WO2021209792A1

WO2021209792A1 - Method and system for configurable interference mitigation

Info

Publication number: WO2021209792A1
Application number: PCT/IB2020/053614
Authority: WO
Inventors: Majid Bavand; Israfil Bahceci; Bhushan BILLADE; Svante Bergman
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2020-04-16
Filing date: 2020-04-16
Publication date: 2021-10-21

Abstract

Methods and apparatuses are provided for a network node to reduce interference toward target areas. The network node is configured to receive an approximate position or direction of a target and determine beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is 5 created in a radiation pattern of the array of antennas in the approximate direction of the target. The null may be created using a zero forcing function to calculate a null steering vector for the array of antennas. The network node may set a width of the null or use a carrier frequency to configure the null. The network node may also map the null to a corresponding vertical tilt and/or a horizontal swivel value that vertically 10 tilts and horizontal swivels the radiation pattern of the array of antennas. A precoder may enforce the null.

Description

METHOD AND SYSTEM FOR CONFIGURABLE INTERFERENCE

MITIGATION

TECHNICAL FIELD

The present disclosure relates wireless communications and, in particular, to a network node reducing interference toward target areas.

BACKGROUND

Active antenna system (AAS) is one of the technologies adopted by the 3^rd Generation Partnership Project (3GPP) for fourth generation (4G) Long-term Evolution (LTE) and fifth generation (5G) (also known as New Radio (NR)) systems to enhance the wireless networks performance, capacity and coverage by using multi antenna approaches such as diversity, spatial multiplexing and beamforming. A typical AAS system may include a two-dimensional antenna array with M rows, N columns and K polarizations (K=2 in case of cross -polarization) as shown in FIG 1.

Down link (DL) transmission can be categorized as feedback-based transmission and non-feedback-based transmissions. Non-feedback-based transmissions can include broadcast signals or wireless device (WD) specific signals. For example in NR, the Physical Broadcast Channel (PBCH), Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and their associated Demodulation Reference Signals (DMRSs) are non-feedback based channels/signals that are broadcasted to all WDs in the cell while in codebook based transmissions Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), and their associated DMRSs before Channel State Information (CSI) feedback (Precoding Matrix Indicators (PMI)/Channel Quality Information (CQI)/Rank Indicator (RI)/ CSI-RS Resource Indicator (CRI)) are considered non-feedback-based channels/signals that are transmitted to a specific WD. Beamforming techniques used in non-feedback-based transmissions may be called common channel beamforming since they do not employ WD specific information. When PMI feedback is available or reciprocity-assisted transmissions (RAT) are employed, PDSCH/PDCCH can be beamformed towards the specific WD to increase throughput and quality of service. For all these transmission modes in AAS systems, an operator may want to reduce interference towards a certain strategic location. For example, in Japan, the 5G NR frequency band coexists with the fixed satellite downlink frequency band. FIG. 2 illustrates such a situation using an earth station 4, WDs 6a and 6b, network nodes 8a and 8b, and a satellite 10. As shown, network nodes 8a and 8b and WDs 6a and 6b create interference with transmissions between satellite 10 and earth station 4. In these situations, operators may be required to minimize the network nodes 8a and 8b interference towards the satellite earth station 4. Since satellite systems are communications systems, an earth station 4 may not be able to accept interference for even a short period of time. Another example is the border areas in European countries, wherein on one side of the border one operator may use/own/control the wireless communication spectrum and on the other side of the border another operator may use/own/control the wireless communication spectrum. In such situations, operators may be required to reduce interference towards each other’s coverage area. Another use case is public health. Some European countries want to minimize propagation towards child-care centers, preschools and other centers where children may be concentrated.

Existing strategies for interference mitigation may utilize cell power reduction and network node deployment to reduce interference towards target areas. Cell power reduction may negatively impact cell coverage and throughput. Network node deployment limits the possible placement of the network nodes by reducing the available network node positions near the location of satellite earth stations thereby reducing the interference produced towards the satellite earth stations. An electromagnetic field (EMF) power lock feature may also be used to reduce cell- wise radiation power. However, such a feature reduces the average time of the radiated power from a network node instead of controlling instantaneous transmit power towards a certain direction.

