CN102726084B - Frequency reuse method and device - Google Patents

Abstract

The invention discloses a frequency reuse method and equipment for heterogeneous networks. The method of the present invention includes the steps of: determining the adjacent cells of the current cell; receiving information related to the edge frequency bands of the adjacent cells; based on the received information, enabling the micro base station of the current cell to reuse the edge frequency bands of the adjacent cells. The method of the invention can significantly reduce inter-cell interference and improve the throughput of user equipment.

Description

Frequency reuse method and device

technical field

The present invention generally relates to frequency reuse technology, in particular to a frequency reuse method and device for improving the receiving performance of cell edge user equipment through inter-cell interference coordination in a heterogeneous wireless communication system.

Background technique

In a multi-cell wireless communication network, inter-cell interference will be caused when adjacent cells allocate the same frequency band to each user equipment. Currently, there are three main ways to mitigate inter-cell interference: interference randomization, inter-cell interference cancellation, and inter-cell interference coordination (ICIC for short). Since inter-cell interference randomization does not reduce interference, and inter-cell interference cancellation can only eliminate primary interference, the ICIC strategy that focuses on finding the best effective reuse factor is seen as the most promising approach and has been adopted in 3GPP ( It has been extensively studied in the 3rd Generation Partnership Project) LTE (Long Term Evolution).

The ICIC scheme achieves better network performance by coordinating frequency and power allocation to obtain a better reuse factor. Most ICIC schemes are based on the principle of fractional frequency reuse (FFR for short). The principle of FFR is to adopt different frequency reuse factors according to channel conditions and interference situations of various user equipments. For example, all subcarriers are divided into several reuse groups, and different reuse groups correspond to different reuse factors. In addition, the FFR method can also use different transmit power controls for different subcarrier groups to perform inter-cell coordination.

With the increasing demand for data services, heterogeneous network (heterogeneous network, abbreviated as HetNet), as an effective method to improve system capacity and coverage, has been added to 3GPP LTE-Advanced (LTE Evolution) as a research project. A heterogeneous network usually has many low-power nodes (abbreviated as LPN), such as pico, hotzone, femto, and relay stations (Relay nodes, abbreviated as RN). Compared with homogeneous network, inter-cell interference in heterogeneous network is more serious. However, there are few literatures dealing with how to coordinate inter-cell interference in heterogeneous networks.

Therefore, an efficient radio resource management algorithm is needed to mitigate inter-cell interference in heterogeneous networks.

Contents of the invention

In view of the above problems, the present invention provides a frequency reuse method and device in a heterogeneous wireless communication system, which are used to alleviate inter-cell interference in a heterogeneous network.

According to a first aspect of the present invention, there is provided a frequency reuse method for a heterogeneous network, comprising the steps of: determining the neighboring cells of the current cell; receiving information related to the edge frequency bands of the neighboring cells; based on the received information , so that the micro base station of the current cell reuses the edge frequency band of the adjacent cell.

According to the second aspect of the present invention, there is provided a frequency reuse device for a heterogeneous network, including: a determining unit, used to determine the adjacent cells of the current cell; a receiving unit, used to receive the edge frequency band of the adjacent cell Relevant information; a reuse unit, configured to enable the micro base station of the current cell to reuse the edge frequency band of the adjacent cell based on the information received by the receiving unit.

According to a third aspect of the present invention, there is provided a node, which may include the device according to the second aspect of the present invention.

Description of drawings

Through the following description of specific embodiments illustrating the principle of the present invention, combined with the accompanying drawings, other purposes and effects of the present invention will become clearer and easier to understand, wherein:

Figure 1 shows an exemplary heterogeneous network;

2 is a block diagram of a frequency reuse device for a heterogeneous network according to an embodiment of the present invention;

FIG. 3 is a flowchart of a frequency reuse method for a heterogeneous network according to an embodiment of the present invention;

4 is a block diagram of a frequency reuse device for a heterogeneous network according to another embodiment of the present invention;

FIG. 5 is a flowchart of a frequency reuse method for a heterogeneous network according to another embodiment of the present invention;

FIG. 6 is a flowchart of a frequency reuse method for a heterogeneous network according to another embodiment of the present invention;

FIG. 7 is a flowchart of a method for determining a neighboring cell with the greatest interference to a micro base station of the current cell according to an embodiment of the present invention;

