JP6253954B2 - Method for selecting CSI process for cooperative multipoint user and base station - Google Patents

Description

  The present invention relates to the field of wireless communication, and in particular, to a method for selecting a channel state information (CSI) process for a coordinated multi-point (CoMP) user and a base station. .

  The channel state information process (CSI process) is obtained by performing measurement and processing on a signal measurement resource (SMR: Signal Measurement Resource) and an interference measurement resource (Interference Measurement Resource). The CSI process includes parameters such as a rank indicator (RI), a precoding matrix indicator (PMI), and a channel quality indicator (CQI). The CSI process is similar to the CSI process in standards such as 3GPP Rel-8, 3GPP Rel-10.

  For example, coordinated scheduling / dynamic point blanking (CS / DPB: Coordinated Scheduling / Dynamic Point Blanking), dynamic point selection / dynamic point blanking (DPS / DPB: Dynamic Point Selection / Dynamic Point Blanking), and joint transmission (TJ) In order to support various cooperative multipoint (CoMP) transmission schemes such as), the base station needs to receive feedback of various types of CSI processes from the user equipment (UE) to perform joint scheduling. Or the base station updates the received CSI process. Then, joint scheduling is performed by obtaining a new CSI process.

When the CoMP measurement set includes two transmission points (TP: Transmission Point), each of which is TP1 and TP2, when transmission is performed using the DPS method (referred to as 2-TP DPS / DPB), In this case, the base station needs to receive four types of CSI processes, or can obtain four types of CSI processes by updating. As shown in Table 1, these four types of CSI processes (that is, CSI processes corresponding to 2-TP CoMP) include CSI1, CSI2, CSI3, and CSI4. Here, the signal part of CSI1 is from TP1, the interference part is from a transmission point other than TP1 (including TP2 and other transmission points), the signal part of CSI2 is from TP1, and the interference part is other than TP1 and TP2. From the transmission point (that is, other transmission points other than TP1 and TP2 in the wireless communication system), the signal portion of CSI3 is from TP2, and the interference portion is from a transmission point other than TP2 (including TP1 and other transmission points). The signal portion of CSI4 is from TP2, and the interference portion is from a transmission point other than TP1 and TP2. The CSI process corresponding to TP1 is {CSI1, CSI2}, and the CSI process corresponding to TP2 is {CSI3, CSI4}.

If the CoMP measurement set includes three transmission points, each of which is TP1, TP2, and TP3, when transmission is performed using the DPS method (referred to as 3-TP DPS / DPB), in this case, The station needs to receive 12 different CSI processes to obtain joint scheduling, or it needs to obtain 12 different CSI processes by updating. The twelve types of CSI processes (that is, CSI processes corresponding to 3-TP CoMP) are similar in meaning to Table 1 as shown in Table 2 and will not be described here. Here, the CSI process corresponding to TP1 is {CSI1, CSI2, CSI6, CSI10}, the CSI process corresponding to TP2 is {CSI3, CSI4, CSI8, CSI11}, and the CSI process corresponding to TP3 is {CSI5 , CSI7, CSI9, CSI12}.

  However, in the actual system, considering the complexity of the UE and the complexity of the network, particularly the complexity of the UE, the following has been submitted in a standard such as 3GPP Rel-11. That is, the number Nconf of CSI processes (hereinafter referred to as “CSI processes set by the base station”) for the measurement and feedback set by the base station for the UE is determined by the UE capability, May be 1, 3 or 4. Then, when the base station sets Nconf CSI processes for performing measurement and feedback to the UE, all the selectable CSI processes (for example, four types shown in Table 1 for 2-TP situations). The selection of Nconf appropriate CSI processes from the 12 types shown in Table 2) is a problem to be solved.

  The base station can set Nconf (Nconf = 3) CSI processes for performing measurement and feedback to the UE. For example, in the traditional method, 3-TP CoMP shown in Table 2 can be used. As one of the methods, the CSI process is set based on CSI feedback of Rel-8, that is, the CSI processes set by the base station are CSI1, CSI3, and CSI5. Alternatively, select a CSI process with the same interference at three base stations (ie, interference other than the CoMP measurement set), in which case the CSI processes configured by the base stations are CSI10, CSI11, CSI12 It is. To illustrate, these traditional methods are not robust enough to provide better system performance in a variety of wireless communication environments.

  The present invention provides a method and a base station for selecting a channel state information process for cooperative multipoint users.

  A method for selecting a channel state information (CSI) process for a coordinated multipoint (CoMP) user in a wireless communication system, wherein A1 acquires a traffic load of the wireless communication system, and the traffic load is preset. B1 determining the load level of the wireless communication system by comparing with one or more load thresholds and determining different CSI processes set by the base station for different load levels. .

  The B1 compares the traffic load with a preset first load threshold value, and determines that the load level of the wireless communication system is low when the traffic load is smaller than the first load threshold value. Selecting the back CSI as one of the CSI processes set by the base station, and selecting the rest of the CSI processes set by the base station from the CSI processes corresponding to the serving base station, Is greater than the first load threshold, it is determined that the load level of the wireless communication system is high, fallback CSI is excluded from the CSI process set by the base station, and each base station included in the CoMP measurement set is CSI process configured by the base station at least one of the CSI processes corresponding to To be selected, including that.

  The B1 compares the traffic load with a preset first load threshold, and determines that the load level of the wireless communication system is high if the traffic load is greater than the first load threshold, Exclude the back CSI from the CSI process set by the base station, and select at least one CSI process set by the base station from the CSI processes corresponding to each base station included in the first CoMP measurement set. , If the traffic load is less than the first load threshold, determine that the load level of the wireless communication system is low, and select fallback CSI as one of the CSI processes set by the base station; A second CoMP measurement set having a smaller number of base stations than the first CoMP measurement set is newly generated. Includes the CSI process corresponding to a base station included in the second CoMP measurement set, to select the remaining of the CSI process set by the base station, the.

