CN102457450A - TD-SCDMA channel estimation post-processing method and device - Google Patents

Abstract

The invention discloses a TD-SCDMA channel estimation post-processing method, which preprocesses the channel estimation result and selects the received signal power greater than the threshold P_thThe power of the received signal is less than the threshold P_thFiltering the path of (1), wherein Z is less than the maximum path number; superposing the sub-frame channel results output by the Z paths selected by preprocessing to obtain the superposed output value of the current sub-frame channel results; and obtaining a final current subframe channel estimation post-processing result according to the superposed output value of the current subframe channel result. The invention also discloses a device for processing the TD-SCDMA channel estimation. The TD-SCDMA channel estimation post-processing method and the device can reduce the noise component in the estimated channel and improve the channel estimation precision.

Description

TD-SCDMA channel estimating post-processing approach and device

Technical field

The present invention relates to wireless communication technology, particularly a kind of TD-SCDMA channel estimating post-processing approach and device.

Background technology

In wireless mobile communications, most of receiving algorithm need obtain wireless mobile channel model to carry out channel equalization and multi-user's demodulation.Generally, wireless mobile channel is a time varying channel, and in the low spreading rate TDD mode of 3G (Third Generation) Moblie affiliate tissue (3GPP) definition, wireless mobile channel can be considered time varying frequency selectivity multipath channel.In this mode of operation, adopt short burst to communicate, in a pulse period, wireless mobile channel can be adopted training sequence to realize channel estimating by the approximate LTI channel of regarding as.In this pattern, adopted the pattern of inserting training sequence (Midamble) at the burst middle part, this pattern is convenient to receiver and is obtained channel model, to realize channel equalization, multi-user's demodulation scheduling algorithm.

Owing to have noise jamming at receiving terminal; Therefore in the channel that estimates more noise component(s) is arranged; These noise component(s)s can cause the path signal of the vacation after the channel estimating, use these channel estimation results that comprise false routing information can make receptivity that very big decline is arranged.With joint detection receiver among the TD-SCDMA is example, and these noise component(s)s not only can cause user data to contain a large amount of noises, also can cause the operand of implementation algorithm to increase.

Summary of the invention

The technical problem that the present invention will solve is the noise component(s) that reduces in the channel that estimates, and improves channel estimated accuracy.

For solving the problems of the technologies described above, the present invention provides a kind of TD-SCDMA channel estimating post-processing approach, may further comprise the steps:

One. the result of channel estimating is carried out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering, Z is less than the maximum path number;

Two. will superpose through the subframe channel result of the selected Z paths output of preliminary treatment, obtain the output valve of current subframe channel result stack, the computing that specifically superposes is:

$H_{\mathrm{pre}-\mathrm{add}}\left(n\right)=\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{H}_{\mathrm{pre}}(n-m)$

$=[h_{\mathrm{Pre}-\mathrm{add}0}\left(n\right),h_{\mathrm{Pre}-\mathrm{add}1}\left(n\right),L,h_{\mathrm{Pre}-\mathrm{add}(W-1)}\left(n\right)],$

H _Pre(n)＝[h _Pre0(n)，h _Pre1(n)，L，H _Pre(W-1)(n)]；

Wherein, H _Pre-add(n) be that n is current subframe sequence number, h through the output valve of the n subframe channel result stack of the selected Z paths output of preliminary treatment _Pre-addk(n) be k the value of putting in the output valve of n subframe channel result stack, H _Pre(n) be channel result, h through the n subframe of the selected Z paths output of preliminary treatment _Prek(n) be the value of k point in the channel result of the n subframe that the selected Z paths of preliminary treatment is exported, n-m is the subframe sequence number of sliding stack, and M is total sequence length of sliding stack;

Three. according to the output valve of current subframe channel result stack, obtain the result of final current subframe channel estimating reprocessing;

The output valve H that the n subframe channel result who exports through the selected Z paths of preliminary treatment superposes _Pre-add(n) in, h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if greater than 0 _k(n) equal h _Pre-addk(n), h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if smaller or equal to 0 _k(n) equal 0, obtain the result of final n sub-frame channel estimating reprocessing, the result of promptly final current subframe channel estimating reprocessing;

H (n)=[h ₀(n), h ₁(n), L, h _(W-1)(n)], wherein, H (n) is the actual digital channel impulse response window of n subframe; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _k(n) be k sampled point among the actual digital channel impulse response window H (n) of n subframe, 0≤k≤W-1.

