TDD Wireless
The TDD radio stabilizes gain fluctuations by using temperature-compensated bias voltage and gain adjustments, ensuring consistent performance and high communication quality in sub-millimeter and millimeter wave bands.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KOKUSAI DENKI ELECTRIC INC
- Filing Date
- 2024-11-12
- Publication Date
- 2026-05-22
AI Technical Summary
Conventional TDD wireless devices using the sub-millimeter wave or millimeter wave band face significant gain fluctuations due to temperature changes, leading to inappropriate bias voltage and gain corrections, which disrupt orthogonality of subcarriers and deteriorate EVM (Error Vector Magnitude) during transmission and reception.
The TDD radio incorporates temperature sensors to detect fluctuations and adjusts bias voltage and gain settings for both transmission and reception systems at the start of each operation section, using correction values stored in temperature compensation tables to maintain consistent settings throughout.
This approach stabilizes transmission and reception gains, preventing deviations within OFDM symbols and ensuring high communication quality by minimizing EVM degradation.
Smart Images
Figure 2026084773000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a TDD (Time Division Duplex) radio, and more particularly to a TDD radio that can achieve high communication quality when using the quasi-millimeter wave band or the millimeter wave band.
Background Art
[0002] [Prior Art] In 5GNR (5th Generation New Radio) and FWA (Fixed Wireless Access) systems that use the quasi-millimeter wave band (for example, 22 to 30 GHz band) or the millimeter wave band (for example, 30 to 40 GHz band), as a radio, a TDD (Time Division Duplex) radio using the TDD method is used to improve the frequency utilization efficiency, and as a modulation method, OFDM (Orthogonal Frequency Division Multiplexing) is used to improve high-speed data transmission and interference resistance characteristics.
[0003] In the future, in 5GNR and FWA, with the increase in the number of values for realizing further high-speed and large-capacity, it is necessary to tighten the EVM (Error Vector Magnitude: modulation accuracy) standard in order to improve communication quality.
[0004] [Configuration of Conventional TDD Radio: FIG. 3] The configuration of a conventional TDD radio will be described with reference to FIG. 3. FIG. 3 is an explanatory diagram showing the configuration of a conventional TDD radio. As shown in FIG. 3, a conventional TDD radio (conventional radio) includes a signal processing unit 31, a transmission DA converter 32, a transmission IF unit (TXIF) 33, a transmission frequency converter 34, a transmission RF unit (TXRF) 35, a transmit / receive switch 36, an antenna 37, a receive RF unit (RXRF) 38, a receive frequency converter 39, a receive IF unit (RXIF) 40, and a receive AD converter 41.
[0005] The signal processing unit 31 performs various signal processing operations such as encoding / decoding, digital modulation / demodulation, and error correction associated with the transmission and reception of digital signals. Furthermore, the signal processing unit 31 outputs a control signal (TDD signal) that switches between transmitting and receiving based on the TDD timing, and switches the transmit / receive switch 37 to transmit or receive. Furthermore, the signal processing unit 31 monitors the transmitted power and controls (corrects) the bias voltage and transmitted gain of the transmitting system, and monitors the received power and controls (corrects) the bias voltage and received gain of the receiving system. This will be described later.
[0006] The DA converter 32 for transmission converts the digital transmission signal into an analog transmission signal. The transmitting IF section 33 attenuates noise from the analog transmission signal from the transmitting DA converter 32 and amplifies it. The transmission frequency converter 34 converts the analog transmission signal from the transmission IF unit 33 into a transmission frequency. The transmitting RF unit 35 filters the analog transmission signal output from the transmitting frequency converter 34 to reduce spurious emissions, amplifies the signal, and outputs it to the transmit / receive selector switch 36.
[0007] The transmit / receive switch 36 switches between transmit and receive based on a control signal from the signal processing unit 31. When transmitting, the transmitting RF unit 35 is connected to the antenna 37, and when receiving, the receiving RF unit 38 is connected to the antenna 37. Antenna 37 radiates the RF signal from the transmit / receive switch 36 into the air during transmission, and captures the RF signal and outputs it to the transmit / receive switch 36 during reception.
[0008] The receiving RF section 38 amplifies and filters the analog received signal from the transmit / receive selector switch 36 using a low-noise amplifier (LNA). The receiving frequency converter 39 converts the analog received signal into an IF signal. The receiving IF section 40 filters the IF signal from the receiving frequency converter 39 to reduce spurious emissions and then amplifies it. The receiving AD converter 41 converts the analog received signal from the receiving IF unit 40 into a digital received signal and outputs it to the signal processing unit 31.
[0009] [Operation of a conventional wireless device: Figure 3] The transmission data is processed by the signal processing unit 31 to generate a transmission signal, which is then converted into an analog transmission signal by the transmission DA converter 32, and finally converted into an IF signal by the transmission IF unit 33. Then, the signal is converted to a transmission frequency by the transmission frequency converter 34, amplified to a predetermined power level by the transmission RF unit 35, and transmitted from the antenna 37 when the transmit / receive switch 36 is switched to the transmit side.
