Full-time-slot channel machine with same receiving and transmitting bandwidth

Abstract

The utility model discloses a full time slot channel machine with the same receiving and transmitting bandwidth, which comprises a radio frequency transmitting circuit, a circulator, a radio frequency receiving circuit, a tracking detection circuit and a cancellation circuit, the tracking detection circuit comprises a first sampling circuit and a second sampling circuit, and the first sampling circuit is coupled with a signal receiving circuit to generate a receiving sampling signal; the second sampling circuit is coupled with the cancellation circuit to generate a cancellation sampling signal; the cancellation circuit is connected with the tracking detection circuit and generates a cancellation radio frequency signal according to the receiving sampling signal generated by the first sampling circuit, the cancellation radio frequency signal is the same as the receiving sampling signal, and the phase difference of the cancellation radio frequency signal and the receiving sampling signal is only 180 degrees; the cancellation radio frequency signal is coupled with a portion of the signal in the receive link to cancel the portion of the signal. According to the utility model, the high-power interference on the receiving link can be offset, the risk that the receiving signal is blocked and interfered is reduced to a great extent, and the receiving link can work normally.

Description

Technical Field

[0001] This utility model relates to channel machines, and more particularly to a full-time-slot channel machine with the same transmit and receive bandwidth. Background Technology

[0002] Existing channel receivers are mainly FDD channel receivers using duplexers or TDD channel receivers using filters. However, in their receiving links, circulators cannot completely isolate reverse signals, causing some leakage. Furthermore, large signals inevitably cause some signal reflection when passing through circulators, filters, and antennas, leading to reflected signals entering the receiving link. These leakage and reflected signals, caused by the above reasons, will cause amplifier power saturation and signal distortion in the receiver's low-noise amplifier unit, worsening the noise figure of the receiving link and preventing the receiver from functioning properly. Utility Model Content

[0003] The main purpose of this invention is to provide a full-time-slot channel device with the same transmit and receive bandwidth, which can cancel high-power interference on the receiving link, greatly reduce the risk of the received signal being blocked and interfered with, and enable the receiving link to work normally.

[0004] The technical solution adopted in this utility model is:

[0005] A full-timeslot channel device with the same transmit and receive bandwidth is provided, comprising:

[0006] The radio frequency (RF) transmitting circuit generates a transmit intermediate frequency (IF) signal, mixes it with the transmit local oscillator (LO) signal, up-converts it into a transmit RF signal, and then amplifies it.

[0007] The circulator has a first port connected to the antenna and a second port connected to the radio frequency transmitting circuit. It transmits the amplified radio frequency signal through the antenna and receives external signals through the antenna.

[0008] The radio frequency receiving circuit is connected to the third port of the circulator and receives external signals through the circulator to form a signal receiving link.

[0009] The tracking and detection circuit includes a first sampling circuit and a second sampling circuit. The first sampling circuit is coupled to a signal receiving circuit to generate a received sampling signal; the second sampling circuit is coupled to a cancellation circuit to generate a cancellation sampling signal.

[0010] The cancellation circuit, connected to the tracking detection circuit, generates a cancellation radio frequency signal based on the received sampling signal generated by the first sampling circuit. This cancellation radio frequency signal is the same as the received sampling signal, only 180° out of phase. The cancellation radio frequency signal is coupled to a portion of the signal in the receiving link to eliminate that portion of the signal.

[0011] According to the above technical solution, the cancellation circuit includes a cancellation radio frequency signal generation circuit and a cancellation amplification circuit. After the cancellation radio frequency signal generation circuit generates a cancellation radio frequency signal, it is amplified by the cancellation amplification circuit. The amplified cancellation radio frequency signal is then coupled with the signal in the receiving link.

[0012] Following the above technical solution, the tracking and detection circuit also includes an RF switch to turn the first sampling circuit and the second sampling circuit on and off.

[0013] According to the above technical solution, the radio frequency receiving circuit includes multiple receiving units, and each receiving unit includes a filter, an amplifier and a receiver connected in sequence.

[0014] Following the above technical solution, the full-time-slot channel unit also includes a low-noise amplifier circuit, which is located between the radio frequency receiving circuit and the third port of the circulator.

[0015] Following the above technical solution, a protection circuit is also connected between the low-noise amplifier circuit and the third port of the circulator, and this protection circuit is also connected to the tracking detection circuit. When the first sampling circuit detects that the received sampling signal exceeds the received signal input power threshold, the protection circuit disconnects from the low-noise amplifier circuit.

