Semi active base station antenna system using time division duplexing

Abstract

A time-division duplex semi-active base station antenna system is provided. The time-division duplex semi-active base station antenna system includes: an antenna block comprising a plurality of transmit / receive antenna elements; a TxRx switching block that separates a transmit path and a receive path connected to the plurality of transmit / receive antenna elements by a timing signal for time-division control; and a TxRx timing recovery block that generates the timing signal from a transmit signal provided from a radio unit.

Description

Technology Field

[0001] The present invention relates to a time-division duplex semi-active base station antenna system, and more specifically, to a time-division duplex semi-active base station antenna system that can replace the multi-beam steering function with a simplified structure in a base station antenna system configured with MIMO (Multiple Input and Multiple Output). Background Technology

[0002] Generally, a cellular base station includes one or more antennas, a radio unit, and a baseband unit. The radio unit, also known as a Remote Radio Head (RRH), includes a transmitter pass with a power amplifier (PA), a receiver pass with a low-noise amplifier (LNA), and an RF channel filter.

[0003] FIG. 1 is a diagram illustrating the installation structure of a conventionally proposed base station antenna. When a radio signal of the RF frequency of a cellular system is transmitted through a coaxial cable extended to an RRH as shown in FIG. 1 (a), a significant amount of signal loss may occur. 5G NR (New Radio) mobile network cells operating at C-band frequencies may exhibit greater losses in capacity and overall throughput data due to losses in interconnected cables and internal antenna feeders.

[0004] To solve the problem of high-frequency cable loss in the connection between the RRH and the antenna, a structure has been proposed in which the RRH is connected directly below the antenna on the tower as shown in Fig. 1 (b). Additionally, as shown in Fig. 1 (c), an antenna structure has been presented in Patent Document 1 in which the wireless transceiver (Tx / Rx chain) is fully integrated with each antenna array radiator unit and the wireless transceiver of the RRH is integrated together with the patch antenna using a multi-layer PCB process.

[0005] The integrated antenna solutions of Fig. 1 (b) and (c) were able to improve data transmission speed, capacity, and coverage expansion by reducing losses in interconnected coaxial cables. However, since radio equipment and antennas are allocated to the top of base station towers, problems such as a lack of installation space in the multi-antenna era, increased installation costs due to the high cost of integrated active antennas, and increased difficulty in maintenance may arise.

[0006] In particular, massive Multi Input Multi Output (m-MIMO) antennas such as the 32TRX and 64TRX aimed to improve transmission capacity, speed, and latency performance by integrating the radio unit and the antenna, but high initial installation costs became the main cause of delays in building a nationwide network. Furthermore, even when using m-MIMO antennas equipped with array antennas like the 32TRX and 64TRX, vertical and horizontal beam steering were often insufficient to realize theoretical performance, which only highlighted the disadvantages of m-MIMO antennas. Prior art literature

[0007] U.S. Published Patent US20180192508A1 "A Multi-Layer Printed Circuit Board and a Wireless Communication Node" The problem to be solved

[0008] The technical problem that the present invention aims to solve is to provide a semi-active antenna structure that can improve installation and operation costs for building a base station antenna network by solving RF loss of interconnected coaxial cables even when the equipment is on the ground and improving the uplink coverage and processing capacity of a 5G NR network comparable to m-MIMO.

[0009] Another technical problem that the present invention aims to solve is to provide a base station antenna system that can reduce the installation and operation costs of C-band 5G NR network deployment by meeting the increased transmission demand capacity and securing wide service coverage through precise sectoring, such as 4 sectors or 6 sectors.

[0010] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0011] An integrated base station antenna system of the time-division duplex method according to an embodiment of the present invention for solving the above technical problem comprises: an antenna block including a plurality of transmit / receive antenna elements; a TxRx switching block that separates a transmit path and a receive path connected to the plurality of transmit / receive antenna elements by a timing signal for time-division control; and a TxRx timing recovery block that generates the timing signal from a transmit signal provided from a radio unit.

