WO2011082571A1 - Method and base station for allocating layers - Google Patents

Abstract

The present invention provides a dual-layer allocation method, and the method includes: dividing the total layers of current transmission into some groups, wherein, each group corresponds to one or two layers, and the layer corresponding to each group is different from each other; allocating a group corresponding to two layers in said some groups to a target user, when the target user data is transmitted on two layers. The present invention also provides a base station. The present invention enables the dual-layer transmission for one user at multi-user transmission, and by the allocation restriction on dual-layer users, signaling overhead can be optimized greatly on the premise of guaranteeing the system performance.

Description

 Layer allocation method and base station

TECHNICAL FIELD The present invention relates to the field of mobile communications, and in particular, to a layer allocation method and a base station.

Background technique

In wireless communication, if multiple antennas are used at the transmitting end (such as an evolved base station (eNB)), spatial multiplexing may be used to increase the transmission rate, that is, different antenna positions on the same time-frequency resource at the transmitting end. Different data is transmitted, and multiple antennas are also used at the receiving end (UE). All antenna resources can be allocated to the same user in the case of a single user. This transmission form is called SU-MIMO (single-user multiple-input multiple-output). . In addition, resources of different antenna spaces can be allocated to different users in the case of multiple users. This transmission form is called MU-MIMO (Multi-User MIMO). If the transmission system is to support both single-user MIMO and multi-user MIMO, it is necessary for the eNB to provide the UE with data in both transmission modes with control signaling. The UE needs to know the rank (Rank) used by the eNB for the UE transmission in both transmission modes. In the single-user mode, since all antenna resources are allocated to the same user, the number of layers used for transmission is equal to the eNB in the transmission. The rank used, and in multi-user transmission, the number of layers used for one user transmission is less than the total number of layers of the transmission. To achieve dynamic switching between single-user and multi-user transmissions, the eNB needs to inform the UE of different data in different transmission modes. In addition, in the version number 10 of LTE (Long Term Evolution), the transmission mode of the MIMO has been determined by using a Demodulation Reference Signal (DMRS) for demodulation. The location of the pilot is obtained so that the channel and interference estimates can be made on the pilot. The total number of layers of different transmissions has different pilot patterns. For example, in LTE version number 10, there are initially three different patterns (DMRS Pattern). When the total number of layers or rank is 1 to 2, A pattern (DMRS pattern 1 ), as shown in Figure 1 (a), uses a second pattern (DMRS pattern 2 ) when the total number of layers or rank is 3 to 4, as shown in Figure 1 (b) The third pattern (DMRS pattern 3) is used when the total number of layers or rank is 5 to 8, as shown in Figure 1 (c). In single-user transmission, all the data of the transport layer are given to the same UE. Therefore, the UE can know the pilot pattern as long as the rank is acquired, and the location of the pilot can also be known. In multi-user transmission, the UE needs to know which layer and the layer to transmit to the UE. The base station needs to allocate corresponding layer indication information to different UEs. The layer mentioned here may also be called an antenna port, and the allocation layer is equivalent to Distribution of antenna ports. In the existing version number 8 technology, there is no such requirement.

SUMMARY OF THE INVENTION As mentioned above, version number 10 of LTE requires a new layer allocation method to support DMRS-based MIMO multi-user transmission. In addition, limited to transmission performance, when a multi-user transmits, one user allocates at most two layers of resources; when the total number of layers or ranks transmitted is greater than 2, there is currently no way to allocate two layers to the target user. The technical problem to be solved by the present invention is to provide a layer allocation method and a base station, which provide the possibility of two-layer transmission of a user in multi-user transmission. In order to solve the above problem, the present invention provides a layer allocation method, including: dividing the total number of layers currently transmitted into several groups, each group corresponding to one layer or two layers, and corresponding layers of each group are different from each other, when the target user When the data is transmitted on two layers, a group of the corresponding two layers in the plurality of groups is allocated to the target user. Preferably, the foregoing method may further have the following feature: when data of the target user is transmitted on two layers, the user-specific reference signals corresponding to the two layers are transmitted in the same physical resource by using code division multiplexing; Alternatively, the user-specific reference signals corresponding to the two layers are transmitted in different frequency divisions by using frequency division multiplexing. Preferably, the above method may further have the following characteristics: the index values corresponding to the two layers in the two-layer group are respectively n and n+1, where n is an even number; or, m and m+2, m is 0. , 1, 4,

Preferably, the foregoing method may further have the following characteristics: when the total number of layers transmitted is 3, the index values of the two layers corresponding to the two layers are 0 and 1; or, 0 and 2. Preferably, the foregoing method may further have the following feature: when the total number of layers transmitted is 4 or 5, or the pilot pattern is the second pattern, the index values of the two layers corresponding to the two layers are 0. And 1, 2 and 3; or, 0 and 2, 1 and 3. Preferably, the foregoing method may further have the following characteristics: when the total number of layers transmitted is 6 or 7, the index values of the two layers corresponding to the two layers correspond to 0, 1, 2, and 3, 4, and 5, Or, 0 and 1, 2 and 3, 4 and 6; or, 0 and 2, 1 and 3, 4 and 6, or, 0 and 2, 1 and 3, 4 and 5. Preferably, the above method may also have the following features: when the total number of layers transmitted is 8, or the pilot pattern is the third pattern, the index values of the two layers corresponding to the two layers are 0 and 1 respectively. , 2 and 3, 4 and 5, 6 and 7, or, 0 and 1, 2 and 3, 4 and 6, 5 and 7; or, 0 and 2, 1 and 3, 4 and 6, 5 and 7, or , 0 and 2, 1 and 3, 4 and 5, 6 and 7. The present invention further provides a base station, where the base station is configured to divide the total number of layers currently transmitted into several groups, each group corresponding to one layer or two layers, and corresponding layers of each group are different from each other, when the data of the target user is in two When transmitting on the layer, a group of the corresponding two layers in the plurality of groups is allocated to the target user. Preferably, the foregoing base station may further have the following features: the base station is configured to: when the data of the target user is transmitted on two layers, transmit the two layers corresponding to the same physical resource by using code division multiplexing User-specific reference signals; or, frequency-multiplexed transmission of the two-layer corresponding user-specific reference signals on different physical resources. Preferably, the foregoing base station may further have the following features, the base station is configured to: divide each group according to the following manner: the index values corresponding to the two layers in the group corresponding to the two layers are respectively n and n+1, or m And m+2, where n is an even number and m is 0, 1, 4, 5. Preferably, the foregoing base station may further have the following features: the base station is configured to: divide each group as follows: When the total number of layers to be transmitted is 3, the index corresponding to the two layers of the two-layer group is 0 and 1; or, 0 and 2. Preferably, the foregoing base station may further have the following features, the base station is configured to: divide each group as follows: when the total number of layers to be transmitted is 4 or 5, or when the pilot pattern is the second pattern, corresponding to two The index values of the two layers in each layer of the layer are 0 and 1; 2 and 3; or 0 and 2, 1 and 3. Preferably, the foregoing base station may further have the following features, the base station is configured to: divide each group as follows: When the total number of layers transmitted is 6 or 7, the index values of the two layers corresponding to the two layers correspond to 0 and 1, 2 and 3, 4 and 5, or, 0 and 1, 2 and 3, 4 And 6; or, 0 and 2, 1 and 3, 4 and 6, or, 0 and 2, 1 and 3, 4 and 5. Preferably, the foregoing base station may further have the following features, the base station is configured to: divide each group as follows: when the total number of layers to be transmitted is 8, or the pilot pattern is the third pattern, corresponding to the two layers The index values of the two layers in each group are 0 and 1, 2 and 3, 4 and 5, 6 and 7, or 0 and 1, 2 and 3, 4 and 6, 5 and 7, or 0 and 2 , 1 and 3, 4 and 6, 5 and 7, or, 0 and 2, 1 and 3, 4 and 5, 6 and 7. The present invention provides a two-layer allocation method and a base station, which provides the possibility of two-layer transmission of a user in multi-user transmission, and optimizes signaling by ensuring system performance by limiting the allocation of two-layer users. s expenses.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: Figure 1 (a) is the total number of layers transmitted or the pilot pattern when the rank is 1 to 2; Figure 1 (b) is the total number of layers transmitted or the pilot pattern when the rank is 3 to 4. Figure 1 (c) is the pilot pattern when the total number of layers transmitted or rank is 5 to 8.

The preferred embodiment of the present invention contemplates the problem that the demodulation pilot based MIMO multi-user transmission is not supported in the LTE version number 10 in the related art, and the present invention provides a two-layer allocation method, which provides The possibility of a user's two-layer transmission during multi-user transmission, through the limitation of the distribution layer, maximizes the signaling overhead while ensuring system performance.

4, the pilot pattern corresponding to one layer and two layers is the first pilot pattern, and the three layers and four layers correspond to The pilot pattern is a second pilot pattern, and the pilot patterns of the five, six, seven, and eight layers are the third pilot patterns. The two-layer allocation method provided by the present invention includes: the total number of layers or ranks of the current transmission is M, and M is divided into k groups, each group corresponding to one layer or two layers, and corresponding layers of each group are different from each other, when the target user When the data is transmitted on two layers, a group of the corresponding two layers in the k group is allocated to the target user, and the data of the target user is transmitted on the two layers corresponding to the allocated group. Further, when the data of the target user is transmitted on two layers, the two-layer corresponding user-specific reference signals are transmitted on the same physical resource by using code division multiplexing. Further, the data is data carried by a physical downlink shared channel (PDSCH). Further, the index corresponding to the two layers of the two-layer group is n and n+1, where n is an even number. Further, when the total number of layers (rank) of the transmission is 3, the index corresponding to the two layers of the two layers corresponds to 0 and 1. Further, when the total number of layers (rank) of the transmission is 4, or the pilot pattern is the second pattern, the index values of the two layers corresponding to the two layers correspond to 0 and 1, 2 and 3. Further, when the total number of layers (rank) of the transmission is 5, the index values of the two layers corresponding to the two layers correspond to 0 and 1, 2 and 3. Further, when the total number of layers (rank) is 6 or 7, the index corresponding to the two layers of the two layers corresponds to 0 and 1, 2 and 3, 4 and 5, or two The index of the two layers of the layer corresponds to 0 and 1, or 2 and 3, or 4 and 6; further, when the total number of layers (rank) is 8, or the pilot pattern is In the case of the third pattern, the index corresponding to the two layers of the two layers corresponds to 0 and 1, 2 and 3, 4 and 5, 6 and 7, or two layers corresponding to the two layers corresponding to the two layers. Index values are 0 and 1, 2 and 3, 4 and 6, 5 and 7; Further, when the data of the target user is transmitted on two layers, the user-specific reference signals corresponding to the two layers are transmitted in different frequency divisions by using frequency division multiplexing.

Further, the index corresponding to the two layers of the two-layer group is m and m+2 , and m is 0, 1, 4, 5. Further, when the total number of layers (rank) of the transmission is 3, the index values of the two layers are 0 and 2; further, the total number of layers (rank) is 4, or the pilot pattern When the second pattern is used, the index corresponding to the two layers of the two layers corresponds to 0 and 2, 1 and 3; further, when the total number of layers (rank) is 5, corresponding to two The index values of the two layers of the layer correspond to 0 and 2, 1 and 3; further, when the total number of layers (rank) is 6 or 7, the two layers corresponding to the two layers correspond to the two layers. The index values are 0 and 2, 1 and 3, 4 and 6, or, the two groups corresponding to the two layers have corresponding index values of 0 and 2, 1 and 3, 4 and 5; further, the total transmission When the number of layers (rank) is 8, or when the pilot pattern is the third pattern, the index values of the two layers corresponding to the two layers are 0 and 2, 1 and 3, 4 and 6, 5 and 7. Or, the two groups corresponding to the two layers have index values corresponding to 0 and 2, 1 and 3, 4 and 5, 6 and 7. The layer index corresponds to an antenna port; for example, layer index 0 to layer index 7 corresponds to antenna port 7 to antenna port 13. When the user's data is transmitted on two layers, the two layers are a group including two layers in the above-mentioned packet, that is, the two layers are a combination of layer indexes given in the following method.

Method 1 When a user's data is transmitted on two layers, the two layers of corresponding UE-specific reference signals are code-multiplexed on the same physical resource. Mode transfer.

The index corresponding to the two layers is n and n+1, where n is an even number. When the total number of layers (rank) of the transmission is 3, the index values of the two layers are 0 and 1; when the total number of layers (rank) is 4 or 5, or the pilot pattern is the second pattern The index values of the two layers are 0 and 1, 2 and 3; when the total number of layers (rank) is 6 or 7, the index values of the two layers are 0 and 1, 2 and 3, 4, and 5; when the total number of layers (rank) is 8, or the pilot pattern is the third pattern, the index values of the two layers are 0 and 1, 2, and 3, 4 and 5, 6 and 7.

 Method 3 When the total number of layers (rank) of the transmission is 3, the index values of the two layers are 0 and 1; when the total number of layers (rank) is 4 or 5, or the pilot pattern is the second For the pattern, the index values of the two layers are 0 and 1, 2 and 3; when the total number of layers (rank) is 6 or 7, the index values of the two layers are 0 and 1, 2 and 3, 4 and 6; when the total number of layers (rank) is 8, or the pilot pattern is the third pattern, the index values of the two layers are 0 and 1, 2 and 3, 4 and 6, 5 and 7.

Method 4 When a user's data is transmitted on two layers, the user-specific reference signals corresponding to the two layers are transmitted in different frequency divisions by using frequency division multiplexing. The index corresponding to the two layers in the method 5 is m and m+2, where m can be 0, 1, 4, 5. When the total number of layers (rank) is 3, the index values of the two layers are 0 and 2; when the total number of layers (rank) is 4 or 5, or the pilot pattern is the second pattern The two layers correspond to index values of 0 and 2, 1 and 3; when the total number of layers (rank) is 6 or 7, the index values of the two layers are 0 and 2, 1 and 3, 4, and 6; when the total number of layers (rank) is 8, or the pilot pattern is the third pattern, the index values of the two layers are 0 and 2, 1 and 3, 4, and 6 , 5 and 7.

 Method 6 When the total number of layers (rank) of the transmission is 3, the index values of the two layers are 0 and 2; when the total number of layers (rank) is 4 or 5, or the pilot pattern is the second For the pattern, the two layers have corresponding index values of 0 and 2, 1 and 3; when the total number of layers (rank) is 6 or 7, the index values of the two layers are 0 and 2, 1 and 3, 4 and 5; when the total number of layers (rank) is 8, or the pilot pattern is the third pattern, the index values of the two layers are 0 and 2, 1 and 3, 4 And 5, 6 and 7.

It should be noted that the multi-user spatial multiplexing may be limited to the M layer. For example, if M=4, the above-mentioned grouping situation larger than the M layer does not exist, but only applies to the case where the M layer is less than or equal to. It should be noted that the features in the embodiments and the embodiments in the present application may be combined with each other without conflict.

The present invention also provides a base station, which is configured to divide a total number of layers currently transmitted. For each group, each group corresponds to one layer or two layers, and the corresponding layers of each group are different from each other. When the data of the target user is transmitted on two layers, a group corresponding to the two layers of the several groups is allocated to the target. user. The base station is configured to transmit the two-layer corresponding user-specific reference signals on the same physical resource when the data of the target user is transmitted on two layers; or, in different physical The resource-specific frequency-multiplexed mode transmits the two-layer corresponding user-specific reference signals. For details on how to divide each group into groups, refer to the method examples, and no further details are provided here.

The present invention provides the possibility of two-layer transmission of a user in multi-user transmission. By the above limitation on the allocation layer, the signaling overhead is optimized to the greatest extent under the premise of ensuring system performance.

One of ordinary skill in the art will appreciate that all or a portion of the steps above may be accomplished by a program to instruct the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software. While the invention has been described in connection with the specific embodiments, the modifications and variations may be Such modifications and variations are considered to be within the scope of the invention and the scope of the appended claims.

INDUSTRIAL APPLICABILITY The present invention provides a layer allocation method and a base station, and provides a technical solution for realizing a two-layer transmission of a user when transmitting by multiple users. By limiting the allocation of two layers of users, the maximum optimization is performed under the premise of ensuring system performance. The overhead of signaling.