SUMMARY

Some embodiments of the present disclosure advantageously provide methods, apparatuses and systems related to reducing the interference towards one or more directions. An operator may determine the relative direction of the target areas with respect to a network node. The network node then uses this input to limit production of interference towards the determined directions. By producing a null or extensive attenuation area in the radiation pattern of the network node antenna array, interference towards the given target areas is reduced. Moreover, it is possible to control the characteristics, such as width, of the generated null or extensive attenuation area via the AAS configuration. Embodiments may utilize both vertical and horizontal null steering approaches for a two dimensional (2D) antenna array. Embodiments are applicable to one-dimensional antenna arrays as well.

According to one aspect of the present disclosure, a network node configured to communicate with at least one wireless device (WD) using an array of antennas is provided. The network node is configured to receive an approximate position or direction of at least one target and determine beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

In some embodiments of this aspect, the beam forming parameters are at least one of weights and digital or analog beam forming excitations. In some embodiments of this aspect, determining the beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises using a zero forcing function to calculate a null steering vector for the array of antennas that results in the at least one null or extensively attenuated area in the approximate direction of the at least one target. In some embodiments of this aspect, the network node comprises a precoder configured to enforce the at least one null or extensively attenuated area in the at least one targets approximate direction.

In some embodiments of this aspect, the network node is further configured to receive approximate positions or directions of a plurality of targets and determine the beam forming weights for the array of antennas such that a null or extensively attenuated area is created in the approximate direction of each of the plurality of targets. In some embodiments of this aspect, the network node is further configured to set a width of the null or extensively attenuated area. In some embodiments of this aspect, the network node is further configured to use a carrier frequency to configure the at least one null or extensively attenuated area. In some embodiments of this aspect, the network node is further configured to map the at least one null or extensively attenuated area to at least one of a corresponding vertical tilt and a horizontal swivel value. In some embodiments of this aspect, determining the beam forming weights for the array of antennas such that the null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises at least one of vertically tilting and horizontally swiveling the radiation pattern of the array of antennas.

In some embodiments of this aspect, the network node is further configured to receive feedback from the at least one target and adjust the beamforming parameters based at least upon the feedback. In some embodiments of this aspect, the network node is further configured to at least one of receive and determine a channel estimation of the at least one target area and adjust the beamforming parameters based at least upon the channel estimation.

According to another aspect of the present disclosure, a method for a network node to communicate with at least one wireless device (WD) using an array of antennas is provided. The method comprises receiving an approximate position or direction of at least one target and determining beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

In some embodiments of this aspect, the beam forming parameters are at least one of weights and digital or analog beam forming excitations. In some embodiments of this aspect, determining the beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises using a zero forcing function to calculate a null steering vector for the array of antennas that results in the at least one null or extensively attenuated area in the approximate direction of the at least one target. In some embodiments of this aspect, the method comprises using a precoder to enforce the at least one null or extensively attenuated area in the at least one targets approximate direction. In some embodiments of this aspect, the method further comprises receiving approximate positions or directions of a plurality of targets and determining the beam forming weights for the array of antennas such that a null or extensively attenuated area is created in the approximate direction of each of the plurality of targets. In some embodiments of this aspect, the method further comprises setting a width of the null or extensively attenuated area.

In some embodiments of this aspect, the method further comprises mapping the at least one null or extensively attenuated area to at least one of a corresponding vertical tilt and a horizontal swivel value. In some embodiments of this aspect, the method further comprises using a carrier frequency to configure the at least one null or extensively attenuated area. In some embodiments of this aspect, determining the beam forming weights for the array of antennas such that the null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises at least one of vertically tilting and horizontally swiveling the radiation pattern of the array of antennas.

In some embodiments of this aspect, the method further comprises receiving feedback from the at least one target and adjusting the beamforming parameters based at least upon the feedback. In some embodiments of this aspect, the method further comprises at least one of receiving and determining a channel estimation of the at least one target area and adjusting the beamforming parameters based at least upon the channel estimation.

