RU2587992C2 - Method of configuring coordinated multipoint transmission - Google Patents

Abstract

FIELD: radio engineering and communications.

SUBSTANCE: present invention discloses a method of configuring coordinated multipoint (CoMP) transmission. Method involves providing a transmission mode for supporting CoMP and configuration in a base station (eNB) transmission mode for support of CoMP in user terminal (UE) through signalling RRC.

EFFECT: it becomes possible to configure a CoMP so that LTE system can maintain CoMP function.

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Description

FIELD OF THE INVENTION

The present invention relates to radio technology and, in particular, to a method for configuring a coordinated multi-point transmission (CoMP).

State of the art

Cellular mobile phones are extremely convenient for people to talk to, and the second-generation global system for mobile communication (GSM, global system for mobile communication) provides further improvement in the quality of mobile communications through the use of digital communication technologies. The 3rd Generation Communications Standardization Consortium (3GPP), a leading organization in the field of mobile communications, has actively promoted the standardization of 3rd generation (3G) mobile communications technology and has developed a series of communications system standards, such as WCDMA (wide code division multiple access, broadband code division multiple access), HSDPA (high speed downlink packet access, and HSUPA (high speed uplink packet access).

To solve the problems associated with the technology of broadband access and to meet the growing demand for new services, the 3GPP Consortium at the end of 2004 began standardizing the long-term development (LTE, long-term evolution) of 3G networks, planning to improve the efficiency of spectrum use and the characteristics of user devices at the borders cells, reduce system latency and provide high-speed access services for fast moving mobile users.

CoMP is a joint coordinated transmission of multiple transmitting points (eg, base stations) geographically remote from each other. Currently, two architectures can be used to implement CoMP. The name of one of them is joint processing (JP), the other is called coordinated scheduling / coordinated beamforming (CS / CB). In turn, the JP architecture uses two schemes: joint transmission (JT) and fast cell selection (PCS). In particular, the JT scheme implements the simultaneous transmission of data from multiple transmitting points to one user, and in the FCS scheme, the data is transmitted to the user from one transmitting point.

Currently, LTE version 8 (LTE Release 8) defines 7 transmission modes (TM). Here, various transmission modes are understood as various functions, for example, multiple input and multiple output channels for a single user (single user multiple-input multiple-output, SU-MIMO) with a closed circuit, SU-MIMO with an open circuit, many input and many output channels for multiple users (multi-user multiple-input multiple-output, MU-MIMO) and transmit diversity. LTE version 9 (LTE Release 9) supports dynamic SU / MU-MIMO switching, as well as a new mode of transmission of up to two data streams, inclusively for each user. In LTE version 10 (LTE Release 10) standards, dynamic SU / MU-MIMO switching is supported, and a new transmission mode is proposed for up to eight data streams inclusively for each user. In the LTE system, the configuration of the current transmission mode of each user terminal (UE, user equipment, user device) is performed using higher level signaling. In addition, in the LTE system, the quasistatic switching between different transmission modes for each UE is controlled by higher level signaling. However, since 9 standard transmission modes are designed for single-point data transmission and do not support CoMP, the CoMP mode cannot be configured in the current LTE system, which makes it difficult to implement CoMP.

In view of the foregoing, the present invention has been developed, the purpose of which is to propose a method for configuring CoMP mode. This scheme makes it possible to specify CoMP in the LTE system and, therefore, support for CoMP mode by the LTE system.

Disclosure of invention

The present invention discloses a method for configuring coordinated multipoint transmission (CoMP), comprising the steps of providing a transmission mode to support CoMP; and configuring the base station (eNB) transmission mode to support CoMP in the user terminal (UE) by signaling the radio resource control (RRC) level.

In addition, the method described above further comprises the steps of: at the base station after receiving the reception power of the reference signal, the composition of CoMP participants for the user terminal is determined as feedback from the user terminal, and the composition of CoMP participants for the user terminal and the feedback mode are reported to the user terminal communications for channel status information (CSI) through RRC signaling; CSI information is transmitted from the user terminal to the base station as feedback based on the composition of the participants of CoMP and feedback mode for CSI information reported from the base station; and in the base station, scheduling is performed based on the CSI information transmitted from the user terminal as feedback, and scheduling results are reported to the user terminal.

Here, at the stage of providing a transmission mode for supporting CoMP, the standard transmission modes, mode 8 and mode 9, for supporting CoMP are expanded.

The downstream control signaling corresponding to the extended transmission mode, mode 8, is in 2V DCI format.

The downstream control signaling corresponding to the extended transmission mode, mode 9, is in 2C DCI format.

In the step of providing a transmission mode for supporting CoMP, a first transmission mode for supporting CoMP coordinated scheduling / coordinated beamforming and a second transmission mode for supporting CoMP processing co-processing are provided; or provide a first transmission mode to support both CoMP coordinated scheduling / coordinated beamforming schemes and co-processing CoMP schemes.

In the described method, as a downlink control signaling corresponding to the first transmission mode or the second transmission mode, the 2V DCI format is used in its original form or the 2B DCI format is expanded to add a multi-user information field with a length of 1 to 3 bits that specifies information for the user terminal to participate in joint scheduling, and this extended 2V DCI format is used as a downlink control signaling corresponding to a first transmission mode or a second transmission mode. Alternatively, as a downstream control signaling corresponding to the first transmission mode or the second transmission mode, DCI 2C format is used in its original form or DCI 2C format is expanded to add a multi-user information field with a length of 1 to 7 bits that specifies information for the user terminal to participate in joint scheduling, and the extended DCI 2C format is used as a downlink control signaling corresponding to a first transmission mode or a second transmission mode. In another embodiment, the DCI 2C format is changed with decreasing the length of the MIMO information field from 3 bits to 2 bits, and this modified DCI 2C format is used as a downstream control signaling corresponding to the first transmission mode or second transmission mode, or the DCI 2C format is changed with decreasing length MIMO information field from 3 bits to 2 bits and the addition of a multi-user information field with a length of 1 to 7 bits that specifies information for the user terminal to participate in joint planning, and this modified form 2C atom DCI is used as a downlink control signaling according to a first transmission mode or a second transmission mode. Alternatively, the standard 1B DCI format is changed to remove the TPMI field and the PMI field from it, and this changed 1B DCI format is used as a downlink control signal corresponding to the first transmission mode or the second transmission mode.

The technical result of the invention.

As follows from the foregoing, in accordance with the above method, a transmission mode is provided for supporting CoMP, and a transmission mode is configured to support CoMP in the user terminal by means of RRC signaling. This scheme makes it possible to implement CoMP configuration and support CoMP function in the LTE system.

Brief Description of the Drawings

Figure 1 shows a diagram of a method for configuring CoMP according to an embodiment of the present invention.

Figure 2 shows a diagram of a specific method for configuring CoMP according to an embodiment of the present invention.

The implementation of the invention

The purpose, means of solution and advantages of the present invention are described in detail below with reference to the drawings and using examples.

In an embodiment of the present invention, there is provided a CoMP configuration method providing CoMP support for an LTE system. Figure 1 shows the following basic steps of this method.

At step 101, a transmission mode is provided to support CoMP.

In step 102, the base station (eNB) on the LTE access network side configures the transmission mode to support CoMP in the user terminal (UE) using the radio resource control (RRC) level signaling.

As shown in FIG. 2, after the base station (eNB) has configured a transmission mode to support CoMP in a user terminal (UE), the configuration of CoMP can be specifically implemented by performing the following steps.

In step 201, after receiving the reference signal receiving power (RSRP) as feedback from the UE, the eNB determines the membership of the CoMP (cooperating set) for the user terminal (UE) and, using the RRC signaling, reports to the UE the composition CoMP participants for the UE and feedback mode for channel status information (CSI).

At this step, the eNB can determine the membership of CoMP for the UE in any standard way or in any of the new ways that will become available in the future.

In addition, for the purpose of reporting to the UE the composition of CoMP participants for the UE and the feedback mode for CSI, at this step the message configuration report with channel quality information (CQI-ReportConfig) in the RRC signaling can be extended to associate the composition of CoMP participants for the UE and feedback mode for CSI. Thus, the eNB can report to the UE the composition of the CoMP participants for the UE and the feedback mode for the CSI by means of the CQI-ReportConfig message in the RRC signaling.

In step 202, the UE as a feedback sends CSI information to the eNB based on the composition of the participants of the CoMP and the feedback mode for the CSI reported from the eNB.

In step 203, the eNB uses the CSI received as feedback from the UE as the basis for scheduling and informs the user of the scheduling result. In other words, the eNB determines which of the schemes to use for the user terminal (UE) —the CS / CB CoMP transmission scheme or the JP CoMP transmission scheme — and reports the determination result to the UE.

In this step, the eNB can plan in any standard way or in any of the new ways that will become available in the future.

To implement the above step 101, an embodiment of the present invention provides many methods for providing a transmission mode for supporting CoMP.

In addition, in various transmission modes, the eNB must configure various information regarding the reception of data (for example, the modulation and coding scheme (MCS, modulation and coding scheme) of the user terminal (UE), the resources allocated to the UE, and so on) in the UE, with using downlink control signaling. In order to satisfy this need, in an embodiment of the present invention, it is necessary to provide, in addition to the transmission mode for supporting CoMP, the presence of a downlink control signaling corresponding to this transmission mode. In particular, providing a downlink control signaling corresponding to a transmission mode means providing a downlink control information format (DCI) corresponding to a transmission mode.

In the following description, various methods for providing a transmission mode for supporting CoMP and the corresponding DCI format using specific examples are described in detail.

Method 1:

The standard transmission modes (mode 8 and mode 9) are expanded so that the advanced transmission modes (mode 8 and mode 9) can support CoMP. The definition of advanced transmission modes (mode 8 and mode 9) is given below in tables 1 and 2.

Table 1 Transmission mode DCI format Description Mode 8 1A DCI format Exists in the common search space and in the search space, individual for the UE, and is scrambled using the C-RNTI (Cell Radio Network Temporary Identifier, temporary identifier in the cellular radio network) of the user terminal (UE). (General and individual for UE due to C-RNTI). When the number of antenna ports of the physical broadcast channel (PBCH) is 1, this means that there is a single antenna port, port 0 is used. When the number of antenna ports of the PBCH is not 1, transmission diversity is used. 2V DCI format Exists in a search space specific to a UE, and is scrambled using a C-RNTI user terminal (UE). (Individual for UE due to C-RNTI) Data is transmitted in two streams using ports 7 and 8, or a single antenna port is used, ports 7 and 8 are used, and CoMP is supported (for example, CS / CB, JP).

table 2 Transmission mode DCI format Description Mode 9 1A DCI format General and individual for UE due to C-RNTI When the number of antenna ports of the Strategic Rocket Forces is 1, this means that there is a single antenna port, and port 0 is used. When the number of antenna ports of the Strategic Rocket Forces is not 1, transmit diversity is used. 2C DCI format Customized for UE with C-RNTI Dynamic SU / MU switching is enabled, a large number of SU data streams are supported, and CoMP is supported (e.g. CS / CB, JP).

As can be seen from table 1, the advanced mode 8 transmission can support CoMP, and this mode corresponds to the downstream control signaling format 2B DCI. In particular, on the LTE access network side, a standard 2B DCI format corresponding to the extended transmission mode 8 can be directly used as a downlink control signaling.

In addition, it can be seen from Table 2 that the advanced transmission mode 9 can support CoMP, and this mode corresponds to the DCI format 2C of the downlink control signaling. In particular, on the LTE access network side, a standard DCI 2C format corresponding to the extended transmission mode 9 can be directly used as a downlink control signaling.

Using this method, it is possible to provide a transmission mode to support CoMP and its corresponding downstream control signaling. This means that using this method, the implementation of step 101 is possible. In this case, at step 102, the eNB can configure by means of the RRC signaling whether to perform single-point or multi-point CSI transmission for the user as feedback. The base station (eNB) may select a single-point or multi-point transmission after receiving the CSI as feedback from the UE, without having to report this to the UE. Therefore, the above method can support dynamic switching between single-point and multi-point transmission.

Method 2:

The new first and second transmission modes corresponding to the two types of CoMP, that is, CS / CB and JP, are determined, a new downstream control signaling is provided corresponding to the first and second transmission modes, in order to support CoMP, it can be noted that the new first transmission mode (mode 10 ), and the new second transmission mode (mode 11), are defined as shown in Table 3 below. It should be clarified that in the implementation of the present invention, the downstream control signaling corresponding to the first and second transmission modes is convenient for yasneniya called 2D / 2E DCI format.

Table 3 Transmission mode DCI format Description Mode 10 1A DCI format General and individual for UE due to C-RNTI When the number of antenna ports of the Strategic Rocket Forces is 1, this means that there is a single antenna port, and port 0 is used. When the number of antenna ports of the Strategic Rocket Forces is not 1, transmit diversity is used. 2D DCI format Customized for UE with C-RNTI CS / CB Mode 11 1A DCI format General and individual for UE due to C-RNTI When the number of antenna ports of the Strategic Rocket Forces is 1, this means that there is a single antenna port, and port 0 is used. When the number of antenna ports of the Strategic Rocket Forces is not 1, transmit diversity is used. 2D / 2E DCI format Customized for UE with C-RNTI JP

As can be seen from table 3, the provided new first transmission mode (mode 10) supports the CS / CB CoMP scheme, and the corresponding DCI format is the new 2D DCI format. The provided new second transmission mode (mode 11) supports the JP CoMP scheme, and its corresponding DCI format is the new 2D / 2E DCI format.

In particular, in this embodiment of the present invention, the new 2D / 2E DCI format can be configured using any of the following methods:

1) Use of 2V DCI format without changes as 2D / 2E DCI format.

2) Adding to the 2B DCI format a multi-user information field, for example, from 1 to 3 bits in length, specifying information for the UE to participate in joint scheduling (for example, the demodulation reference signal port information of the UE to participate in joint scheduling , the length of the orthogonal cover code (OCC) or the total number of DMRS ports, DMRS density, etc.) in order to expand the 2 V DCI format in this way and use this extended 2 V DCI format as the 2D / 2E DCI format . The specific configuration of this format is disclosed below in table 4.

Table 4 Field Length (bits) Resource Allocation Header 0 or 1 Assigning a Resource Block TPC Team for PUCCH 2 Downlink Destination Index 2 HARQ Process Number 3 or 4 TV1 MCS 5 TV1 NDI one TV1 RV 2 TV2 MCS 5 TV2 NDI one TB2 RV 2 Multi-user information field 1-3

3) Use of 2C DCI format without changes as a 2D / 2E DCI format.

4) Adding to the 2C DCI format a multi-user information field, for example, from 1 to 7 bits in length, defining information for the UE to participate in joint planning, in order to expand the 2C DCI format in this way and use this extended 2C DCI format as the 2D / 2E DCI. The specific configuration of this format is disclosed below in table 5.

Table 5 Field Length (bits) Resource Allocation Header 1 or 0 Assigning a Resource Block TPC Team for PUCCH 2 Downlink Destination Index 2 HARQ Process Number 3 or 4 TV1 MCS 5 TV1 ND1 one TV1 RV 2 TV2 MCS 5 TV2 NDI one TB2 RV 2 MIMO Information Field 3 Multi-user information field 1-7

5) Changing the DCI 2C format to reduce the number of bits of the MIMO information field indicating DMRS port information, scrambling sequence index), the number of data streams (rank) of the UE, etc., from 3 bits to 2 bits, and use of this modified 2C DCI format as a 2D / 2E DCI format. The specific configuration of this format is disclosed below in table 6.

Table 6 Field Length (bits) Resource Allocation Header 1 or 0 Assigning a Resource Block TPC Team for PUCCH 2 Downlink Destination Index 2 HARQ Process Number 3 or 4 TV1 MCS 5 TV1 NDI one TV1 RV 2 TV2 MCS 5 TV2 NDI one TB2 RV 2 MIMO Information Field 2

6) Changing the DCI 2C format to reduce the number of bits of the MIMO information field indicating DMRS port information, SCID, UE rank, etc., from 3 bits to 2 bits, and adding a multi-user information field of length, for example, from 1 to 7 bits defining information for the UE to participate in joint planning, and the use of this modified 2C DCI format as a 2D / 2E DCI format. The specific configuration of this format is disclosed below in table 7.

Table 7 Field Length (bits) Resource Allocation Header 1 or 0 Assigning a Resource Block TPC Team for PUCCH 2 Downlink Destination Index 2 HARQ Process Number 3 or 4 TV1 MCS 5 TV1 NDI one TV1 RV 2 TV2 MCS 5 TV2 NDI one TB2 RV 2 MIMO Information Field 2 Multi-user information field 1-7

7) Removing the precoding index field (TPMI) from the standard 1V DCI format and the precoding type index field (PMI), and using this modified 1B DCI format as the 2D / 2E DCI format. The specific configuration of this format is disclosed below in table 8.

Table 8 Field Length (bits) VRB Localized / Distributed Flag one Assigning a Resource Block Mcs 5 HARQ Process Number 3 or 4 Ndi one RV 2 TPC Team for PUCCH 2 Downlink Destination Index 2

8) Further reduction of the 1V DCI format and the addition of an additional restriction to it. It is necessary, for example, to allocate resources in sequential order.

In the above methods, after receiving the CSI, the single-point or multi-point transmission may be determined by the eNB as feedback from the UE. However, reporting the selected transmission mode to the UE is optional. In other words, the above methods support dynamic switching between single-point and multi-point transmission.

Method 3:

A unified transmission mode is provided for CS / CB and JP, i.e. the first transmission mode, mode 10, and a new DCI format is provided, thereby providing support for CoMP. This method aims to optimize the performance of the CS / CB mode, and user feedback is provided for appropriate CS / CB support. The eNB may select single-point transmission, multi-point transmission for CS / CB and JP, however, it is not necessary to report a choice between single-point and multi-point transmission in the UE. That is, the aforementioned method supports dynamic switching between single-point and multi-point transmission. The definition of the new first transmission mode (mode 10) is given below in table 9.

Table 9 Transmission mode DCI format Description Mode 10 1A DCI format General and individual for UE due to C-RNTI When the number of antenna ports of the Strategic Rocket Forces is 1, this means that there is a single antenna port, and port 0 is used. When the number of antenna ports of the Strategic Rocket Forces is not 1, transmit diversity is used. 2D DCI format Customized for UE with C-RNTI CS / CB (JP)

As can be seen from table 9, the proposed new first transmission mode (mode 10) supports the CS / CB (JP) CoMP scheme, and its corresponding downstream control signaling has a new DCI format - 2D DCI format. As described above, the new 2D DCI format can be configured using any of a variety of methods, including methods 1-7 described above.

Method 4:

A unified transmission mode is provided for CS / CB and JP, i.e. the first transmission mode, mode 10, and a new DCI format is provided, thereby providing support for CoMP. This method aims to optimize JP mode performance and provides user feedback for appropriate CS / CB support. The eNB can select single-point transmission, multi-point transmission for CS / CB and JP, however, it is not necessary to report the choice between single-point and multi-point transmission in the UE. That is, the aforementioned method supports dynamic switching between single-point and multi-point transmission. The definition of the new first transmission mode (mode 10) is given below in table 10.

Table 10 Transmission mode WINC format (DCI) Description Mode 10 1A DCI format General and individual for UE due to C-RNTI When the number of antenna ports of the Strategic Rocket Forces is 1, this means that there is a single antenna port, port 0 is used. When the number of antenna ports of the Strategic Rocket Forces is not 1, transmission diversity is used 2D DCI format Customized for UE with C-RNTI JP (CS / CB)

As can be seen from table 10, the new first transmission mode (mode 10) supports the CS / CB CoMP scheme, and its corresponding downstream control signaling has a new DCI format - 2D DCI format. As described above, the new 2D DCI format can be configured using any of a variety of methods, including methods 1-7 described above.

As described above, since the transmission mode for supporting CoMP may be provided by any of the above methods 1 to 4, CoMP may be configured so that the LTE system can support CoMP. Further, using any of the above methods 1-4, it is also possible to provide a DCI format for downlink control signaling corresponding to a transmission mode for supporting CoMP. In addition, using the downlink control signaling thus provided, the eNB can transmit information necessary for receiving downlink data to the UE. This scheme allows the UE to properly receive downstream data.

Preferred embodiments of the present invention, disclosed up to this point, were presented for illustrative purposes only, and are not intended to limit the scope of protection of the present invention. It should be noted that various modifications, equivalent replacements or improvements, not going beyond the principles of the present invention, fall within the protection scope of the present invention.

Chinese Patent Application No. 20111111266.X, filed April 22, 2011, including the description, drawings and abstract, is incorporated herein by reference in full.

Claims (7)

1. A method for configuring a coordinated multipoint transmission (CoMP), comprising the steps of:
in the base station, a transmission mode is reported to the user terminal to support CoMP by signaling a radio resource control (RRC) layer. 2. The method according to p. 1, characterized in that the format of the downlink control information (DCI) corresponding to the transmission mode for supporting CoMP includes 2D DCI format. 3. The method according to p. 2, characterized in that the 2D DCI format is located in the search space, individual for the user terminal, based on the temporary identifier in the cellular radio network (C-RNTI). 4. The method according to any one of paragraphs. 1-3, characterized in that it further comprises stages in which:
in the base station, a feedback mode for channel status information (CSI) is reported to the user terminal, and
CSI information is transmitted from the user terminal to the base station based on the transmission mode and the feedback mode for the CSI information. 5. A base station for configuring coordinated multipoint transmission (CoMP), configured to communicate to a user terminal a transmission mode for supporting CoMP via RRC signaling. 6. A user terminal for configuring coordinated multipoint transmission (CoMP), configured to configure a transmission mode to support CoMP reported from the base station via RRC signaling. 7. A radio communication system for configuring coordinated multipoint transmission (CoMP), in which the base station communicates a transmission mode to the user terminal to support CoMP via RRC signaling.

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