Modulation signal transmitting and receiving system and method based on IQ domain maximum ratio combination

Abstract

The invention relates to the technical field of wireless communication and digital signal processing, and provides a modulation signal receiving and transmitting system and method based on IQ domain maximum ratio merging, and particularly, a Delta-Sigma modulation technology is adopted at a transmitting end, a high-order modulation signal is converted into a low bit stream, and the precision requirement for a data converter is remarkably reduced; an IQ domain maximum ratio merging mechanism is introduced at a receiving end, after IQ imbalance is corrected through digital preprocessing, dynamic weighted merging is carried out according to the signal-to-noise ratio of each receiving branch, and diversity gain is effectively utilized. Through collaborative design of the transmitting end and the receiving end, the signal-to-noise ratio of a combined signal can be remarkably improved and the influence of channel fading and noise can be effectively suppressed under high-frequency and long-distance transmission conditions, so that the signal-to-noise ratio of a Delta-Sigma modulation signal can be effectively improved on the premise of ensuring that the noise shaping characteristic of the Delta-Sigma modulation signal is not destroyed, and the signal-to-noise ratio of the Delta-Sigma modulation signal can be effectively improved. And the demodulation reliability and the overall robustness of the system are greatly enhanced.

Description

Technical Field

[0001] This invention relates to the fields of wireless communication and digital signal processing technology, and more specifically, to a modulation signal transceiver system and method based on IQ domain maximum ratio combining. Background Technology

[0002] With the increasing demand for high-speed wireless communication, millimeter-wave and terahertz bands, due to their ability to provide large bandwidth resources, have gradually become important candidate technologies for wireless fronthaul, backhaul, and high-speed access systems. In such systems, photonic-assisted wireless communication technology can effectively reduce the complexity of the RF front-end and improve the system's flexibility and frequency scalability by generating and transmitting high-frequency carriers in the optical domain. However, high-frequency wireless signals face severe free-space path loss, atmospheric absorption, and non-ideal effects of the RF front-end during long-distance transmission, which places higher demands on the system's signal-to-noise ratio and stability. To reduce the resolution requirements of high-speed digital-to-analog converters and analog-to-digital converters, Delta-Sigma modulation technology has been introduced into the generation and transmission process of wireless signals, achieving low-bit representation of high-order modulated signals through oversampling and noise shaping. Although Delta-Sigma modulation has significant hardware advantages at the transmitting end, it is highly sensitive to noise and channel distortion in high-frequency, long-distance wireless links. Especially at the receiving end, IQ imbalance, frequency-selective fading, and multipath effects can destroy the noise shaping characteristics of Delta-Sigma modulated signals, leading to a significant decrease in demodulation performance. Existing systems mostly employ single-branch reception or simple combining methods, which struggle to effectively improve the reception robustness of Delta-Sigma modulated signals under complex wireless channel conditions. Therefore, there is an urgent need for a novel Delta-Sigma modulated wireless communication system that collaboratively designs the transmitter and receiver from a system architecture perspective, in order to improve the overall transmission performance and stability under high-frequency wireless links. Summary of the Invention

[0003] In view of this, the present invention proposes a modulation signal transceiver system and method based on IQ domain maximum ratio combining. By using Delta-Sigma modulation to generate low-bit high-frequency signals at the transmitting end and introducing an IQ domain weighted combining mechanism at the receiving end, the signal-to-noise ratio and demodulation reliability of the system under high-frequency, long-distance wireless transmission conditions are effectively improved.

[0004] To achieve the above objectives, this invention proposes a modulation signal transceiver system based on IQ domain maximum ratio combining, comprising a transmitter system and a receiver system connected via a wireless transmission channel; The transmitting system includes: The Delta-Sigma signal generation module is used to perform Delta-Sigma modulation on the original baseband signal to generate a low-bit Delta-Sigma digital signal. The radio frequency modulation module is used to modulate the low-bit Delta-Sigma digital signal onto the radio frequency carrier. The radio frequency (RF) transmission module is used to amplify and transmit the modulated RF signal. The receiving system includes: The radio frequency receiving and downconversion module is used to receive radio frequency signals and downconvert them into at least two independent IQ baseband signal branches. The digital preprocessing module is used to perform amplitude and phase compensation on each IQ baseband signal; The IQ domain weighted merging module is used to weight and merge the IQ baseband signals in the IQ domain. The Delta-Sigma demodulation and signal reconstruction module is used to demodulate and reconstruct the merged signal to restore the original baseband signal.

