CN116390054A - V2V multicast communication minimum-maximum decoding error rate resource allocation method - Google Patents

Abstract

The invention discloses a method for resource allocation of minimum-maximum decoding error rate in V2V multicast communication, which includes: respectively acquiring system parameters of the Internet of Vehicles system and the first channel environment in front of each terminal in the target V2V multicast group in the Internet of Vehicles system parameter, and the current second channel environment parameter and the first transmission parameter of the V2I user end using the same communication resources as the target V2V multicast group in the vehicle networking system; the target V2V multicast group includes a transmitting end and multiple receiving ends; according to the first A channel environment parameter, a second channel environment parameter, a first transmission parameter, a system parameter, a preset transmission parameter and a preset convergence threshold, and multiple sets of transmission parameters are obtained through an optimization method; each set of transmission parameters includes a transmission code length and a first Two transmission parameters; select a set of transmission parameters from multiple sets of transmission parameters, as the optimal transmission parameters of the transmitting end when the transmitting end communicates with multiple receiving ends; in the decoding error rate of each receiving end under the optimal transmission parameters The maximum decoding error rate is the smallest.

Description

A Min-Maximum Decoding Error Rate Resource Allocation Method for V2V Multicast Communication

technical field

The invention belongs to the technical field of wireless communication, and in particular relates to a minimum-maximum decoding error rate resource allocation method for V2V multicast communication.

Background technique

NR-V2X supports wireless communication between vehicles and surrounding things, realizes intelligent information exchange and sharing, and has advanced application functions such as collaborative automatic driving, complex environment perception, and intelligent traffic control. The common forms of vehicle communication connections include vehicle to vehicle (Vehicle to Vehicle) Vehicle, V2V), Vehicle to Infrastructure (V2I) Interaction has strict requirements on latency and reliability; V2I supports frequent access to networks and servers through high-capacity communication links, and is generally used for long-packet data tasks such as content sharing and media streaming.

As a special enhancement technology of Rel-16 and a key driving technology of intelligent transportation system, the V2V multicast technology of Internet of Vehicles can further enhance traffic safety, improve the quality of vehicle coordination, and promote the development of multiple transportation functions. V2V communication is usually applied to delay-sensitive safety-critical information transmission business in URLLC scenarios, and periodically sends safety service notification information (such as vehicle driving information such as positioning, speed, acceleration, collision warning information, etc.) to surrounding vehicle users. This can provide enough reaction time for drivers to make timely decisions on road conditions, especially in public safety services such as school buses and ambulances, where V2V multicast communication is a required function.

NR-V2X supports more flexible transmission modes, including multicast mode in addition to unicast and broadcast. In security or control scenarios, compared with broadcasting, multicasting is more effective and reliable in reducing redundancy; compared with unicasting, multicasting saves energy and improves spectrum utilization. But at the same time, research on NR-V2X multicast is far less than unicast, and there are still many challenges in multicast transmission methods in NR-V2X scenarios. In safe driving scenarios, 3GPP plans to transmit a 32-byte code length, which meets at least 99.9% reliability. To meet stringent QoS requirements, resource allocation to V2V multicast groups must be done using short-packet data communication theory, which makes the resource allocation problem highly non-convex and computationally challenging.

Most of the existing low-latency and high-reliability scenarios of the Internet of Vehicles are based on V2V unicast requirements for resource allocation, which makes the effectiveness and reliability of multicast low.

Contents of the invention

In order to solve the above-mentioned problems in the related art, the present invention provides a method for resource allocation of minimum-maximum decoding error rate in V2V multicast communication. The technical problem to be solved in the present invention is realized through the following technical solutions:

The present invention provides a minimum-maximum decoding error rate resource allocation method for V2V multicast communication, including:

Respectively acquire the system parameters of the Internet of Vehicles system, the first channel environment parameters corresponding to each terminal in the target V2V multicast group in the Internet of Vehicles system, and the same communication used by the Internet of Vehicles system and the target V2V multicast group The second channel environment parameter and the first transmission parameter currently corresponding to the V2I user terminal of the resource; the target V2V multicast group includes one transmitting terminal and multiple receiving terminals;

According to the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the system parameter, the preset transmission parameter and the preset convergence threshold, multiple sets of transmission parameters are obtained through an optimization method; each set The transmission parameters include a candidate transmission code length and a candidate second transmission parameter;

Selecting a set of transmission parameters from the multiple sets of transmission parameters as the optimal transmission parameters of the transmitting end when the transmitting end communicates with the plurality of receiving ends; wherein, under the optimal transmission parameters, Among the decoding error rates of the respective receivers, the maximum decoding error rate is the smallest.

