Distributed antenna system

Abstract

To provide a distributed antenna system that can deliver stable communication quality without installing new base stations at the facility. [Solution] The distributed antenna system comprises one or more master units that receive radio waves from a base station, one or more repeaters that distribute radio waves from the base station to a communication area, and one or more slave units that connect one or more antennas to provide the communication area. The base station and master units are installed at the first facility. The base station is connected to the master unit via a first communication path. The repeaters and slave units are installed at a second facility, which is different from the first facility and does not have a base station. The repeaters are connected to the slave units via a third communication path. At the second facility, the repeaters of the distributed antenna system are configured to be connected to the master unit at the first facility via an optical transmission path, which is a second communication path.

Description

[Technical Field]

[0001] The technology disclosed herein relates to a distributed antenna system. [Background technology]

[0002] In recent years, with the advancement of communication technologies such as 5G (5th Generation), communication speed, communication capacity, and the number of connected devices have increased dramatically. Due to their convenience, there is a desire for their use to be promoted in a wider range of environments in society. On the other hand, such communication technologies have several challenges. One of them is the characteristics of radio waves. For example, 5G radio waves are more susceptible to obstacles than 4G (4th Generation) radio waves. Therefore, radio waves do not easily reach shielded environments such as inside buildings. Thus, in order to utilize advanced communication technologies in society, it is essential to provide stable communication quality in places where radio waves do not easily reach. As one solution to this problem, a Distributed Antenna System (DAS) has been proposed. A Distributed Antenna System is a system that expands the communication area by distributing radio waves from a base station using a predetermined communication control device (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-140667 [Overview of the project] [Problems that the invention aims to solve]

[0004] For example, large facilities often have base stations installed by each telecommunications carrier to ensure consistent communication quality within the facility. On the other hand, smaller or older facilities often do not have base stations. Therefore, it is desirable to be able to provide stable communication quality even in facilities that do not currently have base stations, without having to install new ones.

[0005] The technology disclosed herein aims to provide a distributed antenna system that can deliver stable communication quality without requiring the installation of new base stations at a facility. [Means for solving the problem]

[0006] The technology disclosed herein employs the following technical means to solve the above-mentioned problems. The claims and the reference numerals in parentheses in this section are examples that indicate the correspondence with the specific means described in the embodiments later described below as one aspect. Therefore, they do not limit the technical scope of this disclosure.

[0007] A distributed antenna system (200), which is one aspect of the technology of this disclosure, is a system that distributes radio waves from a base station (90) to extend the communication area (NA). The distributed antenna system comprises one or more master units (201), one or more repeaters (202), and one or more slave units (203). The master units receive radio waves from the base station. The repeaters distribute radio waves from the base station to the communication area. The slave units connect one or more antennas to provide the communication area. The base station and the master units are installed in a first facility (10), and the base station is connected to the master unit via a first communication channel (Ta). The repeaters and slave units are installed in a second facility (20), which is different from the first facility and does not have a base station, and the repeaters are connected to the slave units via a third communication channel (Tc). The repeaters in the second facility are configured to be connected to the master unit in the first facility via an optical transmission path which is a second communication channel (Tb). [Effects of the Invention]

[0008] According to one aspect of the technology of this disclosure, the distributed antenna system is configured such that a master unit at a first facility where a base station is already installed and a repeater at a second facility where a base station is not installed are connected by an optical transmission path. This makes it possible to provide a distributed antenna system that can achieve stable communication quality without installing a new base station at the second facility. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of the distributed antenna system in the facility. [Figure 2] Figure 2 shows an example of a distributed antenna system configuration. [Figure 3] Figure 3 shows an example configuration of a distributed antenna system according to the first embodiment. [Figure 4] Figure 4 shows an example of the connection of a distributed antenna system according to the first embodiment. [Figure 5] Figure 5 shows an example configuration of the master unit (MU) of the distributed antenna system according to the first embodiment. [Figure 6] Figure 6 shows an example configuration of a distributed antenna system according to the second embodiment. [Figure 7] Figure 7 shows an example configuration of a distributed antenna system according to the third embodiment. [Modes for carrying out the invention]

[0010] Hereafter, embodiments relating to the technology of this disclosure will be described with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0011] <System Outline Configuration> Figure 1 is a schematic diagram of the distributed antenna system 100 in facility 10. Figure 1 shows an example of a large-scale facility 10 in a large building such as a high-rise building. In facility 10, a distributed antenna system 100, such as the one shown in Figure 1, is constructed to provide stable communication quality on each floor.

[0012] In Figure 1, a base station is denoted as "Base Station: BS," and multiple base stations corresponding to each telecommunications carrier are represented as (BS-1), (BS-2), ... (BS-n). Multiple base stations (BS-1)901~(BS-n)90 n For example, it is installed in the underground equipment room of facility 10, which is capable of supplying power. Subsequently, multiple base stations (BS-1)901~(BS-n)90 n When referring to them collectively, they are simply called "Base Station (BS) 90".

[0013] A base station (BS) 90 corresponds to the terminal equipment of a mobile communication network built by a telecommunications carrier. A mobile communication network is constructed by connecting many base stations (BS) 90s and switching centers to each other via optical transmission paths (e.g., "optical fibers").

