CN111865860B - Wireless broadcast time service system based on OFDM technology - Google Patents
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- H04L27/00—Modulated-carrier systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04L27/00—Modulated-carrier systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
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- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
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- H04L27/2673—Details of algorithms characterised by synchronisation parameters
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Abstract
The invention relates to a wireless broadcast time service system based on OFDM technology, which comprises an OFOM system design and a time service signal forwarding network, wherein the OFOM system design comprises a basic parameter baseband, a subcarrier, an OFDM data body, an OFDM cyclic prefix, an OFDM symbol, a modulation mode, FEC coding, a synchronous signal, an OFDM symbol in a signal frame, an OFDM symbol effective subcarrier and frequency domain pilot frequency, and the method comprises the following processing steps: and establishing an OFDM signal frame structure, designing a synchronous signal, designing an OFDM symbol, carrying out FEC spread spectrum processing and carrying out other system submodule processing. The invention provides a wireless broadcast time service system based on an OFDM technology, which not only can complete a communication network for time service signal transmission in a common environment and a complex environment, but also has the characteristics of strong signal coverage, high time service precision and good concurrency, and meets the transmission requirements of time service signals under different conditions.
Description
Technical Field
The invention belongs to the field of digital information transmission, and particularly relates to a wireless broadcast time service system based on an OFDM technology.
Background
High-precision time information plays an increasingly important role in the technical and economic development of the current society, and industries such as communication, electric power, finance and the like can not leave an accurate timing system to realize synchronous and high-efficiency operation. With the wide application and development of time service in these fields, the performance, reliability, and cost of implementation and maintenance of a time service system for realizing accurate time synchronization are gradually more emphasized.
Common time service modes in the market include atomic clocks, navigation satellite time service, short-wave time service, long-wave time service, network time service and the like. Among them, atomic clocks have the highest accuracy, but are expensive and difficult to be widely used. The precision of the navigation satellite time service can reach 20ns, but the limitation is that the satellite signal is weak and is easy to be interfered, especially the navigation satellite time service device cannot work indoors and the like under the environment without the satellite signal, and the connection mode of transmitting the received satellite time service signal or transmitting the satellite time service signal to the time service target device through a wired network is sometimes difficult to be actually operated due to the consideration of various factors such as distance, wiring, obstacles, flexibility of the time service network and the like.
The short-wave time service signal is transmitted by means of reflection of an ionized layer, and as the ionized layer is influenced by factors such as solar black-seed annual variation, seasonal variation, day and night variation and the like, the reflectivity of the ionized layer shows irregular variation, the stability of time signal transmission is greatly influenced, and the short-wave time service receiver cannot perform time service successfully for a long time. The time service precision is only about +/-1 ms, and the time service device cannot be used in some occasions with higher time service precision requirements.
The long-wave time service signal has good anti-interference performance, the time service precision can reach +/-5 us, but the long-wave time service has the limitations of single time service information, incapability of self-service time service and the like. Meanwhile, if the long-wave time service station chain data repetition period is long, the user can be successful in time service after a long time, which is not beneficial to accurate measurement and real-time service.
The network time service technology using the Ethernet as a medium has the advantages of convenience, rapidness and low cost, but the time service precision is low, generally about tens of milliseconds, and the time service precision is changed along with the network structure and the load of the network.
In addition, there are some wireless communication technologies related to time service signals, but basically, a slave initiates a time service application to a master, and the master transmits time service information to the slave through a specific wireless communication system, so that the problem of uncontrollable time delay exists in the process, and the burst time service requirement of a large number of slaves is difficult to support.
OFDM (Orthogonal Frequency Division Multiplexing), which is a multi-carrier transmission method capable of fully utilizing spectrum resources, has good capability of resisting narrowband interference and multipath interference, and is particularly suitable for information transmission requirements in a complex wireless communication environment, and by combining with frame structure design of spread spectrum and a special spreading form, a system can have relatively high sensitivity, and can also play a good communication effect even in an application scene of serious signal fading, such as indoor/underground. The invention fully researches the actual requirement that the time service system can ensure that the time service signal can accurately finish transmission in real time in the environment with serious signal fading such as indoor and the like, and provides a wireless broadcast time service system by combining the characteristics of the OFDM technology, which not only can be used for time service tasks in the common transmission environment, but also can meet the time service requirement in the environment with strong interference or difficult coverage of the common wireless signal.
