First, the main technical analysis of 4G technology

1, OFDM analysis

OFDM (Orthogonal Frequency Division Multiplexing) technology is an intermittent multi-tone technology, which can synthesize single signals with different frequencies, thus realizing signal transmission. This technology can also realize signal transmission function in time under strong interference, so it is often used in media with poor anti-interference ability.

2. Time domain and frequency domain are parallel.

When OFDM is used for transmission, it can be used in different devices, even in different time and frequency domains, and signals in different time domains can be used in the same power grid. Two-way transmission between signals is realized through the power grid, and frequency errors will occur in the initial stage of OFDM symbols when signals are received. Because of the oscillator, a synchronization sequence can be formed in the synchronization data transmitted by the power grid. Then all channels are transmitted through unified equipment, which realizes the algorithm of time synchronization of all unified signals, reduces the error caused by oscillator failure, and can simulate the range of each frequency in the receiver and estimate the value.

3. Information estimation

When estimating information, it is to analyze the physical communication channel and input signal, so as to conduct qualitative research. Signal estimation is to send signals between receiving antennas and then make them respond to frequency.

4. Reduce the peak-to-average power ratio

LMMSE (linear minimum mean square error estimation) is the best estimator. Its principle is to analyze the singular value of LS, which will not reduce the performance of the estimator, and it uses the simplest algorithm. But its disadvantage is that the signal needs to be verified before passing through each path, and the correlation matrix should be constructed by using information.

Step 5 keep balance

With the continuous development of communication technology, 3G technology has become the dominant technology. Based on the development of 3G technology, this paper analyzes the key technologies and existing problems of 4G technology, and uses equalizer to ensure that the length of CP can be reduced, thus improving the complexity of the system and the efficiency of frequency band utilization.

6. Advantages of 6.OFDM

Now, more and more attention has been paid to OFDM technology, and its advantages are obvious to all. It can make full use of the frequency spectrum, and the utilization efficiency is twice that of the traditional serial system. Moreover, OFDM signals realize the overlapping of carriers, and it is easier to reach the limit when using spectrum. Moreover, OFDM technology has strong anti-fading ability, and can transmit information to different carriers, so that information can be transmitted on each carrier.

Second, the application characteristics of 4G technology

4G technology can fully reflect its advantages in application, but there are also some problems, which should be treated dialectically when using 4G technology.

2. Advantages of1OFDM in the application of orthogonal frequency division multiplexing technology

Now, DSP technology has developed rapidly. In OFDM system, each communication channel can be transformed rapidly, so the algorithm of communication technology data can be reduced to a certain extent, so that the data can use simple algorithms, improve the reliability of operation and be more efficient in processing data.

2.2 shortcomings of OFDM when using orthogonal frequency division multiplexing technology

It has PAPR to some extent, and it is in the peak period. The signal power is relatively large, which is prone to signal distortion. When communication is realized, it must be in a large linear range and sensitive to frequency offset, which is easy to cause the problem of not receiving signals.

Third, the conclusion

Now, people have entered the era of communication. The development of 4G technology has realized the application of wireless network. Communication technology is often used in people's lives, which can improve people's quality of life and work efficiency. The application of 4G technology realizes the high-speed transmission of signals, which shows unparalleled advantages. Through high-speed transmission, the coding errors of terminal signals are reduced and the transmission characteristics are estimated. It can make full use of the frequency spectrum, with high efficiency, and is a traditional serial.

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