Automatic antenna selection circuit based on TDD communication system and TDD communication device

Abstract

The utility model provides an automatic antenna selection circuit based on a TDD communication system and TDD communication equipment. The automatic antenna selection circuit comprises a radio frequency switch, a plurality of coupling detection circuits and a plurality of comparison circuits, a first port of the first coupling detection circuit is connected with a TDD information source, a second port is connected with the input end of the radio frequency switch, and a third port is connected with the first comparison circuit; the first port of the second coupling detection circuit is connected with the first output end of the radio frequency switch, the second port is connected with the first antenna, and the third port is connected with the second comparison circuit; the first port of the third coupling detection circuit is connected with the second output end of the radio frequency switch, the second port is connected with the second antenna, and the third port is connected with the second comparison circuit; the first comparison circuit outputs an enable signal to an enable end of the second comparison circuit according to a comparison result of the first detection signal and the reference signal; the second comparison circuit outputs a control signal to the radio frequency switch according to a comparison result of the second detection signal and the third detection signal.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to an automatic antenna selection circuit and a TDD communication device based on a TDD communication system. Background Technology

[0002] In wireless communication systems, antenna performance directly affects signal reception quality. Traditional wireless communication devices typically use fixed antennas or manually switched antennas, which cannot dynamically select the optimal antenna based on signal strength in real time. This leads to unstable communication quality, especially in environments with severe multipath effects and signal interference, where fixed antennas or manual switching methods are insufficient to meet the demands of high-quality communication.

[0003] To address the aforementioned issues, existing technologies have proposed several automatic antenna selection schemes. However, these schemes are typically complex and costly, and suffer from switching delays and erroneous switching in practical applications. Therefore, there is an urgent need for an automatic antenna selection circuit that is simple in structure, low in cost, fast, efficient, and stable in performance. Utility Model Content

[0004] In view of this, this application proposes an automatic antenna selection circuit and TDD communication device based on a TDD communication system, aiming to achieve low-cost, real-time, and stable automatic antenna selection through hardware circuitry, thereby improving communication quality.

[0005] In a first aspect, this application provides an automatic antenna selection circuit based on a TDD communication system, including a radio frequency switch, multiple coupling detection circuits and multiple comparison circuits, wherein the multiple coupling detection circuits include at least a first coupling detection circuit, a second coupling detection circuit and a third coupling detection circuit, and the multiple comparison circuits include at least a first comparison circuit and a second comparison circuit.

[0006] The first port of the first coupling detector circuit is connected to the TDD source, the second port is connected to the input terminal of the radio frequency switch, and the third port is connected to the first input terminal of the first comparator circuit.

[0007] The first port of the second coupling detector circuit is connected to the first output terminal of the radio frequency switch, the second port is connected to the first antenna, and the third port is connected to the first input terminal of the second comparator circuit.

[0008] The first port of the third coupling detector circuit is connected to the second output terminal of the radio frequency switch, the second port is connected to the second antenna, and the third port is connected to the second input terminal of the second comparator circuit.

[0009] The first input terminal of the first comparator circuit receives the first detected signal output by the first coupled detector circuit, and the second input terminal receives a reference signal. The first comparator circuit outputs an enable signal to the enable terminal of the second comparator circuit according to the comparison result between the first detected signal and the reference signal, so as to control the working state of the second comparator circuit.

[0010] The first input terminal of the second comparator circuit receives the second detection signal output by the second coupled detection circuit, and the second input terminal receives the third detection signal output by the third coupled detection circuit. The second comparator circuit outputs a control signal to the radio frequency switch based on the comparison result of the second detection signal and the third detection signal to control the switching of the radio frequency switch.

[0011] Therefore, this application designs an automatic antenna selection circuit comprising a radio frequency switch, multiple coupled detection circuits, and multiple comparison circuits. The first coupled detection circuit detects the signal of a TDD (Time Division Duplexing) source to obtain the source's state. The first comparison circuit compares the detected signal with a reference signal to output an enable signal for the second comparison circuit. Then, the second and third coupled detection circuits detect the signal energy of the first and second antennas respectively and output the results to the second comparison circuit for comparison. Based on the comparison result, a control signal is output to switch the radio frequency switch, thereby ensuring that the TDD source can use the antenna with the stronger signal for communication. This application has a simple circuit structure, can detect the strength of the received signal in real time, and automatically selects the antenna with the stronger signal for communication, thus improving communication quality.