Disclosure of Invention
The invention provides a wireless broadcast time service system based on an OFDM technology, which not only can complete a communication network for time service signal transmission in a common environment and a complex environment, but also has the characteristics of strong signal coverage, high time service precision and good concurrency, and meets the transmission requirements of time service signals under different conditions.
The technical scheme of the invention is to construct a wireless broadcast time service system based on OFDM technology, which comprises an OFOM system design and a time service signal forwarding network, wherein the OFOM system design comprises a basic parameter baseband, a subcarrier, an OFDM data body, an OFDM cyclic prefix, an OFDM symbol, a modulation mode, FEC coding, a synchronous signal, an OFDM symbol in a signal frame, an OFDM symbol effective subcarrier and a frequency domain pilot frequency, and the wireless broadcast time service system comprises the following processing steps:
1): an OFDM signal frame structure is established, the OFDM system physical layer signal takes a frame as a unit, and each frame is composed of a synchronous signal and 48 OFDM symbols. The time length of one signal frame is 1 second, and the signal interval received by the time service terminal is a fixed whole second length;
the length of the cyclic prefix is greater than the impulse response length of a channel, the baseband sampling rate is 3.2kHz, the subcarrier interval is 100Hz, the length of the OFDM data body is 10ms, the length of the OFDM cyclic prefix is 10ms, the OFDM symbol period is 20ms, the modulation mode is QPSK, the FEC code is LDPC code, the code word length is 576, and the code rate is 1/2;
2): synchronous signal deviceThe synchronous signals are A, A and A * 、Α * Four signal blocks, each containing 32 sample point data, wherein
A＝IFFT{[X 0 ,X 1 ,X 2 ,.......,X 31 ]}＝[x 0 ,x 1 ,x 2 ,.......,x 31 ]Of said [ X ] 0 ,X 1 ,X 2 ,.......,X 31 ]The frequency domain pilot frequency signal is generated by a linear feedback shift register generator, the length of a synchronous signal is 40ms, the number of OFDM symbols in a signal frame is 48, the length of the signal frame is 1s, the number of effective subcarriers of the OFDM symbols is 30, and the frequency domain pilot frequency interval is 5;
3): designing an OFDM symbol, namely expanding the length of an OFDM cyclic prefix to 100% of the length of the OFDM symbol;
4): performing spread spectrum processing on the FEC, wherein the spread spectrum processing method is to repeat 1 LDPC block data for 4 times completely to expand the 1 LDPC block data to 4 times of the original length, and performing spread spectrum processing on an LDPC coding block by using de-spread processing of LDPC decoding soft information at a receiving end, wherein the FEC coding adopts LDPC coding with 576 length;
5): other system sub-module processes including scrambling, FEC encoding, interleaving, pilot frequency and sub-carrier mapping, and the time service information is processed by a binary pseudo-random sequence
And (4) scrambling. />
Generated by a linear feedback shift register, the corresponding generator polynomial is: x is a radical of a fluorine atom 9 +x 4 +1, the initial value of the shift register is 000000001, the linear feedback shift register is reset to the initial value at the start position of each frame, the scrambling code is realized by modulo-2 addition of the input bit information sequence and the binary pseudorandom sequence, and the formula is ^ greater or greater>
Wherein X (i) is bits before scrambling, a (i) is bits after scrambling, and the FEC encoding is to perform F on the bit stream after scramblingEC coding with LDPC coding mode and 1/2 code rate, bit interleaving is adopted for service description information which is subjected to convolutional coding, interleaving is carried out by taking an interleaving block as a unit, and the algorithm is that an input sequence before interleaving is set as ^ and ^ er>
Wherein N is MUX For the length of the interleaved block, the output sequence after interleaving is
V is then n ＝u R(N) />
Wherein p (0) =0,p (i) = mod (5 xp (i-1) + q) s, (i ≠ 0),
q = s/4-1, the time service information of one frame is subjected to bit interleaving according to the algorithm after the spread spectrum of the LDPC block, and the interleaving length N MUX ＝4*N 1 ，N 1 =576, is the LDPC code length.
