Indoor ceiling radio unit for distributed antenna system

Abstract

Methods, systems, and devices are disclosed for optimizing a radiation pattern of an indoor ceiling and / or wall mounted radio unit for a distributed antenna system / radio point system (DAS / RDS). According to one aspect, a method includes obtaining beamforming weights for generating a shaped radiation pattern that provides a same effective isotropic radiated power (EIPR) at a plurality of locations within a target cell; and applying the obtained beamforming weights to a signal directed to an array of antenna elements of a radio interface to generate the shaped radiation pattern.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to wireless communication, and in particular to radiation patterns for indoor radio units of a Distributed Antenna System / Radio Point System (DAS / RDS). BACKGROUND

[0002] As wireless networks such as the fifth generation (5G) networks developed according to the standards of the Third Generation Partnership Project (3GPP) are evolving, there is a requirement for radio units (RUs) with higher frequencies such as millimeter (mm) waves to support higher modulation bandwidths compared to earlier deployments. Currently, there is no satisfactory solution for the antennas and radio frequency (RF) front-ends for mm-wave access points for indoor applications. Phased array antennas have been proposed for outdoor use. However, for distributed solutions for indoor use, such as Distributed Antenna Systems (DAS) or Radio Point Systems (RDS), phased array arrangements have several drawbacks.

[0003] One drawback is that since several remote radio heads at several locations are combined into one common path to provide one instantaneous bandwidth supported by the baseband modem, each antenna head is pointing in a different direction when communicating with a wireless device (WD). As a result, the signal-to-noise ratio (SNR) in the overlapping cell area degrades compared to sub-6 GHz (below 6 GHz) products using fixed radiation pattern antennas. The reason is that with fixed patterns, the WD signal is received by several antennas, which is not the case for phased array antennas. Secondly, since phased array antennas are inherently directional, the antenna elements for mm-wave phased array systems need to search and track states to find and serve WDs in the covered cell. This adds complexity to the modem and increases the latency of the radio system. SUMMARY

[0004] Some embodiments advantageously provide methods and arrangements for antennas and for beamforming the radiation pattern of an indoor radio unit in a Distributed Antenna System / Radio Point System (DAS / RDS) that can be installed on a wall or a ceiling. To address the issues regarding distributed solutions and regarding ceiling and wall installations, for high frequencies such as mm-wave frequencies, a fixed radiation antenna pattern can be used.

[0005] The arrangements described herein provide a beamformed radiation pattern that provides the same effective isotropic radiated power (EIPR) across any location within the target cell, as shown in Figure 1 This way, the higher gain is concentrated in locations with more path loss.

[0006] Figure 2Antenna radiation patterns of patch antennas mainly used in current sub-6 GHz DAS / RDS systems and the proposed radiation pattern are shown. As depicted in the figure, in the proposed radiation pattern, the maximum gain is pushed towards the edges to compensate for the higher path loss present in the cell edge.

[0007] By using this pattern, the coverage of the network node radio can be increased while the radio uses a fixed pattern and the radiation direction of the radio head is always fixed. Thus, the signal-to-noise ratio (SNR) improvement over other solutions is attributed to the distributed antenna grouping utilized in distributed radio systems such as DAS and RDS systems, while upgrading to millimeter wave bands. In addition, the millimeter wave system described herein avoids searching and tracking the state of beam steering, and thereby avoids additional latency.

[0008] According to one aspect, a network node is configured to communicate with a wireless device, WD. The network node comprises processing circuitry configured to obtain beamforming weights for generating an shaped radiation pattern that provides a same effective isotropic radiated power, EIPR, at a plurality of locations within a target cell. The processing circuitry is further configured to apply the obtained beamforming weights to a signal directed to an array of antenna elements of a radio interface to generate the shaped radiation pattern.

[0009] According to this aspect, in some embodiments, the beamforming weights are obtained by using a pattern synthesis technique that causes an iterative reduction of a difference between a target radiation pattern and a resulting radiation pattern. In some embodiments, the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device. In some embodiments, the path loss is determined according to the following formula:

[0010]

[0011] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the shaped radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0012] According to another aspect, a method implemented in a network node comprises obtaining beamforming weights for generating a shaped radiation pattern that provides a same effective isotropic radiated power (EIPR) at a plurality of locations within a target cell; and applying the obtained beamforming weights to a signal directed to an array of antenna elements of a radio interface to generate the shaped radiation pattern.

[0013] According to this aspect, in some embodiments the beamforming weights are obtained by using a pattern synthesis technique that causes iteratively to reduce a difference between the target radiation pattern and the resulting radiation pattern. In some embodiments, the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device. In some embodiments, the path loss is determined according to the following formula:

[0014]

[0015] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the shaped radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0016] According to yet another aspect, there is provided a computer configured to determine an antenna design. The computer comprises processing circuitry configured to: specify a target radiation pattern that provides a same effective isotropic radiated power (EIRP) at a plurality of locations within a target cell; and minimize a cost function of a difference between the target radiation pattern and a resulting radiation pattern from a proposed design.

