Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The following describes in detail a method, an apparatus, and a system for implementing multi-user MIMO in a CoMP scenario according to an embodiment of the present invention with reference to the accompanying drawings.
The first embodiment is as follows:
as shown in fig. 1, the method for implementing multi-user MIMO in a CoMP scenario according to an embodiment of the present invention includes the following steps:
101. receiving a Preferred Matrix Index (PMI) reported by at least two User terminals (UE).
The base station receives PMIs reported by at least two UEs, wherein the PMIs are used for quantizing the channel space among multiple channels in MIMO.
102. And performing multi-user MIMO pairing on the at least two user terminals according to the preferred matrix index.
The pairing here refers to selecting at least two users, so that the data multiplexing of the users is sent on the same time-frequency resource block, and when performing MU-MIMO pairing on a plurality of user terminals, there can be a plurality of pairing algorithms, such as MU-MIMO pairing according to parameters such as maximized throughput, maximized signal-to-noise ratio, PMI orthogonal pairing, and the like; the present embodiment adopts a PMI orthogonal pairing algorithm, but the present invention is not limited to this pairing algorithm.
103. And sending the PMI of the paired user terminal of the user terminal to the current user terminal.
After the PMI is issued, the current user terminal can acquire the full codebook information corresponding to the user terminal, namely all codebook information during coding.
For convenience of description, one user of the at least two user terminals calls a current user;
104. and overlapping the data coded by the at least two user terminals and then sending out the data.
In the embodiment of the present invention, the numbers of the above steps are not used to limit the execution order, for example, steps 103 and 104 may be executed simultaneously.
In order to better perform the method for implementing multi-user MIMO in the CoMP scenario, an embodiment of the present invention further provides a base station for implementing multi-user MIMO in the CoMP scenario, as shown in fig. 2, including a receiving unit 21, a pairing unit 22, a first sending unit 23, and a second sending unit 24; wherein,
a receiving unit 21, configured to receive preferred matrix indexes reported by at least two user terminals;
a pairing unit 22, configured to perform multi-user MIMO pairing on the at least two user terminals according to the preferred matrix index;
a first sending unit 23, configured to issue, to a current user terminal, a preferred matrix index of a paired user terminal of the user terminal;
and a second sending unit 24, configured to send out the encoded data of the at least two user terminals after superimposing.
According to the method and the base station for realizing multi-user MIMO in the CoMP scene, provided by the embodiment of the invention, the optimal matrix index of the paired user terminal of the user terminal is provided for the current user terminal, so that the current user terminal can acquire the full codebook information used in pre-coding before signal transmission, and the current user terminal can analyze the received superposed signals according to the full codebook information, thereby inhibiting the paired user interference between MU-MIMO users.
Example two:
as shown in fig. 3, the method for implementing multi-user MIMO in a CoMP scenario according to an embodiment of the present invention includes the following steps:
301. and reporting the Preferred Matrix Index (PMI) of the current user terminal (UE) to a base station.
The PMIs referred to in this embodiment are all measured under the condition that the UE performs precoding in the Rank-1 mode.
302. And receiving a preferred matrix index of a paired user terminal of the current user terminal, which is issued by the base station, wherein the paired user terminal is selected by the base station according to the preferred matrix index reported by the current user terminal.
303. And receiving the superposed signal sent by the base station, and analyzing the superposed signal by combining the preferred matrix index of the current user terminal and the paired user terminal thereof.
The parsing here can use the detection algorithm of the existing receiver.
In the embodiment of the present invention, the numbers of the above steps are not used to limit the execution sequence, and the specific execution sequence may be determined according to specific situations.
At this time, the PMIs of the current UE and the paired UE are combined to obtain the full codebook information used by the base station for signal precoding, and then the received superposed signals are analyzed according to the obtained full codebook information, so that the signals required to be received by the current UE can be more accurately obtained, and the paired user interference existing between MU-MIMO users is inhibited.
In order to better implement the method for implementing multi-user MIMO in the CoMP scenario, an embodiment of the present invention further provides a user terminal for implementing multi-user MIMO in the CoMP scenario, as shown in fig. 4, including a reporting unit 41, a receiving unit 42, and an analyzing unit 43; wherein,
a reporting unit 41, configured to report an optimal matrix index of a current user terminal to a base station;
a receiving unit 42, configured to receive a preferred matrix index of a paired user terminal of a current user terminal issued by the base station, and receive a superimposed signal sent by the base station, where the paired user is selected by the base station according to the preferred matrix index reported by the current user terminal;
and an analyzing unit 43, configured to analyze the superimposed signal in combination with the preference matrix index of the current user terminal and the paired user terminal thereof.
