MIMO communication system based on cross-polarized leaky coaxial cable

Abstract

The present application relates to the technical field of mobile communications, and provides an MIMO communication system based on a cross-polarized leaky coaxial cable, applicable to coverage of 2G / 3G / 4G / 5G / 6G signals. By receiving signals of different standards from different operators, it is determined whether adjacent channel interference and intermodulation interference occur in the combination of the signals. The signals of different standards in the combination of the signals of different standards which produce interferences are respectively fed into different leaky coaxial cables, so that on one hand, adjacent channel interference between adjacent channel signals in a same leaky coaxial cable can be avoided, or intermodulation interference among different signals can be avoided, and the interferences between the signals are reduced, thereby improving the communication quality; and on the other hand, the radiation polarization directions of every two adjacent leaky coaxial cables are different, so that the coherence of leaky coaxial cable signals is reduced, thereby improving the communication quality.

Description

A cross-polarization leaky cable MIMO communication system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 6, 2023, with application number 202311140109.0 and application name “A Cross-Polarization Leaky Cable MIMO Communication System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of mobile communication technology, and in particular to a cross-polarization leaky cable MIMO communication system. Background Art

[0003] A leaky cable is a device that integrates signal transmission, emission, and reception functions, and has the dual functions of a coaxial cable and an antenna. It is mainly suitable for coverage in narrow and long areas such as tunnels, alleyways, and subways. When building a wireless communication system based on leaky cables, due to the large number of operator frequency bands, the leaky cable communication system needs to centrally transmit signals from multiple frequency bands. When multiple operator frequency bands are fed into the same leaky cable, interference is likely to occur. In the actual network transmission process, the transmitted signal is easily interfered with by asynchronous or multipath fading transmission channels, resulting in co-channel interference or adjacent-channel interference. These interferences can easily cause signal instability, noise, and intermittent noise in the entire mobile communication network during transmission. In addition, the signal source devices of each operator are independent of each other, and there is no coordinated communication control step, which is not conducive to reducing co-channel or adjacent-channel interference, and it is difficult to further improve the capacity of the MIMO system.

[0004] Currently, implementing a MIMO system using multiple leaky cables with the same polarization requires high spacing between them. If the spacing between adjacent leaky cables does not meet the required spatial isolation, MIMO capacity will be severely impacted. However, within the limited installation space of rail transit, a variety of cables and equipment, such as subway-specific leaky cables, police leaky cables, and optical cable racks, must be installed. To prevent interference, cables for different wireless communication systems also need to be installed at a certain distance from each other. This results in limited installation space for leaky cables, while also requiring sufficient spacing, making it difficult to deploy MIMO systems larger than 2×2.

[0005] Summary of the Invention

[0006] In view of this, the purpose of the present application is to provide a cross-polarization leaky cable MIMO communication system.

[0007] In the first aspect, an embodiment of the present application provides a cross-polarization leaky cable MIMO communication system, comprising: multiple RRU (remote radio frequency unit) devices, multiple POIs (multi-system access combining platforms) and multiple leaky cables arranged side by side, and the radiation polarization directions of the two adjacent leaky cables are different; the POI signals are connected to the leaky cables, and each POI is connected to one leaky cable; the RRU devices are connected to the POI signals, wherein the RRU device signals of the 5G / 6G standard are connected to all the POIs; the RRU device signals of the 2G / 3G / 4G standard in which there is adjacent channel interference or intermodulation interference are connected to different POIs.

[0008] This embodiment reduces the signal interference between different leaky cables and improves the communication quality by setting adjacent leaky cables as leaky cables with different radiation polarization directions, connecting POIs to the leaky cables, connecting RRU devices to the POI signals, and connecting the RRU device signals of the 5G / 6G standard to all the POIs; the RRU device signals of the 2G / 3G / 4G standard where there is adjacent frequency interference or intermodulation interference are connected to different POIs.

[0009] In some embodiments, a control unit is further included, connected between the RRU device and the POI, and the control unit is used to receive signals of different standards and different frequency bands from different operators of the multiple RRU devices, combine the signals of different frequency bands of 2G / 3G / 4G standards in pairs to form signal pairs, determine whether the signal pairs will cause adjacent channel interference or intermodulation interference, and feed the signals of different frequency bands of 5G / 6G standards into all POIs, and feed the signals of different frequency bands of 2G / 3G / 4G standards in the signal pairs that cause interference into different POIs respectively.

[0010] Furthermore, by setting up a control unit and using the control unit to connect the RRU equipment and POI, signals of different operators, different standards, and different frequency bands sent by the RRU side are received, and signals of different frequency bands of the 5G / 6G standard are fed into all POIs. Signals of different frequency bands of the 2G / 3G / 4G standard are combined in pairs to form signal pairs, and it is determined whether the signal pairs will cause adjacent channel interference or intermodulation interference. The signals of different frequency bands of the 2G / 3G / 4G standard in the signal pairs that cause interference are fed into different POIs respectively, so as to reduce the signal interference between leaky cables.

[0011] In some embodiments, the control unit also includes an adjacent frequency interference judgment module, which is used to obtain the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal; based on the first frequency upper limit being less than the second frequency upper limit, and the difference between the second frequency lower limit and the first frequency upper limit being no more than 1MHz, or based on the first frequency upper limit being greater than the second frequency upper limit, and the difference between the first frequency lower limit and the second frequency upper limit being no more than 1MHz, it is determined that the signal pair will cause adjacent frequency interference.

[0012] Furthermore, by comparing the upper and lower frequency limits of the two signals in the signal pair, it is determined whether the two signal pairs generate adjacent frequency interference, so that the two signals that generate adjacent frequency interference can be fed into different leaky cables with a larger distance between them to further reduce interference.

[0013] In some embodiments, the control unit further includes an intermodulation interference judgment module, which is used to obtain a first frequency upper limit and a first frequency lower limit of the frequency band of the first signal in the signal pair, and a second frequency upper limit and a second frequency lower limit of the frequency band of the second signal; according to the intermodulation interference formula |m1F1±m2F2±···±m n F n |Calculate the frequency at which the signal pair generates intermodulation interference, where m1±m2···±m n +n≤9,m n ≤8,n≤9,m n and n are positive integers, F n Any one of the first frequency upper limit, the first frequency lower limit, the second frequency upper limit and the second frequency lower limit; according to the above-mentioned frequency generating intermodulation interference falling within the frequency band of signals of different standards and different frequency bands from different operators, it is determined that the signal pair will generate intermodulation interference.

[0014] Furthermore, by obtaining the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal, and combining the intermodulation interference formula to calculate the frequency that causes intermodulation interference to the first signal and the second signal, if the frequency that causes intermodulation interference falls within the frequency band of signals of different standards and different frequency bands from different operators, it is determined that the signal pair will cause intermodulation interference, so that the two signals that will cause intermodulation interference will be fed into different leaky cables with a large distance between them to further reduce interference.

[0015] In some embodiments, the control unit and the multiple POIs are integrated into one unit; or, the multiple POIs are integrated into one POI unit, and the control unit is connected between the POI unit and the multiple RRU devices.

[0016] Furthermore, by integrating the control unit and the multiple POIs into one unit, or integrating multiple POIs into one POI unit, and connecting the control unit between the POI unit and the multiple RRU devices, a simplified structure is achieved, which facilitates the installation and maintenance of the equipment.

[0017] In some embodiments, the polarization direction of the leaky cable is vertical polarization, horizontal polarization, +45° polarization, or -45° polarization.

