WO2011113192A1 - Distributed resource allocation method and device for reducing intercell downlink interference - Google Patents

Abstract

A simple distributed dynamic resource multiplexing form is disclosed. The distributed dynamic resource multiplexing form is more capable of adapting to the changeable network environment and promotes the utilization of a frequency spectrum as compared with a static software fractional frequency reuse (SFFR). The technical scheme has a low complexity and a very limited signaling overhead without generating a significant delay. Because each base station no longer makes the blind pursuit of maximizing the performance of the cell when allocating resources, but considers the impact on neighbor cells due to the behavior of allocating resources in the cell, so the technical scheme can more effectively reduce the intercell interference. In addition, comparing with the multiple sector gradient (MGR) algorithm, the technical scheme requires less amount of channel quality indication (CQI) information to be exchanged between base stations. With necessary information exchanges between cells, the technical scheme can bring better system performance than the sector autonomy (SA) algorithm without exchanges between cells.

Description

 Used to reduce the interval downlink interference

 Distributed resource allocation method and device

 The present invention relates to interference mitigation in wireless communication networks, and more particularly to resource allocation methods and apparatus for mitigating downlink channel interference between base stations. Background technique

 In an OFDMA or SC-OFDM based wireless communication network, in order to reduce the interference between regions, the industry has tried various solutions, including:

 Soft Fractional Frequency Multiplexing (SFFR), TSG-RAN WG1 #41, R1-050507, Huawei, "Soft Frequency Reuse Scheme for UTRAN LTE," Athens, Greece, May 2005; TSG-RAN WG1 #42, Rl-050841, Huawei, "Further Analysis of Soft Frequency Reuse Scheme," London, UK, September 2005.

 SFFR divides the available resource sets, such as spectrum, into multiple subsets. The available frequencies in the cell are available to mobile terminals located near the cell center, but for mobile terminals located at the cell edge, all that can be used is Some frequency subsets. In each cell, the frequencies respectively used for the mobile terminals allocated to the cell edge are orthogonal to each other, so that inter-cell interference can be avoided. A typical application of SFFR is to allocate smaller transmit power to mobile terminals near the cell center and allocate larger transmit power to the mobile terminals at the edge of the cell, that is, the downlink transmit power allocation of the base station itself.

There are some problems with SFFR, including: Since the frequencies allocated by the base stations in adjacent or similar cells to the mobile terminals at the cell edge are not overlapping, although this orthogonal relationship achieves effective inter-cell interference suppression, Significantly reduce the efficiency of spectrum usage. In addition, although channel conditions and the like are time-varying, the frequency subset allocation method between several adjacent cells is static and does not change with channel conditions. Furthermore, the frequency and power allocation parameters of the mobile terminal at the cell center and the cell edge The choice is in an empirical way, which makes SFFR unsatisfactory in many scenarios.

 Resource allocation based on throughput boundary effect (TMU), G. Li and H. Liu, "Downlink Radio Resource Allocation for Multi-Cell OFDMA System," IEEE Transactions on Wireless Communications, pp. 3451-3459, December 2006.

 The TMU-based resource allocation solution is designed to maximize the overall throughput of the system through resource allocation. Specifically, the radio network controller (RNC) estimates the throughput of each mobile terminal in the centralized system in a centralized manner, thereby selecting a mobile terminal capable of maximizing system throughput.

 Existing TMU-based resource allocation schemes are not perfect. For example, because of the centralized scheduling and resource allocation of multiple cells under its jurisdiction through an RNC, this will require major changes to the existing network architecture. In addition, even if it costs more money, it will provide powerful RNC. The processor, which still becomes the bottleneck of the entire system and brings a large delay. In addition, this approach brings significant signaling overhead to the air interface between the base station and the mobile terminal. Furthermore, since an equal power distribution method is employed in the spectrum, the frequency gain cannot be maximized. Finally, existing TMU-based resource allocation methods are difficult to achieve optimal solutions due to their heuristic and greedy characteristics.

 Multi-sector gradient (MGR) and sector autonomous (SA) algorithms, A. Stolyar and H. Viswanathan, "Self-organizing Dynamic Fractional Frequency Reuse for Best-effort Traffic through Distributed Inter-cell Coordination," IEEE INFOCOM, pp. 1287-1295, April 2009; A. Stolyar and H. Viswanathan, "Method of Dynamic Resource Allocations in Wireless Systems," US Patent Application No. 20090003266.

 Both the MGR and SA algorithms pursue local maximization of the overall network effect by adjusting the transmit power of the base stations on different sub-bands, which are dynamic inter-cell interference coordination (ICIC) schemes.

The MGR and SA algorithms perform dynamic resource allocation adapted to the wireless environment of the neighboring cell. The wireless environment of the neighboring cell here includes a time-varying cell layout, a distribution of the mobile terminal, and a traffic load. Meanwhile, when performing dynamic resource allocation, the base station of one cell is independent of the frequency allocation of the neighboring cell. Therefore, in order to achieve power allocation, the cell must perform virtual scheduling or shadow scheduling for each frequency band, and virtual scheduling or shadow scheduling brings a considerable amount of computation to the base station, which in turn leads to A large delay. Summary of the invention

 Based on the above knowledge of the prior art, it is desirable to provide a distributed solution in the present application, which has limited signaling overhead and low implementation complexity.

 According to a specific embodiment of the present invention, a distributed resource allocation method for reducing downlink channel interference in a base station in a base station is provided, which includes the following steps: an obtaining step, wherein the base station obtains at least one other base station Interference strength indication information, where the interference strength indication information sent by each other base station indicates information about the interference strength that the other base station is located on at least one frequency band; a determining step, where Determining, by the base station, an association relationship between the interference strength indication information sent by the at least one other base station and the downlink transmission power allocation of the base station on the at least one frequency band; and an allocation step, wherein the base station is determined according to the determined And the associated relationship and the interference strength indication information sent by the at least one other base station, and the downlink transmit power of the local base station is allocated on the at least one frequency band.

