CN113225291A - Ad hoc network synchronization system based on OFDM and method thereof - Google Patents

Ad hoc network synchronization system based on OFDM and method thereof Download PDF

Info

Publication number
CN113225291A
CN113225291A CN202110401737.4A CN202110401737A CN113225291A CN 113225291 A CN113225291 A CN 113225291A CN 202110401737 A CN202110401737 A CN 202110401737A CN 113225291 A CN113225291 A CN 113225291A
Authority
CN
China
Prior art keywords
baseband
ofdm
frequency
hoc network
module
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.)
Pending
Application number
CN202110401737.4A
Other languages
Chinese (zh)
Inventor
王志刚
盖平
丁高泉
王进帅
章灵芝
胡浩瀚
单宝麟
张立
孙亮
边立云
张溦
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.)
Tianjin Richsoft Electric Power Information Technology Co ltd
State Grid Information and Telecommunication Co Ltd
Original Assignee
Tianjin Richsoft Electric Power Information Technology Co ltd
State Grid Information and Telecommunication Co Ltd
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 Tianjin Richsoft Electric Power Information Technology Co ltd, State Grid Information and Telecommunication Co Ltd filed Critical Tianjin Richsoft Electric Power Information Technology Co ltd
Priority to CN202110401737.4A priority Critical patent/CN113225291A/en
Publication of CN113225291A publication Critical patent/CN113225291A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2647Arrangements specific to the receiver only
    • H04L27/2655Synchronisation arrangements
    • H04L27/2657Carrier synchronisation

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

The invention provides an OFDM-based ad hoc network synchronization system and a method thereof. The ad hoc network synchronization system based on OFDM and the method thereof comprise a radio frequency, an intermediate frequency, a baseband, an operation module and a record storage module, wherein the radio frequency: the function of transmitting signals remotely; intermediate frequency: a signal obtained by frequency-converting a high-frequency signal; baseband: original electrical signal without modulation for sending; an operation module: the sequence used for adjusting the frequency offset of the received baseband signal and the locally generated synchronous sequence is operated to obtain a relevant numerical value; a record storage module: the device is used for recording and storing relevant numerical values, the radio frequency is electrically connected with the intermediate frequency, the intermediate frequency is electrically connected with the baseband, the baseband is electrically connected with the operation module, and the operation module is electrically connected with the recording and storing module. The OFDM-based ad hoc network synchronization system and the method thereof have the advantages of reducing the frequency shift calculation again on the baseband signals, reducing the operation amount and improving the efficiency of synchronous detection.