[0018] Furthermore, by setting different polarization directions of the leaky cables, the minimum installation distance between the cables is reduced, thereby saving the space required for the installation of the leaky cables. More leaky cables can also be arranged, increasing the number of user access and improving the quality of communication.

[0019] In some embodiments, the RRU device of 2G / 3G / 4G standard is signal-connected to two POIs at most.

[0020] Furthermore, by limiting the number of POIs to which the RRU device of 2G / 3G / 4G standard signals are connected, signal interference is reduced, thereby improving communication quality.

[0021] In some embodiments, the radiation polarization directions of the plurality of leaky cables are arranged alternately in a horizontal polarization and a vertical polarization manner.

[0022] Furthermore, by arranging the radiation polarization directions of the leaky cables alternately in horizontal and vertical polarization, the minimum allowable distance between the leaky cables is reduced, so that more leaky cables can be deployed, the number of user access is increased, and the communication quality is improved.

[0023] In some embodiments, signals of different frequency bands of 2G / 3G / 4G standards are combined in pairs to form signal pairs, and the two signals in the signal pairs that generate adjacent channel interference or intermodulation interference are fed into different leaky cables with the same polarization mode through different POIs.

[0024] Furthermore, signals of different frequency bands of the 2G / 3G / 4G standards are combined in pairs to form signal pairs, and the two signals in the signal pair that generate interference are fed into different leaky cables with the same polarization mode through different POIs, avoiding interference between signals and improving communication quality.

[0025] On the second aspect, an embodiment of the present application provides a cross-polarized leaky cable MIMO communication system, including an RRU device, a POI and a plurality of leaky cables arranged side by side, the radiation polarization directions of the adjacent leaky cables are different, and the POI signal is connected to the leaky cable; it also includes: a signal receiving module, connected to the RRU device, for receiving signals of different standards and different frequency bands from different operators of the RRU device; an interference combination screening module, connected to the signal receiving module, for combining signals of different frequency bands of 2G / 3G / 4G standards in pairs to form a signal pair, and judging whether the signal pair will generate adjacent frequency interference or intermodulation interference; a leaky cable feeding control module, connected to the interference combination screening module, the signal receiving module and the POI, for feeding signals of different frequency bands of 5G / 6G standards into all leaky cables through the POI, and feeding the signals of different frequency bands of the 2G, 3G, and 4G standards in the signal pair that generates interference into different leaky cables through the POI.

[0026] Furthermore, the system enables the configuration and control of links from different operators' RRUs to POI input ports, preventing adjacent frequency signals and interfering signals from being fed into the same leaky cable, reducing signal interference and improving communication quality. Furthermore, the radiation polarization directions of adjacent leaky cables differ, reducing the required distance between them and facilitating installation. This allows for the deployment of more leaky cables, increasing user access and improving communication quality.

[0027] On the third aspect, an embodiment of the present application provides a cross-polarization leaky cable MIMO communication system, including RRU devices of different standards and frequency bands of China Unicom, China Mobile, and China Telecom, a first POI, a second POI, a third POI, a fourth POI, and four leaky cables arranged side by side, the radiation polarization directions of the two adjacent leaky cables are different, and each POI device is separately connected to a leaky cable; all 5G / 6G RRU device signals in the RRU device are connected to all POI devices, and the 2G / 3G / 4G RRU device signals whose signals in the RRU device generate adjacent channel interference or intermodulation interference are connected to different POI devices.

[0028] Furthermore, by setting up RRU equipment of different standards and frequency bands for each operator, four leaky cables are arranged side by side, and the radiation polarization directions of the two adjacent leaky cables are different, each POI device is connected to a leaky cable separately, all 5G / 6G RRU device signals are connected to all POI devices, and the 2G / 3G / 4G RRU device signals that generate adjacent frequency interference or intermodulation interference in the RRU devices are connected to different POI devices, thereby reducing signal interference and improving communication quality.

[0029] The beneficial effects that this application can achieve.

[0030] A cross-polarization leaky cable MIMO communication system provided in the present application can be applicable to the coverage of 2G / 3G / 4G / 5G / 6G signals. By receiving signals of different standards from different operators and processing 2G / 3G / 4G and / 5G / 6G signals separately, the signals of different frequency bands of the 5G / 6G standards are fed into all leaky cables, thereby ensuring the power of the 5G / 6G signals and improving the network coverage and download rate of the 5G / 6G signals; the signals of different frequency bands of the 2G / 3G / 4G standards are combined in pairs to form signal pairs, and it is determined whether the signal pairs will generate adjacent-frequency interference or intermodulation interference. The signals of the different standards in the combination of the signals of the different standards that generate interference are respectively fed into different leaky cables. On the one hand, adjacent-frequency interference between adjacent-frequency signals in the same leaky cable can be avoided, or intermodulation interference between different signals can be avoided, thereby reducing signal interference and improving communication quality. On the other hand, the radiation polarization directions of the two adjacent leaky cables are different, which reduces the minimum installation distance between the leaky cables, thereby saving the space required for the installation of the leaky cables, and allowing more leaky cables to be arranged, increasing the number of user access and improving the quality of communication.

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 shows a schematic diagram of a 2G / 3G / 4G leaky cable laying scheme for a subway tunnel according to the present application;

[0033] FIG2 shows a schematic diagram of the structural principle of a cross-polarization leaky cable MIMO communication system of the present application;

[0034] FIG3 shows a schematic diagram of the structural principle of a cross-polarization leaky cable MIMO communication system with a control unit of the present application;

[0035] FIG4 shows a schematic diagram of the structural principle of a control unit of a cross-polarization leaky cable MIMO communication system of the present application;

[0036] FIG5 shows a flow chart of a cross-polarization leaky cable MIMO communication control method of the present application;

[0037] FIG6 shows a second schematic diagram of the structural principle of a cross-polarization leaky cable MIMO communication system of the present application;

[0038] FIG7 shows a second schematic diagram of the structural principle of a control unit of a cross-polarization leaky cable MIMO communication system of the present application.

[0039] Among them: 1-communication room, 2-coupler, 3-power splitter, 4-leaky cable, 5-source equipment, 6-POI (multi-system access combining platform), 7-China Telecom CDMA RRU, 8-China Mobile FDD-LTE1.8 RRU, 9-China Unicom FDD-LTE1.8 RRU, 10-China Telecom FDD-LTE2.1 RRU, 11-China Mobile TD(E) RRU, 12-China Mobile NR2.6 RRU, 13-China Telecom and China Unicom NR3.5 RRU, 14-first POI, 15-second POI, 16-third POI, 17-fourth POI, 18-first vertical polarization leaky cable, 19-first horizontal polarization leaky cable, 20-second vertical polarization leaky cable, 21-second horizontal polarization leaky cable, 22-signal receiving module, 23-interference combination screening module, 24-leaky cable feeding control module, 25-control unit, 26-adjacent channel interference judgment module, 27-intermodulation interference judgment module. DETAILED DESCRIPTION

[0040] The term "comprising" in the specification, claims, and drawings of this application is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional unrecited elements or method steps. "Comprising" is a technical term used in claim language to mean that an element is present, but other elements may be added and still form a structure or method within the scope of the claim.

[0041] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance. The term "about" in this application is meant to include slight variations (up to + / - 10%) from the value.

[0042] The present application has found that when constructing a wireless communication system based on leaky cables, due to the large number of operator frequency bands, when the leaky cable communication system needs to centrally transmit multiple frequency band signals, interference is likely to occur after multiple operator frequency bands are fed into the same leaky cable. In the actual network transmission process, the transmitted signal is easily interfered with by the asynchronous or multipath fading transmission channel, forming co-channel interference or adjacent-channel interference. These interferences can easily cause the entire mobile communication network to generate signal instability, noise, and murmurs during the transmission process. In addition, the signal source devices of each operator are independent of each other, and there is no coordinated communication control step, which is not conducive to reducing co-channel or adjacent-channel interference, and it is difficult to further improve the capacity of the MIMO system.