 Further, the determining step determines the association relationship according to one of the following items: a. the downlink transmit power allocation of the base station on the at least one frequency band is such that the throughput achieved in the cell where the base station is located is The sum of the throughput drops in the cell where the at least one other base station is located is larger; b. the base station is sensitive to each frequency band from the base station in the cell where the at least one other base station is located A smaller downlink transmit power is allocated or not allocated, and a larger downlink transmit power is allocated on each frequency band in which the cell in which the other base station is located is less sensitive to interference from the base station.

Further, the foregoing method further includes the following steps, so that the base station can help Its other base stations perform the same distributed resource allocation:

 a scheduling step, wherein the base station selects, according to a single cell scheduling method, each mobile terminal that is separately served on the at least one frequency band in each scheduling period; and an acquiring step, where the base station acquires a cell corresponding to the base station Corresponding interference strength indication information, which indicates the interference strength that the base station bears on the at least one frequency band; and a sending step, where the base station sends the acquired interference strength indication information corresponding to the cell where the base station is located to a corresponding one of the at least one other base stations.

 According to another embodiment of the present invention, there is provided a distributed resource allocation apparatus for reducing downlink channel interference in a base station, comprising: an obtaining apparatus, configured to obtain interference generated by at least one other base station Intensity indication information, wherein the interference strength indication information sent by each other base station indicates information about the interference strength that the other base station is located on at least one frequency band; and determining means for determining the at least one other Correlation between the interference strength indication information sent by the base station and the downlink transmission power allocation of the base station on the at least one frequency band; a distribution apparatus, configured to send, according to the determined association relationship, the at least one other base station The incoming interference strength indication information allocates downlink transmission power of the base station on the at least one frequency band.

 Further, the determining device determines the association relationship according to one of the following items: a. the downlink transmit power allocation of the base station on the at least one frequency band is such that the throughput achieved in the cell where the base station is located is The sum of the throughput drops in the cell where the at least one other base station is located is larger; b. the base station is sensitive to each frequency band from the base station in the cell where the at least one other base station is located A smaller downlink transmit power is allocated or not allocated, and a larger downlink transmit power is allocated on each frequency band in which the cell in which the other base station is located is less sensitive to interference from the base station.

Further, the foregoing distributed resource allocation apparatus further includes the following sub-devices to help other base stations perform the same distributed resource allocation: a scheduling apparatus, where the base station selects based on a single cell scheduling method in each scheduling period. Each mobile terminal serving separately on the at least one frequency band; acquiring means for acquiring with the base station Interference strength indication information corresponding to the cell, indicating the interference strength of the cell where the base station is located in the at least one frequency band; the sending device, configured to: obtain the obtained interference strength indication information corresponding to the cell where the base station is located And sent to a corresponding one of the at least one other base station.

 According to still another embodiment of the present invention, a base station is provided, comprising the above-described distributed control apparatus for reducing downlink channel interference in a reduced interval.

 Advantageously, the solution of various embodiments of the present invention may be applied to each base station, rather than only to a particular base station, such that each base station considers its resource allocation, in particular power allocation, for neighboring cells. The impact, or a combination of the benefits of its power allocation, such as the throughput achieved and thus the impact on neighboring cells, to find the optimal power allocation result, and then allocate.

 The invention provides a simple distributed dynamic resource reuse form, and a static

Compared with SFFR, it is more adaptable to the changing network environment, and the utilization rate of the frequency is greatly improved. Moreover, the solution in the present invention is low in complexity, and the signaling overhead is very limited, and no significant delay is generated. Importantly, since each base station does not blindly pursue the performance maximization of the present cell when performing resource allocation, and considers the influence of the resource allocation behavior of the own cell on the neighboring cell, it can effectively reduce the interval. interference. In addition, the present invention requires less channel quality indicator (CQI) information to be exchanged between base stations than the MGR algorithm, and does not require complex virtual (shadow) scheduling for each frequency band, and at the same time, the present invention borrows a cell. The necessary information interaction between the two can provide better system performance than the SA algorithm without inter-cell interaction. DRAWINGS

 Other features and advantages of the present invention will become more apparent and apparent from the description of the appended claims. 1 is a schematic diagram of a network structure according to an embodiment of the present invention; FIG. 2 to FIG. 3 are diagrams showing downlink channel interference for reducing a section in a base station according to an embodiment of the present invention. Flow chart of a distributed resource allocation method;

Figure 4 illustrates a subtraction in a base station in accordance with an embodiment of the present invention. A block diagram of a distributed resource allocation device for downlink channel interference in a small interval.

 In the drawings, the same or similar reference numerals indicate the same or similar technical features. detailed description

 Non-limiting embodiments of the invention are described below with reference to the drawings. Referring first to Figure 1, there is shown a typical application scenario of the present invention, with base stations 2, 3 located at the center of cells 0, 1, respectively, and mobile terminals 4 and 5 located at the edges of the two cells, respectively. For more specific purposes, the downlink channels between each base station and the mobile terminal are composed of respective reference numerals of the corresponding base station and the mobile terminal, that is, the downlink channel 24 between the base station 2 and the mobile terminal 4, the base station 2 and the mobile The downlink channel 25 between the terminals 5, the downlink channel 34 between the base station 3 and the mobile terminal 4, and the downlink channel 35 between the base station 3 and the mobile terminal 5. In addition, the backhaul link between the base stations is omitted for simplicity in the figure. For similar purposes, only two adjacent cells and their network elements are shown in the figure. It is understood by the person that the present invention is fully applicable to the case of reducing interference between two or more cells.

 Thus, if the base station 2 selects the mobile terminal 4, the base station 3 selects the mobile terminal 5, and the frequency bands used by the two are the same, and the channel 25 and the channel 34 cause mutual interference of the cells 0, 1 in this frequency band.