[0012] In some embodiments of the present invention, the TxRx switching block may include a first switch and a second switch that selectively connect both ends of the transmission path and the reception path; and a low-noise amplifier that amplifies a received signal in the reception path.

[0013] In some embodiments of the present invention, the timing signal can connect the first switch and the second switch to the transmission path at a first time, connect the first switch and the second switch to the reception path at a second time other than the first time, and turn on the low-noise amplifier.

[0014] In some embodiments of the present invention, the TxRx switching block may be connected between an input / output terminal connected to a radio unit and an antenna block to form a transmission path and a reception path separated according to the timing signal.

[0015] In some embodiments of the present invention, a channel filter may be further included to separate the channels of a transmission signal output from the TxRx switching block and a reception signal provided to the switching block.

[0016] In some embodiments of the present invention, the TxRx switching block may be inserted into the antenna block and connected to each of the plurality of transmit / receive antenna elements.

[0017] In some embodiments of the present invention, the channel filter may be inserted between the plurality of transmit / receive antenna elements and the TxRx switching block.

[0018] In some embodiments of the present invention, a coupler may be further included to separate the transmission signal and provide it to the TxRx timing recovery block.

[0019] In some embodiments of the present invention, the TxRx timing recovery block may include a log amplifier and a detector.

[0020] In some embodiments of the present invention, the plurality of transmitting and receiving antenna elements are further included in a reflector arranged in a row, and the reflector includes one end and the other end bent at a certain angle in the direction of the plurality of transmitting and receiving antenna elements, so as to be able to adjust the horizontal beam width to 45 degrees.

[0021] In some embodiments of the present invention, the plurality of transmitting and receiving antennas are arranged side by side to form an antenna array of first to third columns, and the antenna arrays of the first, second, and third columns are fed with a weighting of the electric field amplitudes of 1:2:1 so that the horizontal beam width can be adjusted to 33 degrees.

[0022] In another embodiment of the present invention for solving the above technical problem, an integrated base station antenna system of the time-division duplex method comprises: an antenna block including a plurality of transmitting and receiving antenna elements; and a TxRx switching block that separates a transmitting path and a receiving path connected to the plurality of transmitting and receiving antenna elements by a timing signal for time-division control, wherein the switching block comprises a first switch and a second switch that selectively connect both ends of the transmitting path and the receiving path; and a low-noise amplifier that amplifies a receiving signal in the receiving path.

[0023] In some embodiments of the present invention, a TxRx timing recovery block that generates the timing signal from a transmission signal provided from a radio unit may be further included.

[0024] Specific details of other embodiments are included in the detailed description and drawings. Effects of the invention

[0025] A time-division duplex semi-active base station antenna system according to an embodiment of the present invention comprises a transmitting antenna and a receiving antenna composed of identical transmitting and receiving antenna elements, and separates the transmitting path and the receiving path through a timing signal obtained by timing recovery from the transmitting signal without the need to receive a timing signal from an external unit. This allows for direct connection without the need for integration with a conventional RRH, thereby providing excellent effects in reducing installation and maintenance costs.

[0026] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0027] FIG. 1 is a drawing for explaining the installation structure of a base station antenna according to the prior art. FIG. 2 is a drawing for explaining a time-division duplex semi-active base station antenna system according to an embodiment of the present invention. FIGS. 3a and 3b are drawings for illustrating a time-division duplex semi-active base station antenna system according to another embodiment of the present invention. FIG. 4 is a diagram illustrating the structure of an antenna array and a reflector included in a time-division duplex semi-active base station antenna system according to an embodiment of the present invention. FIG. 5 is a diagram illustrating an antenna array included in a time-division duplex semi-active base station antenna system according to an embodiment of the present invention. FIG. 6 is a diagram illustrating a micro-sectoring structure that can be applied to a semi-active base station antenna system according to an embodiment of the present invention. FIG. 7 is a diagram illustrating a beam pattern that can be obtained by a semi-active base station antenna system according to an embodiment of the present invention. Specific details for implementing the invention

