Frequency domain arrival detection method of orthogonal frequency division multiplexing system

Abstract

The invention discloses a frequency domain arrival detection method of an orthogonal frequency division multiplexing system. A frequency domain synchronous transmitting unit adopts two frequency domain pseudorandom sequences with identical length but different phases, a zero is respectively compensated to each pseudorandom sequence to obtain a pseudorandom expanded sequence, then rapid Fourier inverse transformation operation is carried out on the pseudorandom expanded sequences to obtain time domain sequences, and then the two time domain sequences are cascaded to obtain a synchronous pilot training sequence. A frequency domain synchronous receiving unit adopts a time window with a length being identical to that of one pseudorandom expanded sequence, rapid Fourier transformation operation is carried out on data inside the window, then the data is correlated with a known local pseudorandom expanded sequence after being subjected to peak clipping and amplitude limitation processing, and the signal arrival is judged by utilizing excellent autocorrelation property of the pseudorandom sequence and simultaneously considering a threshold and position-based detection method. Due to the adoption of the frequency domain arrival detection method of the orthogonal frequency division multiplexing system, interference of a single tone, narrow band and the like can be effectively resisted, and reliable signal arrival detection can also be realized under a severe channel condition.

Description

technical field

[0001] The invention relates to the technical field of data transmission in a mobile communication system, in particular to a signal transmission and arrival detection method based on frequency domain frame synchronization in an orthogonal frequency division multiplexing system. Background technique

[0002] With the development of digital signal processing technology and high-speed devices, Orthogonal Frequency Division Multiplexing (OFDM) technology is more and more widely used in communication systems. This special multi-carrier transmission method, due to the orthogonality between the sub-carriers, can allow the spectrum between the sub-channels to overlap each other, can maximize the use of spectrum resources and reduce the information rate of the sub-channels, so it has good performance. Anti-noise and anti-multipath interference capabilities, suitable for high-speed data transmission in frequency selective fading channels.

[0003] The main goal and t...

Examples

Embodiment

[0047] combine figure 2 , the specific steps of the frequency domain synchronization sending unit are:

[0048] 1) First use the pseudo-random sequence generator (101) corresponding to the original polynomial 1 with an order of N to generate a segment with a length of 2 N The PN sequence of -1 is mapped into a bipolar PN sequence with a value of +1 and -1 through the mapper (102), and a 0 is added at the beginning of the sequence to obtain a length of 2 N The sequence P1.

[0049] 2) Then use the pseudo-random sequence generator (104) corresponding to the original polynomial 2 with order N to generate a length of 2 N The PN sequence of -1 is mapped into a bipolar PN sequence with a value of +1 and -1 through the mapper (105), and a 0 is added at the beginning of the sequence to obtain a length of 2 N The sequence P2.

[0050] 3) Send the sequences P1 and P2 into the IFFT modules (103, 106) respectively to obtain the sequences P3 and P4, and then concatenate the sequences ...

technical field

[0001] The invention relates to the technical field of data transmission in a mobile communication system, in particular to a signal transmission and arrival detection method based on frequency domain frame synchronization in an orthogonal frequency division multiplexing system. Background technique

[0002] With the development of digital signal processing technology and high-speed devices, Orthogonal Frequency Division Multiplexing (OFDM) technology is more and more widely used in communication systems. This special multi-carrier transmission method, due to the orthogonality between the sub-carriers, can allow the spectrum between the sub-channels to overlap each other, can maximize the use of spectrum resources and reduce the information rate of the sub-channels, so it has good performance. Anti-noise and anti-multipath interference capabilities, suitable for high-speed data transmission in frequency selective fading channels.

[0003] The main goal and t...

Examples

Embodiment

[0047] combine figure 2 , the specific steps of the frequency domain synchronization sending unit are:

[0048] 1) First use the pseudo-random sequence generator (101) corresponding to the original polynomial 1 with an order of N to generate a segment with a length of 2 N The PN sequence of -1 is mapped into a bipolar PN sequence with a value of +1 and -1 through the mapper (102), and a 0 is added at the beginning of the sequence to obtain a length of 2 N The sequence P1.

[0049] 2) Then use the pseudo-random sequence generator (104) corresponding to the original polynomial 2 with order N to generate a length of 2 N The PN sequence of -1 is mapped into a bipolar PN sequence with a value of +1 and -1 through the mapper (105), and a 0 is added at the beginning of the sequence to obtain a length of 2 N The sequence P2.

[0050] 3) Send the sequences P1 and P2 into the IFFT modules (103, 106) respectively to obtain the sequences P3 and P4, and then concatenate the sequences ...

Images