阅读说明：本技术 一种降低峰平比的信道压缩方法 (A kind of channel shortening method reducing peak-to-average ratio ) 是由 谢哲 张宏滔 朱小辉 王超 周武 于 2019-08-01 设计创作，主要内容包括：本发明公开了一种降低峰平比的信道压缩方法,在发射端,让待发的信号经过一个冲激响应为信道探针信号的滤波器,实现信号峰平比降低；在接收端,利用多通道信道自适应聚焦技术压缩信道,降低信道多途扩展对通信信号的影响,提高通信速率。(The invention discloses a kind of channel shortening methods for reducing peak-to-average ratio to allow signal pending to pass through the filter that an impulse response is channel probe signals in transmitting terminal, realizes signal peak-to-average than reducing；Channel mostly influence of the way extension to signal of communication is reduced, traffic rate is improved using multichannel channel self-adapting focusing technology compression channel in receiving end.)

1. a kind of channel shortening method for reducing peak-to-average ratio, it is characterised in that: in transmitting terminal, allow signal pending by a punching Swash the filter that response is channel probe signals, realizes signal peak-to-average than reducing；In receiving end, multichannel channel self-adapting is utilized Focusing technology compression channel reduces channel mostly influence of the way extension to signal of communication.

2. the channel shortening method according to claim 1 for reducing peak-to-average ratio, it is characterised in that: the transmitting terminal, transmitting Emitted using simple sund source:

(1) source information is loaded on preset subcarrier；

(2) (1) step processing result is subjected to inverse Fourier transform；

(3) behind (2) step processing result, protection interval is added, i.e. one section complete zero of blank is raw using carrier modulation At original underwater sound ofdm signal x₀(t)；

(4) one section of linear FM signal p (t) is generated, as channel probe signals, p (t) frequency bandwidth covers x₀(t)；

(5) by x₀(t) filter for being p (t) by an impulse response generates and improves underwater sound ofdm signal x (t)；

(6) transmitting signal y (t) is generated, successively includes: p (t), one section of blank, x (t), by y (t) by D/A conversion and power It is emitted in water after amplification.

3. the channel shortening method according to claim 1 for reducing peak-to-average ratio, it is characterised in that: the receiving end receives Received using more array elements, array element number 1,2,3 ..., J；

(1) demodulated, synchronize after, obtain j-th array element and receive signal y_r(t), y_rIt (t) include received probe signals p_r(t) With received improvement underwater sound ofdm signal x_r(t)；

(2) by y_r(t) it is sent into channel shortening processor to be handled, obtains result z_j(t)；

(3) by the z in each channel_j(t) it is added and obtains z (t), then deprotection interval, Doppler effect correction, Fu are successively carried out to z (t) In leaf transformation, channel estimation and equalization, finally obtain decoding result.

4. the channel shortening method according to claim 3 for reducing peak-to-average ratio, it is characterised in that: in the step (2) Specific steps are as follows: (a) is from y_r(t) p is intercepted in_r(t) and x_r(t)；(b) by p_r(t) time overturning is carried out to handle to obtain p_r(-t)； (c) by x_rIt (t) is p by an impulse response_rThe filter of (- t) generates z_j(t)。

Technical field

The present invention relates to water sound communication technique, mainly a kind of channel shortening method for reducing peak-to-average ratio.

Background technique

With the development of Marine Sciences and ocean development, water sound communication technique increasingly becomes research emphasis, wherein high speed water Sound communication mainstream technology underwater sound ofdm communication method has become research hotspot.