Description

Ad hoc network synchronization system based on OFDM and method thereof
Technical Field
The invention relates to the technical field of wireless communication, in particular to an OFDM-based ad hoc network synchronization system and a method thereof.
Background
The main idea of OFDM is as follows: the channel is divided into a plurality of orthogonal sub-channels, the high-speed data signal is converted into parallel low-speed sub-data streams, and the parallel low-speed sub-data streams are modulated to be transmitted on each sub-channel. The orthogonal signals may be separated by correlation techniques at the receiving end, which may reduce the mutual interference (ISI) between the subchannels. The signal bandwidth on each subchannel is smaller than the associated bandwidth of the channel, so that flat fading can be seen on each subchannel, thereby eliminating inter-symbol interference, and since the bandwidth of each subchannel is only a small fraction of the original channel bandwidth, channel equalization becomes relatively easy.
The received baseband signal and the sequence adjusted by the frequency offset of the locally generated synchronization sequence cannot be directly operated by the operation module, so that frequency shift calculation needs to be performed on the baseband signal again, the operation amount is increased, and the efficiency of synchronous detection is reduced.
Therefore, there is a need to provide a new OFDM-based ad hoc network synchronization system and method thereof to solve the above technical problems.
Disclosure of Invention
In order to solve the above technical problems, the present invention provides an OFDM-based ad hoc network synchronization system and method that reduces the frequency shift calculation again for baseband signals, reduces the amount of computation, and improves the efficiency of synchronization detection.
The invention provides an OFDM-based ad hoc network synchronization system and a method thereof, wherein the OFDM-based ad hoc network synchronization system comprises: radio frequency, intermediate frequency, baseband, operation module and record storage module, the radio frequency: the function of transmitting signals remotely; intermediate frequency: a signal obtained by frequency-converting a high-frequency signal; baseband: original electrical signal without modulation for sending; an operation module: the sequence used for adjusting the frequency offset of the received baseband signal and the locally generated synchronous sequence is operated to obtain a relevant numerical value; a record storage module: the device is used for recording and storing relevant numerical values, the radio frequency is electrically connected with the intermediate frequency, the intermediate frequency is electrically connected with the baseband, the baseband is electrically connected with the operation module, and the operation module is electrically connected with the recording and storing module.
Preferably, the radio frequency and the intermediate frequency are in one-way electrical connection, the intermediate frequency and the baseband are in one-way electrical connection, and the baseband and the operation module are in one-way electrical connection.
Preferably, the operation module is in bidirectional electrical connection with the record storage module.
Preferably, the recording storage module is further provided with a WIFI module, and the recording storage module is electrically connected with the WIFI module.
A synchronization method of an ad hoc network synchronization system based on OFDM comprises the following steps:
the method comprises the following steps: synchronous sequence design, signal is transmitted on two OFDM symbols with the time domain length of 128, wherein NZC139, each sequence length 139,
Figure RE-GDA0003146799170000021
dividing the generated sequence into two parts, wherein 72 bits of the former part are placed on a first ofdm symbol, 67 bits of the latter part are placed on a second ofdm symbol, and the time domain sending signal is that the time domain data length is 128:
Figure RE-GDA0003146799170000022
t when the set position is the first ofdm symbolCPIs 10, L ═ 72; t when the set position is the second ofdm symbolCPIs 9, L ═ 67;
step two: the frame structure sent by the air interface is shown in fig. 3;
step three: the frame structure of the synchronization, the time domain signal mapping position of the synchronization sequence is shown in fig. 4;
step four: the correlation verification under the current synchronization sequence configuration can obtain better auto-correlation and cross-correlation characteristics by screening proper u values, and the u values are selected as follows: 71113161720212829303334394146485154889198100106108109110111119120122123126, respectively;
using the above selected u values, the correlation characteristics are shown in fig. 5;
step five: when accessing the ad hoc network, the synchronization detection device user needs to detect all synchronization sequences and determine the user resources that can be currently contacted.
Compared with the related technology, the ad hoc network synchronization system and the method thereof based on the OFDM have the following beneficial effects:
1. a synchronous system design based on OFDMA ad hoc network is provided, the device refers to 12 subcarriers and 7 OFDM symbols of LTE to be the most RB resource, and 6RB is the smallest schedulable resource. Each user transmits a synchronization sequence on the 6RB resource of the central frequency point. A maximum of 16 users may be allowed to access the ad hoc network system in the case where the system uses 100 RBs.
2. The synchronous detection device can directly carry out the operation module on the received baseband signal and the sequence of the frequency offset adjustment of the locally generated synchronous sequence, thereby reducing the frequency shift calculation of the baseband signal again, reducing the operation amount and improving the efficiency of synchronous detection.
Drawings
Fig. 1 is a schematic diagram of LTE resource allocation in the present invention;
FIG. 2 is a block diagram of the synchronization detection apparatus of the present invention;
fig. 3 is a block diagram of a frame structure transmitted by the air interface of the present invention;
fig. 4 is a schematic diagram of the time domain signal mapping position of the synchronization sequence according to the present invention.
FIG. 5 is a diagram illustrating the correlation characteristics of the u value according to the present invention.
Detailed Description
The invention is further described with reference to the following figures and embodiments.
Please refer to fig. 1-5, wherein fig. 1 is a schematic diagram illustrating a resource allocation situation of LTE in the present invention; FIG. 2 is a block diagram of the synchronization detection apparatus of the present invention; fig. 3 is a block diagram of a frame structure transmitted by the air interface of the present invention; FIG. 4 is a diagram illustrating the mapping positions of the time domain signals of the synchronization sequence according to the present invention; FIG. 5 is a diagram illustrating the correlation characteristics of the u value according to the present invention. The method comprises the following steps: radio frequency, intermediate frequency, baseband, operation module and record storage module.
In the specific implementation process, as shown in fig. 1 and 2, the radio frequency: the function of transmitting signals remotely; intermediate frequency: a signal obtained by frequency-converting a high-frequency signal; baseband: original electrical signal without modulation for sending; an operation module: the sequence used for adjusting the frequency offset of the received baseband signal and the locally generated synchronous sequence is operated to obtain a relevant numerical value; a record storage module: the device is used for recording and storing relevant numerical values, the radio frequency is electrically connected with the intermediate frequency, the intermediate frequency is electrically connected with the baseband, the baseband is electrically connected with the operation module, and the operation module is electrically connected with the recording and storing module.
The radio frequency and the intermediate frequency are in one-way electric connection, the intermediate frequency and the baseband are in one-way electric connection, the baseband and the operation module are in one-way electric connection, and the one-way electric connection ensures that data are normally transmitted to the next stage.
The operation module is in bidirectional electric connection with the record storage module, the operation module is in bidirectional electric connection, data after operation can be recorded in the record storage module, and the data in the record storage module can be extracted to the operation module to be verified and calculated.
Still install the WIFI module on the record storage module, record storage module is connected with the WIFI module electricity, needs to explain, can transmit information for mobile terminal through the WIFI module mode.
The synchronization method of the ad hoc network synchronization system based on OFDM comprises the following specific steps:
the method comprises the following steps: synchronous sequence design, signal is transmitted on two OFDM symbols with the time domain length of 128, wherein NZC139, each sequence length 139,
Figure RE-GDA0003146799170000041
dividing the generated sequence into two parts, wherein 72 bits of the former part are placed on a first ofdm symbol, 67 bits of the latter part are placed on a second ofdm symbol, and the time domain sending signal is that the time domain data length is 128:
Figure RE-GDA0003146799170000042
t when the set position is the first ofdm symbolCPIs 10, L ═ 72; t when the set position is the second ofdm symbolCPIs 9, L ═ 67;
step two: the frame structure sent by the air interface is shown in fig. 3;
step three: the frame structure of the synchronization, the time domain signal mapping position of the synchronization sequence is shown in fig. 4;
step four: the correlation verification under the current synchronization sequence configuration can obtain better auto-correlation and cross-correlation characteristics by screening proper u values, and the u values are selected as follows: 71113161720212829303334394146485154889198100106108109110111119120122123126, respectively;
using the above selected u values, the correlation characteristics are shown in fig. 5;
step five: when accessing the ad hoc network, the synchronization detection device user needs to detect all synchronization sequences and determine the user resources that can be currently contacted.
The circuits and controls involved in the present invention are prior art and will not be described in detail herein.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (5)

