Fixed wireless access-assisted beam squint compensation in cellular systems

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present invention relates to fixed wireless access-assisted beam squint compensation in cellular system. The method includes receiving, by CPE (403), RF signals from a plurality of UE (405) in the FWA-assisted cellular system. Further, the method includes determining compensation vector over different frequency sub-bands associated with the at least one UE (405) over which the CPE (403) is preparing the RF signals to be transmitted. Further, the method includes steering beam of the CPE (403) in direction towards network apparatus (401) by performing beam squint compensation in uplink based on the compensation vector on the different frequency sub-bands. Further, the method includes transmitting the RF signals received from the plurality of UEs (405) to the network apparatus (401) over the different frequency sub-bands.

Description

FIXED WIRELESS ACCESS-ASSISTED BEAM SQUINT COMPENSATION IN CELLULAR SYSTEMS

[0001] The proposed embodiments relate to wireless communication system. More particularly, the present disclosure relates to fixed wireless access-assisted beam squint compensation in cellular system.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] In recent years, the demand for radio spectrum in wireless communication has skyrocketed, driven by the rapid adoption of new technologies. The rise of 5G, the next-generation cellular network, is a prime example of this trend. To deliver on its promises of high performance, 5G requires several GHz of spectrum. Unfortunately, the spectrum below 6 GHz is no longer enough to meet these demands, pushing the industry to explore higher frequency bands.

[0009] To address this, 5G has turned to the millimeter wave (mmWave) range of the radio spectrum, also known as Frequency Range 2 (FR2). While mmWave frequencies offer impressive advantages, such as high data rates and large bandwidths, they also come with challenges. One issue is the higher path-loss at these frequencies, which limits coverage. To overcome this, beamforming techniques are employed. Beamforming uses antenna arrays to focus signals in specific directions, enhancing coverage, and data throughput.

[0010] There are three main types of beamforming: analog, digital, and hybrid.

[0011] Analog beamforming uses a single radio frequency (RF) chain to adjust the phase and amplitude of signals via analog phase shifters, creating directional beams. While efficient for single-beam transmission, it's less flexible and struggles with handling multiple data streams.

[0012] Digital beamforming is more advanced, using multiple RF chains and baseband processors to independently control signals at each antenna element. This allows for multiple beams and spatial multiplexing, offering greater flexibility and performance―though it comes at a higher cost and power usage.

[0013] Hybrid beamforming strikes a balance between the two, combining a reduced number of RF chains with a mix of analog and digital components. This approach aims to provide high performance while keeping costs and power consumption in check, making it ideal for 5G's mmWave communications.

[0014] Fixed Wireless Access (FWA) is another application of wireless technology, designed to deliver broadband internet to homes and businesses using fixed wireless links. FWA employs technologies like LTE, 5G NR (New Radio), and Wi-Fi to provide connectivity. It uses various spectrum bands, including sub-6 GHz, mmWave, and unlicensed bands, to deliver high-speed internet. Sub-6 GHz FWA offers wider coverage but lower speeds, while mmWave-based FWA delivers ultra-high speeds but has limited coverage.

[0015] FWA also faces its own challenges, such as the need for a clear line of sight (LoS) between the network apparatus and the user's location. Signal interference from obstacles like buildings and trees, especially at higher frequencies, and sensitivity to weather conditions further complicate its performance.

[0016] A specific issue with FWA in mmWave bands is beam squinting. This occurs when the beam's direction shifts with frequency due to phase shifter limitations, large antenna arrays, or variations in Subcarrier Spacing (SCS). Beam squinting can degrade the quality of the internet connection for users.

[0017] Thus, it is desired to address the above-mentioned disadvantages, issues, or other shortcomings, or at least provide a useful alternative.

[0018] The principal object of the embodiments herein relates to fixed wireless access-assisted beam squint compensation in cellular systems.

[0019] Another object of the present invention is to detect, calculate, and compensate beam squinting for FWA-assisted cellular systems.

[0020] Yet another object of the invention is to generate a compensation vector based on the beamforming vector for performing the beam compensation.

[0021] Yet another object of the present invention is to include a beam squint indicator (BSI) corresponding to SRS for a beam at Customer Premises Equipment (CPE).

