CN101635950A - Method and device for determining positions of cell reference signals - Google Patents

Abstract

The invention provides a method and a device for determining positions of cell reference signals. The method comprises the following steps: selecting a plurality of coordinate cell positions for transmitting CSI-RS of the coordinate cells from the positions for transmitting channel state information reference signals (CSI-RS) in difference cells; and determining the positions of CSI-RS of the coordinate cells according to marks of the coordinate cells. By using the method, target UE defines a plurality of cell positions transmitting CSI-RS, thereby achieving the goal of using a base station for transmitting data by measuring channel state information of a plurality of cells and reporting the information to the base station so as to ensure the application of multi-point coordinate transmission and reception (CoMP) technique to improve the overall performance of the system.

Description

Method and device for determining position of cell reference signal

Technical Field

The present invention relates to Long Term Evolution (LTE) technologies, and in particular, to a method and an apparatus for determining a cell reference signal position.

Background

Orthogonal Frequency Division Multiplexing (OFDM) technology is essentially a multi-carrier modulation communication technology, and OFDM technology is one of the core technologies in fourth generation mobile communication. In order to overcome the frequency selective fading characteristic of the multipath channel of the OFDM in the frequency domain, the channel is divided into a plurality of sub-channels in the frequency domain, the frequency spectrum characteristic of each sub-channel is approximately flat, and the sub-channels of the OFDM are orthogonal to each other. Therefore, the frequency spectrums of the sub-channels are allowed to overlap with each other, so that the frequency spectrum resources can be utilized to a large extent.

The Multiple Input Multiple Output (MIMO) technology can increase system capacity, improve transmission performance, and can be well integrated with other physical layer technologies, thus becoming a key technology of B3G and 4G mobile communication systems. However, when the channel correlation is strong, the diversity gain and the multiplexing gain due to the multipath channel are greatly reduced, which causes a significant decrease in the performance of the MIMO system. In order to eliminate the influence of channel correlation, the MIMO precoding method is used as an efficient MIMO multiplexing mode, and the MIMO is channelized into a plurality of independent virtual channels through precoding processing at a transmitting end and a receiving end, so that the stable performance of the MIMO system under various environments is ensured.

The LTE system is an important project for the third generation partnership. Fig. 1 is a schematic diagram of frame structures of a Frequency Division Duplex (FDD) mode and a Time Division Duplex (TDD) mode of an LTE system, where as shown in fig. 1, in the frame structure of the FDD mode, a radio frame (radio frame) of 10ms is composed of twenty slots (slots) with a length of 0.5ms and a number of 0-19, and slots 2i and 2i +1 are composed of subframes (subframes) i with a length of 1 ms; in the frame structure of the TDD mode, a 10ms radio frame (radio frame) is composed of two half-frames (half frames) with a length of 5ms, and one half-frame includes 5 subframes (subframe) with a length of 1 ms. Subframe i is defined as 2 slots 2i and 2i +1 of length 0.5 ms. When the system adopts the conventional cyclic prefix, one time slot comprises uplink/downlink symbols with the length of 7; when the system employs an extended cyclic prefix, one slot contains up/down symbols of 6 lengths. Fig. 2 is a schematic structural diagram of a physical Resource Block when the system bandwidth of the LTE system is 5MHz, and as shown in fig. 2, one Resource Element (RE) is one subcarrier in one OFDM symbol, and one downlink Resource Block (RB) is composed of 12 consecutive subcarriers and 7 consecutive (6 when a cyclic prefix is extended) OFDM symbols, and is 180kHz in a frequency domain and a time length of one general slot in a time domain, and when Resource allocation is performed, Resource blocks are allocated as a basic unit.

The LTE system supports MIMO application of 4 antennas, and the corresponding antenna port #0, antenna port #1, antenna port #2, and antenna port #3 all adopt a full-bandwidth Cell-specific reference signal (CRS) mode. Fig. 3a is a schematic diagram of positions of cell common reference signals in physical resource blocks in an LTE system when a cyclic prefix is a normal cyclic prefix, where the positions of the cell common reference signals in the physical resource blocks are shown in fig. 3 a; fig. 3b is a schematic diagram of positions of cell common reference signals in a physical resource block when a cyclic prefix is an extended cyclic prefix in an LTE system, where the positions of the cell common reference signals in the physical resource block are shown in fig. 3b, and in fig. 3a and 3b, an abscissa represents a time domain and an ordinate represents a frequency domain. In addition, there is also a user-specific reference signal (UE-specific reference signals) that is transmitted only at a time-frequency domain position where a user-specific Physical shared channel (PDSCH) is located. Wherein the cell common reference signal function includes downlink channel quality measurement and downlink channel estimation (demodulation).

