JP6404000B2 - Scheduling method and scheduling device for cell - Google Patents

Description

  The present invention relates to the field of wireless communications, and in particular, to a scheduling method and a scheduling device for a cell.

  In coordinated multipoint (CoMP) transmission technology, a cell is transmitted to / received from a mobile station in a manner in which a serving cell and a plurality of cells (or base stations) including neighboring cells of the serving cell cooperate with each other. Thereby improving the throughput of the communication system by reducing the interference between them and improving the received signal quality of the base station / mobile station. This requires coordinated scheduling among multiple cells. Centralized coordinated scheduling methods have already been proposed, in which the central scheduler centrally processes scheduling information (eg channel state information) for each cell, and based on these information, Intensive scheduling of cells. However, since it is necessary to perform processing and scheduling for a plurality of cells at the same time, such a centralized scheduling method is complicated, and a high request is required for the processing capability of the central scheduler.

  In order to solve the above problem, distributed coordinated scheduling has been proposed. Instead of centrally scheduling a plurality of cells, a single scheduler is installed in each cell to schedule the cell. Like that. Distributed cooperative scheduling is less complex and reduces the demands on scheduler processing power. Two types of distributed cooperative scheduling methods have already been developed, enhanced inter-cell interference coordination (eICIC) and fractional frequency repetition (FFR). The eICIC method can be used for time domain coordinated scheduling in heterogeneous networks, and the FFR method can be used for frequency domain coordinated scheduling in homogeneous networks. However, both of these two methods are semi-static cooperative scheduling methods. For example, in FFR, scheduling is performed at a long time interval (for example, several hundred milliseconds), but this makes it impossible for the scheduling result to cope with a rapid change in the wireless environment, and the performance gain provided to the system is limited.

  Therefore, there is a need for a method and device that dynamically performs distributed scheduling in a multi-cell coordination situation.

  The present invention is proposed in consideration of the above problems. The present invention can perform dynamic scheduling for each cell in a distributed manner in the situation of multi-cell cooperation, and the scheduling result can cope with changes in the radio environment, thereby effectively improving the system performance. One object is to provide a scheduling method and a scheduling device for a cell.

  According to one aspect of the present invention, there is provided a scheduling method for a cell, comprising: determining an on / mute state on a plurality of frequency resources of the cell; and a neighboring cell of the cell and each of the plurality of cells Exchanging on / mute states on frequency resources, various channel state information fed back by users of the cells, and neighboring cells scheduling based on on / mute states on the plurality of frequency resources A method comprising the steps of:

  According to another aspect of the present invention, there is provided a scheduling device for a cell, a pre-scheduling device for determining an on / mute state on a plurality of frequency resources of the cell, an adjacent cell of the cell, and each cell. A communication device for exchanging on / mute states on the plurality of frequency resources, various channel state information fed back by a user of the cell, and on / mute states on the plurality of frequency resources of the neighboring cell. Provided is a device having a scheduling apparatus for performing scheduling based on the scheduling apparatus.

  According to the scheduling method and scheduling device of the above aspect of the present invention, it is possible to perform scheduling independently for each cell in the frequency domain, instead of performing intensive scheduling for a plurality of cells. Does not require very high processing power. Further, according to the scheduling method and the scheduling device of the above aspect of the present invention, scheduling can be performed at a considerably short time interval (for example, 1 millisecond), and channel state information fed back by the user when performing scheduling is considered. Since the channel state information reflects dynamic changes in the radio environment, the scheduling result can further cope with changes in the radio environment compared to the conventional semi-static scheduling method, and the performance of the communication system To improve.

The above and other objects, features, and merits of the present invention will become more apparent by describing embodiments of the present invention in detail with reference to the drawings.
An application scene of an embodiment of the present invention is exemplarily shown. FIG. 3 is a flow diagram of a scheduling method for a cell according to the first embodiment of the present invention. FIG. 3 is a flowchart of detailed operations in step S201 shown in FIG. FIG. 6 is a detailed operation flow diagram in which the cell according to the second embodiment of the present invention establishes on / mute states on a plurality of frequency subbands. FIG. 6 is a detailed operation flow diagram in which the cell according to the third embodiment of the present invention establishes on / mute states on a plurality of frequency subbands. FIG. 3 is a block diagram illustrating a scheduling device for a cell according to an embodiment of the present invention. FIG. 7 is a block diagram illustrating an exemplary structure of the scheduling apparatus 603 shown in FIG. 6. FIG. 7 is a block diagram showing a first exemplary structure of the pre-scheduling apparatus 601 shown in FIG. FIG. 7 is a block diagram showing a second exemplary structure of the pre-scheduling apparatus 601 shown in FIG. FIG. 7 is a block diagram showing a third exemplary structure of the pre-scheduling apparatus 601 shown in FIG.

  Hereinafter, a scheduling method and a scheduling device for a cell according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals denote the same components throughout. It should be understood that the embodiments described herein are illustrative only and should not be construed as limiting the scope of the invention.

  First, an exemplary application of an embodiment of the present invention will be described with reference to FIGS. 1A and 1B.