[0010] Furthermore, the analog received signal input from antenna 37 is output to the receiving RF section 38 when the transmit / receive switch 36 is switched to the receive side, where it is amplified, filtered, and then converted into an IF signal by the receiving frequency converter 39. The signal is then amplified in the receiving IF section, converted into a digital received signal by the receiving AD converter, and processed by the signal processing unit 31 to output the received data.
[0011] Furthermore, in order to reduce power consumption and prevent transmission power from interfering into the receiving system, the signal processing unit 31 is equipped with a bias circuit that controls the on / off of the bias voltage in conjunction with the TDD signal. During transmission, the power supply voltage to the devices of the transmission system 42 (transmission IF unit 33, transmission frequency converter 34, transmission RF unit 35) is turned ON, and the devices of the receiving system 43 (receiving RF unit 38, receiving frequency converter 39, receiving IF unit 40) are turned OFF. On the other hand, during reception, the system is controlled to turn on the receiving system 43 and turn off the transmitting system 42.
[0012] [Conventional bias voltage and gain correction: Figures 3, 4] The correction of bias voltage and gain in conventional radio transceivers will be explained using Figures 3 and 4. Figure 4 is an explanatory diagram showing the gain fluctuations in a conventional radio transceiver, where (a) shows the change in transmitted power and (b) shows the change in received power. In radio equipment using the sub-millimeter wave or millimeter wave band, the gain fluctuation due to temperature is larger compared to radio equipment using lower frequencies, so the signal processing unit 31 performs gain correction and bias voltage correction for the transmission system 42 and the reception system 43, respectively.
[0013] Specifically, the signal processing unit 31 corrects the bias voltage of the transmission system 42 and the transmission gain in the amplification circuit based on fluctuations in the transmission power, and corrects the bias voltage of the receiving system 43 and the reception gain based on fluctuations in the reception power.
[0014] However, due to the large range of gain fluctuations caused by temperature, it is difficult to properly control the bias voltage and gain by the signal processing unit 31. Furthermore, because the timing of correction is not fixed, correction may be performed in the middle of the TDD transmission section, changing the gain of the transmission system 32, or the gain of the receiving system 43 may be changed in the middle of the TDD reception section.
[0015] For example, in the example shown in Figure 4(a), when the signal processing unit 31 detects a sudden drop in received power at time t1, it corrects by increasing the bias voltage and gain of the transmission system 42. However, the increase is greater than the optimal amount, and even in the middle of the transmission section, the transmitted power increases after time t1. Furthermore, in the correction at time t3, the increase is smaller than the optimal amount, resulting in lower transmission power within the same transmission section compared to before time t3.
[0016] Furthermore, as shown in Figure 4(b), if the bias voltage and gain are also corrected for the received power, a change in the received power occurs within the same reception interval, with the corrections at time t2 and time t4 being the dividing lines.
[0017] Thus, conventionally, the signal processing unit 31 controlled the bias voltage and gain at random timings regardless of the transmission / reception operation of the TDD, which sometimes caused the gain to fluctuate in the middle of the transmission or reception section. When a gain deviation occurs within an OFDM symbol due to fluctuations in gain during the transmission / reception interval, the orthogonality of subcarriers is disrupted, leading to deterioration of EVM.
[0018] [Related Art] As a related prior art, there is Japanese Patent Application Laid-Open No. 2008-167500, "Transmission Power Control Method and Wireless Access System" (Patent Document 1). Patent Document 1 discloses a wireless access system that reduces the burden on a base station on the telecommunications carrier side by calculating an optimal transmission power on the subscriber base station side in a system including a plurality of subscriber base stations. [Prior Art Documents] [Patent Documents]
[0019] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-167500 [Summary of the Invention] [Problems to be Solved by the Invention]
[0020] As described above, conventional TDD wireless devices using the sub-millimeter wave band or millimeter wave band have a problem that the gain fluctuates greatly due to temperature changes, and it is difficult to appropriately correct the gain and bias voltage.
[0021] Also, in conventional TDD wireless devices, since the correction of the bias voltage and gain is performed at random timings, the bias voltage and gain change during the transmission interval or reception interval, and a gain deviation occurs within the OFDM symbol, disrupting the orthogonality of subcarriers and sometimes deteriorating the EVM.
[0022] Furthermore, Patent Document 1 does not describe a configuration in which the bias voltage and gain corresponding to temperature are set at the start of the transmission / reception interval by TDD.
[0023] This invention has been made in view of the above circumstances, and aims to provide a TDD radio that can set appropriate bias voltage and gain according to temperature, maintain a constant bias voltage and gain within each transmission / reception section, prevent EVM degradation by preventing gain deviation within OFDM symbols, and achieve high communication quality. [Means for solving the problem]
[0024] To solve the problems of the above-mentioned conventional example, the present invention is characterized in that, in a TDD radio, it comprises: a transmit / receive selector switch connected to an antenna; a signal processing unit that controls the transmit / receive selector switch and outputs a digital transmit signal and inputs a digital receive signal; a DA converter that converts the digital transmit signal into an analog transmit signal; a transmit IF unit that attenuates noise and amplifies the analog transmit signal output from the DA converter; a transmit frequency converter that converts the analog transmit signal output from the transmit IF unit into a transmit frequency; a transmit RF unit that reduces spurious emissions from the analog transmit signal output from the transmit frequency converter, amplifies it, and outputs it to the transmit / receive selector switch; a transmit temperature correction setting and holding unit that outputs a transmit correction value corresponding to the temperature detected by a temperature sensor; and a transmit bias / gain setting circuit that corrects and sets the transmit bias voltage and amplification gain for the transmit IF unit, transmit frequency converter, and transmit RF unit using the transmit correction value from the transmit temperature correction setting and holding unit.