LTE Advanced (LTE-Advanced, Further Advances for E-UTRA) is an evolved version of LTERElease-8. Unless 3GPP TR 25.913 is met or exceeded: all relevant Requirements of "Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN)" are met or exceeded by IMT-Advanced Requirements set forth by ITU-R. Wherein, the requirement of backward compatibility with LTE Release-8 refers to that: the terminal of LTE Release-8 can work in an LTE-Advanced network; the terminal of LTE-Advanced can work in the network of LTE Release-8.

In addition, LTE-Advanced should be able to operate with different size spectrum configurations, including wider spectrum configurations (e.g., 100MHz contiguous spectrum resources) than LTE Release-8, to achieve higher performance and target peak rates. Since the LTE-Advanced network needs to be able to access LTE users, its operating band needs to cover the current LTE band, and there is no allocable continuous 100MHz spectrum bandwidth in this band. Therefore, one direct technique that LTE-Advanced needs to solve is to aggregate several continuous Component carrier frequencies (Component carriers), i.e., frequency spectrums, distributed over different frequency bands to form a 100MHz bandwidth that LTE-Advanced can use. I.e. for the aggregated spectrum, is divided into n component carrier frequencies, the spectrum within each component carrier frequency being continuous.

The LTE-Advanced downlink can support the application of 8 antennas at most; furthermore, as an application supporting 8 antennas and technologies such as Coordinated multiple point transmission and reception (CoMP), dual-stream (Beamforming), and the like, LTE-Advanced defines a downlink reference signal for LTE-Advanced operation as two types of reference signals, using a basic design framework (Way forward) of LTE-Advanced downlink reference signals: reference signals for PDSCH demodulation and reference signals for Channel State Information (CSI) generation.

The CoMP technology is substantially an extension of the multi-antenna technology, and the base stations of multiple cells cooperate to send data to a target User Equipment (UE), so that the target UE needs to know the locations of reference signals (CSI-RS) for sending CSI by the multiple cells, and thus the UE can measure and report channel state information of the multiple cells to the base station, so that the base station is used for data sending, thereby implementing the CoMP technology.

At present, no scheme for determining the positions of CSI-RS of a plurality of cells exists, so the invention provides a method for determining the positions of reference signals of the cells, thereby ensuring the application of a CoMP technology and achieving the aim of improving the overall performance of a system;

disclosure of Invention

In view of the above, the main objective of the present invention is to provide a method for determining a cell reference signal position, which can ensure the application of CoMP technology and improve the overall performance goal of the system.

Another objective of the present invention is to provide an apparatus for determining a cell reference signal position, which can ensure the application of CoMP technology and improve the overall performance target of the system.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a method of determining a cell reference signal location, the method comprising:

and determining the position of a reference signal CSI-RS of the channel state information of the cell, and measuring and reporting the channel state information of a plurality of cells to the base station by the user equipment UE according to the position of the CSI-RS.

The cell is a cooperative cell; the determining the location of the reference signal CSI-RS of the channel state information of the cell includes:

selecting a plurality of positions of a cooperative cell for transmitting CSI-RS of each cooperative cell from positions of reference signals CSI-RS which can be used for transmitting channel state information of different cells;

and determining the position of the CSI-RS of each cooperative cell according to the identification of each cooperative cell.

The position sequence number of the CSI-RS which can be currently used for sending different cells is k₁，k₂，…，k_nSelecting a plurality of locations of a cooperating cell for transmitting each cooperating cell CSI-RS comprises:

the m positions for transmitting the CSI-RS of the m cells are k_h，k_h+1，…，k_h+m-1(ii) a The m positions are consecutive;

where m denotes each cooperative cell, and h is a fixed value or is preset.

When h is a fixed value, the value of h is 0 or n-m;

where n represents the number of locations currently available for transmitting CSI-RS of different cells.

And when the h is preset, the base station informs the target UE of the value of the h through signaling.