 In order to avoid this problem, according to a specific embodiment of the present invention, a distributed resource allocation method for reducing downlink channel interference in a base station in a base station is provided, and the overall process is as shown in FIG. The base station 2 shown in FIG. 1 is an example. The method includes the following steps:

 Obtaining step S21, wherein the base station 2 obtains interference strength indication information sent by at least one other base station, where the interference strength indication information sent by each other base station indicates that the cell where the other base station is located is subjected to at least one frequency band. Information about the intensity of the interference.

A determining step S22, wherein the base station 2 determines an association relationship between the interference strength indication information sent by the at least one other base station and the downlink transmission power allocation of the base station 2 on the at least one frequency band. An allocation step S23, wherein the base station 2 allocates the downlink transmit power of the base station on the at least one frequency band according to the determined association relationship and the interference strength indication information sent by the at least one other base station.

 To facilitate understanding, some of the concepts involved are explained as follows:

 Inter-cell interference: Referring to FIG. 1, for the mobile terminal 5, the downlink signal on the channel 25 should be regarded as interference, which is referred to herein as interference generated by the cell 0 to the cell 1, and likewise, for the mobile terminal 4, the channel The downlink signal on 34 is also considered as interference, that is, the interference generated by cell 1 to cell 0. Of course, the present invention does not preclude interference between non-adjacent cells, and does not exclude the application of its solution to this situation.

 Today's distributed scheduling, distributed resource allocation: In the prior art, in the existing TMU-based resource allocation solution, centralized scheduling and resource allocation are performed by RNCs located upstream of multiple base stations, that is, Regardless of whether the base station selects the mobile terminal and then allocates resources for the selected mobile terminal, the decision is based on the RNC, which is centralized scheduling and resource allocation. Correspondingly, in accordance with at least one embodiment of the present invention, such mobile terminal selection and subsequent resource allocation are both decentralized to respective base stations, referred to as distributed scheduling and distributed resource allocation.

 The information about the interference strength: taking the downlink channel interference caused by the base station 2 to the mobile terminal 5 as an example, in the embodiment of the present invention, the interference strength may be received by the interfered party, for example, the mobile terminal 4 from the interference source (interference) For example, the strength of the downlink signal of the base station 3 is represented by RSSI. Similarly, the strength of the interference may also be represented by other physical quantities, which may not be equal to the interference strength, but still indicate the interference strength or Representative. In this context, it will be possible to directly equate to the interference strength and those physical quantities that can characterize the interference strength, collectively referred to as the correlation information of the interference strength.

At least one other base station: In the embodiment of the present invention, the downlink power allocation of a base station needs to consider the impact on the adjacent or neighboring cells. For this reason, the base station needs the base stations in the cells to provide some information. for reference. For each base station, it needs to be constructed by at least one base station. The set can be pre-configured and statically maintained, or can be changed according to special changes in the network, such as cell re-segmentation or base station changes. For example, as shown in FIG. 1, for the base station 1, at least one base station corresponding thereto may include only the base station 3, and may further include base stations in other cells not shown in the figure. The above description is equally applicable to the base station 3 and base stations not shown. Preferably, a plurality of base stations with relatively obvious mutual interference are mutually other base stations. Wherein, if a total number of frequency bands in which cell 0 and cell 1 are multiplexed, that is, the total number of at least one frequency band mentioned herein, is represented by a positive integer J, j=l, . . . , j represents a specific frequency band, according to the present invention. In a specific embodiment, for any one of the at least one frequency band j, the interference strength indication information sent by any other base station, such as the base station 3, includes the following information: the mobile terminal selected by the base station 3 for the frequency band j, such as a mobile terminal a gain of a downlink channel between the base station 2 and the base station 2, which is determined based on the strength of the downlink signal received by the mobile station 5 selected by the base station 3 from the base station 2; the cell in which the base station 3 is located is within a time period The sum of the interference noise received in the frequency band j, without loss of generality, may include a plurality of scheduling periods in the past, and one scheduling period may be one or more transmission time intervals (TTIs).

 Specifically, as commonly used in the prior art, the base station 2 broadcasts pilot signals on a common channel, and each mobile terminal under the jurisdiction of the other base station includes the mobile terminal 5 to determine the reception quality of the pilot signal, for example, The mobile terminal, as exemplified by the RSSI, reports the reception quality of the pilot signal to its home base station, such as the base station 3, and the home base station calculates the downlink between the base station 2 and the corresponding mobile terminal according to the reception quality. The gain of the channel is provided to the base station 2. Optionally, after proper configuration, the mobile terminal can calculate the above-mentioned gain by itself and report it to the home base station.

As can be seen from the above description, a base station 2 that may cause interference, in order to perform appropriate power allocation, requires reference information from other base stations in accordance with at least one embodiment of the present invention. In view of the fact that the base station 2 may not only cause interference to mobile terminals in other cells, the base station 2 and its mobile terminal, such as the mobile terminal 4, may also be interfered by downlink signals sent by other base stations. For this reason, the base station 2 is as shown in FIG. The various steps to provide the required information to other base stations. Those skilled in the art understand that other base stations also provide the required interference strength indication information for the base station 2 through the flow shown in FIG. Those skilled in the art should also understand that the flow shown in FIG. 3 is relatively independent of the flow shown in FIG. 2.

 The process shown in Figure 3 consists of the following three steps, namely:

Step S31, wherein the base station 2 selects, according to the single cell scheduling method, each mobile terminal that is separately served on at least one frequency band in each scheduling period, and the mobile terminals include the mobile terminal 4 and the cell 0 not shown in the figure. Other mobile terminals. Here, the base station 2 can use various existing or future proposed single cell scheduling means, typically as proportional fair (PF) scheduling. For a frequency band j, the base station 2 can be based on the following: ₍₁₎

其中， 选择令^"最大的那个移动终端 , 表示移动终端 i 在频带 j上的即时数据率， 而 表示移动终端 i在过去一个时间段 内的平均吞吐量。

The mobile terminal that selects the largest is the instant data rate of the mobile terminal i in the frequency band j, and represents the average throughput of the mobile terminal i in the past time period.