Various embodiments described herein give an operator the opportunity to reduce interference towards certain horizontal or vertical directions with minimal impact on cell and WD throughput. This interference reduction approach may be used to improve other communication systems deployed in the same band, for example fixed satellite downlink in the same band as 5G NR, to benefit public health such as by reducing radiation towards schools, and/or to improve possible network node placement. Embodiments may also introduce additional tapering to port to antenna (P2A) mapping which can be considered as an indirect energy improvement and/or green communication strategy. BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a block diagram of a two-dimensional antenna element array;

FIG. 2 is an example scenario where a network node needs to reduce interference towards satellite earth stations;

FIG. 3 is a schematic diagram of an example network architecture illustrating a communication system according to the principles in the present disclosure;

FIG. 4 is a block diagram of a network node in communication with a wireless device over an at least partially wireless connection according to some embodiments of the present disclosure;

FIG. 5 is a flowchart of an example method for a network node for reducing interference in the direction of a target area according to some embodiments of the present disclosure;

FIG. 6 is an illustration of an example spherical coordinate system;

FIG. 7 is an illustration of an example two-dimensional antenna array located on the x-z plane of the spherical coordinate system;

FIG. 8 is an illustration of a radiation pattern with a narrow null at 0° according to some embodiments of the present disclosure;

FIG. 9 is an illustration of a radiation pattern with a wide null at 0° according to some embodiments of the present disclosure;

FIG. 10 is an illustration of a radiation pattern generated with 7 nulls with only 8 antenna ports according to some embodiments of the present disclosure; and

FIG. 11 is a graphical illustration of the dependency of a null to both horizontal and vertical angles according to some embodiments of the present disclosure.

DETAIFED DESCRIPTION

As discussed above, there is a general problem of network nodes creating interference towards one or more target areas. In accordance with embodiments described herein, operators may determine the relative direction of the target area with respect to the network nodes. The networks nodes may then use this input to reduce any interference produced towards the given directions by producing nulls in the radiation patterns of the network node antenna arrays. Moreover, it is possible to control the characteristics such as width of the generated null via the antenna array configuration. Some embodiments may utilize both vertical and horizontal null steering approaches for a 2D antenna array while other embodiments are applicable to one-dimensional arrays. Such embodiments give an operator the opportunity to reduce interference towards certain horizontal or vertical directions with minimal impact on cell and WD throughput. Embodiments may also utilize interference reduction approaches as described herein to improve other communication systems deployed in the same band, for example, fixed satellite downlinks provided in the same band as 5G NR. Embodiments may also benefit public health such as by reducing radiation directed towards schools and improve network node placement. Embodiments may further introduce additional tapering to port to antenna (P2A) mapping which can be considered as an indirect energy improvement and/or green communication strategy.

Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to dynamic machine learning decision threshold for resource allocation. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. 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. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi- standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU), Remote Radio Head (RRH), baseband unit (BBU), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node. In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device, etc.

Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell/multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

In some embodiments, the term “allocation” may be considered to refer to a WD being allocated one or more resources for a transmission, such as, for example, allocating a radio resource on a channel for a signal to be transmitted to or from the WD (e.g., time-frequency resource for SRS on a physical uplink channel). In some embodiments, a network node may allocate resources by scheduling a WD and, for example, configuring the WD with the allocated resources via e.g., radio resource control (RRC) signaling in a higher layer and/or by signaling an indication of the allocated resources in a physical layer via e.g., a grant in downlink control information (DCI).

In some embodiments, the term “radio resource” is intended to indicate a frequency resource and/or a time resource. The time resource may correspond to any type of physical resource or radio resource expressed in terms of length of time. Examples of time resources are: symbol, time slot, subframe, radio frame, transmission time interval (TTI), interleaving time, etc. The frequency resource may correspond to one or more resource elements, subcarriers, resource blocks, bandwidth part and/or any other resources in the frequency domain. The radio resource may also indicate a combination of subcarriers, time slots, codes and/or spatial dimensions.

