Patent Application
20240313398
This disclosure relates generally to antenna arrays in wireless communications systems. Embodiments of this disclosure relate to methods and apparatuses for scalably arranging antenna elements of a 2D antenna array in groups with a shared time delay to facilitate combining vertical beam steering and horizontal beam spreading to generate a frequency dependent beam spread.
To meet the demand for wireless data traffic having increased since deployment of 4G communication systems and to enable various vertical applications, 5G/NR communication systems have been developed and are currently being deployed. The 5G/NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60 GHz bands, so as to accomplish higher data rates or in lower frequency bands, such as 6 GHZ, to enable robust coverage and mobility support. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beam forming, and large scale antenna techniques are discussed in 5G/NR communication systems.
In addition, in 5G/NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-point (COMP), reception-end interference cancelation and the like.
Analog beamforming systems have been widely used in wireless communication systems to overcome excessive path loss. The challenge for an analog beamforming system is that beamforming is achieved in the time domain. Therefore, typically only one beam can be formed at a time. This limits the beam pairing and beam tracking capability when multiple users are in the cell to be connected to the base station at the same time, due to the beam switching overhead. It is also challenging for the uplink in the Time Division Duplex (TDD) system because the user only gets allocated in a short period of time to transmit. There is a need for a multi-beam system that supports multiple simultaneous radio frequency (RF) beams without sacrificing the antenna array gain.
Embodiments of the present disclosure provide methods and apparatuses that facilitate the design of scalable two-dimensional (2D) joint phase-time arrays (JPTA) that support multiple simultaneous RF beams without sacrificing the antenna array gain.
In one embodiment, a 2D antenna array is provided, comprising a first number (M) of antenna groups that each comprise a second number (N) of antenna elements and N phase shifters, each antenna element operably coupled to a corresponding one of the phase shifters. The 2D antenna array further comprises M delay elements, each delay element operably coupled to a corresponding one of the antenna groups and configured to apply a respective time delay to a first signal to be transmitted by the corresponding antenna group, wherein each phase shifter in the corresponding antenna group is configured to apply a respective phase shift to the time-delayed first signal and feed the phase-shifted-and-time-delayed first signal to the corresponding antenna element. Each delay element is further configured to apply the respective time delay to a second signal that is received from the corresponding antenna group, wherein each phase shifter in the corresponding antenna group is configured to apply the respective phase shift to a third signal received from the corresponding antenna element, and wherein the second signal is a combination of the phase-shifted third signals. The antenna groups are further configured to form multiple beams based on the phase shifts and the time delays. The time delays are configured to produce a beam spread in a first dimension of the 2D antenna array such that the multiple beams are formed in different directions.
In another embodiment, a method of operation of a 2D antenna array comprising a first number (M) of antenna groups that each comprise a second number (N) of antenna elements and N phase shifters, each antenna element operably coupled to a corresponding one of the phase shifters, and M delay elements each operably coupled to a corresponding one of the antenna groups, is provided. The method comprises the steps of applying, by each of the delay elements, a respective time delay to a first signal to be transmitted by the corresponding antenna group and applying, by each phase shifter in the corresponding antenna group, a respective phase shift to the time-delayed first signal and feeding the phase-shifted-and-time-delayed first signal to the corresponding antenna element, or applying, by each of the delay elements, the respective time delay to a second signal that is received from the corresponding antenna group and applying, by each phase shifter in the corresponding antenna group, the respective phase shift to a third signal received from the corresponding antenna element, wherein the second signal is a combination of the phase-shifted third signals. The method further comprises forming multiple beams based on the phase shifts and the time delays. The time delays are configured to produce a beam spread in a first dimension of the 2D antenna array such that the multiple beams are formed in different directions.
In another embodiment, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium is configured to store instructions that, when executed by a processor, cause a 2D antenna array comprising a first number (M) of antenna groups that each comprise a second number (N) of antenna elements and N phase shifters, each antenna element operably coupled to a corresponding one of the phase shifters, and M delay elements each operably coupled to a corresponding one of the antenna groups, to apply, via each of the delay elements, a respective time delay to a first signal to be transmitted by the corresponding antenna group and apply, via each phase shifter in the corresponding antenna group, a respective phase shift to the time-delayed first signal and feed the phase-shifted-and-time-delayed first signal to the corresponding antenna element. The instructions, when executed, further cause the 2D antenna array to apply, via each of the delay elements, the respective time delay to a second signal that is received from the corresponding antenna group and apply, via each phase shifter in the corresponding antenna group, the respective phase shift to a third signal received from the corresponding antenna element, wherein the second signal is a combination of the phase-shifted third signals. The instructions, when executed, further cause the 2D antenna array to form multiple beams based on the phase shifts and the time delays. The time delays are configured to produce a beam spread in a first dimension of the 2D antenna array such that the multiple beams are formed in different directions.
Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.
Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term “controller” means any device, system or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and/or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another and does not limit the components in other aspect (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element.
As used herein, the term “module” may include a unit implemented in hardware, software, or firmware, and may interchangeably be used with other terms, for example, “logic,” “logic block,” “part,” or “circuitry”. A module may be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, according to an embodiment, the module may be implemented in a form of an application-specific integrated circuit (ASIC).
Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.
Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.
The discussion of 5G systems and frequency bands associated therewith is for reference as certain embodiments of the present disclosure may be implemented in 5G systems. However, the present disclosure is not limited to 5G systems or the frequency bands associated therewith, and embodiments of the present disclosure may be utilized in connection with any frequency band. For example, aspects of the present disclosure may also be applied to deployment of 5G communication systems, 6G or even later releases which may use terahertz (THz) bands.
For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
Embodiments of the present disclosure recognize that a joint phase-and-timed array (JPTA) architecture can allow multiple UEs to be connected to a base station simultaneously, reducing the need for time multiplexing which allows the base station to allocate more time for individual UEs, increasing the SNR at the receiver side. This allows support for longer range, higher data rate, or reduced UE transmit power requirements to reduce the power consumption of the UE.
However, embodiments of the present disclosure further recognize that implementations of the JPTA architecture that require one delay element for each antenna element can increase system complexity, cost, and power consumption of the base station significantly. Additionally, adding these delay elements to a 2D array could violate spacing constraints in mmWave systems, preventing the JPTA architecture from being scalable to a 2D array.
Accordingly, embodiments of the present disclosure arrange multiple antenna elements in groups that share one delay element. Each antenna element is connected to its own RF front end circuits, and the shared one delay element is configured for a beam spread to support multiple beams in different directions. Such architectures allow combining vertical beaming steering and horizontal beam spreading to generate a frequency dependent beam spread.
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The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business; a UE 112, which may be located in an enterprise; a UE 113, which may be a WiFi hotspot; a UE 114, which may be located in a first residence; a UE 115, which may be located in a second residence; and a UE 116, which may be a mobile device, such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G/NR, long term evolution (LTE), long term evolution-advanced (LTE-A), WiMAX, WiFi, or other wireless communication techniques.
Depending on the network type, the term “base station” or “BS” can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G/NR base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 5G/NR 3rd generation partnership project (3GPP) NR, long term evolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience, the terms “BS” and “TRP” are used interchangeably in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, the term “user equipment” or “UE” can refer to any component such as “mobile station,” “subscriber station,” “remote terminal,” “wireless terminal,” “receive point,” or “user device.” For the sake of convenience, the terms “user equipment” and “UE” are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).
Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.
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The transceivers 210a-210n receive, from the antennas 205a-205n, incoming RF signals, such as signals transmitted by UEs in the network 100. The transceivers 210a-210n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are processed by receive (RX) processing circuitry in the transceivers 210a-210n and/or controller/processor 225, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The controller/processor 225 may further process the baseband signals.
Transmit (TX) processing circuitry in the transceivers 210a-210n and/or controller/processor 225 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor 225. The TX processing circuitry encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The transceivers 210a-210n up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205a-205n.
The controller/processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller/processor 225 could control the reception of UL channel signals and the transmission of DL channel signals by the transceivers 210a-210n in accordance with well-known principles. The controller/processor 225 could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor 225 could support beam forming or directional routing operations in which outgoing/incoming signals from/to multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the gNB 102 by the controller/processor 225.
The controller/processor 225 is also capable of executing programs and other processes resident in the memory 230, such as an OS. The controller/processor 225 can move data into or out of the memory 230 as required by an executing process.
The controller/processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G/NR, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or transceiver.
The memory 230 is coupled to the controller/processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.
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The transceiver(s) 310 receives, from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100. The transceiver(s) 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is processed by RX processing circuitry in the transceiver(s) 310 and/or processor 340, which generates a processed baseband signal by filtering, decoding, and/or digitizing the baseband or IF signal. The RX processing circuitry sends the processed baseband signal to the speaker 330 (such as for voice data) or is processed by the processor 340 (such as for web browsing data).
TX processing circuitry in the transceiver(s) 310 and/or processor 340 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The transceiver(s) 310 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) 305.
The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 could control the reception of DL channel signals and the transmission of UL channel signals by the transceiver(s) 310 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.
The processor 340 is also capable of executing other processes and programs resident in the memory 360. The processor 340 can move data into or out of the memory 360 as required by an executing process. In some embodiments, the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is also coupled to the I/O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I/O interface 345 is the communication path between these accessories and the processor 340.
The processor 340 is also coupled to the input 350, which includes for example, a touchscreen, keypad, etc., and the display 355. The operator of the UE 116 can use the input 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites.
