CN106793151A - Distributed random handshake method and its system in a kind of wireless built network - Google Patents

Abstract

The present invention discloses a distributed random handshake method and system in a wireless embedded network. The method includes: Step 1. In the tth time slot, detect all accessible channels of the terminal equipment to form the accessible channels of the terminal equipment. access channel set; step 2, according to the historical availability of each channel in the terminal equipment accessible channel set, arrange each channel in order to form a terminal equipment accessible channel sequence arrangement set; step 3, for the described Each channel in the sequentially arranged set of channels that the terminal device can access is assigned an access selection probability; step 4, select each channel in the sequentially arranged set of channels that the terminal device can access according to the access selection probability, and try to shake hands until the handshake If successful, otherwise return to step 1 and make t=t+1. The technical scheme provided by the invention can effectively enable the communication terminal to realize handshaking between devices and thus realize smooth and effective communication when the wireless channel dynamic change environment causes the dynamic change of the accessable channel.

Description

Distributed random handshake method and system in wireless embedded network

technical field

The invention relates to the technical field of wireless embedded network communication, in particular to a distributed random handshake method and system in a wireless embedded network.

Background technique

Embedded system (Embedded System) is a kind of computer system with specific functions centered on micro control unit. With the popularity and development of the Internet of Things, embedded systems are widely used in industrial control, e-commerce, information appliances and other fields, and the requirements for wireless communication between embedded terminal devices are getting higher and higher. Therefore, wireless embedded The research on the communication technology of Wireless Embedded Networks (WENs) is one of the important topics in this field.

The wireless embedded network is composed of embedded terminal devices (Embedded Terminal Device, ETD). Through wireless communication technology, terminal devices realize communication by accessing wireless channels decomposed by available spectrum. Wireless communication has a great impact on the normal operation of wireless embedded networks. play a key role. During the communication process, the embedded terminal device perceives the available state of the spectrum, accesses an accessible wireless channel through frequency hopping (Channel Hopping, CH) technology, and communicates with other embedded terminal devices accessing the same channel , we refer to embedded terminal devices accessing the same channel through frequency hopping technology as handshaking. Only through handshaking can the corresponding communication link be established between embedded terminal devices, and then the communication can be realized. Therefore, the handshake method is the most important. Researching the handshake problem in the wireless embedded network has important practical significance for improving the performance of the wireless embedded network.

According to different network structures, handshake methods in wireless embedded networks can be divided into centralized and distributed. Most of the centralized handshake methods require a pre-configured central controller and a control channel to realize the handshake between wireless communication devices. However, the dynamic characteristics of wireless embedded networks make the centralized handshake method difficult to implement.

Unlike the centralized handshaking method, the distributed handshaking method does not use any central controller to assist handshaking, thus avoiding single point of failure and congestion on the control channel. However, most of the current research on the handshake problem in wireless embedded networks only considers the case that the accessible channel is in a stable state, but the actual situation is that the accessible channel of ETD will change with time and place, and the wireless channel environment has Dynamically changing characteristics, for example, due to interference caused by channel occupancy by nearby devices, some originally accessible channels become unusable, thereby affecting communication between devices.

Therefore, the prior art still needs to be improved and developed.

Contents of the invention

In view of the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a distributed random handshake method and system in a wireless embedded network, aiming at solving the problem of the dynamic change of distributed accessible channels in the wireless embedded network affecting the equipment communication problem.

The technical scheme that the present invention adopts is as follows:

A distributed random handshake method in a wireless embedded network, comprising the following steps:

Step 1. In the tth time slot, detect all accessible channels of the terminal equipment to form a set of accessible channels of the terminal equipment;

Step 2, according to the historical availability of each channel in the set of channels accessible to the terminal equipment, arrange each channel in order to form a sequential arrangement set of channels accessible to the terminal equipment;

Step 3, assigning an access selection probability to each channel in the sequentially arranged set of channels accessible to the terminal device;

Step 4. According to the access selection probability, select each channel in the sequentially arranged set of channels accessible to the terminal device to try handshaking until the handshake succeeds, otherwise return to step 1, and set t=t+1.

