.

[0039] Fig. 1 discloses a wireless communication system according to some examples;

[0040] Fig. 2 shows a schematic diagram of the wireless communication system, according to an embodiment;

[0041] Figs. 3-A and 3-B shows some schematic block diagrams illustrating some example wireless system for measuring DL Passive Intermodulation, PIM measurements for at least one Wireless Transceiver, WT, according to some embodiments;

[0042] Fig. 4 is a flowchart illustrating example steps for a method for measuring DL PIM steering vectors according to some embodiments; and

[0043] Fig. 5 discloses an example computing environment according to some embodiments.

[0044] DETAILED DESCRIPTION Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The apparatus and methods disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

[0045] The terminology used herein is for the purpose of describing particular aspects of the disclosure only and is not intended to limit the invention. It should be emphasized that the term "comprises / comprising" when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0046] Embodiments of the present disclosure will be described and exemplified more fully hereinafter with reference to the accompanying drawings. The solutions disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0047] It will be appreciated that when the present disclosure is described in terms of a platform and a method, it may also be embodied in one or more processors and one or more memories coupled to the one or more processors, wherein the one or more memories store one or more programs that perform the steps, services and functions disclosed herein when executed by the one or more processors.

[0048] Fig. 1 discloses an example wireless communication system 100. Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in related to a wireless communication system / wireless network, such as the example wireless communication system 100 described in Fig. 1.

[0049] The wireless communication system 100 may comprise and / or interface with any type of communication, telecommunication, data, cellular, and / or radio network or other similar type of system. The wireless communication system 100 may be configured to operate according to specific standards or other types of predefined rules of procedures. Thus, the wireless communication system 100 may implement communication standards, such as, but are not limited to, global system for mobile communications, GSM, universal mobile telecommunications system, UMTS, long term evolution, LTE, and / or other suitable 2G, 3G, 4G, or 5G standards, wireless local area network, WLAN, standards such as, IEEE 802.11 standards, and / or any other appropriate wireless communication standards, such as, worldwide interoperability for microwave access, WiMax, Bluetooth, Z-Wave and / or ZigBee standards.

[0050] For simplicity, as depicted in Fig. 1, the wireless communication system 100 comprises a wireless system 200, a network node 104, and a network 106. The wireless system 200 and the network node 104 operate together in order to provide wireless connections in the wireless communication system 100. The network 106 may comprise one or more backhaul networks, core networks, IP networks, public switched telephone networks, PSTNs, packet data networks, optical networks, wide-area networks, WANs, local area networks, LANs, wireless local area networks, WLANs, wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between devices (for example, wireless devices and network node).

[0051] The network node 104 may refer to equipment capable, configured, arranged, and / or operable to communicate directly or indirectly with the wireless system 200 and / or with other network nodes or equipment in the wireless communication system 100 to enable and / or provide wireless access to the wireless system 200 and / or to perform other functions (for example, administration) in the wireless communication system 100. Examples of the network node 104 may include, but are not limited to, access points, APs (for example, radio access points), base stations, BSs (for example, radio base stations, nodeBs, evolved NodeBs, eNBs, new radio, NR, nodes (gNBs), or the like). The BSs may be categorized based on an amount of coverage the BSs provide (or, stated different, their transmit power level) and may then also be referred to as femto BSs, pico BSs, micro BSs, macro BSs. The BS may be a relay node or a relay donor node controlling a relay.

[0052] The wireless system 200 may refer to a device capable, configured, arranged and / or operable to communicate wirelessly with the network node 104 and / or other wireless devices. In some examples, the wireless system 200 may include one or more of: computing devices, wireless devices, ultra-low power wireless devices, Internet of Things, loT, devices, and so on.

[0053] Examples of the computing devices may include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over Internet Protocol, IP, VoIP, phone, a wireless local loop phone, a desktop computer, a personal digital assistant, PDA, a wireless camera, a gaming console or device, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment, LEE, a laptop-mounted equipment, LME, a smart device, a wireless customer-premise equipment, CPE, a vehicle- mounted wireless terminal device, and so on.

[0054] It should be understood that the wireless system 200 may not be limited to the abovedescribed wireless devices. The wireless system 200 may be extended to other wireless devices of different classes or categories providing different services while supporting, for example, Enhanced Mobile Broadband, eMBB, massive Machine-Type Communication, MTC, Ultra-Reliable Low Latency Communication, URLLC, Time Sensitive Networking, TSN, or the like.

[0055] In the wireless communication system 100, the network node 104 and the wireless system 200 are connected through 3GPP 5G core network where specific network services and operations are provided through software components called network functions (NFs). The wireless communication system 100 hosts large scale applications.

