CN114915350A - Low-complexity polarization rotation and carrier phase cooperative recovery method - Google Patents
Low-complexity polarization rotation and carrier phase cooperative recovery method Download PDFInfo
- Publication number
- CN114915350A CN114915350A CN202210501388.8A CN202210501388A CN114915350A CN 114915350 A CN114915350 A CN 114915350A CN 202210501388 A CN202210501388 A CN 202210501388A CN 114915350 A CN114915350 A CN 114915350A
- Authority
- CN
- China
- Prior art keywords
- polarization
- signal
- frequency
- carrier phase
- polarization rotation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
- H04B10/616—Details of the electronic signal processing in coherent optical receivers
- H04B10/6165—Estimation of the phase of the received optical signal, phase error estimation or phase error correction
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
- H04B10/616—Details of the electronic signal processing in coherent optical receivers
- H04B10/6162—Compensation of polarization related effects, e.g., PMD, PDL
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
The invention provides a low-complexity polarization rotation and carrier phase cooperative recovery method, which comprises the following steps: step 1: generating a signal with sub-carriers by a transmitting end, setting a guard bandwidth among the sub-carriers, and inserting pilot frequency PT with symmetrical frequency in the guard bandwidth of each polarization; step 2: converting the signals into analog signals through an arbitrary waveform generator, and sending the analog signals to a dual-polarization optical IQ modulator; and step 3: the signal is transmitted to a receiving end through an optical fiber; and 4, step 4: after passing through the band-pass optical filter, signal light and local oscillator light are acquired in a high-speed real-time acquisition oscilloscope after being detected by a coherent receiver, and acquired electric signals pass through a subsequent digital signal processing module; and 5: the digital signal processing module estimates the frequency offset by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency. The invention has the beneficial effects that: the invention has low calculation complexity, high polarization tracking speed and high polarization estimation precision.
Description
Technical Field
The invention relates to the field of optical communication, in particular to a low-complexity polarization rotation and carrier phase cooperative recovery method.
Background
Subcarrier multiplexing (SCM), polarization multiplexing (PDM) and coherent detection are enabling techniques for aggregation networks (e.g., 5G-Xhaul and passive optical networks), which may enable point-to-multipoint (PTMP) architectures while increasing transmission capacity. The PTMP architecture utilizes SCM to divide the high-bandwidth carrier into a plurality of low-bandwidth subcarriers that may be independently routed to and from different access nodes. In the access node, 5G forwarding is a special scenario, and a part of a transmission cable close to a base station of a radio frequency unit is overhead and is easily affected by environmental changes. Therefore, in PDM and SCM based PTMP optical fiber communication systems, polarization state tracking and phase recovery are key DSP modules at the receiving end. Unlike conventional coherent optical communication systems, convergence network applications are sensitive to power consumption and therefore cannot directly use conventional DSP algorithms. In addition, due to the large influence of the environment, the polarization rotation rate in a severe environment can reach hundreds of kilorad/s, and even higher than 8Mrad/s in the case of lightning strike, which requires that the corresponding DSP algorithm can tolerate fast polarization rotation. In summary, in order to adapt to the development of the next generation access convergence network, a scheme with low complexity, fast polarization rotation and carrier phase recovery is necessary.
In a conventional coherent DSP, polarization demultiplexing is typically implemented using a multiple-input multiple-output finite impulse response filter based on a constant modulus algorithm or a multi-mode algorithm. After polarization demultiplexing, carrier phase recovery is achieved by blind phase search algorithm (BPS) or viterbi-viterbi phase estimation (VVPE). However, these schemes have the disadvantages of slow polarization tracking speed and singularity. Furthermore, cascading polarization tracking and phase recovery will add additional computational complexity. It has also been proposed to use kalman and Nonlinear Principal Component Analysis (NPCA) to achieve polarization tracking and phase cooperative recovery, but the computational complexity of the algorithm remains unacceptable. Recently, researchers have proposed to calculate a jones matrix of the random birefringence of the fiber using a Pilot (PT), and extract the phase of the PT after polarization demultiplexing to compensate for the phase noise. However, in the polarization demultiplexing process, the complicated calculation increases power consumption while decreasing polarization estimation accuracy. Furthermore, polarization tracking and phase recovery are separated, which further increases computational complexity.
