WO2015078069A1

WO2015078069A1 - Frequency spectrum resource management method for d2d communications

Info

Publication number: WO2015078069A1
Application number: PCT/CN2013/089871
Authority: WO
Inventors: 田辉; 张平; 陈楠楠; 王智博
Original assignee: 无锡北邮感知技术产业研究院有限公司
Priority date: 2013-11-27
Filing date: 2013-12-18
Publication date: 2015-06-04
Also published as: CN103596182B; CN103596182A

Abstract

The present invention relates to the field of radio mobile communications, and provided is a frequency spectrum resource management method for D2D communications, which method particularly comprises: in the same cell, a plurality of pairs of D2D users communicating by using a frequency spectrum resource which is orthogonal to the frequency spectrum resource used by a cellular user; acquiring the amount of intra-frequency interference when every two pairs of D2D users conduct communications and interfere with each other; calculating the probability of communication interruption of each pair of D2D users when being interfered with by the intra-frequency interference; clustering the D2D user pairs according to the probability of communication interruption and the amount of the interference, distributing several frequency spectrum resources which are orthogonal to each other of the frequency spectrum resources used by the plurality of D2D users respectively to each cluster, with the same frequency spectrum resource being multiplexed by all the D2D user pairs in each cluster. The present invention can achieve multiplexing with low interference of a plurality of D2D users in the same cell under D2D communications to the same frequency spectrum resource.

Description

Spectrum resource management method in D2D communication

The present invention relates to the field of wireless mobile communications, and provides a spectrum resource management method in D2D communication. Background technique

With the advent of various new wireless services, people are increasingly demanding communication rates, and the spectrum resources that can be applied to wireless communication are very limited. It is necessary to provide a sufficiently high data communication rate in limited spectrum resources to satisfy users. Demand, improving spectrum utilization is very important. D2D (Device-to-Device) communication is a technology used in a cellular network to directly and short-range communication by multiplexing cellular spectrum resources under system control. Applying D2D technology to a cellular network can effectively increase local network throughput and improve spectrum utilization. However, when multiplexing cellular spectrum resources, the D2D receiver will be interfered by the same frequency. This phenomenon will greatly limit the full utilization of spectrum resources, so that spectrum resource management under D2D communication will optimize D2D and Cellular transmission is of great significance.

The spectrum resource management before ϊ3⁄4 can be roughly divided into three modes: spectrum allocation, power control and mode selection: detecting the degree of interference, and allocating small spectrum resources for D2D users; power control for D2D and cellular transmission links When the user's point-to-point transmission does not provide better system performance, mode switching is performed to allow the user to switch to cellular mode. Both of these schemes can optimize spectrum resource allocation and improve transmission quality while reducing interference.

However, the spectrum resource management schemes currently used are mostly for the one-to-one D2D transmission mode, that is, one spectrum resource is used by only one D2D user pair, and the spectrum resources used by different users are orthogonal to each other. This transmission mode has great limitations when the number of users in D2D is large, because the one-to-one format causes the number of spectrum resources to directly determine the number of users. On the other hand, the former scheme mainly considers the thousand between cellular and D2D users. If the D2D user pairs are multiplexed with the same spectrum resource, a large amount of the same frequency interference will occur, especially when a large number of co-channel interferences generated by a large number of users will make the transmission quality difficult to guarantee. Summary of the invention

(1) Technical problems solved

In view of the deficiencies of the prior art, the present invention provides a spectrum resource management method in D2D communication, which can be implemented. D2D communication is a low interference multiplexing of multiple pairs of D2D users in the same cell for the same spectrum resource.

(2) Technical plan

A spectrum resource management method in D2D communication, characterized in that the method comprises:

In the same cell, multiple pairs of D2D users use the spectrum resources of the spectrum resources used by the cellular users to communicate with each other; and acquire the interference of the same frequency interference that each pair of D2D users receive during communication;

Calculate the probability of communication interruption when each pair of D2D users are subjected to co-channel interference;

And dividing the D2D user pair according to the communication interruption probability and the interference amount, and assigning, to each cluster, each of the clusters of the spectrum resources used by the plurality of pairs of D2D users All D2D user pairs within a cluster are multiplexed with the same 'spectral spectrum resources.

