WO2015106412A1

WO2015106412A1 - Discovery method for discovering device to device communication and terminal

Info

Publication number: WO2015106412A1
Application number: PCT/CN2014/070683
Authority: WO
Inventors: 张祺智
Original assignee: 华为技术有限公司
Priority date: 2014-01-15
Filing date: 2014-01-15
Publication date: 2015-07-23
Also published as: CN105309022B; CN105309022A

Abstract

A discovery resource time frequency allocation method and a terminal, wherein a discovery frame comprises m*n time frequency units, n is a number of time frequency units, m is a number of frequency domain units, n=p that is a prime number and m is a positive integer. The method comprises: the terminal transmitting a discovery signal on a first time frequency unit (i(0), j(0)) of a first discovery frame; and the terminal, based on the time frequency unit (i(0), j(0)), determining to transmit the discovery signal on a second time frequency unit (i(t), j(t)) of a tth discovery frame after the first discovery frame, wherein i(t)=(i(0)+k*t)mod m; j(t)=(j(0)+f(i(0))*b(t))mod p. According to a provided time frequency jump scheme, a UE collision rate in a time frequency jump cycle can reach 1/n. Therefore, the time frequency jump scheme is provided with a better discovery effect compared with a prior technical scheme.

Description

Discovery method and terminal for discovering end-to-end communication

The present invention relates to the field of mobile communication technologies, and in particular, to a method and a terminal for discovering end-to-end communication. Background technique

Device to Device (D2D) communication refers to a communication method that is directly performed between UEs with little or no dependence on the base station. D2D technology can reduce the burden on the macro network and increase the communication rate between UEs.

In order to achieve direct communication with each other, UEs must first discover each other. In the following cases: There are a large number of UEs in a certain range, and each UE needs to transmit a Discovery signal to let other UEs discover themselves. It is assumed that there are periodic Discovery frames in the system, and each Discovery frame contains m*n time-frequency units, that is, each Discovery frame is decomposed in time into n time-domain units, using j J={0, 1, . ..... , η-1 } indicates; each time domain unit can be divided into m frequency domain units according to the same regular frequency, and is represented by i 1={0, 1, . . . , ml }. Then, the i-th frequency domain unit on the jth time domain unit is the (i, j)th time-frequency unit. In each Discovery frame, each UE participating in the D2D Discovery can send a Discovery signal in a certain time-frequency unit for detection by other UEs. Generally, UEs that simultaneously send Discovery signals cannot hear each other. Therefore, in the transmission period of a Discovery frame, the Discovery signal in each frame sent needs to perform time-frequency jump, that is, each UE is in each Discovery. The time-frequency units that transmit the Discovery signal in the frame are different, so that each UE has a chance to be discovered by all other UEs.

The methods for realizing the time-frequency jump of the Discovery signal in the prior art include:

In a Discovery frame transmission period, each Discovery frame includes m*n time-frequency units, where n is the number of time-domain units, and m is the number of frequency-domain units, where n and m are positive integers; You can use (i ( * ), j ( * ) ) to identify each time-frequency unit in the Discovery frame, i (*) is the frequency domain position index of the time-frequency unit in the discovery frame; j (*) is the time domain position index of the time-frequency unit in the discovery frame. If a UE uses the time-frequency unit in the first Discovery frame as (i(0), j(0)), where the time-frequency unit of the first Discovery frame (i(0), j(0) ) is assigned by the base station or determined by the UE according to the principle of minimum energy. Then the time-frequency unit (i(t), j(tX) used in the tth Discovery frame is determined by:

i(t)=[i(0)+k*t ]mod m

j(t)= j(0)+mod(i(0) , n)*t+ floor(i(0)/n)*t*t ]mod n Equation 1

Where floor(x) is "rounded down", that is, takes the largest integer not greater than x; mod is the remainder, x mod y or mod (x, y) is the remainder of x divided by y;

For example: Set the number of frequency domain units m=6, the number of time domain units n=3, k=3. When the time-frequency jump is performed according to the above formula, the time-frequency units occupied by the UEs in each frame are as shown in Table 1:

Table 1

In Table 1 above, i (*) is represented by the vertical cell in Table 1, "*" takes a different value, so i (*) locates a different cell in the vertical cell, and the vertical cell The indexes are arranged from top to bottom and from small to large. j( * ) is represented by the horizontal cell in Table 1, "*" takes a different value, so j (*) locates the different cells in the horizontal cell, and the index of the horizontal cell is from left to Right, arranged in order from small to large.

