Background technology
High-order multi-antenna technology is one of key technology of senior Long Term Evolution (LTE-A or LTE-Advanced, Long Term Evolution Advanced) system, in order to improve system transfer rate.In order to realize the channel quality measurement after introducing high-order multi-antenna technology and data demodulates, LTE-Advanced system respectively defines two class frequency pilot signs: data demodulates pilot tone (DMRS, Demodulation Reference Signal) and channel quality measurement pilot tone (CSI-RS, Channel State Information-Reference Signal), wherein, demodulation pilot frequency is used for the reference symbol of Physical Downlink Shared Channel (PDSCH, Physical Downlink SharedChannel) demodulation.The reference symbol that measurement pilot frequency is measured for CSI (channel stateinformation) indicates (CQI for channel quality, ChannelQuality Indicator), pre-coding matrix instruction (PMI, Precoding MatrixIndicator), the reporting of stratum's instruction information such as (RI, Rank Indicator).The structure of two class reference symbols may be used for supporting as multipoint cooperative (CoMP, CoordinatedMulti-Point), the new technical feature of the LTE-A such as spatial reuse.
In LTE, what adopt is that CRS carries out pilot measurement, namely all users use common pilot to carry out channel estimating, this public reference signal needs emitting side additional notifications receiving terminal to have employed which kind of pretreatment mode to the data of launching, expense is comparatively large simultaneously, in addition in MU-MIMO, because multiple UE is using identical CRS, the orthogonal of pilot tone cannot be realized, be therefore unable to estimate interference.
In LTE-A, in order to reduce the expense of pilot tone, witness mark symbol and demodulation reference mark are separately designed, JieDuHuaYu II Decoction reference signal and the identical pretreatment mode of data acquisition, demodulation data reference symbol is according to the available order information MAP reference symbol of dispatched users respective channels simultaneously, therefore can be adaptive according to order information adjustment expense, like this in the situation that order is lower, greatly expense can be reduced.Current LTE-A comprises the consistent viewpoint that demodulation reference mark design is formed: terminal is distinctive, the identical precoding processing of data acquisition of demodulation reference mark as corresponding in: particular terminal and dispatched users.On the resource that only to exist only in network side (as eNodeB) is dispatched by transfer of data and layer.At network side, the reference symbol that different layers transmits is mutually orthogonal.The design criterion of demodulation reference mark is to the expansion of the specific reference symbol of the terminal for beamforming transmission defined in R8 to multilayer.
In the related, have passed at present under normal cyclic prefix and normal sub-frames situation, to the baseline of the demodulation pilot frequency mapping method of the dual-layer beamforming (double-deck beamforming) of R9, as shown in Figure 1.But in lte-a system, the design problem of demodulating data reference mark sequence is not also discussed.
In LTE, the pseudo random sequence that URS (user-specific reference signal) sequence adopts is 31 long golden sequences.Be M for length
pNsequence c (n) (n=0,1 ..., M
pN-1), producing method is:
c(n)=(x
1(n+N
C)+x
2(n+N
C))mod 2
x
1(n+31)=(x
1(n+3)+x
1(n))mod 2 (1)
x
2(n+31)=(x
2(n+3)+x
2(n+2)+x
2(n+1)+x
2(n))mod 2
Wherein, N
c=1600, First ray is initialized as x
1(0)=1, x
1(n)=0, n=1,2 ..., the 30,2nd sequence by
Determine.In LTE, URS corresponding for initialization the 2nd sequence value by
determine.Produce real part and the imaginary part of URS sequence according to above formula respectively, and carry out QPSK modulation.Can find out, in LTE, the design of URS sequence comprises following characteristics: 1., and each subframe reinitializes; 2., mapping mode is that frequency domain is preferential, and the length of pilot frequency sequence is: the RB number that in every RB, DMRS expense * dispatches; 3., QPSK modulation.