[0022] In an aspect, the objectives are achieved by providing a method for compensating beam squint in an FWA-assisted cellular system. The method includes receiving by a CPE RF signals from a plurality of User Equipment (UE) in the FWA-assisted cellular system. Further, the method includes determining by the CPE a compensation vector over different frequency sub-bands associated with the at least one UE over which the CPE is preparing the RF signals to be transmitted. Further, the method includes steering by the CPE a beam of the CPE in a direction towards a network apparatus by performing a beam squint compensation in an uplink based on the compensation vector on the different frequency sub-bands. Further, the method includes transmitting by the CPE the RF signals received from the plurality of UEs to the network apparatus over the different frequency sub-bands.

[0023] In another aspect, the objectives are achieved by providing a CPE for compensating beam squint in an FWA-assisted cellular system. The CPE includes a processor and a beam squint compensation controller communicatively coupled to the processor. The beam squint compensation controller receives RF signals from a plurality of UE in the FWA-assisted cellular system. Further, the beam squint compensation controller determines a compensation vector over different frequency sub-bands associated with the at least one UE over which the CPE is preparing the RF signals to be transmitted. Further, the beam squint compensation controller steers a beam of the CPE in a direction towards a network apparatus by performing a beam squint compensation in an uplink based on the compensation vector on the different frequency sub-bands. Further, the beam squint compensation controller transmits the RF signals received from the plurality of UEs to the network apparatus over the different frequency sub-bands.

[0024] The aspects of these embodiments will be better understood with the following description and accompanying drawings. The descriptions illustrate preferred embodiments and specific details but are not limiting. Many modifications can be made within the scope of these embodiments.

[0025] The present disclosure provides an efficient method for fixed wireless access-assisted beam squint compensation in cellular systems.

[0026] These and other features, aspects, and advantages of the present embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0027] Fig. 1 is a schematic diagram that illustrates mmWave propagation according to prior art.

[0028] Fig. 2 is a schematic diagram that illustrates RF distribution in a phased antenna array according to prior art.

[0029] Fig. 3a is a graphical representation of beam squinting with respect to azimuth angle according to prior art.

[0030] Fig. 3b is a graphical representation of beam squinting with respect to signal bandwidth according to prior art.

[0031] Fig. 3c is a graphical representation of beam squinting with respect to Nt according to prior art.

[0032] Fig. 4 is a block diagram that illustrates an FWA assisted cellular system according to embodiments disclosed herein.

[0033] Fig. 5 is a block diagram of a CPE for compensating beam squint in an FWA assisted cellular system according to embodiments disclosed herein.

[0034] Fig. 6 is a flow diagram that illustrates a method of compensating beam squint in an FWA assisted cellular system according to embodiments disclosed herein.

[0035] Fig. 7 is a schematic diagram that illustrates an example scenario of compensating beam squinting in an FWA assisted cellular system according to embodiments disclosed herein.

[0036] Fig. 8 is a schematic diagram that illustrates an antenna array at CPE according to embodiments disclosed herein.

[0037] Fig. 9 is a sequence diagram that illustrates a procedure for compensating beam squint in an FWA assisted cellular system according to embodiments disclosed herein.

[0038] Fig. 10 is a sequence diagram that illustrates a procedure for compensating beam squint with multiple antenna arrays at CPE according to embodiments disclosed herein.

[0039] Fig. 11 is a sequence diagram that illustrates a procedure for compensating beam squint with a single antenna array at CPE according to embodiments disclosed herein.

[0040] Fig. 12 is a graphical representation of beam squint compensation in the uplink according to embodiments disclosed herein.

[0041] It may be noted that, to the extent possible, like reference numerals have been used to represent like elements in the drawing. Furthermore, those of ordinary skill in the art will appreciate that elements in the drawing are illustrated for simplicity and may not necessarily have been drawn to scale. For example, the dimensions of some of the elements in the drawing may be exaggerated relative to other elements to improve the understanding of aspects of the invention. Further, the elements may have been represented in the drawing by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawing with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0042] As is traditional in the field, embodiments are described and illustrated in terms of blocks that carry out a described function or functions. These blocks, which are referred to herein as managers, units, modules, hardware components, or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, and the like, and may optionally be driven by firmware and software. The circuits, for example, may be embodied in one or more semiconductor chips or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware or by a processor (e.g., one or more programmed microprocessors and associated circuitry) or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the proposed method. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the proposed method.