[0017] According to this aspect, in some embodiments the cost function is based at least in part on an excitation of an element of the antenna. In some embodiments, the cost function is based at least in part on a distance and / or size of an element of the antenna. In some embodiments, the cost function is based at least in part on a path loss determination. In some embodiments, the path loss determination is given by the following formula:

[0018]

[0019] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient.

[0020] According to another aspect, there is provided a method of designing an antenna. The method comprises: specifying a target radiation pattern that provides a same effective isotropic radiated power (EIRP) at a plurality of locations within a target cell; and minimizing a cost function of a difference between the target radiation pattern and a resulting radiation pattern from a proposed design.

[0021] According to this aspect, in some embodiments, the cost function is based at least in part on excitation of elements of the antenna. In some embodiments, the cost function is based at least in part on distance and / or size of elements of the antenna. In some embodiments, the cost function is based at least in part on a path loss determination. In some embodiments, the path loss determination is given by the following:

[0022]

[0023] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient. BRIEF DESCRIPTION OF DRAWINGS

[0024] A more complete understanding of the present embodiments and the attendant advantages and features thereof will be more fully understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0025] Figure 1 shows a beamformed radiation pattern that provides the same effective isotropic radiated power (EIPR) at any location within the target cell;

[0026] Figure 2 shows an antenna radiation pattern of a patch antenna (top pattern) that is mainly used in current sub-6GHz DAS / RDS systems and the proposed radiation pattern (bottom pattern);

[0027] Figure 3 shows the radiated power within the target cell that is shaped to provide nearly the same EIRP at every location within the cell;

[0028] Figure 4 is a schematic diagram of an exemplary network architecture showing a communication system connected via intermediate networks to a host computer in accordance with the principles of the present disclosure;

[0029] Figure 5 is a block diagram of a network node in communication with a wireless device over at least partially wireless connections in accordance with some embodiments of the present disclosure;

[0030] Figure 6 is a flowchart of an exemplary process in a network node for generating an optimized radiation pattern for an indoor radio unit such as for wall and / or ceiling installation for a distributed antenna system / radio point system (DAS / RDS);

[0031] Figure 7 is a flowchart of an exemplary process for designing an antenna having an effective isotropic radiated power (EIPR) at multiple locations within a target cell;

[0032] Figure 8 is a plot of path loss versus cell radius;

[0033] Figure 9 is a plot of average path loss angle versus ceiling height;

[0034] Figure 10 shows a cross section of an antenna pattern symmetrical along the z-axis to enable to shape a circular cell; and

[0035] Figure 11 is a diagram of an array of antennas for beamforming according to the principles set forth herein. DETAILED DESCRIPTION

[0036] Before one or more exemplary embodiments are described in detail, it is to be understood that the inventive concepts as well as the apparatuses and processes described herein are not limited in their application to the details of construction, the arrangements of components, and the arrangement of steps set forth in the following description or illustrated in the drawings. The embodiments are capable of implementation in other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and not of limitation. Accordingly, the use of "including" and "comprising" and variations thereof herein is intended to be equivalent to the term "consisting of" to mean the inclusion of the recited item or items and the exclusion of items that are not recited. Furthermore, where a definition or use of a term in an incorporated reference is inconsistent or inconsistent with the definition of that term in the present disclosure, the definition of that term in the present disclosure shall prevail.

[0037] As used herein, relational terms, such as "first" and "second," "top" and "bottom," and the like, can 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" and / or "comprising," when used in this specification, 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.

[0038] In the embodiments described herein, "communicate" and like terms can be used to indicate electrical or data communication, which can be implemented using any operable connection, such as physical contacts, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling. One skilled in the art will recognize that a plurality of components can interoperate and modifications and variations of electrical and data communication are possible.

[0039] In some embodiments described herein, the term "coupled" or "connected" or similar terms can be used herein to indicate a connection, although not necessarily directly, and can include wired and / or wireless connections.

[0040] The term "network node" used herein can be any kind of network node included in a radio network, which can further comprise any of: a base station (BS), a radio base station, a base transceiver station (BTS), a base station controller (BSC), a radio network controller (RNC), a gNodeB (gNB), an evolved Node B (eNB or eNodeB), a Node B, a multi- standard radio (MSR) radio node such as a MSR BS, a multi-cell / multicast coordination entity (MCE), an integrated access and backhaul (IAB) node, a relay node, a donor node controlling relays, a radio access point (AP), a transmission point, a transmission node, a remote radio unit (RRU) a remote radio head (RRH), a core network node (e.g., a mobile management entity (MME), a self-organizing network (SON) node, a coordinating node, a positioning node, an MDT node, etc.), an external node (e.g., a third party node, a node outside current network), a node in a distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. A network node can also include a test equipment. The term "radio node" used herein can also be used to denote a wireless device (WD), such as a wireless device (WD) or a radio network node.