[0014] (Distributed antenna system) The basic configuration of the distributed antenna system 100 consists of one master unit (MU) 101 installed adjacent to the base station (BS) 90, and one or more repeaters (HU-1) 1021 to (HU-n) 102 installed on each floor. n And, one or more sub-units (RU-1-1) 103 are installed on each floor. 1-1 ~(RU-nn)103 n-n It has, and

[0015] (Main unit) In FIG. 1, the master unit is represented as "Master Unit: MU". The master unit (MU) 101 is a device including, for example, one or more processors (not shown), one or more memories (not shown), one or more storages (not shown), and one or more communication I / Fs (not shown). The master unit (MU) 101 is a communication control device that receives the radio signal (RF signal) of the base station (BS) 90. The master unit (MU) 101 converts the radio signal of each frequency band received from the base station (BS) 90 into an optical signal and transmits it. Therefore, the communication I / F of the master unit (MU) 101 includes at least an interface capable of receiving the radio signal of each frequency band and an interface capable of transmitting the converted optical signal.

[0016] In order to achieve high-speed signal processing, the master unit (MU) 101 may include a plurality of communication control devices each including a processor, a memory, a storage, and a communication I / F, which are connected to each other.

[0017] The master unit (MU) 101 is a common device for a plurality of base stations (BS-1) 901 to (BS-n) 90 n and is connected to the plurality of base stations (BS-1) 901 to (BS-n) 90 n via the communication I / F through a plurality of communication paths Ta1 to Ta n Here, the plurality of communication paths Ta1 to Ta n refer to coaxial transmission lines (such as "coaxial cables"). Since the base station (BS) 90 and the master unit (MU) 101 are arranged adjacent to each other, the distance between their devices is short. Therefore, even if the plurality of communication paths Ta1 to Ta n are coaxial transmission lines, they will not have an adverse effect on the communication quality.

[0018] ]>Specifically, between the plurality of base stations (BS1) 901 to (BSn) 90 n and one master unit (MU) 101, there are a first-1 communication path Ta1 corresponding to the base station (BS1) 901 of the first communication carrier, a first-2 communication path Ta2 corresponding to the base station (BS2) 902 of the second communication carrier, and a first-N communication path Ta corresponding to the base station (BSn) 90 n of the Nth communication carrier.n A set of multiple communication channels Ta1 to Ta are provided. n When referring to them collectively, they are simply called "First Communication Channel Ta".

[0019] (Repeater) In Figure 1, repeaters are referred to as "Hub Unit: HU," and multiple repeaters installed on each floor are represented as (HU-1), (HU-2), ... (HU-n). For example, on the 1st floor, one repeater (HU-1) 1021 is installed between the master unit 101 and the expanded 1st communication area NA1. On the 2nd floor, one repeater (HU-2) 1022 is installed between the master unit 101 and the expanded 2nd communication area NA2. On the Nth floor, the master unit 101 and the expanded Nth communication area NA n There is one repeater (HU-n) 102 between them. n A repeater (HU-1)1021~(HU-n)102 is installed. n When referring to them collectively, they are simply called "Repeater (HU) 102". Also, the 1st communication area NA1 to the Nth communication area NA n When referring to them collectively, the term "communication area NA" is used.

[0020] The repeater (HU) 102 is a device comprising, for example, one or more processors (not shown), one or more memories (not shown), one or more storage (not shown), and one or more communication interfaces (not shown). The repeater (HU) 102 is a communication control device that distributes (relays) signals between one master unit (MU) 101 and an extended communication area NA. The repeater (HU) 102 forwards optical signals received from the master unit (MU) 101 to other repeaters and slave units. Therefore, the communication interface of the repeater (HU) 102 includes at least an interface capable of sending and receiving optical signals.

[0021] The repeater (HU) 102 may be configured by connecting multiple communication control devices, each equipped with a processor, memory, storage, and a communication interface, to each other in order to achieve high-speed signal processing.

[0022] Multiple repeaters (HU-1) 1021~(HU-n) 102 n The common master unit (MU) 101 communicates via a communication interface through predetermined communication paths Tb1 to Tb n The connection is made via the designated communication channels Tb1 to Tb. n This refers to optical transmission lines, such as optical fibers.

[0023] Specifically, repeater (HU-1) 1021 installed on the first floor is connected to the master unit 101 via the 2-1 communication channel Tb1. Repeater (HU-2) 1022 installed on the second floor is connected to repeater (HU-1) 1021 installed on the first floor via the 2-2 communication channel Tb2. In other words, each repeater (HU-1) 1021 to (HU-n) 102 n These are connected in a cascade. Subsequently, multiple communication channels Tb1~Tb n When referring to them collectively, they are simply called "Second Communication Channel Tb".

[0024] (Handset) In Figure 1, the slave units are referred to as "Remote Unit: RU," and the multiple slave units installed on each floor are represented as (RU-1-1), (RU-2-2), ... (RU-nn). For example, on the first floor, there are multiple slave units (RU-1-1) 103 between the repeater (HU-1) 1021 and the extended first communication area NA1. 1-1 ~(RU-1-n)103 1-n On the second floor, multiple slave units (RU-2-1) 103 are installed between the repeater (HU-2) 1022 and the expanded second communication area NA2. 2-1 ~(RU-2-n)103 2-n A repeater (HU-n) 102 is installed on the Nth floor. n The Nth communication area NA expands n Between them are multiple sub-units (RU-n-1) 103 n-1 ~(RU-nn)103 n-n It is installed. Subsequently, multiple sub-units (RU-1-1) 103 1-1 ~(RU-nn)103 n-n When referring to them collectively, they are simply called "Sub-unit (RU) 103".

