CN102740301B - Inter cell interference coordination (ICIC) method and apparatus thereof - Google Patents
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Abstract
The invention discloses an inter cell interference coordination (ICIC) method and an apparatus thereof. The method comprises the following steps: determining whether all the UE possess GBRs in a cell; if the GBRs are not possessed by all the UE in the cell, acquiring SIRs of all the UE in the cell and determining a Gini coefficient in the cell according to the SIRs of all the UE in the cell; when the Gini coefficient is greater than a preset first threshold, starting a interference coordination function of the cell. In the prior art, dynamic ICIC can not acquire adjacent cell information in time so as to adjust the cell and static interference coordination is only suitable for an occasion with an uniform load so that an interference coordination effect is not ideal. Through a technical scheme provided in the invention, the above problem can be solved and the each cell can achieve a good interference coordination effect under the condition that the load is nonuniform.
Description
Technical Field
The present invention relates to the field of communications, and in particular, to a method and an apparatus for coordinating inter-cell interference.
Background
The data rates provided by existing cellular mobile communication systems (e.g., 3G systems) vary greatly between the cell center and the cell edge, which not only affects the capacity of the entire system, but also causes the quality of service obtained by users at different locations to fluctuate greatly. Therefore, the new generation broadband wireless communication system currently under development has improved cell edge performance as one of the main requirements. Especially in the cell edge zone, the performance is greatly affected by the inter-cell interference. And because the physical layer technology itself has no inter-cell interference suppression mechanism, if the frequency reuse factor is 1, the inter-cell interference level is increased, and especially the performance of users located at the cell edge is greatly lost. To increase the data rate at the cell edge, the inter-cell interference must be effectively mitigated. Interference coordination is an effective way to effectively mitigate inter-cell interference.
Interference coordination is sometimes called interference avoidance, and its methods are many, but the basic principle is to set a certain limit on uplink and downlink resource management to coordinate actions of multiple cells and avoid generating serious inter-cell interference. This limitation may be a limitation on the resource scheduling or a limitation on the transmit power within a certain resource block. It can be said to improve the performance of cell edge users to a certain extent by sacrificing the performance of cell center users. According to the flexibility of resource allocation, the inter-cell interference coordination technology in a TD-HSPA (time division-High Speed Downlink Packet Access) system can be divided into static coordination and dynamic coordination.
The basic idea is to control inter-cell interference by managing radio resources, and is a multi-cell radio resource management scheme considering resource usage, load, and the like in a plurality of cells. Specifically, ICIC (Inter Cell interference coordination) limits the use of radio resources in each Cell in an Inter-Cell coordination manner, including limiting the use of time-frequency resources or limiting the transmission power of certain time-frequency resources, so as to ensure that the spectrum efficiency of edge users is improved as much as possible without reducing the system throughput.
The static interference coordination algorithm avoids the generation of strong interference among networks by staggering scheduling on time or space to form users with strong interference, mainly solves the problem that the strong interference among cells influences the performance of the users, and greatly improves the performance of edge users once the strong interference is controlled. The static Interference control algorithm design is divided into a TIC (Time Interference Coordination) algorithm and a SIC (Space Interference Coordination) algorithm, and users of adjacent cells are respectively scheduled in a staggered manner in Time and Space.
The static interference coordination algorithm is implemented in a way that scheduling is staggered from time and space in any situation, and when the performance of a central user of the whole network is good and the performance of the edge is poor and the load of the whole network is proper, the performance of static interference coordination is better. When the load of the whole network is uneven, so that some cell edge users are few, or the performance of the whole network is poor, negative effects are actually brought to the system. The performance of the dynamic interference coordination algorithm is better than that of static interference coordination because the interference characteristics of the adjacent cells are considered. However, in the TD-HSDPA system, the dynamic interference coordination algorithm needs to transfer information related to the neighboring cell from an Iub interface (interface between the radio network controller and the node B), and the delay of the Iub interface is too large, which cannot be implemented in the existing network.
Disclosure of Invention
The present invention is directed to a method and an apparatus for inter-cell interference coordination, so as to solve the above problems.
