CN112615647A - Broadband power line carrier communication cross-layer resource allocation method for power internet of things concurrent mixed service - Google Patents

Abstract

The invention discloses a broadband power line carrier communication cross-layer resource allocation method for a power internet of things concurrent mixed service, which comprises the following steps of: s1, initializing data; s2, selecting the ith moment, reading the queue length of the user k in the buffer area, and acquiring the instantaneous rate of the user k; s3, judging the category of the user k, and calculating a utility function value of the user: s4, sequencing the utility function values of the users in a descending order to obtain a scheduling sequence based on the utility function values and transmitting the scheduling sequence to a physical layer, and distributing physical layer resources by the users; and S5, after the resource allocation is finished, updating the length and the rate of the queue of the buffer area, and finishing the resource scheduling of the user. And the service is dynamically prioritized according to the service QoS requirement and the current network state, so that the data packet waiting time delay and the packet loss can be effectively reduced, and the QoS requirements of more users can be met.

Description

A cross-layer resource allocation method for broadband power line carrier communication for concurrent hybrid services of power Internet of things

technical field

The invention belongs to the field of communication technologies, and in particular relates to a cross-layer resource allocation method for broadband power line carrier communication for concurrent mixed services of the Internet of Things.

Background technique

Power Line Communication (PLC) is a special communication method that uses high-frequency modulated signals and uses power lines as a medium for data transmission. According to the voltage level, power line carrier communication can be divided into three types: high voltage carrier (over 35Kv), medium voltage carrier (10Kv) and low voltage carrier (380V/220V). Power line carrier communication naturally has the characteristics of electrical equipment connection, flexible access of various terminal equipment, and low construction cost. It is one of the effective communication methods to solve the "last mile" information exchange problem. Power line carrier communication technology has gradually developed from traditional narrowband communication to broadband power line carrier communication. OFDM is Orthogonal Frequency Division Multiplexing technology, which is a kind of multi-carrier modulation. The parallel transmission of high-speed serial data is realized through frequency division multiplexing, which has a relatively high performance. Good anti-multipath weakening ability can support user access. Using OFDM technology, the communication rate is increased from several thousand bps to several megabits to tens of megabits per second, which greatly improves the communication performance.

The power line channel is an open and shared channel, and each phase has an independent PLC gateway. Each PLC device needs to compete for the resources of its own phase on the shared power channel. The essence of the multi-user dynamic resource allocation problem is that according to the state information of the power line channel, the Different sub-carriers are dynamically allocated for real-time (RT) users and non-real-time (NRT) users within each OFDM symbol in real time, and different modulation methods are adaptively selected on the corresponding sub-carriers according to the size of the channel gain, and loaded according to the Shannon formula. corresponding bits.

The power Internet of Things refers to a smart service system that provides networking services to terminals connected to the power grid and realizes the interconnection of all things and human-computer interaction in all aspects of the power system. In the construction of the power Internet of things, as the ready-made communication channel with the widest coverage in the power system, the use of the power line carrier communication technology can minimize the component cost of the intelligent communication network. With the access of a large number of intelligent sensing devices, the traditional broadband power line carrier communication resource allocation method does not consider the user QoS requirements of mixed services and the queue situation of the MAC layer buffer area, and cannot reasonably schedule users according to the mixed service traffic, resulting in different users. Poor distribution balance.

Therefore, in order to solve the above technical problems, it is necessary to design a cross-layer resource allocation method for broadband power line carrier communication capable of fast, accurate and reliable transmission, real-time control of resources, and avoidance of network congestion.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a cross-layer resource allocation method for broadband power line carrier communication for concurrent mixed services in the power Internet of Things, which considers user QoS requirements of mixed services, reasonably schedules resources, and has high user allocation balance.