Obtaining step 32, where the base station 2 acquires interference strength indication information corresponding to the cell 0 where the base station is located, which indicates the interference strength that the cell 0 bears on the at least one frequency band. Specifically, each mobile terminal in the cell 0 where the base station 2 is located receives a pilot signal from another base station, and reports the received strength of the pilot signal to the base station 2, and the base station 2 calculates the corresponding other base station and reports reception. The downlink channel gain between the mobile terminals of the strength, as described above, can also be calculated by the mobile terminal and reported to the base station 2. In addition, the base station 2 also calculates the sum of the interference noise received by the local cell 0 in the frequency band j in a superframe in the past time period, which may be a weighted sum ^^ ^N , , 】 ⁼ , ' · · ^Κ .

2 ^Rj - 1

The sending step 33 is where the base station 2 sends the acquired interference strength indication information corresponding to the cell 0 to the corresponding base station in the at least one other base station. For example, the base station 2 transmits the downlink channel gain between the base station 3 and the mobile terminal 4 to the base station 3, which is not shown in the figure. The downlink channel gain between the other base station shown and the mobile terminal 4 is transmitted to the other base station. In addition, the sum of the interference noise received by the cell 0 in which the base station 2 is located in the past time period is transmitted to each of the at least one other base station.

 The signaling interaction between the base stations described above is generally performed by a backhaul link between the base stations.

 In the above, the signaling interaction between the base stations has been described in more detail, and the description of the determining step S22 shown in Fig. 2 is continued below.

 In order to finally determine the allocated downlink transmit power on each frequency band, the base station 2 establishes an association relationship between the two in addition to the information related to the inter-cell interference provided by other base stations. This relationship or determination is generally configured at the base station 2 in the form of pre-stored information. In various embodiments of the invention, the relationship between the two depends on different content:

 First embodiment: the association relationship is for the following purpose: - the downlink transmission power allocation of the base station 2 in at least one frequency band is such that the throughput achieved in the cell 0 where the base station 2 is located and the cell in which at least one other base station is located The sum of the throughput reductions is large, and a more detailed explanation of this purpose will be given below in conjunction with the formula.

 Second Embodiment: The association relationship is for the purpose of: - Base station 2 allocates less downlink transmit power or no allocation on each frequency band in which at least one other base station is located is sensitive to interference from base station 2, and at least one other The cell pair where the base station is located can be selected from the base station, and the base station can select one of the power allocations for the current according to the actual situation of the channel shield, the small interval interference, and the complexity of the operation.

 The following is a detailed description of the first and second embodiments. Among them, although mainly based on the discussion of the OFDAM link, those skilled in the art understand that the various embodiments of the present invention are fully applicable to a variety of other network environments including SC-FDMA. First embodiment

The first embodiment will achieve the optimization of the TMU through the allocation of resources, especially power, which can be understood by those skilled in the art by reading the following, in the first embodiment of the present invention. This distributed solution is completely different from the traditional TMU-based solution with centralized scheduling and resource allocation. One of the differences is that, in the first embodiment, the TMU corresponds to the sum of the data rate achieved by the power allocation of the base station 2 in the own cell and the data rate reduction in other cells caused thereby, and Pursue the maximization of such a TMU. By maximizing the respective TMUs distributed in each cell, the advantages of the overall capacity of the system are improved. The TMU in the cell 0 in the first embodiment may be represented by the formula (1), wherein the left side of the equal sign indicates the TMU in the cell, and the first item on the right side of the equal sign indicates the data rate implemented in the cell 0, generally Positive value, the second term indicates the data rate loss of other cells due to the power allocation action in cell 0, which is generally a negative value, and the algebraic sum of the two represents the data of the power allocation in the cell 0 for the entire network. Rate contribution, of course, this contribution may not be positive.

 (2)

 Where / is the number of the mobile terminal, J' is the number of the frequency band (1) The right side of the medium number can also be represented by the formulas (2) and (3):

 R

中， 等号右边的第一项 即考虑了小区 0 内的基站 2的下行发射功率 一个其它小区 k中的新的数 Wherein, "representing the downlink transmission power that the base station 2 is to allocate to the mobile terminal i in the frequency band j, representing the downlink channel gain between the mobile terminal i and the base station 2 to which it belongs, that is, the cell 0 is in the frequency band j in the past time period. In the equation (3), ^, indicates that the base station 2 in the cell 0 is on the frequency band j in the other cell k caused by the downlink power allocated to transmit the downlink signal to the mobile terminal i. The data rate loss is called the adjacent cell rate loss (ACRL). In this paper, ACRL has at least two explanations, one is limited to neighboring cells, that is, the pair is excluded from the current cell. The interference of the cell; one is not limited to the neighboring cell, and may also involve a cell that is not adjacent to the current cell but still generates mutual interference. Where, Equation (4) can be expanded into Equation (5): its

In the first item on the right side of the equal sign, the downlink transmit power of the base station 2 in the cell 0 is considered, and the new number in the other cell k

则为不考虑小区 0内的 基站 2的下行发射功率分配时， 其它小区 k中本来的数据率。 具体According to the rate. And the second item to the right of the equal sign

The original data rate in the other cell k when the downlink transmit power allocation of the base station 2 in the cell 0 is not considered. specific

G ^{K) represents the downlink channel gain between the base station 2 in the cell 0 as the interference source and the interfered mobile terminal ^ in the cell k; ^N j represents the sum of the interference noise of the cell k in the frequency band j in the past time period, It does not include interference from cell 0; it represents the downlink transmit power allocated in band k within cell k, and "the channel gain between the other base station k and its selected mobile terminal (in band j).

 It can be seen that ^ ' in equation (5), that is, ACRL depends on multiple parameters, and the expression of ACRL is simplified by the stepwise approximation in 6):

 Since the ACRL is repeatedly approximated in a larger direction, the interference of the cell 0 to the outside is conservatively estimated to be a large value, thereby facilitating the limitation of the interference strength of the cell 0 to other cells. Of course, the present invention does not limit the solution for directly performing power allocation using the approximate amount in the middle of equation (6).