According to an aspect of the present invention, there is provided an inter-cell interference coordination method, including: judging whether all the UE in the cell have GBR; when not all UE in the cell has GBR, acquiring the signal to interference ratio SIR of all UE in the cell, and determining the Gini coefficient of the cell according to the SIR of all UE in the cell; and when the Gini coefficient is larger than a preset first threshold, opening the interference coordination function of the cell.
After determining whether all UEs in the cell have GBRs, the method further includes: when all the UE in the cell has GBR, judging whether the GBR unsatisfied rate of a central user in the cell is less than or equal to a preset second threshold or not; when the GBR unsatisfied rate of the center user is smaller than or equal to a preset second threshold, judging whether the GBR unsatisfied rate of the edge users in the cell is larger than a preset third threshold; and when the GBR unsatisfied rate of the edge user is larger than a preset third threshold, opening the interference coordination function of the cell.
Before determining whether all UEs in the cell have GBRs, the method further includes: and configuring time slot resources after the interference coordination function is opened for the cell according to a preset time slot allocation strategy.
After the cell switches on the interference coordination function, the method further comprises the following steps: and when a predetermined condition is met, the interference coordination function of the cell is closed, wherein the predetermined condition comprises at least one of the following conditions: the number of users in the cell is smaller than a preset fourth threshold; the number of edge users of the cell is 0; the GBR unsatisfied rate of the central users of the cell is greater than a preset second threshold; the guard timer of the cell times out.
The algorithm for determining the Gini coefficient of a cell according to the SIR of all UEs in the cell comprises:
wherein N is the number of all UE in the cell, and when Min is less than or equal to 0, pi=(i/N,(Siri-Min+1)/Sirtotal),pi,1=i/N,pi,2=(Siri-Min+1)/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,when Min > 0, pi=(i/N,Siri/SirTotal),pi,1=i/N,pi,2=Siri/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,
according to another aspect of the present invention, there is provided an inter-cell interference coordination apparatus, including: the system comprises a guarantee judging module, a data processing module and a data processing module, wherein the guarantee judging module is used for judging whether all User Equipment (UE) in a cell have a guaranteed bit rate GBR; a coefficient determining module, configured to obtain the SIR of all UEs in the cell when all UEs do not have GBR in the cell, and determine a Gini coefficient of the cell according to the SIR of all UEs in the cell; and the function starting module is used for starting the interference coordination function of the cell when the Gini coefficient is greater than a preset first threshold.
The above-mentioned inter-cell interference coordination apparatus further includes: the center judgment module is used for judging whether the GBR unsatisfied rate of the center user in the cell is less than or equal to a preset second threshold or not when all the UE in the cell has GBR; the edge judgment module is used for judging whether the GBR unsatisfied rate of edge users in the cell is greater than a preset third threshold or not when the GBR unsatisfied rate of the center users is less than or equal to the preset second threshold; the function starting module is further configured to start the interference coordination function of the cell when the GBR unsatisfied rate of the edge user is greater than a preset third threshold.
The above-mentioned inter-cell interference coordination apparatus further includes: and the time slot configuration module is used for configuring the time slot resources after the interference coordination function is opened for the cell according to a preset time slot allocation strategy.
The above-mentioned inter-cell interference coordination apparatus further includes: a function closing module, configured to close an interference coordination function of a cell when a predetermined condition is met after the interference coordination function is turned on by the cell, where the predetermined condition includes at least one of: the number of users in the cell is smaller than a preset fourth threshold; the number of edge users of the cell is 0; the GBR unsatisfied rate of the central users of the cell is greater than a preset second threshold; the guard timer of the cell times out.