[0028] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0029] When one component is referred to as being "connected to" or "coupled to" another component, it includes cases where it is directly connected or coupled to the other component, or cases where another component is interposed. Conversely, when one component is referred to as being "directly connected to" or "directly coupled to" another component, it indicates that no other component is interposed. "And / or" includes each of the mentioned items and all combinations of one or more of them.

[0030] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0031] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, it goes without saying that the "first component" mentioned below may be the "second component" within the technical scope of the present invention.

[0032] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0033] FIG. 2 is a drawing for explaining a time-division duplex semi-active base station antenna system according to an embodiment of the present invention.

[0034] Referring to FIG. 2, a time-division duplex semi-active base station antenna system according to an embodiment of the present invention may include an antenna block (110) comprising a plurality of transmitting and receiving antenna elements, a TxRx switching block (120) that separates a transmitting path and a receiving path connected to the plurality of transmitting and receiving antenna elements by a timing signal for time-division control, and a TxRx timing recovery block (130) that generates the timing signal from a transmitting signal provided from a radio unit.

[0035] The antenna block (110) may include a phase variable (PS(n / 1)) and a plurality of transmit / receive antenna elements (AE1~AEn). The transmit / receive antenna elements (AE1~AEn) of the antenna block (110) may be arranged on a reflector to form a specific arrangement. As indicated by their names, the transmit / receive antenna elements (AE1~AEn) are used for both transmission and reception, and thus the same antenna element may be used for both the uplink and the downlink.

[0036] The TxRx switching block (120) is controlled by a timing signal provided by the TxRx timing recovery block (130) to separate the transmission path (Tx) and the reception path (Rx). The TxRx switching block (120) can connect the first switch (S1) and the second switch (S2) to the transmission path (Tx) in the case of a downlink connection between the coupler (131) and the channel filter (150), and connect the first switch (S1) and the second switch (S2) to the reception path (Rx) in the case of an uplink connection.

[0037] When the TxRx switching block (120) connects the received signal to the receiving path (Rx), the low-noise amplifier (LNA) is turned on to amplify the received signal with low noise. As illustrated, the low-noise amplifier (LNA) is not connected to the transmitting path (Tx) but is connected only to the receiving path (Rx) to amplify only the received signal. By amplifying the received signal by the low-noise amplifier (LNA), a reduction in the receivable signal level due to power loss caused by the high-frequency cable extending from the semi-active base station antenna system (1) to the ground can be prevented.

[0038] Meanwhile, the separation of the transmission path (Tx) and the reception path (Rx) by the TxRx switching block (120) through the connection of the first switch (S1) and the second switch (S2) can be performed in a time division duplexing manner by a timing signal provided by the TxRx timing recovery block (130). The TxRx timing recovery block (130) may include a coupler (131) and a TxRx timing recovery unit (132), and, for example, may include a log amplifier and a detector to generate a timing signal for controlling the TxRx switching block (120) from a transmission signal provided to the semi-active base station antenna system (1).

[0039] The timing signal may include a switch selection signal for controlling the first switch (S1) and the second switch (S2), and an amplifier control signal for controlling the turn-on of the low-noise amplifier (LNA). As previously explained, when the TxRx switching block (120) connects the transmission path (Tx) by the timing signal, the low-noise amplifier (LNA) is turned off, and when the reception path (Rx) is connected, the low-noise amplifier (LNA) is turned on.

[0040] A channel filter (150) is placed between the TxRx timing recovery block (130) and the antenna block (110) to prevent signal radiation to adjacent channels during transmission and to prevent saturation of the low-noise amplifier (LNA) by spurious signals entering from adjacent channels during reception.