[0043] At the same time, using multiple leaky cables with the same polarization to implement a MIMO system requires high spacing between them. If the spacing between adjacent leaky cables does not meet the spatial isolation requirements, the MIMO capacity will be severely affected. However, within the limited installation space of rail transit, a variety of cables and equipment, such as subway-specific leaky cables, police leaky cables, and optical cable racks, must be installed. To avoid interference, cables of different wireless communication systems also need to be installed at a certain distance from each other. This results in limited installation space for leaky cables, and the required spacing, making it difficult to deploy MIMO systems with a number greater than 2×2.

[0044] In view of this, an embodiment of the present application provides a cross-polarization leaky cable MIMO communication system control method for reducing interference, including the steps of: receiving signals of different standards and different frequency bands from different operators; combining signals of different frequency bands of 2G / 3G / 4G standards in pairs to form signal pairs, and determining whether the signal pairs will cause adjacent channel interference or intermodulation interference; feeding signals of different frequency bands of 5G / 6G standards into all leaky cables, and feeding signals of different frequency bands of 2G / 3G / 4G standards in the signal pairs that generate interference into different leaky cables respectively, and the radiation polarization directions of two adjacent leaky cables are different.

[0045] In other embodiments of the present application, a cross-polarization leaky cable MIMO communication system is also provided, including: multiple RRU devices, multiple POIs and multiple leaky cables arranged side by side, and the radiation polarization directions of two adjacent leaky cables are different; POI signals are connected to the leaky cables, and each POI is connected to a leaky cable; RRU devices are connected to POI signals, wherein the RRU device signals of 5G / 6G standards are connected to all POIs; RRU device signals in 2G / 3G / 4G standards where there is adjacent channel interference or intermodulation interference are connected to different POIs.

[0046] A cross-polarization leaky cable MIMO communication system control method and a cross-polarization leaky cable MIMO communication system for reducing interference provided in the embodiments of the present application can be applied to the coverage of 2G / 3G / 4G / 5G / 6G signals. By receiving signals of different standards from different operators and processing 2G / 3G / 4G and 5G / 6G signals separately, signals of different frequency bands of the 5G / 6G standards are fed into all leaky cables, thereby ensuring the power of the 5G / 6G signals and improving the network coverage and download rate of the 5G / 6G signals; the signals of different frequency bands of the 2G / 3G / 4G standards are combined in pairs to form signal pairs, and it is determined whether the signal pairs will generate adjacent-frequency interference or intermodulation interference. The signals of different standards in the combination of signals of different standards that generate interference are fed into different leaky cables respectively. On the one hand, adjacent-frequency interference between adjacent-frequency signals in the same leaky cable can be avoided, or intermodulation interference between different signals can be avoided, thereby reducing signal interference and improving communication quality. On the other hand, the radiation polarization directions of two adjacent leaky cables are different, which reduces the minimum installation distance between the cables, thereby saving the space required for the installation of the leaky cables. More leaky cables can also be arranged, increasing the number of user access and improving the quality of communication.

[0047] In other embodiments of the present application, a cross-polarized leaky cable MIMO communication system is also provided, including an RRU device, a POI and multiple leaky cables arranged side by side, the radiation polarization directions of two adjacent leaky cables are different, and the POI signals are connected to the leaky cables; it also includes: a signal receiving module, connected to the RRU device, for receiving signals of different standards and different frequency bands from different operators of the RRU device; an interference combination screening module, connected to the signal receiving module, for combining signals of different frequency bands of 2G / 3G / 4G standards in pairs to form signal pairs, and judging whether the signal pairs will generate adjacent frequency interference or intermodulation interference; a leaky cable feeding control module, connected to the interference combination screening module, the signal receiving module and the POI, for feeding signals of different frequency bands of 5G / 6G standards into all leaky cables through the POI, and feeding signals of different frequency bands of 2G, 3G and 4G standards in the signal pairs that generate interference into different leaky cables through the POI.

[0048] In the above embodiment, a signal receiving module, an interference combination screening module, and a leaky cable feeding control module are provided to connect RRU devices of different operators to receive signals of different standards from different operators, and feed signals of different frequency bands of 5G / 6G standards into all leaky cables. It is determined whether the combination of signals of different frequency bands of 2G / 3G / 4G standards will generate adjacent channel interference and intermodulation interference, and the signals of different frequency bands of 2G / 3G / 4G standards that generate interference are fed into different leaky cables through POI respectively, so as to realize the setting and control of the link from RRU devices of different operators to POI input ports, avoid adjacent frequency signals and interference-generating signals from being fed into the same leaky cable, reduce signal interference, improve communication quality, and at the same time ensure the power of 5G / 6G signals, which can improve the network coverage and download rate of 5G / 6G signals.

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0051] Example 1

[0052] Mobile communications have continued to develop at a rate of one generation of technology every ten years, having gone through the development of 1G, 2G, 3G, 4G, and 5G. The next generation, 6G, is currently under development. Each generational leap and each technological advancement has greatly promoted industrial upgrading and economic and social development. Leaky cables are transmission cables that integrate signal transmission, emission, and reception, serving as both coaxial cables and antennas. They are primarily suitable for coverage in narrow and long areas such as tunnels, alleyways, and subways. Currently, leaky cables are generally deployed for network coverage in narrow, confined indoor environments. For example, subways are the preferred public transportation in large cities. With complex environments and high traffic volumes, they are typical indoor data hotspots for operators and a key scenario for user word-of-mouth evaluation and service experience. Therefore, subways have become a key scenario for communication network coverage.The leaky cable communication system needs to centrally transmit signals from multiple frequency bands, such as China Mobile's GSM900MHz (uplink 890-909MHz, downlink 935-954MHz), EGSM900MHz (uplink 885-890MHz, downlink 930-935MHz), GSM1800MHz (uplink 1710-1735MHz, downlink 1805-1830MHz) on the 2G network, China Unicom's GSM900MHz (uplink 909-915MHz, downlink 954-960MHz), GSM1800MHz (uplink 1735-1755MHz, downlink 1830-1850MHz), China Telecom's CDMA800MHz (uplink 825-835MHz, downlink 870-880MHz); China Mobile's TD-SCDMA on the 3G network 1880-1900MHz / 2010-2025MHz, China Unicom's WCDMA: 2100MHz (uplink 1940-1965MHz, downlink 2130-2155MHz), China Telecom's 3G CDMA (uplink 1920-1940MHz, downlink 2110-2130MHz); China Mobile's 4G network FDD-LTE 900MHz (uplink 892-904MHz, downlink 937-949MHz), TD-LTE 1880-1900MHz / 2320-2370MHz / 2575-2675MHz, China Unicom's FDD-LTE (uplink 1745-1765MHz, downlink 1840-1860MHz), TD-LTE 2300-2320MHz / 2555-2575MHz, China Telecom's FDD-LTE (uplink 1765-1780MHz, downlink 1860-1875MHz), TD-LTE 2370-2390MHz / 2635-2655MHz; China Mobile's 5G network is 2.6GHz (2515MHz-2675MHz) / 4.9GHz (4800MHz-4900MHz), China Unicom's 3.5GHz (3500-3600MHz), and China Telecom's 3.5GHz (3400-3500MHz); the frequency bands of 6G networks can be 7025-7125MHz, 6425-7025MHz, 5925-7125MHz, and 10000-10500MHz. Due to the large number of operator frequency bands, it is inevitable that adjacent frequencies will coexist in the same geographical area. When multiple operator frequency bands are fed into the same leaky cable, interference is likely to occur. For example, China Unicom's 4G frequency band is 1840-1860MHz, China Telecom's 4G frequency band is 1860-1875MHz, and China Mobile's 4G frequency band is 1880-1900MHz. These frequency bands are close to each other, and feeding them into the same leaky cable at the same time will cause serious interference between adjacent frequencies.For example, China Mobile's TD-LTE and the TD-SCDMA of the already widely deployed 3G network coexist in adjacent frequencies in the same geographical area, which will inevitably cause a certain degree of interference. This interference can easily lead to signal instability, noise, and interference in the transmission process of the entire mobile communication network.