[0025] The slave unit (RU) 103 is a device comprising, for example, one or more processors (not shown), one or more memories (not shown), one or more storage (not shown), and one or more communication interfaces (not shown). The slave unit (RU) 103 is a communication control device to which one or more antennas (not shown) are connected for providing an extended communication area NA. The slave unit (RU) 103 converts the optical signal received from the repeater (HU) 102 into radio signals for each frequency band. The slave unit (RU) 103 transmits the converted radio signals via one or more externally connected antennas. Therefore, the communication interface of the slave unit (RU) 103 includes at least an interface capable of receiving optical signals and an interface capable of transmitting radio signals for each frequency band.

[0026] The slave unit (RU) 103 may be configured by connecting multiple single communication control devices, each equipped with a processor, memory, storage, and a communication interface, to each other in order to achieve high-speed signal processing.

[0027] Multiple handsets (RU-1-1) 103 1-1 ~(RU-nn)103 n-n This involves multiple repeaters (HU-1)1021~(HU-n)102 n Then, via the communication I / F, through a predetermined communication channel Tc 1-1 ~Tc n-n The connection is made via the designated communication channel Tc. 1-1 ~Tc n-n This refers to optical transmission lines, such as optical fibers.

[0028] Specifically, multiple slave units (RU-1-1) 103 corresponding to the first communication area NA1 on the first floor. 1-1 ~(RU-1-n)103 1-n In a group of first slave units including one unit, slave unit (RU-1-1) 103 1-1 The repeater (HU-1) 1021 connects to the 3-1-1 communication channel Tc 1-1 It is connected as follows: Sub-unit (RU-1-2) 103 1-2 This is the handset (RU-1-1) 103 1-1 Channel 3-1-2 Tc 1-2They are connected. Multiple slave units (RU-2-1) 103 are connected to the second communication area NA2 on the second floor. 2-1 ~(RU-2-n)103 2-n In a second group of slave units including slave unit (RU-2-1) 103 2-1 The repeater (HU-2) 1022 connects to the 3rd-2-1st communication channel Tc 2-1 It is connected as follows: Sub-unit (RU-2-2) 103 2-2 The handset (RU-2-1) 103 2-1 Channel 3-2-2 Tc 2-2 It is connected in the Nth communication area NA on the Nth floor. n Multiple compatible sub-units (RU-n-1) 103 n-1 ~(RU-nn)103 n-n In a set of the Nth group of slave units including slave unit (RU-n-1) 103 n-1 This is the repeater (HU-n) 102 n to the 3rd-n-1 communication channel Tc n-1 It is connected as follows: Sub-unit (RU-n-2) 103 n-2 This is the handset (RU-n-1) 103 n-1 to the 3rd-n-2nd communication channel Tc n-2 They are connected.

[0029] In other words, each slave unit (RU-1-1) 103 1-1 ~(RU-nn)103 n-n These are cascaded for each expanding notification area NA. Subsequently, multiple communication channels Tc 1-1 ~Tc n-n When referring to them collectively, they are simply called "Third Communication Channel Tc".

[0030] <Example of antenna system construction> Figure 2 shows an example of the construction of a distributed antenna system 100. Figure 2(a) shows multiple slave units (RU-1-1) 103 connected in cascade. 1-1 ~(RU-1-n)103 1-n A distributed antenna system 100 is constructed by connecting a group of child units, including one of the above, to a single repeater (HU) 102. a An example of this is shown. On the other hand, Figure 2(b) shows multiple slave units (RU-1-1) 103 connected in cascade.1-1 ~(RU-1-n)103 1-n A set of first slave units including and multiple cascaded slave units (RU-2-1) 103 2-1 ~(RU-2-n)103 2-n A distributed antenna system 100 is constructed by star-connecting one set of second child units (including two sets of child units) to one repeater (HU) 102. b An example is shown in Figure 2(b) of the distributed antenna system 100. b This is the distributed antenna system 100 in Figure (a) a This allows for a greater number of sub-units (RU) 103 per unit area and the installation of more antennas. Therefore, the communication area NA in Figure 2(b) b This refers to the communication area NA in Figure (a). a The connection points are more densely packed. This allows for stable communication quality to be provided to a larger number of communication terminals (not shown).

[0031] Thus, the configuration of the distributed antenna system 100 can be modified as appropriate depending on how the communication area NA is expanded and constructed in order to provide stable communication quality.

[0032] As described above, the distributed antenna system 100 is configured such that the master unit (MU) 101 receives radio waves from the base station (BS) 90, and transmits the received radio waves to the slave units (RU) 103 installed within the facility via the repeater (HU) 102. The distributed antenna system 100 is configured to extend the communication area NA by using the antenna installed on the slave units (RU) 103. With this configuration, stable communication quality can be provided to communication terminals located within the facility.