[0025] Furthermore, the present invention is characterized in that the above-mentioned TDD radio includes a receiving RF section that amplifies the analog received signal from the transmit / receive switching switch, a receiving frequency converter that converts the analog received signal from the receiving RF section into an IF signal, a receiving IF section that attenuates the spurious signals of the analog received signal from the receiving frequency converter and amplifies it, an AD converter that converts the analog received signal from the receiving IF section into a digital received signal and outputs it to a signal processing unit, a receiving temperature correction setting and holding section that outputs a receiving correction value corresponding to the temperature detected by a temperature sensor, and a receiving bias / gain setting circuit that corrects and sets the receiving bias voltage and amplification gain for the receiving RF section, the receiving frequency converter, and the receiving IF section using the receiving correction value from the receiving temperature correction setting and holding section.
[0026] Furthermore, the present invention is characterized in that, in the above-mentioned TDD radio, the signal processing unit turns off the power to the transmitting IF unit, transmitting frequency converter, and transmitting RF unit during the receiving operation section, the transmitting temperature correction setting holding unit identifies the transmitting correction value for the next transmitting operation section during the receiving operation section, the transmitting bias / gain setting circuit corrects the transmitting bias voltage and amplification gain with the transmitting correction value from the transmitting temperature correction setting holding unit at the start of the next transmitting operation section, sets the corrected transmitting bias voltage and amplification gain to the transmitting IF unit, transmitting frequency converter, and transmitting RF unit, and when the transmitting bias voltage and amplification gain are set, the transmitting IF unit, transmitting frequency converter, and transmitting RF unit operate with the set transmitting bias voltage and amplification gain during the transmitting operation section.
[0027] Furthermore, the present invention is characterized in that, in the above-mentioned TDD radio, the signal processing unit turns off the power to the receiving RF unit, receiving frequency converter, and receiving IF unit during the transmission operation section; the receiving temperature correction setting holding unit identifies the receiving correction value for the next receiving operation section during the transmission operation section; the receiving bias / gain setting circuit corrects the receiving bias voltage and amplification gain using the receiving correction value from the receiving temperature correction setting holding unit at the start of the next receiving operation section, sets the corrected receiving bias voltage and amplification gain to the receiving IF unit, receiving frequency converter, and receiving RF unit; and once the receiving bias voltage and amplification gain are set, the receiving IF unit, receiving frequency converter, and receiving RF unit operate with the set receiving bias voltage and amplification gain during the receiving operation section.
[0028] Furthermore, the present invention is characterized in that, in the above-mentioned TDD radio, the transmitting temperature correction setting holding unit and the receiving temperature correction setting holding unit output a transmitting correction value or a receiving correction value that lowers the transmitting bias voltage and the receiving bias voltage and increases the amplification gain when the temperature from the temperature sensor rises, and outputs a transmitting correction value or a receiving correction value that raises the transmitting bias voltage and the receiving bias voltage and decreases the amplification gain when the temperature from the temperature sensor falls.
[0029] Furthermore, the present invention is characterized in that, in the above-mentioned TDD radio, the transmitting temperature correction setting holding unit includes a transmitting table that stores a transmitting correction value for temperature, reads a transmitting correction value corresponding to the temperature detected by the temperature sensor from the transmitting table and outputs it to the transmitting bias / gain setting circuit, and the receiving temperature correction setting holding unit includes a receiving table that stores a receiving correction value for temperature, reads a receiving correction value corresponding to the temperature detected by the temperature sensor from the receiving table and outputs it to the receiving bias / gain setting circuit. [Effects of the Invention]
[0030] According to the present invention, a TDD radio includes a transmit / receive selector switch connected to an antenna, a signal processing unit that controls the transmit / receive selector switch and outputs a digital transmission signal and inputs a digital reception signal, a DA converter that converts the digital transmission signal into an analog transmission signal, a transmitting IF unit that attenuates noise and amplifies the analog transmission signal output from the DA converter, a transmitting frequency converter that converts the analog transmission signal output from the transmitting IF unit into a transmission frequency, a transmitting RF unit that reduces spurious emissions from the analog transmission signal output from the transmitting frequency converter, amplifies it, and outputs it to the transmit / receive selector switch, a transmitting temperature correction setting and holding unit that outputs a transmitting correction value corresponding to the temperature detected by a temperature sensor, and a transmitting bias / gain setting circuit that corrects and sets the transmitting bias voltage and amplification gain for the transmitting IF unit, transmitting frequency converter, and transmitting RF unit using the transmitting correction value from the transmitting temperature correction setting and holding unit. As such, even if the temperature fluctuates, an appropriate transmitting bias voltage and amplification gain can be set for the transmitting system devices according to the temperature, which has the effect of suppressing fluctuations in transmission power and achieving good communication quality.