  The B1 compares the traffic load with a preset first load threshold and a second load threshold, respectively, and when the traffic load is smaller than the first load threshold, the load level of the wireless communication system The fallback CSI is selected as one of the CSI processes set by the base station, and from the CSI process corresponding to the serving base station, the rest of the CSI processes set by the base station If the traffic load is greater than the second load threshold, it is determined that the load level of the wireless communication system is high, the fallback CSI is excluded from the CSI process set by the base station, and the CoMP measurement At least one from the CSI process corresponding to each base station included in the set by the base station If the traffic load is greater than the first load threshold and less than the second load threshold, the load level of the wireless communication system is determined to be medium and fallback Select CSI as one of the CSI processes configured by the base station, and at least one of the CSI processes configured by the base station from the CSI process corresponding to each coordinated base station included in the CoMP measurement set. The first load threshold is less than the second load threshold.

  Selecting the CSI process set by the base station from the CSI process corresponding to the base station determines the signal-to-interference noise ratio of each CSI process corresponding to the base station, and in descending order of the signal-to-interference noise ratio. , Selecting a predetermined number of CSI processes set by the base station.

  The traffic load includes resource usage and / or number of users.

  A method for selecting a channel state information (CSI) process for a coordinated multipoint (CoMP) user in a wireless communication system, wherein the parameter difference between a serving cell signal parameter and a coordinated cell signal parameter is determined. And comparing the parameter difference with one or more preset difference thresholds to determine the location of the CoMP user, and for different user locations, different CSI processes set by the base station B2 to be determined.

  The B2 compares the parameter difference with a preset first difference threshold, and if the parameter difference is greater than the first difference threshold, the location of the CoMP user is in the first edge region of the serving cell. Decide to locate and select the fallback CSI as one of the CSI processes set by the base station, and from the CSI process corresponding to the serving base station, the rest of the CSI processes set by the base station And if the parameter difference is less than the first difference threshold, determine that the location of the CoMP user is located in the second edge region of the serving cell and exclude fallback CSI from the CSI process set by the base station From the CSI process corresponding to each base station included in the CoMP measurement set Selecting at least one as a CSI process set by the base station, said method comprising, wherein said first edge region, close to the center of the serving cell than the second edge region.

  The B2 compares the parameter difference with a preset first difference threshold, and if the parameter difference is smaller than the first difference threshold, the position of the CoMP user is in the second edge region of the serving cell. And at least one of the CSI processes corresponding to each base station included in the first CoMP measurement set is configured by the base station, with the fallback CSI being excluded from the CSI process configured by the base station. If the parameter difference is greater than the first difference threshold, it is determined that the location of the CoMP user is located in the first edge region of the serving cell, and the fallback CSI is set by the base station Select one of the CSI processes so that the number of base stations is the first CoMP measurement. Generating a second CoMP measurement set that is less than the set, and selecting the remaining CSI processes set by the base station from the CSI processes corresponding to the base stations included in the second CoMP measurement set; Where the first edge region is closer to the center of the serving cell than the second edge region.

  The B2 compares the parameter difference with a preset first difference threshold and a second difference threshold, respectively, and when the parameter difference is larger than the first difference threshold, the location of the CoMP user is a serving cell. To select the fallback CSI as one of the CSI processes set by the base station and set by the base station from the CSI process corresponding to the serving base station If the remainder of the CSI process is selected and the parameter difference is less than the second difference threshold, it is determined that the location of the CoMP user is located in the second edge region of the serving cell, and the fallback CSI is determined by the base station Corresponding to each base station included in the CoMP measurement set by excluding it from the set CSI process If at least one of the CSI processes is selected as a CSI process configured by a base station and the parameter difference is smaller than the first difference threshold and greater than the second difference threshold, the CoMP user's Determines that the location is located in the third edge region of the serving cell, selects fallback CSI as one of the CSI processes set by the base station, and corresponds to each coordinated base station included in the CoMP measurement set Selecting at least one from the CSI process as the rest of the CSI processes set by the base station, wherein the first difference threshold is greater than the second difference threshold, The edge region of 1 is closer to the center of the serving cell than the second edge region, and the third edge region is Di region is located between the first edge region and the second edge region.

  Selecting the CSI process set by the base station from the CSI process corresponding to the base station determines the signal-to-interference noise ratio of each CSI process corresponding to the base station, and in descending order of the signal-to-interference noise ratio. , Selecting a predetermined number of CSI processes set by the base station.

  The signal parameter includes reference signal reception power, reference signal reception quality, or signal-to-interference noise ratio.

  A method of selecting a channel state information (CSI) process for cooperative multipoint (CoMP) users in a wireless communication system, wherein Nconf user scheduling states or base station transmissions having the highest appearance frequency within a predetermined time zone Determining a state, searching for a CSI process corresponding to the Nconf user scheduling state or base station transmission state from a preliminary set of CSI processes, and setting it as a CSI process configured by a base station, wherein , Nconf is the number of CSI processes set by the base station.

  A base station that selects a channel state information (CSI) process for a cooperative multipoint (CoMP) user, the first means for acquiring a traffic load of a wireless communication system, and the traffic load set in advance A second means for comparing one or more load thresholds to determine a load level of the wireless communication system and for determining different CSI processes set by the base station for different load levels; Is provided.

  The second means compares the traffic load with a preset first load threshold, and determines that the load level of the wireless communication system is low when the traffic load is smaller than the first load threshold. Selecting the fallback CSI as one of the CSI processes set by the base station, and selecting the rest of the CSI processes set by the base station from the CSI processes corresponding to the serving base station; If the traffic load is greater than the first load threshold, it is determined that the load level of the wireless communication system is high and fallback CSI is excluded from the CSI process set by the base station and included in the CoMP measurement set At least one CSI process configured by the base station from the CSI process corresponding to each base station. Selected as Seth.

