CN108696876B - Method and device for distributing cell identity information - Google Patents
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Abstract
The invention discloses a method and a device for distributing cell identity information. Wherein, the method comprises the following steps: generating identity information of a plurality of cells by dividing subcarriers of an orthogonal frequency division multiplexing symbol into a preset number of groups; constructing an optimization model and constraint conditions for distributing the identity information, wherein the optimization model is used for the least identity information used under the condition that the constraint conditions are met, and the constraint conditions comprise: anti-collision constraint conditions and anti-confusion constraint conditions; acquiring interference states of a plurality of cells to be allocated; and solving the optimization model through constraint conditions according to the interference states of the cells to be distributed, and distributing identity information for the cells according to the solving result of the optimization model. The invention solves the technical problem that the physical identifications provided for the cells are limited to cause confusion or conflict of the physical identifications of a plurality of cells when the number of the cells is increased in the prior art.
Description
Technical Field
The invention relates to the field of digital communication, in particular to a method and a device for distributing cell identity information.
Background
In developed countries, the growing population is realizing mobile internet access as a basic requirement, and the human dependence on wireless communication and the importance of the communication market are increasing. It is due to this fact that more user-appealing applications and equipment are being developed to be able to meet consumer needs, which in turn leads to an exponential increase in mobile data traffic. With 5G systems, it is necessary to meet the requirements of 1000 times of capacity target, 10-100 times of wireless connection devices, 10-100 times of user rate, 10 times of battery endurance, etc., which brings new challenges to the communication industry, because the current network cannot meet the expected increase of network traffic, and therefore, further development and cost of cellular networks are required to meet the expected capacity demand.
In this context, heterogeneous networks (hetnets) are considered to be the most promising method to significantly increase network capacity and processing capacity requirements. In heterogeneous networks, small cells, such as metrocells, picocells and femtocells, will achieve a capacity improvement in local areas and hot spots through spatial multiplexing and macro offloading. At the same time, the macro cell will provide greater and reliable coverage for medium and high rate users. However, due to technical limitations, it is not easy to obtain the series of advantages described above. Since heterogeneous networks need to face severe challenges in terms of energy consumption and network management as the number of cells increases. From an environmental point of view, the small cell should operate in an on-demand allocation manner, that is, the cell is activated when there is a connected UE in its vicinity, otherwise the cell is turned off. In a heterogeneous network, a large number of network boundaries also significantly increase the number of cell (re) selections or handovers, and thus the signaling overhead increases. In addition, the difference in small cell and macro cell transmit power also significantly affects the performance of cell edge users and degrades mobility management due to increased handover failure rates and ping-pong handovers. Therefore, a new network architecture is needed in a dense heterogeneous network environment, and the network architecture is easy to deploy, flexible and economical.
A network architecture with separate control plane and user plane is proposed in the current industry and has been developed significantly in the LTE standard R12. In this new network architecture, the control plane and the user plane are separated and no longer need to be transmitted/processed by the same network node. This increases the flexibility of network management, since the small cell can be activated only when specific user data is provided, while the connection of the control terminal is managed through the macro cell. Therefore, the dual connection allows the small cell to have a longer sleep time and enhances the mobility management performance of the network because the small cell does not transmit control information such as paging information any more and the RRC layer of the UE is not handed over to the small cell. Furthermore, dual connectivity also allows small cells to operate in the same or different frequency bands as macro cells, which provides great flexibility in terms of available spectrum and mitigation of interference. As shown in fig. 1a and fig. 1b, a conventional heterogeneous network architecture and a dual connectivity network architecture with separated control plane and user plane are shown, where PSS/SSS (primary/secondary synchronization signal) is a primary/secondary synchronization signal, pbch (physical broadcast channel) is a primary broadcast channel, and crs (cell reference signal) is a cell reference signal. As can be seen from the figure, in the conventional structure, common control information is transmitted in both the macro cell and the micro cell under its coverage, while in the separate structure, the macro cell transmits the common control information, and the micro cell only needs to transmit user information transmission-related information, such as proprietary control information and user data (control & data).
In a dual-connectivity network architecture, good Cell identification and synchronization are crucial to the overall performance of the system, and these processes are closely related to the PCI (Physical Cell Identifier) of the Cell. In the LTE-A system, a PCI is adopted to distinguish a base station and a user in uplink and downlink in the cell synchronization process, namely, a mobile terminal firstly detects a primary synchronization sequence to determine the intra-group number of a cell ID, then detects a secondary synchronization sequence to determine the group of the cell ID, and finally determines a physical cell identification number. From the system perspective, in order to support more multi-cell networking, we hope that the more the number of available PCI resources is better, but this is limited by the physical characteristics of the synchronization sequence, because the excessive requirement of the number of PCIs inevitably causes the detection time of the synchronization sequence to be too long, which makes it impossible to meet the requirement of fast access of the LTE-a system.