[0043] Referring now to the drawings, and more particularly to Fig. 1 through Fig. 12 where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[0044] Fig. 1 is a schematic diagram that illustrates mmWave propagation according to prior art. Consider a network apparatus (101) equipped with multiple antennas. The multiple antennas associated with the network apparatus (101) propagate beams (103) at frequencies between 24GHz-100GHz for 5G and beyond. The beams are propagated to devices (105, 109) and users (107, 111). The multiple antennas perform phase shifting and amplitude scaling for the radio signals transmitted or for the radio signals received. The phase shifting and amplitude scaling performed at the antenna are referred to as beamforming. The beams propagated experience different propagation characteristics such as high free space path loss, penetration loss, high diffraction loss, atmospheric loss, and the like. The penetration loss occurs while penetrating through materials such as glass, buildings, and the like.

[0045] Fig. 2 is a schematic diagram that illustrates RF distribution in a phased antenna array according to prior art. In a phased antenna array, the antennas (2011, 2012, 2013, 201N) are placed in an array fashion next to each other. Further, for each beam (2031, 2032, 2033, 203N) in the phased antenna array, the phase (Φ1, Φ2, Φ3, ΦN) of an original RF signal is shifted by fractions of a wavelength for each individual antenna (2011, 2012, 2013, 201N). Further, a boresight direction (θ=0) is defined perpendicular to the face of the antenna. A positive angle θ is defined to the right of boresight and a negative angle is defined to the left of boresight.

[0046] Further, in a wideband system the signal arrives at different times at the different antenna elements in a phased antenna array. Thus, the delay depends on spacing between the antennas (2011, 2012, 2013, 201N) and angle of incidence. The delay is determined as shown in below equation 1:

[0047] ---1

[0048] Phase shifters are relatively good approximations to the ideal time shifters for narrowband transmission; however, this approximation does not hold for wideband transmission because the required phase shifts are frequency-dependent. Hence, as a result, the beams for frequencies other than the carrier deviate as a function of frequency in wideband systems, which is referred to as beam squint.

[0049] Fig. 3a is a graphical representation of beam squinting with respect to azimuth angle, according to prior art. The graphical representation is considered for parameters: carrier frequency being 28GHz (fc = 28 GHz), bandwidth being 1GHz (BW=1GHz), Nt being 256, and θ (Angle of Deviation) being 50°, where Nt is the number of antennas. The beam deviation angle is approximately 0.9 degrees for 1 GHz of the bandwidth at 28 GHz carrier frequency. Even a relatively narrow bandwidth can result in significant beam squinting at high frequencies, which poses a challenge for designing high-frequency communication systems. When the beam deviates from its intended direction, it can lead to poorer signal quality and interfere with nearby channels, ultimately impacting the system's overall performance.

[0050] Fig. 3b is a graphical representation of beam squinting with respect to signal bandwidth, according to prior art. The gain of the antenna array decreases with an increase in the signal bandwidth due to beam squint. As the bandwidth grows, the signal’s frequency components further spreads out. This causes the beam to shift even more from its intended direction and reduces a gain of the antenna array, as the energy becomes less concentrated in the required direction. This issue is challenges in wideband communication systems, where high gain and precise beam alignment ensures high data rates and communication links.

[0051] Fig. 3c is graphical representation of beam squinting with respect to Nt, according to prior art. The beam squint effect becomes more prominent as the antenna array size increases because of the total delay. The transmitting signal bandwidth (corresponding to 3dB) could be determined with respect to the antenna array size. When antenna arrays get larger, the beam squint effect becomes more of a problem because of the delays introduced between the elements. These delays occur as signal components take slightly different paths through the array, leading to greater variation. The bigger the array, the more noticeable the beam shift becomes, making it increasingly difficult to keep the beam properly aligned across a wide range of frequencies. This makes it essential to design antenna arrays and develop smart signal processing techniques to reduce beam squint and maintain performance in cutting-edge communication systems.

[0052] Fig. 4 is a block diagram that illustrates the FWA assisted cellular system, according to embodiments disclosed herein. The FWA assisted cellular system includes a network apparatus (401), a CPE (403) and plurality of UEs (4051, 4052) that communicates with each other for compensating beam squint.

[0053] The network apparatus (401) includes various hardware and software components that facilitate communication between user equipment and network infrastructure. Examples of the network apparatus (501) can include, but is not limited to Base Stations (such as macro cells, small cells, femtocells, picocells) for wireless communication, Antennas and RF Units (e.g., MIMO, beamforming) to enhance signal coverage and data throughput, Core Network Equipment (e.g., MMEs, S-GWs, P-GWs in 4G; AMFs, UPFs in 5G) for data routing, mobility, and session control, Network Function Virtualization (NFV) and Software-Defined Networking (SDN) for dynamic resource allocation and scalability, Edge Computing Nodes (e.g., MEC servers) for low-latency processing, Backhaul and Transport Equipment (e.g., fiber-optic links, microwave relays, Ethernet switches) to connect base stations to the core network, Network Management Systems (NMS) and Operation Support Systems (OSS) for network configuration, fault management, and optimization, Radio Network Controllers (RNCs) in 3G, Distributed Units (DUs), and Centralized Units (CUs) in 5G, Network Slicing Components for virtualized resource allocation, Security elements (e.g., Firewalls, IDS, AAA Servers) for secure communication.