[0031] Furthermore, according to the present invention, the TDD radio includes a receiving RF section that amplifies the analog received signal from the transmit / receive switching switch, a receiving frequency converter that converts the analog received signal from the receiving RF section into an IF signal, a receiving IF section that attenuates spurious signals from the receiving frequency converter and amplifies them, an AD converter that converts the analog received signal from the receiving IF section into a digital received signal and outputs it to a signal processing unit, a receiving temperature correction setting and holding section that outputs a receiving correction value corresponding to the temperature detected by a temperature sensor, and a receiving bias / gain setting circuit that corrects and sets the receiving bias voltage and amplification gain for the receiving RF section, receiving frequency converter, and receiving IF section using the receiving correction value from the receiving temperature correction setting and holding section. As a result, the receiving system devices can also be set with appropriate receiving bias voltage and amplification gain according to the temperature, which has the effect of suppressing fluctuations in received power and achieving good communication quality.
[0032] Furthermore, according to the present invention, the signal processing unit turns off the power to the transmitting IF unit, transmitting frequency converter, and transmitting RF unit during the receiving operation section, the transmitting temperature correction setting holding unit identifies the transmitting correction value for the next transmitting operation section during the receiving operation section, the transmitting bias / gain setting circuit corrects the transmitting bias voltage and amplification gain using the transmitting correction value from the transmitting temperature correction setting holding unit at the start of the next transmitting operation section, sets the corrected transmitting bias voltage and amplification gain to the transmitting IF unit, transmitting frequency converter, and transmitting RF unit, and when the transmitting bias voltage and amplification gain are set, the transmitting IF unit, transmitting frequency converter, and transmitting RF unit operate with the set transmitting bias voltage and amplification gain during the transmitting operation section. As described above, the TDD radio enables fine-tuned adjustment by identifying an appropriate transmitting correction value according to the temperature for each receiving operation section, and because the transmitting bias voltage and amplification gain do not fluctuate in the middle of the transmitting operation section, gain deviations within OFDM symbols do not occur, preventing EVM degradation and achieving good communication quality.
[0033] Furthermore, according to the present invention, the signal processing unit turns off the power to the receiving RF unit, receiving frequency converter, and receiving IF unit during the transmission operation section, the receiving temperature correction setting holding unit identifies the receiving correction value for the next receiving operation section during the transmission operation section, the receiving bias / gain setting circuit corrects the receiving bias voltage and amplification gain using the receiving correction value from the receiving temperature correction setting holding unit at the start of the next receiving operation section, sets the corrected receiving bias voltage and amplification gain to the receiving IF unit, receiving frequency converter, and receiving RF unit, and when the receiving bias voltage and amplification gain are set, the receiving IF unit, receiving frequency converter, and receiving RF unit operate with the set receiving bias voltage and amplification gain during the receiving operation section. As described above, the TDD radio is configured such that, by identifying an appropriate transmission correction value according to the temperature for each transmission operation section, fine adjustment is possible, and since the receiving bias voltage and amplification gain do not fluctuate in the middle of the receiving operation section, gain deviations in OFDM symbols do not occur, preventing EVM degradation and achieving good communication quality. [Brief explanation of the drawing]
[0034] [Figure 1] This is an explanatory diagram showing the configuration of this radio. [Figure 2] This is an explanatory diagram showing the gain characteristics of this radio. [Figure 3] This is an explanatory diagram showing the configuration of a conventional TDD radio. [Figure 4] This is an explanatory diagram showing the gain fluctuations in a conventional radio. [Modes for carrying out the invention]
[0035] Embodiments of the present invention will be described with reference to the drawings. [Summary of the Embodiment] The TDD radio according to an embodiment of the present invention (this radio) comprises a transmission temperature correction setting and holding unit that outputs a transmission correction value corresponding to the temperature detected by a temperature sensor, and a transmission bias / gain setting circuit that corrects and sets the transmission bias voltage and amplification gain for the transmission device using the transmission correction value from the transmission temperature correction setting and holding unit. The transmission temperature correction setting and holding unit identifies the transmission correction value for the next transmission operation section during the reception operation section of the TDD, and the transmission bias / gain setting circuit corrects the transmission bias voltage and amplification gain using the transmission correction value from the transmission temperature correction setting and holding unit at the start of the next transmission operation section, setting the corrected transmission bias voltage and amplification gain for the transmission device. Once the transmission bias voltage and amplification gain are set, the transmission device operates in the transmission operation section while maintaining the set transmission bias voltage and amplification gain. This enables the setting of an appropriate transmission bias voltage and amplification gain based on temperature, prevents the transmission bias voltage and amplification gain from being changed in the middle of the transmission operation section, prevents gain deviation within OFDM symbols, prevents EVM degradation, and achieves high communication quality.