The advantages of underwater sound ofdm communication technology, is bandwidth availability ratio height, compared to underwater sound spread-spectrum communication technology, underwater sound frequency Key control technology is moved, traffic rate greatly improves.But underwater sound ofdm communication technology also has the technological deficiency of its own: the 1. underwater sound There are peak-to-average ratio (Peak Average Rate) biggish defects for OFDM technology.This leads to underwater sound communication system transmitter The linear dynamic range of the power amplifier at end must be very wide in range.If the dynamic range of amplifier is not able to satisfy the change of signal Change, then can make signal distortion, destroy the orthogonality between each sub-carrier signal, degrading communication performance.2. underwater sound OFDM technology Intersymbol interference (ISI) caused by overcoming underwater acoustic channel mostly way to extend by the way that protection interval is added between symbols and intercarrier are dry (ICI) is disturbed, but when mostly extending serious on the way, the length needs of protection interval are increase accordingly, this causes traffic rate to decline.

Summary of the invention

It is an object of the invention to overcome the shortcomings of the prior art, and provide a kind of channel shortening for reducing peak-to-average ratio Method, this method can not only reduce underwater sound ofdm signal peak-to-average ratio, but also can improve traffic rate with compression channel.

The object of the present invention is achieved by the following technical solutions.A kind of channel shortening method reducing peak-to-average ratio, In transmitting terminal, signal pending is allowed to pass through the filter that an impulse response is channel probe signals, realizes signal peak-to-average than drop It is low；Channel mostly way extension is reduced to signal of communication using multichannel channel self-adapting focusing technology compression channel in receiving end It influences.

Further, the transmitting terminal, transmitting are emitted using simple sund source:

(1) source information is loaded on preset subcarrier；

(2) (1) step processing result is subjected to inverse Fourier transform；

(3) behind (2) step processing result, protection interval, i.e. one section complete zero of blank, using carrier wave tune are added System, generates original underwater sound ofdm signal x₀(t)；

(4) one section of linear FM signal p (t) is generated, as channel probe signals, p (t) frequency bandwidth covers x₀ (t)；

(5) by x₀(t) filter for being p (t) by an impulse response generates and improves underwater sound ofdm signal x (t)；

(6) generate transmitting signal y (t), successively include: p (t), one section of blank, x (t), by y (t) by D/A conversion and It is emitted in water after power amplification.

Further, the receiving end is received and is received using more array elements, array element number 1,2,3 ..., J；

(1) demodulated, synchronize after, obtain j-th array element and receive signal y_r(t), y_rIt (t) include received probe signals p_r(t) and received improvement underwater sound ofdm signal x_r(t)；

(2) by y_r(t) it is sent into channel shortening processor to be handled, obtains result z_j(t)；

(3) by the z in each channel_j(t) it is added and obtains z (t), then successively carry out deprotection interval, Doppler's benefit to z (t) It repays, Fourier transformation, channel estimation and equalization, finally obtains decoding result.

Preferably, the specific steps in the step (2) are as follows: (a) is from y_r(t) p is intercepted in_r(t) and x_r(t)；(b) will p_r(t) time overturning is carried out to handle to obtain p_r(-t)；(c) by x_rIt (t) is p by an impulse response_rThe filter of (- t), it is raw At z_j(t)。

The invention has the benefit that the present invention is in transmitting terminal, allowing signal pending to pass through an impulse response is channel The filter of probe signals realizes signal peak-to-average than reducing.Simultaneously in receiving end, multichannel channel self-adapting focusing technology is utilized Compression channel reduces channel mostly influence of the way extension to signal of communication, improves traffic rate.

Detailed description of the invention

Fig. 1 is that OFDM System for Underwater Acoustic emits block diagram；

Fig. 2 is not have the ofdm signal peak-to-average ratio complementation Cumulative Distribution Function of transmissive wave and transmissive wave to compare figure；

Fig. 3 receives block diagram for the OFDM System for Underwater Acoustic of mentioned method；

Fig. 4 is channel shortening processor；

Fig. 5 is lake examination estimation channel；

Fig. 6 is that the R (t) that data calculate and decoding planisphere are tried in lake.