According to the method for realizing multi-user MIMO in the CoMP scene and the user terminal, the preferred matrix index of the user terminal matched with the user terminal is firstly obtained, and then the preferred matrix index of the user terminal is combined to obtain the full codebook information used for pre-coding before signal transmission, so that the current user terminal can analyze the received superposed signals according to the full codebook information, and the interference of matched users existing between MU-MIMO users is restrained.
Example three:
in this embodiment, first, the implementation scenario of the present invention is set as follows: there are 2 cells cooperating to form CoMP, and the base station of each cell configures 2 antennas, and antennas in the cell are irrelevant to antennas between cells; in this case, since CoMP is configured by 2 cells, the network side has a total of 4 antennas (i.e., N)tx4) joint transmission. For the user terminal, there are at least 2 users in the CoMP zone, and each user has at least 2 transmitting antennas.
After CoMP is established, a user in the CoMP area knows that the site is in the CoMP mode, that is, knows that the cell and the cooperative cell jointly send data to a User Equipment (UE).
Taking the MU-MIMO pairing of a plurality of user terminals according to PMI as an example, and with reference to fig. 5, the method for implementing multi-user MIMO in a CoMP scenario provided in the embodiment of the present invention specifically includes the following steps:
501. the base station informs the UE to feed back the subband-based PMI adopting a RANK-1 mode through high-layer signaling.
Compared with the information about the channel carried by the common full-bandwidth-based PMI, the subband-based PMI is more accurate and can be better matched with the channel.
502. And the UE starts the sub-band PMI measurement in a RANK-1 mode according to the high-level signaling instruction issued by the base station.
The algorithm for determining PMI in RANK-1 mode is
Wherein, CiFor the codebook given in the LTE protocol RANK 1, is one NtxX 1 column vector, where i has a value in the range of [0, 15%]The whole number of (1); h is channel information, which can be estimated by common pilot, and is a 2 × 4 (number of receiving antennas × number of transmitting antennas) matrix;
specifically, each CiSequentially substituted into the formula [ Ci HHH*H*Ci]In and find the formula [ Ci HHH*H*Ci]C corresponding to maximum valueiCodebook C at this timeiThe corresponding number i is the PMI of the current UE。
503. The UE stores the measured PMI, and reports the measured PMI through a PDSCH (Physical downlink shared Channel).
The UE stores the measured PMI, wherein the PMI can be stored in a high layer or a bottom layer; the stored contents may be a PMI measured by the UE directly stored, or a precoding vector corresponding to the PMI.
504. And the base station performs MU-MIMO pairing according to the PMIs reported by the UE.
The MU-MIMO pairing algorithm adopts orthogonal pairing of codebooks corresponding to PMIs, namely, whether the codebooks corresponding to PMIs fed back by two users on corresponding subbands are orthogonal or not is judged; if the sub-bands are orthogonal, adding the sub-bands into an MU-MIMO schedulable resource set; then, selecting N sub-bands from the schedulable resource set for MU-MIMO transmission;
in the embodiment of the present invention, if the range of the selected sub-band is not particularly limited, the sub-band may be selected by extracting several adjacent channels for continuous processing, or by randomly extracting several non-adjacent channels for processing.
505. And the base station transmits the PMI information of the paired UE of the current UE to the current UE.
Since the PMI of the current UE is stored in step 503, the base station does not need to issue the PMI corresponding to the UE to the current UE again, and at this time, the base station may issue the PMI corresponding to the paired UE of the current UE through signaling originally used for issuing the PMI corresponding to the current UE.
506. After Precoding (Precoding) is carried out on data corresponding to each UE in a RANK (RANK-1) mode, a base station superposes signals needing to be sent to a plurality of UEs and maps the signals to a specific time-frequency resource to be sent out.
507. And the current UE analyzes the received superposed signals according to the PMI corresponding to the current UE and the PMI corresponding to the paired UE.
At this time, the PMIs of the current UE and the paired UE are combined to obtain the full codebook information used by the base station for signal precoding, and then the full codebook detection is carried out on the received superposed signals according to the obtained full codebook information, so that the signals required to be received by the current UE can be estimated more accurately, and the paired user interference existing between MU-MIMO users is inhibited.
The above numbers of the steps are not used to limit the execution order, for example, the steps 505 and 506 can be executed simultaneously.