[0036] Furthermore, this radio includes, in the above-mentioned TDD radio, a receiving temperature correction setting holding unit that outputs a receiving correction value corresponding to the temperature detected by a temperature sensor, and a receiving bias / gain setting circuit that corrects and sets the receiving bias voltage and amplification gain for the receiving device using the receiving correction value from the receiving temperature correction setting holding unit. The receiving temperature correction setting holding unit identifies the receiving correction value for the next receiving operation section during the transmission operation section of the TDD, and the receiving bias / gain setting circuit corrects the receiving bias voltage and amplification gain using the receiving correction value from the receiving temperature correction setting holding unit at the start of the next receiving operation section, setting the corrected receiving bias voltage and amplification gain for the receiving device. Once the receiving bias voltage and amplification gain are set, the receiving device operates while maintaining the set receiving bias voltage and amplification gain for that receiving operation section. This allows for setting an appropriate receiving bias voltage and amplification gain based on temperature, prevents the receiving bias voltage and amplification gain from being changed in the middle of a receiving operation section, prevents gain deviation within OFDM symbols, prevents EVM degradation, and achieves high communication quality.
[0037] [Configuration of this radio: Figure 1] The configuration of this radio will be explained using Figure 1. Figure 1 is an explanatory diagram showing the configuration of this radio. As shown in Figure 1, this radio unit includes a signal processing unit 11, a transmitting DA converter 12, a transmitting IF unit (TXIF) 13, a transmitting frequency converter 14, a transmitting RF unit (TXRF) 15, a transmit / receive switch 16, an antenna 17, a receiving RF unit (RXRF) 18, a receiving frequency converter 19, a receiving IF unit (RXIF) 20, and a receiving AD converter 21, as configured in conventional radio units. Of these components, the parts other than the signal processing unit 11 are the same as in the conventional design, and therefore their explanation will be omitted. The signal processing unit 11 operates differently from conventional units in some respects, which will be described later.
[0038] Furthermore, this wireless device includes, as a new configuration, temperature sensors 22 and 25, a transmission temperature compensation setting and holding unit 23, a transmission bias and gain setting circuit 24, a reception temperature compensation setting and holding unit 26, and a reception bias and gain setting circuit 27.
[0039] This section explains the distinctive features of this radio. [Signal Processing Unit 11] The signal processing unit 11 outputs signal processing associated with transmission and reception, as in the conventional system, and a TDD signal for switching between transmission and reception. In this embodiment, the TDD signal indicating the transmission section is referred to as the transmission TDD signal, and the TDD signal indicating the reception section is referred to as the reception TDD signal. The transmit TDD signal is a signal that indicates the transmission period; the transmission period is when the transmit TDD signal is ON. The received TDD signal is a signal that indicates the reception period, and the reception period is when the received TDD signal is ON.
[0040] In this radio, the transmitted TDD signal is input not only to the conventional transmit / receive selector switch 16, but also to the transmit bias / gain setting circuit 24 and the receive temperature compensation setting circuit 26, which will be described later. Furthermore, the received TDD signal is input to the transmission temperature compensation setting holding unit 23 and the reception bias / gain setting circuit 27, which will be described later. As a result, the transmission temperature compensation setting holding unit 23 and the reception bias / gain setting circuit 27 operate during the reception section, while the transmission bias / gain setting circuit 24 and the reception temperature compensation setting circuit 26 operate during the transmission section.
[0041] Furthermore, while conventional radios had a signal processing unit 31 that controlled the bias voltage and amplification gain for the transmission and reception systems, the signal processing unit 11 of this radio does not control the bias voltage and gain.
[0042] [Temperature sensors 22, 25] The temperature sensor 22 detects the temperature near the transmitting device (transmitting device) inside the radio and outputs the temperature information to the transmitting temperature correction setting holding unit 23. The transmitting device consists of a transmitting IF unit (TXIF) 13, a transmitting frequency converter 14, and a transmitting RF unit (TXRF) 15.
[0043] Furthermore, the temperature sensor 25 detects the temperature near the receiving system device (receiving device) inside the radio and outputs the temperature information to the receiving temperature correction setting holding unit 26. The receiving device consists of a receiving RF unit (RXRF) 18, a receiving frequency converter 19, and a receiving IF unit (RXIF) 20.
[0044] Although two temperature sensors are provided here, it is also possible to use only one and configure it to output the detected temperature information to both the transmitting temperature correction setting holding unit 23 and the receiving temperature correction setting holding unit 26. Furthermore, since the gain fluctuation due to temperature is greater in the transmission system, if only one temperature sensor is used, it is desirable to use temperature sensor 22, which is installed near the transmission system.
[0045] [Temperature correction setting holding unit 23 for transmission] The transmission temperature correction setting and holding unit 23 receives the TDD signal from the signal processing unit 11 and the temperature information from the temperature sensor 22, and identifies and holds the correction values (transmission correction values) for the transmission bias voltage and transmission gain according to the temperature during the reception period. Specifically, the transmission temperature compensation setting and holding unit 23 includes a transmission temperature compensation table that stores appropriate bias voltages for the transmission devices (transmission IF unit 13, transmission frequency converter 14, transmission RF unit 15) and appropriate transmission gain values for the amplifier, corresponding to multiple temperature information.
