Micro-distribution system and method for automatically adjusting link insertion loss

Abstract

The invention provides a micro-distribution system and a method for automatically adjusting link insertion loss, which can solve the problems that the input signal of a short branch coverage unit is too strong and the input signal of a long branch coverage unit is insufficient due to different lengths of radio frequency cables of branches, and an expansion unit comprises a plurality of signal output ports and a signal attenuator; the coverage unit is configured to measure the input signal strength of a signal received by the coverage unit and report the measured input signal strength to the main control unit; the main control unit is configured to receive input signal strength reported by the plurality of coverage units, calculate a corresponding attenuation adjustment value for each coverage unit according to a preset signal strength target value, generate a control instruction and send the control instruction to the expansion unit; the expansion unit is configured to receive the control instruction from the main control unit and adjust the attenuation amount of the signal attenuator according to the attenuation adjustment value in the control instruction.

Description

Technical Field

[0001] This invention relates to the field of wireless communication signal coverage technology, and in particular to a micro-distribution system for mobile communication networks and a method for automatically adjusting link insertion loss. Background Technology

[0002] Micro-distribution systems are a common solution for deep signal coverage in indoor or regional settings, used to address signal blind spots or weak areas in large buildings, underground parking lots, shopping malls, and other similar locations.

[0003] Currently, most micro-distribution systems on the market use multi-stage power dividers and combiners to achieve a one-to-many effect in their expansion units, ensuring that the output signal from the main control unit has virtually identical strength at each output port of the expansion unit. However, in actual engineering deployments, due to limitations in building structure and cabling conditions, the length of the RF cables from the expansion unit to each coverage unit often varies significantly. For example, some coverage units may be only ten meters or so away from the expansion unit, while others may be nearly a hundred meters away.

[0004] The significant difference in RF cable length between the extension unit and the coverage unit leads to a proportional attenuation of the RF signal during transmission through the coaxial cable, known as link insertion loss. For coverage units connected by short cables, excessively strong input signals may exceed the amplifier's linear operating range or even the device's damage threshold. This can cause the amplifier in that coverage unit to operate in the non-linear region, resulting in gain compression and error vector magnitude (EVM) degradation. In severe cases, it can even burn out front-end devices, leading to permanent equipment damage. A common approach to protect coverage units with short branches is to reduce the total output power of the main control unit. However, this one-size-fits-all solution results in insufficient input signal strength for coverage units connected by long cables, preventing effective amplification and failing to improve the signal strength in the micro-distribution coverage area. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a micro-distribution system and a method for automatically adjusting link insertion loss. This system can solve the problem of excessively strong input signals in short-branch coverage units and insufficient input signals in long-branch coverage units caused by varying lengths of RF cables in each branch, ensuring safe system operation and optimizing overall signal coverage quality.

[0006] The technical solution is as follows: a micro-distributed system includes a main control unit, at least one expansion unit, and multiple coverage units connected together. Each coverage unit is connected to the expansion unit via a different signal branch. Its characteristic is that: The expansion unit includes multiple signal output ports and signal attenuators respectively disposed on the signal branches corresponding to the signal output ports; The coverage unit is configured to measure the input signal strength of the signal it receives and report the measured input signal strength to the main control unit; the main control unit is configured to receive the input signal strength reported by the multiple coverage units, calculate a corresponding attenuation adjustment value for each coverage unit according to a preset signal strength target value, generate a control command and send it to the extension unit; the extension unit is configured to receive the control command from the main control unit and adjust the attenuation of the signal attenuator according to the attenuation adjustment value in the control command.

[0007] Furthermore, the expansion unit also includes: The signal input port is used to receive signals from the main control unit; A signal distribution network, wherein the input end of the signal distribution network is connected to the signal input port; the output end of the signal distribution network is respectively connected to the signal output port, and the signal distribution network distributes the signal input from the signal input port to multiple signal output ports; The signal attenuators are respectively disposed between the signal distribution network and the signal output port.