Claims

Claim  A layer allocation method, comprising: dividing a total number of layers currently transmitted into a plurality of groups, each group corresponding to one layer or two layers, and corresponding layers of each group are different from each other, and data of the target user is transmitted on two layers. At the time, a group of the corresponding two layers of the plurality of groups is allocated to the target user. 2. The method according to claim 1, wherein: when the data of the target user is transmitted on two layers, the user-specific reference signals corresponding to the two layers are code-multiplexed on the same physical resource. Or, the user-specific reference signals corresponding to the two layers are transmitted in different frequency divisions by using frequency division multiplexing.  3. The method according to claim 1, wherein: the index values corresponding to the two layers in the group corresponding to the two layers are respectively n and n+1, wherein n is an even number; or, respectively, m and m+2, m It is 0, 1, 4, 5. 4. The method according to claim 1, wherein: when the total number of layers transmitted is 3, the index values corresponding to the two layers in the group corresponding to the two layers are 0 and 1 respectively; or 0 and 2, respectively. 5. The method according to claim 1, wherein: when the total number of layers transmitted is 4 or 5, or the pilot pattern is the second pattern, the group corresponding to the two layers is two groups, and the two groups are The corresponding index values of the two layers are 0 and 1, 2 and 3, respectively; or 0 and 2, 1 and 3, respectively. 6. The method according to claim 1, wherein: when the total number of layers transmitted is 6 or 7, the group corresponding to the two layers is three groups, and the index values corresponding to the two layers in the three groups are 0 and 1 respectively. , 2 and 3, 4 and 5, or 0 and 1, 2 and 3, 4 and 6, respectively; or 0, 2 and 1 and 3, 4 and 6, respectively, or 0 and 2, 1 respectively And 3, 4 and 5. 7. The method of claim 1 wherein: When the total number of layers transmitted is 8, or the pilot pattern is the third pattern, the group corresponding to the two layers is four groups, and the index values corresponding to the two layers in the four groups are 0 and 1, 2, and 3, respectively. , 4 and 5, 6 and 7, or 0 and 1, 2 and 3, 4 and 6, 5 and 7 respectively; or 0 and 2, 1 and 3, 4 and 6, 5 and 7, respectively, or They are 0 and 2, 1 and 3, 4 and 5, 6 and 7. A base station, wherein the base station is configured to divide the total number of layers currently transmitted into several groups, each group corresponding to one layer or two layers, and corresponding layers of each group are different from each other, when the data of the target user is on two layers. At the time of transmission, a group of the corresponding two layers of the plurality of groups is assigned to the target user. 9. The base station according to claim 8, wherein: the base station is configured to: when the data of the target user is transmitted on two layers, transmit the two layers by using code division multiplexing on the same physical resource. Corresponding user-specific reference signals; or, frequency-multiplexed transmission of the two-layer corresponding user-specific reference signals on different physical resources. The base station according to claim 8, wherein: the base station is configured to: divide each group according to the following manner: the index values corresponding to two layers in the group corresponding to the two layers are respectively n and n+1, or respectively , m and m+2, where n is an even number and m is 0, 1, 4, 5. The base station according to claim 8, wherein: the base station is configured to: divide each group as follows: when the total number of layers to be transmitted is 3, the index values corresponding to the two layers in the group corresponding to the two layers are respectively 0 and 1; or 0, 2, respectively. 12. The base station according to claim 8, wherein: the base station is configured to: divide each group as follows: when the total number of layers transmitted is 4 or 5, or the pilot pattern is the second pattern, The two groups corresponding to the two layers are two groups, and the index values corresponding to the two layers in the two groups are 0 and 1 respectively; 2 and 3; or 0 and 2, 1 and 3, respectively. The base station according to claim 8, wherein: the base station is configured to: divide each group as follows: when the total number of layers to be transmitted is 6 or 7, the group corresponding to the two layers is three groups, Two pairs of three groups The index values should be 0 and 1, 2 and 3, 4 and 5, respectively, or 0 and 1, 2 and 3, 4 and 6; or 0 and 2, 1 and 3, 4 and 6, respectively. Or 0, 2, 1, and 3, 4, and 5, respectively. 14. The base station according to claim 8, wherein: the base station is configured to: divide each group as follows: when the total number of layers transmitted is 8, or the pilot pattern is the third pattern, corresponding to two The group of layers is four groups, and the index values of the two layers in the four groups are 0 and 1, 2 and 3, 4 and 5, 6 and 7, respectively, or 0 and 1, 2 and 3, 4 and respectively. 6, 5 and 7, or 0 and 2, 1 and 3, 4 and 6, 5 and 7, respectively, or 0 and 2, 1 and 3, 4 and 5, 6 and 7.