  FIG. 1A shows a first exemplary application scenario. The scene is based on a centralized radio access network (C-RAN) architecture, and a control unit (e.g., baseband unit (BBU)) and a plurality of (for simplicity, three in FIG. 1A) are connected to the baseband unit. A centralized base station eNB is formed by remote radio heads (RRH) (shown), and each RRH can form one cell. These three cells constitute a CoMP cooperative group. One BBU can be installed for each cell (or RRH), and the BBU can perform scheduling corresponding to the cell as a scheduler. FIG. 1B shows a second exemplary application scenario, where three base stations eNB each form three cells. These three cells form a cooperative group. One scheduler (not shown in the figure) can be installed in each eNB to schedule the corresponding cell. Although only three RRHs and three eNBs are shown in FIGS. 1A and 1B, the number of RRHs and eNBs is not limited to three, and may be any appropriate quantity determined based on actual demand. You must recognize that.

  Next, a scheduling method for a cell according to the first embodiment of the present invention will be described with reference to FIG. As described above, the method may be performed by a scheduler or BBU (eg, BBU1, BBU2, or BBU3 shown in FIG. 1A) for each cell so that the corresponding cell can be scheduled, thereby enabling multi-cell coordination. To achieve distributed scheduling. In the embodiments of the present invention, frequency subbands or resource blocks are examples of the frequency resources. However, it should be recognized that the frequency resources may be other types of frequency resources used as a basic unit of scheduling. I must.

  As shown in FIG. 2, for a cell to be scheduled, in step S201, the cell determines an on / mute state on a plurality of frequency subbands. In the following description, for convenience of explanation, a cell that is scheduled to execute the current scheduling is called a serving cell.

  In the CoMP transmission technique, interference between cells is reduced by performing coordinated scheduling to coordinate transmission and reception of each cell with respect to a plurality of cells belonging to the same coordination group. In an embodiment of the present invention, one or more cells of the plurality of cells are selectively muted for each frequency subband in the plurality of frequency subbands, i.e., the one. Alternatively, the interference received by other cells can be reduced by not allowing more cells to transmit data in the frequency subband. Therefore, it is necessary to determine whether each cell is on / muted (or on / muted pattern) on each frequency subband, ie whether each cell is on or muted on each frequency subband. Yes, this may be referred to as cell pre-scheduling.

  Hereinafter, a method of determining the on / mute state on the plurality of frequency subbands in step S201 by the serving cell will be described in more detail with reference to FIG.

  As shown in FIG. 3, in step S2011, the performance loss of the serving cell when the serving cell is muted on each frequency subband in the plurality of frequency subbands is calculated.

Specifically, if there are n frequency subbands in total, the maximum performance P _{max of the} serving cell that can be obtained when the serving cell does not mute any of the n frequency subbands may be calculated. . For this purpose, scheduling may be performed on each frequency subband to determine a user to be assigned to each frequency subband. For example, for each frequency subband, the performance corresponding to the user is calculated based on CSI (as described below) fed back by each user of the serving cell, and the user with the best performance is It can be a user assigned to a subband. And the sum of the performance of the serving cell which the user allocated to each frequency subband can acquire by communication is approximated, and this corresponds to the maximum performance of the serving cell. The performance may be a cell throughput. In this case, a sum of throughputs realized by users allocated on each frequency subband may be calculated to obtain the maximum performance of the serving cell. Methods for estimating the serving cell performance obtainable on each frequency subband are known in the art and will not be described here.

Subsequently, the performance of the serving cell when the serving cell is muted on each frequency subband in the plurality of frequency bands may be calculated. Specifically, the cell performance P _{sb1 -mute} when the serving cell is muted on the first frequency subband in the n frequency subbands may be calculated. For example, scheduling is performed on each frequency subband other than the first frequency subband, a user assigned to each other frequency subband is determined, and each frequency other than the first frequency subband is determined. The serving cell performance P _{sb1 -mute that} can be acquired by communication by users allocated on the subband may be calculated. _Similarly , the serving cell performance P _{sb2 -mute} , P _{sb3 -mute that} can be obtained when the serving cell is muted on the second frequency subband, the third frequency subband, ... the nth frequency subband. ,..., P _sbn-mute may be calculated.

Then, based on the maximum performance P _max of the serving cell and the cell performance P _{sb1 -mute} , P _{sb2 -mute} , P _{sb3 -mute} ,..., P _sbn-mute when the serving cell is muted on each frequency subband, Cell performance loss may be calculated when the serving cell is muted on each frequency subband. In an embodiment of the present invention, cell performance P _{sb1 -mute} , P _{sb2 -mute} , P _{sb3 -mute} ,..., P _sbn-mute and the maximum performance P when the serving cell is muted on each frequency subband. ratio _{r sb1-mute} during _{max, r sb2-mute, r} sb3-mute, ..., may be calculated, respectively _{r sbn-mute,} the ratio that the serving cell is muted on each frequency subband Since the degree of reduction in cell performance with respect to the maximum performance P _max can be reflected, the performance loss can be reflected indirectly. In another embodiment, the maximum serving cell performance P _max and the cell performance when the serving cell is muted on each frequency subband P _{sb1 -mute} , P _{sb2 -mute} , P _{sb3 -mute} ,..., P _sbn− It calculates the difference between the _mute, and the ratio between the respective differences between the maximum performance P _max may directly reflect the performance loss. In yet another embodiment, the respective differences may be directly used as the performance loss.