[0041] The downlink operation by the semi-active base station antenna system (1) of FIG. 2 is performed as follows. A transmission signal input from a ground radio unit via a feed high-frequency cable is partially separated from the coupler (131) and provided to the TxRx timing recovery unit (132). The TxRx timing recovery unit (132) can generate a timing signal to connect the first and second switches (S1, S2) of the TxRx switching block (120) to the transmission path (Tx) by means of a combination of a log amplifier and a detector.

[0042] The transmission signal passing through the transmission path (Tx) of the TxRx switching block (120) and the channel filter (150) is input to the antenna block (110), passes through the phase variable (PS(n / 1)), and is radiated through a plurality of transmit / receive antenna elements (AE1~AEn). At this time, the transmission signals can be tilted in the direction indicated by the iRET (internal Remote Electric Tilt), and the tilt can be controlled, for example, according to the AISG v3.0 (Antenna Interface Standards Group) standard.

[0043] Meanwhile, the uplink operation by the semi-active base station antenna system (1) is performed as follows. A received signal received through a plurality of transmit / receive antenna elements (AE1~AEn) passes through a phase variable unit (PS(n / 1)) and a channel filter (150) and is provided to a TxRx switching block (120). Since the TxRx switching block (120) connects the receiving path (Rx) during the remaining time other than the time when the transmitting path (Tx) is connected by the timing signal generated by the TxRx timing recovery unit block (130), the received signal can be provided to a ground radio unit after passing through the receiving path (Rx) and being low-noise amplified.

[0044] In summary, the semi-active base station antenna system (1) according to an embodiment of the present invention is composed of a transmitting antenna and a receiving antenna with the same transmitting and receiving antenna elements, and separates the transmitting path and the receiving path through a timing signal obtained by timing recovery from the transmitting signal without the need to receive a timing signal from an external unit. This provides the effect of being directly connected to a conventional RRH as shown in (a) and (b) of FIG. 1.

[0045] In addition, when the receiving path is connected by the generated timing signal, the receiving sensitivity and uplink coverage can be improved by amplifying the received signal through a low-noise amplifier. That is, the base station antenna system of the present invention does not need to be implemented as an integrated unit with a radio unit such as an RRH, so the effect of reducing the aforementioned installation and maintenance costs can be excellent.

[0046] FIGS. 3a and 3b are drawings for illustrating a time-division duplex semi-active base station antenna system according to another embodiment of the present invention.

[0047] Referring to FIG. 3a, the time-division duplex semi-active base station antenna system (2) according to another embodiment of the present invention differs from the embodiment of FIG. 2 in that the TxRx switching blocks (220-1 to 220-n) and channel filters (250-1 to 250-n) are inserted inside the antenna block (210). In this regard, the differences from the previously described embodiment will be explained in detail, and descriptions of redundant elements will be omitted.

[0048] Specifically, the TxRx switching blocks (220-1 to 220-n) and channel filters (250-1 to 250-n) can be connected to each of the multiple transmit / receive antenna elements (AE1 to AEn). That is, the TxRx switching block (220-1) and the channel filter (250-1) are connected to each transmit / receive antenna element (AE1).

[0049] Accordingly, the timing signal generated from the transmission signal and provided from the timing recovery block (230) is provided to each TxRx switching block (220-1 to 220-n) so that the transmission path and the reception path can be separated. However, since the timing signal provided to the multiple TxRx switching blocks (220-1 to 220-n) is the same, when one switching block is controlled by the timing signal to connect the transmission path, the remaining switching blocks also connect the transmission path.

[0050] The downlink operation of the semi-active base station antenna system (2) of FIG. 3 is performed as follows. A transmission signal connected from a ground radio unit via a feed high-frequency cable is partially separated from the coupler (231) and provided to the timing recovery unit (232). The timing recovery unit (232) can generate a timing signal to connect the first and second switches (S1, S2) of a plurality of TxRx switching blocks (220-1 to 220-n), each connected to a plurality of transmit / receive antenna elements (AE1 to AEn) by a combination of a log amplifier and a detector, to a transmission path (Tx).