Thresholding P _ThCan be a ratio value of the maximum path power of the received signal power in the estimated channel impulse response.

For solving the problems of the technologies described above, the present invention also provides a kind of TD-SCDMA channel estimating after-treatment device, and this device comprises the channel multi-path pretreatment module, accumulator module, multipath are selected module as a result;

Said channel multi-path pretreatment module is used for the result of channel estimating is carried out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering, Z is less than the maximum path number;

Said accumulator module as a result is used for the subframe channel result through the selected Z paths output of said channel multi-path pretreatment module preliminary treatment is superposeed, and obtains the output valve of current subframe channel result stack, and the computing that specifically superposes is:

$H_{\mathrm{pre}-\mathrm{add}}\left(n\right)=\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{H}_{\mathrm{pre}}(n-m)$

$=[h_{\mathrm{Pre}-\mathrm{add}0}\left(n\right),h_{\mathrm{Pre}-\mathrm{add}1}\left(n\right),L,h_{\mathrm{Pre}-\mathrm{add}(W-1)}\left(n\right)],$

H _Pre(n)＝[h _Pre0(n)，h _Pre1(n)，L，h _Pre(W-1)(n)]；

Wherein, H _Pre-add(n) be that n is current subframe sequence number, h through the output valve of the n subframe channel result stack of the selected Z paths output of preliminary treatment _Pre-addk(n) be k the value of putting in the output valve of n subframe channel result stack, H _Pre(n) be channel result, h through the n subframe of the selected Z paths output of preliminary treatment _Prek(n) be the value of k point in the channel result of the n subframe that the selected Z paths of preliminary treatment is exported, n-m is the subframe sequence number of sliding stack, and M is total sequence length of sliding stack;

Said multipath is selected module, is used for the output valve according to the current subframe channel result stack of said accumulator module as a result, obtains the result of final current subframe channel estimating reprocessing;

The output valve H that the n subframe channel result who exports through the selected Z paths of preliminary treatment superposes _Pre-add(n) in, h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if greater than 0 _k(n) equal h _Pre-addk(n), h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if smaller or equal to 0 _k(n) equal 0, obtain the result of final n sub-frame channel estimating reprocessing, the result of promptly final current subframe channel estimating reprocessing;

H (n)=[h ₀(n), h ₁(n), L, h _(W-1)(n)], wherein, H (n) is the actual digital channel impulse response window of n subframe; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _k(n) be k sampled point among the actual digital channel impulse response window H (n) of n subframe, 0≤k≤W-1.

TD-SCDMA channel estimating post-processing approach of the present invention and device; Can reduce the noise component(s) in the channel that estimates; The user data noise content is low, and the operand of implementation algorithm reduces, and has improved channel estimated accuracy and has improved the performance of receiver in the TD-SCDMA system greatly.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done further explain.

Fig. 1 is a simple mobile radio system model;

Fig. 2 is TD-SCDMA channel estimating post-processing approach one an execution mode sketch map of the present invention;

Fig. 3 is TD-SCDMA channel estimating after-treatment device one an execution mode sketch map of the present invention.

Embodiment

In most mobile communcations system, Base-Band Processing is generally digital processing.Because a large amount of uses of pulse-shaping filter in mobile communcations system, the sample rate of baseband signal is generally spreading rate, is called one times of speed sampling.In analyzing below, the signal of being built in the mobile radio system model is the digital signal that a multiplying power is sampled.

The actual digital channel impulse response window of definition is:

H＝[h ₀，h ₁，L，h _W-1](1)

In the formula (1): H is a complex channel impulse response window; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _kBe the value of k sampled point in the complex channel impulse response window, 0≤k≤W-1.

Fig. 1 is a simple mobile radio system model.