[0056] The one or more existing techniques are utilised in estimating the DL PIM steering vector for mitigating the PIM interference that occurs in the UL transmission due to the non-linear reflectors that are present in vicinity of the radio equipment during DL transmissions. However, the issue with the one or more existing techniques is that it is not consistently accurate and may yield erroneous results especially if the passive Intermodulation, PIM, source is in the near-field of the radio equipment in the wireless communication network.

[0057] Thus, the present disclosure enables the wireless communication network 100, the network node 104 and the wireless system 200 to measure DL PIM steering vectors for at least one Wireless Transceiver, WT, to minimize illumination of PIM sources for reducing the PIM interference occurring in the UL transmission due to one or more non-linear reflectors. Fig. 2 shows a schematic diagram of the wireless communication system 100, according to an embodiment. The wireless communication system 100, such as a 3rdGeneration Partnership Project, 3GPP-type cellular network that may support standards such as Long-Term Evolution, LTE, and / or New Radio, NR, 5G, comprises an access network 110, such as a radio access network, and a core network 114. The access network 110 comprises a plurality of network nodes 104a, 104b, 104c, i.e., referred collectively as network nodes 104, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 112a, 112b, 112c, i.e., referred collectively as coverage areas 112. Each network node 104a, 104b, 104c is connectable to the core network 114 over a wired or wireless connection 116. A first Wireless Device, WD, 118a located in coverage area 112a is configured to wirelessly connect to, or be paged by, the corresponding network node 104a. A second WD 118b in coverage area 112b is wirelessly connectable to the corresponding network node 104b. While a plurality of WDs 118a, 118b, i.e., collectively referred to as wireless devices 118, are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 104. Note that although only two WDs 118 and three network nodes 104 are shown for convenience, the communication system 100 may include many more WDs 118 and network nodes 104.

[0058] Also, it is contemplated that a WD 118 can be in simultaneous communication and / or configured to separately communicate with more than one network node 104 and more than one type of network node 104. For example, a WD 118 can have dual connectivity with a network node 104 that supports LTE and the same or a different network node 104 that supports NR. As an example, WD 118 can be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN. A network node 104, i.e., eNB or gNB, is configured to include a wireless system 200 which is configured to measure DL PIM steering vectors.

[0059] Fig. 3-A is a schematic block diagram illustrating an example wireless system 200 for measuring DL passive Intermodulation, PIM measurements for at least one Wireless Transceiver, WT, 202. The wireless system 200 comprises the at least one WT 202 having a plurality of antenna ports 210. For example, port 1, port 2... port n as shown in Fig. 3-A. The wireless system 200 comprises at least one signal injection module 204 arranged for radiating an incident electric field on each antenna port 210, i.e., the port 1, port 2... port n, from the plurality of antenna ports 210 to illuminate at least one PIM reflector 206 from a plurality of PIM reflectors 206 arranged in a surrounding environment of the plurality of antenna ports 210. Further, the at least one signal injection module 204 is arranged for performing scanning of each radiated antenna port 210 from a plurality of radiated antenna ports 210 to measure an uplink, UL, power value for each DL transmissions from a plurality of DL transmissions, from one or more radiated antenna port 210 of the plurality of radiated antenna ports 210. The uplink power is generated due to the illumination of the at least one PIM reflector 206.

[0060] The wireless system 200 comprises at least one uplink power measurement module 208 arranged for computing an Uplink, UL, power value for each DL transmission from one or more radiated antenna port 210. The wireless system 200 comprises at least one control module 212 in communication with each of the at least one signal injection module 204 and the at least one uplink power measurement module 208. The at least one control module 212 is arranged for reconstructing at least one DL PIM steering vector for at least one antenna port 210 from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission.

[0061] Optionally, the radiation of the incident electric field on each antenna port 210 and the scanning of each DL transmission is performed in one or more steps from a plurality of steps for one or more antenna polarization.

[0062] Optionally, the scanning is Passive Intermodulation, PIM scanning, performed after performance of each step of the one or more steps of radiation of the incident electric field on each antenna port 210.

[0063] Optionally, the at least one control module 212 is arranged for coordinating each step from the one or more steps of: performance of the radiation of the incident electric field on each antenna port 210 and measurement of the UL power value for each DL transmission.

[0064] Optionally, the at least one uplink power measurement module 208 is arranged for identifying a beam index for at least one beam from a plurality of beams for each DL transmission producing a maximum PIM excitation. For example, the beam is a multiple port coherently radiating to form a radiation pattern. The maximum PIM excitation is identified according to measurement of a UL power value for each beam from the plurality of beams. The at least one beam producing the maximum PIM excitation is having a maximum UL power value compared to UL power value of other beams from the plurality of beams. The at least one beam producing the maximum PIM excitations lies in an aggressor carrier of the at least one antenna port 210 from the plurality of antenna ports 210.

