WO2011124026A1

WO2011124026A1 - Frequency reuse method and device

Info

Publication number: WO2011124026A1
Application number: PCT/CN2010/071608
Authority: WO
Inventors: 刘建国; 王栋耀; 庞继勇; 沈钢; 蒋琦; 王钧
Original assignee: 上海贝尔股份有限公司; 阿尔卡特朗讯
Priority date: 2010-04-07
Filing date: 2010-04-07
Publication date: 2011-10-13
Also published as: CN102726084A; CN102726084B

Abstract

A frequency reuse method for a heterogeneous network and a device thereof are disclosed. The method includes steps of: determining an adjacent cell of a current cell; receiving information associated with the edge frequency band of the adjacent cell; and enabling the micro base station of the current cell to reuse the edge frequency band of the adjacent cell based on the received information. The method can apparently reduce inter-cell interference and improve throughput of a user equipment.

Description

Frequency reuse method and equipment

The present invention relates generally to frequency reuse techniques, and more particularly to a frequency reuse method and apparatus for improving reception performance of cell edge user equipment by inter-cell interference coordination in a heterogeneous wireless communication system. Background technique

In a multi-cell wireless communication network, inter-cell interference is caused when neighboring cells allocate the same frequency band to each user equipment. At present, the three main ways to mitigate inter-cell interference are: interference randomization, small-area interference cancellation, and inter-cell interference coordination (ICIC). 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 considered the most promising way and is already in 3GPP ( The third generation partnership program) has been extensively studied in LTE (Long Term Evolution).

The ICIC solution achieves better reuse by coordinating frequency and power allocation for better network performance. Most ICIC schemes are based on the principle of fractional frequency reuse (FFR). The principle of FFR is to use different frequency reuse factors depending on the channel conditions and interference conditions 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 control for different subcarrier groups for inter-cell coordination.

As the demand for data services increases, heterogeneous networks (HetNet) are an effective method to improve system capacity and coverage, and have been added to 3GPP LTE-Advanced as a research project. Heterogeneous networks usually have many low-power nodes (abbreviated as LPN), such as pico, hotzone, femto, and relay nodes (abbreviated as RN). Compared with homogeneous networks, the inter-cell interference situation of heterogeneous networks is more serious. However, there are currently few documents related to such as 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. Summary of the invention

In response to the above problems, the present invention provides a frequency reuse method and apparatus in a heterogeneous wireless communication system for mitigating inter-cell interference in a heterogeneous network.

According to a first aspect of the present invention, a frequency reuse method for a heterogeneous network is provided, comprising the steps of: determining a neighboring cell of a current cell; receiving information related to an edge band of a neighboring cell; based on the received information And causing the micro base station of the current cell to reuse the edge frequency band of the neighboring cell.

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

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

Other objects and effects of the present invention will become more apparent and appreciated from the following description of the embodiments of the invention.

Figure 1 shows an exemplary heterogeneous network;

2 is a block diagram of a frequency reuse device for a heterogeneous network, in accordance with one embodiment of the present invention;

3 is a flow chart of a frequency reuse method for a heterogeneous network, in accordance with one 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 flow chart of a frequency reuse method for a heterogeneous network according to another embodiment of the present invention;

7 is a flow diagram of a method for determining a neighboring cell having the greatest interference to a micro-base station of a current cell, in accordance with an embodiment of the present invention;

8 is a flow chart of a method for determining a neighboring cell having the greatest interference to a micro base station of a current cell according to another embodiment of the present invention;

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

Figure 9B shows the band reuse result according to the method shown in Figure 5;

Figure 9C shows the band reuse result according to the method shown in Figure 6;

Figure 10 shows a comparison of simulation results with the prior art according to the method shown in Figure 5;

Fig. 11 shows a comparison of the simulation results with the prior art according to the method shown in Fig. 6. In all of the above figures, the same reference numerals indicate the same or similar features or functions. Specific embodiment

The invention will be explained and illustrated in more detail below with reference to the accompanying drawings. The drawings and embodiments of the present invention are to be considered as illustrative only and not limiting the scope of the invention.