The technical scheme of the present invention is as follows:

A cross-layer resource allocation method for broadband power line carrier communication for concurrent hybrid services of the power Internet of Things, comprising the following steps:

S1. Initialize data, set time i, user k, user instantaneous rate υ _k (0)=0, queue length Q _k (0)=0 of user k in the buffer, RT user set SRT={1,2 ,.....,h}, NRT user set SNRT={1,2,.....,l}, buffer data packet waiting delay D _k (i);

S2. Select the ith moment, read the queue length Q _k (i) of user k in the cache, and obtain the instantaneous rate ν _k (i) of user k;

S3. Determine the category of user k:

通过如下公式计算：S301. If user k is an RT user, obtain the maximum allowable delay T _k , calculate the buffer data packet waiting delay D _k ( _i ) and the The utility function value of the user's next moment i+1

Calculated by the following formula:

为RT用户k在第i个时刻为避免缓冲区内数据分组等待超时的最低速率，A_k(i)为第i个时刻到达缓存区的数据分组数；Among them, Q _k (i) is the queue length of user k in the buffer area at the ith moment, υ _k (i) is the instantaneous rate of user k, L is the number of bits contained in each data packet,

is the lowest rate of RT user k at the ith moment in order to avoid data packets in the buffer to wait for timeout, A _k (i) is the number of data packets arriving in the buffer zone at the ith moment;

计算出当前时刻i的分组损耗

和该用户下一时刻i+1的效用函数值

通过如下公式计算：S302. If user k is an NRT user, obtain the maximum allowable packet loss

Calculate the packet loss at the current time i

and the utility function value of the user at the next moment i+1

Calculated by the following formula:

为NRT用户k在第i个时刻为避免缓冲区内数据分组等待超时的最低速率，r为用户k的数据分组在满足分组损耗要求下的最小保障速率，L为每个数据分组包含的比特数，B为缓存区内最大允许长度，

为用户k的最大允许分组损耗，

为分组丢失率，

为差错率；in,

is the minimum rate for NRT user k at the i-th moment to avoid the data packet waiting time-out in the buffer, r is the minimum guaranteed rate of the data packet of user k under the requirement of packet loss, and L is the number of bits contained in each data packet , B is the maximum allowable length in the buffer,

is the maximum allowable packet loss for user k,

is the packet loss rate,

is the error rate;

l个NRT用户的效用函数值

设定RT用户调度序列高于NRT用户，根据效用函数值的大小对用户降序排序，得到基于效用函数值的调度序列，并将第i时刻的调度序列传递给物理层，物理层根据该调度序列为用户分配物理层资源；S4. Calculate the utility function value of h RT users

Utility function value for l NRT users

Set the scheduling sequence of RT users to be higher than that of NRT users, sort the users in descending order according to the value of the utility function, obtain the scheduling sequence based on the value of the utility function, and pass the scheduling sequence at the i-th time to the physical layer. Allocate physical layer resources to users;

S5. After the physical layer resource allocation in step S4 is completed, update the rate υ _k* (i) actually obtained by user k ^* and the queue length Q _k* (i) in the buffer, and end the resource scheduling of this user. .

In the above technical solution, after the resource scheduling in the step S5, let i=i+1 time, return to the step S2, and continue to perform resource allocation for the user.

In the above technical solution, the smart terminal data collected in the step S2 includes power consumption data, load curve data, and low-voltage collection data.

和差错率

In the above technical solution, in the step S301, the arrival process of the data packet is set to obey the Poisson distribution, and the buffer data packet waiting delay is defined according to the principle of first-in, first-out. Due to the limitation of the maximum queue length in the buffer , the data packets exceeding the maximum queue length B will be discarded, resulting in the loss of data packets, and due to the interference of each symbol signal during the power line carrier communication process, resulting in bit errors, the size of the packet loss depends on the packet loss rate

and error rate

The advantages and positive effects that the present invention has are:

1. The provisioning method of the present invention dynamically prioritizes services according to service QoS requirements and current network status, which can effectively reduce data packet latency and packet loss, and meet the QoS requirements of more users.

2. Compared with the traditional polling or static preset methods, the deployment method of the present invention can be adaptively adjusted according to the service QoS requirements and the waiting grouping situation of the buffer area, so as to be better suitable for the concurrent mixing of the power Internet of things. Business scene.

Description of drawings

Fig. 1 is the flow chart of the resource allocation method of the present invention;

Fig. 2 is the schematic diagram of packet waiting delay-time of RT ₁ user in Embodiment 1;

Fig. 3 is the grouping waiting delay-time schematic diagram of RT ₂ users in embodiment 1;

Fig. 4 is the packet loss-time schematic diagram of NRT ₁ user in embodiment 1;

FIG. 5 is a schematic diagram of packet loss-time for NRT ₂ users in Embodiment 1. FIG.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, not to limit the present invention, and in no way limit the protection scope of the present invention.