[0041] In some embodiments, the non-limiting terms wireless device (WD) or user equipment (UE) can be used interchangeably. A WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as a wireless device (WD). The WD can also be a radio communication apparatus, target device, device-to-device (D2D) WD, machine-type wireless device, or machine-to-machine (M2M) WD, low-cost and / or low-complexity WD, sensor-equipped WD, tablet, mobile terminal, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongle, customer premises equipment (CPE), an Internet-of-Things (IoT) device, or a Narrowband IoT (NB-IoT) device, etc.

[0042] Also, in some embodiments, the generic term "radio network node" is used. It can be any kind of radio network node, which can comprise any of: a base station, a radio base station, a base transceiver station, a base station controller, a network controller, RNC, eNodeB, NodeB, gNB, Multi-cell / multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

[0043] It is to be noted that although terminology from one particular wireless system, such as e.g. the 3GPP LTE and / or New Radio (NR), can be used in this disclosure, this does not in any way aim to limit the scope of the disclosure to only the aforementioned system. Other wireless systems, including but not limited to Wideband Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), can also benefit from exploiting the ideas covered within this disclosure.

[0044] It is further to be noted that functions described herein as being performed by a wireless device or a network node can be distributed in a number of wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network nodes and wireless devices described herein are not limited to being performed by a single physical device, and can in fact be distributed among several physical devices.

[0045] 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.

[0046] Because of the existing output power limitations at millimeter wave frequencies or higher frequencies, omni-directional or directional single antenna radiation patterns, such as patch antennas, face constraints. These constraints can be mitigated by employing an array of antennas in order to obtain a desired antenna radiation pattern. However, such an array should provide sufficient power across locations within an area served by a cell in order to be able to provide power sufficient to exceed a receiver sensitivity of a wireless device (WD). Also, such a gain obtained can help the sensitivity of a receiver of an access point for uplink.

[0047] Accordingly, embodiments provide a radiation pattern for an indoor ceiling and / or wall mounted radio unit of a Distributed Antenna System / Radio Point System (DAS / RDS). The solution described herein can be achieved by arranging, i.e. optimizing the radiation power of the antenna in such a way that it minimizes the radiation power at angles (Ɵ) outside the target cell. The radiation power within the target cell can be shaped, e.g. as shown in Figure 3 Figure 1, to provide almost the same EIRP at every location within the cell. In some embodiments, this results in an antenna pattern (radiation pattern) where the gain increases with distance from the axis of symmetry of the pattern.

[0048] Referring again to the drawings, wherein like reference numerals refer to like elements throughout, Figure 4 a schematic overview of a communication system 10 according to embodiments, such as a 3GPP-type cellular network that can support standards such as LTE and / or NR (5G), is shown in Figure 1, which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (collectively referred to as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area that corresponds to a cell 18a, 18b, 18c (collectively referred to as cells 18). A cell 18 can also be referred to herein as a coverage area. One or more cells can be indoors. Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in the cell 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in the cell 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) 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 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system can include many more WDs 22 and network nodes 16.

[0049] Also, it is contemplated that a WD 22 can be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 can have dual connectivity with an LTE capable network node 16 and a same or different network node 16 that supports NR. As an example, a WD 22 can be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN.

[0050] The network node 16 (eNB or gNB) is configured to comprise a cell- shaped beamformer 32 configured to apply beamforming weights to signals directed to an array 80 of antenna elements of a radio interface to generate a shaped radiation pattern that provides the same effective isotropic radiated power (EIRP) at multiple locations within a target cell. In some embodiments, the cell-shaped beamformer 32 can be configured to minimize a cost function of the difference between a target radiation pattern and a resulting radiation pattern from a proposed design.

[0051] Reference will now be made to Figure 5 Example implementations of the WD 22, network node 16, and host computer 24 discussed in the preceding paragraphs will now be described with reference to

[0052] The communication system 10 includes a network node 16 provided in a communication system 10 and comprising hardware 38, which can be or include a computer, the hardware 38 enabling the network node 16 to communicate with the WD 22. The hardware 38 can include a radio interface 42 for set- ting up and maintaining at least a wireless connection 74 with a WD 22 located in a cell 18 served by the network node 16. The radio interface 42 can be formed as or can include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 42 includes an antenna 43, which can comprise an array 80 of antenna elements, or can be a single antenna element or antenna, to radiate and receive electromagnetic waves carrying signals.

[0053] In the illustrated embodiment, the hardware 38 of the network node 16 further includes processing circuitry 46. The processing circuitry 46 can include a processor 48 and memory 50. In particular, the processing circuitry 46 can include integrated circuits, such as one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Arrays) and / or ASICs (Application-Specific Integrated Circuits), adapted to execute instructions, in addition to or instead of a processor such as a central processing unit. The processor 48 can be configured to access (e.g., write to and / or read from) memory 50 that can include any kind of volatile and / or nonvolatile storage and / or storage media, such as cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read Only Memory) and / or optical storage and / or EPROM (Erasable Programmable Read Only Memory).