For example: If a UE sends a discovery signal at the (t=0) Discovery frame at the time-frequency resource of "0", then (i(0), j(0))=(0, 0), substitute the formula:

i(t)=[i(0)+3*t]mod6 j(t)=L)(0)+mod(i(0), 3n)*t+ floor(i(0)/3)*t*t]mod 3

It takes (i(l), j(l))=(3, 0), so it jumps to the time-frequency position of the first (t=l) Discovery frames marked "0".

For a time-frequency hopping scheme, if there is a positive integer T such that the following condition (Q) holds, the scheme is said to be "column periodic"; the smallest positive integer T that satisfies the condition (Q) is called this time-frequency The "column period" of the jump scheme. Wherein the condition (Q) is:

For any two UEs that transmit a Discovery signal according to a time-frequency hopping scheme and any discovery frame t, if the two UEs simultaneously transmit a Discovery signal in the tth Discovery frame, they simultaneously send a Discovery in the t+T Discovery frames. signal.

If T is the column period of a time-frequency hopping scheme, then successive T Discovery frames are referred to as a "column variation period" of the time-frequency hopping scheme.

The maximum collision ratio of a time-frequency hopping scheme refers to: The maximum ratio of the number of collisions to the column period of a UE using two different initial Discovery resources in one column change period. Here "collision" means sending at the same time. Since terminals that simultaneously transmit Discovery signals cannot receive each other, a small collision ratio means more discovery opportunities. A small maximum collision ratio means that each pair of UEs has more chances of discovering each other.

According to the definition of the maximum collision ratio described above, the maximum collision ratio of the time-frequency jump scheme given by the above formula 1 is relatively large, so that the scheme of the time-frequency jump does not have a good effect. Summary of the invention

The embodiment of the present invention provides a method and a terminal for discovering a time-frequency allocation of a Discovery resource, which is used to solve the problem that the maximum collision ratio of the time-frequency hopping scheme provided in the prior art is relatively large, so that the scheme of time-frequency hopping does not work well. The problem with the effect.

In a first aspect, a method for discovering a time-frequency allocation of a Discovery resource is provided. The Discovery frame includes m*n time-frequency units, n is a number of time-domain units, and m is a number of frequency-domain units, where n=p is a prime number, and m is positive Integer; the method includes:

The terminal transmits a Discostery letter on the first time-frequency unit (i(0), j(0)) of the first Discovery frame. Number, where (i(*), j(*)) identifies each time-frequency unit in the Discovery frame, i ( * ) is the index of the frequency domain unit in the discovery frame; j ( * ) is the time domain unit in the discovery frame index;

Determining, by the time-frequency unit (i(0), j(0)), the second time-frequency unit (i(t), j(t)) of the t-th Discovery frame after the first Discovery frame Transmitting a Discery signal, where i(t) = ( i(0)+k*t ) mod m;

Mod represents the remainder, (i(0)+k*t) mod m represents the remainder obtained by dividing (i(0)+k*t) by m; k is a preset positive integer;

j(t)= (j(0)+f(i(0))*b (t)) modp;

f is a single shot from the whole frequency domain unit I to the r-dimensional row vector on F _P , ^ is a finite field containing p elements, b(t) is the upper r-dimensional column vector varying with t, and b (t) The period that varies with t is ^, where p = n is a prime number and r is a positive integer.