[0012] Optionally, the radio frequency switch includes a single-pole multi-throw switch, the stationary terminal of which is connected to the second port of the first coupling detector circuit, the first moving terminal of which is connected to the first port of the second coupling detector circuit, and the second moving terminal of which is connected to the first port of the third coupling detector circuit.

[0013] As shown above, by using a single-pole multi-throw switch as the radio frequency switch, the number of moving terminals of the single-pole multi-throw switch can be expanded to N (N≥2) to allow the connection of multiple antennas. By adding coupling detection circuit and comparison circuit channels, real-time detection and intelligent switching of signal strength of multiple antennas can be realized.

[0014] Optionally, the coupling detection circuit includes a microstrip line coupler, a detector, and a low-pass filter;

[0015] The microstrip line coupler is used to extract the received signal energy and output the coupled signal to the detector. The detector is used to convert the coupled signal into a DC level signal and output it after filtering by a low-pass filter.

[0016] As described above, the coupling detector circuit, as the signal transmission circuit at the output or input end of the RF switch, can ensure wide-band coverage and high isolation by using a microstrip line coupler. It couples the signal energy on the transmission line, and after the detector converts the coupled signal into a DC level signal, it is filtered by a low-pass filter so that it can be provided to the comparison circuit at the back end for comparison.

[0017] Optionally, the detector may include a diode detector or a logarithmic detector.

[0018] Therefore, the detector in this application can be a diode detector or a logarithmic detector. The diode detector converts the RF signal power into DC voltage by utilizing the nonlinear characteristics of the Schottky diode, resulting in low power consumption. The logarithmic detector linearly maps the input power into a logarithmic voltage output by using a cascaded limiting amplifier and a logarithmic compression circuit, achieving a dynamic range of up to 60dB.

[0019] Optionally, the comparison circuit includes a high-speed voltage comparator.

[0020] As shown above, by using a high-speed voltage comparator to compare the input detection signal, the system's timing accuracy and signal processing speed can be improved, the magnitude relationship between two input signals can be quickly determined, and high / low level logic signals can be output. Its response time can reach the nanosecond level, and its reference voltage signal is adjustable, thus making it suitable for different signal strengths.

[0021] Optionally, the first coupling detection circuit is used to detect the state of the TDD source;

[0022] When the TDD source is in the transmitting state, the first detection signal output by the first coupling detection circuit is higher than the reference signal, the first comparator circuit outputs a high-level enable signal, and the second comparator circuit does not work.

[0023] When the TDD source is in the receiving state, the first detection signal output by the first coupling detection circuit is lower than the reference signal, the first comparator circuit outputs a low-level enable signal, and the second comparator circuit operates.

[0024] Therefore, in a TDD system, when the TDD source is in the transmit state, switching antennas may affect the ongoing transmission. This application uses a first coupled detector circuit to monitor the RF signal strength of the TDD source in real time. Combined with the coordinated operation of the first and second comparison circuits, intelligent switching control of the transmit / receive states is achieved. Specifically, when the source is transmitting, if the first detector signal is higher than the reference signal, the first comparison circuit outputs a high-level enable signal, and the second comparison circuit is turned off. At this time, the RF switch does not switch. When the source is receiving, if the first detector signal is lower than the reference signal, the first comparison circuit outputs a low-level enable signal, and the second comparison circuit is activated. At this time, the RF switch can switch.

[0025] Optionally, the second coupling detection circuit is used to extract the signal strength of the first antenna and output a second detection signal, and the third coupling detection circuit is used to extract the signal strength of the second antenna and output a third detection signal.

[0026] When the second comparison circuit is working, it outputs a control signal to the radio frequency switch based on the comparison result of the second detection signal and the third detection signal. The control signal is used to control the radio frequency switch to switch to the antenna with a stronger signal so that the TDD signal source can communicate through the antenna with a stronger signal.

[0027] As described above, the signal strengths of the first antenna and the second antenna are extracted by the second coupling detection circuit and the third coupling detection circuit respectively. Combined with the real-time comparison by the second comparison circuit, the radio frequency switch is dynamically controlled to switch to the antenna with the stronger signal based on the comparison result, thereby optimizing the communication performance of the TDD source.

[0028] Secondly, this application provides a TDD communication device, including the above-mentioned automatic antenna selection circuit based on a TDD communication system, for real-time optimization of antenna selection in time-division duplex communication.

[0029] These and other aspects of this application will become more apparent in the description of the following embodiments(s). Attached Figure Description

[0030] Figure 1 A circuit diagram of an automatic antenna selection circuit based on a TDD communication system provided in this application embodiment;

[0031] Figure 2 A circuit diagram of a coupling detector circuit provided in an embodiment of this application.