[0033] <Technology of this disclosure> The technology disclosed herein aims to promote the use of advanced communication technologies. Therefore, this disclosure provides a means to enable the distributed antenna system 100 described above to be used in a wider range of environments in society. In particular, the technology disclosed herein targets facilities where base stations (BS) 90 are not installed (hereinafter referred to as "second-class facilities" for convenience). Generally, the distributed antenna system 100 assumes that base stations (BS) 90 for each telecommunications carrier are installed within the facility where the system is installed. However, in society, second-class facilities where base stations (BS) 90 are not installed are more numerous than facilities 10 where base stations (BS) 90 are installed (hereinafter referred to as "first-class facilities" for convenience). One reason for the large number of second-class facilities is the difficulty in securing a place to install base stations (BS) 90. Smaller or older facilities may not have sufficiently large equipment rooms, making it impossible to secure space to install base stations (BS) 90 for each telecommunications carrier. Another reason for the large number of second-class facilities is the cost of installing base stations (BS) 90. In smaller or older facilities, the balance between the installation cost of base stations (BS) 90 and the number of users is poor, resulting in cost-effectiveness issues. One possible solution is to install base stations (BS) 90 for each telecommunications carrier within the second facility, similar to the first facility, and construct a distributed antenna system 100. However, many facilities lack the space to install base stations (BS) 90 and master units (MU) 101, and this is not practical from the standpoint of installation costs.

[0034] Therefore, even at the second facility, it is desirable from the perspective of promoting the use of advanced communication technologies that stable communication quality can be provided at the facility without installing a new base station (BS) 90. The technology disclosed herein was devised in view of the above points and provides a new solution.

[0035] <First Embodiment> Figure 3 shows an example configuration of the distributed antenna system 200 according to this embodiment. Figure 3 shows a first facility 10 on which a base station (BS) 90 is installed, and a second facility 20 on which a base station (BS) 90 is not installed. In this embodiment, a distributed antenna system 200 capable of providing stable communication quality at the second facility 20 will be described.

[0036] (Basic configuration) The distributed antenna system 200 according to this embodiment comprises a master unit (MU) 201, a repeater (HU) 202, and a slave unit (RU) 203, similar to the distributed antenna system 100 described above. The repeater (HU) 202 is connected to the slave unit (RU) 203 via a third communication channel Tc through a communication interface. For convenience, Figure 3 shows an example configuration in which there is one repeater (HU) 202 and one slave unit (RU) 203. The technology of this disclosure is not limited to this. At least multiple slave units (RU) 203 may be provided.

[0037] Assume that a first facility 10, which has a base station (BS) 90 installed, is located near a second facility 20, which does not have a base station (BS) 90. The first facility 10 is equipped with a base station (BS) 90 and a master unit (MU) 201, and the base station (BS) 90 is connected to the master unit (MU) 201 via a first communication channel Ta. In other words, the first facility 10 is in a state where it can distribute (relay) the radio waves of the base station (BS) 90 to the surrounding second facility 20 via the master unit (MU) 201.

[0038] Therefore, in this embodiment, the distributed antenna system 200 is configured to connect the repeater (HU) 202 to the master unit (MU) 201 of the first facility 10 via a second communication channel Tb. Furthermore, in this embodiment, the second communication channel Tb is an optical fiber (optical transmission line).

[0039] For example, the base station (BS) 90 and the master unit (MU) 201 are installed in the same facility and are adjacent to each other. Therefore, because the connection distance between the base station (BS) 90 and the master unit (MU) 201 is short, using a communication path other than optical fiber, such as a coaxial cable, will not significantly affect the communication quality. On the other hand, when the connection distance is greater than a certain distance, such as between facilities, using a communication path other than optical fiber will affect the communication quality (high-speed, high-capacity communication quality will decrease). For this reason, the distributed antenna system 200 according to this embodiment is configured to connect the repeater (HU) 202 to the master unit (MU) 201 of the first facility 10 with an optical transmission path such as an optical fiber. The distributed antenna system 200 may also be configured to connect the repeater (HU) 202 to the master unit (MU) 201 of the first facility 10 with a high-speed, high-capacity communication path equivalent to an optical transmission path.

[0040] Furthermore, when optical fiber is used for the second communication channel Tb, the communication interfaces of the master unit (MU) 201 of the first facility 10 and the repeater (HU) 202 of the second facility 20 are interfaces capable of transmitting and receiving optical signals at high speed and with large capacity.

[0041] As described above, the distributed antenna system 200 according to this embodiment is configured to connect a master unit (MU) 201 at a first facility 10 where a base station (BS) 90 is installed, and a repeater (HU) 202 at a second facility 20 where a base station (BS) 90 is not installed, via an optical transmission path. The distributed antenna system 200 receives radio waves from the base station (BS) 90 from the first facility 10 via the repeater (HU) 202, and transmits the received radio waves to a slave unit (RU) 203 installed at the second facility 20, thereby distributing (relaying) the radio waves from the first facility 10 to the second facility 20. The distributed antenna system 200 is configured to extend the communication area NA by using the antenna installed at the slave unit (RU) 203.

[0042] According to this configuration, even in the second facility 20 where the base station (BS) 90 is not installed, stable communication quality can be provided to the communication terminals existing in the facility without installing a new base station (BS) 90. As a result, the distributed antenna system 200 according to the present embodiment can provide stable communication quality by inexpensive means even in the second facility 20 where there is no space to install the base station (BS) 90 or the master unit (MU) 201.