[0016] According to the above technical solution, the protection circuit includes a limiting diode, a switch and a load, and the switch is connected to the load and the radio frequency receiving circuit.

[0017] Following the above technical solution, a filter is also provided between the antenna and the first port of the circulator.

[0018] The beneficial effects of this invention are as follows: By setting up a unique cancellation circuit and a tracking detection circuit, the tracking detection circuit is coupled with the signal receiving circuit to generate a received sampling signal. The cancellation circuit receives the sampling signal and generates a cancellation radio frequency signal. This cancellation radio frequency signal is the same as the received sampling signal, only 180° out of phase. It can couple with a portion of the signal in the receiving link to eliminate that portion of the signal. This portion of the signal is the high-power interference signal on the receiving link caused by leakage and reflection of the transmitted signal. It can be seen that by cancelling the interference signal in the receiving link through cancellation coupling, the influence of the interference signal generated by the transmission on the receiving link can be reduced, so that the receiver can work normally.

[0019] Furthermore, while the cancellation circuit cancels the interference signal in the receiving link, the tracking and detection circuit can sample the RF receiving link and the cancellation transmitting link in real time by switching the RF switch, thus realizing real-time tracking and detection of the two signals.

[0020] Furthermore, by setting up a protection circuit to protect the low-noise amplifier circuit, and at the same time, the tracking detection circuit can determine that an antenna port return loss alarm has occurred when it detects a high-power signal in the receiving link that exceeds the receiving signal input power threshold through the coupled receiving sampling signal. The switch is then switched to the load side to disconnect the connection with the low-noise amplifier circuit as a protection measure.

[0021] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a full-timeslot channel machine with the same transmit and receive bandwidth according to an embodiment of this utility model;

[0024] Figure 2 This is a schematic diagram of the radio frequency transmitting circuit according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the cancellation circuit according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the tracking and detection circuit according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the radio frequency receiving circuit of an embodiment of this utility model. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0029] It should be noted that the illustrations provided in the embodiments of this utility model are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0030] In this utility model, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0031] Furthermore, it should be noted that the features of the various embodiments of this utility model can be combined or integrated in part or in whole, and as those skilled in the art will understand, they can interact and operate in different ways. Each embodiment can be implemented independently of each other, or implemented in an associated relationship.

[0032] like Figure 1 As shown, the full-timeslot channel receiver with transmit and receive bandwidth in this embodiment includes an RF transmitting circuit, a circulator, an RF receiving circuit, a tracking and detection circuit, and a cancellation circuit. The RF transmitting circuit generates a transmit intermediate frequency (IF) signal, mixes it with a transmit local oscillator (LO) signal, up-converts it to a transmit RF signal, and then amplifies it. The circulator has a first port connected to an antenna and a second port connected to the RF transmitting circuit, transmitting the amplified transmit RF signal through the antenna and receiving external signals through the antenna. The RF receiving circuit is connected to the third port of the circulator, receiving external signals through the circulator to form a signal receiving link. The tracking and detection circuit includes a first sampling circuit and a second sampling circuit. The first sampling circuit is coupled to the signal receiving circuit to generate a receive sampling signal. The second sampling circuit is coupled to the cancellation circuit to generate a cancellation sampling signal. The cancellation circuit is connected to the tracking and detection circuit, generating a cancellation RF signal based on the receive sampling signal generated by the first sampling circuit. This cancellation RF signal is identical to the receive sampling signal, differing only by 180° in phase. This cancellation RF signal is coupled to a portion of the signal in the receiving link to eliminate that portion of the signal.

[0033] Furthermore, the cancellation circuit includes a cancellation radio frequency signal generation circuit and a cancellation amplification circuit. After the cancellation radio frequency signal generation circuit generates a cancellation radio frequency signal, it is amplified by the cancellation amplification circuit. The amplified cancellation radio frequency signal is then coupled with the signal in the receiving link.

[0034] Furthermore, the tracking and detection circuit also includes an RF switch to turn the first sampling circuit and the second sampling circuit on and off.

[0035] Furthermore, the full-time-slot channel unit also includes a low-noise amplifier circuit, which is located between the RF receiver circuit and the third port of the circulator.

[0036] Furthermore, a protection circuit is connected between the low-noise amplifier circuit and the third port of the circulator, and this protection circuit is also connected to the tracking detection circuit. When the first sampling circuit detects that the received sampling signal exceeds the received signal input power threshold, the protection circuit disconnects from the low-noise amplifier circuit.

[0037] In addition, a filter is provided between the antenna and the first port of the circulator.