With reference to the first aspect, in a first possible implementation manner, the f satisfies the following condition: There is a positive integer q not greater than p, such that: for any one of the frequency domain units I, if q of i The hexadecimal representation is i=i. + i, * q ÷ ..... i,.^ * q^ ¹ , where r is the smallest positive integer not less than, -,··· ^_ ₁ is an integer between 0 and q-1;

Then the image of i under the single shot f is (i -.... _; U.

With reference to the first aspect, or the first possible implementation manner of the first aspect, in a second possible implementation manner, the b(t) takes all the vectors in a period that varies with t, Among them, is the vector space composed of the upper 1" dimension vector.

In conjunction with the second possible implementation of the first aspect, in a third possible implementation, successive r b(t) are linearly independent of _Fp .

With reference to the first aspect, or the first to third possible implementation manners of the first aspect, in a fourth possible implementation manner, the determining process of the column vector b(t) includes:

Take r irreducible polynomial f(x)=x ^r + ;κ-— ¹ +... + Satisfaction: There is no positive integer c smaller than “I”, so X. - ί is divisible by f(x) as a polynomial over F;

Let A be a friend matrix of f (X) 1 ■

■ i -:

- , ' -,

(Bu ' i , b is any arbitrary r-dimensional non-column vector; then: ^ a _dp ^† , that is, if t can be divisible, then "for all

0 vector; otherwise, b ( t ) is the vector calculated by the formula ( .3 0- * _b ) mod p.

In a first aspect, a terminal is provided, where the terminal includes:

An initial transmitting module, configured to transmit a Discery signal to other terminals on a time-frequency unit (i(0), j(0)) of the first Discovery frame, where the Discovery frame includes m*n time-frequency units, where n is The number of time domain units, m is the number of frequency domain units, where n = p is a prime number, m is a positive integer, and ( i ( * ), j ( * ) ) identifies each time-frequency unit in the Discovery frame, i ( * ) The index of the frequency domain unit in the discovery frame; j ( * ) is the index of the time domain unit in the discovery frame;

a real-time time-frequency unit confirmation module, configured to determine, according to the time-frequency unit (i(0), j(0)), a time-frequency unit of the t-th Discovery frame after the first Discovery frame (i(t), j( t)) emits a Discery signal, where i(t) = ( i(0)+k*t ) mod m; mod denotes the remainder, ( i(0)+k*t ) mod m denotes (i( 0)+k*t ) The remainder obtained by dividing m; k is a preset positive integer; j(t)= ( j(0)+f(i(0))*b ( t ) ) mod p ; f is a single shot from the whole frequency domain unit I to the upper r-dimensional row vector, is a finite field containing elements, b(t) is the upper r-dimensional column vector that varies with t, and b(t The period that varies with t is, where ρ = η is a prime number and r is a positive integer.

With reference to the second aspect, in a first possible implementation manner, the real-time time-frequency unit acknowledgment module determines the f by:

There is a positive integer q not greater than p such that: for any one of the frequency domain elements I, if the q-ary representation of i is i=i. + i, * q + * q^ ¹ , where r is the smallest positive integer not less than, and -, ··· ^_ ₁ is an integer between 0 and q-1;

Then the image of i under the single shot f is (i -.... _; U .

With reference to the second aspect, or the first possible implementation manner of the second aspect, in a second possible implementation manner, the real-time time-frequency unit confirmation module is further configured to determine that the b(t) varies with t And Take all the vectors in a cycle of change, where is ^! "Vector space composed of all the dimensions of the vector.

In conjunction with the second possible implementation of the first aspect, in a third possible implementation, the real-time time-frequency unit acknowledgment module is further configured to determine that consecutive r b(t) are linearly independent.

With reference to the second aspect, or the first to third possible implementation manners of the second aspect, in a fourth possible implementation, the process of determining, by the real-time time-frequency unit, the column vector b(t) includes: :

R taking the irreducible polynomial _{f (x) = + ¾ ^} - ί + satisfied: absence of less than - c i is a positive integer, such that ^ _ i is a polynomial f (x) divisible;.