[0053] For example, as shown in FIG1 , a schematic diagram of a 2G / 3G / 4G leaky cable installation scheme for a subway tunnel shows that a communication room 1 is provided with signal source devices 5 (e.g., RRU remote radio frequency modules) of different standards and frequency bands from various operators, such as China Telecom, China Unicom, and China Mobile. The signal source signals from each signal source device 5 are transmitted through a POI 6 (multi-system access combining platform) and then through a coupler 2 (coupler 2 is provided to facilitate signal transmission to the station hall or platform. One signal path can be transmitted to the station hall or platform through the coupler to achieve coverage of the station hall or platform) and a power splitter 3, or are transmitted only through the power splitter 3 to the leaky cable 4, which is then used to cover the communication in the tunnel section. The signal source devices 5 of each operator are independent of each other and lack coordinated communication control steps, which is not conducive to reducing co-channel or adjacent-channel interference and makes it difficult to further improve the capacity of the MIMO system.

[0054] Furthermore, Multiple Input Multiple Output (MIMO) is a crucial technology in 5G / 6G communications, significantly increasing channel capacity. Multiple antennas are used at both the transmitter and receiver, creating a multi-channel transmission system. Figure 1 shows a 2×2 MIMO system. Currently, multiple leaky cables are used to implement MIMO. However, because these cables use the same polarization, if the spacing between them does not meet the required spatial isolation, MIMO capacity will be severely impacted.

[0055] In view of this, the present application provides a leaky cable MIMO communication system that reduces interference, as shown in Figure 2, including RRUs (Remote Radio Unite) of different frequency bands of different operators. The RRUs and BBUs (Building Baseband Unite) transmit signals through optical fibers, and the BBUs are generally placed in the communication room. Figure 2 includes RRU units of various operators, including China Telecom CDMA RRU 7, China Mobile FDD-LTE1.8 RRU 8, China Unicom FDD-LTE1.8 RRU 9, China Telecom FDD-LTE2.1 RRU 10, China Mobile TD(E)RRU 11 (i.e., China Mobile TD-LTE E-band RRU), China Mobile NR2.6 RRU 12, and China Telecom and China Unicom NR3.5 RRU 13, which meet the network coverage of 2G / 3G / 4G / 5G. Since 6G has not yet been officially put into use, it is not schematically drawn in Figure 2. China Telecom's CDMA RRU 7 uses the 800 MHz frequency band, with a frequency range of 825-835 MHz / 870-880 MHz. China Mobile's FDD-LTE1.8 RRU 8 uses the 1.8 GHz frequency band, with a frequency range of 1710-1735 MHz / 1805-1830 MHz. China Unicom's FDD-LTE1.8 RRU 9 uses the 1.8 GHz frequency band, with a frequency range of 1735-1765 MHz / 1830-1860 MHz. China Telecom's FDD-LTE2.1 RRU 10 uses the 2.1 GHz frequency band, with a frequency range of 1920-1940 MHz / 2110-2130 MHz. China Mobile's TD(E) (i.e., China Mobile TD-LTE) uses the E band, and China Mobile's TD(E) RRU 11 uses the 2.3 GHz frequency band, with a frequency range of 2320-2370 MHz. China Mobile's NR2.6 RRU 12 uses the 2.6 GHz frequency band, which ranges from 2515 MHz to 2675 MHz. China Telecom and China Unicom's NR3.5 RRU 13 uses the 3.5 GHz frequency band, which ranges from 3400 MHz to 3500 MHz and 3500 MHz to 3600 MHz.

[0056] The frequency range of China Telecom CDMA800 is 825-835MHz (uplink) / 870-880MHz (downlink). The third-order intermodulation signals of its second harmonic (1650-1670MHz / 1740-1760MHz) and China Telecom FDD-LTE2.1 (frequency range is 1920-1940MHz / 2110-2130MHz) fall into the 3.5GHz frequency band, which may cause unintended intermodulation interference to China Telecom and China Unicom NR3.5. To reduce interference, China Telecom CDMA RRU 7 and China Telecom FDD-LTE2.1 RRU 10 are separately connected to different POIs. For example, China Telecom CDMA RRU 7 accesses the first POI 14 and the fourth POI 17, and China Telecom FDD-LTE2.1 RRU 10 accesses the second POI 15 and the third POI 16. China Mobile's FDD-LTE1.8 (1710-1735MHz / 1805-1830MHz) and China Unicom's FDD-LTE1.8 (1735-1765MHz / 1830-1860MHz) frequencies are closely spaced. To minimize interference, China Mobile's FDD-LTE1.8 RRU 8 and China Unicom's FDD-LTE1.8 RRU 9 are connected to different POIs. For example, China Mobile's FDD-LTE1.8 RRU 8 connects to POI 14 and POI 16, while China Unicom's FDD-LTE1.8 RRU 9 connects to POI 15 and POI 17. Furthermore, to minimize interference, China Telecom's FDD-LTE2.1 RRU 10, China Mobile's FDD-LTE1.8 RRU 8, and China Unicom's FDD-LTE1.8 RRU 9 are also designed to avoid co-location.

[0057] A cross-polarization leaky cable MIMO communication system provided in the present application includes RRU devices of different standards and frequency bands of China Unicom, China Mobile and China Telecom, a first POI, a second POI, a third POI, a fourth POI and four leaky cables arranged side by side, the radiation polarization directions of two adjacent leaky cables are different, and each POI device is connected to a leaky cable separately; all 5G / 6G RRU device signals in the RRU device are connected to all POI devices, and the 2G / 3G / 4G RRU device signals whose signals in the RRU device generate adjacent channel interference or intermodulation interference are connected to different POI devices.

