Background
LTE (Long Term Evolution ) is the Evolution of 3G (3rd Generation, third Generation digital communication), LTE improves and enhances the 3G over-the-air access technology, and adopts OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multiple Input Multiple Output) as the LTE wireless network Evolution standard. In the LTE system and the previous wireless communication system, there is only one carrier in one cell, as shown in fig. 1, the maximum bandwidth in the LTE system is 20 MHz; under the spectrum bandwidth of 20MHz, LTE can provide the peak rate of 100Mbit/s downlink and 50Mbit/s uplink, improve the performance of cell edge users, improve the cell capacity and reduce the system delay. In addition, in the LTE system, a UE (User Equipment) can only operate on one carrier at the same time, and one LTE cell has only one carrier, and each LTE cell is identified by a number unique in the network.
As the number of mobile end users increases rapidly, the traffic capacity of the end users increases exponentially, and in order to meet the ever-increasing traffic demands of the end users, it is necessary to provide more bandwidth to meet the higher peak rates required by the end users' traffic and applications. In an LTE-a (LTE-Advanced ) system, the peak rate of the system is greatly improved compared with that of LTE, and it is required to reach 1Gbps downlink and 500Mbps uplink, and at this time, if only one carrier with the maximum bandwidth of 20MHz is used, it is obviously impossible to reach the peak rate. Therefore, the LTE-a system needs to expand the bandwidth that can be used by the end user, thereby introducing a CA (Carrier Aggregation) technology that aggregates multiple continuous or discontinuous carriers under the same eNB (or base station) (which cannot be aggregated between cells or component carriers under different enbs) and simultaneously serves the UE to provide the rate required by the UE. The aggregated carriers are also called CC (Component Carrier), each cell may be a Component Carrier, and cells (Component carriers) under different enbs cannot be aggregated. In addition, in order to ensure that the UE under LTE can operate under each aggregated carrier, each carrier is required to not exceed 20MHz at most when carrier aggregation is performed, as shown in fig. 2, which is a schematic diagram of a carrier aggregation technology under LTE-a, it can be seen that there are 4 carriers that can be aggregated under the base station of LTE-a, and the base station can perform data transmission with the UE on the 4 carriers at the same time, so as to improve system throughput.
In the LTE system, the downlink physical channel includes: PDSCH (Physical Downlink shared Channel), PBCH (Physical Broadcast Channel), PMCH (Physical Multicast Channel), PCFICH (Physical Control Format Indicator Channel), PDCCH (Physical Downlink Control Channel), PHICH (Physical hybrid ARQ Indicator Channel).
In the above downlink physical channels, the PDCCH channel is mainly used to transmit scheduling signaling for uplink and downlink, and the PDSCH channel is mainly used to transmit downlink data, in general, there are both PDCCH and PDSCH channels on one component carrier, and both are divided by time domain, as shown in the PDCCH and PDSCH channel schematic diagram shown in fig. 3.
In the LTE system, since there is only one component carrier, the PDCCH on one CC can only schedule the PDSCH on the CC. For a multi-carrier system, the following may exist: the PDCCH on one CC is contaminated (e.g., the interference on the PDCCH channel is severe), and at this time, a cross-carrier scheduling function may be configured on other DL (downlink) CCs, that is, the PDCCH on one CC may schedule PDSCH on multiple DL CCs. It should be noted that one DLPDSCH CC can only be scheduled by one PDCCHCC at the same time, and the scheduling relationship is based on CC semi-static configuration.
As the scheduling relationship of PDCCH and PDSCH shown in fig. 4, for DL CC whose PDCCH is contaminated or cannot be used, it may be called PDSCH-only CC, and in fig. 4, PDSCH on CC2 cannot be scheduled by PDCCH on CC2, but can be scheduled by PDCCH on CC 1.
In a multi-carrier system, a base station may configure a working carrier set, referred to as a configuration CC set for short, for a UE according to a sum of maximum rates of all services requested by the UE (User Equipment). In a CC set configured for a UE, a multi-carrier system selects one CC as a PCC (primary component carrier) of the UE based on the UE, and configures other CCs in the CC set as SCCs (secondary component carriers) of the UE. It is noted that the PCC may be different for different UEs.
In addition, in the LTE-a system, the PCC of the UE is not allowed to be activated or deactivated, the PCC is always activated by default, and the SCCs in the configured CC set are deactivated by default after configuration, and if the SCCs need to be used, a carrier activation operation needs to be performed on the SCCs first. Because the service of the UE may have volatility and burstiness, that is, the service volume in a certain period of time is small, and the service volume in a certain period of time is large, when the service volume of the UE is small, in order to save power better, it is necessary to further perform carrier activation or deactivation operation on CCs in the configured CC set according to the current service condition of the UE, and for the deactivated carriers, the UE does not need to monitor the PDCCH, so that a better power saving effect can be achieved.