Distributed random handshake method in the described wireless embedded network, wherein, described step 1 comprises:

Step 11, counting the total number of accessible channels in the wireless embedded network;

Step 12. In the tth time slot, detect all accessible channels of the terminal equipment in the wireless embedded network, and form a set of accessible channels of the terminal equipment, expressed by the following formula:

Formula (1) is a Boolean vector, which represents the accessible channels of the terminal device A in the tth time slot, where n represents the total number of accessible channels in the wireless embedded network, and t represents the tth time slot slot, t=1,2,...,∞, c _i represents the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot;

In formula (2) Indicates the set of accessible channels of terminal device A in the tth time slot, c _i indicates the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot.

Distributed random handshake method in the described wireless embedded network, wherein, described step 2 specifically comprises:

Step 21. Calculate the historical availability of the _i -th channel ci for the terminal equipment A in the t-th time slot The calculation formula is:

In the formula (3), t' is an integer of (1, t), which means the t'th time slot.

Step 22, forming a set of historical availability ratios of channel _ci for terminal equipment A in the tth time slot

Step 23, the described The channel elements in , according to the historical availability of each channel _ci Arrange in descending or ascending order to obtain the sequenced set of channels that terminal device A can access which is Among them, the channel ..., c _i , c _j , c _k , ..., the corresponding channel historical availability ratio relationship is or

Distributed random handshake method in the described wireless embedded network, wherein, described step 11 is specifically:

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in, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot.

Distributed random handshake method in the described wireless embedded network, wherein, described step 3 is specifically:

The method for calculating the access selection probability of each channel in the sequentially arranged set of channels that terminal equipment can access is as follows: Set the sequentially arranged set of channels that terminal equipment A can access according to The historical availability rate corresponding to the accessible channel in As the weight assignment probability, the calculated probabilities of channels ..., c _i , c _j and c _k ..., being selected are respectively with and

Distributed random handshake method in the described wireless embedded network, wherein, described step 3 is specifically:

Each channel in the sequentially arranged set of channels that terminal device A can access is assigned the access selection probability based on the class exponential distribution.

e ^j-1 (6);

Formula (6) expresses The jth channel element assigns weights in

Formula (7) shows The probability that the jth channel element is selected in

where e is Euler's number.

Distributed random handshake method in the described wireless embedded network, wherein, described step 3 is specifically:

Each channel in the sequentially arranged set of channels that terminal device A can access is assigned the access selection probability based on the class geometric distribution.

λ(1-λ) ^j-1 (8);

Formula (8) expresses The distribution weight of the jth channel element in , where, λ∈(0,1) is a constant parameter of the standard geometric distribution;

Formula (9) expresses The probability of being selected corresponding to the jth channel element in

A distributed random handshake system in a wireless embedded network, comprising:

A detection module, configured to detect all accessible channels of the terminal equipment in the tth time slot to form a set of accessible channels of the terminal equipment;

A sorting module, configured to arrange each channel in sequence according to the historical availability of each channel in the set of channels accessible to the terminal device to form a sequential arrangement set of channels accessible to the terminal device;

A selection probability allocation module, configured to allocate an access selection probability to each channel in the sequentially arranged set of accessible channels for the terminal device;

The handshaking module is used to select each channel in the sequentially arranged set of channels accessible to the terminal device according to the access selection probability, and try to handshake until the handshake is successful, otherwise return to the detection module and set t=t+1.

Distributed random handshake system in the described wireless embedded network, wherein, the described detection module comprises:

A statistical unit, used to count the total number of accessible channels in the wireless embedded network;

The detection unit is used to detect all accessible channels of the terminal equipment in the wireless embedded network in the tth time slot, and form a set of accessible channels of the terminal equipment, expressed by the following formula:

Formula (1) is a Boolean vector, which represents the accessible channels of the terminal device A in the tth time slot, where n represents the total number of accessible channels in the wireless embedded network, and t represents the tth time slot slot, t=1,2,...,∞, c _i represents the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot;

In formula (2) Indicates the set of accessible channels of terminal device A in the tth time slot, c _i indicates the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot.

Distributed random handshake system in the described wireless embedded network, wherein, the described ordering module comprises:

A calculation unit, used to calculate the historical availability of the _i -th channel ci for the terminal device A in the t-th time slot The calculation formula is:

In the formula (3), t' is an integer of (1, t), which means the t'th time slot.