[0058] The cross-polarization leaky cable MIMO communication system in this embodiment improves the connection between RRUs and POI devices. In this embodiment, with four cross-polarization leaky cables, each 2G / 3G / 4G RRU device from different operators can only connect to two POI devices at most, while each 5G / 6G RRU device from different operators connects to all POI devices. In other words, each POI device connects to all 5G / 6G RRU devices from different operators. As shown in Figure 2, in this embodiment, the China Telecom CDMA RRU 7 is connected to the first POI 14 and the fourth POI 17, so that the CDMA800 standard signal can be fed into the first vertical polarization leaky cable 18 or the second horizontal polarization leaky cable 21; the China Mobile FDD-LTE1.8 RRU 8 is connected to the first POI 14 and the third POI 16, so that the China Mobile FDD-LTE1.8 standard signal can be fed into the first vertical polarization leaky cable 18 or the second vertical polarization leaky cable 20; the China Unicom FDD-LTE1.8 RRU 9 is connected to the second POI 15 and the fourth POI 17, so that the China Unicom FDD-LTE1.8 standard signal can be fed into the first horizontal polarization leaky cable 19 or the second horizontal polarization leaky cable 21; the China Telecom FDD-LTE2.1 RRU 10 is connected to the second POI 15 and the third POI 16, so that the telecom FDD-LTE2.1 standard signal can be fed into the first horizontal polarization leaky cable 19 or the second vertical polarization leaky cable 20; the mobile TD(E) RRU 11 is connected to the third POI 16 and the fourth POI 17, so that the mobile TD(E) standard signal can be fed into the second vertical polarization leaky cable 20 or the second horizontal polarization leaky cable 21; the mobile NR2.6 RRU 12 is connected to the first POI 14, the second POI 15, the third POI 16, and the fourth POI 17, so that the mobile NR2.6 standard signal can be fed into the first vertical polarization leaky cable 18, the first horizontal polarization leaky cable 19, the second vertical polarization leaky cable 20 or the second horizontal polarization leaky cable 21; the telecom and Unicom NR3.5 RRU 13 is connected to the first POI 14, the second POI 15, the third POI 16, and the fourth POI 17 Thus, the China Telecom and China Unicom NR3.5 standard signal can be fed into the first vertical polarization leaky cable 18, the first horizontal polarization leaky cable 19, the second vertical polarization leaky cable 20 or the second horizontal polarization leaky cable 21.

[0059] As shown in Table 1 below, in Figure 2, the first POI 14 receives signals from China Telecom's CDMA RRU 7, China Mobile's FDD-LTE1.8 RRU 8, China Mobile's NR2.6 RRU 12, and China Telecom's NR3.5 RRU 13. The second POI 15 receives signals from China Unicom's FDD-LTE1.8 RRU 9, China Telecom's FDD-LTE2.1 RRU 10, China Mobile's NR2.6 RRU 12, and China Telecom's NR3.5 RRU 13. The third POI 16 receives signals from China Mobile's FDD-LTE1.8 RRU 8, China Telecom's FDD-LTE2.1 RRU, China Mobile's TD(E) RRU 11, China Mobile's NR2.6 RRU 12, and China Telecom's NR3.5 RRU 13. The fourth POI 17 receives signals from the China Telecom CDMA RRU 7, the China Unicom FDD-LTE1.8 RRU 9, the China Mobile TD(E) RRU 11, the China Mobile NR2.6 RRU 12, and the China Telecom and China Unicom NR3.5 RRU 13.

[0060] Table 1: Four-cable distribution scheme connection table

[0061] In this embodiment, each leaky cable is connected to a separate POI. As shown in Figure 2, four leaky cables correspond to four POIs, namely, first POI 14, second POI 15, third POI 16, and fourth POI 17. As shown in Figure 2, first POI 14 is connected to a first vertically polarized leaky cable 18, second POI 15 is connected to a first horizontally polarized leaky cable 19, third POI 16 is connected to a second vertically polarized leaky cable 20, and fourth POI 17 is connected to a second horizontally polarized leaky cable 21.

[0062] In Figure 2, the standard signals of different frequency bands of RRUs of different operators are combined through a POI and fed into a leaky cable respectively. For example, the signal is combined after the first POI14 and fed into the first vertical polarization leaky cable 18, the signal is combined after the second POI15 and fed into the first horizontal polarization leaky cable 19, the signal is combined after the third POI16 and fed into the second vertical polarization leaky cable 20, and the signal is combined after the fourth POI17 and fed into the second horizontal polarization leaky cable 21.

[0063] As shown in Figure 2, multiple leaky cables arranged side by side in a leaky cable MIMO system are cross-polarized, meaning that the radiation polarization directions of adjacent leaky cables are different. For example, in this embodiment, four leaky cables are used to form a 4×4 MIMO system with 4 receive and 4 transmit signals. The first cable is vertically polarized, the second is horizontally polarized, the third is vertically polarized, and the fourth is horizontally polarized. As shown in Figure 2, they are first vertically polarized leaky cable 18, first horizontally polarized leaky cable 19, second vertically polarized leaky cable 20, and second horizontally polarized leaky cable 21, respectively.

[0064] In this embodiment, as shown in Figure 2, because there are 4 leaky cables, if each RRU device needs dual-channel output, it is inevitable that adjacent frequency signals must be in the same leaky cable. However, in order to reduce interference, at most two adjacent frequency signals can be in one leaky cable. The 2G / 3G / 4G signals of different operators are separated and fed into different leaky cables after being combined with the 5G / 6G signals through POI. The same leaky cable can only be fed into the adjacent frequency bands of two operators at most. This can reduce the adjacent frequency interference between adjacent frequency signals in the same leaky cable. For example, China Mobile FDD-LTE1.8 (1710-1735MHz / 1805-1830MHz) and China Unicom FDD-LTE1.8 (1735-1765MHz / 1830-1860MHz), these two frequency bands are close to each other, and feeding the same leaky cable at the same time causes serious adjacent frequency interference. Therefore, it is necessary to combine them with the 5G / 6G signals and feed them into different leaky cables. When there are four leaky cables and 4G is a single-channel signal, the mobile FDD-LTE1.8 and 5G / 6G frequency bands are combined through the POI and fed into the first vertically polarized leaky cable 18, while the China Unicom FDD-LTE1.8 and 5G / 6G frequency bands are combined through the POI and fed into the second horizontally polarized leaky cable 19. When the 4G signal is a dual-channel signal, the mobile FDD-LTE1.8 and 5G / 6G frequency bands are combined through the first POI 14 and the third POI 16, respectively, and fed into the first vertically polarized leaky cable 18 and the second vertically polarized leaky cable 20. The China Unicom FDD-LTE1.8 and 5G / 6G frequency bands are combined through the second POI 15 and the fourth POI 17, respectively, and fed into the first horizontally polarized leaky cable 19 and the second horizontally polarized leaky cable 21.

[0065] In other embodiments, the number of POI devices and the number of leaky cables can be adjusted based on the conditions of the deployment scenario, for example, 3 leaky cables, 5 leaky cables, 6 leaky cables, 7 leaky cables, 8 leaky cables, 9 leaky cables, 10 leaky cables, etc. Generally, in a subway environment, in addition to communication leaky cables, the limited installation space of rail transit also requires the installation of various cables and equipment such as subway-specific leaky cables, police leaky cables, and optical cable racks. In order to avoid interference, cables of different wireless communication systems also need to be installed at a certain distance. In the tunnel inventory scenario, the number of leaky cables can be adjusted based on the space allowed by the deployment scenario and the actual needs of the communication network.

[0066] Furthermore, the polarization direction of the leaky cable is not limited to vertical or horizontal polarization. The direction of the electric field radiated from the slot of the leaky cable, i.e., the polarization direction, is perpendicular to the wide side of the slot. In other embodiments, the polarization direction of the leaky cable can have other design combinations, such as +45° polarization, -45° polarization, etc., as long as the radiation polarization directions of two adjacent leaky cables are different.

[0067] In some embodiments, four leaky cables are used, wherein the first one is vertically polarized, the second one is horizontally polarized, the third one is +45° polarized, and the fourth one is -45° polarized.

[0068] In some implementation examples, six leaky cables are used, wherein the first one is vertically polarized, the second one is horizontally polarized, the third one is +45° polarized, the fourth one is -45° polarized, the fifth one is vertically polarized, and the sixth one is horizontally polarized.

[0069] In some implementation examples, the radiation polarization directions of the multiple leaky cables are arranged alternately in a horizontal polarization and vertical polarization manner. Similarly, six leaky cables are used, of which the first is vertically polarized, the second is horizontally polarized, the third is vertically polarized, the fourth is horizontally polarized, the fifth is vertically polarized, and the sixth is horizontally polarized.