[0043] (Connection Configuration) FIG. 4 is a diagram showing a connection example of the distributed antenna system 200 according to the present embodiment. In FIG. 4, a plurality of repeaters (HU-1) 2021 to (HU-n) 202 n are shown as being star-connected to one master unit (MU) 201. Specifically, in the distributed antenna system 200, the repeater (HU-1) 2021 is connected to the master unit (MU) 201 in the first facility 10 via the second-1 communication path Tb1. Also, the repeater (HU-2) 2022 is connected to the master unit (MU) 201 in the first facility 10 via the second-2 communication path Tb2. Also, the repeater (HU-n) 202 n is connected to the master unit (MU) 201 in the first facility 10 via the second-n communication path Tb n . Thus, in the distributed antenna system 200, each repeater (HU-n) 202 1-1 ~202 1-n is connected to the common master unit (MU) 201 in the first facility 10 via each second communication path Tb1 to Tb n . Note that each of the second communication paths Tb1 to Tb n is an optical fiber.

[0044] Furthermore, in the same figure, an example in which a plurality of slave units (RU-1-1) 203 1-1 ~(RU-1-n) 203 1-n are star-connected to one repeater (HU-1) 2021 is shown. Specifically, in the distributed antenna system 200, the slave unit (RU-1-1) 203 1-1 is connected to the repeater (HU-1) 2021 via the third-1-1 communication path Tc 1-1 . Also, the slave unit (RU-1-n) 203 1-nThe repeater (HU) 2021 is connected to the 3-1-n communication path Tc 1-n Further, the slave unit (RU-2-1) 203 2-1 is connected to the repeater (HU-2) 2022 via the 3-2-1 communication path Tc 2-1 Also, the slave unit (RU-2-n) 203 2-n is connected to the repeater (HU) 2022 via the 3-2-n communication path Tc 2-n Moreover, the slave unit (RU-n-1) 203 n-1 is connected to the repeater (HU-n) 202 n via the 3-n-1 communication path Tc n-1 Also, the slave unit (RU-n-n) 203 n-n is connected to the repeater (HU) 202 n via the 3-n-n communication path Tc n-n In this way, in the distributed antenna system 200, each slave unit (RU-1-1) 203 1-1 ~(RU-1-n) 203 1-n is connected to the common repeater (HU-1) 2021 via each of the 3-1 communication paths Tc 1-1 ~Tc 1-n As a result, an extended first communication area NA1 is constructed. Also, each slave unit (RU-2-1) 203 2-1 ~(RU-2-n) 203 2-n is connected to the common repeater (HU-2) 2022 via each of the 3-2 communication paths Tc 2-1 ~Tc 2-n As a result, an extended second communication area NA2 is constructed. Also, each slave unit (RU-n-1) 203 n-1 ~(RU-n-n) 203 n-n is connected to the common repeater (HU-n) 202 n via each of the 3-n communication paths Tc n-1 ~Tc n-n As a result, an extended Nth communication area NA n is constructed. Note that the 3-1 communication path Tc 1-1 ~the 3-n communication path Tc n-n are optical fibers.

[0045] As described above, the distributed antenna system 200 according to this embodiment has a basic connection configuration in which repeaters (HUs) 202 and slave units (RUs) 203 are connected in a star configuration. However, the distributed antenna system 200 is not limited to this connection configuration. As mentioned above, the system 200 may also have a configuration in which repeaters (HUs) 202 and slave units (RUs) 203 are connected in a cascade configuration. Furthermore, the system 200 may be a system constructed by combining star and cascade connections.

[0046] Furthermore, in the distributed antenna system 200 according to this embodiment, it is not necessary to install repeaters (HUs) 202 on each floor of the second facility 20. In this system 200, for example, one repeater (HU) 202 is configured to ensure communication quality for a communication area NA of three floors. Therefore, for example, in the case of a 15-story second facility 20, the distributed antenna system 200 according to this embodiment only needs to have five repeaters (HUs) 202. Thus, the number of repeaters (HUs) 202 in this system 200 should be such that stable communication quality can be provided in the expanded communication area NA on each floor of the second facility 20.

[0047] (Variations in connection configuration) The distributed antenna system 200 according to the above embodiment has been described in a configuration that includes a repeater (HU) 202, but is not limited thereto. For example, the distributed antenna system 200 may consist only of a slave unit (RU) 203. In this case, the slave unit (RU) 203 is configured to also function as a repeater (HU) that distributes (relays) signals between the master unit (MU) 201 and the expanding communication area NA.

[0048] Therefore, the distributed antenna system 200 may be configured such that the master unit (MU) 201 of the first facility 10 is connected to the slave unit (RU) 203 of the second facility 20 via the second communication channel Tb.

[0049] (Frequency band extension configuration) Figure 5 shows an example configuration of the master unit (MU) 201 of the distributed antenna system 200 according to this embodiment. Figure 5 shows an example in which the master unit (MU) 201 has a bandwidth expansion function to support communication in multiple frequency bands #1 to #n provided by the base station (BS) 90.