In the prior art, activation/deactivation operations for carriers in a multi-carrier system have been specified, and may be performed explicitly or implicitly. The explicit activation/deactivation is, that is, a carrier activation/deactivation MAC CE (MAC control element, MAC control layer control element) is used, the MAC CE uses a bitmap (bit mapping) manner, each bit corresponds to one CC (as PCC cannot be activated/deactivated, there may be a separately corresponding bit or none for PCC), if a bit is set to 0, it indicates that the corresponding CC is deactivated, and if a bit is set to 1, it indicates that the corresponding CC is activated. Implicit deactivation is to deactivate the corresponding CC by using the deactivation timer, if the deactivation timer times out. It should be noted that, carrier activation/deactivation is for a downlink SCC, and there is no carrier activation/deactivation operation for an uplink CC at present.
In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:
in the carrier deactivation process, there is no description of how PDCCH CC and PDSCH CC interact when the carrier is deactivated in the current protocol. If one PDSCH CC is deactivated without processing the search space of the corresponding PDCCH CC, unnecessary blind detection and unnecessary power consumption are inevitably caused.
Detailed Description
The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In a multi-carrier system, in order to improve a peak rate, a UE may operate on a plurality of component carriers, the multi-carrier system may configure an operating carrier set for the UE according to a sum of average rates of services requested by the UE, and since the services of the UE may have volatility and burstiness, for better power saving when the traffic of the UE is small, carriers in the operating carrier set configured for the UE may be further subjected to a carrier deactivation operation according to a current service condition of the UE. The embodiment of the invention provides a method for interacting PDCCH CC and PDSCH CC when the multi-carrier system carrier is deactivated, and determining the search space of the PDCCH CC according to the activation state of the PDSCH CC.
An embodiment of the present invention provides a method for determining a PDCCH CC search space, as shown in fig. 5, including the following steps:
step 501, the user equipment acquires the activation state of the PDSCH CC.
Step 502, the user equipment determines the search space of the PDCCH CC according to the activation state of the PDSCH CC.
In the embodiment of the present invention, the acquiring, by the user equipment, the activation state of the PDSCH CC specifically includes: and the user equipment receives the carrier activation/deactivation MAC CE from the network side equipment, and acquires the activation state of the PDSCH CC according to the indication information in the MAC CE.
Acquiring the activation state of the PDSCH CC according to the indication information in the MAC CE, wherein the activation state comprises the following steps: and the user equipment acquires the bit corresponding to the PDSCH CC, and when the bit corresponding to the PDSCH CC is a deactivation indication, the user equipment acquires the activation state of the PDSCH CC as deactivation.
In addition, determining a search space of a PDCCH CC according to the activation status of the PDSCH CC includes: and when the activation state of the PDSCH CC is deactivation, the user equipment performs blind detection on the control channel on the PDCCH CC according to the PDCCH CC and a search space corresponding to a transmission mode on the activated PDSCH CC scheduled by the PDCCH CC.
Further, the blind detection of the control channel on the PDCCH CC by the user equipment according to the PDCCH CC and the search space corresponding to the transmission mode on the activated PDSCHCC scheduled by the PDCCH CC includes: when the search spaces of the PDCCH CC and the PDSCH CC are not independent and the control channel on the PDCCH CC is subjected to blind detection, if the scheduling signaling aiming at the deactivated PDSCH CC is detected on the PDCCH CC, the user equipment ignores the scheduling signaling aiming at the PDSCH CC.
In addition, in the embodiment of the present invention, when the MAC CE transmits through the bitmap method, the mapping relationship between the bit and the CC includes: mapping according to the CC number of the cell level; or mapping based on CC numbers of the UE level; or mapping according to the frequency point of the CC; or, signaling is adopted to inform the corresponding relation between the CC and each bit in the carrier deactivation MAC CE.
The user equipment acquiring the activation state of the PDSCH CC as deactivation, and then further comprising: and the user equipment deactivates the CC according to the activation state of the PDSCH CC.
