OFDM frequency synchronous method based on training sequence
A training sequence and frequency synchronization technology, applied in the field of communications, can solve the problems of decreased data transmission efficiency, low energy efficiency of transmitted data, and insignificant peak correlation at the receiving end.
Inactive Publication Date: 2009-12-16
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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[0008] However, the above-mentioned OFDM synchronization design methods have shortcomings. The disadvantage of method ① is that the correlation peak at the receiving end is not obvious, and the frequency offset estimation range is only 1 / 2 of the subcarrier spacing of the OFDM system.
The disadvantage of method ② is that the training sequence and OFDM raw data are in the form of time division (or frequency division) multiplexing, which causes a decrease in data transmission efficiency
The disadvantage of method ③ is that the training sequence interferes too much with the data, and the energy efficiency of transmitting data is low
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[0032] The implementation steps of this patent under a specific OFDM configuration are given below. It should be noted that the parameters in the following examples do not affect the generality of this patent.
[0033] It is assumed that the OFDM useful symbol length is N=4096, and the guard interval length is G=1024. The training sequence chooses a CAZAC sequence with good periodic correlation characteristics and constant amplitude characteristics.
[0034] At the transmitting end: perform power normalization processing on the training sequence signal with a useful length of N and the OFDM data signal with a useful length of N, so that the power of the training sequence and OFDM data are ρ and 1-ρ respectively; then the training The sequence signal and the OFDM signal are superimposed at the transmitter, and then transmitted to the channel after adding a protection prefix. Before frequency synchronization processing, we assume that time synchronization has been achieved, tha...
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The invention discloses a new OFDM frequency synchronization method based on training sequence. The sending end superimposes the training sequence on the OFDM useful data, and the receiving end uses the correlation between the received signal and the known training sequence to perform the frequency coarse synchronization operation, and at the same time uses the cyclic prefix to perform the first fine synchronization of the frequency; conducts suppression of OFDM data pair training The interference operation reconstructs a more accurate training sequence at the receiving end, and then performs the second frequency fine synchronization. This synchronization method not only overcomes the shortcoming of the traditional frequency synchronization method based on the cyclic prefix, but also greatly suppresses the interference of the training sequence on OFDM data by the traditional frequency synchronization method based on the training sequence, so that the training sequence can be well The relevant characteristics of the frequency synchronization can be obtained better.
Description
technical field [0001] The invention belongs to the field of communication technology, in particular to a training sequence-based frequency synchronization method in the communication technology. Background technique [0002] OFDM has attracted more and more attention due to its high data transmission rate, strong anti-multipath interference ability, and high spectrum efficiency. It has been successfully applied to wired and wireless communications. Such as: ADSL (Asymmetric Digital Subscriber Line), Wireless LAN, DAB (Digital Audio Broadcasting), DVB, IEEE802.11a and HyperLAN / 2. In the IEEE802.16 currently being formulated, OFDM technology is also involved in a large number. OFDM, a new modulation technique, can also be applied to a new generation of mobile communication systems. The use of OFDM technology will greatly improve the transmission data rate and spectrum efficiency of the new generation of mobile communication systems, and has a good ability to resist multipa...
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IPC IPC(8): H04J11/00H04J1/00H04L7/02H04L7/00H04L27/26
Inventor宋丽英唐友喜赵宏志李少谦
OwnerUNIV OF ELECTRONICS SCI & TECH OF CHINA