[0054] Thus, the network node 16 further has software 44 stored internally, e.g., in memory 50, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible via an external connection through the network node 16. The software 44 can be executable by the processing circuitry 46. The processing circuitry 46 can 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 the network node 16. The processor 48 corresponds to one or more processors 48 for performing network node 16 functions described herein. The memory 50 is configured to store data, programmatic software code, and / or other information described herein. In some embodiments, the software 44 can include instructions executable by the processor 48 and / or processing circuitry 46, that, when executed, cause the processor 48 and / or processing circuitry 46 to carry out processes described herein with respect to the network node 16. For example, the processing circuitry 46 of the network node 16 can include a cell-tilted beamformer 32 configured to apply beamforming weights to signals of an array 80 of antenna elements directed to a radio interface to generate a shaped radiation pattern, where the shaped radiation pattern provides a same effective isotropic radiated power (EIRP) at multiple locations within a target cell. In some embodiments, the cell-tilted beamformer 32 can be configured to minimize a cost function of a difference between a target radiation pattern and a resulting radiation pattern from a proposed design.

[0055] The communication system 10 further includes the WD 22 already referred to. The WD 22 can have hardware 60, which can include a radio interface 62 configured to set up and maintain a wireless connection 74 with a network node 16 serving a cell 18 in which the WD 22 is currently located. The radio interface 62 can be formed as or can include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 62 includes an array of antennas 63 to radiate and receive electromagnetic waves carrying signals.

[0056] The hardware 60 of the WD 22 further includes processing circuitry 64. The processing circuitry 64 can include a processor 66 and memory 68. In particular, the processing circuitry 64 can include 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, in particular, computer program instructions. The processor 66 can be configured to access (e.g., write to and / or read from) memory 68, which can include any kind of volatile and / or nonvolatile storage, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read Only Memory) and / or optical storage and / or EPROM (Erasable Programmable ROM).

[0057] Thus, the WD 22 can further include software 70, which is stored in, for example, memory 68 at the WD 22, or stored in external storage to which the WD 22 has access (e.g., on a database, a storage array, a network storage device, etc.). The software 70 can be executable by the processing circuitry 64. The software 70 can include a client application 72. The client application 72 can be operable to provide a service to a human or non-human user via the WD 22.

[0058] The processing circuitry 64 can 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 the WD 22. The processor 66 corresponds to one or more processors 66 for performing WD 22 functions described herein. The WD 22 includes memory 68 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 70 and / or the client application 72 can include instructions that, when executed by the processor 66 and / or processing circuitry 64, cause the processor 66 and / or processing circuitry 64 to perform the processes described herein with respect to the WD 22.

[0059] In some embodiments, the inner workings of the network node 16 and WD 22 can be as shown in FIG. 13 and independently, the surrounding network topology can be as in Figure 5 . Figure 4 .

[0060] The wireless connection 74 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. More specifically, the teachings of some of these embodiments can improve data rates, latency, and / or power consumption and, thereby, provide benefits such as reduced user waiting time, relaxed restrictions on file size, better responsiveness, extended battery lifetime, etc. In some embodiments, a measurement procedure can be provided for the purpose of monitoring data rates, latency, and other factors on which these one or more embodiments improve.

[0061] Although Figure 4 And Figure 5 Various "units" such as the cell-specific beamformer 32 are shown within a corresponding processor, but it is envisioned that the units can be implemented such that parts of the units are stored in a corresponding memory within the processing circuitry. In other words, the units can be implemented in hardware, or a combination of hardware and software within the processing circuitry.

[0062] Figure 6 is a flowchart of an exemplary procedure for an optimized radiation pattern, compared to other solutions, of an indoor ceiling and / or wall mounted radio unit for a distributed antenna system / radio point system (DAS / RDS) in a network node 16. One or more blocks described herein can be performed by one or more elements of the network node 16, such as by one or more of the processing circuitry 46 (including the cell-specific beamformer 32), the processor 48, and / or the radio interface 42. The network node 16 is configured to, such as via the processing circuitry 46 and / or the processor 48 and / or the radio interface 42, obtain beamforming weights for generating a shaped radiation pattern that provides the same effective isotropic radiated power (EIRP) at multiple locations within a target cell (block SI 00). The procedure further includes applying the obtained beamforming weights to signals directed to an array of antenna elements of the radio interface to generate the shaped radiation pattern (block S102).

[0063] Figure 7is a flowchart of an exemplary process for designing an antenna according to the principles set forth herein. The process can be performed by processing circuitry. The processing circuitry can comprise a processor and a memory. In particular, in addition to or instead of a processor, such as a central processing unit, and a memory, the processing circuitry can comprise an 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 Circuit) adapted to execute instructions. The processor can be configured to access (e.g. write to and / or read from) memory, which can comprise any kind of volatile and / or nonvolatile storage, e.g. cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read Only Memory) and / or optical storage and / or EPROM (Erasable Programmable ROM). The process comprises specifying a target radiation pattern providing the same effective isotropic radiated power (EIPR) at multiple locations within a target cell (block S104) and minimizing a cost function of a difference between the target radiation pattern and a radiation pattern resulting from a proposed design (block S106).

