CN106452537B

CN106452537B - Method and apparatus for enhancing feedback in multi-user superposition transmission

Info

Publication number: CN106452537B
Application number: CN201510478236.0A
Authority: CN
Inventors: 王钧; 武卓; 沈钢; 张闽
Original assignee: Nokia Shanghai Bell Co Ltd; Alcatel Lucent SAS
Current assignee: Nokia Shanghai Bell Co Ltd; Alcatel Lucent SAS
Priority date: 2015-08-06
Filing date: 2015-08-06
Publication date: 2019-12-17
Anticipated expiration: 2035-08-06
Also published as: TW201717562A; WO2017021771A3; CN106452537A; WO2017021771A2

Abstract

Embodiments of the present disclosure provide a method and apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding. The method comprises the following steps: receiving first channel state information from a first user equipment; receiving second channel state information from the paired second user equipment; and selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information. The embodiment of the disclosure can enable the base station to select appropriate precoder information from the channel state information reported by the paired user equipment and send the precoder information to the paired user equipment, wherein the near/victim UE can decode an interference signal caused by the far/interfering UE based on the precoder information, and improve the accuracy of decoding the PDSCH data of the near/victim UE by removing the interference signal caused by the far/interfering UE.

Description

Method and apparatus for enhancing feedback in multi-user superposition transmission

Technical Field

Embodiments of the present disclosure relate generally to feedback enhancement, and more particularly, to a method and apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding.

background

In downlink multi-user Superposition Transmission (hereinafter abbreviated MUST), multiple User Equipments (UEs) are paired to enable simultaneous Transmission of their data for more than one layer without separation of time, frequency and spatial layers (i.e., using the same spatial precoding vector or the same transmit diversity scheme on the same resource elements).

for example, FIG. 1 illustrates one such environment. In fig. 1, user equipment 1(UE1) will be severely interfered with by user equipment 2(UE2) because UE2 is at the cell edge and is allocated a large transmit power. The UE1 with an advanced receiver is expected to be able to decode the signal of UE2 first and then remove it from the received signal, and then decode the UE 1's own Physical Downlink Shared Channel (PDSCH) data. Therefore, whether and how much interference caused by the UE2 can be removed is critical for the UE1 to decode its own data. In order to decode the signal of the UE2 at the UE1, information of the allocated transmit power between the two UEs of the pair (i.e., the UE1 and the UE2) is critical to the receiver at the UE 1. Without the power allocation information, it would be quite difficult to correctly decode the interfering signal at the near/victim UE (i.e., UE1), and also impact the accuracy of the UE1 decoding its own PDSCH data after removing the interference caused by the far/interfering UE (i.e., UE 2).

There are currently ten different Transmission Modes (TM) defined for LTE. They differ depending on the specific structure of the antenna mapping, which reference signals are set for demodulation (cell-specific reference signals (CRS) or demodulation reference signals (DM-RS)), and how the Channel State Information (CSI) is acquired by the terminal and fed back to the network. In case of transmission modes 1 to 6, CRS is used for channel estimation, also referred to as CRS based TM. The closed-loop codebook-based coding is associated with transmission mode 4(TM 4). In the case of closed-loop precoding, it is assumed that the network selects the precoder matrix based on feedback from the UE. It is defined in the current 3GPP standard that the UE selects a transmission rank (rank) and precoder matrix based on measurements on CRS, the information of which is then reported to the eNB in the form of Precoder Matrix Indication (PMI) and Rank Indication (RI).

however, in downlink MUSTs, the superimposed signals of paired UEs will be transmitted with respective allocated transmit powers, which may affect the accuracy of acquiring CSI by measuring CRS and the selection of appropriate PMI and RI, since UEs are usually implicitly assumed to be in single-user multiple-input multiple-output (SU-MIMO) rather than MUSTs. More importantly, in addition to being selected for successful decoding of signals of a near UE (e.g., UE1), the selected PMI and RI should also be suitable for decoding of signals of a far UE (e.g., UE2) at the near UE (e.g., UE1), e.g., to remove interference caused by the far UE. In addition, the eNB also needs to indicate the selected PMI and RI to the near and far UEs.

Disclosure of Invention

Embodiments of the present disclosure are directed to a method and apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding.

according to a first aspect of the present disclosure, there is provided a method for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising: receiving first channel state information from a first user equipment; receiving second channel state information from the paired second user equipment; and selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information.

in some embodiments, each of the first channel state information and the second channel state information comprises at least one of: a precoding matrix indication, a rank indication and a channel quality indication.

in some embodiments, each of the first precoder information and the second precoder information comprises at least one of: a precoding matrix indication and a rank indication.

in some embodiments, the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to the center of the cell than the second user equipment.

in some embodiments, the method further comprises: transmitting the first precoder information and the second precoder information to the first user equipment; and transmitting the second precoder information to the second user equipment.

In some embodiments, the method further comprises: transmitting power allocation information to the first user equipment to enable the first user equipment to feed back the first channel state information based on the power allocation information, wherein the power allocation information is used for indicating power allocation between the first user equipment and the second user equipment.

In some embodiments, transmitting power allocation information to the first user equipment comprises: transmitting a plurality of power allocation information to the first user equipment so that the first user equipment feeds back a plurality of first channel state information corresponding to the plurality of power allocation information.

In some embodiments, selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information comprises: selecting the first precoder information for decoding a signal of the first user equipment at the first user equipment; and selecting the second precoder information for decoding signals of the second user equipment at the first user equipment and at the second user equipment.

in some embodiments, selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information further comprises: determining whether the first channel state information and the second channel state information match; and based on determining that the first channel state information and the second channel state information do not match, performing at least one of: causing the first user equipment to be used for single-user transmission; and pairing the first user equipment and a third user equipment for multi-user superposition transmission.

According to a second aspect of the present disclosure, there is provided a method for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising: transmitting first channel state information to a base station; receiving, from the base station, first precoder information for a first user equipment and second precoder information for a paired second user equipment; and decoding a signal received from the base station based on the first precoder information and the second precoder information, wherein the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to a center of the cell than the second user equipment.

In some embodiments, the method further comprises: receiving power allocation information from the base station, the power allocation information indicating power allocation between the first user equipment and the second user equipment.

In some embodiments, the method further comprises: obtaining the first channel state information through measurement of a cell-specific reference signal based on the power allocation information.

In some embodiments, receiving power allocation information from the base station comprises: receiving a plurality of power allocation information from the base station.

in some embodiments, transmitting the first channel state information to the base station comprises: transmitting a plurality of first channel state information corresponding to the plurality of power allocation information to the base station, wherein each first channel state information is respectively obtained through measurement of a cell-specific reference signal based on each power allocation information.

In some embodiments, decoding a signal received from the base station based on the first precoder information and the second precoder information comprises: decoding a signal of the second user equipment based on the second precoder information; removing interference caused by the second user equipment based on the decoded signal of the second user equipment; and decoding the signal after the interference is removed based on the first precoder information.

According to a third aspect of the present disclosure, there is provided a method for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising: transmitting second channel state information to the base station; receiving second precoder information for a second user equipment from the base station; and decoding a signal received from the base station based on the second precoder information.

In some embodiments, the second channel state information comprises at least one of: a precoding matrix indication, a rank indication and a channel quality indication.

In some embodiments, the second precoder information comprises at least one of: a precoding matrix indication and a rank indication.

According to a fourth aspect of the present disclosure, there is provided an apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising: first receiving means configured to receive first channel state information from a first user equipment; second receiving means configured to receive second channel state information from a paired second user equipment; and selecting means configured to select first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information.

In some embodiments, the apparatus further comprises: a first transmitting device configured to transmit the first precoder information and the second precoder information to the first user equipment; and a second transmitting device configured to transmit the second precoder information to the second user equipment.

in some embodiments, the apparatus further comprises: third transmitting means configured to transmit power allocation information to the first user equipment so that the first user equipment feeds back the first channel state information based on the power allocation information, the power allocation information indicating power allocation between the first user equipment and the second user equipment.