[0005] Furthermore, the Delta-Sigma modulation includes oversampling, noise shaping, and quantization. The Delta-Sigma signal generation module first generates a high-order quadrature amplitude modulation signal, which is then converted into a low-bit digital signal after oversampling and noise shaping.

[0006] Furthermore, the IQ domain weighted merging module calculates the corresponding weighted merging weight based on the signal-to-noise ratio information of each IQ baseband signal, and performs weighted merging of each IQ baseband signal in the IQ domain according to the weighted merging weight, thereby obtaining a merged signal with enhanced signal-to-noise ratio.

[0007] Furthermore, the digital preprocessing module is used to correct IQ imbalance caused by non-ideal RF front-end.

[0008] On the other hand, to achieve the above objectives, this invention proposes a modulation signal transmission and reception method based on IQ domain maximum ratio combining, comprising the following steps: At the transmitting end, the baseband signal is Delta-Sigma modulated to generate a low-bit digital signal, which is then modulated onto the radio frequency carrier and transmitted. At the receiving end, radio frequency signals are received and down-converted into multiple independent IQ baseband signals; Digital preprocessing is performed on each IQ baseband signal; Weighted merging of each IQ baseband signal within the IQ domain; The merged signal is demodulated and reconstructed using Delta-Sigma to recover the original baseband signal.

[0009] Furthermore, the weights for the weighted merging are adaptively calculated based on the real-time signal-to-noise ratio of each branch signal.

[0010] Furthermore, the Delta-Sigma modulation includes oversampling, noise shaping, and quantization steps to reduce the number of bits in the signal representation.

[0011] Furthermore, the digital preprocessing includes estimating and compensating for the IQ imbalance of the received signal.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs Delta-Sigma modulation technology to convert high-order modulated signals into low-bit streams, significantly reducing the accuracy requirements of the data converter and simplifying the complexity of the RF front-end hardware. At the receiver, an IQ domain maximum ratio combining mechanism is introduced. After digital preprocessing to correct IQ imbalance, dynamic weighted combining is performed based on the signal-to-noise ratio (SNR) of each receiving branch, effectively utilizing diversity gain. Through coordinated design at both the transmitting and receiving ends, this system can significantly improve the SNR of the combined signal under high-frequency, long-distance transmission conditions, effectively suppressing the effects of channel fading and noise. Thus, while ensuring that the noise-shaping characteristics of the Delta-Sigma modulated signal are not compromised, the reliability of demodulation and the overall robustness of the system are greatly enhanced. Attached Figure Description

[0013] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings: Figure 1 This is a schematic diagram of the modulation signal transceiver system framework based on IQ domain maximum ratio combining according to the present invention; wherein, 1 is the Delta-Sigma signal generation module, 2 is the radio frequency modulation module, 3 is the radio frequency transmission module, 4 is the radio frequency reception and down-conversion module, 5 is the digital preprocessing module, 6 is the IQ domain weighted combining module, and 7 is the Delta-Sigma demodulation and signal reconstruction module. Detailed Implementation

[0014] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0015] This embodiment proposes a modulation signal transceiver system based on IQ domain maximum ratio combining, such as... Figure 1As shown, the system includes a transmitter system and a receiver system, which are connected through a wireless transmission channel. In the figure, 1 is the Delta-Sigma signal generation module, 2 is the radio frequency modulation module, 3 is the radio frequency transmission module, 4 is the radio frequency reception and down-conversion module, 5 is the digital preprocessing module, 6 is the IQ domain weighted merging module, and 7 is the Delta-Sigma demodulation and signal reconstruction module.

[0016] At the transmitting end, the system includes a Delta–Sigma signal generation module 1, an RF modulation module 2, and an RF transmission module 3.

[0017] The Delta-Sigma signal generation module 1 is used to process the baseband modulated signal to be transmitted. Specifically, it first generates a high-order quadrature amplitude modulation signal as the original baseband signal, then oversamples this baseband signal, and performs noise shaping and quantization on the signal using a Delta-Sigma modulation structure, thereby converting the original high-order QAM signal into a low-bit Delta-Sigma digital signal. This approach significantly reduces the complexity of subsequent RF modulation and hardware implementation while ensuring signal quality within the band.

[0018] Subsequently, the Delta-Sigma digital signal is sent to the radio frequency modulation module 2, where the modulation process from digital signal to radio frequency carrier is completed. The radio frequency modulation module 2 loads the low-bit Delta-Sigma digital signal onto the radio frequency carrier to generate the corresponding radio frequency modulated signal.

[0019] The radio frequency transmission module 3 is used to amplify the modulated radio frequency signal and radiate it to the wireless transmission channel through the antenna to realize the wireless transmission of Delta–Sigma modulated signals.

