CN102685067B - Nonlinear rainfall attenuation channel multiple amplitude and phase shift keying (MAPSK) optimal modulation method - Google Patents

Abstract

The invention relates to a nonlinear rainfall attenuation channel multiple amplitude and phase shift keying (MAPSK) optimal modulation method, which is characterized by comprising the following steps of: establishing a Mie-scattering-based unit nonlinear attenuated rainfall model, simulating a constellation diagram of a standard MAPSK constellation passing through a rainfall attenuation channel according to the nonlinear attenuated rainfall model, calculating a relative radius rhok and a minimum inter-ring distance dringi,ringi+1 of the standard MAPSK constellation, and constructing an MAPSK constellation diagram by using the relative radius rho'k=min(A'r*rhok, dringi,ringi+1) of the optimized constellation. According to the method, the influence of the nonlinear rainfall attenuation channel on MAPSK modulation can be effectively resisted, and the bit error rate performance of the optimized MAPSK constellation can be reduced by an order of magnitude.

Description

A kind of non-linear rain channel-MAP SK that declines optimizes modulator approach

Technical field

The present invention relates to a kind of non-linear rain decline channel-MAP SK optimize modulator approach, for satellite communication.

Background technology

Adopting in the high band satellite communication of MAPSK modulation, the impact that non-linear rain declines is very serious, and to the non-linear rain of satellite channel, the decline research of channel is to ensure one of key technology of satellite channel signal normal transmission.

In wideband satellite communication, the modes that adopt uplink and downlink links to adopt different frequencies reduce the rain nonlinear impact that declines more, although the method can reduce the distortion of signal, can not ensure effective utilization of frequency spectrum.

Summary of the invention

The technical problem solving

For fear of the deficiencies in the prior art part, the present invention propose a kind of non-linear rain decline channel-MAP SK optimize modulator approach, can effectively reduce the impact that declines of non-linear rain in satellite transmission process, realize MAPSK and be modulated at the non-linear rain channel that declines and descend normal communications.

Technical scheme

A kind of non-linear rain channel-MAP SK that declines optimizes modulator approach, it is characterized in that step is as follows:

Step 1: set up the unit nonlinear attenuation rainfall model based on Mie scattering wherein R _xrepresent rate of rainall, m, n represents the polarization decay coefficient relevant to weather, R _xwith m, the value of n is by obtaining in local meteorological statistics data;

Step 2: the unit nonlinear attenuation rainfall model of setting up according to step 1, the planisphere that standard MAPSK constellation is declined after channel by rain carries out emulation, reads the deviant d of each constellation point from simulation result ₁, d ₂... d _n, n represents the number of constellation points of MAPSK, calculates rain and declines MAPSK constellation affected to A ' _r:

Step 3: the relative radius ρ that calculates standard MAPSK constellation _kwith minimum ring spacing d _{ringi, ringi+1}, wherein n ₁represent counting on APSK the 1st ring, N _krepresent counting on k annulus of APSK, $d_{\mathrm{ringi},\mathrm{ringi}+1}=r_1\sqrt{{{\mathrm{\ρ}}_i}^2+{{\mathrm{\ρ}}_{i+1}}^2-2{\mathrm{\ρ}}_i{\mathrm{\ρ}}_{i+1}\cos \mathrm{\θ}},$ $r_1=\sqrt{1/(N_1+N_2{{\mathrm{\ρ}}_1}^2+...N_n{{\mathrm{\ρ}}_n}^2)},$ θ＝π/N _i-π/N ₁；

Step 4: to optimize the relative radius ρ ' of rear constellation _kbuild MAPSK planisphere, described ρ ' _k=min (A ' _r× ρ _k, d _{ringi, ringi+1}).

Beneficial effect

The non-linear rain of one that the present invention the proposes channel-MAP SK that declines optimizes modulator approach, can effectively resist the impact of channel on MAPSK modulation that decline of non-linear rain, and the error performance of the MAPSK constellation after optimization can reduce approximately order of magnitude.