Subsequently, in step S2012, based on whether the serving cell performance loss exceeds the loss threshold when the serving cell is muted on each frequency subband, the serving cell is on / muted on the frequency subband. Confirm. In an embodiment of the present invention, the ratios r _sb1-mute , r _sb2-mute , r _sb3-mute ,..., R _sbn-mute are respectively compared with the ratio threshold r _threshold and whether or not the performance loss exceeds the loss threshold. Confirm. However, the loss threshold may be calculated as 1-rthreshold. For example, when the ratio r _sbi-mute corresponding to frequency subband i (1 ≦ i ≦ n) is greater than the ratio threshold r _threshold , this means that if the serving cell is muted on frequency subband i, the performance loss of the serving cell is This means that the serving cell is on / off on the frequency subband since it means that the effect on the performance of the serving cell by muting the serving cell on the frequency subband is relatively small. It may be determined that the mute state is mute. On the other hand, when the ratio r _sbi-mute is less than the ratio threshold r _threshold , this means that if the serving cell is muted on frequency subband i, the performance loss of the serving cell will be greater than the loss threshold, ie the frequency sub It means that muting the serving cell on the band has a relatively large effect on the performance of the serving cell, so it may be determined that the serving cell should not be muted. As can be seen from the above, the larger the ratio threshold, i.e., the smaller the loss threshold, the more the serving cell is muted on a few frequency subbands. Conversely, the smaller the ratio threshold, i.e., the larger the loss threshold, the serving cell. Are muted on many frequency subbands. The ratio threshold may be flexibly set based on design demand and / or other factors. The ratio threshold can be set to a fixed value. For example, the ratio threshold can be set to (n−1) / n. This means that the serving cell is muted on at least one frequency subband. Alternatively, the ratio threshold can be set to 0.95 (the corresponding loss threshold is 5%). Thus, when the ratio r _sbi-mute exceeds 95%, the cell is muted on the frequency subband i, otherwise the cell is turned on on the frequency subband i. In addition, the ratio threshold value can be set to a variable value. For example, set the ratio threshold to a value that changes dynamically based on the traffic load of the network and increase the ratio threshold when the traffic load is relatively large, which may cause the cell to mute on it When the frequency subband is reduced and the traffic load is relatively small, the ratio threshold is decreased, thereby increasing the frequency subband on which the cell may be muted.

  By performing the operation shown in FIG. 3 for each frequency subband, the on / mute state on each frequency subband of the cell can be determined.

  Returning to FIG. 2, in step S202, the on / mute state (or on / mute pattern) on each of the plurality of frequency subbands with the neighboring cell of the serving cell is exchanged. For example, the on / mute state on each of the plurality of frequency subbands is exchanged between a serving cell and an adjacent cell through a backhaul circuit. In this way, each cell that cooperates intensively can know the on / mute state on each frequency subband of another cell.

  After that, in step S203, scheduling is performed based on various channel state information fed back by the user (mobile station) of the serving cell and on / mute states on the plurality of frequency subbands of neighboring cells.

  Specifically, in order to perform scheduling for each serving cell user (mobile station) for each frequency subband, it is necessary to know the radio channel condition between the user and the serving cell base station. For this purpose, channel state information (CSI) reflecting the radio channel condition, for example, channel quality indicator (CQI) may be fed back from the user to the base station. In an embodiment of the present invention, for each frequency subband, various CSIs corresponding to different on / mute states of the serving cell and the neighboring cell may be fed back from the user. For example, if the coordination group includes multiple cells, these cells may have various on / mute states such as all on, all muted, and partially on and partially muted. Different on / mute states of the serving cell and the neighboring cells may be all or part of these on / mute states. Specifically, the user may calculate CSI corresponding to all or a part of these on / mute states and feed it back to the serving cell (base station). Since a specific method for calculating the CSI corresponding to various on / mute states by the user is known in the art, it will not be described here. In an embodiment of the present invention, the user may be a neighboring user of the serving cell, and in another embodiment, the user may be any user of the serving cell.

  Since the on / mute state on each frequency subband of the neighboring cell of the serving cell is already known in step S202, the neighboring cell is turned on from the various CSIs fed back by the user for each frequency subband. / CSI corresponding to the mute state may be selected, and scheduling may be performed based on the selected CSI. For example, the user selects the MCS level assigned to the frequency subband, and the user transmits data using the MCS level. For example, if the coordination group includes two cells (ie, a serving cell and one neighboring cell), the serving cell is on / muted on for any frequency subband and the neighboring cell is on / muted. If muted, the scheduling may be performed by selecting the CSI corresponding to the state in which the serving cell is on and the neighboring cell is muted from various CSIs fed back by the user. As another example, when the coordinated group includes three cells (serving cell, adjacent cell 1 and adjacent cell 2), the serving cell on / mute state is on for any frequency subband, and the adjacent cell If the on / mute state of 1 is on, the on / mute state of adjacent cell 2 is mute, and the user's cooperative cell assigned to the frequency subband is cell 3, the user assigned to the frequency subband is The scheduling cell may be selected based on the CSI selected from the various CSIs to be fed back by selecting the CSI corresponding to the state in which the serving cell is on, the neighboring cell 1 is on, and the neighboring cell 2 is muted.