Even though the descriptions herein may be explained in the context of one of a Downlink (DL) and an Uplink (UL) communication, it should be understood that the basic principles disclosed may also be applicable to the other of the one of the DL and the UL communication. Lor DL communication, the network node is the transmitter and the receiver is the WD. Lor the UL communication, the transmitter is the WD and the receiver is the network node.

Although some the examples herein may be explained in the context of a WD being allocated radio resources on a physical channel for a periodic reference signal (e.g., SRS), it should be understood that the principles may also be applicable to other signals and other types of resources or other channels.

In some embodiments, the allocated radio resource may be allocated for a particular signal and on a particular channel. Signaling may generally comprise one or more symbols and/or signals and/or messages. A signal may comprise or represent one or more bits. An indication may represent signaling, and/or be implemented as a signal, or as a plurality of signals. One or more signals may be included in and/or represented by a message. Signaling, in particular control signaling, may comprise a plurality of signals and/or messages, which may be transmitted on different carriers and/or be associated to different signaling processes, e.g. representing and/or pertaining to one or more such processes and/or corresponding information. An indication may comprise signaling, and/or a plurality of signals and/or messages and/or may be comprised therein, which may be transmitted on different carriers and/or be associated to different acknowledgement signaling processes, e.g. representing and/or pertaining to one or more such processes. Signaling associated to a channel may be transmitted such that represents signaling and/or information for that channel, and/or that the signaling is interpreted by the transmitter and/or receiver to belong to that channel. Such signaling may generally comply with transmission parameters and/or format/s for the channel.

A channel may generally be a logical, transport or physical channel. A channel may comprise and/or be arranged on one or more carriers, in particular a plurality of subcarriers. A channel carrying and/or for carrying control signaling/control information may be considered a control channel, in particular if it is a physical layer channel and/or if it carries control plane information. Analogously, a channel carrying and/or for carrying data signaling/user information may be considered a data channel, in particular if it is a physical layer channel and/or if it carries user plane information. A channel may be defined for a specific communication direction, or for two complementary communication directions (e.g., UL and DL, or sidelink in two directions), in which case it may be considered to have at least two component channels, one for each direction. Examples of channels comprise a channel for low latency and/or high reliability transmission, in particular a channel for Ultra-Reliable Low Latency Communication (URLLC), which may be for control and/or data. In some embodiments, the channel described herein may be an uplink channel and in further embodiments may be a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH). In some embodiments, the channel may be a downlink channel, such as, a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH).

Transmitting in downlink may pertain to transmission from the network or network node to the terminal. The terminal may be considered the WD or UE. Transmitting in uplink may pertain to transmission from the terminal to the network or network node. Transmitting in sidelink may pertain to (direct) transmission from one terminal to another. Uplink, downlink and sidelink (e.g., sidelink transmission and reception) may be considered communication directions. In some variants, uplink and downlink may also be used to described wireless communication between network nodes, e.g. for wireless backhaul and/or relay communication and/or (wireless) network communication for example between base stations or similar network nodes, in particular communication terminating at such. It may be considered that backhaul and/or relay communication and/or network communication is implemented as a form of sidelink or uplink communication or similar thereto.

Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Some embodiments provide for reducing interference toward a target area by receiving an approximate position or direction of at least one target and determining beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 3 a schematic diagram of a communication system 16, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and/or NR (5G), which comprises an access network 18, such as a radio access network, and a core network 20. The access network 18 comprises a plurality of network nodes 21a, 21b, 21c (referred to collectively as network nodes 21), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 22a, 22b, 22c (referred to collectively as coverage areas 22). Each network node 21a, 21b, 21c is connectable to the core network 20 over a wired or wireless connection 24. A first wireless device (WD) 6a located in coverage area 22a is configured to wirelessly connect to, or be paged by, the corresponding network node 21a. A second WD 6b in coverage area 22b is wirelessly connectable to the corresponding network node 21b. While a plurality of WDs 6a, 6b (collectively referred to as wireless devices 6) 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 21. Note that although only two WDs 6 and three network nodes 21 are shown for convenience, the communication system may include many more WDs 6 and network nodes 21.