The algorithm for determining the kini Gini coefficient of the cell by the coefficient determining module according to the SIR of all the UE in the cell comprises the following steps:
wherein N is the number of all UE in the cell, and when Min is less than or equal to 0, pi=(i/N,(Siri-Min+1)/SirTotal),pi,1=i/N,pi,2=(Siri-Min+1)/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,when Min > 0, pi=(i/N,Siri/SirTotal),pi,1=i/N,pi,2=Siri/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,
by the invention, Gini coefficients of the cell are calculated according to SIR (Signal to interference Ratio) of all UE (User Equipment) in the cell, and the variation condition of interference is represented by the Gini coefficients to decide to turn on or turn off the interference coordination function of the cell, thereby solving the problem that the interference coordination effect is not ideal because dynamic ICIC interference coordination cannot timely obtain adjacent cell information to adjust the cell and static interference coordination is only suitable for the occasion with uniform load in the prior art, and ensuring that each cell can obtain better interference coordination effect under the condition of non-uniform load.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
fig. 1 is a flow chart of an inter-cell interference coordination method according to an embodiment of the present invention;
fig. 2 is a flow chart of an inter-cell interference coordination method according to a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram of the soft time multiplexing involved in the TIC algorithm according to an example of the present invention;
FIG. 4 is a flow diagram of turning off an interference coordination function according to an example of the present invention;
fig. 5 is a block diagram of an inter-cell interference coordination apparatus according to an embodiment of the present invention;
fig. 6 is a block diagram of an inter-cell interference coordination apparatus according to a preferred embodiment of the present invention.
Detailed Description
The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
Fig. 1 is a flowchart of an inter-cell interference coordination method according to an embodiment of the present invention. As shown in the figure, the inter-cell interference coordination method according to the embodiment of the present invention includes:
step S102, judging whether all UE in the cell have GBR (Guaranteed bit rate);
step S104, when not all UE in the cell has GBR, obtaining SIR of all UE in the cell, and determining Gini coefficient of the cell according to SIR of all UE in the cell;
step S106, when the Gini coefficient is larger than a preset first threshold (marked as Thr)1) And when the interference coordination function of the cell is started.
In the prior art, dynamic ICIC interference coordination cannot obtain neighbor cell information in time due to too large Iub port delay so as to adjust the cell, while static interference coordination is only suitable for occasions with uniform load, and these defects can cause that the interference coordination effect is not ideal in practical application, thereby bringing negative effects to the system. The method comprehensively considers the uneven cell load and the change of cell user service, conditionally opens the interference coordination function, thereby improving the interference coordination effect to a great extent, and being a quasi-dynamic interference coordination method.
In the above method, it is first determined whether all UEs in the cell have GBR, because different determination results actually correspond to different processing methods. When not all UEs have GBR, it is necessary to further acquire the SIR of all UEs and finally determine the Gini coefficient of the cell according to the SIR. The Gini coefficient is applied here to represent the performance difference between all UEs in a cell, and when the Gini coefficient is larger, it indicates that the performance difference between UEs in the cell is larger, and then the interference coordination function needs to be opened to reduce the difference, and when the Gini coefficient is smaller, it indicates that the performance difference between UEs in the cell is smaller, and then it does not need to be opened. Therefore, a threshold (i.e., the first threshold) may be set as a basis for opening the interference coordination function, when the Gini coefficient is greater than the threshold, the interference coordination function is opened, and when the Gini coefficient is less than or equal to the threshold, the interference coordination function is not opened, and the process is directly ended. The value of the threshold can be set according to specific requirements, the value of the threshold is different for different systems, and the threshold can be optimized through simulation, so that an optimal value exists.
Preferably, as shown in fig. 2, after determining whether all UEs in the cell have GBRs, the method may further include:
step S212, when all the UEs in the cell have GBR, determining that the GBR unsatisfied rate (denoted as NSR) of the central users in the cellC) Whether the threshold is less than or equal to a preset second threshold (marked as Thr)2);
Step S214, when the GBR unsatisfied rate of the center user is less than or equal to the preset second threshold, the GBR unsatisfied rate (marked as NSR) of the edge user in the cell is judgededge) Whether it is greater than a preset third threshold (denoted as Thr)3);
And step S216, when the GBR unsatisfied rate of the edge user is larger than a preset third threshold, opening the interference coordination function of the cell.
When all UEs in a cell have GBR, its subsequent processing is distinct from that when not all UEs in the cell have GBR. When all UEs in a cell have GBRs, it needs to further determine whether the GBR unsatisfied rate of a central user is less than or equal to a preset second threshold, that is, whether the performance of the central user is good enough, because interference coordination improves the performance of cell edge users by sacrificing the performance of the cell central user to some extent, and it is meaningless to do interference coordination when the GBRs of the central user are not guaranteed. When the performance of the central user is good enough, it can be further determined whether the GBR unsatisfied rate of the edge user is greater than a preset third threshold, i.e., whether the performance of the edge user is poor enough, because obviously, it is meaningful to perform interference coordination only when the performance of the edge user is poor. When one of the above conditions is not satisfied, the interference coordination function does not need to be turned on, and the process may be ended. It should be noted that, for different systems, the values of the second threshold and the third threshold are also different, and the values of the two thresholds can also be optimized through simulation, so that an optimal value exists.