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

In the present invention, the spectrum resource is allocated to the user equipment according to the power of the reference signal received by the user equipment directly served by the macro base station from the macro base station. Specifically, the macro base station may send a reference signal to the user equipment directly served by the macro base station in the cell. For example, if the user equipment receives a large signal power from the macro base station, for example, greater than a predetermined power threshold, the user equipment may be considered as the user equipment. An internal area that is in the coverage of the macro base station, The user equipment can then be classified into a cell center user, and the frequency band used for communication between the user equipment and the macro base station is referred to as a center 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, the user equipment may be considered to be in an edge area of the coverage of the macro base station, and then the user equipment may be classified as a cell edge user, and The frequency band used for communication between the user equipment and the macro base station is referred to as an edge frequency band. That is, the macro base station allocates an edge frequency band for the user equipment whose received reference signal power is less than the predetermined power threshold, and allocates the center frequency band for the user equipment whose received reference signal power is greater than or equal to the predetermined power threshold.

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

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

Currently, heterogeneous networks typically have a number of lower-power nodes (called LPNs) (e.g., ico, hotzone, femto, and relay stations, etc.), which are referred to herein as micro-base stations. In a specific implementation, the micro base station may be a low-power node directly connected to the core network; or may be used as a relay node, relaying communication of its user terminal to the macro base station, and implementing communication between the user terminal of the LPN and the macro base station.

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

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

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

In the heterogeneous network of Figure 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. 9A is a schematic diagram showing frequency and power management of a macro base station having three sectors (corresponding to cells 0A, 0B, 0C) in FIG. 1, wherein an edge band 901 of a cell OA corresponds to F1, and a center band 902 includes F2 and F3; The edge band 903 of cell 0B corresponds to F2, the center band 904 includes F1 and F3; the edge band 905 of cell 0C corresponds to F3, and the center 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, such as LPN1 and LPN2 located at the cell edge in the heterogeneous network shown in Fig. 1. The receive/transmit antennas of the LPN and user equipment can be omnidirectional.

It is to be understood that the above-mentioned assumptions and limitations of the invention are merely illustrative and are not to be construed as limiting.

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

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

3 is a frequency reuse method for a heterogeneous network according to an embodiment of the present invention. Flow chart. It is to be noted that the various steps shown in FIG. 3 can be performed separately by the corresponding devices shown in FIG. 2.

In step 301, a neighboring cell of the current cell is determined.

In this embodiment, the cell OA in Fig. 1 is taken as the current cell, so the neighbor cell of the cell OA is determined in step 301. It can be determined from Fig. 1 that the neighboring cells of the cell OA are cells 0B, 0C, 6B, 1C, 1B, 2C:.

At step 302, information related to an edge band of a neighboring cell is received.

The information related to the edge band of the neighboring cell may include, for example, an identifier of the neighboring cell, a location of the macro base station of the neighboring cell, a frequency range or a frequency band of the edge band of the neighboring cell (eg, including a starting frequency, an ending frequency, for example) , bandwidth, etc.) and corresponding power levels, and so on.

In the present invention, information related to the edge band of the neighboring cell may be stored in a memory in the frequency reuse device shown in FIG. 2, or any one stored in the network may be accessed by the frequency reuse device shown in FIG. In a storage device or any other device.

In this step, the frequency reuse device of the present invention receives the neighboring cell 0B,

Edge band related information of 0C, 6B, 1C 1B, 2C.

In step 303, based on the received information, the micro base station of the current cell reuses the edge frequency band of the neighboring cell.

The flow shown in Figures 5 and 6 gives two specific implementations of implementation step 303, which are described in detail below.

Then, the flow of Figure 3 ends.

