CN103560816A - Method for multi-antenna multi-base-station cooperation of downlink cellular system and base station - Google Patents

Abstract

A method for multi-antenna and multi-base station cooperation of a downlink cellular system and a base station are disclosed. First, the serving base station judges whether the user equipment enters the multi-antenna multi-base station cooperation mode. If the condition is satisfied, the serving base station uses downlink control signaling to configure the user equipment, and then the user equipment obtains the system information of the serving base station and each cooperative base station And channel state information, and feedback, so the serving base station obtains the channel state information of the downlink channel from the user equipment to the serving base station and each cooperative base station, performs resource scheduling and background communication, and finally, the user equipment obtains the allocation instruction of downlink resources. The serving base station and each cooperative base station send data to the user equipment in a manner of multi-antenna and multi-base station cooperation. The invention has the advantages of wide application range, reasonable signaling, easy realization and the like.

Description

Multi-antenna multi-base station cooperation method and base station in downlink cellular system

This application is a divisional application of the application No. 200810146047.3 entitled "Multi-antenna and multi-base station cooperation method and base station for downlink cellular system" submitted on August 8, 2008.

technical field

The present invention relates to a method for multi-antenna and multi-base station cooperation in the field of communication technology and a base station using the method, and more specifically, relates to a method for improving the downlink data transmission rate through multi-antenna and multi-base station cooperation in downlink cellular systems and a base station using the method.

Background technique

Multi-antenna (MIMO: Multiple In Multiple Out) wireless transmission technology configures multiple antennas at the transmitter and receiver to utilize the space resources in wireless transmission to obtain spatial multiplexing gain and space diversity gain. Research on information theory shows that the capacity of a MIMO system increases linearly with the minimum number of transmitting antennas and receiving antennas. A schematic diagram of a MIMO system is shown in FIG. 1 . In FIG. 1 , multiple antennas at a transmitting end and a receiving end constitute a multi-antenna wireless channel, including airspace information. In addition, OFDM technology (orthogonal frequency division multiplexing) has strong anti-fading ability and high frequency utilization rate, and is suitable for high-speed data transmission in multi-path environment and fading environment. MIMO-OFDM technology, which combines MIMO technology and OFDM technology, has become the core technology of the new generation of mobile communication.

For example, 3GPP (Third Generation Partnership Project) organization is an international organization in the field of mobile communication, and she plays an important role in the standardization work of 3G cellular communication technology. The 3GPP organization began to design EUTRA (Evolved Universal Mobile Telecommunications System and Terrestrial Radio Access Network) and EUTRAN (Evolved Universal Mobile Telecommunications System Network and Terrestrial Radio Access Network) from the second half of 2004. This project is also known as LTE (Long Term Evolution) project. The downlink of the LTE system uses MIMO-OFDM technology. In April 2008, 3GPP organization began to discuss the standardization of 4G cellular communication system at the meeting in Shenzhen, China. At the meeting, a concept called "multi-antenna and multi-base station cooperation" received widespread attention and support. Its core idea is to use multiple base stations to provide communication services for one user or multiple users at the same time, thereby improving the data of cell border users. Transmission rate.

In some technical documents, there are three multi-antenna multi-base station cooperation methods for downlink cellular systems:

(1) Method based on aggregated signals: The mobile station selects its pattern according to information such as distributed base stations and its own location. There are multiple directions with relatively strong field strengths in the pattern, which point to different base station antennas. The distributed base station selects the appropriate base station and its antenna according to the specific geographical location of the mobile station to perform aggregation operations through cooperation, forming an aggregation field around the mobile station, so that the antenna of the mobile station is in a position with a relatively strong field strength. See Patent Document 1 "A Distributed Multi-Antenna Communication Method and System Based on Aggregated Signals", Chinese Patent Application Publication No., CN101047415.

(2) The method based on virtual MIMO technology: multiple antennas of multiple base stations are regarded as a virtual single base station MIMO system with more antennas, so as to obtain greater spatial multiplexing and spatial diversity gains. In addition, the mechanism of reusing a single base station MIMO system helps to reduce the implementation complexity of a multi-antenna multi-base station system. See non-patent literature 1: 3GPP, R1-082501, "Collaborative MIMO for LTE-A downlink", Alcatel-Lucent (3GPP document, number: R1-082501, "Collaborative MIMO technology in LTE-A downlink system", Alcatel -Lucent Corporation).

(3) The method based on the independent operation of a single base station: a single base station equipped with multiple antennas independently provides services for user equipment, and then the user equipment superimposes the data of multiple single base stations to obtain higher spatial multiplexing and spatial diversity gains. The method is simple to implement, and the signaling overhead is small. See Non-Patent Document 2: 3GPP, R1-082497, "Network MIMO Preeoding", Texas Instruments (3GPP document, number: R1-082497, "Precoding of Network MIMO Systems", Texas Instruments).

However, the first method is only multi-antenna multi-base station cooperation in the energy sense, and the system performance is closely related to the geographical location, resulting in limited application scope; the second method focuses on conceptual elaboration, for user configuration in multi-antenna multi-base station, Important issues such as user feedback have not been further discussed; method 3 is simple to implement, but the completely independent single-base station operation does not reflect the advantages of multi-antenna and multi-base station cooperation, so its performance is poor.

Contents of the invention

The object of the present invention is to provide a multi-antenna and multi-base station cooperation method and base station for a downlink cellular system in view of the shortcomings of limited application range or incomplete system design in the prior art.

In the first aspect of the present invention, a method for multi-antenna and multi-base station cooperation in a downlink cellular system is proposed. The downlink cellular system includes at least one user equipment, a serving base station and at least one cooperative base station providing services to the user equipment. The method includes the following steps: the serving base station judges whether there is a user equipment that enters a multi-antenna multi-base station cooperative working mode; the serving base station uses downlink control signaling to configure the user equipment that enters the working mode; the user equipment obtains the serving base station and the user equipment based on the configuration. The system information of each cooperative base station and the channel state information of the downlink channel required for resource allocation; the user equipment feeds back the channel state information of the downlink channel required for resource allocation to the serving base station; the serving base station is based on the channel state of the downlink channel required for resource allocation information, perform resource scheduling, and send at least resource scheduling results and downlink communication data to each cooperative base station; and at least send downlink resource allocation instructions from the serving base station to the user equipment.

According to an embodiment of the present invention, the serving base station judges whether a user equipment enters a multi-antenna multi-base station cooperation mode based on at least one of the following factors: the geographical location of the user equipment, the path loss of the user equipment, and the downlink data buffering status of the user equipment .

According to an embodiment of the present invention, the downlink control signaling includes configuration information, and the configuration information at least includes: a cell number of a cooperative base station, and a transmission mode of downlink data.

According to an embodiment of the present invention, the downlink control signaling includes configuration information, and the configuration information includes at least: the cell number and antenna configuration of the cooperative base station.

According to an embodiment of the present invention, the system information of the serving base station and each cooperative base station obtained by the user equipment includes at least antenna configuration.

According to the embodiment of the present invention, the user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, and the user equipment obtains the system information of each cooperative base station through the broadcast channels of each cooperative base station.

According to the embodiment of the present invention, the user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, and the user equipment obtains the system information of each cooperative base station through the configuration information.

According to the embodiment of the present invention, the user equipment only feeds back the channel state information of the downlink channel required for resource allocation to the serving base station.

According to the embodiment of the present invention, the user equipment respectively feeds back the channel state information of the downlink channel required for resource allocation to the serving base station and each cooperative base station.

According to the embodiment of the present invention, the serving base station obtains the channel state information of the downlink channel required for resource allocation through feedback from the user equipment.

According to the embodiment of the present invention, each cooperative base station transmits the channel state information of the downlink channel required by the serving base station in resource allocation to the serving base station through the background.

According to an embodiment of the present invention, the allocation instruction includes at least one of the frequency position of the downlink resource and precoding information required for the serving base station to send data.

According to an embodiment of the present invention, the allocation indication includes at least one of the frequency position of the downlink resource, the precoding information required for the serving base station to send data, and the precoding information required for each cooperative base station to send data.

According to an embodiment of the present invention, at least sending the downlink resource allocation indication from the serving base station to the user equipment includes: the serving base station and each cooperative base station respectively send downlink resource allocation indications to the user equipment, and the allocation indication includes at least the frequency of the downlink resource The location and the precoding information required for the base station to send data.

In another aspect of the present invention, a base station is also proposed, which is used as a serving base station and at least one cooperative base station to realize multi-antenna and multi-base station cooperation of a downlink cellular system. The base station includes the following steps: a judging unit, judging whether there is a user equipment entering a multi-antenna multi-base station cooperation mode; a downlink control signaling sending unit, using downlink control signaling to configure the user equipment entering the working mode; a resource scheduling unit , receiving the channel state information of the downlink channel required for resource allocation fed back from the user equipment, performing resource scheduling based on the channel state information, and sending at least resource scheduling results and downlink communication data to each cooperative base station; and an allocation indication sending unit, to The user equipment sends an indication of allocation of downlink resources.

Therefore, the multi-antenna multi-base station cooperation method and base station of the downlink cellular system proposed by the present invention include user configuration, user feedback, resource allocation indication, etc., and have the advantages of wide application range, reasonable signaling, and easy implementation.

Description of drawings

The above-mentioned and other purposes, features and advantages of the present invention will be made clearer by illustrating preferred embodiments of the present invention in conjunction with the accompanying drawings below, wherein:

Fig. 1 is the schematic diagram of MIMO system;

2 is a schematic diagram of a multi-cell cellular communication system;

3 is a schematic block diagram of a base station implementing a multi-antenna and multi-base station cooperation method in a downlink cellular system according to an embodiment of the present invention;

FIG. 4 is a flowchart of a multi-antenna and multi-base station cooperation method in a downlink cellular system according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an application example 1 of an embodiment of the present invention;

Fig. 6 is a schematic diagram of application example 2 of the embodiment of the present invention;

Fig. 7 is a schematic diagram of application example 3 of the embodiment of the present invention;

FIG. 8 is a schematic diagram of application example 4 of the embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and unnecessary details and functions for the present invention will be omitted during the description to avoid confusing the understanding of the present invention.

In order to clarify and describe the implementation steps of the present invention in detail, some specific embodiments of the present invention are given below, which are applicable to the downlink LTE cellular communication system. It should be noted that the present invention is not limited to the applications described in the embodiments, but is applicable to other communication systems.

Referring to FIG. 2, a schematic diagram of a multi-cell cellular communication system is shown. Cellular systems divide the service coverage area into contiguous wireless coverage areas, ie cells. In FIG. 2 , a cell is schematically depicted as a regular hexagon, and the entire service area is composed of cells 100 - 104 . Associated with cells 100-104, respectively, are base stations 200-204. Each of the base stations 200-204 includes a transmitter, a receiver, and a base station control unit, as is known in the art. In Fig. 2, base stations 200-204 are schematically depicted as being located in a certain area of cells 100-104 and equipped with omni-directional antennas. However, in the cell layout of the cellular communication system, the base stations 200-204 may be equipped with directional antennas to directionally cover a part of the cells 100-104, which is usually called a sector. Therefore, the representation of the multi-cell cellular communication system in FIG. 2 is only for illustrative purposes, and does not mean that the present invention requires the above-mentioned restrictive specific conditions in the implementation of the cellular system.

In FIG. 2, base stations 200-204 are connected to each other through X2 interfaces 300-304. In the LTE system, the three-layer node network structure of the base station, the radio network control unit and the core network is simplified into a two-layer node structure. Among them, the function of the wireless network control unit is divided into the base station, and the base station coordinates and communicates with the base station through a wired interface named "X2".

In FIG. 2, several user equipments 400-430 are distributed in cells 100-104. Each of the user equipments 400-430 includes a transmitter, a receiver, and a mobile terminal control unit, as is known in the art. The user equipments 400-430 access the cellular communication system through their respective serving base stations (one of the base stations 200-204). It should be understood that although only 16 user equipments are schematically shown in FIG. 2 , the number of user equipments in actual situations is quite huge. In this sense, the depiction of the user equipment in FIG. 2 is only for illustrative purposes. The user equipments 400-430 access the cellular communication network through the base stations 200-204 serving for them respectively. The base station that directly provides communication services for a certain user equipment is called the serving base station of the user equipment, and other base stations are called the non-communication base stations of the user equipment. The serving base station and the non-serving base station can serve as cooperative base stations of the serving base station to provide communication services for users together.

FIG. 3 is a schematic block diagram of a base station using a multi-antenna and multi-base station cooperation method for a downlink cellular system according to an embodiment of the present invention.

As shown in FIG. 3 , base stations 200, 202, and 204 according to embodiments of the present invention include: user equipment parameter memory 211, judging unit 212, downlink control signaling sending unit 213, allocation instruction sending unit 215, and resource scheduler 214.

The user equipment parameter storage 211 stores relevant parameters of the user equipment in the base stations 200 , 202 , and 204 . The relevant parameters of the user equipment include but are not limited to: the geographical location of the user equipment and/or the path loss of the user equipment and/or the condition of downlink data buffering of the user equipment.

The judging unit 212 judges whether the user equipment enters the working mode of multi-antenna multi-base station cooperation according to the related parameters of the user equipment stored in the user equipment parameter memory 211 .

The downlink control signaling sending unit 213 is configured to send downlink control signaling through the downlink air interface, so as to configure the user equipment in a multi-antenna and multi-base station working mode.

The resource scheduler 214 receives the channel state information of the downlink channel required for resource allocation sent from the user equipment, and performs resource scheduling according to the channel state information from the user equipment, and performs background communication through the X2 interface, and sends the resource scheduling to the cooperative base station results and downlink data;

The allocation indication unit 215 sends an allocation indication of downlink resources to the user equipment according to the scheduling result of the resource scheduler 214 . The base stations 200, 202, 204 communicate through the X2 interface.

In this example, considering the specific configuration of the LTE system, refer to the document of the 3GPP organization: TS36.213V8.3.0, "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Layer Procedures" (Evolved Universal Terrestrial Radio Access physical layer process). It defines 7 kinds of downlink data transmission methods: single antenna transmission (that is, using a single antenna to transmit signals, which is a special case of MIMO system, which can only transmit single-layer data), transmit diversity (that is, in MIMO systems, using Diversity effect of time or/and frequency, transmit signal to improve signal reception quality, this method can only transmit single-layer data), open-loop space division multiplexing (that is, space division multiplexing that does not require user equipment to feedback channel state information ), closed-loop space-division multiplexing (that is, space-division multiplexing that requires user equipment to feed back channel state information), multi-user MIMO (that is, multiple users participate in the downlink communication of MIMO systems at the same frequency at the same time), closed-loop single-layer precoding (that is, use MIMO system, adopts precoding technology, only transmits single-layer data), beamforming transmission (that is, uses MIMO system, adopts beamforming technology, only transmits single-layer data).

When describing this embodiment, the following multi-antenna and multi-base station cooperation method is adopted: the serving base station of the user equipment and the cooperative base station only transmit single-layer data. Therefore, the optional downlink data transmission methods for the serving base station and the cooperative base station include: single-antenna transmission, transmit diversity, single-layer open-loop space division multiplexing, closed-loop single-layer precoding, single-layer multi-user MIMO, beamforming transmission Wait for 6 kinds. If different base stations transmit the same single-layer data, space diversity (also called macro diversity) between base stations is formed. If different base stations transmit different single-layer data, spatial multiplexing between base stations is formed. It should be pointed out that the above-mentioned multi-antenna and multi-base station cooperation method is just an example for illustrating the specific implementation of the present invention, and does not mean that the present invention requires the above restrictive conditions in the implementation process.

Fig. 4 shows a flowchart of a multi-antenna and multi-base station cooperation method in a downlink cellular system according to an embodiment of the present invention. As shown in Figure 4, the method according to the embodiment of the present invention includes the following steps:

Step 500: The judging unit 212 of the serving base station judges based on the information stored in the user equipment parameter storage 212 whether the user equipment enters the working mode of multi-antenna multi-base station cooperation.

Preferably, the serving base station determines whether the user equipment enters the working mode of multi-antenna multi-base station cooperation. The dependent factors include at least one of the geographical location of the user equipment, the path loss of the user equipment, and the downlink data buffer status of the user equipment. The information is stored in user equipment parameter storage 212 . However, it should be clear that the above parameters are still examples of the relevant parameters, and the present invention should not be limited to these parameters, and those skilled in the art can select any other appropriate parameters according to needs and future technological progress.

In this embodiment, in the multi-cell cellular system shown in FIG. 2 , for the base station 200, the user equipments are grouped according to the path loss values from the user equipments 400-414 to the base station 200, so that the user equipments 400-406 are the central user equipments ; Let user equipments 408-414 be boundary user equipments.

For the base station 202, the user equipments are grouped according to the path loss values from the user equipments 416-422 to the base station 202, so that the user equipments 418-422 are central user equipments; and the user equipment 416 is a border user equipment.

For base station 204, user equipments are grouped according to path loss values from user equipments 424-430 to base station 204, user equipments 424-426 are central user equipments; user equipments 428-430 are boundary user equipments. It should be pointed out that, according to the path loss value from the user equipment to the base station, the user equipment is divided into the central user equipment and the border user equipment, just to illustrate the selection of the appropriate user equipment to enter the multi-antenna multi-base station cooperation mode, which does not mean To determine that the user equipment enters the working mode of multi-antenna and multi-base station cooperation, the above grouping process must be performed.

Assuming that the serving base station enables all border user equipments to enter the working mode of multi-antenna and multi-base station cooperation, then, taking base station 202 as an example, user equipment 416 is in the working mode of multi-antenna and multi-base station cooperation. It should be pointed out that the above-mentioned user selection of multi-antenna multi-base station cooperation is only an example of switching the working mode of the user equipment, which does not mean that the implementation of the present invention requires the above restrictive conditions.

Assuming that the serving base station enables all boundary user equipments whose downlink data cache is larger than the threshold K to enter the multi-antenna multi-base station cooperation mode, then, taking the base station 202 as an example, if the judgment unit 212 judges that the downlink data cache of the user equipment 416 is larger than the threshold K, then The user equipment 416 is in the multi-antenna multi-base station cooperation mode. It should be pointed out that the above-mentioned user selection of multi-antenna multi-base station cooperation is only an example of switching the working mode of the user equipment, which does not mean that the implementation of the present invention requires the above restrictive conditions.

Step 505: The downlink control signaling sending unit 213 of the serving base station uses the downlink control signaling to send configuration information, so as to configure the user equipment.

Preferably, the configuration information of the downlink control signaling includes at least the cell number of the cooperative base station and the transmission mode of downlink data.

Preferably, the configuration information of the downlink control signaling at least includes: the cell number of the cooperative base station, and antenna configuration.

In this embodiment, four application examples are given.

Example 1: The configuration information of the downlink control signaling sent by the serving base station includes the cell number of the cooperative base station and the transmission mode of downlink data. The schematic diagram of its implementation is shown in FIG. 5 . In FIG. 5 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . It is assumed that the downlink data transmission mode of the cooperative base station 200 is transmit diversity; the downlink data transmission mode of the cooperative base station 204 is single-layer open-loop space division multiplexing. Then, the serving base station 202 sends the configuration information to the user equipment 416 through the downlink control signaling 600, including the cell numbers of the base station 200 and the base station 204, and the transmission mode of the downlink data of the base station 200 and the base station 204.

Example 2: The configuration information of the downlink control signaling sent by the serving base station includes the cell number of the cooperative base station, the transmission mode of the downlink data, and the antenna configuration. The schematic diagram of its implementation is shown in FIG. 6 . In FIG. 6 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the downlink data transmission mode of the cooperative base station 200 is closed-loop single-layer precoding, and the antenna configuration is 4 transmit antennas; the downlink data transmission mode of the cooperative base station 204 is beamforming transmission, and the antenna configuration is 4 transmit antennas. Therefore, the serving base station 202 sends the configuration information of the multi-antenna multi-base station method to the user equipment 416 through the downlink control signaling 620, including the cell numbers of the base station 200 and the base station 204, and the transmission mode of the downlink data of the base station 200 and the base station 204, There are also antenna configurations for base station 200 and base station 204 .

Example 3: The configuration information of the downlink control signaling sent by the serving base station includes the cell number of the cooperative base station and antenna configuration. The schematic diagram of its implementation is shown in FIG. 7 . In FIG. 7 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both of which are closed-loop single-layer precoding. Therefore, the user equipment 416 does not need to be notified of the transmission mode of the downlink data of the cooperative base station. In addition, the antennas of the cooperative base station 200 and the cooperative base station 204 are configured as four transmitting antennas. Then, the serving base station 202 sends the configuration information of the multi-antenna multi-base station method to the user equipment 416 through the downlink control signaling 640, including the cell numbers of the base station 200 and the base station 204, and the antenna configuration of the base station 200 and the base station 204.

Example 4: The configuration information of the downlink control signaling sent by the serving base station includes the cell number of the cooperative base station and antenna configuration. The schematic diagram of its implementation is shown in FIG. 8 . In FIG. 8 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both are single-layer multi-user MIMO, and the user equipments 416, 410, 430 constitute a multi-user Group. Therefore, the user equipment 416 does not need to be notified of the transmission mode of the downlink data of the cooperative base station. In addition, the antennas of the cooperative base station 200 and the cooperative base station 204 are configured as four transmitting antennas. Then, the serving base station 202 sends the configuration information of the multi-antenna multi-base station method to the user equipment 416 through the downlink control signaling 660, including the cell numbers of the base station 200 and the base station 204, and the antenna configuration of the base station 200 and the base station 204.

Examples 1 to 4 here are only examples of the configuration information of the downlink control signaling of the serving base station in the present invention, and do not mean that the configuration information of the downlink control signaling of the serving base station in the present invention is limited to examples 1 to 4 form.

Step 510: Based on the configuration of the serving base station, the user equipment obtains the system information of the serving base station and each cooperative base station, and the channel state information of the downlink channel required for resource allocation from the serving base station and the cooperative base station to the user equipment.

Preferably, the user equipment obtains the system information of the serving base station and each cooperative base station at least including antenna configuration.

Preferably, the user equipment obtains the system information of the serving base station and each cooperative base station and the channel state information of the downlink channel required for resource allocation. The user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, and the user equipment obtains the system information of the serving base station through each The broadcast channel of the cooperative base station obtains the system information of each cooperative base station.

Preferably, the user equipment obtains the system information and channel state information of the serving base station and each cooperative base station: the user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, and the user equipment obtains the system information of the serving base station through the configuration of the downlink control signaling in step 505 The information obtains the system information of each cooperative base station.

After obtaining the system information of the serving base station and each cooperative base station, the user equipment can detect the downlink reference signals of the serving base station and each cooperative base station, thereby obtaining channel state information of the serving base station and each cooperative base station.

In this embodiment, four application examples are given.

Example 1: The user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, including at least the antenna configuration, and the user equipment obtains the system information of each cooperative base station through the broadcast channel of each cooperative base station, including at least the antenna configuration. Then, the user equipment obtains the channel state information of the serving base station and each cooperative base station through the downlink reference signals of the serving base station and each cooperative base station, and its implementation diagram is shown in FIG. 5 . In FIG. 5 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . It is assumed that the downlink data transmission mode of the cooperative base station 200 is transmit diversity; the downlink data transmission mode of the cooperative base station 204 is single-layer open-loop space division multiplexing. Generally speaking, the user equipment 416 obtains the system information of the serving base station through the broadcast channel of the serving base station 202, including at least the antenna configuration of the base station 202 as four transmitting antennas, which is a necessary step in cellular communication and will not be further described here. In FIG. 5, the user equipment 416 obtains the system information of the base station 200 by receiving the broadcast channel of the base station 200 (shown as a dotted line 602), at least including the antenna configuration of the base station 200 as four transmitting antennas; by receiving the broadcast channel of the base station 204 ( Shown as a dotted line 604 ), the system information of the base station 204 is obtained, at least including the configuration of the antennas of the base station 204 as four transmitting antennas. Then, the user equipment 416 obtains the channel state information of the serving base station and each cooperative base station by detecting the downlink reference signals of the serving base station 202 and each cooperative base station 200 and base station 204 (shown as reference signal detection process 606 ).

Example 2: The user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, including at least the antenna configuration, and the user equipment obtains the system information of each cooperative base station through the configuration information of the downlink control signaling in step 505, including at least the antenna configuration. Then, the user equipment obtains the channel state information of the serving base station and each cooperative base station through the downlink reference signals of the serving base station and each cooperative base station, and its implementation diagram is shown in FIG. 6 . In FIG. 6 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the downlink data transmission mode of the cooperative base station 200 is closed-loop single-layer precoding, and the antenna configuration is 4 transmit antennas; the downlink data transmission mode of the cooperative base station 204 is beamforming transmission, and the antenna configuration is 4 transmit antennas. Generally speaking, the user equipment 416 obtains the system information of the serving base station through the broadcast channel of the serving base station 202, including at least the antenna configuration of the base station 202 as four transmitting antennas, which is a necessary step in cellular communication and will not be further described here. In FIG. 6, the user equipment 416 obtains the system information of the base station 200 and the base station 204 through the configuration information of the downlink control signaling in step 505 (in 620), at least including the antenna configuration of the base station 200 and the base station 204 as four transmitting antennas. Then, the user equipment 416 obtains the channel state information of the serving base station and each cooperative base station by detecting the downlink reference signals of the serving base station 202 and each cooperative base station 200 and base station 204 (shown as reference signal detection process 606 ).

Example 3: The user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, including at least the antenna configuration, and the user equipment obtains the system information of each cooperative base station through the configuration information of the downlink control signaling in step 505, including at least the antenna configuration. Then, the user equipment obtains the channel state information of the serving base station and each cooperative base station through the downlink reference signals of the serving base station and each cooperative base station, and its implementation diagram is shown in FIG. 7 . In FIG. 7 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both of which are closed-loop single-layer precoding. In addition, the antennas of the cooperative base station 200 and the cooperative base station 204 are configured as four transmitting antennas. Generally speaking, the user equipment 416 obtains the system information of the serving base station through the broadcast channel of the serving base station 202, including at least the antenna configuration of the base station 202 as four transmitting antennas, which is a necessary step in cellular communication and will not be further described here. In FIG. 7, the user equipment 416 obtains the system information of the base station 200 and the base station 204 through the configuration information of the downlink control signaling in step 505 (in 640), at least including the antenna configuration of the base station 200 and the base station 204 as four transmitting antennas. Then, the user equipment 416 obtains the channel state information of the serving base station and each cooperative base station by detecting the downlink reference signals of the serving base station 202 and each cooperative base station 200 and base station 204 (shown as reference signal detection process 606 ).