Here, it can be seen that the following processes are divided into two types according to the result of the GBR determination of all UEs in the cell, as shown in fig. 2, wherein steps S206 to S210 and S216 correspond to steps S102 to S106.
Preferably, as shown in fig. 2, before determining whether all UEs in the cell have GBRs, the method may further include:
step S202, configuring time slot resources, namely configuring the time slot resources after the interference coordination function is opened for the cell according to a preset time slot allocation strategy.
The above steps are mainly for the fact that a TIC algorithm is adopted after the cell interference coordination function is turned on, when the system is in an initial state, each base station configures time slot resources after the interference coordination function is turned on for each cell according to a preset time slot allocation strategy, and the time slot allocation strategy is only used when the cell interference coordination function is turned on. After the cell enters ICIC, each cell has a fixed special TTI, when the special TTI comes, edge users are scheduled preferentially, and the transmission power is increased. And the non-special TTI does not schedule the edge users and the central users, and reduces the transmitting power of the central users.
In general (see fig. 2), the above preferred embodiment may include the following steps:
1. when the system is in an initial state, each base station configures time slot resources after an interference coordination function is opened for each cell according to a preset time slot allocation strategy;
2. when all the UE in the cell have GBR guarantee, the step 3 is carried out, and when not all the UE in the cell have GBR guarantee, the step 4 is carried out;
3. when the GBR unsatisfied rate of the central user is larger than the second threshold, the interference coordination is not carried out, and when the GBR unsatisfied rate of the central user is smaller than or equal to the second threshold, the step 5 is carried out;
4. and calculating SIRs of all UE in the cell, and calculating the Gini coefficient of the cell by using the SIRs of all UE in the cell. Comparing the Gini coefficient with a first threshold, and opening the interference coordination function of the cell when the Gini coefficient is larger than the first threshold, otherwise not opening the interference coordination function of the cell;
5. and if the ratio of the GBR unsatisfied by the edge user is larger than a third threshold, opening the interference coordination function of the cell, otherwise, not opening the interference coordination function.
Preferably, after the cell turns on the interference coordination function, the method may further include:
and when a predetermined condition is met, turning off an interference coordination function of the cell, wherein the predetermined condition may include at least one of the following: the number of users in the cell is less than a preset fourth threshold (marked as Thr)4) (ii) a The number of edge users of the cell is 0; the GBR unsatisfied rate of the central users of the cell is greater than the preset second threshold; the guard timer of the cell times out.
In a specific implementation process, after the interference coordination function is turned on, when certain conditions are met, it is not necessary to continue interference coordination, for example, the number of users in a cell is smaller than a preset fourth threshold, that is, there are fewer users in the cell, and since there are fewer users, the performance of each user is naturally improved, so it is not necessary to continue interference coordination; the number of edge users in a cell is 0, and when no edge user exists in the cell, interference coordination is naturally not mentioned; the GBR unsatisfied rate of the central users of the cell is greater than the preset second threshold, and when the performance of the central users cannot be guaranteed, interference coordination is not meaningful; the protection timer of the cell is overtime, and when the cell has the protection timer, under the condition that the protection timer is overtime, the interference coordination is naturally stopped. It should be noted that the conditions for turning off the cell interference coordination function are not limited to the above 4 types, and may be extended according to specific situations.