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

In one embodiment, the determining means 431 is configured to determine a sum of edge bands of respective neighboring cells, and the reusing means 432 is configured to reuse each of the micro-base stations of the current cell. The sum of the edge bands. Fig. 5 shows a flow chart of a method corresponding to this embodiment. In another embodiment, the determining means 43 1 is configured to determine a neighboring cell that has the greatest interference to the respective micro base stations of the current cell; the reusing means 432 is configured to reuse the each of the micro base stations by the neighboring cell except the one having the largest interference The edge band of the neighboring cell. Figure 6 shows a flow chart of the method corresponding to this embodiment.

In a specific implementation as an example, the determining apparatus 431 may further include: means for acquiring a sector antenna beam direction of the macro base station of the neighboring cell; a micro base station for determining the current cell and the Means for arranging the angle between the connection direction of the macro base station of the neighboring cell and the acquired sector antenna beam direction; means for ordering the determined angles; for matching the minimum angle The neighboring cell is determined as a device of the neighboring cell that has the greatest interference to the micro base station. Figure 7 shows a flow chart of the method corresponding to this implementation.

In another specific implementation example, the determining apparatus 43 1 may further include: means for acquiring power of a signal received by a micro base station of the current cell from a macro base station of the neighboring cell; Means for ordering the power of the acquired signal; means for determining a neighboring cell corresponding to the signal of the maximum power as a neighboring cell having the greatest interference with the micro base station. Figure 8 shows a flow chart of the method corresponding to this implementation.

Figure 5 is a flow diagram of a frequency reuse method for a heterogeneous network in accordance with another embodiment of the present invention.

In step 501, a neighboring cell of the current cell is determined.

This step is similar to the foregoing step 301. In the embodiment, the cell OA in FIG. 1 is also used as the current cell, and then the neighboring cell of the current cell OA is determined to be the cell 0B, 0C, 6B, 1 C, 1 B, 2C. .

At step 502, information related to an edge band of a neighboring cell is received.

Similar to the foregoing step 302, in the present embodiment, the frequency reuse device also receives information related to the edge bands of the neighboring cells 0B, 0C, 6B, 1 C, 1 B, 2C. For example, the identifier of the neighboring cell is CELL _OB

CELL ₆ B CEI _{1 C} , CELL _1B CELL _2C ; the location of the macro base station eNB l , eNB 2 , eNB 6 of the neighboring cell; As shown, the frequency range of the edge band of the adjacent cells 0B, 6B, IB is F2 and the corresponding power level is _α , and the frequency range of the edge band of the adjacent cells 0C, 1C, 2C is F3 and the corresponding power level is also . It should be noted that the present invention does not limit that the edge bands of adjacent cells need to have the same power level as long as the transmit power of the edge band of each cell is higher than the transmit power of the center band.

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

At step 503, the sum of the edge bands of the respective neighboring cells is determined.

According to step 502, the frequency range of the edge band of the neighboring cells 0B, 6B, and IB is F2, and the frequency range of the edge band of the neighboring cells 0C, 1 C, and 2C is F3, so that neighboring cells 0B, 0C, The sum of the edge bands of 6B, 1C, 1B, 2C is the frequency range composed of F2 and F3.

At step 504, each micro base station of the current cell reuses the sum of the edge bands. Then, the flow of Figure 5 ends.

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

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

When the cell 0C is the current cell, the micro base stations LPN1 and LPN2 in the cell 0B reuse the 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 OA, the user equipments of the micro base stations LPN1 and LPN2 of the cell OA can be effectively avoided. Interference with the edge band from the own cell (i.e., cell OA). In addition, since the cell base station is reduced in its frequency bands F2 and F3 The transmission power can therefore effectively reduce the interference of the respective user equipments of the micro base stations LPN1 and LPN2 with the central frequency band from the own cell (i.e., the cell OA).

Furthermore, it should be noted that although the micro base station reuses the edge frequency range of the neighboring 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 neighboring cell.

6 is a flow chart of a frequency reuse method for a heterogeneous network in accordance with another embodiment of the present invention.

In step 601, a neighboring cell of the current cell is determined.

