CN106301512B - Multi-subarray antenna beam switching method based on time delay quantization error minimization - Google Patents

Multi-subarray antenna beam switching method based on time delay quantization error minimization Download PDF

Info

Publication number
CN106301512B
CN106301512B CN201610771487.2A CN201610771487A CN106301512B CN 106301512 B CN106301512 B CN 106301512B CN 201610771487 A CN201610771487 A CN 201610771487A CN 106301512 B CN106301512 B CN 106301512B
Authority
CN
China
Prior art keywords
subarray
ttd
delay
quantization error
partition
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.)
Active
Application number
CN201610771487.2A
Other languages
Chinese (zh)
Other versions
CN106301512A (en
Inventor
贾维敏
姚敏立
刘杉
金伟
戴定成
谭志浩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rocket Force University of Engineering of PLA
Original Assignee
Rocket Force University of Engineering of PLA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Rocket Force University of Engineering of PLA filed Critical Rocket Force University of Engineering of PLA
Priority to CN201610771487.2A priority Critical patent/CN106301512B/en
Publication of CN106301512A publication Critical patent/CN106301512A/en
Application granted granted Critical
Publication of CN106301512B publication Critical patent/CN106301512B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/18578—Satellite systems for providing broadband data service to individual earth stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0602—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
    • H04B7/0805—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)

Abstract

The invention discloses a multi-subarray antenna beam switching method based on time delay quantization error minimization, which comprises the following steps: 1) for a multi-subarray phased array antenna, phase compensation is carried out by utilizing a plurality of sets of delay lines, the scanning range of the antenna is divided into a plurality of partitions, a maximum time delay quantization error model of each subarray is established in any partition, and the maximum time delay quantization error of each subarray in the whole scanning range is obtained; 2) establishing a delay quantization error model of each subarray in a scanning range, establishing an optimization model by taking the number of delay lines as an optimization object and taking the maximum delay quantization error of a multi-subarray antenna as an optimization target, and solving the optimization model to obtain the number of delay lines of each subarray; 3) and calculating the scanning range partition interval corresponding to each subarray and the length of each delay line according to the number of the delay lines of each subarray. The method can compensate the phase drift generated when the central frequency of the signal changes by utilizing a plurality of sets of delay lines, and realizes the minimum delay quantization error.