Preferably, the algorithm for determining the Gini coefficient of the cell according to the SIR of all UEs in the cell includes:
n is the number of all UE in the cell, when Min is less than or equal to 0, pi=(i/N,(Siri-Min+1)/SirTotal),pi,1=i/N,pi,2=(Siri-Min+1)/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,when Min > 0, pi=(i/N,Siri/SirTotal),pi,1=i/N,pi,2=Siri/SitTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,
the algorithm can be completed in two steps:
step 1: let SIR of UE be Sir respectively1,Sir2,...,SirNMin ═ Min (Sir) is provided1,Sir2,...,SirN) If Min is less than or equal to 0, then there arepi=(i/N,(Sir1-Min+1)/SirTotal) If Min > 0, then there arepi=(i/N,Siri/SirTotal);
Step 2: in a square with a side length of 1, the following N points are drawn from small to large: p is a radical of1,p2,...,pNConnecting the N points and then connecting with the origin p0(0, 0) are linked; drawing a diagonal line between the left lower corner and the right upper corner of the square, wherein a curve formed by connecting the diagonal line and the N points forms a closed space with the area of STotal;Gini=STotal/(1/2), where 1/2 is the area of the lower triangle, Gini-2 × STotalThe maximum Keyny coefficient is 1, and the minimum Keyny coefficient is 0, and the specific calculation steps are as follows:
the value B calculated by the above formula is the area of the region under the calculation curve and surrounded by the X axis. Since the region is composed of a plurality of trapezoids, the summation symbol is internally provided with a formula of the area of the trapezoids.
Thus, Gini ═ 2 × STotal=2*(1/2-B)=1-2B。
The above preferred embodiments are described in detail below with reference to examples, the entire example comprising the steps of:
and step 1, initializing. The initialization is mainly carried out by each base station according to a preset time slot allocation strategy, configuring time slot resources after the interference coordination function is opened for each cell, wherein the time slot allocation strategy mainly refers to time slot allocation related in a TIC algorithm, and the time slot allocation strategy is only used when the interference coordination function of the cell is opened.
The design idea of the TIC algorithm is to set a section of special TTI (Transmission Time interval) for each cell, the special TTIs of adjacent cells are configured in a staggered manner, the priority of edge users is increased at each NodeB (node B) side in the special TTI, so that the purpose of scheduling edge users in a staggered manner in adjacent cells is achieved, and the Transmission power of the scheduling users is reduced at this moment in the adjacent cells, so as to reduce the interference to the edge users of the current cell.
The gist of this algorithm is to configure each cell with a special time period, i.e. soft time multiplexing. A simple configuration is 1: 3 multiplexing, shown in FIG. 4, TsFor a particular TTI length, 100 subframe lengths are configured by default. The three cells controlled by each base station are numbered 1, 2 and 3 in sequence as special scheduling time interval numbers. As shown in fig. 4, special TTI segments of different shadings are allocated to the cell corresponding to the shadings.
Step 2, to make edge and center user decision (refer to step S204 in fig. 2), the decision is based on SNPL (Serving and Neighbor Cell Path Loss) of the UE. When the SNPL is less than a threshold, it is considered an edge user, otherwise it is considered a center user. The recommended value of the threshold is 2 dB. Of course, this step is not required in the case where the edge users and the center user have already been identified.
And 3, judging whether all the UE in the cell have GBR, if so, executing the step 4, and if not, executing the step 6.
And 4, judging the performance of the cell center user when the service transmitted by the cell UE has GBR guarantee, and improving the performance of the cell edge user by sacrificing the performance of the cell center user to a certain extent in interference coordination, wherein the interference coordination is meaningless when the GBR of the center user cannot be guaranteed. Only the rate that the GBR of the central user does not meet is less than or equal to one threshold (Thr)2) And step 5 is executed, otherwise, the cell does not open the interference coordination function.
Step 5, judging the performance of the edge user, when the GBR of the edge user does not satisfy more than a threshold (Thr)3) Then, the interference coordination function of the cell is turned on.
Step 6, when the cell isWhen the service transmitted by the UE has no GBR guarantee, calculating the Gini coefficient to judge the performance difference of all UE in the cell, and when the performance difference of all UE is larger than a threshold (Thr)1) And if so, the cell opens the interference coordination function, otherwise, the cell does not open the interference coordination function.
The threshold (Thr) referred to herein1、Thr2、Thr3) The specific value of the value needs to be optimized through simulation, and an optimal value exists.