The selecting a plurality of positions of the cooperative cells for transmitting the CSI-RS of each cooperative cell comprises:

selecting a combination of m positions from all n positions for numbering, wherein any m positions are uniquely corresponding to a numbering index r, and each numbering index r is uniquely corresponding to the m positions;

according to the positions of the CSI-RSs of the m cells, the base station selects a number index to send to the target UE;

the target UE obtains m pieces of position information according to the received number index r and the corresponding relation between the number index r and the position;

wherein n represents the number of positions currently available for transmitting CSI-RSs of different cells; m denotes each cooperative cell.

The position sequence number of the CSI-RS which can be currently used for sending different cells is k₁，k₂，…，k_nThe selected m positions areWherein, 1 is less than or equal to s_k≤n，s_k＜s_k+1；

The number index <math> <mrow> <mi>r</mi> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>m</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>n</mi> <mo>-</mo> <msub> <mi>s</mi> <mi>k</mi> </msub> </mtd> </mtr> <mtr> <mtd> <mi>m</mi> <mo>-</mo> <mi>k</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </math> $r=0,...,\left(\begin{array}{c}n\\ m\end{array}\right)-1,$ Wherein the definition of the extended binomial coefficients: <math> <mrow> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mfenced open='(' close=')'> <mtable> <mtr> <mtd> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> </mtd> <mtd> <mi>x</mi> <mo>&GreaterEqual;</mo> <mi>y</mi> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mi>x</mi> <mo>&lt;</mo> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </math> $\left(\begin{array}{c}x\\ y\end{array}\right)$ representing the combined number C of y of the x different values_x ^y。

And the number indexes r of the m positions of the m cell CSI-RSs are transmitted to the target UE by the base station through signaling.

The m positions of the m cell CSI-RS are transmitted through m signaling, and each signaling represents the CSI-RS position of one cell.

Determining the position of each CSI-RS of the cooperative cell comprises: determining the position of a cell CSI-RS (channel state information-reference signal) according to the sequence of m cell identifiers sent by a base station;

or sequencing the m cells according to the size of the cell identifier, and determining the position of the CSI-RS of the cell according to the sequenced position.

The determining the location of the cell CSI-RS according to the sequence of the m cell identifiers sent by the base station specifically includes:

and when the order of sending the cell ID in m cell identifiers is g, the position of the CSI-RS corresponding to the cell is the g-th position in the m positions.

Sorting the m cells according to the size of the cell identifier, and determining the positions of the cell CSI-RS according to the sorted positions specifically comprises:

and when the position of the certain cell ID in the sequence is g, the position of the CSI-RS corresponding to the cell is the g-th position in the m positions.

Determining the position of each CSI-RS of each cooperative cell as k_{((cell_ID+x)mod m)}Wherein, Cell _ ID is Cell identification, and m represents each cooperative Cell; mod is the remainder operator;

and x is a fixed value, or the value of x is notified to the target UE by the base station through signaling.

An apparatus for determining a location of a cell reference signal includes a selection module and a determination module, wherein,

the selection module is used for selecting a plurality of positions of the cooperation cells for transmitting the CSI-RS of each cooperation cell from the positions which can be used for sending the CSI-RS of different cells;

and the determining module is used for determining the position of the CSI-RS of each cooperative cell according to the identifier of each cooperative cell.

For each cell in the cells, all CSI-RSs in the cell are positioned on one or two Orthogonal Frequency Division Multiplexing (OFDM) symbols in one subframe;

the cell is a single cell or a cooperative cell.

When the subframe adopts a conventional cyclic prefix, the OFDM symbol is one or two OFDM symbols in a second, a third and a fourth OFDM symbols of a second time slot in the subframe;

when the sub-frame adopts the extended cyclic prefix, the OFDM symbol is one or two of a second OFDM symbol and a third OFDM symbol of a second time slot in the sub-frame.

Transmitting only the CSI-RS when the CSI-RS is transmitted on the same physical subcarrier as a reference signal of an antenna port # 5;

when the CSI-RS and data carried by a physical shared channel sent to an R8 version terminal are sent on the same physical subcarrier, only the CSI-RS is sent;

and the physical shared channel sent to the terminal above the R8 version is not mapped on the sub-carrier where the CSI-RS is positioned.

And the base station sends the identification of each cooperative cell according to the CSI-RS position of each cooperative cell and the corresponding sequence.