[0065] Optionally, the at least one signal injection module 204 arranged for radiating in one of the aggressor carrier component in the at least one antenna port 210, the at least one beam from the plurality of beams producing the maximum PIM excitation through the incident electric field. The at least one beam from the plurality of beams producing the maximum PIM excitation is radiated for measurement of the uplink power value according to the maximum PIM excitation, along with other DL transmissions from the plurality of antenna ports 210 in one or more other aggressor carrier component.

[0066] Optionally, the at least one signal injection module 204 arranged for sequentially exciting one or more DL antenna ports through a sequential radiation of the incident electric field at a measurement period in one or more of aggressor carrier component arranged in at least one antenna port 210. The at least one signal injection module 204 arranged for scanning each DL transmission of each radiated antenna port of the one or more radiated antenna ports after each sequential radiation. Further, the at least one UL power measurement module 208 is arranged for measuring the uplink power for each DL transmission of each antenna port 210 after each scanning to identify a dominant DL antenna port, i.e., port 1 210-A, index for at least one radiated antenna port producing a maximum PIM excitation from the one or more radiated antenna ports.

[0067] Optionally, the at least one signal injection module 204 arranged for exciting the at least one DL dominant port, i.e., port 1 210-A, through the radiation of the incident electric field along with one or more other antenna ports, i.e., port 2 to port n, from a plurality of antenna ports 210 in the plurality of antenna ports 210. The one or more other antenna ports, i.e., port 2 to port n, are selected in a sequence for the excitation. The one or more other antenna ports, i.e., port 2 to port n, are excited based on an application of one or more relative phase shifts with respect to the at least one dominant port, i.e., port 1 210-A. Further, the at least one uplink power measurement module 208 is arranged for measuring, the uplink power value for each antenna port 210 during each relative phase shift from the one or more relative phase shifts. The at least one uplink power measurement module 208 is arranged for identifying at least one relative phase offset value from values of the one or more relative phase shifts that produces the maximum PIM excitation through the at least one other antenna port from the one or more other antenna ports, i.e., port 2 to port n, during the radiation. The maximum PIM excitation corresponds to the maximum power value of the at least one other antenna port.

[0068] Optionally, the relative phase offset is varied between 0 to 360 degrees.

[0069] Optionally, the at least one signal injection module 204 arranged for exciting at least one first dominant antenna port, i.e., port 1 210-A, along with the one or more other antenna ports, i.e., port 2 to port n, from the plurality of other antenna ports. The one or more other antenna ports are selected in a sequence. The one or more other antenna ports are excited based on an application of a relative phase shift value with respect to the at least one dominant antenna port, i.e., port 1 210-A, that maximizes the uplink PIM power for at least one other antenna port from the one or more other antenna ports, i.e., port 2 to port n. The one or more other antenna ports, i.e., port 2 to port n, are excited by varying a value of an amplitude of a scaling factor. Further, the at least one UL power measurement module 208 arranged for performing uplink power measurement for each other antenna port from the one or more other antenna ports, i.e., port 2 to port n, for each amplitude sea ling factor to identify a scaling factor that produces a maximum PIM excitation.

[0070] Optionally, the value of the amplitude in the amplitude scaling factor is varied in a range of 0 to 1.

[0071] Optionally, a total downlink power corresponding to a sum of downlink power of each antenna port for each value of the amplitude is held constantfordifferent values of amplitude scaling factors.

[0072] Optionally, the at least one control module 212 is arranged for reconstructing the at least one DL PIM steering vector from a plurality of DL PIM steering vectors for the at least one reflector 206 according to each of the value of the relative phase offset and the value of the amplitude scaling factors that maximize the PIM excitation for different DL antenna ports from the plurality of antenna ports 210. The at least one DL PIM steering vector is reconstructed accordingto the performance of the one or more steps of the radiation of the incident electric field on each antenna port 210 and measurement of the UL power value for each DL transmission.

[0073] Optionally, the at least one signal injection module 204 is arranged in one wireless transceiver 202 in a plurality of wireless transceivers and wherein the at least one uplink power measurement module 208 is arranged in other wireless transceiver in the plurality of wireless transceivers.

[0074] Optionally, the PIM source is located inside the wireless transceiver such as an inline PIM source 214. For example, the inline PIM source 214 may be a bad cable or bad connector. This is a PIM that is generated from one DL port.

[0075] In Fig. 3-A illustrates an example where port 1 which is also referred to as 210-A, is a dominant port generating maximum PIM excitation.

[0076] Fig. 3-B is a schematic block diagram illustrating an alternative embodiment where one or more DL aggressor carriers and / or one or more UL victim carriers are transmitted / received from one WT instance 202-A, and wherein one or more DL aggressor carriers and / or one or more UL victim carriers are transmitted / received from at least one other WT instance 202-B. Fig. 3-B shows that some of the proposed method modules such as the at least one control module 212, the at least one DL signal injection module 204 and the UL power measurement module 208 may be distributed and replicated in various subsystems in the wireless network lOOsuch as some Cloud Processing Unit, or some Digital Unit ,DU, or some Radio Unit, RU, or a combination thereof.