Preferably, after all of the steps further comprising reducing intra-cluster co-channel interference by power control of D2D users within the same cluster"

Advantageously, said performing power control comprises determining an optimum transmission power by deriving a power optimization function inversely proportional to the transmission power proportional to the probability of successful transmission based on said communication outage probability.

Preferably, the clustering the D2D user pair according to the communication interruption probability and the interference amount comprises: obtaining a maximum user log number that each cluster can accommodate according to the communication interruption probability; the clustering has to be satisfied Restrictions include the number of D2D user logs less than or equal to the maximum user log „

Preferably, the communication constraint probability that the D2D user must satisfy the clustering step according to the communication interruption probability and the interference amount is smaller than a certain criterion for each D2D user pair in the cluster. Threshold.

Preferably, the D2D user pair clustering according to the communication interruption probability and the interference amount further includes: Step T1: All D2D user pairs are classified into the same user group;

Step T2 _: calculating, in the user group, a sum of the interference amounts of each pair of D2D users to all other D2D user pairs according to the interference amount;

Step Τ3: Arrange all D2Dffl households in descending order according to the sum of the thousands of disturbances;

Step T4: If the number of D2D user pairs in the current user group is greater than the maximum user logarithm, the D2D user pair whose sum of the interference amounts is the most fired is removed, and the process returns to step T2 to repeat the question. The number of D2D user pairs in the current user group is not greater than the maximum user logarithm;

Step T5 _: divide all D2D user pairs in the user group into a new cluster at this time, and clear the user group;

Step 6: If the remaining number of deleted D2D user pairs is greater than the maximum user logarithm, then the D2D user pairs are classified into the user group, and return to step Τ2, repeating the steps between: The remaining number of deleted D2D users is not greater than the maximum number of users; Step T7 _: Divide the remaining D2Dff1 households that are removed at this time into a new cluster.

(3) Beneficial effects

The present invention has the following beneficial effects:

In the present invention, the interrupt probability is a parameter describing the probability of successful communication, so that the maximum user logarithm that can be accommodated in a cluster can be defined according to the threshold setting of the communication success rate; under the condition of the maximum user logarithm limit, The D2D user pair can be clustered according to the amount of interference, the user with less interference is divided into the same cluster, and the user with larger interference is divided into different clusters, and the D2D in the same cluster is made. The user multiplexes the same spectrum resource, and the D2D user pairs between different clusters multiplex the spectrum resources orthogonal to each other, thereby realizing low-interference multiplexing of multiple pairs of D2D users for the same spectrum resource.

It should be noted that the acquisition of the interference amount is a link detection step for obtaining the same-frequency interference situation before clustering, and it does not mean that all D2D user pairs always use the same spectrum resource for communication. After the clustering is completed according to the same-frequency interference condition, different clusters are allocated resources orthogonal to each other according to the clustering situation.

In the clustering method, D2D users with large interferences S are excluded from other D2D users, and the number of user pairs is not less than the logarithm of the most fired users; then these D2D user pairs are divided into one cluster, thereby At this time, the same frequency interference between the remaining D2D user pairs in the cluster will be relatively small. Then repeat this operation for ungrouped D2D users to achieve the purpose of reducing interference. On the other hand, the introduction of the largest user logarithm is also to make the intra-cluster interference as small as possible, including:

First, because the amount of interference is not less than 0, each additional 'user pair' in the cluster will inevitably cause interference to the user pairs in other clusters. Therefore, to maximize the sum of interference between different clusters, The cluster contains as many user pairs as possible.

Then, if the sum of the ten disturbances between different clusters reaches the maximum, the amount of disturbance in the cluster will be minimized. Because if there is a user pair ₃ in the cluster A of the full user pair, the sum of the interferences with other users is R1, and the other cluster B has a user pair b, and the cluster A has a user pair other than a. The sum of the thousands of disturbances is 2, and R1 is greater than R2. To maximize the sum of the interferences between different clusters, divide a into B and divide b into A. By repeating this - - process, all pairs of users with a small amount of interference of 3⁄4 will be concentrated in cluster A. The same process is performed for each cluster, so when the sum of the interference amounts between the two pairs of D2D users between different clusters is the largest, the amount of interference inside all clusters is the smallest.

