CN100553357C - Method for reducing co-channel interference between users in uplink FDMA cellular system - Google Patents

Abstract

The present invention relates to a method for reducing co-channel interference between users in an uplink FDMA cellular system in the field of communication technology. A base station divides boundary user dedicated resources for boundary users therein, and guarantees boundary user dedicated resources between adjacent cells or sectors There is no overlap, the user listens to and detects the downlink signal containing identification information of the local cell or sector and the adjacent cell or sector, obtains the detection information of the downlink signal, and then judges the user's anti-interference and interference with users in the adjacent cell or sector Then, according to the result, the base station allocates resource usage rights, performs resource scheduling, allocates resources, and finally adapts the user's uplink. When realizing the goal of reducing co-channel interference between users, the present invention has the advantages of high frequency spectrum reuse coefficient, high overall data transmission rate of the system, simple implementation, less signaling interaction between users and base stations, and the like.

Description

Method for reducing co-channel interference between users in uplink FDMA cellular system

technical field

The invention relates to a method for reducing co-channel interference in the field of communication technology, in particular to a method for reducing co-channel interference between users applied to an uplink FDMA cellular system.

Background technique

FDMA (Frequency Division Multiple Access) is the main multiple access method adopted by the cellular system, and its characteristic is that different users use different frequency spectrum resources when accessing the system. Currently, OFDM (Orthogonal Frequency Division Multiplexing) technology and SC-OFDM (Single-Carrier Orthogonal Frequency Division Multiplexing) technology are the main technologies for realizing the FDMA mode. 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 FDMA cellular system.

Generally, the cellular system divides the service coverage area into several regular hexagonal cells. At present, each cell is generally divided into 3 sectors or 6 sectors equally. In an uplink FDMA cellular system, a cell or sector base station allocates uplink resources (hereinafter referred to as resources) and uplink power to users. Resources generally 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 some technical documents, for the uplink FDMA cellular system required by EUTRA, there are four methods that can be used to reduce co-channel interference between users:

(1) Simple inter-cell or sector interference coordination/avoidance method: each cell or sector uses only a part of resources, called "cell or sector-specific resources", and ensures that the dedicated resources of adjacent cells or sectors are not overlap, so as to avoid severe co-channel interference between users at the cell or sector boundary. Since the dedicated resources of each cell or sector cannot be reused by adjacent cells or sectors, its spectrum reuse coefficient is greatly reduced, resulting in a significant decrease in the overall data transmission rate of the system. See patent: "Subcarrier Allocation Method for Reducing Inter-cell Interference in Orthogonal Frequency Division Multiplexing Cellular Environment", application (patent) number: 200480006260.4, publication (announcement) number: CN1759582, applicant (patent) person: LG Electronics Co., Ltd. )

(2) Inter-cell interference coordination/avoidance method with high spectrum reuse coefficient: each cell or sector allocates specific resources for its boundary users, called "boundary user-dedicated resources", and guarantees that There is no overlapping of border user-specific resources between adjacent cells or sectors, thereby avoiding serious co-channel interference among users at cell or sector borders. The border user dedicated resource can be reused by non-border users in adjacent cells, so its frequency spectrum reuse coefficient is relatively high. See literature: 3GPP, R1-050629, "Inter-cell interference mitigation", Huawei. (3GPP document, number: R1-050629, "Inter-cell interference suppression method", Huawei company)

(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. See literature: 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) The method of combining inter-cell interference coordination/avoidance with interference cancellation: the entire resource is divided into resources applicable to interference coordination/avoidance and resources applicable to interference cancellation without intersection, and for resources applicable to interference coordination/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. See literature: 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 advantages of simple implementation and no need for coordinated communication between cells or sectors, but has the disadvantage of low spectrum reuse coefficient; method (2) maintains the advantages of method (1) and has a higher frequency spectrum reuse However, when allocating resources for border users, due to the limited available resources, the efficiency of resource scheduling will be greatly reduced, so that the total data transmission rate of the system will be greatly reduced; method (3) overcomes method The disadvantage of (2) also has a high spectrum reuse factor, but it requires a large computational overhead to reconstruct and eliminate interference signals, or needs to introduce certain inter-cell coordination to establish interference user pairs/groups to simplify Calculation; method (4) combines method (2) and method (3), but it is necessary to divide the resources applicable to interference coordination/avoidance and the resources applicable to interference cancellation, and use different methods for reducing co-channel interference between users, This increases the implementation complexity of the whole solution. In addition, in order to ensure the adaptability of the method, it is also necessary 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 solve the problems in the prior art that the spectrum reuse coefficient is low, or the total data transmission rate of the system is low, or the implementation complexity is high, or there are many signaling interactions between the user and the base station, A method for reducing co-channel interference between users in an uplink FDMA cellular system is provided. The present invention is a method for coordinating/avoiding interference between cells or sectors. Each cell or sector allocates border user-specific resources for border users therein, and ensures that the border user-dedicated resources between adjacent cells or sectors do not overlap. The border user dedicated resources can be reused by non-border users in adjacent cells or sectors, so as to ensure a high frequency spectrum reuse factor in the present invention.

In the implementation process of the present invention, firstly, the user monitors and detects the downlink signals of a plurality of adjacent cells or sectors, and then makes a judgment on its own anti-interference and interference with users in adjacent cells or sectors, and uses the anti-interference Interference and interference The situation of users in adjacent cells or sectors is periodically or triggered to report to the base station; or the user directly monitors and detects the measurement information of the downlink signal to the base station periodically or triggered Report, and then the base station makes a judgment on the user's anti-interference and interference with users in adjacent cells or sectors. In this process, there is less signaling interaction between the user and the base station. Finally, the base station allocates different resource usage rights according to the user's different anti-interference and interference with users in adjacent cells or sectors. Resources, and may reduce its transmit power to reduce its co-channel interference to border users of adjacent cells or sectors, thereby increasing the data transmission rate of border users of cells or sectors; for those that are not easy to interfere with adjacent cells For the users in the sector or users in the sector, the base station makes it possible to use the resources dedicated to the border users of the cell or sector as a backup, or may increase its transmission power to keep the total data transmission rate of the system high. The distribution process is relatively simple. Therefore, when the present invention achieves the goal of reducing co-channel interference between users, it has the advantages of high spectrum reuse coefficient, high overall data transmission rate of the system, simple implementation, and less signaling interaction between users and base stations.

