WO2011052978A2

WO2011052978A2 - Method and apparatus for transmitting downlink control signaling

Info

Publication number: WO2011052978A2
Application number: PCT/KR2010/007397
Authority: WO
Inventors: Hong He; Yingyang Li
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2009-10-28
Filing date: 2010-10-27
Publication date: 2011-05-05
Also published as: CN102056299A; WO2011052978A3

Abstract

Embodiments of the present invention provide an method for transmitting a downlink control signaling, including: configuring, CCs for a cell and notifying each UE of configuration information of CCs allocated for the UE; determining a number of DCI-II that is able to be transmitted in a search space of a UE in a PDCCH region of a CC in DCI-II of all target CCs, mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission; and allocating an extended area, and mapping the DCI-II of the residual target CCs into the extended area for transmission.

Description

METHOD AND APPARATUS FOR TRANSMITTING DOWNLINK CONTROL SIGNALING

The present invention relates to mobile communication technologies, and more particularly, to a method and apparatus for transmitting a downlink control signaling.

At present, the Third Generation Partnership Project (3GPP) Organization for Standardization has completed the constitution of the Long Term Evolution (LTE) standardization, and is working on a new standardization based on the LTE standardization and to be submitted to the International Telecommunication Union (ITU) Organization as an alternative scheme of the International Mobile Telecommunications (IMT)-Advance. The standardization is called the LTE-Advanced, and is called the LTE-A for short. The LTE-A system makes the system bandwidth configurable with a method of carrier aggregation. Each carrier unit is called a Component Carrier (CC). A User Equipment (UE) in the LTE-A system may normally work on each CC. The maximal system bandwidth of the LTE-A system is 100M. The frame structure of the LTE-A system is shown in figure 1. Each wireless frame of 10ms includes ten sub-frames of 1ms, and each sub-frame further includes two half-frames of 0.5ms. The system allocates CCs for the UE in each sub-frame. The CC may be used for uplink or downlink transmission, and the maximal bandwidth of each CC is 20M. When an allocated CC is used for downlink transmission, each CC includes a Physical Downlink Control Channel (PDCCH) for transmitting a downlink control signaling and a Physical Downlink Shared Channel (PDSCH) for transmitting downlink data. Boxes drawn with solid lines in figure 1 denote PDCCH regions, while boxes drawn with thin lines denote PDSCH areas.

In the standardization of the LTE system, an eNB may transmit Downlink Control Information (DCI) of different formats for each UE according to transmission modes configured by the UE. That is to say, the eNB encodes the DCI, maps the coded DCI into designated physical resources of the PDCCH. The physical resources refer to resource blocks aggregated with one, two, four or eight Control Channel Elements (CCE)s. Each CCE is constituted by nine Resource Element Groups (REG)s. Each REG is further constituted by four REs. The designated physical resources are normally called a PDCCH search space. After the eNB maps the DCI into the designated physical resources and transmits the DCI to the UE, the UE may obtain the DCI issued by the eNB after performing blind detections with the times limited in the corresponding PDCCH search space according to the current standardization.

In the LTE-A, the initial design principle is that in each CC, the PDCCH of independent transmission downlink is used for dispatching the PDSCH in this CC. However, the problem of mutual interference between cells in a heterogeneous network needs to be taken into consideration. For instance, when a Relay Node and a Pico-Cell are simultaneously configured in a Macro-Cell, how to reduce PDCCH interference from the Macro-Cell eNB on the Relay Node or a Pico-Cell eNB should be taken into consideration, to ensure that each node in the Relay Node cell or Pico-Cell may successfully receive PDCCH information sent from the Relay Node or the Pico-Cell eNB. Thus, the LTE-A discusses the following method for solving the problem: Partial CCs are selected from all available CCs. The selected CCs are used by the Pico-Cell or Relay Node cell for transmitting the downlink PDCCH information thereof. Accordingly, the Macro-Cell transmits the PDCCH information on CCs used by the Pico-Cell or Relay Node cell with a relatively low transmission power or does not transmit any PDCCH information to reduce the PDCCH interference from the Macro-Cell eNB on the Relay Node or the Pico-Cell eNB. While, the Macro-Cell transmits the PDCCH information on the other CCs with the maximal transmission power, to ensure the coverage of the Macro-Cell. Figure 2 illustrates a possible network structure adopting the method. Figure 2 includes a Macro-Cell eNB Macro1, two Pico-Cell eNBs (are Pico1 and Pico2 respectively), and six UEs (are UE1, UE2, UE3, UE4, UE5 and UE6 respectively) which are covered by the Macro1. The UE0 and UE1 are further covered by Pico1, and UE4 and UE5 are further covered by Pico2.

It is supposed that Macro1 allocates two CCs for each UE in its cell (are CC1 and CC2 respectively). In the figure, the transmission of the downlink control signaling in the PDCCH is denoted by dotted line arrows, and the transmission of downlink data in the PDSCH is denoted by solid line arrows.

In order to reduce the PDCCH interference from the Macro-Cell on the Pico-Cell eNB, it is supposed that the Macro-Cell transmits all downlink control signaling on CC1, does not transmit downlink control signaling on the PDCCH of CC2, and transmits the downlink data on the PDSCH of CC1 and CC2. Accordingly, Pico1 and Pico2 transmit the downlink control signaling on the PDCCH of CC2 and transmit the downlink data on the PDSCH of CC2. As illustrated in figure 2, it can be implemented that Macro1, Pico1 and Pico 2 respectively transmit the downlink control information at different time-domain locations, so that the PDCCH interference from the Macro-Cell eNB on the Pico-Cell eNB can be reduced.

It can be seen that the PDCCH interference from the Macro-Cell eNB on the Relay Node or the Pico-Cell eNB can be avoided through making the Macro-Cell eNB, and at least one of the Relay Node and Pico-Cell eNB transmit the PDCCH information on different CCs.

Moreover, as for the CCs used for transmitting the downlink PDCCH information of the Relay Node or Pico-Cell eNB, the PDCCH is occupied by the Relay Node or the Pico-Cell eNB, while the PDSCH resources still can be dispatched by the Macro-Cell. Thus, in order to dispatch the PDSCH resources in the CCs occupied by the Pico-Cell or Relay Node to enhance the throughput of the whole Macro-Cell, the conventional standardization modifies the initial design principle that in each CC, the PDCCH of independent transmission downlink is used for calling the PDSCH in this CC, and advances that one to three bits are added to the conventional DCI for identifying labels of the CCs corresponding to the DCI. That is to say, the PDCCH in this CC transmits DCI used for dispatching the PDSCH resources in other CCs, except for the DCI used for dispatching the PDSCH resources in this CC, so that the LTE-A system can support the application that the PDCCH and the PDSCH indicated by the PDCCH are configured in different CCs. Generally, the DCI used for dispatching the PDSCH resources in this CC is called DCI-I, and the DCI used for dispatching the PDSCH resources in other CCs are called DCI-II. Accordingly, the CC corresponding to the DCI-I is called the source CC, while the CCs corresponding to the DCI-II are called the target CCs. That is to say, the DCI-I is used for indicating the allocation of the PDSCH resources in this CC, while the DCI-II is used for indicating the allocation of the PDSCH resources in other CCs.