When channel estimation method was linear algorithm or approximately linear algorithm, estimative figure channel impulse response window can be expressed as:

(2)

In the formula (2): W is that the window of channel impulse response window is long;

complex channel impulse response window for estimating;

is the value of k sampled point in the complex channel impulse response window of estimating; N is an additive noise.

In Fig. 1; Signal is propagated in wireless channel; Wireless channel is a multipath channel, and receiving signal is to obtain through delaying different a plurality of paths, and the received signal power on each path is inequality; In common wireless channel, preceding four to six paths that received signal power is bigger have comprised most of energy of arriving signal.When channel circumstance is comparatively good, the last most of energy that has just comprised arriving signal to three paths that received signal power is bigger.That is to say that the concentration of energy of multipath wireless channel is on limited several paths.On the other hand, the distribution of the noise energy on each path is just comparatively average.

TD-SCDMA channel estimating post-processing approach one execution mode of the present invention, as shown in Figure 2, may further comprise the steps:

One. the result of channel estimating is carried out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering, Z is less than the maximum path number;

According to the characteristics that channel energy distributes in the estimated channel impulse response, the Z paths that selected received signal power is bigger (Z is less than the maximum path number).Need set a thresholding when selecting the path; The setting of thresholding can have several different methods; Such as setting according to the percentage of the received signal power in the maximum path of received signal power; Teach good, thresholding can confirm as the maximum path of received signal power received signal power 1%, so just can tentatively filter and lose the false path that some clearly are noises.

Be specially:

(1) in the estimated channel impulse response, the path that the selective reception signal power is maximum, this path power is designated as maximum signal power P _Max

(2) calculate maximum signal power P _MaxA ratio value as thresholding, for example can confirm maximum signal power P _Max1% as thresholding P _Th

(3) result to channel estimating carries out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering;

Two. will superpose through the subframe channel result of the selected Z paths output of preliminary treatment, can adopt the form of moving average window that subframe channel result is advanced stack, obtain the output valve of current subframe channel result stack, the computing that specifically superposes is:

$H_{\mathrm{pre}-\mathrm{add}}\left(n\right)=\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{H}_{\mathrm{pre}}(n-m)$

$=[h_{\mathrm{Pre}-\mathrm{add}0}\left(n\right),h_{\mathrm{Pre}-\mathrm{add}1}\left(n\right),L,h_{\mathrm{Pre}-\mathrm{add}(W-1)}\left(n\right)]---\left(3\right),$

H _Pre(n)＝[h _Pre0(n)，h _Pre1(n)，L，h _Pre(W-1)(n)](4)，

Wherein, H _Pre-add(n) be that n is current subframe sequence number, h through the output valve of the n subframe channel result stack of the selected Z paths output of preliminary treatment _Pre-addk(n) be k the value of putting in the output valve of n subframe channel result stack, H _Pre(n) be channel result, h through the n subframe of the selected Z paths output of preliminary treatment _Prek(n) be the value of k point in the channel result of the n subframe that the selected Z paths of preliminary treatment is exported, n-m is the subframe sequence number of sliding stack, and M is total sequence length of sliding stack;

Three. according to the output valve that current subframe channel result superposes, obtain the result of final current subframe channel estimating reprocessing;

The output valve H that the n subframe channel result who exports through the selected Z paths of preliminary treatment superposes _Pre-add(n) in, h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if greater than 0 _k(n) equal h _Pre-addk(n), h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if smaller or equal to 0 _k(n) equal 0, obtain the result of final n sub-frame channel estimating reprocessing, the result of promptly final current subframe channel estimating reprocessing;

H(n)＝[h ₀(n)，h ₁(n)，L，h _(W-1)(n)](5)，

Wherein, H (n) is the actual digital channel impulse response window of n subframe; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _k(n) be k sampled point among the actual digital channel impulse response window H (n) of n subframe, 0≤k≤W-1.