[0032] It should be understood that the dimensions and shapes of the block diagrams in the above structural diagrams are for reference only and should not constitute an exclusive interpretation of the embodiments of this application. The relative positions and inclusion relationships between the block diagrams presented in the structural diagrams are only schematic representations of the structural relationships between the block diagrams, and are not intended to limit the physical connection methods of the embodiments of this application. Detailed Implementation

[0033] The technical solutions provided in this application will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the system architecture and business scenarios provided in the embodiments of this application are mainly for illustrating possible implementations of the technical solutions of this application and should not be construed as the sole limitation on the technical solutions of this application. Those skilled in the art will recognize that the technical solutions provided in this application are equally applicable to similar technical problems as system architectures evolve and new business scenarios emerge.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0035] This application proposes an automatic antenna selection circuit based on a TDD communication system, aiming to achieve low-cost, real-time, and stable automatic antenna selection through hardware circuitry, thereby improving communication quality.

[0036] like Figure 1 As shown in the figure, an automatic antenna selection circuit based on a TDD communication system provided in this application includes an RF switch SPDT, multiple coupling detection circuits CD1, CD2, CD3 and multiple comparator circuits COM1, COM2;

[0037] The first coupling detector circuit CD1 has its first port connected to the TDD source router, used to couple the radio frequency signal of the TDD source router and convert it into the first detection signal VC1; its second port is connected to the input terminal of the radio frequency switch SPDT; and its third port is connected to the first input terminal of the first comparator circuit COM1. The second coupling detector circuit CD2 has its first port connected to the first output terminal of the radio frequency switch SPDT; its second port is connected to the first antenna E1, used to couple the signal strength of the first antenna E1 and convert it into the second detection signal VC2; and its third port is connected to the first input terminal of the second comparator circuit COM2. The third coupling detector circuit CD3 has its first port connected to the second output terminal of the radio frequency switch SPDT; its second port is connected to the second antenna E2, used to couple the signal strength of the second antenna E2 and convert it into the third detection signal VC3; and its third port is connected to the second input terminal of the second comparator circuit COM2.

[0038] The first input terminal of the first comparator circuit COM1 receives the first detection signal VC1 output by the first coupled detection circuit CD1, and the second input terminal receives a reference signal VCO. The first comparator circuit outputs an enable signal VR to the enable terminal of the second comparator circuit COM2 based on the comparison result of the first detection signal VC1 and the reference signal VCO, so as to control the working state of the second comparator circuit COM2. The first input terminal of the second comparator circuit COM2 receives the second detection signal VC2 output by the second coupled detection circuit, and the second input terminal receives the third detection signal VC3 output by the third coupled detection circuit. The second comparator circuit outputs a control signal VC to the radio frequency switch SPDT based on the comparison result of the second detection signal VC2 and the third detection signal VC3. The control signal VC can control the radio frequency switch SPDT to switch the antenna with a stronger gate signal to ensure that the TDD source can use the antenna with a stronger signal for communication.

[0039] In some embodiments, the RF switch SPDT described in this application can be a high-performance single-pole multi-throw switch. This single-pole multi-throw switch can connect multiple antennas by expanding the number of its moving terminals, and by adding coupling detection circuits and comparator circuit channels, it can achieve real-time detection and intelligent switching of multiple antenna signal strengths. Taking a single-pole double-throw switch as an example, this single-pole double-throw switch has one stationary terminal and two moving terminals, a switching time of less than 100 nanoseconds, an operating frequency range covering 0.1 GHz to 7.5 GHz, and is compatible with 802.11n / g / ac / ax, Halow, and LoRa communication standards. The stationary terminal of this single-pole double-throw switch is connected to the second port of the first coupling detection circuit CD1, one moving terminal of this single-pole double-throw switch is connected to the first port of the second coupling detection circuit CD2, and the other moving terminal of this single-pole double-throw switch is connected to the first port of the third coupling detection circuit CD3. Through this single-pole double-throw switch, dynamic switching between the first antenna E1 and the second antenna E2 can be achieved, thereby ensuring that the TDD signal source can use the antenna with the stronger signal for communication.