The user equipment deactivates the PDSCH CC according to the activation state of the CC, and specifically includes one or any of the following operations:
the user equipment stops monitoring the PDCCH on the corresponding DL CC;
the user equipment terminates the PDSCH reception on the corresponding DL CC;
if the CC has a deactivated timer running, the user equipment stops the timer;
the user equipment terminates uplink transmission on a UL CC that can only be scheduled by the CC;
the user equipment stops performing downlink CQI feedback aiming at the corresponding DL CC;
if a certain UL CC can only be scheduled by the CC, the user equipment terminates SRS and/or PHR transmission on the UL CC.
Therefore, by using the method provided by the invention, the search space of the PDCCH CC is determined according to the activation state of the PDSCH CC, and the search space can be adjusted in time, so that the aims of reducing the unnecessary PDCCH blind detection times and saving electricity more effectively are fulfilled.
In order to more clearly illustrate the technical solution provided by the embodiment of the present invention, the following describes in detail a method for determining a PDCCH CC search space according to the embodiment of the present invention. In this embodiment of the present invention, a network side device includes, but is not limited to, an eNB (evolved Node B), a Relay, and the like, it should be noted that the network side device is not limited to the above-mentioned device, and all devices located at the network side are within the protection scope of the present invention.
In the embodiment of the present invention, the influence of the activation state of the PDSCH CC on the PDCCH CC is specifically: if one PDSCH CC is deactivated, the impact on the search space needs to be considered when performing blind detection on the PDCCH that can schedule the PDSCH CC.
Specifically, when the activation state of the PDSCH CC is deactivated, the user equipment performs blind detection on the control channel on the PDCCH CC according to the PDCCH CC and a search space corresponding to a transmission mode on the activated PDSCH CC scheduled by the PDCCH CC. Further, when the search spaces of the PDCCH CC and the PDSCH CC are not independent and the control channel on the PDCCH CC is subjected to blind detection, if the scheduling signaling for the deactivated PDSCH CC is detected on the PDCCH CC, the user equipment ignores the scheduling signaling for the PDSCH CC.
Based on the above situation, the method for determining a PDCCH CC search space according to the second embodiment of the present invention, as shown in fig. 6, includes the following steps:
step 601, the network side equipment sends carrier activation/deactivation MAC CE to the UE.
Wherein, in the carrier activation/deactivation MAC CE, a bit corresponding to the PDSCH CC may be included, and the bit is set as a deactivation indication or an activation indication.
Step 602, the ue acquires the activation status of the PDSCH CC according to the carrier activation/deactivation MAC CE.
Specifically, when the bit position corresponding to the PDSCH CC is set as a deactivation indication in the carrier activation/deactivation MAC CE, the activation state of the PDSCH CC is acquired as deactivation; and when the bit position corresponding to the PDSCH CC is set as an activation indication, acquiring the activation state of the PDSCH CC as activation. For example, when the bit position is 0, the deactivation indication is indicated, and when the bit position is 1, the activation indication is indicated, then the user equipment learns that the bit position is 0, and acquires the activation state of the PDSCH CC as deactivation; and when the user equipment learns that the bit is 1, the activation state of the PDSCH CC is acquired as activation.
Certainly, in practical applications, the carrier activation/deactivation MAC CE may not carry a bit corresponding to the PDSCH CC, and at this time, the user equipment may also obtain the activation state of the PDSCHCC in other manners, which is not described in detail in the embodiment of the present invention.
Step 603, when the activation state of the PDSCH CC is deactivated, the user equipment determines the search space of the PDCCH CC according to the activation state of the PDSCHCC. Namely, the user equipment performs blind detection on the PDCCH for scheduling the PDSCH CC according to the search space of the PDCCH CC.
Specifically, when the activation state of the PDSCH CC is deactivated, the user equipment performs blind detection on the control channel on the PDCCH CC according to the PDCCH CC and a search space corresponding to a transmission mode on the activated PDSCH CC scheduled by the PDCCH CC. Further, when the search spaces of the PDCCH CC and the PDSCH CC are not independent and the control channel on the PDCCH CC is subjected to blind detection, if the scheduling signaling for the deactivated PDSCH CC is detected on the PDCCH CC, the user equipment ignores the scheduling signaling for the PDSCH CC.
It should be noted that, when the activation state of the PDSCH CC is deactivation, the ue further needs to perform a deactivation operation on the CC, where the deactivated operation at least includes one or any of the following operations: stopping monitoring the PDCCH on the DL CC; if the CC has a deactivation timer running, stopping the timer; stopping PDSCH transmission (including initial and/or retransmission) on the DL CC; ignoring previous UL scheduling (including initial and/or retransmission) on the DL CC; stopping sending CQI (Channel Quality Indicator) information corresponding to the DL CC on the UL CC; if a certain UL CC can only be scheduled by the DL CC, SRS (Sounding Reference Signal) and/or PHR (power headroom) transmission is stopped on the corresponding UL CC.