[0077] The foregoing description of the specific examples will so fully reveal the general nature of the examples herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific examples without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed examples. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the examples herein have been described in terms of preferred examples, those skilled in the art will recognize that the examples herein can be practiced with modification within the scope of the disclosure. Fig. 4 shows a flowchart illustrating steps for a computer implemented method 400 performed through the wireless system 200 for measuring DL PIM steering vectors for at least one WT 202 in the wireless network according to some embodiments.

[0078] At step 402, the method 400 comprises radiating, through at least one signal injection module 204, an incident electric field on each antenna port 210 from the plurality of antenna ports 210 to illuminate at least one PIM reflector 206 from a plurality of PIM reflectors 206 arranged in a surrounding environment of the plurality of antenna ports 210.

[0079] At step 404, the method 400 comprises performing, through at least one signal injection module 204, scanning of each radiated antenna port 210 from a plurality of radiated antenna ports 210 to measure an uplink, UL, power value for each DL transmissions from a plurality of DL transmissions, from one or more radiated antenna port 210 of the plurality of radiated antenna ports 210. The uplink power is generated due to the illumination of the at least one PIM reflector 206.

[0080] At step 406, the method 400 comprises computing, through at least one uplink power measurement module 208, an Uplink, UL, power value for each DL transmission from one or more radiated antenna port 210.

[0081] At step 408, the method 400 comprises reconstructing, through at least one control module 212 in communication with each of the at least one signal injection module 204 and at least one uplink power measurement module 208, at least one DL PIM steering vector for at least one antenna port from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission.

[0082] In an example, in PIM modelling, i.e., the PIM measurements, the detailed analysis and development of the proposed learning method 400 is presented. The PIM occur due to nonlinear reflectors 206 that are excited by two carrier components, where the intermodulation products lie in the UL frequency band. Consider, for the Wireless Transceiver, WT, 202 having the plurality of ports 210, i.e., alternatively referred to as an antenna array of N radiators, the electric-field incident on an external PIM source 206 corresponding to the frequency of a primary downlink aggressor, is denoted by:

[0083] While that of a secondary downlink aggressor, is denoted by: piM,DL2= 5PIM,DL2VDL2' (2)

[0084] Where the N x 1 vectors sPIM DLiand SPIM,DL2a rethe at least two PIM steering vectors, alternatively referred as DL PIM steering vectors, for the primary and secondary aggressor, respectively. While the N x 1 vectors vD |and vDLzare DL excitations applied to the plurality of ports 210 for the primary and secondary aggressors, respectively.

[0085] A phasor of the induced current in the PIM source due to the DL excitation, corresponding to an intermodulation product (IM3), which lies in the UL frequency band, due to the incident DL electric-fields corresponding to the primary and secondary aggressors can be expressed as:

[0086] Where cn nare coefficients that model the non-linear behaviour of the PIM source. This induced current in the external PIM source 206 radiates back to the wireless transceiver 202, i.e., for example a radio equipment, and the N x 1 vector of phasors measured at, at least one port from the plurality of ports 210, for example, an antenna port can be given as:

[0087] The norm of this vector can be treated as the UL PIM power and is expressed as:

[0088] It may be seen from equations (1) to (5) that the UL PIM power increases with increasing the correlation between the applied excitations and the at least one PIM steering vector from each polarizations of the primary aggressor. Similarly, by nullifying the electric-field due to the primary aggressor at the PIM source, the induced current in the external PIM source 206 due to the IM3 component may also be nullified. For another example, the proposed method 400 is configured to estimate the at least two PIM steering vectors, i.e., the DL PIM steering vector, of the primary aggressor to at least one inline PIM source 214. For the plurality of ports 210 with the pair of polarization, i.e., each port referring to a cross-polarized radiator, each polarization is treated separately in the proposed method 400 while providing PIM measurements.

[0089] In addition, the proposed method 400 is further explained using an implementation example as described below:

[0090] For example, the proposed method 400 involves controlling the DL excitations applied for the primary and secondary aggressors, vD |and vDLz, while monitoring the power, PUL, of the received UL vector, vUL. For each antenna polarization, the following four steps are being performed as given below:

[0091] For example, radiating an incident electric field on each antenna port 210 from the plurality of antenna ports 210 to illuminate at least one PIM reflector 206, as defined in step 402 of Fig.4 may comprise the following. First, a set of excitations is found, for the plurality of ports 210 at a frequency corresponding to the secondary aggressor to increase the illumination of the external PIM source 206. o The proposed method 400 aims to improve the quality, i.e., the PIM-to-Noise ratio, of the received UL PIM signal in the following steps. For example, for one of the pair of polarizations, {+45°, —45°}, the DL excitations for both the primary and secondary aggressors are given as Discrete Fourier Transform (DFT)-beams: o Where the excitations are maintained over a fixed period T and then changed to others by changing the index m. The UL PIM power is measured over each fixed period T. o The index m* that corresponds to the highest or maximum UL PIM power is maintained throughout the following steps, i.e., second step, third step and fourth step, for the DL excitations of the secondary aggressor, such that: For example, performing scanning of each radiated antenna port 210 from a plurality of radiated antenna ports 210 to measure an uplink, UL, power value for each DL transmissions from a plurality of DL transmissions as defined in step 404 of Fig. 4 may comprise the following. Second, the scanning is made to identify at least one dominant port 210-A from the plurality of ports 210 of the DL primary aggressor that has the most / maximum contribution to the UL PIM power. o The at least one DL signal injection module 204 is arranged to perform through the incident electric field, the second DL excitation of at least one dominant port 210-A from the plurality of ports 210 selected in a sequence. For instance, sequentially exciting only one port in the DL primary aggressor over the fixed period T, and then switching to another port. o Alternatively, in steps two to four of the proposed method 400, other ports, i.e., port 2 to port n, may be concurrently excited to help increase the total DL power. However, the other ports, i.e., port 2 to port n, would experience a power back-off with respect to the at least one dominant port 210-A under scanning. o The UL PIM power is measured over each period and the index of the plurality of ports 210 to identify the at least one dominant port 210-A with the highest or maximum UL PIM power and is recorded, n*. o The at least first port 210-A that corresponds to the highest / maximum UL PIM power is fixed with a unit excitation over the next scanning steps. o The importance of finding the dominant port, i.e., the at least one dominant port 210-A from the plurality of ports 210 having the maximum Uplink Passive Intermodulation, UL PIM, power is highlighted / explained in detail in the third and fourth steps of the proposed method 400.

[0092] For example, computing, an Uplink, UL, power value for each DL transmission from one or more radiated antenna port 210 as defined in step 406 of Fig. 4 may comprise the following. Third, computing is made to obtain at least one relative phase change after the second DL excitation from the one or more relative phase changes for each of the one or more antenna ports 210 with respect to the at least first port 210-A, i.e., the dominant port. o The at least first port 210-A is excited with a unit excitation and the one or more other ports, port 2 to port n, also referred as, one or more additional ports, is excited with a unit excitation by applying a relative phase change. o The relative phase change is maintained over a fixed duration T and varied to scan the plurality of ports 210 between 0° to 360° degrees range. o The UL PIM power is measured over each fixed period T. The phase change that corresponds to the highest / maximum UL PIM power is recorded to be used in the fourth step, < > . o The third step in the proposed method 400 -is repeated for the N — 1 ports in conjunction with the at least first port 210-A.

[0093] For example, computing, an Uplink, UL, power value for each DL transmission from one or more radiated antenna port 210 as defined in step 406 of Fig. 4 may comprise the following.! Fourth, computing is made to obtain at least one relative scaling factor for the one or more other ports, port 2 to port n, relative to the at least first port 210- A. The importance of finding the at least first port 210-A is that it limits the relative scaling factor to be between 0 and 1. o The total input power delivered to the plurality of ports 210, i.e., antenna array, is held constant throughout the DL excitations, i.e., the first DL excitation, the second DL excitation, the third DL excitation of the fourth step. o The at least first port 210-A is excited by:

[0094] Where tf is the dominant port index. o While the one or more other ports, port 2 to port n, i.e., the non-dominant ports are excited by using the previously recorded relative phase change and the appropriate relative scaling factor:

[0095] Where n is the port index. o The value of a is maintained over a period T and varied between 0 and 1. o The UL PIM power is measured over each period through the UL power measurement module 212 and the value of alpha that corresponds to the highest / maximum power is obtained and recorded, a„.

[0096] For example, reconstructing at least one DL PIM steering vector for at least one antenna port from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission as defined in step 408 of Fig. 4 may comprise the following. Reconstructing is made by combining the results from the previous steps of the radiating, corresponding steps of scanning, and computing UL power value, reconstructing the at least two PIM eigenvectors, i.e., the DL PIM steering vector for one polarization of the pair of polarizations is expressed as:

[0097] The first step, the second step, the third step and the fourth step of the proposed method 400 are then repeated for the other polarization of the pair of polarizations, where pol G {+45°, —45°}.

[0098] Finally, the null-steering is performed as follows:

[0099] Where IJNVis the Identity1matrix of size N corresponds to the far-field 1user traffic beam for polarization pol at the primary aggressor frequency DLi.