Based on the two points of h, to minimize the amount of interference inside the cluster, it is necessary to accommodate as many user pairs as possible within each cluster, and even if the number of D2D users in the cluster is as large as possible, the maximum number of users is reached.

Through the division of clusters, the present invention determines which D2D user pairs can use the same spectrum resources and achieve a lower amount of interference, that is, achieves low-interference multiplexing of multiple pairs of 'D2D users for the same spectrum resource. Thus, compared to the one-to-one transmission mode, the same spectrum resource can accommodate more D2D users under the condition that the interference is sufficiently small. Yes, it has a larger throughput than the single D2Dff1 household, and a higher spectrum resource utilization.

It is not necessary to achieve all of the advantages described above at the same time to implement any of the products or methods of the present invention. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the ft diagrams required in the embodiments or the prior art description will be briefly described. Obviously, the drawings in the following description It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a flowchart of a spectrum resource management method for a D2D communication port according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a user cluster under D2D communication in an embodiment of the present invention.

The specific embodiments of the present invention will be further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

The present invention provides a spectrum resource management method in a D2D signaling. Referring to FIG. 1, the method includes: Step S1 _{: In a} same cell, multiple pairs of D2D users use spectrum resources orthogonal to spectrum resources used by cellular users. Communication

Step S2 _: Acquire a perturbation amount of the same frequency interference that each pair of D2D users receive during communication; Step S3: Calculate a communication interruption probability when each pair of D2D users is subjected to the same frequency interference;

Step S4: Clustering the D2D user pair according to the communication interruption probability and the interference quantity, and assigning, to each cluster, a spectrum resource of thousands of copies of the spectrum resources used by the plurality of pairs of D2D users Each allocation - share, all within each cluster

D2D users reuse the same spectrum resource.

Specifically, the method includes:

When the number of D2D users is relatively large, multiplexing the cellular user resources one by one will cause a large interference to the cellular transmission. To this end, resources are introduced. The D2D transmission mode of the iT is exchanged; that is, the same resources can be reused among the D2D users, but Hand in with cellular user resource E. In this case, cellular transmission is not affected, and the interference control between D2D users is mainly considered.

Then, the interference amount of the same-frequency interference that is received by each of the two pairs of D2D users during communication can be obtained by link detection, or measured according to a certain process in the initialization phase, and details are not described herein again.

Obtain the break rate expression of the D2D receiving user under the same frequency interference:

It is assumed here that the single cell radius is its coverage to indicate that the distribution of W to D2D users is obeyed. The parameter is a Poisson distribution of A, and its transmission power is . Then the D2D user log halo is 2Ω, and the user distribution probability is _; Ρ{Ν = «} = e ^Λ 3⁄4 . The channel gain consists of Rayleigh fading and shadow fading obeying the lognormal distribution. The D2D user obeys the prime frequency interference of the remaining D2D user pairs, if the λ D2D link receives the ith D2D chain. The same frequency perturbation of the road is _fl , and its probability density function is

./ ¹³ ) :——"^————) (1) Its towel! Indicates the average received power of the first 020 pair, and 3⁄4 indicates the link gain of the D2D link when multiplexing the first spectrum resource. .

When D2D pairs i and λ are transmitted on the "channel resources", the link length of the first D2D pair and the receiving user of the i-th D2D pair and the accepting user of the first D2D pair are respectively represented by /3⁄4, 13⁄4. The distance, to represent the 0 mean, the normalized normal distribution probability density function of the unit variance, respectively represents the path loss index and the lognormal standard deviation, and the probability density of the link attenuation is:

1 hi 3⁄4 -- l _n (3⁄4" )

Ex j (2)

Γ1πσί ι

When multiple D2D pairs transmit information on the "channel", the received signal-to-noise ratio of the first D2D user pair can be expressed as follows, which is the noise intensity.

When the received signal to noise ratio is less than the expected value Y _g6i , the link transmission is considered to be interrupted. To indicate the signal power and interference power received by the current D2D link, respectively, the link outage probability can be expressed as follows:

~ Pr[F _B > Y _lmt JR + N ₀ )] = l -cxp - 1 - «ρ(- ί «ρ ( 3⁄4) - S(x ₀ ))

It can be seen that the more the number of user logs H multiplexing the same resources, the greater the interference received by the D2D transmission link, and the greater the probability of interruption.