[0051] The transmission signal is input into the antenna block (210) and passes through the phase variable (PS(n / 1)). Depending on the tilt control of the iRET, it is distributed to the transmission paths of a plurality of TxRx switching blocks (220-1 to 220-n) and can be radiated into free space through channel filters (250-1 to 250-n) and transceiver antenna elements (AE1 to AEn).

[0052] Meanwhile, the uplink operation by the semi-active base station antenna system (2) is performed as follows. The received signal received through a plurality of transmit / receive antenna elements (AE1~AEn) passes through a channel filter (250-1~250-n) and is provided to the TxRx switching block (220-1~220-n). Since the TxRx switching block (220-1~220-n) connects the receiving path (Rx) during the remaining time other than the time when the transmitting path (Tx) is connected by the timing signal generated by the timing recovery block (230), the received signal passes through the receiving path (Rx), is low-noise amplified, and then passes through a phase variable unit (PS(n / 1)) and a coupler (231) to be provided to a radio unit on the ground.

[0053] The semi-active base station antenna system (2) according to the embodiment of FIG. 3 can guarantee even internal antenna feeder losses that occur during the distribution process through a phase variable (PS(n / 1)) as a plurality of TxRx switching blocks (220-1 to 220-n) are connected to each of a plurality of transmit / receive antenna elements (AE1 to AEn). Accordingly, by compensating for not only power loss caused by the feed cable but also internal antenna losses that are not easily apparent, such as the aforementioned feeder loss, antenna gain can be optimized and uplink performance can be improved.

[0054] Referring to FIG. 3b, in some other embodiments of the present invention, channel filters (250-1 to 250-n) may be configured to be connected to the downstream end of the receiving path (Rx), that is, between the phase variable (PS(n / 1)) and a plurality of switching blocks (220-1 to 220-n). If TX and RX timing control between 5G NR service providers can be performed simultaneously in time, the problem of saturation of the receiving low-noise amplifier due to leakage electromagnetic waves from adjacent providers can be eliminated. In this case, by placing the channel filters (250-1 to 250-n) after the low-noise amplifier (LNA) in the receiving path (Rx), the receiving antenna gain is improved by the insertion loss of the channel filters (250-1 to 250-n), and the uplink receiving sensitivity and coverage can be improved.

[0055] FIG. 4 is a diagram illustrating the structure of an antenna array and a reflector included in a time-division duplex semi-active base station antenna system according to an embodiment of the present invention.

[0056] Referring to FIG. 4, an antenna block (110, 210) according to an embodiment of the present invention may include a reflector (300) that supports a plurality of transmit / receive antenna elements (AE1~AEn) arranged in a row as in (b). The reflector (300) may include one end and the other end (310) that are bent at a certain angle in the direction of the plurality of transmit / receive antenna elements (AE). Through such a structure, the horizontal beam steering function implemented by m-MIMO can be simplified and implemented. In addition, the vertical direction may be arranged to have an aperture size equal to or greater than that of a conventional 4T4R antenna or m-MIMO antenna.

[0057] FIG. 5 is a diagram illustrating an antenna array included in a time-division duplex semi-active base station antenna system according to an embodiment of the present invention.

[0058] Referring to Fig. 5, three rows of dual-polarized patch antennas are arranged, and interference with adjacent cells can be improved by feeding the amplitudes of the electric fields of the three dual-polarized patch antennas with a 1:2:1 weighting according to the binomial distribution feeding theory.

[0059] According to the antenna arrangement and feeding structure of FIGS. 4 and 5, the semi-active base station antenna system of the present invention can have beam steering functions in the horizontal and vertical directions simplified, and combined with the structure of FIGS. 2 and 3, it can have uplink coverage performance comparable to the existing 32TRX m-MIMO.