[0100] Fig. 5 illustrates an example-computing environment 500 implementing the wireless system 200 and the method 400 as shown in Fig. 3-A, Fig. 3-B, and Fig. 4 for measuring DL PIM steering vectors for at least one WT 202 deployed in the wireless network. As depicted in Fig. 5, the computing environment 500 comprises at least one data processing module 506 that is equipped with a control module 502 and an Arithmetic Logic Unit (ALU) 504, a plurality of networking devices 508 and a plurality Input output, I / O devices 510, a memory 512, a storage 514. The data processing module 506 may be responsible for implementing the platform and method described in Fig. 3-A, 3-B and Fig. 4 respectively. For example, the data processing module 506 in some embodiments be equivalent to the controlling circuitry of the platform described above in conjunction with Fig. 3-A, 3-B and Fig. 4. The data processing module 506 is capable of executing software instructions stored in memory 512. The data processing module 506 receives commands from the control module 502 in order to perform its processing. Further, any logical and arithmetic operations involved in the execution of the instructions are computed with the help of the ALU 504.

[0101] The computer program is loadable into the data processing module 506, which may, for example, be comprised in an electronic apparatus (such as the platform). When loaded into the data processing module 506, the computer program may be stored in the memory 512 associated with or comprised in the data processing module 506. According to some embodiments, the computer program may, when loaded into and run by the data processing module 506, cause execution of method steps according to, for example, any of the methods illustrated in Fig. 3-A, 3-B and Fig. 4, or otherwise described herein.

[0102] The overall computing environment 500 may be composed of multiple homogeneous and / or heterogeneous cores, multiple CPUs of different kinds, special media and other accelerators. Further, the plurality of data processing modules 506 may be located on a single chip or over multiple chips.

[0103] The algorithm comprising of instructions and codes required for the implementation are stored in either the memory 512 or the storage 514 or both. At the time of execution, the instructions may be fetched from the corresponding memory 512 and / or storage 514 and executed by the data processing module 506.

[0104] In case of any hardware implementations various networking devices 508 or external I / O devices 510 may be connected to the computing environment to support the implementation through the networking devices 508 and the I / O devices 510.

[0105] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in Fig. 5 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

Claims

CLAIMS1. A wireless system (200) arranged for measuring Downlink (DL) Passive Intermodulation, PIM, steering vectors, for at least one wireless transceiver (202) having a plurality of antenna ports (210), wherein the wireless system (200) comprising: at least one signal injection module (204) arranged for: radiating an incident electric field on each antenna port (210) from the plurality of antenna ports (210) to illuminate at least one PIM reflector (206) from a plurality of PIM reflectors (206) arranged in a surrounding environment of the plurality of antenna ports (210); performing scanning of each radiated antenna port (210) from a plurality of radiated antenna ports (210) to measure an uplink, UL, power value for each DL transmissions from a plurality of DL transmissions, from one or more radiated antenna port (210) of the plurality of radiated antenna ports (210), wherein the uplink power is generated due to the illumination of the at least one PIM reflector (206); at least one uplink power measurement module (208) arranged for: computing an Uplink, UL, power value for each DL transmission from one or more radiated antenna port (210); and at least one control module (212) in communication with each of: the at least one signal injection module (204) and at least one uplink power measurement module (208), wherein the at least one control module (212) is arranged for: reconstructing at least one DL PIM steering vector for at least one antenna port (210) from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission.

2. The wireless system (200) according to claim 1, wherein the radiation of the incident electric field on each antenna port (210) and the scanning of each DL transmission is performed in one or more steps from a plurality of steps for one or more antenna polarization.

3. The wireless system (200) according to claim 2, wherein the scanning is Passive Intermodulation, PIM scanning, performed after performance of each step of the one or more steps of radiation of the incident electric field on each antenna port (210).

4. The wireless system (200) according to any of the preceding claims, wherein the at least one control module (212) is arranged for: coordinating each step from the one or more steps of: performance of the radiation of the incident electric field on each antenna port (210) and measurement of the UL power value for each DL transmission.

5. The wireless system (200) according to any of the preceding claims, wherein the at least one uplink power measurement module (212) is arranged for: identifying a beam index for at least one beam from a plurality of beams for each DL transmission producing a maximum PIM excitation, wherein the maximum PIM excitation is identified according to measurement of a UL power value for each beam from the plurality of beams, wherein the at least one beam producing the maximum PIM excitation is having a maximum UL power value compared to UL power value of other beams from the plurality of beams, wherein the at least one beam producing the maximum PIM excitations lies in an aggressor carrier of the at least one antenna port (210) from the plurality of antenna ports (210).

6. The wireless system (200) according to any of the preceding claims, comprising the at least one signal injection module (204) arranged for: radiating in one of the aggressor carrier component in the at least one antenna port (210), the at least one beam from the plurality of beams producing the maximum PIM excitation through the incident electric field, wherein the at least one beam from the plurality of beams producing the maximum PIM excitation is radiated for measurement of the uplink power value according to the maximum PIM excitation, along with other DL transmissions from the plurality of antenna ports (210) in one or more other aggressor carrier component.