Also, it is contemplated that a WD 6 can be in simultaneous communication and/or configured to separately communicate with more than one network node 21 and more than one type of network node 21. For example, a WD 6 can have dual connectivity with a network node 21 that supports LTE and the same or a different network node 21 that supports NR. As an example, WD 6 can be in communication with an eNB for LTE/E-UTRAN and a gNB for NR/NG-RAN.

A network node 21 is configured to include an interference unit 26 which is configured to receive an approximate position or direction of at least one target and determine beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

Example implementations, in accordance with an embodiment, of the WD 6 and network node 21 discussed in the preceding paragraphs will now be described with reference to FIG. 4.

The communication system 16 further includes a network node 21 provided in a communication system 16 and including hardware 36 enabling it to communicate with the WD 6. The hardware 36 may include a communication interface 52 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 16, as well as a radio interface 54 for setting up and maintaining at least a wireless connection 56 with a WD 6 located in a coverage area 22 served by the network node 21. The radio interface 54 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

In the embodiment shown, the hardware 36 of the network node 21 further includes processing circuitry 28. The processing circuitry 28 may include a processor 30 and a memory 32. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 28 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 30 may be configured to access (e.g., write to and/or read from) the memory 32, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the network node 21 further has software 34 stored internally in, for example, memory 32, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 21 via an external connection. The software 34 may be executable by the processing circuitry 28. The processing circuitry 28 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node 21. Processor 30 corresponds to one or more processors 30 for performing network node 21 functions described herein. The memory 32 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 34 may include instructions that, when executed by the processor 30 and/or processing circuitry 28, causes the processor 30 and/or processing circuitry 28 to perform the processes described herein with respect to network node 21. For example, processing circuitry 28 of the network node 21 may include interference unit 26 configured to perform network node methods discussed herein, such as the methods discussed with reference to FIG. 5 as well as other figures. Processing circuitry 28 may also include and/or implement a precoder 25 that is used to enforce the nulls or extensively attenuated areas in the at least one targets approximate direction. In some embodiments precoder 25 may be a part of interference unit 26.

The communication system 16 further includes the WD 6 already referred to. The WD 6 may have hardware 48 that may include a radio interface 38 configured to set up and maintain a wireless connection 56 with a network node 21 serving a coverage area 22 in which the WD 6 is currently located. The radio interface 38 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

The hardware 48 of the WD 6 further includes processing circuitry 44. The processing circuitry 44 may include a processor 40 and memory 42. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 44 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 40 may be configured to access (e.g., write to and/or read from) memory 42, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the WD 6 may further comprise software 50, which is stored in, for example, memory 42 at the WD 6, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 6. The software 50 may be executable by the processing circuitry 44. The software 50 may include a client application 46. The client application 46 may be operable to provide a service to a human or non-human user via the WD 6. The client application 46 may interact with the user to generate the user data that it provides.

The processing circuitry 44 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD 6. The processor 40 corresponds to one or more processors 40 for performing WD 6 functions described herein. The WD 6 includes memory 42 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 50 and/or the client application 46 may include instructions that, when executed by the processor 40 and/or processing circuitry 44, causes the processor 40 and/or processing circuitry 44 to perform the processes described herein with respect to WD 6. For example, the processing circuitry 44 of the wireless device 6 may be configured to use resources and/or receive and/or transmit on radio resources (e.g., physical layer resources, such as, physical downlink control channel, physical downlink shared channel, physical uplink control channel and/or physical uplink shared channel, etc.) that are allocated to the WD 6 using one or more of the techniques disclosed herein.

In some embodiments, the inner workings of the network node 21 and WD 6, may be as shown in FIG. 4 and independently, the surrounding network topology may be that of FIG. 3.

