Economical design method of linear polymorphic continuous connection system considering cost and signal loss

Abstract

The invention provides an economic design method of a linear multi-state continuous connection system (LMCCS) considering cost and signal loss. The method is used for evaluating an expected signal score which can be received by an aggregation node influenced by signal loss in the LMCCS, and mainly comprises the following steps of: constructing an expected signal score receiving model of a node and a subsystem at each position in the LMCCS by utilizing a universal generation function (UGF) method; joint optimization is carried out on node construction and CEs allocation strategies; balancing three different performance indexes (including system cost, reliability and expected receivable signal fraction) of the LMCCS to reduce the system cost to the maximum extent; the provided model method is explained by using three specific examples. According to the method, a large amount of work is carried out aiming at the signal loss problem which is still not solved in the transmission process at present, and an optimal design strategy for reducing the system cost by determining CEs allocation and node construction is put forward under the condition that constraint conditions of certain system reliability and expected received signal fraction are fully considered.

Description

Technical Field

[0001] The present invention belongs to the technical field of automatic control of power systems, and particularly relates to an automatic demand response method for electric vehicle charging based on real-time electricity prices. Background Art

[0002] Linear multi-state continuous connection systems (LMCCS) are widely used in the field of communication. The system consists of multiple linearly ordered nodes, where the first node is the starting node and the last node is the convergence node. Connecting elements (CEs) are assigned to nodes other than the convergence node to play a role in connecting to subsequent nodes. If the starting node is disconnected from the convergence node, it will cause system failure. In the field of communication, signal loss is a common problem in the signal transmission process, seriously affecting the reliability of the communication system. However, existing work lacks research on signal loss, that is, there may be a certain loss when the signal reaches the destination node. Therefore, how to reduce signal loss while reducing system cost on the premise of ensuring the normal operation of LMCCS is a technical problem that researchers urgently need to solve. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an economic design method for LMCCS considering cost and signal loss, and fully consider the problem of determining the optimal design strategy for minimizing system cost by determining CEs allocation and node construction under the constraints of meeting certain system reliability and expected received signal fraction.

[0004] An economic design method for LMCCS considering cost and signal loss, characterized in that the method specifically includes the following steps:

[0005] Step 1: Collect data such as the cost and performance data of different types of CEs (i.e., the signal fraction of different CEs transmitted to different distances), node construction costs, etc.

[0006] Step 2: Select the use of the universal generating function (UGF) method to construct the expected signal fraction reception model of nodes and subsystems in LMCCS, and measure the expected signal fraction received by CEs from different distances under different working states.

[0007] Step 3: Establish the expected signal fraction reception models of full nodes and LMCCS considering node construction respectively, and measure the expected signal fraction received by CEs from different distances under different working states.

[0008] Step 4: According to the known expected signal reception model of LMCCS, measure the expected signal fraction finally received by the convergence node of the system, system reliability and cost. Description of the Drawings

[0009] Figure 1 This is the flowchart of the economic design method of the LMCCS that takes into account cost and signal loss provided by the present invention. Detailed implementation mode

[0010] The following will describe the preferred embodiments in detail with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its applications.

[0011] As Figure 1 shown, this is an economic design method of the LMCCS that takes into account cost and signal loss of the present invention, and the specific steps are as follows:

[0012] Step 1: Collect data such as the costs and performances of different types of CEs (i.e., the signal scores of different CEs transmitted to different distances), the node construction costs, etc.

[0013] Step 2: Use the UGF method to establish the expected signal score reception model for each node in the LMCCS, and measure the expected signal scores received from different distances by the CEs on each node under different working states.

[0014] The expected signal score reception model for each node is as follows:

[0015]

[0016] In the formula, is the UGF of the performance distribution of node C i ; C i is the node at position i; is the probability that node C i is in state k, where is the number of different states of node C i ; is the signal score transmitted by node C i when it is in state k, where z is an indicator variable without practical significance.

[0017] The information of the UGF at node C i is combined and expressed in a matrix as follows;

[0018]

[0019] In the formula, is the signal score transmitted from node C i in state k to the connection range l, where l = 1,..., N - i + 1 and

[0020] Step 3: Using the UGF method, establish the expected signal fraction reception model of the full-node LMCCS, and measure the expected signal fractions received by the CEs from different distances under different working states.