Preferably, the data byte streams input by the time service information are all in a mode that MSB is in front.
The invention has the beneficial effects that:
1. the GPS time service system is flexibly adaptive to various time service signal sources, can support the forwarding of GPS time service signals, and can also support high-precision atomic clocks or third-party time service signals;
2. the capability of resisting signal fading is particularly enhanced in the process of designing the OFDM system, so that the OFDM system can also complete receiving and demodulation in the environment with strong interference and rapid fading of wireless signals;
3. the time service signal is forwarded in a broadcast mode, a slave machine does not need to initiate time service application, communication delay is avoided, and meanwhile, a large number of concurrent time service requirements can be met;
4. the time length of the signal frame is specially designed to ensure that the time service signal can be received at a fixed time point, and the time delay and the deviation are controllable.
Drawings
Fig. 1 is a physical layer structure diagram of a wireless time service system.
Fig. 2 is a frame structure diagram of a time service signal wireless broadcast system.
Fig. 3 is a diagram of a synchronization signal structure.
Fig. 4 is a linear feedback shift register diagram for generating a synchronization signal.
Fig. 5 is a diagram of a cyclic prefix based synchronization method.
Fig. 6 is a linear feedback shift register for generating scrambling codes.
Fig. 7 is a pilot and subcarrier map.
Fig. 8 is a diagram showing a network arrangement method of a basic time service signal radio broadcasting system.
Fig. 9 is a diagram of a local transfer mode of a time service signal radio broadcasting system.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto. The embodiments of the present invention are not limited to the embodiments described above, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they are included in the scope of the present invention.
Example 1:
as shown in fig. 1 to fig. 9, a wireless broadcast time service system based on OFDM technology includes an OFOM system design and a time service signal forwarding network, and is characterized in that the OFOM system design includes a basic parameter baseband, a subcarrier, an OFDM data block, an OFDM cyclic prefix, an OFDM symbol, a modulation scheme, FEC coding, a synchronization signal, an OFDM symbol in a signal frame, an OFDM symbol effective subcarrier, and a frequency domain pilot frequency, and includes the following processing steps:
1): an OFDM signal frame structure is established, the OFDM system physical layer signal takes a frame as a unit, and each frame is composed of a synchronous signal and 48 OFDM symbols. The time length of one signal frame is 1 second, and the signal interval received by the time service terminal is a fixed whole second length;
2): design of synchronization signal composed of A, A and A * 、Α * Four signal blocks, each containing 32 sample point data, wherein
A＝IFFT{[X 0 ,X 1 ,X 2 ,.......,X 31 ]}＝[x 0 ,x 1 ,x 2 ,.......,x 31 ]Of said [ X ] 0 ,X 1 ,X 2 ,.......,X 31 ]Generated by a linear feedback shift register generator;
3): designing an OFDM symbol, namely expanding the length of an OFDM cyclic prefix to 100% of the length of the OFDM symbol;
4): performing FEC spread spectrum processing, wherein the FEC coding adopts LDPC coding with 576 lengths, and the LDPC coding blocks are subjected to spread spectrum processing;
5): other system sub-module processes including scrambling, FEC encoding, interleaving, pilot frequency and sub-carrier mapping, and the time service information is processed by a binary pseudo-random sequence
And (4) scrambling. />
Generated by a linear feedback shift register, the corresponding generator polynomial is: x is the number of 9 +x 4 +1, the initial value of the shift register is 000000001, the linear feedback shift register is reset to the initial value at the start position of each frame, the scrambling code is realized by modulo-2 addition of the input bit information sequence and the binary pseudorandom sequence, and the formula is ^ greater or greater>
In the formula, X (i) is a bit before scrambling, a (i) is a bit i after scrambling, the FEC coding is to carry out FEC coding on a bit stream after scrambling, the coding mode is LDPC, the code rate is 1/2, the interleaving is carried out by adopting bit interleaving for service description information which is subjected to convolutional coding, the interleaving is carried out by taking an interleaving block as a unit, and the algorithm is that an input sequence before interleaving is set as ^ and ^ before interleaving>
Wherein N is MUX For the length of the interleaved block, the output sequence after interleaving is
V is then n ＝u R(N)
Wherein p (0) =0,p (i) = mod (5 xp (i-1) + q) s, (i ≠ 0),
q = s/4-1, time service information of one frame is subjected to bit interleaving according to the algorithm after being spread according to LDPC block, and the interleaving length N MUX ＝4*N 1 ，N 1 =576, is LDPC code length.