[0054] Examples of the wireless communication network system include, but are not limited to, Cellular Networks (such as 2G, 3G, 4G, 5G, Beyond 5G (B5G) / 6G, or advanced cellular networks), Local Area Networks (LANs) (such as Wi-Fi, Li-Fi, etc.), Personal Area Networks (PANs) (such as Bluetooth, Zigbee, Z-Wave, etc.), Wide Area Networks (WANs) (such as Satellite Communication Networks, Long Range Wide Area Network, Narrowband IoT, Low-bandwidth communication for IoT, etc.), Metropolitan Area Networks (MANs), Machine-to-Machine (M2M), Ad Hoc and Mesh Networks, Emerging and Advanced Networks.

[0055] Examples of the UE can include, but are not limited to, Consumer Electronics (such as Mobile Phones and Smartphones), Tablets, Wearable Devices, Computing Devices (such as Laptops, Notebooks, Desktops, Workstations, etc.), IoT Devices, Automotive Systems (such as connected cars, Autonomous Vehicles, Vehicle-to-Everything (V2X) communication devices, etc.), Enterprise Devices such as robotics, Specialized Equipment (such as Medical Devices, Public Safety Devices, etc.), Media Devices (such as Gaming Consoles, Streaming Devices, etc.).

[0056] The CPE (403) cane be installed at a user’s location, such as a home, office, or business. The CPE (403) is used to provide access to telecommunication services like internet, voice, and video. Examples of the CPE (403) include, but is not limited to, modems, routers, home gateways, and set-top boxes.

[0057] The network apparatus (401) transmits or receives the mmWaves to / from plurality of UEs (4051, 4052) through CPE (403). Similarly, the plurality of UEs (4051, 4052) can transmit or receive the mmWaves to / from the network apparatus (401) through the CPE (403). During the transmission or reception between the network apparatus (401) and the plurality of UEs (4051, 4052) the CPE (403) mitigates the beam squinting in the mmWave and steers the beam in the desired direction from the CPE (403) to the network apparatus (401). In an embodiment, the network apparatus (401) can mitigate or compensate the beam squinting of the received mmWaves.

[0058] Fig. 5 is the block diagram of the CPE for compensating beam squint in FWA assisted cellular system, according to embodiments disclosed herein. The CPE (403) is the device that is located at the customer premises such as home, office or business and the like. For example, the CPE (403) can be, but is not limited to, a modems, routers, and home gateways, set-up boxes. The CPE (403) includes a processor (407), a memory (409), an I / O interface (411), and a beam squint compensation controller (413). Furthermore, the processor (407) of the CPE (403) communicates with the memory (409), the I / O interface (411), and the beam squint compensation controller (413). The processor (407) is configured to execute instructions stored in the memory (409) and to perform various processes. The processor (407) can include one or a plurality of processors, can be a general-purpose processor such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an Artificial Intelligence (AI) dedicated processor such as a neural processing unit (NPU).

[0059] Furthermore, the memory (409) of the CPE (403) includes storage locations that can be addressed through the processor (407). The memory (409) is not limited to volatile or non-volatile memory and can include one or more computer-readable storage media. Non-volatile storage elements such as magnetic hard disks, optical discs, floppy discs, flash memories, EPROM, or EEPROM memories can also be included in the memory (409). Further, the memory (409) of the CPE (403) can store various information received from UEs (405) and network apparatus (401). The CPE (403) can store several pieces of information such as beam forming vector, carrier frequency, deviated frequency, compensation vector, distance between antenna elements.

[0060] The I / O interface (411) transmits information between the memory (409) and external peripheral devices, which are input-output devices associated with the CPE (403). The I / O interface (411) receives various information from the UE (4051, 4052) and the network apparatus (401). This interface is used to maintain seamless communication between the CPE (403) and external devices, ensuring that data is transmitted and received. Additionally, the I / O interface (411) facilitates the integration of the CPE (403) with other network components, enhancing its capability for compensating beam squint in FWA assisted cellular system.