  In the scheduling method according to the first embodiment of the present invention, scheduling is performed based on various channel state information fed back by the user and on / mute states on the plurality of frequency subbands of adjacent cells, and the user selects by scheduling. Scheduling is performed so that the MCS level can better cope with the radio channel state when scheduling, that is, the scheduling result can be more favorably adapted to changes in the radio environment, thereby improving system performance, for example, system throughput. Improve.

It should be appreciated that the scheduling method according to the first embodiment of the present invention described above is illustrative and not limiting. Those skilled in the art can make changes based on the design demands without departing from the spirit and scope of the present invention. For example, in step S201, the serving cell calculates a serving cell performance loss when the serving cell is muted on one frequency subband, and the serving cell determines whether the serving cell has the frequency subband based on whether the performance loss exceeds a loss threshold. Confirm the on / mute status of the band. Alternatively, calculate the serving cell's performance loss when the serving cell is muted on two or more frequency subbands, and based on whether the performance loss exceeds a loss threshold, the serving cell On / mute states on two or more frequency subbands may be established. In this case, calculate the maximum performance P _max of the serving cell as described above, and calculate the performance of the serving cell when the serving cell is muted simultaneously on the two or more frequency subbands, so that the serving cell The serving cell performance loss when simultaneously muted on two or more frequency subbands may be obtained. Thereafter, the serving cell may determine an on / mute state on the two or more frequency subbands based on whether the performance loss exceeds a loss threshold. For example, when the performance loss exceeds a loss threshold, it may be determined that the serving cell is turned on on the two or more frequency subbands, and when the performance loss does not exceed the loss threshold. , It may be determined that the serving cell has been muted simultaneously on the two or more frequency subbands. The loss threshold may be set as described above and will not be described here.

  In the scheduling method according to the first embodiment of the present invention, when the serving cell determines the on / mute state on the plurality of frequency subbands in step S201, only the serving cell information (for example, CSI) is considered, Do not consider information. From the viewpoint of the entire cooperative group, the on / mute state determined in this way is not necessarily the most appropriate. Specifically, the method attempts to mute the serving cell and reduce interference to neighboring cells after ensuring that the performance loss of the serving cell itself is relatively small, but determines the on / mute state. Sometimes the neighbor cell is not taken into account, so when the on / mute state of the serving cell is determined to be mute on any frequency subband, two types of results may occur: (1) the serving cell is muted This reduces the performance of the serving cell, but neighboring cells can gain a relatively large performance gain, and in this case, the determined on / mute state is appropriate from the viewpoint of the entire cooperative group. Can be recognized. (2) When the serving cell is muted, the performance of the serving cell is degraded, and at the same time, the self-sacrifice of the serving cell cannot bring a relatively large performance gain to the neighboring cell, and in this case the determined on / mute state Is inappropriate. To solve this problem, a scheduling method according to the second embodiment of the present invention is proposed, in which information from neighboring cells is taken into account when determining the on / mute state of the serving cell.

  Compared with the steps S201-S203 of the scheduling method according to the first embodiment of the present invention, the difference between the method according to the second embodiment of the present invention is that the step S201 (ie, the on-frequency on each frequency subband of the serving cell). Only the specific form of executing (/ determining the mute state) is different. For simplification, only the different points will be described below, and detailed description of the same parts will be omitted.

  FIG. 4 shows a specific form of step S201 (that is, the serving cell determines the on / mute state on the plurality of frequency subbands) in the scheduling method for the cell according to the second embodiment of the present invention.

  As shown in FIG. 4, in step S2011 ', pre-scheduling is performed for each frequency subband in the plurality of frequency subbands, and a user assigned to the frequency subband is determined. The user assigned to each frequency subband may be determined by the method described with reference to FIG.

  Subsequently, in step S2012 ′, for each frequency subband, it is determined whether or not the assigned user is a neighboring user. If the assigned user is a neighboring user, the cooperative cell (neighboring cell) of the neighboring user is determined. The cooperative cell transmits a mute request for requesting mute on the frequency subband. It should be noted that if the user assigned to any frequency subband is not a neighboring user, the mute request is not transmitted, in other words, step S2012 ′ may not be executed for the frequency subband. . Whether or not the assigned user is a peripheral user can be determined by any method known in the art, and detailed description thereof is omitted.

  Thereafter, in step S2013 ', a mute request is received from the neighboring cell so that the serving cell is muted on the frequency subband. Specifically, since neighboring cells that cooperate in a centralized manner also perform the scheduling method according to the second embodiment of the present invention, the neighboring cells may transmit the mute request to the serving cell. The serving cell may receive mute requests from neighboring cells.

  Subsequently, in step S2014 ', the on / mute state of the serving cell on the frequency subband is determined based on the number of mute requests transmitted and the number of mute requests received.

