CN101335539B - Cochannel interference suppressing method between users and base station thereof - Google Patents

Abstract

The invention relates to a method for suppressing co-channel interference between users in the technical field of communication and a base station thereof. The steps are: the user monitors and detects the downlink signals of the own cell or sector and a plurality of adjacent cells or sectors; or the geographical location information in the sector to make a judgment, and obtain the geographical location information of the user in the cell or sector; the base stations of adjacent cells or sectors share resources with the border users of this cell or sector Notify the base station of the adjacent cell or sector; perform inter-cell or sector communication on the resource occupied by the border user according to the allocation result, if the border user of the adjacent cell uses the same resource, re-allocate the resource; the base station according to the resource allocation result, Adapt the user's uplink. When realizing the goal of reducing co-channel interference among users, the present invention has the advantages of high frequency spectrum reuse coefficient, increased output rate of border users, and the like.

Description

Method for suppressing co-channel interference between users and its base station

technical field

The invention relates to an identification method in the field of communication technology and a base station thereof, in particular to a method for suppressing co-channel interference between users of an uplink FDD-FDMA cellular system and a base station thereof.

Background technique

The FDD (Frequency Division Duplex) method is the main duplex method adopted by the cellular system, and its technical feature is that the uplink communication link and the downlink communication link use different frequency bands. In the FDD system, FDMA (Frequency Division Multiple Access) is the most important multiple access method, and its characteristic is that different users use different spectrum resources when accessing the system. At present, OFDM (Orthogonal Frequency Division Multiplexing) technology and SC-OFDM (Single Carrier Orthogonal Frequency Division Multiplexing) technology are the main technologies for realizing FDD-FDMA. The 3GPP organization (Third Generation Mobile Communications Partnership Project) international organization is designing EUTRA (Evolved Universal Mobile Telecommunications System and Terrestrial Radio Access) and EUTRAN (Evolved Universal Mobile Telecommunications System Network and Terrestrial Radio Access Network) (or When it is called Super 3G (super three-generation mobile communication system), it uses SC-OFDM technology to realize the uplink FDD-FDMA cellular system.

Generally, the cellular system divides the service coverage area into several regular hexagonal cells, and each cell is generally divided into 3 sectors or 6 sectors equally. In an uplink FDD-FDMA cellular system, a cell or sector base station allocates uplink resources (hereinafter referred to as resources) and uplink power to users. The resources include time slot resources, spectrum resources, and possibly codeword resources, etc. In an actual system, since the entire frequency spectrum is reused by all cells or sectors, when two users in two adjacent cells or sectors are allocated the same resources, co-channel interference will occur between these two users. This interference is particularly significant when the above two users are located at cell or sector boundaries. Therefore, corresponding methods need to be designed to reduce co-channel interference among users.

In the prior art literature, for the uplink FDD-FDMA cellular system required by EUTRA, there are four methods that can be used to reduce co-channel interference between users:

(1) A simple method for coordinating or avoiding interference between cells or sectors: each cell or sector allocates specific resources for its boundary users, called "boundary user dedicated resources", and guarantees There is no overlapping of user-dedicated resources at the border of the cell or sector, thereby avoiding severe co-channel interference among users at the cell or sector border. The border user-dedicated resources cannot be reused by adjacent cells or sectors, so its spectrum reuse coefficient is greatly reduced, resulting in a significant decrease in the overall data transmission rate of the system. Such as the prior art publication: patent name "Subcarrier Allocation Method for Reducing Inter-cell Interference in Orthogonal Frequency Division Multiplexing Cellular Environment", application (patent) number: 200480006260.4, publication (announcement) number: CN1759582)

(2) A method for coordinating or avoiding inter-cell interference with higher spectrum reuse coefficients: each cell divides border user-specific resources for border users therein, and ensures that border user-dedicated resources between adjacent cells do not overlap, In this way, severe co-channel interference among users at the cell boundary is avoided. The border user dedicated resource can be reused by non-border users in adjacent cells, so its frequency spectrum reuse coefficient is relatively high. Such as prior art publications: 3GPP, R1-050629, "Inter-cell interference mitigation", Huawei. (3GPP document, number: R1-050629, "Inter-cell interference suppression method", Huawei)

(3) The method of inter-cell interference elimination: using multi-user detection technology, the co-channel interference signal is first demodulated and decoded, then the interference signal is reconstructed, and then the reconstructed interference signal is subtracted from the received signal, and finally the useful signal is obtained. Thereby eliminating co-channel interference among users. Such as prior art publications: 3GPP, R1-060418, "TP on uplink inter-cell interference cancellation", RITT, Huawei, CATT. (3GPP document, number: R1-060418, "Inter-cell interference cancellation method and standardization text proposal", RITT company, Huawei company, CATT company)

(4) A method combining inter-cell interference coordination/avoidance and interference cancellation: the entire resource is divided into resources applicable to interference coordination or avoidance and resources applicable to interference cancellation without intersection, and for resources applicable to interference coordination or avoidance, the method (2) Reduce the co-channel interference between users; for resources applicable to interference cancellation, adopt the method (3) to reduce the co-channel interference between users. Such as the prior art publications: 3GPP, R1-060419, "Combining Inter-cell-interference co-ordination/avoidance with cancellation in uplink and TP", RITT, Huawei, CATT. (3GPP document, No.: R1-060419, "A method for combining inter-cell interference coordination/avoidance with interference cancellation and standardization text proposal", RITT, Huawei, CATT)