Through equation (6), ACRL is approximated as a linear function of the distributed power. This linear function is also the upper bound of ACRL, even though the actual ACRL may not really take this. A large numerical value. Hereinafter, ACRL is defined by the formula (7):

 It is not difficult to see that the content in the parentheses is the ACRL in the inner band j′ of the cell k brought about by the power allocation of the unit quantity, and thus, the unit quantity allocated by the base station 2 in the cell 0 in the frequency band j The total ACRL in at least one other cell caused by the downlink transmit power may be expressed as (8)

U凤 j ( 8)

 The number of the mobile terminal is omitted, and the relationship between the interference strength indication information sent by each other base station, such as (^ and N, and the last power allocation of the base station 2, can be expressed as follows:

* = argmax _/ , ^U(Rj)

( 9)

 Wherein, the number of the frequency band and j=l,...J, J is the number of the at least one frequency band, and is the downlink transmission power allocated by the base station 2 in the frequency band ', where is the frequency band of the base station 2 and the base station 2 The channel gain between the selected mobile terminal, for example, the mobile terminal 4, is the sum of the interference noise received by the cell in which the base station 2 is located in the band_/ for a period of time,

A is the label of the other base station and A=1,...K, K is the number of at least one other base station, and ^G is the channel gain between the base station 2 and the mobile terminal selected by the other base station k in the frequency band j, 〉 Indicates the sum of the interference noise received by the cell in which the other base station is located in the frequency band j for a period of time.

max ( 10) 于是， 式 （9) 中明确了其它基站提供给基站 2的 G 和 N 这两项 干扰指示信息与最终的功率分配 之间的关联关系 , 再通过步骤 S23 中的求解， 即可进行功率分配。 因此， 在实际应用时， 步骤 S22可以体 现为调取预先保存的式（9) , 步骤 S23则是将步骤 S21中得到的信息 代入式（ 9 )并基于下文来计算和确定在各频带 j上最适合的分配功率， 并进行功率分配。 下面是步骤 S23 的几种实现方式， 本领域技术人员还可以利用 其它的方式来实现步骤 S23,且均不脱离本发明的精神并落入随附权 利要求书限定的保护范围之内。 一种求解式（9)-( 10)的算法是，使用拉格朗日松弛法（Lagrangian relaxation )将式 （ 10) 并入式 （9) , 这一双重优化的求解问题由下 式给出： Considering the base station 2's own transmit power limit, the restrictions in equation (10) can be reintroduced:

Max (10) Then, in Equation (9), the relationship between the interference indication information of the G and N provided by the other base station to the base station 2 and the final power allocation is clarified, and then the step S23 is passed. In the solution, the power distribution can be performed. Therefore, in practical application, step S22 may be performed to retrieve the pre-stored formula (9), and step S23 is to substitute the information obtained in step S21 into equation (9) and calculate and determine the frequency band j based on the following. The most suitable is to distribute power and perform power distribution. The following is a few implementations of the step S23, and those skilled in the art can also implement the step S23 in other ways, without departing from the spirit of the invention and falling within the scope of protection defined by the appended claims. An algorithm for solving equations (9)-(10) is to incorporate equation (10) into equation (9) using Lagrangian relaxation. The problem of solving this double optimization is given by :

g* = min _A θ(λ) ( li)

θ{λ) p j

 (12)

The solution of equation (12) is given by equations (13) - (14)

θ) (15) 其中， 表示一个正的步长， 且满足下式: lim 7,.—一oo S' = 0

γ = \n2 + UACRL _i (14) To find the most suitable Lagrangian factor to minimize the difference between the double optimization and the initial, use a subgradient search for A, the search process is as follows: i( / + l)

θ) (15) where, represents a positive step size, and satisfies the following formula: Lim 7,.—one oo S' = 0

 ▽ denotes the double object WA) for the sub-gradient of l. For the double optimization problem in equation (12), the secondary gradient is the difference between the power limit and the total power at a given one, expressed by:

从上式， 当任一频带上的功率分配增加或减少时， 总的 TMU都不 再增大， 那么功率的调整即可结束。 为了实现最佳的功率分配， 可以将 M-TMU较小的频带上的功率移 至 M-TMU较大的频带上， 从式（18 ) 可以看出， M-TMU是频带发射 功率 的单调减函数。 此种方法使 M-TMU的分布更加均匀， 最终， 所 有频带上的 M-TMU变为定值， 此种方法可以用以下语句来表示： Another way to implement the power allocation in step S23 is to iteratively allocate power to the frequency band associated with the maximum boundary throughput utility (M-TMU), where the M-TMU value on band j is as follows:

From the above equation, when the power allocation in any frequency band increases or decreases, the total TMU does not increase any more, and the power adjustment ends. In order to achieve optimal power allocation, the power in the smaller frequency band of the M-TMU can be shifted to the larger frequency band of the M-TMU. As can be seen from equation (18), the M-TMU is a monotonic reduction of the band transmission power. function. This method makes the distribution of M-TMU more uniform. Finally, the M-TMU in all frequency bands becomes a fixed value. This method can be expressed by the following statement:

I max - η / mi.n ,

While > ^Δ do

 ^7 max + ^7 mi

P_Jmin - AP For 7 _min = arg min . η,

P _Jmin - AP

For 7 _max = arg max, η, P 』 = 匪 + Δ ; that is, update the M-TMU in the band 7 _min and _max ;

 End while

Where Δ// and ΔΡ are system-defined parameters. Second embodiment

 The base station 2 will allocate lower or no power allocation on a frequency band having a larger downlink transmission interference to other base stations, and more distributed downlink transmission power in a frequency band which does not cause a large interference to downlink transmissions of other base stations.

 In order to characterize the above-mentioned interference, a non-limiting example is to use ACRL in other cells, and the ACRLs in different frequency bands are independent of each other, so that very efficient resource multiplexing can be performed between cells.

 Considering the interference problem of the cell 0 to other cells, in an interfered cell k, the mobile terminal is scheduled by the base station k to the same frequency band as the mobile terminal 4. Therefore, the ACRL caused by the cell 0 can be Give:

其中， 表示作为干扰源的小区 0中的基站 2与小区 k中被干 扰的移动终端 ^之间的下行信道增益； ^ 表示小区 k过去一个时间 段内在频带 j上的干扰噪声总和，其中不包括来自小区 0的干扰； ^Ρ』 表示小区 k内分配在频带 j上的下行发射功率， 表示小区 0内分配 在频带 j上的下行发射功率， 而 "则是其它基站 k与它在频带 j上所 选择的移动终端 （ ^ ) 之间的信道增益。

Wherein, the downlink channel gain between the base station 2 in the cell 0 as the interference source and the interfered mobile terminal ^ in the cell k is represented; ^ represents the sum of the interference noise in the frequency band j in the past time period of the cell k, which does not include Interference from cell 0; ^Ρ 』 represents the downlink transmit power allocated in frequency band j in cell k, indicating the downlink transmit power allocated in band 0 in cell 0, and "the other base station k and its in band j Channel gain between selected mobile terminals (^).

Thus, the data rate achieved by cell k on band j is expressed as:

From equation (20):

 When we substitute equation ( 21 ) into equation ( 19 ) we can get A(, )= log (22)

 The total ACRL in all other cells of cell 0 is expressed as

=

于是， ACRL可以作为确定基站 2发射功率的限制因素， 也即， 限 制功率分配对其它小区的负面影响， 本例中， 在频谱上基于下式分配功 率：

Therefore, the ACRL can be used as a limiting factor for determining the transmit power of the base station 2, that is, limiting the negative impact of the power allocation on other cells. In this example, the power is allocated based on the spectrum:

AR _≡ , V/· (24)

 N, 2

 Of course, considering the limited transmit power of the base station 2 itself, equation (25) can be added to further limit the power allocation:

V corp ^w = p max (25) Then, in equation (24), the interference G) provided by the other base station to the base station 2 and the relationship between the two interference indication information and the final power allocation i are determined, and then the steps are passed. The solution in S23 allows power distribution. Therefore, in practical application, step S22 may be embodied by retrieving the pre-stored formula (24), and step S23 is to substitute the information obtained in step S21 into equation (24) and calculate and determine the frequency band j based on the following. The most suitable is to distribute power and perform power distribution.

 The following three less complex algorithms are introduced to implement step S23 in the second embodiment: Algorithm 1

Equation (23) can be transformed into: 2

: 对它进行一阶泰勒 ( Taylor )近似， 由下式表示：

之间的线性关系极大地简化了小区 0内的功率分配 log(l + ) < X, e [0,+oo) this is

: A first-order Taylor approximation is given to it, which is represented by:

The linear relationship between them greatly simplifies the power allocation in cell 0 log(l + ) < X, e [0, +oo)

process. In addition, due to 1η2, the algorithm based on equation ( ₂₇ ) implements to limit inter-cell interference.

小区 0内的单 位量的功率分配所导致的 ACRL， 也称为 UACRL。 它表征了其它小区 对于小区 0内的功率分配的敏感度， 因此， UACRL可以作为如何在频 谱上分配功率的一个因素， 这实际上是一种以接收端为中心的解决方 案， 其中， ： On the right side of equation (27), in parentheses

The ACRL caused by the unit amount of power allocation in the cell 0 is also called UACRL. It characterizes the sensitivity of other cells to the power allocation within cell 0. Therefore, UACRL can be a factor in how to distribute power across the spectrum, which is actually a receiver-centric solution, where:

Corpse ⁽⁰⁾ oc

 Base station 2 is based on base channel gain and is calculated

U determines the initial

再计算功率扩

Recalculate power expansion

∑Ρ厂p _m (31) 』

 1 x>0

 U(x)

And according to. ) ^{= jP} to allocate power, where, , , I ⁰ other

 Algorithm 2

Display with high bandwidth data with border UACRL

It is more susceptible to inter-cell interference and is released to release it. Equation (28) can be further simplified to:

GG[ ^k \2 ^R -\

Since ∑^3⁄4 ^≥ ∑, algorithm 2 is compared to algorithm 1

keK N ^(k) 2 ^Rj

It is more conservative because it sacrifices average user throughput in exchange for greater performance gains at the cell edge. Description 2 is no longer expanded here, because ^_N in algorithm 1 is replaced by N

2 ^RJ - 1

available.

 Algorithm 3

 Both algorithms 1 and 2 use a first-order approximation, and a more accurate approximation is the following two, which are represented by:

If the same ACRL value is used on the frequency, ie, the transmit power in band j can be calculated as: ^λ) +41 ₂ C λ

 p

 2λ 2λ.. (31)

 C = 2^ one 1

In equation ( ), c is a system-dependent parameter that can be determined based on:

 Estimate c by using mathematical methods to solve equation (32)

After calculating and ^ based on equation (30), the upper and lower limits of c can be determined according to the following formula:

其中^， ， A₂和 分别为 l和 j',2的最大和最小值 < 通过以下过程， 即可估计出 C: (33)

Where ^, , A ₂ and the maximum and minimum values of l and j', 2, respectively, can be estimated by the following procedure:

While (c - c _min )〉& do

Let c = (c _max +c _min )/2

2λ 7,2 if

c max = c

c max = c

 Else

c mm . = c Endif end while

 It should be understood that the use of a constant ACRL in the spectrum of the present invention is only a mode in a specific embodiment of the present invention, and the present invention does not exclude the use of different ACRL restrictions in different cells, which is preferred because these cells have different priorities. level.

 In order to better demonstrate the various advantages of the present invention, the simulation results under specific conditions are described below, taking the second embodiment as an example. The simulation conditions are as follows:

 Consider a hexagonal grid of seven cells in which 210 user terminals are evenly distributed, using enclosing to avoid edge effects, and also simulating a complete inter-cell interference scenario.