Example 1

As shown in the figure, a broadband power line carrier communication cross-layer resource allocation method for concurrent hybrid services of the Internet of Things of the present invention includes the following steps:

S1. Initialize data, set time i, user k, user instantaneous rate υ _k (0)=0, queue length Q _k (0)=0 of user k in the buffer zone, RT user set S _RT ={1, 2,.....,h}, NRT user set S _NRT ={1,2,.....,l}, buffer data packet waiting delay D _k (i);

S2. Select the ith moment, read the queue length Q _k (i) of user k in the cache, and obtain the instantaneous rate ν _k (i) of user k;

S3. Determine the category of user k:

通过如下公式计算：S301. If user k is an RT user, obtain the maximum allowable delay T _k , calculate the buffer data packet waiting delay D _k ( _i ) and the The utility function value of the user's next moment i+1

Calculated by the following formula:

为RT用户k在第i个时刻为避免缓冲区内数据分组等待超时的最低速率，A_k(i)为第i个时刻到达缓存区的数据分组数；Among them, Q _k (i) is the queue length of user k in the buffer area at the ith moment, υ _k (i) is the instantaneous rate of user k, L is the number of bits contained in each data packet,

is the lowest rate of RT user k at the ith moment in order to avoid data packets in the buffer to wait for timeout, A _k (i) is the number of data packets arriving in the buffer zone at the ith moment;

计算出当前时刻i的分组损耗

和该用户下一时刻i+1的效用函数值

通过如下公式计算：S302. If user k is an NRT user, obtain the maximum allowable packet loss

Calculate the packet loss at the current time i

and the utility function value of the user at the next moment i+1

Calculated by the following formula:

为NRT用户k在第i个时刻为避免缓冲区内数据分组等待超时的最低速率，r为用户k的数据分组在满足分组损耗要求下的最小保障速率，L为每个数据分组包含的比特数，B为缓存区内最大允许长度，

为用户k的最大允许分组损耗，

为分组丢失率，

为差错率；in,

is the minimum rate for NRT user k at the i-th moment to avoid the data packet waiting time-out in the buffer, r is the minimum guaranteed rate of the data packet of user k under the requirement of packet loss, and L is the number of bits contained in each data packet , B is the maximum allowable length in the buffer,

is the maximum allowable packet loss for user k,

is the packet loss rate,

is the error rate;

l个NRT用户的效用函数值

设定RT用户调度序列高于NRT用户，根据效用函数值的大小对用户降序排序，得到基于效用函数值的调度序列，并将第i时刻的调度序列传递给物理层，物理层根据该调度序列为用户分配物理层资源；S4. Calculate the utility function value of h RT users

Utility function value for l NRT users

Set the scheduling sequence of RT users to be higher than that of NRT users, sort the users in descending order according to the value of the utility function, obtain the scheduling sequence based on the value of the utility function, and pass the scheduling sequence at the i-th time to the physical layer. Allocate physical layer resources to users;

S5. After the physical layer resource allocation in step S4 is completed, update the rate υ _k* (i) actually obtained by user k ^* and the queue length Q _k* (i) in the buffer, and end the resource scheduling of this user. .

More specifically, after the resource scheduling in the step S5, let i=i+1 time, return to the step S2, and continue to perform resource allocation for the user.

Further, the smart terminal data collected in the step S2 includes power consumption data, load curve data, and low-voltage collection data.

和差错率

Further, in the step S301, the arrival process of the data packets is set to obey the Poisson distribution, and the buffer data packet waiting delay is defined according to the principle of first-in, first-out. Due to the limitation of the maximum queue length in the buffer, exceeding the Data packets with the maximum queue length B will be discarded, resulting in data packet loss, and due to the interference of each symbol signal during the power line carrier communication process, resulting in bit errors, the size of the packet loss depends on the packet loss rate.

and error rate

In order to verify the effectiveness of the allocating method of the present invention, take the user who accesses the broadband power line carrier communication system as an example to analyze on the Matlab simulation platform, and the system setting parameters are as shown in Table 1:

Table 1

The experiment includes 2 RT users and 2 NRT users using PLC cascade connection to communicate with the gateway. The channel quality from high to low is RT ₁ >RT ₂ , NRT ₁ >NRT ₂ , in extreme cases when the system resources are insufficient , and compare the RT user data packet latency and NRT user data packet loss with the method of the present invention, the maximum throughput algorithm and the Gong algorithm, respectively.