TD-SCDMA channel estimating after-treatment device one execution mode of the present invention, as shown in Figure 3, comprise the channel multi-path pretreatment module, accumulator module, multipath are selected module as a result;

Said channel multi-path pretreatment module is used for the result of channel estimating is carried out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering, Z is less than the maximum path number; Thresholding P _ThBe a ratio value of the maximum path power of the received signal power in the estimated channel impulse response, preferable, ratio value is 1%;

Said accumulator module as a result is used for the subframe channel result through the selected Z paths output of said channel multi-path pretreatment module preliminary treatment is superposeed, and obtains the output valve of current subframe channel result stack, and the computing that specifically superposes is:

$H_{\mathrm{pre}-\mathrm{add}}\left(n\right)=\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{H}_{\mathrm{pre}}(n-m)$

$=[h_{\mathrm{Pre}-\mathrm{add}0}\left(n\right),h_{\mathrm{Pre}-\mathrm{add}1}\left(n\right),L,h_{\mathrm{Pre}-\mathrm{add}(W-1)}\left(n\right)],$

H _Pre(n)＝[h _Pre0(n)，h _Pre1(n)，L，h _Pre(W-1)(n)]；

Wherein, H _Pre-add(n) be that n is current subframe sequence number, h through the output valve of the n subframe channel result stack of the selected Z paths output of preliminary treatment _Pre-addk(n) be k the value of putting in the output valve of n subframe channel result stack, H _Pre(n) be channel result, h through the n subframe of the selected Z paths output of preliminary treatment _Prek(n) be the value of k point in the channel result of the n subframe that the selected Z paths of preliminary treatment is exported, n-m is the subframe sequence number of sliding stack, and M is total sequence length of sliding stack;

Said multipath is selected module, is used for the output valve according to the current subframe channel result stack of said accumulator module as a result, obtains the result of final current subframe channel estimating reprocessing;

The output valve H that the n subframe channel result who exports through the selected Z paths of preliminary treatment superposes _Pre-add(n) in, h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if greater than 0 _k(n) equal h _Pre-addk(n), h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if smaller or equal to 0 _k(n) equal 0, obtain the result of final n sub-frame channel estimating reprocessing, the result of promptly final current subframe channel estimating reprocessing;

H (n)=[h ₀(n), h ₁(n), L, h _(W-1)(n)], wherein, H (n) is the actual digital channel impulse response window of n subframe; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _k(n) be k sampled point among the actual digital channel impulse response window H (n) of n subframe, 0≤k≤W-1.

TD-SCDMA channel estimating post-processing approach of the present invention and device; Can reduce the noise component(s) in the channel that estimates; The user data noise content is low, and the operand of implementation algorithm reduces, and has improved channel estimated accuracy and has improved the performance of receiver in the TD-SCDMA system greatly.

The above is merely preferred embodiment of the present invention, and is in order to restriction the present invention, not all within spirit of the present invention and principle, any modification of being made, is equal to replacement, improvement etc., all should be included within the scope that the present invention protects.

Claims (6)

1. a TD-SCDMA channel estimating post-processing approach is characterized in that, may further comprise the steps:

One. the result of channel estimating is carried out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering, Z is less than the maximum path number;

Two. will superpose through the subframe channel result of the selected Z paths output of preliminary treatment, obtain the output valve of current subframe channel result stack, the computing that specifically superposes is:

$H_{\mathrm{pre}-\mathrm{add}}\left(n\right)=\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{H}_{\mathrm{pre}}(n-m)$

$=[h_{\mathrm{Pre}-\mathrm{add}0}\left(n\right),h_{\mathrm{Pre}-\mathrm{add}1}\left(n\right),L,h_{\mathrm{Pre}-\mathrm{add}(W-1)}\left(n\right)],$

H _Pre(n)＝[h _Pre0(n)，h _Pre1(n)，L，h _Pre(W-1)(n)]；

Wherein, H _Pre-add(n) be that n is current subframe sequence number, h through the output valve of the n subframe channel result stack of the selected Z paths output of preliminary treatment _Pre-addk(n) be k the value of putting in the output valve of n subframe channel result stack, H _Pre(n) be channel result, h through the n subframe of the selected Z paths output of preliminary treatment _Prek(n) be the value of k point in the channel result of the n subframe that the selected Z paths of preliminary treatment is exported, n-m is the subframe sequence number of sliding stack, and M is total sequence length of sliding stack;