According to the technical scheme provided by the invention, the position of the reference signal CSI-RS of the channel state information of the cell is determined, and the user equipment UE measures the channel state information of a plurality of cells according to the position of the CSI-RS and reports the channel state information to the base station. When the cells are cooperative cells, selecting a plurality of positions of the cooperative cells for transmitting the CSI-RS of each cooperative cell from the positions which can be used for transmitting the CSI-RS of different cells; and determining the position of the CSI-RS of each cooperative cell according to the identification of each cooperative cell. By the method, the target UE determines the positions of the plurality of cells for sending the CSI reference signals, so that the aim of measuring the channel state information of the plurality of cells by the UE and reporting the channel state information to the base station so as to enable the base station to be used for data sending is fulfilled, the application of a CoMP technology is ensured, and the aim of improving the overall performance of the system is fulfilled.

Drawings

Fig. 1 is a schematic diagram of frame structures of FDD mode and TDD mode of an LTE system;

fig. 2 is a schematic structural diagram of a physical resource block when a system bandwidth of an LTE system is 5 MHz;

fig. 3a is a schematic diagram of the position of a cell common reference signal in a physical resource block when a cyclic prefix is a normal cyclic prefix in an LTE system;

fig. 3b is a schematic diagram of the position of a cell common reference signal in a physical resource block when a cyclic prefix is an extended cyclic prefix in an LTE system;

FIG. 4 is a flow chart of a method of determining a cooperative cell reference signal location of the present invention;

fig. 5 is a schematic structural diagram of the apparatus for determining the position of the reference signal of the cooperative cell according to the present invention.

Detailed Description

And determining the position of a reference signal CSI-RS of the channel state information of the cell, and measuring and reporting the channel state information of a plurality of cells to the base station by the user equipment UE according to the position of the CSI-RS.

Fig. 4 is a flowchart of a method for determining a reference signal position of a cooperative cell according to the present invention, as shown in fig. 4, including:

step 400: from the positions available for transmitting CSI-RSs of different cells, a number of positions of a cooperative cell for transmitting the CSI-RSs of each cooperative cell are selected.

It is assumed that the location sequence numbers currently available for transmitting CSI-RSs of different cells are k1, k 2.., kn, and the cell IDs related in the CoMP set are ID1, ID 2.., IDm, where m and n are integers.

In this step, selecting a plurality of locations of the cooperating cells for transmitting the CSI-RS of each cooperating cell specifically includes:

one implementation method is as follows: the m positions for transmitting the CSI-RS of the m cells are k_h，k_h+1，…，k_h+m-1The m positions are consecutive m positions. Wherein h is a fixed value, such as 0 or n-m; or h is preset, and the value of h is notified to the target UE by the base station through signaling.

The other realization method is as follows: the combination of m positions selected from all n positions is numbered, any m positions are guaranteed to be uniquely corresponding to a number index, and according to the positions of m cell CSI-RSs, a base station selects a number index to send to target UE; and the target UE acquires m pieces of position information according to the received number index and the corresponding relation between the number index and the position.

Suppose that the m positions are selected as

，1≤s_k≤n，s_k＜s_k+1Then, the number index r is as shown in equation (1):

<math> <mrow> <mi>r</mi> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>m</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>n</mi> <mo>-</mo> <msub> <mi>s</mi> <mi>k</mi> </msub> </mtd> </mtr> <mtr> <mtd> <mi>m</mi> <mo>-</mo> <mi>k</mi> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>

thus, the index of the number $r=0,...,\left(\begin{array}{c}n\\ m\end{array}\right)-1,$ Wherein, the definition of the expansion binomial coefficient is shown as formula (2):

<math> <mrow> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mfenced open='(' close=')'> <mtable> <mtr> <mtd> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> </mtd> <mtd> <mi>x</mi> <mo>&GreaterEqual;</mo> <mi>y</mi> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mi>x</mi> <mo>&lt;</mo> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow> </math>

in the formula (2), the first and second groups, $\left(\begin{array}{c}x\\ y\end{array}\right)$ represents the combination Cxy of y values out of the x different values.

The number indexes of the m positions for transmitting the m cell CSI-RSs are notified to the UE by the base station through signaling. The m positions of the m cell CSI-RSs are transmitted through m signaling, and each signaling represents the CSI-RS position of one cell.

Step 401: and determining the position of the CSI-RS of each cooperative cell according to the identification of each cooperative cell.

The specific implementation of this step is the following two methods:

the first method determines the location of the cell CSI-RS according to the order of the m cell identities transmitted by the base station, that is, the order of the m cell identities received by the UE. Such as: the order of cell IDi at m cell id transmission is g, then the position of its corresponding CSI-RS is the g-th position of the m positions.