In some embodiments, the selecting a set of transmission parameters from the multiple sets of transmission parameters as the optimal transmission parameters of the transmitting end when the transmitting end communicates with the plurality of receiving ends currently includes:

Determining the maximum decoding error rate among the decoding error rates of each receiving end under each set of transmission parameters, and obtaining a plurality of maximum decoding error rates corresponding to the multiple sets of transmission parameters one-to-one;

A set of transmission parameters corresponding to a minimum value among the plurality of maximum decoding error rates is used as the optimal transmission parameter.

In some embodiments, the system parameters include a first parameter and a second parameter; the optimization method includes a coordinate descent method; A transmission parameter, the system parameter, a preset transmission parameter and a preset convergence threshold, and multiple sets of transmission parameters are obtained through an optimization method, including:

According to the first parameter, determine the first constraint condition of the first preset optimization function and the second constraint condition of the second preset optimization function; the preset optimization function is used to represent the decoding error rate, signal-to-noise ratio, transmission code the relationship between the length and the second emission parameter;

Using the preset transmission parameter as an initial second transmission parameter, according to the initial second transmission parameter, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission Parameters, the preset convergence threshold, the first preset optimization function, the first constraint condition, the second preset optimization function and the second constraint condition, the transmission code is performed by the coordinate descent method Long and multiple iterations of the second transmission parameter to obtain the intermediate transmission code length;

According to the intermediate transmission code length, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second preset optimization function and the second constraints to obtain the multiple sets of transmission parameters.

In some embodiments, according to the initial second transmission parameter, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the preset The convergence threshold, the first preset optimization function, the first constraint condition, the second preset optimization function and the second constraint condition, the transmission code length and the second transmission parameter by the coordinate descent method Multiple iterations of to get the intermediate transmission code length, including:

At the time of the t iteration, the second transmission parameter obtained in the t-1 iteration is obtained, and the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter and the second transmission parameters obtained in the t-1th iteration are substituted into the first preset optimization function, and the first preset optimization function is solved according to the first constraint condition to obtain the transmission of the tth iteration code length; t is an integer greater than or equal to 1, and when t is 1, the second transmission parameter obtained in the t-1th iteration is the initial second transmission parameter;

Substituting the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, and the transmission code length obtained by the t-th iteration into the second preset optimization function, And solving the second preset optimization function according to the second constraint condition to obtain the second transmission parameter of the t-th iteration;

According to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second transmission parameter and the transmission code length obtained in the t-1th iteration, and the tth The second transmission parameter and the transmission code length obtained by the second iteration determine respectively the decoding error rate of the t-1th time and the decoding error rate of the tth time of each receiving end;

Calculate the t-th objective function value according to the maximum decoding error rate in the t-1 th decoding error rate and the t-th decoding error rate in the maximum decoding error rate;

When the t-th objective function value is less than or equal to the preset convergence threshold, the iteration ends, and the transmission code length of the t-th iteration is used as the intermediate transmission code length.

In some embodiments, the second transmission parameter obtained according to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, and the t-1th iteration and the transmission code length, as well as the second transmission parameter and the transmission code length obtained in the tth iteration, respectively determine the decoding error rate of the t-1th time and the decoding error rate of the tth time of each receiving end, including:

Calculate and determine according to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, and the second transmission parameter and transmission code length obtained in the t-1th iteration The decoding error rate of the t-1th time of each receiving end;

According to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, and the second transmission parameter and transmission code length obtained in the tth iteration, calculate the The decoding error rate of the tth time.

In some embodiments, according to the maximum decoding error rate in the decoding error rate of the t-1th time and the maximum decoding error rate in the decoding error rate of the tth time, the calculation of the first The objective function value of t times, including:

Making a difference between the maximum decoding error rate in the decoding error rate of the t-1th time and the maximum decoding error rate in the decoding error rate of the tth time to obtain a difference;

The ratio between the obtained absolute value of the difference and the maximum decoding error rate among the decoding error rates of the t-1th time is used as the objective function value of the tth time.