[0050] The frequency bands supported by base station (BS) 90 include, for example, three frequency bands such as 700 MHz, 1.7 GHz, and 3.7 GHz. The use of these frequency bands for communication is strictly controlled by the supervising ministry (Ministry of Internal Affairs and Communications). Therefore, telecommunications carriers obtain permission from the supervising ministry to use these frequency bands and provide communication services. Thus, base station (BS) 90 provides communication services for each frequency band #1 to #n authorized for use by each telecommunications carrier, using multiple communication devices 911 to 91 n The master unit (MU) 201 according to this embodiment has a bandwidth expansion function to support communication in multiple frequency bands #1 to #n, and includes an expansion unit 211 to realize this function. The master unit (MU) 201 also includes a basic unit 212 for controlling the bandwidth expansion function.

[0051] The expansion unit 211 has multiple communication devices 21111~2111 depending on the number of corresponding frequency bands. n The configuration allows for expansion, enabling bandwidth expansion. Subsequently, multiple communication devices 21111~2111 n When referring to them collectively, they are simply called "communication device 2111". The expansion unit 211 is configured so that one communication device 2111 can be installed for each frequency band. Therefore, in the expansion unit 211 according to this embodiment, it is sufficient to install a number of communication devices 2111 for each frequency band #1 to #n corresponding to the number of frequency bands #1 to #n provided by the base station (BS) 90.

[0052] The expansion unit 211 according to this embodiment is configured to support communication in up to 32 frequency bands as a result of the above expansion configuration. In other words, the expansion unit 211 is configured to accommodate up to 32 communication devices 2111.

[0053] Communication devices 21111~2111 installed in the expansion unit 211 n This refers to the communication equipment 911-91 installed at base station (BS) 90. n And, via the communication interface, multiple communication channels Ta1~Ta n The connection is established via the following: Each communication device 21111~2111 of the master unit (MU) 201. n This refers to the communication equipment 911-91 of the base station (BS) 90, which corresponds to multiple frequency bands #1-#n provided by the base station (BS) 90. n The devices are connected via separate communication channels. More specifically, the communication device 21111 installed for frequency band #1 on the master unit (MU) 201 side is connected to the communication device 911 for frequency band #1 on the base station (BS) 90 side via the 1-1 communication channel Ta1. The communication device 21112 installed for frequency band #2 on the master unit (MU) 201 side is connected to the communication device 912 for frequency band #2 on the base station (BS) 90 side via the 1-2 communication channel Ta2. The communication device 21113 installed for frequency band #3 on the master unit (MU) 201 side is connected to the communication device 913 for frequency band #3 on the base station (BS) 90 side via the 1-3 communication channel Ta3. n is the first-n communication channel Ta n via the communication device 91 in frequency band #n on the base station (BS) 90 side n It connects to the network.

[0054] The basic unit 212 includes a control device 2121. The control device 2121 controls each of the communication devices 21111 to 2111 of the expansion unit 211. n It is connected via a predetermined transmission path through a communication interface. The control device 2121 performs, for example, access control and error detection (communication monitoring) of the communication device 2111.

[0055] In this embodiment, the slave unit (RU) 203 is connected to the master unit (MU) 201, which has the above-described bandwidth expansion function, either directly without the repeater (HU) 202, or via the repeater (HU) 202. In this embodiment, when the slave unit (RU) 203 is connected directly to the master unit (MU) 201, the slave unit (RU) 203 and the master unit (MU) 201 are connected by an optical transmission path (optical fiber). When the slave unit (RU) 203 is connected to the master unit (MU) 201 via the repeater (HU) 202, the repeater (HU) 202 and the master unit (MU) 201 are connected by an optical transmission path (optical fiber).

[0056] In this embodiment, the slave unit (RU) 203 is configured to transmit and receive signals in each frequency band #1 to #n that has been expanded by the expansion unit 211 (bandwidth expansion function) of the master unit (MU) 201. In other words, the slave unit (RU) 203 is configured to transmit and receive all signals in the multiple frequency bands #1 to #n provided by the base station (BS) 90. The repeater (HU) 202 is configured to be independent of the frequency band.

[0057] According to this configuration, the distributed antenna system 200 according to this embodiment has multiple frequency bands #1 to #n provided by the base station (BS) 90, and communication areas NA1 to NA n This can be constructed within the facility. As described above, the configuration of this embodiment can support communication in up to 32 frequency bands. More specifically, the distributed antenna system 200 according to this embodiment is intended to support communication in a total of eight frequency bands, in addition to the three frequency bands of 700 [MHz], 1.7 [GHz], and 3.7 [GHz], as well as 400 [MHz] (band for commercial radio), 900 [MHz], 2.1 [GHz], 3.5 [GHz], and 4.5 [GHz].

[0058] Thus, the distributed antenna system 200 according to this embodiment can support communication in multiple frequency bands, more than three in number. Furthermore, even if the use of communication in previously unexplored frequency bands is authorized and a new communication service is launched by a telecommunications carrier, the distributed antenna system 200 can flexibly respond by adding communication devices 2111 to the master unit (MU) 201.

[0059] (Configuration for long-distance optical transmission lines) As described above, the distributed antenna system 200 according to this embodiment is configured to connect the master unit (MU) 201 of the first facility 10 and the repeater (HU) 202 or slave unit (RU) 203 of the second facility 20 with a second communication channel Tb which is an optical transmission line (optical fiber).