[0008] Furthermore, the main control unit communicates with the expansion unit and the expansion unit, as well as with the coverage unit, via radio frequency cables, and the intra-band communication uses FSK modulation.

[0009] Furthermore, the signal distribution network includes a multi-stage power divider for distributing the input signal to multiple output terminals.

[0010] Furthermore, a DC blocking capacitor is connected in series on the signal branch and after the signal attenuator. An inductor is connected between the DC blocking capacitor and the power supply to isolate the radio frequency signal from the DC link.

[0011] A method for automatically adjusting link insertion loss, characterized by being implemented based on the aforementioned micro-distributed system, comprising the following steps: Step S1: The coverage unit measures its own input signal strength; Step S2: The coverage unit reports the measured input signal strength value to the main control unit; Step S3: The main control unit compares the received input signal strength value with the preset signal strength target value and calculates the target attenuation amount required for the coverage unit; Step S4: The main control unit sends a control command containing the target attenuation amount to the expansion unit; Step S5: The extension unit adjusts the attenuation value of the corresponding signal attenuator to the target attenuation value according to the control command.

[0012] Furthermore, before step S1, the system includes the following step: after the system is powered on, the main control unit controls the expansion unit to set all signal attenuators to a preset initial attenuation value.

[0013] Furthermore, the preset initial attenuation is the difference between the signal attenuation of the longest branch and the signal attenuation of the shortest branch in the signal branch connecting the main control unit and the coverage unit.

[0014] Furthermore, the method for calculating the target attenuation in step S3 is as follows: when the received input signal strength value is lower than the preset signal strength target value, the target attenuation is calculated. ; in, This is the current decay amount. The target value for signal strength. The reported input signal strength value, This indicates rounding; when the received input signal strength value is higher than or equal to the preset signal strength target value, the current attenuation amount is kept unchanged as the target attenuation amount.

[0015] Furthermore, the preset signal strength target value in step S3 is the ALC start-up threshold of the coverage unit.

[0016] This invention, by independently setting signal attenuators on each signal branch of the extension unit, can precisely control the signal strength reaching each coverage unit. This effectively solves the problem of excessively strong input signals in short branches, ensuring that the input signal strength of the coverage unit remains within a safe range, protecting equipment components from damage, and avoiding amplifier damage or operation in the nonlinear region due to excessively strong input signals. While ensuring the safety of short branches, differential adjustment avoids excessive attenuation of signals in long branches, allowing coverage units in long branches to also obtain sufficient input signal strength. This effectively improves the signal strength and signal quality of the entire coverage area, optimizing the overall system performance. By adjusting the attenuation of each signal branch, it ensures that each level of coverage unit can operate near its maximum gain, fully utilizing the equipment performance. Furthermore, by employing the automatic link insertion loss adjustment method of this invention, after the system is installed, there is no need for manual measurement and debugging of the attenuation of each branch. The link insertion loss can be automatically optimized, greatly reducing deployment difficulty, time, and manpower costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall architecture of the micro-distribution system in an embodiment of the present invention; Figure 2 This is a functional block diagram of the main control unit in an embodiment of the present invention; Figure 3This is a functional block diagram of the covering unit in an embodiment of the present invention; Figure 4 This is a functional block diagram of the extension unit in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the steps of the method for automatically adjusting link insertion loss in an embodiment of the present invention. Detailed Implementation

[0018] Please see Figure 1 This embodiment provides a micro-distribution system, which includes a main control unit 100, an expansion unit 200 and multiple coverage units 300. The main control unit 100 is connected to the expansion unit 200 through radio frequency cables, and the expansion unit 200 is connected to multiple coverage units 300 through multiple independent radio frequency cables to form different signal branches and form a star or tree topology.