Specific embodiment

Below in conjunction with drawings and examples, the present invention will be described in detail:

Underwater sound ofdm signal centre frequency 3kHz in the present embodiment, bandwidth 2.4kHz, sample rate 48kHz, sub-carrier number Amount is K=256, and 1 OFDM symbol length is 106ms, and it is 26.5ms that the length of protection interval, which is the 1/4 of OFDM symbol,.Line Property average frequency 3kHz, bandwidth 2.4kHz, pulsewidth 256ms.The block diagram of transmitting terminal emits as shown in Figure 1, in transmitting terminal Emitted using simple sund source:

(1) by source information d_kIt is loaded on preset subcarrier and obtains X (f), i.e. X (f)=[d₁,d₂,...,d₂₅₆]；

(2) X (f) progress inverse Fourier transform is obtainedI.e.

(3) InBelow, protection interval is added, i.e. one section complete zero of blank generates initial condition using carrier modulation Sound ofdm signal x₀(t)；

(4) one section of linear FM signal p (t) is generated, as channel probe signals, because of p (t) and x₀(t) it is Centre frequency 3kHz, bandwidth 2.4kHz, so p (t) frequency bandwidth covers x₀(t)；

(5) by x₀(t) filter for being p (t) by an impulse response generates and improves underwater sound ofdm signal x (t), i.e. x (t)=x₀(t) * p (t), Fig. 2 are underwater sound ofdm signal (the i.e. x for not having transmissive wave and transmissive wave₀(t) tired with x (t)) peak-to-average ratio complementation Score cloth function compares figure, as shown, 10^-2Place, the peak-to-average ratio of transmissive wave are smaller than the peak-to-average ratio for not having transmissive wave about 0.3dB illustrates that underwater sound ofdm signal peak-to-average ratio has dropped after filtering processing；

(6) it generates transmitting signal y (t), successively includes: p (t), one section of blank, x (t), i.e. y (t)=[p (t), 0, 0 ..., 0, x (t)], y (t) is emitted in water after D/A conversion and power amplification；

The block diagram of receiving end is received and is received using more array elements as shown in figure 3, in receiving end, array element number 1,2,3 ..., J:

(1) demodulated, synchronize after, obtain j-th array element and receive signal y_r(t), y_rIt (t) include received probe signals p_r(t) and received improvement underwater sound ofdm signal x_r(t), wherein p_r(t)=p (t) * h_j(t), x_r(t)=x (t) * h_j(t)=x₀ (t)p(t)h_j(t), h_j(t) the channel impulse response function of array element is received to j-th for sound source；

(2) by y_r(t) it is sent into channel shortening processor (such as Fig. 4) to be handled, obtains result z_j(t), specific steps are as follows: (a) from y_r(t) p is intercepted in_r(t) and x_r(t)；(b) by p_r(t) time overturning is carried out to handle to obtain p_r(- t), then p_r(- t)=p (- t)*h_j(-t)；(c) by x_rIt (t) is p by an impulse response_rThe filter of (- t) generates z_j(t), then z_j(t)=x_r(t)* p_r(- t)=x₀(t)*p(t)*h_j(t)*p(-t)*h_j(-t)；

(3) by the z in each channel_j(t) it is added and obtains z (t), then

It enablesThen z (t)=x₀(t) * R (t), it is seen that R (t) can be equivalent For the channel that original underwater sound ofdm signal passes through, because the auto-correlation function of sequence is in " unimodal " shape, R (t) compares h_j(t) It is compressed, deprotection interval, Doppler effect correction, Fourier transformation, channel estimation and equalization is successively finally carried out to z (t), finally Obtain decoding result.When Fig. 5 is that certain lake is tried, battle array is received using 8 yuan and receives the channel that signal is estimated, channel mostly way extends When about 120ms, Fig. 6 are multiple array element signals (respectively 1 array element, 2 array elements, 4 array elements and 8 array elements) merging treatment The R (t) and corresponding decoding constellation figure being calculated, it is seen that more ways of R (t) extend within 7ms, and channel is compressed, and And when 8 array element signals merging treatments, planisphere is clear, and decoding performance is good.

It is understood that it will be understood by those skilled in the art that being subject to technical solution of the present invention and inventive concept It all should fall within the scope of protection of the appended claims of the present invention with replacement or change.