The channel historical availability collection unit is used to form the historical availability collection of the channel _ci for the terminal device A in the tth time slot

sorting unit for the The channel elements in , according to the historical availability of each channel _ci Arrange in descending or ascending order to obtain the sequenced set of channels that terminal device A can access which is Among them, the channel ..., c _i , c _j , c _k , ..., the corresponding channel historical availability ratio relationship is or

The described selection probability distribution module includes:

The first calculation unit of selection probability is used for the calculation method of each channel allocation access selection probability in the sequential arrangement set of accessible channels of the terminal equipment as follows: suppose that the terminal equipment A can access the sequential arrangement set of channels according to The historical availability rate corresponding to the accessible channel in As the weight assignment probability, the calculated probabilities of channels ..., c _i , c _j and c _k ..., being selected are respectively with and

The second calculation unit of selection probability is used for each channel in the sequentially arranged set of accessible channels for terminal equipment A.

e ^j-1 (6);

Formula (6) expresses The jth channel element assigns weights in

Formula (7) shows The probability that the jth channel element is selected in

Among them, e is Euler's number;

The third calculation unit of selection probability is used for assigning access selection probability to each channel in the sequentially arranged set of channels that terminal equipment A can access.

λ(1-λ) ^j-1 (8);

Formula (8) expresses The distribution weight of the jth channel element in , where, λ∈(0,1) is a constant parameter of the standard geometric distribution;

Formula (9) expresses The probability of being selected corresponding to the jth channel element in

Beneficial effects: Compared with the prior art, the present invention provides a distributed random handshake method in a wireless embedded network and its system, aiming at the characteristics of the dynamic change of the wireless channel environment in the wireless embedded network and the distributed characteristics of the network, A heuristic-based distributed handshake method for embedded terminal devices is proposed. The method utilizes the historical availability of wireless channels, and by reasonably assigning random selection probabilities to currently available channels, wireless embedded terminal devices at each time The chip randomly selects and accesses a certain channel, and tries to shake hands on the channel, which can effectively enable the intended communication terminal device to achieve handshake between devices under the condition that the accessable channel changes dynamically, thereby realizing smooth and effective communication.

Description of drawings

Fig. 1 is the flow chart of a preferred embodiment of the distributed random handshake method in the wireless embedded network provided by the present invention

Fig. 2 is a functional block diagram of a preferred embodiment of a distributed random handshake system in a wireless embedded network provided by the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention more clear and definite, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The present invention proposes a distributed handshake method based on a heuristic algorithm for embedded terminal devices in a distributed channel dynamic environment in a wireless embedded network by counting channel states, and analyzes the effectiveness of the method through simulation experiments, as follows Explain in detail.

Please refer to Fig. 1, Fig. 1 is a flow chart of a preferred embodiment of the distributed random handshake method in the wireless embedded network provided by the present invention, comprising steps:

S100. In the tth time slot, detect all channels accessible to the terminal device to form a set of channels accessible to the terminal device;

Describe it with a mathematical problem. For example, in a wireless embedded network, if there are two embedded terminal devices A and B, it is intended to establish a communication link by accessing the same wireless channel. Channel set C={c ₁ ,c ₂ ,...,c _n }, where, represents the i-th channel. Without loss of generality, we assume that the wireless channels are orthogonal in pairs (orthogonal frequency division multiplexing technology, that is, Orthogonal Frequency Division Multiplexing, OFDM, is to divide the channel into several orthogonal sub-channels, and convert high-speed data signals into parallel low-speed sub-channels. The data stream is modulated to be transmitted on each sub-channel.), we discretize the time as time slices of equal length, use t to represent the tth time slice, and use Δt to represent the length of each time slice, the The time length Δt of can be pre-determined according to needs, then the tth time slice is within the tth time slot. It should be noted that the time slice, that is, the length of the slot, can be specifically set according to the needs of different actual environments, and is not limited here.