 Performance of the three algorithms in the second embodiment

可见， 算法 1和算法 3实现了平均用户吞吐量的些许提升， 且算 法 3因应用了更为准确的 ACRL模型而在小区边缘吞吐量的表现上优于 算法 1 。 另一方面， 算法 2在获得最大的 25%小区边缘性能提升的同 时， 产生了平均吞吐量上的 2.3%的负增长。 如上所述地， 因为算法 2 相比于其它两者更为保守。 另外， 这三种算法的表现和全复杂度的常量 ACRL方式十分接近。

It can be seen that Algorithm 1 and Algorithm 3 achieve a slight increase in average user throughput, and Algorithm 3 is superior to Algorithm 1 in the performance of cell edge throughput due to the application of a more accurate ACRL model. On the other hand, Algorithm 2 produced a negative growth of 2.3% on average throughput while achieving a maximum 25% cell edge performance improvement. As mentioned above, because Algorithm 2 is more conservative than the other two. In addition, the performance of these three algorithms is very close to the full complexity of the constant ACRL approach.

 In Tables 2 and 3, the relationship between the increase in user throughput and the increase in cell edge throughput displayed during the simulation is shown in relation to the ACRL extension index α and the power extension index /?, and /? can be seen in the above. Related content.

 Table 2: Interference channel gain G) including path fading, lognormal fading and fast fading

1 1/3 -2.66% 27.26%

1 1/3 -2.66% 27.26%

0.95 1 1.33% 22.02%

0.95 2/3 1.66% 23.31%

0.95 1/3 1.00% 25.68%

0.90 1 2.99% 19.61%

0.90 2/3 1.99% 23.06%

0.90 1/3 -0.33% 30.12%

0.85 1 3.65% 18.16%

0.85 2/3 1.66% 24.64%

0.85 1/3 -2.32% 33.20%

0.80 1 3.99% 16.53%

0.80 2/3 1.33% 25.45%

0.80 1/3 -3.99% 36.15%

0.75 1 4.32% 15.26%

0.75 2/3 0.66% 26.44%

0.75 1/3 -5.98% 37.07% Table 3: Interference channel gains only include path fading and lognormal fading

ACRL extension refers to power expansion index, average user throughput, cell edge throughput, α β amount increase, growth

1 1 -1.66% 15.78%

1 2/3 -2.33% 18.62%

1 1/3 -4.65% 23.96%

0.95 1 0.00% 14.53%

0.95 2/3 -1.66% 18.84%

0.95 1/3 -5.65% 27.74%

0.90 1 0.66% 12.44%

0.90 2/3 -1.66% 20.87%

0.90 1/3 -7.30% 30.40%

0.85 1 1.00% 11.30%

0.85 2/3 -2.00% 21.01%

0.85 1/3 -8.64% 32.25%

0.80 1 1.33% 11.39%

0.80 2/3 -2.33% 22.22%

0.80 1/3 -9.97% 32.66%

0.75 1 1.66% 10.60%

0.75 2/3 2.99% 22.95%

0.75 1/3 -11.63% 32.07% Based on the above detailed description of the method provided by the present invention, a distributed resource allocation apparatus for reducing downlink channel interference in a base station provided in the present invention is generally described below, which is typically located Among the base stations in the wireless network, for example, the base station 2 and the base station 3 shown in FIG. 1, and include:

 An obtaining device 401, configured to obtain interference strength indication information sent by at least one other base station, where the interference intensity indication information sent by each other base station indicates the interference strength of the cell where the other base station is located in at least one frequency band The related information corresponds to the aforementioned step S21.

 A determining means 402 is configured to determine an association relationship between the interference strength indication information sent by the at least one other base station and the downlink transmit power allocation of the base station on the at least one frequency band, corresponding to the foregoing step S22.

 A distribution device 403 is configured to allocate downlink transmit power of the base station to the at least one frequency band according to the determined association relationship and the interference strength indication information sent by the at least one other base station, corresponding to the foregoing step S23.

 Further, the distributed resource allocation device 40 further includes:

 The scheduling device 404 is configured to select, according to the single cell scheduling method, each mobile terminal that is separately served on the at least one frequency band in each scheduling period, corresponding to the foregoing step S31.

 The acquiring device 405 is configured to obtain interference intensity indication information corresponding to the cell where the base station is located, where the interference strength of the cell where the base station is located is in the at least one frequency band, which corresponds to the foregoing step S32.

 The transmitting device 406 is configured to send the acquired interference strength indication information corresponding to the cell where the base station is located to the corresponding base station in the at least one other base station, corresponding to the foregoing step S33.

It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments are to be considered as illustrative and not limiting, the scope of the invention is The scope of the invention is intended to be embraced by the appended claims. Any reference signs in the claims should not be construed as limiting the claim. In addition, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. A plurality of units or devices recited in the system claims can also be implemented by a unit or device by software or hardware. The first, second, etc. words are used to denote names, and do not denote any particular order.

Claims

Claim A distributed resource allocation method for reducing downlink channel interference in a base station in a base station, comprising the following steps:  An obtaining step, wherein the base station obtains interference strength indication information sent by at least one other base station, where the interference intensity indication information sent by each other base station indicates that the cell where the other base station is located is at least one frequency band Information about the intensity of the disturbance;  a determining step, wherein the base station determines an association relationship between the interference strength indication information sent by the at least one other base station and the downlink transmission power allocation of the base station on the at least one frequency band;  An allocation step, wherein the base station allocates downlink transmit power of the base station on the at least one frequency band according to the determined association relationship and the interference strength indication information sent by the at least one other base station.  2. The distributed control method according to claim 1, wherein the determining step determines the association relationship according to one of:  a downlink transmit power allocation of the base station on the at least one frequency band such that a throughput achieved in a cell in which the base station is located and a throughput decrease in a cell in which the at least one other base station is located And larger;  b. The base station allocates less downlink transmit power or no allocation on each frequency band in which the cell where the at least one other base station is located is more sensitive to interference from the base station, and the cell pair in the at least one other base station is located A larger downlink transmission power is allocated on each frequency band in which the interference of the base station is less sensitive.  The distributed control method according to claim 1 or 2, wherein the interference strength indication information sent by any other base station for any one of the at least one frequency band includes the following information: The other base station is a gain of a downlink channel between the mobile terminal selected by the frequency band and the base station, based on the mobile terminal selected by the other base station on the frequency band Determining the strength of the received downlink signal from the base station;  The sum of the interference noise received by the cell in which the other base station is located in the frequency band over a period of time. 4. The distributed control method according to claim 2, wherein _a first said item represented by the following formula: /* = argmax corpse