Disclosure of Invention
The invention provides a low-complexity polarization rotation and carrier phase cooperative recovery method, which comprises the following steps of:
step 1: a signal having subcarriers, between each of which a guard bandwidth is set, is generated by a transmitting end, and PTs are inserted at symmetrical frequencies in the guard bandwidth of each polarization.
Step 2: and (3) converting the signal in the step (1) into an analog signal through an arbitrary waveform generator, and sending the analog signal to a dual-polarization optical IQ modulator to obtain a modulated optical signal.
And 3, step 3: the signal is transmitted to the receiving end through the optical fiber.
And 4, step 4: after passing through the band-pass optical filter, the signal light and the local oscillator light are acquired in the high-speed real-time acquisition oscilloscope after being detected by the coherent receiver, and the acquired electric signals pass through the subsequent off-line digital signal processing module.
And 5: the digital signal processing module estimates the frequency offset by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency;
step 6: and (3) shifting the PT frequencies of the two polarization states to zero frequency according to the formula (4) and the formula (5), then respectively extracting the PT of the two polarization states by using a low-pass filter, obtaining an estimation matrix of polarization and phase by extracting the PT, and realizing the cooperative recovery of the polarization and the phase according to the estimation matrix.
And 7: and simultaneously compensating polarization rotation and carrier phase noise according to the estimation matrix obtained in the step 6.
As a further improvement of the present invention, in said step 1, a signal having three subcarriers is generated by the transmitting side DSP, a guard bandwidth is set between each subcarrier, the guard bandwidth is greater than 500MHz, and one PT is inserted at a symmetrical frequency in the guard bandwidth of each polarization.
As a further improvement of the present invention, in step 1, a signal with three subcarriers is generated by the transmitting end DSP, and the baud rate of each subcarrier depends on the actual requirement.
As a further improvement of the present invention, in step 1, each subcarrier is mapped to a desired modulation format signal by a mutually independent pseudo-random bit sequence; the pulse shaping uses a root raised cosine filter.
As a further improvement of the present invention, in the step 1, the method further comprises: the PTs are inserted at symmetrical frequencies within the X-polarization and Y-polarization protection bandwidths, respectively.
As a further improvement of the present invention, in the step 5, the following steps are further performed:
step 50: the digital signal processing module first compensates for IQ delay and imbalance.
Step 51: the frequency offset is estimated by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency.
As a further improvement of the present invention, step 7 further includes:
the intersymbol interference ISI and the residual slowly varying phase noise are further compensated using DDLMS.
As a further improvement of the present invention, in step 6, the frequency of PT is shifted to zero frequency, PT is extracted by a low-pass filter, and polarization and phase cooperative recovery is realized by extracting information of PT.
The invention has the beneficial effects that: 1. the polarization rotation and carrier phase cooperative recovery method of the invention carries out polarization tracking and phase recovery together, not only has low computational complexity and fast polarization tracking speed, but also has high polarization estimation precision; 2. the polarization rotation and carrier phase cooperative recovery method has high polarization tracking speed.
Drawings
FIG. 1 is a transmitted signal spectrum of the present invention; wherein FIG. 1a is the spectrum of the X-polarized signal and FIG. 1b is the spectrum of the Y-polarized signal;
FIG. 2 is a schematic block diagram of the polarization rotation and carrier phase cooperative recovery method of the present invention;
FIG. 3 is the required OSNR for different RSOP slew rates 3.8e-3 errors of the present invention.
Detailed Description
The noun explains:
PT: pilot frequency;
SCM: multiplexing of subcarriers;
and (2) BPS: blind phase search algorithm;
QAM: quadrature amplitude modulation;
IQ: in-phase quadrature;
DDLMS: a direct decision least mean square algorithm;
RSOP: rotating the polarization state;
OSNR: optical signal to noise ratio.