[0046] Then, when the TDD signal received from the signal processing unit 11 is turned on, the transmission temperature correction setting holding unit 23 reads the bias voltage and transmission gain corresponding to the temperature information from the temperature sensor 22 from the transmission temperature correction table and holds them as transmission correction values. In other words, the transmission temperature correction setting and holding unit 23 identifies appropriate transmission bias voltage and transmission gain according to the temperature inside the radio at the beginning of the receiving section and holds them as transmission correction values for the next transmission section.
[0047] The transmit temperature compensation table stores values where the transmit bias voltage is lower (smaller) and the transmit gain is higher (larger) as the temperature increases. As a result, the transmitting device is controlled to lower the transmit bias voltage and increase the transmit gain when the temperature rises. Furthermore, the "correction values (transmission correction value, reception correction value)" described in this embodiment and the claims do not specify a range of variation from the current value such as the transmission bias voltage, but rather indicate a value that overwrites (updates) the current value.
[0048] Furthermore, in this embodiment, the transmit temperature compensation table stores the transmit bias voltage and transmit gain common to the transmit device, but it is also possible to store these values separately for the transmit IF unit 13, the transmit frequency converter 14, and the transmit RF unit 15.
[0049] [Transmit bias / gain setting circuit 24] The transmit bias / gain setting circuit 24 reads the transmit correction value held by the transmit temperature correction setting holding unit 23 based on the transmit TDD signal, and sets the transmit correction value for the transmit IF unit 13, the transmit frequency converter 14, and the transmit RF unit 15.
[0050] Specifically, when the transmit TDD signal is turned on, the transmit bias / gain setting circuit 24 reads the transmit correction value, including the transmit bias voltage and transmit gain to be newly set, from the transmit temperature correction setting holding unit 23, and sets the transmit bias voltage to the transmit IF unit 13, the transmit frequency converter 14, and the transmit RF unit 15, and sets the transmit gain to the transmit IF unit 13 and the transmit RF unit 15. In other words, the transmit bias / gain setting circuit 24 sets the transmit bias voltage and transmit gain, which have been corrected according to the temperature, to the transmit device at the moment the transmit device is turned on (at the beginning of the transmit section).
[0051] Then, when the transmitting device (transmitting IF unit 13, transmitting frequency converter 14, transmitting RF unit 15) sets the transmitting bias voltage and transmitting gain at the beginning of the transmission section, it maintains the set transmitting bias voltage and transmitting gain throughout the transmission section and operates without changing them midway through. This prevents fluctuations in the transmission system's gain during the transmission section, thus preventing gain deviations within the symbol.
[0052] [Reception temperature correction setting holding unit 26] The receiving temperature correction setting and holding unit 26 includes a receiving temperature correction table that stores appropriate bias voltages for the receiving devices (receiving RF unit 18, receiving frequency conversion unit 19, receiving IF unit 20) and appropriate receiving gain values for the amplifier. Based on the transmitted TDD signal and temperature information from the temperature sensor 25, it identifies and holds correction values (receiving correction values) for the receiving bias voltage and receiving gain according to the temperature during the transmission section.
[0053] When the transmission TDD signal from the signal processing unit 11 is turned on, the receiving temperature correction setting holding unit 26 reads the bias voltage and receiving gain corresponding to the temperature information from the temperature sensor 25 from the receiving temperature correction table at the beginning of the transmission section and holds them as receiving correction values for the next reception section. The receiver temperature compensation table stores values where the receiver bias voltage is lower and the receiver gain is higher as the temperature increases. As a result, the receiver device is controlled to lower the receiver bias voltage and increase the receiver gain when the temperature rises.
[0054] Furthermore, although the receiving temperature compensation table here stores the common receiving bias voltage and receiving gain for the receiving device, these may also be stored for each of the receiving RF section 18, the receiving frequency conversion section 19, and the receiving IF section 20.
[0055] [Receiver bias / gain setting circuit 27] The receiving bias / gain setting circuit 27 reads the receiving correction value from the receiving temperature correction setting holding unit 26 based on the received TDD signal, and sets the receiving correction value in the receiving RF unit 18, the receiving frequency conversion unit 19, and the receiving IF unit 20. When the received TDD signal is turned on, the receiving bias / gain setting circuit 27 reads the receiving correction value from the receiving temperature correction setting holding unit 26 at the beginning of the receiving section, sets the receiving bias voltage to the receiving RF unit 18, the receiving frequency conversion unit 19, and the receiving IF unit 20, and sets the receiving gain to the receiving RF unit 18 and the receiving IF unit 20.
[0056] Then, when the receiving device (receiving RF section 18, receiving frequency converter 19, receiving IF section 20) sets the receiving bias voltage and receiving gain at the beginning of the receiving section, it operates while maintaining the set receiving bias voltage and receiving gain throughout that receiving section. This prevents fluctuations in the gain of the receiving system during the receiving section.