In order to solve the above problems, the LTE-a system adopts a compromise method. The LTE-a system designs 504 IDs in total, and divides the IDs into 168 groups, where the group number corresponds to 168 secondary synchronization sequences, each group includes 3 IDs, corresponds to three primary synchronization sequences, and is used to allocate to three sectors under the same base station, that is, each base station configures one group of PCIs. In an actual network, especially for some urban hot spot areas, due to the adoption of a network architecture of a heterogeneous network, it is inevitable that macro cells overlap and small cells are deployed in large quantities to enhance system capacity. The system's requirement for PCI resources may be greater than the number of available PCIs, and therefore cell collisions and confusion must be avoided by PCI multiplexing.
As shown in fig. 2, we present a schematic diagram of cell PCI collision. In fig. 2, cell a and cell B are two adjacent cells, but the system assigns them the same PCI, which results in that the mobile terminals located in the overlapping coverage area of the two cells cannot distinguish the two cells, thereby causing PCI collision in the network. As shown in fig. 3 and 4, we present two kinds of cell PCI confusion. In fig. 3, although cell a and cell B are not adjacent cells, but are adjacent to cell C, the problem of confusion of PCI arises in the system if cell a and cell B use the same PCI. This will result in the mobile terminal in cell C reporting the measurement result to request handover to cell B, and the base station in cell C will not know whether the target cell to handover is cell a or cell B because they have the same PCI. Fig. 4 shows a heterogeneous network scenario, in fig. 4, small cell a and small cell B have the same PCI and are located within the coverage of the same macro base station C, because the macro base station C cannot distinguish the two small cells due to the same PCI, which causes confusion.
It can be known from the above that, the number of cells is increased sharply by introducing a large number of low power nodes, but the number of available cell PCIs that the system can provide is limited, which will result in the limited networking capability of multiple cells of the system, and there will be a large number of cells reusing the same PCI inevitably, and in a super-dense cell network scenario, the distance between adjacent cells is reduced, and multiple cells reuse the same PCI, which will cause the inter-cell distance reusing the same PCI is smaller than the multiplexing distance of the PCI, thereby causing the collision and confusion problem of the PCI in the system, bringing serious interference to the whole system, and finally causing the performance reduction of the whole system.
Aiming at the problem that the number of cells is increased in the prior art, but the physical identifications provided for the cells are limited, so that the physical identifications of a plurality of cells are disordered or collided, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a method and a device for distributing cell identity information, which are used for solving the technical problems that the number of cells is increased, but the physical identifiers provided for the cells are limited, so that the physical identifiers of a plurality of cells are disordered or conflicted in the prior art.
According to an aspect of the embodiments of the present invention, a method for allocating cell identity information is provided, including: generating identity information of a plurality of cells by dividing subcarriers of an orthogonal frequency division multiplexing symbol into a preset number of groups; constructing an optimization model and constraint conditions for distributing the identity information, wherein the optimization model is used for the least identity information used under the condition that the constraint conditions are met, and the constraint conditions comprise: anti-collision constraint conditions and anti-confusion constraint conditions; acquiring interference states of a plurality of cells to be allocated; and solving the optimization model through constraint conditions according to the interference states of the cells to be distributed, and distributing identity information for the cells according to the solving result of the optimization model.
According to another aspect of the embodiments of the present invention, there is also provided an apparatus for allocating cell identity information, including: a generating module, configured to generate identity information of multiple cells by dividing subcarriers of an ofdm symbol into a preset number of groups; a building module, configured to build an optimization model and constraint conditions for distributing identity information, where the optimization model is used to minimize the identity information used when the constraint conditions are satisfied, and the constraint conditions include: anti-collision constraint conditions and anti-confusion constraint conditions; the first acquisition module is used for acquiring the interference states of a plurality of cells to be allocated; and the distribution module is used for solving the optimization model through the constraint condition according to the interference states of the cells to be distributed and distributing the identity information for the cells according to the solving result of the optimization model.
In the embodiment of the invention, the sub-carriers of the orthogonal frequency division multiplexing symbols are divided into the groups with the preset number to generate the identity information of a plurality of cells, an optimization model and a constraint condition for distributing the identity information are constructed, and the identity information is distributed to the cells through the optimization model and the constraint condition according to the interference states of the cells to be distributed. According to the scheme, on one hand, the sub-carriers are grouped to generate the cell IDs, so that the number of the cell IDs is increased, on the other hand, anti-collision constraint and anti-confusion constraint are carried out when the IDs are allocated to the cells, and the problem that in the prior art, the number of the cells is increased, but physical identifications provided for the cells are limited, so that physical identifications of a plurality of cells are disordered or collided is solved.