  Specifically, a counter may be installed for each frequency subband, and its initial value may be set to 0. Each time the serving cell sends a mute request to another cell, the counter value is set to 1. Each time the serving cell receives a mute request from a neighboring cell, the counter value may be incremented by one. Accordingly, the value of the counter is the difference between the number of mute requests received by the serving cell and the number of mute requests transmitted, and the serving cell determines the on / mute state on the frequency subband using the counter value. Also good. For example, one quantity threshold is set, and whether or not the serving cell should be muted on the frequency subband is determined according to whether the counter value exceeds the quantity threshold. The quantity threshold may be flexibly set to any appropriate value depending on various factors (for example, cell density). Preferably, the quantity threshold is set to a value of 1 or more, for example, 1 or 2. In the example in which the quantity threshold is set to 1, for any frequency subband, if the value of the counter exceeds the quantity threshold 1, the received mute request is at least one more than the mute request transmitted, in other words, the serving cell This means that the number of neighbor cells that claim to mute is greater than the number of neighbor cells that are mute charged to the serving cell, so that the serving cell is muted to get a larger performance gain, and in the opposite case, the serving cell is turned on. To obtain a large performance gain from the serving cell. It can be seen that as the quantity threshold value to be set is larger, the serving cell is less likely to be muted, in other words, less cells are muted in each cell of the cooperative group.

  After the serving cell has determined the on / mute state on each frequency subband as described above, the same steps as steps S202 and S203 described with reference to FIG. 2 may be performed. Implement scheduling. It will not be described here.

  In the scheduling method according to the second embodiment of the present invention, the on / mute state of the serving cell is determined in consideration of the relative number of mute requests transmitted from the serving cell to the neighboring cell and mute requests transmitted from the neighboring cell to the serving cell. To do. As a result, since the influence on the performance of the neighboring cell is taken into consideration when determining the on / mute state of the serving cell, it is possible to prevent the adverse effect on the performance of the neighboring cell as much as possible.

  Hereinafter, a scheduling method for a cell according to a third embodiment of the present invention will be described. Compared with each step S201-203 in the scheduling method according to the first embodiment of the present invention, the method according to the third embodiment of the present invention differs from the step S201 in step S201 (ie, on each frequency subband of the serving cell). Only the specific form of executing (determining the on / mute state) is different, and also considers information from neighboring base stations. For simplification, only the different points will be described below, and the description of the same parts will be omitted.

  Hereinafter, in the scheduling method for a cell according to the third embodiment of the present invention with reference to FIG. 5, step S201 (that is, the on / mute state on each frequency subband of the serving cell is determined) is executed. A specific form will be described.

  As shown in FIG. 5, in step S2011 ″, pre-scheduling is performed for each frequency subband in the plurality of frequency subbands, and a user to be assigned to the frequency subband is determined. The user assigned to each frequency subband may be determined by the method described with reference to FIG.

  In step S2012 ″, for each frequency subband, it is determined whether or not the assigned user is a neighboring user. If the assigned user is a neighboring user, the first information is stored in the cooperative cell of the neighboring user. Send. However, the first information indicates performance amplification (compared to when the cooperative cell is not muted) that is provided to the cell when the cooperative cell is muted on the frequency resource.

Specifically, a performance amplification table is defined in advance for each frequency subband, and a plurality of overall ranges of performance amplification obtained by mute of other cells by each cell that cooperates intensively on the frequency subband. And each section may be indicated by corresponding multiple bit information. For example, the entire performance amplification range is divided into four sections, and each section is indicated by a 2-bit value. In this case, one example of the performance amplification table is as shown in Table 1 below.

  Thus, when scheduling a serving cell, if the user assigned for any frequency subband is a neighboring user, determine the performance amplification that the serving cell can acquire when the user's cooperative cell is muted, And the information indicating the performance amplification corresponding to the cooperative cell based on the performance amplification table (that is, the first information) is transmitted, and when the cooperative cell receives the first information, Based on the performance amplification table, it is possible to know the performance amplification to be provided to the serving cell when self is muted. For example, when the performance amplification is 4, a binary value “10” is transmitted to the cooperative cell as the first information, and the self mute is brought to the serving cell to the cooperative cell that has received the binary value. It is acquired that the performance amplification is in the section (3, 5). It should be noted that if the user assigned to any one of the frequency subbands is not a neighboring user, the first information is not transmitted, in other words, step S2012 '' may not be executed for the frequency subband.

  Subsequently, in step 2013 '', the second information from the adjacent cell is received. The second information indicates the performance amplification provided to the neighboring cell when the serving cell is muted on the frequency subband. Specifically, since neighboring cells that perform intensive cooperation also implement the scheduling method according to the third embodiment of the present invention, when the neighboring cell is also muted to the serving cell by the above method on the frequency subband. The information indicating the performance amplification to be provided to the neighboring cell, that is, the second information is transmitted. Correspondingly, the serving cell may receive the second information.