The physical layer signal of the OFDM system is in units of frames, and each frame is composed of one synchronization signal and 48 OFDM symbols. The time length of a signal frame is 1 second, the signal interval received by the time service terminal is a fixed whole second length, so as long as the clock of the transmitting terminal is accurate enough, the error of the time service signal can be compensated at the receiving terminal, and the complexity of the whole system for delay estimation is greatly simplified.
The synchronous signal structure has the characteristics of mobile correlation and central symmetry correlation, is suitable for signal transmission in weak signal and strong interference environments, makes full use of the characteristics, and the receiving end can estimate the synchronous position of the received signal more accurately.
The length of the cyclic prefix is chosen to extend to 100% of the OFDM symbol length. The advantage of this is that, except that the redundant part of the OFDM symbol can be used to the maximum extent to obtain the gain effect equivalent to the spread spectrum of the OFDM symbol, the method introduced in the reference material can also be used to obtain the time domain interval of each OFDM symbol by using the good correlation characteristic between the cyclic prefix and the OFDM data body, and the synchronization performance of the system can be further improved by fully using the characteristic.
The cyclic prefix is the complete copy of the OFDM data body, when the correlation calculation is carried out on the time domain, the correlation peak reaches the maximum value when the sliding window moves to the initial position of the symbol, the initial position of each OFDM symbol can be easily positioned according to the OFDM-based cyclic prefix synchronization algorithm, if the position of the symbol is accumulated by adopting a proper algorithm, the initial position of the OFDM symbol can be accurately positioned even under the environment with serious signal fading, and the method is very valuable for the synchronization estimation of the system.
The FEC coding uses LDPC coding of 576 lengths. The LDPC is a block coding close to the Shannon limit, but because the system aims to be capable of completing the transmission of time service information under extremely low signal strength and is difficult to meet the requirement only by the performance of the coding, the invention carries out spread spectrum processing on the LDPC coding block so that a receiving end can complete limit decoding work by utilizing gain brought by spread spectrum.
The OFDM system parameters can be deduced that 4 LDPC coded blocks are carried by one signal frame.
The sub-carriers carrying actual signals in the OFDM symbols are called effective sub-carriers, and include digital sub-carriers and pilots, the virtual sub-carriers do not carry any signals, and the carrier transmission power is 0.
Time service signal forwarding network interpretation:
firstly, the time service signal wireless broadcast system provided by the invention can be used for a wide-range time service distribution network, transmits a high-performance time service signal broadcast to a plurality of devices needing time service in a certain area, does not cause cost and time delay increase due to excessive devices applying time service, and ensures that time service precision is not lost.
In addition, the time service signal wireless broadcasting system provided by the invention can also be used for receiving the existing time service signal under the condition of local strong interference environment or serious fading of the signal, then broadcasting the time service signal in the environment, and solving the problem of indoor relay of the time service signal.
Example 2:
on the basis of embodiment 1, as shown in fig. 1 to 9, the length of the cyclic prefix is greater than the impulse response length of the channel. The role of cyclic prefix in OFDM systems is mainly to eliminate inter-symbol interference (ISI) and inter-symbol interference (ICI), and generally, the length of cyclic prefix is only required to be longer than the impulse response length of the channel. In the invention, the decoding performance of the system is further improved.