[0061] The beam squint compensation controller (413) communicates with the I / O interface (411) and the memory (409) for compensating beam squint in FWA assisted cellular system. The beam squint compensation controller (413) is an innovative hardware that is implemented in the CPE (403). In an embodiment, the structure of such innovative integrated circuit includes a multi-core architecture that that enables beam squint compensation in FWA assisted cellular system. Each core is optimized for specific tasks such as beam squint detection, calculation, and compensation. The innovative integrated circuit for beam squint compensation in FWA assisted cellular system is made up of a combination of analog and digital components designed to mitigate the beam squinting in the millimeter-wave (mmWave) system and steers the beam in the desired direction from the CPE (403) to the network apparatus in the uplink. The analog components include a low-noise amplifier and a high-precision analog-to-digital converter to ensure accurate signal processing. The digital components consist of a microcontroller unit (MCU) and a digital signal processor (DSP) that work in tandem to perform the beam squint compensation.

[0062] The beam squint compensation controller (413) receives the RF signals from the plurality of UEs (4051, 4052) in the FWA-assisted cellular system. Further, the beam squint compensation controller (413) determines a compensation vector over different frequency sub-bands associated with the at least one UE (4051, 4052) over which the CPE is preparing the RF signals to be transmitted. Further, the beam squint compensation controller (413) steers the beam of the CPE (403) in the direction towards the network apparatus (401) by performing the beam squint compensation in an uplink based on the compensation vector on the different frequency sub-bands. Further, the beam squint compensation controller (413) transmits the RF signals received from the plurality of UEs (4051, 4052) to the network apparatus (401) over the different frequency sub-bands. The CPE (403) includes the single antenna array or multiple antenna arrays that are placed at the predefined distance. Also, the single antenna array or multiple antenna arrays can be uniform linear antenna arrays or uniform planar arrays.

[0063] In an embodiment, the steering of the beam in the direction towards the network apparatus is performed by determining the first beam forming vector (w1) at a first reference frequency (f1) for the RF signals based on the carrier frequency (fc), speed of light, distance between two antenna elements placed at CPE, and the beamforming direction. Further, the beam squint compensation controller (413) determines the deviated frequency (delta f) at which the RF signals are received over the least one frequency sub-band based on the carrier frequency. Further, the beam squint compensation controller (413) determines the compensation vector based on the deviated frequency, speed of light, distance between two antenna elements placed at CPE (403), and the desired beamforming direction. Further, the beam squint compensation controller (413) determines the second beam forming vector (w2) at a second frequency (f2) at which the RF signals are to be transmitted to the network apparatus (401) based on the first beam forming vector and the compensation vector. Further, the beam squint compensation controller (413) steers the beam in the direction towards the network apparatus (401) based on the second beam forming vector.

[0064] In an embodiment, the beam squint compensation controller (413) steers the beam of the CPE (403) in the direction towards the network apparatus (401) by performing the beam squint compensation simultaneously using the multiple antenna arrays based on different compensation vectors on the at least one frequency sub-band. Further, the beam squint compensation controller (413) transmits the compensated RF signals simultaneously from multiple antenna arrays to the network apparatus (401).

[0065] In an embodiment, the beam squint compensation controller (413) steers the beam of the CPE (403) in the direction towards the network apparatus (401) by performing the beam squint compensation sequentially at the different time slots based on different compensation vectors on at least one frequency sub-band. Further, the beam squint compensation controller (413) transmits the compensated RF signals sequentially at different time slots from single antenna arrays to the network apparatus.

[0066] In an embodiment, the frequency sub-band is associated with a beam squint indicator (BSI) that corresponds to a sound reference signal (SRS). The BSI is used to identify which frequency range needs adjustment. By linking the BSI to a specific frequency range, the system can precisely target it for correction. This ensures that signals are transmitted, without unnecessary distortion.

[0067] In an embodiment, the beam squint compensation controller (413) receives the request message from the network apparatus (401) for compensating RF signals received over the at least one frequency sub-band associated with a BSI. The request message comprises the BSI at which the RF signals are to be compensated. This request message is used as a trigger for the beam squint compensation controller (413) to start the compensation process. Once the request is received, the beam squint compensation controller (413) evaluates the BSI and determines how to adjust the signal for the specific frequency range. This ensures that signals are fine-tuned in real time, preserving the strength and quality of the connection between user devices and the network equipment. The beam squint compensation controller (413) optimizes the transmission of signals in systems that rely on fixed wireless access. By calculating the necessary adjustments and directing the beam toward the network equipment, the controller ensures a stable and connection.

