CN102904666B - The search volume processing method of enhancing PDCCH based on DM-RS - Google Patents

Abstract

The search volume processing method that the invention provides the enhancing PDCCH based on DM-RS, wherein a kind of method comprises: sort continuously according to the mode of frequency ascending order to strengthening all control channels unit CCE in PDCCH, obtain CCE sequence; To the sequence that interweaves of described CCE sequence, obtain search volume.

Description

Method for processing search space 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 demodulation pilot frequency (DM-RS).

Background

The conventional PDCCH, i.e., PDCCH of Release 8 (abbreviated as R8) or R9 or R10, occupies 1-3 OFDM symbols, and a Control Channel Element (CCE) thereof consists of 9 Resource Element Groups (REGs) and has 36 Resource Elements (REs). In order to support blind detection, the conventional PDCCH introduces a search space, and each UE performs blind detection on control information with aggregation levels of 1, 2, 4, and 8 in the search space. CCEs in the conventional PDCCH are arranged continuously, and scrambling and interleaving processing are required before physical resource mapping so as to ensure that better frequency domain diversity gain is obtained and inter-cell interference randomization is realized.

With the introduction of technologies such as Carrier Aggregation (CA), coordinated multipoint (CoMP), and the like, the capacity of the conventional PDCCH is limited, and increasing the number of OFDM symbols of the PDCCH is a relatively direct solution, but the method has the following problems: there is no backward compatibility. In order to solve this problem, the prior art proposes a common and relatively good method: enhanced PDCCH based on DM-RS. The enhanced PDCCH based on the DM-RS is positioned in a Physical Downlink Shared Channel (PDSCH) region and is multiplexed with the PDSCH in a Frequency Division Multiplexing (FDM) mode.

However, for the enhanced PDCCH based on DM-RS, the search space cannot be designed according to the conventional PDCCH search space, because: the traditional PDCCH covers the full bandwidth, the search space design adopts a CCE continuous sequencing mode, and the frequency domain diversity gain is obtained through interleaving; the enhanced PDCCH acquires the beamforming gain by using the DM-RS, and requires that the occupation of the time-frequency resources by the control information of each UE is consistent with that of the PDSCH, that is, all OFDM symbols in the PDSCH region are continuously occupied and concentrated on a plurality of continuous subcarriers, so that the control information of the UE cannot acquire the frequency domain diversity gain if the design of the conventional PDCCH search space is adopted, and cannot ensure reliability due to the influence of deep fading of the frequency domain channel.

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

Disclosure of Invention

The invention provides a search space processing method of an enhanced PDCCH based on DM-RS (demodulation reference signal), which is used for helping the enhanced PDCCH based on DM-RS to obtain frequency domain diversity gain and improve the capacity of the PDCCH.

The technical scheme provided by the invention comprises the following steps:

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

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.

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

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.

A search space processing method of enhanced PDCCH based on DM-RS is applied to RB pairs carrying the enhanced PDCCH symmetrically distributed at 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.

According to the technical scheme, the search space of the enhanced PDCCH based on the DM-RS can be realized by the three methods, and the enhanced PDCCH based on the DM-RS is helped to obtain frequency domain diversity gain and scheduling gain, so that the reliability is ensured and the capacity of the PDCCH is improved;

furthermore, the method can effectively support the UE to obtain the control information in a blind detection mode, and the control information is consistent with PDCCH blind detection in R8/R9/R10.

Drawings

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

FIG. 2 is a flow chart provided in example 1 of the present invention;

fig. 3 is a flowchart of interleaving arrangement provided in embodiment 1 of the present invention;

FIG. 4 is a flow chart provided in embodiment 2 of the present invention;

fig. 5 is a schematic diagram of CCE segmentation provided in embodiment 3 of the present invention;

fig. 6 is a schematic diagram of CCE segments in RB pairs according to embodiment 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

It can be seen from the background art that, since the enhanced PDCCH obtains the beamforming gain by using the DM-RS, it requires that the occupation of the time-frequency resources by the control information of each UE is consistent with the PDSCH, and therefore, the search space of the enhanced PDCCH based on the DM-RS cannot be designed according to the design method of the conventional PDCCH search space.

