Embodiment
Embodiments of the invention provide a kind of acquisition methods of ultra-wideband channel model of discrete time, as shown in Figure 1, may further comprise the steps:
Step s101, the discrete time obtained in the signal bunch at interval and the discrete time in footpath at interval.
Step s102, according to bunch discrete time at interval and the discrete time in footpath at interval, the discrete time model of the amplitude of obtaining bunch and the amplitude in footpath.
Step s103, obtain shadow effect the shadow effect of the influence of amplitude is taken advantage of sex factor.
Step s104, according to bunch amplitude and the discrete time model of amplitude in footpath, and shadow effect is taken advantage of sex factor, the discrete time of obtaining bunch at interval in and the discrete time in footpath in blanking time, the stochastic variable of signal amplitude is as the ultra-wideband channel model of discrete time.
Among the step s101 in the said method, the discrete time of supposing bunch is Δ T not at interval, and the discrete time in footpath is spaced apart Δ t.The standard of the discrete time interval delta T of then obtaining in the signal bunch and the discrete time interval of delta t in footpath is: make the probability that arrives 1 bunch of signal in the time interval of Δ T be the specific factor of the probability that arrives 2 bunches of signals, make the probability that arrives 1 footpath signal in the time interval of the Δ t specific factor for the probability that arrives 2 footpath signals.Wherein, the probability P that arrives k time bunch of signal or footpath signal in blanking time in the t meets Poisson distribution, promptly
Wherein: λ is a distributed constant, and its value is obtained by existing continuous ultra-wideband channel model; N (s) is bunch signal of arrival in the time s or the number of times of footpath signal.
Among the step s102 in the said method, the amplitude of supposing m bunch is ξ [m], and the amplitude in n footpath is β [n].Then according to bunch the discrete time interval delta T and the discrete time interval of delta t in footpath, obtain m bunch amplitude ξ [m] and n amplitude ss [n] directly and be respectively:
Wherein: n
1, n
2Normal Distribution,
n
1~Normal(0,σ
1)?
n
2~Normal(0,σ
2)?
Γ wherein
m=Γ Δ T, γ
n=γ Δ t, σ
1, σ
2By providing in the existing continuous ultra-wideband channel model; Γ is a bunch delay parameter, and γ is the footpath delay parameter, by providing in the existing continuous ultra-wideband channel model.Ω
0Be a constant, can be assumed to be 1.
Among the step s103 in the said method, need to determine that shadow effect take advantage of sex factor to the shadow effect of the influence of amplitude, suppose that it is X that shadow effect is taken advantage of sex factor, then the normal distribution of X obedience index be 201g (X) ∝ Normal (0, σ
x), wherein: σ
xBy obtaining in the existing continuous ultra-wideband channel model.
Among the step s104 in the said method, the stochastic variable of supposing signal amplitude is U[m, n], then in m Δ T bunch interval and n Δ t directly in blanking time, the stochastic variable U[m of signal amplitude, n] computing formula be: U[m, n]=XPB ξ [m] β [n];
Wherein: X is that shadow effect is taken advantage of sex factor, and P is that two-value distributes, and equiprobablely gets 1 or-1, and expression is because the phasing back that reflection may cause.B is that also two-value distributes, and gets 1 or get 0.Be illustrated respectively in m bunch time, arrival or do not have arriving signal in n footpath time.According in the prior art to the algorithms of different of LOS (Line-Of-Sight, sighting distance) and NLOS (Non-Line-Of-Sight, non line of sight), the distribution of B also divides LOS and two kinds of situations of NLOS.
(1), LOS: work as m=0, during n=0, P (B=1)=1.Work as m〉0, during n=0, P (B=1)=Λ Δ t, P (B=0)=1-Λ Δ t.Work as m〉0, n〉0 o'clock
P(B=1)=λΛΔtΔT,P(B=0)=1-λΛΔtΔT。
(2), NLOS: when n=0, P (B=1)=Λ Δ t, P (B=0)=1-Λ Δ t.As n〉P (B=1)=λ Λ Δ t Δ T 0 time, P (B=0)=1-λ Λ Δ t Δ T.
Below in conjunction with existing UWB continuous channel model is that the present invention is further illustrated on the basis.
Provide a kind of channel model in the prior art, by (Λ, λ, Γ, γ, σ
1, σ
2, σ
x) 7 parameters describe fully, according to the different of dual-mode antenna spacing and whether exist LOS, this model provided four kinds of typical UWB applied environments (model parameter value under the CM1~CM4), as shown in table 1.Wherein the CM1 correspondence is the view distance environment of antenna distance 0-4m, and CM2 is the nlos environment apart from 0-4m, and CM3 is the nlos environment apart from 4-10m, and CM4 is that multipath delay is expanded very large nlos environment.