[0060] FIG. 6 is a diagram illustrating a micro-sectoring structure that can be applied to a semi-active base station antenna system according to an embodiment of the present invention.

[0061] Referring to FIG. 6, FIG. 6(a) shows a structure with a 4-sector structure applied, where the horizontal beam width is controlled to 45 degrees by applying the reflector structure of FIG. 4, and FIG. 6(b) shows a structure where the horizontal beam width is controlled to 33 degrees by applying the feed and placement structure of FIG. 5. In the case of FIG. 6(b), there are no side lobes, so interference with adjacent cells is reduced, and as the energy efficiency of the system is improved, a 6-sector structure is applied, so the transmission capacity of the system can be improved.

[0062] FIG. 7 is a diagram illustrating a beam pattern that can be obtained by a semi-active base station antenna system according to an embodiment of the present invention.

[0063] Referring to FIG. 7, the diagram illustrates that by arranging two dual-polarized patch antennas in opposite directions around a reflector and feeding them in equal phase, a horizontal pattern (Fig. 7 (a)) and a vertical pattern (Fig. 7 (b)) of a pseudo-omnidirectional omnidirectional with a horizontal beam width of nearly 360 degrees are obtained. The structures of FIG. 6 and 7 are combined with the semi-active antenna structures of FIG. 2 and 3 to reduce the installation and operation costs of a 5G NR network through various sector divisions.

[0064] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. Explanation of the symbols

[0065] 1, 2: Semi-active base station antenna system 110, 210: Antenna block 120, 220: TxRx switching block 130, 230: TxRx timing recovery block 131, 231: Coupler 150, 250: Channel Filter

Claims

Claim 1 A time-division duplex semi-active base station antenna system comprising: an antenna block including a plurality of transmit / receive antenna elements; a TxRx switching block that separates a transmit path and a receive path connected to the plurality of transmit / receive antenna elements by a timing signal for time-division control; and a TxRx timing recovery block that generates the timing signal from a transmit signal provided from a radio unit, wherein the base station antenna system is characterized in that, in a state where a control line for receiving a separate TDD timing control signal from the radio unit is not connected, the TxRx timing recovery block switches the transmit / receive path of the TxRx switching block using the timing signal generated by itself from the transmit signal. Claim 2 A time-division duplex semi-active base station antenna system according to claim 1, wherein the TxRx switching block comprises: a first switch and a second switch that selectively connect both ends of the transmission path and the reception path; and a low-noise amplifier that amplifies a received signal in the reception path. Claim 3 In claim 2, the timing signal connects the first switch and the second switch to the transmission path at a first time, connects the first switch and the second switch to the reception path at a second time other than the first time, and turns on the low-noise amplifier, a time-division duplex semi-active base station antenna system. Claim 4 In claim 1, the TxRx switching block is connected between an input / output terminal connected to a radio unit and an antenna block to form a transmission path and a reception path separated according to the timing signal, in a time-division duplex semi-active base station antenna system. Claim 5 A time-division duplex semi-active base station antenna system according to claim 1, further comprising a channel filter that separates the channels of a transmission signal output from the TxRx switching block and a reception signal provided to the TxRx switching block. Claim 6 In claim 5, the TxRx switching block is inserted into the antenna block and connected to each of the plurality of transmit / receive antenna elements, in a time-division duplex semi-active base station antenna system. Claim 7 In claim 6, the channel filter is inserted between the plurality of transmit / receive antenna elements and the TxRx switching block, in a time-division duplex semi-active base station antenna system. Claim 8 A time-division duplex semi-active base station antenna system according to claim 1, further comprising a coupler that separates the transmission signal and provides it to the TxRx timing recovery block. Claim 9 In claim 1, the TxRx timing recovery block comprises a log amplifier and a detector, a time-division duplex semi-active base station antenna system. Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete

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