FIG. 8 is a flowchart of a method for determining a neighboring cell with the greatest interference to a micro base station of the current cell according to another embodiment of the present invention;

FIG. 9A shows a schematic diagram of frequency and power management of a macro base station according to another embodiment of the present invention;

Fig. 9B shows the frequency band reuse result according to the method shown in Fig. 5;

Fig. 9C shows the frequency band reuse result according to the method shown in Fig. 6;

Fig. 10 shows the comparison of the simulation results according to the method shown in Fig. 5 and the prior art; and

FIG. 11 shows a comparison of simulation results according to the method shown in FIG. 6 and the prior art.

In all the above-mentioned drawings, the same reference numerals indicate the same, similar or corresponding features or functions.

specific embodiment

The present invention will be explained and described in more detail below in conjunction with the accompanying drawings. It should be understood that the drawings and embodiments of the present invention are for exemplary purposes only, and are not intended to limit the protection scope of the present invention.

First, FIG. 1 shows a schematic diagram of a heterogeneous network to which the present invention can be applied.

In the present invention, spectrum resources are allocated to the user equipment directly served by the macro base station according to the reference signal power received from the macro base station. Specifically, the macro base station can send a reference signal to the user equipment directly served by the macro base station in the cell. If the power of the signal received by the user equipment from the macro base station is relatively large, for example, greater than a predetermined power threshold, it can be considered that the user equipment is in the In the inner area of the coverage of the macro base station, the user equipment can then be classified as a cell center user, and the frequency band used for communication between the user equipment and the macro base station is called a central frequency band. If the signal power received by the user equipment from the macro base station is small, for example, less than a predetermined power threshold, it can be considered that the user equipment is in the edge area of the coverage of the macro base station, and then the user equipment can be classified as a cell edge user, and the The frequency band used for communication between the user equipment and the macro base station is called an edge frequency band. That is, the macro base station allocates edge frequency bands to user equipments whose received reference signal power is less than a predetermined power threshold, and allocates a central frequency band to user equipments whose received reference signal power is greater than or equal to a predetermined power threshold.

In addition, the frequency of the edge frequency band of the current cell and the frequency of the edge frequency band of the adjacent cell are orthogonal to each other. For example, the edge frequency band of a macro base station with three sectors may be 1/3 of the available frequency band and be orthogonal to the edge frequency bands of neighboring cells. At this time, the cell edge user equipment is limited to only use this sub-frequency band. The remaining 2/3 of the available frequency band in the cell can be used as the center frequency band used by the user equipment at the center of the cell. Since the center frequency band of a cell may reuse the same frequency resource as the edge frequency band of an adjacent cell, the power corresponding to the edge frequency band of each cell is higher than the power corresponding to the center frequency band of the cell, thereby avoiding inter-cell interference.

It should be noted that when the edge frequency band is not occupied by cell-edge user equipment, it can also be used by cell-internal user equipment.

At present, the heterogeneous network usually has many low-power nodes (lower-power nodes, LPN for short) (such as pico, hotzone, femto, and relay station, etc.), which are called micro base stations in the present invention. In a specific implementation, the micro base station can be a low-power node directly connected to the core network; it can also be used as a relay node to relay the communication of its user terminal to the macro base station, so as to realize the communication between the LPN user terminal and the macro base station.

In the present invention, two aspects of interference are mainly discussed. The first aspect is the interference received by the cell edge user equipment from adjacent cells, and the second aspect is the interference received by the micro base station user equipment.

For exemplary purposes, LTE (Long Term Evolution) FDD (Frequency Division Duplex) downlink transmission with a system bandwidth of 10 MHz is taken as an example in FIG. 1 .

The heterogeneous network in FIG. 1 includes 21 cells in total of 0A, 0B, 0C, 1A, 1B, 1C, . . . , 6A, 6B, and 6C. Cells 0A, 0B, and 0C may share one macro base station, which may be, for example, an evolved base station (also called eNodeB or eNB), such as eNB0, eNB1, . . . , eNB6 shown in FIG. 1 . Each sector of the cell base station has a directional antenna with an included angle of 120°. For example, eNB0 can communicate with user terminals in cells 0A, 0B, and 0C through three directional antennas, thereby forming three sectors around eNB0.