Example 3:
in embodiment 1, as shown in fig. 1 to 9, the baseband sampling rate is 3.2kHz, the subcarrier interval is 100Hz, the OFDM data body length is 10ms, the OFDM cyclic prefix length is 10ms, the OFDM symbol period is 20ms, the modulation scheme is QPSK, the FEC coding is LDPC coding, the codeword length 576, the code rate 1/2, the synchronization signal length is 40ms, the number of OFDM symbols in the signal frame is 48, the signal frame length is 1s, the number of effective subcarriers of the OFDM symbols is 30, and the frequency domain pilot interval is 5.
Example 4:
based on embodiment 1, as shown in fig. 1 to 9, the spreading process is a method of repeating 1 LDPC block data 4 times completely so that 1 LDPC block data is spread to 4 times the original length, and despreading processing using LDPC decoded soft information is performed at the receiving end.
Example 5:
in addition to embodiment 1, as shown in fig. 1 to 9, the data byte streams to which the time service information is input are all in a manner that the MSB precedes.
Claims (2)
1. A wireless broadcast time service system based on OFDM technology comprises OFOM system design and a time service signal forwarding network, and is characterized in that: the OFOM system design comprises a basic parameter baseband, subcarriers, an OFDM data body, an OFDM cyclic prefix, OFDM symbols, a modulation mode, FEC coding, synchronous signals, OFDM symbols in a signal frame, effective subcarriers of the OFDM symbols and frequency domain pilot frequency, and comprises the following processing steps:
1): establishing an OFDM signal frame structure, wherein the physical layer signal of an OFDM system takes a frame as a unit, each frame consists of a synchronous signal and 48 OFDM symbols, the time length of one signal frame is 1 second, and the signal interval received by a time service terminal is a fixed whole second length; the length of the cyclic prefix is greater than the impulse response length of a channel, the baseband sampling rate is 3.2kHz, the subcarrier interval is 100Hz, the length of the OFDM data body is 10ms, the length of the OFDM cyclic prefix is 10ms, the OFDM symbol period is 20ms, the modulation mode is QPSK, the FEC code is LDPC code, the code word length is 576, and the code rate is 1/2;
2): design of synchronous signal composed of A, A and
、/>
four signal blocks, each containing 32 sample point data, where a = IFFT { [ - { ]>
]}=[/>
]Said [>
]The frequency domain pilot frequency signal is generated by a linear feedback shift register generator, the length of a synchronous signal is 40ms, the number of OFDM symbols in a signal frame is 48, the length of the signal frame is 1s, the number of effective subcarriers of the OFDM symbols is 30, and the frequency domain pilot frequency interval is 5;
3): designing an OFDM symbol, namely expanding the length of an OFDM cyclic prefix to 100% of the length of the OFDM symbol;
4): performing spread spectrum processing on the FEC, wherein the spread spectrum processing method is to repeat 1 LDPC block data for 4 times completely to expand the 1 LDPC block data to 4 times of the original length, and performing spread spectrum processing on an LDPC coding block by using de-spread processing of LDPC decoding soft information at a receiving end, wherein the FEC coding adopts LDPC coding with 576 length;
5): other system sub-module processes including scrambling, FEC encoding, interleaving, pilot frequency and sub-carrier mapping, time service information is processed by a binary pseudo-random sequence
Is scrambled and taken out>
Generated by a linear feedback shift register, and the corresponding generator polynomial is: />
The initial value of the shift register is 000000001, the linear feedback shift register is reset to the initial value at the initial position of each frame, the scrambling code is realized by carrying out modulo-2 addition on the input bit information sequence and the binary system pseudorandom sequence, and the formula is ^ 4>
In the formula>
For the bit before scrambling, is asserted>
The bit i after scrambling is adopted as the FEC encoding, the encoding mode is LDPC, the code rate is 1/2, the interleaving adopts bit interleaving for service description information after convolutional encoding, the interleaving is carried out by taking an interleaving block as a unit, and the algorithm is that the input sequence before interleaving is set as ^ er>
In which>
For the length of the interleaved block, the output sequence after interleaving is
Then->
Wherein the content of the first and second substances,
，p(i)＝mod(5×p(i-1)+q)s，/>
，/>
,/>
=/>
the time service information of one frame is spread according to the LDPC block and then carries out bit interleaving according to the algorithm, and the interleaving length->
，/>
And is the LDPC code length.