At the same time, considering the dynamic characteristics of the channel, let the Boolean variable with Respectively: in the tth time slice, channel c _i is accessible to terminal equipment A and B, for example, Indicates that channel _ci can be accessed by terminal device A in the tth time slot. For any time slot t, the terminal device A (or B) selects a current accessible channel (ie frequency hopping operation) and tries to shake hands. We use δ to denote the minimum time required by any user pair from attempting to shake hands to successfully shaking hands, then Δt≥δ. It can be known from the distributed nature of the wireless embedded network that the terminal devices A and B only know the conditions of their respective accessible channels. We call it a successful handshake. If and only if terminal devices A and B select the same channel, for example, select channel _ci at the same time, then terminal devices A and B can successfully handshake to achieve communication. We assume that at any moment there is at least one same accessible channel for terminal devices A and B.

During implementation, this step S100 specifically includes:

S110, counting the total number of accessible channels in the wireless embedded network;

S120. In the tth time slot, detect all accessible channels of the terminal equipment in the wireless embedded network, and form a set of accessible channels of the terminal equipment, which is expressed by the following formula:

Formula (1) is a Boolean vector, which represents the accessible channels of the terminal device A in the tth time slot, where n represents the total number of accessible channels in the wireless embedded network, and t represents the tth time slot slot, t=1,2,...,∞, c _i represents the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot;

In formula (2) Indicates the set of accessible channels of terminal device A in the tth time slot, c _i indicates the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot.

During specific implementation, in practical applications, the total number n of accessible channels in the wireless embedded network depends on the specific application system environment, and the number of channels n depends on factors: 1), the available frequency band range; 2), each channel The allocated frequency band bandwidth. For example, in the WiFi scenario of embedded devices, the frequency band of the 802.11b/g/n protocol is 2.412Ghz-2.472Ghz, a total of 60Mhz, and the available frequency band of 802.11a/n in China is 5.745Ghz-5.825Ghz, which is also 60Mhz. Here, if a channel is 20MHz, then there are only about 3 channels; if a channel is allocated 10MHz, then there are about 6 channels, so the channel is fixed in each system, and only needs to be detected and counted in the specific system environment. Yes, no more details here.

Detecting whether the channel in the wireless embedded network is accessible within the tth time slot can be judged by using the existing technology, and will not be repeated here.

S200. According to the historical availability rate of each channel in the channel set accessible to the terminal device, arrange each channel in order to form a sequential arrangement set of channels accessible to the terminal device;

Based on the characteristics of wireless embedded networks, this patent application proposes a distributed adaptive random handshake method under the environment of dynamic wireless channel changes. Under the handshake method, at the beginning of each time slice, that is, at the beginning of each time slot, each The embedded terminal device first counts the historical access times of n channels, based on the historical access frequency of each channel, that is, the historical opening rate of the channel, assigns the probability of random selection to the currently accessible channel, and finally based on the The random selection probability distribution randomly selects a channel for a handshake attempt. Specifically, the step S200 includes:

S210. Calculate the historical availability of the _i -th channel ci for the terminal device A in the t-th time slot The calculation formula is:

In the formula (3), t' is an integer of (1, t), which means the t'th time slot.

S220, forming a set of historical availability ratios of channel _ci for terminal device A in the tth time slot

S230, the said The channel elements in , according to the historical availability of each channel _ci Arrange in descending or ascending order to obtain the sequenced set of channels that terminal device A can access which is Among them, the channel ..., c _i , c _j , c _k , ..., the corresponding channel historical availability ratio relationship is or

Further, the step S210 is specifically:

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in, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot.

During implementation, it is preferable to use the historical availability of each channel _ci Arrange in descending order to obtain the orderly arrangement set of channels that terminal device A can access In this way, it is beneficial to preferentially select a channel with a high probability of handshake success in the subsequent steps to try, thereby shortening the time required by any user from trying to handshake to successfully handshaking as much as possible, and more conducive to improving the efficiency of communication between terminal devices.

S300. Allocate an access selection probability for each channel in the sequentially arranged set of channels accessible to the terminal device;

For example, orderly arrange the set of channels accessible to the terminal device A Each channel in the distribution access selection probability, which is the core step of this technical solution, is based on the size of the access selection probability, and then analyzes and determines which channel can make the handshake between terminal devices have a higher probability of success, so as to choose which The channel tries to shake hands to improve the probability of successful channel selection between terminal devices.