Where j is the label of the frequency band and j=l,...J, J is the number of the at least one frequency band, and the downlink transmission power allocated by the base station in the frequency band j is the base station and the base station The channel gain between the selected mobile terminals on the frequency band j is the sum of the interference noise received by the cell in which the base station is located in the frequency band j for a period of time, k is the label of the other base station and k=l, .. .K, K is the number of the at least one other base station, indicating the downlink channel gain between the mobile terminal selected by the other base station k in the frequency band j and the base station, indicating that the cell in which the other base station k is located is within a time period. The sum of the interference noise received in band ₇ ·. The distributed control method according to claim 2, wherein the throughput caused by the interference of the downlink power allocation of the base station in the b item to the cell where the at least one other base station is located is The drop is represented by the following formula:

Wherein, is the label of the frequency band and =i,...j, «/ is the number of the at least one frequency band, / is the downlink transmission power allocated by the base station on the frequency band j, and k is the label of the other base station and k=l,...K, κ is the number of the at least one other base station, indicating the downlink channel gain between the mobile terminal selected by the other base station k on the frequency band j and the base station, ^? Indicates the sum of the interference noise received by the cell where the other base station k is located in the frequency band j, and R is expressed by:

Where ^F j is the downlink transmit power allocated by the other base station k in the frequency band j, and is the channel gain between the other base station k and the mobile terminal selected by the other base station k in the frequency band j.  The distributed control method according to claim 1, further comprising: a scheduling step, wherein the base station selects to separately serve on the at least one frequency band based on a single cell scheduling method in each scheduling period Each mobile terminal;  And an acquiring step, where the base station acquires interference intensity indication information corresponding to a cell where the base station is located, where the interference strength of the cell where the base station is located is at least one frequency band;  And a sending step, where the base station sends the acquired interference strength indication information corresponding to the cell where the base station is located to the corresponding base station in the at least one other base station. A distributed resource allocation apparatus for reducing downlink channel interference in a base station in a base station, comprising:  An obtaining device, configured to obtain interference strength indication information sent by at least one other base station, where the interference intensity indication information sent by each other base station indicates the interference strength of the cell where the other base station is located in at least one frequency band Corresponding information, a determining device, configured to determine an association relationship between the interference strength indication information sent by the at least one other base station and the downlink transmit power allocation of the base station on the at least one frequency band;  And a distribution device, configured to allocate downlink transmit power of the base station on the at least one frequency band according to the determined association relationship and the interference strength indication information sent by the at least one other base station.  8. The distributed resource allocation apparatus according to claim 7, wherein the determining means determines the association relationship according to one of: a downlink transmit power allocation of the base station on the at least one frequency band such that a throughput achieved in a cell in which the base station is located and a throughput decrease in a cell in which the at least one other base station is located And larger; b. The base station allocates less downlink transmit power or no allocation on each frequency band in which the cell where the at least one other base station is located is more sensitive to interference from the base station, and the cell pair in the at least one other base station is located A larger downlink transmission power is allocated on each frequency band in which the interference of the base station is less sensitive.  The distributed resource allocation apparatus according to claim 7 or 8, wherein the interference strength indication information sent by any other base station for any one of the at least one frequency band includes the following information:  The gain of the downlink channel between the mobile terminal selected by the other base station and the base station is determined based on the strength of the downlink signal received by the mobile terminal selected by the other base station on the frequency band from the base station ;  The sum of the interference noise received by the cell in which the other base station is located in the frequency band over a period of time.  10. The distributed resource allocation apparatus according to claim 8, wherein the item a is represented by the following formula: /* = argmax

Where j is the label of the frequency band and j=l,...J, J is the number of the at least one frequency band, and the downlink transmission power allocated by the base station in the frequency band j is the base station and the base station The channel gain between the selected mobile terminals on the frequency band j is the sum of the interference noise received by the cell in which the base station is located in the frequency band j for a period of time, k is the label of the other base station and k=l,... K, K is the number of the at least one other base station, and indicates the downlink channel gain between the mobile terminal selected by the other base station k on the frequency band j and the base station, ^ ^Α ) indicating that the other base station k is in a cell The sum of the interference noise received in the frequency band j during the time period. The distributed control device according to claim 8, wherein the interference caused by the interference of the downlink power allocation of the base station in the b item to the cell where the at least one other base station is located is The drop in quantity is represented by the following formula: Og  N†, 2

Where j is the label of the frequency band and j=l,...J, J is the number of the at least one frequency band, i) is the downlink transmission power allocated by the base station in the frequency band j, and k is the other base station The number and k=l,...K, K are the number of the at least one other base station, "representing the downlink channel gain between the mobile terminal selected by the other base station k on the frequency band j and the base station," Indicates the sum of the interference noise received by the cell in which the other base station k is located in the frequency band j for a period of time, and R is expressed by:

The downlink transmit power allocated to the other base station k on the frequency band j is the channel gain between the other base station k and the mobile terminal selected by the other base station k in the frequency band j.  The distributed resource allocation apparatus according to claim 7, further comprising: scheduling means, configured to, by the base station, select to serve separately on the at least one frequency band based on a single cell scheduling method in each scheduling period Each mobile terminal;  And an acquiring device, configured to acquire interference intensity indication information corresponding to a cell where the base station is located, where the interference strength of the cell where the base station is located is in the at least one frequency band;  And a sending device, configured to send the acquired interference strength indication information corresponding to the cell where the base station is located to a corresponding one of the at least one other base station.  A base station, comprising: a distributed control apparatus for reducing downlink channel interference between base stations according to any one of claims 7 to 12.