The process provided by the present invention is described below by way of three examples:

first, before describing the following three embodiments, the resource information of the enhanced PDCCH is described:

in the present invention, the RB pair carrying the enhanced PDCCH may adopt a static configuration or a semi-static configuration. If the static configuration is adopted, the RB pair carrying the enhanced PDCCH may be continuous, may be discrete, or may be evenly distributed on both sides of the system bandwidth. If semi-static configuration is adopted, the RB pair carrying the enhanced PDCCH may be indicated by the downlink resource allocation type 0/1/2.

In addition, unlike the CCE definition of the conventional PDCCH, in the present invention, the CCE of the enhanced PDCCH may be defined by:

number of OFDM symbols of PDSCH per contiguous subcarrier.

Wherein 12 is needed to be coveredInteger division, parameterIs a cell-specific parameter (cell-specific), is semi-statically configured by the eNB through RRC. Fig. 1 shows CCEs of an enhanced PDCCH provided by the present invention.

Each RB pair in the enhanced PDCCH containsCCE (c)) And a one-to-one correspondence relationship needs to be established between each CCE and a DM-RS port, that is, the ith CCE in each RB pair corresponds to a DM-RS port 7+ i, that is, demodulation of information on the ith CCE is based on the DM-RS port 7+ i, where

Preferably, if the CCEs corresponding to each port in a certain 1 DM-RS group respectively use precoding vectorsWherein the precoding vectors are column vectors, and the DM-RS group uses N_DMRSA plurality of ports are arranged on the base plate,is the port number, N, of each DM-RS in the DM-RS group_DMRSFor the number of ports used in the DM-RS group, then the precoding vectors are concatenated into precoding momentsArraying: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 this embodiment 1, a search space is designed based on CCE interleaving ordering, and specifically includes the procedure shown in fig. 2:

step 201, continuously sequencing all CCEs in the enhanced PDCCH in a frequency ascending manner to obtain a CCE sequence.

Step 202, performing interleaving sequencing on the CCE sequences to obtain a search space.

The number of all CCEs of the enhanced PDCCH is N_CCEThe flow shown in fig. 2 is described for example:

first, for all N in the enhanced PDCCH_CCEThe CCEs are ordered, wherein all N in the enhanced PDCCH is ordered according to the conventional PDCCH ordering mode_CCEThe CCEs are continuously sequenced, namely all CCEs are sequenced in a frequency ascending manner to obtain a CCE sequence, and the serial numbers of the CCEs in the CCE sequence are 0, 1_CCE-1。

And then, interleaving and sequencing the obtained CCE sequences, namely, interleaving 2 CCEs with adjacent serial numbers to disperse the CCEs on a frequency domain, wherein the interleaving can be realized by block interleaving. The specific implementation method comprises the flow shown in fig. 3:

step 301, adjusting the CCE sequences of the consecutive ordering to obtain an adjusted CCE sequence.

Assume that the number of RB pairs in the enhanced PDCCH is K_RBThen, for a CCE with a sequence number N in the CCE sequence, N takes a value of 0, 1_CCE-1, adjusted serial number ofn', is obtained in particular by the following formula:

wherein,the number of CCEs included in an RB pair.

Step 302, sending the adjusted CCE sequences to a block interleaver with a column number G according to a row-by-row writing principle, and using the obtained sequence numbers of all CCEs as the sequence numbers of all CCEs after interleaving and sorting according to a column-by-column reading principle.

So far, the interleaving ordering of CCE sequences can be realized by fig. 3.

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

After the search space design is completed, 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. The method specifically comprises the following steps:

search spaces corresponding to aggregation level LThe CCE number corresponding to the mth PDCCH candidate is:

wherein, L takes the values of 1, 2, 4 and 8, and Y_kGenerated by the Hashing function, M' ═ M + M^(L)·n_CI，n_CIIs a CIF value, M^(L)I is the number of PDCCH candidates in aggregation level L, i is 0, 1.

The description of embodiment 1 is completed so far.

Example 2:

unlike embodiment 1, in embodiment 2, respective search spaces are defined for different aggregation levels, and the method specifically includes the following steps shown in fig. 4:

step 401, grouping all CCEs in the enhanced PDCCH in units of L for an aggregation level L, where L takes values of 1, 2, 4, and 8.

And step 402, interleaving and sequencing the serial numbers of all CCE groups to obtain a search space.

In this step 402, the specific operation of performing interleaving and sorting on the sequence numbers of all CCE groups is as follows: and sending the serial numbers of all CCE groups into a block interleaver with the column number as a set value G according to a line-by-line writing principle, and taking the obtained serial numbers of all CCE groups as the serial numbers of all the CCE groups after interleaving and sequencing according to a line-by-line reading principle.