[0038] Specifically, such as Figure 2 As shown, the RF transmitting circuit may include a transmit DAC (digital-to-analog converter), a feedback DAC, a transmit mixer, a feedback mixer, and an RF amplifier unit. The channel receiver receives the modulated carrier signal transmitted from the baseband module. The transmit DAC in the RF transmitting unit generates a transmit intermediate frequency (IF) signal, which is mixed with the transmit local oscillator and up-converted to a transmit RF signal. The transmit RF signal is transmitted to the input port of the RF amplifier unit, where it undergoes power amplification. The RF amplifier unit has functions such as RF amplification, forward and reverse sampling, status alarm, and status reporting. Through forward power sampling, the forward RF signal from the RF amplifier unit is coupled to the feedback output, mixed with the transmit local oscillator to the feedback IF, sampled by the feedback ADC, and analyzed. Digital predistortion technology can be used to achieve good linearity in the RF amplifier unit output. The linearized amplified signal is then transmitted from the output port of the RF amplifier unit through a circulator and filter before being transmitted to space by the antenna.

[0039] like Figure 3 As shown, the function of the cancellation circuit is to cancel the interference caused by the transmitted signal, enabling the device to operate without transmit / receive full-duplex intervals or transmit / receive time slot switching. Since the circulator, filter, and antenna in the RF signal transmission path are not perfect matchers, and the transmitted signal is at its rated transmit power, it is inevitable that when the antenna receives a signal transmitted by another device, there will also be a reflected signal from the transmitted signal of this channel device in the receiving link transmission path. Since this channel device has no transmit / receive full-duplex interval and no transmit / receive time slot switching, this will cause the received signal to coexist with the interference signal generated by this channel device. Because the power of the transmitted interference signal is relatively high, if this signal is not canceled, it will block and interfere with the downstream low-noise amplifier circuit, rendering the low-noise amplifier circuit inoperable and unable to perform its receiving function.

[0040] The cancellation circuit includes a cancellation DAC, a cancellation mixer, and a cancellation amplifier. The cancellation DAC generates a cancellation intermediate frequency (IF) signal, which is mixed with the transmit local oscillator to produce a cancellation radio frequency (RF) signal with the same frequency as the transmit signal. The carrier number, signal bandwidth, and frequency of the cancellation RF signal are completely identical to those of the transmit RF signal. Furthermore, the initial delay, phase, and amplitude information of the cancellation RF signal can be pre-assigned, allowing for rapid adjustment to the required values ​​during subsequent cancellation processes. The cancellation RF signal cancels out interference signals in the receiving link through cancellation coupling, reducing the impact of interference signals transmitted by the local receiver on the receiving link and ensuring the normal operation of the RF receiving circuit.

[0041] like Figure 4 As shown in the diagram, the tracking detection circuit includes an RF switch, a tracking detection mixer, and a tracking detection ADC (analog-to-digital converter). By switching the RF switch, the tracking detection ADC can acquire both the reflected signal sample and the cancellation signal sample in real time. After acquiring the two types of sampled information, the tracking detection ADC prioritizes comparing their time delay and phase, adjusting the digital domain to change the time delay and phase of the ADC output. This ensures that the time delay of the interference signal sample and the cancellation signal sample on the receiving link are equal, with a phase difference of 180°, until the interference signal in the receiving link is completely cancelled, allowing the receiving link to function normally.

[0042] The tracking and detection circuit may also include an adjustment circuit. After adjusting the time delay and phase, the digital domain will perform power adjustment to minimize the sampling power of the interference signal on the receiving link. When the interference signal power value is determined to be below the threshold required for receiving to start, the receiver (i.e., the RF receiving circuit) is deemed to meet the start-up conditions. At this time, the receiver protection switch switches from the load side to the low-noise amplifier unit, and the receiver can operate normally. The adjustment circuit maintains real-time phase detection and dynamic adjustment, ensuring that the power of the interference signal entering the low-noise amplifier is always at the minimum within a controllable range.