A is a friend matrix of f ( X )

b is any arbitrary r-dimensional non-column vector; then _bp is if t can be divisible, then

0 vector; otherwise, b ( t ) is the vector calculated by the formula ( , d _P - i _h ) _mo dp .

The time-frequency hopping scheme provided by the present invention can achieve a UE collision ratio of 1/n in a time-frequency hopping period, so that it has a better time-frequency hopping effect than the prior art scheme. DRAWINGS

FIG. 1 is a schematic flowchart of a method for discovering a time-frequency allocation of a Discovery resource according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a terminal according to an embodiment of the present invention. Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is apparent that the described embodiments are a part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As shown in FIG. 1 , a method for discovering a time-frequency allocation of a Discovery resource according to an embodiment of the present invention is further described in detail below with reference to the accompanying drawings. The method specifically includes:

In the embodiment of the present invention, the Discovery frame includes m*n time-frequency units, n is the number of time domain units, and m is the number of frequency domain units, where n is a prime number, and m is a positive integer; when the communication system includes multiple And when the plurality of terminals communicate with each other through an end-to-end technology, each terminal in the communication system is configured to allow the other terminal to discover itself, on a time-frequency unit in the Discovery frame. Launching the Discovery signal, the method includes:

Step 101: The terminal transmits a Discery signal on the time-frequency unit (i(0), j(0)) of the first Discovery frame, where (i (*), j (*)) identifies each time in the Discovery frame. a frequency unit, i ( * ) is an index of a frequency domain unit in the discovery frame; j ( * ) is an index of a time domain unit in the discovery frame;

Step 102: The terminal determines, according to the time-frequency unit (i(0), j(0)), a time-frequency unit (i(t), j(t)) of the t-th Discovery frame after the first Discovery frame. Launching a Discery signal; where:

i(t) = ( i(0)+k*t ) mod m;

Mod represents the remainder, (i(0)+k*t) mod m represents the remainder obtained by dividing (i(0)+k*t) by m; k is a pre-set or positive integer configured by the base station ;

j(t)= ( j(0)+f(i(0))*b ( t ) ) mod n;

n=p is a prime number, f is a single shot from the whole frequency domain unit I to the upper r-dimensional row vector. It is a finite field containing p elements, and b(t) is a F _p that varies with t. The period of the r-dimensional column vector, and b(t) varies with t, where r is a positive integer.

According to the definition of the column period in the background art, the column period of the time-frequency jump scheme provided in FIG. 1 is | The single shot f from the whole frequency domain unit I to the F _p r-dimensional row vector can be defined as follows:

Take a positive integer q that is not greater than p. For any element i in the whole frequency domain unit I, if the q-ary representation of i is i=i. + ί _:1 * q + ...... ten i _r — * q ^r " ¹ , where r is the smallest positive integer not less than: g^m, ...-. is an integer between 0 and q-1;

Then the image of i under the single shot f is (H...-.., _ _± :). That is, f (i) is a q-ary representation of i, i = i ₀ + i _s = * q + i _r _j * q ^r_i .

Further, in order to minimize the number of times that any two UEs simultaneously transmit the Discovery signal in a change period of one column, the b(t) is required to take all the vectors in a period that varies with t, where It is a vector space composed of the F _p r dimensional vector. In the above manner, in any one column change period, any two UEs that use different initial resources to transmit a Discovery signal transmit a Discovery signal at most simultaneously in a column change period.

In addition, if the events that simultaneously transmit the Discovery signal are consecutively generated, the speeds detected by the terminals are mutually affected to some extent, so it is necessary to control the number of consecutive simultaneous transmissions of the two UEs. In order to control the number of consecutive simultaneous transmissions of two UEs, the b(t) should also satisfy: consecutive r 1) (3⁄4 in ? _: linearly independent.