  A base station that selects a channel state information (CSI) process for a cooperative multipoint (CoMP) user, the first means for determining a parameter difference between a serving cell signal parameter and a cooperative cell signal parameter And comparing the parameter difference with one or more preset difference thresholds to determine the location of the CoMP user, and for different user locations, different CSI processes set by the base station Second means for determining.

  The second means compares the parameter difference with a preset first difference threshold, and if the parameter difference is greater than the first difference threshold, the location of the CoMP user is the first of the serving cell. The CSI process set by the base station from the CSI process corresponding to the serving base station, selecting the fallback CSI as one of the CSI processes set by the base station, If the parameter difference is smaller than the first difference threshold, it is determined that the position of the CoMP user is located in the second edge region of the serving cell, and the fallback CSI is set to the CSI set by the base station. The CSI process corresponding to each base station included in the CoMP measurement set is excluded from the process. From selects at least one as a CSI process set by the base station, wherein the first edge region, close to the center of the serving cell than the second edge region.

  A base station that selects a channel state information (CSI) process for cooperative multipoint (CoMP) users, and determines Nconf user scheduling states or base station transmission states with the highest appearance frequency within a predetermined time period. And a second means for searching for a CSI process corresponding to the Nconf user scheduling state or base station transmission state from a spare set of CSI processes and setting it as a CSI process set by the base station; , Where Nconf is the number of CSI processes set by the base station.

  The method of selecting a CSI process submitted by one or more embodiments in the present invention is based on the network traffic load, eg, resource usage, number of users, etc. Select the CSI process set by. As can be seen, the selection methods provided in the embodiments of the present invention can be adapted to various wireless communication systems and provide better system performance regardless of whether the traffic load in the network environment is high or low. It can also be provided and it can effectively reduce the complexity of network scheduling when the traffic load is low.

  Also, in the embodiments of the present invention, based on the scheduling and / or transmission state within a certain period in the past, or the difference of signal parameters such as RSRP / RSRQ / SINR from the serving cell and the cooperative cell (or the location of the UE). The CSI process set by the base station can be selected.

4 is an implementation flowchart of a method for selecting a CSI process set by a base station in an embodiment of the present invention; FIG. 4 is a schematic diagram of a method for determining a CSI process set by a base station based on a first load threshold in a specific embodiment of the present invention. FIG. 6 is a schematic diagram of a method for determining a CSI process set by a base station based on a first load threshold in another specific embodiment of the present invention. FIG. 6 is a schematic diagram of a method for determining a CSI process set by a base station based on a first load threshold and a second load threshold in yet another specific embodiment of the present invention. 4 is an implementation flowchart of a method for selecting a CSI process set by a base station in another embodiment of the present invention; It is a block diagram of the structure of the base station in the Example of this invention.

  In order to further clarify the object, solution, and merit of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings.

  FIG. 1 is an implementation flowchart of a method for selecting a CSI process set by a base station in an embodiment of the present invention.

  In step 101, the traffic load of the wireless communication system is acquired. Specifically, the traffic load can be determined based on the resource usage rate or the number of users.

  In step 102, the traffic load is compared with one or more preset load thresholds to determine the load level of the wireless communication system and set by different base stations for different load levels. CSI process to be determined. As can be seen, if the wireless communication system has different load levels, the policies for selecting the CSI process set by the base station are not the same.

  Specifically, as one of the differences when selecting the CSI process set by the base station for the two states of low load level and high load level, Fallback for CoMP users Whether to set CSI. Here, the fallback CSI is CSI for single cell transmission such as CSI1 in Table 1 or Table 2, for example.

  When the load level is low, the interference in the network is also small. In this case, the performance of single cell transmission is already sufficient, and the probability that a CoMP user is scheduled for single cell transmission is much greater than the probability of performing CoMP transmission. Therefore, fallback CSI is very important when the traffic load is relatively low and needs to be set for CoMP users. When the load level is high, the network interference is very large and the performance gain due to CoMP transmission is also very large. Therefore, the probability that a CoMP user is scheduled for CoMP transmission is large, much higher than the probability of single cell transmission. In this case, for the CoMP user, the CoMP CSI becomes more important than the fallback CSI. Therefore, fallback CSI is excluded from the CSI process set by the base station.

  When the load level is low, the CSI process set by the base station is selected from the CSI process corresponding to the CS scheme, i.e. from the CSI process with various interference assumptions from the serving cell. For example, when TP1 is a serving base station, the CSI process corresponding to TP1 is a CSI process corresponding to the CS scheme. When the load level is high, the CSI process set by the base station is selected from the CSI processes corresponding to the DPS scheme, and thus can be selected from all CSI processes other than the fallback CSI. In other words, when the load level is high, all CSI processes other than the fallback CSI are all selectable CSI processes.

  As can be seen, step 102 reduced the selection range of the CSI process or decided to select the CoMP scheme. When the load level is low, the performance advantage of the DPS method is not particularly clear compared to the CS method, but the scheduling complexity is significantly larger than that of the CS method. Therefore, when the load level is low, selecting the CSI process set by the base station from the CSI process corresponding to the CS scheme can guarantee the system performance and reduce the complexity of measurement and scheduling. it can. In comparison, when the load level is high, the performance gain of the DPS scheme is significantly greater than that of the CS scheme, so in this case, selecting the DPS scheme can result in higher system performance.

  In a specific embodiment of the present invention, a first load threshold is set in advance and the traffic load of the wireless communication system is acquired, and then the traffic load is compared with the first load threshold. As should be explained, the value of the first load threshold can be set by an experience value or the like.

