CN101841892B - Method, equipment and system for indicating and detecting PDCCH in a carrier aggregation system - Google Patents

Abstract

The invention discloses a method for detecting PDCCH in a carrier aggregation system. The method comprises the following steps that: a terminal detects the PDCCH which belongs to the terminal from one carrier in the carrier aggregation system, then determines position information of the detected PDCCH, and finally detects the PDCCH which belongs to the terminal from the carrier which corresponds to the position information. Due to the adoption of the method, the terminal does not need to blindly detect each carrier, so the number of blind detection is reduced. The invention also discloses a method and equipment for indicating the physical downlink control channel (PDCCH) in the carrier aggregation system, and the equipment and the system for detecting the PDCCH.

Description

PDCCH indication and detection method, device and system in carrier aggregation system

technical field

The present invention relates to the communication field, in particular to a method, device and system for indicating and detecting a physical downlink control channel in a carrier system.

Background technique

With the development of communication systems, the requirements for the quantity and rate of data transmission are getting higher and higher. Therefore, based on the long term evolution standard (Long term evaluation, LTE), the LTE-A system, an evolved version of LTE, is proposed. The LTE-A system will support a larger bandwidth than the LTE system (the carrier bandwidth of the LTE system is 20MHz, and the bandwidth of the LTE-A system can reach 100MHz). In order to meet the bandwidth requirements of the LTE-A system, multiple LTE Carriers are aggregated together to form a carrier aggregation system to meet the bandwidth requirements of LTE-A.

The data carried by the Physical Downlink Control Channel (PDCCH) is channel resource allocation information and other control information. In the LTE system, a PDCCH can be transmitted on 1, 2, 4 or 8 consecutive Control Channel Elements (CCEs), where CCEs are composed of several Resource Elements (REs). RE is the smallest time-frequency unit of the LTE system, including one subcarrier in the frequency domain and one OFDM symbol in the time domain. The number of multiple consecutive CCEs is called an aggregation level, for example, 4 consecutive CCEs are called the aggregation level of CCE is 4.

In order for the terminal to receive resource allocation information and other control information correctly and quickly, the base station needs to indicate to the terminal the location of the PDCCH and the number of CCEs occupied by the PDCCH. However, in order to save channel overhead, the LTE system does not indicate the above information to the terminal, but the terminal uses a blind detection method to search for the PDCCH belonging to the terminal. The method for the terminal to perform blind detection is as follows: the terminal first takes its own identity, the number of the subframe used, the aggregation level of the CCEs to be occupied, and the number of CCEs contained in the control area of the subframe as input, and obtains the CCE through a specific hash algorithm. The terminal is at the starting position of the search space corresponding to each aggregation level in this subframe. The search space contains a series of PDCCH candidate sets. The search spaces corresponding to different aggregation levels contain different numbers of candidate PDCCHs. The terminal will be in each search space Each candidate PDCCH is detected until the PDCCH belonging to the terminal is obtained.

Since the carrier aggregation system is formed by aggregating multiple LTE carriers, the PDCCH in the carrier aggregation system can be designed as the structure shown in FIG. 1 . In the schematic structural diagram of FIG. 1 , the terminal has an independent PDCCH on each carrier, and the PDCCH in a carrier is used to indicate information such as resource allocation of the terminal in the carrier. The PDCCH used to indicate resource allocation in a certain carrier is transmitted on the carrier.

The PDCCH structure shown in Figure 1 has little changes to the standard structure of LTE and has good backward compatibility. However, when the terminal performs blind detection in the carrier aggregation system, the number of blind detections will increase with the carrier aggregation system. It grows linearly with the increase of the number of carriers. If in the LTE specification, a terminal needs at most about 40 times of blind detection in a subframe to obtain the PDCCH belonging to the terminal, in a carrier aggregation system composed of N carriers, it needs at most N×40 times of blind detection to obtain For all the PDCCHs belonging to the terminal, due to the large number of blind detections, the detection cost and power consumption of the terminal are increased.

Contents of the invention

Embodiments of the present invention provide a PDCCH indication, detection method, device and system in an aggregated carrier system, so that when a terminal detects its own PDCCH, the number of times of blind detection is reduced.

A method for indicating a physical downlink control channel PDCCH in a carrier aggregation system, the method comprising the following steps:

The base station determines the PDCCH belonging to a certain terminal, and determines the position information of the carrier having the PDCCH, wherein each PDCCH corresponds to a carrier, and the carriers corresponding to any two PDCCHs are different;

The base station separately determines the offset of each PDCCH in the carrier search space;

The base station places the determined location information in the PDCCH belonging to the terminal, places the determined offset of the PDCCH in the carrier in the PDCCH that places the location information corresponding to the carrier, and the location information placed in the PDCCH corresponds to The carrier of the PDCCH is different from the carrier of the PDCCH, which is used to instruct the terminal to determine the carrier with the PDCCH according to the location information and according to the offset placed in the PDCCH, from the determined carrier with the PDCCH The PDCCH belonging to the terminal is detected in the search space in .

A method for detecting PDCCH, said method comprising the following steps:

The terminal detects the PDCCH belonging to the terminal from a carrier in the carrier aggregation system;

The terminal determines the location information placed in the detected PDCCH;

The terminal determines an offset placed in the detected PDCCH;

The terminal determines a carrier having a PDCCH belonging to the terminal according to the position information placed in the detected PDCCH;

The terminal detects the PDCCH belonging to the terminal from the determined search space in the carrier according to the offset placed in the detected PDCCH.

A device for indicating a PDCCH in a carrier aggregation system, the device comprising:

A position information determining module, configured to determine a PDCCH belonging to a certain terminal, and determine the position information of a carrier having the PDCCH, wherein each PDCCH corresponds to a carrier, and any two PDCCHs correspond to different carriers;

an offset determination module, configured to determine the offset of each PDCCH in the carrier search space;

a placement module, configured to perform the following operations: place the determined location information in the PDCCH belonging to the terminal, place the determined offset of the PDCCH in the carrier into the PDCCH in which the location information corresponding to the carrier is placed, And the carrier corresponding to the position information placed in the PDCCH is different from the carrier where the PDCCH is located, wherein the operation is used to instruct the terminal to determine the carrier with the PDCCH according to the position information and according to the carrier placed in the PDCCH The offset is used to detect the PDCCH belonging to the terminal from the determined search space of the carrier having the PDCCH.

A device for detecting PDCCH, including a first detection module, a position information detection module, an offset detection module, and a second detection module, the second detection module includes a first execution submodule and a second execution submodule, wherein:

A first detection module, configured to detect a PDCCH belonging to a certain terminal from a carrier in the carrier aggregation system;

A location information detection module, configured to determine the location information placed in the most recently detected PDCCH;

The second detection module is configured to detect the PDCCH belonging to the terminal from the carrier corresponding to the location information, specifically including:

The first execution submodule is used to determine the carrier with the PDCCH belonging to the terminal according to the location information determined by the location information detection module;

The second execution submodule is configured to detect the PDCCH belonging to the terminal from the search space in the carrier determined by the first execution submodule according to the offset detected by the offset detection module.

