TW201528711A - Method and apparatus for obtaining DCI of the interfering cell based on common PDCCH/EPDCCH sets - Google Patents

Abstract

The invention provides a method for use in an interfering cell which includes one or more interfering user equipments interfering a victim user equipment of a victim cell, wherein the method comprises the steps of: configuring one or more common PDCCH/EPDCCH sets; informing the victim cell of information about the one or more common PDCCH/EPDCCH sets; and broadcasting network assistance information, the network assistance information including ID of each of interfering user equipment, wherein for each interfering user equipment, an PDCCH/EPDCCH candidate is selected from the EPDCCH set of the interfering user equipment to carry downlink control information of the interfering user equipment and the selected PDCCH/EPDCCH candidate is also contained in the one or more common PDCCH/EPDCCH sets. The invention also provides a method for use in a victim user equipment of a victim cell, the victim user equipment suffering interferences from one or more interfering user equipments of an interfering cell, wherein the method comprises the steps of: receiving information about one or more common PDCCH/EPDCCH sets from the victim cell; receiving network assistance information from the interfering cell, the network assistance information including ID of each interfering user equipment; and decoding the one or more common PDCCH/EPDCCH sets using the ID of each interfering user equipment to obtain downlink control information of each interfering user equipment.

Description

Method and apparatus for obtaining DCI of interfering cells based on a common entity downlink/enhanced physical downlink set

This application is related to a communication system.

The research project on Network-Aided Interference Rejection and Elimination (NAISC) has been agreed to be used in the 12th edition of 3GPP for LTE. NAISC is useful in heterogeneous networks (HetNet), particularly for UEs in the cell range extension (CRE) range where user equipment (UE) as shown in Figure 1 is subject to strong interference from giant cells. In NAISC, the network provides downlink decoding information from at least one UE that interferes with neighboring cells to UEs in the victim cell. For example, in FIG. 1, downlink decoding information of one or more UEs in a giant cell (interfering cell) is transmitted to a UE in a CRE region of a small cell (ie, a victim cell). The UEs in the CRE region can thus decode the transmissions of such UEs in the giant cells and remove their signals (interference) from them via the received signals. This downlink decoding information of interfering cells called network assisted information can be transmitted to more than one UE in the victim cell. It should be understood that NAISC can also be used in a homogeneous network.

Because of the need to schedule information from interfering cells, coordination between the interfering and victim cells is required. Due to the delay in the reload (eg, X2), the interfering cells must be pre-scheduled so that when the network assisted information arrives at the victim cell (and the victim UE), it is still valid. Inter-cell coordination and sharing of scheduling information adds complexity to the eNB. Be aware that it is proposed to broadcast network-assisted information by interfering cells. Because interfering cells know their own schedules, this proposal avoids the need to send network-assisted information to victim cells and avoids the need to interfere with cell pre-scheduling. In addition, the network assistance information will only reach the UE affected by the interference.

A scheme for interfering with cell broadcast network assistance information is proposed in UMTS for NAISC in HetNet. It is further proposed in UMTS that only the UE ID of the UE needs to be interfered in the network assistance information. The victim UE will use the interfering UE ID to decode the HS-SCCH (downlink control channel) and thus obtain decoded information for the interference data channel (ie, HS-PDSCH). These two methods have gained favorable support in UMTS because they avoid coordination between cells. In view of these advantages, the application of these solutions in LTE is therefore also attractive. However, unlike UMTS, the downlink control channel, that is, the EPDCCH and PDCCH are blindly decoded in LTE. Since the PDCCH/EPDCCH candidate set is UE-specific, inter-cell coordination is required to signal PDCCH/EPDCCH candidates that interfere with the UE. Although it is not necessary to pre-generate a complete schedule for interfering cells, the interfering cells need to at least decide to pre-arrange which UEs to share the PDCCH/EPDCCH candidates with the victim cells. Therefore, the technical problem to be solved is to avoid having to share any scheduling resources. And therefore avoid interference and any dynamic coordination between the victim cells.

Based on the above considerations, the main idea of this invention is to introduce one or more common PDCCH/EPDCCH sets known to both interfering cells and victim cells. When the UE is configured to receive network assistance information, the common PDCCH/EPDCCH set is signaled to it (by interfering cell broadcast). If the interfering UE is scheduled and its ID is indicated in the network assistance information, the PDCCH/EPDCCH candidate for the interfering UE is selected from one or more common PDCCH/EPDCCH sets. The one or more common PDCCH/EPDCCH sets should therefore be selected such that they overlap with the configured search space that may indicate any UE in the network assistance information.

In one aspect of the invention, a method is provided for use in an interfering cell comprising one or more interfering user devices, the interfering user device interfering with a victim user device of the victim cell, wherein the method comprises the steps of: - configuring one or more common PDCCH/EPDCCH sets; - notifying the victim cell of information related to the one or more common PDCCH/EPDCCH sets; - broadcasting network assistance information, the network assistance information including interference An ID of the user equipment, wherein for each interfering user equipment, a PDCCH/EPDCCH candidate is selected from the PDCCH/EPDCCH set of the interfering user equipment to carry downlink control information of the interfering user equipment, and the The selected PDCCH/EPDCCH candidate is also included in the one or more common PDCCH/EPDCCH sets.

The method advantageously further comprises the step of: transmitting downlink control information of the interfering user equipment on the selected PDCCH/EPDCCH candidate.

Accordingly, in another aspect of the present invention, there is provided a method for use in a victim user device of a victim cell that is subject to interference from one or more interfering user devices, Wherein the method comprises the steps of: - receiving information related to one or more common PDCCH/EPDCCH sets from the victim cell; - receiving network assistance information from the interfering cell, the network assistance information including each interfering user device ID; - decoding the one or more common PDCCH/EPDCCH sets using the IDs of the interfering user equipments to obtain downlink control information for each interfering user equipment.

With the aforementioned solution of the invention, there is no need to use dynamic signaling between interfering and victim cells. The coordination required here is only a semi-static detail of the common PDCCH/EPDCCH set. Interfering cells only need to notify the victim cells of the common PDCCH/EPDCCH set once, or whenever the interfering cells reconfigure candidates in the common PDCCH/EPDCCH set, it is expected to be infrequent.

Furthermore, for an interfering UE, when the victim UE only needs to decode the common PDCCH/EPDCCH set, the victim UE must be reduced in interference. The UE downlink control information searches for the number of PDCCH/EPDCCH candidates.

It should be understood that the shared PDCCH/EPDCCH set of interfering cells can be shared with more than one victim cell. Similarly, a victim cell can have a common PDCCH/EPDCCH set belonging to different interfering cells. These common PDCCH/EPDCCH sets may or may not overlap.

In an embodiment, the network assistance information further includes a set index for each interfering user equipment, and is used to indicate which of the one or more common PDCCH/EPDCCH sets the interfering user equipment corresponds to, where The decoding step includes: - decoding the common PDCCH/EPDCCH set indicated by the set index using the ID of the interfering user equipment to obtain downlink control information of the interfering user equipment.

For an interfering UE, the victim UE only needs to decode the common PDCCH/EPDCCH set indicated by the set-index, and further reduce the number of candidates that the victim UE must search for the downlink control information of the interfering UE.

It should be understood that an index can be associated with more than one interfering UE, and such an association can be dynamically changed from one frame to another.

In another embodiment, the network assistance information further includes a subset index for each interfering user equipment, to indicate which subset of the common PDCCH/EPDCCH set the interfering user equipment corresponds to, where the decoding The step includes: - decoding the subset of the common PDCCH/EPDCCH set indicated by the subset index using the ID of the interfering user equipment to obtain the Disturbing the downlink control information of the user equipment.

For an interfering UE, the victim UE only needs to decode the secondary set of the common PDCCH/EPDCCH set indicated by the secondary set-index, and further reduces the number of candidates that the victim UE must search for the downlink control information of the interfering UE. In an example, the secondary set contains only one PDCCH/EPDCCH candidate and thus the network assistance information indicates the candidate.

For example, the ID of the interfering UE included in the network assistance information can interfere with the C-RNTI of the UE.

In another embodiment, during the configuration of this common PDCCH/EPDCCH set, the set of potential interfering C-RNTIs can be signaled to the victim UE. The victim UE will attempt to decode the common PDCCH/EPDCCH set using these transmitted C-RNTIs. This will reduce the amount of dynamic transmission required to interfere with the cells. In another embodiment, if the C-RNTI of the interfering UE is different from the C-RNTI in the set of potential interfering C-RNTIs, the interfering cell will only broadcast the C-RNTI that interferes with the UE.

For example, the number of PDCCH/EPDCCH candidates in the common PDCCH/EPDCCH set is equal to the number of additional candidates required for SU-MIMO. The PDCCH/EPDCCH candidate number system 32 for a single stream and the PDCCH/EPDCCH candidate number system 44 for SU-MIMO. The common PDCCH/EPDCCH set will therefore contain 12 candidates per C-RNTI. This maintains its resiliency when scheduling the PDCCH/EPDCCH for the victim UE, while not increasing the robust blind decoding beyond the SU-MIMO capable UE. It should be noted that NAISC can also be used for MU-MIMO, and because the UE is difficult to operate in the same sub-frame in SU-MIMO and MU-MIMO modes, it can be targeted to MU-MIMO. Interfering UEs use candidates for SU-MIMO.

In another embodiment, if the common search space is defined in the EPDCCH in the future, the common PDCCH/EPDCCH set includes one or more candidates in a common search space on the PDCCH or EPDCCH. This allows the eNB to schedule any interfering UEs using one of the candidates in the common search space.

The invention is explained in more detail by way of example with reference to the accompanying drawings in which: FIG. 1 shows the topology of the HetNet network; FIG. 2 shows the interference used in the communication system according to an embodiment of the invention. A flowchart of a method in a cell; Figure 3 shows an example of a common PDCCH/EPDCCH set.

Throughout the figures, like reference numerals will refer to the like, the

The following description illustrates the embodiments. For the sake of clarity, all features not actually practiced are described in this specification. It will of course be understood that in the development of any such actual embodiment, a number of specific decisions should be made to achieve the developer's specific objectives, such as compliance with system-related and business-related limitations, which will vary with the implementation. Furthermore, it will be appreciated that such development attempts may be complex and time consuming, but nevertheless, would have the benefit of this disclosed invention. The routines of people who are familiar with the technology.

The disclosed subject matter will now be described with reference to the accompanying drawings. The various structures, systems, and devices are schematically depicted in the drawings for the purpose of explanation, and are not to be construed as being limited by the details that are known to those skilled in the art. Nevertheless, the illustrative examples are included to describe and explain the subject matter of the present disclosure. Words and phrases used herein are to be interpreted and interpreted as having a meaning consistent with the understanding of the words and phrases of those skilled in the art. There is no attempt to use a particular definition of a metaphorical term or phrase by a consistent term or phrase herein, that is, a definition that is different from the ordinary and customary meanings understood by those skilled in the art. A term or phrase attempt has a certain degree of special meaning, that is, a meaning that is different from what the skilled artisan understands. This particular definition will explicitly and unambiguously provide a specific definition of the term or phrase. The statement is in this specification.

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 2 in conjunction with FIG. 1.

It is assumed that the giant cell line in Fig. 1 interferes with the cell and the victim UE is in the HetNet scenario in the CRE region of the small cell (i.e., the victim cell). Both giant cells and small cells have a system bandwidth of 20 PRB.

First, in step S201, the interfering cells (ie, giant cells) configure two common PDCCH/EPDCCH sets, as shown in FIG. 3, where:

1) A common EPDCCH set 1 comprising PRB3, PRB6, PRB9, PRB12, PRB15, and PRB18.

2) Common EPDCCH set 2, including PRB2, PRB5, PRB10, PRB14, PRB16, and PRB20.

Then, in step S202, the interfering cell notifies the victim cell of the information related to the configured two PDCCH/EPDCCH sets, and also broadcasts the network assistance information in which the ID of the one or more interfering cells is included. The victim cell then sends the message to the victim UE when the victim UE is configured to operate using NAISC.

Consider an interfering UE having an EPDCCH set including PRB2, PRB6, PRB10, PRB12, PRB16, and PRB19. It can be observed that the PRB for this interfering cell overlaps with the partial EPR in the common EPDCCH set 1 and the common EPDCCH set 2. For the sake of brevity, the number of ECCEs in the common EPDCCH set 1 and the common EPDCCH set 2 is the same (they all have the same number of EPDCCH candidates in each aggregation level). It is also assumed that the EPDCCH candidate spans only 1 PRB.

Specifically, in the secondary box n, the interfering UE broadcasts the interfering UE ID (e.g., C-RNTI) in the network assistance information. The interfering cell decides to carry the DCI message using the EPDCCH candidate in PRB 10. Since the common EPDCCH set 2 also contains the same candidate in the PRB 10, the index 2 (pointing to the common EPDCCH set 2) is also transmitted and associated with this interfering UE ID. The victim UE receives an index pointing to the common EPDCCH set 2 and the interfering UE ID, and it can decode the common EPDCCH set 2 indicated by the index using the interfering UE ID to obtain the downlink control information of the interfering UE. The downlink control information includes scheduling information for interfering with the PDSCH, and then the victim UE can use this information to cancel interference from the interfering UE.

It should be noted that the above embodiments are presented for purposes of illustration and not limitation. It is to be understood that changes and modifications may be made without departing from the spirit and scope of the present invention as readily understood by those skilled in the art. Such modifications and variations are considered to be within the scope of the invention and the scope of the appended claims. The scope of the invention is defined by the scope of the appended claims. In addition, any reference numbers in the scope of the claims should not be construed as limiting the scope of the claims. The use of the verb "comprises" and its conjugates does not exclude the presence of the elements or steps in the The indefinite article "a" or "an" or "an"

Claims (15)

A method for use in an interfering cell comprising one or more interfering user devices, the interfering user device interfering with a victim user device of the victim cell, wherein the method comprises the steps of: configuring one or more common a PDCCH/EPDCCH set; notifying the victim cell of information related to the one or more common PDCCH/EPDCCH sets; broadcasting network auxiliary information, where the network auxiliary information includes IDs of each interfering user equipment; wherein the interference is used for each interference And selecting, by the PDCCH/EPDCCH set of the interfering user equipment, a PDCCH/EPDCCH candidate to carry downlink control information of the interfering user equipment, and the selected PDCCH/EPDCCH candidate is also included in the PDCCH/EPDCCH candidate. One or more common PDCCH/EPDCCH sets. The method of claim 1, wherein the method further comprises the step of transmitting downlink control information of the interfering user equipment on the selected PDCCH/EPDCCH candidate. The method of claim 2, wherein the network assistance information further comprises a set index for each interfering user equipment, to indicate that the interfering user equipment corresponds to the one or more common PDCCH/EPDCCH sets. Which collection of. The method of claim 3, wherein the network auxiliary information further includes a subset index for each interfering user device, for indicating the The interference user equipment corresponds to which subset of the common PDCCH/EPDCCH set. The method of claim 1, wherein the ID of each interfering user equipment is C-RNTI. A method for use in a victim user device of a victim cell, the victim user device being subject to interference from one or more interfering user devices, wherein the method comprises the steps of: receiving from the victim cell Information related to one or more common PDCCH/EPDCCH sets; receiving network auxiliary information from the interfering cells, the network auxiliary information including IDs of each interfering user equipment; decoding the one using the IDs of the interfering user equipments respectively Or a plurality of common PDCCH/EPDCCH sets to obtain downlink control information of each interfering user equipment. The method of claim 6, wherein the network assistance information further includes a set index for each interfering user equipment, and is used to indicate that the interfering user equipment corresponds to the one or more common PDCCH/EPDCCH sets. Which set of the decoding, the decoding step includes: decoding the common PDCCH/EPDCCH set indicated by the set index using the ID of the interfering user equipment to obtain downlink control information of the interfering user equipment. The method of claim 7, wherein the network auxiliary information further includes a subset index for each interfering user equipment, and is used to indicate that the interfering user equipment corresponds to the common PDCCH/EPDCCH set. Which subset of the decoding, the decoding step includes: decoding the subset of the common PDCCH/EPDCCH set indicated by the subset index using the ID of the interfering user equipment to obtain downlink control of the interfering user equipment News. A device for use in an interfering cell comprising one or more interfering user devices, the interfering user device interfering with a victim user device of the victim cell, wherein the device comprises: a configuration unit for configuring one or a plurality of common PDCCH/EPDCCH sets; a notification unit, configured to notify the victim cell of information related to the one or more common PDCCH/EPDCCH sets; and a broadcast unit, configured to broadcast network auxiliary information, the network auxiliary information Including an ID of each interfering user equipment; wherein, for each interfering user equipment, selecting a PDCCH/EPDCCH candidate from the EPDCCH set of the interfering user equipment to carry downlink control information of the interfering user equipment, and The selected PDCCH/EPDCCH candidate is also included in the one or more common PDCCH/EPDCCH sets. The device of claim 9, wherein the device further comprises: a transmitting unit, configured to transmit downlink control information of the interfering user equipment on the selected PDCCH/EPDCCH candidate. The device of claim 10, wherein the network auxiliary information further comprises a set index for each interfering user device, for indicating The interfering user equipment corresponds to which of the one or more common PDCCH/EPDCCH sets. The device of claim 11, wherein the network auxiliary information further includes a subset index for each interfering user equipment, and is used to indicate which subset of the common PDCCH/EPDCCH set the interfering user equipment corresponds to. . A device for use in a victim user device of a victim cell, the victim user device being subject to interference from one or more interfering user devices, wherein the device comprises: a first receiving unit for The victim cell receives information related to one or more common PDCCH/EPDCCH sets; the second receiving unit is configured to receive network auxiliary information from the interference cell, where the network auxiliary information includes an ID of each interfering user equipment; And a decoding unit, configured to separately decode the one or more common PDCCH/EPDCCH sets by using IDs of the interfering user equipments to obtain downlink control information of each interfering user equipment. The device of claim 13, wherein the network auxiliary information further includes a set index for each interfering user equipment, and is used to indicate that the interfering user equipment corresponds to the one or more common PDCCH/EPDCCH sets. Which set of the decoding unit is further configured to use the ID of the interfering user equipment to decode the common PDCCH/EPDCCH set indicated by the set index to obtain downlink control information of the interfering user equipment. Such as the device of claim 14 of the patent scope, wherein the network is supplemented The help information further includes a subset index for each interfering user equipment, and is used to indicate which subset of the common PDCCH/EPDCCH set the interfering user equipment corresponds to, wherein the decoding unit is further used to use the interfering user equipment. The ID decodes the subset of the common PDCCH/EPDCCH set indicated by the subset index to obtain downlink control information for the interfering user equipment.