  If the traffic load is smaller than the first load threshold, it is determined that the load level of the wireless communication system is low, and policy 1 is adopted to select the CSI process set by the base station. Policy 1 specifically selects fallback CSI as the CSI process set by the base station and selects the remaining CSI processes set by the base station from the CSI processes corresponding to the serving base station. That is. For example, when the number of CSI processes set by the base station is Nconf, in addition to the fallback CSI and from the CSI process corresponding to the serving base station, Nconf-1 CSI processes set by the base station Must be selected. If the traffic load is greater than the first load threshold, it is determined that the load level of the wireless communication system is high, and policy 2 is adopted to select the CSI process set by the base station. Policy 2 specifically excludes fallback CSI from the CSI process set by the base station and sets at least one from the CSI process corresponding to each base station included in the CoMP measurement set by the base station. The CSI process is selected. For example, assuming that the CoMP measurement set includes TP1 and TP2, from the CSI process corresponding to TP1, at least one is selected as the CSI process configured by the base station, and the CSI process corresponding to TP2 is selected. Also select at least one as the CSI process set by the base station. This ensures that the selected corresponding CSI process exists at any of the base stations included in the CoMP measurement set. When the traffic load is equal to the first load threshold value, one of the two policies may be adopted to select the CSI process set by the base station, which is not particularly limited. .

  In this specific example, the load level height is evaluated using the first load threshold. Of course, other methods may be adopted to determine the height of the load level.

  Taking 3-TP as an example and assuming that the number of CSI processes Nconf set by the base station is Nconf = 3, as shown in FIG. 2, the traffic load is relatively low (ie, the load level is low). In some cases, fallback CSI (see the area filled with vertical lines in FIG. 2) needs to be selected as the CSI process set by the base station and provided to the CoMP user, and the remaining two, The CSI process set up by the base station is also selected from the CSI of the serving cell, where the CSI of the serving cell may be a CSI process whose signal portion is from the serving base station. For example, when TP1 is a serving base station, CSI1, CSI2, CSI6, and CSI10 in Table 2 are all CSI spare sets of the serving base station, that is, a CSI process corresponding to the serving base station.

  When the traffic load is relatively high (ie, the load level is in the high region), all CSI processes set by the base station are all CoMP CSI. Specifically, at least one may be selected as a CSI process set by the base station from the CSI spare set of each base station included in the CoMP measurement set. For example, if TP1 is a serving base station, TP2 is a first coordinated base station, and TP3 is a second coordinated base station, the CSI reserve set {CSI1, CSI2, CSI6, CSI10} of TP1 (ie, From the spare set 1), select one as the CSI process configured by the base station, and from the CSI spare set {CSI3, CSI4, CSI8, CSI11} of TP2 (ie, spare set 2), one by the base station The CSI process to be set is selected, and one is selected as the CSI process to be set by the base station from the CSI spare set {CSI5, CSI7, CSI9, CSI12} of TP3 (ie, the spare set 3).

  In another specific embodiment of the present invention, the first load threshold value is preset, and the traffic load of the wireless communication system is acquired, and then the traffic load is compared with the first load threshold value. If the traffic load is greater than the first load threshold, it is determined that the load level of the wireless communication system is high, the fallback CSI is excluded from the CSI process set by the base station, and the first CoMP measurement set At least one is selected as a CSI process set by the base station from CSI processes corresponding to each base station included in. If the traffic load is less than the first load threshold, determine that the load level of the wireless communication system is low, select a fallback CSI as one of the CSI processes set by the base station, and A second CoMP measurement set having a smaller number of stations than the first CoMP measurement set is newly generated, and a CSI set by the base station is obtained from a CSI process corresponding to the base station included in the second CoMP measurement set. Select the rest of the process. If the traffic load is equal to the first load threshold, either of the above two policies can be adopted to select the CSI process set by the base station.

  As can be seen, as shown in FIG. 3, after it is determined whether the fallback CSI needs to be set, the CSI process set by the base station is selected using the following method: . That is, when the traffic load is high, the CSI process set by the base station without using the fallback CSI is filled with the remaining CSI process corresponding to 3-TP CoMP (right diagonal line in FIG. 3). Is set by the remaining base station using fallback CSI (see the area filled with vertical lines in FIG. 3). The CSI process is selected from other CSI processes corresponding to 2-TP CoMP (refer to the area filled with the left diagonal line in FIG. 3). Here, 3-TP CoMP is a first CoMP measurement set, and 2-TP CoMP is a second CoMP measurement set.

  When the above method is adopted, when the load level is low, the performance advantage of 3-TP CoMP is not particularly obvious compared to 2-TP CoMP, but the scheduling complexity is much larger than that of 2-TP CoMP. Therefore, setting the CSI process corresponding to 2-TP CoMP when the load level is low can guarantee the system performance and reduce the complexity of measurement and scheduling. When the load level is high, the performance gain of 3-TP CoMP is much greater than 2-TP CoMP. In this case, selecting 3-TP CoMP can lead to higher system performance.

  In yet another specific embodiment of the present invention, as shown in FIG. 4, a first load threshold and a second load threshold are preset, wherein the first load threshold is a second load threshold. The threshold values are smaller than the threshold value, and both of the threshold values can be set by experience values or the like.