The D2D user pair is clustered according to the limitation of the user target tear rate, and the same resource is reused by the terminal in the same cluster. Reusing orthogonal resources in different clusters;

The target outage probability is / ^ To satisfy _Ακί <ρ, the maximum user density l _{max of the} same resource can be obtained by (4), and the corresponding user pair number Λ^==Α ^∞Χ Ω , Ω _Λ denotes a small Κ range.

The present invention regards D2D user pairs multiplexing the same resources as being in the same cluster, and thus resource allocation management can be realized by dividing users into different clusters, assuming that the user moves little during the communication process of the D2D users. The effect on cluster partitioning can be ignored. The number of users per cluster is up to the maximum number of users V ^m « , which multiplexes the same channel resources. The division of clusters should aim at minimizing co-channel interference between users, that is, user pairs with large mutual interference are not in the same cluster, and multiplexing: lE intersects spectrum resources for information transmission.

At this point, the forbidden division can be transformed into the maximum cut problem of ffl. The D2D user pair is represented as a graph G=( ,?), the point set F is composed of .D2D pairs, and each edge of the edge set E is connected with two different D2D pairs, with the same frequency interference between the user pairs as different clusters. The link weight of the internal user pair, that is, _3⁄4 indicates the amount of interference between the D2D pair and /, the mutual interference. Our standard is to divide a D2D user pair into different clusters, so that the inter-frequency interference of the user pairs in the same cluster is relatively small, and the interference between users in adjacent clusters is relatively large. By allocating different resources for different cluster users, frequency utilization can be improved while avoiding large interferences, and overall transmission efficiency is optimized. Assume that the final set of graph points is divided into M ( ≥ 2) parts, each part is cluster = ··,.Μ. Then the clustering problem is:

U3⁄4, = (5)

m=l

The Heuristic algorithm is applied to obtain a suboptimal solution to the problem. The algorithm steps are as follows:

Step 1 _{: Pout} <p, calculate and W. The number of initialization clusters is 1, including all D2D users ^ ie M = l,

Step 2; Set --- - '3⁄4 user group g, _ra = M

Step 3: 4 indicates the interference of the D2D user to other D2D user pairs in the cluster.

^=W1 ∑_ " ^{Vk e Z} « «The towel| , I means the number of users of the collection towel. Calculate 4, * = ■■ -K in turn, and arrange them in descending order to form the set Ω

Step 4: If | |> , V' selects the largest user pair, removes the user from the current cluster, assigns it to the newly set user group g, and returns to step 3 to recalculate the interference. Sort descending, and remove the next pair of D2D users with the largest interference when | , |>]¥, until the number of users in all clusters before 3 is small. Τ·Λ'"« The newly set user group g is the newly added cluster, M=M+ for the cluster, return to step 2, re-do the same operation on the cluster, and get the most The number of users in the next cluster is not greater than.

Step 5: Μ indicates the number of clusters, and allocate channel resources for the clusters that have been divided:

It indicates the transmission rate of the user in the cluster _w to occupy the channel resource when performing data transmission.

In this way, the clustering method which makes the total transmission rate the most popular is obtained, wherein the interrupt rate of each user is made smaller than the set threshold by limiting the number of intra-frequency users.

In-step to reduce intra-cluster intra-frequency interference, power control of intra-cluster transmission.

Users in the same cluster reuse the same resources for data transmission. Through the resource allocation analyzed in S3, the user's interrupt rate can be within the acceptable target range. As the transmission power of the D2D link increases, the link interruption rate decreases, and correspondingly increased interference is generated for the remaining intra-frequency users. Therefore, the transmission power of D2D has its own success rate and the distortion of the interference between the remaining users. When the transmission interruption rate is not less than a predetermined value, power control can reduce the interference and energy loss and improve network performance.

In order to determine the transmission power of the compromise, the network proposes a power optimization function.