Method (1) has the disadvantage of low spectrum reuse coefficient; method (2) maintains the advantages of method (1) and has a high spectrum reuse coefficient, but when allocating resources for border users, due to optional The resource is severely limited, which will lead to a large decrease in the efficiency of resource scheduling, so that the total data transmission rate of the system will be greatly reduced; method (3) overcomes the shortcomings of method (2), and also has higher spectrum reuse coefficient, but it requires a large computational overhead for the reconstruction and elimination of interference signals, or a certain amount of inter-cell coordination is required to establish interference user pairs to simplify calculations; method (4) combines method (2) and method (3) , but it is necessary to divide the resources applicable to interference coordination or avoidance and the resources applicable to interference cancellation, and use different methods to reduce co-channel interference between users, which increases the complexity of the entire solution. In addition, in order to ensure that the method The adaptability of the system also needs to increase the signaling interaction between the user and the base station. Therefore, the above four methods encounter great difficulties in practical application.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, to provide a method for suppressing co-channel interference between users and its base station, so that it can solve the problem that the spectrum reuse coefficient is low, or the implementation complexity is high, or the user and The problem of many signaling interactions between base stations. The present invention is a method for inter-cell or inter-sector interference coordination or avoidance through inter-cell communication. After the cell or sector allocates resources to users each time, inter-cell communication is performed to observe border users of adjacent cells or sectors. Whether to allocate the same resources to avoid co-channel interference caused by border users using the same resources.

The present invention is realized through the following technical solutions,

The method for suppressing co-channel interference between users involved in the present invention comprises the following steps:

Step 1: The user monitors and detects the downlink signals of the cell or sector and multiple neighboring cells or sectors;

Step 2: According to the downlink signal strength of the cell or sector and multiple adjacent cells or sectors, make a judgment on the geographical location information of the user in the cell or sector, and obtain the geographic location of the user in the cell or sector location information;

Step 3: the base stations of the adjacent cells or sectors notify the base stations of the adjacent cells or sectors of the resources occupied by the border users of this cell or sector;

Step 4: According to the allocation result, perform inter-cell or inter-sector communication on the resources occupied by the border users, and re-allocate the resources if it is found that the border users in adjacent cells use the same resources.

Step 5: The base station adapts the user's uplink according to the resource allocation result.

The step 1 is specifically: the downlink signal needs to contain the identification information of the cell or sector, for example, the downlink synchronization channel signal of the cell or sector, or the downlink pilot channel signal of the cell or sector, etc., the detected The content includes the received power value of the downlink signal and identification information of the cell or sector, and the received power value of the downlink signal is used as a measure value of the strength of the downlink signal.

The second step is specifically: comparing the downlink signal strengths of a plurality of adjacent cells or sectors with the downlink signal strengths of the own cell or sector, when the ratio of the strengths is equal to the preset threshold λ Or at a preset threshold λ, the user becomes a non-boundary user; when a value in the above intensity ratio exceeds the preset threshold λ, the user becomes a boundary user.

Described step 2 is specifically: by the user according to this cell or sector and the strength of the downlink signal of a plurality of adjacent cells or sectors, judge the information of user's geographic location in the cell or sector, and then send The judgment result is reported to the base station periodically, that is, taking time τ as the reporting period, or triggering, that is, taking the change of the geographic location information as a trigger condition.

The second step is specifically: the user reports the measurement information of the downlink signal to the base station periodically, that is, with time τ as the reporting period; or triggered, that is, with the change of the measurement information as the trigger condition, to the base station, and then by The base station makes a judgment on the geographic location information of the user in the cell or sector according to the downlink signal strengths of the cell or sector and multiple adjacent cells or sectors reported by the user.

The third step specifically includes: for a border user adjacent to one cell or sector or two cells or sectors, the number of the adjacent cell or sector needs to be reported to the base station.

The step 4 specifically includes: after the base station allocates resources to all users in the cell or sector, the cell or sector communicates and notifies the adjacent cell or sector of resource occupation by boundary users. If it is detected that the border users of this cell or sector use the same resources as the border users of adjacent cells or sectors, the SIR of the resource occupied by the border users of this cell or sector is compared with that of the adjacent cell border Compare the signal-to-interference ratio of the user. If the signal-to-interference ratio of the user at the sector border of the cell is relatively large, the right to use the resource will be reserved; if the signal-to-interference ratio of the user at the cell or sector border is small, Then give up the right to use the resource, and reallocate the resource to the non-border users of the cell or sector.