  Specifically, after acquiring the traffic load of the wireless communication system, the traffic load is compared with a preset first load threshold and a second load threshold, respectively, where the first load threshold is Less than the second load threshold. If the traffic load is smaller than the first load threshold, it is determined that the load level of the wireless communication system is low, and policy 1 is adopted to select the CSI process set by the base station. Policy 1 specifically selects the fallback CSI as one of the CSI processes set by the base station, and from other CSI processes corresponding to the serving base station, the CSI process set by the base station To choose the rest of. If the traffic load is greater than the second load threshold, it is determined that the load level of the wireless communication system is high, and policy 2 is adopted to select the CSI process set by the base station. Policy 2 specifically excludes fallback CSI from the CSI process set by the base station and sets at least one from the CSI process corresponding to each base station included in the CoMP measurement set by the base station. The CSI process is selected. If the traffic load is smaller than the first load threshold and greater than the second load threshold, it is determined that the load level of the wireless communication system is a medium level, and policy 3 is adopted to Select the CSI process set by. Policy 3 specifically selects fallback CSI as one of the CSI processes set by the base station, and at least one of the CSI processes corresponding to each coordinated base station included in the CoMP measurement set. As the rest of the CSI processes set by the base station. If the traffic load is equal to the first load threshold, policy 1 or policy 3 can be adopted to select the CSI process set by the base station, and if the traffic load is equal to the second load threshold, the policy 2 or policy 3 can be adopted to select the CSI process set by the base station.

  As can be seen, the traffic load is in the low region if it is less than the first load threshold, the traffic load is in the high region if it is greater than the second load threshold, and the corresponding traffic load region in FIG. Since this is similar to the process in FIG.

  When the traffic load of the system is in the middle level region, that is, when the traffic load is larger than the first load threshold and smaller than the second load threshold, the fallback CSI is set as the CSI process set by the base station. The CSI process that is always selected and set by the base station is selected from CSI processes corresponding to other base stations other than the serving base station in the CoMP measurement set. For example, the spare set 2 corresponding to TP2 And the spare set 3 corresponding to TP3. Specifically, according to the strongest SINR principle, a CSI process set by a base station can be selected from CSI processes corresponding to other base stations, and this process specifically refers to the following description. Referring to Table 2, in a specific implementation, when the system resource utilization is between two thresholds and is a moderate load, the CSI process that the base station sets for that CoMP user is CSI1 , CSI11, and CSI12.

  In the above embodiment, after the selection range of the CSI process is reduced by the load threshold, the base station determines whether the signal-to-interference plus noise ratio (SINR) of the CSI process is strong. Further selections can be made. Of course, if the user feeds back only three types of CSI processes, the base station may first update the CSI to obtain other types of CSI processes, and then make further selections based on the SINR. Good. For example, among the CSI processes corresponding to the base station A, the CSI process having the maximum SINR may be selected and requested to be fed back to the user, where the base station A is the serving base station, or It may be a coordinated base station or any base station in the CoMP measurement set.

  In a specific implementation, assume that the base station intends to set up three CSI processes for a CoMP user. When the base station discovers that the network is under low traffic load with a resource utilization below a preset threshold, first the fallback CSI (ie CSI1) is selected and then the remaining 2 Is selected from the CSI process corresponding to the CS scheme based on the strength of SINR, that is, selected from CSI2, CSI6, and CSI10. Assuming that the SINR magnitude relationship is CSI10> CSI2> CSI6, the base station can set CSI1, CSI10, and CSI2 to perform measurement and feedback for the CoMP user.

  When the base station detects that the network has a resource utilization higher than a preset threshold and is in a heavy traffic load, it can first determine that the fallback CSI is for the CoMP user Not selected. Then, the remaining CSI processes corresponding to the DPS scheme are selected based on the strength of SINR at each TP. Specifically, from CSI processes other than the fallback CSI of TP1 (ie, CSI2, CSI6, CSI10), CSI10 with the maximum SINR was selected, measured (or updated), and from TP2. From the four CSI processes (ie, CSI3, CSI4, CSI8, CSI11), the CSI11 having the maximum SINR is selected, and from the four CSI processes from the TP3 (ie, CSI5, CSI7, CSI9, CSI12), the SINR is maximized. Select CSI12. Finally, the base station configures CSI 10, CSI 11, and CSI 12 to perform measurement and feedback for the CoMP user.

  In another specific implementation, assume that the base station sets up more than three CSI processes for CoMP users. After selecting CSI10, CSI11, and CSI12 in a state where traffic load is high, any of the following methods can be adopted for selecting another CSI process. For example, from the unselected CSI process, select some of the maximum SINR, or from the CSI process from the serving cell TP1, select some of the maximum SINR, or CSI reserves from each TP From the set, the one having the maximum SINR is selected, and further selection is made based on the priority of each TP. For example, the priority of TP1 is higher than TP2, and TP2 is higher than TP3.

  After all the CSI processes set by the base station are selected, measurement setting is performed for the user by the selected CSI process set by the base station, and the subsequent user sets the corresponding CSI process to the base station. The base station performs scheduling using the received CSI process. Since the specific process can refer to the prior art, the description is omitted here.

  In another embodiment of the present invention, reference signal received power (RSRP), reference signal receiving quality (RSRQ), SINR, and SINR, which are measured and fed back by a user, are measured and fed back by a user. The CSI process set by the base station can be selected based on signal parameter differences such as

  For example, it can be stated that the greater the difference between the serving cell and cooperating cell signal parameters, the closer the user's location is to the serving cell and the greater the probability of scheduling to the serving cell. Therefore, more CSI processes corresponding to the serving cell are set for the user, in other words, the CSI process in the CS scheme is selected with a greater probability. Conversely, it is expressed that the smaller the difference, the closer the user is to the edge position and the closer the distance from the serving cell and the cooperative cell. In this case, since the probability that the user is scheduled to the serving cell and the cooperative cell is close, if the base station selects the CSI process for this CoMP user, the probability that the CSI process from the serving cell and the cooperative cell is selected is Nearly, in other words, the CSI process in the DPS scheme is set with a greater probability.