[0060] In such a configuration, the transmission distance between the first facility 10 and the second facility 20 becomes an issue. In the distributed antenna system 200, it is desirable that stable communication quality can be provided at the second facility 20 even in environments where the distance between the first facility 10 and the second facility 20 is long (for example, in environments where the distance is 10 km or more). Therefore, in the distributed antenna system 200 according to this embodiment, each of the devices, the master unit (MU) 201, the repeater (HU) 202, and the slave unit (RU) 203, is equipped with an SFP (Small Form-factor Pluggable) module that supports long-distance optical transmission.

[0061] An SFP module is a module that converts electrical signals into optical signals for optical communication transmission and reception. Optical fibers come in two types: single-mode and multimode. Single-mode fibers have a small core diameter and low light dispersion, making them suitable for long-distance optical transmission. Due to these characteristics, single-mode fibers are said to be capable of optical transmission over distances of up to several tens of kilometers. On the other hand, multimode fibers have a larger core diameter and higher light dispersion than single-mode fibers, making them unsuitable for long-distance optical transmission. However, because of their larger core diameter, multimode fibers are less prone to attenuation due to mismatches during connection. Due to these characteristics, multimode fibers are intended for optical transmission up to approximately 3 kilometers.

[0062] The SFP module according to this embodiment supports single-mode operation, taking into account the above-mentioned mode characteristics, such that the optical transmission distance between the master unit (MU) 201 and the repeater (HU) 202 or slave unit (RU) 203 is 10 km or more. In other words, this embodiment uses a configuration that employs single-mode fiber and a single-mode SFP module for long-distance transmission.

[0063] The optical reception sensitivity and optical output power of the single-mode SFP module used in this embodiment shall have performance values ​​necessary to achieve long-distance optical transmission of 10 km or more. Optical reception sensitivity (RX sensitivity) refers to the signal level received from the master unit (MU) 201. Optical output power (TX power) refers to the signal level output from the repeater (HU) 202 or the slave unit (RU) 203. The performance value of optical reception sensitivity shall be a value that falls within the reception power range of the long-distance transmission environment of 10 km or more that is to be realized. Similarly, the performance value of optical output power shall be a value that falls within the output power range of the long-distance transmission environment of 10 km or more that is to be realized. The performance values ​​of optical reception sensitivity and optical output power shall also be optimized using the optical fiber.

[0064] Furthermore, when the master unit (MU) 201 and the slave unit (RU) 203 are directly connected, a dynamic range suitable for this configuration is required. Dynamic range typically refers to the difference between the optical coupling output of the optical transmitting module or the maximum receiving sensitivity of the optical receiving module and the minimum receiving sensitivity of the optical receiving module (the difference between the maximum and minimum values). The wider the dynamic range (the larger the value), the more suitable it is for long-distance transmission. Therefore, the SFP module requires a large dynamic range to function in a configuration where the master unit (MU) 201 and the slave unit (RU) 203 are directly connected.

[0065] Thus, in the distributed antenna system 200 according to this embodiment, by using single-mode SFP modules for long-distance transmission, it is possible to achieve optical transmission paths of 10 km or more.

[0066] <Second Embodiment> Figure 6 shows an example configuration of the distributed antenna system 2001 according to this embodiment. Figure 6 shows a number of second facilities 201-20 that do not have base stations (BS) 90 installed around the first facility 10 where base stations (BS) 90 are installed. n An example configuration of the distributed antenna system 2001 is shown when such a component exists. For convenience, in the following description, the same reference numerals are used for components common to the first embodiment, and their explanations are omitted.

[0067] The distributed antenna system 2001 according to this embodiment is configured to connect the repeater (HU-1) 2021 of facility 2-1 201 to the master unit (MU) 201 of facility 1 10 via the 2-1 communication channel Tb1 (optical fiber). Furthermore, the distributed antenna system 2001 is configured to connect the repeater (HU-2) 2022 of facility 2-2 202 to the master unit (MU) 201 of facility 1 10 via the 2-2 communication channel Tb2 (optical fiber). In addition, the distributed antenna system 2001 is configured to connect to facility 2-n 20 n Repeater (HU-n) 202 n The second-n communication channel Tb is connected to the master unit (MU) 201 of the first facility 10. n The configuration uses optical fiber for connection.

[0068] In other words, the distributed antenna system 2001 according to this embodiment has a master unit (MU) 201 of one first facility 10 where a base station (BS) 90 is installed, and multiple second facilities 201-20 located around the first facility 10 where a base station (BS) 90 is not installed. n Each repeater (HU-1) 2021 ~ (HU-n) 202 n However, the configuration uses a star connection via optical fiber.

[0069] According to this configuration, multiple second facilities 201-20 where base station (BS) 90 is not installed n Even so, stable communication quality can be provided to communication terminals within each facility without installing new base stations (BS) 90 at each of the second facilities 20.

[0070] <Third Embodiment> Figure 7 shows an example configuration of the distributed antenna system 2002 according to this embodiment. Figure 7 shows that around the second facility 20 where the base station (BS) 90 is not installed, there are multiple first facilities 101 to 10 where the base station (BS) 90 is installed. n An example configuration of the distributed antenna system 2002 is shown when such a component exists. For convenience, in the following description, the same reference numerals are used for components common to the first and second embodiments, and their explanations are omitted.

[0071] In this embodiment, for example, a plurality of first facilities 101-10 n base stations of different telecommunications carriers (BS-1)901~(BS-n)90 n This assumes the construction of a distributed antenna system 2002 for the second facility 20, assuming each of the components is installed.