[0021] The convergence node C of the system in the present invention i+1 The received signal is divided into two parts: from C i and from S i-1 , where S i-1 represents the subsystem composed of the nodes built from the 1st position to the (i - 1)th position, where i = 2,..., N. N is the total number of positions of the built nodes in the LMCCS (excluding the convergence node). The expected signal fraction reception model of the subsystem is as follows:

[0022]

[0023] In the formula, is the UGF of the performance distribution of the subsystem S i-1 ; is the number of different states of the subsystem S i-1 ; is the probability that the subsystem S i-1 is in state k. is the signal fraction transmitted by the subsystem S i-1 in state k, where

[0024] In the present invention, the known node C and the UGF of the subsystem S i are combined using the synthesis operator i-1 to obtain the UGF of the full-node LMCCS. The expected signal fraction reception model of the full-node LMCCS is as follows:

[0025]

[0026] In the formula, is the UGF of the performance distribution of the system S i ; is the signal fraction transmitted by the subsystem S i-1 in state k to the connection range l, where l = 1,..., N - i + 1 and

[0027] Step 4: Using the UGF method, establish the expected signal fraction reception model of the LMCCS considering the node construction situation, and measure the expected signal fractions received by the CEs from different distances when the CEs are in different working states under this premise.

[0028] In the present invention, the synthesis operator is used to combine S i-1Combined with the empty position i without a constructed node to obtain S i . If the position i is empty, then S i 's signal score remains the same as S i-1 , but the position i should be excluded from the connection range of S i . Therefore, at this time, the expression regarding S i and S i-1 is:

[0029]

[0030] Through iteration, the expected signal score reception model of S i considering node construction is obtained as follows:

[0031]

[0032] In the formula, b i is a Boolean variable indicating whether a node is constructed at position i (b i = 1) or not (b i = 0), where i = 1,..., N + 1.

[0033] Step 5: Use the UGF method to establish the expected signal score reception model of LMCCS considering node construction, and measure the expected signal score finally received by the sink node of the system.

[0034] Using this iterative method, the expected signal score reception model of S N (i = N) of LMCCS considering node construction is obtained as follows:

[0035]

[0036] In the formula, is the UGF of the performance distribution of the system.

[0037] Since there is only one sink node left for S N to connect, that is, the receiver, therefore the expected signal score received by the receiver from the nodes constructed in LMCCS is as follows:

[0038]

[0039] In the formula, E is the expected receivable signal score of the sink node C N+1 .

[0040] Step 6: Use the known LMCCS expected signal reception model to measure the system reliability and cost.

[0041] The present invention sets the minimum requirement for the fraction of reliable and acceptable signals in the system as r, and the reliability of the system is as follows:

[0042]

[0043] where R is the reliability of the LMCC under consideration; δ is to judge whether the is in state k and meets the minimum requirement r. If is true, then 1(x k ≥ w) = 1; otherwise 1(x k ≥ w) = 0.

[0044] The costs involved in the present invention mainly consist of two parts: the cost of constructing nodes and the cost of deploying different types of CEs on the nodes. The cost calculation of LMCCS is as follows:

[0045]

[0046] where TC is the total cost of LMCCS; h i is the type of CE deployed on node C i ; is the cost required for the CE deployed on node C i ; V C is the cost of constructing a node.

[0047] Case Study

[0048] Taking radio relay transmission as an example, the signal is transmitted from the transmitter in the LMCCS to the receiver. A signal source is deployed at the first site C 1 in the system, and a receiver is deployed at the last site C N+1 . For the C 1 to C n stations, retransmitters are deployed to relay the signal. The present invention introduces three cases to illustrate the evaluation of system performance metrics (including reliability, expected fraction of acceptable signals, and cost), the optimal allocation of connection elements for the full-node LMCCS, and the joint optimization of CE allocation considering node construction.