ICIC exit mechanism (i.e., the flow of turning off the interference coordination function) as shown in fig. 4, there are several situations in which ICIC may be exited. When the number of users in the cell is less than a threshold (Thr)4) And when the current cell has no edge UE, exiting the ICIC. Since ICIC improves the performance of the edge users by sacrificing the performance of the center users, the performance of the center users is reduced more after the ICIC is opened, and the GBR unsatisfied rate of the center users is larger than a threshold (Thr)2) Then exit ICIC must be considered, in reference to step S404. In order to avoid ping-pong handover of cells before ICIC is turned on and ICIC exits, a protection timer is set for each cell, referring to step 406, when a cell is in a non-ICIC state, the timer is cleared, and when the cell is in an ICIC state, the timer starts to operate. After performing step 404, if the guard timer times out, the cell exits ICIC, otherwise it does not exit.
Also, the threshold (Thr) mentioned here2、Thr4) The specific value of the time limit of the protection timer needs to be optimized through simulation, and an optimal value exists.
Simulation verification proves that through the process, under the condition that the load of each cell is uniform, the scheme is equivalent to the static ICIC, and under the condition that the load of each cell is non-uniform, the scheme has a gain of 10% -25% compared with the static ICIC scheme.
Fig. 5 is a block diagram of an inter-cell interference coordination apparatus according to an embodiment of the present invention. As shown in fig. 5, an inter-cell interference coordination apparatus according to an embodiment of the present invention includes:
a guarantee judging module 504, configured to judge whether all UEs in a cell have GBRs;
a coefficient determining module 506, connected to the guarantee judging module 504, and configured to obtain SIR of all UEs in the cell when all UEs in the cell do not have GBR, and determine a kini Gini coefficient of the cell according to the SIR of all UEs in the cell;
a function starting module 508, connected to the coefficient determining module 506, for starting the interference coordination function of the cell when the Gini coefficient is greater than the preset first threshold.
The device applies a quasi-dynamic interference coordination scheme, comprehensively considers the cell load unevenness and the cell user service change, conditionally opens the interference coordination function, and improves the interference coordination effect to a great extent.
In the above apparatus, the guarantee judgment module 504 is mainly used to judge whether all UEs in the cell have GBR, because different judgment results actually correspond to different processing methods. When not all UEs have GBR, the coefficient determining module 506 needs to further obtain SIR of all UEs and finally determine Gini coefficient of the cell according to the SIR. The Gini coefficient is applied here to represent the performance difference between all UEs in a cell, and when the Gini coefficient is larger, it indicates that the performance difference between UEs in the cell is larger, and then the interference coordination function needs to be opened to reduce the difference, and when the Gini coefficient is smaller, it indicates that the performance difference between UEs in the cell is smaller, and then it does not need to be opened. Therefore, a threshold (i.e., the first threshold) may be set as a basis for opening the interference coordination function, when the Gini coefficient is greater than the threshold, the function opening module 508 opens the interference coordination function, and when the Gini coefficient is less than or equal to the threshold, the flow is directly ended without opening the interference coordination function. The value of the threshold can be set according to specific requirements, and for different systems, the value of the threshold can be optimized through simulation, and an optimal value exists.
Preferably, as shown in fig. 6, the inter-cell interference coordination apparatus according to the embodiment of the present invention may further include:
a center determining module 510, connected to the guarantee determining module 504, configured to determine whether a GBR unsatisfied rate of a center user in the cell is less than or equal to a preset second threshold when all UEs in the cell have GBRs;
and an edge determining module 512, connected to the center determining module 510, configured to determine whether the GBR unsatisfied rate of the edge user in the cell is greater than a preset third threshold when the GBR unsatisfied rate of the center user is less than or equal to the preset second threshold.
The function starting module 508 is also connected to the edge determining module 512, and is further configured to start the interference coordination function of the cell when the GBR unsatisfied rate of the edge user is greater than a preset third threshold.
