Mimo wireless communication is based on the part decision threshold method to set up of signal-to-noise ratio (SNR) estimation
Technical field
The present invention relates to multi-antenna wireless communication transmission method, especially mimo wireless communication is based on the part decision threshold method to set up of signal-to-noise ratio (SNR) estimation.
Background technology
At present, part decision method in patent mimo wireless communication receiver interference cancellation techniques, application number: the foundation of the part judgement in 2012101400375 is threshold value ε, and the span of this threshold value is 0 < ε < 1, and for different modulation systems, threshold value needs adjustment, simultaneously, for low signal-to-noise ratio and high s/n ratio, threshold value also will adjust, in above-mentioned patent, threshold value gives scope, concrete numerical value is given in embodiment, under not being given in low signal-to-noise ratio and high s/n ratio condition, how value is carried out to this threshold value.Under actual conditions, high s/n ratio, noise power is little, and the possibility of erroneous judgement is little, and the decision statistics that can carry out hard decision wants many, low signal-to-noise ratio, noise power is large, and the possibility of erroneous judgement is large, adjudicates as little as possible to decision statistics, so the selection principle how obtaining threshold value according to signal to noise ratio and modulation system is the technical issues that need to address.
Summary of the invention
The object of the invention is for overcoming above-mentioned the deficiencies in the prior art, providing a kind of mimo wireless communication based on the part decision threshold method to set up of signal-to-noise ratio (SNR) estimation.
For achieving the above object, the present invention adopts following technical proposals:
Mimo wireless communication is based on the part decision threshold method to set up of signal-to-noise ratio (SNR) estimation, and the method comprises: estimate signal to noise ratio according to the coordinate of decision statistics and constellation coordinate; According to the signal to noise ratio estimated and modulation system number, the scope to threshold value is arranged.
Specifically comprise the following steps:
On planisphere, divide the hard decision region of decision statistics in advance, wherein unique corresponding one of each hard decision region transmits, and is called constellation point.According to the hard decision region that the system number of QAM modulation divides, each hard decision region is with dotted line or reference axis for border, and the black circle in each hard decision region is constellation point corresponding to this hard decision region.Suppose that decision statistics constellation point in planisphere is mapped as x, coordinate is (I
x, Q
x), belonging to x, the constellation point coordinate in hard decision region is (I
d, Q
d).
Receiving terminal estimates the signal to noise ratio of decision statistics x in accordance with the following steps:
Step one: determine the hard decision region belonging to decision statistics y, using constellation point D corresponding for this hard decision region as transmitting of estimating;
Step 2: by formula (I
x-I
d)
2+ (Q
x-Q
d)
2calculating noise power P
n=(I
x-I
d)
2+ (Q
x-Q
d)
2;
Step 3: by the power P transmitted estimated described in formulae discovery
s;
Step 4: calculate
estimate the signal to noise ratio of decision statistics.
Step 5: establish modulation system to adopt QAM modulation, modulation system number is M, and signal to noise ratio is expressed as
Will
As signal-to-noise ratio (SNR) estimation value.
Threshold value set-up mode is as follows:
As SNR>=5log
2m-2, corresponding threshold value span is 0 < ε < 0.5;
As SNR < 5log
2m-2, corresponding threshold value span is 0.5≤ε < 1.
The invention has the beneficial effects as follows, the method is according to modulation system system number with by dividing threshold value the estimated value of signal to noise ratio, thus can realize reasonably dividing threshold value according to signal to noise ratio and modulation system, under achieving high s/n ratio condition, more decision statistics is adjudicated, under Low SNR, less decision statistics is adjudicated.
Accompanying drawing explanation
Fig. 1 is the part decision threshold method to set up flow chart of mimo wireless communication of the present invention based on signal-to-noise ratio (SNR) estimation;
Fig. 2 is 16QAM modulation constellation.
Embodiment
Below in conjunction with drawings and Examples, the present invention is further described.
Mimo wireless communication is based on the part decision threshold method to set up of signal-to-noise ratio (SNR) estimation, and the method comprises: estimate signal to noise ratio according to the coordinate of decision statistics and constellation coordinate; According to the signal to noise ratio estimated and modulation system number, the scope to threshold value is arranged.
Specifically comprise the following steps:
On planisphere, divide the hard decision region of decision statistics in advance, wherein unique corresponding one of each hard decision region transmits, and is called constellation point.Such as, Fig. 1 is the hard decision region according to 16QAM model split, and each hard decision region is with dotted line or reference axis for border, and the black circle in each hard decision region is constellation point corresponding to this hard decision region.Suppose that decision statistics constellation point in planisphere is mapped as y, coordinate is (I
x, Q
x), belonging to y, the constellation point coordinate in hard decision region is (I
d, Q
d).
As shown in Figure 2, receiving terminal estimates the signal to noise ratio of decision statistics y in accordance with the following steps:
Step one: determine the hard decision region belonging to decision statistics y, using constellation point D corresponding for this hard decision region as transmitting of estimating;
Step 2: by formula (I
x-I
d)
2+ (Q
x-Q
d)
2calculating noise power P
n=(I
x-I
d)
2+ (Q
x-Q
d)
2;
Step 3: by the power P transmitted estimated described in formulae discovery
s;
Step 4: calculate
estimate the signal to noise ratio of decision statistics.
Step 5: establish modulation system to adopt QAM modulation, modulation system number is M, and signal to noise ratio is expressed as
Threshold value set-up mode is as follows:
As SNR>=5log
2m-2, corresponding threshold value span is 0 < ε < 0.5;
As SNR < 5log
2m-2, corresponding threshold value span is 0.5≤ε < 1.
Embodiment 1: modulation system is 4QAM modulation, then ask for according to above-mentioned steps one to step 4
numerical value, will
as the estimated value of signal to noise ratio snr;
When SNR >=8, corresponding threshold value span is 0 < ε < 0.5;
As SNR < 8, corresponding threshold value span is 0.5≤ε < 1.
Embodiment 2: modulation system is 16QAM modulation, then ask for according to above-mentioned steps one to step 4
numerical value, as the estimated value of signal to noise ratio snr;
When SNR >=18, corresponding threshold value span is 0 < ε < 0.5;
As SNR < 18, corresponding threshold value span is 0.5≤ε < 1.
Embodiment 3: modulation system is 64QAM modulation, then ask for according to above-mentioned steps one to step 4
numerical value, as the estimated value of signal to noise ratio snr;
When SNR >=28, corresponding threshold value span is 0 < ε < 0.5;
As SNR < 28, corresponding threshold value span is 0.5≤ε < 1.
The invention has the beneficial effects as follows, the method is according to modulation system system number with by dividing threshold value the estimated value of signal to noise ratio, thus can realize reasonably dividing threshold value according to signal to noise ratio and modulation system, under achieving high s/n ratio condition, more decision statistics is adjudicated, under Low SNR, less decision statistics is adjudicated.
By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection scope of the present invention.