Description

Multi-subarray antenna beam switching method based on time delay quantization error minimization
Technical Field
The invention belongs to the technical field of antenna beam control of satellite communication systems, and relates to a multi-subarray antenna beam switching method based on time delay quantization error minimization.
Background
With the progress of times and the development of science and technology, the satellite communication technology is widely applied to the military and civil fields, the satellite communication technology in motion becomes an effective means for realizing broadband mobile communication, and plays an important role in the fields of emergent public event processing, emergency command, information real-time transmission and the like.
The multi-subarray technology can effectively reduce the height of the antenna and the cost of the system, and simultaneously gives consideration to the performance of the antenna, so that the method is the most common method for the low-profile antenna at present. In the feed network of a phased array antenna, the most important phase shifting devices are mainly phase shifters and delay lines, where the phase shift value of the phase shifter is independent of the signal frequency. The change of signal frequency can cause the antenna beam pointing direction to be deviated, and further cause the signal receiving power to be reduced. The delay line is also called delay device, it has the same group delay time, when it adopts real-time delay device to compensate space wave path difference, it can effectively raise antenna bandwidth, but its price is very expensive. The phase shift amount of the digital phase shifter is changed in a binary mode, and when the number of the phase shift bits of the digital phase shifter is b bits, the minimum phase shift value delta of the phase shifter is 2 pi/2bThe phase shift value that can be realized has 2bAnd (4) respectively. When the phase shift is performed by adopting the rounding method, the maximum phase shift deviation of the phase shifter is half of the minimum phase shift value, namely 2 pi/2b+1The maximum phase shift deviation of the phase shifter may also be referred to as the phase quantization error of the phase shifter.
As with the phase quantization error of the phase shifter, the delay quantization error of the delay device may be defined as the maximum delay variation of the delay device over the scan range. However, unlike the phase shift value of the phase shifter, the delay length of the delay device is not periodic, and for a large-aperture antenna, to improve the delay quantization accuracy of the delay device, a large number of complicated designs are required, which is one of the reasons that the real-time delay device is expensive.
In the currently common switched beam technology, a delay compensation method based on multiple sets of delay lines is usually adopted, which essentially means that a special delay device is added behind each subarray, and the delay precision of the delay device is related to the number of sets of delay lines and the position of the subarray. It is clear that the switched beam technique has a premise that the number of delay lines required for each sub-array is the same. In order to further improve the performance of the multi-subarray antenna, it is necessary to break the premise and research a feed network design method based on the minimization of the delay quantization error.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a multi-subarray antenna beam switching method based on time delay quantization error minimization, which can realize time delay error minimization of a multi-subarray antenna and has low cost.
In order to achieve the above object, the method for switching a beam of a multi-subarray antenna based on minimization of delay quantization error according to the present invention comprises the following steps:
1) compensating the phase difference of the multi-subarray antenna by adopting a plurality of sets of delay lines, dividing the scanning range of the multi-subarray antenna into p partitions, calculating the length L (n, q) of delay lines of other subarrays in any partition by taking the last subarray of the partition as a phase reference subarray, and establishing a time delay quantization error model delta L of each subarray in the partitionTTD(n, q) to obtain the maximum time delay quantization error delta L of the qth sub-array in the whole scanning rangeTTD(q)；
2) Let the total number of delay lines on all subarrays be NALLWherein, the last sub-array is used as the phase reference to establish the delay quantization error model delta L of the q sub-arrayTTD(q,NTTD(q)), then establishing an optimization model by taking the minimum maximum time delay quantization error of all the sub-arrays as an optimization target and the number of delay lines of each sub-array as an optimization variable, and then solving the optimization model to obtain the number of delay lines of each sub-array;
3) calculating the partition interval and the length of the delay line in each subarray scanning range according to the number of the delay lines of each subarray obtained in the step 2), and then switching the multi-subarray antenna beams according to the partition interval and the length of the delay line in each subarray scanning range.
The length L (n, q) of the delay line of other sub-arrays in the subarea in the step 1) is as follows:
wherein, betanIn the section Sn＝[αn,αn+1]N is 1,2, …, p, the delay line length exactly compensates the elevation angle corresponding to the wave path difference, and establishes the time delay quantization error model delta l of each sub-array in the partitionTTD(n, q) is:
Figure BDA0001098929400000032
wherein the content of the first and second substances,
Figure BDA0001098929400000033
for ideal delay line length of the q-th sub-array at elevation angle alpha, when cos betan＝(cosαn+cosαn+1) At the time of/2, the maximum time delay quantization error of each subarray reaches the minimum, and at the time
Figure BDA0001098929400000034
Due to the fact that
Figure BDA0001098929400000035
When n is 1,2, …, p, then there is Δ lTTD(1,q)＝ΔlTTD(n,q),n＝2,3,…,p。
Establishing a delay quantization error model delta L of the q-th sub-array by taking the last sub-array as a phase reference in step 2)TTD(q,NTTD(q)) is:
Figure BDA0001098929400000041
the optimization target is as follows:
Figure BDA0001098929400000042
wherein the content of the first and second substances,
NTTD＝[NTTD(1),NTTD(2),…,NTTD(Q)](6)
ΔLmax(NTTD)＝max{ΔLTTD(1,NTTD(1)),…,ΔLTTD(Q,NTTD(Q))} (7)。
the partition interval of each subarray scanning range in the step 3) is as follows:
Figure BDA0001098929400000043
cosβn＝(cosαn+cosαn+1)/2 (9)
wherein alpha isnBy dividing the position of spaced points, betanThe elevation angle corresponding to the phase difference compensated by the delay line in the nth partition is determined according to the elevation angle beta corresponding to the phase difference compensated by the delay line in the nth partitionnCalculating the length difference Delta L of the delay lines of the adjacent sub-arrays in the partitionn：
Figure BDA0001098929400000044
The invention has the following beneficial effects:
the invention relates to a multi-subarray antenna beam switching method based on time delay quantization error minimization, which adopts the principle that a plurality of delay lines compensate the phase difference of a multi-subarray antenna during specific operation, firstly establishes a time delay quantization error model of each subarray in a subarea to obtain the maximum time delay quantization error of each subarray in the whole scanning range, then constructs an optimization model by taking the minimum maximum time delay quantization error of each subarray as an optimization target and taking the number of delay lines of each subarray as an optimization variable to obtain the number of delay lines of each subarray corresponding to the minimum maximum time delay quantization error of each subarray, finally calculates the subarea interval and the length of the delay line in the scanning range of each subarray according to the number of delay lines of each subarray, breaks the limit that the number of the delay lines of each subarray in the beam switching technology is equal, and enables the feed network design of an antenna to obtain greater freedom degree, thereby further improving the antenna performance frequency response of the multi-subarray antenna. In addition, the method is simple and easy to implement, has low cost, can effectively promote the popularization and application of the communication-in-motion, and can well meet the requirement of the communication-in-motion antenna beam pointing.
Drawings
FIG. 1 is a schematic diagram of a two-stage phase compensation using a delay line according to the present invention;
fig. 2 is a schematic diagram of antenna scanning range division when multiple sets of delay lines are employed in the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
referring to fig. 1, the method for switching a multi-subarray antenna beam based on minimization of delay quantization error according to the present invention includes the following steps:
1) compensating the phase difference of the multi-subarray antenna by adopting a plurality of sets of delay lines, dividing the scanning range of the multi-subarray antenna into p partitions, calculating the length L (n, q) of delay lines of other subarrays in any partition by taking the last subarray of the partition as a phase reference subarray, and establishing a time delay quantization error model delta L of each subarray in the partitionTTD(n, q) to obtain the maximum time delay quantization error delta L of the qth sub-array in the whole scanning rangeTTD(q)；
2) Let the total number of delay lines on all subarrays be NALLWherein, the last sub-array is used as the phase reference to establish the delay quantization error model delta L of the q sub-arrayTTD(q,NTTD(q)), then establishing an optimization model by taking the minimum maximum time delay quantization error of all the sub-arrays as an optimization target and the number of delay lines of each sub-array as an optimization variable, and then solving the optimization model to obtain the number of delay lines of each sub-array;
3) calculating the partition interval and the length of the delay line in each subarray scanning range according to the number of the delay lines of each subarray obtained in the step 2), and then switching the multi-subarray antenna beams according to the partition interval and the length of the delay line in each subarray scanning range.
The length L (n, q) of the delay line of other sub-arrays in the subarea in the step 1) is as follows:
Figure BDA0001098929400000061
wherein, betanIn the section Sn＝[αn,αn+1]N is 1,2, …, p, the delay line length exactly compensates the elevation angle corresponding to the wave path difference, and establishes the time delay quantization error model delta l of each sub-array in the partitionTTD(n, q) is:
Figure BDA0001098929400000062
wherein the content of the first and second substances,
Figure BDA0001098929400000063
for ideal delay line length of the q-th sub-array at elevation angle alpha, when cos betan＝(cosαn+cosαn+1) At the time of/2, the maximum time delay quantization error of each subarray reaches the minimum, and at the time
Figure BDA0001098929400000064
Due to the fact that
Figure BDA0001098929400000065
When n is 1,2, …, p, then there is Δ lTTD(1,q)＝ΔlTTD(n,q),n＝2,3,…,p。
Establishing a delay quantization error model delta L of the q-th sub-array by taking the last sub-array as a phase reference in step 2)TTD(q,NTTD(q)) is:
Figure BDA0001098929400000066
the optimization target is as follows:
wherein the content of the first and second substances,
NTTD＝[NTTD(1),NTTD(2),…,NTTD(Q)](6)
ΔLmax(NTTD)＝max{ΔLTTD(1,NTTD(1)),…,ΔLTTD(Q,NTTD(Q))} (7)。
the partition interval of each subarray scanning range in the step 3) is as follows:
Figure BDA0001098929400000072
cosβn＝(cosαn+cosαn+1)/2 (9)
wherein alpha isnBy dividing the position of spaced points, betanThe elevation angle corresponding to the phase difference compensated by the delay line in the nth partition is determined according to the elevation angle beta corresponding to the phase difference compensated by the delay line in the nth partitionnCalculating the length difference Delta L of the delay lines of the adjacent sub-arrays in the partitionn：
Figure BDA0001098929400000073
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims (3)

1. A multi-subarray antenna beam switching method based on time delay quantization error minimization is characterized by comprising the following steps:
1) compensating the phase difference of the multi-subarray antenna by adopting a plurality of sets of delay lines, dividing the scanning range of the multi-subarray antenna into p partitions, calculating the length L (n, q) of delay lines of other subarrays in any partition by taking the last subarray of the partition as a phase reference subarray, and establishing a time delay quantization error model △ L of each subarray in the partitionTTD(n, q) to obtain the maximum time delay quantization error △ L of the qth sub-array in the whole scanning rangeTTD(q)；
2) Let the total number of delay lines on all subarrays be NALLWherein, the delay quantization error model △ L of the q-th sub-array is established by taking the last sub-array as the phase referenceTTD(q,NTTD(q)), and then optimizing the objective of minimizing the maximum delay quantization error of all the subarraysMarking and establishing an optimization model by taking the number of delay lines of each subarray as an optimization variable, and then solving the optimization model to obtain the number of the delay lines of each subarray;
3) calculating the partition interval and the length of the delay line in each subarray scanning range according to the number of the delay lines of each subarray obtained in the step 2), and then switching the multi-subarray antenna beams according to the partition interval and the length of the delay line in each subarray scanning range;
the length L (n, q) of the delay line of other sub-arrays in the subarea in the step 1) is as follows:
wherein, betanIn the section Sn＝[αn,αn+1]N is 1,2, …, p, the delay line length exactly compensates the elevation angle corresponding to the wave path difference, establishes the time delay quantization error model △ l of each sub-array in the partitionTTD(n, q) is:
wherein the content of the first and second substances,
Figure FDA0002149440610000013
for ideal delay line length of the q-th sub-array at elevation angle alpha, when cos betan＝(cosαn+cosαn+1) At the time of/2, the maximum time delay quantization error of each subarray reaches the minimum, and at the time
Figure FDA0002149440610000021
Due to the fact that
Figure FDA0002149440610000022
Then △ lTTD(1,q)＝△lTTD(n,q),n＝2,3,…,p，αnThe locations of the spaced points are partitioned.
2. The method for switching the multi-subarray antenna beam based on the minimization of the delay quantization error of claim 1, wherein in step 2), a delay quantization error model △ L of the qth subarray is established by using the last subarray as a phase referenceTTD(q,NTTD(q)) is:
Figure FDA0002149440610000023
the optimization target is as follows:
Figure FDA0002149440610000024
wherein the content of the first and second substances,
NTTD＝[NTTD(1),NTTD(2),…,NTTD(Q)](6)
△Lmax(NTTD)＝max{△LTTD(1,NTTD(1)),…,△LTTD(Q,NTTD(Q))} (7)。
3. the multi-subarray antenna beam switching method based on time delay quantization error minimization according to claim 2, wherein the interval of the sub-area of each subarray scanning range in step 3) is:
Figure FDA0002149440610000025
cosβn＝(cosαn+cosαn+1)/2 (9)
wherein alpha isnBy dividing the position of spaced points, betanThe elevation angle corresponding to the phase difference compensated by the delay line in the nth partition is determined according to the elevation angle beta corresponding to the phase difference compensated by the delay line in the nth partitionnCalculating the length difference △ L of the delay line of the adjacent sub-array in the partitionn：
CN201610771487.2A 2016-08-29 2016-08-29 Multi-subarray antenna beam switching method based on time delay quantization error minimization Active CN106301512B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201610771487.2A CN106301512B (en) 2016-08-29 2016-08-29 Multi-subarray antenna beam switching method based on time delay quantization error minimization

