CN103841071A - Method for channel extermination in wireless communication system - Google Patents

Abstract

Disclosed is a method for channel extermination in a wireless communication system. The method comprises: according to a district ID and an OFDM (orthogonal frequency division multiplexing) symbol index, generating a long pilot frequency sequence for all pilot frequencies of each frequency point on an OFDM symbol time; according to the frequency point index of each frequency point, intercepting a short pilot frequency sequence corresponding to the frequency point from the long pilot frequency sequence, the length of the short pilot frequency sequence being decided by the number of pilot frequency sequences needed by ODFM symbols which bear the pilot frequencies on each frequency point in a pilot frequency pattern; and after resource mapping is performed on the short pilot frequency sequence, a receiving end carrying out the channel estimation. By applying the embodiments of the invention, different pilot frequency sequences can be generated for pilot frequency positions of multiple frequency points on the same OFDM time, the system peak-to-average ratio is reduced, and the channel estimation correctness is further improved.

Description

A kind of method of channel estimating in wireless communication system

Technical field

The application relates to communication technical field, more specifically, relates to the method for channel estimating in a kind of wireless communication system.

Background technology

Wireless communication system takies discontinuous spectral bandwidth, shown in accompanying drawing 1.Each frequency domain is that the physical channel of 25kHz bandwidth is defined as a frequency, at most

(

) individual frequency.Each frequency adopts OFDM (OFDM) technology, and all discontinuous frequencies condense together, and systematic unity dispatching distribution, to user, has formed the communication system with carrier aggregation characteristic.

This wireless communication system corresponding wireless frame length on each frequency is 25ms, comprises 45 OFDM symbols.Shown in accompanying drawing 2, downlink resource takies 13 OFDM symbols, and random access resource takies 4 OFDM symbols, and ascending resource takies 27 OFDM symbols.

Wireless communication system descending pilot frequency pattern, referring to accompanying drawing 3, has altogether

individual pilot frequency design.On each OFDM symbol of each frequency, have a resource element (RE) as pilot tone, the position (k, l) of this pilot tone is according to cell ID

l determines with OFDM symbolic number.

$k=(v_{\mathrm{shift}}+l)\mathrm{mod}{N}_{\mathrm{sc}}^{\mathrm{RB}};$

$l=\mathrm{0,1},{...N}_{\mathrm{sym}}^{\mathrm{DL}}-1.$

Wherein

carrier number in a subframe

downlink resource takies the number of OFDM symbol frequency number

community

In each pilot frequency locations, it is as follows that pilot frequency sequence generates formula:

Downlink reference signal adopts PN sequence, and the downlink reference signal that each frequency produces is:

$r_{l,k}\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1)),$ m=0

L: the OFDM notation index in a subframe

C (n) is pseudo random sequence, is generated by the Gold sequence of length 31.Output length is M _pNrandom sequence c (n) (n=0,1 ..., M _pN-1) generation formula is:

c(n)=(x ₁(n+N _C)+x ₂(n+N _C))mod2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2

Wherein N _c=1600, first m sequential register is initialized as x ₁(0)=1, x ₁(n)=0, n=1,2 ..., 30. second m sequential registers are initialized as

c _initinitial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}},$ $l=\mathrm{0,1},...N_{\mathrm{Sym}}^{\mathrm{DL}}-1.$

Because wireless communication system is in same OFDM symbol time,

the downlink reference signal that in individual frequency, each frequency produces is that pilot frequency sequence formula is identical.When

the time domain data of individual frequency is modulated to carrier frequency separately, signal when stack of multiple carrier frequency, if the phase place of multiple signals is consistent, the instantaneous power of the superposed signal obtaining will be far away higher than the average power of signal, can cause very high peak-to-average force ratio problem, further increase the error rate of channel estimating.

Summary of the invention

The embodiment of the present invention proposes the method for channel estimating in a kind of wireless communication system, can generate different pilot frequency sequences for the pilot frequency locations of multiple frequencies on the same OFDM time, reduces system peak-to-average ratio, further reduces the accuracy of channel estimating.

The technical scheme of the embodiment of the present invention is as follows:

A method for channel estimating in wireless communication system, described method comprises:

Be a long pilot frequency sequence of all pilot tones generations of the each frequency on OFDM symbol time according to community ID and orthogonal frequency division multiplex OFDM notation index;

Intercept at described long pilot frequency sequence the short pilots sequence that this frequency is corresponding according to the frequency index value of each frequency, the length of short pilots sequence depends on the number of the required pilot frequency sequence of OFDM symbol that carries pilot tone in pilot frequency design on each frequency;

Described short pilots sequence carries out being converted to time-domain signal after resource mapping, launch described time-domain signal by antenna port, the time-domain signal receiving is transformed into frequency domain by receiving terminal, and the frequency-region signal and short pilots sequence corresponding to this frequency that receive according to pilot frequency locations are carried out channel estimating.

Described all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence and comprise:

Long pilot frequency sequence by $r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$ Determine,

$l=\mathrm{0,1},...,N_{\mathrm{Sym}}^{\mathrm{DL}}-1;$

M span 0,1 ...,

frequency number

it is the number that downlink resource takies OFDM symbol;

Wherein C() be pseudo random sequence, by community l determines C(with OFDM notation index) initial value, initial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Described all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence and comprise:

Long pilot frequency sequence by $r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$ Determine,

l=v _shift,v _shift+4,v _shift+8； $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}4;$

M span 0,1 ...,

frequency number

Wherein C() be pseudo random sequence, by community

l determines C(with OFDM notation index) initial value, initial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Described all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence and comprise:

Long pilot frequency sequence by $r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$ Determine,

l=2,6,10；

M span 0,1 ...,

frequency number

Wherein C() be pseudo random sequence, by community

l determines C(with OFDM notation index) initial value, initial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Described short pilots sequence is carried out resource mapping and is comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is definite by k and l,

carrier number in a subframe $N_{\mathrm{sc}}^{\mathrm{RB}},$ $l=\mathrm{0,1},...,N_{\mathrm{Sym}}^{\mathrm{DL}}-1.$

Described short pilots sequence is carried out resource mapping and is comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is determined by k and l, k=2,7; l=v _shift, v _shift+ 4, v _shift+ 8,

Described short pilots sequence is carried out resource mapping and is comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is determined by k and l, k=v _shift+ 1, v _shift+ 5, l=2,6,10,

Described short pilots sequence is carried out resource mapping and is comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is determined by k and l, k=1, and 2 ..., 8, l=2,6,10.

From technique scheme, can find out, be a long pilot frequency sequence of all pilot tones generations of the each frequency on OFDM symbol time according to community ID and OFDM notation index in embodiments of the present invention; Then, then according to the frequency index value of each frequency intercept at described long pilot frequency sequence the short pilots sequence that this frequency is corresponding.Like this, for each frequency, its short pilots sequence is not identical, described short pilots sequence carries out being converted to time-domain signal after resource mapping, launch time-domain signal by antenna port, the time-domain signal receiving is transformed into frequency domain by receiving terminal, and the frequency-region signal and short pilots sequence corresponding to this frequency that receive according to pilot frequency locations are carried out channel estimating.Owing to can, for the pilot frequency locations of multiple frequencies on the same OFDM time generates different pilot frequency sequences, just reducing system peak-to-average ratio, further improve the accuracy of channel estimating.

Accompanying drawing explanation

Fig. 1 is wireless communication system spectrum diagram;

Fig. 2 is frequency time interval resource structural representation;

Fig. 3 is wireless communication system descending pilot frequency pattern 1;

Fig. 4 is the method flow schematic diagram of channel estimating in wireless communication system;

Fig. 5 is wireless communication system descending pilot frequency pattern 2;

Fig. 6 is wireless communication system descending pilot frequency pattern 3;

Fig. 7 is wireless communication system descending pilot frequency pattern 4.

Embodiment

For making the object, technical solutions and advantages of the present invention express clearlyer, below in conjunction with drawings and the specific embodiments, the present invention is further described in more detail.

In embodiments of the present invention, be a long pilot frequency sequence of all pilot tones generations of the each frequency on OFDM symbol time according to community ID and OFDM notation index; Then, then according to the frequency index value of each frequency intercept at described long pilot frequency sequence the short pilots sequence that this frequency is corresponding.Like this, for each frequency, its short pilots sequence is not identical, described short pilots sequence carries out being converted to time-domain signal after resource mapping, launch time-domain signal by antenna port, the time-domain signal receiving is transformed into frequency domain by receiving terminal, and the frequency-region signal and short pilots sequence corresponding to this frequency that receive according to pilot frequency locations are carried out channel estimating.

Owing to can, for the pilot frequency locations of multiple frequencies on the same OFDM time generates different pilot frequency sequences, entering and close behind road, system peak-to-average, than reducing, therefore compared with prior art adopts technical scheme of the present invention can submit the accuracy of channel estimating to.

Are method flow schematic diagrames of channel estimating in wireless communication system referring to accompanying drawing 4, specifically comprise the following steps:

Step 401, all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence.

First according to community

generate a long pilot frequency sequence with OFDM notation index (l) all pilot tones that to utilize following formula be the each frequency on OFDM symbol.

$r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1)),$ Wherein l is OFDM symbolic number, and the span of m need to be determined according to the number of pilot tone, c() be pseudo random sequence.

Due in the prior art, equal all the time 0 for different frequency m, in same OFDM symbol time, pilot frequency sequence corresponding to each frequency is identical.Therefore cause each frequency to be modulated to carrier frequency separately and will cause very high peak-to-average force ratio after closing road, further caused the high problem of channel estimation error rate.

In the present invention, the value of m has certain scope, within the scope of this, by different values, obtains long pilot frequency sequence.

Step 402, intercept at described long pilot frequency sequence the short pilots sequence that this frequency is corresponding according to the frequency index value of each frequency, the length of short pilots sequence depends on the number of the required pilot frequency sequence of OFDM symbol that carries pilot tone in pilot frequency design on each frequency;

Then, in the long pilot frequency sequence in step 401, intercept the short pilots sequence that this frequency is corresponding according to the frequency index value of each frequency.For example, long pilot frequency sequence is that { 0,1,2,3,4,5,6,7,8,9}, calculating short pilots sequence corresponding to intercepting according to frequency index value is the 4th sequence, intercepts short pilots sequence { 3} for this frequency.Wherein, { length of 3} depends on the number of the required pilot frequency sequence of OFDM symbol that carries pilot tone in pilot frequency design on each frequency to short pilots sequence.

Step 403, short pilots sequence carry out being converted to time-domain signal after resource mapping, launch time-domain signal by antenna port, the time-domain signal receiving is transformed into frequency domain by receiving terminal, and the frequency-region signal and short pilots sequence corresponding to this frequency that receive according to pilot frequency locations are carried out channel estimating.

Be n for index value _pRBfrequency, l pilot frequency sequence corresponding to OFDM symbol is mapped to symbol

upper, as the downlink reference signal in a radio frames.Receiving terminal is that downlink reference signal and short pilots sequence corresponding to this frequency are carried out channel estimating again according to the frequency-region signal after conversion.

Wherein, it is to adopt according to specific circumstances diverse ways that short pilots sequence is carried out resource mapping, and complex value modulation symbol correspondence position is determined by k and l, specifically referring to following embodiment.

Describe technical scheme of the present invention in detail below in conjunction with specific embodiment.

Embodiment mono-

Referring to accompanying drawing 3, in pilot frequency design 1, each frequency has 13 RE carrying pilot tones, is distributed on 13 OFDM symbols, has 1 RE carrying pilot tone, wherein on each OFDM symbol

$N_{\mathrm{Sym}}^{\mathrm{DL}}-1,$ $N_{\mathrm{Sym}}^{\mathrm{DL}}=13,$ $N_{\mathrm{sc}}^{\mathrm{RB}}=10.$

The downlink reference signal that each frequency, each radio frames produce is:

$r_l\left(n_{\mathrm{PRB}}\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left({2n}_{\mathrm{PRB}}\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c({2n}_{\mathrm{PRB}}+1))$

Wherein, n _pRBfor frequency index value, span 0,1 ...,

c (n) is pseudo random sequence, and the generating mode of c (n) is same as the prior art, is specially:

c(n)=(x ₁(n+N _C)+x ₂(n+N _C))mod2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2

Wherein N _c=1600, first m sequential register is initialized as x ₁(0)=1, x ₁(n)=0, n=1,2 ..., 30.Second m sequential register is initialized as

C _initinitial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Wherein

l represents an OFDM notation index in radio frames,

Reference signal sequence r _l(n _pRB), will be mapped in the following manner complex value modulation symbol

upper, the downlink reference signal as in a radio frames:

$a_{k,n_{\mathrm{PRB}},l}=r_l\left(n_{\mathrm{PRB}}\right).$

Embodiment bis-

For the descending pilot frequency pattern 2 shown in Fig. 5, each frequency has 6 RE carrying pilot tones, is distributed on 3 OFDM symbols, has 2 RE carrying pilot tones, position (k, l, the n of pilot tone on each OFDM symbol _pRB) according to cell ID

frequency index value n _pRBdetermine:

k=2，7；

l=v _shift,v _shift+4,v _shoft+8；

$n_{\mathrm{PRB}}=\mathrm{0,1},...,N_{\mathrm{RB}}^{\mathrm{DL}}-1$

Wherein $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}4,$ $N_{\mathrm{RB}}^{\mathrm{DL}}=480,$ $N_{\mathrm{ID}}^{\mathrm{cell}}=\mathrm{0,1},...,503.$

Whole downlink reference signals that each radio frames produces are:

$r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$

Wherein,

because each OFDM symbol in descending pilot frequency pattern 2 has 2 RE carrying pilot tones, and in embodiment mono-, each OFDM symbol has 1 RE carrying pilot tone.Therefore, the length difference of both short pilots sequences.

L=[v _shift4+v _shift8+v _shift],

c (n) is pseudo random sequence, and the generating mode of c (n) is:

c(n)=(x ₁(n+N _C)+x ₂(n+N _C))mod2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2

Wherein N _c=1600, first m sequential register is initialized as x ₁(0)=1, x ₁(n)=0, n=1,2 ..., 30. second m sequential registers are initialized as

C _initinitial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Wherein l=v _shiftv _shift+ 4, v _shift+ 8, represent an OFDM notation index in radio frames, frequency index value is n _pRBfrequency, l pilot frequency sequence corresponding to OFDM symbol is: $a_{k,n_{\mathrm{PRB}},l}=\left\{\begin{array}{cc}{r}_l\left({2n}_{\mathrm{PRB}}\right)& k=2\\ r_l(2n_{\mathrm{PRB}}+1)& k=7\end{array}\right..$

Embodiment tri-

For the descending pilot frequency pattern 3 shown in accompanying drawing 6, each frequency has 6 RE carrying pilot tones, is distributed on 3 OFDM symbols, has 2 RE carrying pilot tones, position (k, l, the n of pilot tone on each OFDM symbol _pRB) according to cell ID frequency index value n _pRBdetermine:

k=v _shift+1,v _shift+5；

l=2,6,10；

$n_{\mathrm{PRB}}=\mathrm{0,1},...,N_{\mathrm{RB}}^{\mathrm{DL}}-1;$

Wherein $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}4,$ $N_{\mathrm{RB}}^{\mathrm{DL}}=480,$ $N_{\mathrm{ID}}^{\mathrm{cell}}=\mathrm{0,1},...,503.$ Whole downlink reference signals that each radio frames produces are:

$r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$

Wherein,

l=2,6,10.C (n) is pseudo random sequence, and the generating mode of c (n) is:

c(n)=(x ₁(n+N _C)+x ₂(n+N _C))mod2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2

Wherein N _c=1600, first m sequential register is initialized as x ₁(0)=1, x ₁(n)=0, n=1,2 ..., 30. second m sequential registers are initialized as

C _initinitial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Wherein l=2,6,10, represent an OFDM notation index in radio frames,

Frequency index value is n _pRBfrequency, l pilot frequency sequence corresponding to OFDM symbol is: $a_{k,n_{\mathrm{PRB}},l}=\left\{\begin{array}{cc}{r}_l\left({2n}_{\mathrm{PRB}}\right)& k=v_{\mathrm{shift}}+1\\ r_l(2n_{\mathrm{PRB}}+1)& k=v_{\mathrm{shift}}+5\end{array}\right..$

Embodiment tetra-

For the descending pilot frequency pattern 4 shown in accompanying drawing 7, each frequency has 24 RE carrying pilot tones, is distributed on 3 OFDM symbols, has 8 RE carrying pilot tones on each OFDM symbol, and the pilot tone of 8 RE is to produce by 8 times of spread spectrums, position (k, l, the n of pilot tone _pRB) according to cell ID

frequency index value n _pRBdetermine:

k=1,2,...,8；

l=2,6,10；

$n_{\mathrm{PRB}}=\mathrm{0,1},...,N_{\mathrm{RB}}^{\mathrm{DL}}-1;$

Wherein $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}4,$ $N_{\mathrm{RB}}^{\mathrm{DL}}=480,$ $N_{\mathrm{ID}}^{\mathrm{cell}}=\mathrm{0,1},...,503.$

The downlink reference signal process that each radio frames produces is as follows:

$r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HDA00002445872100041.png,HDA00002445872100051.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$

Wherein,

l=2,6,10.C (n) is pseudo random sequence, and the generating mode of c (n) is:

c(n)=(x ₁(n+N _C)+x ₂(n+N _C))mod2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2

Wherein N _c=1600, first m sequential register is initialized as x ₁(0)=1, x ₁(n)=0, n=1,2 ..., 30. second m sequential registers are initialized as

C _initinitial value is $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

Wherein l=2,6,10, represent an OFDM notation index in radio frames.