[0043] Radio frequency (RF) receiving circuitry may include multiple receiving units, each of which includes at least a filter, an amplifier, and a receiver connected in sequence. For example... Figure 5As shown, the RF receiving circuit includes a filter, a receiving mixer, an intermediate frequency (IF) filter, an IF amplifier, and a receiving ADC. After the receiver (i.e., the RF receiving circuit) is powered on, the signal received from the antenna is amplified by a low-noise amplifier circuit and filtered out for out-of-band interference signals by a SAW (Surface Acoustic Wave) filter. After filtering, the received signal is mixed with different local oscillators to the receiving IF frequency. Multiple receiving carrier signals are allocated to different IF receiving channels. Interference signals outside the channels are filtered out by the IF filter. The receiving IF amplifier circuit amplifies the useful received signal, which is then received by the receiving ADC within the RF receiving circuit. After processing, a high-quality received signal is obtained and demodulated by the baseband. In multi-carrier applications, the receiver can employ a superheterodyne scheme. Multiple RF signals are amplified by the receiving IF amplifier circuit via the antenna and mixed with the local oscillator signals output from multiple receiving local oscillators to output IF signals of different frequencies. After being filtered and amplified, multiple intermediate frequency (IF) signals are received by the radio frequency (RF) receiving circuit. The multiple signals are then processed by digital frequency modulation (DDC) and transmitted to the baseband for demodulation.

[0044] like Figure 1 As shown, the protection circuit may include a limiting diode, a receiver protection switch, and a load, with the receiver protection switch connected to the load and the RF receiving circuit. After the transmitter (i.e., the RF transmitting circuit) is turned on, if total reflection or abnormally large signal reflection occurs due to filter or antenna failure, the limiting diode immediately activates to protect the low-noise amplifier (LNA) circuit. Simultaneously, the tracking detection circuit detects a high-power signal in the receiving link by receiving the sampled signal, exceeding the received signal input power threshold. This indicates an antenna port return loss alarm. The receiver protection switch should be switched to the load side to disconnect the LNA circuit as protection, and an alarm message should be reported, while the output power protection device is turned off. If the tracking detection circuit detects that the interference signal level introduced by the receiving link is less than the threshold, the receiver protection switch is switched from the load side to the LNA circuit. At this time, the received signal can be received through the antenna, passing through the LNA, filter, and amplifier before entering the RF receiving circuit.

[0045] In summary, this invention employs a unique cancellation transmission unit and a tracking detection unit, which cancels out high-power interference in the receiving link caused by transmission signal leakage and reflection. This significantly reduces the risk of received signal blockage and interference, preventing the low-noise amplifier in the receiving link from power saturation due to high-power interference signals, thus avoiding deterioration of the noise figure or even malfunction. Furthermore, while the cancellation transmission link cancels interference signals in the receiving link, the tracking detection link, through tracking detection RF switch switching, performs real-time sampling of both the RF receiving link and the cancellation transmission link, achieving real-time tracking and detection of both signals.

[0046] This novel channel receiver can be applied to communication systems such as repeaters, ad hoc networks, and wireless remote repeaters. When applied in an FDD (Frequency Division Duplexing) communication system, this channel receiver scheme ensures that the receiving signal frequency and the transmitting signal frequency are within the same planned frequency bandwidth, preventing interference between the two signals. In this case, the duplex interval is no longer a fixed frequency bandwidth. When the communication device transmits one carrier with a frequency configured as Ftx1, all configurable channel frequencies other than Ftx1 within the device's bandwidth Fspan can be used as the receiving signal configuration frequency. When the communication device transmits n carriers (multi-carrier configuration, where n is the number of carriers), with carrier frequencies configured as Ftx1, Ftx2, ..., Ftxn, all configurable channel frequencies other than Ftx1, Ftx2, ..., Ftxn within the device's bandwidth Fspan can be used as the receiving signal configuration frequency.

[0047] When this channel device scheme is applied in a TDD (Time Division Duplexing) communication system, the device receives signals from multiple terminal devices. However, since the terminal devices are in bursty time slots, it cannot be guaranteed that all terminal devices are receiving or transmitting in the same time slot. Nevertheless, it is still possible to ensure that the frequency of the received signal and the frequency of the transmitted signal in the device are within the same planned frequency bandwidth, so that the transmitted signal and the received signal do not interfere with each other.

[0048] This invention enables high utilization of spectrum resources. Traditional FDD transceivers have strict duplex spacing requirements. Taking a narrowband multicarrier transceiver as an example, the receiver receives signals at frequencies F... RX1 F RX2 ...F RX n The transmitter's signal frequencies are F, ... tX1 F tX2 ...F tX n The duplex interval is F d Therefore, the frequency of the received signal and the frequency of the transmitted signal must follow the following characteristics:

[0049] F tX1 -F RX1 =|F d |

[0050] F tX2 -F RX2 =|F d |

[0051] ...

[0052] FtX2 -F RX2 =|F d |

[0053] As can be seen, in the application of traditional FDD transceivers, there is always a fixed frequency difference between the received signal frequency and the transmitted signal frequency. This limits the utilization of spectrum resources: frequencies within the duplex interval cannot be used; spectrum resources can only be used within fixed received signal bandwidth and transmitted signal bandwidth; and the received signal frequency and transmitted signal frequency are not interchangeable.