[0064] Having described the general process flow of the arrangements of the present disclosure and provided examples of hardware and software arrangements for implementing the processes and functions of the present disclosure, the following sections provide details and examples of arrangements for optimizing the radiation pattern of an indoor ceiling and / or wall mounted radio unit with a radiation pattern for a distributed antenna system / radio point system (DAS / RDS).

[0065] The method for a beamforming strategy within a cell 18 (i.e. coverage area) can be based on the path loss between the access point and the wireless device location. The target cell 18 can have a circular shape and from the center to the periphery, the path loss can be as depicted in Figure 8 A suggested path loss for indoors is as follows:

[0066]

[0067] wherein, d is the separation distance (m) between the network node 16 and the wireless device 22, f is the frequency (MHz), and N is the distance power loss coefficient. In some models, the path loss can increase with the distance from the center axis.

[0068] Table 1 shows examples of N coefficients for different frequency ranges from line of sight and non-line of sight, where the superscript "(12)" designates the cell content, where the upper number is for line of sight (LoS) cases and the lower number is for non-LoS cases.

[0069] Table 1

[0070]

[0071] For example, calculate the path loss for 28 GHz and three different ceiling heights (3, 6, and 9 meters), such as Figure 8 As shown in the diagram. A path loss curve is plotted for cell 18 with a diameter of 20 meters when the antenna is placed at the center of cell 18. Parameter N is selected for a non-line-of-sight and office application, which may be the worst-case scenario in terms of path loss.

[0072] like Figure 8 As shown, in some embodiments, path loss increases away from the center. This suggests increasing the antenna array gain in the same way as increasing path loss. Therefore, the gain can be designed to compensate for path loss, and a uniform EIRP can be provided across target cell 18. Figure 9 The diagram shows the Ɵ range when the ceiling height is increased to achieve uniform EIRP coverage of 20mm cells. (As shown in...) Figure 8 and Figure 9 As observed, for low-ceiling deployments, in some examples, path loss variation and Ɵ range are increased.

[0073] During the implementation phase, if modifications are desired or necessary to be applied to the depicted curves, they can be measured on-site. Figure 8 The relevant curves.

[0074] Figure 10 An example pattern shown is symmetric about the z-axis and shaped to serve a circular cell. Several possible antenna pattern synthesis techniques exist to achieve such a pattern, which can be implemented by a processor (such as processor 48 and / or beamformer 32). It will be understood that pattern synthesis can be performed by a first processor, and the resulting beamforming weights can then be passed to processor 48 for beamforming, for example, by beamformer 32. Figure 11 One arrangement shown is to use an array 80 of antenna elements as antenna 43. Figure 11 The antenna array 80 shown is a two-dimensional array. A three-dimensional array can be implemented. Using this array, the proposed pattern can be the target pattern for the optimization process. The elements used for the array can then be selected. The antenna elements can be the same or different. For example, the antenna elements can have different sizes and / or different shapes. The cost function can then be defined as subtracting the target pattern from the resulting pattern produced by applying the proposed set of signals to the selected array elements. The array and the cost function can have several variables, such as the amplitude and phase applied to each element, the distance between antennas in the array, the size of the elements in the array, etc. Optimization tools can be used to minimize the error of the cost function and achieve an acceptable error range in the target radiation pattern.

[0075] Thus, a fixed radiation pattern for indoor ceiling and / or wall mounted applications suitable for utilization in distributed radio systems such as DAS and RDS systems is provided. The pattern can extend the coverage of a cell compared to an omni pattern or a regular directional pattern such as the pattern of a regular patch antenna. Thus, the pattern can be useful for high frequency applications such as millimeter wave applications with power amplifier limitations.

[0076] By building on the fixed radiation pattern concept, the solution described herein provides an alternative to more complex solutions involving phased array antennas and analog / digital beamforming and beam steering. Some solutions provide design flexibility and simplify current modems (digital units) for higher frequency ranges. It is noted that there is a difference between regular beamforming involving beam steering and the beamforming (shaping) described herein. The beams formed in some embodiments described herein do not take the form of steered regular beams, but rather occupy a fixed wide energy distribution of the cell according to a desired fixed target pattern. The fixed wide distribution is not omni, but can be shaped to provide gain against path loss in the cell.

[0077] According to one aspect, a network node 16 is configured to communicate with a wireless device WD 22. The network node 16 comprises processing circuitry 46 configured to obtain beamforming weights for generating a shaped radiation pattern that provides a same effective isotropic radiated power EIRP at a plurality of locations within a target cell. The processing circuitry 46 is further configured to apply the obtained beamforming weights to signals of an array 80 of antenna elements of an antenna 43 pointed at a radio interface 42 to generate the shaped radiation pattern.