[0019] The main control unit 100 obtains the downlink signal from the base station, amplifies it, and transmits it to the extension unit 200. The extension unit 200 distributes the signal to each coverage unit 300. The coverage unit 300 amplifies the signal and transmits it through an antenna to cover the target area. The system in this embodiment also supports the uplink, whose transmission direction is opposite to that of the downlink, but the principle is similar. This specification mainly uses the downlink as an example for explanation.

[0020] like Figure 2 As shown, the main control unit 100 contains multiple frequency band radio frequency amplification links to adapt to different signal standards such as 4G and 5G. The main control unit includes a synchronization module to support different signal standards. The TDD standard requires a synchronization module. The main control unit 100 includes a CPU and integrates various communication modules, including an FSK communication module for in-band communication with lower-level devices, and Bluetooth, WiFi, and LTE modules for local maintenance or remote network management. The CPU is responsible for receiving the input signal strength information reported by all coverage units, executing decision algorithms to calculate the target attenuation required for each branch, and generating control commands.

[0021] like Figure 3 As shown, the internal structure of the coverage unit 300 is similar to that of the main control unit, and it also includes an RF amplification link, a synchronization module and a CPU. The CPU of the coverage unit 300 uses the detector or ADC sampling circuit in the link to measure its own RF input signal strength. The coverage unit 300 in the embodiment is also equipped with an FSK communication module, a Bluetooth communication module and a WiFi communication module. The FSK communication module is used to report the measured input signal strength data to the main control unit 100.

[0022] Please see Figure 4The core improvement of this invention is reflected in the design of the expansion unit 200. In this embodiment, the expansion unit 200 with one input port 201 and eight output ports 207 is taken as an example.

[0023] After the signal enters through the signal input port 201, it is distributed through a 1-to-8 power distribution network 202 consisting of seven 1-to-2 power dividers. Crucially, before the signal is connected to the power supply link after distribution, a signal attenuator 203 is connected in series on each signal branch. Each signal attenuator 203 is controlled by the CPU inside the expansion unit 200. After the signal attenuator 203, a DC blocking capacitor 204 is provided. An inductor 206 is also provided between the DC blocking capacitor 204 and the power module 205. The DC blocking capacitor 204 is used to isolate the RF path from the DC power supply path from the power module 205, preventing DC voltage from affecting the attenuator's performance. In this embodiment, the expansion unit 200 also includes an FSK communication module for receiving control commands from the main control unit 100 and transmitting them to the CPU to adjust each signal attenuator 203. In MIMO-supporting applications, the expansion unit can be designed with two signal input ports and two sets of signal output ports, with each output branch also configured with an independent signal attenuator.

[0024] In this embodiment, the main control unit 100, the expansion unit 200 and the coverage unit 300 communicate in-band via radio frequency cables. The in-band communication uses FSK modulation, which is to superimpose low-frequency FSK modulated data signals onto the radio frequency signals. No additional communication cables need to be laid, and bidirectional data communication can be achieved using existing radio frequency cables.

[0025] In this embodiment, the system's workflow is as follows: The main control unit 100 receives the base station signal, amplifies it, and then outputs it. The signal is transmitted to the expansion unit 200 via an RF cable. The signal distribution network 201 of the expansion unit 200 distributes the signal to multiple signal branches. The signal of each signal branch is attenuated by the signal attenuator 203. The adjusted signal is output from the signal output port 207 after passing through the DC blocking capacitor 204. The signal is transmitted to the corresponding coverage unit 300 via an RF cable. The coverage unit 300 amplifies the signal and transmits it through the antenna.

[0026] Please see Figure 4 In an embodiment of the present invention, a method for automatically adjusting link insertion loss is also provided, which is implemented based on the micro-distributed system in the above embodiments. The method includes the following steps: Step S1: The coverage unit measures its own input signal strength; Step S2: The coverage unit reports the measured input signal strength value to the main control unit; Step S3: The main control unit compares the received input signal strength value with the preset signal strength target value and calculates the target attenuation amount required for the coverage unit; Step S4: The main control unit sends a control command containing the target attenuation amount to the expansion unit; Step S5: The expansion unit adjusts the attenuation value of the corresponding signal attenuator to the target attenuation value according to the control command.