At present, the above modification merely represents a discussed direction of the 3GPP, but does not provide any standard scheme for actual operation. However, in the conventional LTE-A system, the capacity of the PDCCH search space in a single CC may not simultaneously satisfy the requirement for transmitting the DCI corresponding to multiple CCs. Thus, aimed at this case, it is necessary to provide a feasible method for allocating resources required for transmitting multiple DCI.

Embodiments of the present invention provide a method and apparatus for transmitting a downlink control signaling, which may guarantee that the eNB may transmit the DCI of multiple target CCs in a single CC.

In order to achieve the above objection, the technical scheme of the present invention is as follows.

A method for transmitting a downlink control signaling, includes:

configuring, by an eNB, CCs for a cell and notifying each UE of configuration information of CCs allocated for the UE;

determining a number of DCI-II that is able to be transmitted in a search space of a UE in a PDCCH region of a CC in DCI-II of all target CCs when there is a source CC in the CCs configured for the UE and the source CC can not send DCI-I of the source CC and the DCI-II of all the target CCs in the search space of the UE in the PDCCH region of the source CC, mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission; and

allocating an extended area, capacity of which is enough to map the DCI-II of all residual target CCs in a PDSCH area allocated by the DCI-I of the UE in the CC, and mapping the DCI-II of the residual target CCs into the extended area for transmission.

The method for configuring, by the eNB, the CCs for the cell and notifying each UE of the configuration information of the CCs allocated for the UE includes:

broadcasting, by the eNB, the CCs configured for the cell through broadcasting channel information, and notifying each UE of the configuration information of the CCs allocated for the UE through a Radio resource control (RRC) signaling; wherein the configuration information at least includes: a type of a downlink CC, and a corresponding relationship between a source CC and a target CC.

The method for determining the number of the DCI-II that is able to be transmitted in the search space of the UE in the PDCCH region of the CC in the DCI-II of all the target CCs includes:

determining the number of the DCI-II that is able to be accommodated by the search space according to the size of the search space of the UE in the PDCCH region of the CC and the size of space occupied by a single DCI-II; wherein the space occupied by a single DCI-II is identical with that occupied by the DCI-I of the same CC, and the size of the space occupied by the DCI-I is resource blocks aggregated with one, two, four, or eight CCEs according to an aggregation level.

determining the number of the DCI-II that is able to be accommodated by the search space according to the size of the search space of the UE in the PDCCH region of the CC and the size of space occupied by a single DCI-II; wherein the number of REs occupied by each DCI-II is identical, and the number of REs occupied by a single DCI-II is n₂=CCE{[(n₁+Δ)mod 4]}×C; n₁ is an aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3; Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3; mod is a remainder operation; CCE{i} denotes the number of CCEs included in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2i，0≤i≤3; C denotes the number of REs included in each CCE; and the number of the REs is a parameter pre-configured by a system.

The method for mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission includes:

generating, by the eNB, the DCI-I according to Channel Quality Indicator (CQI) of the UE, and mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission.

The method for allocating the extended area, the capacity of which is enough to map the DCI-II of all the residual target CCs in a PDSCH area allocated by the DCI-I of the UE in the CC includes:

allocating the extended area, the capacity of which is preset in the PDSCH area allocated by the DCI-I of the UE in the CC; wherein the extended area starts from the first OFDM symbol behind the PDCCH region of the CC in the time-domain; the number of REs included in the extended area is larger than or equal to the number of REs occupied by the DCI-II of all the residual target CCs; the number of the REs occupied by the DCI-II of each residual target CC is identical; and the number of the REs included in the extended area does not include the number of the REs occupied by reference marks in the extended area.

After mapping the DCI-II of the residual target CCs into the extended area for transmission, the method further includes:

mapping downlink data signs to be transmitted in the source CC into an area in the PDSCH area allocated by the DCI-I of the UE in the CC except for the extended area adopting a rate matching method for transmission.

The extended area locates at a PDSCH specific area allocated by the DCI-I transmitted by the UE on the source CC.

The method for mapping the DCI-II of the residual target CCs into the extended area for transmission includes:

performing a concatenation on the DCI-II of the residual target CCs, and mapping all the DCI-II into the extended area for transmission according to an ascending order of a frequency domain first and then a time-domain, starting from the first OFDM sign of the extended area in the time-domain and the sub-carrier with the minimal number of the extended area in the frequency domain.

performing a concatenation on the DCI-II of the residual target CCs, and mapping all the DCI-II into the extended area for transmission according to an ascending order of a time-domain first and then a frequency domain, starting from the first OFDM sign of the extended area, ending at the first time slot of a current sub-frame in the time-domain and selecting sub-carriers, the number of which is in a preset scope from the extended area in the frequency domain.

performing a concatenation on the DCI-II of the residual target CCs, and mapping all the DCI-II into the extended area for transmission according to an ascending order of a time-domain first and then a frequency domain, starting from the first OFDM sign of the extended area, ending at a current sub-frame in the time-domain and selecting sub-carriers, the number of which is in a preset scope from the extended area in the frequency domain.

An apparatus for transmitting a downlink control signaling, includes:

a CC configuration module, configured to configure CCs for a cell, and notify each UE of configuration information of CCs allocated for the UE; and

a mapping transmission module, configured to determine a number of DCI-II that is able to be transmitted in a search space of a UE in a PDCCH region of a CC in DCI-II of all target CCs, when there is a source CC in the CCs configured for the UE, and the source CC is not able to transmit the DCI-I of the CC and the DCI-II of all the target CCs in the search space of the UE in the PDCCH region of the CC, map the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission, allocate an extended area, capacity of which is enough to map the DCI-II of residual target CCs in the PDSCH area allocated by the DCI-I of the UE in the CC, and map the DCI-II of the residual target CCs into the extended area for transmission.

The CC configuration module includes:

a broadcasting unit, configured to broadcast the CCs configured for the cell through broadcasting channel information; and

an allocation unit, configured to notify each UE of the configuration information of the CCs allocated for the UE through a Radio Resource Control (RRC) signaling; wherein the configuration information at least includes: a type of a downlink CC and a corresponding relationship between a source CC and a target CC.

The mapping transmission module includes:

a first mapping transmission unit, configured to determine a number of DCI-II which is able to be accommodated by the search space according to the size of the search space of the UE in the PDCCH region in the CC and the size of the space occupied by a single DCI-II; wherein the space occupied by a single DCI-II is identical with that occupied by the DCI-I in the same CC; the size of the space occupied by the DCI-I is resource blocks aggregated with one, two, four or eight CCEs according to an aggregation level; or further configured to determine the number of DCI-II that is able to be accommodated by the search space according the size of the search space of the UE in the PDCCH region of the CC and the size of the space occupied by a single DCI-II; wherein REs occupied by each DCI-II are identical, and the number of the REs occupied by a single DCI-II is n₂=CCE{[(n₁+Δ)mod 4]}×C; n₁ is the aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3; Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3; mod is a remainder operation; CCE{i} denotes the number of CCEs included in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2ⁱ，0≤i≤3; C denotes the number of REs included in each CCE; the number of the REs is a parameter pre-configured by a system; and further configured to generate the DCI-I according to the CQI of the UE, map the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission; and

a second mapping transmission unit, configured to allocate the extended area, the capacity of which is preset in the PDSCH area allocated by the DCI-I of the UE in the CC; wherein the extended area starts from the first OFDM symbol behind the PDCCH region of the CC in a time-domain; the number of REs included in the extended area is larger than or equal to the number of REs occupied by DCI-II of all the residual target CCs; the number of REs occupied by each DCI-II of the residual target CCs is identical; the number of REs included in the extended area does not include the number of REs occupied by reference signs in the extended area; a formula for computing the number of REs occupied by the DCI-II of the residual target CCs is N2=k×n₂; and further configured to map the DCI-II of the residual target CCs into the extended area for transmission.

The apparatus further includes:

a data mapping transmission module, configured to map downlink data signs to be transmitted in the source CC into an area in the PDSCH area indicated by the DCI-I of the CC except for the extended area adopting a rate matching method for transmission.

It can be seen from the above technical scheme that in the method and apparatus for transmitting a downlink control signaling provided by embodiments of the present invention, when the PDCCH search space of the source CC can not accommodate the DCI-I of the CC and the DCI-II of the target CCs needed to be transmitted by the source CC, the DCI-I is mapped into the PDCCH search space of the source CC through allocating the extended area, the capacity of which is enough to map all the residual target CCs in the PDSCH area of the source CC, and the DCI-II of the target CCs needed to be transmitted by the source CC is also mapped into the extended area. With the technical scheme of the present invention, the eNB can transmit the DCI of multiple target CCs in a single CC.

Figure 1 is a schematic diagram illustrating structure of a radio frame in the conventional LTE-A system;

Figure 2 is a schematic diagram illustration an application when a Macro-Cell eNB coexists with a Pico-Cell eNB in the convention method;

Figure 3 is a flow chart illustrating a method for transmitting a downlink control signaling according to an embodiment of the present invention;

Figure 4 is a schematic diagram illustrating a first kind of CC time-frequency resource mapping location of a system sub-frame according to an embodiment of the present invention;

Figure 5 is a schematic diagram illustrating a second kind of CC time-frequency resource mapping location of a system sub-frame according to an embodiment of the present invention;

Figure 6 is a schematic diagram illustrating a third kind of CC time-frequency resource mapping location of a system sub-frame according to an embodiment of the present invention;

Figure 7 is a schematic diagram illustrating a fourth kind of CC time-frequency resource mapping location of a system sub-frame according to an embodiment of the present invention; and

Figure 8 is a schematic diagram illustrating structure of an apparatus for transmitting a downlink control signaling.

The present invention is further described in detail hereinafter with reference to the accompanying drawings to make the objective, technical solution and merits thereof more apparent.

An embodiment of the present invention first provides a method for transmitting a downlink control signaling. For ease of presentation, relevant definitions and rules are first introduced hereafter.

According to the description of the conventional method, when PDCCH of one or more CCs allocated for a UE by an eNB is occupied by a Relay Node or Pico-Cell eNB, and the one or more CCs further include PDSCH resources needed to be dispatched. The DCI corresponding to the one or more CCs needs to be transmitted through the CC, the PDCCH of which is not occupied by the Relay Node or the Pico-Cell eNB. For ease of differentiation, an embodiment of the present invention classifies the CCs. The CCs include:

CC of the first kind refers to that the DCI in this CC and the PDSCH area allocated by the DCI is transmitted in a same CC. That is to say, the DCI used for controlling the PDSCH downlink scheduling in this CC is transmitted on the PDCCH of CC of this kind.

CC of the second kind refers to that the eNB does not transmit any DCI for the UE in this kind of CC. That is to say, the PDCCH of this kind of CC is occupied by the Relay Node or the Pico-Cell eNB, and the CC includes the PDSCH resources needed to be dispatched for transmitting the downlink data to the UE.

CC of the third kind refers to that the CC not only includes the DCI used for dispatching the PDSCH resources in this CC, but also includes the DCI used for dispatching the PDSCH resources in other kind of CC (i.e. the CC of the second kind).

In actual application, the eNB may allocate the number of the uplink CCs and downlink CCs, and the type of each CC through a Radio Resource Control signaling. How to allocate the number of the uplink CCs and downlink CCs, and the type of each CC is not the key points to be discussed by embodiments of the present invention, and thus is not described in detail.

It can be easily understood by those skilled in the art of the present inveniton that for the CC of the first kind, the DCI can be generated and mapped with a method provided by the Rel.8 of the conventional LTE-A system and the previous standardization thereof. Thus, the present invention does not discuss it in detail. Hereafter, the CCs of the second and third kinds will be described in detail.

For the CC of the second kind, since the CC includes the PDSCH resources needed to be dispatched for transmitting downlink data to the UE, it needs to indicate the transmission of the downlink data with the DCI. Moreover, since the PDCCH of the CC is occupied by the Relay Node or the Pico-Cell eNB, the DCI of the CC merely can be transmitted through the CC of the third kind.

For the CC of the third kind, since the CC of this kind not only includes the DCI (i.e. the DCI-I) for dispatching the PDSCH resources of this CC, but also includes the DCI (i.e. the DCI-II) for dispatching the PDSCH resources in the CC of the second kind, it is easy to find that for a UE, the CCs of the second and third kinds always simultaneously emerge in the process of allocation. That is to say, as long as the CCs allocated for the UE by the eNB include the CC of the second kind, the CCs must simultaneously include the CC of the third kind. The specific number of the CCs of the second and third kinds needs to be determined in the light of actual conditions. It can be easily understood according to the description of the conventional method that the CC of the second kind is the target CC. For ease of description and difference below, the CC of the third kind is accordingly called the source CC. That is to say, the PDCCH search space of the target CC is occupied and the CC includes the PDSCH resources to be dispatched. The source CC simultaneously includes the DCI-I for dispatching the PDSCH resources in this CC and the DCI-II for dispatching the PDSCH resources in the target CC.

Based on the classification of the CCs above, when the CCs allocated for the UE by the eNB include the source CC and the target CCs (It does not limit whether the CC of the first kind exists. Since as described above, for the CC of the first kind, the DCI can be generated and mapped with the method provided by the Rel.8 of the conventional LTE-A system and the previous standardization thereof), there may be several different possibilies that the number of the source CC differs from that of the target CCs according to the capacity of the PDCCH. Since the situation that the PDCCH search space of the source CC may accommodate the DCI-I of this CC and all DCI-II of the target CCs needed to be transmitted by the source CC is not discussed by embodiments of the present invention, this situation is not discussed in detail.

When the PDCCH search space of the source CC can not accommodate the DCI-I of the CC and all DCI-II of the target CCs needed to be transmitted by the source CC, an embodiment of the present invention provides a method as illustrated in figure 3 for transmitting a downlink control signaling. The method includes the following blocks.

Block 301: An eNB allocates CCs for this cell, and notifies each UE of configuration information of CCs allocated for each UE.

The method of block 301 includes: the eNB broadcasts the CCs allocated for this cell through broadcasting channel information, notifies the configuration information of the CCs allocated for each UE through a Radio Resource Control (RRC) signaling. The configuration information at least includes types of the downlink CCs, and a corresponding relationship between a source CC and a target CC.

The corresponding relationship between the source CC and the target CC refers to DCI-II of target CCs transmitted in any source CC. For instance, in actual application, numbers of the target CCs may be used in the RRC signaling for indicating the source CC corresponding to these target CCs.

It should be noted that when the eNB notifies each UE of the configuration information of the CCs allocated for each UE, the configuration information of the CCs allocated for each UE is not always identical. For instance, take a system bandwidth of 60MHz for an example, it is supposed that the eNB allocates four CCs (are CC1, CC2, CC3 and CC4) for this cell, the bandwidths of which are 20MHz, 20MHz, 10MHz and 10MHz. The eNB allocates CC1 and CC2 which are CCs of the first kind, CC3 as the target CC, and CC4 as the source CC for a certain UE. The eNB allocates C1 and C3 which are CCs of the first kind, CC2 as the target CC, and CC4 as the source CC for another UE.

Block 302: When there is a source CC in the CCs allocated for the UEs, and the source CC can not transmit the DCI-I of the CC and the DCI-II of all target CCs in the search space of the UE in the PDCCH region, the number of the DCI-II that can be transmitted in the search space of the UE in the PDCCH region of the CC in the DCI-II of all the target CCs is determined, the DCI-II of the corresponding number and the DCI-I of the source CC is mapped into the search space of the UE in the PDCCH region of the CC for transmission.

The method for determining the number of the DCI-II that can be transmitted in the search space of the UE in the PDCCH region of the CC in the DCI-II of all the target CCs includes:

determining the number of the DCI-II that can be accommodated by the search space according to the size of the search space of the UE in the PDCCH region of the CC and the size of the space occupied by a single DCI-II. The space occupied by a single DCI-II is identical with that occupied by the DCI-I in the same CC. The size of the occupied space is the resource blocks aggregated with one, two, four or eight CCEs according to an aggregation level.

Alternatively, the number of the DCI-II that can be accommodated by the search space is determined according to the size of the search space of the UE in the PDCCH region of the CC and the size of the space occupied by a single DCI-II. The number of REs occupied by each DCI-II is identical, and the number of the REs occupied by a single DCI-II is n₂=CCE{[(n₁+Δ)mod 4]}×C. n₁ is the aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3. Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3. mod is a remainder operation. CCE{i} denotes the number of CCEs included in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2ⁱ，0≤i≤3. C denotes the number of REs included in each CCE. The number of the REs is a parameter pre-configured by the system.

The method for mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC includes:

generating, by the eNB, the DCI-I according to a Channel Quality Indicator (CQI), mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission.

Block 303: An extended area, cappacity of which is enough to map the DCI-II of all the residual target CCs is allocated in the PDSCH area allocated by the DCI-I of the UE in the CC, and the DCI-II of all the residual target CCs is mapped into the extended area for transmission.

The method for allocating the extended area, the capacity of which is enough to map the DCI-II of all the residual target CCs in the PDSCH area allocated by the DCI-I of the UE in the CC includes:

allocating an extended area, the capacity of a preset size in the PDSCH area allocated by the DCI-I of the UE in the CC. In time-domain, the extended area starts from the first OFDM symbol behind the PDCCH region of the CC. The number of the REs included in the extended area is larger than or equal to the number of REs occupied by the DCI-II of all the residual target CCs. The number of REs occupied by the DCI-II of each residual target CC is identical. The number of the REs included in the extended area does not include the number of REs occupied by reference marks in the extended area.

In actual application, generally, it is supposed that the number of REs occupied by each DCI-II is identical with that occupied by the DCI-I of the source CC. However, it should be noted that since the embodiment of the present invention simultaneously transmits the control signaling (i.e. the DCI-II) and the downlink data utilizing the PDSCH under the above circumstance, in order to enhance the transmission performance of the DCI-II, preferably, the eNB dynamically sets the number of the REs included in the extended area according to the detection of the uplink reference marks, and the detection of ACK/NACK information of the PDSCH in the CC dispatched by the DCI-II. Accordingly, the number of the REs included in this extended area is larger than or equal to that occupied by the DCI-II of all the residual target CCs. Accordingly, the formula for computing the number of the REs occupied by the DCI-II of all the residual target CCs is:

N2=k×n₂，and n₂=CCE{[(n₁+Δ)mod 4]}×C. N2 is the number of REs occupied by the DCI-II of the residual target CCs. n₂ is the number of REs occupied by a single DCI-II. k is the number of DCI-II of the residual target CCs. n₁ is an aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3. Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3. mod is a remainder operation. CCE{i} denotes the number of CCEs included in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2ⁱ，0≤i≤3. C denotes the number of REs included in each CCE. The number of the REs is a parameter pre-configured by the system.

At the same time, it should be noted that when the DCI-II and DCI-I adopt the same aggregation level (i.e., the number of REs occupied by the DCI-II is identical with that of the DCI-I), the times of the blind detections performed in the extended area may be reduced when the UE receives the source CC. The reason is as follows.

After receiving the source CC, the UE first needs to perform the blind detection on the DCI-I included in the PDCCH search space. When the DCI-II and DCI-I adopt the same aggregation level, once determining the aggregation level of the DCI-I through performing the blind detection on the PDCCH search space, the UE obtains the aggregation level of the DCI-II in the extended area, and thus determines the number of REs needs to be read each time the blind detection is performed. For instance, when the UE determines that the aggregation level of the DCI-I is zero in the process of the blind detection performed on the PDCCH search space, since the DCI-I and DCI-II have the same aggregation level, the number of REs occupied by the DCI-I is identical with that of the DCI-II, and is 36. When performing the blind detection on the extended area to parse the DCI-II, the UE only needs to perform the blind detection according to a mode of reading 36 REs each time until parsing needed DCI-II. If the DCI-I and DCI-II adopt different aggregation levels or it can learn in advance whether the DCI-I and DCI-II adopt the same aggregation level, even though the UE has completed the blind detection on the PDCCH search space and obtained the DCI-I, the UE still needs to try with 36, 72, 144 or 288 REs until parsing the DCI-II when performing the blind detection on the extended area. Apparently, if the DCI-I and DCI-II adopt the same aggregation level, the times of the blind detections performed by the UE may be greatly reduced, and the detection efficiency of the UE may be enhanced, the time delay of the network and power consumption of the UE may be reduced.

It can be seen that when the DCI-II adopts a higher aggregation level, the method may enhance the transmission performance of the DCI-II. When the DCI-II and DCI-I adopt the same aggregation level, the method may reduce the power consumption of the UE and the time delay of the network and enhance the detection efficiency of the UE. Thus, an adjustment may be made in specific embodiments according to different performance requirements and schemes of the operator, and the present invention does not make any limitation.

Moreover, the situation that the PDCCH search space of the source CC can not accommodate the DCI-I of this CC and the DCI-II of all the target CCs needs to be transmitted in the PDCCH search space may be further classified into the following two situations.

First: There is downlink data needed to be transmitted in the source CC, and the PDCCH search space of the source CC can not totally accommodate the DCI-I of the CC and the DCI-II of all the target CCs needs to be transmitted in the PDCCH search space.

Second: There is no downlink data needs to be transmitted in the source CC, and the PDCCH search space of the source CC can not totally accommodate the DCI-II of all the target CCs needs to be transmitted in the PDCCH search space.

For either of the above situations, there may be a plurality of methods for mapping the DCI-II of the residual target CCs into the extended area. Embodiments of the present invention do not make specific limitation on the methods. Several examples are listed below for description.

a: A concatenation is performed on the DCI-II of the residual target CCs. Starting from the first OFDM sign of the extended area in the time-domain and the sub-carrier with the minimal number of the extended area in the frequency domain, the concatenation DCI-II is mapped into the extended area according to an ascending order of the frequency domain first and then the time-domain.

b: A concatenation is performed on the DCI-II of the residual target CCs. Starting from the first OFDM sign of the extended area and ending at the first time slot of the current sub-frame in the time-domain, and selecting the sub-carriers, the number of which is in a preset scope from the extended area in the frequency domain, the concatenation DCI-II is mapped into the extended area according to an ascending order of the time-domain first and then the frequency domain.

c: A concatenation is performed on the DCI-II of the residual target CCs. Starting from the first OFDM sign of the extended area and ending at the current sub-frame in the time-domain, and selecting the sub-carrier, the number of which is in a preset scope from the extended area in the frequency domain, the concatenationd DCI-II is mapped into the extended area according to an ascending order of the time-domain first and then the frequency domain.

It can be seen that in the method a, the concatenationd DCI-II is mapped into all the bandwidth of the extended area in an ascending order of the number of the sub-carrier, starting from the minimal sub-carrier of the first OFDM sign in the extended area allocated by the DCI-I, and then the concatenationd DCI-II is mapped into all the bandwidth of the extended area in an ascending order of the number of the sub-carrier, starting from the minimal sub-carrier of the second OFDM sign in the extended area; the rest may be deduced by analogy, until the concatenationd DCI-II is completely mapped into the extended area.

In the method b, the mapping scope in the time-domain starts from the first OFDM sign of the extended area and ends at the first time slot of the current sub-frame, while the mapping scope in the frequency domain is any section of all the bandwidth in the extended area, as long as the capacity of the extended area is enough to accommodate the concatenationd DCI-II. The specific mapping is performed in the time-domain first, and then in the frequency domain.

Similarly, in the method c, the mapping scope in the time-domain starts from the first OFDM sign of the extended area and ends at the current sub-frame, while the mapping scope in the frequency domain is any section of all the bandwidth in the extended area, as long as the capacity of the extended area is enough to accommodate the concatenationd DCI-II. The specific mapping is also performed in the time-domain first, and then in the frequency domain.

It should be noted that the above examples are merely preferable embodiments obtained by making minor modification to the conventional standardization and equipment, and should not be considered as the limitation to the embodiments of the present invention. A person skilled in the art of the present invention may make other changes and modifications to the examples, as long as the capacity of the extended area is enough to accommodate the concatenationd DCI-II.

Finally, it should be understood by a person skilled in the art of the present invention that since the extended area is located at the PDSCH area, and the mapping locations of the reference marks are determined by parameters, such as the configuration of antennas in the PDSCH area, the time-domain resource locations occupied by reference signals should be dropped when the DCI-II is mapped into the extended area allocated by the DCI-I.

After block 303, the method may further include:

Block 304: The downlink data signs waiting for transmission in the source CC are mapped into the area in the PDSCH area indicated by the DCI-I of the CC except for the extended area adopting a rate matching method for transmission.

In order to further explain the above method for transmitting the downlink control signaling, several specific embodiments are given below for specific description. The above embodiments mainly describe how to perform the resource mapping of the DCI-I and DCI-II, and determine the PDCCH search space and extended area for transmitting the DCI. In order to avoid verbosity of the description, the detailed description on the well-known functions or apparatus is omitted below.

First, in this embodiment, it is supposed that the system bandwidth is 60M, four CCs (CC1, CC2, CC3, and CC4) are configured in this cell. The bandwidths of the CCs are 20MHz, 20MHz, 10MHz and 10MHz. The eNB broadcasts in the whole cell with broadcasting information and notifies each UE of the configured number of the CCs and types with the RRC signaling. In this embodiment, it is supposed that the eNB configures CC1 as the CC of the third kind, CC2 as the CC of the second kind for the current UE, and configures the number of the downlink transmission antennas as two. Then, the CC time-frequency resource location of a sub-frame in the system is illustrated in figure 4. It is supposed that in this embodiment, each CC of the current sub-frame of the UE has PDSCH data for transmission, and the PDCCH region in CC1 occupies three OFDM signs, while the PDCCH region of CC2 occupies two OFDM signs. As illustrated in figure 4, the first three OFDM signs (i.e. the first three lines of CC1) of the CC1 indicate the PDCCH region of CC1, and the PDSCH area of CC1 starts from the fourth OFDM symbol of the current sub-frame. While the first two OFDM signs (i.e. the first two lines of CC2) of CC2 indicate the PDCCH region of CC2, and the PDSCH area of CC2 starts from the third OFDM symbol of the current sub-frame.

The eNB accordingly generates two different DCI according to the allocated CCs and types thereof. The DCI includes the DCI-I which is used for indicating the PDSCH resources in CC1. It is supposed that the eNB allocates a third PRB used for transmitting PDSCH information. The DCI further includes the DCI-II which is used for indicating the resource allocation of the PDSCH in CC2. It is supposed that the eNB allocates a twelfth PRB which is used for transmitting PDSCH information of CC2 in C2 for the UE.

For CC1, the eNB determines to transmit the DCI-I on CC1 with CCE aggregation level zero according to the CQI fed back by the UE and the detected uplink reference marks. That is to say, the eNB sends the DCI-I with 36 REs. According to the method mentioned above, the DCI-II and DCI-I may use the same CCE aggregation level. That is to say, the DCI-II is also transmitted on CC1 with 36 REs. The eNB tries to map the DCI-I and DCI-II into the search space of the UE in the PDCCH region of CC1 for transmission according to its own scheduling algorithm. In this embodiment, the PDCCH region of the UE in CC1 only can accommodate one DCI. Thus, the eNB first maps the DCI-I into the REs in the PDCCH region of CC1, and determines the number and location of the REs included in the extended area.

In this embodiment, the method for mapping the DCI-II into the extended area includes: starting from the first OFDM sign of the PDSCH area allocated by the DCI-I of the same CC, i.e. starting from the fourth OFDM sign of the third PRB in time-domain, and occupying the whole bandwidth of the PDSCH area allocated by the DCI-I in the same CC, i.e. all sub-carriers of the third PRB, increasing the number of the OFDM signs in the extended area in the time-domain first, and then in the frequency domain according to the total number of the REs (is 36 REs in this embodiment) needed for transmitting the DCI-II in the extended area, until all the DCI-II signs to be transmitted are mapped. The REs do not include the REs for transmitting the reference marks. The residual REs are used for bearing the PDSCH information to be transmitted in this CC.

The mapping locations of the DCI-I and DCI-II are illustrated in figure 4. The area shown in right slash shaded part is the time-frequency resource location for mapping the DCI-I in the PDCCH of CC1. The area constituted by vertical and horizontal crossed line shaded part and dot shaded part is the extended area allocated by the DCI-I in the PDSCH of CC1. The dot shaded part area is the time-frequency resource location for mapping the DCI-II. While the vertical and horizontal crossed line shaded part is the mapping location of downlink data signs to be transmitted in CC1. The PDSCH resources pointed out by the DCI-II locate at CC2. The location of the PDSCH resources is the area shown in left slash shaded part. In light of the above configuration of the system and the number of the downlink transmission antennas being two, the mapping location of the reference marks is the area shown in the dark shaded part and left and right crossed line shaded part.

It can be easily seen from the figure that the mapping method of the DCI-II in this embodiment includes: mapping the DCI-II into the location of each OFDM sign first in left-to-right order and then in top-to-bottom order. The left and right edges of the mapping location of the DCI-II are defined by the bandwidth of the PDSCH area allocated by the DCI-I.

Second, in this embodiment, the configuration of the system and assumption conditions are identical with those of the previous embodiment. The only difference is the mapping method of the DCI-II. The method for mapping the DCI-II into the extended area includes: starting from the first OFDM sign of the PDSCH area allocated by the DCI-I of the same CC, i.e. starting from the fourth OFDM sign of the third PRB in time-domain, and ending at the first time slot of the current sub-frame, increasing the number of the sub-carriers to be transmitted in the extended area first in the time-domain, and then in the frequency domain according to the total number of the REs (is 36 REs in this embodiment) needed for transmitting the DCI-II in the extended area, until all the DCI-II signs to be transmitted are mapped. The REs do not include the REs used for transmitting the reference marks. The residual REs are used for bearing the PDSCH information to be transmitted in this CC.

Then, the CC time-frequency resource location in a sub-frame of the system is shown in figure 5. The area shown in right slash shaded part is the time- frequency resource location for mapping the DCI-I in the PDCCH of CC1. The area constituted by vertical and horizontal crossed line shaded part and dot shaded part is the extended area allocated by the DCI-I in the PDSCH of CC1. The area shown in the dot shaded part is the time-frequency resource location for mapping the DCI-II. While the area shown in the vertical and horizontal crossed line shaded part is the mapping location of downlink data signs to be transmitted in CC1. The PDSCH resources pointed out by the DCI-II locate at CC2. The location of the PDSCH resource is the area shown in left slash shaded part. In light of the above configuration of the system and the number of the downlink transmission antennas being two, the mapping location of the reference marks is the area shown in the dark shaded part and left and right crossed line shaded part.

It can be easily seen from the figure that the mapping method of the DCI-II in this embodiment includes: mapping the DCI-II into the location of each OFDM sign first in left-to-right order and then in top-to-bottom order. The top and bottom edges of the mapping location of the DCI-II are defined by the starting location of the PDSCH of the CC and ending location of the first time slot of the current sub-frame.

Third, in this embodiment, the configuration of the system and assumption conditions are still identical with those of the previous embodiment. The only difference is the mapping method of the DCI-II. The method for mapping the DCI-II into the extended area includes: starting from the first OFDM sign of the PDSCH area allocated by the DCI-I of the same CC, i.e. starting from the fourth OFDM sign of the third PRB in time-domain, and ending at the current sub-frame, increasing the number of the sub-carriers to be transmitted in the extended area first in the time-domain, and then in the frequency domain according to the total number of the REs (is 36 REs in this embodiment) needed for transmitting the DCI-II in the extended area, until all the DCI-II signs to be transmitted are mapped. The REs do not include the REs used for transmitting the reference marks. The residual REs are used for bearing the PDSCH information to be transmitted in this CC.

Then, the CC time-frequency resource location in a sub-frame of the system is shown in figure 6. The area shown in right slash shaded part is the time- frequency resource location for mapping the DCI-I in the PDCCH of CC1. The area constituted by vertical and horizontal crossed line shaded part and dot shaded part is the extended area allocated by the DCI-I in the PDSCH of CC1. The area shown in the dot shaded part is the time-frequency resource location for mapping the DCI-II. While the area shown in the vertical and horizontal crossed line shaded part is the mapping location of downlink data signs to be transmitted in CC1. The PDSCH resources pointed out by the DCI-II locate at CC2. The location of the PDSCH resources is the area shown in left slash shaded part. In light of the above configuration of the system and the number of the downlink transmission antennas being two, the mapping location of the reference marks is the area shown in the dark shaded part and left and right crossed line shaded part.

It can be easily seen from the figure that the mapping method of the DCI-II in this embodiment includes: mapping the DCI-II into the location of each OFDM sign first in left-to-right order and then in top-to-bottom order. The top and bottom edges of the mapping location of the DCI-II are defined by the starting location of the PDSCH of the CC and ending location of the current sub-frame.

Fourth, in this embodiment, it is supposed that the system bandwidth is 50M, four CCs (are CC1, CC2, CC3, and CC4) are configured in this cell. The bandwidths of the CCs are 20MHz, 10MHz, 10MHz and 10MHz. The eNB broadcasts in the whole cell with broadcasting information and notifies each UE of the configured number of the CCs and types with the RRC signaling. The CC time-frequency resource location of a sub-frame of the system is shown in figure 4. In this embodiment, it is supposed that the eNB configures CC1 as the CC of the third kind, CC2 and CC3 as the CCs of the second kind for the current UE, and configures the number of the downlink transmission antennas as two. It is supposed that in this embodiment, both of the current sub-frames CC2 and CC3 of the UE has PDSCH data for transmission, while CC1 does not have PDSCH data for transmission. The PDCCH region in CC1 occupies three OFDM signs, while the PDCCH region of CC2 and CC3 occupies two OFDM signs. As illustrated in figure 7, the first three OFDM signs (i.e. the first three lines of CC1) of the CC1 indicate the PDCCH region of CC1, and the PDSCH area of CC1 starts from the fourth OFDM symbol of the current sub-frame. While the first two OFDM signs (i.e. the first two lines of CC2 and CC3) of CC2 and CC3 indicate the PDCCH region of CC2 and CC3, and the PDSCH area of CC2 and CC3 starts from the third OFDM symbol of the current sub-frame. The eNB accordingly generates two different kinds of DCI. The DCI includes the DCI-I which is used for indicating the PDSCH resources in CC1. The PDSCH is only used for transmitting the DCI-II. It is supposed that the eNB allocates a third PRB used for transmitting PDSCH information for the UE. The DCI further includes a first DCI-II which is used for indicating the resource allocation of the PDSCH in CC2 and a second DCI-II which is used for indicating the resource allocation of the PDSCH in CC3. It is supposed that the eNB allocates a twelfth PRB which is used for transmitting the PDSCH information of CC2 in C2 for the UE, and allocates a tenth PRB which is used for transmitting the PDSCH information of CC3 in C3 for the UE.

In this embodiment, the scope of the extended area starts from the first OFDM sign of the PDSCH area allocated by the DCI-I of the same CC, i.e. starts from the fourth OFDM sign of the third PRB, and ends at the current sub-frame in the time-domain. The number of the sub-carriers in the extended area is increased first in the time-domain, and then in the frequency domain according to the total number of the REs (is 72 REs in this embodiment) needed for transmitting the DCI-II in the extended area, until all the DCI-II signs to be transmitted are mapped. In this embodiment, the extended area is not only used for bearing the first DCI-II for dispatching the PDSCH of CC2, but also used for bearing the second DCI-II for dispatching the PDSCH of CC3. The REs do not include the REs for transmitting the reference marks.

The mapping locations of the DCI-I and DCI-II are illustrated in figure 7. The area shown in right slash shaded part is the time-frequency resource location for mapping the DCI-I in the PDCCH of CC1. The area constituted by dot shaded part and vertical and horizontal crossed line shaded part is the extended area allocated by the DCI-I in the PDSCH of CC1. The dot shaded part is the time-frequency resource location for mapping the first DCI-II. While the horizontal line shaded part is the time-frequency resource location for mapping the second DCI-II. The vertical and horizontal crossed line shaded part is the mapping location of downlink data signs to be transmitted in CC1. The PDSCH resources pointed out by the first DCI-II locate at CC2, the location of which is the area shown in left slash shaded part. The PDSCH resources pointed out by the second DCI-II locate at CC3, the location of which is the area shown in the vertical line shaded part. In light of the above configuration of the system and the number of the downlink transmission antennas being two, the mapping location of the reference marks is the area shown in the dark shaded part and left and right crossed line shaded part.

It can be easily seen from the figure that the mapping method of the concatenationd DCI-II in this embodiment includes: mapping the DCI-II into the location of each OFDM sign first in top-to-bottom and then in left-to-rigth order order. The top and bottom edges of the mapping location of the DCI-II are defined by the starting location of the PDSCH of the CC and the ending location of the current sub-frame.

Based on the above method, an embodiment of the present invention further provides an apparatus for transmitting a downlink control signaling. The structure of the system is shown in figure 8. The apparatus includes a CC configuration module 810 and a mapping transmission module 820.

The CC configuration module 810 is configured to configure CCs for a cell and notify each UE of configuration information of CCs allocated for the UE.

The mapping transmission module 820 is configured to determine number of DCI-II that can be transmitted in a search space of a UE in the PDCCH region of the CC in the DCI-II of all target CCs when there is a source CC in the CCs configured for the UE and the DCI-I of the CC and DCI-II of all target CCs can not be transmitted in the search space of the UE in the PDCCH region of the source CC, map the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission. The mapping transmission module 820 is further configured to allocate an extended area, the capacity of which is enough to map the DCI-II of residual target CCs in the PDSCH area allocated by the DCI-I of the UE in the CC, and map the DCI-II of the residual target CCs into the extended area for transmission.

The CC configuration module 810 includes a broadcasting unit 811 and an allocation unit 812.

The broadcasting unit 811 is configured to broadcast the CCs configured for the cell through broadcasting channel information.

The allocation unit 812 is configured to notify each UE of the configuration information of the CCs allocated for it through a RRC signaling. The configuration information at least includes a type of a downlink CC, and a corresponding relationship between the source CC and the target CC.

The mapping transmission module 820 includes a first mapping transmission unit 821 and a second mapping transmission unit 822.

The first mapping transmission unit 821 is configured to determine the number of DCI-II that can be accommodated by the search space according the size of the search space of the UE in the PDCCH region of the CC and the size of the space occupied by a single DCI-II. The space occupied by a single DCI-II is identical with that occupied by the DCI-I in the same CC. The size of the space occupied by the DCI-I is resource blocks aggregated with one, two, four or eight CCEs according to an aggregation level.

Alternatively, the first mapping transmission unit 821 is configured to determine the number of DCI-II that can be accommodated by the search space according the size of the search space of the UE in the PDCCH region of the CC and the size of the space occupied by a single DCI-II. REs occupied by each DCI-II is identical, and the number of the REs occupied by a single DCI-II is n₂=CCE{[(n₁+Δ)mod 4]}×C. n₁ is the aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3. Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3. mod is a remainder operation. CCE{i} denotes the number of CCEs included in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2ⁱ，0≤i≤3. C denotes the number of REs included in each CCE. The number of the REs is a parameter pre-configured by the system.

The first mapping transmission unit 821 is further configured to generate the DCI-I according to CQI of the UE, map the DCI-II of the corresponding number and the DCI-I of the CC into the search space of the UE in the PDCCH region of the CC for transmission.

The second mapping transmission unit 822 is configured to allocate an extended area, the capacity of which is preset in the PDSCH area allocated by the DCI-I of the UE in the CC. The extended area starts from the first OFDM symbol behind the PDCCH region of the CC in time-domain. The number of REs included in the extended area is larger than or equal to the number of REs occupied by DCI-II of all the residual target CCs. The number of REs occupied by each DCI-II of the residual target CC is identical. The number of REs included in the extended area does not include the number of REs occupied by the reference marks in the extended area. The formula for computing the number of REs occupied by the DCI-II of the residual target CCs is N2=k×n₂. The meaning of n₂ is identical with that described above, and is not described any more.

The second mapping transmission unit 822 is further configured to map the DCI-II of the residual CCs into the extended area for transmission.

Preferably, the apparatus further includes a data transmission module 830, configured to map downlink data signs to be transmitted in the source CC into an area in the PDSCH area indicated by the DCI-I of the CC except for the extended area according to a rate matching method for transmission.

In view of the above, it can be seen that in the method and apparatus for transmitting a downlink control signaling provided by embodiments of the present invention, when the PDCCH search space of the source CC can not totally accommodate the DCI-I of the CC and the DCI-II of the target CCs needed to be transmitted by the PDCCH search space, the extended area, the capacity of which is able to map the DCI-II of all residual target CCs in the PDSCH are of the source CC, the DCI-I is mapped into the PDCCH search space of the source CC, and the DCI-II of the target CCs which needs to be transmitted by the source CC is mapped into the extended area, so that the eNB can transmit the DCI of multiple target CCs in a single CC. Moreover, preferably, when the DCI-II adopts a higher aggregation level, the scheme can enhance the transmission performance of the DCI-II. When the DCI-I and DCI-II adopt the same aggregation level, the scheme may reduce the power consumption of the UE and the time delay of the network, and enhance the detection efficiency of the UE.

Claims

A method for transmitting a downlink control signaling, comprising:

configuring CCs for a cell by an eNBand notifying each UE of configuration information of CCs allocated for the UE;

determining the number of DCI-II of all target CCs that is able to be transmitted in the search space of a UE which exisiting in the PDCCH region of a source CC when there is a source CC in the CCs configured for the UE and the source CC can not send DCI-I of the source CC and the DCI-II of all the target CCs in the search space of the UE which existing in the PDCCH regionregion of the source CC, mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE which existing in the PDCCH region of the source CC for transmission; and

allocating an extended area, capacity of which is enough to map the DCI-II of all residual target CCs in a PDSCH area allocated by the DCI-I of the UE in the source CC, and mapping the DCI-II of the residual target CCs into the extended area for transmission.
The method according to claim 1, wherein configuring the CCs for the cell by the eNB and notifying each UE of the configuration information of the CCs allocated for the UE comprises:

broadcasting the CCs configured for the cell by the eNB through broadcasting channel information, and notifying each UE of the configuration information of the CCs allocated for the UE through a Radio resource control (RRC) signaling; wherein the configuration information at least comprises: a type of a downlink CC, and a corresponding relationship between a source CC and a target CC.
The method according to claim 2, wherein determining the number of the DCI-II that is able to be transmitted in the search space of the UE in the PDCCH region of the CC in the DCI-II of all the target CCs comprises:

determining the number of the DCI-II that is able to be accommodated by the search space according to the size of the search space of the UE in the PDCCH region of the CC and the size of space occupied by a single DCI-II; wherein the space occupied by a single DCI-II is identical with that occupied by the DCI-I of the same CC, and the size of the space occupied by the DCI-I is resource blocks aggregated with one, two, four, or eight CCEs according to an aggregation level.
The method according to claim 2, wherein determining the number of the DCI-II that is able to be transmitted in the search space of the UE in the PDCCH region of the CC in the DCI-II of all the target CCs comprises:

determining the number of the DCI-II that is able to be accommodated by the search space according to the size of the search space of the UE in the PDCCH region of the CC and the size of space occupied by a single DCI-II; wherein the number of REs occupied by each DCI-II is identical, and the number of REs occupied by a single DCI-II is n₂=CCE{[(n₁+Δ)mod 4]}×C; n₁ is an aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3; Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3; mod is a remainder operation; CCE{i} denotes the number of CCEs comprised in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2ⁱ，0≤i≤3; C denotes the number of REs comprised in each CCE; and the number of the REs is a parameter pre-configured by a system.
The method according to claim 3 or 4, wherein mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission comprises:

generatingthe DCI-I by the eNB according to Channel Quality Indicator (CQI) feedback by the UE, and mapping the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE which existing in the PDCCH region of the source CC for transmission.
The method according to claim 5, wherein allocating the extended area, the capacity of which is enough to map the DCI-II of all the residual target CCs in a PDSCH area allocated by the DCI-I of the UE in the CC comprises:

allocating the extended area, the capacity of which is preset in the PDSCH area allocated by the DCI-I of the UE in the source CC; wherein the extended area starts from the first OFDM symbol behind the PDCCH region of the source CC in the time-domain; the number of REs comprised in the extended area is larger than or equal to the number of REs occupied by the DCI-II of all the residual target CCs; the number of the REs occupied by the DCI-II of each residual target CC is identical; and the number of the REs comprised in the extended area does not comprise the number of the REs occupied by reference signals in the extended area.
The method according to claim 6, after mapping the DCI-II of the residual target CCs into the extended area for transmission, further comprising:

mapping downlink data symbols to be transmitted in the source CC into an area in the PDSCH region allocated by the DCI-I of the UE in the CC except for the extended area adopting a rate matching method for transmission.
The method according to claim 7, wherein the extended area locates at a PDSCH specific area allocated by the DCI-I transmitted by the UE on the source CC.
The method according to any of claims 6 to 8, wherein mapping the DCI-II of the residual target CCs into the extended area for transmission comprises:

performing a concatenation on the DCI-II of the residual target CCs, and mapping all the DCI-II into the extended area for transmission according to an ascending order of a frequency domain first and then a time-domain, starting from the first OFDM symbol of the extended area in the time-domain and the sub-carrier with the minimal number of the extended area in the frequency domain.
The method according to any of claims 6 to 8, wherein mapping the DCI-II of the residual target CCs into the extended area for transmission comprises:

performing a concatenation on the DCI-II of the residual target CCs, and mapping all the DCI-II into the extended area for transmission according to an ascending order of a time-domain first and then a frequency domain, starting from the first OFDM symbol of the extended area, ending at the first time slot of a current sub-frame in the time-domain and selecting sub-carriers, the number of which is in a preset scope from the extended area in the frequency domain.
The method according to any of claims 6 to 8, wherein mapping the DCI-II of the residual target CCs into the extended area for transmission comprises:

performing a concatenation on the DCI-II of the residual target CCs, and mapping all the DCI-II into the extended area for transmission according to an ascending order of a time-domain first and then a frequency domain, starting from the first OFDM symbol of the extended area, ending at a current sub-frame in the time-domain and selecting sub-carriers, the number of which is in a preset scope from the extended area in the frequency domain.
An apparatus for transmitting a downlink control signaling, comprising:

a CC configuration module, configured to configure CCs for a cell, and notify each UE of configuration information of CCs allocated for the UE; and

a mapping transmission module, configured to determine a number of DCI-II that is able to be transmitted in a search space of a UE in a PDCCH region of a CC in DCI-II of all target CCs, when there is a source CC in the CCs configured for the UE, and the source CC is not able to transmit the DCI-I of the CC and the DCI-II of all the target CCs in the search space of the UE in the PDCCH region of the CC, map the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission, allocate an extended area, capacity of which is enough to map the DCI-II of residual target CCs in the PDSCH area allocated by the DCI-I of the UE in the CC, and map the DCI-II of the residual target CCs into the extended area for transmission.
The apparatus according to claim 12, wherein the CC configuration module comprises:

a broadcasting unit, configured to broadcast the CCs configured for the cell through broadcasting channel information; and

an allocation unit, configured to notify each UE of the configuration information of the CCs allocated for the UE through a Radio Resource Control (RRC) signaling; wherein the configuration information at least comprises: a type of a downlink CC and a corresponding relationship between a source CC and a target CC.
The apparatus according to claim 12, wherein the mapping transmission module comprises:

a first mapping transmission unit, configured to determine a number of DCI-II which is able to be accommodated by the search space according to the size of the search space of the UE in the PDCCH region in the CC and the size of the space occupied by a single DCI-II; wherein the space occupied by a single DCI-II is identical with that occupied by the DCI-I in the same CC; the size of the space occupied by the DCI-I is resource blocks aggregated with one, two, four or eight CCEs according to an aggregation level; or further configured to determine the number of DCI-II that is able to be accommodated by the search space according the size of the search space of the UE in the PDCCH region of the CC and the size of the space occupied by a single DCI-II; wherein REs occupied by each DCI-II are identical, and the number of the REs occupied by a single DCI-II is n₂=CCE{[(n₁+Δ)mod 4]}×C; n₁ is the aggregation level of the DCI-I of the UE in the CC, and 0≤n₁≤3; Δ is an offset configured for the UE by the eNB through the RRC signaling, and 0≤Δ≤3; mod is a remainder operation; CCE{i} denotes the number of CCEs comprised in the DCI-II when the aggregation level of the DCI-II is i, and CCE{i}=2ⁱ，0≤i≤3; C denotes the number of REs comprised in each CCE; the number of the REs is a parameter pre-configured by a system; and further configured to generate the DCI-I according to the CQI of the UE, map the DCI-II of the corresponding number and the DCI-I of the source CC into the search space of the UE in the PDCCH region of the CC for transmission; and

a second mapping transmission unit, configured to allocate the extended area, the capacity of which is preset in the PDSCH area allocated by the DCI-I of the UE in the CC; wherein the extended area starts from the first OFDM symbol behind the PDCCH region of the CC in a time-domain; the number of REs comprised in the extended area is larger than or equal to the number of REs occupied by DCI-II of all the residual target CCs; the number of REs occupied by each DCI-II of the residual target CCs is identical; the number of REs comprised in the extended area does not comprise the number of REs occupied by reference signs in the extended area; a formula for computing the number of REs occupied by the DCI-II of the residual target CCs is N2=k×n₂; and further configured to map the DCI-II of the residual target CCs into the extended area for transmission.
The apparatus according to any of claims 12 to 14, further comprising:

a data mapping transmission module, configured to map downlink data signs to be transmitted in the source CC into an area in the PDSCH area indicated by the DCI-I of the source CC except for the extended area adopting a rate matching method for transmission.