1. An OFDM-based ad hoc network synchronization system, comprising: radio frequency, intermediate frequency, baseband, operation module and record storage module, the radio frequency: the function of transmitting signals remotely; intermediate frequency: a signal obtained by frequency-converting a high-frequency signal; baseband: original electrical signal without modulation for sending; an operation module: the sequence used for adjusting the frequency offset of the received baseband signal and the locally generated synchronous sequence is operated to obtain a relevant numerical value; a record storage module: the device is used for recording and storing relevant numerical values, the radio frequency is electrically connected with the intermediate frequency, the intermediate frequency is electrically connected with the baseband, the baseband is electrically connected with the operation module, and the operation module is electrically connected with the recording and storing module.
2. The OFDM-based ad hoc network synchronization system of claim 1, wherein the rf and the if are in unidirectional electrical connection, the if and the baseband are in unidirectional electrical connection, and the baseband and the operation module are in unidirectional electrical connection.
3. The OFDM-based ad hoc network synchronization system of claim 1, wherein said operation module is bidirectionally electrically connected to said record storage module.
4. The OFDM-based ad hoc network synchronization system of claim 1, wherein a WIFI module is further installed on the recording storage module, and the recording storage module is electrically connected with the WIFI module.
5. The method for synchronizing the ad-hoc network with the system based on the OFDM according to any one of claims 1 to 4, wherein the specific steps are as follows:
the method comprises the following steps: synchronous sequence design, signal is transmitted on two OFDM symbols with the time domain length of 128, wherein NZC139, each sequence length 139,
Figure RE-FDA0003146799160000011
dividing the generated sequence into two parts, wherein 72 bits of the former part are placed on a first ofdm symbol, 67 bits of the latter part are placed on a second ofdm symbol, and the time domain sending signal is that the time domain data length is 128:
Figure RE-FDA0003146799160000012
t when the set position is the first ofdm symbolCPIs 10, L ═ 72; t when the set position is the second ofdm symbolCPIs 9, L ═ 67;
step two: the frame structure sent by the air interface is shown in fig. 3;
step three: the frame structure of the synchronization, the time domain signal mapping position of the synchronization sequence is shown in fig. 4;
step four: the correlation verification under the current synchronization sequence configuration can obtain better auto-correlation and cross-correlation characteristics by screening proper u values, and the u values are selected as follows: 71113161720212829303334394146485154889198100106108109110111119120122123126, respectively;
using the above selected u values, the correlation characteristics are shown in fig. 5;
step five: when accessing the ad hoc network, the synchronization detection device user needs to detect all synchronization sequences and determine the user resources that can be currently contacted.
CN202110401737.4A 2021-04-14 2021-04-14 Ad hoc network synchronization system based on OFDM and method thereof Pending CN113225291A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110401737.4A CN113225291A (en) 2021-04-14 2021-04-14 Ad hoc network synchronization system based on OFDM and method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110401737.4A CN113225291A (en) 2021-04-14 2021-04-14 Ad hoc network synchronization system based on OFDM and method thereof