Three. according to the output valve of current subframe channel result stack, obtain the result of final current subframe channel estimating reprocessing;

The output valve H that the n subframe channel result who exports through the selected Z paths of preliminary treatment superposes _Pre-add(n) in, h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if greater than 0 _k(n) equal h _Pre-addk(n), h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if smaller or equal to 0 _k(n) equal 0, obtain the result of final n sub-frame channel estimating reprocessing, the result of promptly final current subframe channel estimating reprocessing;

H (n)=[h ₀(n), h ₁(n), L, h _(W-1)(n)], wherein, H (n) is the actual digital channel impulse response window of n subframe; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _k(n) be k sampled point among the actual digital channel impulse response window H (n) of n subframe, 0≤k≤W-1.

2. TD-SCDMA channel estimating post-processing approach according to claim 1 is characterized in that thresholding P _ThA ratio value for the maximum path power of the received signal power in the estimated channel impulse response.

3. TD-SCDMA channel estimating post-processing approach according to claim 2 is characterized in that thresholding P _ThBe 1% of the received signal power in the maximum path of the received signal power in the estimated channel impulse response.

4. a TD-SCDMA channel estimating after-treatment device is characterized in that, comprises the channel multi-path pretreatment module, accumulator module, multipath are selected module as a result;

Said channel multi-path pretreatment module is used for the result of channel estimating is carried out preliminary treatment, and selected received signal power is greater than thresholding P _ThThe Z paths, with received signal power less than thresholding P _ThThe path filtering, Z is less than the maximum path number;

Said accumulator module as a result is used for the subframe channel result through the selected Z paths output of said channel multi-path pretreatment module preliminary treatment is superposeed, and obtains the output valve of current subframe channel result stack, and the computing that specifically superposes is:

$H_{\mathrm{pre}-\mathrm{add}}\left(n\right)=\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{H}_{\mathrm{pre}}(n-m)$

$=[h_{\mathrm{Pre}-\mathrm{add}0}\left(n\right),h_{\mathrm{Pre}-\mathrm{add}1}\left(n\right),L,h_{\mathrm{Pre}-\mathrm{add}(W-1)}\left(n\right)],$

H _Pre(n)＝[h _Pre0(n)，h _Pre1(n)，L，h _Pre(W-1)(n)]；

Wherein, H _Pre-add(n) be that n is current subframe sequence number, h through the output valve of the n subframe channel result stack of the selected Z paths output of preliminary treatment _Pre-addk(n) be k the value of putting in the output valve of n subframe channel result stack, H _Pre(n) be channel result, h through the n subframe of the selected Z paths output of preliminary treatment _Prek(n) be the value of k point in the channel result of the n subframe that the selected Z paths of preliminary treatment is exported, n-m is the subframe sequence number of sliding stack, and M is total sequence length of sliding stack;

Said multipath is selected module, is used for the output valve according to the current subframe channel result stack of said accumulator module as a result, obtains the result of final current subframe channel estimating reprocessing;

The output valve H that the n subframe channel result who exports through the selected Z paths of preliminary treatment superposes _Pre-add(n) in, h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if greater than 0 _k(n) equal h _Pre-addk(n), h _Pre-addk(n), then make k sampled point h among the actual digital channel impulse response window H (n) of n subframe if smaller or equal to 0 _k(n) equal 0, obtain the result of final n sub-frame channel estimating reprocessing, the result of promptly final current subframe channel estimating reprocessing;

H (n)=[h ₀(n), h ₁(n), L, h _(W-1)(n)], wherein, H (n) is the actual digital channel impulse response window of n subframe; W is that the window of complex channel impulse response window is long, i.e. the sampled point number; h _k(n) be k sampled point among the actual digital channel impulse response window H (n) of n subframe, 0≤k≤W-1.

5. TD-SCDMA channel estimating after-treatment device according to claim 4 is characterized in that thresholding P _ThA ratio value for the maximum path power of the received signal power in the estimated channel impulse response.

6. TD-SCDMA channel estimating post-processing approach according to claim 5 is characterized in that thresholding P _ThBe 1% of the received signal power in the maximum path of the received signal power in the estimated channel impulse response.

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