[0027] In one embodiment of the present invention, the method includes the following steps: after the system is powered on, the main control unit controls the expansion unit to set all signal attenuators to a preset initial attenuation amount. In this embodiment, the preset initial attenuation amount is the difference between the signal attenuation of the longest branch and the signal attenuation of the shortest branch in the signal branches connected between the main control unit and the coverage unit.

[0028] After initialization, each coverage unit 300 begins normal operation, and each coverage unit 300 measures the input signal strength of the radio frequency signal it receives. ; Each coverage unit 300 will measure the input signal strength value The signal is encoded by the FSK communication module, superimposed on the radio frequency signal, and relayed to the main control unit 100 via the extension unit 200. After receiving the input signal strength values ​​reported by each coverage unit 300, the main control unit 100 compares them with the preset signal strength target value. In a comparison, in this embodiment, when the received input signal strength value is lower than a preset signal strength target value, the target attenuation amount is calculated. ; in, This is the current decay amount. The target value for signal strength. The reported input signal strength value, For the target attenuation amount, This indicates rounding, because the step size of the signal attenuator is 1dB, which requires rounding. In the embodiment, the preset signal strength target value is the ALC start control threshold of the coverage unit. When the received input signal strength value is higher than or equal to the preset signal strength target value, it indicates that the input signal of the coverage unit of the corresponding signal branch has met the standard or is too strong. In order to ensure safety and maximum output power, the current attenuation amount is kept unchanged as the target attenuation amount.

[0029] The main control unit 100 encapsulates the target attenuation calculated for each branch into a control command and sends it to the expansion unit 200 via FSK communication. The control command includes the number of each branch and the corresponding target attenuation.

[0030] After receiving the control command, the extension unit 200 parses the target attenuation of each branch and controls the corresponding signal attenuator 202 to adjust to the specified attenuation value.

[0031] This invention, by independently setting a signal attenuator on each signal branch of the expansion unit, can precisely control the signal strength reaching each coverage unit, effectively solving the problem of excessively strong short-branch signal input, ensuring that the input signal strength of the coverage unit is always within a safe range, protecting the equipment from damage, and avoiding problems such as amplifier damage or operation in the nonlinear region due to excessively strong input signals. By adjusting the attenuation of each signal branch, it is ensured that each level of coverage unit can operate at near maximum gain, fully utilize the equipment performance, and avoid gain compression and EVM degradation. At the same time, differential adjustment avoids excessive attenuation of long branch signals, so that the coverage unit of long branch can also obtain sufficient input signal strength, thereby improving the signal strength and signal quality of the entire coverage area. The system can automatically optimize its functions. After installation, no manual intervention is required. The coverage unit automatically collects and reports the input signal strength to the main control unit. The main control unit automatically calculates and sends the attenuation adjustment value of each branch to the extension unit based on the information reported by each branch. This greatly reduces the complexity, time and manpower costs of engineering deployment. The system can also dynamically respond to the impact of environmental changes and continuously maintain the optimal working state, making the system run more safely and stably.

[0032] The optimization method of the present invention will be described in detail below through a specific numerical example.

[0033] System parameter settings: Main control unit 100 gain: 70dB, maximum output power: 20dBm Coverage Unit 300 Gain: 70dB, Maximum Output Power: 20dBm ALC start-up threshold for Cover Unit 300: -50dBm The maximum safe input signal strength of the coverage unit 300 is -10dBm. Attenuation is set when the input signal strength of the coverage unit exceeds the control depth by 10dB.

[0034] Table 1 shows the insertion loss values ​​of the extended unit at different frequency bands, and Table 2 shows the signal attenuation values ​​of branches with different line lengths in the micro-distributed system.