Example 4: The user equipment obtains the system information of the serving base station through the broadcast channel of the serving base station, including at least antenna configuration, and the user equipment obtains the system information of each cooperative base station through the configuration information of the downlink control signaling in step 505, including at least the antenna configuration. Then, the user equipment obtains the channel state information of the serving base station and each cooperative base station through the downlink reference signals of the serving base station and each cooperative base station, and its implementation diagram is shown in FIG. 8 . In FIG. 8 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both are single-layer multi-user MIMO, and the user equipments 416, 410, 430 constitute a multi-user Group. In addition, the antennas of the cooperative base station 200 and the cooperative base station 204 are configured as four transmitting antennas. Generally speaking, the user equipment 416 obtains the system information of the serving base station through the broadcast channel of the serving base station 202, including at least the antenna configuration of the base station 202 as four transmitting antennas, which is a necessary step in cellular communication and will not be further described here. In FIG. 7, the user equipment 416 obtains the system information of the base station 200 and the base station 204 through the configuration information of the downlink control signaling in step 505 (in 660), at least including the antenna configuration of the base station 200 and the base station 204 as four transmitting antennas. Then, the user equipment 416 obtains the channel state information of the downlink channel of the serving base station and each cooperative base station by detecting the downlink reference signals of the serving base station 202 and each cooperative base station 200 and base station 204 (shown as the reference signal detection process 606).

Examples 1 to 4 here are only embodiments of the present invention for the user equipment to obtain the system information and channel state information of the serving base station and each cooperative base station, and do not mean that the present invention is for the user equipment to obtain the system information of the serving base station and each cooperative base station Information and channel state information are only limited to the forms of Example 1 to Example 4.

Step 515: The user equipment feeds back the channel state information of the downlink channel required for resource allocation;

Preferably, the user equipment only feeds back the channel state information of the serving base station and each cooperative base station to the serving base station.

Preferably, the user equipment feeds back the channel state information of the serving base station and each cooperative base station to the serving base station and each cooperative base station respectively.

In this embodiment, four application examples are given.

Example 1: The user equipment only feeds back the channel state information of the downlink channels of the serving base station and each cooperative base station to the serving base station, and its implementation schematic diagram is shown in FIG. 5 . In FIG. 5 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . It is assumed that the downlink data transmission mode of the serving base station 202 is closed-loop single-layer precoding, the downlink data transmission mode of the cooperative base station 200 is transmit diversity; the downlink data transmission mode of the cooperative base station 204 is single-layer open-loop space division multiplexing. Since the downlink data transmission mode of the cooperative base station 200 and the cooperative base station 204 does not require the user to feed back the channel state information of the downlink channel. Therefore, the user equipment 416 only needs to send the channel state information of the serving base station 202 to the serving base station 202 (shown as a feedback process 700).

Example 2: The user equipment feeds back the channel state information of the downlink channel of the serving base station and each cooperative base station to the serving base station and each cooperative base station respectively, and its implementation diagram is shown in FIG. 6 . In FIG. 6 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the downlink data transmission mode of the serving base station 202 is transmit diversity, the downlink data transmission mode of the cooperative base station 200 is closed-loop single-layer precoding; the downlink data transmission mode of the cooperative base station 204 is beamforming transmission. Since the downlink data transmission mode of the serving base station 202 does not require the user to feed back the channel state information of the downlink channel. Therefore, the user equipment 416 needs to send the channel state information of the downlink channels of the cooperative base station 200 and the cooperative base station 204 to the cooperative base station 200 and the cooperative base station 204 respectively (shown as feedback processes 710 and 712 respectively).

Example 3: The user equipment feeds back the channel state information of the downlink channel of the serving base station and each cooperative base station to the serving base station and each cooperative base station respectively, and its implementation schematic diagram is shown in FIG. 7 . In FIG. 7 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both of which are closed-loop single-layer precoding. Since the downlink data transmission modes of the serving base station 202, the cooperative base station 200 and the cooperative base station 204 all require the user to feed back the channel state information of the downlink channel. Therefore, the user equipment 416 needs to send the channel state information of the downlink channels of the serving base station 202, the cooperative base station 200 and the cooperative base station 204 to the serving base station 202, the cooperative base station 200 and the cooperative base station 204 respectively (shown as feedback processes 720, 722 and 724 respectively). ).

Example 4: The user equipment only feeds back the channel state information of the downlink channels of the serving base station and each cooperative base station to the serving base station, and its implementation schematic diagram is shown in FIG. 8 . In FIG. 8 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both are single-layer multi-user MIMO, and the user equipments 416, 410, 430 constitute a multi-user Group. Since the downlink data transmission modes of the serving base station 202, the cooperative base station 200 and the cooperative base station 204 all require the user to feed back the channel state information of the downlink channel. Therefore, the user equipment 416 needs to send the channel state information of the downlink channels of the serving base station 202, the cooperative base station 200 and the cooperative base station 204 to the serving base station 202 (shown as a feedback process 730).

Examples 1 to 4 here are only embodiments of the present invention for the user equipment to feed back the channel state information of the downlink channels of the serving base station and each cooperative base station, and do not mean that the present invention feeds back the downlink channel information of the serving base station and each cooperative base station for the user equipment. The channel state information of the channel is only limited to the forms of Example 1 to Example 4.

Step 520: The resource scheduler 214 of the serving base station obtains the channel state information of the downlink channel from the serving base station and each cooperative base station to the user equipment, performs resource scheduling and background communication, and sends resource scheduling results and downlink communication data to the cooperative base station;

Preferably, the serving base station obtains the channel state information of the downlink channel required for resource allocation through feedback from the user equipment.

Preferably, each cooperative base station transmits the channel state information of the downlink channel required by the serving base station in resource allocation to the serving base station through the background.

Preferably, the background communication includes sending data from the serving base station to each cooperative base station, and the data includes at least resource scheduling results and downlink communication data.

In this embodiment, four application examples are given.

Example 1: The serving base station obtains the channel state information of the downlink channel required for resource allocation through feedback from the user equipment, and its implementation schematic diagram is shown in FIG. 5 . In FIG. 5 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . It is assumed that the downlink data transmission mode of the serving base station 202 is closed-loop single-layer precoding, the downlink data transmission mode of the cooperative base station 200 is transmit diversity; the downlink data transmission mode of the cooperative base station 204 is single-layer open-loop space division multiplexing. The user equipment 416 sends the channel state information of the downlink channel of the serving base station 202 to the serving base station 202 (feedback process 700). Then, the serving base station 202 obtains the channel state information of the downlink channel required for resource allocation through feedback from the user equipment. After the serving base station 202 completes the resource scheduling, the serving base station 202 at least sends the resource scheduling result and downlink communication data to the cooperative base station 200 and the cooperative base station 204 through background communication (X2 interfaces 300 and 304 ).

Example 2: each cooperative base station transmits the channel state information of the downlink channel required by the serving base station in resource allocation to the serving base station through the background, and its implementation diagram is shown in FIG. 6 . In FIG. 6 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the downlink data transmission mode of the serving base station 202 is transmit diversity, the downlink data transmission mode of the cooperative base station 200 is closed-loop single-layer precoding; the downlink data transmission mode of the cooperative base station 204 is beamforming transmission. The user equipment 416 needs to send the channel state information of the downlink channel of the cooperative base station 200 and the cooperative base station 204 to the cooperative base station 200 and the cooperative base station 204 respectively (feedback process 710 and 712 ). Then, the cooperative base station 200 and the cooperative base station 204 transmit the feedback information of the user equipment 416, that is, the channel state information of the downlink channel required by the serving base station 202 in resource allocation, to the serving base station 202 through the background (X2 interfaces 300 and 304). After the serving base station 202 completes the resource scheduling, the serving base station 202 at least sends the resource scheduling result and downlink communication data to the cooperative base station 200 and the cooperative base station 204 through background communication (X2 interfaces 300 and 304 ).

Example 3: Each cooperative base station transmits the channel state information of the downlink channel required by the serving base station in resource allocation to the serving base station through the background, and its implementation diagram is shown in FIG. 7 . In FIG. 7 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both of which are closed-loop single-layer precoding. The user equipment 416 needs to send the channel state information of the downlink channel of the serving base station 202, the cooperative base station 200 and the cooperative base station 204 to the serving base station 202, the cooperative base station 200 and the cooperative base station 204 respectively (feedback process 720, 722 and 724). Then, the cooperative base station 200 and the cooperative base station 204 transmit the feedback information of the user equipment 416, that is, the channel state information of the downlink channel required by the serving base station 202 in resource allocation, to the serving base station 202 through the background (X2 interfaces 300 and 304). After the serving base station 202 completes the resource scheduling, the serving base station 202 at least sends the resource scheduling result and downlink communication data to the cooperative base station 200 and the cooperative base station 204 through background communication (X2 interfaces 300 and 304 ).

Example 4: The serving base station obtains the channel state information of the downlink channel required for resource allocation through feedback from the user equipment, and its implementation schematic diagram is shown in FIG. 8 . In FIG. 8 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both are single-layer multi-user MIMO, and the user equipments 416, 410, 430 constitute a multi-user Group. The user equipment 416 needs to send the channel state information of the downlink channels of the serving base station 202, the cooperative base station 200 and the cooperative base station 204 to the serving base station 202 (feedback process 730). Then, the serving base station 202 obtains the channel state information of the downlink channel required for resource allocation through feedback from the user equipment. After the serving base station 202 completes the resource scheduling, the serving base station 202 at least sends the resource scheduling result and downlink communication data to the cooperative base station 200 and the cooperative base station 204 through background communication (X2 interfaces 300 and 304 ).

The examples 1 to 4 here are only embodiments of the present invention for the serving base station to obtain the channel state information of the downlink channel from the serving base station and each cooperative base station to the user equipment, and perform resource scheduling and background communication, and do not mean that the present invention is for the service The base station obtains the channel state information of the downlink channel from the serving base station and each cooperative base station to the user equipment, and performs resource scheduling and background communication only in the forms of examples 1 to 4.

Step 525: Send the allocation indication of the downlink resource from the allocation indication sending unit 215 of the serving base station or the cooperative base station to the user equipment through the downlink air interface;

Preferably, the serving base station sends a downlink resource allocation indication to the user equipment, and the allocation indication includes at least the frequency position of the downlink resource and precoding information required for the serving base station to send data.

Preferably, the serving base station sends an allocation indication of downlink resources to the user equipment, and the allocation indication includes at least the frequency position of the downlink resource, the precoding information required for the serving base station to transmit data, and the precoding information required for each cooperative base station to transmit data. information.

Preferably, the serving base station and each cooperative base station respectively send downlink resource allocation instructions to the user equipment, and the allocation instructions include at least frequency positions of downlink resources and precoding information required for the base station to send data.

In this embodiment, four application examples are given.

Example 1: The serving base station sends a downlink resource allocation instruction to the user equipment. The allocation instruction includes at least the frequency position of the downlink resource and the precoding information required for the serving base station to send data. The schematic diagram of its implementation is shown in FIG. 5 . In FIG. 5 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assuming that the transmission mode of the downlink data of the serving base station 202 is closed-loop single-layer precoding, the transmission mode of the downlink data of the cooperative base station 200 is transmit diversity; the transmission mode of the downlink data of the cooperative base station 204 is single-layer open-loop space division multiplexing, In addition, the serving base station and the cooperative base station transmit the same single-layer data, forming space diversity among the base stations. It is easy to know that the role of the cooperative base station here is to help improve the reception quality of the signal transmitted by the serving base station, so the cooperative base station does not have precoding information for sending data. Then, the serving base station 202 sends an indication of allocation of downlink resources to the user equipment 416 (instruction 608 ), including the frequency position of the downlink resource and the precoding information required for the serving base station 202 to send data.

Example 2: The serving base station and each cooperative base station respectively send downlink resource allocation instructions to the user equipment, and the allocation instructions include at least the frequency position of the downlink resource and precoding information required for the base station to send data. Its implementation diagram is shown in Figure 6. In FIG. 6 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the downlink data transmission mode of the serving base station 202 is transmit diversity, the transmission mode of the downlink data of the cooperative base station 200 is closed-loop single-layer precoding; the transmission mode of the downlink data of the cooperative base station 204 is beamforming transmission, and the serving base station and the cooperative base station The same single-layer data is transmitted to form space diversity among base stations. It is easy to know that the cooperative base station has precoding information for sending data. Then, the serving base station 202, the cooperative base station 200 and the cooperative base station 204 respectively send downlink resource allocation indications (indication 624, indication 628 and indication 626) to the user equipment 416, including the frequency position of the downlink resource, the data sent by the base stations 200, 202 and 204 The required precoding information.

Example 3: The serving base station sends a downlink resource allocation instruction to the user equipment, and the allocation instruction includes at least the frequency position of the downlink resource, the precoding information required for the serving base station to send data, and the precoding information required for each cooperative base station to send data information. Its implementation diagram is shown in Figure 7. In FIG. 7 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assuming that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both are closed-loop single-layer precoding, and the serving base station and the cooperative base station transmit different single-layer data, Spatial multiplexing between base stations is formed. It is easy to know that both the serving base station and the cooperative base station have precoding information for sending data. Therefore, the serving base station 202 sends an indication of allocation of downlink resources to the user equipment 416 (instruction 644), including the frequency position of the downlink resource, the precoding information required for the serving base station 202 to send data, and the required time for the cooperative base station 200 and cooperative base station 204 to send data. precoding information.

Example 4: The serving base station sends a downlink resource allocation instruction to the user equipment, and the allocation instruction includes at least the frequency position of the downlink resource, the precoding information required for the serving base station to send data, and the precoding information required for each cooperative base station to send data information, and its implementation diagram is shown in Figure 8. In FIG. 8 , the serving base station of user equipment 416 is base station 202 , and its cooperative base stations are base station 200 and base station 204 . Assume that the transmission mode of the downlink data of the cooperative base station 200 and the cooperative base station 204 is the same as the transmission mode of the downlink data of the serving base station 202 by default, both are single-layer multi-user MIMO, and the user equipments 416, 410, 430 constitute a multi-user Group. For the same user, its serving base station and cooperative base station transmit the same single-layer data, forming space diversity between base stations. It is easy to know that both the serving base station and the cooperative base station have precoding information for sending data. Therefore, the serving base station 202 sends an indication of allocation of downlink resources to the user equipment 416 (instruction 664), including the frequency position of the downlink resource, the precoding information required for the serving base station 202 to send data, and the required time for the cooperative base station 200 and cooperative base station 204 to send data. the precoding information; the serving base station 200 sends to the user equipment 410 a downlink resource allocation instruction (indication 668), including the frequency position of the downlink resource, the precoding information required for the serving base station 200 to send data, and the cooperative base station 202 and the cooperative base station 204 send The precoding information required for the data; the serving base station 204 sends an indication of downlink resource allocation (instruction 666) to the user equipment 430, including the frequency position of the downlink resource, the precoding information required for the serving base station 204 to send data, the cooperative base station 200 and the cooperative base station The base station 202 transmits precoding information required for data.

Examples 1 to 4 here are only embodiments of the present invention for the user equipment to obtain the allocation instruction of the downlink resource, which does not mean that the present invention is limited to the form of the present invention for the user equipment to obtain the allocation instruction of the downlink resource.

So far the invention has been described with reference to the preferred embodiments. It should be understood that various other changes, substitutions and additions can be made by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention is not limited to the specific embodiments described above, but should be defined by the appended claims.

Claims (5)

1. A serving base station communicating with a mobile station, the serving base station comprising: a transmitter configured to send a downlink reference signal and a downlink control signal from the serving base station to the mobile station, Wherein, the downlink control signal includes: cell identity information of other base stations except the serving base station, and information indicating the number of antenna ports at the other base stations except the serving base station, the The downlink control signal is a dedicated signal of the mobile station. 2. The serving base station according to claim 1, further comprising: A receiver configured to receive channel state information related to the serving base station generated by the mobile station using the cell identity information, the information representing the number of antenna ports, and the downlink reference signal. 3. A mobile station in communication with a serving base station, the mobile station comprising: a receiver configured to receive, at the mobile station, a downlink reference signal and a downlink control signal from the serving base station, Wherein, the downlink control signal includes: cell identity information of other base stations except the serving base station, and information indicating the number of antenna ports at the other base stations except the serving base station, the The downlink control signal is a dedicated signal of the mobile station. 4. The mobile station of claim 3, further comprising: a generator configured to use the cell identity information, the information representing the number of antenna ports, and the downlink reference signal to generate channel state information related to the serving base station, A transmitter configured to send the channel state information to the serving base station. 5. A communication method for a serving base station communicating with a mobile station, the communication method comprising: sending a downlink reference signal and a downlink control signal from the serving base station to the mobile station, Wherein, the downlink control signal includes: cell identity information of other base stations except the serving base station, and information indicating the number of antenna ports at the other base stations except the serving base station, the The downlink control signal is a dedicated signal of the mobile station.

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