[0020] At the receiving end, the system includes an RF receiving and down-conversion module 4, a digital preprocessing module 5, an IQ domain weighted merging module 6, and a Delta–Sigma demodulation and signal reconstruction module 7.

[0021] The radio frequency (RF) receiving and down-conversion module 4 is used to receive RF signals propagated through a wireless transmission channel and perform down-conversion processing on the RF signals, converting them into at least two independent IQ baseband signal branches. Each IQ baseband signal branch corresponds to a different receiving path or receiving channel.

[0022] Each IQ baseband signal branch is then fed into the digital preprocessing module 5. The digital preprocessing module 5 is used to digitally process each IQ baseband signal to compensate for the IQ amplitude mismatch and phase mismatch introduced by the RF front end and the mixing process, thereby obtaining the corrected baseband signal and providing a reliable input for subsequent merging processing.

[0023] After digital preprocessing, the corrected multi-channel baseband signals are sent to the IQ domain weighted combining module 6. The IQ domain weighted combining module 6 calculates the corresponding weighting combining weights based on the signal-to-noise ratio (SNR) information of each baseband signal, and then performs weighted combining of the multi-channel baseband signals in the IQ domain according to these weights, thereby obtaining a combined signal with enhanced SNR. This IQ domain weighted combining process effectively utilizes the diversity gain between the multiple received signals, mitigating the impact of channel fading and noise on system performance.

[0024] Finally, the merged baseband signal is sent to Delta–Sigma demodulation and signal reconstruction module 7. This module is used to demodulate and reconstruct the low-bit Delta–Sigma modulated signal. Through filtering and symbol mapping, it recovers the original high-order modulated signal, thus achieving reliable reconstruction of the transmitter baseband signal.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A modulation signal transceiving system based on IQ domain maximum ratio combining, characterized by, This includes transmitting and receiving systems connected via wireless transmission channels; The transmitting system includes: The Delta-Sigma signal generation module is used to perform Delta-Sigma modulation on the original baseband signal to generate a low-bit Delta-Sigma digital signal. The radio frequency modulation module is used to modulate the low-bit Delta-Sigma digital signal onto the radio frequency carrier. The radio frequency (RF) transmission module is used to amplify and transmit the modulated RF signal. The receiving system includes: The radio frequency receiving and downconversion module is used to receive radio frequency signals and downconvert them into at least two independent IQ baseband signal branches. The digital preprocessing module is used to perform amplitude and phase compensation on each IQ baseband signal; The IQ domain weighted merging module is used to weight and merge the IQ baseband signals in the IQ domain. The Delta-Sigma demodulation and signal reconstruction module is used to demodulate and reconstruct the merged signal to restore the original baseband signal.

2. The modulated signal transceiving system of claim 1, wherein The Delta-Sigma modulation includes oversampling, noise shaping, and quantization. The Delta-Sigma signal generation module first generates a high-order quadrature amplitude modulation signal. After oversampling and noise shaping, the high-order quadrature amplitude modulation signal is converted into a low-bit digital signal.

3. The modulation signal transceiver system according to claim 1, characterized in that, The IQ domain weighted merging module calculates the corresponding weighted merging weight based on the signal-to-noise ratio information of each IQ baseband signal, and performs weighted merging of each IQ baseband signal in the IQ domain according to the weighted merging weight, thereby obtaining a merged signal with enhanced signal-to-noise ratio.

4. The modulation signal transceiver system according to claim 1, characterized in that, The digital preprocessing module is used to correct IQ imbalance caused by non-ideal RF front-end.

5. A method for transmitting and receiving modulated signals based on IQ domain maximum ratio combining, characterized in that, Includes the following steps: At the transmitting end, the baseband signal is Delta-Sigma modulated to generate a low-bit digital signal, which is then modulated onto the radio frequency carrier and transmitted. At the receiving end, radio frequency signals are received and down-converted into multiple independent IQ baseband signals; Digital preprocessing is performed on each IQ baseband signal; Weighted merging of each IQ baseband signal within the IQ domain; The merged signal is demodulated and reconstructed using Delta-Sigma to recover the original baseband signal.

6. The method according to claim 5, characterized in that, The weights for the weighted merging are adaptively calculated based on the real-time signal-to-noise ratio of each branch signal.

7. The method according to claim 5, characterized in that, The Delta-Sigma modulation includes oversampling, noise shaping, and quantization steps to reduce the number of bits represented by the signal.

8. The method according to claim 5, characterized in that, The digital preprocessing includes estimating and compensating for the IQ imbalance of the received signal.

Images