[0049] Case 1: Evaluate the performance metrics of LMCCS

[0050] In a full-node LMCCS consisting of three locations, a type 1 CE is deployed on the first node, and a type 2 CE is deployed on the second node. The third node is a convergence node that receives signals from the first two nodes and does not need to deploy a CE. In this case, the type 1 CE has better performance than the type 2 CE, and each type of CE has two working states, as shown in the following table:

[0051] Table 1 Costs, Performance, and Occurrence Probabilities of Different Types of CEs

[0052]

[0053] The UGF information matrix of the first node is as follows:

[0054]

[0055] The UGF information matrix of the entire LMCCS is as follows:

[0056]

[0057] If the system is to be reliable, the minimum requirement for the fraction of signals that the receiver can receive is 0.8. After calculation, the reliability of the system is 0.48 + 0.32 = 0.8. The expected fraction of signals that the aggregation node can receive is 0.8072. In this example, it is assumed that the cost of establishing one node is 1.5, and the total cost of the system is 1.5 + 2 + 1.5 + 1 = 6.

[0058] Example 2: Allocation of Optimal CEs

[0059] In a full-node LMCCS consisting of nine positions, two types of CEs are allocated to each of the first eight nodes, and only one CE is deployed on each node. The aggregation node (the 9th node) is responsible for receiving all the signals sent by the first eight nodes. Similar to Example 1, CE of type 1 has better performance than CE of type 2, and each CE has two working states. The UGF information matrices of the two types of CEs are as follows:

[0060]

[0061]

[0062] The costs of different CEs and the construction costs of nodes in this example are the same as those in Example 1. As an example of an optimization problem that takes into account reliability, expected fraction of received signals, and cost, the present invention has found a solution that minimizes the total cost under two constraints: reliability (R * = 0.95) and expected fraction of received signals (E * = 0.9). There are a total of 256 allocation schemes, and 54 of them can meet the constraints of R and E, as shown in the following table.

[0063] Table 2 Allocation Schemes in Example 2 That Meet the Requirements of Reliability Higher than 0.95 and Expected Signal Fraction Greater than 0.9

[0064]

[0065]

[0066] It can be seen that the optimal allocation strategy in this example is to deploy CEs of type 1 at the first 4 nodes and CEs of type 2 at the last 4 nodes. The corresponding system reliability is 0.9708569, the expected signal score is 0.908898, and the cost is 24. The results show that it is recommended to deploy CEs of type 1 at the front-end nodes and CEs of type 2 at the back-end nodes of the sequence. This is more in line with the actual requirements because the later nodes only need to connect to fewer subsequent nodes, and it is more cost-effective to use better CEs at the nodes in the front of the sequence.

[0067] Example 3: Optimizing the Allocation of CEs and Node Construction

[0068] On the basis of Example 2, this example is further extended to consider whether to construct nodes at each position, and to co-optimize node construction and CE allocation to achieve higher reliability and transmit more signals at lower cost. In the LMCCS composed of nine positions, two types of CEs are selected for the node at the first position, and the nodes at the following 7 positions can choose to have no node or deploy different types of CEs. The conditions such as the performance and construction cost of CEs in this example are the same as those in Example 2. There are a total of 4374 different designs in this example. Using the model of the present invention, the reliability, expected received signal score, and cost of these system designs are calculated as shown in the following table.

[0069] Table 3 Allocation Schemes in Example 3 that Meet the Requirements of Reliability Higher than 0.95 and Expected Signal Score Greater than 0.9

[0070]

[0071]

[0072]

[0073] It can be seen that under the conditions of meeting R * = 0.95 and E * = 0.9, the optimal system design with the minimum cost is to construct nodes at all positions except positions 5 and 8, and deploy CEs of type 1 on all constructed nodes. For the optimal design, the corresponding reliability and expected received signal score are 0.951552 and 0.904262 respectively, slightly less than 0.9708569 and 0.908898 in Example 2. However, the cost of the optimal system design in this example is lower than that in Example 2 (21 vs 24). Obviously, although the performance of the LMCCS is affected by its empty positions, the cost is also reduced while meeting the requirements of reliability and expected received signal score.

[0074] The above content is only a preferred embodiment of the present invention and does not limit the protection scope of the present invention. Within the technical field disclosed by the present invention, any person skilled in the art can easily think of changes or substitutions to the technical scope, and these changes or substitutions should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope clearly defined in the claims.