In some embodiments, according to the intermediate transmission code length, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second preset Assuming an optimization function and the second constraint condition, the multiple sets of transmission parameters are obtained, including:

Rounding down the intermediate transmission code length to obtain an integer;

using the integer and adjacent integers of the integer as candidate transmission code lengths;

Substituting each candidate transmission code length, the second parameter, the first channel environment parameter, the second channel environment parameter, and the first transmission parameter into the second preset optimization function, and according to the The second constraint condition is to solve the second preset optimization function to obtain a candidate second transmission parameter corresponding to each candidate transmission code length;

Each candidate transmission code length and a corresponding candidate second transmission parameter are used as a set of transmission parameters to obtain the multiple sets of transmission parameters.

In some embodiments, the first preset optimization function is:

The first constraint condition is:

为正整数，m为传输码长，D为预设安全信息数据包大小，M_min为传输码长下限值、M_max为传输码长上限值，ε_max为预设最大译码错误率。Wherein, ε _n,i is the decoding error rate of the i-th receiver, i=1,2,...,A, A is the total number of receivers in the target V2V multicast group, γ _n,i (P _n ) is the SNR of the i-th receiving end, V _n,i (P _n ) is the channel dispersion of the i-th receiving end, Q(.) is a Gaussian function, P _n is the second transmission parameter,

is a positive integer, m is the transmission code length, D is the preset security information packet size, M _min is the lower limit of the transmission code length, M _max is the upper limit of the transmission code length, and ε _max is the preset maximum decoding error rate .

In some embodiments, the second preset optimization function is:

The second constraint condition is:

Wherein, P _n,max is the preset maximum second transmission parameter, γ _max is the preset maximum signal-to-dry ratio, and E _tot is the preset total energy consumption of the system.

The present invention has the following beneficial technical effects:

By optimizing the transmission parameters and communication code length, the maximum decoding error rate of the V2V multicast group can be minimized, so that the information of the transmitter can be transmitted to multiple receivers accurately and timely, thereby improving the reliability and effectiveness of multicast, and improving traffic safety.

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Description of drawings

FIG. 1 is a model diagram of an exemplary V2V multicast network provided by an embodiment of the present invention;

FIG. 2 is a flow chart of a method for V2V multicast communication minimum-maximum decoding error rate resource allocation method provided by an embodiment of the present invention;

Fig. 3 is an exemplary data packet information amount provided by an embodiment of the present invention, and a comparison diagram of the impact relationship between the number of receiving ends on the decoding error rate;

FIG. 4 is a comparative diagram of the relationship between exemplary vehicle speed and the number of receiving terminals on the decoding error rate according to an embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with specific examples, but the embodiments of the present invention are not limited thereto.

In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

Although the present invention has been described in conjunction with various embodiments herein, in the process of implementing the claimed invention, those skilled in the art can understand and Other variations of the disclosed embodiments are implemented. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that these measures cannot be combined to advantage.

At present, most of the existing low-latency and high-reliability scenarios of the Internet of Vehicles are based on resource allocation based on V2V unicast requirements. However, the minimum decoding error rate achievable by a V2V multicast group depends on the decoding error rates of all receivers in the group, and it is necessary to consider the situation of the worst receiver to ensure the effectiveness and reliability of multicast. For this reason, the present invention provides A minimum-maximum decoding error rate resource allocation method for V2V multicast communication.

Fig. 1 is a model diagram of an exemplary V2V multicast network provided by an embodiment of the present invention. As shown in Fig. 1 , the IoV system includes a base station gNB, a V2V multicast group and multiple V2I clients. The V2V multicast group includes a transmitting terminal n and A (for example, 4) receiving terminals a, and the gNB is located on the roadside of the expressway. The transmitters and receivers at the transmitter, receiver, and user end are all equipped with a single antenna, and the V2V multicast group multiplexes V2I uplink resources. The system adopts time division multiple access as the media access control protocol. The transmitter in the V2V multicast group needs to transmit data to the receiver in the multicast group within τ=M _max T _s seconds, where T _s =1/B Represents a symbol duration, B represents the system bandwidth, and M _max represents the maximum number of symbols allowed for data transmission. The channel is quasi-static for the duration of m symbols sent from the V2V transmitter to the receiver. The method provided by the present invention can be applied at the base station side.

Fig. 2 is an optional flow chart of a method for resource allocation of minimum-maximum decoding error rate in V2V multicast communication provided by an embodiment of the present invention. As shown in Fig. 2, the method includes the following steps:

S101. Obtain the system parameters of the Internet of Vehicles system, the first channel environment parameters corresponding to each terminal in the target V2V multicast group in the Internet of Vehicles system, and the V2I users in the Internet of Vehicles system that use the same communication resources as the target V2V multicast group The second channel environment parameter and the first transmission parameter currently corresponding to the terminal; the target V2V multicast group includes one transmitting terminal and multiple receiving terminals.

Here, the target V2V multicast group may be any V2V multicast group in the Internet of Vehicles system. Exemplarily, it may be the V2V multicast group shown in FIG. 1, and as shown in FIG. 1, the V2I client b and the target V2V multicast group use the same communication resource, thereby causing communication to the receiving end in the V2V multicast group interference.

Here, the system parameters of the Internet of Vehicles system may include: the size D of the security information data packet transmitted between the preset V2V multicast groups, the lower limit value of the transmission code length M _min , the upper limit value of the transmission code length M _max (allowing data transmission The maximum number of symbols), the preset maximum decoding error rate ε _max , the preset transmit power P _n,max of the transmitter, the preset maximum signal-to-dry ratio γ _max , the preset total system energy consumption E _tot , and the noise power σ ² .

Here, the base station may acquire the first channel environment parameter from the transmitting end in the target V2V multicast group, and acquire the second channel environment parameter from the V2I user end in the system. The first channel environment parameter corresponding to each terminal in the target V2V multicast group is the channel gain h _n,i from the receiving terminal to each transmitting terminal in the V2V multicast group, i=1,2,...,A, A is the target The total number of receiving terminals in the V2V multicast group, and the second channel environment parameter corresponding to the V2I user terminal is the channel gain h _b,i from the V2I user terminal to each transmitting terminal.

S102. According to the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the system parameter, the preset transmission parameter and the preset convergence threshold, multiple sets of transmission parameters are obtained through an optimization method; each set of transmission parameters includes a candidate transmission code length and a candidate second transmission parameter.

Here, the optimization method may be a coordinate descent method.

Here, each set of transmission parameters consists of a transmission code length and a transmission power.

Here, the preset transmission parameter is the initial second transmission power P _n ⁰ .

In some embodiments, the system parameters include a first parameter and a second parameter. Based on this, S102 may be implemented through the following steps:

S1021. According to the first parameter, determine the first constraint condition of the first preset optimization function and the second constraint condition of the second preset optimization function; the preset optimization function is used to represent the decoding error rate, signal-to-noise ratio, transmission code Long and the relationship between the second launch parameter.

Specifically, the first parameters are B, γ _max , P _n,max , M _min , M _max , ε _max and E _tot .

Specifically, the first preset optimization function is:

Specifically, the first constraint condition is:

为正整数，m为传输码长。Among them, ε _n,i is the decoding error rate of the i-th receiving end, γ _n,i (P _n ) is the signal-to-interference ratio of the i-th receiving end, V _n,i (P _n ) is the channel of the i-th receiving end Dispersion, Q(.) is a Gaussian function, P _n is the second emission parameter,

is a positive integer, and m is the transmission code length.

Specifically, the second preset optimization function is:

Specifically, the second constraint condition is:

其中，P_b为V2I用户端b的发射功率，V2V发射端n至接收端i在有限码长下的编码速率(bits/s/Hz)可以表示为：/>

(Q^-1为高斯函数Q的逆函数，/>

当V2V间传输的安全信息数据包大小固定为Dbits时，传输期间以码长m传输，那么编码率为R_n＝D/mbit/s/Hz，V2V接收端i的译码错误率表示为：ε_n,i(m,P_n)＝Q(f_n,i(m,P_n))，/>

因而，据此可以构建最小-最大译码错误率最优化问题：Here, the above-mentioned first preset optimization function and second preset optimization function are converted and obtained according to the constructed minimum-maximum decoding error rate optimization problem. The receiving signal-to-dry ratio of V2V receiver i can be expressed as:

Among them, P _b is the transmission power of V2I user terminal b, and the coding rate (bits/s/Hz) from V2V transmitting terminal n to receiving terminal i under the limited code length can be expressed as: />

(Q ^-1 is the inverse function of the Gaussian function Q, />

When the size of the security information data packet transmitted between V2V is fixed at Dbits, and the transmission period is transmitted with code length m, then the encoding rate is R _n =D/mbit/s/Hz, and the decoding error rate of V2V receiver i is expressed as: ε _n,i (m,P _n )=Q(f _n,i (m,P _n )),/>

Therefore, the minimum-maximum decoding error rate optimization problem can be constructed accordingly:

内。该最小-最大译码错误率最优化问题中，待优化的参数为m和P_n。通过固定第二发射功率P_n，连续码长优化子问题转为：/>

通过引入辅助变量u，可以将该问题转化为凸优化问题，即得到上述第一预设优化函数。通过固定传输码长m，第二发射功率分配子问题转化为：/>

通过引入辅助变量v，可以将该问题转化为凸优化问题，即得到上述第二预设优化函数。Among them, constraint condition C1 indicates that the achievable range of the transmission code length m is [M _min , M _max ], C2 ensures that the transmission code length is an integer, C3 indicates that the transmission power of the V2V transmitter cannot exceed the maximum transmission power P _n,max , and C4 guarantees that The reliability of V2V communication, that is, to limit the maximum tolerance of the decoding error rate of each receiving end to ε _max , C5 represents the minimum signal-to-interference-noise ratio constraint for all transmissions of V2V multicast, and C6 represents the total energy consumption of the system at

Inside. In the minimum-maximum decoding error rate optimization problem, the parameters to be optimized are m and P _n . By fixing the second transmission power P _n , the continuous code length optimization sub-problem is transformed into: />

By introducing the auxiliary variable u, the problem can be transformed into a convex optimization problem, that is, the above-mentioned first preset optimization function can be obtained. By fixing the transmission code length m, the second transmission power allocation sub-problem is transformed into: />

By introducing an auxiliary variable v, this problem can be transformed into a convex optimization problem, that is, the above-mentioned second preset optimization function can be obtained.

S1022. Using the preset transmission parameter as the initial second transmission parameter, according to the initial second transmission parameter, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the preset convergence threshold, the first preset The optimization function, the first constraint condition, the second preset optimization function and the second constraint condition are set, and the transmission code length and the second transmission parameter are iterated multiple times through the coordinate descent method to obtain the intermediate transmission code length.

Specifically, the second parameter is the power noise σ ² and the size D of the security information data packet.

Specifically, S1022 can be implemented through the following steps:

S1. In the t-th iteration, obtain the second transmission parameter obtained in the t-1th iteration, and combine the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter and the t-1th iteration Substituting the second transmission parameter obtained by iteration into the first preset optimization function, and solving the first preset optimization function according to the first constraint condition, to obtain the transmission code length of the t-th iteration; t is an integer greater than or equal to 1, When t is 1, the second transmission parameter obtained in the t-1th iteration is the initial second transmission parameter.

Here, solving tools such as MATLAB can be used to solve the problem.

S2. Substituting the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, and the transmission code length obtained by the t-th iteration into the second preset optimization function, and performing the first optimization function according to the second constraint condition The second preset optimization function is solved to obtain the second transmission parameter of the t-th iteration.

S3. According to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second transmission parameter and the transmission code length obtained in the t-1th iteration, and the second transmission code length obtained in the tth iteration The transmission parameters and the transmission code length respectively determine the decoding error rate of the t-1th time and the decoding error rate of the tth time of each receiving end.

Specifically, σ ² , D, P _b , h _n,i , h _m,i , P _n obtained from the t-1th iteration, and m obtained from the t-1th iteration can be substituted into the calculation of ε _n,i In the formula, the t-1 decoding error rate of each receiver i is calculated; and, σ ² , D, P _b , h _n,i , h _m,i , the t-1 iteration are Substitute P _n from the t-1th iteration into the calculation formula of εn _,i to calculate the t-th decoding error rate of each receiver i.

S4. According to the maximum decoding error rate among the decoding error rates of the t-1th time and the maximum decoding error rate among the decoding error rates of the tth time, calculate the objective function value of the tth time.

Specifically, the maximum decoding error rate ε ^{t-1 in the decoding error rate of the t-} 1th time and the maximum decoding error rate ε ^t in the decoding error rate of the t-th time can be made to obtain the difference ; The ratio between the absolute value of the obtained difference |ε ^t-1 -ε ^t | and the maximum decoding error rate ε ^t-1 in the decoding error rate of the t-1th time is used as the ratio of the t-th time Objective function value |ε ^t-1 -ε ^t |/ε ^t-1 .

S5. When the objective function value of the t-th iteration is less than or equal to the preset convergence threshold, the iteration ends, and the transmission code length of the t-th iteration is used as an intermediate transmission code length.

For example, when |ε ^t-1 -ε ^t |/ε ^t-1 ≤ Δ, the iteration ends, and the transmission code length of the t-th iteration is used as the intermediate transmission code length m*.

S1023. Obtain multiple sets of transmission parameters according to the intermediate transmission code length, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second preset optimization function, and the second constraint condition.

Specifically, the intermediate transmission code length m* can be rounded down to obtain an integer; the integer and adjacent integers of the integer can be used as candidate transmission code lengths; each candidate transmission code length, the second parameter, the first A channel environment parameter, a second channel environment parameter and a first transmission parameter are substituted into the second preset optimization function, and the second preset optimization function is solved according to the second constraint condition to obtain a candidate first code length corresponding to each candidate transmission code length Two transmission parameters: using each candidate transmission code length and a corresponding candidate second transmission parameter as a set of transmission parameters to obtain multiple sets of transmission parameters.

从而可以将m1、σ²、D、P_b、h_n,i、h_m,i代入上述第二预设优化函数，并通过对第二预设优化函数求解，得到一个对应的候选第二发射功率P1_n，以及将m2、σ²、D、P_b、h_n,i、h_m,i代入上述第二预设优化函数，并通过对第二预设优化函数求解，得到一个对应的候选第二发射功率P2_n，则(m1；P1_n)和(m2；P2_n)为得到的两组传输参数。For example, the candidate transmission code length can be:

Therefore, m1, σ ² , D, P _b , h _n,i , and h _m,i can be substituted into the above-mentioned second preset optimization function, and by solving the second preset optimization function, a corresponding candidate second launch Power P1 _n , and substituting m2, σ ² , D, P _b , h _n,i , h _m,i into the above-mentioned second preset optimization function, and solving the second preset optimization function to obtain a corresponding candidate For the second transmit power P2 _n , then (m1; P1 _n ) and (m2; P2 _n ) are the obtained two sets of transmission parameters.

S103. Select a set of transmission parameters from multiple sets of transmission parameters as the optimal transmission parameters of the transmitting end when the transmitting end communicates with multiple receiving ends; wherein, under the optimal transmission parameters, the decoding error rate of each receiving end is The maximum decoding error rate is the smallest.

Specifically, the maximum decoding error rate among the decoding error rates of each receiving terminal under each set of transmission parameters can be determined, and multiple maximum decoding error rates corresponding to multiple sets of transmission parameters can be obtained; A set of transmission parameters corresponding to the minimum value in the error rate is used as the optimal transmission parameter.

The present invention minimizes the maximum decoding error rate of the V2V multicast group by optimizing the transmission power and communication code length, and controls the total energy consumption and coding rate of the system. It improves the reliability and effectiveness of multicast, and improves traffic safety.

The technical effect that the present invention can achieve will be further described below in combination with simulation experiments.

The comparison methods are quasi-convex path-following algorithm (Path-Following Algorithm, PFA) and equal power allocation (Equal power allocation, EPA). Among them, the PFA comparison method approximately converts the non-convex problem into a quasi-convex problem, and jointly allocates the code length and power based on the path tracking algorithm; EPA takes the power as the maximum threshold based on this method, and only optimizes the code length.

P_n,max＝23dBm，M_max＝200时，本方法(MDEP)和对比方法(PFA、EPA)的数据包信息量、接收端个数对译码错误率的影响关系图。从图3中可以看出，随着数据包信息量的提升，译码错误率也随之增大。这意味着，越长的数据信息量编入同一码长的块中，在传输时越容易产生错误。本方法(MDEP)在接收端数量为I＝5与I＝10时，皆比其他两种方法的译码错误率低。因为本方法(MDEP)对码长与发射功率进行联合最优化，而EPA只针对码长进行优化，PFA将问题近似为拟凹，无法确保求解的最优性。当接收端数量增多时，各方法译码错误率均增大，更多的接收端意味着更大的传输范围，路径损耗增加导致传输质量下降。Figure 3 shows the

When P _n,max ＝23dBm, M _max ＝200, this method (MDEP) and the comparison method (PFA, EPA) the data packet information amount, the number of receivers on the decoding error rate. It can be seen from Figure 3 that as the amount of information in the data packet increases, the decoding error rate also increases. This means that the longer the amount of data information is encoded into a block with the same code length, the easier it is to generate errors during transmission. This method (MDEP) has a lower decoding error rate than the other two methods when the number of receiving ends is I=5 and I=10. Because this method (MDEP) jointly optimizes the code length and transmit power, while EPA only optimizes the code length, and PFA approximates the problem as quasi-concave, which cannot ensure the optimality of the solution. When the number of receivers increases, the decoding error rate of each method increases, more receivers mean a larger transmission range, and the increase in path loss leads to a decrease in transmission quality.

Fig. 4 shows the relationship diagram of the influence of the vehicle speed and the number of receivers on the decoding error rate in this method (MDEP) and the comparison method (PFA) when P _n,max =23dBm, M _max =200, D=200 bits. It can be seen from Figure 4 that as the vehicle speed increases, the decoding error rate increases. This means that the average spacing of the expressway model described in 3GPP TR 36.885 is 2.5×v _s /3.6m, the greater the vehicle speed, the greater the maximum transmission distance between V2V groups, and the extremely large path loss will cause a sharp drop in system performance. However, this method converges to an error rate constraint threshold of 0.001, which can meet the requirements of low-latency and high-reliability communication, and the comparison method PFA converges to an upper limit of 0.5. This method is better than the comparison method at the receiving end I=5 and I=10.

The present invention compares the performance with the comparison method, and analyzes the influence of the amount of data packet information, vehicle speed, and the number of receiving terminals on the V2V multicast decoding error rate, and verifies the superiority of the method, which can achieve more than 99.9% of low delay and high reliability. The reliability rate improves the reliability and security of V2V multicast transmission.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (9)

1. A V2V multicast communication min-max decoding error rate resource allocation method, comprising:

respectively acquiring system parameters of an internet of vehicle system, first channel environment parameters corresponding to the front of each end in a target V2V multicast group in the internet of vehicle system, and second channel environment parameters and first transmission parameters corresponding to the current V2I user ends which use the same communication resources in the internet of vehicle system and the target V2V multicast group; the target V2V multicast group comprises a transmitting end and a plurality of receiving ends;

obtaining a plurality of groups of transmission parameters through an optimization method according to the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the system parameter, a preset transmission parameter and a preset convergence threshold; each set of transmission parameters includes a candidate transmission code length and a candidate second transmission parameter;

selecting a group of transmission parameters from the multiple groups of transmission parameters as optimal transmission parameters of the transmitting end when the transmitting end and the multiple receiving ends currently communicate; and under the optimal transmission parameters, the maximum decoding error rate in the decoding error rates of all the receiving ends is minimum.

2. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 1, wherein said selecting a set of transmission parameters from said plurality of sets of transmission parameters as optimal transmission parameters for said transmitting end when said transmitting end is currently communicating with said plurality of receiving ends comprises:

determining the maximum decoding error rate in the decoding error rates of all receiving ends under each group of transmission parameters to obtain a plurality of maximum decoding error rates corresponding to the groups of transmission parameters one by one;

and taking a group of transmission parameters corresponding to the minimum value in the maximum coding error rates as the optimal transmission parameters.

3. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 1, wherein said system parameters comprise a first parameter and a second parameter; the optimization method comprises a coordinate descent method; the obtaining a plurality of groups of transmission parameters through an optimization method according to the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the system parameter, a preset transmission parameter and a preset convergence threshold comprises the following steps:

determining a first constraint condition of a first preset optimization function and a second constraint condition of a second preset optimization function according to the first parameter; the preset optimization function is used for expressing the relation among the decoding error rate, the signal to noise ratio, the transmission code length and the second transmission parameter;

taking the preset emission parameter as an initial second emission parameter, and carrying out multiple iterations of a transmission code length and a second emission parameter according to the initial second emission parameter, the second parameter, the first channel environment parameter, the second channel environment parameter, the first emission parameter, the preset convergence threshold, the first preset optimization function, the first constraint condition, the second preset optimization function and the second constraint condition by using the coordinate descent method to obtain an intermediate transmission code length;

and obtaining the multiple groups of transmission parameters according to the intermediate transmission code length, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second preset optimization function and the second constraint condition.

4. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 3, wherein said obtaining an intermediate transmission code length according to the initial second transmission parameter, the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the preset convergence threshold, the first preset optimization function, the first constraint, the second preset optimization function, and the second constraint by performing a plurality of iterations of the transmission code length and the second transmission parameter by the coordinate descent method comprises:

during the t-th iteration, obtaining a second emission parameter obtained by the t-1 th iteration, substituting the second parameter, the first channel environment parameter, the second channel environment parameter, the first emission parameter and the second emission parameter obtained by the t-1 th iteration into the first preset optimization function, and solving the first preset optimization function according to the first constraint condition to obtain the transmission code length of the t-th iteration; t is an integer greater than or equal to 1, and when t is 1, the second emission parameter obtained by the t-1 th iteration is the initial second emission parameter;

substituting the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter and the transmission code length obtained by the t-th iteration into the second preset optimization function, and solving the second preset optimization function according to the second constraint condition to obtain a second transmission parameter of the t-th iteration;

respectively determining the decoding error rate of the t-1 th time and the decoding error rate of the t time of each receiving end according to the second parameter, the first channel environment parameter, the second transmission parameter and the transmission code length obtained by the t-1 th iteration, and the second transmission parameter and the transmission code length obtained by the t-1 th iteration;

calculating an objective function value of the t time according to the maximum decoding error rate in the t-1 th decoding error rate and the maximum decoding error rate in the t time decoding error rate;

and ending iteration when the objective function value of the t time is smaller than or equal to the preset convergence threshold value, and taking the transmission code length of the t time iteration as the intermediate transmission code length.

5. The method for allocating resources of a minimum-maximum decoding error rate for V2V multicast communication according to claim 4, wherein determining the decoding error rate of the t-1 st time and the decoding error rate of the t time according to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second transmission parameter and the transmission code length obtained by the t-1 st time iteration, and the second transmission parameter and the transmission code length obtained by the t-1 st time iteration, respectively, comprises:

according to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second transmission parameter obtained by the t-1 iteration and the transmission code length, calculating and determining the t-1 decoding error rate of each receiving end;

and calculating the coding error rate of the t time of each receiving end according to the second parameter, the first channel environment parameter, the second channel environment parameter, the first transmission parameter, the second transmission parameter obtained by the t time of iteration and the transmission code length.

6. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 4, wherein said calculating the objective function value of the t-th time based on the maximum decoding error rate among the decoding error rates of the t-1 th time and the maximum decoding error rate among the decoding error rates of the t-th time comprises:

the maximum decoding error rate in the decoding error rate of the t-1 th time is differenced with the maximum decoding error rate in the decoding error rate of the t time, and a difference value is obtained;

and taking the ratio of the absolute value of the obtained difference value to the maximum decoding error rate in the t-1 th decoding error rate as the objective function value of the t.

7. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 3, wherein said obtaining said plurality of sets of transmission parameters according to said intermediate transmission code length, said second parameter, said first channel environment parameter, said second channel environment parameter, said first transmission parameter, said second preset optimization function, and said second constraint comprises:

rounding down the intermediate transmission code length to obtain an integer;

taking the integer and the adjacent integer of the integer as candidate transmission code lengths;

substituting each candidate transmission code length, the second parameter, the first channel environment parameter, the second channel environment parameter and the first transmission parameter into the second preset optimization function, and solving the second preset optimization function according to the second constraint condition to obtain one candidate second transmission parameter corresponding to each candidate transmission code length;

and taking each candidate transmission code length and a corresponding one of the candidate second transmission parameters as a group of transmission parameters to obtain the multiple groups of transmission parameters.

8. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 3, wherein said first preset optimization function is:

the first constraint condition is:

wherein ε _n,i For the decoding error rate of the i-th receiving end, i=1, 2.A, A is the total number of receiving ends in the target V2V multicast group, gamma _n,i (P _n ) For the signal-to-dry ratio of the ith receiving end, V _n,i (P _n ) For the channel dispersion at the ith receiver, Q (-) is a Gaussian function, P _n Is a second emission parameter,

Is a positive integer, M is a transmission code length, D is a preset safety information data packet size, M _min For transmitting the lower limit value of the code length, M _max For transmitting the upper limit value of the code length epsilon _max The maximum decoding error rate is preset.

9. The V2V multicast communication min-max decoding error rate resource allocation method according to claim 8, wherein the second preset optimization function is:

the second constraint condition is:

wherein P is _n,max For presetting the maximum second emission parameter, gamma _max Is a preset maximum signal-to-dry ratio E _tot The total energy consumption of the system is preset.

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