The present invention is realized through the following technical solutions, specifically comprising the following steps:

Step 1: Each cell or sector allocates border user-specific resources for its border users, and ensures that border user-dedicated resources between adjacent cells or sectors do not overlap. The border user-dedicated resources can be used by adjacent cells or sectors Multiplexing of non-border users in the area;

Step 2: The user monitors and detects the downlink signals containing identification information of the own cell or sector and adjacent cells or sectors, and obtains the detection information of the downlink signals;

Step 3: According to the detection information of the downlink signal, judge the anti-interference of the user and the situation of the user in the adjacent cell or sector;

Step 4: The base station allocates resource usage rights according to the user's anti-interference and interference with users in adjacent cells or sectors;

Step 5: The base station executes resource scheduling and allocates resources according to the user's authority to use resources;

Step 6: The base station adapts the user's uplink according to the resource allocation result.

In the second step, the detection information includes: identification information of a cell or sector and a path loss value from the user to the cell or sector.

In the third step, the user judges the user's anti-interference and interference with the user in the adjacent cell or sector according to the detection information, and then reports the judgment result to the base station; or the user reports the detection information to the base station, Based on the detection information, the base station judges the user's anti-interference and interference with users in adjacent cells or sectors.

In said step 3, judging the user's anti-interference and interference with the user in the adjacent cell or sector refers to: comparing the path loss value from the user to the cell or sector with the anti-interference path loss threshold value , if it exceeds the threshold value, the user is a user with strong anti-interference ability, otherwise, the user is a user with weak anti-interference ability; or the path loss threshold value of the user in the sector, if it exceeds the threshold value, the user is likely to interfere with the user in the adjacent cell or the sector; otherwise, the user is not likely to interfere with the user in the adjacent cell or the sector. Therefore, all users are divided into four categories: strong anti-interference ability and easy to interfere with users in adjacent cells or sectors, strong anti-interference ability and not easy to interfere with users in adjacent cells or sectors, weak anti-interference ability and easy Interfering with users in adjacent cells or sectors, weak anti-interference ability and not easy to interfere with users in adjacent cells or sectors.

In the third step, the user reports to the base station periodically; or the user reports to the base station with his own anti-interference and interference with users in adjacent cells or sectors as trigger conditions.

In the step 4, the allocation of resource use rights refers to: for users with strong anti-interference ability and easy to interfere with users in adjacent cells or sectors, if the border user-dedicated resources of the cell or sector that may be interfered and the remaining resources other than the border user-dedicated resources of the cell or sector are not empty sets, the base station makes it not authorized to use the border user-dedicated resources of the cell or sector that may be interfered and the border user-dedicated resources of the cell or sector resources, but has the right to use the remaining resources, if the remaining resources are an empty set, the base station gives it the right to use the resources dedicated to the border users of the cell or sector, and has no right to use the border users other than the cell or sector Resources other than dedicated resources; for users who have strong anti-interference ability and are not easy to interfere with users in adjacent cells or sectors, the base station gives them the right to use resources other than the dedicated resources of border users in this cell or sector, and or the sector's border user-dedicated resources have alternate use rights; for users with weak anti-interference ability and easy to interfere with users in adjacent cells or sectors, and users with weak anti-interference ability and not easy to interfere with users in adjacent cells or sectors , the base station grants it the right to use the border user-dedicated resources of its own cell or sector, and has no right to use resources other than the border user-dedicated resources of its own cell or sector.

In the fourth step, for users with weak anti-interference ability and not easy to interfere with users in adjacent cells or sectors, the base station increases the transmission power to obtain a higher data transmission rate; for users with strong anti-interference ability and easy interference For users in adjacent cells or sectors, the base station reduces the transmit power to reduce interference to users in adjacent cells or sectors.

In the step 5, the resource scheduling refers to: firstly, the base station allocates resources other than the resources dedicated to border users in the cell to users who have permission to use the resources, and then the base station allocates resources dedicated to border users to the users The user who has the right to use the resource, and finally, the base station will allocate the unused border user-specific resource to the user who has the resource demand and has the alternate use right to the resource.

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

(1) Each cell or sector allocates resources dedicated to border users for border users in it

First, the resources in the uplink FDMA cellular system are sequentially numbered 1, 2, ..., N according to the smallest unit, so all resources can be expressed as a set S, containing (C(S)=N) elements:

S＝{S(i)1≤i≤C(S), S(i)＜S(i+1), 1≤S(i)≤N}    (1)

Then, divide S into B disjoint sets as border user-specific resources S(j) (j is the index number of border user-specific resources, 1≤j≤B), where B is a system design parameter, for example, for For a 3-sector system, B=3 can be set. S(j) contains C(S(j)) elements respectively:

S(j)＝{S _j (i)|1≤i≤C(S(j)), S _j (i)＜S _j (i+1), S _j (i)∈S}(1≤j ≤B) (2)

Moreover, S(j) satisfies:

Finally, each cell or sector selects one S(j) as its border user-dedicated resource, and ensures that adjacent cells or sectors select different S(j), so that the border user-dedicated resources of adjacent cells or sectors do not overlap each other, that is, let the sequential label of the cell or sector be X (X=1, 2, ...), and its identification be I _X (I _X ∈ I, I is the identification of the cell or sector in the cellular system set), the mapping function from the cell or sector identifier I _X to the border user-specific resource index number j is J(I _X ), so the corresponding border user-specific resource is S(J(I _X )), then,

J(I _Y )≠J(I _Z ) (when sectors/cells Y and Z are adjacent)

(4)

Right now,

In addition, the resources dedicated to border users of a cell or sector can be reused by non-border users in adjacent cells or sectors to obtain a higher spectrum utilization factor, that is, when cells or sectors Y and Z are adjacent, S (J(I _Y )) can be used by non-border users in cell or sector Z, and S(J(I _Z )) can be used by non-border users in cell or sector Y.

(2) The user monitors and detects downlink signals containing identification information of the cell or sector and adjacent cells or sectors

The user listens to and detects the downlink signals of the cell or sector and the adjacent cell or sector, assuming that user u is located in the cell or sector X (identified as I _X ), and its adjacent cells or sectors are Y, Z, .. .(identified as I _Y , I _Z , . . . ). User u listens to and _detects downlink signals Ω from _X , Y, _Z , . 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 of user detection includes the average received power value β _X , β _Y , β _Z , ... of the downlink signal Ω and the identification information of the cell or sector, and divide β _X , β _Y , β _Z , ... by the downlink signal Ω The transmit power value is used to obtain the path loss values PL _X , PL Y , PL Z , . . . from the user to the cell or sector X, _Y , _Z , . . . The path loss value generally includes the distance loss from the user to the cell or sector (the radio wave propagates in space, and its wave intensity decreases with the increase of the propagation distance, resulting in distance loss), shadow fading (due to the possible existence of building blocks Propagation of radio waves, causing shadow fading) and antenna direction angle receiving gain (because radio waves shoot at different angles to the antenna, the gain is different, therefore, the direction angle of the user's signal to the receiving antenna of the cell or sector determines the size of its gain).

(3) Judging the user's anti-interference and interference with users in adjacent cells or sectors

Assuming that the path loss value of user u to this cell or sector X is PL _X , and the path loss value of user u to multiple adjacent cells or sectors Y, Z, ... is PL _Y , PL _Z , ..., then, it can be According to PL _X , PL _Y , PL _Z , ... judge the user's anti-interference and interference with the user in the adjacent cell or sector, the specific method is: the path loss value PL _X from the user to the cell or sector X Compared with the path loss threshold Λ of anti-interference, if PL _X is greater than Λ, the user is a user with strong anti-interference ability, otherwise, the user is a user with weak anti-interference ability; Or the path loss value PL _Y , PL _Z , ... of _the sector is _compared with the path loss threshold value Θ of the user in the interfering adjacent cell or sector, if there is a certain value or some If a value is greater than Θ, the user is likely to interfere with users in adjacent cells or sectors; otherwise, the user is not likely to interfere with users in adjacent cells or sectors. Therefore, all users are divided into four categories: strong anti-interference ability and easy to interfere with users in adjacent cells or sectors, strong anti-interference ability and not easy to interfere with users in adjacent cells or sectors, weak anti-interference ability and easy Interfering with users in adjacent cells or sectors, weak anti-interference ability and not easy to interfere with users in adjacent cells or sectors. Write the above criterion as formula (5):

The process of judging the user's anti-interference and interference with users in adjacent cells or sectors can be realized by the user, that is, the user can make a judgment based on the path loss of the user to the cell or sector and multiple adjacent cells or sectors Values PL _X , PL _Y , PL _Z , ... and the identification information Γ, make a judgment on the user's anti-interference and interference with the user in the adjacent cell or sector, and obtain the judgment result Ψ, and then calculate Ψ periodically, that is, by The time τ is the reporting period; or it is triggered, that is, the change of Ψ is used as the trigger condition, and the report is reported to the base station. 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 coded with α bits, and the strength and weakness of the user's anti-interference ability only depends on 1-bit flag is required; users are not easy to interfere with users in adjacent cells or sectors and only 1-bit flag is needed, and reports that users are likely to cause interference to users in k cells or sectors require 1+αk bits (1 bit as Whether the user is likely to interfere with the user in the adjacent cell or sector is a flag bit, and the αk bit is used as the identity of the interfered cell or sector).

In particular, in the currently most commonly used 3-sector cellular system, there is a special feedback reporting manner, which can further reduce the number of feedback bits. The 3 sectors (identified as I ₁ , I ₂ , and I ₃ ) are coded as 01, 10, and 11 respectively by using 2 bits. Since in a 3-sector cellular system, it is impossible for a sector identified as _IX to be adjacent to another sector identified as _IX and cause interference, so whether users in sector X are likely to interfere with adjacent cells or There are only 4 types of users in the sector, and only 2 bits are needed for feedback, as shown in formula (6):

For example, when user u in sector 1 is not likely to interfere with adjacent cells or users in the sector, it will feed back 00; when user u in sector 1 is likely to interfere with users in sector 2, it will feed back 10; when When user u in sector 1 tends to interfere with users in sector 3, it feeds back 11; when user u in sector 1 tends to interfere with users in sectors 2 and 3, it feeds back 10. When the above feedback method is not used, when user u in sector 1 tends to interfere with users in sectors 2 and 3, 1+4=5 bits need to be fed back, and the feedback signal load will increase by 150% in net.

In the above manner, the total number of feedback bits for the user is 3 bits (1 bit indicates the strength or weakness of the user's anti-interference ability; 2 bits indicate whether the user is likely to interfere with adjacent cells or users in the sector).

The process of judging the user's anti-interference and interference with users in adjacent cells or sectors can also be implemented by the base station, that is, the path loss of the user to the cell or sector and multiple adjacent cells or sectors The values PL _X , PL _Y , PL _Z , ... and the identification information Γ are reported to the base station periodically, that is, taking time τ as the reporting period; or triggering, that is, taking the change of the measurement information as the trigger condition, and then by Based on the path loss values PL _X , PL _Y , PL _Z , ... and the identification information Γ from the user to the cell or sector and multiple adjacent cells or sectors, the base station can provide anti-interference to the user and adjacent cells or sectors Make a judgment on the situation of users in the area, and get the judgment result Ψ. Documents organized by 3GPP: TS 25.133V7.5.0, "Requirements for support of radio resource management (FDD) (Release 7)" (equipment requirements for radio resource management under frequency division duplex conditions (Release 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 received code word power of the common pilot channel (CPICH RSCP), etc. The above information can be used as the average received power values β _X , β _Y , β _Z , . In this way, during the implementation of the present invention, the user does not need to send additional uplink signaling to the base station.

(4) Access to resources allocated by the base station

The base station allocates resource usage rights according to the judgment information Ψ of the user's anti-interference and interference with users in adjacent cells or sectors. Specifically:

则基站使其有权限使用本小区或扇区的边界用户专用资源S(J(I_X))，无权限使用除本小区或扇区的边界用户专用资源以外的资源S\(S(J(I_X)))；对于抗干扰能力强且不易于干扰相邻小区或扇区内用户的用户u，基站使其有权限使用除本小区或扇区的边界用户专用资源以外的资源R(u)＝S\(S(J(I_X)))，并对本小区或扇区的边界用户专用资源S(J(I_X))有候补使用权限；对于抗干扰能力弱且易于干扰相邻小区或扇区内用户的用户和抗干扰能力弱且不易于干扰相邻小区或扇区内用户的用户，基站使其有权限使用本小区或扇区的边界用户专用资源R(u)＝S(J(I_X))，无权限使用除本小区或扇区的边界用户专用资源以外的资源S\(S(J(I_X)))。In a cell or sector X (identified as I _X ), for a user u who has strong anti-interference ability and is easy to interfere with users in the cell or sector Y, Z, ..., if the boundary of the cell or sector that may be interfered User-dedicated resource S(J(O _Y ))∪S(J(I _Z ))∪...and the remaining resource R(u) other than the border user-dedicated resource S(J(I _X )) of the cell or sector = S\(S(J(I _X ))∪S(J(I _Y ))∪S(J(I _Z ))∪…) is not an empty set, then the base station gives it the right to use the remaining resource R( u), if

Then the base station makes it authorized to use the border user dedicated resources S(J(I _X )) of the cell or sector, and has no right to use resources S\(S(J(J(J( I _X ))); For a user u who has strong anti-interference ability and is not easy to interfere with users in adjacent cells or sectors, the base station makes it authorized to use resources R(u )=S\(S(J(I _X ))), and have alternate use rights for the border user dedicated resource S(J(I _X )) of this cell or sector; for weak anti-interference ability and easy to interfere with adjacent cells Or users in the sector and users with weak anti-interference ability and not easy to interfere with adjacent cells or users in the sector, the base station gives them the right to use the border user-dedicated resources of this cell or sector R(u)=S( J(I _X )), no right to use resources S\(S(J(I _X ))) other than the border user-specific resources of the cell or sector.

In addition, in order to further increase the data transmission rate of border users, for users with weak anti-interference ability and not easy to interfere with users in adjacent cells or sectors, the base station can increase the transmission power to obtain a higher data transmission rate; in order to further To reduce co-channel interference in the system, for users with strong anti-interference ability and easy to interfere with users in adjacent cells or sectors, the base station can reduce the transmission power to reduce interference to users in adjacent cells or sectors.

Write the above criterion as formula (7):

The result of the user's permission to use resources obtained from formula (7) is Φ.

(5) The base station allocates resources according to the user's authority to use resources

The base station executes a resource scheduling algorithm and allocates resources according to the result Φ of the user's permission to use resources. Commonly used resource scheduling algorithms include maximum load-to-interference ratio algorithm, proportional fairness algorithm, and so on. See literature: Ofuji, Y.Morimoto, A.Abeta, S.Sawahashi, M. "Comparison of packets scheduling algorithms focusing on user throughput in high speed downlink packet access", The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio. Communications, VOL 3. Sept.2002page(s): 1462-1466 ("Comparison of Scheduling Algorithms for Improving User Data Transmission Rate in High-Speed Downlink Packet Data Transmission", The 13th IEEE International Discussion on Personal Communication, Indoor Communication and Mobile Wireless Communication meeting).

The maximum carrier-to-interference ratio algorithm is to allocate resource S(i) to user u with the best channel condition on S(i):

$\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Interf</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; noise</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span>$

$<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

In the formula, A(S(i)) represents the allocation function for allocating resources S(i) to users, H(u, S(i)) represents the channel power gain of user u on S(i), Interf(S (i)) represents the power of interference on S(i), and Noise(S(i)) represents the power of noise on S(i).

The proportional fairness algorithm is to allocate resources to user u, so that the ratio of the new transmission data amount that S(i) will bring to user u to user u's obtained transmission data rate is the largest:

$\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; max</span>}}<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In the formula, d(u, S(i)) represents the amount of newly transmitted data that S(i) will bring to user u, and r(u) represents the obtained transmission data rate of user u.

When the base station (located in cell or sector X, identified as I _X ) allocates resources, it first allocates resources S\S(J(I _X )) other than border user-specific resources to users who have permission to use the resources, Next, the base station allocates the border user-specific resource S(J(I _X )) to the user who has the right to use the resource. However, when there is no user authorized to use S(J(I _X )) in the cell or sector, or S(J(I _X )) has not been used up, or because the user authorized to use S(J(I X ) I _X )) user’s channel condition on S(J(I _X )) is too bad, and when the resource is given up, the base station will use the unused boundary user dedicated resource S(J(I _X )) _unused Allocate to users who have resource requirements and have alternate use rights for the resources, so as to improve the spectrum reuse factor of the cellular system.

(6) 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 (10)

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)) (11)

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 ]} (12)

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 advantage of the present invention is that: the base station allocates different resource usage rights according to user anti-interference and interference with users in adjacent cells or sectors. resources used, and may reduce its transmit power to reduce its co-channel interference to border users of adjacent cells or sectors, thereby increasing the data transmission rate of border users of cells or sectors; for those that are not prone to interference For users in adjacent cells or sectors, the base station makes it possible for the base station to have alternate use rights for the border user-specific resources of this cell or sector, or may increase its transmission power to keep the total data transmission rate of the system from dropping significantly. Therefore, When realizing the goal of reducing co-channel interference between users, the present invention has the advantages of high frequency spectrum reuse coefficient, high overall data transmission rate of the system, simple implementation, less signaling interaction between users and base stations, and the like. It has high application value in uplink FDMA cellular system.

Description of drawings

Figure 1 is a schematic diagram of the layout of the cellular system, base station antenna settings and user distribution

The module schematic diagram of Fig. 2 the present invention

Fig. 3 is a flow chart of the present invention

Figure 4 is a schematic diagram of constructing S(j) by continuously selecting resource units

Figure 5 is a schematic diagram of constructing S(j) by selecting resource units at equal intervals

Figure 6 is a schematic diagram of constructing S(J(I _X )) by continuously selecting resource units

Figure 7 is a schematic diagram of constructing S(J(I _X )) by selecting resource units at equal intervals

Figure 8 is a schematic diagram of sector identification planning for a 6-sector system

Figure 9 is a schematic diagram of constructing S(j) by continuously selecting resource units in a 6-sector system

Figure 10 is a schematic diagram of constructing S(j) by selecting resource units at equal intervals in a 6-sector system

Figure 11 is a schematic diagram of constructing S(J(I _X )) by continuously selecting resource units in a 6-sector system

Figure 12 is a schematic diagram of constructing S(J(I _X )) by selecting resource units at equal intervals in a 6-sector system

FIG. 13 is a distribution diagram of different locations of users located in the sector marked as _I1 in cell ①.

Detailed ways

A specific uplink 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 FDMA cellular system, as follows:

Fig. 1 is a schematic diagram of the layout of the cellular system and the base station antenna settings and user distribution.

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:

Delay (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 of the present invention are selected as follows:

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.

2 is a schematic diagram of modules of the present invention, wherein, U: user; B: base station; S-B: serving base station; C: service range of serving base station; Ω: downlink signal; Γ: The result of the user detecting the downlink signal (Ω); G: The unit for judging the user's anti-interference and interference with users in adjacent cells or sectors; Ψ: The user's anti-interference and interference with users in adjacent cells or sectors The result of the situation; RC: Resource Rights Allocation Unit; RA: Resource Allocation Unit; LA: Link Adaptation Unit

The user U includes a monitoring unit M that monitors the downlink signal Ω of the base station B, and optionally includes a unit G that judges user U's anti-interference and interference with users in adjacent cells or sectors; the base station B includes a resource authority allocation unit RC, resource The allocation unit RA, the link adaptation unit LA, optionally include a unit G for judging user U's anti-interference and interference with users in adjacent cells or sectors. After user U monitors and detects the downlink signal Ω of base station B, it reports the detection result Γ, or the result Ψ of user U's anti-interference and interference with users in adjacent cells or sectors, to the serving base station S-B, and the serving base station S-B according to The monitoring result Γ, or directly according to the user U's report, obtains the user U's anti-interference and interference results Ψ of users in adjacent cells or sectors, and then uses the resource authority allocation unit RC to determine the user U's authority to use resources. Allocation, obtain the allocation result Φ, then allocate resources to the user U through the resource allocation unit RA, and finally adapt the uplink of the user U through the link adaptation unit LA.

Fig. 3 is a flowchart of the present invention, and in conjunction with Fig. 3 the implementation steps of the present invention are set forth as follows:

(1) Each cell or sector allocates resources dedicated to border users for border users in it

This step is located in the coordination module of multi-cell or sector border user-dedicated resources in FIG. 3 .

Since N=48, so S={S(i)|1≤i≤C(S), S(i)<S(i+1), 1≤S(i)≤48}, C(S)= 48. Then, divide S into disjoint B=3 sets as sector boundary user-specific resources S(j) (1≤j≤3). The general division method is to construct S(j) by continuously selecting resource units, and make the number of elements in S(j) equal:

S(1)={1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}C(S(1))=16 (13)

S(2)={17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}C(S(2))=16 (14)

S(3)={33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48}C(S(3))=16(15) S(j) constructed according to formula (13), formula (14) and formula (15) meets the requirements of formula (3). A schematic diagram of the above-mentioned configuration of S(j) is shown in FIG. 4 .

In order to improve the frequency diversity effect, S(j) is constructed by selecting resource units at equal intervals, and the number of elements in S(j) is equal. See literature: 3GPP, R1-050629, "Inter-cell interference mitigation", Huawei. (3GPP document, number: R1-050629, "Inter-cell interference suppression method", Huawei company)

S(1)={1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46}C(S(1))=16 (16)

S(2)＝{2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47}C(S(2))＝16 (17)

S(3)＝{3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48}C(S(3))＝16 (18)

S(j) constructed according to formula (16), formula (17) and formula (18) meets the requirements of formula (3). A schematic diagram of the above-mentioned configuration of S(j) is shown in FIG. 5 .

In order to improve the effect of time diversity, each sector selects the boundary user dedicated resource S(j) in rotation with time, namely:

J(I _X ) = mod((I _X + TTI_dx), 3) + 1 I _X ∈ {1, 2, 3} (19)

In the formula, TTI_idx is the index number of TTI, representing the time variable. Obviously, J(I _X ) and S(J(I _X )) constructed according to formula (19) meet the requirements of formula (4). The realization of formula (19) is shown in the following table:

TTI_idx J(I₁)＝J(1) J(I₂)＝J(2) J(I₃)＝J(3) 1 3 1 2 2 1 2 3 3 2 3 1 4 3 1 2 ... ... ... ...

Fig. 6 is a schematic diagram of constructing S(J(I _X )) according to formula (19) in constructing S(j) by continuously selecting resource units, and Fig. 7 is constructing S(j by selecting resource units at equal intervals ) according to formula (19) to construct the schematic diagram of S(J(I _X )).

If a 6-sector system is adopted, S can be divided into disjoint B=4 sets as sector boundary user-specific resources S(j) (1≤j≤4). The sector identification planning is shown in Figure 8, and the planning scheme in Figure 8 can ensure that adjacent sectors use different sector identifications. Similarly, in a 6-sector system, the schematic diagram of constructing S(j) by continuously selecting resource units is shown in Figure 9, and the schematic diagram of constructing S(j) by selecting resource units at equal intervals is shown in Figure 10 Show. The schematic diagram of constructing S(J(I _X )) in S(j) according to formula (19) by continuously selecting resource units is shown in Figure 11, and selecting resource units at equal intervals to construct S(j) according to The schematic diagram of the structure S(J(I _X )) in formula (19) is shown in Fig. 12 .

(2) The user monitors and detects downlink signals containing identification information of the cell or sector and adjacent cells or sectors

This step is located in the module where the user monitors and detects downlink signals in FIG. 3 .

Figure 13 obtained in a certain simulation is a distribution map of different locations of user u located in the sector identified as I ₁ in cell ①. At this time, the user monitors and detects the downlink signal Ω of two adjacent sectors (the sector marked as _I2 and the sector marked as _I3 ), and the downlink signal Ω needs to contain the sector identification information _I2 and I ₃ . Assuming that the user u detects the average received power value of the downlink signal Ω of the sector marked I ₁ as β ₁ , the average received power values of the downlink signal Ω of the sector marked I ₂ and the sector marked I ₃ are respectively is β ₂ , β ₃ . Therefore, divide β ₁ , β ₂ , and β ₃ by the transmit power value of the downlink signal Ω to obtain the path loss values PL ₁ , PL ₂ , and PL ₃ from the user to sectors I ₁ , I _{2 ,} and I ₃ , and then to the user Judgment on the anti-interference and interference of users in adjacent cells or sectors.

(3) Judging the user's anti-interference and interference with users in adjacent cells or sectors

This step is located in FIG. 3 , which is a module for judging user anti-interference and interference with users in adjacent cells or sectors.

According to formula (5), when the user is at position #1 in Figure 13, PL ₁ > Λ, PL ₂ > Θ, PL ₃ > Θ, the user has strong anti-interference ability and is easy to interfere with sector 2 and sector 3 users in sector 2; when the user is at position #2 in Figure 13, PL ₁ > Λ, PL ₂ > Θ, PL ₃ < Θ, the user has strong anti-interference ability and is easy to interfere with users in sector 2; when the user When located at position #3 in Figure 13, PL ₁ <Λ, PL ₂ <Θ, PL ₃ >Θ, the user has weak anti-interference ability and is easy to interfere with users in sector 3; when the user is located at the position in Figure 13 At #4, PL ₁ >Λ, PL ₂ <Θ, PL ₃ <Θ, the user has strong anti-interference ability and is not easy to interfere with users in adjacent cells or sectors; when the user is at position #5 in Figure 13 , PL ₁ <Λ, PL ₂ <Θ, PL ₃ <Θ, the user has weak anti-interference ability and is not easy to interfere with users in adjacent cells or sectors; when the user is at position #6 in Figure 13, PL ₁ >Λ, PL ₂ <Θ, PL ₃ <Θ, the user has strong anti-interference ability and is not easy to interfere with users in adjacent cells or sectors. The above result is the judgment result Ψ of the user's anti-interference and interference with the user in the adjacent cell or sector.

In this embodiment, the user makes a judgment on his own anti-interference and interference with users in adjacent cells or sectors, obtains the judgment result Ψ, and then periodically reports to the base station, the reporting period is τ=1s, the above The process is the left branch in the judging module of the user's anti-interference and interference with users in adjacent cells or sectors in FIG. 3 . In the 3-sector cellular system of this embodiment, a 3-bit feedback reporting method is adopted. Set the flag bit with strong anti-interference ability to 1, and the flag bit with weak anti-interference ability to be 0. When identifying whether a user is likely to interfere with a user in an adjacent cell or a sector, the identities I ₁ , I ₂ , and I ₃ of the three sectors are encoded as 01, 10, and 11 respectively with 2 bits.

According to formula (6), when the user is at position #1 in Figure 13, the user has strong anti-interference ability and is easy to interfere with users in sector 2 and sector 3, and its feedback is 101; when the user is at position #1 in Figure 13 At position #2, the user has strong anti-interference ability and is easy to interfere with users in sector 2, and its feedback is 110; when the user is at position #3 in Figure 13, the user has weak anti-interference ability and is easy to interfere with sector For users within 3, the feedback is 011; when the user is at position #4 in Figure 13, the user has strong anti-interference ability and is not easy to interfere with users in adjacent cells or sectors, and the feedback is 100; when the user is at position #4 in Figure 13 When the user is at position #5 in Figure 13, the user has weak anti-interference ability and is not easy to interfere with users in adjacent cells or sectors, and it feedbacks 000; when the user is at position #6 in Figure 13, the user has strong anti-interference ability, And it is not easy to interfere with users in adjacent cells or sectors, and its feedback is 100.

List the above feedback as follows:

(4) Access to resources allocated by the base station

This step is located in the resource authority allocation module in FIG. 3 .

The base station allocates resource usage rights according to the judgment information Ψ of the user's anti-interference and interference with users in adjacent cells or sectors. In the sector marked as I ₁ in the cell ①, the base station restricts the resources that the base station is authorized to use for users who are likely to interfere with users in adjacent cells or sectors, and may reduce their transmit power to reduce their interference Co-channel interference of border users of adjacent cells or sectors, thereby increasing the data transmission rate of border users of cells or sectors; for users who are not easy to interfere with users in adjacent cells or sectors, the base station makes it The border user-specific resources of the zone have alternate use rights, or may increase their transmit power, so as to keep the total data transmission rate of the system without a significant drop.

因此，该用户u有权限使用的资源R(u)＝S(J(I₁))。在某一次实验中，当TTI_idx＝2时，J(I₁)＝1，J(I₂)＝2，J(I₃)＝3，由式(16)，式(17)，式(18)可得，该用户有权限使用的资源R(u)为：In Figure 13, when the user is located at position #1, the user has strong anti-interference ability and is easy to interfere with users in sector 2 and sector 3. According to formula (7),

Therefore, the resource R(u)=S(J(I ₁ )) that the user u has the right to use. In a certain experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18 ) can be obtained, the resource R(u) that the user has permission to use is:

R(u)＝{1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46} (20)

When the user is at position #2, the user has strong anti-interference ability and is easy to interfere with users in sector 2. According to formula (7), R(u)=S\(S(J(I ₁ ))∪S( J(I ₂ )))=S(J(I ₃ )). In a certain experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18 ) can be obtained, the resource R(u) that the user has permission to use is:

R(u)＝{3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48} (21)

When the user is at position #3 in Figure 13, the user has weak anti-interference ability and is easy to interfere with users in sector 3. According to formula (7), R(u)=S(J(I ₁ )). In a certain experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18 ) can be obtained, the resource R(u) that the user has permission to use is:

R(u)＝{1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46} (22)

When the user is located at position #4 in Figure 13, the user has strong anti-interference ability and is not easy to interfere with users in adjacent cells or sectors. According to formula (7), R(u)=S\(S(J( I ₁ ))), and has alternate access to S(J(I ₁ )). In a certain experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18 ) can be obtained, the resource R(u) that the user has permission to use is:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 2,5,8,11,14,17,20,23,26,29,32,35,38,41,44,47</span>}\\ \mathrm{<span\; class="notranslate">\; 3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48</span>}\end{array}\right\}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; twenty\; three</span>}<span\; class="notranslate">\; )</span>$

The resources that the user has alternate access rights to are {1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46}.

When the user is located at position #5 in Figure 13, the user’s anti-interference ability is weak, and it is not easy to interfere with users in adjacent cells or sectors. According to formula (7), S(J(I ₁ )), at a certain time In the experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18) can get , the resource R(u) that the user has permission to use is:

R(u)＝{1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46} (24)

When the user is located at position #6 in Figure 13, the user has strong anti-interference ability and is not easy to interfere with users in adjacent cells or sectors. According to formula (7), R(u)=S\(S(J( I ₁ ))), and has alternate access to S(J(I ₁ )). In a certain experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18 ) can be obtained, the resource R(u) that the user has permission to use is:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 2,5,8,11,14,17,20,23,26,29,32,35,38,41,44,47</span>}\\ \mathrm{<span\; class="notranslate">\; 3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48</span>}\end{array}\right\}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 25</span>}<span\; class="notranslate">\; )</span>$

The resources that the user has alternate access rights to are {1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46}.

To sum up, the result Φ of the user's permission to use resources is listed as follows:

(5) The base station allocates resources according to the user's authority to use resources

This step is located in the resource allocation module in FIG. 3 .

The base station executes a resource scheduling algorithm and allocates resources according to the result Φ of the user's right to use resources. In this embodiment, the proportional fairness algorithm of formula (9) is used for resource scheduling.

In Figure 13, when allocating resources, the base station (located in the sector identified as I ₁ in cell ①) first allocates resources S\S(J(I ₁ )) other than border user-specific resources, and then allocates border user-specific resources S(J(I ₁ )). In a certain experiment, when TTI_idx=2, J(I ₁ )=1, J(I ₂ )=2, J(I ₃ )=3, from formula (16), formula (17), formula (18 ) can be obtained, the resource numbers allocated by the base station first are {2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47} and {3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48}, the sequence number of resources allocated later is {1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46}. Specifically, the base station first allocates resources with sequence numbers {2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47} to the resources located in #4, The user of #6 allocates resources with sequence numbers {3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48} to #2, Users #4 and #6 finally allocate resources with sequence numbers {1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46} to the Users of #1, #3, #5. The above resource allocation order and allocation objects are listed as follows:

However, when there are surplus resources dedicated to border users and there are users with alternate use rights who still need resources, the base station will set the sequence numbers as {1, 4, 7, 10, 13, 16, 19, 22, 25, 28, Among the resources of 31, 34, 37, 40, 43, 46}, the unused resources are allocated to users with alternate usage rights, that is, users located in #4 and #6, so as to improve the spectrum reuse coefficient of the cellular system .

In the simulation, the scheme of increasing or reducing the user’s transmission power is not adopted. If the performance of the present invention needs to be further improved, for users with weak anti-interference ability and not easy to interfere with users in adjacent cells or sectors, the base station uses It increases the transmission power to obtain a higher data transmission rate. In Figure 13, the base station enables the user at position #5 to increase the transmission power to obtain a higher data transmission rate; for strong anti-interference ability and easy to interfere with neighboring cells or For the users in the sector, the base station reduces the transmission power to reduce the interference to adjacent cells or users in the sector. In Figure 13, the base station reduces the transmission power of the users in positions #1 and #2 to reduce the interference to the adjacent cells or users in the sector. Interference from users in adjacent cells or sectors.

(6) 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. 3 .

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 (12), and its parameters are: x=5, α=0.8, Pr _min =0.00001. 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", Qualcomm Europe (3GPP document, serial number: R1-061525, "Analysis of an SC-FDMA system with single-antenna transmission and multi-antenna reception in the uplink", Qualcomm Europe R&D Center) with the same curve.

In the simulation, the system adopts the method for reducing co-channel interference among users of the present invention and the non-interference suppression scheme and method (2) (the boundary user is defined as the path loss of the user to the cell or sector, the minimum 10% of the corresponding users) performance comparison. The simulation results are shown in the table below:

program serial number Program name Boundary user data rate (Kbps) (5% of users with the lowest data rate) Sector data rate (Mbps) 1 No interference suppression scheme 85 9.811 2 Method (2) 155 8.99 3 this invention 152 9.645

Simulation results show that the boundary user data rate of the present invention improves 78.8% than the non-interference suppression scheme, while the sector data rate only drops 1.7%; the sector data rate of the present invention improves 7.3% than method (2), and the boundary user data rate The rate fell only 1.9%. Therefore, the present invention has the advantages of higher boundary user data rate and higher overall system rate.

The method for reducing co-channel interference between users in the uplink FDMA cellular system proposed by the present invention assigns different resource usage rights to each user according to its anti-interference and interference with users in adjacent cells or sectors. For users in adjacent cells or sectors, the base station restricts the resources it is authorized to use, and may reduce its transmit power to reduce its co-channel interference to border users of adjacent cells or sectors, thereby improving the efficiency of the cell or the data transmission rate of the border users of the sector; for users who are not likely to interfere with users in adjacent cells or sectors, the base station makes it possible to use the resources dedicated to the border users of this cell or sector as a backup, or may increase its transmission power, to keep the total data transmission rate of the system from significantly decreasing, so when the present invention achieves the goal of reducing co-channel interference between users, it has the advantages of higher spectrum reuse coefficient, higher total data transmission rate of the system, and faster realization. Simple, less signaling interaction between the user and the base station. It has high application value in uplink FDMA cellular system.

The above specific embodiments of the present invention are merely examples for explaining the technical contents of the present invention. The present invention is not limited to the above-mentioned specific embodiments, which should not be interpreted in a narrow sense. It can be practiced with various changes within the spirit of the invention and the scope of the claims.

Claims (9)

1, a kind of method that reduces cochannel interference between the user of up FDMA cellular system is characterized in that, comprises the steps:

Step 1: each sub-district or sector mark off the boundary user private resource for boundary user wherein, and the boundary user private resource between assurance neighbor cell or sector does not have overlapping, and described boundary user private resource can be multiplexing by the non-boundary user in neighbor cell or the sector;

Step 2: the user monitors and detects the downstream signal that contains identification information of this sub-district or sector and neighbor cell or sector, obtains the detection information of downstream signal;

Step 3:, judge the anti-interference of user and the situation of disturbing user in neighbor cell or the sector according to the detection information of described downstream signal;

Step 4: the base station is according to the anti-interference of user and the situation of disturbing user in neighbor cell or the sector, the rights of using of Resources allocation;

Step 5: scheduling of resource is carried out, Resources allocation according to the rights of using of user to resource in the base station;

Step 6: the base station is carried out adaptive according to resource allocation result to user's up link;

In the described step 3, judge the anti-interference of user and the situation of disturbing user in neighbor cell or the sector, be meant: the user is made comparisons to the path loss values and the jamproof path loss threshold value of this sub-district or sector, if surpass threshold value, then this user is the strong user of antijamming capability, otherwise this user is the weak user of antijamming capability; The user is made comparisons with the path loss threshold value of disturbing user in neighbor cell or the sector to the path loss values of a plurality of neighbor cells or sector, if surpass threshold value, then this user is easy to disturb user in neighbor cell or the sector, otherwise this user is not easy to disturb user in neighbor cell or the sector.

2, the method that reduces cochannel interference between the user of up FDMA cellular system according to claim 1, it is characterized in that, in the described step 2, described detection information comprises: the identification information of sub-district or sector and user arrive the path loss values of this sub-district or sector.

3, the method that reduces cochannel interference between the user of up FDMA cellular system according to claim 1, it is characterized in that, in the described step 3, by the user according to described detection information, judge the anti-interference of user and the situation of disturbing user in neighbor cell or the sector, again judged result is reported to the base station.

4, the method that reduces cochannel interference between the user of up FDMA cellular system according to claim 1, it is characterized in that, in the described step 3, the user reports described detection information to the base station, according to described detection information, judge the anti-interference of user and the situation of disturbing user in neighbor cell or the sector by the base station.

5, the method that reduces cochannel interference between the user of up FDMA cellular system according to claim 1, it is characterized in that, for a little less than the antijamming capability and be not easy to disturb the user of user in neighbor cell or the sector, base station to make it promote transmitting power to obtain higher message transmission rate.

6, according to the method that cochannel between the user disturbs that reduces of the up FDMA cellular system described in the claim 1, it is characterized in that, strong and be easy to disturb the user of user in neighbor cell or the sector for antijamming capability, the base station makes it reduce transmitting power to reduce the interference to user in neighbor cell or the sector.

According to the method that cochannel disturbs between the user that reduces of claim 3 or 4 described up FDMA cellular systems, it is characterized in that 7, in the described step 3, described user periodically reports to the base station; Perhaps, described user with anti-interference be that trigger condition is reported to the base station with disturbing in neighbor cell or the sector user's situation to change.

8, the method that reduces cochannel interference between the user of up FDMA cellular system according to claim 1, it is characterized in that, in the described step 4, described Resources allocation rights of using, be meant: according to the judged result of described step 3, strong and be easy to disturb the user of user in neighbor cell or the sector for antijamming capability, surplus resources beyond the boundary user private resource of the boundary user private resource of if possible disturbed sub-district or sector and this sub-district or sector is not an empty set, then the base station makes its lack of competence use the boundary user private resource of disturbed sub-district of possibility or sector and the boundary user private resource of this sub-district or sector, and have authority to use described surplus resources, if described surplus resources is an empty set, then the base station makes it have authority to use the boundary user private resource of this sub-district or sector, and lack of competence is used the resource except that the boundary user private resource of this sub-district or sector; Strong and be not easy to disturb the user of user in neighbor cell or the sector for antijamming capability, the base station makes it that the resource of authority use except that the boundary user private resource of this sub-district or sector be arranged, and the boundary user private resource of this sub-district or sector is had the candidate rights of using; For a little less than the antijamming capability and be easy to disturb a little less than the user of user in neighbor cell or the sector and the antijamming capability and be not easy to disturb the user of user in neighbor cell or the sector, the base station makes it have authority to use the boundary user private resource of this sub-district or sector, and lack of competence is used the resource except that the boundary user private resource of this sub-district or sector.

9, the method that reduces cochannel interference between the user of up FDMA cellular system according to claim 1, it is characterized in that, in the described step 5, described scheduling of resource, be meant: at first, the resource allocation beyond the boundary user private resource in this sub-district is given the user who this resource is had rights of using in the base station, then, the boundary user private resource is distributed to the user who this resource is had rights of using in the base station, at last, the base station will be distributed to resource requirement to untapped boundary user private resource, and this resource be had the user of candidate rights of using.

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