If r consecutive b (t) linearly independent in F _p, then the two most r consecutive UE transmitted simultaneously. In a specific implementation, b (t) that satisfies the above conditions can be selected as follows:

Take, the last r times irreducible polynomial f(x)= a^- ¹ ...+ Satisfaction: There is no positive integer c less than -1, such that ^ - i is divisible by f(x) as the upper polynomial;

A is the friend matrix of f (X)

b is ^ any arbitrary n-dimensional non-column vector; let =| ^ a』 _P .

That is, if t can be divisible, let "be a full 0 vector; otherwise, let b (t) be the formula Oi. *b) In this embodiment, optionally, the (m, p) may take the values provided by the first column and the second column in Table 2, then r and f(x) correspond to the third and the third in Table 2. The contents shown in the four columns:

Table 2

The method provided by the embodiment, the following provides a detailed description of the method provided by the present invention by a specific example:

For example: m=6, n=p=3, k=3, take q=p=3, then r=2, take f(x)=x ² — x— J_ , then

A= f? ! ), let b= f! |, then the time-frequency jump scheme is

It)=[i(0)+3*t]mod6

That is: if t is divisible by 9, then

b(t) is a 0 vector; otherwise, it is written as a power of a square matrix multiplied by a column vector, and the result of the operation is a column vector (as shown in Table 3).

table 3

The time-frequency units occupied by the respective UEs calculated according to the above formula in each frame of a time-frequency hopping period are as shown in Table 4.

Table 4

It is easy to see that the tth Discovery frame has only a row change with respect to the t+9 Discovery frames without column changes. And any two UEs (for example, UE 0 and UE f) in the 0th Discovery frame to the 8th Discovery frame are simultaneously transmitted at most three times, so the maximum collision ratio is 1/3 (ie, l/n). On the other hand, any two UEs simultaneously transmit the Discovery signal at most 2 consecutive Discovery frames.

As shown in FIG. 2, according to the method shown in FIG. 1, the embodiment of the present invention further provides a terminal, where the terminal 200 includes:

The initial transmitting module 201 is configured to send a Discery signal to other terminals on the time-frequency unit (i(0), j(0)) of the first Discovery frame, where the Discovery contains m*n time-frequency units, n is the number of time domain units, m is the number of frequency domain units, where n = p is a prime number, m is a positive integer, and (i ( * ), j ( * ) ) identifies each time-frequency unit in the Discovery frame, i ( *) is the index of the frequency domain unit in the discovery frame; j (*) is the index of the time domain unit in the discovery frame;

The real-time time-frequency unit confirmation module 202 is configured to determine, according to the time-frequency unit (i(0), j(0)), a time-frequency unit of the t-th Discovery frame after the first Discovery frame (i(t), j (t)) emits a Discery signal, where i(t) = ( i(0)+k*t ) mod m; mod denotes the remainder, ( i(0)+k*t ) mod m Represents the remainder obtained by dividing (i(0)+k*t ) by m; k is a preset positive integer; j(t)= ( j(0)+f(i(0))*b ( t ) ) mod p; f is a single shot from the whole frequency domain unit I to the upper r-dimensional row vector, is a finite field containing elements, b(t) is the upper r-dimensional column vector varying with t, And the period in which b(t) varies with t is, where p=n is a prime number and r is a positive integer.

The real-time time-frequency unit confirmation module 202 determines the f by the following condition: a positive integer q that is not greater than p, such that: for any one element i of the frequency domain unit I, if the q-ary representation of i For i=i. + U * q + .....„.+ i _r _ * q ^{r_ i} , where r is not less than

1. _{§ 1} ^ The smallest positive integer, ΐ ί^...-..., ₅ , _ ₁ is an integer between 0 and q-1;

Then the image of i under the single shot f is (^ i^ -....., i _Y→ 3 .

Further, in order to minimize the number of times that any two UEs simultaneously transmit a Discovery signal in a change period of one column, the real-time time-frequency unit confirmation module 202 is further configured to determine that the b(t) varies with t All vectors in the pass are taken in one cycle of the change, where is the vector space composed of the F _p J r dimensional row vectors. In the above manner, during any change period of one column, any two UEs that use the different initial resources to transmit the Discovery signal simultaneously transmit the Discovery signal at most p ^r_i times in one column change period.