  Another embodiment of the present invention provides a method for selecting a channel state information (CSI) process for coordinated multipoint (CoMP) users in a wireless communication system, the flow of which refers to FIG.

  In step 501, a parameter difference between a serving cell signal parameter and a coordination cell signal parameter is determined. In step 502, the parameter difference is compared with one or more preset difference thresholds to determine the location of the CoMP user and for different user locations, a different base station set process. To decide. As can be seen from this, when the CoMP users have different positions in the serving cell, the policy for selecting the CSI process set by the base station is not the same.

  In a specific implementation, step 502 compares the parameter difference with a preset first difference threshold, and if the parameter difference is greater than the first difference threshold, the location of the CoMP user is the number of serving cells. The CSI process set by the base station from the CSI process corresponding to the serving base station, selecting the fallback CSI as one of the CSI processes set by the base station If the parameter difference is smaller than the first difference threshold, it is determined that the location of the CoMP user is located in the second edge region of the serving cell, and the fallback CSI is set by the base station For each base station included in the CoMP measurement set. Selecting at least one of the CSI processes as a CSI process configured by a base station, wherein the first edge region is closer to the center of the serving cell than the second edge region . In addition, when determining the CSI process set by the base station from the CSI process corresponding to each base station in the CoMP measurement set, the selection can be performed according to the strongest SINR principle.

  In a specific implementation, step 502 compares the parameter difference with a preset first difference threshold, and if the parameter difference is less than the first difference threshold, the location of the CoMP user is determined by the serving cell. At least one from the CSI process corresponding to each base station included in the first CoMP measurement set, determined to be located in the second edge region, excluding fallback CSI from the CSI process set by the base station If the parameter difference is greater than the first difference threshold, it is determined that the location of the CoMP user is located in the first edge region of the serving cell, and the fallback CSI is Select as one of the CSI processes set up by the base station, A second CoMP measurement set having a smaller number of stations than the first CoMP measurement set is newly generated, and a CSI set by the base station is obtained from a CSI process corresponding to the base station included in the second CoMP measurement set. Selecting the remainder of the process (e.g., the selection can be made according to the strongest SINR principle), wherein the first edge region is more central to the serving cell than the second edge region. close.

  In a specific implementation, step 502 compares the parameter difference with a preset first difference threshold and a second difference threshold, respectively, and if the parameter difference is greater than the first difference threshold, From the CSI process corresponding to the serving base station, determining that the location of the CoMP user is located in the first edge region of the serving cell, selecting the fallback CSI as one of the CSI processes set by the base station, If the remainder of the CSI process set by the base station is selected (eg, selection can be made according to the strongest SINR principle) and the parameter difference is less than the second difference threshold, the location of the CoMP user is Determined to be located in the second edge region of the serving cell and And at least one CSI process corresponding to each base station included in the CoMP measurement set is selected as a CSI process configured by the base station, and the parameter difference is the first CSI process. Is determined to be located in the third edge region of the serving cell and a fallback CSI is set by the base station. Select as one of the CSI processes corresponding to each coordinated base station included in the CoMP measurement set, and select at least one as the rest of the CSI processes set by the base station (e.g., SINR strongest). The choice can be made according to the principle), including The first difference threshold value is larger than the second difference threshold value, and the values of the two threshold values can both be set by experience values or the like, and the first edge region is the second difference threshold value. The third edge region is located between the first edge region and the second edge region, closer to the center of the serving cell than the edge region. That is, the first edge region is a region where the edge approaches the center, the third edge region is a relatively edge region, and the second edge region is the most edge region.

  Specifically, selecting a CSI process set by the base station from the CSI process corresponding to the base station determines a signal-to-interference noise ratio of each CSI process corresponding to the base station, and Selecting a predetermined number of CSI processes set by the base station in descending ratio order. The base station here may be a serving base station, a coordinated base station, or any base station included in the CoMP measurement set.

  In the above embodiment, the signal parameter includes reference signal reception power, reference signal reception quality, or signal-to-interference noise ratio.

  In still another embodiment of the present invention, each base included in the CoMP measurement set in the most common state among the states corresponding to the case where each user is scheduled in the past certain period or in the past certain period. Based on the situation when the station transmission is most frequent, the CSI process set up by the base station can be determined. Specifically, the method determines Nconf user scheduling states or base station transmission states having the highest appearance frequency within a predetermined time period, and determines the Nconf user scheduling states or base stations from a preliminary set of CSI processes. And searching for a CSI process corresponding to a transmission state to be a CSI process set by the base station, where Nconf is the number of CSI processes set by the base station, and the user scheduling state is The base station transmission state when the user is scheduled. The base station transmission state is a state in which any user is scheduled. Hereinafter, Nconf = 3 will be described as an example. That is, the base station attempts to set up three CSI processes to perform measurement and feedback for CoMP users. Assume the following: the most three of the states corresponding to the case where CoMP UE A is scheduled to transmit within the past 100 ms are 1 and TP1, respectively. TP2 and TP3 are in a non-muting state, 2, TP1 transmits data to CoMP UE A, TP2 is in a closing state, and TP3 is in an open state 3 , TP2 transmits data to CoMP UE A, TP1 is in the closed state and TP3 is in the open state. Specifically, when the TP is in the closed state (muting), the power of the data channel is 0, but the power of the control channel is not 0. When the TP is in a non-muting state, neither the data channel nor the control channel power is zero. In this case, the three CSI processes set by the base station for CoMP UE A are CSI1, CSI2, and CSI4 in Table 1. As should be explained, in this example, the three most frequent states corresponding to the scheduled case are not involved in data transmission from TP3, or TP3 is merely interference. Therefore, the CSI process set by the base station can be selected from Table 1 for 2-TP CoMP. In other cases, the CSI process set by the base station can be selected from Table 2 for 3-TP CoMP based on the most common state corresponding to when each user is scheduled. .

