CN102904666A - Search Space Processing Method of Enhanced PDCCH Based on DM-RS - Google Patents

Abstract

The invention provides a DM-RS (demodulation reference signal) based method for processing a search space of an enhanced PDCCH (physical downlink control channel). The DM-RS based processing method includes the steps of continuously sequencing all control channel elements (CCE) in the enhanced PDCCH in a frequency-ascending sequence to obtain CCE sequences, and interleaving and sequencing the CCE sequences to obtain the search space.

Description

Search Space Processing Method of Enhanced PDCCH Based on DM-RS

technical field

The invention relates to the technical field of wireless communication, in particular to a search space processing method of an enhanced downlink control channel (PDCCH) based on a pilot frequency for demodulation (DM-RS).

Background technique

The traditional PDCCH is the PDCCH of version 8 (referred to as R8) or R9 or R10, occupying 1 to 3 OFDM symbols, and its control channel element (CCE) consists of 9 resource element groups (REG), a total of 36 resource elements ( RE). In order to support blind detection, traditional PDCCH introduces a search space, and each UE completes blind detection of control information with aggregation levels 1, 2, 4, and 8 in the search space. The CCEs in the traditional PDCCH are arranged continuously, and scrambling and interleaving processing are required before physical resource mapping to ensure better frequency domain diversity gain and achieve inter-cell interference randomization.

With the introduction of carrier aggregation (CA), coordinated multi-point (CoMP) and other technologies, the capacity of traditional PDCCH is limited, and increasing the number of OFDM symbols of PDCCH is a relatively direct solution, but this method has the following problems: it does not have backward compatibility. In order to solve this problem, the prior art proposes a commonly used and relatively better method: DM-RS-based enhanced PDCCH. The DM-RS-based enhanced PDCCH is located in a physical downlink shared channel (PDSCH) region, and is multiplexed with the PDSCH in a frequency division multiplexing (FDM) manner.

However, for the enhanced PDCCH based on DM-RS, its search space cannot be designed according to the traditional PDCCH search space. The reason is that the traditional PDCCH covers the full bandwidth, and its search space design adopts the CCE sequential ordering method to obtain frequency domain diversity through interleaving. gain; and the enhanced PDCCH uses DM-RS to obtain beamforming gain, which requires that the control information of each UE occupy the time-frequency resources to be consistent with the PDSCH, that is, continuously occupy all OFDM symbols in the PDSCH area and concentrate on several consecutive In this way, if the traditional PDCCH search space design is adopted, the UE's control information cannot obtain frequency domain diversity gain, and is easily affected by deep channel fading in the frequency domain, so reliability cannot be guaranteed.

Therefore, the design of a DM-RS-based enhanced PDCCH search space is a technical problem to be solved urgently.

Contents of the invention

The invention provides a search space processing method of the DM-RS-based enhanced PDCCH to help the DM-RS-based enhanced PDCCH obtain frequency domain diversity gain and improve the capacity of the PDCCH.

The technical solutions provided by the invention include:

A method for processing a search space of an enhanced PDCCH based on DM-RS, the method comprising:

Continuously sort all control channel element CCEs in the enhanced PDCCH in ascending order of frequency to obtain a CCE sequence;

Perform interleaving and sorting on the CCE sequences to obtain a search space.

A method for processing a search space of an enhanced PDCCH based on DM-RS, the method comprising:

For the aggregation level L, group all CCEs in the enhanced PDCCH in units of L, where the values of L are 1, 2, 4, and 8;

The sequence numbers of all CCE groups are interleaved and sorted to obtain the search space.

A DM-RS-based enhanced PDCCH search space processing method, the method is applied to the symmetrical distribution of RB pairs carrying the enhanced PDCCH on both sides of the system bandwidth, including:

Divide the CCE in the enhanced PDCCH into two CCE segments;

Sort the CCE fragments on one side of the system bandwidth to obtain the search space.

It can be seen from the above technical solutions that in the present invention, the search space of the enhanced PDCCH based on DM-RS can be realized through the above three methods, and the enhanced PDCCH based on DM-RS can be helped to obtain frequency domain diversity gain and scheduling gain, thereby ensuring reliable performance and improve the capacity of PDCCH;

Furthermore, the present invention can effectively support UE to obtain control information through blind detection, which is consistent with PDCCH blind detection in R8/R9/R10.

Description of drawings

Fig. 1 shows the CCE schematic diagram of the enhanced PDCCH provided by the present invention;

FIG. 2 is a flowchart provided by Embodiment 1 of the present invention;

FIG. 3 is a flow chart of interleaving and sorting provided by Embodiment 1 of the present invention;

FIG. 4 is a flowchart provided by Embodiment 2 of the present invention;

FIG. 5 is a schematic diagram of CCE division of CCE segments provided by Embodiment 3 of the present invention;

FIG. 6 is a schematic diagram of CCE fragments in an RB pair provided by Embodiment 3 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

It can be seen from the background technology that because the enhanced PDCCH uses DM-RS to obtain beamforming gain, it requires that the control information of each UE occupy time-frequency resources consistent with the PDSCH. Therefore, the search for enhanced PDCCH based on DM-RS The space cannot be designed according to the traditional PDCCH search space design method. The present invention provides a design method for the DM-RS-based enhanced PDCCH search space to help the DM-RS-based enhanced PDCCH obtain frequency domain diversity gain and scheduling gain, thereby ensuring Reliability and improve the capacity of PDCCH.

The method provided by the invention is described below by three embodiments:

First, before describing the following three embodiments, first describe the resource information of the enhanced PDCCH:

In the present invention, the RB pair carrying the enhanced PDCCH can adopt static configuration or semi-static configuration. Wherein, if static configuration is adopted, the RB pairs carrying the enhanced PDCCH may be continuous, discrete, or evenly distributed on both sides of the system bandwidth. If the semi-static configuration is adopted, the RB pair that bears the enhanced PDCCH can be indicated through the downlink resource allocation type 0/1/2.

In addition, different from the CCE definition of the traditional PDCCH, in the present invention, the CCE of the enhanced PDCCH can be defined in the following manner:

个连续子载波*PDSCH的OFDM符号数。

The number of OFDM symbols of consecutive subcarriers*PDSCH.

整除，参数

为小区专用参数(cell-specific)，由eNB通过RRC半静态配置。图1示出了本发明提供的增强PDCCH的CCE。12 of them shall be

divisible, parameter

It is a cell-specific parameter, which is semi-statically configured by the eNB through RRC. Fig. 1 shows the CCE of the enhanced PDCCH provided by the present invention.

个CCE(

)，而每个CCE与DM-RS端口之间需要建立一一对应的关系，即每个RB对中的第i个CCE与DM-RS端口7+i对应，也就是说，第i个CCE上信息的解调基于DM-RS端口7+i，其中

Each RB pair in the enhanced PDCCH contains

CCE (

), and a one-to-one correspondence needs to be established between each CCE and DM-RS port, that is, the i-th CCE in each RB pair corresponds to DM-RS port 7+i, that is, the i-th CCE The demodulation of the above information is based on DM-RS port 7+i, where

其中预编码矢量均为列矢量，该DM-RS组使用到N_DMRS个端口，为该DM-RS组中的各DM-RS的端口号，N_DMRS为该DM-RS组中使用到的端口数，那么将这些预编码矢量级联为预编码矩阵：

此预编码矩阵用于该DM-RS组的预编码处理。Preferably, if the CCEs corresponding to each port in a DM-RS group use precoding vectors respectively

The precoding vectors are all column vectors, and the DM-RS group uses N _DMRS ports, For the port number of each DM-RS in the DM-RS group, N _DMRS is the number of ports used in the DM-RS group, then these precoding vectors are concatenated into a precoding matrix:

This precoding matrix is used for precoding processing of the DM-RS group.

Based on the above description, three embodiments provided by the present invention are described below:

Example 1:

In Embodiment 1, the search space is designed based on CCE interleaving sorting, which specifically includes the process shown in Figure 2:

In step 201, all CCEs in the enhanced PDCCH are sequentially sorted in ascending order of frequency to obtain a CCE sequence.

Step 202, performing interleaving and sorting on the CCE sequence to obtain a search space.

Taking the number of all CCEs of the enhanced PDCCH as N _CCEs as an example to describe the process shown in Figure 2:

First, all the N _CCE CCEs in the enhanced PDCCH are sorted. Here, all the N _CCE CCEs in the enhanced PDCCH are sequentially sorted according to the traditional PDCCH sorting method, that is, all the CCEs are sorted in ascending order of frequency to obtain the CCE sequence. The sequence numbers of the CCEs in the CCE sequence are 0, 1, . . . , N _CCE -1.

Afterwards, perform interleaving and sorting on the obtained CCE sequences, that is, perform interleaving processing on two CCEs with adjacent sequence numbers to disperse them in the frequency domain, which can be realized through block interleaving. The specific implementation method includes the process shown in Figure 3:

Step 301: Adjust the continuously sorted CCE sequences to obtain the adjusted CCE sequences.

Assuming that the number of RB pairs in the enhanced PDCCH is K _RB , then for a CCE with sequence number n in the CCE sequence, n takes the value of 0, 1, ..., N _CCE -1, and its adjusted sequence number is n′, Specifically, it is obtained by the following formula:

为RB对包含的CCE的个数。in,

is the number of CCEs included in the RB pair.

Step 302, send the adjusted CCE sequence into the block interleaver whose column number is G according to the principle of row-by-row writing, and use the sequence numbers of all CCEs obtained as the sequence numbers of all CCEs after interleaving and sorting according to the principle of column-by-column reading. serial number.

So far, the interleaving and sorting of the CCE sequences can be realized through FIG. 3 .

After the CCE interleaving and sorting is completed, the search space is designed according to the design principle of the R8 search space.

After the search space design is completed, for a search space, the corresponding CCE sequence number is determined according to the aggregation level and the number of candidate PDCCHs corresponding to the search space. Specifically:

The search space corresponding to the aggregation level L The CCE sequence number corresponding to the mth PDCCH candidate is:

Among them, the values of L are 1, 2, 4, 8, Y _k is generated by the Hashing function, m′=m+M ^(L) n _CI , n _CI is the CIF value, and M ^(L) is the candidate under the aggregation level L The number of PDCCHs, i=0, 1, . . . , L-1.

So far, the description of Embodiment 1 is completed.

Example 2:

This embodiment 2 is different from embodiment 1. In this embodiment 2, it defines its own search spaces for different aggregation levels, specifically including the process shown in Figure 4:

Step 401 , for the aggregation level L, group all CCEs in the enhanced PDCCH in units of L, where the value of L is 1, 2, 4, or 8.

Step 402, interleaving and sorting the sequence numbers of all CCE groups to obtain a search space.

In this step 402, the specific operation of interleaving and sorting the sequence numbers of all CCE groups is: according to the principle of row-by-row writing, the sequence numbers of all CCE groups are sent to the block interleaver whose column number is a set value G, The principle of reading is to use the obtained sequence numbers of all CCE groups as the sequence numbers of all CCE groups after interleaving and sorting.

It can be seen that in this embodiment 2, for the aggregation level L, all CCEs are grouped in units of L first, and each CCE group corresponds to a PDCCH candidate, and is composed of consecutive L CCEs, and the total number of obtained CCE groups is :

进行排序。在完成排序后，根据R8搜索空间的设计原理进行搜索空间的设计。Then, according to the specific operation of the interleaving and sorting described in step 402, the group sequence numbers are

Sort. After the sorting is completed, the search space is designed according to the design principle of the R8 search space.

After the search space design is completed, for each search space, the corresponding CCE group sequence number is determined according to the aggregation level corresponding to the search space and the number of candidate PDCCHs. Specifically:

中，第m个PDCCH候选对应的CCE组序号为The search space corresponding to the aggregation level L

, the CCE group number corresponding to the mth PDCCH candidate is

$<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; mod</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; total</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; .</span>$

in $m^{\&prime;}=m+m^{\left(L\right)}\&CenterDot;{\mathrm{no}}_{\mathrm{CI}}.$

So far, the description of Embodiment 2 is completed.

Example 3:

In the above-mentioned embodiment 1 and embodiment 2, the distribution of the RB pairs carrying the enhanced PDCCH is not limited, and it does not need to perform any processing on the CCEs defined above.

须被2整除。However, in Embodiment 3, it is applied to a scenario where the RB pairs carrying the enhanced PDCCH are symmetrically distributed on both sides of the system bandwidth, and the search space is mainly designed based on frequency hopping. In this solution, further processing needs to be performed on the CCE: that is, the CCE is divided into two CCE segments (CCE segment), as shown in FIG. 5 . Based on this, when defining CCE above, the

must be divisible by 2.

In the mth CCE, the resource positions (n _PRB , i) of the two CCE segments obtained by dividing the CCE are:

为下行系统带宽中RB对的数量，

为一个RB对中包含的CCE片段的数量。图6以每个RB对包含4个CCE片段为例示出了CCE片段。Among them, n _PRB represents the RB number, i represents the number of the CCE segment in the RB,

is the number of RB pairs in the downlink system bandwidth,

is the number of CCE segments included in one RB pair. FIG. 6 shows CCE segments by taking each RB pair as an example containing 4 CCE segments.

Because in the present invention, because each CCE can occupy frequency bands on both sides at the same time and the resource position corresponds one by one, namely the 2 CCE fragments belonging to 1 CCE are symmetrically placed on the system bandwidth 2 side, so only need to a certain side frequency band Just design the search space. When designing the search space, the CCE segments of the frequency band on one side can be sorted. The sorting rules may be continuous, or the above-mentioned interleaved sorting mode, which is not specifically limited in the present invention.

个CCE片段()，那么每个RB对中的第i个CCE片段与DM-RS端口7+i对应，也就是说，第i个CCE片段上信息的解调基于DM-RS端口7+i，其中

In this embodiment, a one-to-one correspondence should be established between DM-RS ports and CCE segments. If each RB pair in the enhanced PDCCH contains

CCE fragments ( ), then the i-th CCE segment in each RB pair corresponds to DM-RS port 7+i, that is, the demodulation of information on the i-th CCE segment is based on DM-RS port 7+i, where

In Embodiment 3, there is no special requirement for the design of the search space, and the design of the search space may consider the design scheme of R8CCE sequential ordering, or other schemes, which are not limited by the present invention. In addition, after completing the design of the search space, for each search space, determine the corresponding CCE segment according to the aggregation level corresponding to the search space and the number of the candidate PDCCH. Specifically, the determination of the CCE or CCE group in Embodiment 1 or Embodiment 2 serial number method.

It can be seen that Embodiment 3 of this embodiment can be regarded as a re-enhancement of the previous two embodiments, only that the CCEs are re-divided and the two segments are symmetrically placed on both sides of the system bandwidth. Embodiment 3 is not only suitable for enhancing the first two embodiments, but also suitable for enhancing the search space design scheme of CCE continuous ranking.

However, it should be noted that if this solution is adopted for re-enhancement, the design of CCE sorting and search space only needs to target the CCE segments within one side of the system bandwidth.

So far, the description of Embodiment 3 is completed.

It can be seen from the above technical solutions that in the present invention, the search space of the enhanced PDCCH based on DM-RS can be realized through the above three methods, and the enhanced PDCCH based on DM-RS can be helped to obtain frequency domain diversity gain and scheduling gain, thereby ensuring reliable performance and improve the capacity of PDCCH;

Furthermore, the present invention can effectively support UE to obtain control information through blind detection, which is consistent with PDCCH blind detection in R8/R9/R10.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (12)

1. A method for processing a search space of a DM-RS (demodulation reference Signal) based enhanced PDCCH (physical Downlink control channel), which is characterized by comprising the following steps:

continuously sequencing all Control Channel Elements (CCE) in the enhanced PDCCH in a frequency ascending manner to obtain a CCE sequence;

and performing interleaving sequencing on the CCE sequences to obtain a search space.

2. The method of claim 1, wherein the interleaving ordering of CCE sequences comprises:

adjusting a CCE sequence;

and sending the adjusted serial numbers of all CCEs into a block interleaver with the column number being a set value G according to a line-by-line writing principle, and taking the obtained serial numbers of all CCEs as the serial numbers of all CCEs after interleaving and sequencing according to a line-by-line reading principle.

3. The method of claim 2, wherein the CCE sequences are adjusted according to the following formula:

wherein n is the CCE serial number, n' is the adjusted CCE serial number,is the number of CCEs contained in an RB pair, K_RBIs the total number of RB pairs.

4. The method of claim 1, further comprising:

and aiming at a search space, determining the corresponding CCE serial number according to the aggregation level corresponding to the search space and the serial number of the candidate PDCCH.

5. The method according to claim 4, wherein the determining the corresponding CCE serial numbers according to the aggregation levels and the candidate PDCCH numbers corresponding to the search spaces comprises:

will be determined by the following formula:

the calculated value is determined as the corresponding CCE serial number; wherein, L is polymerization grade and takes the values of 1, 2, 4 and 8; y is_kGenerated by the Hashing function, M' ═ M + M^(L)·n_CI，n_CIIndicating CIF value for component carrier, m is number of candidate PDCCH，M^(L)Is the number of PDCCH candidates under aggregation level L, N_CCETo enhance the total number of CCEs in the PDCCH, i is 0, 1.

6. A method for processing a search space of a DM-RS (demodulation reference Signal) based enhanced PDCCH (physical Downlink control channel), which is characterized by comprising the following steps:

grouping all CCEs in the enhanced PDCCH by taking L as a unit aiming at an aggregation level L, wherein the value of L is 1, 2, 4 and 8;

and carrying out interleaving sequencing on the serial numbers of all CCE groups to obtain a search space.

7. The method of claim 6, further comprising:

and aiming at each search space, determining the corresponding CCE group number according to the aggregation level corresponding to the search space and the number of the candidate PDCCH.

8. The method according to claim 7, wherein the determining the corresponding CCE group number according to the aggregation level and the candidate PDCCH number corresponding to the search space comprises:

will be determined by the following formula:

the calculated value is determined as the corresponding CCE group serial number;

wherein, Y_kGenerated by the Hashing function, M' ═ M + M^(L)·n_CIM is the number of the PDCCH candidate, M^(L)The number of candidate PDCCHs under the aggregation level corresponding to the search space, n_CIThe value of the CIF is the value of the CIF,

the total number of CCE groups into which all CCEs in the enhanced PDCCH are divided for the aggregation level corresponding to the search space.

9. The method according to claim 1 or 6, characterized in thatCharacterized in that the CCE of the enhanced PDCCH is defined by:number of OFDM symbols of PDSCH of continuous subcarriers, 12 of which are

Integer division, parameter

For cell-specific parameters, semi-static configuration by the eNB through RRC.

10. The method according to claim 1 or 6, wherein the CCEs in the enhanced PDCCH and the DM-RS ports have a one-to-one correspondence relationship, specifically: the ith CCE corresponds to the DM-RS port 7+ i one by one.

11. A method for processing a search space of an enhanced PDCCH based on DM-RS is characterized in that RB pairs for bearing the enhanced PDCCH are symmetrically distributed on two sides of a system bandwidth, and comprises the following steps:

dividing CCE in the enhanced PDCCH into two CCE fragments;

and sequencing CCE segments on one side of the system bandwidth to obtain a search space.

12. The method according to claim 11, wherein the CCE segment has a one-to-one correspondence with a DM-RS port, specifically: the ith CCE segment corresponds to the DM-RS port 7+ i one by one.

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