A communication system, the system includes a base station and a terminal, wherein the base station includes a location information determination module, an offset determination module, and a placement module, and the terminal includes a first detection module, a location information detection module, an offset A detection module and a second detection module, the second detection module includes a first execution submodule and a second execution submodule:

The position information determination module is configured to determine the PDCCH belonging to the terminal, and determine the position information of the carrier having the PDCCH, wherein each PDCCH corresponds to a carrier, and any two PDCCHs correspond to different carriers;

The offset determination module is configured to respectively determine the offset of each PDCCH in the carrier search space;

The placement module is configured to place the determined location information in the PDCCH belonging to the terminal, and place the determined offset of the PDCCH in the carrier into the PDCCH in which the location information corresponding to the carrier is placed, wherein , the carrier corresponding to the location information placed in the PDCCH is different from the carrier where the PDCCH is located;

The first detection module is configured to detect a PDCCH belonging to the terminal from a carrier in the carrier aggregation system;

The location information detection module is configured to determine the location information placed in the detected PDCCH;

The offset detection module is configured to determine the offset placed in the most recently detected PDCCH when it is determined that there is an undetected PDCCH belonging to the terminal in the carrier aggregation system;

The second detection module is configured to detect the PDCCH belonging to the terminal from the carrier corresponding to the location information, wherein:

The first execution submodule is configured to determine a carrier having a PDCCH belonging to the terminal according to the position information placed in the detected PDCCH;

The second execution submodule is configured to detect the PDCCH belonging to the terminal from the determined search space in the carrier according to the offset placed in the detected PDCCH.

In the present invention, the position information of other PDCCHs belonging to the same terminal is placed in the PDCCH, so that after the terminal detects the PDCCH belonging to the terminal in a carrier, it can directly determine other PDCCHs belonging to the terminal according to the position information placed in the PDCCH. The carrier of the PDCCH, therefore, the terminal does not need to perform blind detection on each carrier, reducing the number of times of blind detection.

Description of drawings

FIG. 1 is a schematic structural diagram of a PDCCH in a carrier aggregation system in the prior art;

FIG. 2 is a flow chart of steps in a method for indicating a PDCCH in a carrier aggregation system in Embodiment 1 of the present invention;

FIG. 3 is a schematic diagram of a modified PDCCH structure in Embodiment 1 of the present invention;

FIG. 4 is a schematic diagram of a modified PDCCH structure in Embodiment 1 of the present invention;

FIG. 5 is a schematic diagram of a PDCCH structure after an offset is placed in the PDCCH in Embodiment 1 of the present invention;

FIG. 6 is a schematic diagram of a modified PDCCH structure in Embodiment 1 of the present invention;

FIG. 7 is a schematic diagram of a PDCCH structure after an offset is placed in the PDCCH in Embodiment 1 of the present invention;

FIG. 8 is a flow chart of the steps of a method for detecting a PDCCH in Embodiment 2 of the present invention;

FIG. 9 is a schematic structural diagram of a PDCCH indication device in a carrier aggregation system according to Embodiment 3 of the present invention;

FIG. 10 is a schematic structural diagram of a device for detecting a PDCCH in Embodiment 4 of the present invention;

FIG. 11 is a schematic structural diagram of a communication system in Embodiment 5 of the present invention.

Detailed ways

In an aggregated carrier system, each carrier may have a PDCCH belonging to a certain terminal, or may not have a PDCCH belonging to the terminal. If the terminal wants to detect all the PDCCHs belonging to itself in the aggregated carrier system, each carrier must Perform a blind test. In order to reduce as much as possible the number of times of blind detection by the terminal in the carrier aggregation system, the present invention modifies the structure of the PDCCH on the base station side, and puts other PDCCHs belonging to the same terminal in some specific fields The location information of the carrier, so that after the terminal detects the PDCCH belonging to the terminal in a carrier, it can further determine other carriers that may have the PDCCH of the terminal according to the location information placed in the PDCCH. Therefore, the terminal can directly check the location information The corresponding carrier is detected to query its own PDCCH without blind detection of all carriers in the aggregated carrier system. Compared with the prior art, the solution of the embodiment of the present invention can detect the When all PDCCHs are used, reduce the times of carrier blind detection.

In the solutions of the various embodiments of the present invention, the location information set for searching the carrier is the carrier identifier of the carrier.

The present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in FIG. 2, it is an indication method for the PDCCH in the carrier aggregation system in Embodiment 1 of the present invention. The indication method mainly includes the following steps:

Step 101: the base station determines the PDCCH belonging to a certain terminal.

In Embodiment 1 of the present invention, when the base station needs to communicate with the terminal, the base station carries some control information in the communication process in the PDCCH.

Step 102: The base station determines the correspondence between a carrier in the carrier aggregation system and a PDCCH of the carrier, wherein each PDCCH corresponds to a carrier, and any two PDCCHs correspond to different carriers.

Step 103: the base station determines the carrier identity of the carrier with the PDCCH.

Step 104: The base station places the determined carrier identifier in the PDCCH, and the carrier corresponding to the location information placed in the PDCCH is different from the carrier where the PDCCH is located.

In Embodiment 1 of the present invention, the placement of the carrier identifier by the base station includes but is not limited to the following two methods:

The first way: place each carrier identifier in a PDCCH respectively, that is, place a carrier identifier with other PDCCH carriers in a PDCCH.

The second way: a carrier with a PDCCH is used as the main carrier, and among the determined carrier identities, other carrier identities except the carrier identification corresponding to the main carrier are placed in the PDCCH of the main carrier.

The base station may notify the terminal of the current way to place the carrier identifier through the indication information.

In this embodiment, the carrier identifier placed in the PDCCH is used to instruct the terminal to determine the carrier that may have the PDCCH belonging to the terminal according to the carrier identifier, and the terminal can use the carrier identifier placed in the detected carrier to detect the carrier that may belong to the terminal. The carrier where the PDCCH of the terminal is located.

If the base station uses the above-mentioned first method to place the carrier identifier, after the terminal detects a PDCCH, it determines the corresponding carrier according to a carrier identifier contained in it, and then detects the PDCCH belonging to the terminal from the determined carrier, and so on , until all PDCCHs belonging to the terminal are detected.

If the base station uses the above-mentioned second method to place the carrier ID, the terminal obtains other multiple carrier IDs with PDCCH carriers from the PDCCH of the main carrier, and then determines the carrier corresponding to each carrier ID, and then determines all the carriers belonging to the terminal. PDCCH.

If the number of determined PDCCHs is at least 3, when using the above-mentioned first method to place carrier identities, in the case where the carrier identities corresponding to any two carriers are placed in the PDCCHs owned by each other, for example, the first carrier In the case where the PDCCH in the second carrier is placed with the second carrier identifier, and the PDCCH in the second carrier is placed with the first carrier identifier, after the terminal detects the PDCCH in the first carrier, it can detect the second carrier identifier according to the second carrier identifier. However, the PDCCH in the second carrier is placed with the first carrier ID that has been detected, so the carrier ID can no longer be used for detection. When it is determined that there are still undetected PDCCHs, it should be detected through blind detection. The PDCCH of the terminal, and then perform subsequent operations according to the carrier identifier in the PDCCH.