[0035] Table 1: Insertion loss values ​​of the extended unit at different frequency bands (unit: dB) Table 2: Signal attenuation values ​​of branches with different line lengths in a micro-distributed system (unit: dB) (including insertion loss of extended units) This embodiment uses a center frequency of 2565MHz as an example. The system has one shortest branch and one longest branch. The shortest branch is: Cable length from main control unit to expansion unit: 0.5 meters; Cable length from expansion unit to coverage unit: 10 meters; Total cable length: 10.5 meters.

[0036] The total signal attenuation value of the shortest branch is shown in Table 3 below.

[0037] Table 3: Total signal attenuation of the shortest branch The signal attenuation is calculated as the insertion loss of the expansion unit plus the loss over 10.5 meters of cable. The insertion loss of the expansion unit at port 1 in the 2565MHz band is 14.69dB, and the loss of the 10.5-meter cable is approximately 6dB. The total attenuation of the shortest branch is: L short =14.69+6=20.69dB; Longest branch: Cable length from main control unit to expansion unit: 10.5 meters; Cable length from expansion unit to coverage unit: 80 meters; Total cable length: 90.5 meters; The signal attenuation is referenced as the insertion loss of the extension unit + the line loss of 90.5 meters. According to the data in Table 2, the total attenuation value L of the longest branch in the 2565MHz band is... long It is 66.1dB.

[0038] The difference in attenuation between the longest and shortest branches is: ΔL = 66.1 - 20.69 = 45.41 dB ≈ 45 dB.

[0039] The method for automatically adjusting link insertion loss in the embodiment is specifically executed as follows: After the system is powered on, the main control unit 100 controls the expansion unit 200 to set all signal attenuators 202 to an initial attenuation of 45dB.

[0040] After initialization, the main control unit 100 outputs 20dBm.

[0041] For the shortest branch, the input signal strength received by the coverage unit is: P in_short =20dBm-L short -ATT current =20-20.69-45=-45.69dBm; Without a signal attenuator, the input signal strength of the signal branch coverage unit would be: 20 - 20.69 = -0.69 dBm; at this point, the signal strength value far exceeds the maximum safe input signal strength of the coverage unit -10 dBm, with an excess of: -0.69 - (-10) = 9.31 dB; at this point, the coverage unit can no longer function properly. Most devices will automatically shut down the RF link to protect the hardware, or the amplifier will operate in a severely nonlinear region, resulting in gain compression and EVM degradation. By increasing the initial attenuation by 45 dB, the input signal strength drops to -45.69 dBm, which is within the safe range. For the longest branch, the input signal strength received by the coverage unit is: P in_long =20dBm-L long -ATT current =20-66.1-45=-91.1dBm; Each coverage unit 300 reports its measured input signal strength value to the main control unit 100.

[0042] After receiving the input signal strength values ​​reported by each coverage unit, the main control unit 100 compares them with the preset signal strength target value P. target = -50dBm for comparison.

[0043] For the shortest branch: P in_short =-45.69dBm>P target =-50dBm indicates that the input signal strength of the signal branch is higher than the target value, but still within the safe range. The current input power of the coverage unit of this signal branch is higher than the ALC start-up value: -45.69-(-50)=4.31dB. The ALC function of the coverage unit has been activated, automatically reducing a certain gain to maintain stable output power. The coverage unit has reached the maximum output power. In order to ensure safety and maximum output, the main control unit decides to keep the attenuation of the corresponding signal branch unchanged at 45dB. For the longest branch: P in_long -91.1dBm <P target =-50dBm indicates that the input signal of this signal branch is severely insufficient, and the attenuation needs to be reduced. Calculate according to the formula: ; ATT new =45-⌊(-50-(-91.1))⌋=45-⌊41.1⌋=45-41=4dB The main control unit 100 sends a control command to the expansion unit 200. The command includes: the shortest branch signal attenuation is 45dB and the longest branch signal attenuation is 4dB. After receiving the command, the expansion unit 200 keeps the signal attenuator of the shortest branch at 45dB and adjusts the signal attenuator of the longest branch to 4dB.