This step is similar to the foregoing step 301 and step 501. In the embodiment, the cell OA in FIG. 1 is also used as the current cell, and the neighboring cell of the current cell OA is determined to be the cell 0B, 0C, 6B, 1C, 1B, 2C.

At step 602, information related to an edge band of a neighboring cell is received.

Similar to step 502, in the present embodiment, the frequency reuse device also receives information related to the edge bands of the neighboring cells 0B, 0C, 6B, 1C, 1B, 2C. For example, the identifiers of the neighboring cells are CEI _0B , CELLoc^CELL _6B CELL _1C > CEIX _1B , CELL _2C ; the locations of the macro base stations eNB1, eNB2, and eNB6 of the neighboring cells; as shown in FIG. 9A, the neighboring cell 0B, 6B. The frequency range of the edge band of IB is F2 and the corresponding power level is that the frequency range of the edge band of the adjacent cell 0C, 1C:, 2C is F3 and the corresponding power level is also ". It should be noted that the present invention does not limit that the edge bands of adjacent cells need to have the same power level as long as the transmit power of the edge band of each cell is higher than the transmit power of the center band.

At step 603, a neighboring cell having the greatest interference to each of the micro-base stations of the current cell is determined. Two exemplary specific implementations for implementing step 603 are shown in FIGS. 7 and 8. 7 is a flow diagram of a method for determining a neighboring cell that has the greatest interference to a micro-base station of a current cell, in accordance with an embodiment of the present invention.

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

The sector antenna beam direction of the macro base station of each cell may be stored in a highly functional macro base station in the entire network system, or may be stored in a macro base station of each cell, so the frequency reuse device of the present invention may perform the above functions. Strong macro base station or The macro base station of each cell acquires 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 transmitting 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 of the neighboring cell can be expressed, for example, as the angle between the antenna beam direction and the horizontal plane.

In step 702, an angle between a connection direction of a micro base station of the current cell and an a macro base station of the neighboring cell and an acquired sector antenna beam direction is determined.

Based on the information related to the edge band of the neighboring cell received at step 502, the locations of the macro base stations eNB 1, eNB 2, and eNB 6 of the neighboring cells can be known.

First, in step 702, the location of the micro base station LPN1 of the current cell OA is determined, and then three connections may be obtained according to the location of the LPN1 and the locations of the macro base stations eNB1, eNB2, and eNB6, and then the neighboring cells that may be acquired from step 701 may be obtained. The sector antenna beam direction of the macro base station is used to select the sector antenna beam direction of the macro base stations eNB1, eNB2, and eNB6, and then the connection direction of the three antennas associated with the macro base stations eNB1, eNB2, and eNB6 can be utilized and associated with the macro base stations eNB1, eNB2. The 9 sector antenna beam directions of eNB6 (since one macro base station has 3 antennas, the three macro base stations eNB1, eNB2, and eNB6 share 9 sector antenna beam directions) to calculate 9 angles. For example, three angles can be calculated between the connection direction of the macro base station eNB1 and the LPN1 of the cell OA and the three antenna beam directions of the macro base station eNB1, and so on, for the LPN1, the macro base station eNB2 and the eNB6 are also respectively different. Three angles can be calculated to obtain nine angles.

Similarly, the other three connections can be obtained according to the location of the LPN2 and the locations of the macro base stations eNB1, eNB2, and eNB 6, and then the nine antennas are used to calculate the beam direction of the nine sector antennas of the macro base station eNB1, eNB2, and eNB6. An angle.

At step 703, the determined individual angles are sorted.

The sorting operation is performed separately for the micro base station LPN1 of the current cell OA, that is, the calculated nine angles associated with the LPN1 are sorted.

In addition, the micro-base station LPN2 for the current cell OA also performs the sorting operation separately, that is, sorts the calculated nine angles associated with the LPN2.

At step 704, determining a neighboring cell corresponding to the smallest angle as the pair of micro base stations The neighboring cell with the largest interference.

In this embodiment, it is assumed that the minimum angle of the micro base station LPN1 for the current cell OA is the sector antenna beam direction of the macro base station eNB6 in the cell 6B, so the neighboring cell 6B is determined to interfere with the micro base station LPN1 in step 704. The largest neighboring cell.

It is assumed that the minimum angle of the micro base station LPN2 for the current cell OA is the sector antenna beam direction of the macro base station eNB2 in the cell 2C, and therefore the neighboring cell 2C is determined as the neighboring cell having the greatest interference to the micro base station LPN2.

Then, the flow of Figure 7 ends.

Figure 8 is a flow diagram of a method for determining a neighboring cell having the greatest interference to a micro base station of a current cell, in accordance with another embodiment of the present invention.

In step 801, the power of the signal received by the t base station of the current cell from the macro base station of the neighboring cell is obtained.

For example, by measuring the power of the signals received by the micro-base station LPN1 of the current cell OA from the neighboring cells 0B, 0C, 6B, 1 :, 1 B, 2C, six signal power values can be obtained. Six signal power values can also be obtained by measuring the power of the signals received by the microcells LPN2 of the current cell OA from the neighboring cells 0B, 0C, 6B 1 C, 1 B, 2C, respectively.

At step 802, the power of the acquired signals is ordered.

In this step, a sort operation is performed on the six signal power values associated with LPN1 and the six signal power values associated with LPN2, respectively.

In step 803, the neighboring cell corresponding to the signal of the maximum power is determined as the neighboring cell having the greatest interference to the micro base station.

It is assumed that the maximum signal power received by the micro base station LPN1 of the current cell 0A is the 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 the signal from the macro base station eNB2, then in step 803 The neighboring cell 6B determines the neighboring cell that has the greatest interference to the micro base station LPN1 and determines the neighboring cell 2C as the neighboring cell that has the greatest interference to the micro base station LPN2.

Then, the flow of Figure 8 ends.

At step 604, the each micro base station is reused except for the neighboring cell with the largest interference. The edge band of the neighboring cell.

For the micro base station LPN1 of the current cell OA, since the neighboring cell with the largest interference determined in the example of step 603 is 6B, and the edge band of the cell 6B corresponds to F2, the LPN1 reuses the frequency band other than the F2. The edge band of the neighboring cell. Since the edge band of the neighboring cell of the current cell OA is F2 or F3, the LPN1 reuses the frequency band F3 other than F2.

For the micro base station LPN2 of the current cell OA, since the neighboring cell with the largest interference determined in the example of step 603 is 2C, and the edge band of the cell 2C corresponds to F3, the LPN2 reuses the frequency band other than the F3. The edge band of the neighboring cell. Since the edge band of the neighboring cell of the current cell OA is F2 or F3, the LPN2 reuses the frequency band F2 other than F3.

Then, the flow of Figure 6 ends.

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

In addition, when the cell 0B is 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 of 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 of the cell 0C reuses the frequency band F1 to serve its user equipment.

With this frequency reuse method, in addition to mitigating interference between the user equipment of the base station and the own cell, it is also possible to remove primary interference from neighboring cells.

For the above radio resource management scheme, the cell edge user equipment mainly interferes with the central frequency band from the neighboring cell. Since the transmit power of the neighboring cell base station and the micro base station occupying the center band is much lower than the transmit power of the cell edge band, the cell edge user equipment reception performance can be greatly improved. On the other hand, for a micro base station deployed at the edge, the primary interference of its user equipment comes from the central frequency band of the own cell and the adjacent cell edge frequency band. The reduced transmission power and the phase of the base station of the cell in the central frequency band The neighboring base station is far away from the user equipment of the micro base station of the cell, so the user equipment of the micro base station is less interfered. In particular, when the micro base station shows the spectrum reuse method using FIG. 9C, the inter-cell interference from the neighboring cell of the user equipment of the micro base station will be further reduced. For a central user equipment served by a macro base station, the frequency reuse scheme has less impact on its performance due to its proximity to the serving base station.

Figures 10 and 11 respectively show a comparison of the frequency reuse method according to the present invention with the simulation results of 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 of the method of Fig. 5 of the present invention with the prior art. In FIG. 11, the micro base stations are, for example, in-band relay nodes, and the user equipment of the micro base station communicates with the macro base station via a micro base station as a repeater, and FIG. 11 is for the present invention. The method shown in Figure 6 is compared to the prior art.

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

Table 1 system level simulation parameters

Scheduling

Downlink HARQ has CC (Chasing Combing, Chase merge) asynchronous HARQ, maximum triple retransmission, and hop-by-hop HARQ in the relay network

Channel Model High Frequency SCM Channel Model for 3GPPCasel Macrocell

Base station eNodeB antenna configuration 1 transmit antenna with antenna mode defined in 3GPP TS 36.814 VL6.2

Low power node LNP antenna with 1 transmit antenna (for Pico nodes and relay nodes) and 2 receive antennas (for relay nodes) with antenna placement mode defined in 3GPP TS 36.814 VI.6.2 User terminal UE antenna configuration 2 receiving antennas (0 dBi antenna gain, omnidirectional) Downstream receiver type MRC (maximum ratio combining)

Path loss model with 3GPP TS 36.814 VI.6.2

Traffic Model Fully Buffer Full Buffer

Control channel overhead, ACK, etc. LTE: L = 3 symbols or DL CCH, for the overhead of the demodulation reference signal Figure 10 shows a comparison of the simulation results according to the method shown in Figure 5 with the prior art. In a multi-user system, the effects of the technical solution can be compared by considering the fairness between users. For example, a Cumulative Distribution Function (CDF) curve of normalized user throughput can be used to represent this effect. Throughput is typically expressed in terms of the amount of data that is correctly transmitted per unit of time, normalizing the throughput of all users relative to the system bandwidth. User throughput. Table 2 shows the corresponding system simulation results, representing the corresponding user average and user edge (5%) throughput and its gain. It can be seen that the average cell throughput of the present invention is 2.06, which is greater than 1.93 of the prior art, compared with the performance of the frequency reuse heterogeneous system. The cell edge throughput of the present invention is 0.0142, which is also larger than the prior art 0.0126. . Therefore, the method of the present invention significantly improves the average cell throughput and cell edge Throughput. Table 2 system simulation

Figure 11 shows a comparison of the simulation results of the method according to Figure 6 with the prior art. The two curves shown in Figure 11 are the method of the present invention and the normalized user throughput of the prior art, respectively. Table 3 shows the corresponding system simulation results, representing the corresponding user average and user edge (5 %) user throughput and its gain. It can be seen that the frequency reuse method of the present invention can simultaneously improve cell edge performance and overall system performance as compared to the performance of conventional cellular system without frequency reuse. Table 3 System simulation

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 portion can be implemented using dedicated logic; the software portion 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 is intended to be illustrative, and not restrictive or limiting. Many modifications and variations will be apparent to those skilled in the art.

Therefore, the embodiments were chosen and described in order to explain the embodiments of the invention and the embodiments of the invention It is intended to be within the scope of the invention as defined.

Claims

Claim

A frequency reuse method for a heterogeneous network, the method comprising the steps of: determining a neighboring cell of a current cell;

Receiving information related to an edge band of a neighboring cell;

Based on the received information, the micro base station of the current cell reuses the edge band of the neighboring cell.

2. The method according to claim 1, wherein the step of reusing the edge frequency band of the neighboring cell by the micro base station of the current cell comprises:

Determining the sum of the edge bands of each neighboring cell;

The sum of the edge bands is reused by each micro base station of the current cell.

3. The method according to claim 1, wherein the step of reusing the edge frequency band of the neighboring cell by the micro base station of the current cell comprises:

Determining a neighboring cell that has the greatest interference to each micro base station of the current cell;

Each of the micro base stations is caused to reuse an edge band of a neighboring cell other than the neighboring cell having the largest interference.