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. 1a is a schematic diagram of a conventional heterogeneous network architecture according to the prior art;
FIG. 1b is a schematic diagram of a dual-connectivity network architecture according to the prior art;
FIG. 2 is a diagram of a physical cell of a cell indicating a collision;
FIG. 3 is a schematic diagram of a physical cell scrambling of a cell;
FIG. 4 is a schematic diagram of a physical cell scrambling of another cell;
fig. 5 is a flowchart of a method for allocating cell identity information according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an alternative vID for controlling a base station to configure a data base station, according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of an alternative heterogeneous network in accordance with an embodiment of the present invention;
fig. 8 is a schematic diagram of alternative subcarrier locations carrying virtual cell IDs according to an embodiment of the present invention;
FIG. 9 is a schematic illustration of an alternative interference pattern according to an embodiment of the present invention;
fig. 10 is a schematic diagram of an apparatus for allocating cell identity information according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
In accordance with an embodiment of the present invention, there is provided an embodiment of a method for allocating cell identity information, it should be noted that the steps shown in the flowchart of the drawings may be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in an order different from that shown.
Fig. 5 is a flowchart of a method for allocating cell identity information according to an embodiment of the present invention, as shown in fig. 5, the method includes the following steps:
step S51, generating identity information of a plurality of cells by dividing subcarriers of the ofdm symbol into a preset number of groups.
Specifically, the cell is a virtual cell, the identity information of the cell is an ID of the virtual cell, and the Orthogonal Frequency Division Multiplexing (OFDM) symbol is used to carry the virtual ID of the cell.
The preset number of packets may be determined according to the number of subcarriers, and it should be noted that the more the subcarriers are divided into groups, the more virtual IDs are generated, but the smaller the bandwidth of the subcarriers is, so that the grouping needs to be performed while ensuring the bandwidth of each subcarrier after the grouping can ensure the transmission requirement.
Step S53, constructing an optimization model and constraint conditions for distributing the identity information, wherein the optimization model is used for minimizing the used identity information, and the constraint conditions include: anti-collision constraints and anti-confusion constraints.
In an alternative embodiment, when considering avoiding collision and confusion of cell IDs, an integer linear programming model can be used to solve the problem of cell ID assignment, and the parameters and variables are first defined as follows: i e V represents the set of microcells; { i, j }. epsilon.E represents a set of microcell pairs in the interference graph; k belongs to K and is a cell ID set; m belongs to M and represents a macro cell set; r isiRepresents the average number of times cell i is selected during cell selection (reselection), as represented by the weight of cell i that potentially could cause confusion to the system; l im1 denotes that the microcell i is within the coverage of the macro base station m, otherwise lim＝0；xik1 means that the microcell i uses the cell IDk, otherwise xik＝0；ωk1 means that the cell IDk has been used, else ω isk＝0；y ijk1 means that the microcell i and the microcell j use the cell IDk at the same time and cause confusion, otherwise yijk＝0；z i1 means that the microcell i is a source of confusion, otherwise z i0. Then the equation for modeling with integer linear programming is expressed as follows:
still in the above embodiment, the above constraint condition may be as follows:
xik+xjk≤ωk,{i,j}∈E,k∈K (3)
xik·lim+xjk·ljm≤1+yijk,i≠j∈K,m∈M (4)
xik≥yijk,i,j∈V,k∈K (5)
xjk≥yijk,i,j∈V,k∈K (6)
zi≥yijk,i,j∈V,k∈K (7)
the constraint of equation (2) indicates that each small cell is assigned only one ID; the constraint of equation (3) ensures that two small cells interfering with each other use different IDs. The constraint from the formula (4) to the formula (6) represents the relevant constraint that two small cells are out of order when using the same ID and are located under the same macro base station; the final equations (7) to (8) are variables z representing small cells causing confusion with respect to the labeliOf (3) is performed.
Of the above 7 constraints, the two constraints expressed by equation (2) and equation (3) are mainly to ensure that the problem of cell ID collision is avoided in the system. Equations (4) to (8) are to avoid the problem of cell ID confusion in the system. If only the avoidance of cell ID collision is considered in the cell ID allocation process of a system, only the first two constraints need to be utilized, and if the avoidance of cell ID collision and confusion is required at the same time, the allocation scheme needs to satisfy all the constraints.
Step S55, obtaining interference states of a plurality of cells to be allocated.
And step S57, solving the optimization model through constraint conditions according to the interference states of the cells to be distributed, and distributing identity information for the cells according to the solving result of the optimization model.
It is emphasized that whatever PCI configuration scenario, the problems of PCI collision and PCI confusion in the system must be avoided. When a network is deployed, the multiplexing distance of the same PCI needs to be considered, and the network multiplexing interference is reduced, so that the mobile terminal can be ensured to accurately identify the cell.
As can be seen from the above, in the above steps of the present application, the subcarriers of the ofdm symbol are divided into a preset number of groups, the identity information of a plurality of cells is generated, an optimization model and a constraint condition for allocating the identity information are constructed, and the identity information is allocated to the cells through the optimization model and the constraint condition according to the interference states of the plurality of cells to be allocated. According to the scheme, on one hand, the sub-carriers are grouped to generate the cell IDs, so that the number of the cell IDs is increased, on the other hand, anti-collision constraint and anti-confusion constraint are carried out when the IDs are allocated to the cells, and the problem that in the prior art, the number of the cells is increased, but physical identifications provided for the cells are limited, so that physical identifications of a plurality of cells are disordered or collided is solved.