  Any of the selection methods according to the embodiments of the present invention can be executed by the base station. Accordingly, a corresponding function needs to be added to the base station so as to realize any one or a plurality of selection methods.

  In a specific embodiment of the present invention, a base station for selecting a channel state information (CSI) process is provided for cooperative multipoint (CoMP) users, and the configuration is as shown in FIG. A first means 601 for obtaining a traffic load of the system, and comparing the traffic load with one or more preset load thresholds to determine a load level of the wireless communication system and to a different load level; On the other hand, a second means 602 for determining different CSI processes set up by the base station.

  In the above base station, the second means 602 is implemented by referring to the method shown in FIG. 2. Specifically, the second means 602 calculates the traffic load and a preset first load threshold value. In comparison, if the traffic load is less than the first load threshold, it is determined that the load level of the wireless communication system is low, and fallback CSI is selected as one of the CSI processes set by the base station. If the remaining CSI process set by the base station is selected from the CSI processes corresponding to the serving base station, and the traffic load is greater than the first load threshold, the load level of the wireless communication system is Determined to be high and fallback CSI excluded from the CSI process set by the base station and included in the CoMP measurement set From CSI process corresponding to a base station, selecting at least one as a CSI process set by the base station.

  As to be described, the second means 602 may be realized by adopting the method shown in FIG. 3 and FIG.

  In another specific embodiment of the present invention, a base station for selecting a channel state information (CSI) process is provided for cooperative multipoint (CoMP) users, wherein the serving cell signal parameter and the cooperative cell signal parameter are: Comparing the parameter difference with one or more preset difference thresholds to determine the position of the CoMP user, and for different user positions A second means for determining different CSI processes set by the base station.

  In the above base station, the second means specifically compares the parameter difference with a preset first difference threshold, and if the parameter difference is larger than the first difference threshold, the CoMP From the CSI process corresponding to the serving base station, the base station determines that the user's location is located in the first edge region of the serving cell, selects the fallback CSI as one of the CSI processes set by the base station, Selecting the rest of the CSI processes set by the station and determining that the location of the CoMP user is located in the second edge region of the serving cell if the parameter difference is less than the first difference threshold; Each base included in the CoMP measurement set is excluded from the CSI process set by the base station. Selecting at least one of the CSI processes corresponding to the station as a CSI process configured by the base station, wherein the first edge region is more of the serving cell than the second edge region. Near the center.

  The above is only an exemplary explanation for realizing the second means, and all the selection methods according to the method embodiment of the present invention can be realized by adopting a similar method. Description is omitted.

  In yet another specific embodiment of the present invention, a base station for selecting a channel state information (CSI) process is provided for cooperative multipoint (CoMP) users, and the frequency of occurrence is highest within a predetermined time period. A first means for determining Nconf user scheduling states or base station transmission states, and searching for a CSI process corresponding to the Nconf user scheduling states or base station transmission states from a preliminary set of CSI processes; And a second means to be a CSI process set by the NSI, wherein the Nconf is the number of CSI processes set by the base station.

  The method provided in the embodiment of the present invention, when the base station determines the number Nconf of measurement CSI processes to be set for the user, determines the appropriate CSI process based on each parameter and state of the system. By selecting and setting for the user, the system can achieve higher performance under various traffic loads. In addition, since the CoMP scheme can be selected according to the wireless environment, the embodiment of the present invention reduces the complexity of system measurement and network scheduling, and particularly reduces the complexity of the system when the load level is low. At the same time, system performance can be guaranteed.

The above are only preferred embodiments of the present invention and do not limit the protection scope of the present invention. Various modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present invention should all be included in the protection scope of the present invention.

Claims (16)