The technical scheme of the present invention is described further below:

(1) The user monitors and detects the downlink signals of the cell or sector and multiple adjacent cells or sectors

The user monitors and detects the downlink signals of multiple adjacent cells or sectors, assuming that user u is located in the cell or sector X (marked as I _X ), it monitors and detects multiple adjacent cells or sectors (set as Y, Z ,...), the downlink signal Ω needs to contain identification information I _Y , I _Z , . . . of the cell or sector. The downlink synchronization channel signal of a cell or a sector, or the downlink pilot channel signal of a cell or a sector generally contains such identification information. The content detected by the user includes the received power value of the downlink signal Ω and the identification information of the cell or sector, and the received power value of the downlink signal Ω is used as the measure value β of the strength of the downlink signal Ω.

(2) Make a judgment on the geographical location information of the user in the cell or sector

Assuming that for user u, the strength of downlink signal Ω of cell or sector X is β _X , and the strength of downlink signal Ω of multiple adjacent cells or sectors is β _Y , β _Z , ..., then, according to β _X , β _Y , β _Z , ... make a judgment on the geographic location information of the user in the cell or sector. The specific method is: compare the downlink signal strength of multiple adjacent cells or sectors The strength of the downlink signal in the area is calculated as a ratio. When there is no value in the ratio of the above strengths that exceeds the preset threshold λ, the user becomes a non-boundary user; when there is a value in the ratio of the above strengths that exceeds the preset threshold λ , the user becomes a boundary user. Write the above criterion as formula (1):

The process of judging the geographical location information of the user in the cell or sector can be realized by the user, that is, the user can use the downlink signal strength and identification information of the cell or sector and multiple neighboring cells or sectors Γ, make a judgment on the geographical location information of the user in the cell or sector, and get the judgment result Ψ, and then report Ψ periodically, that is, take time τ as the reporting period; or trigger, that is, change with Ψ Report to the base station as a trigger condition. The signaling overhead required for this report is relatively small. For example, taking a cellular system with a total of 2 ^α cell IDs as an example, each cell ID can be encoded with α bits, and only 1 bit is required for whether the user is a border user Flag bit. Therefore, the report of non-border users only needs 1 bit (1 bit is used as a flag bit whether the user is a border user), and the report of users adjacent to k cells or sectors needs 1+αk bits (1 bit is used as Whether it is a flag bit of a boundary user, αk bit is used as an identity of an adjacent cell or sector).

(3) For border users adjacent to one cell or sector or two cells or sectors, the number of the adjacent cell or sector needs to be reported to the base station. Currently, in the most commonly used 3-sector cellular system, there are special The feedback reporting method can further reduce the number of feedback bits. Feedback is divided into two parts, first feedback cell information. There are four adjacent cells to the boundary user of a single sector, which are the own cell and three adjacent cells. The two-bit codes for this cell and the three adjacent cells are 00, 01, 10, and 11 respectively. In a 3-sector cellular system, users in one sector may only be adjacent to four cells. Then, 3 sectors (identified as I ₁ , I ₂ , and I ₃ ) are respectively encoded as 01, 10, and 11 by using 2 bits for the user. The first two digits of feedback are codes of adjacent cells, the last two digits are codes of adjacent sectors, and non-border users feedback 0000. As shown in formula (2):

For example, when user u in sector 1 is a non-border user, it will feed back 0000; when user u in sector 1 is adjacent to sector 2 in cell 2, it will feed back 0110; When it is adjacent to sector 2 of cell 3, it feeds back 1010.

The process of judging the geographical position information of the user in the cell or sector can also be realized by the base station, that is, the user compares the downlink signal strength and identification information Γ of the cell or sector and multiple adjacent cells or sectors , periodically, that is, with time τ as the reporting period; or triggering, that is, with the change of measurement information as a trigger condition, report to the base station, and then the base station reports to the base station according to the current cell or sector and multiple adjacent cells or sectors The strength of the downlink signal and the identification information Γ of the area, and the user's geographic location information in the cell or sector are judged, and the geographic location judgment result Ψ is obtained. Documents organized by 3GPP: TS 25.133 V7.5.0, "Requirements for support of radio resource management (FDD) (Release7)" (equipment requirements for radio resource management under frequency division duplex conditions (version 7)), with The mechanism for the user to report measurement information to the base station is specifically: the user can report the measurement results of 32 cells or sectors to the base station periodically or triggered, and the measurement content includes the carrier-to-interference ratio (CPICH Ec/Io) of the common pilot channel, The received code word power (CPICH RSCP) of the common pilot channel, the above information can be used as the strength and identification information Γ of the downlink signal of the current cell or sector and multiple adjacent cells or sectors. In this way, the present invention does not need to send additional uplink signaling to the base station to report Γ.

(4) After the base station (located in the cell or sector X, identified as I _X ) has allocated all resources to the users in the cell or sector, communicate the resources occupied by the border user with the adjacent cells of the border user.

If the resources used by the boundary users do not conflict, the resource allocation is complete.

If the resources used by the border users conflict, interference avoidance is performed through inter-cell communication. The method for avoiding interference in inter-cell communication is described in detail below:

For a border user u of cell or sector X, assuming its adjacent cell or sector is Y, the resource occupied by the user is S(i), which can be expressed as u(X/Y, S(i)). Assume that border users of adjacent Y cells or sectors also use the same resource S(i), which can be expressed as u(Y/X, S(i)). At this time, the border users u(X/Y, S(i)) and u(Y/X, S(i)) of the adjacent cell or sector will generate interference, and the SINRs of the two are compared.