  Thereafter, in 2014 ″, the on / mute state of the cell on the frequency subband is determined based on the first information and the second information. For example, for the frequency band, when the performance amplification (or the sum of performance amplification) indicated by the first information transmitted by the serving cell is smaller than the performance amplification (or the sum of performance amplifications) indicated by the second information received from the neighboring cell Determines that the serving cell is on / muted on the frequency subband is mute, and vice versa, determines that the serving cell is on on the frequency subband. Specifically, a counter is installed for each frequency subband, and its initial value is set to zero. Also, when different increments are given to different performance amplification intervals, and the second information indicating the different performance amplification intervals is received, the increment corresponding to the value of the counter is increased, and the first information indicating the different performance amplification intervals is changed. When transmitted, the increment corresponding to the value of the counter may be decreased. Then, the on / mute state of the serving cell on the frequency subband is determined depending on whether the counter value is larger than the predetermined threshold value. The scheduled threshold value can be set flexibly depending on design requirements, and is 0, for example. In the example shown in Table 1, for example, when a binary value “00” is transmitted or received, the counter value is kept unchanged, and when a binary value “01” is transmitted or received, the counter value is 2 Decrease / increase, if the binary value “10” is transmitted or received, decrease the counter value by 4; if transmit or receive the binary value “11”, decrease / increase the counter value by 6 May be. Then, the counter value is compared with a preset threshold value 0. When the counter value is greater than 0, it indicates that the performance amplification that the mute of the serving cell brings to the neighboring cell is larger than the performance amplification that the mute of the neighboring cell brings to the serving cell. Should. Conversely, if the value of the counter is less than 0, it indicates that the performance amplification that the mute of the serving cell brings to the neighboring cell is smaller than the performance amplification that the mute of the neighboring cell brings to the serving cell. The serving cell should be turned on.

  After determining the on / mute state on the plurality of frequency subbands of the serving cell, the same steps as steps S202 and S203 described with reference to FIG. 2 are performed, thereby realizing scheduling of cell users. May be. It will not be described here.

  Compared with the scheduling method according to the first embodiment of the present invention, the scheduling method according to the third embodiment of the present invention is configured to determine the information from neighboring cells when determining the on / mute state on each frequency subband of the serving cell. Therefore, the influence on the performance of the neighboring cell is also taken into consideration, so that it is prevented that the performance of the neighboring cell is significantly adversely affected. Further, compared with the scheduling method according to the second embodiment of the present invention, in the scheduling method according to the third embodiment of the present invention, the performance that the first information and the second information bring to the neighboring cell by muting the serving cell. In order to more accurately represent the performance amplification brought to the serving cell by amplification and mute of neighboring cells, the scheduling result obtained in this way comprehensively considers the performance of each centrally coordinated cell and is effective. Improve the performance of the entire cooperative group.

  Next, a scheduling device for a cell according to an embodiment of the present invention will be described with reference to FIG. The device can execute the scheduling method for the cell described above. As described above, a scheduling device is installed in each cell that cooperates intensively. For example, in the application scene shown in FIGS. 1A and 1B, scheduling devices are installed in the cells 1-3, respectively. The three scheduling devices are connected to each other through a backhaul circuit. These scheduling devices may be installed in the control unit shown in FIG. 1 as BBUs, or may be installed in each eNB shown in FIG. In FIG. 6, three scheduling devices for cells 1 to 3 are shown, and the structure and operation thereof are basically the same. Therefore, the scheduling device 600 for cell 1 will be described below as an example. I will do it.

  As illustrated in FIG. 6, the scheduling device 600 includes a pre-scheduling device 601, a communication device 602, and a scheduling device 603.

  The pre-scheduling apparatus 601 determines an on / mute state (that is, an on / mute pattern) on a plurality of frequency subbands of the serving cell (cell 1 in FIG. 6). The pre-scheduling apparatus 601 may be realized by various methods, and detailed description of the pre-scheduling apparatus 601 will be described later.

  The communication device 602 exchanges the on / mute state on the plurality of frequency subbands with the neighboring cells (cells 2 and 3 in FIG. 6) of the serving cell. For example, the communication device 602 communicates with a communication device (not shown) in an adjacent cell via a backhaul circuit to exchange the on / mute state.

  The scheduling apparatus 603 performs scheduling based on various CSIs fed back by users of the serving cell and on / mute states on the plurality of frequency subbands of neighboring cells. As described above, the various CSIs include CSIs corresponding to different on / mute states of the cell and the neighboring cell, respectively. FIG. 7 shows a specific structure of the scheduling device 603. As illustrated in FIG. 7, the scheduling apparatus 603 may include a selection unit 6031 and a scheduling unit 6032. The selection unit 6031 may select a CSI corresponding to the on / mute state of the adjacent cell from the plurality of CSIs for each frequency subband. The scheduling unit 6032 may perform scheduling based on the selected CSI. For example, the scheduling unit 6032 performs scheduling for the user assigned to the frequency subband based on the selected CSI, selects the MCS level of the user, and causes the user to transmit data using the MCS level. To do. The selection unit 6031 and the scheduling unit 6032 may perform the operation by the method described with reference to FIG. 2 described above, and detailed description thereof is omitted here for simplification.

  Next, the pre-scheduling apparatus 601 will be described in detail. As will be described later, the pre-scheduling apparatus 601 can be realized by various methods.

  FIG. 8 is a first exemplary structure of the pre-scheduling apparatus 601. As illustrated in FIG. 8, the pre-scheduling apparatus 601 includes a calculation unit 6011 and a determination unit 6012. The calculation unit 6011 may calculate the performance loss of the serving cell when the serving cell is muted on one or more of the frequency subbands. As described above, the calculation unit 6011 may calculate the performance loss of the serving cell when the serving cell is muted on each frequency subband, and the serving cell is muted simultaneously on two or more frequency subbands. Serving cell performance loss may be calculated. The determination unit 6012 determines an on / mute state on the one or more frequency subbands of the serving cell based on whether the performance loss exceeds a loss threshold. The calculation unit 6011 and the determination unit 6012 may execute their operations by the method described with reference to FIG. 3 described above, and detailed description thereof is omitted here to avoid duplication.