[0078] According to this aspect, in some embodiments, the beamforming weights are obtained by using a pattern synthesis technique implemented by the processing circuitry 46 that causes an iterative reduction of a difference between a target radiation pattern and a resulting radiation pattern. In some embodiments, the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device. In some embodiments, the path loss is determined according to the following formula:

[0079]

[0080] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the shaped radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0081] According to another aspect, a method implemented in a network node 16 includes obtaining, via processing circuitry 46, beamforming weights for generating a shaped radiation pattern that provides a same effective isotropic radiated power (EIRP) at multiple locations within a target cell, and applying, via a radio interface 42, the obtained beamforming weights to a signal directed to an array 80 of antenna elements of the radio interface 42 to generate the shaped radiation pattern.

[0082] According to this aspect, in some embodiments, the beamforming weights are obtained by using a pattern synthesis technique that causes an iterative reduction in a difference between a target radiation pattern and a resulting radiation pattern. In some embodiments, the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device. In some embodiments, the path loss is determined according to the following equation:

[0083]

[0084] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the shaped radiation pattern is axisymmetric about an axis and has a gain that increases as distance from the axis increases.

[0085] According to yet another aspect, a computer configured to determine an antenna design is provided. Hardware 38 (e.g., a computer) includes processing circuitry 46 configured to specify a target radiation pattern that provides a same effective isotropic radiated power (EIRP) at multiple locations within a target cell, and minimize a cost function of a difference between the target radiation pattern and a resulting radiation pattern from a proposed design.

[0086] According to this aspect, in some embodiments, the cost function is based at least in part on excitation of elements of the antenna 43. In some embodiments, the cost function is based at least in part on distance and / or size of elements of the antenna 43. In some embodiments, the cost function is based at least in part on a path loss determination. In some embodiments, the path loss determination is given by the following equation:

[0087]

[0088] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient.

[0089] According to another aspect, a method of designing an antenna 43 is provided. The method comprises: specifying a target radiation pattern that provides a same effective isotropic radiated power (EIPR) at a plurality of locations within a target cell; and minimizing, via processing circuitry 46, a cost function of a difference between the target radiation pattern and a resulting radiation pattern from a proposed design.

[0090] According to this aspect, in some embodiments, the cost function is based at least in part on excitations of elements of the antenna 43. In some embodiments, the cost function is based at least in part on distances and / or sizes of elements of the antenna 43. In some embodiments, the cost function is based at least in part on a path loss determination. In some embodiments, the path loss determination is given by:

[0091]

[0092] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient.

[0093] According to one aspect, a network node 16 configured to communicate with a wireless device (WD) 22 comprises a radio interface 42 and / or processing circuitry 46 configured to obtain beamforming weights for generating a shaped radiation pattern that provides a same effective isotropic radiated power (EIPR) at a plurality of locations within a target cell 18. The network node 16 further applies, via a cell- shaped beamformer 32, the obtained beamforming weights to a signal directed to an array of antenna elements of an antenna 43 forming the radio interface 42 to generate the shaped radiation pattern.

[0094] According to this aspect, in some embodiments, the beamforming weights are obtained by using a pattern synthesis technique that causes iteratively to reduce a difference between the target radiation pattern and a resulting radiation pattern. In some embodiments, the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device. In some embodiments, the path loss is determined according to:

[0095]

[0096] wherein, d is a separation distance between the network node 16 and the wireless device 22, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the shaped radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0097] According to another aspect, a method comprises obtaining, via processing circuitry 46, beamforming weights for generating an apertured radiation pattern that provides a same effective isotropic radiated power (EIRP) at multiple locations within a target cell 18. The method further comprises applying, via the processing circuitry 46 and / or the radio interface 42, the obtained beamforming weights to a signal directed to an array of antenna elements forming an antenna 43 of the radio interface 42 to generate the apertured radiation pattern.

[0098] According to this aspect, in some embodiments, the beamforming weights are obtained by using a pattern synthesis technique implemented by the processing circuitry 46 that causes an iterative reduction of a difference between a target radiation pattern and a resulting radiation pattern. In some embodiments, the beamforming weights are determined, via the processing circuitry 46, based at least in part on a path loss between the network node 16 and the wireless device 22. In some embodiments, the path loss is determined according to:

[0099]

[0100] wherein, d is a separation distance between the network node 16 and the wireless device 22, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the apertured radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0101] According to yet another aspect, a method of designing an antenna 43 comprises specifying a target radiation pattern that provides a same effective isotropic radiated power (EIRP) at multiple locations within a target cell 18 and minimizing a cost function of a difference between the target radiation pattern and a resulting radiation pattern from a proposed design.