[0040] In some embodiments, such as Figure 2 As shown, the coupling detection circuits CD1, CD2, and CD3 of this application can adopt a circuit structure composed of a microstrip line coupler and a diode detector. Specifically, it includes a microstrip line connected between ports P1 and P2, resistors R1 and R2, capacitor C1, and diode D1. The bandwidth of the microstrip line coupler can cover 2.4 GHz to 5.9 GHz, which is suitable for multi-band wireless communication. The coupling degree can be designed to be between -10 dB and -20 dB to ensure effective extraction of signal energy. Resistor R1 can be used to limit the current of the input signal to protect other components in the circuit from the impact of large current. Diode D1 can be used as a detector diode. Capacitor C1 and resistor R2 together form a low-pass filter to achieve filtering of the output signal.

[0041] based on Figure 2 As shown, the working principle of this coupled detection circuit is as follows: the input signal enters through port P1 of the coupled detection circuit, and then passes through resistor R1 and diode D1. Diode D1 filters out the AC component (usually high-frequency component) in the input signal, allowing only the DC component (low-frequency component) to pass through. When the input signal is in the positive half-cycle, diode D1 conducts, allowing current to flow and charge capacitor C1; when the input signal is in the negative half-cycle, diode D1 is cut off, preventing current from flowing. Capacitor C1 is used to store charge and smooth the high-frequency components in the output voltage, making the output voltage more stable. Resistor R2 determines the time constant of the filter, affecting the speed of voltage response. The DC signal after detection and filtering is finally output from port P3 to provide power to the downstream comparator circuit.

[0042] In some embodiments, the coupling detection circuit of this application may also employ a logarithmic detector, which linearly maps the input power to a logarithmic voltage output by using a cascaded limiting amplifier and a logarithmic compression circuit, with a dynamic range of up to 60dB, to meet the requirements of high precision and wide dynamic range.

[0043] In some embodiments, the comparison circuits COM1 and COM2 described above in this application can be high-speed voltage comparators. Through these high-speed voltage comparators, the timing accuracy and signal processing speed of the system can be improved, the magnitude relationship between two input signals can be quickly determined, and high / low level logic signals can be output. The response time can reach the nanosecond level, and the reference voltage signal is adjustable, thus making it suitable for different signal strengths.

[0044] based on Figures 1-2 The working principle of the automatic antenna selection circuit provided in this embodiment of the application is as follows:

[0045] The radio frequency signal of the TDD source Router is coupled through the first coupling detection circuit CD1 and converted into the first detection signal VC1 before being output to the first comparator circuit COM1.

[0046] The first comparator circuit COM1 compares the first detector signal VC1 and the reference signal VC0. If VC1 > VC0, it indicates that the TDD source router is transmitting a signal, and the first comparator circuit COM1 outputs a low-level enable signal VR to activate the second comparator circuit COM2. If VC1 ≤ VC0, it indicates that the TDD source router is not transmitting (or is receiving) a signal, and the first comparator circuit COM1 outputs a high-level enable signal VR to turn off the second comparator circuit COM2.

[0047] The second coupling detection circuit CD2 is connected to the first output terminal of the RF switch SPDT and the first antenna E1. It couples the signal strength of the first antenna E1 and converts it into the second detection signal VC2. The signal VC2 is sent to the first input terminal of the second comparator circuit COM2.

[0048] The third coupling detector circuit CD3 is connected to the second output terminal of the RF switch SPDT and the second antenna E2. It couples the signal strength of the second antenna E2 and converts it into the third detector signal VC3. The signal VC3 is sent to the second input terminal of the second comparator circuit COM2.

[0049] After receiving a low-level enable signal VR, the second comparator circuit COM2 begins comparing the second detector signal VC2 and the third detector signal VC3. Based on the comparison result, it outputs a control signal VC to the RF switch SPDT. The RF switch SPDT (single-pole double-throw switch) has one stationary terminal and two moving terminals. The stationary terminal is connected to the output of the first coupling detector circuit CD1, and the two moving terminals are connected to the inputs of the second coupling detector circuit CD2 and the third coupling detector circuit CD3, respectively. According to the control signal VC, the RF switch SPDT can switch between the two moving terminals to select different antenna paths. If VC2 is greater than VC3, the RF switch SPDT switches to the first antenna E1; if VC3 is greater than VC2, it switches to the second antenna E2, thereby ensuring that the TDD source can always use the antenna with the stronger signal for communication.

[0050] In summary, this application embodiment effectively solves the dynamic antenna selection problem in TDD systems by designing an automatic antenna selection circuit that includes a radio frequency switch, multiple coupled detection circuits, and multiple comparison circuits, through hardware-level real-time signal detection and rapid switching. Furthermore, this application embodiment has the advantages of low cost and high reliability, and is applicable to various wireless communication standards, giving it significant advantages in IoT, vehicular networks, and complex wireless communication environments.