The invention discloses a low-complexity polarization rotation and carrier phase cooperative recovery method, which comprises the following steps:
1) system model and principles
Fig. 1(a) and (b) show SCM signal frequency spectrums under 3 subcarriers, a guard bandwidth is arranged among each subcarrier, and a PT is inserted in a symmetrical frequency in the guard bandwidth of each polarization. The transmit signal may be represented as:
wherein E x/y (t),S x/y (t) represents the X/Y polarized emission signal and SCM signal, respectively, and A, ω represent the amplitude and angular frequency, respectively, of PT. The power of the added PT depends on the pilot signal power ratio (PSR), defined as PSR (db) 10log10 (P) pilot /P signal ). Neglecting polarization mode dispersion and polarization dependent loss, the received signal can be expressed as:
wherein R is x/y (t)，J(t)，Δω，
Respectively representing the received X/Y polarized signals, a time-varying Jones matrix caused by random double refraction in the optical fiber, frequency deviation between laser at a transmitting end and local oscillation light, carrier phase noise and additive white Gaussian noise. Since the frequency spectrums of the signal and PT do not overlap, PT (pilot) can be extracted by a low pass filter after PT shifts to zero frequency. Therefore, for convenience, the following derivation ignores the influence of the signal. Substituting formula (1) into formula (2) to obtain:
since the PT frequencies are symmetrical, the frequency offset Δ ω can be estimated directly by calculating the deviation between the sum of two PT frequencies and the zero frequency. After estimating the frequency offset, shifting the frequency of the PT to zero frequency, and extracting the PT by using a low-pass filter, so that a matrix M can be obtained as follows:
wherein H {. denotes a low pass filter operation, {. cndot. } -1 Representing the inverse of the matrix.
As shown in fig. 2, the method for low-complexity cooperative recovery of polarization rotation and carrier phase disclosed by the present invention includes the following steps:
step 1: a signal having subcarriers, between each of which a guard bandwidth is set, is generated by a transmitting end, and a PT is inserted at a symmetrical frequency in the guard bandwidth of each polarization.
A signal with three subcarriers is generated by the transmitting end DSP, the total baud rate is 30GBaud, and the baud rate of each subcarrier is 10 GBaud. Each subcarrier is mapped to a 16-QAM signal by a mutually independent pseudo-random bit sequence. The pulse shaping uses a root raised cosine filter with a roll-off coefficient of 0.1. A 2GHz guard band is left between the sub-carriers in the SCM. PT is inserted at 6GHz in the X polarization and PT is inserted at-6 GHz in the Y polarization. The frequency spectrum of the resulting signal is shown in fig. 1.
Step 2: and (3) converting the signal in the step (1) into an analog signal through an arbitrary waveform generator, and sending the analog signal to a dual-polarization optical IQ modulator to obtain a modulated optical signal. The modulated optical signal is loaded into a standard single mode optical fiber and a variable optical attenuator is used to adjust the signal power.
And step 3: the signal is transmitted to the receiving end through the optical fiber.
An example of step 3 may be: firstly, in an optical fiber link, random polarization rotation is introduced by using a polarization scrambler; then, white gaussian noise is generated by a noise source with variable power and coupled with the optical signal obtained by the dual-polarization optical IQ modulator in step 2 by an optical coupler.
And 4, step 4: after passing through the band-pass optical filter, the signal light and the local oscillator light are acquired in the high-speed real-time acquisition oscilloscope after being detected by the coherent receiver, and the acquired electric signals pass through the subsequent off-line digital signal processing module.
And 5: the digital signal processing module estimates the frequency offset by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency.
The step 5 further comprises the following steps:
step 50: the digital signal processing module first compensates for IQ delay and imbalance.
Step 51: the frequency offset is estimated by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency.
Step 6: and (3) shifting the PT frequencies of the two polarization states to zero frequency according to the formula (4) and the formula (5), then respectively extracting the PT of the two polarization states by using a low-pass filter, obtaining an estimation matrix of polarization and phase by extracting the PT, and realizing the cooperative recovery of the polarization and the phase according to the estimation matrix.
And 7: and simultaneously compensating polarization rotation and carrier phase noise according to the estimation matrix obtained in the step 6.
Fig. 3 shows OSNR achievement cost curves for different polarization and phase tracking schemes at 7% FEC BER threshold for different RSOP rotation rates. As can be seen from FIG. 3, at a slow RSOP rotation rate of 100krad/s, the scheme of the present invention has an OSNR penalty of 0.9dB relative to the conventional MMA + BPS scheme, but the proposed scheme reduces the OSNR penalty of 0.2dB relative to the existing scheme. Furthermore, the required OSNR for the inventive scheme is essentially constant with increasing RSOP rotation rate, at a RSOP of 20Mrad/s there is only a penalty of 0.18dB, compared to the prior art scheme, the inventive scheme has an OSNR gain of 2.81 dB. This can show that the solution of the present invention has a significant improvement in performance over the prior art solutions.