In addition, a bitmap mode may be further adopted in the carrier activation/deactivation MAC CE, and when the bitmap mode is adopted, the mapping relationship between bits and CCs may at least adopt any one of the following modes.
(1) Mapping is carried out according to the CC number of the cell level, namely all CCs supported in the cell are numbered uniformly, and each bit of the carrier activation/deactivation MAC CE corresponds to one CC.
(2) And mapping based on CC numbers of the UE level, namely uniformly numbering the CCs which can be aggregated or are already aggregated by the UE, wherein each bit of the carrier activation/deactivation MAC CE corresponds to one CC.
(3) And mapping according to the frequency points of the CCs, namely, each bit of the carrier activation/deactivation MAC CE corresponds to one CC according to the sequence of the CC frequency points from low to high or from high to low.
(4) And adopting signaling to inform the corresponding relation between the CC and each bit in the carrier activation/deactivation MAC CE.
It should be noted that, for the PCC, since the PCC is not activated/deactivated, there may be an independent bit corresponding to the PCC, or there may be no independent bit corresponding to the PCC.
In order to further illustrate the technical solution provided by the embodiment of the present invention, the method for determining the PDCCH CC search space provided by the embodiment of the present invention is described in detail below with reference to a specific application scenario. In this application scenario, it is assumed that the multi-carrier system supports three DL CCs, which are denoted as CC1, CC2, and CC3, where CC1 and CC3 are both PDCCH CCs, CC2 is PDSCH-only CC, the PDCCH of CC2 cannot be used due to interference, CC1 is configured with a cross-carrier scheduling function, and CC3 is not configured with a cross-carrier scheduling function. In addition, it is assumed that the adopted carrier activation/deactivation MAC CE has three reserved bits, and the lowest 5 bits respectively correspond to 5 DL CCs in sequence from the low order to the high order; activation/deactivation a "0" in a MAC CE indicates deactivation and a "1" indicates activation.
Based on the above application scenario, a third embodiment of the present invention provides a method for determining a PDCCH CC search space, where in this embodiment, it is assumed that search spaces of CC1 and CC2 are independent, and as shown in fig. 7, the method includes the following steps:
in step 701, at time T1, the UE normally performs data transmission on DL CC1, CC2, and CC 3.
Step 702, at time T2, when the channel quality of CC1 deteriorates or the data volume of the UE decreases, the network side decides to deactivate CC2, and the base station sends a carrier activation/deactivation MAC CE to the UE. The format of the carrier activation/deactivation MAC CE is shown in fig. 8, where the lowest bit represents CC1, the second last bit represents CC2, and the third last bit represents CC 3.
In step 703, after receiving the carrier activation/deactivation MAC CE, the UE determines that CC2 should be deactivated.
In step 704, when the UE performs blind detection on the PDCCH on CC1, the UE does not need to perform blind detection in the search space corresponding to the CC2 transmission mode.
Specifically, although the CC1 is configured with cross-carrier scheduling, since the CC2 is deactivated, blind detection in a search space corresponding to the transmission mode of the CC2 is not required in a subsequent process of blind detection of the PDCCH on the CC 1.
In the fourth embodiment of the present invention, assuming that search spaces of CC1 and CC2 are not independent, as shown in fig. 9, the method includes the following steps:
in step 901, at time T1, the UE normally performs data transmission on DL CC1, CC2 and CC 3.
Step 902, at time T2, when the channel quality of CC1 deteriorates or the data amount of the UE decreases, and the network side decides to deactivate CC2, the base station may send a carrier activation/deactivation MAC CE to the UE, where the format of the MAC CE is shown in fig. 10, where the lowest bit represents CC1, the second to last bit represents CC2, and the third to last bit represents CC 3.
In step 903, after receiving the carrier activation/deactivation MAC CE, the UE determines that CC2 should be deactivated.
In step 904, when the UE performs blind detection on the PDCCH on CC1, it does not need to perform blind detection in the search space independently corresponding to CC2, and when there is an overlapped part, if the UE detects scheduling for CC2, the UE ignores the scheduling.
Specifically, although cross-carrier scheduling is configured on CC1, since CC2 is deactivated, blind detection in a search space independently corresponding to CC2 is not required when a PDCCH on CC1 is subsequently blind detected, and if there is an overlapping portion, if scheduling for CC2 is detected, the scheduling is ignored, and no processing is performed.