Although FIGS. 3 and 4 show various “units” such as interference unit 26 as being within a processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 5 is a flowchart of an example method for a network node for reducing interference in the direction of a target area according to some embodiments of the present disclosure. One or more Blocks and/or functions and/or methods performed by the network node 21 may be performed by one or more elements of network node 21 such as by interference unit 26 in processing circuitry 28, processor 30, communication interface 52, radio interface 54, etc. according to the example method. The example method includes receiving (Block S58), such as by interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, an approximate position or direction of at least one target. The method includes determining (Block S60), such as by interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

In some embodiments, the beam forming parameters are at least one of weights and digital or analog beam forming excitations. In some embodiments, determining, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, the beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises using a zero forcing function to calculate a null steering vector for the array of antennas that results in the at least one null or extensively attenuated area in the approximate direction of the at least one target. In some embodiments, the method comprises using, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, a precoder 25 to enforce the at least one null or extensively attenuated area in the at least one targets approximate direction.

In some embodiments, the method further comprises receiving, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, approximate positions or directions of a plurality of targets and determining the beam forming weights for the array of antennas such that a null or extensively attenuated area is created in the approximate direction of each of the plurality of targets. In some embodiments, the method further comprises setting, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, a width of the null or extensively attenuated area.

In some embodiments, the method further comprises mapping, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, the at least one null or extensively attenuated area to at least one of a corresponding vertical tilt and a horizontal swivel value. In some embodiments, the method further comprises using, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, a carrier frequency to configure the at least one null or extensively attenuated area.

In some embodiments, determining the beam forming weights for the array of antennas such that the null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target further comprises at least one of vertically tilting and horizontally swiveling, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, the radiation pattern of the array of antennas.

In some embodiments, the method further comprises receiving, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, feedback from the at least one target and adjusting the beamforming parameters based at least upon the feedback In some embodiments, the method further comprises at least one of receiving and determining, such as via interference unit 26, processing circuitry 28, processor 30, communication interface 52 and/or radio interface 54, a channel estimation of the at least one target area and adjusting the beamforming parameters based at least upon the channel estimation.

Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for reducing interference, which may be implemented by the network node 21 and/or wireless device 6.

Some embodiments provide one or more techniques for both vertical and horizontal null steering and their configuration management. The position and/or direction of the targets may be given as an input to the network node 21. Network node 21 may, internally or externally, establish interference management techniques to reduce or cancel interference towards the target areas. One or multiple target areas can be given as input. Interference mitigation may also be done on one or all physical channels. In some embodiments, no feedback from the target area is required. However, embodiments may be extended to include feedback from target areas to better reduce interference. Further, embodiments may take into account the impact of multipath on the received power on target area or consider line of sight (LOS) propagation. Embodiments considering multipath effects may use feedback from the target area or channel estimation in the target area.

One embodiment for interference cancellation is directed toward horizontal nulling. However, embodiments may implement vertical nulling as well. Zero forcing (ZF) approaches can be employed to null-steer towards multiple directions. For beam/radiation pattern generation, a spherical coordinate system 62 as shown in FIG. 6 may be assumed.

It may also be assumed that a 2D array 64 as shown in FIG. 7 is located on the x-z plane, i.e., the broadside of the array is in the y direction.

For horizontal nulling, steering vector can be presented as:

\V_Q, ... ,

, where K is the number of nulls, ZF is the solution for finding w in the following system of linear equations:

V.w = 0

Which can be obtained as w^opt = (7 — V⁺V)u , where u is an Nxl vector of free parameters.

This means that more degrees of freedom are available to further optimize the beam by making the BFW to be as close as possible to the original beamforming weight or P2A mapping w₀. Therefore, the problem can be formulated as: min ||w — w₀||² subject to Vw = 0

The solution to this problem results in: w^o _P ^t _{= (/} _ v^H(VV^{H 1}V)w₀

For vertical null steering, the same solution is applicable except for the steering vector which is given by v =

in our assumed coordinate system.

Some embodiments may use a ZF approach to generate an antenna radiation pattern with multiple nulls. This capability helps not only to generate several narrow nulls but also to generate one, or more than one, wide null in the antenna radiation pattern. By placing two nulls very close to each other, embodiments may create a wider null and, therefore, reduce interference produced towards a larger area. Creation of wider nulls can also be used to compensate for error in mechanical vertical tilt or horizontal swivel error when installing a network node 21, or mechanical error caused by movement of an antenna array due to a disturbance such as wind. The distance between two nulls may be a configurable parameter used to control the width of the null. In the discussion below, this nonnegative parameter is named “nullWidthTuner”. While the below algorithm is directed toward generating two nulls, it can be generalized to include three or more nulls as needed to generate a composite null of the desired width.