A method for selecting a channel state information (CSI) process for cooperative multipoint (CoMP) users in a wireless communication system, comprising:
A1 from which the base station acquires the traffic load of the wireless communication system;
The base station compares the traffic load with one or more preset load thresholds to determine the load level of the wireless communication system and is set by different base stations for different load levels and B1 to determine the CSI process that is, only including,
B1 is
Comparing the traffic load with a preset first load threshold;
If the traffic load is greater than the first load threshold, it is determined that the load level of the wireless communication system is high, the fallback CSI is excluded from the CSI process set by the base station, and the first CoMP measurement set Selecting at least one as a CSI process configured by the base station from CSI processes corresponding to each base station included in
The method of claim 1, wherein the first CoMP measurement set includes a serving base station and all cooperative base stations . The B1 is,
If the traffic load is less than the first load threshold, determine that the load level of the wireless communication system is low, select a fallback CSI as one of the CSI processes set by the base station, and serve from CSI process corresponding to the base station, you select the rest of the CSI process set by the base station, the method according to claim 1, characterized by further comprising. The B1 is,
If the traffic load is less than the first load threshold, determine that the load level of the wireless communication system is low, select a fallback CSI as one of the CSI processes set by the base station, and A second CoMP measurement set having a smaller number of stations than the first CoMP measurement set is newly generated, and a CSI set by the base station is obtained from a CSI process corresponding to the base station included in the second CoMP measurement set. The method of claim 1, further comprising selecting a remainder of the processes. B1 is
A second load threshold that the preset traffic load and comparing,
If the traffic load is less than the second load threshold, it determines that the load level of the wireless communication system is low, selects fallback CSI as one of the CSI processes set by the base station, and serves From the CSI process corresponding to the base station, select the rest of the CSI processes configured by the base station ;
When the traffic load is larger than the second load threshold and smaller than the first load threshold, the load level of the wireless communication system is determined to be a medium level, and the fallback CSI is set by the base station. Select as one of the processes and select at least one of the CSI processes corresponding to each coordinated base station included in the first CoMP measurement set as the rest of the CSI processes configured by the base station Further comprising
2. The method of claim 1, wherein the second load threshold is less than the first load threshold. Selecting the CSI process set by the base station from the CSI process corresponding to the base station is
Determining a signal-to-interference and noise ratio for each CSI process corresponding to the base station, and selecting a predetermined number of CSI processes set by the base station in descending order of the signal-to-interference and noise ratio. The method according to any one of claims 2 to 4.   The method according to claim 1, wherein the traffic load includes a resource usage rate and / or a number of users. A method for selecting a channel state information (CSI) process for cooperative multipoint (CoMP) users in a wireless communication system, comprising:
A2 in which the base station determines a parameter difference between the signal parameter of the serving cell and the signal parameter of the cooperative cell;
The base station compares the parameter difference with one or more preset difference thresholds to determine the position of the CoMP user and is set by different base stations for different user positions and B2 to determine the CSI process, only including,
B2 is
Comparing the parameter difference with a preset first difference threshold;
If the parameter difference is less than the first difference threshold, determine that the location of the CoMP user is located in the second edge region of the serving cell, and exclude fallback CSI from the CSI process set by the base station; Selecting at least one as a CSI process configured by the base station from CSI processes corresponding to each base station included in the first CoMP measurement set;
The method of claim 1, wherein the first CoMP measurement set includes a serving base station and all cooperative base stations . The B2 is,
If the parameter difference is greater than the first difference threshold, it is determined that the location of the CoMP user is located in the first edge region of the serving cell, and fallback CSI is one of CSI processes set by the base station is selected as from CSI process corresponding to the serving base station, you select the rest of the CSI process set by the base station, further comprising,
8. The method of claim 7, wherein the first edge region is closer to the center of the serving cell than the second edge region. The B2 is,
If the parameter difference is greater than the first difference threshold, it is determined that the location of the CoMP user is located in the first edge region of the serving cell, and fallback CSI is one of CSI processes set by the base station A second CoMP measurement set having a smaller number of base stations than the first CoMP measurement set is generated, and from the CSI process corresponding to the base stations included in the second CoMP measurement set, Further comprising selecting the rest of the CSI processes set by the station;
8. The method of claim 7, wherein the first edge region is closer to the center of the serving cell than the second edge region. B2 is
And the parameter difference and a second difference threshold value set in advance by comparison,
If the parameter difference is greater than the second difference threshold, it is determined that the location of the CoMP user is located in the first edge region of the serving cell, and fallback CSI is one of CSI processes set by the base station And select from the CSI processes corresponding to the serving base station the rest of the CSI processes configured by the base station ,
If the parameter difference is smaller than the second difference threshold and greater than the first difference threshold, it is determined that the location of the CoMP user is located in a third edge region of the serving cell, and the fallback CSI is determined as a base station Of CSI processes configured by the base station, selecting at least one of the CSI processes corresponding to each cooperative base station included in the first CoMP measurement set as one of the CSI processes configured by Further selecting that as the rest of them,
Here, the second difference threshold is larger than the first difference threshold, the first edge region is closer to the center of the serving cell than the second edge region, and the third edge region is The method of claim 7, wherein the method is located between the first edge region and the second edge region. Selecting the CSI process set by the base station from the CSI process corresponding to the base station is
Determining a signal-to-interference and noise ratio for each CSI process corresponding to the base station, and selecting a predetermined number of CSI processes set by the base station in descending order of the signal-to-interference and noise ratio. The method according to any one of claims 8 to 10.   The method according to claim 7, wherein the signal parameter includes a reference signal reception power, a reference signal reception quality, or a signal to interference noise ratio. A base station that selects a channel state information (CSI) process for cooperative multipoint (CoMP) users,
A first means for obtaining a traffic load of the wireless communication system;
The traffic load is compared with one or more preset load thresholds to determine the load level of the wireless communication system, and different CSI processes set by the base station for different load levels. A second means for determining ,
The second means includes
Comparing the traffic load with a preset first load threshold;
If the traffic load is greater than the first load threshold, it is determined that the load level of the wireless communication system is high, the fallback CSI is excluded from the CSI process set by the base station, and the first CoMP measurement set Selecting at least one of the CSI processes corresponding to each base station included in the CSI process set by the base station;
The base station, wherein the first CoMP measurement set includes a serving base station and all cooperative base stations. It said second means,
If the previous SL traffic load is less than said first load threshold, the determined load level of the radio communication system is low, is selected as one of the CSI process set fallback CSI by the base station, the base station according to claim 1 to 3, the CSI process corresponding to the serving base station, you select the rest of the CSI process set by the base station, characterized in that. A base station that selects a channel state information (CSI) process for cooperative multipoint (CoMP) users,
A first means for determining a parameter difference between the serving cell signal parameter and the cooperative cell signal parameter;
Compare the parameter difference with one or more preset difference thresholds to determine the location of the CoMP user and to determine different CSI processes set by the base station for different user locations A second means ,
The second means includes
Comparing the parameter difference with a preset first difference threshold;
If the parameter difference is less than the first difference threshold, determine that the location of the CoMP user is located in the second edge region of the serving cell, and exclude fallback CSI from the CSI process set by the base station; Selecting at least one CSI process configured by the base station from the CSI processes corresponding to each base station included in the first CoMP measurement set;
The base station, wherein the first CoMP measurement set includes a serving base station and all cooperative base stations. It said second means,
If the parameter difference is greater than the first difference threshold, it is determined that the location of the CoMP user is located in the first edge region of the serving cell, and fallback CSI is one of CSI processes set by the base station And select from the CSI processes corresponding to the serving base station the rest of the CSI processes configured by the base station ,
In here, the first edge region, than the second edge region near the center of the serving cell, the base station according to claim 1 5, characterized in that.

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