[0070] According to the adjustment of the number of POI devices and the number of leaky cables, a cross-polarization leaky cable MIMO communication system is provided in some embodiments of the present application, including: multiple RRU devices, multiple POIs, and multiple leaky cables arranged side by side, and the radiation polarization directions of two adjacent leaky cables are different. The POI signals are connected to the leaky cables, and each POI is connected to a leaky cable. The RRU devices are connected to the POI signals, wherein the RRU device signals of the 5G / 6G standard are connected to all POIs; the RRU device signals of the 2G / 3G / 4G standard RRU devices with adjacent channel interference or intermodulation interference are connected to different POIs.

[0071] In some embodiments of the present application, a cross-polarization leaky cable MIMO communication system is provided, as shown in FIG3 , which may further include a control unit connected between the RRU device and the POI. For example, in the structural principle shown in FIG3 , the China Telecom CDMA RRU 7, the China Mobile FDD-LTE1.8 RRU 8, the China Unicom FDD-LTE1.8 RRU 9, the China Telecom FDD-LTE2.1 RRU 10, the China Mobile TD(E) RRU 11 (i.e., the China Mobile TD-LTE E-band RRU), the China Mobile NR2.6 RRU 12, and the China Telecom Unicom NR3.5 RRU 13 are all connected to the control unit 25, and the control unit 25 is signal-connected to the first POI 14, the second POI 15, the third POI 16, and the fourth POI 17. The first POI 14 is connected to the first vertical polarization leaky cable 18, the second POI 15 is connected to the first horizontal polarization leaky cable 19, the third POI 16 is connected to the second vertical polarization leaky cable 20, and the fourth POI 17 is connected to the second horizontal polarization leaky cable 21. The control unit 25 is used to receive signals of different standards and different frequency bands from different operators of multiple RRU devices, combine the signals of different frequency bands of 2G / 3G / 4G standards in pairs to form signal pairs, determine whether the signal pairs will cause adjacent channel interference or intermodulation interference, and feed the signals of different frequency bands of 5G / 6G standards into all POIs, and feed the signals of different frequency bands of 2G / 3G / 4G standards in the signal pairs that cause interference into different POIs respectively.

[0072] Optionally, the two signals in the interfering signal pair can be fed into different leaky cables with spaced-apart settings (non-adjacent settings) through different POIs, so that the interfering signal pair is fed into different leaky cables with a larger spaced-apart distance, to further reduce interference.

[0073] Preferably, when the radiation polarization directions of multiple leaky cables are arranged alternately in horizontal and vertical polarization, the two signals in the interfering signal pair can be fed through different POIs into separate leaky cables with the same polarization and spaced apart. This design allows the interfering signal pair to be fed into separate leaky cables spaced far apart, further reducing interference.

[0074] As shown in Figure 4, the control unit 25 also includes an adjacent frequency interference judgment module 26, which is used to judge whether the signal pair will generate adjacent frequency interference. Specifically, the adjacent frequency interference judgment module 26 is used to obtain the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal; according to the first frequency upper limit being less than the second frequency upper limit, and the difference between the second frequency lower limit and the first frequency upper limit is not greater than 1MHz, or according to the first frequency upper limit being greater than the second frequency upper limit, and the difference between the first frequency lower limit and the second frequency upper limit is not greater than 1MHz, it is determined that the signal pair will generate adjacent frequency interference.

[0075] As shown in FIG4 , the control unit 25 further includes an intermodulation interference judgment module 27, which is used to judge whether the signal pair will generate intermodulation interference. Specifically, the intermodulation interference judgment module 27 is used to obtain the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal; according to the intermodulation interference formula |m1F1±m2F2±···±m n F n |Calculate the frequency of intermodulation interference between the signal pairs, where m1±m2···±m n +n≤9,m n ≤8,n≤9,m n and n is a positive integer, F n Any one of the first frequency upper limit, the first frequency lower limit, the second frequency upper limit and the second frequency lower limit; according to the above-mentioned frequency generating intermodulation interference falling within the frequency band of signals of different standards and different frequency bands from different operators, it is determined that the signal pair will generate intermodulation interference.

[0076] Of course, in other embodiments, it is also possible to predetermine the signal pairs that will generate intermodulation interference or adjacent frequency interference by artificial or independent processors outside the cross-polarization leaky cable MIMO communication system, and then determine the connection mode of the RRU equipment and POI corresponding to each signal pair. The method for specifically determining the signal pairs that generate intermodulation interference or adjacent frequency interference is the same as that of the above-mentioned control unit and will not be repeated here. In addition, in order to improve the integration of the system, in some embodiments, the control unit can be integrated into a unit with multiple POIs. In some embodiments, multiple POIs can be integrated into a POI unit, and the control unit is connected between the POI unit and multiple RRU devices.

[0077] The present application also provides a control method for a cross-polarization leaky cable MIMO communication system, which can particularly reduce interference between adjacent frequency signals of different operators, as shown in the flowchart in FIG5 , including the steps of:

[0078] S01: Receive signals of different standards and frequency bands from different operators;

[0079] S02: Combine signals of different frequency bands of 2G / 3G / 4G standards into signal pairs, and determine whether the signal pairs will cause adjacent channel interference or intermodulation interference;

[0080] S03: Feed signals of different frequency bands of the 5G / 6G standard into all leaky cables, and feed signals of different frequency bands of the 2G / 3G / 4G standard in the signal pair that generates interference into different leaky cables respectively. The radiation polarization directions of two adjacent leaky cables are different.

[0081] For example, the combination of China Telecom's CDMA800 signal and China Telecom's FDD-LTE2.1 signal will produce intermodulation interference and cannot be fed into the same leaky cable. China Telecom's CDMA800 signal is accessed to the first POI 14 and the fourth POI 17, and the signal is fed into the first vertical polarization leaky cable 18 and the second horizontal polarization leaky cable 21; China Telecom's FDD-LTE2.1 signal is accessed to the second POI 15 and the third POI 16, and the signal is fed into the first horizontal polarization leaky cable 19 and the second vertical polarization leaky cable 20.

[0082] For example, the FDD-LTE1.8 standard signal of China Mobile and the FDD-LTE1.8 standard signal of China Unicom cannot be combined to generate adjacent channel interference and cannot be fed into the same leaky cable. The FDD-LTE1.8 standard signal of China Mobile is accessed to the first POI 14 and the third POI 16, and the signal is fed into the first vertical polarization leaky cable 18 and the second vertical polarization leaky cable 20; the FDD-LTE1.8 standard signal of China Unicom is accessed to the second POI 15 and the fourth POI 17, and the signal is fed into the first horizontal polarization leaky cable 19 and the second horizontal polarization leaky cable 21.

[0083] Wherein, in step S02, the calculation method of the adjacent frequency is that the difference between the lower limit frequency of the high frequency band and the upper limit frequency of the low frequency band of two signals of different standards and different frequency bands is ≤1MHz. Specifically, judging whether the signal pair will cause adjacent frequency interference includes the steps of: obtaining the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal; determining that the signal pair will cause adjacent frequency interference based on the fact that the first frequency upper limit is less than the second frequency upper limit, and the difference between the second frequency lower limit and the first frequency upper limit is not greater than 1MHz; or determining that the signal pair will cause adjacent frequency interference based on the fact that the first frequency upper limit is greater than the second frequency upper limit, and the difference between the first frequency lower limit and the second frequency upper limit is not greater than 1MHz.

