WO2011153859A1

WO2011153859A1 - Mapping method and system for demodulation reference signal

Info

Publication number: WO2011153859A1
Application number: PCT/CN2011/072012
Authority: WO
Inventors: 孙云锋; 张文峰; 郭森宝; 张峻峰
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-06-07
Filing date: 2011-03-21
Publication date: 2011-12-15
Also published as: CN102271109B; CN102271109A

Abstract

A mapping method and system for Demodulation Reference Signal are provided in the present invention. Wherein the method includes the following steps: on each Orthogonal Frequency Division Multiplexing (OFDM) symbol mapped by Demodulation Reference Signal (DMRS), different orthogonal mask mapping modes are equably distributed to different DMRS resource units of the OFDM symbol; the orthogonal mask mapping of each layer in a physical resource block guarantees orthogonality in the time domain, simultaneously in the frequency domain of said physical resource block, the orthogonal mask mapping of each layer at least guarantees that each current DMRS resource unit forms orthogonality relation with one or more resource units of the front or back consecutive resource units bearing DMRS. Using the method and system of the present invention, when rank >2, both the aspect of avoiding imbalance of transmission power and the aspect of guaranteeing orthogonality in time domain and frequency domain can be considered.

Description

Method and system for mapping demodulation reference symbols

The present invention relates to the field of communications, and in particular, to a mapping method and system for a Demodulation Reference Signal (DMRS) in a high rank case. Background technique

High-order multi-antenna technology is one of the key technologies of the LTE-A (Long Term Evolution Advanced) system to increase the system transmission rate. The advanced long-term evolution can also be expressed as LTE-Advanced. In order to implement channel quality measurement and data demodulation after introducing high-order multi-antenna technology, LTE-A systems respectively define two types of pilot symbols: DMRS and Channel State Information-Reference Signal (CSI-RS, Channel State Information- Reference Signal) The DMRS is used for demodulation of a Physical Downlink Shared Channel (PDSCH). CSI-RS for CSI (channel state information) measurement, used for channel quality indicator (CQI, Channel Quality Indicator), precoding matrix indicator (PMI), hierarchical indicator (RI, Rank Indicator), etc. Only on the top. The structure of the above two types of pilot symbols can be used to support new technical features of LTE-A such as CoMP (Coordinated Multi-Point), spatial multiplexing, and the like.

In LTE, the common reference signal (CRS, common reference signal or cell specific reference signal) is used for pilot measurement, that is, all users use common pilots for channel estimation. When using this CRS, the transmitting end needs to additionally inform the receiving end of the data transmitted by the receiving end, which preprocessing method is used, and the pilot has a large overhead. In addition, in multi-user multi-input multi-output (MU-MIMO, multi-user multi-input multi-output), since multiple terminals use the same CRS, pilot orthogonality cannot be realized, so interference cannot be estimated.

In LTE-A, in order to reduce the overhead of pilots, CSI-RS and DMRS are separately designed. Since the DMRS and the data are processed in the same pre-processing manner, and the DMRS is mapped according to the available rank information of the corresponding channel of the scheduling user, the pilot overhead can be adaptively adjusted according to the rank information, so that in the case of a lower rank, The overhead of the pilot can be greatly reduced. The characteristics of the DMRS include: (1) terminal-specific, such as: the DMRS corresponding to a specific terminal and the data of the scheduling user are processed by the same precoding; (2) only exists on the network side, such as an enhanced base station (eNB) as data Transmission of the scheduled resources and layers; (3) On the network side, the DMRSs transmitted on different layers are orthogonal to each other.

Currently, in the case of Normal Cyclic Prefix (Normal CP, Normal Cyclic Prefix), the reference pattern of the formed DMRS mapping is as shown in FIG. 1a. When the rank is 1~2, DMRS resource mapping unit, and (layer) corresponding to the port two conductive layers through the length of a frequency of 2 orthogonal cover code (OCC, orthogonal cover code) multiplexed code codebook; _ra nk in the range of 3 to 4, on the basis of rank 1~2, through frequency division multiplexing (FDM, frequency divided multiplexing), a group of resource units shown by force increase port H, where {0, 1 } layer corresponds to 0 The resource unit, the {2, 3 } layer corresponds to the resource unit shown in the ,, and the pilot of the corresponding port of each group is code-multiplexed in the time domain by the OCC of length 2; When ~8, the pilot mapping is performed with the same resource unit as the rank 3~4, where the layer {0, 1 , 4, 6} corresponds to the resource unit shown, and the layer {2, 3, 5, 7 } corresponding to the resource unit shown, and using the OCC of length 4 for code division multiplexing in the time domain, the resource elements in the same rectangular frame in Figure la (RE, R The esource Element is an RE that performs code division multiplexing. When the rank is 5 to 8, the REs in the two rectangular frames connected by the black dashed line in the time domain are subjected to OCC code division multiplexing of length 4. It should be noted that the figure la is taken as an example of a physical resource block (PRB), and the mapping positions in different PRBs are the same. It should be noted that, in LTE R9 and LTE R10, the layer, corresponding to the port i + i -, will not be reiterated in the following description. Figure lb and Figure lc are DMRS mapping patterns for special subframes. The configuration of special subframes is shown in Table 1 below. Table 1 is the configuration table of special subframes. In Table 1, r _s is the sample week. Period, 7; =1/(15000x2048), DwPTS in Table 1 refers to a downlink pilot time slot; UpPTS refers to an uplink pilot time slot. Wherein, in the above figure, FIG. 1b, the legend 0 represents the DMRS of the layer 1 and the RE corresponding to the layer 2; the legend Ξ represents the DMRS of the RE corresponding to the layer 3 and the layer 4; the legend ^ represents the common reference signal; FIG. 11) ~ FIG. (;, in the legend, represents a guard interval. The special subframe refers to: a subframe for uplink/downlink switching in a time division duplex (TDD) system.

At the 3GPP 58bis conference, a method for generating a DMRS sequence in LTE R9 is proposed, as shown below:

r(m) = -^(l-2-c(2m)) + j-^=(\-2- c{2m + \)), m = 0,1,...,12. A ^DL — 1 ; Among them, generated by the 31-bit long Glod sequence, which is the general expression of c(2m) and c(2m + l) in the above formula; the way of production follows the way of LTER8, namely:

c(n) = {x _l (n + N _c ) + x ₂ (n + N _c )) mod2

_{ι ι} (η + 3ϊ) = (j (n + 3) + x _x (w)) mod2

x ₂ (n + 3l) = (x ₂ (n + 3) + x ₂ (n + 2) + x ₂ (n + l) + x ₂ (n)) mod2

In the above formula, the initial value of the m-sequence is the same as R8, which is: (0) = 1, («) = 0," = 1,2,...,30; The initial value of the m-sequence is in R9. It is determined by _Cinit = (ln _s /2"+ 1)· (2A + 1)· 2 ¹⁶ + n _scm , and ^ ⁼ ∑ ^χ 2«.2 ^; _CID indicates the parameter used to distinguish different users. The default value is 0. In MU-MIMO, " _SCID can take a value of 1.

Downlink transmission is a normal cyclic prefix Downlink transmission is an extended cyclic prefix

DwPTS UpPTS DwPTS UpPTS

The frame is on the line, the line is on the line, the line is on the line, the line is on the line, and the line is normal. The extension is normal. The extension is the loop prefix. The ring prefix is the ring prefix.

0 6592 · Γ ₈ 7680 · Γ ₈

1 19760.7; 20480.7;

2192.7; 2560.7;

2 21952.7; 2192· Γ ₅ 2560.7; 23040.7;

3 24144.7; 25600.7;

4 26336.7; 7680 · Γ ₈

5 6592 r _s 20480.7; 4384.7; 5120.7;

6 19760.7; 23040.7;

4384 · Γ ₈ 5120.7;

7 21952.7; - - -

8 24144.7; - - -

According to the existing generation manner of the pilot sequence of LTE R9, OCC processing is performed, and different masks correspond to different layers. When multiple layers are code-multiplexed, and the layers are orthogonal to each other, the corresponding sequences are the same before the multiple layers are processed by the OCC, so when the pilots processed by the OCC are pre-processed

5 encoding processing, on a given DMRS Orthogonal Frequency Division Multiplexing (OFDM) symbol, will be in some

The superposition of the pilot signals on the antenna port is enhanced, and the superposition of the pilot signals on the other antenna ports is canceled, which is called the problem of unbalanced transmission power. Especially when the rank is 5~8, the problem of this transmission power imbalance is more serious. Figure 2 shows a schematic diagram of the problem of unbalanced transmission power on different symbols generated by an OCC mapping when rank is 5~8, which can be seen from Figure 2.

10 to see: For port 7, when the precoding weight is W ₄ , the power of DMRS is all

Concentrated on OFDM symbol #6, and 0 on other OFDM symbols, resulting in no transmission power Balance, which is very unfavorable for the design of the antenna power amplifier. It should be noted here that the mapping processing of the OCC actually represents the mapping process of the DMRS corresponding to each port performing code division multiplexing. This paper is based on the mapping of OCC to achieve the purpose of mapping processing of DMRS.

For the mapping processing of the OCC, in order to avoid the imbalance of the transmission power, the mapping processing to the OCC is as follows: In 3GPP R9, an OCC mapping method for performing rotation mapping on layer 2 when the rank is 1 to 2 is defined, for example, As shown in FIG. 3, the above problem of transmission power imbalance is solved. However, the mapping method shown in Figure 3 only applies to the case where rank is 1~2; it is not applicable for higher ranks. Although the existing mapping scheme for OCC for rank > 2 already exists, there are still some shortcomings: Can not take into account the orthogonality of the guaranteed time-frequency domain in avoiding the transmission power imbalance, it can be seen that: The mapping scheme for OCC for Rank > 2 is not comprehensive and is not perfect, which may result in the inability to guarantee channel estimation performance and affect the mapped data transmission. At present, there is an urgent need for a mapping method and system suitable for DMRS with rank > 2, which can take care of avoiding transmission power imbalance and ensuring orthogonality in time-frequency domain. Summary of the invention

In view of this, the main object of the present invention is to provide a DMRS mapping method and system. When rank > 2, in terms of avoiding transmission power imbalance, it can be balanced with ensuring orthogonality of the time-frequency domain.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A mapping method for demodulating reference symbols, the method comprising:

Orthogonal Frequency Division Multiplexing (OFDM) symbols each having a Demodulation Reference Symbol (DMRS) are mapped, and different orthogonal mask mapping modes are uniformly allocated for different DMRS resource elements on the OFDM symbol;

An orthogonal mask mapping of each layer in a physical resource block, ensuring that the time domain is orthogonal and simultaneously in the frequency domain within the physical resource block, the orthogonal mask mapping of each layer at least guarantees each current DMRS resource The source unit forms an orthogonal relationship with one or more of the resource elements carrying the DMRS adjacent to or behind.

The resource unit of the current DMRS resource unit and the DMRS carrying the preceding or following is: a resource unit carrying the DMRS corresponding to the same code division multiplexing (CDM) group.

The method for uniformly allocating different orthogonal mask mapping manners for different DMRS resource units on the OFDM symbol includes: each port of the same CDM group, on different DMRS resource units of the same OFDM symbol; The vector form of the corresponding orthogonal mask weights of the port on the DMRS resource unit is different and is evenly distributed.

The method further includes: in the LTE R10 and subsequent evolved versions, the orthogonal mask mapping mode when the rank is >2, and the orthogonal mask mapping when the rank is 1~2 in the current LTE R9 is required. Way compatible;

The compatibility is as follows: When the rank>2, the orthogonal mask mapping mode of the port 7 and the port 8 is the same as the orthogonal mask mapping mode of the port 7 and the port 8 when the rank is 1~2.

When assigning different orthogonal mask mapping modes, the method further includes: for the ports of two different CDM groups, on the basis of compatibility, each port uses different orthogonal mask allocation manners or selects different ones. Orthogonal mask.

Wherein, the orthogonal mask with the length of 2 is set to _{w =} ( ^c ₌ ( _a 3⁄4 ); when the orthogonal mask with the length of 4 is set, the orthogonal mask mapping manner includes the following manners

Any one or combination of at least one:

Mode 1: When the rank is 3~4, the orthogonal mask mapping with length 2 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: The port {, _Ps } in group 1 is in the time domain. Adjacent two

In the case of (ab), port { p ₉ , A. } corresponds to (ba) ; or, port ft } in group 1 is at The vectors consisting of orthogonal mask weights corresponding to mapping on two adjacent DMRS resource units on the domain are respectively (b, in case port ₉ , _A. } corresponds to (ab);

Manner 2: When the rank is 5~8, the orthogonal mask mapping with length 4 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: Ports _Ps , _Pn , and } in group 1 are in the time domain. The quantities are (abc, port { p ₉ , _Pw , _Pl2 , } corresponds to (adeb), (cdab), (a -b -cd, , (ab -c -b); and port { p ₉ , p _L0 , p _l2 , p _l4 } are polled in the same way as ports p, , _Pll , ;; _Ci = 0, l, 2, 3 are row vectors, a, b, c, d represent the columns of the constructed matrix Vector.

A mapping system for demodulating reference symbols, the system comprising: a mapping unit, configured to uniformly allocate different orthogonal mask mapping manners for different DMRS resource units on an OFDM symbol on each OFDM symbol mapped with DMRS ; orthogonal mask mapping of each layer in a physical resource block, ensuring that the time domain is orthogonal while in the frequency domain within the physical resource block, the orthogonal mask mapping of each layer at least guarantees each current DMRS resource unit One or several of the resource elements carrying the DMRS adjacent to the front or the back constitute an orthogonal relationship.

The resource unit of the current DMRS resource unit and the DMRS that is adjacent to the preceding or following is: a resource unit that carries the DMRS corresponding to the same CDM group.

The mapping unit is further configured to allocate different orthogonal mask mapping modes for different DMRS resource units on the OFDM symbol, so that each port of the same CDM group has different DMRSs in the same OFDM symbol. On the resource unit, the vector forms of the corresponding orthogonal mask weights of the respective ports on the DMRS resource unit are different, and are uniformly distributed.

The mapping unit is further used for the orthogonal mask mapping mode, and the orthogonal mask mapping mode with rank>2 in LTE R10 and subsequent evolved versions is required, and the current LTE R9 is used. The rank is 1 to 2 when the orthogonal mask mapping mode is compatible; the compatible package In the case of rank>2, the orthogonal mask mapping mode of port 7 and port 8 is the same as that of port 7 and port 8 when rank is 1~2.

The mapping unit is further configured to use a different orthogonal mask allocation manner or select a different orthogonal mask for each port of the two different CDM groups on a compatible basis.

The mapping unit is further configured to set an orthogonal mask of length 2 to w

The orthogonal mask mapping manner includes any one or a combination of at least one of the following modes: Mode 1: When the rank is 3~4, the orthogonal mask mapping with length 2 is used, and two CDM groups are used. The corresponding orthogonal mask mapping manner includes: Ports { , _Ps } in group 1 are adjacent to each other in the time domain.

In the case of (ab), the port { ρ ₉ , _Λ . } Corresponding to (ba); or, the vector consisting of the orthogonal mask weights corresponding to the ports in group 1 mapped on two adjacent DMRS resource units in the time domain is (b, in case port Ρ9) _Λο } corresponds to (b);

Manner 2: When the rank is 5~8, the orthogonal mask mapping with length 4 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: Ports _Ps , _Pn , and } in group 1 are in the time domain. The quantities are respectively (in the case of abc, ports { p ₉ , _Pw , _Pl2 , _Λ4 } correspond to (adeb), (cdab), (a -b -cd, , (ab -c -b); and port { p ₉ , p _l0 , p _l2 , p _l4 } are polled in the same way as ports p, , _Pll , ;; _Ci = 0, l, 2, 3 are row vectors, a, b, c, d are represented by the matrix Column vector.

The present invention allocates different orthogonal mask mapping modes for different DMRS resource units on the OFDM symbol on each OFDM symbol mapped with DMRS; orthogonal mask mapping of each layer in a physical resource block ensures Time domain orthogonal to the frequency domain within the physical resource block The orthogonal mask mapping of each layer at least ensures that each current DMRS resource unit forms an orthogonal relationship with one or several of the resource elements of the DMRS that are adjacent to or behind.

With the present invention, in the case of rank > 2, in terms of avoiding transmission power imbalance, it is possible to balance the guarantee of the time-frequency domain orthogonality. DRAWINGS

The figures la, lb, and lc are the mappings of the DMRS in the LTE R10 under the normal cyclic prefix, respectively;

2 is a schematic diagram of a transmission power imbalance on different OFDM symbols due to improper OCC mapping;

FIG. 3 is an OCC mapping manner corresponding to layer 0 and layer 1 in the existing LTE R9;

4 is a diagram showing an OCC of the present invention having a length of 2 under a normal cyclic prefix according to Embodiment 1 of the present invention;

Schematic diagram of OCC mapping mode;

5 is a schematic diagram of a BPSK-based OCC mapping manner according to Embodiment 2 of the present invention; FIG. 6 is a schematic diagram of a BPSK-based OCC mapping manner according to Embodiment 3 of the present invention; FIG. 7 is a schematic diagram of orthogonal phase factor processing according to Embodiment 4 of the present invention; Schematic diagram of OCC mapping. detailed description

The basic idea of the present invention is to allocate different orthogonal mask mapping modes for different DMRS resource units on an OFDM symbol on each OFDM symbol mapped with DMRS; orthogonality of layers in one physical resource block Mask mapping, ensuring that the time domain is orthogonal while the frequency domain in the physical resource block, the orthogonal mask mapping of each layer at least guarantees that each current DMRS resource unit is adjacent to the preceding or following DMRS resources. One or several of the elements form an orthogonal relationship.

The implementation of the technical solution will be further described in detail below with reference to the accompanying drawings.

The solution of the present invention is a perfection of the existing DMRS mapping scheme of rank > 2 The mapping processing of the OCC in the scheme is applicable to the mapping of DMRS when rank > 2, and the avoidance of transmission power imbalance in rank > 2, and the orthogonality of the guaranteed time-frequency domain can be considered. The key difference between the present invention and the prior art is: in addition to solving the problem of transmission power imbalance on different OFDM symbols, and taking into account the time-frequency domain orthogonality, that is, ensuring orthogonal characteristics in the time domain as shown in FIG. On the basis of the present invention, the present invention can simultaneously ensure orthogonal characteristics in the frequency domain.

Compared with the prior art, the existing mapping scheme for OCC applicable to rank > 2 is not comprehensive and is not perfect, which will eventually result in the inability to guarantee channel estimation performance and affect the mapped data transmission. After the mapping scheme of the present invention is used, the mapped data is transmitted, and the data transmission is performed. Since the mapping processing avoids the imbalance of the transmission power, the existing mapping scheme can be finally avoided to be caused by the mapped data transmission. influences.

A mapping method of DMRS mainly includes the following contents:

La, uniformly mapping different OCC mappings on different DMRS REs on the OFDM symbol on each mapped DMRS OFDM symbol;

Lb, the OCC mapping of each layer in a PRB ensures that the time domain is orthogonal, and the OCC mapping of each layer in the frequency domain within one PRB ensures that at least each current DMRS RE is adjacent to the preceding or following DMRS. One or several of the REs constitute an orthogonal relationship.

It should be pointed out here that: With the scheme of la, the rank > 2 can avoid the problem of unbalanced transmission power. Using the lb scheme, on the basis of ensuring the orthogonal characteristics in the time domain in a PRB, the orthogonal characteristics can be ensured in the frequency domain at the same time, which is simply: simultaneously ensuring that the time-frequency domain is orthogonal. Since the two-dimensional orthogonality of the time-frequency can be realized within one PRB, the estimation performance of the channel can be improved.

Further, in the lb, the current DMRS RE and the RE that carries the DMRS adjacent to the previous or subsequent DMRS are: REs carrying the DMRS corresponding to the same code division multiplexing (CDM) group.

Further, in la, uniform distribution on different DMRS REs on the OFDM symbol Different OCC mapping modes include: Each port of the same CDM group is on a different DMRS RE of the same OFDM symbol, and the different vector forms formed by the corresponding 0CC weights of each port on the DMRS RE are different, and are uniformly hooked. Using the scheme here, randomization of peak power can be achieved on the basis of time-frequency two-dimensional orthogonality.

Further, in the LTE R10 and subsequent evolved versions, the mapping mode of the OCC in the case of the rank > 2 needs to be compatible with the mapping mode of the rank1~2 defined in the current LTE R9, specifically: the port 7 when the rank is >2. The mapping mode of OCC with port 8 is the same as that of port 7 and port 8 when rankl~2. With the solution here, it has good backward compatibility and can be compatible with the design of port 7 and port 8 in LTE R9.

Further, for ports of two different CDM groups, on the basis of ensuring compatibility, each port uses a different OCC mapping mode or selects a different OCC.

Specifically, set the length 0 to 0< (set the OCC of length 4 to

However, it is not limited to the selection of the above OCC and the length described above, and the OCC mapping method includes any one or a combination of at least one of the following forms:

Mode 1: When the rank is 3~4, the OCC mapping with length 2 is used. The corresponding OCC mapping modes of the two CDM groups include: Ports in group 1 are mapped on two adjacent DMRS REs in the time domain. When the vector consisting of the OCC weights is (ab), the port { P ₉ , o } corresponds to ip a); or, the port { , p _s } in group 1 is adjacent in the time domain. The vectors consisting of OCC weights corresponding to the mapping on the two DMRS REs are (b, in case port ₉ , _Λ .} corresponds to (b).

Manner 2: When the rank is 5~8, the OCC mapping of length 4 is used. The mapping mode of the OCC used by the two CDM groups is as follows: Ports _P , _Pn , } in group 1 are in the time domain. When the vector consisting of the OCC weights corresponding to the two groups of adjacent DMRS REs is (abc <i), the ports { p ₉ , p _w , p _u , ρ ₁₄ } correspond to each other (α dcb, {cdab, {a -b - c <i ), or (ab - c - b) ', and the port { p ₉ , p _l0 , p _u , ;3⁄4 } and port { , P% ' _Pn , }釆Polling in the same way. Using the scheme here, the interference of DMRS RE between two CDM groups can be suppressed during channel estimation. Because different weights are used, interference can be suppressed. Where c. i = 0, 1, 2, 3 are row vectors, and a, b, c, d represent the column vectors of the matrix composed of _Ci . Further, different orthogonalization mats w and orthogonalization processing for different dimensional directions are respectively designed for the time domain and the frequency domain direction, wherein / represents the length of the orthogonal processing sequence in the time domain direction, and κ represents the frequency domain. Or orthogonal processing sequence length in other dimension directions.

Further, a plurality of orthogonalization matrices c3⁄4 may also be designed in the frequency domain. ,... : , Different orthogonalization matrices are used between adjacent PRBs.

The specific mapping method described in the solution of the present invention will be described below by way of specific embodiments. In the following analysis, the DMRS sequence is taken as an example of r(m), and the mapping pattern of the DMRS is described by taking the pattern of the normal subframe under the normal cyclic prefix in R10 as an example, but in practice, it is not limited to these assumptions.

Embodiment 1:

This embodiment provides a processing method for DMRS mapping at rank3~4. Based on the design method of OCC mapping for port 7 and port 8 in LTE R9, port 9 and port 10 are mapped in different ways. As shown in FIG. 4, the OCC codes used by port 7 and port 8 correspond to (0 a) = respectively on k and k+6 of the DMRS carrier adjacent to the group (such as the picture resource unit portion in FIG. 4). ( ¹ ) Port 9 and port 10 are in the group (as shown in Figure 4).

1 — 1 1 1 example resource unit part) adjacent DMRS carriers k+1 and k+6 respectively correspond to (p a) =

1 1

(\ 1

And (fl b) - , then it can be seen from the figure that the mapping method is not only adjacent in the time domain.

1 - 1 The two OFDM symbols are orthogonal, and the adjacent two DMRS REs corresponding to the same group in the frequency domain are also orthogonal to each other (inter-orthogonal to each other). Taking the demodulation reference sequence as an example, the mapping formula corresponding to port 7 and port 8 is expressed as: a)

among them,

'/'mod 2 + 2 Special subframe configuration is 3, 4, 8 in Table 1

Rmod 2 + 2 + 3 ^72” When the special subframe is configured as 1, 2, 6, 7 in Table 1,

/'mod 2 + 5 normal sub-frame condition

0, 1, 2, 3 even time slots, and special subframes are configured as 1, 2, 6, and 7 in Table 1.

0,1 even time slot, and when the special subframe is configured as the case other than 1, 2, 6, 7 shown in Table 1,

2,3 odd time slots, and special subframes are configured as shown in Table 1, except for cases 1, 2, 6, 7 m'= 0,1,2

In the formula, p denotes the port number, N ' ^DL denotes the maximum downlink bandwidth characterized by the number of PRBs, and the PRB table 'is shown in the first one? Mapping within 1^. For the mapping between port 9 and port 10:

The value of S is:

Alternatively, it can be set to:

f(-l)" ^s if p = 9

Where ^ is the slot number, Example 2:

This embodiment provides a processing method of DMRS mapping. Also in the mapping process, compatibility with port 7 and port 8 in R9 is considered. FIG. 5 is a schematic diagram corresponding to the embodiment, wherein the port {7, 8, 11 , 13 } is a code division multiplexing group, as shown in the figure of FIG. 5, the resource unit, port {9, 10, 12, 14} is another code division multiplexing group as shown in the picture resource unit part of Fig. 5. In Figure 5, . , b, c, d respectively represent different orthogonal vectors formed by OCC, for example, using walsh sequence, it can be expressed as: w ₄ \ abcd] ;

Show, · OCC. As can be seen. , b, c, d represent four sequences that are orthogonal to each other. It should be noted that, in practical applications, this embodiment may use a partial port in each CDM multiplexing group. In the OCC mapping mode shown in FIG. 5, not only is the orthogonality in the time domain direction of each CDM grou (the different ports correspond to different OCCs, or the rotation of the OCC) but also between two adjacent subcarriers. For example, the corresponding OFDM symbol index is 5, 6, the four DMRS REs on the kth and k+6th carriers are orthogonal; the OFDM symbol index is 5, 6, the k+11 and the k+13 four DMRS RE Orthogonal. Similarly, the demodulation reference sequence is m), and the mapping formula corresponding to each port is expressed as:

+ 3. M _prb + m' ) , where,

If P = 7 or 9

If P = 8

If P = 10

If P = l l

If p = 12 or 13

If _P = 14

k = 5

'mod 2 + 2 special subframe configuration for 3, 4, 8 cases in Table 1

'mod 2 + 2 + 3 ^72' special subframe configuration in the case of 1, 2, 6, 7 in Table 1

'mod 2 + 5 normal subframe condition

0,1 even time slot, and when the special subframe is configured as a table, the case other than 1, 2, 6, 7

2,3 odd time slots, and when the special subframe is configured as a table, the case other than 1, 2, 6, 7

m'= 0,1,2

It can be seen from the analysis in FIG. 5 and the above that the scheme can implement orthogonality between two carriers in the frequency domain in addition to orthogonality in the time domain. In order to realize 2-dimensional orthogonality of each carrier, it is required to be in the frequency domain. The two PRBs are combined.

Embodiment 3:

This embodiment provides a method of processing another DMRS mapping. Also in the mapping process, compatibility with port 7 and port 8 in R9 is considered. This embodiment uses all carriers in each PRB The 2-dimensional orthogonality is the optimization goal. At the same time, the peak power randomization problem on different OFDM symbols is guaranteed to the maximum extent. FIG. 6 is a schematic diagram corresponding to the embodiment, in which the port {7, 8, 11 , 13 } is still a code division multiplexing group, as shown in the figure of FIG. 6 , the resource unit, port {9, 10 , 12, 14} is another code division multiplexing group as shown in the picture resource unit part of Fig. 6. In the picture, . , b, c, d respectively represent different orthogonal vectors formed by OCC, and also take walsh sequence as an example, which is expressed as: w ₄ abed] ', where _Ci represents the first

OCC. As can be seen. , b, c, d represent four sequences that are orthogonal to each other. It should be noted that, in practical applications, this embodiment may use a partial port in each CDM multiplexing group.

As can be seen from Fig. 6, in addition to the orthogonal relationship in the time domain, within a PRB, the intermediate carriers are orthogonal to each other in the frequency domain before and after the carrier. As shown in the figure, the PRB corresponding to the carrier k to the carrier k+12 is taken as an example. In each slot (slot), the OFDM symbol index 5, 6, the carrier k and the carrier k+6 correspond to four REs. The relationship, and the carrier k+6, in turn, constitutes an orthogonal relationship with the four REs corresponding to the carrier k+11. Therefore, the carriers in each PRB can form a 2-dimensional orthogonality within one PRB.

Similarly, the demodulation reference sequence is m), and the mapping formula corresponding to each port is expressed as

= s · r (3 · l'-N ' ^DL + 3 · « _PRB + m' ) , where, in this embodiment, the value of port s in the first CDM group is:

(-1)"

(- 1)

(— l)" ^{s+ +} L )/2" if p = 13

5 · m'+N^ · n _PRB + 1

'/'mod 2 + 2 Special subframe configuration is 3, 4, 8 in Table 1

Rmod2 + 2 + 3^72" When the special subframe is configured as 1, 2, 6, 7 in Table 1,

If

/'mod 2 + 5 normal sub-frame condition

0,1 even time slot, and when the special subframe is configured as a table, the case other than 1,2, 6, 7

2,3 odd time slots, and the special subframe is configured as a table punch, except for cases other than 1,2, 6, 7 m'= 0,1,2

The value of port S in the second CDM group is

It is also possible to use the same OCC mapping as the port of the first CDM group, at this time ports 9 ⁷ , 10^8 , 12^11 , 14 13 . Or the second CDM group uses other forms, but remains the same as the first CDM group in a round-robin manner.

It should be noted that, in practical applications, the orthogonal codes represented by a, b, c, d are not limited to the BPSK-based format.

Embodiment 4:

In this embodiment, on the basis of ensuring that port 7 and port 8 are compatible with LTE R9, two or more sets of orthogonal matrices are respectively designed for orthogonal processing in the time domain and the frequency domain. In this embodiment, the time domain is still an example of an orthogonal matrix based on a walsh sequence, but is not limited thereto. If A, B, C, and D are 2x2 matrices, they are moments.

The four diagonal matrices of the array. At the same time, based on the compatibility of LTER9, another K-dimensional orthogonal matrix is designed. The length of K is determined by the orthogonal length of the frequency domain. In this embodiment, K=4 is taken as an example. And frequency Domains can implement orthogonal considerations within the same PRB. At the same time, the two adjacent carriers in the frequency domain and the same design method, as shown by the real rectangular frame in FIG. 7, can also select different second-dimensional modes in practical applications.

In the present embodiment, for convenience of explanation, only a group of CDM multiplexing groups corresponding to the legend resource unit will be described. For the resource unit portion of the legend, the technician can obtain analogy.

In this embodiment, in order to be compatible with LTE R9, and to achieve continuous orthogonality between two consecutive DMRS carriers, two two-dimensional orthogonal matrices 0 ₄ and 0 ₄ are respectively designed. Based on the design of LTE R9, the orthogonal matrices on adjacent carriers are:

Compatible, the first two lines of 0 ₄ and 0 ₄ are designed to satisfy ^ 0» ] and

4 time slots (

( ns=l ),

It is a phase factor with an amplitude of one and satisfies 0 ₄ and 0 _{4 to} form an orthogonal matrix. For example, in Figure 7 -* Wj = e

^W 2 in order to implement the carrier

Between the orthogonal transitions, 0 ₄ and 0 _{4 are used} on adjacent DMRS carriers in a rotating manner.

In the present embodiment, only a design method of 0 ₄ and 0 ₄ is given. Actually, the design method is not limited thereto.

Of course, in this embodiment, in order to implement 2-dimensional orthogonality in one PRB, The limitation is as follows: In the embodiment, the two DMRS carriers in the same CDM group and the four REs corresponding to the adjacent OFDM symbols are orthogonalized in the second dimension. In practical applications, the limitation is not limited thereto.

A DMRS mapping system, the system includes a mapping unit, and the mapping unit is configured to uniformly allocate different orthogonal mask mapping modes for different DMRS resource units on the OFDM symbol on each OFDM symbol mapped with DMRS; Orthogonal mask mapping of each layer in the physical resource block, ensuring that the time domain is orthogonal and simultaneously in the frequency domain within the physical resource block, the orthogonal mask mapping of each layer at least guarantees each current DMRS resource unit and the front Or one or more of the resource elements that are adjacent to the DMRS that are adjacent to each other constitute an orthogonal relationship.

Here, the system may further include a transmission unit configured to transmit the mapped data for data transmission.

Here, the resource unit of the current DMRS resource unit and the adjacent DMRS adjacent to the DMRS is: a resource unit carrying the DMRS corresponding to the same CDM group.

Here, the mapping unit is further configured to allocate different orthogonal mask mapping modes for different DMRS resource units on the OFDM symbol, so that each port of the same CDM group has different DMRS resources in the same OFDM symbol. On the unit, the vector forms of the corresponding orthogonal mask weights of the respective ports on the DMRS resource unit are different, and are evenly distributed.

Here, the mapping unit is further configured to use the orthogonal mask mapping mode, and it is necessary to ensure that in the LTE R10 and subsequent evolved versions, the orthogonal mask mapping mode at rank>2 is compared with the current rank in LTE R9. The orthogonal mask mapping mode is compatible with 1~2; the compatibility includes: orthogonal mask mapping mode of port 7 and port 8 when rank>2 and port 7 and port 8 when rank is 1~2 The orthogonal mask mapping is the same.

Here, the mapping unit is further used for ports of two different CDM groups, on a compatible basis, each port uses a different orthogonal mask mapping manner or selects a different orthogonal mask.

Here, the mapping unit is further configured to set the orthogonal mask of length 2 to When the orthogonal mask of degree 4 is , the orthogonal mask mapping manner includes

Any one or combination of at least one of the following:

Manner 1: When the rank is 3~4, the orthogonal mask mapping with length 2 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: The port {, _Ps } in group 1 is in the time domain. Adjacent two

In the case of (ab), port { p ₉ , A. } corresponding to (ba); or, when the port in group 1 is mapped on the two adjacent DMRS resource units in the time domain, the vector consisting of orthogonal mask weights is (b Ω), Port P9 _Ao } corresponds to ( &);

Manner 2: When the rank is 5~8, the orthogonal mask mapping with length 4 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: Ports _Ps , _Pn , and } in group 1 are in the time domain. The quantities are respectively (in the case of abc, the ports { p ₉ , _Pl0 , _Pn , _{Ρΐ 4} } correspond to (α deb) , (cdab ) ^ (a — b — c <i), or (ab -c -b); { p ₉ , p _l0 , p _u , p _l4 } are polled in the same way as port ft ' Pn ' 。 _Ci , · = 0,1,2,3 are row vectors, a, b, c, d The column vector of the matrix formed by.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A mapping method for demodulating reference symbols, the method comprising: differentiating on an OFDM symbol on each orthogonal frequency division multiplexing (OFDM) symbol to which a demodulation reference symbol (DMRS) is mapped The DMRS resource unit uniformly allocates different orthogonal mask mapping modes;

An orthogonal mask mapping of each layer in a physical resource block, ensuring that the time domain is orthogonal and simultaneously in the frequency domain within the physical resource block, the orthogonal mask mapping of each layer at least guarantees each current DMRS resource unit and One or several of the resource elements carrying the DMRS adjacent to the front or the back constitute an orthogonal relationship.

The method according to claim 1, wherein the current DMRS resource unit and the resource unit carrying the DMRS adjacent to the preceding or following are: the bearer DMRS corresponding to the same code division multiplexing (CDM) group. Resource unit.

The method according to claim 1, wherein the OFDM symbol is not

Each port of the CDM group is on a different DMRS resource unit of the same OFDM symbol; the vector form of the corresponding orthogonal mask weights of the respective ports on the DMRS resource unit is different, and is uniformly distributed.

The method according to claim 1, wherein the method further comprises: in the LTE R10 and subsequent evolved versions, the orthogonal mask mapping mode with rank > 2 needs to be compared with the current LTE R9. The rank is 1 to 2 when the orthogonal mask mapping mode is compatible;

The method according to claim 1 or 4, wherein, when different orthogonal mask mapping modes are allocated, the method further comprises: for the ports of two different CDM groups, on a compatible basis, each Ports use different orthogonal mask assignments or choose different orthogonal masks.

6. The method according to claim 5, wherein an orthogonal mask of length 2 is set

In the case of (ab), port { p ₉ , A. } corresponding to (ba); or, when the port in group 1 is mapped on the two adjacent DMRS resource units in the time domain, the vector consisting of orthogonal mask weights is (b Ω), Port ₉ , A. } corresponds b);

Manner 2: When the rank is 5~8, the orthogonal mask mapping with length 4 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: Ports _Ps , _Pn , and } in group 1 are in the time domain. The quantities are respectively (in the case of abc, the ports { p ₉ , _Pl0 , _Pn , _{Ρΐ 4} } correspond to (α deb) , (cdab), (a -b -cd, , (ab -c -b); and the port { p ₉ , p _i0 , p _n , p _i4 } are polled in the same way as port ft ' Pn ';; , · = 0,1,2,3 are row vectors, a, b, c, d represent the matrix formed by Column vector.

A mapping system for demodulating reference symbols, the system comprising: a mapping unit, configured to allocate different DMRS resource units on OFDM symbols on each OFDM symbol mapped with DMRS Orthogonal mask mapping mode; orthogonal mask mapping of each layer in a physical resource block at least ensures that each current DMRS resource unit is orthogonal to one or several of the resource elements of the DMRS adjacent to or behind relationship.

The system according to claim 7, wherein the current DMRS resource unit and the resource unit carrying the DMRS adjacent to the previous or the following are: corresponding to the same CDM group. The resource unit that carries the DMRS.

The system according to claim 7, wherein the mapping unit is further configured to: when the different orthogonal mask mapping modes are uniformly allocated to different DMRS resource units on the OFDM symbol, the same CDM group is configured. Each of the ports is on a different DMRS resource unit of the same OFDM symbol; the vector form of the corresponding orthogonal mask weights of the respective ports on the DMRS resource unit is different, and is uniformly distributed.

The system according to claim 7, wherein the mapping unit is further configured to use the orthogonal mask mapping mode, and it is ensured that in the LTE R10 and subsequent evolved versions, when the rank is >2 The orthogonal mask mapping mode is compatible with the orthogonal mask mapping mode when the rank is 1~2 in the current LTE R9; the compatibility includes: orthogonal mask of port 7 and port 8 when rank>2 The mapping method is the same as the orthogonal mask mapping of port 7 and port 8 when rank is 1~2.

The system according to claim 7 or 10, wherein the mapping unit is further configured to use different orthogonal masks for each port on a compatible basis for ports of two different CDM groups. The code is assigned or a different orthogonal mask is selected.

The system according to claim 11, wherein the mapping unit is further configured to set an orthogonal mask of length 2 to _{w =} ( _a 3⁄4 ); and set an orthogonal mask of length 4

The orthogonal mask mapping manner includes any one of the following modes or a combination of at least one of the following:

Mode 1: When the rank is 3~4, the orthogonal mask mapping with length 2 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: The port {, p, } in group 1 is in the time domain. Two adjacent DMRSs

for

In the case of {ab), the port { p ₉ , A. } corresponds to (ba) ; or, the port in group 1 is at the time The vector consisting of the orthogonal mask weights corresponding to the mapping on the two adjacent DMRS resource elements on the domain is (b Ω), respectively, port ₉ , A. } corresponds b);

Manner 2: When the rank is 5~8, the orthogonal mask mapping with length 4 is used. The orthogonal mask mapping methods corresponding to the two CDM groups include: Ports _Ps , _Pn , and } in group 1 are in the time domain. The quantities are respectively (in the case of abc, the ports { p ₉ , _Pl0 , _Pn , _{Ρΐ 4} } correspond to (α deb), (cdab), (a -b -cd, , (ab -c -b); and the port { p ₉ , p _i0 , p _n , p _i4 } are polled in the same way as port ft ' Pn ';; , · = 0,1,2,3 are row vectors, a, b, c, d represent the matrix formed by Column vector.