Brief description of the drawings

Fig. 1: the rain nonlinear model that declines

Fig. 2: 4-12APSK standard constellation

The constellation that Fig. 3: standard 4-12APSK declines after non-linear through rain

Fig. 4: the 4-12APSK constellation of optimization and standard 4-12APSK constellation comparison diagram

Fig. 5: the constellation that the 4-12APSK constellation of optimization declines after non-linear through rain

Performance Ratio before and after Fig. 6: 4-12APSK optimizes

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

The polarization decay Coefficient m of rainfall decline, n is known as 0.187 and 1.021.MAPSK adopts the 4-12APSK planisphere signal of optimizing, and carries out emulation comparison with the MAPSK signal of standard, observes their bit error rate performance.

According to the present invention, its implementation process is as follows:

1) calculate the needed all parameters of rainfall decline and be respectively m=0.817, n=1.021, according to the unit nonlinear attenuation rainfall model based on Mie scattering calculate rainfall decline model as shown in Figure 1.

2) planisphere standard MAPSK constellation being declined after channel by rain carries out emulation, reads the deviant d of each constellation point from simulation result ₁, d ₂... d _n, n represents the number of constellation points of MAPSK, calculates rain and declines MAPSK constellation affected to A ' _r: ${A_r}^{\′}=\frac{d_1+d_2+...d_n}{n};$

3) the relative radius ρ of calculating standard MAPSK constellation _kwith minimum ring spacing d _{ringi, ringi+1}, wherein n ₁represent counting on APSK the 1st ring, N _krepresent counting on k annulus of APSK, $d_{\mathrm{ringi},\mathrm{ringi}+1}=r_1\sqrt{{{\mathrm{\ρ}}_i}^2+{{\mathrm{\ρ}}_{i+1}}^2-2{\mathrm{\ρ}}_i{\mathrm{\ρ}}_{i+1}\cos \mathrm{\θ}},$ $r_1=\sqrt{1/(N_1+N_2{{\mathrm{\ρ}}_1}^2+...N_n{{\mathrm{\ρ}}_n}^2)},$ θ＝π/N _i-π/N ₁；

4) to optimize the relative radius ρ ' of rear constellation _k=min (A ' _r× ρ _k, d _{ringi, ringi+1})=be 2.75, declines the 4-12APSK constellation signal loading after optimizing in channel model to rain, relatively their bit error rate performance, and the result obtaining is as shown in Figure 6.Final conclusion can find out from figure that 4-12APSK constellation modulator approach can well realize the performance that anti-rain declines.4-12APSK constellation after optimization can well be resisted the impact that rain declines, with 1) Performance Ratio that declines of the anti-rain of MAPSK constellation of standard is as Fig. 2, and 3,4, shown in 5.

Claims (1)

1. Non-linear rain decline channel-MAP SK optimize a modulator approach, it is characterized in that step is as follows:

   Step 1: set up the unit nonlinear attenuation rainfall model based on Mie scattering , wherein R _xrepresent rate of rainall, m, l represents the polarization decay coefficient relevant to weather, R _xwith m, the value of l is by obtaining in local meteorological statistics data;

   Step 2: the unit nonlinear attenuation rainfall model of setting up according to step 1, the planisphere that standard MAPSK constellation is declined after channel by rain carries out emulation, reads the deviant d of each constellation point from simulation result ₁, d ₂... d _n, n represents the number of constellation points of MAPSK, calculates the A that affects that rain declines on MAPSK constellation _r':

   Step 3: the relative radius ρ that calculates standard MAPSK constellation _kwith minimum ring spacing d _{ringk, ringk+1}, wherein n ₁represent counting on APSK the 1st ring, N _krepresent counting on k annulus of APSK, $d_{\mathrm{ringk},\mathrm{ringk}+1}=r_1\sqrt{{{\mathrm{\ρ}}_k}^2+{{\mathrm{\ρ}}_{k+1}}^2-2{\mathrm{\ρ}}_k{\mathrm{\ρ}}_{k+1}\cos \mathrm{\θ}},r_1=\sqrt{1/(N_1+N_2{{\mathrm{\ρ}}_1}^2+...N_k{{\mathrm{\ρ}}_k}^2)}$ ，θ＝π/N _k-π/N ₁；

   Step 4: to optimize the relative radius ρ of rear constellation _k' structure MAPSK planisphere, described ρ _k'=min (A _r' × ρ _k, d _{ringk, ringk+1}).