[0084] In step S02, determining whether the signal pair will generate intermodulation interference includes the steps of: obtaining a first frequency upper limit and a first frequency lower limit of the frequency band of the first signal in the signal pair, and a second frequency upper limit and a second frequency lower limit of the frequency band of the second signal; and determining whether the signal pair will generate intermodulation interference according to the intermodulation interference formula |m1F1±m2F2±···±m n F n |Calculate the frequency of intermodulation interference between the signal pairs, where m1±m2···±m n +n≤9,m n ≤8,n≤9,m n and n is a positive integer, F n It is any one of the first upper frequency limit, the first lower frequency limit, the second upper frequency limit, and the second lower frequency limit.

[0085] A cross-polarization leaky cable MIMO communication system provided in this embodiment can be applied to the coverage of 2G / 3G / 4G / 5G / 6G signals. By receiving signals of different standards and different frequency bands from different operators, and processing 2G / 3G / 4G and 5G / 6G signals separately, the signals of different frequency bands of the 5G / 6G standard are fed into all leaky cables, thereby ensuring the power of the 5G / 6G signal and improving the network coverage and download rate of the 5G / 6G signal; the signals of different frequency bands of the 2G / 3G / 4G standard are combined in pairs to form a signal pair, and it is determined whether the signal pair will generate adjacent channel interference or intermodulation interference. The signals of different standards in the combination of signals of different standards that generate interference are fed into different leaky cables respectively. On the one hand, adjacent channel interference between adjacent frequency signals in the same leaky cable can be avoided, or intermodulation interference between different signals can be avoided, thereby reducing signal interference and improving communication quality. On the other hand, the radiation polarization directions of two adjacent leaky cables are different, which reduces the minimum installation distance between the cables, thereby saving the space required for the installation of the leaky cables. More leaky cables can also be arranged, increasing the number of user access and improving the quality of communication.

[0086] Example 2:

[0087] In some other embodiments, the number of POI devices can be combined, for example, multiple POIs are integrated into one POI unit. For example, there is only one POI, and POI 6 can include multiple POI output units, each POI output unit corresponds to a leaky cable, and is a device that combines and outputs multiple RRU signals in the downstream direction and receives and outputs the upstream signals in a branched manner to the corresponding receiver.

[0088] As shown in Figure 6, a cross-polarization leaky cable MIMO communication system for reducing interference meets the coverage requirements of 2G / 3G / 4G / 5G / 6G. It includes RRU equipment, POI 6 (multi-system access combining platform), and multiple leaky cables. The RRU equipment includes China Telecom CDMA RRU 7, China Mobile FDD-LTE1.8 RRU 8, China Unicom FDD-LTE1.8 RRU 9, China Telecom FDD-LTE2.1 RRU 10, China Mobile TD(E) RRU 11, China Mobile NR2.6 RRU 12, and China Telecom and China Unicom NR3.5 RRU 13. In this example, there are four leaky cables: a first vertically polarized leaky cable 18, a first horizontally polarized leaky cable 19, a second vertically polarized leaky cable 20, and a second horizontally polarized leaky cable 21. Adjacent leaky cables have different radiation polarization directions. The corresponding POI 6 contains four POI output units, each corresponding to a leaky cable. As for other contents of the polarization scheme of the leaky cable, reference may be made to the description in Example 1, which will not be repeated here.

[0089] In some other embodiments, the POI devices may also be divided into four, for example, a first POI 14, a second POI 15, a third POI 16, and a fourth POI 17. As shown in FIG2 above, the first POI 14 is connected to the first vertically polarized leaky cable 18, the second POI 15 is connected to the first horizontally polarized leaky cable 19, the third POI 16 is connected to the second vertically polarized leaky cable 20, and the fourth POI 17 is connected to the second horizontally polarized leaky cable 21. The remaining contents refer to the description in Example 1 and are not repeated here.

[0090] As shown in Figure 6, this embodiment also includes a signal receiving module 22, an interference combination screening module 23, and a leaky cable feed control module 24. The China Telecom CDMA RRU 7, China Mobile FDD-LTE1.8 RRU 8, China Unicom FDD-LTE1.8 RRU 9, China Telecom FDD-LTE2.1 RRU 10, China Mobile TD(E) RRU 11, China Mobile NR2.6 RRU 12, and China Telecom and China Unicom NR3.5 RRU 13 are all signal-connected to the signal receiving module 22. The signal receiving module 22 is signal-connected to the interference combination screening module 23 and the leaky cable feed control module 24. The interference combination screening module 23 is signal-connected to the leaky cable feed control module 24, and the leaky cable feed control module 24 is signal-connected to the POI 6. For example, the leaky cable feed control module 24 is connected to the POI output unit corresponding to each leaky cable in the POI 6. The POI 6 is signal-connected to multiple leaky cables. The signal receiving module 22 is used to receive signals of different standards from different operators. The interference combination screening module 23 is used to combine signals of different frequency bands of the 2G / 3G / 4G standards into signal pairs and determine whether the signal pairs will cause adjacent channel interference or intermodulation interference. The leaky cable feeding control module 24 is connected to the interference combination screening module 23, the signal receiving module 22, and the POI 6. It is used to feed signals of different frequency bands of the 5G / 6G standards into all POI output units in the POI 6, thereby feeding them into all leaky cables. The signals of different frequency bands of the 2G, 3G, and 4G standards in the signal pairs that cause interference are respectively fed into different POI output units in the POI 6, thereby feeding them into different leaky cables.

[0091] As shown in Figure 7, the signal receiving module 22, the interference combination screening module 23 and the leaky cable feeding control module 24 can be integrated into one module, for example, a control unit 25. The interference combination screening module 23 also includes an adjacent frequency interference judgment module 26. The adjacent frequency interference judgment module 26 is used to determine whether the signal pair will generate adjacent frequency interference. Specifically, the adjacent frequency interference judgment module 26 is used to obtain the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal; according to the first frequency upper limit being less than the second frequency upper limit, and the difference between the second frequency lower limit and the first frequency upper limit is not greater than 1MHz, or according to the first frequency upper limit being greater than the second frequency upper limit, and the difference between the first frequency lower limit and the second frequency upper limit is not greater than 1MHz, it is determined that the signal pair will generate adjacent frequency interference. The interference combination screening module 23 also includes an intermodulation interference judgment module 27. The intermodulation interference judgment module 27 is used to determine whether the signal pair will generate intermodulation interference. Specifically, the intermodulation interference judgment module 27 is used to obtain the first frequency upper limit and the first frequency lower limit of the frequency band of the first signal in the signal pair, and the second frequency upper limit and the second frequency lower limit of the frequency band of the second signal; according to the intermodulation interference formula |m1F1±m2F2±···±m nF n |Calculate the frequency of intermodulation interference between the signal pairs, where m1±m2···±m n +n≤9,m n ≤8,n≤9,m n and n is a positive integer, F n Any one of the first frequency upper limit, the first frequency lower limit, the second frequency upper limit and the second frequency lower limit; according to the above-mentioned frequency generating intermodulation interference falling within the frequency band of signals of different standards and different frequency bands from different operators, it is determined that the signal pair will generate intermodulation interference.

[0092] The embodiment in Figure 6 modularizes signal reception, interference combination screening, and leaky cable feed control. However, in Figure 2, to facilitate understanding of the intent of this application, signal reception, interference combination screening, and leaky cable feed control are directly represented by coaxial cable connections, forming a fixed configuration. It can also be understood that the embodiment in Figure 2 is merely a solidification of the configuration in Figure 6 for ease of understanding.

