CN102769593A - Method and device for generation of downlink reference signals of communication system - Google Patents

Abstract

The invention provides a method for generation of downlink reference signals of a communication system. The method includes the steps: generating a pseudo random sequence c (n) with the length of MPN; generating reference signals according to the pseudo random sequence; determining an initial position vshift of each reference signal; mapping the first reference signal to a downlink resource unit corresponding to the veshift of a first downlink symbol; and mapping other reference signals to corresponding downlink resource units by means of sequential gradual increasing or decreasing of subcarrier indexes according to the sequence of OFDM (orthogonal frequency division multiplexing) symbols of the reference signals. The invention further provides a device for generation of downlink reference signals.

Description

A kind of generation method and device that is used for the communication system down link reference signal

Technical field

The present invention relates to OFDM (OFDM) access technology field, relate in particular to a kind of generation method and device that is used for the communication system down link reference signal.

Background technology

In the existing communication system that uses the OFDM access technology, reference signal (RS, Reference Signal) can be used for channel estimating, channel quality measurement, timing estimation etc.Reference signal is that the factors such as transmission means, multi-access mode, shared bandwidth and frequency spectrum resource according to system design.

The LTE system is a broadband system, and (RB) is unit with Resource Block, has designed length reference signal comparatively flexibly.In the LTE system, down link (DownLink) mainly contains two types of reference signals: cell special reference (Cell-specific RS) and UE DRS (Dedicated Reference Signal) (UE-specefic RS).Cell special reference is used for all users' in the sub-district coherent demodulation; The UE DRS (Dedicated Reference Signal) is that channel estimating in order to the Physical Downlink Shared Channel that carries out the specific user (PDSCH, Physical Downlink Shared Channel) is with demodulating data.

The power network communication system is a power load monitoring system, adopts the multichannel orthogonal frequency division multiplexi.The spectrum distribution of this system is discrete, is made up of 40 discontinuous subbands, and each subband bandwidth is 25kHz.Subcarrier spacing is 2kHz, and each OFDM symbol comprises 10 number of sub-carrier.The reference signal design scheme of existing multichannel ofdm system can not be used for such multichannel narrowband systems.Therefore, need to design the descending pilot frequency scheme again, make it can satisfy the demand of systematic function and identical networking to the such multichannel narrowband systems of power network communication system.

Summary of the invention

The invention provides a kind of generation method and device that is used for the communication system down link reference signal.

A kind of generation method that is used for the communication system down link reference signal that the embodiment of the invention proposes comprises the steps:

Generation length is M _PNPseudo random sequence c (n);

Produce reference signal according to said pseudo random sequence;

According to the current area sign, confirm reference signal original position v _Shift

First reference signal is mapped to the v of first descending symbol _ShiftOn the corresponding downlink resource unit; Order according to the OFDM symbol at reference signal place with the mode of sub-carrier indices increasing or decreasing successively, is mapped to all the other reference signals on the corresponding downstream Resource Unit.

Preferably, said generation length is M _PNPseudo random sequence c (n), it is 31 Gold sequence that pseudo random sequence is defined as length, its initial value does Be Cell Identity CI, l is the index of the OFDM symbol at downlink reference signal place.

Preferably, saidly produce reference signal according to said pseudo random sequence and comprise:

According to formula

generate reference signal r on l the OFDM symbol k number of sub-carrier (l, k).

Preferably, said according to the definite reference signal original position v of current area sign _ShiftComprise:

According to formula

Confirm reference signal original position v _Shiff, wherein

Be cell ID,

The number of sub carrier wave that comprises for subband.

The embodiment of the invention also proposes a kind of generating apparatus of downlink reference signal, comprising:

The pseudo random sequence module, being used to generate length is M _PNPseudo random sequence c (n);

The reference signal generation module is used for the pseudo random sequence that generated according to said pseudo random sequence module, produces reference signal;

The original position module is used for confirming reference signal original position v according to the current area sign _Shift

Mapping block is used for said first reference signal of reference signal generation module is mapped to the v of first descending symbol _ShiftOn the corresponding downlink resource unit; Order according to the OFDM symbol at reference signal place with the mode of sub-carrier indices increasing or decreasing successively, is mapped to all the other reference signals on the corresponding downstream Resource Unit.

Preferably, said generation length is M _PNPseudo random sequence c (n), it is 31 Gold sequence that pseudo random sequence is defined as length, its initial value does Be Cell Identity CI, l is the index of the OFDM symbol at downlink reference signal place.

Preferably, said reference signal generation module comprises:

The reference signal generation unit; Be used for according to formula

generate reference signal r on l the OFDM symbol k number of sub-carrier (l, k).

Preferably, said original position module is according to formula

Confirm reference signal original position v _Shift, wherein

Be cell ID,

The number of sub carrier wave that comprises for subband.

Can find out from above technical scheme, according to the downlink reference signal of the present invention program's generation.It is simple in structure, and the reference signal position is compact, can satisfy the system business demand, can make channel estimating simultaneously, Noise Variance Estimation, and the algorithm of the timing offset of frequency domain is realized simpler, systematic function is also brought guarantee.This scheme is specially adapted to the such multichannel narrow-band communication system of power network communication system.

Description of drawings

Fig. 1 a and Fig. 1 b are the sketch map of the downlink reference signal pattern of embodiment of the invention proposition;

Fig. 2 is the flow chart of the generation downlink reference signal of embodiment of the invention proposition.

Embodiment

The downlink reference signal pattern that the embodiment of the invention proposes is shown in Fig. 1 a and Fig. 1 b, and its empty grid is represented the downlink resource unit, and the shade grid is represented downlink reference signal.In the wireless frame structure of power network communication system; Preceding 13 OFDM symbols of each radio frames are used to send downlink information, in the scheme that the embodiment of the invention one proposes, a reference signal unit are arranged all on each OFDM symbol; And increase along with the index l of OFDM symbol; The index k of the subcarrier at reference signal unit place also increases progressively, and up to arriving the maximum subcarrier of call number, and then begins to increase progressively arrangement from the sub-carrier indices of minimum.

The reference signal position (Vshift) of first OFDM symbol is relevant with sub-district ID.Wherein, Fig. 1 a is depicted as the downlink reference signal pattern of sub-district a, and wherein the reference signal position Vshift of first OFDM symbol is 0, and Fig. 1 b is depicted as the downlink reference signal pattern of sub-district b, and wherein the reference signal position Vshift of first OFDM symbol is 3.If also there are other sub-districts, the reference signal position Vshift of its first OFDM symbol can also get other values.

Through this arrangement mode that increases progressively, and the Vshift of neighbor cell is different, the identical place, running time-frequency resource unit of neighbor cell, and reference signal staggers and reduces with disturbing frequently.Certainly, the arrangement of successively decreasing of the subcarrier at reference signal unit place also can reach same effect.

Fig. 2 shows the flow process of the generation downlink reference signal of embodiment of the invention proposition, comprises the steps:

Step 201: generating length is the pseudo random sequence of N_DLSymbol.N_DLSymbol representes the number of the OFDM symbol at downlink reference signal place in the radio frames.

The method that generates pseudo random sequence has a lot, and for example generating reference signal in the LTE system also is to rely on pseudo random sequence.Below provide a kind of concrete example that generates pseudo random sequence:

Pseudo random sequence employing length is 31 Gold sequence.Output length is M _PNRandom sequence c (n), its initial value does

Be cell ID, l is the index of the OFDM symbol at downlink reference signal place.

More than be merely the example that the present invention program is known more and lift, not in order to restriction the present invention.Any distortion that those skilled in the art do this example, be equal to replacement, all should be included within the protection range of the present invention.

Step 202:, produce N_DLSymbol reference signal according to said pseudo random sequence.

According to formula (1) generate reference signal r on l the OFDM symbol k number of sub-carrier (l, k):

$r(l,k)=\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(0\right))+\mathrm{<figure-callout\; id="1"\; label="j"\; filenames="HSA00000487886900011.png,HSA00000487886900012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{1}{\sqrt{2}}(1-2\&CenterDot;c\left(1\right))---\left(1\right)$

L represent descending OFDM notation index 0,1 ..., 8,9,10,11, N_DLSymbol-1}.N_DLSymbol is the descending reference symbol numbers, and k representes the sub-carrier indices of reference signal.

After generation finishes; L=l+1; The next r of

regeneration (l, k).

After traveling through the l on the radio frames, accomplish the generation of reference sequences.

Step 203:, confirm the original position v of reference signal in radio frames according to cell ID _Shift

The resource mapping and the v of descending reference sequence _ShiffRelevant, different v _ShiftThe pilot tone mapping position is also different, and this scheme can suppress interference among adjacent cells effectively.Fig. 1 has provided v respectively _ShiftEqual 0 with equal 3 reference signal mapping pattern.

$v_{\mathrm{shift}}=N_{\mathrm{ID}}^{\mathrm{cell}}\mathrm{mod}{N}_{\mathrm{sc}}^{\mathrm{RB}}---\left(2\right)$

Wherein,

representes sub-district ID; Son of

expression has 10 number of sub-carrier

V then _ShiftSpan be: 0,1,2 ... 9.

Step 204: first reference signal is mapped to v _ShiftCorresponding downlink resource unit; The mode that the subcarrier that belongs to according to reference signal increases progressively successively is mapped to all the other reference signals on the corresponding downstream Resource Unit.

The sub-carrier indices position of reference signal and the corresponding relation of OFDM notation index be suc as formula shown in (3),

$k=(l+v_{\mathrm{shift}})\mathrm{mod}{N}_{\mathrm{sc}}^{\mathrm{RB}}l=\mathrm{0,1},...,N\_\mathrm{DLSymbol}-1---\left(3\right)$

The embodiment of the invention also proposes a kind of generating apparatus of downlink reference signal, comprising:

The pseudo random sequence module, being used to generate length is M _PNPseudo random sequence c (n);

The reference signal generation module is used for the pseudo random sequence that generated according to said pseudo random sequence module, produces reference signal;

The original position module is used for confirming reference signal original position v according to the current area sign _Shift

Mapping block is used for said first reference signal of reference signal generation module is mapped to the v of first descending symbol _ShiftOn the corresponding downlink resource unit; Order according to the OFDM symbol at reference signal place with the mode of sub-carrier indices increasing or decreasing successively, is mapped to all the other reference signals on the corresponding downstream Resource Unit.

Preferably, said generation length is M _PNPseudo random sequence c (n), it is 31 Gold sequence that pseudo random sequence adopts length.Its initial value is

is that cell ID, l are the index of the OFDM symbol at downlink reference signal place.

Preferably, said reference signal generation module comprises:

The reference signal generation unit; Be used for according to formula generate reference signal r on l the OFDM symbol k number of sub-carrier (l, k).

Preferably, said original position module is according to formula

Confirm reference signal original position v _Shift, wherein Be cell ID,

The number of sub carrier wave that comprises for subband.

The present invention takes all factors into consideration the factors such as frame structure, spectrum distribution, subband bandwidth and identical networking of electric power pool, has designed the downlink reference signal that is applicable to this system.It is simple in structure, and the reference signal position is compact, can satisfy the system business demand, can make channel estimating simultaneously, Noise Variance Estimation, and the algorithm of the timing offset of frequency domain is realized simpler, systematic function is also brought guarantee.

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 (8)

1. a generation method that is used for the communication system down link reference signal is characterized in that, comprises the steps:

Generation length is M _PNPseudo random sequence c (n);

Produce reference signal according to said pseudo random sequence;

According to the current area sign, confirm reference signal original position v _Shift

First reference signal is mapped to the v of first descending symbol _ShiftOn the corresponding downlink resource unit; Order according to the OFDM symbol at reference signal place with the mode of sub-carrier indices increasing or decreasing successively, is mapped to all the other reference signals on the corresponding downstream Resource Unit.

2. method according to claim 1 is characterized in that, said generation length is M _PNPseudo random sequence c (n), it is 31 Gold sequence that pseudo random sequence is defined as length, its initial value does

Be Cell Identity CI, l is the index of the OFDM symbol at downlink reference signal place.

3. according to claim 1 and 2 described methods, it is characterized in that, saidly produce reference signal according to said pseudo random sequence and comprise:

Generate l OFDM symbol k according to formula

Reference signal r on the subcarrier (l, k).

4. method according to claim 1 is characterized in that, and is said according to the definite reference signal original position v of current area sign _ShiftComprise:

According to formula

Confirm reference signal original position v _Shift, wherein

Be cell ID,

The number of sub carrier wave that comprises for subband.

5. the generating apparatus of a downlink reference signal is characterized in that, comprising:

The pseudo random sequence module, being used to generate length is M _PNPseudo random sequence c (n);

The reference signal generation module is used for the pseudo random sequence that generated according to said pseudo random sequence module, produces reference signal;

The original position module is used for confirming reference signal original position v according to the current area sign _Shift

Mapping block is used for said first reference signal of reference signal generation module is mapped to the v of first descending symbol _ShiftOn the corresponding downlink resource unit; Order according to the OFDM symbol at reference signal place with the mode of sub-carrier indices increasing or decreasing successively, is mapped to all the other reference signals on the corresponding downstream Resource Unit.

6. device according to claim 5 is characterized in that, said generation length is M _PNPseudo random sequence c (n), it is 31 Gold sequence that pseudo random sequence is defined as length, its initial value does

Be Cell Identity CI, l is the index of the OFDM symbol at downlink reference signal place.

7. according to claim 5 and 6 described devices, it is characterized in that said reference signal generation module comprises:

The reference signal generation unit; Be used for according to formula

generate reference signal r on l the OFDM symbol k number of sub-carrier (l, k).

8. device according to claim 4 is characterized in that, said original position module is according to formula

Confirm reference signal original position v _Shift, wherein

Be cell ID,

The number of sub carrier wave that comprises for subband.

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