The memory 360 is coupled to the processor 340. Part of the memory 360 could include a random-access memory (RAM), and another part of the memory 360 could include a Flash memory or other read-only memory (ROM).
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In this architecture there are M antenna elements, and the number of phase shifters and number of delay elements are both set to M—that is, there is one phase shifter and one delay element coupled to each antenna. Antenna m is designed to have a delay variation τm,1∈[0, (m−1)sin(Δθmax)/W], where W is the system bandwidth and Δθmax is the maximum desired beam-sway in one direction from the center angle.
In this architecture, for each angle in the vicinity of θ1, there is a unique frequency region where the peak beamforming gain is obtained. Thus, in fast user mobility scenarios, by observing the frequency or sub-carrier where the highest signal power is obtained, the receiver can estimate the best beam direction or the required beam correction to be used at the transmitter. Thus, fast beam-alignment can be achieved using this architecture. Furthermore, as the user moves away by more than a 3 dB beam-width on one frequency, the signal to noise ratio (SNR) does not completely fall to zero on the whole band. Rather, the maximum beamforming gain shifts to a different frequency. This can be beneficial since it can provide a smooth degradation of service with user mobility and does not cause sudden outage as in the case of frequency-flat beamforming.
It is also noted that in the cell edge case, the UE transmitter typically has to boost the transmit output power for the base station (i.e., the gNB) to receive its signal above the sensitivity level. However, the transmit power is bounded by regulatory and absorption rate limitations. Therefore, the UEs could be power limited. JPTA allows multiple UEs to be connected to a base station simultaneously, reducing the need for time multiplexing. This essentially allows the base station to allocate more time for the cell edge UEs through JPTA, resulting in higher SNR at the receiver side that can support longer range, higher data rate, or reduced UE transmit power requirements to reduce the power consumption.
However, such implementations of the JPTA architecture require one delay element for each antenna element (as illustrated in architecture 500). A large number of antennas are deployed in a commercial base station, typically arranged in a 2D antenna array. Such arrays can have dimensions as large as 16×16, for example. In this case, 256 delay elements would be needed. Inclusion of one delay element per antenna in such an array increases the system complexity, cost, and power consumption significantly.
The 2D phased-array system may also require near λ/2 spacing between antenna elements. At mmWave frequencies the wavelength is very short, which limits the dimensions of the transceiver ICs since, on average, each channel may need to be smaller than λ/2×λ/2 in size in order to make the 2D array scalable. Adding extra delay elements could violate such spacing constraints, preventing the JPTA architecture from being scalable to a 2D array.
Various embodiments of the present disclosure provide a JPTA architecture that organizes the antenna elements in groups, so that multiple antennas can share one delay element. Each antenna element is connected to its own RF front end circuits, such as a power amplifier (PA), low-noise amplifier (LNA), and phase shifter (PS) for the RF signal amplification and phased-array operation. There are multiple methods to group the antennas, where each group can be arranged in multiple different horizontal and vertical dimensions, based on the system performance and integrated circuit partitioning.
For a transmit beamforming operation, at step 1405 each of the delay elements applies a respective time delay to a first signal to be transmitted by the antenna group corresponding to that delay element. The first signal is generated by a modem and converted to an analog signal by a DAC before being provided to the delay elements.
Next, each phase shifter in the antenna group applies a respective phase shift to the time-delayed first signal and feeds the phase-shifted-and-time-delayed first signal to the antenna element corresponding to that phase shifter (step 1410).
At step 1415, the antenna groups form multiple beams based on the phase shifts and the time delays. In this case, the beams are transmit beams, and are used to transmit the first signal. The time delays are configured to produce a beam spread in a first dimension of the 2D antenna array such that the multiple transmit beams are formed in different directions. This allows for a combination of vertical beaming steering and horizontal beam spreading to generate a frequency dependent beam spread.
Referring now to step 1420, for a receive beamforming operation each phase shifter in each antenna group is configured to apply its respective phase shift to a third signal received from the antenna element corresponding to that phase shifter.
Next, each delay element applies its respective time delay to a second signal that is received from the antenna group corresponding to that delay element (step 1425). The second signal is a combination of the phase-shifted third signals output by the corresponding phase shifters.
Returning to step 1415, the antenna groups form multiple beams based on the phase shifts and the time delays. In this case, however, the beams are receive beams, and are used to receive the third signal. The time delays are again configured to produce a beam spread in a first dimension of the 2D antenna array such that the multiple receive beams are formed in different directions. This allows for a combination of vertical beaming steering and horizontal beam spreading to generate a frequency dependent beam spread.
The above flowchart illustrates an example method or process that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods or processes illustrated in the flowcharts. For example, while shown as a series of steps, various steps could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.
Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. None of the description in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of patented subject matter is defined by the claims.
This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63/452,628 filed on Mar. 16, 2023, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63452628 | Mar 2023 | US |