[0057] [Operation of bias voltage and gain control in this radio: Figure 1] Next, the operation of the bias voltage and gain control in this radio will be explained. In the transmission system, when the received TDD signal is turned on, the transmission temperature correction setting holding unit 23 identifies and holds a transmission correction value, including the transmission bias and transmission gain, corresponding to the temperature information from the temperature sensor 22. Then, when the transmit TDD signal is turned on instead of the receive TDD signal, the transmit bias / gain setting circuit 24 reads the transmit correction value from the transmit temperature correction setting holding unit 23 and sets it for the transmit device.
[0058] Then, when the next received TDD signal is turned on, the transmission temperature correction setting holding unit 23 reads new temperature information and identifies the corresponding transmission correction value. In other words, this radio detects the temperature for each receiving section, identifies the appropriate transmission bias voltage and transmission gain accordingly, and sets them in the transmitting device at the beginning of the next transmission section. This allows for fine-tuning and reliable communication even with temperature fluctuations.
[0059] In the receiving system, when the transmitting TDD signal is turned on, the receiving temperature correction setting holding unit 26 identifies and holds a receiving correction value, including the receiving bias voltage and receiving gain, corresponding to the temperature information from the temperature sensor 25. When the receiving TDD signal is turned on, the receiving bias / gain setting circuit 27 reads the receiving correction value and sets it for the receiving device.
[0060] As a result, this radio detects the temperature for each transmission section, identifies the appropriate receiving bias voltage and receiving gain accordingly, and sets them in the receiving device at the beginning of the next receiving section. This enables fine-tuned adjustment in response to temperature fluctuations, thereby achieving good communication.
[0061] [Gain characteristics of this radio: Figure 2] The gain characteristics of this radio will be explained using Figure 2. Figure 2 is an explanatory diagram showing the gain characteristics of this radio, where (a) shows the change in transmitted power and (b) shows the change in received power. Figure 2(a) shows two transmission intervals, from time t1 to time t2 and from time t3 to time t4. No gain fluctuations are observed within either transmission interval. This prevents gain deviations from occurring in the middle of the OFDM symbol, enabling good communication quality without degrading the EVM.
[0062] Furthermore, comparing the transmission power in transmission sections (t1-t2) and (t3-t4), the transmission power in transmission section (t3-t4) is slightly lower. This is because, during the reception interval from time t2 to t3, the transmission power changed due to the control of the bias voltage and transmission gain according to the temperature.
[0063] Similarly, in Figure 2(b), no fluctuations in received power occurred within either the receiving section (t2~t3) or the receiving section (t4~t5). This prevents EVM degradation due to gain deviations in the middle of the OFDM symbol, enabling good communication quality.
[0064] [Effects of the embodiment] This radio includes a transmission temperature correction setting and holding unit 23 that outputs a transmission correction value corresponding to the temperature detected by the temperature sensor 22, and a transmission bias / gain setting circuit 24 that corrects and sets the transmission bias voltage and amplification gain for the transmission device (transmission IF unit 13, transmission frequency converter 14, transmission RF unit 15) using the transmission correction value from the transmission temperature correction setting and holding unit 23. The transmission temperature correction setting and holding unit 23 identifies the transmission correction value for the next transmission operation section during the reception operation section of the TDD, and the transmission bias / gain setting circuit 24, at the start of the next transmission operation section, uses the transmission correction value from the transmission temperature correction setting and holding unit 23. The transmit bias voltage and amplification gain are corrected, and the corrected transmit bias voltage and amplification gain are set for the transmitting device. Once the transmit bias voltage and amplification gain are set, the transmitting device operates as a TDD radio, maintaining the set transmit bias voltage and amplification gain for the transmission operation section. This allows for setting appropriate transmit bias voltage and amplification gain according to the temperature inside the radio, prevents the transmit bias voltage and amplification gain from being changed in the middle of the transmission operation section, prevents gain deviation within OFDM symbols, prevents EVM degradation, and achieves high communication quality.