In LTE-Advance system, introduce multiple DMRS port, and between port, there is the mode of code division multiplexing, therefore there are differences with LTE R8 producing method demand.The present invention is directed to the method for designing that this problem proposes DMRS sequence in lte-a system.
For in correlation technique to the problem of the demodulation more complicated of data reference symbol sequence, at present effective solution is not yet proposed.
Summary of the invention
For the demodulation more complicated of data reference symbol sequence problem and the present invention is proposed, for this reason, main purpose of the present invention is the method and the device that provide a kind of demodulating data reference mark sequence, to solve the problem.
To achieve these goals, according to an aspect of the present invention, a kind of method of demodulating data reference mark sequence is provided.
According to the method for demodulating data reference mark sequence of the present invention, wherein, when producing the pilot frequency sequence of data demodulates pilot tone, between same collaborative bunch each corresponding community, adopt identical data demodulates pilot frequency sequence production method.
Preferably, between same collaborative bunch each corresponding community, identical data demodulates pilot frequency sequence production method is adopted to comprise: to be same collaborative bunch defining virtual cell ID; Between each community in same collaborative bunch, all produce demodulation data reference signal sequence according to virtual subdistrict mark.
Preferably, virtual subdistrict mark defines based on subscriber equipment.
Preferably, virtual subdistrict identifies side Network Based to define.
Preferably, when the pilot frequency sequence of data demodulates pilot tone produces, between the layer carrying out code division multiplexing, demodulating data reference mark sequence is produced according to different initialization modes; Carry out between frequency division multiplexing or time-multiplexed layer, adopting identical initialization mode to produce demodulating data reference mark sequence.
Preferably, method comprises: carry out initialization to sequence, obtains the sequence after initialization; The pilot tone binary sequence of Len req is produced according to the sequence after initialization; Pilot tone binary sequence is modulated.
Preferably, modulation is carried out to pilot tone binary sequence and comprises: carry out Quadrature Phase Shift Keying QPSK or binary phase shift keying BPSK according to demodulation pilot frequency sequence and modulate, thus obtain demodulating data reference mark sequence.
To achieve these goals, according to a further aspect in the invention, a kind of device of demodulating data reference mark sequence is provided.
This device can be subscriber equipment, a kind of according to subscriber equipment of the present invention, and wherein, subscriber equipment, when producing the pilot frequency sequence of data demodulates pilot tone, between same collaborative bunch each corresponding community, adopts identical data demodulates pilot frequency sequence production method.
Preferably, subscriber equipment comprises: initialization module, for carrying out the initialization of sequence, obtains the sequence after initialization; Generation module, for producing the pilot tone binary sequence of Len req according to the sequence after initialization; Modulation module, for modulating according to pilot tone binary system, obtains demodulating data reference mark sequence.
Pass through the present invention, adopt when producing the pilot frequency sequence of data demodulates pilot tone DMRS, between same collaborative bunch each corresponding community, adopt identical DMRS method for generating sequence, solve the problem of the demodulation more complicated of data reference symbol sequence, and then reach the effect can carrying out the demodulation of data reference symbol sequence easily.
Embodiment
Functional overview
Consider the demodulation more complicated of data reference symbol sequence in correlation technique, embodiments provide a kind of method and device of demodulating data reference mark sequence.The method comprises: when producing the pilot frequency sequence of data demodulates pilot tone DMRS, between same collaborative bunch each corresponding community, adopts identical DMRS method for generating sequence.
It should be noted that, when not conflicting, the embodiment in the application and the feature in embodiment can combine mutually.Below with reference to the accompanying drawings and describe the present invention in detail in conjunction with the embodiments.
Embodiment of the method
Method according to the demodulating data reference mark sequence of the embodiment of the present invention comprises the following steps:
When producing the pilot frequency sequence of data demodulates pilot tone DMRS, between same collaborative bunch each corresponding community, adopt identical DMRS method for generating sequence.
Impact on sequences Design this embodiment to exist cooperation owing to having taken into full account between the multiplex mode problem of demodulating data reference symbol and community time, solves the problem to the demodulation more complicated of data reference symbol sequence in correlation technique.This embodiment proposes the method for designing of demodulating data reference mark sequence in a kind of lte-a system.
Fig. 2 is the flow chart of the method for preferred demodulating data reference mark sequence according to the embodiment of the present invention, and as shown in Figure 2, the method comprises the following steps:
Step S201 is same collaborative bunch defining virtual community ID;
Step S202, between each community in same collaborative bunch, all produces demodulation data reference signal sequence according to virtual subdistrict ID.
Wherein, virtual subdistrict ID can define based on UE.Also can define side Network Based.
Preferably, side Network Based refers to the cooperative cluster that network side definition is fixing, and namely static or semi-static division which community good belongs to one bunch, and semi-static be each bunch of distribution virtual ID; And when defining based on UE, refer to and dynamic define different bunches, bunch dynamic change that different UEs is corresponding for each different UE.
The preferred embodiment provides between same collaborative bunch each corresponding community, adopts the specific embodiments of identical DMRS method for generating sequence.
Preferably, when the pilot frequency sequence of DMRS produces, between the layer carrying out code division multiplexing, demodulating data reference mark sequence is produced according to different initialization modes; Carry out between frequency division multiplexing or time-multiplexed layer, adopting identical initialization mode to produce demodulating data reference mark sequence.
Preferably, above-mentioned method comprises: carry out initialization to sequence, obtains initialization sequence; The pilot tone binary sequence of Len req is produced according to initialization sequence; Pilot tone binary sequence is modulated.Wherein, modulation is carried out to pilot tone binary sequence and comprises: carry out QPSK or BPSK modulation according to demodulation pilot frequency sequence, thus obtain demodulating data reference mark sequence.
Preferably, the pilot tone binary sequence of Len req in resource is produced according to initialization sequence and the resource block size that is scheduled for transmission PDSCH data.
The preferred embodiment provides a kind of specific embodiments of the method for demodulating data reference mark sequence.
In LTE Rel8, for generation of URS (UE-specific reference signal) pseudo random sequence x
2n the initialization of () is determined by three parameters, three parameters are respectively N
iD cell(community ID identifies),
(subframe sequence number), n
rNT1(user ID mark).The detailed process producing user's specific pilot sequence in LTE Rel8 for: first according to the resource block number N for transmitting PDSCH (physical downlink share channel) that user dispatches
rB pDSCH, produce the real part of demodulation reference mark sequence and binary pseudo-random sequence corresponding to imaginary part according to following mode: c (2m) and c (2m+1)
Wherein the generation of c (n) produces based on 31 long gold sequences, concrete mode be shown below into:
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 (1)
x
2(n+31)=(x
2(n+3)+x
2(n+2)+x
2(n+1)+x
2(n))mod2
Wherein First ray x
1initialization value be x
1(0)=1, x
1(n)=0, n=1,2 ..., the 30,2nd sequence x
2by
Determine, in LTE Rel 8, c
initvalue is at community ID, and when subframe sequence number and user ID are determined, value is
therefore according to c
initthe 2nd sequence x can be obtained
2initialization value.Thus and then the N of scheduling can be obtained
rB pDSCHthe binary sequence c (2m) of Len req and c (2m+1) on Resource Block.And and then according to formula
Obtain the specific reference sequences of user after ovennodulation.As can be seen from upper surface analysis, the generation of sequence is by c
initdetermine completely.
In lte-a system, based on above-mentioned mode, the producing method of sequence is transformed, transforms mainly for c
initinitialization mode carry out.
Fig. 3 is the method schematic diagram of DMRS sequence generation according to the preferred embodiment of the invention, and based on the method for designing of LTE Rel8, this preferred embodiment provides a kind of method for designing of concrete demodulating data reference mark sequence, and concrete implementation step comprises:
Step 1: network side carries out the initialization of sequence, obtains c
init.
When carrying out initialization, the situation only having a layer (layer) is mainly considered in the initialization of LTE R8 URS, in lte-a system, in order to support multiple layers of transmission, need to introduce on its basis the design problem of the demodulation reference sequences considered in multiple layers of situation.Therefore, on the basis of LTE-R8 URS production method, can introduce and the sequence number parameter that (i.e. DMRS port sequence number) is relevant.Concrete, according to the multiplex mode of demodulation data reference symbol on each layer, determine the maximum number of layers of carrying out code division multiplexing, for the floor carrying out code division multiplexing carries out initialization with different sequence relevant parameters, and carry out can adopting between frequency division or time-multiplexed layer identical or different initialization sequence, preferable case be adopt identical initialization sequence between frequency division or time-multiplexed layer.Concrete, if total number of layers is L, corresponding each sequence number is respectively l
0..., l
i... l
l-1, L layer is divided into K group, and often organizes and comprise identical number of layers as far as possible, and adopt code division multiplexing between each layer often in group, between the layer of different group, adopt frequency division or time division multiplexing.Then when carrying out initialization, introduce the factor of n lID that layer is relevant, or with nlID to the n in LTE-Rel8
rNTIreplace.The maximum layer number of supposing to carry out code division multiplexing is M, then nlID obtains value is nlID=0,1 ..., M-1.The nlID that different layers between same group that carries out code division multiplexing is corresponding different respectively, between different groups, the layer that relative sequence number is identical in group is adopted and is carried out initialization in a like fashion.Such as: total number of layers is 8, and wherein { 1,2,3,4} layer carries out code division multiplexing, and { 5,6,7,8} layer carries out code division multiplexing, and carries out time-division or frequency division multiplexing between two groups.Then layer 1 and layer 5 adopt identical initialization mode, corresponding nlID=0; Layer 2 and layer 6 adopt identical initialization mode, corresponding nlID=1; Layer 3 and layer 7 adopt identical initialization mode, corresponding nlID=2; Layer 4 and layer 8 adopt identical initialization mode, corresponding nlID=3.
When initialization, when the layer between needing different groups adopts different sequences, the factor of n that group is relevant can be introduced
gid, n
gid=0 ... K-1.
When initialization, except considering to introduce to except sequence number relevant parameter, the parameter that the initialization in LTE Rel8 formula uses can be revised further and modify, in LTE-A, the cell ID parameter N in initialization
iD cellbe revised as virtual ID (for participating in a virtual ID of all cell definitions of transfer of data in the same cooperative cluster) N used when transmitting in the resource of dispatching
iD coMPCluster, when only having a community to participate in transfer of data, then N
iD coMPClusterdeteriorate to N
iD cell.
Step 2: according to initialized sequence, produces the demodulation pilot frequency binary sequence of Len req.
As shown in Figure 3, binary sequence can be produced by sequence generator.
When adopting QPSK, according to the mode defined in LTE Rel8, produce the binary sequence of real part and the binary sequence of imaginary part respectively.
When producing sequence, in LTE-A, the length of sequence, in inhomogeneous pilot tone pattern, produces the sequence of different length.When number of layers is less than or equal to 4, the demodulating data reference mark sequence length of generation should be 6
nR bPDSCH, wherein N
rB pDSCHfor the RB number for PDSCH transfer of data that dispatched users is distributed.When adopting QPSK modulation, corresponding binary sequence length is 12N
rB pDSCH; When adopting BPSK modulation, corresponding binary sequence length is 6N
rB pDSCH.
Step 3: QPSK or BPSK modulation is carried out to binary sequence, thus obtains demodulating data reference mark sequence.
In above-mentioned steps, arbitrary steps all independently belongs to of the present invention and comprises scope.In step 2, collaborative bunch refer to, network side is specific or UE is indirectly specific or participate in the node set of PDSCH transfer of data corresponding to certain UE directly.Virtual subdistrict ID is directly defined on collaborative bunch, also can be defined in the node set of PDSCH transfer of data corresponding to actual participation UE.The definition schematic diagram of virtual subdistrict as shown in Figure 4.
It should be noted that, in systems in which, each layer of correspondence demodulation data reference symbol antenna port is also a corresponding road demodulation data reference symbol.
Concrete, suppose that total number of layers is N=M*K, wherein M represents each number of layers of carrying out comprising in the group of code division multiplexing, and K represents the group data of code division multiplexing.When network side carries out the pseudo random sequence initialization of demodulation data reference symbol, in initialization procedure, add parameter nlID, nlID=0,1 ..., M-1.For each nlID produces pseudo random sequence respectively.Corresponding nlID initialization is used respectively between M the layer carrying out code division multiplexing.Meanwhile, in K group, adopt the pseudo random sequence that identical initialization mode produces.Such as total number of layers is 8, is divided into 2 groups, adopts code division multiplexing mode between each layer in same group, adopts the mode of time-division or frequency division multiplexing between different groups, then the number of layers that often group carries out code division multiplexing is 4, i.e. N=8, M=4, K=2.According to mode of the present invention, respectively when carrying out pseudo random sequence initialization, add parameter nlID.
Based on above-mentioned consideration, based on the producing method of LTE Rel8, add sequence number corresponding parameter in formula after, a kind of initialization mode can be revised as:
Or
wherein x and y represents any positive integer being more than or equal to 1.
Thus make the different layers in same code division multiplexing group (DMRS antenna port) adopt different demodulating data reference mark sequences.And the layer in different groups can use identical sequence.In above formula, parameter n
rNTIalso can delete, sequence is not changed with the change of user ID.
When also needing to adopt different initialization modes between the group of different code division multiplexing, the factor of n that group is relevant can be introduced
gid, then above formula becomes (when not considering user ID parameter):
Or
wherein x and y represents any positive integer being more than or equal to 1.
When considering CoMP (coordinated multi-point transmission and reception), further can by the N in above formula
iD cellbe revised as N
iD coMPCluster, wherein N
iD coMPClusterfor the virtual subdistrict ID that the one or more communities defined based on cooperative cluster above share.Now above formula becomes:
Or
Wherein the value of m is determined by the number of layers of carrying out code division multiplexing, and when the number of layers of code division multiplexing is 2, then the value that m obtains is 0 or 1, when the number of layers of code division multiplexing is n, then and m=0...n-1, in above formula, parameter n
rNTIequally also can delete, sequence is not changed with the change of user ID.
When also needing to adopt different initialization modes between the group of different code division multiplexing, the factor of n that group is relevant can be introduced
gid, then above formula becomes (when not considering user ID parameter)
Or
Under MU-MIMO pattern, due to the business that different user possibility is corresponding different, therefore for the resource size of different user scheduling is different, Fig. 5 is according to the preferred embodiment of the invention in MU-MIMO, the schematic diagram of the not reciprocity situation of user resources allocated size, in figure, the resource size of part dispatched users is 2RBs, and the scheduling resource size of some user is 3RBs, and also some user is scheduled as 4RB.If demodulation reference mark sequence carries out the design of demodulation pilot frequency sequence according to the resource size that user distributes, sharing between multiple user just cannot be realized.Such as according to user 1, the sequence that its demodulation reference mark sequence length produced is length corresponding to demodulation pilot frequency in 2 RB, and the sequence that the demodulation reference mark sequence length that user 5 produces is length corresponding to demodulation pilot frequency in 4 RB.Thus occur that the sequence that different layers is corresponding is different.Based on this, according to the granularity of scheduling, system can the N of cycle or aperiodicity configuration sequence foundation when producing
rB minnumber, and every N continuous again
rB minthe sequence that upper employing is identical, wherein N
rB minsize be more than or equal to 1 integer, therefore the length of sequence is: when number of layers is less than or equal to 4, and the length of demodulating data reference mark sequence is 6N
rB min; When number of layers is greater than 4, the length of demodulating data reference mark sequence is 3N
rB min.Now, the mapping mode of sequence as shown in Figure 6, at each N
rB minin RB, preferentially mapping at frequency domain, when mapping, carrying out on the RE of CDM, every layer adopts identical pseudo random sequence, and carrying out on each RE of CDM of being expanded by the mode of spread spectrum with CDM spreading code.What provide in figure is
When number of layers is 2, only have
the RE identified uses, for every one deck, and two RE adjacent in time domain
same demodulation pilot frequency sequence is adopted to be spread on RE adjacent in time domain by the orthogonal intersection that length is 2.When number of layers is 4, in figure
that identify is the RE that layer 1 and layer 2 take,
what identify is layer 3, the RE that layer 4 takies.
presentation layer 1, the RE couple of the multiplexing correspondence of layer 2,
presentation layer 3, the RE couple of the multiplexing correspondence of layer 4.When number of layers is 8,
what identify is and layer 1 that layer 2 carries out multiplexing layer, in embodiment, and corresponding { 1,2,5,7} layer.
what identify is and layer 3 that layer 4 carries out multiplexing layer, in embodiment, and corresponding { 3,4,6,8}.
Device embodiment
Fig. 7 is the schematic diagram of the subscriber equipment according to the embodiment of the present invention, and as shown in Figure 7, this subscriber equipment, when producing the pilot frequency sequence of DMRS, between same collaborative bunch each corresponding community, adopts identical DMRS method for generating sequence.
Preferably, this subscriber equipment comprises: initialization module 10, for carrying out the initialization of sequence, obtains the sequence after initialization; Generation module 20, for producing the pilot tone binary sequence of Len req according to the sequence after initialization; Modulation module 30, for modulating according to pilot tone binary system, thus obtains demodulating data reference mark sequence.
Impact on sequences Design this embodiment to exist cooperation owing to having taken into full account between the multiplex mode problem of demodulating data reference symbol and community time, solves the problem to the demodulation more complicated of data reference symbol sequence in correlation technique.This embodiment proposes the method for designing of demodulating data reference mark sequence in a kind of lte-a system.Use the subscriber equipment of this embodiment can realize the method for above-mentioned demodulating data reference mark sequence, the device of this subscriber equipment known and demodulating data reference mark sequence.
As can be seen from the above description, present invention achieves following technique effect:
(1) orthogonal pilot frequency sequence is adopted between the one group of layer carrying out code division multiplexing, under code division multiplexing mode can be avoided, the destruction of the orthogonality between different layers.
(2), in the resource called for same user, distribute fixed bed number, and adopt identical resource mapping method, be convenient to the identification of user to number of layers, and the identification to pattern, reduce the complexity of control signal design and UE Receiver Design.
(3) under MU-MIMO pattern, in the resource of distributing for user scheduling, distribute the layer of fixing sequence number, be convenient to the notice of control signal, and UE is to the identification of layer mapping mode.
(4) in CoMP, the different districts in same collaborative bunch adopts identical DMRS sequence producing method, is conducive to UE and adopts identical receiver architecture under CoMP JT pattern and non-CoMP pattern, thus simplify the complexity of UE Receiver Design.
Obviously, those skilled in the art should be understood that, above-mentioned of the present invention each module or each step can realize with general calculation element, they can concentrate on single calculation element, or be distributed on network that multiple calculation element forms, alternatively, they can realize with the executable program code of calculation element, thus, they can be stored and be performed by calculation element in the storage device, or they are made into each integrated circuit modules respectively, or the multiple module in them or step are made into single integrated circuit module to realize.Like this, the present invention is not restricted to any specific hardware and software combination.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.