If SINR(u(X/Y, S(i))) > SINR(u(Y/X, S(i))), then users located in cell or sector X still retain use of resource S(i) Permission, the user in the cell or sector Y gives up the right to use the resource S(i), and returns the right to use the resource S(i) to the non-border user in the cell or sector Y.

If SINR(u(X/Y, S(i)))<SINR(u(Y/X, S(i))), the user located in cell or sector X gives up the right to use resource S(i) , and return the right to use the resource S(i) to non-border users of the cell or sector X. Users located in cell or sector Y retain usage rights to resource S(i).

(5) The base station adapts the user's uplink according to the resource allocation result

After the base station completes resource allocation, it adapts the user's uplink, including executing power control algorithms and adaptive modulation and coding algorithms, and generating parameters for different user uplink data, such as: used power, modulation mode, and coding rate etc., and inform the user that after receiving the above information, the user starts to send uplink data.

Some commonly used power control algorithms include maximum power allocation algorithm and target signal-to-noise ratio algorithm, see literature: 3GPP, R1-062861, "Uplink Power Control for E-UTRA", Ericsson (3GPP document, number: R1-062861, "E - Uplink Power Control in UTRA Systems", Ericsson Corporation).

The maximum power allocation algorithm is to make all users u send signals with the maximum power that users can support:

P(u)=P _max (5)

In the formula, P(u) is the uplink data power of user u, and P _max is the maximum power that the user can support.

The target signal-to-noise ratio algorithm is to first compensate the path loss of the signal sent by user u (the path loss is determined by the distance between the user and the base station, the shadow fading caused by the building conditions near the user, and the angle between the user's location and the base station antenna) , and then further increase the power of user u to achieve the target SNR, the power is upper bounded by P _max :

P(u)=min(P _max , SNR _tag P _noise /L(u)) (6)

In the formula, L(u) is the path loss of the uplink signal of user u, P _noise is the noise power, and SNR _tag is the target signal-to-noise ratio.

Partial path loss compensation algorithm is also a commonly used power control algorithm, see literature: 3GPP, R1-060401, "Interference Mitigation via Power Control and FDM ResourceAllocation and UE Alignment for E-UTRA Uplink and TP", Motorola (3GPP document, number: R1 -060401, "In the uplink of E-UTRA system, proposals for suppressing interference by power control, frequency division multiplexing resource allocation and user ordering and standardization text proposal", Motorola Corporation). The algorithm sets different transmission power values according to the path loss of different users. For the users with the worst path loss of x percent, they are allowed to send data at P _max . The function partially compensates its path loss, the power is upper bounded by _Pmax :

P(u)=P _max ×min{1, max[Pr _min , (L _x-ile /L(u)) ^α ]} (7)

In the formula, Pr _min is the ratio of the minimum power of the user to send data to the maximum power P _max , L _x-ile is the path loss at the x percentile point in the system, that is, the path loss of all users in the system is firstly increased from small to large Arranged, the path loss at x percent is L _x-ile , and α is a partial path loss compensation coefficient.

The adaptive modulation and coding algorithm refers to adaptively adjusting the modulation and coding scheme according to the user's channel conditions, resource allocation conditions, and transmission power conditions to achieve link adaptation, thereby ensuring that the packet error rate is lower than the expected value. See literature: 3GPP, R1-061525, "System Analysis for UL SIMO SC-FDMA", Qualcomm Europe (3GPP document, number: R1-061525, "Single-antenna transmission in uplink, multi-antenna reception SC-FDMA system Analysis”, Qualcomm Europe R&D Center).

The base station for suppressing co-channel interference between users involved in the present invention includes: a user geographic location acquisition unit, a user occupied resource communication unit, a resource coordination unit, and a link adaptation unit. in:

The user geographic location acquiring unit acquires the user's geographic location in a cell or sector;

The user-occupied resource communication unit notifies the base station of the adjacent cell or sector that the user at the border of the cell or sector occupies the resource;

The resource coordinating unit judges whether the border users of the neighboring cell use the same resources as the border users of the current cell according to the resources occupied by the border users of the neighboring cell. If users use the same resource, then re-allocate the resource;

The link adaptation unit adapts the user's uplink according to the resource reallocation result.

The user geographic location acquisition unit receives the downlink signal strength of the cell or sector and multiple adjacent cells or sectors reported by the user, and the identification information of the cell or sector, and analyzes the user's location in the cell or sector. Make judgments based on the geographic location information.

The user geographic location acquisition unit receives the geographic location reported by the user.

The user's geographic location acquisition unit makes a judgment on the geographic location information of the user in the cell or sector, and compares the strength of the downlink signal of the adjacent cell or sector with the strength of the downlink signal of the own cell or sector For comparison, when there is no value in the ratio of the strength of the downlink signal of the adjacent cell or sector to the strength of the downlink signal of the own cell or sector that exceeds the preset threshold value, the user becomes a non-boundary user, when When a value in the ratio exceeds a preset threshold, the user becomes a boundary user.