[0065] Furthermore, this radio includes a receiving temperature correction setting holding unit 26 that outputs a receiving correction value corresponding to the temperature detected by the temperature sensor 25, and a receiving bias / gain setting circuit 27 that corrects and sets the receiving bias voltage and amplification gain for the receiving device (receiving RF unit 18, receiving frequency converter 19, receiving IF unit 20) using the receiving correction value from the receiving temperature correction setting holding unit 26. The receiving temperature correction setting holding unit 26 identifies the receiving correction value for the next receiving operation section during the transmission operation section of the TDD, and the receiving bias / gain setting circuit 27, at the start of the next receiving operation section, uses the receiving correction value from the receiving temperature correction setting holding unit 26. By correcting the receive bias voltage and amplification gain based on positive values, the TDD radio sets the corrected receive bias voltage and amplification gain to the receiving device. Once the receive bias voltage and amplification gain are set, the receiving device maintains the set receive bias voltage and amplification gain for the receiving operation section. This allows for setting appropriate receive bias voltage and amplification gain according to temperature to the receiving device, prevents changes in the receive bias voltage and amplification gain during the receiving operation section, prevents gain deviation within OFDM symbols, prevents EVM degradation, and achieves high communication quality. [Industrial applicability]
[0066] The present invention is suitable for TDD radio transceivers that can set appropriate bias voltage and gain according to temperature when using the quasi-millimeter wave band or millimeter wave band, and maintain a constant bias voltage and gain within each transmission / reception section, thereby achieving high communication quality. [Explanation of symbols]
[0067] 11,31…Signal processing unit, 12,32…Transmitting DA converter, 13,33…Transmitting IF unit, 14,34…Transmitting frequency converter, 15,35…Transmitting RF unit, 16,36…Transmit / receive selector switch, 17,37…Antenna, 18,38…Receiving RF unit, 19,39…Receiving frequency converter, 20,40…Receiving IF unit, 21,41…Receiving AD converter, 22,25…Temperature sensor, 23…Transmitting temperature compensation setting and retention unit, 24…Transmitting bias / gain setting circuit, 26…Receiving temperature compensation setting and retention unit, 27…Receiving bias / gain setting circuit
Claims
1. In TDD radios, A transmit / receive selector switch that connects to the antenna, A signal processing unit controls the aforementioned transmit / receive switch, outputs a digital transmit signal, and inputs a digital receive signal. A DA converter that converts the aforementioned digital transmission signal into an analog transmission signal, A transmission IF section that attenuates noise and amplifies the analog transmission signal output from the DA converter, A transmission frequency converter that converts the analog transmission signal output from the transmission IF unit into a transmission frequency, A transmitting RF section that reduces spurious emissions from the analog transmission signal output from the aforementioned transmission frequency converter, amplifies the signal, and outputs it to the transmit / receive selector switch, A transmission temperature correction setting holding unit that outputs a transmission correction value corresponding to the temperature detected by the temperature sensor, A TDD radio characterized by comprising a transmit bias / gain setting circuit that corrects and sets the transmit bias voltage and amplification gain for the transmit IF section, the transmit frequency converter, and the transmit RF section using a transmit correction value from the transmit temperature correction setting and holding section.
2. A receiving RF section that amplifies the analog received signal from the transmit / receive switch, A receiving frequency converter that converts the analog received signal from the receiving RF section into an IF signal, A receiving IF section that attenuates and amplifies the spurious signals of the analog received signal from the aforementioned receiving frequency converter, An AD converter that converts the analog received signal from the receiving IF unit into a digital received signal and outputs it to the signal processing unit, A receiving temperature correction setting holding unit that outputs a receiving correction value corresponding to the temperature detected by the temperature sensor, The TDD radio according to claim 1, further comprising a receiving bias / gain setting circuit that corrects and sets the receiving bias voltage and amplification gain for the receiving RF section, the receiving frequency converter, and the receiving IF section using a receiving correction value from the receiving temperature correction setting and holding section.
3. The signal processing unit turns off the power to the transmission IF unit, the transmission frequency converter, and the transmission RF unit during the receiving operation section. The transmission temperature correction setting holding unit identifies the transmission correction value for the next transmission operation section during the reception operation section. The transmit bias / gain setting circuit corrects the transmit bias voltage and amplification gain using the transmit correction value from the transmit temperature correction setting holding unit at the start of the next transmit operation interval, and sets the corrected transmit bias voltage and amplification gain to the transmit IF unit, the transmit frequency converter, and the transmit RF unit. The TDD radio according to claim 1, characterized in that when the transmission bias voltage and amplification gain are set, the transmission IF section, the transmission frequency converter, and the transmission RF section operate with the set transmission bias voltage and amplification gain during the transmission operation period.
4. The signal processing unit turns off the power to the receiving RF unit, the receiving frequency converter, and the receiving IF unit during the transmission operation section. The receiving temperature correction setting holding unit identifies the receiving correction value for the next receiving operation section during the transmission operation section. The receiving bias / gain setting circuit corrects the receiving bias voltage and amplification gain using the receiving correction value from the receiving temperature correction setting holding unit at the start of the next receiving operation interval, and sets the corrected receiving bias voltage and amplification gain to the receiving IF unit, the receiving frequency converter, and the receiving RF unit. The TDD radio according to claim 2, characterized in that when the receiving IF section, the receiving frequency converter, and the receiving RF section are set, the receiving operation section operates with the set receiving bias voltage and amplification gain.
5. The TDD radio according to claim 3 or 4, characterized in that the transmitting temperature correction setting holding unit and the receiving temperature correction setting holding unit output the transmitting correction value or the receiving correction value that lowers the transmitting bias voltage and the receiving bias voltage and increases the amplification gain when the temperature from the temperature sensor rises, and output the transmitting correction value or the receiving correction value that raises the transmitting bias voltage and the receiving bias voltage and decreases the amplification gain when the temperature from the temperature sensor falls.
6. The transmission temperature correction setting holding unit includes a transmission table that stores transmission correction values for temperature, reads the transmission correction value corresponding to the temperature detected by the temperature sensor from the transmission table and outputs it to the transmission bias / gain setting circuit. The TDD radio according to claim 3 or 4, characterized in that the receiving temperature correction setting holding unit includes a receiving table for storing receiving correction values for temperature, and reads a receiving correction value corresponding to the temperature detected by the temperature sensor from the receiving table and outputs it to the receiving bias / gain setting circuit.