If nullWidthTuner > 0 Each azimuthNull may be mapped to two null angles as: phiNulll = azimuthNull - nullWidthTuner /2 phiNull2 =azimuthNull + nullWidthTuner /2 elseif nullWidthTuner == 0 phiNull = azimuthNull; end

FIGS. 8 and 9 are graphical illustrations 66 and 68, respectively, of radiation patterns generated by embodiments to respectively have a narrow and a wide null at the middle of the coverage area using a ZF method as described herein. FIG. 10 is a graphical illustration 70 of a radiation pattern generated by an embodiment that generates multiple nulls when enough degrees of freedom are available. In FIGS.8- 10, trace 72 indicates the radiation patterns for a single element, trace 74 indicates the radiation pattern at a + 45 degree polarization, trace 76 indicates the radiation pattern at a -45 degree polarization, trace 78 indicates the radiation pattern for the total array and trace 80 indicates the radiation pattern without the creation of a null. As can be seen in horizontal nulling, the null position is not only dependent on the horizontal angle f but also to the vertical angle Q. FIG. 11 is a graphical illustration 82 of the dependency of a null to both horizontal and vertical angles. In such an embodiment, for generating a null in azimuth, both Q and f are taken as inputs for determining the direction of the null. However, for generating a null in elevation, only the angle Q may be required.

Embodiments described herein may utilize reciprocity assisted transmission (RAT) for interference cancellation. In such embodiments, a RAT precoder may consider generating a null in a desired direction or target area. The original minimum mean square error (MMSE) optimization problems or any other solution format for RAT, for example a regularized zero forcing solution, may be updated to include a constraint for enforcing a zero in the direction of target area. This may be accomplished by positioning a virtual WD 6 in the direction of target area and employing multiple-user (MU) multiple input multiple output (MIMO) instead of single-user (SU)-MIMO. In some embodiments, the virtual WD 6 channel may be basically utilized as the null steering vector. Other embodiments may utilize uniform weights for interference cancellation. In some such embodiments, vertical nulling implementation may be most suitable when the original beam weights are uniform or nearly uniform, i.e. when w₀ = [1] This may happen when the number of antenna ports is small, for example, when only

5 two ports are available. Embodiments rotate the coverage shape by vertical tilting or horizontal swiveling, but negate the beamforming weight (BFW) value of every other antenna element after the tilt/swivel. For horizontal nulling we have:

original BFW, and

10 index c is the column number of antenna element. In this formula, a positive f value is counter-clockwise rotation when looking to the front of antenna panel and a negative value is a clockwise rotation; and positive Q values are downward rotation and negative Q values are upward rotation in the vertical domain.

And for vertical nulling we have:

the original BFW, and index r is the row number of antenna element. Positive Q values are downward rotation in vertical domain.

Another embodiment for interference cancellation is described below. Instead

20 of taking the null location as an input, it is possible to provide a table to map a vertical tilt value or horizontal swivel value to its corresponding null. An example is given in the table below: elevationNull Corresponding Tilt (peak deviation from horizon)

25 15 1 4

-10 2.2

-5 5.9

0 9.7

5 13.5

30 In some embodiments described herein, an antenna array pattern will be configured by setting a number of nulls, the position of the nulls and the width of each null. There are a number of possible configuration approaches for taking the target area location and null characteristics as an input.

Some embodiments manage configuration by supporting multiple nulls in elevation and azimuth while elevation and azimuth nulls are completely independent; for each null, the width can be configured as set forth below. The parameter names used in the below examples are arbitrary and only used to illustrate the null configuration management concepts of the discussed embodiments. Any parameter names can be used.