In addition, if the events that simultaneously transmit the Discovery signal are consecutively generated, the speeds detected by the terminals are mutually affected to some extent, so it is necessary to control the number of consecutive simultaneous transmissions of the two UEs. In order to control the number of simultaneously transmitting two consecutive UE, unit confirms said real frequency module 202 is also used to determine r consecutive b (t) linearly independent in F _p.

In a specific implementation, the process of determining the column vector b(t) by the real-time time-frequency unit confirmation module 202 includes:

Take ^ r times irreducible polynomial

X. _ai '- ^:i +... Ten Satisfaction: There is no positive integer c less than -1, such that X. - i is divisible by f(x) as a polynomial over F _:p ;

Let A be the f ( X ) friend matrix

b is any arbitrary r-dimensional non-column vector; ⁱ , that is, if t can be divisible, then b ( t ) is full

0 vector; otherwise, b ( t ) is the vector calculated by the formula (, 4 ^(tmd O- 2 * b ) mod p.

The foregoing one or more technical solutions in the embodiments of the present application have at least the following technical effects: Compared with the time-frequency hopping scheme in which the maximum collision ratio is greater than or equal to that provided by the prior art, the embodiment of the present invention provides The time-frequency hopping scheme can achieve a collision rate of 1/η in a time-frequency hopping period, so it has a better time-frequency hopping effect than the prior art scheme.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the division of each functional module described above is exemplified. In practical applications, the above-mentioned function assignment can be completed by different functional modules as needed. The internal structure of the device is divided into different functional modules to perform all or part of the functions described above. For the specific working process of the system, the device and the unit described above, reference may be made to the corresponding process in the foregoing method embodiments, and details are not described herein again.

In the several embodiments provided herein, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be used. Combined or can be integrated into another system, or some features can be ignored, or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form. The components displayed for the unit may or may not be physical units, ie may be located in one place, or may be distributed over multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application, in essence or the contribution to the prior art, or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and the like. The medium of the code.

The above embodiments are only used to describe the technical solutions of the present application in detail, but the description of the above embodiments is only for helping to understand the method and the core idea of the present invention, and should not be construed as limiting the present invention. Those skilled in the art will be able to devise variations or alternatives that are conceivable within the scope of the present invention.

Claims

Rights request

1. A discovery discovery resource time-frequency allocation method, characterized in that the Discovery frame contains m*n time-frequency units, n is the number of time domain units, m is the number of frequency domain units, where n=p is a prime number, m is a positive integer; the method includes:

The terminal transmits the Discoery signal on the first time-frequency unit (i(0), j(0)) of the first Discovery frame, where (i (*), j (*)) identifies each time-frequency unit in the Discovery frame unit, i (*) is the index of the frequency domain unit in the discovery frame; j (*) is the index of the time domain unit in the discovery frame;

The terminal determines according to the time-frequency unit (i(0), j(0)) to be in the second time-frequency unit (i(t), j(t)) of the t-th Discovery frame after the first Discovery frame. Emit Discoery signal, where, i(t) = (i(0)+k*t) mod m;

mod means taking the remainder, (i(0)+k*t) mod m means taking the remainder obtained after dividing (i(0)+k*t) by m; k is a preset positive integer;

j(t)= ( j(0)+f(i(0))*b ( t ) ) mod p;

f is an injector from the totality of frequency domain units I to the totality of r-dimensional row vectors on , ^ is a finite field containing p elements, and b(t) is F that changes with t. It is an r-dimensional column vector, and the period that b(t) changes with t is ^, where p=n is a prime number and r is a positive integer.