7. The wireless system (200) according to of any preceding claims, wherein the at least one signal injection module (204) arranged for:sequentially exciting one or more DL antenna ports through a sequential radiation of the incident electric field at a measurement period in one or more of aggressor carrier component arranged in at least one antenna port (210); scanning each DL transmission of each radiated antenna port (210) of the one or more radiated antenna ports (210) after each sequential radiation; and measuring the uplink power for each DL transmission of each antenna port (210) after each scanning to identify a dominant DL antenna port (210-A) index for at least one radiated antenna port (210) producing a maximum PIM excitation from the one or more radiated antenna ports (210).

8. The wireless system (200) of any of the preceding claims, comprising: the at least one signal injection module (204) arranged for: exciting the at least one DL dominant port (210-A) through the radiation of the incident electric field along with one or more other antenna ports from a plurality of antenna ports (210) in the plurality of antenna ports (210), wherein the one or more other antenna ports are selected in a sequence for the excitation, wherein the one or more other antenna ports are excited based on an application of one or more relative phase shifts with respect to the at least one dominant port (210-A) wherein the at least one uplink power measurement module (208) is arranged for: measuring, the uplink power value for each antenna port (210) during each relative phase shift from the one or more relative phase shifts; and identifying at least one relative phase offset value from values of the one or more relative phase shifts that produces the maximum PIM excitation through the at least one other antenna port from the one or more other antenna ports during the radiation, wherein the maximum PIM excitation corresponds to the maximum power value of the at least one other antenna port.

9. The wireless system (200) according to claim 8, wherein the relative phase offset is varied between 0 to 360 degrees.

10. The wireless system (200) according to any of the preceding claims, comprising: the at least one signal injection module (204) arranged for:exciting at least one first dominant antenna port (210-A) along with the one or more other antenna ports from the plurality of other antenna ports (210), wherein the one or more other antenna ports are selected in a sequence, wherein the one or more other antenna ports are excited based on an application of a relative phase shift value with respect to the at least one dominant antenna port (210-A) that maximizes the uplink PIM power for at least one other antenna port from the one or more other antenna ports (210), wherein the one or more other antenna ports (210) are excited by varying a value of an amplitude of a scaling factor; and performing uplink power measurement for each other antenna port from the one or more other antenna ports (210) for each amplitude scaling factor to identify a scaling factor that produces a maximum PIM excitation.

11. The wireless system (200) according to claim 10, wherein the value of the amplitude in the amplitude scaling factor is varied in a range of 0 to 1.

12. The wireless system (200) according to any of the claims 10 or 11, wherein a total downlink power corresponding to a sum of downlink power of each antenna port (210) for each value of the amplitude is held constant for different values of amplitude scaling factors.

13. The wireless system (200) of any preceding claims, wherein the at least one control module (212) is arranged for: reconstructing the at least one DL PIM steering vector from a plurality of DL PIM steering vectors for the at least one reflector (206) according to each of the value of the relative phase offset and the value of the amplitude scaling factors that maximize the PIM excitation for different DL antenna ports from the plurality of antenna ports, wherein the at least one DL PIM steering vector is reconstructed according to the performance of the one or more steps of the radiation of the incident electric field on each antenna port (210) and measurement of the UL power value for each DL transmission.

14. The wireless system (200) of any of the preceding claims, wherein the at least one signal injection module (204) is arranged in one wireless transceiver (202) in a plurality of wireless transceivers (202) and wherein the at least one uplink power measurementmodule (208) is arranged in other wireless transceiver in the plurality of wireless transceivers (202).

15. The wireless system (200) according to any of the preceding claims, wherein the PIM source is located inside the wireless transceiver (202) such as an inline PIM source (214).

16. A computer implemented method performed in a wireless system (200) arranged for measuring Downlink, DL, Passive Intermodulation, PIM, steering vectors, for at least one wireless transceiver (202) having a plurality of antenna ports (210), wherein the method comprising: radiating, through an at least one signal injection module (204), an incident electric field on each antenna port (210) from the plurality of antenna ports (210) to illuminate at least one PIM reflector (206) from a plurality of PIM reflectors (206) arranged in a surrounding environment of the plurality of antenna ports (210); performing, through the at least one signal injection module (204), scanning of each radiated antenna port (210) from a plurality of radiated antenna ports (210) to measure an uplink, UL, power value for each DL transmissions from one or more radiated antenna port (210) of the plurality of radiated antenna ports (210), wherein the uplink power is generated due to the illumination of the at least one PIM reflector (206); computing, through at least one uplink power measurement module (208) an Uplink, UL, power value for each DL transmission from one or more radiated antenna port (210); and reconstructing, through at least one control module (212) in communication with each of: the at least one signal injection module (204) and at least one uplink power measurement module (208), at least one DL PIM steering vector for at least one antenna port (210) from one or more DL PIM steering vectors obtained from each UL power value computed for each DL transmission.