[0068] The proposed CPE (403) offers a straightforward beam squint detection calculation and compensation method for FWA-assisted cellular systems. The compensation vector is generated based on the beamforming vector. The compensation is achieved through a simple matrix multiplication. The compensation vector is multiplied with the beam squinted beamforming vector to perform the compensation. Additionally, a new parameter, BSI (beam squint indicator), is introduced, corresponding to the SRS of a beam at the CPE (403).

[0069] Fig. 6 is a flow diagram that illustrates a method for compensating beam squint in an FWA-assisted cellular system according to embodiments disclosed herein.

[0070] At block 601, the method includes receiving the RF signals from the multiple of UEs (4051, 4052) in the FWA-assisted cellular system. The signals from UEs (4051, 4052) form the starting point for processing and adjustment. These signals are usually received by the equipment at the customer’s location, such as a modem or router, but they often encounter distortions and interference along the way. To ensure a stable connection, these issues must be corrected.

[0071] At block 603, the method includes determining the compensation vector over different frequency sub-bands associated with the UEs (4051, 4052) over which the CPE (403) is preparing the RF signals to be transmitted. The compensation vector serves as a key measurement, indicating the precise adjustments needed to align the beam correctly. Advanced algorithms handle this process, considering how beam misalignment varies with frequency and adapting to the ever-changing conditions of the wireless environment.

[0072] At block 605, the method includes steering the beam of the CPE (403) in the direction towards the network apparatus (401) by performing the beam squint compensation in an uplink based on the compensation vector on the different frequency sub-bands. By using the compensation vector, the CPE (403) can fine-tune the phase and amplitude of signals across different frequency ranges. This adjustment ensures the beam is directed toward the network equipment, reducing signal loss and improving the overall connection quality.

[0073] At block 607, the method includes transmitting the RF signals received from the UEs (4051, 4052) to the network apparatus (401) over the different frequency sub-bands.

[0074] Fig. 7 is the schematic diagram that illustrates the example scenario of compensating the beam squinting in FWA assisted cellular system, according to embodiments disclosed herein. Consider a scenario where the CPE (403) receives the RF signals from the plurality of UEs (4051, 4052). The RF signals (8011, 8012, 8013, 8014, 8015, 8016, 8017) from the plurality of UEs (4051, 4052) are received by plurality of antennas (8031, 8032, 8033, 803n) that arranged in an uniform manner on the CPE (403) as shown in Fig. 8. Also, the RF signals are received at different angles θi at each antenna. Also, the antenna arrays are placed at a distance d. the distance d=λ / 2. Further, the array response vector is determined using the below equation 2:

[0075] ----2

[0076] In the above equation 2, The θi is the azimuth angle ∈ (-90,90), fc is the carrier frequency, c is the speed of the light, and d is the spacing between two antenna elements.

[0077] Further, the beamforming vector (w1) is defined as in below equation 3:

[0078] ---3

[0079] In the above equation 3, θi is the desired beamforming direction.

[0080] Upon determining the beam forming vector, a first beam gain g1 for frequency fc is given as in below equation 4:

[0081] ---4

[0082] Similarly, consider the same beamforming vector w is used to beamform the array response that is operating at a frequency f2, where f2 is a sum of carrier frequency and delta f (Δf). Further, a second beam gain g2 is determined using the frequency f2 as shown in below equation 5:

[0083]

[0084] Where, ---6

[0085] Also, a filter is applied at a frequency f2 in order to compensate for the phase deviation δ.

[0086] Further, the first beam gain g1(w,θ) and the second beam gain g2(w,θ) are compared to determine the deviation δ for each antenna element. In order to compensate for the deviation, a vector w2 is used at the frequency f2 as shown in below equation 7:

[0087] ---7

[0088] Where ⊙ is the Hadamard product and C is the compensation vector to cancel the effect of the deviation and is defined as shown in below equation 8:

[0089]

[0090] Also, the compensation vector is determined using the below equation 9:

[0091] , where and is the antenna index in row and the column of the UPA.

[0092] Fig. 9 is the sequence diagram that illustrates the procedure for compensating beam squint in FWA assisted cellular system, according to embodiments disclosed herein. At step S1, the network apparatus (401) sends a control information on a control channel to the CPE (403) . The control information can include, but is not limited to, beam information and timing information, system information such as Master Information Block (MIBs), System Information Block (SIBs), a Down Link Control Information (DCI), RRC signaling, Beam management and CSI feedback, paging information and control commands. This control information is used by the CPE (403) to synchronize and align with the network apparatus (401).