Publications (1)

Publication Number Publication Date
CN113225291A true CN113225291A (en) 2021-08-06

Family

ID=77087210

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110401737.4A Pending CN113225291A (en) 2021-04-14 2021-04-14 Ad hoc network synchronization system based on OFDM and method thereof

Country Status (1)

Country Link
CN (1) CN113225291A (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6993084B1 (en) * 1998-04-14 2006-01-31 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Coarse frequency synchronisation in multicarrier systems
CN101202729A (en) * 2006-07-25 2008-06-18 北京凌讯华业科技有限公司 TDS-OFDM communication system receiver based on LDPC code
CN102868660A (en) * 2012-09-05 2013-01-09 电子科技大学 Downlink transmission synchronization method based on broadband wireless communication system
CN106911601A (en) * 2017-01-05 2017-06-30 深圳市雷克斯托通信有限公司 The main synchronizing sequence detection method and device of a kind of cell searching
CN107171993A (en) * 2017-05-22 2017-09-15 东南大学 Up united carrier synchronization hardware implementation method based on extensive MIMO
CN109802912A (en) * 2019-04-08 2019-05-24 中国人民解放军国防科技大学 Synchronization method, apparatus, device and storage medium for broadband wireless communication system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6993084B1 (en) * 1998-04-14 2006-01-31 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Coarse frequency synchronisation in multicarrier systems
CN101202729A (en) * 2006-07-25 2008-06-18 北京凌讯华业科技有限公司 TDS-OFDM communication system receiver based on LDPC code
CN102868660A (en) * 2012-09-05 2013-01-09 电子科技大学 Downlink transmission synchronization method based on broadband wireless communication system
CN106911601A (en) * 2017-01-05 2017-06-30 深圳市雷克斯托通信有限公司 The main synchronizing sequence detection method and device of a kind of cell searching
CN107171993A (en) * 2017-05-22 2017-09-15 东南大学 Up united carrier synchronization hardware implementation method based on extensive MIMO
CN109802912A (en) * 2019-04-08 2019-05-24 中国人民解放军国防科技大学 Synchronization method, apparatus, device and storage medium for broadband wireless communication system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
陈颖: "OFDM系统时频同步算法的研究与实现", 《中国优秀硕士学位论文全文数据库 (基础科学辑)》 *

Similar Documents

Publication Publication Date Title
WO2021121058A1 (en) Methods for transmitting and receiving sidelink positioning reference signal, and terminal
EP1720310B1 (en) Method and apparatus for multiplexing data and control information in wireless communication systems based on frequency division multiple access
WO2018127202A1 (en) Method and device for transmitting a reference signal
KR101079387B1 (en) Uplink access request in an ofdm communication environment
WO2020147731A1 (en) Communication method and device
US11696143B2 (en) Method and device in communication node for wireless communication
JP2004064793A (en) Orthogonal frequency division multiplex communication method and apparatus adaptive to channel characteristics
US11128508B2 (en) Information transmission method and apparatus in wireless local area network
EP2041940B1 (en) Uplink timing control signal
CN114268530B (en) Signal sending and receiving method, terminal and device
CN108289069B (en) Transmission method, sending end and receiving end of reference signal
CN108540271A (en) A kind of Alamouti transmission methods, wireless communication system suitable for FBMC/OQAM
CN102263722A (en) Method and system for mapping uplink frequency domain resources
CN1953364A (en) A realization method for channel in multicarrier wave system cell
WO2020227866A1 (en) Terminal and sending method
WO2020088637A1 (en) Signal sending method, and terminal
CN102571667A (en) Method and system for power allocation in a transmission system
CN113225291A (en) Ad hoc network synchronization system based on OFDM and method thereof
JP2002261727A (en) Ofdm signal transmitter
CN108429609B (en) Handshake-free channel access method based on NC-OFDM (numerical control-orthogonal frequency division multiplexing) in self-organizing network
CN107896135B (en) Method and equipment in UE (user Equipment) supporting simplified control information and base station
WO2012109930A1 (en) Method, device, and system for transmitting baseband data
US20240224299A1 (en) Methods, devices, and systems for determining synchronization signal raster
KR101486148B1 (en) Method for cancelling inter-subcarrier interference in wireless communication systems and apparatus for performing the same
WO2022062819A1 (en) Symbol application method and communication apparatus

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
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20210806

WD01 Invention patent application deemed withdrawn after publication