In the fifth embodiment of the present invention, a method for determining a PDCCH CC search space is provided, where a MAC CE is transmitted in a bitmap manner, and it is assumed that a UE aggregates 5 CCs, which are respectively denoted as CC1/CC2/CC3/CC4/CC 5.
According to the serial number of the CC in the cell level, the five CCs are respectively corresponding to 1, 3, 2, 4 and 5; according to the CC number of the UE level, the five CCs respectively correspond to 1, 3, 5, 4 and 2; according to the frequency points, the frequency points are respectively CC1/CC3/CC2/CC4/CC5 from low to high.
Based on the above situation, the bitmap format of the carrier activation/deactivation MAC CE includes: (1) numbering according to the cell level CC, the corresponding relation between each bit and the CC of the carrier activation/deactivation MAC CE is shown in FIG. 11; (2) the correspondence between each bit and CC of the carrier activation/deactivation MAC CE is shown in fig. 12 according to the UE level CC number; (3) numbering according to the frequency from low to high, the corresponding relation between each bit and CC of the carrier activation/deactivation MAC CE is shown in FIG. 13; (4) numbering from high to low according to the frequency, the correspondence between each bit and CC of the carrier activation/deactivation MAC CE is as shown in fig. 14.
Based on the same inventive concept, a user equipment provided in the sixth embodiment of the present invention, as shown in fig. 15, includes:
an obtaining module 11, configured to obtain an activation state of a PDSCH CC;
a determining module 12, configured to determine a search space of a PDCCH CC according to the activation status of the PDSCH CC acquired by the acquiring module 11.
The obtaining module 11 is specifically configured to receive a carrier activation/deactivation MAC CE from a network side device, and obtain an activation state of the PDSCH CC according to indication information in the MAC CE.
The obtaining module 11 is further configured to obtain a bit corresponding to the PDSCH CC, and when the bit corresponding to the PDSCH CC is a deactivation indication, obtain that the activation state of the PDSCH CC is deactivated.
The determining module 12 is specifically configured to, when the activation state of the PDSCH CC is deactivated, perform blind detection on the control channel on the PDCCH CC according to the PDCCH CC and a search space corresponding to a transmission mode on the activated PDSCH CC scheduled by the PDCCH CC.
The determining module 12 is further configured to, when the search spaces of the PDCCH CC and the PDSCH CC are not independent and a control channel on the PDCCH CC is subjected to blind detection, ignore scheduling signaling for the PDSCH CC if scheduling signaling for the deactivated PDSCH CC is detected on the PDCCH CC.
When the MAC CE transmits in a bitmap manner, the mapping relationship between the bits and the CCs includes:
mapping according to the CC number of the cell level; or,
mapping based on CC numbers of the UE level; or,
mapping according to the frequency point of the CC; or,
and adopting signaling to inform the corresponding relation of each bit in the CC and the carrier deactivation MAC CE.
In this embodiment of the present invention, the ue further includes:
a processing module 13, configured to deactivate the PDSCH CC according to the activation state of the CC when the activation state of the CC is deactivation.
The processing module is specifically configured to perform one or any of the following operations:
stopping monitoring the PDCCH on the corresponding DL CC;
terminating PDSCH reception on the corresponding DL CC;
if the CC has a deactivation timer running, stopping the timer;
terminating uplink transmissions on UL CCs that can only be scheduled by the CCs;
terminating downlink CQI feedback for the corresponding DL CC;
if a certain UL CC can only be scheduled by the CC, the SRS and/or PHR transmission on the UL CC is terminated.
The modules of the device can be integrated into a whole or can be separately deployed. The modules can be combined into one module, and can also be further split into a plurality of sub-modules.
Therefore, by using the equipment provided by the invention, the search space of the PDCCH CC is determined according to the activation state of the PDSCH CC, and the search space can be adjusted in time, so that the aims of reducing the number of unnecessary PDCCH blind tests and saving more effectively are fulfilled.
Through the above description of the embodiments, those skilled in the art will clearly understand that the present invention may be implemented by software plus a necessary general hardware platform, and certainly may also be implemented by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute the methods according to the embodiments of the present invention.
Those skilled in the art will appreciate that the drawings are merely schematic representations of one preferred embodiment and that the blocks or flow diagrams in the drawings are not necessarily required to practice the present invention.
Those skilled in the art will appreciate that the modules in the devices in the embodiments may be distributed in the devices in the embodiments according to the description of the embodiments, and may be correspondingly changed in one or more devices different from the embodiments. The modules of the above embodiments may be combined into one module, or further split into multiple sub-modules.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
The above disclosure is only for a few specific embodiments of the present invention, but the present invention is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.