• elevationNull[] o nullAngle o nullWidthTuner

• azimuthNull[] o horizontalAngle o verticalAngle o nullWidthTuner

Other embodiments manage configuration by supporting multiple nulls in elevation and azimuth while the theta angle for azimuth nulling is always set at 0°, both verticalNullWidthTuner and horizontalNullWidthTuner may be set to a default value as set forth below: elevationNull[] default = nil range: -90 : 0.1 : 90° azimuthNull[] default = nil range: -90 : 0.1 : 90°

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

What is claimed is:

1. A network node (21) configured to communicate with at least one wireless device (WD) (6) using an array of antennas, the network node (21) configured to: receive an approximate position or direction of at least one target; and determine beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

2. The network node (21) of Claim 1, wherein the beam forming parameters are at least one of weights and digital or analog beam forming excitations.

3. The network node (21) of Claims 1 or 2 wherein determining the beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises using a zero forcing function to calculate a null steering vector for the array of antennas that results in the at least one null or extensively attenuated area in the approximate direction of the at least one target.

4. The network node (21) of any one of Claims 1-3, comprising a precoder (25) configured to enforce the at least one null or extensively attenuated area in the at least one targets approximate direction.

5. The network node (21) of any one of Claims 1-4, further configured to receive approximate positions or directions of a plurality of targets and determine the beam forming weights for the array of antennas such that a null or extensively attenuated area is created in the approximate direction of each of the plurality of targets.

6. The network node (21) of any one of Claims 1-5, further configured to set a width of the null or extensively attenuated area.

7. The network node (21) of any one of Claims 1-6, further configured to use a carrier frequency to configure the at least one null or extensively attenuated area.

8. The network node (21) of any one of Claims 1-7, further configured to map the at least one null or extensively attenuated area to at least one of a corresponding vertical tilt and a horizontal swivel value.

9. The network node (21) of any one of Claims 1-8, wherein determining the beam forming weights for the array of antennas such that the null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises at least one of vertically tilting and horizontally swiveling the radiation pattern of the array of antennas.

10. The network node (21) of any one of Claims 1-9, further configured to: receive feedback from the at least one target; and adjust the beamforming parameters based at least upon the feedback.

11. The network node (21) of any one of Claims 1-10, further configured to: at least one of receive and determine a channel estimation of the at least one target area; and adjust the beamforming parameters based at least upon the channel estimation.

12. A method for a network node to communicate with at least one wireless device (WD) using an array of antennas, the method comprising: receiving (S58) an approximate position or direction of at least one target; and determining (S60) beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target.

13. The method of Claim 12, wherein the beam forming parameters are at least one of weights and digital or analog beam forming excitations.

14. The method of Claims 12 or 13 wherein determining the beam forming parameters for the array of antennas such that at least one null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises using a zero forcing function to calculate a null steering vector for the array of antennas that results in the at least one null or extensively attenuated area in the approximate direction of the at least one target.

15. The method of any one of Claims 12-14, comprising using a precoder to enforce the at least one null or extensively attenuated area in the at least one targets approximate direction.

16. The method of any one of Claims 12-15, further comprising receiving approximate positions or directions of a plurality of targets and determining the beam forming weights for the array of antennas such that a null or extensively attenuated area is created in the approximate direction of each of the plurality of targets.

17. The method of any one of Claims 12-16, further comprising setting a width of the null or extensively attenuated area.

18. The method of any one of Claims 12-17, further comprising mapping the at least one null or extensively attenuated area to at least one of a corresponding vertical tilt and a horizontal swivel value.

19. The method of any one of Claims 12-18, further comprising using a carrier frequency to configure the at least one null or extensively attenuated area.

20. The method of any one of Claims 12-19, wherein determining the beam forming weights for the array of antennas such that the null or extensively attenuated area is created in a radiation pattern of the array of antennas in the approximate direction of the at least one target comprises at least one of vertically tilting and horizontally swiveling the radiation pattern of the array of antennas.

21. The method of any one of Claims 12-20, further comprising: receiving feedback from the at least one target; and adjusting the beamforming parameters based at least upon the feedback.

22. The method of any one of Claims 12-21, further comprising: at least one of receiving and determining a channel estimation of the at least one target area; and adjusting the beamforming parameters based at least upon the channel estimation.