The invention has the beneficial effects that: 1. the polarization rotation and carrier phase cooperative recovery method carries out polarization tracking and phase recovery together, and has the advantages of low calculation complexity, high polarization tracking speed and high polarization estimation precision; 2. the polarization rotation and carrier phase cooperative recovery method has high polarization tracking speed.
The foregoing is a further detailed description of the invention in connection with specific preferred embodiments and it is not intended to limit the invention to the specific embodiments described. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (8)
1. A low-complexity polarization rotation and carrier phase cooperative recovery method is characterized by comprising the following steps:
step 1: generating a signal with subcarriers by a transmitting end, setting a guard bandwidth among each subcarrier, and inserting a PT (potential transformer) in the guard bandwidth of each polarization at a symmetrical frequency;
step 2: converting the signal in the step 1 into an analog signal through an arbitrary waveform generator, and sending the analog signal to a dual-polarization optical IQ modulator to obtain a modulated optical signal;
and step 3: the optical signal is transmitted to a receiving end through an optical fiber;
and 4, step 4: after passing through the band-pass optical filter, the signal light and the local oscillator light are acquired in the high-speed real-time acquisition oscilloscope after being detected by the coherent receiver, and the acquired electric signal passes through a subsequent off-line digital signal processing module;
and 5: the digital signal processing module estimates the frequency offset by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency;
step 6: extracting amplitude and phase information of PT through low-pass filtering to estimate polarization rotation and phase noise;
and 7: and simultaneously compensating polarization rotation and carrier phase noise according to the estimation matrix obtained in the step 6.
2. The method of claim 1, wherein the method comprises: in step 1, a signal having three subcarriers is generated by the transmitting-end DSP, a guard bandwidth is set between each subcarrier, and a PT of one is inserted at a symmetrical frequency in the guard bandwidth of each polarization.
3. The method of claim 2, wherein the method comprises: in said step 1, a signal with three subcarriers is generated by the transmitting side DSP.
4. The method of claim 2, wherein: in the step 1, each subcarrier is mapped into a signal with a required modulation format by a mutually independent pseudo-random bit sequence; the pulse shaping uses a root raised cosine filter.
5. The method for cooperative recovery of polarization rotation and carrier phase according to claim 2, further comprising, in the step 1: PT is inserted in X polarization and PT is inserted in Y polarization.
6. The cooperative recovery method for polarization rotation and carrier phase according to claim 1, further comprising the following steps in step 5:
step 50: the digital signal processing module firstly compensates IQ time delay and imbalance;
step 51: the frequency offset is estimated by calculating the deviation between the sum of the frequencies of the two PTs and the zero frequency.
7. The method for cooperative recovery of polarization rotation and carrier phase according to claim 1, further comprising in step 7:
the intersymbol interference ISI and the residual slowly varying phase noise are further compensated using DDLMS.
8. The method for cooperative recovery of polarization rotation and carrier phase according to claim 1, wherein in the step 6, PT frequencies of two polarization states are shifted to zero frequency according to formula (4) and formula (5), then PT of two polarization states are respectively extracted by a low pass filter, an estimation matrix of polarization and phase can be obtained by extracting PT, and cooperative recovery of polarization and phase is realized according to the estimation matrix;
where H {. cndot.) represents a low pass filter operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210501388.8A CN114915350B (en) | 2022-05-10 | 2022-05-10 | Low-complexity polarization rotation and carrier phase collaborative recovery method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210501388.8A CN114915350B (en) | 2022-05-10 | 2022-05-10 | Low-complexity polarization rotation and carrier phase collaborative recovery method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114915350A true CN114915350A (en) | 2022-08-16 |
| CN114915350B CN114915350B (en) | 2023-07-25 |
Family
ID=82767132