In some embodiments, the third transmitting means is configured to transmit a plurality of power allocation information to the first user equipment, so that the first user equipment feeds back a plurality of first channel state information corresponding to the plurality of power allocation information.

In some embodiments, the selection means is configured to: selecting the first precoder information for decoding a signal of the first user equipment at the first user equipment; and selecting the second precoder information for decoding signals of the second user equipment at the first user equipment and at the second user equipment.

In some embodiments, the selection means is further configured to: determining whether the first channel state information and the second channel state information match; and based on determining that the first channel state information and the second channel state information do not match, performing at least one of: causing the first user equipment to be used for single-user transmission; and pairing the first user equipment and a third user equipment for multi-user superposition transmission.

According to a fifth aspect of the present disclosure, there is provided an apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising: fourth transmitting means configured to transmit the first channel state information to the base station; third receiving means configured to receive, from the base station, first precoder information for a first user equipment and second precoder information for a paired second user equipment; and a first decoding device configured to decode a signal received from the base station based on the first precoder information and the second precoder information, wherein the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to a center of the cell than the second user equipment.

in some embodiments, the apparatus further comprises: a fourth receiving device configured to receive power allocation information from the base station, the power allocation information indicating power allocation between the first user equipment and the second user equipment.

in some embodiments, the apparatus further comprises: an obtaining means configured to obtain the first channel state information through measurement of a cell-specific reference signal based on the power allocation information.

In some embodiments, the fourth receiving means is configured to receive a plurality of power allocation information from the base station.

in some embodiments, the fourth transmitting means is configured to transmit a plurality of first channel state information corresponding to the plurality of power allocation information to the base station, wherein each first channel state information is obtained by measurement of a cell-specific reference signal based on each power allocation information, respectively.

in some embodiments, the first decoding means is configured to: decoding a signal of the second user equipment based on the second precoder information; removing interference caused by the second user equipment based on the decoded signal of the second user equipment; and decoding the signal after the interference is removed based on the first precoder information.

According to a sixth aspect of the present disclosure, there is provided an apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising: fifth transmitting means configured to transmit the second channel state information to the base station; fifth receiving means configured to receive second precoder information for a second user equipment from the base station; and a second decoding device configured to decode a signal received from the base station based on the second precoder information.

According to the method and the device for enhancing feedback in multi-user superposition transmission adopting closed-loop precoding, a base station can select appropriate precoder information from channel state information reported by paired user equipment and send the precoder information to the paired user equipment, wherein a near/victim UE can decode an interference signal caused by a far/interference UE based on the precoder information, and the accuracy of decoding PDSCH data of the near/victim UE is improved by removing the interference signal caused by the far/interference UE.

drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure. In the drawings:

FIG. 1 illustrates a schematic diagram of an environment 100 in which embodiments of the present disclosure can be implemented;

Fig. 2 illustrates a flow diagram of a method 200 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure;

Fig. 3 illustrates a flow diagram of a method 300 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure;

Fig. 4 illustrates a flow diagram of a method 400 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure;

fig. 5 illustrates a block diagram of an apparatus 500 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure;

Fig. 6 illustrates a block diagram of an apparatus 600 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure; and

Fig. 7 illustrates a block diagram of an apparatus 700 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure.

Like or corresponding reference characters designate like or corresponding parts throughout the several views.

Detailed Description

Hereinafter, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the drawings and description relate to exemplary embodiments only. It is noted that from the following description, alternative embodiments of the structures and methods disclosed herein are readily contemplated and may be employed without departing from the principles of the present disclosure as claimed.

It should be understood that these exemplary embodiments are given solely for the purpose of enabling those skilled in the art to better understand and to practice the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

the terms "including," comprising, "and the like, as used herein, are to be construed as open-ended terms, i.e.," including/including but not limited to. The term "based on" is "based, at least in part, on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment". Relevant definitions for other terms will be given in the following description.

Hereinafter, a technical scheme for enhancing feedback in multi-user superposition transmission employing closed-loop precoding according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

Fig. 2 illustrates a flow diagram of a method 200 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure. As shown in fig. 2, the method 200 includes steps S201 to S203. The various steps of method 200 will now be described in detail in conjunction with fig. 1 and 2. The method 200 may be performed, for example, by the eNB in fig. 1, according to an embodiment of the disclosure. As shown in fig. 1, UE1 and UE2 are paired UEs for multi-user superposition transmission. UE1 and UE2 are located in the same cell, and UE1 is located in the relative center of the cell, while UE2 is located at the edge of the cell.

at step S201, first channel state information is received from the UE 1. The first Channel State Information (CSI) may include a Channel Quality Indication (CQI), a Precoding Matrix Indication (PMI), and/or a Rank Indication (RI). The first CSI may be obtained by the UE1 by measuring CRS transmitted by the eNB.

According to an embodiment of the present disclosure, prior to step S201, the eNB may transmit power allocation information to the UE1 such that the UE1 makes CRS measurements with the power allocation information to obtain CSI. The fed back CSI is used to suggest to the eNB the most appropriate CQI, RMI and RI for the receiver of the UE 1. The power allocation information may indicate, for example, power allocation between the paired UE1 and UE 2. The eNB may also issue a plurality of power allocation information to the UE1 such that the UE1 feeds back a plurality of first CSI corresponding to the plurality of power allocation information. For example, the plurality of power allocation information issued to the UE1 may indicate that the power allocation ratio between the UE2 and the UE1 during the MUST is 90% and 10%, 80% and 20%, or 70% and 30%, respectively. The UE1 may correspondingly feed back multiple sets of CQI, RMI, and RI to the eNB.

likewise, in step S202, the second CSI is received from the paired UE 2. The second CSI may also include CQI, PMI, and/or RI. The second CSI may be obtained by the UE2 by measuring CRS transmitted by the eNB.

Next, the method 200 proceeds to step S203, and selects first precoder information for the UE1 and second precoder information for the UE2 based on the first CSI and the second CSI. Through steps S201 and S202, the eNB receives multiple sets of CQIs, PMIs, and/or RIs from the UE1 and the UE2, from which the eNB may select first precoder information for decoding signals of the UE1 and second precoder information for decoding signals of the UE 2.

according to embodiments of the present disclosure, the selected first precoder information may be used to decode the UE1 own signal at the UE1, while the selected second precoder information may be used to decode the UE2 signal at the UE1 in addition to the UE2 own signal at the UE 2. This is because, as described above, UE1 and UE2 are user equipment paired for multi-user superposition transmission, UE2 is at the cell edge and may be allocated significantly higher transmit power than UE1 causing severe interference to UE1, so UE1 needs to first decode the signal of UE2 and then improve the accuracy of decoding its own signal by removing the signal of UE2 from the received signal.

According to an embodiment of the present disclosure, when the first CSI and the second CSI fed back to the eNB are the same, the first precoder information and the second precoder information may be determined according to a PMI and an RI contained in the same CSI. When the first CSI and the second CSI fed back to the eNB are different, for example, the PMI and the RI included in the CSI (i.e., the second CSI) fed back by the UE2 may be taken as the second precoder information for decoding the signal of the UE2 at the UE1 and the UE2 in a case where the PMI and the RI can enable the UE1 to decode the signal of the UE2 and have a sufficiently high signal-to-noise ratio. Also, for example, the selected first precoder information and the second precoder information may have the same PMI, and the same or different RI, and so on.

According to an embodiment of the present disclosure, step S203 may further include determining whether the first CSI and the second CSI match, i.e., whether precoder information suitable for decoding the signal of UE2 at UE1 in addition to the signal suitable for decoding UE2 itself at UE2 may be selected. Upon determining that the first CSI and the second CSI do not match, i.e., determining that precoder information that is suitable for decoding UE2 at UE1 in addition to signals suitable for decoding UE2 itself at UE2 cannot be selected, the eNB may select UE1 for single-user transmission; or the eNB may also pair UE1 with another distant UE (e.g., UE3) for multi-user superposition transmission. In this way, the eNB may dynamically switch between single user transmissions (i.e., SU-MIMO), multi-user transmissions, or different pairs between a near UE and different far UEs according to CSI fed back by the UE, i.e., the utilization of each Physical Resource (PRB) may have multiple combinations, e.g., may be used for MUST, SU-MIMO, UE1 and UE2 pairs, UE1 and UE3 pairs, MUST for layer 1, or MUST for layer 1 and layer 2, etc.

According to an embodiment of the present disclosure, the method 200 further includes transmitting the first precoder information and the second precoder information to the UE1 to enable the UE1 to decode the signal of the UE2 using the second precoder information and then to decode its own signal using the first precoder information by removing the signal of the UE2 from the received signal. Further, the method 200 also includes transmitting the second precoder information to the UE2, such that the UE2 decodes its own signal with the second precoder information.

the method 200 ends so far.

Fig. 3 illustrates a flow diagram of a method 300 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure. As shown in fig. 3, the method 300 includes steps S301 to S303. The steps of method 300 will now be described in detail in conjunction with fig. 1 and 3. The method 300 may be performed, for example, by the UE1 in fig. 1, in accordance with an embodiment of the present disclosure.

In step S301, first CSI is transmitted to the eNB. The first CSI may include CQI, PMI, and/or RI. The first CSI may be obtained by the UE1 by measuring CRS transmitted by the eNB.

According to an embodiment of the present disclosure, prior to step S301, the UE1 may receive power allocation information specific to the UE1 from the eNB. The UE1 may utilize the power allocation information for CRS measurements to obtain CSI and feedback to the eNB. The fed back CSI (i.e., the first CSI) is used to suggest to the eNB the most appropriate CQI, RMI, and RI for the receiver of the UE 1. The power allocation information may indicate, for example, power allocation between the paired UE1 and UE 2. A plurality of power allocation information may be received from the eNB, thereby feeding back a plurality of first CSIs corresponding to the plurality of power allocation information. For example, the plurality of power allocation information received from the eNB may indicate that the power allocation ratio between the UE2 and the UE1 during the MUST is 90% and 10%, 80% and 20%, or 70% and 30%, respectively. The UE1 may correspondingly feed back multiple sets of CQI, RMI, and RI to the eNB.

In accordance with embodiments of the present disclosure, to allow an eNB to determine channel state information for downlink multi-user superposition transmissions, paired UEs may report sets of CQIs, PMIs, and/or RIs corresponding to different hypotheses (e.g., regarding different power allocation scenarios and potential codebook restrictions, etc.) to the eNB for selection of precoder matrices for a MUST at the eNB. For example, the UE1 may feed back to the eNB sets of CQIs, PMIs, and/or RIs based on CRS measurements with different power allocation hypotheses. The UE1 may also be configured with an additional set of power allocation indications, which may, for example, require the UE1 to obtain and report CSI for all possible power allocation hypotheses. Note that "all possible power allocation hypotheses" refer to all scenarios with available power allocation indications for the UE1, i.e., under which the UE1 may still obtain acceptable performance with a sufficiently high signal-to-noise ratio (SNR).

further, according to embodiments of the present disclosure, the UE1 may be configured to report CSI to the eNB in a specific time interval or timing triggered manner, for example, by configuring a parameter codebook (indicating a subset of a precoding codebook that is defined for use) for it.

Next, the method 300 proceeds to step S302, receiving first precoder information for the UE1 and second precoder information for the paired UE2 from the eNB. As described above, the eNB, upon receiving multiple sets of CQIs, PMIs, and/or RIs from the paired UE, may select therefrom first precoder information for decoding signals of the UE1 and second precoder information for decoding signals of the UE2, the selected first precoder information may be used for decoding signals of the UE1 itself at the UE1, and the selected second precoder information may be used for decoding signals of the UE2 at the UE1 in addition to decoding signals of the UE2 itself at the UE 2. The eNB may issue the selected first precoder information and second precoder information to the UE 1. Accordingly, at step S302, the UE1 may receive the first precoder information and the second precoder information from the eNB.

next, the method proceeds to step S303, and decodes a signal received from the eNB based on the first precoder information and the second precoder information. As described above, through steps S301 and S302, the UE1 receives first precoder information selected by the eNB for decoding signals of the UE1 and second precoder information for decoding signals of the UE2, the first precoder information may be used for decoding signals of the UE1 itself at the UE1 and the second precoder information may be used for decoding signals of the UE2 at the UE1 in addition to signals of the UE2 itself at the UE 2. Therefore, the UE1 may decode the signal of the UE2 based on the second precoder information; then based on the decoded signal of UE2, removing the interference caused by the second user equipment; and decoding the interfered signal based on the first precoder information.

The method 300 ends at this point.

Fig. 4 illustrates a flow diagram of a method 400 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure. As shown in fig. 4, the method 400 includes steps S401 and S402. The steps of method 400 will now be described in detail in conjunction with fig. 1 and 4. The method 400 may be performed, for example, by the UE2 in fig. 1, in accordance with an embodiment of the present disclosure.

At step S401, the UE2 transmits the second CSI to the eNB. The second CSI may also include CQI, PMI, and/or RI. The second CSI may be obtained by the UE2 by measuring CRS transmitted by the eNB. As described above, the eNB, upon receiving multiple sets of CQIs, PMIs, and/or RIs from the paired UE, may select first precoder information for decoding a signal of the UE1 and second precoder information for decoding a signal of the UE2 therefrom, and issue the second precoder information to the UE 2. Accordingly, at step S402, the UE2 may receive the second precoder information from the eNB, and decode its received PDSCH signals based on the received second precoder information at step S403. The method 400 ends so far.

Fig. 5 illustrates a block diagram of an apparatus 500 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure. As shown in fig. 5, the apparatus 500 comprises a first receiving means 501 configured to receive first channel state information from a first user equipment; a second receiving means 502 configured to receive second channel state information from a paired second user equipment; and a selecting means 503 configured to select the first precoder information for the first user equipment and the second precoder information for the second user equipment based on the first channel state information and the second channel state information.

according to an embodiment of the disclosure, each of the first channel state information and the second channel state information comprises at least one of: a precoding matrix indication, a rank indication and a channel quality indication.

According to an embodiment of the present disclosure, each of the first precoder information and the second precoder information comprises at least one of: a precoding matrix indication and a rank indication.

According to an embodiment of the present disclosure, the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to the center of the cell than the second user equipment.

According to an embodiment of the present disclosure, the apparatus 500 further comprises: a first transmitting device configured to transmit first precoder information and second precoder information to a first user equipment; and a second transmitting device configured to transmit the second precoder information to the second user equipment.

According to an embodiment of the present disclosure, the apparatus 500 further comprises: third transmitting means configured to transmit power allocation information to the first user equipment so that the first user equipment feeds back the first channel state information based on the power allocation information, the power allocation information indicating power allocation between the first user equipment and the second user equipment.

According to an embodiment of the present disclosure, the third transmitting means is configured to transmit the plurality of power allocation information to the first user equipment, so that the first user equipment feeds back a plurality of first channel state information corresponding to the plurality of power allocation information.

according to an embodiment of the present disclosure, the selecting means 503 is configured to: selecting first precoder information for decoding a signal of a first user equipment at the first user equipment; and selecting second precoder information for decoding a signal of the second user equipment at the first user equipment and at the second user equipment.

According to an embodiment of the present disclosure, the selecting means 503 is further configured to: determining whether the first channel state information and the second channel state information match; and based on determining that the first channel state information and the second channel state information do not match, performing at least one of: causing a first user equipment to be used for single user transmission; and pairing the first user equipment and the third user equipment for multi-user superposition transmission.

Fig. 6 illustrates a block diagram of an apparatus 600 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure. As shown in fig. 6, the apparatus 600 includes a fourth transmitting device configured to transmit the first channel state information to the base station; third receiving means configured to receive, from the base station, first precoder information for the first user equipment and second precoder information for the paired second user equipment; and a first decoding device configured to decode a signal received from the base station based on the first precoder information and the second precoder information, wherein the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to a center of the cell than the second user equipment.

According to an embodiment of the present disclosure, the apparatus 600 further comprises: a fourth receiving device configured to receive power allocation information from the base station, the power allocation information indicating power allocation between the first user equipment and the second user equipment.

According to an embodiment of the present disclosure, the apparatus 600 further comprises: an obtaining means configured to obtain the first channel state information through measurement of a cell-specific reference signal based on the power allocation information.

According to an embodiment of the present disclosure, the fourth receiving apparatus is configured to receive a plurality of power allocation information from the base station.

according to an embodiment of the present disclosure, the fourth transmitting means is configured to transmit, to the base station, a plurality of first channel state information corresponding to a plurality of power allocation information, wherein each of the first channel state information is obtained by measurement of a cell-specific reference signal based on each of the power allocation information, respectively.

According to an embodiment of the present disclosure, a first decoding apparatus is configured to: decoding a signal of the second user equipment based on the second precoder information; removing interference caused by the second user equipment based on the decoded signal of the second user equipment; and decoding the interference-removed signal based on the first precoder information.

Fig. 7 illustrates a block diagram of an apparatus 700 for enhancing feedback in multi-user superposition transmission with closed-loop precoding, in accordance with an embodiment of the present disclosure. As shown in fig. 7, the apparatus 700 includes a fifth transmitting device 701 configured to transmit the second channel state information to the base station; a fifth receiving means 702 configured to receive second precoder information for a second user equipment from the base station; and a second decoding device 703 configured to decode the signal received from the base station based on the second precoder information.

in summary, according to the embodiments of the present disclosure, a method and a device for enhancing feedback in multi-user superposition transmission with closed-loop precoding are provided, so that a base station can select appropriate precoder information from channel state information reported by paired user equipments and send the selected precoder information to the paired user equipments, wherein a near/victim UE can decode interference signals caused by a far/interfering UE based on the precoder information, and improve the accuracy of decoding PDSCH data of its own by removing the interference signals caused by the far/interfering UE.

In general, the various example embodiments of this disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Certain aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While aspects of embodiments of the disclosure have been illustrated or described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Also, blocks in the flow diagrams may be viewed as method steps, and/or as operations that result from operation of computer program code, and/or as a plurality of coupled logic circuit elements understood to perform the associated functions. For example, embodiments of the present disclosure include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program containing program code configured to implement the above-described methods.

within the context of this disclosure, a machine-readable medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of a machine-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof.

Computer program code for implementing the methods of the present disclosure may be written in one or more programming languages. These computer program codes may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the computer or other programmable data processing apparatus, cause the functions/acts specified in the flowchart and/or block diagram block or blocks to be performed. The program code may execute entirely on the computer, partly on the computer, as a stand-alone software package, partly on the computer and partly on a remote computer or entirely on the remote computer or server.

Additionally, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking or parallel processing may be beneficial. Likewise, while the above discussion contains certain specific implementation details, this should not be construed as limiting the scope of any invention or claims, but rather as describing particular embodiments that may be directed to particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

various modifications, adaptations, and exemplary embodiments of the foregoing disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. Any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure. Moreover, the foregoing description and drawings present instructive benefits, and other embodiments of the present disclosure set forth herein will occur to those skilled in the art to which these embodiments of the present disclosure pertain.

it is to be understood that the embodiments of the disclosure are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. a method for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising:

Receiving first channel state information from a first user equipment;

Receiving second channel state information from the paired second user equipment;

Selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information; and

transmitting a plurality of power allocation information to the first user equipment to cause the first user equipment to feed back a plurality of first channel state information corresponding to the plurality of power allocation information, the plurality of power allocation information each indicating power allocation between the first user equipment and the second user equipment.

2. the method of claim 1, wherein each of the first channel state information and the second channel state information comprises at least one of: a precoding matrix indication, a rank indication and a channel quality indication.

3. The method of claim 1, wherein each of the first precoder information and the second precoder information comprises at least one of: a precoding matrix indication and a rank indication.

4. The method of claim 1, wherein the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to a center of the cell than the second user equipment.

5. The method of claim 4, further comprising:

Transmitting the first precoder information and the second precoder information to the first user equipment; and

Transmitting the second precoder information to the second user equipment.

6. The method of claim 4, wherein selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first and second channel state information comprises:

selecting the first precoder information for decoding a signal of the first user equipment at the first user equipment; and

Selecting the second precoder information for decoding a signal of the second user equipment at the first user equipment and at the second user equipment.

7. the method of claim 4, wherein selecting first precoder information for the first user equipment and second precoder information for the second user equipment based on the first and second channel state information further comprises:

determining whether the first channel state information and the second channel state information match; and

Based on determining that the first channel state information and the second channel state information do not match, performing at least one of:

Causing the first user equipment to be used for single-user transmission; and

Pairing the first user device and a third user device for multi-user superposition transmission.

8. A method for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising:

Receiving a plurality of power allocation information from a base station, the plurality of power allocation information each indicating a power allocation between a first user equipment and a paired second user equipment;

Transmitting a plurality of first channel state information corresponding to the plurality of power allocation information to the base station;

Receiving, from the base station, first precoder information for the first user equipment and second precoder information for the second user equipment; and

Decoding a signal received from the base station based on the first precoder information and the second precoder information,

wherein the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to the center of the cell than the second user equipment.

9. The method of claim 8, further comprising: each of the plurality of first channel state information is obtained by measurement of a cell-specific reference signal based on each power allocation information, respectively.

10. The method of claim 8, wherein decoding a signal received from the base station based on the first precoder information and the second precoder information comprises:

Decoding a signal of the second user equipment based on the second precoder information;

Removing interference caused by the second user equipment based on the decoded signal of the second user equipment; and

Decoding the interfered signal based on the first precoder information.

11. An apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising:

First receiving means configured to receive first channel state information from a first user equipment;

Second receiving means configured to receive second channel state information from a paired second user equipment;

A selecting device configured to select first precoder information for the first user equipment and second precoder information for the second user equipment based on the first channel state information and the second channel state information; and

a third transmitting device configured to transmit a plurality of pieces of power allocation information to the first user equipment so that the first user equipment feeds back a plurality of pieces of first channel state information corresponding to the plurality of pieces of power allocation information, each of the plurality of pieces of power allocation information indicating power allocation between the first user equipment and the second user equipment.

12. the apparatus of claim 11, wherein each of the first channel state information and the second channel state information comprises at least one of: a precoding matrix indication, a rank indication and a channel quality indication.

13. the apparatus of claim 11, wherein each of the first precoder information and the second precoder information comprises at least one of: a precoding matrix indication and a rank indication.

14. The apparatus of claim 11, wherein the first user equipment and the second user equipment are located in the same cell, and wherein the first user equipment is closer to a center of the cell than the second user equipment.

15. The apparatus of claim 14, further comprising:

A first transmitting device configured to transmit the first precoder information and the second precoder information to the first user equipment; and

A second transmitting device configured to transmit the second precoder information to the second user equipment.

16. The apparatus of claim 14, wherein the selecting means is configured to:

17. the apparatus of claim 14, wherein the selecting means is further configured to:

Causing the first user equipment to be used for single-user transmission; and

18. an apparatus for enhancing feedback in multi-user superposition transmission with closed-loop precoding, comprising:

a fourth receiving device configured to receive a plurality of pieces of power allocation information from the base station, the plurality of pieces of power allocation information each indicating power allocation between the first user equipment and the paired second user equipment;

A fourth transmitting device configured to transmit a plurality of first channel state information corresponding to the plurality of power allocation information to the base station;

Third receiving means configured to receive, from the base station, first precoder information for the first user equipment and second precoder information for the second user equipment; and

A first decoding device configured to decode a signal received from the base station based on the first precoder information and the second precoder information,

19. The apparatus of claim 18, further comprising: an obtaining means configured to obtain each of the plurality of first channel state information through measurement of a cell-specific reference signal based on each power allocation information, respectively.

20. the apparatus of claim 18, wherein the first decoding means is configured to:

Decoding the interfered signal based on the first precoder information.