[0102] According to this aspect, in some embodiments, the cost function is based at least in part on an excitation of elements of the antenna 43. In some embodiments, the cost function is based at least in part on a distance and / or size of elements of the antenna 43. In some embodiments, the cost function is based at least in part on a path loss determination. In some embodiments, the path loss determination is given by:

[0103]

[0104] wherein, d is a separation distance between the network node 16 and the wireless device 22, f is a frequency, and N is a distance power loss coefficient. In some embodiments, the target radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0105] Some embodiments include the following embodiments:

[0106] Embodiment A1. A network node configured to communicate with a wireless device (WD), the network node configured to, and / or comprising a radio interface and / or comprising processing circuitry configured to:

[0107] obtain beamforming weights for generating an shaped radiation pattern that provides a same effective isotropic radiated power (EIRP) at a plurality of locations within a target cell; and

[0108] apply the obtained beamforming weights to signals directed to an array of antenna elements of the radio interface to generate the shaped radiation pattern.

[0109] Embodiment A2. The network node of embodiment A1, wherein the beamforming weights are obtained by using a pattern synthesis technique that causes an iterative reduction in a difference between a target radiation pattern and a resulting radiation pattern.

[0110] Embodiment A3. The network node of any of embodiments A1 and A2, wherein the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device.

[0111] Embodiment A4. The network node of embodiment A3, wherein the path loss is determined according to:

[0112]

[0113] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient.

[0114] Embodiment A5. The network node of any of embodiments A1-A4, wherein the shaped radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0115] Embodiment B1. A method implemented in a network node, the method comprising:

[0116] obtaining beamforming weights for generating an shaped radiation pattern that provides a same effective isotropic radiated power (EIRP) at a plurality of locations within a target cell; and

[0117] applying the obtained beamforming weights to signals directed to an array of antenna elements of the radio interface to generate the shaped radiation pattern.

[0118] Embodiment B2. The method of Embodiment B1, wherein the beamforming weights are obtained by using a pattern synthesis technique that causes the difference between the target radiation pattern and the resulting radiation pattern to be iteratively reduced.

[0119] Embodiment B3. The method of any of Embodiments B1 and B2, wherein the beamforming weights are determined based at least in part on a path loss between the network node and the wireless device.

[0120] Embodiment B4. The method of Embodiment B3, wherein the path loss is determined according to:

[0121]

[0122] wherein, d is a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient.

[0123] Embodiment B5. The method of any of Embodiments B1-B4, wherein the shaped radiation pattern is axisymmetric and has a gain that increases with increasing distance from the axis.

[0124] Embodiment C1. A method of designing an antenna, the method comprising:

[0125] specifying a target radiation pattern that provides a same effective isotropic radiated power (EIRP) at a plurality of locations within a target cell; and

[0126] minimizing a cost function of a difference between the target radiation pattern and a resulting radiation pattern from the proposed design.

[0127] Embodiment C2. The method of Embodiment C1, wherein the cost function is based at least in part on an excitation of an element of the antenna.

[0128] Embodiment C3. The method of any of Embodiments C1 and C2, wherein the cost function is based at least in part on a distance and / or size of an element of the antenna.

[0129] Embodiment C4. The method of any of Embodiments C1-C3, wherein the cost function is based at least in part on a path loss determination.

[0130] Embodiment C5. The method of Embodiment C4, wherein the path loss determination is given by:

[0131]

[0132] wherein, dis a separation distance between the network node and the wireless device, f is a frequency, and N is a distance power loss coefficient.

[0133] Embodiment C6. The method of any of embodiments C1-C5, wherein the target radiation pattern is axisymmetric about an axis and has a gain that increases with increasing distance from the axis.

[0134] Those skilled in the art will appreciate that the concepts described herein can be embodied as a method, data processing system, computer program product, and / or computer storage media storing executable computer program. Thus, the concepts described herein can 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 can be performed by, and / or associated to, a corresponding module, which can be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure can take the form of a computer program product on a tangible computer readable storage medium having computer program code embodied in the medium, which can be executed by a computer. Any suitable tangible computer readable medium can be utilized including a hard disk, CD-ROM, electronic storage, optical storage or magnetic storage.

[0135] 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 can be provided to a processor of a general purpose computer (with the result that a special purpose computer is created), a 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.

[0136] These computer program instructions can 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 instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0137] The computer program instructions can 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.

[0138] It is to be understood that the functions / acts noted in the blocks can occur out of the order noted in the operational illustrations. For example, two blocks noted in succession can in fact be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some diagrams can include arrows on communication paths to show a primary direction of communication, it is to be understood that communication can occur in the opposite direction to the arrows.