[0093] At step S2, the CPE (403) acknowledges the transmission request received from the network apparatus (401) on the control channel. At step S3, the network apparatus (401) transmits the RF signals over different frequency sub-bands on the traffic channel to the CPE (403). At step S4, in response to receiving the RF signals, the CPE (403) transmits the RF signals to the UE (405) over the Wi-Fi link (downlink). Further, at step S5, the RF signals are received by the CPE (403) from the UE (405) over the Wi-Fi in the uplink. At step S6, the CPE (403) performs the beam link compensation in the uplink using the compensation vector on the various frequency sub-bands. At step S7, upon beam link compensation, the CPE (403) transmits the compensated RF signals to the network apparatus (401) on different frequency sub-bands.

[0094] Fig. 10 is a sequence diagram that illustrates a procedure for compensating beam squint with multiple antenna arrays at CPE according to embodiments disclosed herein. At step S1, the network apparatus (401) sends control information on a control channel to the CPE (403). The control information can include, but is not limited to, the beam information and the timing information.

[0095] Further, at step S2, the CPE (403) acknowledges the transmission request received from the network apparatus (401) on the control channel. At step S3, the network apparatus (401) transmits the RF signals over different frequency sub-bands on the traffic channel to the CPE (403). At step S4, in response to receiving the RF signals, the CPE (403) transmits the RF signals to the UE (405) over the Wi-Fi link (downlink). Furthermore, at step S5, the RF signals are received by the CPE (403) from the UE (405) over the Wi-Fi in the uplink. At step S6, the multiple antenna arrays at the CPE (403) facilitate simultaneous beamforming for various sub-band transmissions. Also, the beam squint compensation in the uplink is performed at the CPE (403) simultaneously with the help of multiple antenna arrays using the distinct compensation vectors on the frequency bands. At step S7, the CPE (403) simultaneously transmits the compensated RF signals on different sub-bands to the network apparatus (401) in the uplink.

[0096] Fig. 11 is a sequence diagram that illustrates a procedure for compensating beam squint with a single antenna array at CPE according to embodiments disclosed herein. At step S1, the network apparatus (401) sends control information on a control channel to the CPE (403). The control information can include, but is not limited to, the beam information and the timing information.

[0097] Further, at step S2, the CPE (403) acknowledges the transmission request received from the network apparatus (401) on the control channel. At step S3, the network apparatus (401) transmits the RF signals over different frequency sub-bands on the traffic channel to the CPE (403). At step S4, in response to receiving the RF signals, the CPE (403) transmits the RF signals to the UE (405) over the Wi-Fi link (downlink).

[0098] Furthermore, at step S5, the RF signals are received by the CPE (403) from the UE (405) over the Wi-Fi in the uplink. At step S6, since there isonlyone antenna array at the CPE (403), the beamforming for different sub-bands is performed in different time slots (sequentially). Also, the beam squint compensation in the uplink is performed one by one at the CPE with the help of a single antenna array using the distinct compensation vectors on the frequency bands. At step S7, the CPE (403) transmits the compensated RF signals one by one on different sub-bands in the uplink in different time slots to the network apparatus (401).

[0099] Fig. 12 illustrates the beam squint compensation in the uplink using the proposed solution. The various simulation parameters that is considered during simulation are fc = 28 GHz, Δf = ±1 GHz, Nt = 256, and AoD = 40o. In an embodiment, if compensation is not required over the whole band, sub-band level compensation is also possible. During the sub-band level compensation, the CPE (403) will divide the wideband into number of sub-bands and assign an index to each band. The index can be called as Beam Squint Indicator (BSI). Each BSI corresponds to a Sounding Reference Signal (SRS) of the beam at CPE (403). Further, the network apparatus (403) has the information of BSIs corresponding to the sub-bands and beams. The network apparatus (401) receives the SRS from the beams at CPE (403) and evaluate the quality of SRS of multiple beams from CPE (403). Further, when the quality of the beamformed SRS degrades, the network apparatus (401) will send the BSI to the CPE (403) to compensate its beam at sub-band level.

[0100] The proposed solution can be utilized in various applications, including rural broadband coverage, temporary event network support, mobile office solutions, industrial automation, IoT applications, network transformation of schools and educational institutions, and smart city projects. A beam squint detection, calculation, and compensation solution is proposed as described above. The proposed solution involves a CPE beamformer in the FWA network, which mitigates beam squinting in the millimeter-wave (mmWave) system and steers the beam in the desired direction from the CPE to the network apparatus in the uplink. Additionally, a new parameter, the BSI, corresponding to the Sounding Reference Signal (SRS) of the beam at the CPE, is introduced. The proposed method can be an essential feature for FWA and may be incorporated into future standards for XL-MIMO and high-frequency communications.