In the heterogeneous network in FIG. 1 , it is assumed that each cell has several physical resource blocks (PRBs). In addition, it is assumed that PRBs in each cell can be divided into three orthogonal frequency bands F1, F2 and F3. FIG. 9A shows a schematic diagram of frequency and power management of a macro base station with three sectors (corresponding to cells 0A, 0B, and 0C) in FIG. 1, wherein the edge frequency band 901 of cell 0A corresponds to F1, and the center frequency band 902 includes F2 and F3; the edge frequency band 903 of cell 0B corresponds to F2, the center frequency band 904 includes F1 and F3; the edge frequency band 905 of cell 0C corresponds to F3, and the center frequency band 906 includes F1 and F2.

In the present invention, the micro base station may be a low-power node such as pico, hotzone or relay node, for example, LPN1 and LPN2 located at the cell edge in the heterogeneous network shown in FIG. 1 . The receiving/transmitting antennas of the LPN and user equipment can be omnidirectional.

It should be pointed out that the above assumptions and limitations of the present invention are only illustrative descriptions, and should not be construed as limitations on the present invention.

FIG. 2 is a block diagram of a frequency reuse device 200 for a heterogeneous network according to an embodiment of the present invention. The device 200 may include: a determining unit 210, configured to determine a neighboring cell of the current cell; a receiving unit 220, configured to receive information related to an edge frequency band of a neighboring cell; a reusing unit 230, configured to The information enables the micro base station of the current cell to reuse the edge frequency band of the adjacent cell.

In the present invention, the frequency reuse device 200 may be a centralized control device capable of knowing the identifiers, resource allocation information, actual usage, real-time change information, etc. of all devices in the heterogeneous network. For example, the frequency reuse device 200 may be a macro base station with comprehensive functions in the network, or another node independent of the base station and user equipment, or included in a node in the network.

Fig. 3 is a flowchart of a frequency reuse method for a heterogeneous network according to an embodiment of the present invention. It should be pointed out that each step shown in FIG. 3 can be executed by corresponding devices shown in FIG. 2 respectively.

In step 301, neighbor cells of the current cell are determined.

In this embodiment, the cell 0A in FIG. 1 is taken as the current cell, so the neighbor cells of the cell 0A are determined in step 301 . It can be determined from FIG. 1 that the adjacent cells of cell 0A are cells 0B, 0C, 6B, 1C, 1B, and 2C.

In step 302, information related to edge frequency bands of neighboring cells is received.

The information related to the edge frequency band of the adjacent cell may include, for example: the identifier of the adjacent cell, the location of the macro base station of the adjacent cell, the frequency range or frequency band of the edge frequency band of the adjacent cell (for example, including the start frequency, the end frequency , frequency bandwidth, etc.) and the corresponding power levels, etc.

In the present invention, the information related to the edge frequency bands of adjacent cells can be stored in the memory in the frequency reuse device shown in Figure 2, or can be stored in any one of the network which can be accessed by the frequency reuse device shown in Figure 2 storage device or any other device.

In this step, the frequency reuse device of the present invention receives information related to edge frequency bands of adjacent cells 0B, 0C, 6B, 1C, 1B, and 2C.

In step 303, based on the received information, make the micro base station of the current cell reuse the edge frequency band of the adjacent cell.

The flow charts shown in FIG. 5 and FIG. 6 provide two specific implementation manners for implementing step 303, which will be described in detail below.

Then, the flow in Fig. 3 ends.

FIG. 4 is a block diagram of a frequency reuse device 400 for a heterogeneous network according to another embodiment of the present invention. The device 400 may include: a determining unit 410, configured to determine a neighboring cell of the current cell; a receiving unit 420, configured to receive information related to an edge frequency band of a neighboring cell; a reusing unit 430, configured to The information enables the micro base station of the current cell to reuse the edge frequency band of the adjacent cell. The reusing unit 430 may further include: determining means 431 and reusing means 432 .

In one embodiment, the determining means 431 is configured to determine the sum of edge frequency bands of each adjacent cell, and the reusing means 432 is configured to enable each micro base station of the current cell to reuse the sum of edge frequency bands. Fig. 5 shows a flow chart of the method corresponding to this embodiment.

In another embodiment, the determining means 431 is used to determine the neighboring cell with the greatest interference to each micro base station of the current cell; Edge bands of adjacent cells. Fig. 6 shows a flow chart of the method corresponding to this embodiment.

In a specific implementation manner given as an example, the determining means 431 may further include: means for obtaining the sector antenna beam direction of a macro base station of an adjacent cell; means for determining a micro base station of the current cell and the A device for the angle between the connection direction of the macro base station of the adjacent cell and the obtained sector antenna beam direction; a device for sorting the determined angles; for sorting the angle corresponding to the minimum angle An apparatus for determining a neighboring cell as the neighboring cell that interferes the most with the micro base station. Fig. 7 shows a flowchart of a method corresponding to this implementation.

In another specific implementation manner given as an example, the determining means 431 may further include: means for obtaining the power of a signal received by a micro base station of the current cell from a macro base station of a neighboring cell; means for sorting the power of the acquired signals; means for determining the neighbor cell corresponding to the signal with the highest power as the neighbor cell with the greatest interference to the micro base station. Fig. 8 shows a flowchart of a method corresponding to this implementation.

Fig. 5 is a flowchart of a frequency reuse method for a heterogeneous network according to another embodiment of the present invention.

In step 501, neighbor cells of the current cell are determined.

This step is similar to the aforementioned step 301. In this embodiment, the cell 0A in FIG. 1 is also used as the current cell, and then it can be determined that the adjacent cells of the current cell 0A are cells 0B, 0C, 6B, 1C, 1B, and 2C.

In step 502, information related to edge frequency bands of neighboring cells is received.

Similar to the foregoing step 302, in this embodiment, the frequency reuse device also receives information related to edge frequency bands of adjacent cells 0B, 0C, 6B, 1C, 1B, and 2C. For example, the identifiers of adjacent cells are CELL _0B , CELL _0c , CELL _6B , CELL _1c , CELL _1B , and CELL _2C ; the locations of macro base stations eNB1, eNB2, and eNB6 of adjacent cells; as shown in FIG. 9A , adjacent cells The frequency range of the fringe frequency bands of 0B, 6B, 1B is F2 and the corresponding power level is α, the frequency range of the fringe frequency bands of the adjacent cells 0C, 1C, 2C is F3 and the corresponding power level is also α. It should be noted that the present invention does not limit the edge frequency bands of adjacent cells to have the same power level, as long as the transmit power of the edge frequency bands of each cell is higher than that of the central frequency band.

In the case where the total transmission power of a cell is set to a predetermined value, assuming that the bandwidths of the frequency bands F1, F2 and F3 are equal, the average transmission power per PRB is normalized to 1, and the average transmission power per PRB for the cell edge frequency band is The transmission power of PRB is α, then the average transmission power of each PRB used in the center frequency band of the cell is (3-α)/2.

In step 503, the sum of the edge frequency bands of each neighboring cell is determined.

According to step 502, it can be seen that the frequency range of the edge frequency bands of the adjacent cells 0B, 6B, and 1B is F2, and the frequency range of the edge frequency bands of the adjacent cells 0C, 1C, and 2C is F3, so the adjacent cells 0B, 0C, and 6B can be obtained The sum of the edge frequency bands of , 1C, 1B, and 2C is the frequency range composed of F2 and F3.

In step 504, make each micro base station of the current cell reuse the sum of the edge frequency bands.

Then, the flow of FIG. 5 ends.

FIG. 9B shows the result of frequency band reuse according to the method shown in FIG. 5 , where LPN1/2 represent the micro base stations LPN1 and LPN2 of the current cell OA. As shown in Figure 9B, LPN1 and LPN2 reuse the sum of the edge frequency bands of the adjacent cells 0B, 0C, 6B, 1C, 1B, and 2C obtained in step 503, that is, reuse the two frequency ranges F2 and F3, respectively, for their users Device service.

In addition, when the cell 0B is used as the current cell, the micro base stations LPN1 and LPN2 in the cell 0B reuse the two frequency ranges F1 and F3 to serve their user equipments respectively.

When the cell 0C is used as the current cell, the micro base stations LPN1 and LPN2 in the cell 0B reuse the two frequency ranges F1 and F2 to serve their user equipments respectively.

In the embodiment shown in FIG. 5, since the frequency bands F2 and F3 used by the micro base stations LPN1 and LPN2 are orthogonal to the edge frequency band F1 of the cell 0A, it can effectively avoid the user equipment of the micro base stations LPN1 and LPN2 of the cell 0A Interference with the edge band from the own cell (ie, cell OA). In addition, since the cell base station reduces the transmission power in its frequency bands F2 and F3, it can effectively reduce the interference between the respective user equipments of the micro base stations LPN1 and LPN2 and the central frequency band from the cell (ie, cell 0A).

In addition, it should be noted that although the micro base station reuses the edge frequency range of the adjacent cell, the transmission power of the micro base station may not change because its own transmission power is much lower than that of the macro base station of the adjacent cell.

Fig. 6 is a flowchart of a frequency reuse method for a heterogeneous network according to another embodiment of the present invention.

In step 601, neighbor cells of the current cell are determined.

This step is similar to the aforementioned step 301 and step 501. In this embodiment, the cell 0A in FIG. 2C.

In step 602, information related to edge frequency bands of neighboring cells is received.

Similar to step 502, in this embodiment, the frequency reuse device also receives information related to edge frequency bands of adjacent cells 0B, 0C, 6B, 1C, 1B, and 2C. For example, the identifiers of adjacent cells are CELL _0B , CELL _0C , CELL _6B , CELL _1c , CELL _1B , and CELL _2C ; the locations of macro base stations eNB1, eNB2, and eNB6 of adjacent cells; as shown in Figure 9A, adjacent cells The frequency range of the fringe frequency bands of 0B, 6B, 1B is F2 and the corresponding power level is α, the frequency range of the fringe frequency bands of the adjacent cells 0C, 1C, 2C is F3 and the corresponding power level is also α. It should be noted that the present invention does not limit the edge frequency bands of adjacent cells to have the same power level, as long as the transmit power of the edge frequency bands of each cell is higher than that of the central frequency band.

In step 603, the neighbor cell that interferes the most with each micro base station of the current cell is determined.

FIG. 7 and FIG. 8 show two exemplary specific implementation manners for implementing step 603 .

Fig. 7 is a flowchart of a method for determining a neighboring cell with the greatest interference to a micro base station of the current cell according to an embodiment of the present invention.

In step 701, the sector antenna beam direction of the macro base station of the adjacent cell is acquired.

The sector antenna beam direction of the macro base station of each cell can be stored in a highly functional macro base station in the entire network system, and can also be stored in the macro base station of each cell, so the frequency reuse device of the present invention can be used from the above functions The highly reliable macro base station or the macro base station of each cell obtains the sector antenna beam direction of the macro base station.

In addition, the frequency reuse device of the present invention can also obtain the sector antenna beam direction of the macro base station by sending a query message to the macro base station in real time and according to the response message.

The sector antenna beam direction of the macro base station in the adjacent cell may be expressed, for example, as the angle between the antenna beam direction and the horizontal plane.

In step 702, the included angle between the line direction of a micro base station of the current cell and the macro base station of the adjacent cell and the obtained sector antenna beam direction is determined.

According to the information related to the edge frequency band of the adjacent cell received in step 502, the locations of the macro base stations eNB1, eNB2, and eNB6 of the adjacent cell can be known.

In step 702, first determine the position of the micro base station LPN1 of the current cell 0A, and then obtain three connection lines according to the position of LPN1 and the positions of the macro base stations eNB1, eNB2, and eNB6, and then obtain the macro base station of the adjacent cell from step 701 The sector antenna beam directions of the macro base stations eNB1, eNB2, and eNB6 are selected according to the sector antenna beam directions of the stations, and then the three connection directions associated with the macro base stations eNB1, eNB2, and eNB6 and the three connection directions associated with the macro base stations eNB1, eNB2, and eNB6 can be used. 9 sector antenna beam directions (because a macro base station has 3 antennas, the three macro base stations eNB1, eNB2, and eNB6 have 9 sector antenna beam directions in total) to calculate 9 included angles. For example, three included angles can be calculated between the connection direction of macro base station eNB1 and LPN1 of cell 0A and the three antenna beam directions of macro base station eNB1, and so on. For LPN1, the macro base station eNB2 and eNB6 are also respectively Three included angles can be calculated, resulting in nine included angles.

Similarly, the other three connections can be obtained according to the location of LPN2 and the locations of the macro base stations eNB1, eNB2, and eNB6, and then use these three connections and the nine sector antenna beam directions of the macro base stations eNB1, eNB2, and eNB6 to calculate 9 angle.

In step 703, the determined included angles are sorted.

The sorting operation is performed separately for the micro base station LPN1 of the current cell 0A, that is, sorting is performed on the calculated 9 included angles related to the LPN1.

In addition, the sorting operation is also performed separately for the micro base station LPN2 of the current cell 0A, that is, sorting is performed on the calculated nine angles related to the LPN2.

In step 704, the adjacent cell corresponding to the smallest angle is determined as the adjacent cell that interferes the most with the micro base station.

In this embodiment, it is assumed that the minimum included angle of the micro base station LPN1 for the current cell 0A is the sector antenna beam direction of the macro base station eNB6 in the cell 6B, so in step 704, the adjacent cell 6B is determined to interfere with the micro base station LPN1 Largest Neighborhood.

Assuming that the minimum included angle of the micro base station LPN2 for the current cell 0A is the sector antenna beam direction of the macro base station eNB2 in the cell 2C, the adjacent cell 2C is determined as the neighbor cell with the greatest interference to the micro base station LPN2.

Then, the flow of FIG. 7 ends.

Fig. 8 is a flow chart of a method for determining a neighboring cell that interferes the most with a micro base station of the current cell according to another embodiment of the present invention.

In step 801, the power of a signal received by a micro base station of a current cell from a macro base station of an adjacent cell is acquired.

For example, by measuring the power of signals received by the micro base station LPN1 of the current cell 0A from adjacent cells 0B, 0C, 6B, 1C, 1B, and 2C, six signal power values can be obtained. Six signal power values can also be obtained by measuring the power of signals received by the micro base station LPN2 of the current cell 0A from adjacent cells 0B, 0C, 6B, 1C, 1B, and 2C.

In step 802, the acquired signals are sorted according to their power.

In this step, a sorting operation is performed on the 6 signal power values related to LPN1 and the 6 signal power values related to LPN2 respectively.

In step 803, the neighbor cell corresponding to the signal with the highest power is determined as the neighbor cell with the greatest interference to the micro base station.

Assuming that the maximum signal power received by the micro base station LPN1 of the current cell 0A is a signal from the macro base station eNB6, and the maximum signal power received by the micro base station LPN2 of the current cell 0A is a signal from the macro base station eNB2, then in step 803, the The neighbor cell 6B is determined as the neighbor cell with the greatest interference to the micro base station LPN1 and the neighbor cell 2C is determined as the neighbor cell with the greatest interference to the micro base station LPN2.

Then, the flow of FIG. 8 ends.

In step 604, each micro base station is made to reuse edge frequency bands of adjacent cells other than the most interfering adjacent cell.

For the small base station LPN1 of the current cell 0A, since the adjacent cell with the greatest interference determined in the example of step 603 is 6B, and the edge frequency band of cell 6B corresponds to F2, what this LPN1 reuses is outside the frequency band F2. Edge bands of adjacent cells. Since the edge frequency band of the adjacent cell of the current cell 0A is F2 or F3, the LPN1 reuses the frequency band F3 other than F2.

For the micro base station LPN2 of the current cell 0A, since the adjacent cell with the greatest interference determined in the example of step 603 is 2C, and the edge frequency band of cell 2C corresponds to F3, what this LPN2 reuses is outside the frequency band F3. Edge bands of adjacent cells. Since the edge frequency band of the adjacent cell of the current cell 0A is F2 or F3, the LPN2 reuses the frequency band F2 other than F3.

Then, the flow of FIG. 6 ends.

FIG. 9C shows the result of frequency band reuse according to the method shown in FIG. 6 . As shown in FIG. 9C , the micro base station LPN1 of the current cell 0A reuses the frequency band F3 to serve its user equipment, and the micro base station LPN2 of the current cell 0A reuses the frequency band F2 to serve its user equipment.

In addition, when the cell 0B is used as the current cell, the micro base station LPN1 in the cell 0B reuses the frequency band F1 to serve its user equipment, and the micro base station LPN2 in the cell 0B reuses the frequency band F3 to serve its user equipment.

When the cell 0C is the current cell, the micro base station LPN1 in the cell 0C reuses the frequency band F2 to serve its user equipment, and the micro base station LPN2 in the cell 0C reuses the frequency band F1 to serve its user equipment.

Using this frequency reuse method, in addition to alleviating the interference between the user equipment of the micro base station and the own cell, it can also remove the main interference from adjacent cells.

For the above radio resource management scheme, the main interference of the cell edge user equipment comes from the central frequency band of the adjacent cell. Since the transmit power of the adjacent cell base stations and micro base stations occupying the central frequency band is much lower than that of the cell edge frequency band, the receiving performance of the cell edge user equipment can be greatly improved. On the other hand, for a micro base station deployed on the edge, the main interference of its user equipment comes from the center frequency band of the current cell and the edge frequency band of the adjacent cell. Due to the reduced transmission power of the base station of the cell in the center frequency band and the distance between the adjacent base stations of the cell and the user equipment of the micro base station of the cell, the user equipment of the micro base station suffers less interference. In particular, when the micro base station adopts the spectrum reuse method shown in FIG. 9C , the inter-cell interference of the user equipment of the micro base station from adjacent cells will be further reduced. For the central user equipment served by the macro base station, since it is relatively close to the serving base station, the frequency reuse scheme has little impact on its performance.

Fig. 10 and Fig. 11 respectively show the comparison of the simulation results between the frequency reuse method according to the present invention and the prior art. In Fig. 10, the micro base station is, for example, a pico node, which is directly connected to the core network. The user equipment of the pico node exchanges information with the core network by directly communicating with the pico node, and FIG. 10 is a comparison between the method shown in FIG. 5 of the present invention and the prior art. In FIG. 11, the micro base station is, for example, an in-band relay node (In-band relay nodes), and the user equipment of the micro base station communicates with the macro base station via the micro base station as a repeater, and FIG. 11 is a diagram of the present invention 6 shows the comparison of the method with the prior art.

First, Table 1 below shows the system parameters used to perform the simulations of FIGS. 10 and 11 :

Table 1 System-level simulation parameters

FIG. 10 shows a comparison of simulation results according to the method shown in FIG. 5 and the prior art.

In a multi-user system, the effects of technical solutions can be compared by considering the fairness among users. For example, a normalized cumulative distribution function (CDF, Cumulative Distribution Function) curve of user throughput can be used to represent this effect. Throughput is generally expressed by the amount of data correctly transmitted per unit time, and the throughput of all users is normalized relative to the system bandwidth.

The two curves shown in FIG. 10 are the normalized user throughput of the method of the present invention and the prior art respectively. Table 2 shows the corresponding system simulation results, representing the corresponding user-average and user-edge (5%) throughputs and their gains. It can be seen that compared with the performance of a heterogeneous system without frequency reuse, the average cell throughput of the present invention is 2.06, which is greater than 1.93 of the prior art; the cell edge throughput of the present invention is 0.0142, which is also greater than 0.0126 of the prior art . Therefore, the method of the present invention significantly improves the cell average throughput and the cell edge throughput.

Table 2 System simulation results

FIG. 11 shows a comparison of simulation results according to the method shown in FIG. 6 and the prior art.

The two curves shown in FIG. 11 are the normalized user throughput of the method of the present invention and the prior art respectively. Table 3 shows the corresponding system simulation results, showing the corresponding user average and user edge (5%) user throughput and its gain. It can be seen that, compared with the performance of a traditional cellular system without frequency reuse, the frequency reuse method of the present invention can simultaneously improve cell edge performance and overall system performance.

Table 3 System simulation results

It should be noted that the disclosed method of the present invention can be implemented in software, hardware, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in memory and executed by a suitable instruction execution system such as a microprocessor, personal computer (PC) or mainframe.

The description of the present invention has been presented for purposes of illustration and description, not exhaustive or limited to the invention in the form disclosed. Many modifications and changes will be apparent to those of ordinary skill in the art.

Therefore, the embodiment is selected and described in order to better explain the principle of the present invention and its practical application, and to make those skilled in the art understand that all modifications and changes fall within the scope of the patent rights without departing from the essence of the present invention. within the scope of protection of the present invention as defined by the requirements.

Claims (19)

1., for a frequency reuse approach for heterogeneous network, described method comprises step:

Determine the neighbor cell of current area;

Receive the information relevant to the edge band of neighbor cell;

Based on received information, micro-base station of current area is made to reuse the edge band of described neighbor cell.

2. method according to claim 1, the step wherein making micro-base station of current area reuse the edge band of described neighbor cell comprises:

Determine the summation of the edge band of each neighbor cell; And

Each micro-base station of current area is made to reuse the summation of described edge band.

3. method according to claim 1, the step wherein making micro-base station of current area reuse the edge band of described neighbor cell comprises:

Determine to disturb maximum neighbor cell to each micro-base station of current area;

Each micro-base station described is made to reuse the edge band of the neighbor cell except disturbing maximum neighbor cell.

4. method according to claim 3, wherein determine to disturb the step of maximum neighbor cell to comprise to each micro-base station of current area:

Obtain the sector antenna beam direction of the macro base station of neighbor cell;

Determine the angle between the line direction of a micro-base station of current area and the macro base station of described neighbor cell and the sector antenna beam direction obtained;

Each angle determined is sorted;

The neighbor cell corresponding with minimum angle is defined as disturb maximum neighbor cell to described micro-base station.

5. method according to claim 3, wherein determine to disturb the step of maximum neighbor cell to comprise to each micro-base station of current area:

The power of the signal that the micro-base station obtaining current area receives from the macro base station of neighbor cell;

Sort according to the power of obtained signal;

The neighbor cell corresponding with the signal of maximum power is defined as disturb maximum neighbor cell to described micro-base station.

6. method according to claim 1, the reference signal power size that the subscriber equipment of wherein directly serving according to macro base station receives from described macro base station is described user equipment allocation resource.

7. method according to claim 6, wherein said macro base station is the user equipment allocation edge band that the reference signal power received is less than predetermined power threshold, for the reference signal power received is more than or equal to the user equipment allocation center frequency-band of predetermined power threshold.

8. method according to claim 6, wherein corresponding with the edge band of community power is higher than the power corresponding with the center frequency-band of described community.

9. method according to claim 1, wherein the frequency of the frequency of the edge band of current area and the edge band of neighbor cell is mutually orthogonal.

10., for a frequency reuse equipment for heterogeneous network, described equipment comprises:

Determining unit, for determining the neighbor cell of current area;

Receiving element, for receiving the information relevant to the edge band of neighbor cell;

Reuse unit, the information for receiving based on described receiving element makes micro-base station of current area reuse the edge band of described neighbor cell.

11. equipment according to claim 10, wherein said unit of reusing comprises:

Determining device, for determining the summation of the edge band of each neighbor cell; And

Reuse device, for the summation making each micro-base station of current area reuse described edge band.

12. equipment according to claim 10, wherein said unit of reusing comprises:

Determining device, disturbs maximum neighbor cell for determining to each micro-base station of current area;

Reuse device, reuses the edge band of the neighbor cell except disturbing maximum neighbor cell for making each micro-base station described.

13. equipment according to claim 12, wherein said determining device comprises:

For obtaining the device in the sector antenna beam direction of the macro base station of neighbor cell;

For the device of the angle between the line direction of the macro base station of a micro-base station and described neighbor cell of determining current area and the sector antenna beam direction obtained;

For the device sorted to each angle determined;

For the neighbor cell corresponding with minimum angle being defined as the device described micro-base station being disturbed to maximum neighbor cell.

14. equipment according to claim 12, wherein said determining device comprises:

The device of the power of the signal received from the macro base station of neighbor cell for the micro-base station obtaining current area;

For the device that basis sorts to the power of obtained signal;

For the neighbor cell corresponding with the signal of maximum power being defined as the device described micro-base station being disturbed to maximum neighbor cell.

15. equipment according to claim 10, wherein in described heterogeneous network, the reference signal power size that the subscriber equipment of directly serving according to macro base station receives from described macro base station is described user equipment allocation resource.

16. equipment according to claim 15, wherein said macro base station is the user equipment allocation edge band that the reference signal power received is less than predetermined power threshold, for the reference signal power received is more than or equal to the user equipment allocation center frequency-band of predetermined power threshold.

17. equipment according to claim 15, wherein corresponding with the edge band of community power is higher than the power corresponding with the center frequency-band of described community.

18. equipment according to claim 10, wherein in described heterogeneous network, the frequency of the frequency of the edge band of current area and the edge band of neighbor cell is mutually orthogonal.

19. 1 kinds of nodes, comprising: the equipment according to any one of claim 10-18.