A base station (eNB) needs to send m cell identifiers according to the CSI-RS positions of the m cells in a corresponding sequence;

and in the second method, the m cells are sorted according to the size of the cell identifier, and the position of the CSI-RS of the cell is determined according to the sorted position. Such as: the position of the cell IDi in the above ordering is g, then the position of its corresponding CSI-RS is the g-th position of the m positions.

In addition to the method shown in fig. 3, the present invention also provides a method of determining a cell reference signal.

First, from among the positions available for transmitting CSI-RS of different cells, a number of positions of a cooperating cell for transmitting CSI-RS of each cooperating cell are selected.

Then, assume that the locations currently available for transmitting CSI-RSs of different cells are k1, k 2.,kn, the cell IDs related in the CoMP set are ID1, ID2, and IDm, wherein m and n are integers; the Cell identification is Cell _ ID, and the position of the corresponding CSI-RS is k_{((cell_ID+x)mod m)}Wherein mod is a remainder operator; x is a fixed value, such as 0; or the value of x is notified to the target UE by the base station through signaling.

All CSI-RSs of one cell are located on one or two OFDM symbols in one subframe. Here, the cell refers to a single cell or a cooperative cell.

When the subframe adopts a conventional cyclic prefix, the OFDM symbol is one or two OFDM symbols in a second, a third and a fourth OFDM symbols of a second time slot in the subframe;

when the sub-frame adopts the extended cyclic prefix, the OFDM symbol is one or two of a second OFDM symbol and a third OFDM symbol of a second time slot in the sub-frame.

When the CSI-RS is transmitted on the same physical subcarrier as the reference signal of antenna port #5, only the CSI-RS is transmitted, and the reference signal of antenna port #5 is not transmitted, i.e. the reference signal of antenna port #5 on the subcarrier is dropped (Drop).

When data carried by a physical shared channel sent to an R8 version terminal and CSI-RS are sent on the same physical subcarrier, only the CSI-RS is sent, and the data carried by the physical shared channel is not sent;

the physical shared channel transmitted to the terminal above the R8 version is not mapped on the sub-carrier where the CSI-RS is located.

The method of the invention defines the position of the cell reference signal, thereby ensuring the application of the CoMP technology and achieving the aim of improving the overall performance of the system.

Fig. 5 is a schematic view of a structure of the apparatus for determining reference signals of a cooperating cell according to the present invention, and as shown in fig. 5, the apparatus includes a selecting module and a determining module, wherein,

and the selection module is used for selecting a plurality of positions of the cooperation cells for transmitting the CSI-RS of each cooperation cell from the positions which can be used for transmitting the CSI-RS of different cells.

And the determining module is used for determining the position of the CSI-RS of each cooperative cell according to the identifier of each cooperative cell.

The process of the invention is described below by way of example with reference to the examples.

In the first embodiment, assuming that the CSI-RS locations currently available for transmitting different cells are k1, k 2.,. kn, and the cell identifications related in CoMP set are ID1, ID 2.,. IDm, (m < n, and ID1 < ID 2. < IDm), then the CSI-RS location of cell IDi is k (h + i), where 1 ≦ i ≦ m, h, m, n is an integer.

That is, the cells in all CoMP sets are sorted according to the size of the cell identifier, and then mapped to the corresponding available CSI-RS positions in sequence according to the sorted order.

Wherein h is a fixed value, such as 0 or n-m; or the value of h is notified to the target UE by the base station through signaling.

In the second embodiment, assuming that the cell identifiers related in the CoMP set are ID1, ID2,. and IDm in the order in which the UE receives the cell identifiers, and the CSI-RS positions currently available for transmitting different cells are k1, k2,. and kn, then the CSI-RS position of the cell IDi is k (h + i), where i is greater than or equal to 1 and less than or equal to m, and h, m, and n are integers.

Wherein h is a fixed value, such as 0 or n-m; or the value of h is notified to the target UE by the base station through signaling.

A base station (eNB) needs to send m cell identifiers according to the CSI-RS positions of the m cells in a corresponding sequence;

in a third embodiment, the extended binomial coefficients are defined as <math> <mrow> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mfenced open='(' close=')'> <mtable> <mtr> <mtd> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> </mtd> <mtd> <mi>x</mi> <mo>&GreaterEqual;</mo> <mi>y</mi> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> </mtd> <mtd> <mi>x</mi> <mo>&lt;</mo> <mi>y</mi> </mtd> </mtr> </mtable> </mfenced> <mo>.</mo> </mrow> </math> Suppose that the m positions are selected as

，1≤s_k≤n，s_k＜s_k+1Then, the number index <math> <mrow> <mi>r</mi> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>m</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>n</mi> <mo>-</mo> <msub> <mi>s</mi> <mi>k</mi> </msub> </mtd> </mtr> <mtr> <mtd> <mi>m</mi> <mo>-</mo> <mi>k</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </math> I.e. number index $r=0,...,\left(\begin{array}{c}n\\ m\end{array}\right)-1.$

The decoding method is as follows:

the input parameter is r, the output parameter after decoding is

The first step is as follows: setting x_min＝1；k＝0；

Second oneThe method comprises the following steps: x ═ x_min， <math> <mrow> <mi>p</mi> <mo>=</mo> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>n</mi> <mo>-</mo> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>m</mi> <mo>-</mo> <mi>k</mi> </mtd> </mtr> </mtable> </mfenced> <mo>;</mo> </mrow> </math>

The third step: judging whether p > r is true, if so, x is x +1, <math> <mrow> <mi>p</mi> <mo>=</mo> <mfenced open='&lt;' close='&gt;'> <mtable> <mtr> <mtd> <mi>N</mi> <mo>-</mo> <mi>x</mi> </mtd> </mtr> <mtr> <mtd> <mi>m</mi> <mo>-</mo> <mi>k</mi> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </math> return execution

A third step; if not, executing the fourth step;

the fourth step: setting s_k＝x，x_min＝s_k+1，r＝r-p；

The fifth step: judging whether k is equal to m-1 or not, and if so, outputting

Ending the decoding process; if not, setting k to k +1, and returning to execute the second step.

Firstly, selecting a combination of m positions from all n positions for numbering, ensuring that any m positions are uniquely corresponding to a numbering index r, selecting a numbering index r by a base station according to the positions of m cell CSI-RSs and sending the numbering index r to target UE, and obtaining m pieces of position information by the target UE according to the received numbering index r and the corresponding relation between the numbering index r and the positions.

Then, the UE determines the position of the cell CSI-RS according to the received sequence of the m cell identifiers. That is, if the cell IDi has a transmission order g in m cell identifiers, the position of the corresponding CSI-RS is the g-th position in the m positions.

A base station (eNB) needs to send m cell identifiers according to the CSI-RS positions of the m cells in a corresponding sequence;

or,

sequencing the m cells according to the size of the cell identifier, and determining the positions of CSI-RSs of the cells according to the sequenced positions; that is, if the position of the cell IDi in the above ranking is g, the position of the corresponding CSI-RS is the g-th position among the m positions.

In the fourth embodiment, assuming that the relevant cells in the CoMP set are identified as ID1, ID 2.., IDm, and the CSI-RS positions currently available for transmitting different cells are k1, k 2.., kn, then the CSI-RS position of the cell IDi is k_{((IDi+x)mod m)}(i is more than or equal to 1 and less than or equal to m), and x, m and n are integers. Wherein x is a fixed value, such as 0 or n-m; or the value of x is notified by the base station through signaling.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.

Claims (19)

1. A method for determining a location of a cell reference signal, the method comprising:

and determining the position of a reference signal CSI-RS of the channel state information of the cell, and measuring and reporting the channel state information of a plurality of cells to the base station by the user equipment UE according to the position of the CSI-RS.

2. The method of claim 1, wherein the cell is a cooperative cell; the determining the location of the reference signal CSI-RS of the channel state information of the cell includes:

selecting a plurality of positions of a cooperative cell for transmitting CSI-RS of each cooperative cell from positions of reference signals CSI-RS which can be used for transmitting channel state information of different cells;

and determining the position of the CSI-RS of each cooperative cell according to the identification of each cooperative cell.

3. The method of claim 2, wherein the position order number k of the CSI-RS currently available for transmitting different cells is k₁，k₂，…，k_nSelecting a plurality of locations of a cooperating cell for transmitting each cooperating cell CSI-RS comprises:

the m positions for transmitting the CSI-RS of the m cells are k_h，k_h+1，…，k_h+m-1(ii) a The m positions are consecutive;

where m denotes each cooperative cell, and h is a fixed value or is preset.

4. The method according to claim 3, wherein when h is a fixed value, it takes a value of 0, or n-m;

where n represents the number of locations currently available for transmitting CSI-RS of different cells.