The resource coordinating unit reallocates the resource, and if the signal-to-interference ratio of the cell or sector boundary user on the resource is greater than that of the adjacent cell boundary user, the cell or sector boundary user reserves the resource use rights, if the signal-to-interference ratio of a cell or sector border user on the resource is smaller than that of an adjacent cell border user, the cell or sector border user will give up the resource use right, and the resource It is re-allocated to non-border users of the cell or sector.

The advantage of the present invention is that: according to the strength of the downlink signals of a plurality of adjacent cells or sectors monitored and detected by the user, the user or the base station makes a judgment on the geographical position of the user in the cell or sector, and the base station is performing resource allocation In the future, perform inter-cell communication with the adjacent cells of the border user on the resource status occupied by the border user. If the border users of the adjacent cell or sector also use the same resources, the method of inter-cell or inter-sector communication can avoid interference. generation. When realizing the goal of reducing co-channel interference among users, the present invention has the advantages of good interference suppression effect, high frequency spectrum reuse coefficient, increased output rate of border users, and the like. In comparison with the proposal of Motorola, the proposal of the present invention significantly improves the user output rate of more than 75%.

Description of drawings

Fig. 1 is a detailed flow chart of the present invention

Figure 2 is a schematic diagram of the layout and base station antenna settings of the FDD-FDMA cellular system

Figure 3 is a schematic diagram of users randomly and evenly distributed in a 7-cell cellular system

Figure 4 is a schematic diagram of interference between users in adjacent cells or sectors

Figure 5 is a schematic diagram of a method for suppressing inter-cell or inter-sector interference

Fig. 6 is a structural block diagram of the base station of the present invention

Detailed ways

The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: this embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following the described embodiment.

As shown in Figure 1, the present invention firstly monitors and detects the downlink signals of a plurality of adjacent cells or sectors, and then makes a judgment on its geographical position in the cell or sector, and periodically or It is a triggered report to the base station; or the user directly reports the measurement information of the monitored and detected downlink signal to the base station periodically or triggered, and then the base station makes a decision on the geographical location of the user in the cell or sector For judging, the base station distinguishes border users and non-border users according to different geographical locations of the users, and detects the resources allocated to the border users. If the same resource is allocated, the border user with a smaller signal-to-stem ratio will give up the right to use the resource. And reallocate the resources to non-boundary users. Thereby improving the data transmission rate of the border users of the cell or sector, while keeping the total data transmission rate of the system without obvious decline, the present invention has the advantages of high spectrum reuse coefficient and high border user efficiency when realizing the goal of reducing co-channel interference between users Advantages such as increased output rate.

A specific uplink FDD-FDMA cellular system parameter configuration is given below to illustrate the implementation steps of the present invention. It should be noted that the parameters in the following examples do not affect the generality of the present invention.

Documents organized by 3GPP: TR 25.814 V1.5.0, "Physical Layer Aspects for Evolved UTRA" (physical layer specification for evolved universal mobile communication system and land-based radio access) and R1-063013, "Approved minutes of 3GPP TSG RAN WG1# 46 in Tallinn" (the technical details adopted by the RAN WG1 group of the 3GPP international organization standard formulation working group at the 46th meeting held in Tallinn) provides a set of simulation parameter configurations for the uplink FDD-FDMA cellular system, as follows:

Parameters of uplink FDD-FDMA cellular system set up Cellular System Model and Layout Regular hexagonal honeycomb grid, the simulation uses 19 cell models, each cell has 3 sectors user distribution random uniform distribution The distance D between cell base stations 500m The attenuation function of signal power with the distance between the user and the base station L＝128.1+37.6log ₁₀ (R), the unit is dB, R is the distance between the user and the base station, the unit is Km Shadow Fading Standard Deviation 8dB Shadow Fading Correlation Distance 50m Shadow Fading Correlation Coefficient between cells 0.5 between sectors 1.0 Penetration loss 20dB Base Station Antenna Setup The angle between the inter-sector antennas is 120 degrees, and the 3dB attenuation angle of the main lobe is 70 degrees Base station antenna gain plus cable loss 14dBi

Base station noise figure 5dB thermal noise power spectral density -174dBm/Hz Minimum distance between user and base station ＞＝35m User moving speed V 3km/h The user's maximum transmit power P _max 21dBm Number of User Transmitting Antennas 1 Number of base station receiving antennas 2 Center carrier frequency 2GHz system bandwidth 5MHz Subcarrier spacing f _o 15KHz Total number of subcarriers used 300 The number of subcarriers contained in each unit resource S(i) 12 The number of units N of resources within the system bandwidth 24 (24×12=288, the remaining 300-288=12 subcarriers are used for some uplink signaling overhead, etc.) Transmission data time slot length TTI 1ms

As shown in FIG. 2, FIG. 2 is a schematic diagram of the layout of the cellular system and the antenna settings of the base station.

The simulated channel is 6-ray GSM Typical Urban Channel (6-ray TU in a typical urban area of global mobile communications, referred to as 6-ray TU), and its parameters are as follows:

Latency (us) Relative power (dB) Path 1 0 -3 Path 2 0.2 0 Path 3 0.5 -2 Path 4 1.6 -6 Path 5 2.3 -8 Path 6 5.0 -10

Other parameters in the simulation are selected as follows:

Other simulation parameters set up Number of users in each sector 10 resource scheduling method Proportional Fair Algorithm The maximum number of resource units that each user can occupy in each TTI 8 Data packet error retransmission method Append soft value merge Maximum number of retransmissions for packet errors 5 Packet Error Retransmission Delay 6 TTIs power control method Partial Path Loss Compensation Algorithm The parameter x in the partial path loss compensation algorithm 5 Parameter α in Partial Path Loss Compensation Algorithm 0.5

Parameter Pr _min in Partial Path Loss Compensation Algorithm 0.01 Scheduling frequency Executed once per TTI Scheduling delay 1 TTI User Data Queue Model Waiting to send data is infinite receiver equalizer Minimum mean square error equalizer expected packet error rate 0.1 Adaptive Modulation Coding Candidate Scheme 4 constellation point phase shift keying modulation (QPSK) Code rate = {1/3, 1/2, 2/3, 4/5} 16 constellation points quadrature amplitude modulation (16QAM) Code rate = {1/2, 2/3, 3/4, 4/5} Packet Error Rate Curves of Adaptive Modulation Coding Candidates Adopted literature: 3GPP, R1-061525, "SystemAnalysis for UL SIMO SC-FDMA", QualcommEurope (3GPP document, number: R1-061525, "Analysis of SC-FDMA systems with single-antenna transmission and multi-antenna reception in the uplink" , the curve in Qualcomm Europe R&D Center) Whether to apply the invention to a cell or a sector sector Threshold λ for distinguishing boundary users from non-boundary users 0.5 The method of reporting whether the user is a cell or sector boundary user and adjacent cells or sectors to the base station Periodic report, τ=1s

As shown in FIG. 3 , FIG. 3 is a schematic diagram of users randomly and evenly distributed in a 7-cell cellular system.

Applying the present invention to a sector, since the system is a 3-sector system, there are only 3 sector identifiers, which are I ₁ =1, I ₂ =2, and I ₃ =3.

The implementation steps of this embodiment are described as follows:

(1) The user monitors and detects the downlink signals of the cell or sector and multiple adjacent cells or sectors

This step is located in the geographic location judgment module in FIG. 1 .

FIG. 4 is a schematic diagram of interference between users in adjacent cells or sectors.

Figure 4 obtained in a certain simulation is a distribution diagram of different locations of user u located in the sector identified as #1 in cell 1 and in the sector identified as #3 in cell 4. At this time, the user monitors and detects the downlink signal Ω of the adjacent cell and the adjacent sector, and the downlink signal Ω needs to contain identification information of the cell and the sector. Let the user u identified as #1 in cell 1 detect the strength of downlink signal Ω in the sector identified as #1 in cell 1 as β ₁ , and the intensity of the strongest downlink signal Ω in the interfering sector as β ₂ . Therefore, according to β ₂ /β ₁ , a judgment can be made on the geographical location information of the user.

(2) Make a judgment on the geographical location information of the user in the cell or sector

This step is located in the geographic location judgment module in FIG. 1 .

According to formula (1), as shown in Figure 4, when the user is at position 1 in Figure 4, β ₂ /β ₁ does not exceed the preset threshold λ=0.5, so this user becomes a non-boundary user; when the user When located at position 2 in Figure 4, β ₂ /β ₁ exceeds the preset threshold λ=0.5, so the user becomes a border user and is adjacent to a sector (the sector identified as #2 in cell 2) ; When the user is at position #3 in Figure 4, β ₂ /β ₁ does not exceed the preset threshold λ=0.5, so the user becomes a non-boundary user. Similarly, when the user is located at position #4, the user is a border user and is adjacent to the sector identified as #3 in cell 4; when the user is located at position #5, the user is a border user and is identified with cell 3 The sector #2 is adjacent; when the user is located at position #6, the user is a border user and is adjacent to the sector identified as #1 in cell 1; when the user is located at position #7, the user is a non-border user; When the user is at location #8, the user is a non-boundary user. The above result is the judgment result Ψ of the geographic location.

(3) The base stations of adjacent cells or sectors notify the base stations of adjacent cells or sectors of the resources occupied by the border users of this cell or sector; users make judgments on their own geographic locations to obtain geographical location The judgment result Ψ of the position is then periodically reported to the base station, the reporting period is τ=1s, and the above list is as follows:

user location   Ψ The neighborhood to which the adjacent sector belongs   Neighboring sector identification #1

    

     #2 2 #2 #3     

    

#4 4 #3 #5 3 #2 #6 1 #1 #7     

    

#8          

(4) After the base station (located in the cell or sector X, identified as #X) has allocated all resources to users in the cell or sector, communicate the resource situation occupied by the border user with the adjacent cells of the border user.

This step is located in the resource allocation adjustment module in FIG. 1 and FIG. 5 .

In a certain implementation, if the resources used by the border users do not conflict, the resource allocation is completed.

If the resources used by the border users conflict, interference avoidance is performed through inter-cell communication.