It can be seen that the function decreases as the probability of transmission interruption increases, and as the transmission power of the user increases, we select the optimal transmission power to obtain the maximum energy utilization to reduce the interruption rate. Express

' where m

Under the premise of ensuring the transmission quality, the transmission power is minimized, then the problem can be expressed as: max Z -- max p, /Q\ its towel, function ² is continuous in the domain (o, +oo), so it can be deviated Guide the above |3⁄4 questions,

^ = ^ ¹ - ^ ( _{Λ + ί 3⁄4} = 0 no)

The invention provides a method for managing interference of D2D communication, which comprises resource allocation and power control of all D2D terminals in a single cell. To improve spectral efficiency, multiple D2D pairs can reuse the same spectrum resource. Users are clustered, users in the same cluster reuse the same spectrum resources, and users in different clusters use the spectrum resources of each other to reduce strong interference. At the same time, in order to further reduce the same-frequency interference, power control is performed on users in the same cluster to achieve a compromise between the interrupt rate and the reduced energy, and finally optimize the reliability of the D2D transmission.

It should be noted that, in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply such entities or operations. There are any such actual relationships or sequences, and the term "including", "including" or any other variant thereof is intended to encompass a non-exclusive inclusion, such that a process, force-method, article or device comprising a series of elements Not only those elements, but also other elements that are not explicitly listed, or elements that are inherent to such a process, method, item, or device. Without further restrictions, the statement "includes a... "Definitive elements do not exclude the presence of additional identical elements in a process, method, article, or device that includes the elements.

The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to be limiting; although the present invention will be described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still The technical solutions contained in the examples are modified or equivalently replaced with some of the technical features; and the modifications or substitutions do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

claims

1. A spectrum resource management method in D2D communication, characterized in that the method includes:

In the same cell, multiple pairs of D2D users communicate using spectrum resources that overlap with the spectrum resources used by cellular users; Obtain the co-frequency interference that each pair of D2D users receive when communicating;

Calculate the communication interruption probability of each pair of D2D users when they are subject to co-channel interference;

Divide D2D users into clusters according to the communication interruption probability and the interference amount, and allocate a share of orthogonal spectrum resources among the spectrum resources used by the multiple pairs of D2D users to each cluster. All D2D user pairs in a cluster reuse the same spectrum resources.

2. The method according to claim 1, characterized in that, after all the steps, the step further includes reducing intra-cluster co-frequency interference by performing power control on mo users in the same cluster.

3. The method according to claim 2, wherein the performing power control includes calculating a power optimization function that is proportional to the probability of successful transmission and inversely proportional to the transmission power according to the communication interruption probability. The optimal transmission power can be obtained using the derivation method.

4. The method according to claim 1, characterized in that dividing D2D users into clusters according to the communication interruption probability and the interference amount includes:

The maximum number of user pairs that each cluster can accommodate is obtained according to the communication interruption probability; the restriction conditions that the clustering must satisfy include that the number of D2D user pairs is less than or equal to the maximum number of user pairs.

5. The method according to claim 1, characterized in that the restriction conditions that must be met in the step of dividing D2D users into clusters according to the communication interruption probability and the interference amount include each D2D user in the same cluster. The probability of communication interruption between user pairs is less than a certain specified threshold.

6. The method according to claim 4, characterized in that: T, the dividing D2D households into clusters according to the communication interruption probability and the interference amount further includes:

Step T1: Put all D2D user pairs into the same user group;

Step T2 _: Within the user group, calculate the sum of the interference amount of each pair of D2D users to all other D2D user pairs according to the interference amount;

Step T3; Arrange all D2D user pairs in descending order according to the sum of the interference amounts;

Step T4: If the number of D2D user pairs in the current user group is greater than the maximum number of user pairs, remove the D2D user pair with the largest sum of interference amounts, and return to step T2 to repeat this process. Steps until the number of D2D user pairs in the current user group is not greater than the maximum number of user pairs;

Step T5: Divide all D2D user pairs in the user group at this time into new clusters, and clear the users Group;

Step T6: If the number of remaining removed D2D user pairs is greater than the maximum number of user pairs, then classify these D2D user pairs into the user group, return to step T2, and repeat the steps in between until the remaining The number of removed D2D user pairs is not greater than the maximum number of user pairs;

Step T7 _: Divide the remaining removed D2D user pairs into a new cluster.