When all UEs in a cell have GBR, its subsequent processing is distinct from that when not all UEs in the cell have GBR. When all UEs in the cell have GBRs, the central determining module 510 needs to further determine whether the GBR unsatisfied rate of the central user is less than or equal to a preset second threshold, i.e., determine whether the performance of the central user is good enough, because interference coordination improves the performance of the cell edge users by sacrificing the performance of the cell central user to some extent, and it is meaningless to perform interference coordination when the GBRs of the central user are not guaranteed. When the performance of the central user is good enough, the edge determining module 512 may further determine whether the GBR unsatisfied rate of the edge user is greater than a preset third threshold, that is, whether the performance of the edge user is poor enough, because obviously, it is meaningful to perform interference coordination only when the performance of the edge user is poor. When one of the above conditions is not satisfied, it is not necessary to turn on the interference coordination function. It should be noted that, for different systems, the values of the second threshold and the third threshold are different, and the values of the two thresholds can also be optimized through simulation, and there is an optimal value.
Preferably, as shown in fig. 6, the inter-cell interference coordination apparatus according to the embodiment of the present invention may further include:
the time slot configuration module 502 is connected to the guarantee judgment module 504, and is configured to configure, according to a preset time slot allocation policy, a time slot resource after the interference coordination function is turned on for the cell.
The time slot configuration module 502 is mainly designed for a device that will adopt TIC algorithm after the cell opens the interference coordination function, and when the system is in an initial state, the time slot configuration module 502 will configure the time slot resources after the interference coordination function opens for each cell according to the preset time slot allocation strategy, which is only used when the cell interference coordination function opens. After the cell enters ICIC, each cell has a fixed special TTI, when the special TTI comes, edge users are scheduled preferentially, and the transmission power is increased. And the non-special TTI does not schedule the edge users and the central users, and reduces the transmitting power of the central users.
Preferably, as shown in fig. 6, the inter-cell interference coordination apparatus according to the embodiment of the present invention may further include:
a function closing module 514, connected to the function opening module 508, configured to close the interference coordination function of the cell when a predetermined condition is met after the interference coordination function is turned on by the cell, where the predetermined condition may include at least one of: the number of users in the cell is smaller than a preset fourth threshold; the number of edge users of the cell is 0; the GBR unsatisfied rate of the central users of the cell is greater than the preset second threshold; the guard timer of the cell times out.
In a specific implementation process, after the interference coordination function is turned on, when certain conditions are met, it is not necessary to continue interference coordination, and the function closing module 514 closes the interference coordination function, for example, the number of users in a cell is smaller than a preset fourth threshold, that is, there are fewer users in the cell, and since there are fewer users, the performance of each user is naturally improved, so it is not necessary to continue interference coordination; the number of edge users in a cell is 0, and when no edge user exists in the cell, interference coordination is naturally not mentioned; the GBR unsatisfied rate of the central users of the cell is greater than the preset second threshold, and when the performance of the central users cannot be guaranteed, interference coordination is not meaningful; the protection timer of the cell is overtime, and when the cell has the protection timer, under the condition that the protection timer is overtime, the interference coordination is naturally stopped. It should be noted that the conditions for turning off the interference coordination function of the cell are not limited to the above 4 types, and may be extended according to specific situations.
Preferably, the algorithm for determining the Gini coefficient of the cell by the coefficient determining module 506 according to the SIR of all UEs in the cell includes:
n is the number of all UE in the cell, when Min is less than or equal to 0, pi=(i/N,(Siri-Min+1)/SirTotal),pi,1=i/N,pi,2=(Siri-Min+1)/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,when Min > 0, pi=(i/N,Siri/SirTotal),pi,1=i/N,pi,2=Siri/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNThe SIR values for all UEs in the cell,
the process of the above algorithm performed by the coefficient determining module 506 is described in detail above, and is not described here again.
From the above description, it can be seen that the technical solution provided by the present invention is to measure some key parameters of the cell, characterize the variation situation of interference by these parameters, and when the performance of the edge user is deteriorated, turn on the interference coordination function of the cell, and when the interference environment of the cell becomes better, turn off the interference coordination function of the cell, thereby providing an interference coordination technology that can comprehensively consider the variation situation of cell load and cell user service.
It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An inter-cell interference coordination method, comprising:
judging whether all User Equipment (UE) in a cell have a Guaranteed Bit Rate (GBR);
when not all the UE in the cell have GBR, acquiring the signal to interference ratio (SIR) of all the UE in the cell, and determining a Gini coefficient of the cell according to the SIR of all the UE in the cell;
and when the Gini coefficient is larger than a preset first threshold, opening the interference coordination function of the cell.