2. The method according to claim 1, characterized in that, the f satisfies the following conditions: There is a positive integer q no greater than p, such that: for any element i in the entire frequency domain unit I, if q of i The base representation is i=i. + i, * q + * q^ ¹ , where r is not less than

The smallest positive integer of 1 _¾ 1^, ― is an integer between 0 and q-1;

Then the image of i under the injective f is (i _s A -.― Λ- i ).

3. The method according to claim 1 or 2, characterized in that, b(t) takes all vectors in a cycle that changes with t, where, is an r-dimensional row on F _p A vector space composed of all vectors.

4. The method of claim 3, characterized in that consecutive r b(t) are linearly independent on .

5. The method according to any one of claims 1 to 4, characterized in that the column vector b(t) is indeed The determination process includes:

Taking the upper rth degree irreducible polynomial f(x)=f ten - ¹ eleven ten a satisfies: There is no positive integer c less than _P ^r ―, so that ^ - ί as the upper polynomial is divisible by f(x);

Let A be the friend matrix of f (X)

b is any r-dimensional non-zero column vector; then )

-■- =L(L

lA ^BI . 'c. , , ^if f ^r|t ,

mt ip. else, that is, if t can be divisible, then b (t) is a vector of all 0s; otherwise, b (t) is a vector calculated by the formula (¾, d — i * _{: b) rao£} ip.

6. A terminal, characterized in that the terminal includes:

The initial transmission module is used to transmit the Discoery signal to other terminals on the time-frequency unit (i(0), j(0)) of the first Discovery frame. The Discovery frame contains m*n time-frequency units, n is The number of time domain units, m is the number of frequency domain units, where n=p is a prime number, m is a positive integer, and (i

(*), j (*)) identifies each time-frequency unit in the discovery frame, i (*) is the index of the frequency domain unit in the discovery frame; j (*) is the index of the time domain unit in the discovery frame;

Real-time time-frequency unit confirmation module, used to determine the time-frequency unit (i(t), j() of the t-th Discovery frame after the first Discovery frame based on the time-frequency unit (i(0), j(0)) Discoery signal is emitted on t) ), where, i(t) = (i(0)+k*t) mod m; mod means taking the remainder, (i(0)+k*t) mod m means taking (i( 0)+k*t) is the remainder obtained after dividing by m; k is a preset positive integer; j(t)=

( j(0)+f(i(0))*b ( t ) ) mod p; f is an injector from the entire frequency domain unit I to the entire upper r-dimensional row vector, F _: contains p elements Finite field, b(t) is an upper r-dimensional column vector that changes with t, and the period of b(t) changing with t is p ^s ', where p=n is a prime number and r is a positive integer.

7. The terminal according to claim 6, wherein the real-time time-frequency unit confirmation module determines f according to the following conditions:

There is a positive integer q not greater than p, such that: For any element i in the total frequency domain unit I, if the q-base representation of i is i=i. + I, * q + ΐ _Γ _ ₁ * q ^r - S where, r is not less than The smallest positive integer of kj^m, υ^-. -... is an integer between 0 and q-1;

Then the image of i under the injective f is (i.A.,….. _t i _r→ .

8. The terminal according to claim 6 or 7, characterized in that the real-time time-frequency unit confirmation module is also used to determine all vectors in the b(t) pass within a period that changes with t. , where , is? ^^Up! "A vector space composed of all row vectors.

9. The terminal according to claim 8, wherein the real-time time-frequency unit confirmation module is also used to determine that r consecutive b(t) are linearly independent on F _p .

10. The terminal according to any one of claims 6 to 9, characterized in that the process of determining the column vector b(t) by the real-time time-frequency unit confirmation module includes:

Take the upper r degree irreducible polynomial f(x)=x ^r + ¾: ^- ¹¹ +…+ satisfies: There is no positive integer c less than P ^r ― i, such that i is divisible by f(x) as the upper polynomial;

matrix

b is any r-dimensional non-zero column vector; then = ( —^ _ρ , that is, if t can be divisible, then b ( is the total

0 vector; otherwise, b (t) is the vector calculated by the formula (^i ^O- 1 *b) modp.