Frequency index value is n _pRBfrequency, l pilot frequency sequence corresponding to OFDM symbol is: $a_{{k,n}_{\mathrm{PRB}},l}=r_l\left(n_{\mathrm{PRB}}\right)\&times;\mathrm{Os}(\mathrm{sf},k-1),$ Wherein k=1,2 ..., 8, $\mathrm{sf}=\mathrm{mod}(N_{\mathrm{ID}}^{\mathrm{cell}}+n_{\mathrm{PRB}},8),$ Which spreading code sf represents.

Os=[1,1,1,1,1,1,1,1;...

1,1,1,1,-1,-1,-1,-1;...

1,1,-1,-1,1,1,-1,-1;...

1,1,-1,-1,-1,-1,1,1;...

1,-1,1,-1,1,-1,1,-1;...

1,-1,1,-1,-1,1,-1,1;...

1,-1,-1,1,1,-1,-1,1;...

1,-1,-1,1,-1,1,1,-1]

The above, be only preferred embodiment of the present invention, is not intended to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (8)

1. a method for channel estimating in wireless communication system, is characterized in that, described method comprises:

Be a long pilot frequency sequence of all pilot tones generations of the each frequency on OFDM symbol time according to community ID and orthogonal frequency division multiplex OFDM notation index;

Intercept at described long pilot frequency sequence the short pilots sequence that this frequency is corresponding according to the frequency index value of each frequency, the length of short pilots sequence depends on the number of the required pilot frequency sequence of OFDM symbol that carries pilot tone in pilot frequency design on each frequency;

Described short pilots sequence carries out being converted to time-domain signal after resource mapping, launch described time-domain signal by antenna port, the time-domain signal receiving is transformed into frequency domain by receiving terminal, and the frequency-region signal and short pilots sequence corresponding to this frequency that receive according to pilot frequency locations are carried out channel estimating.

2. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence and comprise:

Long pilot frequency sequence by $r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+j\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$ Determine,

$l=\mathrm{0,1},...,N_{\mathrm{Sym}}^{\mathrm{DL}}-1;$

M span 0,1 ..., frequency number

it is the number that downlink resource takies OFDM symbol;

Wherein C() be pseudo random sequence, by community l determines C(with OFDM notation index) initial value, initial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

3. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence and comprise:

Long pilot frequency sequence by $r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+j\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$ Determine,

l=v _shift,v _shift+4,v _shift+8； $v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}4;$

M span 0,1 ...,

frequency number

Wherein C() be pseudo random sequence, by community

l determines C(with OFDM notation index) initial value, initial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

4. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described all pilot tones that are the each frequency on OFDM symbol time according to community ID and OFDM notation index generate a long pilot frequency sequence and comprise:

Long pilot frequency sequence by $r_l\left(m\right)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(2m\right))+j\frac{1}{\sqrt{2}}(1-2\&CenterDot;c(2m+1))$ Determine,

l=2,6,10；

M span 0,1 ...,

frequency number

Wherein C() be pseudo random sequence, by community

l determines C(with OFDM notation index) initial value, initial value is: $c_{\mathrm{init}}=2^{10}\&CenterDot;(l+1)\&CenterDot;(2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}+1)+2\&CenterDot;N_{\mathrm{ID}}^{\mathrm{cell}}.$

5. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described short pilots sequence is carried out resource mapping and comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is definite by k and l,

carrier number in a subframe $N_{\mathrm{sc}}^{\mathrm{RB}},$ $l=\mathrm{0,1},...{,N}_{\mathrm{Sym}}^{\mathrm{DL}}-1.$

6. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described short pilots sequence is carried out resource mapping and comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is determined by k and l, k=2,7; l=v _shift, v _shift+ 4, v _shift+ 8,

7. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described short pilots sequence is carried out resource mapping and comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is determined by k and l, k=v _shift+ 1, v _shift+ 5, l=2,6,10,

8. the method for channel estimating in wireless communication system according to claim 1, is characterized in that, described short pilots sequence is carried out resource mapping and comprised:

Described short pilots sequence mapping is put on corresponding complex value modulation symbol to described pilot tone, and described complex value modulation symbol correspondence position is determined by k and l, k=1, and 2 ..., 8, l=2,6,10.

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