  FIG. 9 is a second exemplary structure of the pre-scheduling device 601. As shown in FIG. 9, the pre-scheduling apparatus 601 includes a pre-scheduling unit 6011 ', a communication unit 6012', and a determining unit 6013 '.

  The pre-scheduling unit 6011 'performs pre-scheduling for each frequency subband, and determines a user to be assigned to the frequency subband. In addition, the pre-scheduling unit 6011 'may determine whether or not the user assigned to each frequency subband is a neighboring user. The pre-scheduling unit 6011 'may execute pre-scheduling by the method described with reference to FIG. 4 and determine the neighboring users, and detailed description thereof will be omitted here.

  When the user assigned to the frequency subband is a peripheral user, the communication unit 6012 'transmits a mute request for requesting mute on the frequency subband of the cooperative cell to the cooperative cell of the peripheral user. Further, the communication unit 6012 ′ may further receive a mute request for requesting mute on the frequency subband of the cell from an adjacent cell. The communication unit 6012 'may transmit the mute request to the cooperative cell through the backhaul circuit and receive the mute request transmitted from the neighboring cell. Similarly, if the user is not a nearby user, the communication unit 6012 'may not perform the transmission operation.

  The determination unit 6013 ′ may determine the on / mute state of the serving cell on the frequency subband based on the number of mute requests transmitted and the number of mute requests received. For example, when the difference between the number of received mute requests and the number of mute requests transmitted is larger than a predetermined quantity threshold for any frequency subband, the determination unit 6013 ′ may determine whether the frequency subband on the serving cell is on that frequency subband. Mute may be confirmed. The determination unit 6013 ′ may determine the on / mute state of the cell by the method described with reference to FIG. 4 and will not be described here. The quantity threshold may be set by the above method.

  FIG. 10 shows a third exemplary structure of the pre-scheduling device 601. As illustrated in FIG. 10, the pre-scheduling apparatus 601 includes a pre-scheduling unit 6011 ″, a communication unit 6012 ″, and a determining unit 6013 ″.

  Similar to the pre-scheduling unit 6011 ′ illustrated in FIG. 9, the pre-scheduling unit 6011 ″ may perform pre-scheduling with respect to each frequency subband and determine a user to be allocated to the frequency subband. Further, the pro-scheduling unit 6011 ″ may further determine whether or not the user assigned to each frequency subband is a peripheral user.

  When the user assigned to the frequency subband is a neighboring user, the communication unit 6012 '' transmits the first information to the cooperative cell of the neighboring user, and as described above, the first information is received by the cooperative cell. Fig. 5 shows performance amplification that is brought to the serving cell when muted on the frequency resource. Also, the communication unit 6012 '' may receive second information from the neighboring cell, and the second information indicates the performance amplification that the serving cell brings to the neighboring cell when muted on the frequency subband. .

  Based on the first information and the second information, the determination unit 6013 ″ determines the on / mute state of the serving cell on the frequency subband. For example, for any frequency subband, when the performance amplification indicated by the first information is smaller than the performance amplification indicated by the second information, the determination unit 6013 '' mutes the frequency subband of the serving cell. Confirm. The determination unit 6013 '' may determine the on / mute state on the frequency subband of the serving cell by the method described with reference to FIG. 5, but detailed description is omitted here for the sake of simplicity. I will do it.

  Through the scheduling method and scheduling device for a cell according to the above embodiment of the present invention, scheduling can be performed in a fairly short time interval (for example, 1 ms), and channel state information fed back from the user when scheduling is performed. Since the channel state information can reflect the dynamic change of the radio environment, the scheduling result obtained by using the scheduling method and the scheduling device according to the embodiment of the present invention can cope with the change of the radio environment. This improves system performance.

  The scheduler may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both. Software modules include RAM (Random Access Memory), flash memory, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), hard disk, register, and hard disk. It may be installed in any type of storage medium such as a CD-ROM. The storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, the storage medium may be integrated in the processor. Further, the storage medium and the processor may be installed in a dedicated integrated circuit (ASIC). The ASIC may be installed in the control unit or the radio base station eNB. Moreover, the said storage medium and processor may be installed in the said control part or radio base station eNB as a discrete component.

  Although exemplary embodiments of the present invention have been described, those skilled in the art will recognize that various embodiments can be made to these exemplary embodiments without departing from the scope and spirit of the invention as defined by the claims and their equivalents. Obviously, changes in form and detail may be made.