Optionally, according to the foregoing embodiment of the present application, in step S51, the generating the identity information of the multiple cells by dividing the subcarriers of the ofdm symbol into a preset number of groups includes:
step S511, the subcarriers of the ofdm symbol are divided into N groups, where the kth subcarrier group is obtained by taking k and N as a modulus, k is nxm + N, N is greater than or equal to 0 and less than or equal to N-1, and m is greater than or equal to 0 and less than or equal to N-1.
The cell ID is carried by an OFDM symbol and can be implemented by: dividing M subcarriers of the OFDM symbol into N groups, wherein the position k of the nth group of subcarriers satisfies the following conditions: n-mod (k)NN-0, 1,2, …, N-1, … k-0, 1,2, …, M-1; that is, k is modulo N and N is the nth group of subcarriers.
Step S513, generates identity information corresponding to each subcarrier according to the group, the sequence length, and the number of sequences of each subcarrier.
In an alternative embodiment, sequences with a length of L are carried on each group of subcarriers, and S sequences are allocated, for example, S ═ 168 sequences given in LTE-a, and the ID of the virtual cell is determined by the following formula: vID-N + L × S, S-0, 1,2, …, S-1, so the number of available cell IDs that can be provided by the above scheme is at least N × S.
After the ID is allocated to each cell in the system, the base station (i.e., macro base station) needs to be controlled to configure a virtual cell ID for the data base station (i.e., micro cell), as shown in fig. 6, C-BC (control base station) performs vID configuration for the D-BS (data base station), the D-BS performs SCS (subcarrier offset) calculation according to vID (representation sequence) to obtain n, and then performs SCS setting on the nth group of subcarriers to set and carry vID.
In an alternative embodiment, taking an LTE-a system as an example to illustrate a specific implementation manner of the present invention, as shown in fig. 7, a heterogeneous network is composed of a macro cell and a pico cell, where the radius of the macro cell is 500 meters and the power is 43 dBm. The picocell is located under the coverage of the macrocell. This embodiment carries a virtual cell ID by using one OFDM symbol. Assuming that the system has 216 subcarriers, the word carriers are first divided into N-6 groups, and the number of subcarriers in each group is 216/6-36, as shown in fig. 8, and the group with N-0 is called a reference subcarrier. The interval between two adjacent subcarriers in each group is N subcarriers; and then, the cell ID design scheme of LTE-a is adopted for the cells in each group of subcarriers, and the number of secondary synchronization channel sequences with the length of M33 is transmitted on the subcarriers with the interval of N6, and S168 in total, so that such a system can have 6 × 168-1008 cell IDs.
It can be seen from the foregoing embodiments that the cell ID provided by the cell ID generation scheme proposed by the foregoing scheme is greatly improved as compared with 504 cell IDs provided by LTE-a, so that the scheme proposed in this patent can greatly improve the number of available cell IDs in the system, thereby greatly reducing interference caused by cell ID collision and confusion in the system. In addition, the LTE auxiliary synchronization channel sequence is multiplexed, and the backward compatibility of the system can be realized to the greatest extent. And finally, the OFDM symbols carry the cell ID sequence at intervals of N subcarriers, so that the OFDM symbols have N repetitive characteristics in a time domain, and detection and design are facilitated.
As can be seen from the above, the above scheme generates cell IDs through cell sequences, thereby increasing the number of cell IDs in the system.
Optionally, according to the above embodiment of the present application, in step S513, after generating the identity information corresponding to each subcarrier according to the position, the sequence length, and the number of sequences of each subcarrier, the method further includes:
step S515, obtaining the center frequency of the ofdm symbol of the micro base station carrying each identity information according to the center frequency of the ofdm symbol where the macro base station synchronization channel is located and a preset coefficient.
Step S517, broadcasting the center frequency of the ofdm symbol carrying each identity information to the mobile terminal that needs to be connected to the macro base station.
In an alternative embodiment, the virtual ID is assumed to be OFDM symbol with center frequency fvAnd the center frequency of the OFDM symbol where the synchronization channel of the macro base station (or the control base station) is located is fcThen f isvAnd fcHave a definite relationship between them, e.g. fv＝c×fcWhere c is a coefficient and therefore can be configured by the macro base station and told to the mobile terminal (handset, UE for short) through, for example, a broadcast channel.
Optionally, according to the foregoing embodiment of the present application, in step S55, the acquiring the interference states of the multiple cells to be allocated includes: constructing interference matrixes among cells in a plurality of macro base stations; the method for constructing the interference matrix between each cell in the macro base stations comprises the following steps:
step A, detecting that the mobile terminal receives a first signal of a first cell in the first cell and a second signal of a second cell in the first cell.