After the structure of the PDCCH is improved using the solution of Embodiment 1, the terminal can easily determine the carrier where the undetected PDCCH is located. In order to further reduce the number of times the terminal detects the PDCCH on the determined carrier, after step 103 room, may also include:

Step 103A: the base station respectively determines the offset of each PDCCH in the carrier search space.

After step 104, the following steps are also included:

Step 105: Put the determined offset of the PDCCH in the carrier into the PDCCH storing the carrier identity corresponding to the carrier.

The field for placing the carrier identifier in the PDCCH is not limited. For example, the carrier identifier can be placed in the transmission power control (Transmission Power Control, TPC) field in the PDCCH or the resource allocation field in the PDCCH, or a new field in the PDCCH To place the carrier identifier, the carrier identifier can also be placed in the DCI Format field in the PDCCH.

For example, when using the TPC field to place the carrier identifier, since the TPC field can contain 2 bits of information, the carrier identifiers that can be indicated by the TPC field are 0 to 4, that is to say, when using the TPC field to place the carrier identifier, 5 carriers can be supported Composed of aggregated carrier systems. When the maximum bandwidth supported by the LTE-A system is 100MHz and the maximum bandwidth supported by the LTE system is 20MHz, the maximum bandwidth of the LTE-A system can be satisfied by aggregating five 20MHz LTE carriers. Therefore, the TPC field can be used to place the carrier identifier requirements.

For another example, by increasing the granularity of resource allocation, the number of bits required for the resource allocation field in the PDCCH on each carrier is reduced, and the vacant bits can be used to place carrier identifiers.

If the carrier identifier is placed in the DCI Format field, bits (bitmap) can be placed in the DCI Format field to indicate which carriers have PDCCHs. If there are 5 carriers in the carrier aggregation system, the bitmap contains 5 bits. In the above-mentioned first method of placing the carrier ID, if it is desired to indicate that the second carrier has a PDCCH, the bitmap is <01000>; in the above-mentioned second method of placing the carrier ID, if it is desired to indicate that the second carrier and If there is a PDCCH on the fifth carrier, the bitmap is <01001>.

The embodiment of the present invention does not limit the field for placing the offset in the PDCCH. If the DCI format of the PDCCH belonging to the terminal is 1, 1A, 1B, 1C, 1D, 2 or 2A, the hybrid automatic Place the offset in the retransmission request process identifier (HARQ process id) field or the newly added field in the PDCCH; if the DCI format of the PDCCH belonging to the terminal is 0, you can place the offset in the cyclic shift of the demodulation reference signal in the PDCCH The offset is placed in the bit (cyclic shift for demodulation reference signal, Cyclic shift for DM RS) field or a new field in the PDCCH.

For example, when using the HARQ process id field to place the offset, the HARQ process id field contains 3-bit information, and the value that can be indicated is 0-8. According to the LTE specification, when the CCE aggregation level is 1 or 2, its search space contains 6 candidate PDCCHs. When the CCE aggregation level is 4 or 8, its search space contains 2 candidate PDCCHs. Therefore, using the HARQ process id field can Satisfy the placement offset requirements.

For another example, by increasing the granularity of resource allocation, the number of bits required for the resource allocation field in the PDCCH on each carrier is reduced, and the vacant bits can be used to place offsets. If the number of vacated bits is large, the requirements for placing the carrier identifier and the offset can be met at the same time, or the bits vacated by increasing the granularity can be used to place the carrier identifier and the offset at the same time.

In the method of Embodiment 1, if the base station adopts the above-mentioned first method of placing the carrier identifier, the base station needs to predetermine the last PDCCH belonging to the terminal. The purpose of this is to make the terminal stop when it detects the last PDCCH. Loop detection operation.

Specifically, when the carrier identifier is the number of the carrier in the aggregated carrier system, the base station can arrange the carriers with the PDCCH in ascending order of the carrier number, and use the PDCCH in the carrier with the largest carrier number as the last PDCCH, Similarly, the base station may also use the PDCCH in the carrier with the smallest carrier number as the last PDCCH.

If you use the existing fields in the PDCCH to place the carrier identifier and offset, such as using the TPC field to place the carrier identifier and the HARQ process id field to place the offset, then the TPC field and the HARQ process id field in the non-last PDCCH The value placed in the field is not the real meaning of this field. Therefore, a value with the real meaning of the field must be placed in the TPC field and the HARQ process id field in the last PDCCH, so that the terminal can correctly interpret the detection according to the last PDCCH detected out PDCCH.

If you use the granularity to increase the vacated bits or add new fields to place the carrier identifier and offset, for example, use the vacated bits to place the carrier identifier and offset, you can set a special value in the vacated bits in the last PDCCH or Symbol, used to indicate that it is the last PDCCH. For example, it can be set to all 0s, special characters, or carrier identifiers of detected carriers.

The following illustrates with an example the structure of the modified PDCCH and carrier using the solution in Embodiment 1 in the case of adopting the above-mentioned first type of carrier ID placement and the second type of carrier ID placement respectively.

As shown in Figure 3, it is the case of using the vacant bits to place the carrier identifier when the first method above is used to place the carrier identifier. The aggregated carrier system consists of 5 carriers (carrier 0 to carrier 4), carrier 0 and carrier 1 , Carrier 2 and Carrier 3 have PDCCHs belonging to the same terminal, which are PDCCH_0, PDCCH_1, PDCCH_2 and PDCCH_3 respectively, wherein PDCCH_3 in Carrier 3 with the largest carrier number among the carriers with PDCCH is used as the last PDCCH in the aggregated carrier system. When using the above-mentioned first method to place carrier identifiers, the identifier of carrier 1 can be placed in PDCCH_0, the identifier of carrier 0 can be placed in PDCCH_1, the identifier of carrier 3 can be placed in PDCCH_2, and the identifier of carrier 2 can be placed in PDCCH_3. In this way, after the terminal obtains PDCCH_0 through blind detection in carrier 0, it can directly use the identifier of carrier 1 placed in PDCCH_0 to determine that the carrier that may have a PDCCH belonging to the terminal is carrier 1, and perform detection on carrier 1. When PDCCH_1 is detected, since PDCCH_1 is placed with the identifier of carrier 0, and carrier 0 is a carrier that has already been detected, the process of using the previous PDCCH to detect the next PDCCH should be stopped, and after determining that there are still undetected During PDCCH, continue to perform blind detection on undetected carriers, that is, perform blind detection on carrier 2, and when PDCCH_2 is detected, use the identifier of carrier 3 placed in PDCCH_2 to detect PDCCH_3. Further, since the PDCCH_3 is placed with the identifier of the detected carrier 2, the process of using the previous PDCCH to detect the next PDCCH is stopped, and when it is determined that there is no undetected PDCCH, the detection is stopped.

In particular, in the schematic diagram of the PDCCH structure shown in FIG. 3 , the condition for judging whether a certain PDCCH is the last PDCCH cannot be that the last PDCCH is indicated by the carrier identifier of the detected carrier.

If FIG. 3 is a case where the TPC field is used to place the carrier identifier, then a value with the true meaning of the TPC field is placed in the TPC field of PDCCH_3.