[0072] In this embodiment, the distributed antenna system 2002 is configured such that the repeater (HU-1) 2021 of the second facility 20 is connected to the master unit (MU-1) 2011 of the first-first facility 101 via the second-first communication channel Tb1 (optical fiber). The master unit (MU-1) 2011 of the first-first facility 101 is connected to the base station (BS-1) 901 of the first telecommunications carrier. Therefore, from the first-first facility 101, the radio waves from the base station (BS-1) 901 of the first telecommunications carrier are distributed (relayed) to the second facility 20 via the master unit (MU-1) 2011. Furthermore, the distributed antenna system 2002 is configured such that the repeater (HU-2) 2022 of the second facility 20 is connected to the master unit (MU-2) 2012 of the first-second facility 102 via the second-second communication channel Tb2 (optical fiber). The master unit (MU-2) 2012 of facility 1-2 102 is connected to the base station (BS-2) 902 of the second telecommunications carrier. Therefore, the radio waves from the base station (BS-2) 902 of the second telecommunications carrier are distributed (relayed) from facility 1-2 102 to facility 20 via the master unit (MU-2) 2012. Furthermore, the distributed antenna system 2002 is connected to the repeater (HU-n) 202 of facility 20. n , 1st-n facility 10 n The main unit (MU-n) 201 n , 2nd-n communication channel Tb n The configuration uses optical fiber for connection. Facility 1-n 10 n The main unit (MU-n) 201 n This refers to the base station (BS-n) 90 of the Nth telecommunications carrier. n It is connected to the first-n facility 10. n From the main unit (MU-n) 201 n via the Nth telecommunications carrier's base station (BS-n) 90 n The radio waves are distributed (relayed) to facility 20.

[0073] In other words, the distributed antenna system 2002 according to this embodiment consists of multiple repeaters (HU-1) 2021 to (HU-n) 202 of a second facility 20 where a base station (BS) 90 is not installed. n Each of these has different base stations (BS-1)901~(BS-n)90 corresponding to each telecommunications carrier located around the second facility 20. nEach of the following is installed in multiple first facilities 101-10 n Each master unit (MU-1) 2011~(MU-n) 201 n However, the connection is made via optical fiber.

[0074] With this configuration, even in the second facility 20 where base stations (BS) 90 are not installed, multiple communication areas NA1 to NA corresponding to the frequency bands provided by each telecommunications carrier can be established without installing multiple new base stations (BS) 90 for each telecommunications carrier. n This can be constructed within the facility. Therefore, stable communication quality can be provided to each telecommunications carrier's communication terminals at the second facility 20 where base station (BS) 90 is not installed.

[0075] The technology disclosed herein is not limited to the embodiments and modifications described above, and various modifications are possible without departing from its essence. Furthermore, each configuration shown in the embodiments and modifications can be combined in any way. In other words, although the technology disclosed herein is described in accordance with the embodiments, it is understood that it is not limited to those embodiments or structures. The technology disclosed herein also encompasses various modifications and variations within the equivalent scope. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and conceptual range of the technology disclosed herein. [Explanation of symbols]

[0076] 100,200 distributed antenna system; 101 Master unit; 102,201 repeaters; 103,203 handset; Ta,Tb,Tc communication path; NA Communication Area

Claims

1. A distributed antenna system (200) that distributes radio waves from a base station (90) to expand the communication area (NA), One or more base stations (201) that receive the radio waves from the base station, One or more repeaters (202) that distribute the radio waves to the aforementioned communication area, The system includes one or more sub-units (203) connected to one or more antennas for providing the aforementioned communication area, The base station and the master unit are installed in the first facility (10), and the base station is connected to the master unit via the first communication channel (Ta). The repeater and the slave unit are installed in a second facility (20) which is different from the first facility and where the base station is not installed, and the repeater is connected to the slave unit via a third communication channel (Tc). A distributed antenna system in which the repeater of the second facility is configured to be connected to the master unit of the first facility via an optical transmission path which is a second communication path (Tb).

2. The distributed antenna system according to claim 1, wherein the optical transmission path is an optical fiber.

3. The distributed antenna system according to claim 1 or 2, wherein the master unit comprises a plurality of communication devices (2111) corresponding to each of a plurality of frequency bands, which is at least three in number.

4. The distributed antenna system according to claim 1 or 2, wherein the master unit and the repeater and / or slave unit each include an SFP module that satisfies the following conditions: optical reception sensitivity that falls within a predetermined reception power range corresponding to desired long-distance optical transmission, and optical output power that falls within a predetermined output power range corresponding to desired long-distance optical transmission.

5. A distributed antenna system (200) that distributes radio waves from a base station (90) to expand the communication area (NA), One or more base stations (201) that receive the radio waves from the base station, The system includes one or more sub-units (203) to which one or more antennas are connected for providing the aforementioned communication area, The base station and the master unit are installed in the first facility (10), and the base station is connected to the master unit via the first communication channel (Ta). The aforementioned slave unit is installed at a second facility (20) which is different from the first facility and where the base station is not installed. A distributed antenna system in which the slave unit of the second facility is configured to be connected to the master unit of the first facility via an optical transmission path which is a second communication path (Tb).

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