[0054] The communication system implemented using this invention, due to its unique cancelling radio frequency unit and tracking detection unit, allows the transceiver to operate without a duplexer and without a fixed duplex interval. When the received signal frequency and the transmitted signal frequency do not overlap, any frequency within the operating bandwidth can be used while maintaining good signal quality, greatly improving the utilization of frequency resources.

[0055] This invention can also support the reception of multiple TDD burst time slots. Traditional TDD transceivers have strict time slot requirements. In traditional multi-carrier TDD transceivers, in addition to the strict time slot rules for reception and transmission, multiple received signals received by the receiver must be in the same time slot, and multiple transmitted signals transmitted by the transmitter must be in the same time slot. The TDD channel unit implemented using this invention supports the reception of TDD burst time slot signals from multiple terminals. When the TDD channel unit implemented using this invention is in a transmission time slot, and simultaneously receives TDD burst time slot signals from multiple terminals, the unique cancellation transmission unit of the TDD channel unit generates a TDD cancellation radio frequency signal, which is in the same time slot as the channel unit's transmission signal. This cancels the interference caused by the transmission signal to the receiving link in that time slot. Therefore, when the receiving link receives TDD burst time slot signals from multiple terminals, the reception and transmission functions of the TDD channel unit implemented by this solution will not be affected regardless of whether the burst time slot signal is in any time slot.

[0056] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0057] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A full-timeslot channel machine with the same transmit and receive bandwidth, characterized in that, include: The radio frequency (RF) transmitting circuit generates a transmit intermediate frequency (IF) signal, mixes it with the transmit local oscillator (LO) signal, up-converts it into a transmit RF signal, and then amplifies it. The circulator has a first port connected to the antenna and a second port connected to the radio frequency transmitting circuit. It transmits the amplified radio frequency signal through the antenna and receives external signals through the antenna. The radio frequency receiving circuit is connected to the third port of the circulator and receives external signals through the circulator to form a signal receiving link. The tracking detection circuit includes a first sampling circuit and a second sampling circuit, wherein the first sampling circuit is coupled to a signal receiving circuit to generate a received sampling signal; The second sampling circuit is coupled with the cancellation circuit to generate a cancellation sampling signal; The cancellation circuit, connected to the tracking detection circuit, generates a cancellation radio frequency signal based on the received sampling signal generated by the first sampling circuit. This cancellation radio frequency signal is the same as the received sampling signal, only 180° out of phase. The cancellation radio frequency signal is coupled to a portion of the signal in the receiving link to eliminate that portion of the signal.

2. The full-timeslot channel machine with transmit and receive bandwidth according to claim 1, characterized in that, The cancellation circuit includes a cancellation radio frequency signal generation circuit and a cancellation amplification circuit. The cancellation radio frequency signal generation circuit generates a cancellation radio frequency signal, which is then amplified by the cancellation amplification circuit. The amplified cancellation radio frequency signal is then coupled with the signal in the receiving link.

3. The full-timeslot channel machine with the same transmit and receive bandwidth according to claim 1, characterized in that, The tracking detection circuit also includes an RF switch to turn the first sampling circuit and the second sampling circuit on and off.

4. The full-timeslot channel machine with the same transmit and receive bandwidth according to claim 1, characterized in that, The radio frequency receiving circuit includes multiple receiving units, each of which includes a filter, an amplifier, and a receiver connected in sequence.

5. The full-timeslot channel machine with transmit and receive bandwidth according to claim 1, characterized in that, The full-time-slot channel unit also includes a low-noise amplifier circuit, which is located between the RF receiver circuit and the third port of the circulator.

6. The full-timeslot channel machine with transmit and receive bandwidth according to claim 5, characterized in that, A protection circuit is also connected between the low-noise amplifier circuit and the third port of the circulator, and this protection circuit is also connected to the tracking detection circuit. When the first sampling circuit detects that the received sampling signal exceeds the received signal input power threshold, the protection circuit disconnects from the low-noise amplifier circuit.

7. The full-timeslot channel machine with transmit and receive bandwidth according to claim 6, characterized in that, The protection circuit includes a limiting diode, a switch, and a load, with the switch connecting the load and the RF receiving circuit.

8. The full-timeslot channel machine with the same transmit and receive bandwidth according to claim 1, characterized in that, A filter is also provided between the antenna and the first port of the circulator.

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