A kind of channel model parameter that provides in table 1 prior art
Parameter |
CM1 |
CM2 |
CM3 |
CM4 |
Λ(1/ns) |
0.0233 |
0.4 |
0.0677 |
0.0677 |
λ(1/ns) |
2.5 |
0.5 |
2.1 |
2.1 |
Γ (bunch delay parameter) |
7.1 |
5.5 |
14.00 |
24.00 |
γ (footpath delay parameter) |
4.3 |
6.7 |
7.9 |
12 |
σ
1(dB)
|
3.3941 |
3.3941 |
3.3941 |
3.3941 |
σ
2(dB)
|
3.3941 |
3.3941 |
3.3941 |
3.3941 |
σ
x(dB)
|
3 |
3 |
3 |
3 |
Based on the parameter of the above-mentioned UWB continuous channel model that provides, the acquisition methods of the ultra-wideband channel model of the discrete time that the embodiment of the invention proposes specifically may further comprise the steps as shown in Figure 2:
Step s201, definite bunch discrete time interval delta T and the discrete time interval of delta t in footpath;
In ultra-wideband communication system, signal has the feature that cluster arrives, and comprises a plurality of footpaths in each bunch again, bunch and all obey time of advent in footpath Poisson distribution, receive in the t that in blanking time k time bunch or probability directly also obey Poisson distribution, promptly
Wherein the value of λ is by providing in the existing continuous ultra-wideband channel model, and its concrete value is provided by form 1.
The standard of definite bunch the discrete time interval delta T and the discrete time interval of delta t in footpath is: make the probability that arrives 1 bunch of signal in the time interval of Δ T much larger than the probability that arrives 2 bunches of signals; Make the probability that in the time interval of Δ t, arrives 1 footpath signal much larger than the probability that arrives 2 footpath signals.Here with much larger than concrete standard to be 100 times be example, therefore can get:
With
Thereby the discrete time in discrete time interval delta T of obtaining bunch and footpath sees the following form 2 at interval:
Table 2: bunch the discrete time interval delta T and the discrete time in footpath at interval
|
CM1 |
CM2 |
CM3 |
CM4 |
ΔT(ns) |
0.858 |
0.05 |
0.295 |
0.295 |
Δt(ns) |
0.008 |
0.04 |
0.0095 |
0.0095 |
Step s202, according to bunch the discrete time interval delta T and the discrete time interval of delta t in footpath, obtain the discrete time model of m bunch amplitude ξ [m] and n amplitude ss [n] directly.
Amplitude ss [n] computing formula in m bunch amplitude ξ [m] and n footpath is:
Wherein: n
1, n
2Normal Distribution, n
1~Normal (0, σ
1)
n
2~Normal(0,σ
2)?
Γ
m=Γ/Δ T γ
n=γ/Δ t, σ
1, σ
2Provide by form 1.Γ is a bunch delay parameter, and γ is the footpath delay parameter, is provided by form 1.Ω
0Be a constant, can be assumed to be 1.
Step s203, determine that shadow effect takes advantage of sex factor X to the shadow effect of the influence of amplitude, X obey the index normal distribution be 201g (X) ∝ Normal (0, σ
x), wherein: σ
xProvide by table 1.
Step s204, obtain in m the Δ T bunch interval and n footpath in blanking time the stochastic variable U[m of signal amplitude, n], U[m, n] computing formula be: U[m, n]=XPB ξ [m] β [n];
Wherein: P is that two-value distributes, and equiprobablely gets 1 or-1, and expression is because the phasing back that reflection may cause.B is that also two-value distributes, and gets 1 or get 0.Be illustrated respectively in m bunch time, arrival or do not have arriving signal in n footpath time.According to the algorithms of different of in the prior art LOS and NLOS being taked, the distribution of B also divides LOS and two kinds of situations of NLOS.1, LOS: work as m=0, during n=0, P (B=1)=1.Work as m〉0, during n=0, P (B=1)=Λ Δ t, P (B=0)=1-Λ Δ t.Work as m〉0, n〉0 o'clock P (B=1)=λ Λ Δ t Δ T, P (B=0)=1-λ Λ Δ t Δ T.2, NLOS: when n=0, P (B=1)=Λ Δ t, P (B=0)=1-Λ Δ t.As n〉P (B=1)=λ Λ Δ t Δ T 0 time, P (B=0)=1-λ Λ Δ t Δ T.
Can adopt following steps as shown in Figure 3 during the model instance of the discrete time model in making up the embodiment of the invention:
Step s301, obtain one group of bunch of random sequence C[m],
For NLOS:
For LOS:
Step s302, to each C[i] determine one group of footpath sequence r[i, n].At C[i]=0 place, r[i, n]=0; C[i]=1 place, r[i then, n] be a random sequence.
r[i,n]=0?
?c[i]=0
Step s303, the two-dimensional random array r[m that obtains by s301, s302, n], to all r[i, j]=1 (i j), obtains its signal amplitude U[i, j]:
So far, just obtained an example of the ultra-wideband channel model of discrete time.
Embodiments of the invention also provide a kind of ultra-wideband channel model deriving means of discrete time, and its structure specifically comprises as shown in Figure 4:
Time interval acquiring unit 10, the discrete time that is used for obtaining signal bunch at interval and the discrete time in footpath at interval;
Amplitude acquiring unit 20, be used for according to time interval acquiring unit 10 obtain bunch discrete time at interval and the discrete time in footpath at interval, the discrete time model of the amplitude of obtaining bunch and the amplitude in footpath;
Take advantage of sex factor acquiring unit 30, be used to obtain shadow effect the shadow effect of the influence of described amplitude is taken advantage of sex factor;
Channel model acquiring unit 40, be used for according to amplitude acquiring unit 20 obtain bunch amplitude and the discrete time model of amplitude in footpath, and the shadow effect of taking advantage of sex factor acquiring unit 30 to obtain is taken advantage of sex factor, acquisition time interval acquiring unit 10 obtain bunch discrete time at interval in and the discrete time in footpath in blanking time, the stochastic variable of signal amplitude is as the ultra-wideband channel model of discrete time.
Concrete, time interval acquiring unit 10 further comprises:
Bunch discrete time interval acquiring subelement, the discrete time interval delta T that is used to obtain bunch, concrete: the discrete time interval delta T of obtaining bunch makes the probability that arrives 1 bunch of signal in time interval of the Δ T specific factor for the probability that arrives 2 bunches of signals;
Footpath discrete time interval acquiring subelement is used to obtain discrete time interval of delta t directly, and is concrete: obtain the discrete time interval of delta t in footpath, make that the interior probability that arrives 1 footpath signal of the time interval of Δ t is to arrive the directly specific factor of the probability of signals 2 times.
Concrete, amplitude acquiring unit 20 is specially first amplitude and obtains subelement, and the amplitude that is used for according to m bunch is ξ [m], and the amplitude in n footpath is β [n]; Concrete,
The discrete time model of the amplitude in described amplitude of obtaining bunch and footpath is specially:
Wherein: n
1, n
2Normal Distribution, n
1~Normal (0, σ
1)
n
2~Normal(0,σ
2)?
Γ
m=Γ Δ T γ
n=γ Δ t, σ
1, σ
2By obtaining in the continuous ultra-wideband channel model, Γ is a bunch delay parameter, and γ is the footpath delay parameter, Ω
0Be a constant, the discrete time that Δ T is bunch at interval, Δ t be the discrete time interval in footpath.
Concrete, channel model acquiring unit 40 is specially first channel model and obtains subelement, the discrete time that is used to obtain bunch at interval in and the discrete time in footpath in blanking time, the stochastic variable of signal amplitude is specially:
If in m the Δ T bunch interval and n Δ t directly in blanking time, the stochastic variable of signal amplitude is U[m, n], U[m then, n] be: U[m, n]=XPB ξ [m] β [n];
Wherein: P gets 1 or-1, and expression is because the phasing back that reflection may cause; B is for getting 1 or 0; Be illustrated respectively in m bunch time, arriving or do not have arriving signal, X in n footpath time is that shadow effect is taken advantage of sex factor, and ξ [m] is m bunch a amplitude, and β [n] is the amplitude in n footpath.
The method and apparatus that provides by the embodiment of the invention, directly utilize the discretization signal bunch and the obtaining of the ultra-wideband channel model of having realized discrete time the time of advent at interval in footpath, have and calculate simple, convenient and practical advantage, and can directly extrapolate the general formula of relevant channel characteristics according to embodiments of the invention, be convenient to emulation and calculating channel characteristic.
Through the above description of the embodiments, those skilled in the art can be well understood to the present invention and can realize by the mode that software adds essential general hardware platform, can certainly pass through hardware, but the former is better execution mode under a lot of situation.Based on such understanding, the part that technical scheme of the present invention contributes to prior art in essence in other words can embody with the form of software product, this computer software product is stored in the storage medium, comprises that some instructions are used so that an equipment is carried out the described method of each embodiment of the present invention.
More than disclosed only be several specific embodiment of the present invention, still, the present invention is not limited thereto, any those skilled in the art can think variation all should fall into protection scope of the present invention.