4. The method according to claim 3, wherein the step of determining a neighboring cell that has the greatest interference to each of the micro-base stations of the current cell comprises:

Obtaining a sector antenna beam direction of a macro base station of a neighboring cell;

Determining an angle between a connection direction of a micro base station of the current cell and a macro base station of the neighboring cell and a direction of the acquired sector antenna beam;

Sorting the determined angles;

The neighboring cell corresponding to the smallest angle is determined as the neighboring cell having the greatest interference to the micro base station.

5. The method according to claim 3, wherein the step of determining a neighboring cell that has the greatest interference to each of the micro-base stations of the current cell comprises:

Obtaining the power of a signal received by a micro base station of the current cell from a macro base station of the neighboring cell;

Sorting the power of the acquired signals; The neighboring cell corresponding to the signal of the maximum power is determined as the neighboring cell that has the greatest interference to the micro base station.

The method according to claim 1, wherein the user equipment is allocated resources according to a reference signal power size received by the user equipment directly served by the macro base station from the macro base station.

The method according to claim 6, wherein the macro base station allocates an edge frequency band for a user equipment whose received reference signal power is less than a predetermined power threshold, and allocates a center for a user equipment whose received reference signal power is greater than or equal to a predetermined power threshold. frequency band.

8. The method of claim 6, wherein the power corresponding to an edge band of a cell is higher than the power corresponding to a center band of the cell.

9. The method of claim 1, wherein a frequency of an edge band of a current cell and a frequency of an edge band of a neighboring cell are orthogonal to each other.

10. A frequency reuse device for a heterogeneous network, the device comprising: a determining unit, configured to determine a neighboring cell of a current cell;

And a receiving unit, configured to receive information related to an edge frequency band of the neighboring cell, and a reusing unit, configured to enable the micro base station of the current cell to reuse an edge frequency band of the neighboring cell based on the information received by the receiving unit.

1 1. The apparatus according to claim 10, wherein the reusing unit comprises: determining means for determining a sum of edge bands of respective neighboring cells; and means for reusing each micro base station of the current cell The sum of the edge bands.

The device according to claim 10, wherein the reusing unit comprises: determining means for determining a neighboring cell that has the greatest interference to each micro base station of the current cell;

And a reusing device, configured to enable each of the micro base stations to reuse an edge frequency band of a neighboring cell other than the neighboring cell with the largest interference.

13. The apparatus according to claim 12, wherein the determining means comprises: means for acquiring a sector antenna beam direction of a macro base station of a neighboring cell; a micro base station for determining a current cell and the neighboring The macro base station of the cell Means for the angle between the line direction and the acquired sector antenna beam direction; means for ordering the determined individual angles;

A means for determining a neighboring cell corresponding to the smallest angle as a neighboring cell having the greatest interference with the micro base station.

14. The apparatus according to claim 12, wherein the determining means comprises: means for acquiring power of a signal received by a micro base station of a current cell from a macro base station of a neighboring cell;

Means for sorting based on the power of the acquired signals;

A neighboring cell for determining a signal corresponding to the signal of the maximum power is a device of a neighboring cell having the greatest interference with the micro base station.

The device according to claim 10, wherein in the heterogeneous network, resources are allocated to the user equipment according to a reference signal power size received by the user equipment directly served by the macro base station from the macro base station.

16. The apparatus according to claim 15, wherein the macro base station allocates an edge frequency band to a user equipment whose received reference signal power is less than a predetermined power threshold, and is a user equipment allocation center whose received reference signal power is greater than or equal to a predetermined power threshold. frequency band.

17. The apparatus of claim 15, wherein a power corresponding to an edge band of a cell is higher than a power corresponding to a center band of the cell.

18. The apparatus according to claim 10, wherein in the heterogeneous network, a frequency of an edge band of a current cell and a frequency of an edge band of a neighboring cell are orthogonal to each other.

19. A node comprising: the apparatus of any of claims 10-18.