5. The method of claim 3, wherein when the h is preset, the value of the h is signaled to a target UE by a base station.

6. The method of claim 2, wherein the selecting the number of locations of the cooperating cells for transmitting the respective cooperating cell CSI-RS comprises:

selecting a combination of m positions from all n positions for numbering, wherein any m positions are uniquely corresponding to a numbering index r, and each numbering index r is uniquely corresponding to the m positions;

according to the positions of the CSI-RSs of the m cells, the base station selects a number index to send to the target UE;

the target UE obtains m pieces of position information according to the received number index r and the corresponding relation between the number index r and the position;

wherein n represents the number of positions currently available for transmitting CSI-RSs of different cells; m denotes each cooperative cell.

7. The method of claim 6, wherein the position order number k of the CSI-RS currently available for transmitting different cells is k₁，k₂，…，k_nThe selected m positions are

Wherein, 1 is less than or equal to s_k≤n，s_k＜s_k+1；

The number index $r=0,...,\left(\begin{array}{c}n\\ m\end{array}\right)-1,$ Wherein the definition of the extended binomial coefficients:

$\left(\begin{array}{c}x\\ y\end{array}\right)$ representing y out of x different valuesNumber of combinations of values C_x ^y。

8. The method of claim 6, wherein the number indices r of the m positions of the m cell CSI-RSs are signaled by a base station to a target UE.

9. The method of claim 2, wherein the m positions of the m cell CSI-RS are transmitted via m signaling, each signaling indicating a CSI-RS position of one cell.

10. The method of claim 2, wherein determining the location of each cooperating cell CSI-RS comprises: determining the position of a cell CSI-RS (channel state information-reference signal) according to the sequence of m cell identifiers sent by a base station;

or sequencing the m cells according to the size of the cell identifier, and determining the position of the CSI-RS of the cell according to the sequenced position.

11. The method according to claim 10, wherein the determining the location of the cell CSI-RS according to the order of the m cell identities transmitted by the base station specifically comprises:

and when the order of sending the cell ID in m cell identifiers is g, the position of the CSI-RS corresponding to the cell is the g-th position in the m positions.

12. The method of claim 10, wherein the m cells are ranked according to the size of the cell identifier, and determining the location of the cell CSI-RS according to the ranked location specifically comprises:

and when the position of the certain cell ID in the sequence is g, the position of the CSI-RS corresponding to the cell is the g-th position in the m positions.

13. The method of claim 2, wherein said determining eachThe position of the CSI-RS of the cooperative cell is k_{((cell_ID+x)modm)}Wherein, Cell _ ID is Cell identification, and m represents each cooperative Cell; mod is the remainder operator;

and x is a fixed value, or the value of x is notified to the target UE by the base station through signaling.

14. An apparatus for determining a location of a cell reference signal, comprising a selection module and a determination module, wherein,

the selection module is used for selecting a plurality of positions of the cooperation cells for transmitting the CSI-RS of each cooperation cell from the positions which can be used for sending the CSI-RS of different cells;

and the determining module is used for determining the position of the CSI-RS of each cooperative cell according to the identifier of each cooperative cell.

15. The apparatus of claim 1, wherein for each of the cells, all CSI-RSs in the cell are located on one or two orthogonal frequency division multiplexing, OFDM, symbols in one subframe;

the cell is a single cell or a cooperative cell.

16. The apparatus of claim 15, wherein the OFDM symbol is one of a second, third, and fourth OFDM symbol of a second slot in the subframe, or two OFDM symbols when the subframe employs a normal cyclic prefix;

when the sub-frame adopts the extended cyclic prefix, the OFDM symbol is one or two of a second OFDM symbol and a third OFDM symbol of a second time slot in the sub-frame.

17. The apparatus of claim 15,

transmitting only the CSI-RS when the CSI-RS is transmitted on the same physical subcarrier as a reference signal of an antenna port # 5.

18. The apparatus of claim 15,

when the CSI-RS and data carried by a physical shared channel sent to an R8 version terminal are sent on the same physical subcarrier, only the CSI-RS is sent;

and the physical shared channel sent to the terminal above the R8 version is not mapped on the sub-carrier where the CSI-RS is positioned.

19. The apparatus of claim 2, wherein the method further comprises:

and the base station sends the identification of each cooperative cell according to the CSI-RS position of each cooperative cell and the corresponding sequence.

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