[0093] In the present embodiment, the signal receiving module 22, the interference combination screening module 23, and the leaky cable feeding control module 24 can be a control circuit based on a processor, and are made into a structure of a PCB board. The processor can be an MCU (micro control unit), an SCM (single chip microcomputer), a central processing unit (CPU), a digital signal processor (DSP), or other forms of processing units (such as field programmable gate arrays (FPGAs)) with data processing capabilities and / or program execution capabilities. For example, the central processing unit (CPU) can be an X86 or ARM architecture. The processor can be a general-purpose processor or a dedicated processor. The combination of interference (adjacent frequency interference and intermodulation interference) is screened out by processor control, and the different signals in the interference combination are controlled to enter different leaky cables to achieve path configuration, such as being configured as the path in Figure 2. In some embodiments, at least one of the signal receiving module 22, the interference combination screening module 23, and the leaky cable feeding control module 24 can be integrated with the POI device, or is only a software / hardware module in the POI device. Other modules or descriptions refer to Example 1 and are not repeated here.

[0094] A cross-polarization leaky cable MIMO communication system for reducing interference provided in this embodiment meets the coverage of 2G / 3G / 4G / 5G / 6G signals, and is provided with a signal receiving module 22, an interference combination screening module 23, and a leaky cable feeding control module 24, connecting RRU devices of different operators to receive signals of different standards and different frequency bands from different operators, feeding signals of different frequency bands of the 5G / 6G standard into all leaky cables, and judging whether the pairwise combination of signals of different frequency bands of 2G / 3G / 4G will generate adjacent channel interference and intermodulation interference, and feeding signals of different standards and different frequencies in the combination of signals of different frequency bands of 2G / 3G / 4G that generate interference into different leaky cables through POI, thereby realizing the setting and control of links from RRU devices of different operators to POI input ports, avoiding adjacent frequency signals and signals that generate interference from being fed into the same leaky cable, reducing signal interference, and improving communication quality. In addition, the radiation polarization directions of two adjacent leaky cables are different, which reduces the requirements for the distance between the leaky cables, facilitates construction and installation, and allows more leaky cables to be deployed, increasing the number of user access and improving the quality of communication.

[0095] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A cross-polarization leaky cable MIMO communication system, characterized in that: include: A plurality of RRU devices, a plurality of POIs and a plurality of leaky cables arranged side by side, wherein the radiation polarization directions of the two adjacent leaky cables are different; The POI signal is connected to the leaky cable, and each POI is connected to a leaky cable signal; The RRU device is connected to the POI signal, wherein the RRU device signal of the 5G / 6G standard is connected to all the POIs; the RRU device signal of the 2G / 3G / 4G standard in which the adjacent channel interference or intermodulation interference exists is connected to different POIs.

2. A cross-polarization leaky cable MIMO communication system according to claim 1, characterized in that: It also includes a control unit, which is connected between the RRU device and the POI. The control unit is used to receive signals of different standards and different frequency bands from different operators of the multiple RRU devices, combine the signals of different frequency bands of the 2G / 3G / 4G standards in pairs to form signal pairs, determine whether the signal pairs will cause adjacent channel interference or intermodulation interference, and feed the signals of different frequency bands of the 5G / 6G standards into all POIs, and feed the signals of different frequency bands of the 2G / 3G / 4G standards in the signal pairs that cause interference into different POIs respectively.

3. A cross-polarization leaky cable MIMO communication system according to claim 2, characterized in that: The control unit also includes an adjacent frequency interference judgment module, which is used to obtain a first frequency upper limit and a first frequency lower limit of the frequency band of the first signal in the signal pair, and a second frequency upper limit and a second frequency lower limit of the frequency band of the second signal; according to the first frequency upper limit being less than the second frequency upper limit, and the difference between the second frequency lower limit and the first frequency upper limit being no greater than 1 MHz, or according to the first frequency upper limit being greater than the second frequency upper limit, and the difference between the first frequency lower limit and the second frequency upper limit being no greater than 1 MHz, it is determined that the signal pair will cause adjacent frequency interference.

4. A cross-polarization leaky cable MIMO communication system according to claim 2 or 3, characterized in that: The control unit also includes an intermodulation interference judgment module, which is used to obtain a first frequency upper limit and a first frequency lower limit of the frequency band of the first signal in the signal pair, and a second frequency upper limit and a second frequency lower limit of the frequency band of the second signal; according to the intermodulation interference formula |m1F1±m2F2±···±m n F n | Calculate the frequency at which the signal pair produces intermodulation interference, where m1±m2···±m n +n≤9,m n ≤8,n≤9,m n and n is a positive integer, F n Any one of the first frequency upper limit, the first frequency lower limit, the second frequency upper limit and the second frequency lower limit; according to the above-mentioned frequency generating intermodulation interference falling into the frequency band of signals of different standards and different frequency bands from different operators, it is determined that the signal pair will generate intermodulation interference.

5. A cross-polarization leaky cable MIMO communication system according to any one of claims 2 to 4, characterized in that: The control unit and the multiple POIs are integrated into one unit; or, the multiple POIs are integrated into one POI unit, and the control unit is connected between the multiple RRU devices and the POI unit.

6. A cross-polarization leaky cable MIMO communication system according to any one of claims 1 to 5, characterized in that: The RRU device of 2G / 3G / 4G standard can be connected to two POIs by signals at most.

7. A cross-polarization leaky cable MIMO communication system according to any one of claims 1 to 6, characterized in that: The polarization direction of the leaky cable is vertical polarization, horizontal polarization, +45° polarization or -45° polarization.

8. A cross-polarization leaky cable MIMO communication system according to any one of claims 1 or 7, characterized in that: The radiation polarization directions of the plurality of leaky cables are arranged alternately in a horizontal polarization and a vertical polarization manner.

9. A cross-polarization leaky cable MIMO communication system according to claim 8, characterized in that: Signals of different frequency bands of 2G / 3G / 4G standards are combined in pairs to form signal pairs, and the two signals in the signal pair that generate adjacent channel interference or intermodulation interference are respectively fed into different leaky cables of the same polarization mode through different POIs.

10. A cross-polarization leaky cable MIMO communication system, characterized in that: It includes an RRU device, a POI and a plurality of leaky cables arranged side by side, wherein the radiation polarization directions of the two adjacent leaky cables are different, and the POI signal is connected to the leaky cables; It also includes: a signal receiving module, connected to the RRU device, and used to receive signals of different standards and different frequency bands from different operators of the RRU device; The interference combination screening module is connected to the signal receiving module and is used to combine signals of different frequency bands of 2G / 3G / 4G standards in pairs to form signal pairs, and determine whether the signal pairs will cause adjacent frequency interference or intermodulation interference; The leaky cable feeding control module is connected to the interference combination screening module, the signal receiving module and the POI, and is used to feed the signals of different frequency bands of the 5G / 6G standard into all the leaky cables through the POI, and to feed the signals of different frequency bands of the 2G, 3G and 4G standards in the signal pair that generates interference into different leaky cables through the POI.

11. A cross-polarization leaky cable MIMO communication system, characterized in that: Including RRU devices of different standards and frequency bands of China Unicom, China Mobile and China Telecom, a first POI, a second POI, a third POI, a fourth POI and four leaky cables arranged side by side, the radiation polarization directions of the leaky cables adjacent to each other are different, and each POI device is connected to a leaky cable separately; All 5G / 6G RRU device signals in the RRU device are connected to all POI devices, and 2G / 3G / 4G RRU device signals that generate adjacent channel interference or intermodulation interference in the RRU device are connected to different POI devices.

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