And step B, if the signal difference between the first signal and the second signal is smaller than a preset threshold value, determining that the first cell and the second cell conflict with each other.
And C, repeating the step A and the step C until the conflict situation between each cell in the macro base station is detected, and obtaining an interference matrix of the macro base station, wherein if the detection result about the first cell and the second cell detected in the first cell is different from the detection result about the first cell and the second cell detected in the second cell, the first cell and the second cell are determined to conflict with each other.
The precondition for solving the PCI collision and confusion problem is that the collision between cells needs to be defined, if at least one terminal u in cell i is subjected to the signal difference p between two cells i, jij＝pjiWithin a predetermined threshold T, it is indicated that small cell i and small cell j collide with each other. Using a binary variable a for collisions between two cellsijExpressed, defined as follows:
if p isijT is less than or equal to T, then aij1. Due to terminal distribution and shadow fading, the equations may not be equal for two identical cells, i.e., aij≠aji. In order to clearly define the conflict, the above steps determine the interference relationship according to the maximum detection result of the first cell and the second cell, namely a, if the detection results of the first cell and the second cell are differentij＝aji＝max(aij,aji)。
In an alternative embodiment, an interference graph of cell nodes in a system is shown in fig. 9. In the system, 6 cell nodes are located in the coverage areas of two macro base stations, wherein the cell nodes 1,2 and 3 are located under the same macro base station, and the cell nodes 4, 5 and 6 are located under the same macro base station. The interference matrix can be obtained according to the interference graph as follows:
optionally, according to the foregoing embodiment of the present application, in step S57, solving the optimization model through a constraint condition according to the interference states of the multiple cells to be allocated, and allocating identity information to the cells according to a solution result of the optimization model, includes:
step S571, extracting preset cells from all cells of the macro base station according to the interference matrix to form a first subset, where the number of cells colliding with the preset cells is greater than a preset value.
Step S573, solving the optimization model for the first subset through the conflict constraint condition and the confusion constraint condition, allocating identity information to the cells in the first subset according to the solution result, solving the optimization model for the other cells except the first subset through the conflict constraint condition, and allocating identity information to the other cells except the first subset according to the solution result.
Steps S571 to S573 are a scheme of assigning IDs to cells by constraint conditions, in which: firstly, selecting nodes which conflict with other nodes with the number larger than a preset threshold value in a system to form a subset; then, performing a double-constraint distribution scheme for simultaneously considering conflict and chaos on the nodes in the subset, and performing a single-constraint distribution scheme for only considering ID conflict on the rest nodes;
optionally, according to the foregoing embodiment of the present application, in step S57, solving the optimization model through a constraint condition according to the interference states of the multiple cells to be allocated, and allocating identity information to the cells according to a solution result of the optimization model, includes:
step S575, allocating identity information to a cell within the macro base station through the constraint condition of the collision prevention, to obtain an initial allocation result.
Step S577, a plurality of cells in the initial allocation result are allocated to cells with the same identity information to form a second subset.
And S579, solving an optimization model for the cells in the second subset through the conflict constraint conditions and the confusion constraint conditions, and distributing identity information for the cells in the second subset according to a solving result.
Steps S575 to S579 are another scheme of assigning IDs to cells by constraint conditions, in which: firstly, ID distribution solution is carried out on cell nodes in a system by adopting collision prevention constraint; then, picking out the nodes which generate chaos to form a subset, wherein the nodes which generate chaos can be defined as nodes which repeatedly use the same cell ID under the coverage of the same macro base station; and finally, carrying out double-constraint solving for avoiding conflict and confusion on the nodes in the mixed and disordered subset.
Optionally, the step S53 of building an optimized model for distributing identity information according to the above embodiment of the present application includes:
step S531, interference matrixes among a plurality of cells in a plurality of macro base stations are constructed.
Specifically, the establishment of the interference matrix between the cells in the macro base stations may be implemented through steps a to C, which are not described herein again.
Step S533, an interference undirected graph of the macro base station is constructed according to the interference matrix, wherein each node of the undirected graph is used for representing each cell in the macro base station, and the connection relationship between the nodes is used for representing the relationship of mutual conflict of the cells.
On the premise that the cell collision situation is clear from the interference matrix, the network can be represented as an undirected graph G ═ (V, E), where V ═ {1,2, …, N } represents a set of cell nodes, E { (i, j): i, j ∈ V: pijT ≦ T is the set of edges given by the interference matrix.
Step S535, constructing an interference graph vertex staining model based on the interference matrix, where colors of all nodes in a macro cell in the interference graph are different, colors of both ends of each edge are different, and a used color is the least.
The above steps solve the optimal cell ID assignment problem using the vertex staining problem of the graph. When optimal allocation is carried out, the problems of preventing cell ID collision and ID confusion can be converted into the problem of vertex coloring of the graph to be solved. Preventing cell ID collision requires assigning a color to each vertex while ensuring that vertices at the ends of a side are colored differently, with the goal of minimizing the color used. While preventing ID confusion requires that two small cells with the same ID cannot be in the same macro cell coverage.
It should be noted here that the number of PCIs required for an allocation scheme that considers both collisions and confusion (double defense constraint) is greater than for an allocation scheme that considers only collisions alone (single defense constraint). Meanwhile, the allocation scheme considering cell ID collision and collision takes too long, so the cell nodes in the system are divided into several subsets and then cell ID allocation is performed, and then corresponding adjustment is performed according to the allocation result. The specific steps are shown in steps S551 to S553 and steps S555 to S559.
Example 2
According to an embodiment of the present invention, there is provided an embodiment of an apparatus for allocating cell identity information,
fig. 10 is a schematic diagram of an apparatus for allocating cell identity information according to an embodiment of the present invention, as shown in fig. 10, the apparatus includes:
a generating module 100, configured to generate identity information of multiple cells by dividing subcarriers of an ofdm symbol into a preset number of groups.
A building module 102, configured to build an optimization model and constraints for distributing identity information, where the optimization model is used for the least identity information used when the constraints are satisfied, and the constraints include: anti-collision constraints and anti-confusion constraints.
A first obtaining module 104, configured to obtain interference states of multiple cells to be allocated.
And the allocating module 106 is configured to solve the optimization model through a constraint condition according to the interference states of the multiple cells to be allocated, and allocate the identity information to the cells according to a solution result of the optimization model.
Optionally, in the foregoing embodiment of the present application, the generating module includes:
and the grouping sub-module is used for dividing the sub-carriers of the orthogonal frequency division multiplexing symbol into N groups, wherein the k-th sub-carrier group is obtained by taking k and N as a modulus, k is N multiplied by m + N, N is more than or equal to 0 and less than or equal to N-1, and m is more than or equal to 0 and less than or equal to N-1.
And the generating submodule is used for generating the identity information corresponding to each subcarrier according to the group, the sequence length and the number of the sequences of each subcarrier.
Optionally, in the above embodiment of the present application, the apparatus further includes:
and the second acquisition module is used for acquiring the central frequency of the orthogonal frequency division multiplexing symbol of the micro base station carrying each identity information according to the central frequency of the orthogonal frequency division multiplexing symbol where the macro base station synchronization channel is located and a preset coefficient.
And the broadcasting module is used for broadcasting the center frequency of the orthogonal frequency division multiplexing symbol carrying each identity information to a mobile terminal needing to be connected to the macro base station.
Optionally, in the foregoing embodiment of the present application, the first obtaining module includes: the building submodule is used for building an interference matrix between each cell in a plurality of macro base stations; wherein, the construction submodule comprises:
the detecting unit is used for detecting that the mobile terminal receives a first signal of a first cell in the first cell and a second signal of a second cell in the first cell.
And the determining unit is used for determining that the first cell and the second cell conflict with each other if the signal difference between the first signal and the second signal is smaller than a preset threshold value.
And the circulating unit is used for circularly executing the detecting unit and the determining unit until the conflict situation between each cell in the macro base station is detected, and obtaining the interference matrix of the macro base station, wherein if the detection result about the first cell and the second cell detected in the first cell is different from the detection result about the first cell and the second cell detected in the second cell, the first cell and the second cell are determined to conflict with each other.
Optionally, in the foregoing embodiment of the present application, the allocating module includes:
and the extraction submodule is used for extracting preset cells from all the cells of the macro base station according to the interference matrix to form a first subset, wherein the number of the cells which conflict with the preset cells is greater than a preset value.
And the first solving submodule is used for solving the optimization model for the first subset through the conflict constraint condition and the confusion constraint condition, allocating the identity information to the cells in the first subset according to the solving result, solving the optimization model for the cells except the first subset through the conflict constraint condition, and allocating the identity information to the cells except the first subset according to the solving result.
Optionally, in the foregoing embodiment of the present application, the allocating module includes:
and the first allocation submodule is used for allocating identity information to the cells in the macro base station through the anti-collision constraint condition to obtain an initial allocation result.
And the second allocation submodule is used for allocating the plurality of cells in the initial allocation result to the cells with the same identity information to form a second subset.
And the second solving submodule is used for solving the optimization model for the cells in the second subset through the conflict constraint condition and the chaos constraint condition and distributing the identity information for the cells in the second subset according to the solving result.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (13)
1. A method for distributing cell identity information is characterized by comprising the following steps:
generating identity information of a plurality of cells by dividing subcarriers of an orthogonal frequency division multiplexing symbol into a preset number of groups;
constructing an optimization model and a constraint condition for distributing identity information, wherein the optimization model is used for minimizing the identity information used under the condition that the constraint condition is met, and the constraint condition comprises the following steps: anti-collision constraints and anti-confusion constraints, the constraints comprising: a constraint that two cells interfering with each other use identity information; the method comprises the following steps that chaotic related constraint occurs when two cells under the same macro base station use the same identity information; and constraints on sources of confusion;
obtaining interference states of a plurality of cells to be allocated, wherein the obtaining of the interference states of the plurality of cells to be allocated comprises: constructing interference matrixes among cells in a plurality of macro base stations;
and solving the optimization model through the constraint condition according to the interference states of the cells to be distributed, and distributing identity information for the cells according to the solving result of the optimization model.