The method for avoiding interference in inter-cell communication is described in detail below:

For a border user u of cell or sector X, assuming its adjacent cell or sector is Y, the resource occupied by the user is S(i), which can be expressed as u(X/Y, S(i)). Assume that border users of adjacent Y cells or sectors also use the same resource S(i), which can be expressed as u(Y/X, S(i)). At this time, the border users u(X/Y, S(i)) and u(Y/X, S(i)) of the adjacent cell or sector will generate interference, and the SINRs of the two are compared.

If SINR(u(X/Y, S(i))) > SINR(u(Y/X, S(i))), then users located in cell or sector X still retain use of resource S(i) Permission, the user in the cell or sector Y gives up the right to use the resource S(i), and returns the right to use the resource S(i) to the non-border user in the cell or sector Y.

If SINR(u(X/Y, S(i)))<SINR(u(Y/X, S(i))), the user located in cell or sector X gives up the right to use resource S(i) , and return the right to use the resource S(i) to non-border users of the cell or sector X. Users located in cell or sector Y retain usage rights to resource S(i).

As shown in FIG. 5, FIG. 5 is a schematic diagram of a method for suppressing inter-cell or inter-sector interference. Assuming that in a resource allocation, the resource occupation of four users in sector 1 in cell 1 is as follows: user 1 occupies resource blocks RB1 and RB2, user 2 occupies RB4 and RB5, user 3 occupies RB7 and RB8, and user 4 occupies RB3 , RB6.

For border user 4, comparing the resources occupied by it with the resources occupied by border users in its neighboring sectors, it can be found that its neighboring sector is the border user 5 of sector 3 in cell 4, and user 6 has resource usage. In conflict, user 5 is allocated resource block RB3 and user 6 is allocated resource block RB6 at the same time.

Comparing the SINR of user 4 and the SINR of user 5, it is assumed in this implementation that

For the conflicting resource RB3, SINR(4)<SINR(5), then re-allocate the conflicting resource RB3 in sector 1 of cell 1 where user 4 resides, and allocate it to the central user in sector 1 of cell 1.

For the conflicting resource RB6, SINR(4)>SINR(6), the conflicting resource RB6 of sector 1 of cell 1 where user 4 is located is reserved and allocated to user 4.

The result after resource allocation adjustment: the occupancy of resources by four users in sector 1 in cell 1 is that user 1 occupies resource blocks RB1, RB2, RB3, user 2 occupies RB4, RB5, user 3 occupies RB7, RB8, user 4 occupies RB6.

(5) The base station adapts the user's uplink according to the resource allocation result

This step is located in the uplink adaptation module in FIG. 1 .

After the base station completes resource allocation, it adapts the user's uplink, including executing power control algorithms and adaptive modulation and coding algorithms, and generating parameters for different user uplink data, such as: used power, modulation mode, and coding rate etc., and inform the user that after receiving the above information, the user starts to send uplink data.

The power control algorithm adopted in this embodiment is shown in formula (7), and its parameters are: x=5, α=0.5, Pr _min =0.01. The packet error rate curve and literature of the adaptive modulation and coding candidate scheme adopted in this embodiment: 3GPP, R1-061525, "System Analysis for UL SIMO SC-FDMA", QualcommEurope (3GPP document, number: R1-061525, ""Analysis of SC-FDMA systems with single-antenna transmission and multi-antenna reception in the uplink", the same curves in Qualcomm Europe R&D Center).

In the simulation, the performance comparison of the system adopting the method of reducing co-channel interference among users of the present invention and not using the method of the present invention is investigated. Comparing the user output rate and spectrum efficiency of Motorola and this patent solution is listed as follows:

Uplink transmission rate Motorola Solutions This patent solution 5% user output rate 153kbps 172kbps 10% user output rate 184kbps 221kbps 25% user output rate 268kbps 298kbps 50% user output rate 395kbps 398kbps 75% user output rate 527kbps 592kbps 100% user output rate 1870kbps 1223kbps average output 442kbps 460kbps

Spectral efficiency Motorola Solutions This patent solution 5% User Spectrum Efficiency 0.306 0.344 10% User Spectrum Efficiency 0.368 0.442 25% User Spectrum Efficiency 0.536 0.596 50% User Spectrum Efficiency 0.790 0.796 75% User Spectrum Efficiency 1.054 1.184 100% User Spectrum Efficiency 3.740 2.446 Average Spectral Efficiency 0.880 0.920

Therefore, the method for reducing co-channel interference between users in the uplink FDD-FDMA cellular system proposed by the present invention can use all frequency resources for border users, increases the authority of border users to use resources, and avoids their use through inter-cell communication Resource conflict, thereby improving the data transmission rate of the border users of the cell or sector, and at the same time improving the total data transmission rate of the system. It has high advantages and has high application value in the uplink FDD-FDMA cellular system.

As shown in FIG. 6, this embodiment includes: a user geographic location acquisition unit, which acquires the user’s geographic location in a cell or sector; a user occupation resource communication unit, which notifies the relevant parties of the situation that the boundary user of the cell or sector occupies resources The base station of the adjacent cell or sector; the resource coordination department, according to the resources occupied by the border users of the adjacent cell, judges whether the border users of the adjacent cell use the same resources as the border users of this cell, if the border users of the adjacent cell If the same resource as that of the user at the boundary of the cell is used, the resource is reallocated; the link adaptation unit adapts the uplink of the user according to the resource reallocation result.

Claims (9)

1. cochannel disturbs the method that suppresses between a user, it is characterized in that, comprises the steps:

Step 1: the user detects the downstream signal of this sub-district or sector and a plurality of neighbor cell or sector, obtains the intensity of described downstream signal;

Step 2: the base station obtains the information in the geographical position of user in sub-district or sector, and be specially: the user judges the geographical position of user in sub-district or sector according to the intensity of described downstream signal, reports to the base station again;

Described the geographical position of user in sub-district or sector judged, its method is: the intensity of the downstream signal of the intensity of the downstream signal of neighbor cell or sector and this sub-district or sector is made comparisons, when the ratio of the intensity of the downstream signal of the intensity of the downstream signal of neighbor cell or sector and this sub-district or sector is equal to or less than predefined threshold value, this user becomes non-boundary user, when existing numerical value to surpass predefined threshold value in the described ratio, this user becomes boundary user;

Step 3: the advisory neighbor cell of resource or the base station of sector are occupied with the boundary user of this sub-district or sector each other in the base station of neighbor cell or sector; For with a sub-district or sector or two adjacent boundary users in sub-district or sector, the number of neighbor cell or sector need be reported to the base station;

Step 4: the situation of resource is occupied in the base station according to the boundary user of neighbor cell, whether the boundary user of judging neighbor cell has used the resource identical with this cell boundary users, when the boundary user of neighbor cell has used the resource identical with this cell boundary users, then described resource is redistributed, it is bigger than the signal interference ratio of neighbor cell boundary user at the signal interference ratio of this resource promptly to work as sub-district or sector borders user, then described sub-district or sector borders user keep the rights of using to this resource, when sub-district or sector borders user littler at the signal interference ratio of this resource than the signal interference ratio of neighbor cell boundary user, then described sub-district or sector borders user abandon the rights of using of this resource, and this resource is redistributed to the non-boundary user use in this sub-district or sector;

Step 5: the base station is carried out adaptive according to described allocation result to user's up link.

2. cochannel disturbs the method that suppresses between user according to claim 1, it is characterized in that, described step 1, the content of described detection comprises the received power value of downstream signal and the identification information of sub-district or sector, with the received power value of the described downstream signal metric as the intensity of downstream signal.

3. cochannel disturbs the method that suppresses between user according to claim 2, it is characterized in that the identification information of described sub-district or sector comprises the descending synchronous signal channel signal of sub-district or sector, or the downlink pilot frequency channel signal of sub-district or sector.

4. cochannel disturbs the method that suppresses between user according to claim 1, it is characterized in that, described user is periodic report to the base station method of reporting.

5. the method that cochannel disturb to suppress between user according to claim 1 is characterized in that, described user is to the report of base station method of reporting for triggering property, changes as trigger condition with the intensity of described downstream signal.

6. cochannel disturbs the method that suppresses between user according to claim 1, it is characterized in that, the user is that the report of triggering property changes as trigger condition with the geographical position of described user in sub-district or sector to the base station method of reporting.

7. a base station is characterized in that, comprising: user geographical position acquisition unit, user occupy resource Department of Communication Force, resource coordination portion, link adaptation portion, wherein:

Described user geographical position acquisition unit is obtained the geographical position of user in sub-district or sector;

Described user geographical position acquisition unit, information to the geographical position of described user in sub-district or sector judges: the intensity of the downstream signal of the intensity of the downstream signal of neighbor cell or sector and this sub-district or sector is made comparisons, when not existing numerical value to surpass predefined threshold value in the ratio of the intensity of the downstream signal of the intensity of the downstream signal of neighbor cell or sector and this sub-district or sector, this user becomes non-boundary user, when existing numerical value to surpass predefined threshold value in the described ratio, this user becomes boundary user;

Described user occupies the resource Department of Communication Force, and the boundary user of this sub-district or sector is occupied the advisory neighbor cell of resource or the base station of sector;

Described resource coordination portion, the situation of occupying resource according to the boundary user of neighbor cell, whether the boundary user of judging neighbor cell has used the resource identical with this cell boundary users, when the boundary user of neighbor cell has used the resource identical with this cell boundary users, then described resource is redistributed, it is big at the signal interference ratio of the signal interference ratio neighbor cell boundary user of this resource promptly to work as sub-district or sector borders user, then described sub-district or sector borders user keep the rights of using to this resource, when sub-district or sector borders user little at the signal interference ratio of the signal interference ratio neighbor cell boundary user of this resource, then described sub-district or sector borders user abandon the rights of using of this resource, and this resource is redistributed to the non-boundary user use in this sub-district or sector;

Described link adaptation portion redistributes the result according to resource, carries out adaptive to user's up link.

8. base station according to claim 7, it is characterized in that, described user geographical position acquisition unit, receive the intensity of downstream signal of this sub-district of user report or sector and a plurality of neighbor cell or sector and the identification information of sub-district or sector, the information in the geographical position of described user in sub-district or sector is judged.

9. according to claim 7 or 8 described base stations, it is characterized in that described user geographical position acquisition unit, the geographical position of reception user report.

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