17. The method according to claim 16, wherein the radiation of the incident electric field on each antenna port (210) and the scanning of each DL transmission is performed in one or more steps from a plurality of steps for one or more antenna polarization.

18. The method according to claim 17, wherein the scanning is Passive Intermodulation, PIM scanning, performed after performance of each step of the one or more steps of radiation of the incident electric field on each antenna port (210).

19. The method according to claims 16-18, comprising: coordinating each step from the one or more steps of: performance of the radiation of the incident electric field on each antenna port (210) and measurement of the UL power value for each DL transmission.

20. The method according to claims 16-19, comprising: identifying a beam index for at least one beam from a plurality of beams for each DL transmission producing a maximum PIM excitation, wherein the maximum PIM excitation is identified according to measurement of a UL power value for each beam from the plurality of beams, wherein the at least one beam producing the maximum PIM excitation is having a maximum UL power value compared to UL power value of other beams from the plurality of beams, wherein the at least one beam producing the maximum PIM excitations lies in an aggressor carrier of the at least one antenna port (210) from the plurality of antenna ports (210).

21. The method according to claims 16-20, comprising:Radiating in one of the aggressorcarriercomponent in the at least one antenna port (210), the at least one beam from the plurality of beams producing the maximum PIM excitation through the incident electric field, wherein the at least one beam from the plurality of beams producing the maximum PIM excitation is radiated for measurement of the uplink power value according to the maximum PIM excitation, along with other DL transmissions from the plurality of antenna ports (210) in one or more other aggressor carrier component.

22. The method according to claims 16-21, comprising: sequentially exciting one or more DL antenna ports through a sequential radiation of the incident electric field at the measurement period in one or more of the aggressor carrier component, scanning each DL transmission of each radiated antenna port of the one or more radiated antenna ports (210) after each sequential radiation; and measuring the uplink power for each DL transmission of each antenna port (210) after each scanning to identify a dominant DL antenna port (210-A) index for atleast one radiated antenna port (210) producing a maximum PIM excitation from the one or more radiated antenna ports (210).

23. The method according to claims 16-22, comprising: exciting, through the at least one signal injection module (204), the at least one DL dominant port (210-A) through the radiation of the incident electric field along with one or more other antenna ports from a plurality of antenna ports (210) in the plurality of antenna ports (210), wherein the one or more other antenna ports are selected in a sequence for the excitation, wherein the one or more other antenna ports are excited based on an application of one or more relative phase shifts with respect to the at least one dominant port (210-A) measuring, through the at least one control module (212) the uplink power value for each antenna port during each relative phase shift from the one or more relative phase shifts; and identifying, through the at least one control module (212) at least one relative phase offset value from values of the one or more relative phase shifts that produces the maximum PIM excitation through the at least one other antenna port from the one or more other antenna ports during the radiation, wherein the maximum PIM excitation corresponds to the maximum power value of the at least one other antenna port.

24. The method according to claim 23, wherein the relative phase offset is varied between 0 to 360 degrees.

25. The method according to claims 16-24, comprising: exciting, through the at least one signal injection module (204), at least one first dominant antenna port (210-A) along with the one or more other antenna ports from the plurality of other antenna ports (210), wherein the one or more other antenna ports are selected in a sequence, wherein the one or more other antenna ports are excited based on an application of a relative phase shift value with respect to the at least one dominant antenna port (210-A) that maximizes the uplink PIM power for at least one other antenna port from the one or more other antenna ports, wherein the one or more other antenna ports are excited by varying a value of an amplitude of a scaling factor; andperforming uplink power measurement for each other antenna port from the one or more other antenna ports for each amplitude scaling factor to identify a scaling factor that produces a maximum PIM excitation.

26. The method according to claim 25, wherein the value of the amplitude in the amplitude scaling factor is varied in a range of 0 to 1.

27. The method according to any of the claims 25 or 26, wherein a total downlink power corresponding to a sum of downlink power of each antenna port for each value of the amplitude is held constant for different values of amplitude scaling factors.

28. The method according to claims 16-27, comprising: reconstructing, through the at least one control module (212), the at least one DL PIM steering vector from a plurality of DL PIM steering vectors for the at least one reflector (206) according to each of the value of the relative phase offset and the value of the amplitude scaling factors that maximize the PIM excitation for different DL antenna ports from the plurality of antenna ports (210), wherein the at least one DL PIM steering vector is reconstructed according to the performance of the one or more steps of the radiation of the incident electric field on each antenna port (210) and measurement of the UL power value for each DL transmission.

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