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201610771487.2A CN106301512B (en) 2016-08-29 2016-08-29 Multi-subarray antenna beam switching method based on time delay quantization error minimization

Publications (2)

Publication Number Publication Date
CN106301512A CN106301512A (en) 2017-01-04
CN106301512B true CN106301512B (en) 2020-01-24

Family

ID=57675894

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201610771487.2A Active CN106301512B (en) 2016-08-29 2016-08-29 Multi-subarray antenna beam switching method based on time delay quantization error minimization

Country Status (1)

Country Link
CN (1) CN106301512B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110311720B (en) * 2019-06-25 2021-01-15 联想(北京)有限公司 Antenna, control method and storage medium
CN112909525B (en) * 2021-01-21 2022-10-11 中国电力科学研究院有限公司 Diffraction-free microstrip line antenna array of wireless power transmission system and design method thereof
CN115580339B (en) * 2022-10-08 2023-12-29 江苏领创星通卫星通信科技有限公司 Antenna beam scanning method and device, electronic equipment and storage medium

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101056451A (en) * 2006-04-15 2007-10-17 兰州大学电子技术开发应用研究所 Method and device for implementing the multi-wave bundle intelligent antenna with the directional antenna
CN101916904A (en) * 2010-08-04 2010-12-15 中国人民解放军第二炮兵工程学院 Mobile satellite communication multi-subarray panel antenna array and optimization method thereof
US8346162B1 (en) * 2009-09-25 2013-01-01 Emc Satcom Technologies System and method for reducing VSAT apertures via satellite MIMO
CN105610478A (en) * 2016-02-15 2016-05-25 东南大学 Millimeter wave MIMO communication multi-subarray cooperative beam alignment method and millimeter wave MIMO communication multi-subarray cooperative beam alignment device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150083274A (en) * 2014-01-09 2015-07-17 한국전자통신연구원 Los mimo system for reducing distance among antennas and system of therof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101056451A (en) * 2006-04-15 2007-10-17 兰州大学电子技术开发应用研究所 Method and device for implementing the multi-wave bundle intelligent antenna with the directional antenna
US8346162B1 (en) * 2009-09-25 2013-01-01 Emc Satcom Technologies System and method for reducing VSAT apertures via satellite MIMO
CN101916904A (en) * 2010-08-04 2010-12-15 中国人民解放军第二炮兵工程学院 Mobile satellite communication multi-subarray panel antenna array and optimization method thereof
CN105610478A (en) * 2016-02-15 2016-05-25 东南大学 Millimeter wave MIMO communication multi-subarray cooperative beam alignment method and millimeter wave MIMO communication multi-subarray cooperative beam alignment device

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
多子阵平板天线波束指向频率响应分析与固定长度延迟线应用;林志强，秦丽平，姚敏立，沈晓卫;《电子与信息学报》;20110430;第33卷(第4期);第987-990页 *
宽带相控阵天线子阵延时随机配置优化研究;张金平，任波;《现代雷达》;20141130;第36卷(第11期);第14-17页 *

Also Published As

Publication number Publication date
CN106301512A (en) 2017-01-04

Similar Documents

Publication Publication Date Title
CN1194442C (en) Adaptive array antenna
CN106301512B (en) Multi-subarray antenna beam switching method based on time delay quantization error minimization
CN108390703B (en) Multi-beam phased array antenna mechanism
CN110336627B (en) Array antenna amplitude and phase regulation and control system based on time modulation and implementation method thereof
CN112259964B (en) Multi-subarray phased array antenna beam control device
EP2846400A2 (en) Antenna array, antenna device and base station
US6661376B2 (en) Tiled antenna with overlapping subarrays
WO2018040141A1 (en) Broadband three-beam array antenna
CN111624565B (en) Multi-area joint beam tracking method for large conformal phased array system
EP3067988A1 (en) Antenna and method for transmitting and receiving wireless signal
CN105390822A (en) Cylindrical integrated active phased-array antenna
US20240063537A1 (en) Phased Array Antenna, Scanning Method therefor, and Antenna System
WO2018040140A1 (en) Broadband five-beam array antenna
CN105490033A (en) L-shaped sub-array utilization method
US10523310B2 (en) Mobile device and method for wireless communication with at least one flying object
US20030122709A1 (en) Electronic active phase control array antenna, method for compensating for direction differences at the antenna, and satellite tracking system and method using the antenna
CN101916904A (en) Mobile satellite communication multi-subarray panel antenna array and optimization method thereof
CN105353356B (en) Conformal digital beam froming system based on array sliding window
CN107710508A (en) A kind of Phased Array Radar System and beam sweeping method
CN111813135B (en) Dual-coordinate system full-airspace array beam tracking method
US10473776B2 (en) Transmit-array antenna for a monopulse radar system
CN114337752B (en) High-efficiency side lobe suppression linear array antenna based on three-section type hybrid drive
RU2541888C1 (en) Multibeam microwave linear antenna array and two-dimensional antenna array based thereon
CN106209214B (en) One kind being based on the maximized multiple submatrixes antenna beam switching method of received signal power
US11677456B2 (en) Forming a beam from a subscriber module of a fixed wireless access communication system

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant