CN101577691B - Pilot frequency distributing method and pilot frequency power optimizing method - Google Patents

Abstract

The invention discloses a pilot frequency distributing method which comprises: preprocessing and mapping the data of streams in a transmitter by carrier waves; transmitting the data preprocessed and mapped by the carrier waves to a fast Fourier transform inversion module; preprocessing and mapping the pilot frequency of the streams in the transmitter by the carrier waves; and transmitting the pilot frequency preprocessed and mapped by the carrier waves to the fast Fourier transform inversion module. In the carrier wave mapping processing, when the number of the streams is four, the pilot frequency is positioned in the second symbol, the third symbol, the fourth symbol or the fifth symbol of a resource block. According to the technical scheme, under the condition of a fading channel, the channel estimated accuracy and the system performance can be increased by reasonably using a power resource.

Description

Pilot distribution method and pilot frequency power optimizing method

Technical field

The present invention relates to the communications field, and especially, relate to pilot distribution method and pilot frequency power optimizing method.

Background technology

OFDM (Orthogonal Frequency Division Multiplexing; Abbreviate OFDM as) be a kind of multi-carrier transmission pattern; Convert the low-speed parallel data flow transmitted into through the data flow with high-speed transfer, the system that makes reduces the susceptibility of the frequency selective fading of channel.OFDM (Orthogonal Frequency Division MultipleAccess; Abbreviating OFDMA as) technology is present and one of the major programme of following wireless communication technology; This scheme is that different users distributes some different subcarriers, and these subcarriers allow overlapping at frequency domain but remain mutually orthogonal.

Micro-wave access to global intercommunication (Worldwide Interoperability for MicrowaveAccess abbreviates WiMAX as) system is based on the system of broadband wireless communication of OFDMA technology.But; Develop rapidly along with the communication technology; Mobile WiMAX system based on Institute of Electrical and Electronics Engineers (Institute for Electrical and Electronic Engineers abbreviates IEEE as) 802.16e air interface standard can not satisfy the demand of following people to high transfer rate, high-throughput, high-speed mobile and the low time delay of wide-band mobile communication.

At present, the TGm task groups of IEEE802.16 working group is being devoted to formulate evolved air interface specification 802.16m, and this standard can be supported higher peak rate, higher spectrum efficiency and sector capacity.

In wireless communication system, be the technology that can further strengthen data transmission performance based on the channel estimation technique of pilot tone.But under the situation of the total transmit power limited of system, if use the channel estimating based on pilot tone, then the increase of pilot power or reduction all can influence channel estimating to some extent.

On the one hand, the power that increases pilot tone can be suppressed noise and interference, has improved channel estimated accuracy, and still, pilot also can increase according to the interference of symbol, makes a concrete analysis of as follows:

In ofdm system, suppose that the subcarrier number is N, Cyclic Prefix (CyclicPrefix abbreviates CP as) length is Lcp time-domain sampling point, and the maximum delay spread of supposing channel is L, and L≤Lcp, and the time domain transmission signal x (n) that does not then add CP is:

$x\left(n\right)=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{X}_k\exp \left(j\frac{2\mathrm{\πkn}}{N}\right),0\≤n\≤N-1---\left(1\right)$

Wherein, be X _kBe the transmission data on k the carrier wave in time n place.

$r\left(n\right)=x\left(n\right)\⊗h_l\left(n\right)+w\left(n\right)$

$=\underset{l=0}{\overset{L-1}{\mathrm{\Σ}}}x{(n-l)}_N{h}_l\left(n\right)+w\left(n\right)$

$=\frac{1}{\sqrt{N}}\underset{l=0}{\overset{L-1}{\mathrm{\Σ}}}{h}_l\left(n\right)\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{X}_k\exp \left(j\frac{2\mathrm{\πk}(n-l)}{N}\right)+w\left(n\right)$

$=\frac{1}{\sqrt{N}}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}\left[X_k\exp \left(j\frac{2\mathrm{\πkn}}{N}\right)\underset{l=0}{\overset{L-1}{\mathrm{\Σ}}}{h}_l\left(n\right)\exp (-j\frac{2\mathrm{\πkl}}{N})\right]$

$=\frac{1}{N}\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}{X}_k{H}_k\left(n\right)\exp \left(j\frac{2\mathrm{\πkn}}{N}\right)+w\left(n\right)---\left(2\right)$

Wherein, h _lThe channel that becomes when (n) representing, n is an output time, 1 is the time delay in the every footpath of channel.

() N representes modulo-N arithmetic.H _k(n)=DFT _l{ h _l(n) } for the time frequency response that becomes, w (n) is the AWGN noise, and signal r (n) is done N point fast Fourier conversion (The Fast FourierTransform abbreviates FFT as), can obtain the restituted signal R on the time n k of the place number of sub-carrier _kFor:

$R_k=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}r\left(n\right)\exp (-j\frac{2\mathrm{\πkn}}{N})$

$=\frac{1}{N}\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}\left[\underset{m=0}{\overset{N-1}{\mathrm{\Σ}}}{X}_m{H}_m\left(n\right)\exp \left(j\frac{2\mathrm{\πmn}}{N}\right)\right]\exp (-j\frac{2\mathrm{\πkn}}{N})+v_k$

$=\frac{1}{N}\underset{m=0}{\overset{N-1}{\mathrm{\Σ}}}{X}_m\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{H}_m\left(n\right)\exp (-j\frac{2\mathrm{\π}(k-m)n}{N})+v_k$

$=\frac{1}{N}[X_k\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{H}_k\left(n\right)+\underset{\underset{m\≠k}{m=0}}{\overset{N-1}{\mathrm{\Σ}}}{X}_m\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{H}_m\left(n\right)\exp (-j\frac{2\mathrm{\π}(k-m)n}{N})]+v_k$

$=\frac{1}{N}[X_k\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{H}_k\left(n\right)+I\left(k\right)]+v_k---\left(3\right)$

V wherein _kFor { w (n) } does k value behind the FFT, inter-carrier interference is:

$I\left(k\right)=\underset{\underset{m\≠k}{m=0}}{\overset{N-1}{\mathrm{\Σ}}}{X}_m\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{H}_m\left(n\right)\exp (-j\frac{2\mathrm{\π}(k-m)n}{N})---\left(4\right)$

By formula (2), definition H _m(n) be h _l(n) frequency response is:

$H_m\left(n\right)=\frac{1}{\sqrt{N}}\underset{l=0}{\overset{L-1}{\mathrm{\Σ}}}{h}_l\left(n\right)\exp (-j\frac{2\mathrm{\πml}}{N})---\left(5\right)$

Wherein, 0≤n≤N-1,0≤l≤G.

And along with the increase of frequency pilot sign power, the power of giving data symbol will inevitably reduce, and causes the decline of the signal to noise ratio of separating timing.

But from another point of view, the power that reduces frequency pilot sign can reduce channel estimated accuracy.

Therefore, under certain conditions, frequency pilot sign power should have the value of an optimization to exist with the ratio of data symbol power.Simultaneously, because wireless channel exists frequency selective fading and time selective fading, so the density of pilot tone and pilot tone arrangement mode also have very big influence to the performance of system.At present, also there is not well to optimize the scheme of pilot frequency distribution.

Summary of the invention

Considering at present also not have well to optimize the problem of pilot frequency distribution scheme and makes the present invention, and main purpose of the present invention for this reason is to provide a kind of pilot distribution method, with the problems referred to above in the solution correlation technique.

According to an aspect of the present invention, a kind of pilot distribution method is provided, has been applied to comprise the communication system of at least one transmitter, wherein, transmitter has four transmitting antennas at least.

Pilot distribution method according to the embodiment of the invention comprises: the data of each stream in the transmitter are carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and the carrier wave mapped data sends to the invert fast fourier transformation module; The pilot tone of each stream in the transmitter is carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and send to the invert fast fourier transformation module, wherein with the pilot tone that carrier wave shines upon; In the carrier wave mapping treatment; Be under four the situation, to make pilot tone be in the 2nd, 3,4,5 symbol of Resource Block, wherein at stream; The time domain of Resource Block has 6 OFDM symbols, and frequency domain has 18 number of sub-carrier.

Preferably, at the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, and distribute the 4th, 11,18 number of sub-carrier to give stream 2; At the 3rd symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, distribute the 7th, 17 number of sub-carrier to give stream 4; At the 4th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, distribute the 7th, 17 number of sub-carrier to give stream 3; At the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1.

Preferably, at the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, and distribute the 4th, 11,18 number of sub-carrier to give stream 2; At the 3rd symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, distribute the 7th, 17 number of sub-carrier to give stream 3; At the 4th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, distribute the 7th, 17 number of sub-carrier to give stream 4; At the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1.

In addition, further comprise in the above-mentioned processing: pilot sub-carrier number and data subcarrier number based on the symbol in the Resource Block carry out the pilot power setting.

Wherein, the operation of carrying out the pilot power setting is specially: confirm pilot sub-carrier power and data subcarrier power according to following formula, $\left\{\begin{array}{c}a\·P_P+b\·P_D\≤N_{\mathrm{FS}}\\ P_P/P_D=R,R\≥1\end{array}\right.;$ Wherein, a is the pilot sub-carrier number in the given symbol; B is the data subcarrier number in the given symbol; P _DBe data subcarrier power, P _PBe pilot sub-carrier power; N _FSSubcarrier in frequency domain number for Resource Block; Based on pilot sub-carrier power and data subcarrier power and the predefined average signal-to-noise ratio confirmed, confirm pilot sub-carrier noise data subcarrier signal to noise ratio when; Confirm the optimal pilot data subcarrier power ratio under the predetermined condition through link level simulation; Select the minimum pilot data sub-carrier power of the error rate or Block Error Rate to liken to and be the gain of the pilot tone under the predetermined condition.

Preferably, predetermined condition comprises: average signal-to-noise ratio, modulation coding mode, channel type.

According to the embodiment of the invention on the other hand, a kind of pilot distribution method is provided, has been applied to comprise the communication system of at least one transmitter, wherein, transmitter has four transmitting antennas at least.

Pilot distribution method according to the embodiment of the invention comprises: the data of each stream in the transmitter are carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and the carrier wave mapped data sends to the invert fast fourier transformation module; The pilot tone of each stream in the transmitter is carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and send to the invert fast fourier transformation module, wherein with the pilot tone that carrier wave shines upon; In the carrier wave mapping treatment; Be under four the situation, to make pilot tone be in the 1st, 2,5,6 symbol of Resource Block, wherein at stream; The time domain of Resource Block has 6 OFDM symbols, and frequency domain has 18 number of sub-carrier.

Preferably, at the 1st symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, and distribute the 7th, 17 number of sub-carrier to give stream 4; At the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, distribute the 4th, 11,18 number of sub-carrier to give stream 2; At the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1; At the 6th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, distribute the 7th, 17 number of sub-carrier to give stream 3.

Preferably, at the 1st symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, and distribute the 7th, 17 number of sub-carrier to give stream 3; At the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, distribute the 4th, 11,18 number of sub-carrier to give stream 2; At the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1; At the 6th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, distribute the 7th, 17 number of sub-carrier to give stream 4.

In addition, above-mentioned processing method further comprises: pilot sub-carrier number and data subcarrier number according to the symbol in the Resource Block carry out the pilot power setting.

Wherein, the operation of carrying out the pilot power setting is specially: confirm pilot sub-carrier power and data subcarrier power according to following formula, $\left\{\begin{array}{c}a\·P_P+b\·P_D\≤N_{\mathrm{FS}}\\ P_P/P_D=R,R\≥1\end{array}\right.;$ Wherein, a is the pilot sub-carrier number in the given symbol; B is the data subcarrier number in the given symbol; P _DBe data subcarrier power, P _PBe pilot sub-carrier power; N _FSSubcarrier in frequency domain number for Resource Block; Based on pilot sub-carrier power and data subcarrier power and the predefined average signal-to-noise ratio confirmed, confirm pilot sub-carrier noise data subcarrier signal to noise ratio when; Confirm the optimal pilot data subcarrier power ratio under the predetermined condition through link level simulation; Select the minimum pilot data sub-carrier power of the error rate or Block Error Rate to liken to and be the gain of the pilot tone under the predetermined condition.

Preferably, above-mentioned predetermined condition comprises: average signal-to-noise ratio, modulation coding mode, channel type.

Through technique scheme, can under the fading channel condition,, improve the performance of channel estimated accuracy and system through the reasonable use power resource.

Other features and advantages of the present invention will be set forth in specification subsequently, and, partly from specification, become apparent, perhaps understand by embodiment of the present invention.The object of the invention can be realized through the structure that in the specification of being write, claims and accompanying drawing, is particularly pointed out and obtained with other advantages.

Description of drawings

Accompanying drawing is used to provide further understanding of the present invention, and constitutes the part of specification, is used to explain the present invention with embodiments of the invention, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the flow chart according to the pilot distribution method of the inventive method embodiment 1;

Fig. 2 is the sketch map according to the simplification OFDM transmitter of the inventive method embodiment;

Fig. 3 is the sketch map according to the descending pilot frequency pattern of instance 1 among the inventive method embodiment 1;

Fig. 4 is the sketch map according to the descending pilot frequency pattern of instance 2 among the inventive method embodiment 1;

Fig. 5 is the pilot distribution method flow chart according to the inventive method embodiment 2;

Fig. 6 is the sketch map according to the descending pilot frequency pattern of instance 3 among the inventive method embodiment 2;

Fig. 7 is the sketch map according to the descending pilot frequency pattern of instance 4 among the inventive method embodiment 2;

Fig. 8 is the flow chart according to the pilot frequency power optimizing method of the inventive method embodiment 3; And

Fig. 9 is the flow chart of the instance 5 of method shown in Figure 8.

Embodiment

Below in conjunction with accompanying drawing the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein only is used for explanation and explains the present invention, and be not used in qualification the present invention.

Method embodiment 1

In the present embodiment, a kind of pilot distribution method is provided, has been applied to comprise the communication system of at least one transmitter, wherein, transmitter has four transmitting antennas at least, and wherein the time domain of Resource Block has 6 OFDM symbols, and frequency domain has 18 number of sub-carrier.Fig. 1 is the flow chart according to the pilot distribution method of the inventive method embodiment 1.

As shown in Figure 1, said method comprises:

Step S102 carries out the mapping of preliminary treatment (coding, modulation, many antenna processing) and carrier wave to the data of each stream in the transmitter, and will pass through preliminary treatment and the carrier wave mapped data sends to the invert fast fourier transformation module; This process can be understood with reference to the transmitter processes sketch map that Fig. 2 provides;

Step S104; The pilot tone of each stream in the transmitter is carried out preliminary treatment and carrier wave mapping; And the pilot tone that will pass through the mapping of preliminary treatment and carrier wave sends to IFFT (invert fast fourier transformation) module, wherein, and in the carrier wave mapping treatment; Be under four the situation, to make pilot tone be in the 2nd, 3,4,5 symbol of Resource Block at stream.

Instance 1: pilot frequency mode one

As shown in Figure 3, wherein colourless grid is represented data subcarrier, and the oblique line grid is represented pilot sub-carrier.The pilot tone of stream 1,2,3,4 is respectively with P1, P2, P3, P4 sign.Through giving the mode of the carrier wave in each flow distribution Resource Block, dispose the frequency pilot sign of confirming according to the number of stream.

Be that pilot tone is in the 2nd, 3,4 and 5 symbol of Resource Block under four the situation at stream, the 1st and the 6th symbol do not have frequency pilot sign, four streams be numbered stream 1, stream 2, stream 3 and stream 4, the distribution of above-mentioned frequency pilot sign is following:

(1) at the 2nd symbol of Resource Block; Distribute the 1st, 8,15 number of sub-carrier to give stream 1; Stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data, and distributes the 4th, 11,18 number of sub-carrier to give stream 2, and stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data;

(2) at the 3rd symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data; Distribute the 7th, 17 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data;

(3) at the 4th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data; Distribute the 7th, 17 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data;

(4) at the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data; 4,11,18 number of sub-carrier are given stream 1 distributively, and stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data.

Instance 2: pilot frequency mode two

As shown in Figure 4, wherein, colourless grid is represented data subcarrier, and the oblique line grid is represented pilot sub-carrier.The pilot tone of stream 1,2,3,4 is respectively with P1, P2, P3, P4 sign.Through giving the mode of the carrier wave in each flow distribution Resource Block, dispose pilot frequency distribution each symbol in the cycle of confirming according to the number of stream.

Be that pilot tone is in the 2nd, 3,4 and 5 symbol of Resource Block under four the situation at stream, the 1st and the 6th symbol do not have frequency pilot sign, four streams be numbered stream 1, stream 2, stream 3 and stream 4.The distribution of above-mentioned frequency pilot sign is following:

(1) at the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data; And distributing the 4th, 11,18 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data;

(2) at the 3rd symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data; Distribute the 7th, 17 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data;

(3) at the 4th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data; Distribute the 7th, 17 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data;

(4) at the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data; 4,11,18 number of sub-carrier are given stream 1 distributively, and stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data.

Method embodiment 2

In the present embodiment, a kind of pilot distribution method is provided, has been applied to comprise the communication system of at least one transmitter, wherein, transmitter has four transmitting antennas at least.Fig. 5 is the pilot distribution method flow chart according to the inventive method embodiment 2.

As shown in Figure 5, said method comprises:

Step S502 carries out the mapping of preliminary treatment (coding, modulation, many antenna processing) and carrier wave to the data of each stream in the transmitter, and will pass through preliminary treatment and the carrier wave mapped data sends to fast IFFT module;

Step S504; The pilot tone of each stream in the transmitter is carried out preliminary treatment and carrier wave mapping; And the pilot tone that will pass through the mapping of preliminary treatment and carrier wave sends to the IFFT module, wherein, and in the carrier wave mapping treatment; Be under four the situation, to make pilot tone be in the 1st, 2,5,6 symbol of Resource Block at stream.

Instance 3: pilot frequency mode three

As shown in Figure 6, wherein, colourless grid is represented data subcarrier, and the oblique line grid is represented pilot sub-carrier.The pilot tone of stream 1,2,3,4 is respectively with P1, P2, P3, P4 sign.Through giving the mode of the carrier wave in each flow distribution Resource Block, dispose pilot frequency distribution each symbol in the cycle of confirming according to the number of stream.

Be that pilot tone is in the 1st, 2,5 and 6 symbol of Resource Block under four the situation at stream, the 3rd and the 4th symbol do not have frequency pilot sign.Four streams be numbered stream 1, stream 2, stream 3 with stream 4, the distribution of described frequency pilot sign is following:

(1) at the 1st symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data; And distributing the 7th, 17 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data;

(2) at the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data; Distribute the 4th, 11,18 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data;

(3) at the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data; Distribute the 4th, 11,18 number of sub-carrier to give stream 1, stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data;

(4) at the 6th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data; Distribute the 7th, 17 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data.

Instance 4: pilot frequency mode four

As shown in Figure 7, wherein, blank grid is represented data subcarrier, and the oblique line grid is represented pilot sub-carrier.The pilot tone of stream 1,2,3,4 is respectively with P1, P2, P3, P4 sign.Through giving the mode of the carrier wave in each flow distribution Resource Block, dispose pilot frequency distribution each symbol in the cycle of confirming according to the number of stream.

Be that pilot tone is in the 1st, 2,5 and 6 symbol of Resource Block under four the situation at stream, the 3rd and the 4th symbol do not have frequency pilot sign, four streams be numbered stream 1, stream 2, stream 3 and stream 4.The distribution of frequency pilot sign is following:

(1) at the 1st symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data; And distributing the 7th, 17 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data;

(2) at the 2nd symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data; Distribute the 4th, 11,18 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data;

(3) at the 5th symbol of Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, stream 1,3,4 does not allow on this 3 number of sub-carrier, to send data; Distribute the 4th, 11,18 number of sub-carrier to give stream 1, stream 2,3,4 does not allow on this 3 number of sub-carrier, to send data;

(4) at the 6th symbol of Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, stream 1,2,4 does not allow on this 2 number of sub-carrier, to send data; Distribute the 7th, 17 number of sub-carrier to give stream 4, stream 1,2,3 does not allow on this 2 number of sub-carrier, to send data.

Method embodiment 3

According to the embodiment of the invention, a kind of pilot frequency power optimizing method is provided,

Fig. 8 is the flow chart according to the pilot frequency power optimizing method of the embodiment of the invention, and is as shown in Figure 8, comprises following processing:

Step S802 for different pilot frequency modes, confirms pilot sub-carrier power and data subcarrier power according to following formula, $\left\{\begin{array}{cc}a\·P_P+b\·P_D\≤N_{\mathrm{FS}}& \\ P_P/P_D=R,R\≥1& \end{array}\right.;$ Wherein, a is the pilot sub-carrier number in the given symbol; B is the data subcarrier number in the given symbol; P _DBe data subcarrier power, P _PBe pilot sub-carrier power; N _FSSubcarrier in frequency domain number for Resource Block (RB); N _TSTime domain symbolic number for Resource Block;

Step S804 based on pilot sub-carrier power and data subcarrier power and the predefined average signal-to-noise ratio confirmed, confirms pilot sub-carrier noise data subcarrier signal to noise ratio when;

Step S806 confirms the optimal pilot data subcarrier power ratio under the predetermined condition through link level simulation; The predetermined condition here comprises average signal-to-noise ratio, modulation coding mode, channel type etc.;

Step S808 selects the minimum pilot data sub-carrier power of the error rate (BER) or Block Error Rate (BLER) to liken to and is the gain of the pilot tone under the predetermined condition.

Through above processing, can optimize pilot power.

Suppose that the average power of each subcarrier is 1, then for a Physical Resource Block, maximum power is N _FSThe power of supposing frequency pilot sign is P _P, the power of data symbol is P _D, defining the two power ratio is P _P/ P _D=R, general R>=1.Suppose that average signal-to-noise ratio is ASNR (dB), this average signal-to-noise ratio is that corresponding data symbol power is 1.Supposing has a pilot sub-carrier in certain symbol of PRB, and b data subcarrier then has aP _P+ bP _D≤N _FSObviously, in order effectively to utilize power resource, P _P, P _DShould get the maximum of formula above satisfying.So actual data signal to noise ratio is P _D10 ^ASNR/10, actual pilot tone signal to noise ratio is P _P10 ^ASNR/10

Need to prove; The pilot frequency power optimizing method that the embodiment of the invention provides can use separately; The pilot distribution method that also can combine to provide in the preceding text uses together; That is, pilot sub-carrier number and the data subcarrier number according to the symbol in the Resource Block under the various pilot frequency modes carries out the pilot frequency power optimizing setting.

Instance 5

Below, be elaborated in conjunction with the pilot frequency power optimizing of accompanying drawing to pilot frequency mode one.Wherein, second and third, the pilot frequency power optimizing of four kinds of pilot frequency modes and first kind be similar, repeat no more once more.

For first kind of pilot frequency mode, as shown in Figure 3, comprise 18 number of sub-carrier, 6 OFDM symbols.Clearly can find out from pilot frequency mode, can support 4 streams (stream), the pilot tone of various flows is respectively with P1, P2, P3 and P4 sign.Therefore wherein flow 1,2 and respectively comprise 6 pilot tones, respectively comprise 4 pilot tones and flow 3,4, in a Resource Block, number that altogether can bearing modulation symbols is 18 * 6=108, wherein comprises pilot-frequency expense 2 * (6+4)=20 (for four streams).

As shown in Figure 9, the process of pilot frequency power optimizing is following in first kind of pilot frequency mode:

Step 902 can be known 18P by the configuration of the 1st, 6 symbol subcarrier in the Resource Block _D≤18.Configuration by the 2nd, 5 symbol subcarrier among the RB can be known 12P _D+ 3P _P≤18.Configuration by the 3rd, 4 symbol subcarrier among the RB can be known 14P _D+ 2P _P≤18.Consider P _P/ P _D=R, R>=1, and effectively utilize power, then P _D=18/ (12+3R), P _P=18R/ (12+3R).

Step 904 supposes that average signal-to-noise ratio is ASNR, and then the data signal to noise ratio is 18/ (12+3R) 10 ^ASNR/10, the pilot tone signal to noise ratio is 18R/ (12+3R) 10 ^ASNR/10, the noise power on the single sub-carrier is 1/10 ^ASNR/10

Step 906, given ASNR, modulation coding mode and channel type are carried out the best pilot data sub-carrier power ratio of link level simulation.

Step 908 selects the minimum pilot data power ratio of BER or BLER as the gain of the pilot tone under the specified conditions (boostting).

In sum, the method for a kind of ofdm communication system pilot frequency distribution and pilot frequency power optimizing is proposed by means of the present invention, can be under the fading channel condition; Through the reasonable use power resource; Improve channel estimated accuracy, effectively utilize power resource, improve the performance of system.

The above is merely the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (12)

1. pilot distribution method is applied to comprise the communication system of at least one transmitter, and wherein, said transmitter has four transmitting antennas at least, it is characterized in that, said method comprises:

The data of each stream in the transmitter are carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and the carrier wave mapped data sends to the invert fast fourier transformation module;

The pilot tone of each stream in the said transmitter is carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and send to the invert fast fourier transformation module, wherein with the pilot tone that carrier wave shines upon; In said carrier wave mapping treatment; Be under four the situation, to make pilot tone be in the 2nd, 3,4,5 symbol of Resource Block, wherein at stream; The time domain of said Resource Block has 6 OFDM symbols, and frequency domain has 18 number of sub-carrier.

2. method according to claim 1 is characterized in that,

At the 2nd symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, and distribute the 4th, 11,18 number of sub-carrier to give stream 2;

At the 3rd symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, distribute the 7th, 17 number of sub-carrier to give stream 4;

At the 4th symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, distribute the 7th, 17 number of sub-carrier to give stream 3;

At the 5th symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1.

3. method according to claim 1 is characterized in that,

At the 2nd symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, and distribute the 4th, 11,18 number of sub-carrier to give stream 2;

At the 3rd symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, distribute the 7th, 17 number of sub-carrier to give stream 3;

At the 4th symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, distribute the 7th, 17 number of sub-carrier to give stream 4;

At the 5th symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1.

4. according to each described method in the claim 1 to 3, it is characterized in that, further comprise:

Pilot sub-carrier number and data subcarrier number based on the symbol in the said Resource Block carry out the pilot power setting.

5. method according to claim 4 is characterized in that, the operation of carrying out the pilot power setting is specially:

Confirm pilot sub-carrier power and data subcarrier power according to following formula, $\left\{\begin{array}{c}a\·P_P+b\·P_D\≤N_{\mathrm{FS}}\\ P_P/P_D=R,R\≥1\end{array}\right.;$ Wherein, a is the pilot sub-carrier number in the given symbol; B is the data subcarrier number in the said given symbol; P _DBe data subcarrier power, P _PBe pilot sub-carrier power; N _FSSubcarrier in frequency domain number for said Resource Block;

Based on said pilot sub-carrier power and said data subcarrier power and the predefined average signal-to-noise ratio confirmed, confirm pilot sub-carrier noise data subcarrier signal to noise ratio when;

Confirm the optimal pilot data subcarrier power ratio under the predetermined condition through link level simulation;

Select the minimum pilot data sub-carrier power of the error rate or Block Error Rate to liken to and be the gain of the pilot tone under the said predetermined condition.

6. method according to claim 5 is characterized in that, said predetermined condition comprises: said average signal-to-noise ratio, modulation coding mode, channel type.

7. pilot distribution method is applied to comprise the communication system of at least one transmitter, and wherein, said transmitter has four transmitting antennas at least, it is characterized in that, said method comprises:

The data of each stream in the transmitter are carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and the carrier wave mapped data sends to the invert fast fourier transformation module;

The pilot tone of each stream in the said transmitter is carried out the mapping of preliminary treatment and carrier wave, and will pass through preliminary treatment and send to the invert fast fourier transformation module, wherein with the pilot tone that carrier wave shines upon; In said carrier wave mapping treatment; Be under four the situation, to make pilot tone be in the 1st, 2,5,6 symbol of Resource Block, wherein at stream; The time domain of said Resource Block has 6 OFDM symbols, and frequency domain has 18 number of sub-carrier.

8. method according to claim 7 is characterized in that,

At the 1st symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, and distribute the 7th, 17 number of sub-carrier to give stream 4;

At the 2nd symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, distribute the 4th, 11,18 number of sub-carrier to give stream 2;

At the 5th symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1;

At the 6th symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, distribute the 7th, 17 number of sub-carrier to give stream 3.

9. method according to claim 7 is characterized in that,

At the 1st symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 4, and distribute the 7th, 17 number of sub-carrier to give stream 3;

At the 2nd symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 1, distribute the 4th, 11,18 number of sub-carrier to give stream 2;

At the 5th symbol of said Resource Block, distribute the 1st, 8,15 number of sub-carrier to give stream 2, distribute the 4th, 11,18 number of sub-carrier to give stream 1;

At the 6th symbol of said Resource Block, distribute the 2nd, 12 number of sub-carrier to give stream 3, distribute the 7th, 17 number of sub-carrier to give stream 4.

10. according to each described method in the claim 7 to 9, it is characterized in that, further comprise:

Pilot sub-carrier number and data subcarrier number based on the symbol in the said Resource Block carry out the pilot power setting.

11. method according to claim 10 is characterized in that, the operation of carrying out the pilot power setting is specially:

Confirm pilot sub-carrier power and data subcarrier power according to following formula, $\left\{\begin{array}{c}a\·P_P+b\·P_D\≤N_{\mathrm{FS}}\\ P_P/P_D=R,R\≥1\end{array}\right.;$ Wherein, a is the pilot sub-carrier number in the given symbol in the said Resource Block; B is the data subcarrier number in the said given symbol; P _DBe data subcarrier power, P _PBe pilot sub-carrier power; N _FSSubcarrier in frequency domain number for said Resource Block;

Based on said pilot sub-carrier power and said data subcarrier power and the predefined average signal-to-noise ratio confirmed, confirm pilot sub-carrier noise data subcarrier signal to noise ratio when;

Confirm the optimal pilot data subcarrier power ratio under the predetermined condition through link level simulation;

Select the minimum pilot data sub-carrier power of the error rate or Block Error Rate to liken to and be the gain of the pilot tone under the said predetermined condition.

12. method according to claim 11 is characterized in that, said predetermined condition comprises: said average signal-to-noise ratio, modulation coding mode, channel type.

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