In this embodiment of the present invention, step 503 may also be implemented by:
503', the UE reports the measured PMI through the PDSCH channel.
At this time, since the UE does not store its corresponding PMI before reporting the measured PMI, the following step 505 should be:
505' and the base station sends the PMI information of the current UE and the paired UE to the current UE.
In the specific implementation process, the PMI information corresponding to the current UE may be sent to the current UE first, and then the PMI information corresponding to the paired UE may be sent to the current UE;
sending the PMI information corresponding to the paired UE of the current UE to the current UE, and then sending the PMI information corresponding to the current UE;
or, the PMI information of the current UE and its paired UE may be issued to the current UE together.
However, in step 505', since the signaling used by the original base station to issue the PMI corresponding to the current UE is still occupied, the base station needs to carry the PMI corresponding to the paired UE of the current UE through a new signaling; at this time, new signaling overhead must be added to the system, so the solution corresponding to steps 503 and 505 is better than the solution corresponding to steps 503 'and 505', and therefore the former can be preferably adopted in the implementation process of the present invention.
In the embodiment of the present invention, in the process of measuring and transmitting PMI information, CQI information based on a subband may also be measured and transmitted at the same time; because the CQI information contains the modulation mode corresponding to the user terminal, when the base station performs MU-MIMO pairing between a plurality of UEs, the base station can simultaneously pair the plurality of UEs by combining the modulation modes in the PMI information and the CQI information, so that the pairing between the plurality of UEs is more accurate, and the matching degree is higher;
and then, the base station sends the PMI information and the modulation mode corresponding to the paired UE of the current UE to the current UE, so that the interference suppression between the paired users can be more favorably carried out after the UE receives the superposed signal.
According to the method for realizing multi-user MIMO in the CoMP scene, provided by the embodiment of the invention, the optimal matrix index of the paired user terminal of the user terminal is provided for the current user terminal, so that the current user terminal can acquire the full codebook information used in pre-coding before signal transmission, and the current user terminal can perform full codebook detection on the received superposed signals according to the full codebook information, thereby inhibiting the paired user interference existing between MU-MIMO users.
Example four:
as shown in fig. 6, the base station for implementing multi-user MIMO in a CoMP scenario according to the embodiment of the present invention includes a receiving unit 61, a pairing unit 62, a first sending unit 63, a second sending unit 64, and a notification unit 65; in particular, the amount of the solvent to be used,
the notification unit 65 notifies the UE of feedback of the subband-based PMI; after receiving the notification, the UE measures and reports the corresponding PMIs thereof, and then the receiving unit 61 receives PMIs reported by at least two UEs; then, the pairing unit 62 performs MU-MIMO pairing on the at least two UEs according to the PMI; after pairing is completed, the first sending unit 63 issues a PMI of a paired UE of the UE to the current UE; the second sending unit 64 sends the superimposed data of the at least two UEs after being superimposed.
In addition, the first sending unit 63 in this embodiment is further configured to issue a PMI corresponding to the UE to the current UE.
The base station for implementing multi-user MIMO in the CoMP scenario provided in the embodiment of the present invention may further include a third sending unit 66, where the third sending unit 66 is configured to issue a modulation mode of a paired user terminal of the user terminal to the current user terminal; or, the modulation modes respectively corresponding to the user terminal and the paired user terminals thereof are issued to the current user terminal.
The base station for realizing multi-user MIMO in the CoMP scene provided by the embodiment of the invention obtains the full codebook information used in pre-coding before signal transmission by providing the optimal matrix index of the matched user terminal of the user terminal for the current user terminal, so that the current user terminal can analyze the received superposed signal according to the full codebook information, thereby inhibiting the interference of matched users existing between MU-MIMO users.
Example five:
as shown in fig. 7, the user terminal for implementing multi-user MIMO in a CoMP scenario according to the embodiment of the present invention includes a reporting unit 71, a receiving unit 72, an analyzing unit 73, and a measuring unit 74; wherein,
the receiving unit 72 receives a sub-band-based PMI feedback requirement instruction issued by the base station, the measuring unit 74 measures the PMI according to the instruction, and reports the PMI of the current UE to the base station through the reporting unit 71; the base station performs MU-MIMO pairing on the UE according to the PMIs reported by the UE, and then sends the paired information to the UE; at this time, the receiving unit 72 receives a PMI of a paired UE of the current UE issued by the base station, where the paired UE is selected by the base station according to the PMI reported by the current UE, and the receiving unit 72 is further configured to receive a superimposed signal sent by the base station; then, the analyzing unit 73 analyzes the superimposed signal by combining the PMIs of the current UE and its counterpart UE.
The PMI of the current UE used by the UE in signal analysis may be obtained in the following two ways:
first, the user terminal provided in the embodiment of the present invention further includes a storage unit 75, where the storage unit 75 is configured to store the preferred matrix index of the current user terminal measured by the measurement unit 74; the analyzing unit 73 may directly analyze the superposition signal according to the PMI stored in the current UE and the PMI of the paired UE issued by the base station;
secondly, the base station issues the current UE, and the receiving unit 72 at this time is further configured to receive the PMI of the current UE issued by the base station.
In addition, in the embodiment of the present invention, in the process of measuring and transmitting PMI information, a modulation scheme corresponding to the UE may also be measured and transmitted at the same time; therefore, the temperature of the molten metal is controlled,
the saving unit 75 is further configured to save the modulation mode corresponding to the current UE; at this time, the reporting unit 71 is further configured to report the modulation mode of the current user terminal to the base station;
or,
the receiving unit 72 is further configured to receive a modulation mode corresponding to the current UE issued by the base station.
The user terminal for implementing multi-user MIMO in the CoMP scene provided by the embodiment of the invention firstly acquires the preferred matrix index of the paired user terminal of the user terminal, and then acquires the full codebook information used in pre-coding before signal transmission by combining the preferred matrix index of the user terminal, so that the current user terminal can analyze the received superposed signals according to the full codebook information, thereby inhibiting the paired user interference existing between MU-MIMO users.
Example six:
as shown in fig. 8, the system for implementing multi-user MIMO in a CoMP scenario according to the embodiment of the present invention includes a base station 81 and at least two user terminals 82; wherein,
the user terminal 82 is configured to report a preferred matrix index of the current user terminal to the base station 81;
the base station 81 is configured to perform multi-user MIMO pairing on the at least two user terminals 82 according to the received preferred matrix indexes reported by the at least two user terminals 82, then send the preferred matrix indexes of the paired user terminals of the user terminals 82 to the user terminals 82, and send out the data encoded by the at least two user terminals after overlapping;
the ue 82 is further configured to analyze the received superimposed signal by combining the received preference matrix index of the paired ue of the ue and the received preference matrix index of the ue.
In addition, the ue 82 may be further configured to store a preferred matrix index measured by the ue; or,
the base station 81 may be further configured to send the received preference matrix index of a certain user terminal and the preference matrix index of the paired user terminal of the user terminal to the user terminal.
In addition, in the embodiment of the present invention, in the process of measuring and transmitting PMI information, a modulation scheme corresponding to the UE may also be measured and transmitted at the same time; therefore, the temperature of the molten metal is controlled,
the user terminal 82 is further configured to store the modulation mode determined by the user terminal; or,
the base station 81 is further configured to send modulation schemes corresponding to a certain user terminal and a paired user terminal to the user terminal 82.
The system for realizing multi-user MIMO in the CoMP scene, provided by the embodiment of the invention, firstly obtains the preferred matrix index of the user terminal matched with the user terminal, and then obtains the full codebook information used for pre-coding before signal transmission by combining the preferred matrix index of the user terminal, so that the current user terminal can analyze the received superposed signals according to the full codebook information, and the interference of matched users existing between MU-MIMO users is restrained.
The method, the device and the system for realizing multi-user MIMO in the CoMP scene have obvious effect on inhibiting the interference of the paired users between MU-MIMO users; especially aiming at low correlation channels (low correlation among transmitting antennas of a plurality of base stations in practical application), MMSE (minimum mean square error) detection of a full codebook can obtain great interference suppression performance of paired users, and the difference with an ideal non-interference performance curve reaches within 2 dB.
The method, the device and the system for realizing multi-user MIMO under the CoMP scene provided by the embodiment of the invention are not only suitable for the MU-MIMO technology under CoMP, but also suitable for the MU-MIMO technology under non-CoMP, namely, the method, the device and the system for realizing multi-user MIMO provided by the invention can be applied to the MU-MIMO technology based on PMI.
Through the above description of the embodiments, those skilled in the art will clearly understand that the present invention may be implemented by software plus a necessary hardware platform, and may also be implemented by hardware entirely. With this understanding in mind, all or part of the technical solutions of the present invention that contribute to the background can be embodied in the form of a software product, which can be stored in a storage medium, such as a ROM/RAM, a magnetic disk, an optical disk, etc., and includes instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods according to the embodiments or some parts of the embodiments of the present invention.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.