Further, considering that when the number of PDCCHs belonging to the same terminal is 3 or more, as shown in Figure 3, the identifier of carrier 0 is placed in PDCCH_1, and the identifier of carrier 1 is placed in PDCCH_0 , after PDCCH_0 is detected blindly, PDCCH_1 can be detected simply, but other undetected PDCCHs cannot be detected from PDCCH_1. In order to reduce the number of blind detections to the greatest extent, on the basis of Embodiment 1, the above-mentioned first method of placing carrier identifiers can be further limited: when the number of determined PDCCHs is at least 3, any two carriers corresponding to The carrier identity of the carrier cannot be placed in the PDCCH owned by the other party, that is, if the identity corresponding to the first carrier with the PDCCH is placed in the PDCCH owned by the second carrier, then the identity corresponding to the second carrier is set In the PDCCHs of other carriers except the first carrier among the carriers having the PDCCH.

In the further defined above-mentioned first way of placing the carrier identifier, the structure of the PDCCH and the carrier shown in Figure 3 will be changed to the situation shown in Figure 4 (it is still the case of placing the carrier identifier using the vacant bits), the terminal After PDCCH_0 is blindly detected, PDCCH_1 can be detected in carrier 1 by using the identifier of carrier 1 placed in it. 0), if it is determined that PDCCH_3 is the last PDCCH, the detection process is stopped, so that the terminal does not need to detect PDCCH in carrier 4, which reduces the number of detections.

Figure 5 (Using the vacant bits to place the carrier ID and offset) is a schematic diagram of the structure after placing the offset in the PDCCH on the basis of Figure 4. The carrier ID of carrier 1 is placed in PDCCH_0, so , also place the offset of PDCCH_1 in carrier 1 in PDCCH0.

As shown in Figure 6, when using the above-mentioned second method to place the carrier identifier, the carrier identifier is placed using the vacated bits. The aggregated carrier system consists of 5 carriers (carrier 0 to carrier 4), carrier 0 and carrier 1 , carrier 2 and carrier 3 have PDCCHs belonging to the same terminal, which are PDCCH_0, PDCCH_1, PDCCH_2 and PDCCH_3 respectively. When using the above-mentioned second method of placing carrier identifiers, the identifiers of carriers 1, 2 and 3 can be placed in PDCCH_0. In this way, after the terminal obtains PDCCH_0 through blind detection in carrier 0, it can directly use the identifiers of carriers 1, 2, and 3 placed in PDCCH_0 to determine that there may be carrier 1, carrier 2, and carrier 3 that belong to the terminal's PDCCH. The detection of carrier 1, carrier 2 and carrier 3 determines the PDCCH_1, PDCCH_2 and PDCCH_3 belonging to the terminal.

Figure 7 is a schematic diagram of the structure after placing the offset in the PDCCH on the basis of Figure 6. The carrier identifiers of carrier 1, carrier 2 and carrier 3 are placed in PDCCH_0. Therefore, PDCCH_1, PDCCH_2 and carrier identities are also placed in PDCCH0. The offsets of PDCCH_3 in carrier 1, carrier 2 and carrier 3 respectively.

After the structure of the PDCCH is modified by using the indication method of the first embodiment, the terminal can detect the PDCCH in the aggregated carrier system composed of the modified PDCCH. The process of detecting the PDCCH in the second embodiment of the present invention is shown in FIG. 8, including The following steps:

Step 201: the terminal detects its own PDCCH from a carrier in the carrier aggregation system.

Step 202: The terminal determines that there is still an undetected PDCCH belonging to the terminal in the carrier aggregation system.

If there is an undetected PDCCH belonging to the terminal in the system, that is to say, the most recently detected PDCCH belonging to the terminal is not the last PDCCH belonging to the terminal in the carrier aggregation system.

If it is determined in this step that there is no undetected PDCCH belonging to the terminal in the carrier aggregation system, that is, the most recently detected PDCCH belonging to the terminal is the last PDCCH belonging to the terminal in the carrier aggregation system, then use the last The true meaning of the TPC domain and HARQprocess id domain in a PDCCH explains the PDCCH, and the detection process ends.

Step 203: The terminal determines the carrier identity placed in the detected PDCCH.

Since the identifiers of carriers where other PDCCHs belonging to the same terminal are located are placed in the field of the PDCCH in the first embodiment, the carrier corresponding to the carrier identifier detected in step 203 probably has a PDCCH belonging to the terminal.

If the base station performs processing according to the first method of placing the carrier identifier in the first embodiment, then in this step, the terminal determines that the detected carrier identifier placed in the PDCCH is a carrier identifier of a carrier; In this step, the terminal determines that the detected carrier identifiers placed in the PDCCH are the carrier identifiers of multiple carriers.

Step 204: the terminal detects the PDCCH belonging to the terminal from the carrier corresponding to the determined carrier identifier.

Further, offsets of other PDCCHs are placed in the PDCCH involved in the first embodiment, therefore, between step 203 and step 204, the method further includes:

Step 203A: the terminal determines the offset placed in the PDCCH detected in step 203.

Then step 204 further includes: the terminal determines the carrier with the PDCCH belonging to the terminal according to the carrier identifier placed in the detected PDCCH, and then according to the determined offset placed in the detected PDCCH , detecting the PDCCH belonging to the terminal from the search space in the determined carrier.

After executing the solution from step 201 to step 204 once, if the terminal correctly detects its own PDCCH, it can jump to step 202, and when it is determined that there is still an undetected PDCCH belonging to the terminal in the carrier aggregation system, use the step 204 The obtained carrier identifier in the PDCCH continues to detect other PDCCHs until the last PDCCH is detected.

Specifically, if the carrier corresponding to the carrier identifier in the PDCCH detected in step 204 is a carrier that has already been detected, or the PDCCH detected in step 204 is illegal (that is, the PDCCH that does not belong to the terminal), that is, the terminal failed in step 204 After detecting the PDCCH belonging to itself, after step 204, the following steps may also be included:

Step 205: The terminal performs blind detection in the remaining undetected carriers, and after successfully detecting the PDCCH belonging to the terminal, jumps to step 202; otherwise, executes step 206.

Step 206: the detection process ends.

In the solution of Embodiment 2, if the base station performs processing according to the first method of placing carrier identifiers in Embodiment 1, the terminal needs to continuously jump from step 205 to step 202 until all PDCCHs are detected. Finish. If the base station performs processing according to the second method of placing carrier identifiers in Embodiment 1, the terminal determines the PDCCH of the terminal from the determined carriers after determining other carriers with PDCCHs before the main carrier in step 204 , and then jump to step 206.

Depending on the fields in the PDCCH where the carrier identifier and offset are placed, the execution scheme of step 206 is also different.

If the field for placing the carrier ID and offset in the PDCCH is an existing field, such as the TPC field for the carrier ID, and the HARQ process id field for the offset, the terminal must successfully detect the last PDCCH before the terminal can The real meaning in the TPC field and the HARQ process id field is to explain the detected PDCCH. If the last PDCCH is not successfully detected, the detected PDCCH does not contain the corresponding information in the TPC field and the HARQ process id field, that is to say The information in the detected PDCCH is incomplete, so in step 206 the detected PDCCH is discarded.

If the granularity is used to increase the vacated bits or new fields to place the carrier identifier and offset, for example, to use the vacated bits to place the carrier identifier and offset, even if the terminal does not successfully detect the last PDCCH, the detected The PDCCH contains complete information, therefore, the terminal may not discard the detected PDCCH.

Each step of the second embodiment will be described in detail below.

The specific realization scheme of step 201 is:

The terminal selects a carrier from the aggregated carrier system, and detects whether there is a PDCCH belonging to the terminal in the selected carrier through blind detection;

If there is a PDCCH belonging to the terminal, then perform subsequent steps;

Otherwise, reselect a carrier from other carriers that have not been selected in the aggregated carrier system for detection, if there is a PDCCH belonging to the terminal in other carriers, perform the next steps, if there is no PDCCH belonging to the terminal in other carriers , the detection process ends.

In the blind detection process, if the base station takes the PDCCH in the carrier with the largest carrier number as the last PDCCH, the terminal will perform blind detection in the undetected carriers in the order of carrier numbers from small to large; similarly, if The base station takes the PDCCH in the carrier with the smallest carrier number as the last PDCCH, and the terminal will perform blind detection on the undetected carriers in the descending order of the carrier numbers. For example, in the schematic structural diagram shown in FIG. 5 , the terminal firstly performs blind detection in carrier 0, and if no PDCCH belonging to the terminal is detected, performs blind detection in carrier 1.

Further, in addition to selecting carriers in a certain order, the terminal may also randomly select a carrier from the carrier aggregation system, or select a carrier from the carrier aggregation system according to the instruction information sent by the base station. If there are N PDCCHs (1≤N≤number of carriers) belonging to a certain terminal transmitted on the corresponding N carriers in a certain subframe, the N carriers must contain the main carrier, and the identity of the main carrier will be By sending the indication information to the terminal, the terminal is instructed to first detect the PDCCH in the primary carrier. If no PDCCH belonging to the terminal is detected in the main carrier, it is directly considered that there is no PDCCH belonging to the terminal in the aggregated carrier system, and the detection process ends.

Different terminals have different primary carriers, and the primary carrier of a terminal can be changed semi-statically. The conditions for setting the main carrier may include: try to make each carrier as the main carrier of the terminal, the corresponding number of terminals is the same or similar, for example, when carrier 0 is used as the main carrier of 5 terminals, the base station tries to use carrier 1 as the main carrier of 5 terminals. The main carrier of the terminal.

If the base station selects a carrier whose carrier number is neither the largest nor the smallest from the carriers with PDCCH as the main carrier, and in step 204, the terminal fails to detect the next PDCCH by using the carrier identifier and offset placed in the PDCCH of the main carrier , then when performing blind detection in step 205, the terminal still performs blind detection on carriers according to the order of carrier IDs from small to large or from large to small. Still taking the structure shown in Figure 5 as an example, assuming that carrier 1 is the main carrier, when the terminal fails to detect other PDCCHs using PDCCH_1, the terminal will perform blind detection from carrier 0. If the terminal still fails to detect other PDCCHs using PDCCH_0 During PDCCH, the terminal will continue to perform blind detection on carrier 2.

In step 202, it is necessary to use the flag mask of the PDCCH to determine whether there is an undetected PDCCH belonging to the terminal in the carrier aggregation system. The corresponding relationship between the flag mask of the PDCCH and the state of the PDCCH is shown in Table 1.

Is it the last PDCCH flag mask no <0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0> yes <0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1>

Table 1

The method for judging whether there is still an undetected PDCCH belonging to the terminal in the carrier aggregation system by using the information in Table 1 includes:

Step 1: XOR the 16-bit parity bit of the cyclic redundancy check (Cyclic Redundancy Check, CRC), the 16-bit identification of the terminal, and the first flag mask of the recently detected PDCCH, the first The flag mask is <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0>, indicating that the PDCCH does not belong to the carrier aggregation system The last PDCCH of the terminal.

If this step refers to the process of judging in step 202 whether there is still an undetected PDCCH belonging to the terminal, then the latest detected PDCCH is the PDCCH detected in step 201 .

Step 2: Perform a CRC check on the data obtained after the XOR operation. If the check is passed, it is determined that there is still an undetected PDCCH belonging to the terminal in the carrier aggregation system; otherwise, execute the third step.

Step 3: XOR the 16-bit check digit of the CRC, the 16-bit identification of the terminal, and the second flag mask of the most recently detected PDCCH, where the second flag mask is <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1> indicates that the PDCCH is the last PDCCH belonging to the terminal in the carrier aggregation system.

Step 4: Perform CRC check on the data obtained after the XOR operation, and determine that there is no undetected PDCCH belonging to the terminal in the carrier aggregation system when the check is passed.

If the CRC check fails in the fourth step, it is considered that the recently detected PDCCH is illegal.

The above method of judging whether there is still an undetected PDCCH belonging to the terminal in the carrier aggregation system can be applied to the situation where the carrier identifier and offset are placed in the existing fields, and can also be applied to the use of granularity to increase vacant bits or A new field is added to place the carrier ID and offset. Further, in the case of using granularity to increase vacant bits or new fields to place the carrier identifier and offset, it is also possible to set a special PDCCH indicating the last PDCCH in the position where the carrier identifier and offset are placed. value or symbol to determine whether the PDCCH is the last PDCCH.

In step 204, the terminal detects the PDCCH belonging to the terminal from the carrier according to the determined offset, including the following steps:

Step 1: The terminal obtains two aggregation levels corresponding to the offset determined in step 203A.

Step 2: Select the aggregation level closest to the recently detected PDCCH aggregation level from the two determined aggregation levels.

Step 3: The terminal detects the PDCCH belonging to the terminal from the selected search space of the aggregation level closest to the recently detected PDCCH aggregation level;

Step 4: If the detection of the PDCCH in the third step is successful, the detected PDCCH is the PDCCH belonging to the terminal detected from the determined carrier; otherwise, search for the other aggregation level from the two aggregation levels The PDCCH belonging to the terminal is detected in the space.

For example: if the offset is placed in the HARQ process id field of the PDCCH, a possible correspondence between the value in the HARQ process id field and the offset can be shown in Table 2.

Table 2

If the value placed in the HARQ process id field in the recently detected PDCCH is 3, it can be determined from Table 2 that: the aggregation level of the PDCCH to be detected is 1 or 2, and the offset of the PDCCH to be detected in the carrier for 3.

When the aggregation level of the recently detected PDCCH is 1, the terminal determines the carrier corresponding to the carrier identifier placed in the detected PDCCH, and first detects the carrier with the offset of 3 in the search space of the aggregation level 1 in the carrier PDCCH, if the PDCCH belongs to the terminal, continue to perform subsequent operations; otherwise, re-detect the PDCCH with the offset of 3 in the search space with aggregation level 2 in the carrier.

When the aggregation level of the recently detected PDCCH is 2, the terminal determines the carrier corresponding to the carrier identifier placed in the detected PDCCH, and first detects the carrier with the offset of 3 in the search space of the aggregation level 2 in the carrier PDCCH, if the PDCCH belongs to the terminal, continue to perform subsequent operations; otherwise, re-detect the PDCCH with the offset of 3 in the search space with aggregation level 1 in the carrier.

If the value placed in the HARQ process id field in the recently detected PDCCH is 7, it can be determined from Table 2 that the aggregation level of the PDCCH to be detected is 4 or 8, and the offset of the PDCCH to be detected in the carrier is 1.

When the aggregation level of the recently detected PDCCH is 2, the terminal determines the carrier corresponding to the carrier identifier placed in the detected PDCCH, and first detects the search for the aggregation level 4 (4 is closer to 2 than 8) in the carrier For the PDCCH with an offset of 1 in the space, if the PDCCH belongs to the terminal, continue to perform subsequent operations; otherwise, re-detect the PDCCH with an offset of 1 in the search space with an aggregation level of 8 in the carrier.

Under the same inventive concept as Embodiment 1 of the present invention, Embodiment 3 of the present invention also provides a device for indicating PDCCH in a carrier aggregation system. As shown in FIG. 9 , the device includes a location information determination module 11 and a placement module 12 , wherein: the carrier identification determination module 11 is used to determine the PDCCH belonging to a certain terminal, and determine the location information of the carrier with the PDCCH, wherein each PDCCH corresponds to a carrier, and any two PDCCHs correspond to different carriers; Module 12 is used to place the determined location information in the PDCCH, and the carrier corresponding to the location information placed in the PDCCH is different from the carrier where the PDCCH is located, and instruct the terminal to determine the carrier with the PDCCH according to the carrier identifier . The placement module 12 is further used to place a determined carrier identifier in a PDCCH. When the number of determined PDCCHs is at least 3, the carrier identifiers corresponding to any two carriers cannot be placed in the PDCCH owned by the other party. The placement module 12 is further configured to use a carrier with a PDCCH as a main carrier, and place other position information except the position information corresponding to the main carrier in the PDCCH of the main carrier among the determined position information.

The device also includes an offset determining module 13, configured to respectively determine the offset of each PDCCH in the carrier search space; the placement module 12 is further configured to place the determined offset of the PDCCH in the carrier It is placed in the PDCCH of the carrier identity corresponding to the carrier.

The PDCCH indication device in the carrier aggregation system in Embodiment 3 of the present invention may be a base station.

Under the same inventive concept as Embodiment 2 of the present invention, Embodiment 4 of the present invention also provides a device for detecting PDCCH, as shown in FIG. 10 , including a first detection module 21, a location information detection module 22 and a second detection module. 23, wherein: the first detection module 21 is used to detect a PDCCH belonging to a certain terminal from a carrier in the carrier aggregation system; the location information detection module 22 is used to determine the location information placed in the most recently detected PDCCH; the second The detection module 23 is configured to detect the PDCCH belonging to the terminal from the carrier corresponding to the location information.

The device also includes a PDCCH search module 24, configured to determine whether there is an undetected PDCCH belonging to the terminal in the carrier aggregation system, and trigger the undetected PDCCH belonging to the terminal when there is an undetected PDCCH belonging to the terminal. The location information detection module 22 described above.

The position information detection module 22 is further configured to determine that the position information placed in the most recently detected PDCCH is the position information corresponding to one carrier, or the position information corresponding to multiple carriers respectively.

This embodiment further includes an offset detection module 25, configured to determine the offset placed in the latest detected PDCCH when it is determined that there is an undetected PDCCH belonging to the terminal in the carrier aggregation system.

The second detection module 23 is further configured to trigger the PDCCH search module 24 after detecting the PDCCH belonging to the terminal from the carrier corresponding to the location information.

The second detection module 23 includes a first execution sub-module 31 and a second execution sub-module 32, wherein: the first execution sub-module 31 is used to determine the location information belonging to the terminal according to the location information determined by the location information detection module 22. The carrier of the PDCCH; the second execution submodule 32 is configured to detect the PDCCH belonging to the terminal from the search space in the carrier determined by the first execution submodule 31 according to the offset detected by the offset detection module 25 .

The second execution sub-module 32 includes an aggregation level determination sub-module 41, an aggregation level selection sub-module 42 and an operation sub-module 43, wherein: the aggregation level determination sub-module 41 is used to determine the offset according to the offset Two corresponding aggregation levels; the aggregation level selection submodule 42 is used to select the aggregation level closest to the aggregation level of the PDCCH detected recently from the two determined aggregation levels; the operation submodule 43 is used to select Detecting the PDCCH belonging to the terminal in the search space of the aggregation level closest to the aggregation level of the most recently detected PDCCH, if the detection is successful, the detected PDCCH is the PDCCH belonging to the terminal detected from the determined carrier, Otherwise, detect the PDCCH belonging to the terminal from the search space of the other aggregation level among the two aggregation levels.

The PDCCH search module 24 includes a first XOR operation submodule 33, a first syndrome submodule 34, a second XOR operation submodule 35 and a second syndrome submodule 36, wherein: the first XOR operation submodule 33 is used to perform an XOR operation on the 16-bit check digit of the CRC, the 16-bit identification of the terminal, and the first flag mask of the most recently detected PDCCH, and the first flag mask indicates that the PDCCH is not the carrier Aggregating the last PDCCH belonging to the terminal in the system; the first verification submodule 34 is used to perform CRC verification on the data obtained after the XOR operation of the first exclusive OR operation submodule 33, and if the verification passes, then determine the There is also an undetected PDCCH belonging to the terminal in the carrier aggregation system; otherwise, trigger the second exclusive OR submodule 35; the second exclusive OR operation submodule 35 is used to use the 16-bit parity bit of the CRC, the terminal The 16-bit identification of the PDCCH and the second identification mask of the most recently detected PDCCH perform an XOR operation, and the second identification mask indicates that the PDCCH is the last PDCCH belonging to the terminal in the carrier aggregation system; the second check The sub-module 36 is used to perform CRC check on the data obtained after the XOR operation of the second XOR operation sub-module 35, and when the check is passed, it is determined that there is no undetected data belonging to the terminal in the carrier aggregation system. PDCCH.

The device for detecting the PDCCH in Embodiment 4 of the present invention may be a terminal, and the location information involved is the carrier identifier of the carrier.

Embodiment 5 of the present invention also provides a communication system. As shown in FIG. 11 , the communication system includes a base station 41 and a terminal 42, wherein: the base station 41 is used to determine the PDCCH belonging to the terminal, and determine the carrier of the PDCCH location information, and place the determined location information in the PDCCH belonging to the terminal, wherein the carrier corresponding to the location information placed in the PDCCH is different from the carrier where the PDCCH is located, and each PDCCH corresponds to a carrier, and any two The carriers corresponding to each PDCCH are different; the terminal 42 is used to detect the PDCCH belonging to the terminal from a carrier in the carrier aggregation system, and determine the position information placed in the detected PDCCH, and from the position information The PDCCH belonging to the terminal is detected in the corresponding carrier.

The base station 41 is also used to place a certain position information in a PDCCH, or use a carrier with a PDCCH as the main carrier, and place other positions in the determined position information except the position information corresponding to the main carrier The information is placed in the PDCCH of the main carrier; the terminal 42 is also used to determine that the position information placed in the most recently detected PDCCH is the position information corresponding to one carrier, or the position information corresponding to multiple carriers.

The base station 41 is further configured to respectively determine the offset of each of the PDCCHs in the carrier search space, and place the determined offset of the PDCCH in the carrier into the PDCCH that places the position information corresponding to the carrier The terminal 42 is also used to determine the carrier with the PDCCH belonging to the terminal according to the position information placed in the detected PDCCH, and according to the offset placed in the detected PDCCH , detecting the PDCCH belonging to the terminal from the search space in the determined carrier.

The location information in this embodiment is the carrier identifier of the carrier.

Through the method, equipment and system provided by the embodiments of the present invention, the protocol changes of the existing LTE system and the LTE-A system are small, and have good backward compatibility; the terminal does not need to perform blind detection on all carriers, and can Using any carrier or the location information indicated by the PDCCH in the primary carrier, other carriers with the PDCCH of the terminal are determined. For example: when the location information is the carrier identifier, use the carrier identifier in the ith (i=0,..., N-2, N is not greater than the number of carriers) PDCCH to indicate the carrier where the i+1th PDCCH is located, And use the offset in the ith PDCCH to indicate the offset of the i+1th PDCCH in the search space, the terminal can directly detect the PDCCH in the determined carrier; or, use multiple carriers in the PDCCH in the main carrier Identify multiple carriers with terminal PDCCH respectively, which greatly reduces the number of times of blind detection. With the application of the present invention, in addition to the blind detection required by LTE on the main carrier, the terminal can only perform blind detection twice on the remaining carriers, which reduces the complexity and power consumption of the terminal.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (27)

1. An indication method of a physical downlink control channel PDCCH in a carrier aggregation system, characterized in that the method comprises the following steps: The base station determines the PDCCH belonging to a certain terminal, and determines the position information of the carrier having the PDCCH, wherein each PDCCH corresponds to a carrier, and the carriers corresponding to any two PDCCHs are different; The base station separately determines the offset of each PDCCH in the carrier search space; The base station places the determined location information in the PDCCH belonging to the terminal, places the determined offset of the PDCCH in the carrier in the PDCCH that places the location information corresponding to the carrier, and the location information placed in the PDCCH corresponds to The carrier of the PDCCH is different from the carrier of the PDCCH, which is used to instruct the terminal to determine the carrier with the PDCCH according to the location information and according to the offset placed in the PDCCH, from the determined carrier with the PDCCH The PDCCH belonging to the terminal is detected in the search space in . 2. The method according to claim 1, wherein the base station places the determined location information in the PDCCH belonging to the terminal, comprising: The base station places the determined location information in a PDCCH. 3. The method of claim 2, wherein When the determined number of PDCCHs belonging to the terminal is at least 3, if the location information corresponding to the first carrier with the PDCCH is placed in the PDCCH with the second carrier, then the second carrier corresponds to The location information of the PDCCH is placed in the PDCCHs of other carriers except the first carrier among the carriers having the PDCCH. 4. The method according to claim 1, wherein placing the determined location information in the PDCCH belonging to the terminal comprises: The base station uses a carrier with the PDCCH as the main carrier, and places other position information except the position information corresponding to the main carrier in the PDCCH of the main carrier among the determined position information. 5. The method according to claim 1, wherein the determined location information is placed in the first special field of the PDCCH, and the first special field is a transmission power control TPC field in the PDCCH or a resource in the PDCCH Allocation field, or newly added field in PDCCH, or DCIFormat field in PDCCH. 6. The method according to claim 1, wherein the determined offset of the PDCCH in the carrier is placed in the second special field of the PDCCH corresponding to the position information of the carrier; If the DCI format of the PDCCH is 1, 1A, 1B, 1C, 1D, 2 or 2A, the second special field is the HARQ process id field in the PDCCH or a newly added field in the PDCCH; If the DCI format of the PDCCH is 0, the second special field is the Cyclic shift for DM RS field of the demodulation reference signal in the PDCCH or a newly added field in the PDCCH. 7. The method according to any one of claims 1-6, wherein the location information of the carrier is a carrier identifier of the carrier. 8. A method for detecting a PDCCH according to the position information determined by the indication method according to claim 1, wherein the method for detecting a PDCCH comprises the following steps: The terminal detects the PDCCH belonging to the terminal from a carrier in the carrier aggregation system; The terminal determines the location information placed in the detected PDCCH; The terminal determines an offset placed in the detected PDCCH; The terminal determines a carrier having a PDCCH belonging to the terminal according to the position information placed in the detected PDCCH; The terminal detects the PDCCH belonging to the terminal from the determined search space in the carrier according to the offset placed in the detected PDCCH. 9 . The method for detecting a PDCCH according to claim 8 , wherein the detected PDCCH is placed with location information corresponding to one carrier, or location information corresponding to multiple carriers. 10 . 10. The method for detecting PDCCH according to claim 8, wherein, after the terminal detects the PDCCH belonging to the terminal from the carrier corresponding to the location information, the method for detecting the PDCCH further comprises the following steps: If the terminal fails to detect the PDCCH belonging to the terminal from the carrier corresponding to the location information, the terminal judges whether there is an undetected PDCCH belonging to the terminal in the carrier aggregation system; If so, the terminal selects a carrier from undetected carriers, and detects the PDCCH in the selected carrier through blind detection; Otherwise, stop testing. 11. The method for detecting PDCCH according to claim 8, wherein the terminal detects the PDCCH belonging to the terminal from a carrier in the carrier aggregation system, comprising the following steps: The terminal selects a carrier from the carrier aggregation system, and detects the PDCCH on the selected carrier through blind detection. 12. The method for detecting PDCCH according to claim 11, wherein the terminal selects a carrier from the carrier aggregation system, comprising: The terminal randomly selects a carrier from the carrier aggregation system, or determines the main carrier from the carrier aggregation system according to the instruction information issued by the base station, and uses the determined main carrier as a selected carrier, or, according to the location information, from small to large Or select a carrier in descending order. 13. The method for detecting PDCCH according to claim 8, wherein the terminal detects the PDCCH belonging to the terminal from the determined carrier according to the determined offset, comprising the following steps: The terminal determines two aggregation levels corresponding to the offset according to the offset; selecting the aggregation level closest to the recently detected PDCCH aggregation level from the two determined aggregation levels; The terminal detects the PDCCH belonging to the terminal from the selected search space of the aggregation level closest to the recently detected PDCCH aggregation level; If the detection is successful, the detected PDCCH is the PDCCH belonging to the terminal detected from the determined carrier; Otherwise, detect the PDCCH belonging to the terminal from the search space of the other aggregation level among the two aggregation levels. 14. The method for detecting a PDCCH according to claim 10, wherein determining whether there is an undetected PDCCH belonging to the terminal in the carrier aggregation system comprises the following steps: Perform an XOR operation on the 16-bit parity bit of the cyclic redundancy check CRC, the 16-bit identification of the terminal, and the first flag mask of the most recently detected PDCCH, and the first flag mask indicates that the PDCCH is not the The last PDCCH belonging to the terminal in the carrier aggregation system; Performing a CRC check on the data obtained after the XOR operation, and if the check is passed, it is determined that there is still an undetected PDCCH belonging to the terminal in the carrier aggregation system; otherwise, performing an XOR operation on the 16-bit parity bit of the CRC, the 16-bit identification of the terminal, and the second flag mask of the most recently detected PDCCH, where the second flag mask indicates that the PDCCH is in the carrier aggregation system The last PDCCH belonging to the terminal; The CRC check is performed on the data obtained after the XOR operation, and when the check is passed, it is determined that there is no undetected PDCCH belonging to the terminal in the carrier aggregation system. 15. The method for detecting a PDCCH according to any one of claims 8 to 14, wherein the location information is a carrier identifier of a carrier. 16. A device for indicating PDCCH in a carrier aggregation system, characterized in that the device includes: A position information determining module, configured to determine a PDCCH belonging to a certain terminal, and determine the position information of a carrier having the PDCCH, wherein each PDCCH corresponds to a carrier, and any two PDCCHs correspond to different carriers; an offset determination module, configured to determine the offset of each PDCCH in the carrier search space; a placement module, configured to perform the following operations: place the determined location information in the PDCCH belonging to the terminal, place the determined offset of the PDCCH in the carrier into the PDCCH in which the location information corresponding to the carrier is placed, And the carrier corresponding to the position information placed in the PDCCH is different from the carrier where the PDCCH is located, wherein the operation is used to instruct the terminal to determine the carrier with the PDCCH according to the position information and according to the carrier placed in the PDCCH The offset is used to detect the PDCCH belonging to the terminal from the determined search space of the carrier having the PDCCH. 17. The apparatus of claim 16, wherein The placement module is also used to place a location information in a PDCCH; or, use a carrier with a PDCCH as the main carrier, and use other location information in the determined location information except the location information corresponding to the main carrier Placed in the PDCCH of the main carrier. 18. The device according to claim 16 or 17, wherein the location information is a carrier identity of a carrier. 19. A device for detecting PDCCH according to the location information determined by the pointing device of claim 16, characterized in that, the device for detecting PDCCH includes a first detection module, a location information detection module, an offset detection module and a second A detection module, the second detection module includes a first execution submodule and a second execution submodule, wherein: A first detection module, configured to detect a PDCCH belonging to a certain terminal from a carrier in the carrier aggregation system; A location information detection module, configured to determine the location information placed in the most recently detected PDCCH; An offset detection module, configured to determine the offset placed in the most recently detected PDCCH when it is determined that there is an undetected PDCCH belonging to the terminal in the carrier aggregation system; The second detection module is configured to detect the PDCCH belonging to the terminal from the carrier corresponding to the location information, specifically including: The first execution submodule is used to determine the carrier with the PDCCH belonging to the terminal according to the location information determined by the location information detection module; The second execution submodule is configured to detect the PDCCH belonging to the terminal from the search space in the carrier determined by the first execution submodule according to the offset detected by the offset detection module. 20. The device for detecting PDCCH according to claim 19, wherein the device for detecting PDCCH further comprises: A PDCCH search module, configured to determine whether there is an undetected PDCCH belonging to the terminal in the carrier aggregation system, and trigger the location information detection module when there is an undetected PDCCH belonging to the terminal. 21. The device for detecting PDCCH according to claim 19, characterized in that, The position information detection module is further configured to determine that the position information placed in the most recently detected PDCCH is the position information corresponding to one carrier, or the position information corresponding to multiple carriers respectively. 22. The device for detecting PDCCH according to claim 20, characterized in that, The second detection module is further configured to trigger the PDCCH search module after successfully detecting the PDCCH belonging to the terminal from the carrier corresponding to the location information. 23. The device for detecting PDCCH according to claim 20, wherein the PDCCH search module comprises: The first exclusive-or operation submodule is used to perform an exclusive-or operation on the 16-bit check digit of the CRC, the 16-bit identification of the terminal, and the first flag mask of the most recently detected PDCCH, the first flag mask Indicates that the PDCCH is not the last PDCCH belonging to the terminal in the carrier aggregation system; The first verification submodule is used to perform CRC verification on the data obtained after the XOR operation of the first exclusive OR operation submodule. If the verification is passed, it is determined that there are still undetected data belonging to the carrier aggregation system in the carrier aggregation system. the PDCCH of the terminal; otherwise, trigger the second XOR submodule; The second exclusive OR operation submodule is used to perform an exclusive OR operation on the 16-bit check digit of the CRC, the 16-bit identification of the terminal, and the second flag mask of the PDCCH detected recently, and the second flag mask Indicates that the PDCCH is the last PDCCH belonging to the terminal in the carrier aggregation system; The second verification submodule is used to perform CRC verification on the data obtained after the XOR operation of the second exclusive OR operation submodule, and when the verification is passed, it is determined that there is no undetected data belonging to the carrier aggregation system in the carrier aggregation system. The PDCCH of the terminal. 24. The device for detecting PDCCH according to claim 21, wherein the second execution submodule comprises: An aggregation level determination submodule, configured to determine two aggregation levels corresponding to the offset according to the offset; an aggregation level selection submodule, configured to select the aggregation level closest to the aggregation level of the most recently detected PDCCH from the two determined aggregation levels; The operation submodule is used to detect the PDCCH belonging to the terminal from the selected search space of the aggregation level closest to the aggregation level of the recently detected PDCCH. If the detection is successful, the detected PDCCH is from the determined carrier. detected PDCCH belonging to the terminal, otherwise, aggregated from the two The PDCCH belonging to the terminal is detected in the search space of another aggregation level in the level. 25. The device for detecting a PDCCH according to any one of claims 19-24, wherein the location information is a carrier identifier of a carrier. 26. A communication system, characterized in that the system includes a base station and a terminal, wherein the base station includes a position information determination module, an offset determination module, and a placement module, and the terminal includes a first detection module, a position information A detection module, an offset detection module and a second detection module, the second detection module includes a first execution submodule and a second execution submodule: The position information determination module is configured to determine the PDCCH belonging to the terminal, and determine the position information of the carrier having the PDCCH, wherein each PDCCH corresponds to a carrier, and any two PDCCHs correspond to different carriers; The offset determination module is configured to respectively determine the offset of each PDCCH in the carrier search space; The placement module is configured to place the determined location information in the PDCCH belonging to the terminal, and place the determined offset of the PDCCH in the carrier into the PDCCH in which the location information corresponding to the carrier is placed, wherein , the carrier corresponding to the location information placed in the PDCCH is different from the carrier where the PDCCH is located; The first detection module is configured to detect a PDCCH belonging to the terminal from a carrier in the carrier aggregation system; The location information detection module is configured to determine the location information placed in the detected PDCCH; The offset detection module is configured to determine the offset placed in the most recently detected PDCCH when it is determined that there is an undetected PDCCH belonging to the terminal in the carrier aggregation system; The second detection module is configured to detect the PDCCH belonging to the terminal from the carrier corresponding to the location information, wherein: The first execution submodule is configured to determine a carrier having a PDCCH belonging to the terminal according to the position information placed in the detected PDCCH; The second execution submodule is configured to detect the PDCCH belonging to the terminal from the determined search space in the carrier according to the offset placed in the detected PDCCH. 27. The system of claim 26, wherein: The placement module is also used to place a certain location information in a PDCCH, or use a carrier with a PDCCH as the main carrier, and use the determined location information, other than the location information corresponding to the main carrier The location information is placed in the PDCCH of the main carrier; The position information detection module is further configured to determine that the position information placed in the most recently detected PDCCH is the position information corresponding to one carrier, or the position information corresponding to multiple carriers respectively.

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