2. The OFDM technology-based wireless broadcast time service system as claimed in claim 1, wherein the data byte stream of the time service information input is in the MSB-first mode.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1960357A (en) * | 2006-10-20 | 2007-05-09 | 北京泰美世纪科技有限公司 | Multicarrier digital mobile multimedia broadcast system, and digital information transmission method |
| CN104244401A (en) * | 2014-10-16 | 2014-12-24 | 成都微址科技有限公司 | Satellite timing service-based wireless communication method and satellite timing service-based wireless communication device |
| CN105940626A (en) * | 2014-11-06 | 2016-09-14 | Lg电子株式会社 | Method and apparatus for receiving broadcast signal, and method and apparatus for transmitting broadcast signal |
| CN110430155A (en) * | 2016-12-09 | 2019-11-08 | 三星电子株式会社 | The method and apparatus of broadcast singal and channel for system information transmissions |
| CN110557169A (en) * | 2019-07-24 | 2019-12-10 | 西安空间无线电技术研究所 | Low-orbit mobile communication satellite system based on frequency hopping time hopping positioning time service function |
| CN110972252A (en) * | 2018-09-28 | 2020-04-07 | 电信科学技术研究院有限公司 | Signal sending method, waveform configuration method, terminal and network equipment |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050254486A1 (en) * | 2004-05-13 | 2005-11-17 | Ittiam Systems (P) Ltd. | Multi processor implementation for signals requiring fast processing |
| CN102907050B (en) * | 2012-06-06 | 2015-04-08 | 华为技术有限公司 | Multiple access method, device and system |
| KR102302600B1 (en) * | 2014-08-07 | 2021-09-15 | 원 미디어, 엘엘씨 | Method for dynamic configuration of a flexible orthogonal frequency division multiplexing phy transport data frame |
-
2020
- 2020-06-29 CN CN202010605491.8A patent/CN111865860B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1960357A (en) * | 2006-10-20 | 2007-05-09 | 北京泰美世纪科技有限公司 | Multicarrier digital mobile multimedia broadcast system, and digital information transmission method |
| CN104244401A (en) * | 2014-10-16 | 2014-12-24 | 成都微址科技有限公司 | Satellite timing service-based wireless communication method and satellite timing service-based wireless communication device |
| CN105940626A (en) * | 2014-11-06 | 2016-09-14 | Lg电子株式会社 | Method and apparatus for receiving broadcast signal, and method and apparatus for transmitting broadcast signal |
| CN110430155A (en) * | 2016-12-09 | 2019-11-08 | 三星电子株式会社 | The method and apparatus of broadcast singal and channel for system information transmissions |
| CN110972252A (en) * | 2018-09-28 | 2020-04-07 | 电信科学技术研究院有限公司 | Signal sending method, waveform configuration method, terminal and network equipment |
| CN110557169A (en) * | 2019-07-24 | 2019-12-10 | 西安空间无线电技术研究所 | Low-orbit mobile communication satellite system based on frequency hopping time hopping positioning time service function |
Non-Patent Citations (4)
| Title |
|---|
| OFDM技术在BPM短波数据调制中的应用探讨;袁江斌 等;《时间频率学报》;20191231;全文 * |
| RP-170376 "Status Report of Study on New Radio Access Technology";NTT DOCOMO等;《3GPP tsg_ran\TSG_RAN》;20170228;全文 * |
| Signal to interference ratio (SIR) analysis and interference cancellation in MIMO OFDM systems with carrier frequency and timing offsets;N. Sreekanth et.al.;《Fourth International Conference on Advances in Recent Technologies in Communication and Computing (ARTCom2012)》;20150420;全文 * |
| 低压电力线载波时间同步信道编码技术研究;吕博云;《中国优秀硕士学位论文全文数据库 (信息科技辑) 》;20150115;全文 * |
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