2. The method of claim 1, wherein after determining whether all UEs in the cell have GBRs, further comprising:
when all the UE in the cell has GBR, judging whether the GBR unsatisfied rate of a central user in the cell is less than or equal to a preset second threshold or not;
when the GBR unsatisfied rate of the center user is smaller than or equal to the preset second threshold, judging whether the GBR unsatisfied rate of the edge users in the cell is larger than a preset third threshold or not;
and when the GBR unsatisfied rate of the edge user is greater than the preset third threshold, opening the interference coordination function of the cell.
3. The method of claim 2, further comprising, before determining whether all UEs in the cell have GBRs:
and configuring time slot resources after an interference coordination function is opened for the cell according to a preset time slot allocation strategy.
4. The method of claim 3, further comprising, after the cell turns on an interference coordination function:
turning off an interference coordination function of the cell when a predetermined condition is met, wherein the predetermined condition includes at least one of:
the number of users in the cell is smaller than a preset fourth threshold;
the number of edge users of the cell is 0;
the GBR unsatisfied rate of the central users of the cell is greater than the preset second threshold;
the guard timer of the cell times out.
5. The method according to any of claims 1-4, wherein the algorithm for determining the Gini coefficients of the cell based on the SIRs of all UEs in the cell comprises:
n is the number of all UE in the cell, when Min is less than or equal to 0, pi=(i/N,(Siri-Min+1)/Sirtotal),pi,1=i/N,pi,2=(Siri-Min+1)/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNFor the SIR values of all UEs in the cell,when Min > 0, pi=(i/N,Siri/SirTotal),pi,1=i/N,pi,2=Siri/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir2,Sir2,...,SirNFor the SIR values of all UEs in the cell,
6. an apparatus for coordinating inter-cell interference, comprising:
the system comprises a guarantee judging module, a data processing module and a data processing module, wherein the guarantee judging module is used for judging whether all User Equipment (UE) in a cell have a guaranteed bit rate GBR;
a coefficient determining module, configured to obtain signal-to-interference ratios, SIRs, of all UEs in the cell when all the UEs in the cell do not have GBRs, and determine a Gini coefficient of the cell according to the SIRs of all the UEs in the cell;
and the function starting module is used for starting the interference coordination function of the cell when the Gini coefficient is greater than a preset first threshold.
7. The apparatus of claim 6, further comprising:
the center judgment module is used for judging whether the GBR unsatisfied rate of the center user in the cell is less than or equal to a preset second threshold or not when all the UE in the cell has GBR;
the edge judgment module is used for judging whether the GBR unsatisfied rate of edge users in the cell is greater than a preset third threshold or not when the GBR unsatisfied rate of the center user is less than or equal to the preset second threshold;
the function starting module is further configured to, when the GBR unsatisfied rate of the edge user is greater than the preset third threshold, start the interference coordination function of the cell.
8. The apparatus of claim 7, further comprising:
and the time slot configuration module is used for configuring the time slot resources after the interference coordination function is opened for the cell according to a preset time slot allocation strategy.
9. The apparatus of claim 8, further comprising:
a function shutdown module, configured to shut down an interference coordination function of the cell when a predetermined condition is met after the interference coordination function is turned on by the cell, where the predetermined condition includes at least one of:
the number of users in the cell is smaller than a preset fourth threshold;
the number of edge users of the cell is 0;
the GBR unsatisfied rate of the central users of the cell is greater than the preset second threshold;
the guard timer of the cell times out.
10. The apparatus of any of claims 6-9, wherein the algorithm for determining the Gini coefficient of the cell according to the SIR of all UEs in the cell by the coefficient determining module comprises:
n is the number of all UE in the cell, when Min is less than or equal to 0, pi=(i/N,(Siri-Min+1)/SirTotal),pi-1=i/N,pi,2=(Siri-Min+1)/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNFor the SIR values of all UEs in the cell,when Min > 0, pi=(i/N,Siri/sirTotal),pi,1=i/N,pi,2=Siri/SirTotalWherein Min ═ Min (Sir)1,Sir2,...,SirN),Sir1,Sir2,...,SirNFor the SIR values of all UEs in the cell,
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