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210501388.8A Active CN114915350B (en) | 2022-05-10 | 2022-05-10 | Low-complexity polarization rotation and carrier phase collaborative recovery method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114915350B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110274442A1 (en) * | 2010-05-07 | 2011-11-10 | Tyco Electronics Subsea Communications Llc | Pilot symbol aided carrier phase estimation |
| CN104393917A (en) * | 2014-10-31 | 2015-03-04 | 哈尔滨工业大学深圳研究生院 | Polarization state rapid tracking monitoring method based on Kalman filtering |
| CN107707310A (en) * | 2017-09-20 | 2018-02-16 | 哈尔滨工业大学深圳研究生院 | A kind of polarization demultiplexing and carrier phase recovery method based on adaptive Kalman |
| CN112804008A (en) * | 2021-03-11 | 2021-05-14 | 上海交通大学 | Polarization fast tracking and phase recovery system and method based on frequency domain pilot signal |
-
2022
- 2022-05-10 CN CN202210501388.8A patent/CN114915350B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110274442A1 (en) * | 2010-05-07 | 2011-11-10 | Tyco Electronics Subsea Communications Llc | Pilot symbol aided carrier phase estimation |
| CN102870353A (en) * | 2010-05-07 | 2013-01-09 | 泰科电子海底通信有限责任公司 | Pilot symbol aided carrier phase estimation |
| CN104393917A (en) * | 2014-10-31 | 2015-03-04 | 哈尔滨工业大学深圳研究生院 | Polarization state rapid tracking monitoring method based on Kalman filtering |
| CN107707310A (en) * | 2017-09-20 | 2018-02-16 | 哈尔滨工业大学深圳研究生院 | A kind of polarization demultiplexing and carrier phase recovery method based on adaptive Kalman |
| CN112804008A (en) * | 2021-03-11 | 2021-05-14 | 上海交通大学 | Polarization fast tracking and phase recovery system and method based on frequency domain pilot signal |
Non-Patent Citations (1)
| Title |
|---|
| JUNTAO CAO 等: "A Pilot Symbols Aided Adaptive Kalman Filter for Joint Carrier Phase and Polarization Tracking in Coherent Optical System", pages 1 - 12 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114915350B (en) | 2023-07-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108566250B (en) | Modulation and demodulation method and system based on carrier quadrature bias single sideband signal | |
| Matsushita et al. | High-spectral-efficiency 600-Gbps/carrier transmission using PDM-256QAM format | |
| Gonzalez et al. | Optical phase-modulated radio-over-fiber links with k-means algorithm for digital demodulation of 8PSK subcarrier multiplexed signals | |
| Shi et al. | 112 Gb/s/λ CAP Signals Transmission over 480 km in IM-DD System | |
| Matsumoto et al. | Fast, low-complexity widely-linear compensation for IQ imbalance in burst-mode 100-Gb/s/λ coherent TDM-PON | |
| Zhang et al. | 224-Gb/s 16QAM SV-DD transmission using pilot-assisted polarization recovery with integrated receiver | |
| Diniz et al. | Hardware-efficient chromatic dispersion estimator based on parallel Gardner timing error detector | |
| CN115804026A (en) | Apparatus and method for mitigating multipath interference in an optical fiber transmission system | |
| Jiang et al. | Joint time/frequency synchronization and chromatic dispersion estimation with low complexity based on a superimposed FrFT training sequence | |
| Dou et al. | 420Gbit/s DP-64QAM Nyquist-FDM single-carrier system | |
| CN114915350B (en) | Low-complexity polarization rotation and carrier phase collaborative recovery method | |
| CN116260523A (en) | Simplified homologous coherent system based on Alamouti coding | |
| Rasheed et al. | 128-QAM x 8 channels DWDM communication for optical fiber networks | |
| Kasai et al. | Backward-Rayleigh-scattering suppressed 160 Gbit/s 256 QAM injection-locked bidirectional coherent transmission for next generation mobile fronthaul | |
| Chen et al. | Blind identification of the shaping rate for probabilistic shaping QAM signal | |
| Zhang | Research on channel estimation based on DFT algorithm in CO-OFDM system | |
| Zou et al. | 100 GBaud SSB PAM-4 signal transmission over 80-km SMF with THP and KK receiver | |
| Li et al. | A multidimensional signal receiver based on time interleaved phase diversity detection | |
| Kodama et al. | Energy-efficient coherent PON system with access-span length difference between ONUs using marginal IQ power loading in downlink transmission | |
| Ferreira et al. | Optimization of OFDM parameters for 10-Gbps long reach coherent PONs | |
| Ge et al. | An efficient channel estimation algorithm for PDM CO-OFDM WDM system | |
| Wang et al. | WDM transmission system based on coherent optical OFDM and its performance analysis | |
| Fattah et al. | Electronic signal processing for cancelation of optical systems impairments | |
| Su et al. | DC restoration by data-aided sequence in Kramers-Kronig receiver | |
| Altabas et al. | Advanced technologies for coherent access networks |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |