CN102882644B - The check processing of Downlink Control Information, detection method and device - Google Patents

Abstract

The present invention provides a detection processing, detection method and device of downlink control information, the detection processing method of downlink control information includes: for each group respectively configure a dedicated group A group-specific search space, wherein the group-specific search space is identified by the trunk radio network temporary identifier T-RNTI; in the configured group-specific search space, a specified degree of aggregation is assigned to the physical downlink control channel PDCCH, so that the cluster terminal follows the specified The aggregation degree performs blind detection on the PDCCH in the group-specific search space. Adopting the technical scheme of the present invention solves the problem that there is no technical means for detecting the PDCCH masked by T-RNTI in the related art, so as to meet the downlink control information detection requirement when the trunking service and common service coexist in the trunking system.

Description

Detection processing, detection method and device of downlink control information

technical field

The present invention relates to the communication field, in particular to a detection process, detection method and device of downlink control information.

Background technique

Trunking Communication System (Trunking Communication System) is a dedicated wireless communication system for specific industry applications developed to meet the command and dispatch needs of industry users. In the system, a large number of wireless users share a small number of wireless channels, and the main application is command and dispatch. Multi-purpose, high-performance wireless communication system. The trunking communication system has a wide range of application markets in the fields of government departments, public safety, emergency communications, electric power, civil aviation, petrochemical and military.

The trunking communication system has experienced a development process similar to that of the cellular mobile communication system. Among them, the first-generation trunking system is an analog trunking communication system, which mainly supports voice communication, and has been gradually eliminated by the market. The second-generation trunking system is a narrowband digital trunking communication system, which emerged in the 1990s and began to be deployed in my country around 2004. It is currently the most widely used trunking communication system in China. The digital trunking communication system supports voice and low-speed data (up to 28.8kbps) communication. The representative system is the Terrestrial Trunked Radio (TETRA) system defined by the European Telecommunications Standards Institute (ETSI). The integrated digital enhanced network (Integrated Digital Enhanced Networks, referred to as iDEN) system of Motorola in the United States, the open trunking structure (Global Open Trunking Architecture, referred to as GoTa) system developed by ZTE Corporation based on CDMA1X, and the GT800 system developed based on GSM .

Judging from the current development of the trunking communication system, the development of the trunking communication system is far behind the development of the public cellular system, and its technological innovation and industrial chain are not yet complete. In terms of data transmission capability and multimedia service support capability, the current digital narrowband trunking communication system is still relatively backward. For example, the broadband integrated digital enhanced network (Wide-iDEN, referred to as WiDEN) launched by the iDEN system after improving the time slot and modulation method increases the peak transmission rate to 384kbps; TETRA Enhanced Data Service (TETRA Release 2 Enhanced Data Service, referred to as TEDS), ideally can support a peak transmission rate of no more than 700kbps; none of them have reached the order of Mbps. In addition, in terms of spectrum utilization and coverage, the existing digital trunking systems cannot meet the requirements well.

With the rapid development of mobile Internet and the large-scale construction of global wireless cities, broadband has become the development trend of the entire wireless communication. Correspondingly, the trunking communication system will also develop in the direction of system IP, business diversification, data broadband, and terminal multi-mode technology. From the perspective of specific applications, it is mainly reflected in high-speed data, video, and built-in A variety of applications based on this, including mobile office, multimedia cluster scheduling, video surveillance, urban emergency linkage, etc.

The Long Term Evolution (LTE) system formulated by the International Standards Organization's 3rd Generation Partnership Project (3GPP) has become the mainstream standard for next-generation cellular communications and has been recognized worldwide. With the extensive support of operators and communication manufacturers, the industry now has relatively mature LTE system equipment and LTE terminals put into commercial use, and has gradually been deployed on a large scale around the world. The LTE standard adopts advanced wireless transmission technologies such as Orthogonal Frequency Division Multiplexing (OFDM for short), Multiple Input Multiple Output (MIMO for short), flat network results and an all-IP system architecture, and supports Maximum system bandwidth of 20MHz, downlink peak rate over 300Mbps and shorter transmission delay.

Considering the above-mentioned advantages of the LTE standard and the requirements of the broadband trunking communication system, it is natural for the industry to propose a digital trunking system based on the LTE technology. In this trunking system, the trunking service will be carried in the packet-switched (PS) domain, which can fully realize the sharing of service channels, greatly improve resource utilization, and thus reduce the operating cost of the system. On the other hand, since the LTE technology adopts an all-IP flat network architecture, and the base station is directly connected to the core network, the internal signaling interaction on the network side during the call establishment process is reduced, and the call establishment time is also shortened, which can meet the needs of the trunking system. Based on mature LTE technology, relying on the rapid transformation of relatively mature LTE system equipment and terminal industry chain in the industry, it is conducive to the rapid launch of broadband trunking communication systems to meet the growing market demand for trunking communications. For general enterprises, logistics, transportation and other departments, in order to reduce costs and reflect economic benefits, public trunking communication systems that share frequency resources and network infrastructure are generally used, and trunking services are provided on public mobile communication systems. Command and dispatch function. On the other hand, as frequency resources become increasingly tight, how to improve frequency utilization, realize optimal allocation of resources, and strengthen rapid response and anti-risk capabilities for emergencies and emergencies has become a top priority. In this case, the common network of digital trunking and public cellular network will become the development direction of future digital trunking communication. This means that in addition to supporting trunking services, the broadband trunking communication system must also be compatible with the original common point-to-point services of LTE.

In the LTE standard, the point-to-multipoint transmission technology such as eMBMS (enhanced broadcast/multicast multimedia technology) will not be fully defined until the specification of 3GPP Release 9. At present, the industry supports mature system equipment and terminals of eMBMS Also relatively few. Therefore, the LTE technology considered at this stage should still be based on point-to-point communication. However, the trunking downlink service is a point-to-multipoint multicast (multicast) service, so it is necessary to add a new logical channel on the basis of the original LTE channel, as shown in Figure 1.

The newly added logical channels include:

Trunking Paging Channel (TPCH): used to paging trunk users to quickly establish trunk service transmission;

Trunking Dedicated Control Channel (TDCCH): used to carry trunking control signaling for downlink speaking users or single call users;

Trunking Global Control Channel (TGCCH): used to carry control signaling for downlink trunking services of listening users in a certain group;

Trunking Global Traffic Channel (TGTCH): used to carry downlink trunking services for users in a certain group.

In the LTE standard, downlink services are generally mapped to a Physical Downlink Shared Channel (PDSCH for short) for transmission. The time length of the PDSCH channel is a subframe (subframe) with a length equal to 1ms, also called a transmission time interval (Transmission Time Interval, TTI for short). In each subframe, corresponding to the PDSCH is a Physical Downlink Control Channel (PDCCH for short). Similarly, all uplink services are also mapped to the Physical Uplink Shared Channel (PUSCH for short) for transmission, and generally there is a PDCCH corresponding to the PUSCH. Downlink Control Information (DCI for short) is carried on the PDCCH. These DCIs have different formats (formats) and correspond to different control information contents, for example:

DCI format 0: It can be used to indicate information such as PUSCH resources, also known as "uplink grant" (uplink grant);

DCI format 1A: It can be used to indicate information such as PDSCH resources, also known as "downlink assignment".

According to the downlink channel conditions (the distance between the terminal and the base station, the size of the interference from neighboring cells, etc.), in order to provide corresponding channel coding protection and ensure that the PDCCH channel can be successfully detected at the terminal side with a high probability, DCI can use different The channel coding code rate is finally mapped to resources of different sizes. In the LTE system, four types of PDCCH resource sizes are defined, namely 1, 2, 4 and 8 Control Channel Elements (CCE for short), where each CCE contains 72 coded bits of information. The number of CCEs occupied by the PDCCH is also called aggregation level. The higher the degree of aggregation, the stronger the encoding protection provided, but the more resources it takes up.

Both LTE uplink and downlink adopt dynamic scheduling or semi-persistent scheduling (SPS for short), which provides a high degree of flexibility. Correspondingly, the PDCCH control channel corresponding to PDSCH and PUSCH is also allocated in a common "control region" (control region). This control region is generally composed of the first 1 to 4 OFDM symbols at the beginning of each subframe. Since there are different types of logical channels and transport channels in the system, such as system messages, paging, random access responses, user-specific uplink and downlink services, and uplink power control commands, etc., in order to distinguish, define for each PDSCH and PUSCH An associated 16-bit radio network temporary identifier (Radio Network Temporary Identifier, RNTI for short).

In one subframe, there may be multiple PDCCHs that need to be sent at the same time. In order to reduce control channel overhead in the LTE system, the positions of these PDCCH channels in the above-mentioned control region are dynamically allocated. In this way, in order to receive DCI, the terminal must first search in this control area. In the LTE system, in order to reduce the processing complexity of the terminal searching for the PDCCH in the common area, so as to achieve the purpose of reducing processing delay and/or reducing power consumption, two "PDCCH search spaces" are respectively defined in the control area, That is, the common search space (common search space) and the UE-specific search space (UE-specific search space). Corresponding to each DCI type, the terminal only needs to search in the corresponding search space, that is, in the control area, corresponding to each starting position where PDCCH is allowed to appear, try to process according to the corresponding aggregation degree in turn (including: deinterleaving , De-rate matching, channel decoding, etc.), and use the aforementioned RNTI value to de-masking the CRC part. If the CRC check is correct, a PDCCH is detected, and the contained DCI information is analyzed. The above process is also called a PDCCH blind detection (PDCCH blind detection) process. Note that the common search space only occupies a space of up to 16 CCEs, and is generally used to carry PDCCH transmissions for all users or non-specific users in the cell, such as system broadcast messages and paging messages; however, in order to improve flexibility In order to improve the spectrum efficiency, if the common search space is vacant, some PDCCHs for specific users may also be arranged in the common search space. Therefore, even for the user-specific information masked by the C-RNTI, in addition to searching in the UE-specific search space, it is also necessary to perform corresponding PDCCH detection in the common search space.

According to the definition of the LTE standard, for each DCI format in each subframe, the terminal needs to perform channel decoding (Viterbi decoding) at most 44 times.

In the control area, the public search space is equal to 0 from the CCE offset address; while the UE-specific search space, the CCE offset address corresponding to each aggregation degree is generated by a hash function (Hashing function), and changes by subframe. The initial value of the hash function is equal to the C-RNTI allocated when the terminal establishes the RRC connection. Corresponding to each terminal, since the C-RNTI is its unique identifier in the network, it can be guaranteed that the UE-specific search space defined for each terminal is different in each subframe. See Figure 2 for an example. This can ensure that the probability of conflict between UE-specific search spaces of different terminals is as low as possible, thereby ensuring a high spectrum utilization rate for control channel transmission, and also providing flexibility when the network allocates PDCCHs to different terminals.

The aforementioned four newly added trunking logical channels are all mapped to the DL-SCH transmission channel, and then mapped to the PDSCH physical channel for transmission on the air interface. For these four newly added trunking logical channels, existing or newly defined RNTIs are used to distinguish them according to their characteristics. in:

TPCH channel: In essence, it is similar to the mechanism related to LTE's original paging channel (Paging Channel, referred to as PCH). The PDCCH masked by a newly defined cluster paging RNTI (TP-RNTI) performs PDSCH resource indication; through The actual staggering of each terminal's need to receive normal paging and cluster paging can avoid the possibility that the terminal needs to detect the PDCCH masked by P-RNTI and TP-RNTI at the same time in the same subframe;

TDCCH channel: It is still point-to-point transmission in essence, so the PDCCH covered by LTE's original C-RNTI or SPSC-RNTI is still used for PDSCH resources, where C-RNTI is an identifier assigned to the user by the network when the user establishes an RRC connection;

TGCCH and TGTCH channels: essentially point-to-multipoint transmission, PDSCH resource indication is performed by a group of newly defined cluster RNTI (T-RNTI) masked PDCCH, where the network reserves a batch in the RNTI space (for example: 4096) RNTI values are used as T-RNTI, and a T-RNTI is assigned to each newly created group, and all listening users in this group use this T-RNTI to receive corresponding downlink cluster multicast services.

For simplicity of description, the TGCCH and TGTCH are collectively referred to as "trunk downlink multicast channel" here. In some other literature, it is possible to use different names for these trunking downstream channels, but the essence of their point-to-multipoint transmission is the same.

In this patent, trunking group: as the name implies, trunking communication is to gather multiple groups of users in the instrument for communication. The biggest feature of trunking communication is that the voice communication adopts PTT ((Push ToTalk), which is connected in a push-to-talk manner. The mode of operation is mainly simplex and half-duplex, and the channel dynamic allocation method is mainly used, and users have different priority levels and special functions, and can respond to all calls during communication.

In order to enable the trunking terminal to receive the trunking downlink multicast channel and continue to maintain the original LTE normal service, it is hoped that the terminal will add the masking of the above T-RNTI on the basis of the existing PDCCH blind detection process. Detection of PDCCH. How to define the search space for the PDCCH masked by the T-RNTI and define the related terminal search method is one of the key issues to be solved in the trunking system based on LTE. Moreover, in order to support multiple groups in the network at the same time, there may be multiple T-RNTIs at the same time, relying only on the PDCCH capacity provided by the common search space (only 2 PDCCHs with an aggregation degree equal to 8, or 4 PDCCHs with an aggregation degree equal to 4 channel) is far from enough, and no effective solution has been proposed for the above-mentioned problems of related technologies.

Contents of the invention

The present invention provides a detection process, detection method and device for downlink control information, which is used to solve the problem that there is no technical means to detect the PDCCH masked by T-RNTI in the related art, and when there are multiple T-RNTIs, Technical problems such as insufficient PDCCH capacity provided by the existing common search space.

In order to achieve the above purpose, according to the first aspect of the present invention, a method for detecting and processing downlink control information is provided, and the following technical solutions are adopted:

The method for detecting and processing downlink control information is used for a network-side entity, including: configuring a dedicated group-specific search space for each group for a cluster downlink multicast channel in a broadband trunking communication system, wherein the group-specific The search space is identified by the cluster radio network temporary identifier T-RNTI; in the configured group-specific search space, a physical downlink control channel PDCCH is assigned a specified degree of aggregation, so that the cluster terminal performs a search for the group according to the specified degree of aggregation. The PDCCH in the dedicated search space performs blind detection.

Further, allocating a designated aggregation degree for the physical downlink control channel PDCCH includes: assigning a designated aggregation degree to each physical downlink control channel PDCCH masked by the T-RNTI, wherein the designated aggregation degree is related to the cell radio There is no intersection between the network temporary identifier C-RNTI and the PDCCH aggregation degree masked by the semi-persistently assigned cell radio network identifier SPSC-RNTI.

Further, after assigning a specified aggregation degree to each physical downlink control channel PDCCH masked by the T-RNTI, it also includes: on the subframe that requires the cluster terminal to receive the cluster downlink multicast channel, from the Select the PDCCH aggregation degree masked by C-RNTI and SPSC-RNTI from the aggregation degrees other than the above-mentioned specified aggregation degrees.

Further, the group-specific search space is configured in the following manner: in the UE-specific search space, a specified search range is divided as the group-specific search space.

Further, after allocating a specified aggregation degree to each physical downlink control channel PDCCH masked by the T-RNTI to the T-RNTI, it also includes: sending a system broadcast message or a specified signaling during the group downlink connection establishment process to The cluster terminal issues the specified aggregation degree.

Further, the method for detecting and processing downlink control information further includes: sending indication information to the cluster terminal, where the indication information is used to indicate the subframe that needs to receive the cluster downlink multicast channel.

According to a second aspect of the present invention, a method for detecting downlink control information is provided, and the following technical solution is adopted:

The method for detecting downlink control information is used for a trunking terminal, including: receiving a designated aggregation degree from a network side entity, wherein the designated aggregation degree is configured by the network side entity for a cluster downlink multicast channel in a broadband trunking communication system. In the group-specific search space, the specified aggregation degree allocated for the physical downlink control channel PDCCH, and the group-specific search space is identified by the cluster radio network temporary identifier T-RNTI; according to the specified aggregation degree, the group Blind detection is performed on the PDCCH in the group-specific search space.

Further, the specified aggregation degree is the aggregation degree assigned by the network side entity to each physical downlink control channel PDCCH masked by the T-RNTI, and the specified aggregation degree is related to the cell wireless network temporary identifier C- There is no intersection between the PDCCH aggregation degrees masked by the RNTI and the SPSC-RNTI.

According to a third aspect of the present invention, a device for detecting and processing downlink control information is provided, and the following technical solution is adopted:

The detection and processing device of the downlink control information is located in the network side entity, including: a configuration module for configuring a dedicated group-specific search space for each group for the cluster downlink multicast channel in the broadband cluster communication system, Wherein, the group-specific search space is identified by the cluster radio network temporary identifier T-RNTI; the allocation module is used to allocate a specified aggregation degree for the physical downlink control channel PDCCH in the configured group-specific search space, wherein the cluster The terminal performs blind detection on the PDCCH in the group-specific search space according to the specified aggregation degree.

According to a fourth aspect of the present invention, a detection device for downlink control information is provided, and the following technical solution is adopted:

The detection device for downlink control information is located in the trunking terminal and includes: a receiving module for receiving a specified aggregation degree from the network side entity, wherein the specified aggregation degree is the network side entity for the cluster downlink group in the broadband trunking communication system broadcast channel, in the configured group-specific search space, the degree of aggregation allocated for the physical downlink control channel PDCCH, and the group-specific search space is identified by the cluster radio network temporary identifier T-RNTI; the detection module is used to follow The specified aggregation degree performs blind detection on the PDCCH in the group-specific search space.

Through the present invention, by adopting the technical means of configuring a dedicated group-specific search space for each group, it is solved that in the related art, there is no technical means for detecting the PDCCH masked by T-RNTI, and the existing When there are multiple T-RNTIs, there are technical problems such as insufficient PDCCH capacity provided by the existing public search space, so as to meet the downlink control information detection requirements when trunking services and common services coexist in the trunking system.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

FIG. 1 is a schematic diagram of a newly added logical channel of a cluster and a mapping relationship with a transmission channel and a physical channel according to related technologies;

FIG. 2 is an example of a PDCCH common search space and a UE-specific search space defined in an LTE system according to the related art;

3 is a flowchart of a method for detecting and processing downlink control information according to Embodiment 1 of the present invention;

FIG. 4 is a structural block diagram of an apparatus for detecting and processing downlink control information according to Embodiment 1 of the present invention;

5 is a flowchart of a method for detecting downlink control information according to Embodiment 2 of the present invention;

FIG. 6 is a structural block diagram of an apparatus for detecting downlink control information according to Embodiment 2 of the present invention;

FIG. 7 is a schematic diagram of an example of a PDCCH common search space, a UE-specific search space and a group-specific search space according to Embodiment 3 of the present invention;

FIG. 8 is a flowchart of a terminal performing PDCCH detection in a UE-specific search space and a group-specific search space simultaneously according to Embodiment 3 of the present invention.

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways defined and covered by the claims.

Considering the technical problems in the related art, such as insufficient PDCCH capacity provided by the existing public search space when multiple T-RNTIs exist at the same time, related solutions are provided below in combination with embodiments, and are now described in detail.

Fig. 3 is a flowchart of a method for detecting and processing downlink control information according to Embodiment 1 of the present invention. This method is applied to network-side entities, as shown in Figure 3, the method includes the following processing steps:

Step S302, for the cluster downlink multicast channel in the broadband trunking communication system, configure a dedicated group-specific search space for each group, wherein the group-specific search space is identified by T-RNTI;

Step S304, assigning a specified aggregation degree to the PDCCH in the configured group-specific search space, so that the trunking terminal performs blind detection on the PDCCH in the group-specific search space according to the specified aggregation degree.

Through the above processing steps, regardless of the situation where one or more T-RNTIs exist, the above processing steps can be used to perform blind detection on the PDCCH, especially for the situation where there are multiple T-RNTIs, it can solve the problem of existing The technical problem of insufficient PDCCH capacity provided by the public search space, so as to meet the downlink control information detection requirements when common services and cluster services coexist in the trunking system.

If the process in step S302 and step S304 is adopted, since a new set of dedicated search space is added, however, based on the existing technology of LTE, only public search space and UE-specific search space are usually considered in terminal design, and the corresponding support Up to 44 Viterbi decoding processes. If the terminal needs to add a new dedicated search space in order to support the trunking system, it will undoubtedly increase the processing burden of the PDCCH blind detection of the terminal, resulting in increased complexity and/or increased power consumption. Moreover, if the PDCCH blind detection processing time needs to be increased, it may mean that more buffers are required to store the received data of each subframe, because the PDSCH decoding process cannot be started before the DCI information analysis on the PDCCH is completed. In addition, the preparation time for PUSCH transmission processing is also reduced. Therefore, it may also have a huge impact on the software and hardware timing design of the terminal. If the impact on terminal modification is too great, it will result in too few available terminal types, which will adversely affect the successful commercial use of the trunking system.

In short, for the newly added point-to-multipoint cluster downlink multicast channel in the cluster, on the one hand, the terminal needs to support PDCCH detection with T-RNTI masking in the group-specific space, and on the other hand, it must be considered The increased complexity of terminal PDCCH blind detection and the amount of modification required. In order to quickly launch terminals supporting LTE-based broadband trunking communication systems, the above-mentioned contradictions must be resolved, taking into account the requirements of the trunking and the processing capabilities and maturity of the terminals. In order to solve the above contradiction, in this embodiment, the network side entity assigns a specified aggregation degree to each physical downlink control channel PDCCH masked by T-RNTI, where the specified aggregation degree is related to the cell radio network temporary identifier C-RNTI and half There is no overlap between the PDCCH aggregation degrees masked by the SPSC-RNTI of the continuously assigned cell wireless network identifier.

According to existing LTE-related specifications, the terminal needs to search for PDCCHs with aggregation degrees of 1, 2, 4, and 8 in the UE-specific search space in each subframe. Now in order to support cluster applications, for example, if the network specifies an aggregation degree of 4 for the PDCCH masked by T-RNTI, then when the terminal searches for a PDCCH in the original UE-specific search space, it will avoid the PDCCH with an aggregation degree of 4, and only Search for PDCCHs with aggregation degrees of 1, 2, and 8 respectively; then, the terminal uses the vacant PDCCH search resources in the subframe for PDCCHs with aggregation degrees of 4 to search for PDCCHs with T-RNTI masking. In this way, the overall PDCCH search complexity of the terminal does not increase. In this manner, the terminal only needs to change when allocating PDCCH search hardware resources for different aggregation degrees, which is relatively simple.

Correspondingly, after the network side entity assigns a specified aggregation degree to the physical downlink control channel PDCCH masked by T-RNTI for each T-RNTI, on the subframe that requires the cluster terminal to receive the cluster downlink multicast channel, start from the specified aggregation Select the PDCCH aggregation degree masked by C-RNTI and SPSC-RNTI from the aggregation degrees other than the degree.

In this embodiment, the group-specific search space is configured in the following manner: in the UE-specific search space, a specified search range is divided as the group-specific search space. It can be expressed as the following process:

In the original UE-specific search space, for the part of "DCI format 1 or 1B or 1D or 2 or 2A or 2B", it is possible to delineate the PDCCH search dedicated to the group-specific search space, so that it still does not increase the number of terminals The number of times of Viterbi decoding in the PDCCH blind detection process.

In this embodiment, after the network-side entity assigns a specified aggregation degree to the Physical Downlink Control Channel (PDCCH) masked by each T-RNTI with respect to the T-RNTI, the network-side entity also needs to pass a system broadcast message or group downlink connection establishment process The specified signaling in sends the specified aggregation degree to the cluster terminal.

In this embodiment, the network side entity may also issue indication information to the cluster terminal, where the indication information is used to indicate the subframe that needs to receive the cluster downlink multicast channel.

In this embodiment, a device for detecting and processing downlink control information is also provided, which is located in the network side entity and is used to implement the above method. As shown in FIG. 4, the device includes:

The configuration module 40 is connected to the allocation module 42, and is used to configure a dedicated group-specific search space for each group for the cluster downlink multicast channel in the broadband trunking communication system, wherein the group-specific search space is composed of Cluster radio network temporary identifier T-RNTI identifier;

The allocation module 42 is configured to allocate a specified aggregation degree for the physical downlink control channel PDCCH in the configured group-specific search space, wherein the cluster terminal performs blind detection on the PDCCH in the group-specific search space according to the specified aggregation degree.

Example 2

This embodiment is a processing solution corresponding to Embodiment 1, which is mainly described on the terminal side. The method in this embodiment is applied to a cluster terminal. Specifically, FIG. 5 is a flowchart of a method for detecting downlink control information according to Embodiment 2 of the present invention. As shown in FIG. 5 , the method includes:

Step S502, receiving a designated aggregation degree from the network side entity, wherein the designated aggregation degree is that the network side entity allocates for the PDCCH within the configured group-specific search space for the cluster downlink multicast channel in the broadband trunking communication system , and the group-specific search space is identified by the cluster radio network temporary identifier T-RNTI;

Step S504, perform blind detection on the PDCCH in the group-specific search space according to the specified aggregation degree.

Same as in Embodiment 1, in this embodiment, the specified aggregation degree is the aggregation degree assigned by the network side entity to the physical downlink control channel PDCCH masked by the T-RNTI for each T-RNTI, and the specified aggregation degree is related to There is no intersection between the cell wireless network temporary identifier C-RNTI and the PDCCH aggregation degree concealed by the SPS C-RNTI.

In this embodiment, a device for detecting downlink control information is also provided, which is located in the cluster terminal and used to implement the above method. As shown in FIG. 6, the device includes:

The receiving module 60 is connected to the detection module 62, and is used to receive the designated aggregation degree from the network side entity, wherein the designated aggregation degree is the network side entity for the cluster downlink multicast channel in the broadband trunking communication system. In the group-specific search space, the aggregation degree allocated for the physical downlink control channel PDCCH, and the designated aggregation degree is identified by the temporary identifier T-RNTI of the cluster radio network;

The detection module 62 is configured to perform blind detection on the PDCCH in the group-specific search space according to a specified aggregation degree.

In order to better understand the above-mentioned embodiment, the following in conjunction with embodiment 3 and embodiment 4 describe in detail

Example 3

This embodiment provides a method for detecting downlink control information in an LTE-based broadband trunking communication system, which can be used to simultaneously perform UE-specific Detection of downlink control information (such as: uplink authorization) in the search space and downlink control information (such as: downlink cluster scheduling information) in the group-specific search space, so as to meet the requirements of downlink when common services and cluster services coexist in the cluster system Control information detection requirements.

In order to achieve the above object, the technical scheme adopted in this embodiment is as follows:

The cluster system defines a group-specific search space for each cluster group, and the search space is generated based on T-RNTI. Wherein, T-RNTI is a cell unique identifier of this group, which is assigned when the group downlink connection is established, and all listening users in the group use T-RNTI to receive the cluster downlink multicast channel.

The trunking system allocates a fixed PDCCH CCE aggregation degree for the PDCCH masked by T-RNTI. The fixed PDCCE CCE aggregation area can be selected as 4 or 8, and the system broadcasts messages or related information during the group downlink establishment process. command to indicate this value to the cluster terminal.

The trunking system also indicates to the terminal which subframes need to receive the downlink trunking multicast channel through a system broadcast message, or through related signaling during the establishment of the group downlink connection.

For each group, the system adopts the following methods when performing DCI planning allocation for each subframe and determining the PDCCH aggregation degree:

On those subframes that do not require the terminal to receive the cluster downlink multicast channel, the relevant methods of the existing LTE network are still used to process the PDCCH masked by C-RNTI/SPS C-RNTI, and no change is required;

When determining the PDCCH aggregation degree masked by C-RNTI/SPSC-RNTI on those subframes that require the terminal to receive the cluster downlink multicast channel, it is necessary to avoid the aforementioned fixed aggregation used for the PDCCH masked by T-RNTI degree, and choose from the rest of the aggregation degree set.

Correspondingly, the terminal performs PDCCH blind detection in each subframe as follows:

If the cluster group downlink connection has not been established, or on those subframes that do not need to receive the cluster downlink multicast channel, the existing PDCCH blind detection method is still used, including: in the common search space and defined by C-RNTI Search for the PDCCH masked by C-RNTI/SPS C-RNTI in the UE-specific search space;

On those subframes that need to receive the cluster downlink multicast channel, perform T-RNTI masked PDCCH detection in the common search space and the dedicated search space defined based on T-RNTI, and only Use the aforementioned fixed cluster PDCCH CCE aggregation degree to search;

On those subframes that need to receive the cluster downlink multicast channel, perform C-RNTI/SPS C-RNTI masked PDCCH detection in the common search space and UE-specific search space defined based on C-RNTI, and at the same time perform UE-specific search When detecting in space, avoid the aforementioned fixed cluster PDCCH CCE aggregation degree to search.

It can be seen from the above that in this embodiment, for the cluster downlink multicast channel, a new "group-specific search space" is newly added, and the search space is defined by the corresponding group T-RNTI; the group-specific search space In the space, the PDCCH masked by T-RNTI adopts a fixed CCE aggregation degree, such as 4 or 8, and is indicated to the terminal through system messages or signaling; on subframes that require the terminal to receive the cluster downlink multicast channel, In the UE-specific search space defined by the C-RNTI, when the trunking system allocates resources for the PDCCH masked by the C-RNTI/SPS C-RNTI, it needs to avoid the fixed CCE aggregation used by the PDCCH masked by the above T-RNTI degree, and select from the remaining aggregation degree sets; the terminal can perform C-RNTI/SPS C-RNTI addition in the UE-specific space defined by C-RNTI on the subframe that needs to receive the cluster downlink multicast channel Masked PDCCH detection, and at the same time perform T-RNTI masked PDCCH detection in the group-specific search space defined by T-RNTI;

For terminal implementation, since the CCE aggregation degrees of PDCCHs in the two dedicated search spaces do not overlap, the complexity of PDCCH blind detection by the terminal does not actually increase, which is a key point. On the other hand, although the aggregation degree of the original part of the PDCCH is restricted, the impact area is very small (only affects the cluster group users, and only affects those subframes that need to receive the cluster downlink multicast channel) , and the system equipment can use some other means (for example: avoid allocating the CCE aggregation degree on these subframes, it can be postponed to other subframe scheduling, or increase the CCE aggregation degree if the space in the control area is sufficient) to reduce the impact to minimum. Therefore, the application of this method has little impact on the current LTE terminals and system equipment that need to be modified in order to support the cluster.

In this embodiment, two alternatives to the above embodiment are also provided:

The first alternative is to forcibly add a group-specific search space, and at the same time do not make any restrictions on the CCE aggregation degree of the original C-RNTI/SPS C-RNTI masking PDCCH, but this will inevitably mean that the terminal performs PDCCH blinding The rise of the detection complexity is contrary to the original intention of the present invention.

In the second alternative, in the original UE-specific search space, for the part of "DCI format 1or 1B or1D or 2or 2A or 2B", you can designate a PDCCH search dedicated to the cluster-specific search space, so that it can still be achieved. Increase the number of times of Viterbi decoding in the terminal PDCCH blind detection process. However, this undoubtedly puts forward higher requirements on the implementation flexibility of the existing LTE terminal, and it must be considered whether the existing terminal can support it.

Example 4

This embodiment provides a broadband trunking digital communication system based on the existing LTE system. When defining the trunking-related RNTI, a range is specially designated for the T-RNTI, for example, a section of 0001~FFF3 with a length of 4096 scope. Wherein, T-RNTI is a cell unique identifier of each group, which is assigned when the group downlink connection is established, and all listening users in the group use T-RNTI to receive the cluster downlink multicast channel.

In this embodiment, the cluster system defines a group-specific search space for each cluster group, and the search space is generated based on the T-RNTI. For example: we can learn from the way of using the hash function to generate the exclusive search space in the existing LTE specification, the search space of the aggregation degree L (L takes the value in the set {1,2,4,8}) When calculating based on the parameter Y _k , Y _-1 is equal to T-RNTI:

Wherein, the meaning of Y _k is: the starting CCE offset address in the PDCCH search space. The following table k represents the subframe number (0<=k<=9), where the subscript -1 represents the initialization value.

Y _k =(A*Y _k-1 )mod D

Wherein, D means the total number of CCEs included in the PDCCH search space.

Among them, mod is the modulo operation, A=39827, D=6557, and k is the subframe number (0~9). Then, the PDCCH candidate set corresponding to the aggregation degree L is defined as:

L*{(Y _k +m)mod floor(N _CCE,K /L)}+i

Wherein, m is an index of a PDCCH candidate for a certain degree of aggregation L. i represents the index of the CCE in each PDCCH candidate. floor represents the calculation of "round down".

Among them, N _CCE,k represents the number of CCEs contained in the control area in the kth subframe, i=0,...,L–1 represents the sequence number of L CCEs contained in a PDCCH, m=0,..., M ^(L) -1 where M ^(L) is the number of PDCCH candidates with an aggregation degree L defined by the LTE specification.

The trunking system allocates a fixed PDCCH CCE aggregation degree for the PDCCH masked by the T-RNTI. Considering the need to cover the reception of group users located at the edge of the cell, the fixed PDCCE CCE aggregation area can be selected as 4 or 8, and the cluster terminal is indicated to the cluster terminal through a system broadcast message or through related signaling during the group downlink connection establishment process. value.

As shown in Fig. 7, it is assumed that Y _k = 38 in the kth subframe is calculated according to the T-RNTI, and the control area in the kth subframe contains N _{CCEs, and k} = 42 CCEs. At the same time, the system fixes the CCE aggregation degree L=4 of the PDCCH masked by the T-RNTI. Then according to the above calculation, it can be obtained that the CCE start offset addresses of the corresponding M ⁽⁴⁾ = 2 candidate PDCCHs in the control area are respectively equal to:

The start of the PDCCH candidate position corresponding to m=0: 4*{(36+0)mod floor(42/4)}=24

The start of the PDCCH candidate position corresponding to m=1: 4*{(36+1)mod floor(42/4)}=28

On the other hand, the trunking system also indicates to the terminal which subframes need to receive the downlink trunking multicast channel through a system broadcast message or related signaling during the establishment of the group downlink connection. For example, according to the system scheduling period, a bitmap can be defined. Each bit in the bitmap represents whether the corresponding subframe can carry the cluster downlink multicast channel. The length of the bitmap is the network scheduling period. After receiving the bitmap, the cluster terminal can know which subframes need to receive the cluster downlink multicast channel. However, for those terminals that do not support clustering, or terminals that have not yet established a clustering downlink multicast service, these instructions can be ignored, and ordinary LTE services can still be performed in the original manner.

In the subframes in which the cluster terminal needs to receive the cluster downlink multicast channel, if the system also allocates other PDCCHs masked by C-RNTI or SPS C-RNTI in the same subframe for the cluster terminal in the UE-specific search space, for example Uplink authorization, when determining the CCE aggregation degree of the PDCCH, it is necessary to avoid the above-mentioned fixed CCE aggregation degree allocated for the PDCCH masked by the T-RNTI.

Continuing to refer to FIG. 7 , it is assumed that Y _k =9 in the kth subframe is calculated according to the C-RNTI. At the same time, since the system selects the CCE aggregation degree L=4 of the PDCCH masked by T-RNTI, for the PDCCH masked by C-RNTI or SPS C-RNTI, the selected CCE aggregation degree needs to avoid L=4, that is, L Only {1,2,8} can be selected. Then, according to the calculation according to the original formula of the LTE specification, the CCE start offset address of the corresponding candidate PDCCH in the control area can be obtained as follows:

L=1 (a total of M ⁽¹⁾ =6 PDCCH candidates are included):

The start of the PDCCH candidate position corresponding to m=0: 1*{(9+0)mod floor(42/1)}=9

The start of the PDCCH candidate position corresponding to m=1: 1*{(9+1)mod floor(42/1)}=10

The start of the PDCCH candidate position corresponding to m=2: 1*{(9+2)mod floor(42/1)}=11

The start of the PDCCH candidate position corresponding to m=3: 1*{(9+3)mod floor(42/1)}=12

The start of the PDCCH candidate position corresponding to m=4: 1*{(9+4)mod floor(42/1)}=13

The start of the PDCCH candidate position corresponding to m=5: 1*{(9+5)mod floor(42/1)}=14

L=2 (contains a total of M ⁽²⁾ =6 PDCCH candidates):

The start of the PDCCH candidate position corresponding to m=0: 2*{(9+0)mod floor(42/2)}=18

The start of the PDCCH candidate position corresponding to m=1: 2*{(9+1)mod floor(42/2)}=20

The start of the PDCCH candidate position corresponding to m=2: 2*{(9+2)mod floor(42/2)}=22

The start of the PDCCH candidate position corresponding to m=3: 2*{(9+3)mod floor(42/2)}=24

The start of the PDCCH candidate position corresponding to m=4: 2*{(9+4)mod floor(42/2)}=26

The start of the PDCCH candidate position corresponding to m=5: 2*{(9+5)mod floor(42/2)}=28

L=8 (contains a total of M ⁽⁸⁾ =2 PDCCH candidates):

The start of the PDCCH candidate position corresponding to m=0: 8*{(9+0)mod floor(42/8)}=32

The start of the PDCCH candidate position corresponding to m=1: 8*{(9+1)mod floor(42/8)}=0

It should be noted that, for non-cluster terminals, or for those subframes where the cluster terminals do not need to receive the cluster downlink multicast channel, the system can still press {1,2,4, 8) In the set, according to the existing criteria, select the C-RNTI or SPS C-RNTI masked PDCCHCCE aggregation degree. Therefore, the above method has no impact on the original PDCCH process associated with the LTE common service.

On the other hand, even in the subframes where the cluster terminal needs to receive the cluster downlink multicast channel, in the corresponding UE-specific search space, the system still has some means to solve the above-mentioned restriction that a CCE aggregation degree cannot be selected. . For example, assume that the CCE aggregation degree of 4 has been reserved for the PDCCH masked by the T-RNTI, but the system finds that it is more appropriate to select the CCE aggregation degree equal to 4 for the terminal's PDCCH according to the estimation of the terminal's downlink PDCCH reception quality, so that There may be a conflict, and there are two ways to deal with it at this time:

Method A: If the remaining space in the control area is sufficient, select the aggregation degree equal to 8 for the C-RNTI or SPSC-RNTI masked PDCCH in the subframe;

Method B: If the terminal’s uplink business throughput rate is not high, such as voice or medium and low-speed uplink data transmission, then you can choose to perform C-RNTI or For PDCCH scheduling covered by SPS C-RNTI, the choice of CCE aggregation degree is no longer restricted.

It can be seen from the above embodiments that the method provided by the present invention can support the definition of the group-specific search space, and at the same time, the impact on the original DCI planning and scheduling of the system equipment and the selection of the PDCCH CCE aggregation degree is relatively small, and there is It is beneficial to quickly transform the existing LTE system equipment to support the trunking communication function.

Implementation on the terminal side:

Corresponding to the implementation manner on the system side, the terminal performs PDCCH blind detection in each subframe as follows.

Specifically, the terminal learns the fixed CCE aggregation value allocated by the system for the T-RNTI masked PDCCH, such as 4 or 8, by reading system information or receiving related signaling when the group connection is established. Then, the terminal also needs to read system messages, or receive related signaling when the group connection is established, to obtain information about subframes where the system may schedule the cluster downlink multicast channel, such as a bitmap.

When the cluster group downlink connection has not been established, or on those subframes that do not need to receive the cluster downlink multicast channel, the existing PDCCH blind detection method is still used, including: in the common search space and defined by C-RNTI Search for the PDCCH masked by C-RNTI or SPS C-RNTI in the UE-specific search space.

On those subframes where the terminal needs to receive the cluster downlink multicast channel, perform T-RNTI masked PDCCH detection in the common search space and the dedicated search space defined based on T-RNTI, and at the same time detect in the group-specific search space Only use the aforementioned fixed cluster PDCCH CCE aggregation degree to search.

The above processing process can be specifically expressed as the processing flow shown in Figure 8, as shown in Figure 8, the flow includes:

Step S802, start;

Step S804, judging whether a subframe for cluster scheduling is planned, if so, go to step S806, otherwise, go to step S818;

Step S806, acquiring the CCE aggregation degree T of the cluster group scheduling downlink control information.

Step S808, judging whether the degree of aggregation of the CCE is equal to 8? If yes, go to step S810, otherwise, go to step S814;

Step S810, in the public search space and the group-specific search space defined by the T-RNTI, perform the blind detection of the PDCCH masked by the T-RNTI according to the CCE aggregation degree of 8.

Step S812, in the public search space and the UE-specific search space defined by the C-RNTI, respectively perform C-RNTI/SPS C-RNTI masked PDCCH blind detection according to CCE aggregation degrees 1, 2, and 4. Go to step S820;

Step S814, in the public search space and the group-specific search space defined by the T-RNTI, perform the blind detection of the PDCCH masked by the T-RNTI according to the CCE aggregation degree 4. Go to step S816;

Step S816, in the public search space and the UE-specific search space defined by the C-RNTI, perform C-RNTI/SPS C-RNTI masked PDCCH blind detection according to CCE aggregation degrees 1, 2, and 8 respectively. Go to step S820;

Step S818, in the public search space and the UE-specific search space defined by the C-RNTI, respectively perform C-RNTI/SPS C-RNTI masked PDCCH blind detection according to CCE aggregation degrees 1, 2, 4, and 8.

Step S820, end.

In this embodiment, the aggregation degree selected by the T-RNTI masked PDCCH is not limited to 8 and can be other values. For example, referring to FIG. 7, it is assumed that the terminal knows that the system selects CCE aggregation for the T-RNTI masked PDCCH degree is fixed to 4, then the detection of PDCCH masked by T-RNTI is performed in the group-specific search space calculated based on T-RNTI and corresponding to L=4. As shown in the figure, only two PDCCH candidate detections need to be done That's it. At the same time, the terminal will also detect the PDCCH masked by the T-RNTI in the common search space.

On those subframes where the terminal needs to receive the cluster downlink multicast channel, perform C-RNTI/SPS C-RNTI masked PDCCH detection in the public search space and the UE-specific search space defined based on C-RNTI, and at the same time When detecting in the search space, the aforementioned fixed cluster PDCCH CCE aggregation degree is avoided for searching.

For example, referring to Figure 7, assuming that the terminal knows that the system selects a fixed CCE aggregation degree of 4 for the PDCCH masked by the T-RNTI, then the UE-specific search The detection of PDCCH masked by C-RNTI or SPS C-RNTI in the space. This means that corresponding to the CCE aggregation degrees of L=1, 2, and 8 respectively, it is necessary to perform detection of 6, 6, and 2 PDCCH candidates in sequence. At the same time, the terminal will also detect the PDCCH masked by the C-RNTI or SPSC-RNTI in the public search space.

Therefore, referring to Figure 7, when the terminal searches in the common search space, UE-specific search space and group-specific search space: on the one hand, the PDCCH detection mechanism in the common search space remains unchanged from the original implementation of the LTE terminal; on the other hand On the one hand, since the PDCCH CCE aggregation degrees in the UE-specific search space and the group-specific search space have no intersection, that is, overall, the search is still performed according to the CCE aggregation degrees equal to 1, 2, 4, and 8. Therefore, the overall PDCCH detection complexity does not increase compared with the original implementation of the LTE terminal, that is, a total of 44 Viterbi decodings need to be performed in each subframe.

It can be seen from the above embodiments that by adopting the embodiments of the present invention, the terminal can simultaneously support PDCCH detection in the UE-specific search space and the group-specific search space in the same subframe, and will not increase the PDCCH blind detection of existing LTE terminals. Complexity, which is conducive to the rapid transformation of existing LTE terminals to support trunking communication functions.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (7)

1. a check processing method for Downlink Control Information, for network side entity, is characterized in that, comprising:

Be that each group configures a special exclusive search volume of group respectively for the cluster downlink multicast channel in broadband cluster communication system, wherein, the exclusive search volume of this group is identified by cluster wireless Network Temporary Identifier T-RNTI;

In the exclusive search volume of described group of configuration, distribute for physical downlink control channel PDCCH and specify the degree of polymerization, make colony terminal carry out blind Detecting according to the described appointment degree of polymerization to the PDCCH in the exclusive search volume of described group;

Distribute for physical downlink control channel PDCCH and specify the degree of polymerization, comprising:

The physical downlink control channel PDCCH covered is added to each described T-RNTI and distributes a described appointment degree of polymerization, wherein, the described appointment degree of polymerization and Cell Radio Network Temporary Identifier/Identity, Cell-RNTI C-RNTI and semi-continuous distribution cell-radio network identify SPS C-RNTI and add the PDCCH degree of polymerization covered without common factor;

Add after the physical downlink control channel PDCCH covered distributes a described appointment degree of polymerization to each described T-RNTI, also comprise:

Described colony terminal is being needed to receive in the subframe of cluster downlink multicast channel, the PDCCH degree of polymerization selecting C-RNTI and SPS C-RNTI to add from the degree of polymerization outside the described appointment degree of polymerization to cover.

2. method according to claim 1, is characterized in that, the exclusive search volume of described group configures in the following manner:

In the exclusive search volume of UE, divide specified search range as the exclusive search volume of described group.

3. method according to claim 1 and 2, is characterized in that, adds the physical downlink control channel PDCCH covered and distributes one and specify after the degree of polymerization, also comprise each described T-RNTI to T-RNTI:

The described appointment degree of polymerization is issued to colony terminal by the appointment signaling in system broadcast message or cluster downlink connection establishment process.

4. method according to claim 1 and 2, is characterized in that, also comprises:

Issue indication information to described colony terminal, wherein, this indication information is used to indicate the subframe needing to receive cluster downlink multicast channel.

5. a detection method for Downlink Control Information, for colony terminal, is characterized in that, comprising:

Receive the appointment degree of polymerization coming from network side entity, wherein, this appointment degree of polymerization is that network side entity is for the cluster downlink multicast channel in broadband cluster communication system, in the exclusive search volume of group of configuration, for the appointment degree of polymerization that physical downlink control channel PDCCH is distributed, further, the exclusive search volume of described group is identified by cluster wireless Network Temporary Identifier T-RNTI;

According to the described appointment degree of polymerization, blind Detecting is carried out to the PDCCH in the exclusive search volume of described group;

Wherein, to be described network side entity add to each described T-RNTI the degree of polymerization that the physical downlink control channel PDCCH covered distributes to the described appointment degree of polymerization, and the described appointment degree of polymerization and Cell Radio Network Temporary Identifier/Identity, Cell-RNTI C-RNTI and SPS C-RNTI add the PDCCH degree of polymerization covered without common factor;

After network side entity distributes the described appointment degree of polymerization, described colony terminal is being needed to receive in the subframe of cluster downlink multicast channel, the PDCCH degree of polymerization selecting C-RNTI and SPSC-RNTI to add from the degree of polymerization outside the described appointment degree of polymerization to cover.

6. a check processing device for Downlink Control Information, is arranged in network side entity, it is characterized in that, comprising:

Configuration module, for for the cluster downlink multicast channel in broadband cluster communication system, for each group configures a special exclusive search volume of group respectively, wherein, the exclusive search volume of this group is identified by cluster wireless Network Temporary Identifier T-RNTI;

Distribution module, in the exclusive search volume of described group of configuration, distribute for physical downlink control channel PDCCH and specify the degree of polymerization, wherein, colony terminal carries out blind Detecting according to the described appointment degree of polymerization to the PDCCH in the exclusive search volume of described group;

Described distribution module, a described appointment degree of polymerization is distributed specifically for adding the physical downlink control channel PDCCH covered to each described T-RNTI, wherein, the described appointment degree of polymerization and Cell Radio Network Temporary Identifier/Identity, Cell-RNTI C-RNTI and semi-continuous distribution cell-radio network identify SPS C-RNTI and add the PDCCH degree of polymerization covered without common factor;

Described distribution module, also specifically for adding after the physical downlink control channel PDCCH covered distributes a described appointment degree of polymerization to each described T-RNTI, described colony terminal is being needed to receive in the subframe of cluster downlink multicast channel, the PDCCH degree of polymerization selecting C-RNTI and SPSC-RNTI to add from the degree of polymerization outside the described appointment degree of polymerization to cover.

7. a checkout gear for Downlink Control Information, is arranged in colony terminal, it is characterized in that, comprising:

Receiver module, for receiving the appointment degree of polymerization coming from network side entity, wherein, this appointment degree of polymerization is that network side entity is for the cluster downlink multicast channel in broadband cluster communication system, in the exclusive search volume of group of configuration, for the degree of polymerization that physical downlink control channel PDCCH is distributed, and the exclusive search volume of described group is identified by cluster wireless Network Temporary Identifier T-RNTI;

Detection module, for carrying out blind Detecting according to the described appointment degree of polymerization to the PDCCH in the exclusive search volume of described group;

Wherein, to be described network side entity add to each described T-RNTI the degree of polymerization that the physical downlink control channel PDCCH covered distributes to the described appointment degree of polymerization, and the described appointment degree of polymerization and Cell Radio Network Temporary Identifier/Identity, Cell-RNTI C-RNTI and SPS C-RNTI add the PDCCH degree of polymerization covered without common factor;

After network side entity distributes the described appointment degree of polymerization, described colony terminal is being needed to receive in the subframe of cluster downlink multicast channel, the PDCCH degree of polymerization selecting C-RNTI and SPSC-RNTI to add from the degree of polymerization outside the described appointment degree of polymerization to cover.