Claims

1. An economic design method for a Linear Multimorphic Continuous Connection System (LMCCS) considering cost and signal loss, characterized in that: It includes the following steps: Step 1: Collect data such as the costs and performance data of different types of connection elements (CEs) (i.e., the signal fractions transmitted by different CEs to different distances), node construction costs, etc. Step 2: Select to use the Universal Generating Function (UGF) method to construct the expected signal fraction reception models of nodes and subsystems in the LMCCS, and measure the expected signal fractions received by the CEs from different distances under different working conditions. Step 3: Establish the expected signal fraction reception models of the full nodes and the LMCCS considering node construction respectively, and measure the expected signal fractions received by the CEs from different distances under different working conditions. Step 4: According to the known expected signal reception model of the LMCCS, measure the expected signal fraction finally received by the aggregation node of the system, system reliability, and cost.

2. The economic design method for an LMCCS considering cost and signal loss according to claim 1, characterized in that, in the said Step 1, the received signal fraction capabilities of different CEs, the costs of different CEs, node construction costs, and the minimum requirements for the signal fractions that the receiver can receive are defined through data collection.

3. The economic design method for an LMCCS considering cost and signal loss according to claim 1, characterized in that, in the said Step 2, the expected signal fraction reception model of the nodes in the LMCCS is defined as: In the formula, is node C i UGF of the performance distribution; C i is the node at position i; is node C i the probability of being in state k, where is node C i the number of different states; is the signal fraction transmitted when node C i is in state k, where z is an indicator variable without practical significance.

4. The economic design method for an LMCCS considering cost and signal loss according to claim 1, characterized in that, in the said Step 2, the expected signal fraction reception model of the subsystems in the LMCCS is defined as: In the formula, is the UGF of the performance distribution of subsystem S i-1 ; is the number of different states of subsystem S i-1 ; is the probability that subsystem S i-1 is in state k. is the fraction of the signal transmitted when subsystem S i-1 is in state k, where 5. The economic design method for an LMCCS considering cost and signal loss according to claim 1, characterized in that, in the said Step 3, the expected signal fraction reception model of the full nodes of the LMCCS is defined as: wherein, is the UGF of the performance distribution of system S i ; is the signal fraction of subsystem S i-1 transmitted to connection range l, where l = 1,..., N - i + 1 and 6. The economic design method for an LMCCS considering cost and signal loss according to claim 1, characterized in that, in the said Step 3, the expected signal fraction reception model of the LMCCS considering node construction is defined as: In the formula, denotes the combination of S i-1 and the empty position i without a constructed node to obtain S i . If the position i is empty, the signal score of S i is still the same as that of S i-1 , but its position i should be excluded from the connection range of S i . Through iteration, the expected signal score receiving model of S i under the consideration of node construction is as follows: where b i is a Boolean variable indicating whether to construct a node at position i (b i = 1) or not to construct a node (b i = 0), where i = 1, ..., N + 1.

7. The economic design method for an LMCCS considering cost and signal loss according to claim 1, characterized in that, in the said Step 4, the expected signal fraction finally received by the aggregation node of the system, system reliability, and cost are respectively defined as: Using this iterative method, the S of LMCCS considering node construction is obtained N (i = N) The expected signal score reception model is as follows: In the formula, is the UGF of the system's performance distribution. The receiver receives the following expected signal fractions transmitted from the nodes constructed in the LMCCS: where E is the expected received signal fraction of the sink node C N+1 The reliability of the system is as follows: where R is the reliability of the LMCC under consideration; δ is to judge whether the satisfies the minimum requirement r in state k. If is true, then 1(x k ≥ w) = 1; otherwise 1(x k ≥ w) = 0. The cost calculation of the LMCCS is as follows: Wherein, TC is the total cost of LMCCS; h i is the type of CE deployed at node C i . is the cost required for the CE deployed at node C i ; V C is the cost of building a node. The balance is achieved by calculating three performance metrics (system cost, reliability, and expected received signal fraction) to minimize the system cost and ensure its operation in the most economical and efficient way.

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