2. The method of claim 1, wherein generating the identity information of the plurality of cells by grouping the subcarriers of the ofdm symbol into a preset number of groups comprises:
dividing sub-carriers of an orthogonal frequency division multiplexing symbol into N groups, wherein the group N of the kth sub-carrier is obtained by taking k as a modulus and taking the remainder, wherein k is Nxm + N, N is more than or equal to 0 and less than or equal to N-1, and m is more than or equal to 0 and less than or equal to N-1;
and generating the identity information corresponding to each subcarrier according to the group of each subcarrier, the sequence length and the number of the sequences.
3. The method of claim 2, wherein after generating the identity information corresponding to each subcarrier according to the position of each subcarrier, the sequence length, and the number of sequences, the method further comprises:
acquiring the center frequency of the orthogonal frequency division multiplexing symbol of the micro base station carrying each identity information according to the center frequency of the orthogonal frequency division multiplexing symbol where the macro base station synchronous channel is located and a preset coefficient;
and broadcasting the center frequency of the orthogonal frequency division multiplexing symbol carrying each identity information to a mobile terminal needing to be connected to the macro base station.
4. The method according to any of claims 1 to 3, wherein constructing an interference matrix between each cell within a plurality of macro base stations comprises:
step A, detecting that a mobile terminal receives a first signal of a first cell in the first cell and a second signal of a second cell in the first cell;
step B, if the signal difference between the first signal and the second signal is smaller than a preset threshold value, determining that the first cell and the second cell conflict with each other;
and C, repeating the step A and the step B until the conflict situation between each cell in the macro base station is detected, and obtaining an interference matrix of the macro base station, wherein if the detection result about the first cell and the second cell detected in the first cell is different from the detection result about the first cell and the second cell detected in the second cell, the first cell and the second cell are determined to conflict with each other.
5. The method of claim 4, wherein solving the optimization model according to the interference states of the cells to be allocated through the constraint condition, and allocating identity information to the cells according to the solution result of the optimization model comprises:
extracting preset cells from all cells of the macro base station according to the interference matrix to form a first subset, wherein the number of the cells which conflict with the preset cells is larger than a preset value;
solving the optimization model for the first subset through the conflict constraint condition and the confusion constraint condition, allocating identity information to the cells in the first subset according to the solving result, solving the optimization model for the cells except the first subset through the conflict constraint condition, and allocating identity information to the cells except the first subset according to the solving result.
6. The method of claim 4, wherein solving the optimization model according to the interference states of the cells to be allocated through the constraint condition, and allocating identity information to the cells according to the solution result of the optimization model comprises:
allocating identity information to the cells in the macro base station through the anti-collision constraint condition to obtain an initial allocation result;
allocating a plurality of cells in the initial allocation result to cells with the same identity information to form a second subset;
and solving the optimization model for the cells in the second subset through the conflict constraint condition and the confusion constraint condition, and distributing identity information for the cells in the second subset according to a solving result.
7. The method of claim 1, wherein constructing an optimized model for distributing identity information comprises:
constructing interference matrixes among a plurality of cells in a plurality of macro base stations;
constructing an interference undirected graph of the macro base station according to the interference matrix, wherein each node of the undirected graph is used for representing each cell in the macro base station, and the connection relationship among the nodes is used for representing the relationship of mutual conflict of the cells;
and constructing an interference graph vertex dyeing model based on the interference matrix, wherein all nodes in one macro cell in the interference graph have different colors, the colors at two ends of each edge are different, and the used color is the least.
8. An apparatus for distributing cell identity information, comprising:
a generating module, configured to generate identity information of multiple cells by dividing subcarriers of an ofdm symbol into a preset number of groups;
a building module, configured to build an optimization model and a constraint condition for distributing identity information, where the optimization model is used to minimize the identity information used when the constraint condition is satisfied, and the constraint condition includes: anti-collision constraints and anti-confusion constraints, the constraints comprising: a constraint that two cells interfering with each other use identity information; the method comprises the following steps that chaotic related constraint occurs when two cells under the same macro base station use the same identity information; and constraints on sources of confusion;
a first obtaining module, configured to obtain interference states of multiple cells to be allocated, where the obtaining of the interference states of the multiple cells to be allocated includes: the building submodule is used for building an interference matrix between each cell in a plurality of macro base stations;
and the distribution module is used for solving the optimization model through the constraint condition according to the interference states of the cells to be distributed and distributing the identity information for the cells according to the solving result of the optimization model.