[0139] Computer program code for carrying out operations of the concepts described herein can 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 can also be written in conventional procedural programming languages, such as the "C" programming language. The program code can 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 can be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0140] Many different embodiments have been disclosed herein with respect to the above description and the accompanying drawings. It will be understood that each of the combinations and permutations of these embodiments, as well as each of the individual elements

[0141] Abbreviations that can be used in the preceding description include:

[0142] Abbreviation Explanation

[0143] DAS Distributed Antenna System

[0144] EIPR Effective Isotropic Radiated Power

[0145] RDS Radio Point System

[0146] RU Radio Unit

[0147] SNR signal-to-noise ratio

[0148] UE user equipment

[0149] WD wireless device

[0150] Those skilled in the art will realize that the embodiments described herein are not limited to the details of the foregoing description, and are capable of further modifications and variations, without departing from the scope of the appended claims.

Claims

1. A network node (16) configured to communicate with a wireless device (22), the network node (16) including processing circuitry (46) configured to: Obtain beamforming weights for generating a shaped radiation pattern that provides the same Effective Isotropic Radiated Power (EIPR) at multiple locations within the target cell; and The obtained beamforming weights are applied to the signal of an array (80) of antenna elements pointing to the radio interface to generate the shaped radiation pattern. in, The shaped radial pattern is symmetrical about the axis and has a gain that increases with increasing distance from the axis.

2. The network node (16) as described in claim 1, wherein, The beamforming weights are obtained by using a pattern synthesis technique, which enables iterative reduction of the difference between the target radiation pattern and the resulting radiation pattern.

3. The network node (16) as described in any one of claims 1 and 2, wherein, The beamforming weights are determined at least in part based on the path loss between the network node (16) and the wireless device (22).

4. The network node (16) as described in claim 3, wherein, The path loss is determined according to the following formula: Ltotal=20log10 f+N log10 d–28dB Where d is the separation distance between the network node (16) and the wireless device (22), f is the frequency, and N is the distance power loss coefficient.

5. A method implemented in a network node (16) configured to communicate with a wireless device (22), the method comprising: (S100) Obtain beamforming weights for generating a shaped radiation pattern that provides the same effective isotropic radiated power (EIPR) at multiple locations within the target cell. as well as The obtained beamforming weights are applied (S102) to the signal of the array (80) of antenna elements pointing to the radio interface to generate the shaped radiation pattern. The shaped radial pattern is symmetrical about the axis and has a gain that increases with the distance from the axis.

6. The method of claim 5, wherein, The beamforming weights are obtained by using a pattern synthesis technique, which enables iterative reduction of the difference between the target radiation pattern and the resulting radiation pattern.

7. The method as described in any one of claims 5 and 6, wherein, The beamforming weights are determined at least in part based on the path loss between the network node (16) and the wireless device (22).

8. The method of claim 7, wherein, The path loss is determined according to the following formula: Ltotal=20log10 f+N log10 d–28dB Where d is the separation distance between the network node (16) and the wireless device (22), f is the frequency, and N is the distance power loss coefficient.

9. A computer (38) configured to determine the design of an antenna, the computer (38) including processing circuitry (46) configured to: A specified target radiation pattern is provided, which provides the same Effective Isotropic Radiated Power (EIPR) at multiple locations within a target cell; and The cost function that minimizes the difference between the target radiation pattern and the radiation pattern obtained from the proposed design is used. in, The proposed design includes selecting antenna elements for the array, and the resulting radiation pattern includes the pattern generated by applying a proposed set of signals to the selected array elements. The target radiation pattern is symmetrical about an axis and has a gain that increases with the distance from the axis.

10. The computer (38) as claimed in claim 9, wherein, The cost function is at least partially based on the excitation of the antenna's elements.

11. The computer (38) as claimed in any one of claims 9 and 10, wherein, The cost function is at least in part based on the distance and / or size of the antenna elements.

12. The computer (38) as claimed in any one of claims 9 and 10, wherein, The cost function is determined at least in part based on path loss.

13. The computer (38) as claimed in claim 12, wherein, The path loss is determined by the following formula: Ltotal=20log10 f+N log10 d–28dB Where d is the separation distance between the network node (16) and the wireless device (22), f is the frequency, and N is the distance power loss coefficient.

14. A method for designing an antenna, the method comprising: Designate (S104) a target radiation pattern that provides the same effective isotropic radiated power (EIPR) at multiple locations within the target cell; as well as The cost function that minimizes the difference between the target radiation pattern and the radiation pattern obtained from the proposed design is minimized (S106). The proposed design includes selecting antenna elements for the array, and the radiation pattern resulting from the proposed design includes the resulting pattern generated by applying a proposed set of signals to the selected array elements. The target radiation pattern is symmetrical about an axis and has a gain that increases with the distance from the axis.

15. The method of claim 14, wherein, The cost function is at least partially based on the excitation of the antenna's elements.

16. The method of any one of claims 14 and 15, wherein, The cost function is at least in part based on the distance and / or size of the antenna elements.

17. The method of any one of claims 14 and 15, wherein, The cost function is determined at least in part based on path loss.

18. The method of claim 17, wherein, The path loss is determined by the following formula: Ltotal=20log10 f+N log10 d–28dB Where d is the separation distance between the network node (16) and the wireless device (22), f is the frequency, and N is the distance power loss coefficient.

Images