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

then, the group number is sorted according to the specific operation of interleaving sorting in step 402And (6) sorting. After the sorting is completed, the design of the search space is performed according to the design principle of the R8 search space.

And after the search space design is finished, determining the corresponding CCE group serial number according to the aggregation level corresponding to the search space and the serial number of the candidate PDCCH aiming at each search space. The method specifically comprises the following steps:

search spaces corresponding to aggregation level LIn (1), the CCE group number corresponding to the mth PDCCH candidate is

$(Y_k+m^{\′})\mathrm{mod}{A}_{\mathrm{total}}^{\left(L\right)}.$

Wherein $m^{\′}=m+M^{\left(L\right)}\·n_{\mathrm{CI}}.$

The description of embodiment 2 is completed so far.

Example 3:

in the above embodiments 1 and 2, the distribution of RB pairs carrying enhanced PDCCH is not limited, and it does not require any processing on the above-defined CCEs.

In this embodiment 3, the RB pairs carrying the enhanced PDCCH are symmetrically distributed on two sides of the system bandwidth, and the search space is designed based on a frequency hopping scheme. In this scheme, the CCE needs to be further processed: i.e. dividing the CCE into 2 CCE segments (CCEsegment) as shown in detail in fig. 5. Based on this, when CCE is defined as aboveMust be divided by 2.

In the mth CCE, the CCE is divided into 2 CCE segments with resource positions (n)_PRBAnd i) is:

wherein n is_PRBDenotes an RB number, i denotes the number of CCE segments within an RB,for the number of RB pairs in the downlink system bandwidth,is the number of CCE segments contained in one RB pair. Fig. 6 illustrates CCE segments by way of example where each RB pair contains 4 CCE segments.

Because each CCE can simultaneously occupy the frequency bands on two sides and the resource positions are in one-to-one correspondence, namely 2 CCE segments belonging to 1 CCE are symmetrically placed on the 2 side of the system bandwidth, a search space only needs to be designed for a certain side frequency band. When designing the search space, the CCE segments of the certain side band may be ordered. The ordering rule may be a continuous manner, or may adopt the above-mentioned interleaving ordering manner, and the present invention is not particularly limited.

In this embodiment, the DM-RS ports should establish a one-to-one correspondence with CCE segments. If each RB pair in the enhanced PDCCH containsA number of CCE segments () Then, thenThe ith CCE segment in each RB pair corresponds to DM-RS port 7+ i, that is, the demodulation of the information on the ith CCE segment is based on DM-RS port 7+ i, where

In this embodiment 3, there is no particular requirement on the search space design, and the search space design may consider a design scheme of R8CCE rank ordering or other schemes, and the present invention is not limited thereto. In addition, after the search space design is completed, for each search space, the corresponding CCE segment is determined according to the aggregation level corresponding to the search space and the number of the PDCCH candidate, and specifically, the CCE or CCE group number may be determined in embodiment one or embodiment 2.

It can be seen that this embodiment 3 can be regarded as the re-enhancement of the first 2 embodiments, except that the CCEs are subdivided and 2 segments are symmetrically placed on both sides of the system bandwidth. This embodiment 3 is not only suitable for enhancing the first 2 embodiments, but also suitable for enhancing the design scheme of the search space with continuous CCE ordering.

However, it should be noted that if the scheme is adopted for re-enhancement, the CCE ordering and the design of the search space only need to be directed to CCE segments within one side of the system bandwidth.

The description of embodiment 3 is completed so far.

According to the technical scheme, the search space of the enhanced PDCCH based on the DM-RS can be realized by the three methods, and the enhanced PDCCH based on the DM-RS is helped to obtain frequency domain diversity gain and scheduling gain, so that the reliability is ensured and the capacity of the PDCCH is improved;

furthermore, the method can effectively support the UE to obtain the control information in a blind detection mode, and the control information is consistent with PDCCH blind detection in R8/R9/R10.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (3)

1. 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.

2. The method according to claim 1, 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.

3. The method of claim 1, wherein the CCEs of enhanced PDCCH are defined by:number of OFDM symbols of PDSCH of continuous subcarriers, 12 of which areInteger division, parameterFor cell-specific parameters, semi-static configuration by the eNB through RRC.