[0101] The foregoing description of the specific embodiments will fully reveal the general nature of the embodiments herein such that others can readily modify and / or adapt such specific embodiments for various applications without departing from the generic concept. Therefore, such adaptations and modifications are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Thus, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the scope of the embodiments as described herein.

Claims

1.A method for compensating beam squint in a Fixed Wireless Access (FWA)-assisted Cellular system, comprising:receiving, by a Customer Premises Equipment (CPE) (403), Radio Frequency (RF) signals from at least one User Equipment (UE) (405) in the FWA-assisted cellular system;determining, by the CPE (403), a compensation vector over different frequency sub-bands associated with the at least one UE (405) over which the CPE (403) is preparing the RF signals to be transmitted;steering, by the CPE (403), a beam of the CPE (403) in a direction towards a network apparatus (401) by performing a beam squint compensation in an uplink based on the compensation vector on the different frequency sub-bands; andtransmitting, by the CPE (403), the RF signals received from the at least one UE (405) to the network apparatus (401) over the different frequency sub-bands.2.The method as claimed in claim 1, wherein the CPE (403) comprises at least one of a single antenna array or multiple antenna arrays that is placed at a predefined distance, and wherein the at least one of the single antenna array or multiple antenna arrays is at least one of a uniform linear antenna arrays or uniform planner arrays.3.The method as claimed in claim 1, wherein steering the beam in the direction towards network apparatus (401) by performing beam squint compensation in an uplink based on a compensation vector on different frequency sub-band comprises:determining, by the CPE (403), a first beam forming vector (w1) at a first reference frequency (f1) for the RF signals based on a carrier frequency (fc), speed of light, distance between two antenna elements placed at CPE (403) and a desired direction beamforming direction;determining, by the CPE (403), a deviated frequency (delta f) at which the RF signals are received over least one frequency sub-band based on the carrier frequency;determining, by the CPE (403), a compensation vector based on the deviated frequency, speed of light, distance between two antenna elements placed at CPE (403) and a desired direction beamforming direction;determining, by the CPE (403), a second beam forming vector (w2) at a second frequency (f2) at which the RF signals are to be transmitted to the network apparatus (401) based on the first beam forming vector and the compensation vector; andsteering, by the CPE (403), the beam in the direction towards network apparatus (401) based on the second beam forming vector.4.The method as claimed in claim 1 comprises:steering, by the CPE (403), a beam of the CPE (403) in a direction towards the network apparatus (401) by performing the beam squint compensation simultaneously using the multiple antenna arrays based on different compensation vector on at least one frequency sub-band; andtransmitting, by the CPE (403), compensated RF signals simultaneously from multiple antenna arrays to the network apparatus (401).5.The method as claimed in claim 1 comprises:steering, by the CPE (403), a beam of the CPE (403) in a direction towards a network apparatus (401) by performing the beam squint compensation sequentially at the different time slots based on different compensation vector on at least one frequency sub-band; andtransmitting, by the CPE (403), compensated RF signals sequentially at different time slots from single antenna arrays to the network apparatus (401).6.The method as claimed in claim 1, wherein at least one frequency sub-band is associated with a bean squint indicator (BSI) that corresponds to a sound reference signal (SRS).7.The method as claimed in claim 6, comprises:receiving, by the CPE (403), a request message from the network apparatus (401) for compensating RF signals received over the at least one frequency sub-band associated with a BSI, wherein the request message comprises the BSI at which the RF signals are to be compensated.8.A CPE (403) for compensating beam squint in a Fixed Wireless Access (FWA)-assisted Cellular system, comprises:a processor (407); anda beam squint compensation controller (413) communicatively coupled with the processor (407), wherein the beam squint compensation controller (413):receives Radio Frequency (RF) signals from a plurality of User Equipment (UE) (405) in the FWA-assisted cellular system;determine a compensation vector over different frequency sub-bands associated with the at least one UE (405) over which the CPE (403) is preparing the RF signals to be transmitted;steers a beam of the CPE (403) in a direction towards a network apparatus (401) by performing a beam squint compensation in an uplink based on the compensation vector on the different frequency sub-bands; andtransmit the RF signals received from the plurality of UEs (405) to the network apparatus (401) over the different frequency sub-bands.

Images