[0051] It should be noted that the embodiments described in this application are merely some embodiments, not all embodiments. The components of the embodiments of this application typically described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the above detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0052] The terms "first, second, third, etc." or similar terms such as module A, module B, module C, etc., used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that a specific order or sequence may be interchanged where permitted so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0053] In the above description, the labels indicating the steps do not necessarily mean that the steps will be executed. They may include intermediate steps or be replaced by other steps. Where permissible, the order of the steps may be interchanged or executed simultaneously.

[0054] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0055] The terms "an embodiment" or "an embodiment" as used in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of this application. Therefore, the terms "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0056] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this application, all of which fall within the scope of protection of this application.

Claims

1. An automatic antenna selection circuit based on a TDD communication system, characterized in that, It includes a radio frequency switch, multiple coupling detection circuits and multiple comparison circuits, wherein the multiple coupling detection circuits include at least a first coupling detection circuit, a second coupling detection circuit and a third coupling detection circuit, and the multiple comparison circuits include at least a first comparison circuit and a second comparison circuit. The first port of the first coupling detector circuit is connected to the TDD source, the second port is connected to the input terminal of the radio frequency switch, and the third port is connected to the first input terminal of the first comparator circuit. The first port of the second coupling detector circuit is connected to the first output terminal of the radio frequency switch, the second port is connected to the first antenna, and the third port is connected to the first input terminal of the second comparator circuit. The first port of the third coupling detector circuit is connected to the second output terminal of the radio frequency switch, the second port is connected to the second antenna, and the third port is connected to the second input terminal of the second comparator circuit. The first input terminal of the first comparator circuit receives the first detected signal output by the first coupled detector circuit, and the second input terminal receives a reference signal. The first comparator circuit outputs an enable signal to the enable terminal of the second comparator circuit according to the comparison result between the first detected signal and the reference signal, so as to control the working state of the second comparator circuit. The first input terminal of the second comparator circuit receives the second detection signal output by the second coupled detection circuit, and the second input terminal receives the third detection signal output by the third coupled detection circuit. The second comparator circuit outputs a control signal to the radio frequency switch based on the comparison result of the second detection signal and the third detection signal to control the switching of the radio frequency switch.

2. The automatic antenna selection circuit according to claim 1, characterized in that, The radio frequency switch includes a single-pole multi-throw switch. The stationary terminal of the single-pole multi-throw switch is connected to the second port of the first coupling detector circuit, the first moving terminal of the single-pole multi-throw switch is connected to the first port of the second coupling detector circuit, and the second moving terminal of the single-pole multi-throw switch is connected to the first port of the third coupling detector circuit.

3. The automatic antenna selection circuit according to claim 1, characterized in that, The coupling detection circuit includes a microstrip line coupler, a detector, and a low-pass filter; The microstrip line coupler is used to extract the received signal energy and output the coupled signal to the detector. The detector is used to convert the coupled signal into a DC level signal and output it after filtering by a low-pass filter.

4. The automatic antenna selection circuit according to claim 3, characterized in that, The detector includes a diode detector or a logarithmic detector.

5. The automatic antenna selection circuit according to claim 1, characterized in that, The comparison circuit includes a high-speed voltage comparator.

6. The automatic antenna selection circuit according to claim 1, characterized in that, The first coupling detector circuit is used to detect the state of the TDD source; When the TDD source is in the transmitting state, the first detection signal output by the first coupling detection circuit is higher than the reference signal, the first comparator circuit outputs a high-level enable signal, and the second comparator circuit does not work. When the TDD source is in the receiving state, the first detection signal output by the first coupling detection circuit is lower than the reference signal, the first comparator circuit outputs a low-level enable signal, and the second comparator circuit operates.

7. The automatic antenna selection circuit according to claim 1, characterized in that, The second coupling detection circuit is used to extract the signal strength of the first antenna and output a second detection signal, and the third coupling detection circuit is used to extract the signal strength of the second antenna and output a third detection signal; When the second comparison circuit is working, it outputs a control signal to the radio frequency switch based on the comparison result of the second detection signal and the third detection signal. The control signal is used to control the radio frequency switch to switch to the antenna with a stronger signal so that the TDD signal source can communicate through the antenna with a stronger signal.

8. A TDD communication device, characterized in that, The invention includes an automatic antenna selection circuit based on a TDD communication system as described in any one of claims 1 to 7.

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