Claims (14)

A scheduling method for a cell, comprising:
Determining an on / mute state on a plurality of frequency resources of the cell;
Exchanging on / mute states on the plurality of frequency resources with neighboring cells of the cell;
Scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell;
Have
Determining the on / mute state on multiple frequency resources of the cell comprises:
Calculating a performance loss of the cell when the cell is muted on one or more frequency resources in the plurality of frequency resources;
Determining an on / mute state on the one or more frequency resources of the cell based on whether the performance loss exceeds a loss threshold; and
How that have a. A scheduling method for a cell, comprising:
Determining an on / mute state on a plurality of frequency resources of the cell;
Exchanging on / mute states on the plurality of frequency resources with neighboring cells of the cell;
Scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell;
Have
Determining the on / mute state on multiple frequency resources of the cell comprises:
Pre-scheduling for each frequency resource and determining the users assigned to the frequency resource;
If the user assigned to the frequency resource is a neighboring user, transmitting a mute request to the cooperative cell so that the cooperative cell of the neighboring user is muted on the frequency resource;
Receiving a mute request from a neighboring cell so that the cell is muted on the frequency resource;
Determining an on / mute state on the frequency resource of the cell based on the number of mute claims transmitted and the number of mute claims received;
How that have a. 3. The mute on the frequency resource of the cell is determined when a difference between the number of received mute requests and the number of mute requests transmitted is larger than a quantity threshold for any frequency resource. the method of. A scheduling method for a cell, comprising:
Determining an on / mute state on a plurality of frequency resources of the cell;
Exchanging on / mute states on the plurality of frequency resources with neighboring cells of the cell;
Scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell;
Have
Determining the on / mute state on multiple frequency resources of the cell comprises:
Determining a user to be allocated to the frequency resource by performing pre-scheduling for each frequency resource;
If the user assigned to the frequency resource is a neighboring user, the first information indicating performance amplification to be provided to the cell when the neighboring user's cooperative cell is muted on the frequency resource is transmitted to the cooperative cell. Steps,
Receiving second information from a neighboring cell indicating performance amplification to the neighboring cell when the cell is muted on the frequency resource;
Determining an on / mute state on the frequency resource of the cell based on the first information and the second information;
How that have a. The method according to claim 4 , wherein, for any frequency resource, when the performance amplification indicated by the first information is smaller than the performance amplification indicated by the second information, mute on the frequency resource of the cell is determined. Various channel state information which the user has fed back of the cell A method according to any one of claims 1 to 5 having a corresponding channel state information to different on / mute state of the adjacent cell and the cell. Scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell,
Selecting channel state information corresponding to the on / mute state of the neighboring cell from the various channel state information for each frequency resource;
Scheduling based on the selected channel state information;
The method according to any one of claims 1 to 5 having a. A scheduling device for a cell,
A pre-scheduling device for determining an on / mute state on a plurality of frequency resources of the cell;
A communication device for exchanging on / mute states on the plurality of frequency resources of each of the adjacent cells of the cell;
A scheduling device that performs scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell;
Have
The pre-scheduling device includes:
A calculator that calculates a performance loss of the cell when the cell is muted on one or more frequency resources in the frequency resource;
A determination unit for determining an on / mute state on the one or more frequency resources of the cell based on whether the performance loss exceeds a loss threshold;
Lud devices that have a. A scheduling device for a cell,
A pre-scheduling device for determining an on / mute state on a plurality of frequency resources of the cell;
A communication device for exchanging on / mute states on the plurality of frequency resources of each of the adjacent cells of the cell;
A scheduling device that performs scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell;
Have
The pre-scheduling device includes:
Pre-scheduling for each frequency resource and determining a user to be allocated to the frequency resource;
If the user assigned to the frequency resource is a neighboring user, the mute request is sent to the cooperative cell so that the cooperative cell of the neighboring user is muted on the frequency resource, and the cell from the neighboring cell A communication unit that receives a mute request to mute on the frequency resource;
A determination unit for determining an on / mute state on the frequency resource of the cell based on the number of mute requests transmitted and the number of mute requests received;
Lud devices that have a. When the difference between the number of received mute requests and the number of transmitted mute requests is greater than a quantity threshold for any frequency resource, the determination unit determines mute on the frequency resource of the cell. Item 10. The device according to Item 9 . A scheduling device for a cell,
A pre-scheduling device for determining an on / mute state on a plurality of frequency resources of the cell;
A communication device for exchanging on / mute states on the plurality of frequency resources of each of the adjacent cells of the cell;
A scheduling device that performs scheduling based on various channel state information fed back by users of the cell and on / mute states on the plurality of frequency resources of the neighboring cell;
Have
The pre-scheduling device includes:
A pre-scheduling unit that determines a user to be allocated to the frequency resource by performing pre-scheduling for each frequency resource;
When the user assigned to the frequency resource is a neighboring user, the first information indicating performance amplification to be provided to the cell when the neighboring user's cooperative cell is muted on the frequency resource is transmitted to the cooperative cell. And a communication unit that receives second information from a neighboring cell indicating performance amplification that is provided to the neighboring cell when the cell is muted on the frequency resource;
A determination unit for determining an on / mute state on the frequency resource of the cell based on the first information and the second information;
Lud devices that have a. For any frequency resources, when the performance amplification indicated by the first information is smaller than the performance amplification indicated by the second information, in claim 11, wherein the determination unit is to determine the mute on the frequency resources of the cell The device described. The device according to any one of claims 8 to 12 , wherein various channel state information fed back by a user of the cell includes channel state information respectively corresponding to different on / mute states of the cell and the neighboring cell. The scheduling device includes:
For each frequency resource, a selection unit that selects channel state information corresponding to the on / mute state of the neighboring cell from the various channel state information;
A scheduling unit that performs scheduling based on the selected channel state information;
A device according to any one of claims 8 to 12 having a.

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