9. The apparatus of claim 8, wherein the generating module comprises:
the grouping submodule is used for dividing the subcarriers of the orthogonal frequency division multiplexing symbol into N groups, wherein the k-th subcarrier group is obtained by taking k and N as a module, k is N multiplied by m + N, N is more than or equal to 0 and less than or equal to N-1, and m is more than or equal to 0 and less than or equal to N-1;
and the generating submodule is used for generating the identity information corresponding to each subcarrier according to the group of each subcarrier, the sequence length and the number of the sequences.
10. The apparatus of claim 9, further comprising:
the second acquisition module is used for acquiring the central frequency of the orthogonal frequency division multiplexing symbol of the micro base station carrying each identity information according to the central frequency of the orthogonal frequency division multiplexing symbol where the macro base station synchronous channel is located and a preset coefficient;
and the broadcasting module is used for broadcasting the center frequency of the orthogonal frequency division multiplexing symbol carrying each identity information to a mobile terminal needing to be connected to the macro base station.
11. The apparatus of any one of claims 8 to 10, wherein the building submodule comprises:
a detecting unit, configured to detect that a mobile terminal receives a first signal of a first cell in the first cell and that the mobile terminal receives a second signal of a second cell in the first cell;
a determining unit, configured to determine that the first cell and the second cell conflict with each other if a signal difference between the first signal and the second signal is smaller than a preset threshold value;
a circulating unit, configured to execute the detecting unit and the determining unit in a circulating manner until a collision situation between each cell in the macro base station is detected, so as to obtain an interference matrix of the macro base station, where if a detection result of the first cell and the second cell detected in the first cell is different from a detection result of the second cell detected in the second cell, it is determined that the first cell and the second cell collide with each other.
12. The apparatus of claim 11, wherein the assignment module comprises:
an extraction submodule, configured to extract preset cells from all cells of the macro base station according to the interference matrix to form a first subset, where the number of cells that collide with the preset cells is greater than a preset value;
and the first solving submodule is used for solving the optimization model for the first subset through the conflict constraint condition and the confusion constraint condition, allocating identity information to the cells in the first subset according to a solving result, solving the optimization model for the cells except the first subset through the conflict constraint condition, and allocating the identity information to the cells except the first subset according to the solving result.
13. The apparatus of claim 11, wherein the assignment module comprises:
the first assignment submodule is used for assigning identity information to the cells in the macro base station through an anti-collision constraint condition to obtain an initial assignment result;
a second allocation submodule, configured to allocate multiple cells in the initial allocation result to cells with the same identity information to form a second subset;
and the second solving submodule is used for solving the optimization model for the cells in the second subset through the conflict constraint condition and the confusion constraint condition and distributing identity information for the cells in the second subset according to a solving result.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101600212A (en) * | 2009-07-06 | 2009-12-09 | 北京邮电大学 | Improving one's methods of a kind of soft-frequency reuse that is used for ofdm system |
| CN101932140A (en) * | 2009-06-22 | 2010-12-29 | 华为技术有限公司 | Method and base station for adjusting radio frame sending time |
| CN103516449A (en) * | 2013-10-18 | 2014-01-15 | 西安邮电大学 | Serving cell notifying and selecting method, device and system |
| CN103716801A (en) * | 2013-12-05 | 2014-04-09 | 广东省电信规划设计院有限公司 | Physical cell identification (PCI) allocation method and system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110013568A1 (en) * | 2009-07-16 | 2011-01-20 | Raymond Yim | Frequency Allocation in Femtocells of Wireless Networks |
| US8483330B2 (en) * | 2009-09-01 | 2013-07-09 | Wi-Lan Inc. | Methods and apparatus for OFDM symbol synchronization for in-door digital TV reception |
| US9565593B2 (en) * | 2013-05-20 | 2017-02-07 | Qualcomm Incorporated | Techniques for selecting subframe type or for interleaving signals for wireless communications over unlicensed spectrum |
-
2017
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101932140A (en) * | 2009-06-22 | 2010-12-29 | 华为技术有限公司 | Method and base station for adjusting radio frame sending time |
| CN101600212A (en) * | 2009-07-06 | 2009-12-09 | 北京邮电大学 | Improving one's methods of a kind of soft-frequency reuse that is used for ofdm system |
| CN103516449A (en) * | 2013-10-18 | 2014-01-15 | 西安邮电大学 | Serving cell notifying and selecting method, device and system |
| CN103716801A (en) * | 2013-12-05 | 2014-04-09 | 广东省电信规划设计院有限公司 | Physical cell identification (PCI) allocation method and system |
Non-Patent Citations (1)
| Title |
|---|
| 超密集网基于干扰公平及多维协作的虚拟小区生成算法;赵晓宁;《电信科学》;20170920;第20-26页 * |
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