It can be seen from Fig. 2-Fig. 5 that the maximum throughput algorithm schedules RT ₁ and NRT ₁ users in consecutive times, resulting in RT ₂ and NRT ₂ user data packets not being processed in time, and RT ₂ user packets waiting when The delay is as high as 12.46ms exceeding the maximum allowable delay of 10ms, while the NRT ₂ user packet loss is as high as 3.29% exceeding the threshold of 1.00%.

Although Gong's algorithm satisfies the delay requirements of RT users, because the algorithm uses the principle of maximum cumulative fairness deviation to schedule users for NRT users, all NRT users exceed the threshold, which are 2.89% and 2.67%, respectively.

The allocation method of the present invention can meet the delay requirements of RT ₁ and RT ₂ users when the system resources are insufficient in extreme cases, while NRT users only exceed the packet loss threshold at certain intermittent moments, wherein the packet losses of NRT ₁ and NRT ₂ are respectively The average packet loss does not exceed the threshold of 1.00%. Taking NRT ₂ users as an example, the proposed algorithm is 72.04% and 65.54% lower than the maximum throughput algorithm and Gong algorithm, respectively.

The present invention has been exemplarily described above. It should be noted that, without departing from the core of the present invention, any simple deformation, modification, or other equivalent replacements that can be performed by those skilled in the art without any creative effort fall into the scope of the present invention. the scope of protection of the invention.

Claims (4)

1. a broadband power line carrier communication cross-layer resource allocation method for the concurrent mixed business of the power Internet of things, is characterized in that, comprises the following steps: S1. Initialize data, set time i, user k, user instantaneous rate υ _k (0)=0, queue length Q _k (0)=0 of user k in the buffer zone, RT user set S _RT ={1, 2,.....,h}, NRT user set S _NRT ={1,2,.....,l}, buffer data packet waiting delay D _k (i); S2. Select the ith moment, read the queue length Q _k (i) of user k in the cache, and obtain the instantaneous rate ν _k (i) of user k; S3. Determine the category of user k: S301. If user k is an RT user, obtain the maximum allowable delay T _k , calculate the buffer data packet waiting delay D _k ( _i ) and the The utility function value of the user's next moment i+1

Calculated by the following formula:

Among them, Q _k (i) is the queue length of user k in the buffer area at the ith moment, υ _k (i) is the instantaneous rate of user k, L is the number of bits contained in each data packet,

is the lowest rate of RT user k at the ith moment in order to avoid data packets in the buffer to wait for timeout, A _k (i) is the number of data packets arriving in the buffer zone at the ith moment; S302. If user k is an NRT user, obtain the maximum allowable packet loss

Calculate the packet loss at the current time i

and the utility function value of the user at the next moment i+1

Calculated by the following formula:

in,

is the minimum rate for NRT user k at the i-th moment to avoid the data packet waiting time-out in the buffer, r is the minimum guaranteed rate of the data packet of user k under the requirement of packet loss, and L is the number of bits contained in each data packet , B is the maximum allowable length in the buffer,

is the maximum allowable packet loss for user k,

is the packet loss rate,

is the error rate; S4. Calculate the utility function value of h RT users

Utility function value for l NRT users

Set the scheduling sequence of RT users to be higher than that of NRT users, sort the users in descending order according to the value of the utility function, obtain the scheduling sequence based on the value of the utility function, and pass the scheduling sequence at the i-th time to the physical layer. Allocate physical layer resources to users; S5. After the physical layer resource allocation in step S4 is completed, update the rate υ _k* (i) actually obtained by user k ^* and the queue length Q _k* (i) in the buffer, and end the resource scheduling of this user. . 2 . The method for allocating cross-layer resources for broadband power line carrier communication according to claim 1 , wherein: after the resource scheduling in step S5, set i=i+1 time, return to step S2, and continue as User allocates resources. 3 . The cross-layer resource allocation method for broadband power line carrier communication according to claim 1 , wherein the intelligent terminal data collected in the step S2 includes power consumption data, load curve data, and low-voltage collection data. 4 . 4 . The method for allocating cross-layer resources for broadband power line carrier communication according to claim 1 , wherein in the step S301 , the arrival process of data packets is set to obey Poisson distribution and follow the principle of first-in, first-out. 5 .

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