[0044] After adjustment, the input signal strength of the coverage unit of the shortest branch remains at: P in_short =20-20.69-45=-45.69dBm; The coverage unit operates stably at maximum output power under ALC control, and the input signal is within a safe range, so it will not damage the device; The input signal strength of the coverage unit of the longest branch becomes: P in_long =20-66.1-4=-50.1dBm; very close to the ALC start-up threshold of -50dBm, the coverage unit can operate at near maximum gain, fully utilize its amplification capability, and effectively improve the signal coverage strength of the area.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A micro-distributed system, comprising a main control unit, at least one expansion unit, and multiple coverage units connected together, wherein the coverage units are respectively connected to the expansion unit through different signal branches, characterized in that: The expansion unit includes multiple signal output ports and signal attenuators respectively disposed on the signal branches corresponding to the signal output ports; The coverage unit is configured to measure the input signal strength of the signal it receives and report the measured input signal strength to the main control unit; the main control unit is configured to receive the input signal strength reported by the multiple coverage units, calculate a corresponding attenuation adjustment value for each coverage unit according to a preset signal strength target value, generate a control command and send it to the extension unit; the extension unit is configured to receive the control command from the main control unit and adjust the attenuation of the signal attenuator according to the attenuation adjustment value in the control command.

2. The micro-distribution system according to claim 1, characterized in that: The expansion unit also includes: A signal input port is used to receive signals from the main control unit; A signal distribution network, wherein the input end of the signal distribution network is connected to the signal input port; the output end of the signal distribution network is respectively connected to the signal output port, and the signal distribution network distributes the signal input from the signal input port to multiple signal output ports; The signal attenuators are respectively disposed between the signal distribution network and the signal output port.

3. A micro-distribution system according to claim 1, characterized in that: The main control unit communicates with the expansion unit and the expansion unit, as well as with the coverage unit, via radio frequency cables. The intra-band communication uses FSK modulation.

4. A micro-distribution system according to claim 1, characterized in that: The signal distribution network includes a multi-stage power divider for distributing the input signal to multiple output terminals.

5. A micro-distribution system according to claim 1, characterized in that: A DC blocking capacitor is connected in series on the signal branch and after the signal attenuator. An inductor is connected between the DC blocking capacitor and the power supply to isolate the radio frequency signal from the DC link.

6. A method for automatically adjusting link insertion loss, characterized in that, Based on the micro-distribution system according to any one of claims 1 to 5, the method includes the following steps: S1: The coverage unit measures its own input signal strength; S2: The coverage unit reports the measured input signal strength value to the main control unit; S3: The main control unit compares the received input signal strength value with the preset signal strength target value and calculates the target attenuation amount required for the coverage unit; S4: The main control unit sends a control command containing the target attenuation amount to the expansion unit; S5: The expansion unit adjusts the attenuation value of the corresponding signal attenuator to the target attenuation amount according to the control command.

7. The method according to claim 6, characterized in that, Before step S1, the system also includes the following step: after the system is powered on, the main control unit controls the expansion unit to set all signal attenuators to a preset initial attenuation value.

8. The method according to claim 7, characterized in that: The preset initial attenuation is the difference between the signal attenuation of the longest branch and the signal attenuation of the shortest branch in the signal branch connecting the main control unit and the coverage unit.

9. The method according to claim 6, characterized in that: The method for calculating the target attenuation in step S3 is as follows: when the received input signal strength value is lower than the preset signal strength target value, the target attenuation is calculated. ; in, This is the current decay amount. The target value for signal strength. The reported input signal strength value, For the target attenuation amount, This indicates rounding; when the received input signal strength value is higher than or equal to the preset signal strength target value, the current attenuation amount is kept unchanged as the target attenuation amount.

10. The method according to claim 6, characterized in that: The preset signal strength target value in step S3 is the ALC start-up threshold of the coverage unit.

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