Specifically, there are three specific schemes for assigning access selection probabilities for each channel in the step S300, and during specific implementation, one of them can be arbitrarily selected according to actual needs, which are discussed in detail below:

Scheme ①. The method for calculating the access selection probability of each channel in the sequentially arranged set of accessible channels for terminal equipment is as follows: Set the sequentially arranged set of accessible channels for terminal equipment A according to The historical availability rate corresponding to the accessible channel in As the weight distribution probability, the calculated probabilities of ..., c _i , c _j and c _k ..., are respectively with and

This access selection probability allocation method is based on The historical availability rate corresponding to the medium channel element As a weight distribution probability, the following example illustrates, if Contains 3 channels c _i , c _j , c _k , which can be calculated and arranged according to their respective channel historical availability ratios Take descending order as an example, that is, we will As a weight for linear normalization, the calculated probabilities of c _i , c _j and c _k are respectively with This is actually a normalization process, so this distribution can guarantee The sum of the probabilities of the elements in is 1. In the above example, obviously, we know In the follow-up simulation experiment, the descending order is taken as an example to verify the validity of the channel allocation access selection probability.

Scheme ②, each channel in the sequentially arranged set of channels that terminal equipment A can access is assigned the access selection probability based on the class exponential distribution.

e ^j-1 (6);

Formula (6) expresses The jth channel element assigns weights in

Formula (7) shows The probability that the jth channel element is selected in

where e is Euler's number.

It should be noted that the reason why it is called "exponential-like distribution" is because The number of elements in is limited, and the exponential distribution in the usual sense considers an infinite range of random variables.

Specifically, based on the exponential distribution, the access channel of A is randomly selected to access the probability, first for The jth element (channel) in the assignment weight e ^j-1 , Among them, e is the Euler number; after allocating the weights, the random selection probability of each channel is calculated through normalization processing, then the selection probability corresponding to the jth element is This way can guarantee The probability sum of the elements in is equal to 1, thus ensuring that the selected channel belongs to The effectiveness of this channel allocation access selection probability will be verified in subsequent simulation experiments.

Scheme ③. Each channel in the sequentially arranged set of channels that terminal device A can access is allocated and selected based on the class geometric distribution. The calculation method is as follows: Set the sequenced set of channels that terminal device A can access

λ(1-λ) ^j-1 (8);

Formula (8) expresses The distribution weight of the jth channel element in , where, λ∈(0,1) is a constant parameter of the standard geometric distribution;

Formula (9) expresses The probability of being selected corresponding to the jth channel element in

Again, the reason it's called a "geometric-like distribution" is because The number of elements in is limited, and the geometric distribution in the usual sense considers an infinite range of random variables.

This access selection probability allocation method is based on the access channel with class geometric distribution A to allocate the probability of random access selection. Specifically, first The distribution weight λ(1-λ) ^j-1 of the jth element (channel) in Among them, λ∈(0,1) is a constant parameter of the standard geometric distribution; after the weights are assigned, the random selection probability of each channel is calculated through normalization processing to ensure that The probability sum of the elements in is equal to 1, and the probability corresponding to the jth element is This way can guarantee The probability sum of the elements in is equal to 1, thus ensuring the effectiveness of the scheme. The effectiveness of this channel allocation access selection probability will be verified in subsequent simulation experiments.

S400. Select each channel in the sequentially arranged set of channels accessible to the terminal device according to the access selection probability, and try to handshake until the handshake is successful; otherwise, return to step S100, and set t=t+1.

During specific implementation, for example, arrange the sets according to the sequence of channels accessible by the terminal device A The access selection probability distribution for each channel assignment in is selected one by one in order The channels in , generally, try according to the access selection probability from large to small, and try to shake hands on the selected channel. If terminal device A and terminal device B can access the same channel at the same time to establish a communication connection, then terminal device A and terminal device B successfully shake hands; None of the channels can make terminal equipment A and terminal equipment B access the same channel at the same time, then the handshake is not successful, indicating that in the same tth time slot, terminal equipment A and terminal equipment B do not have the same channel that can be accessed, then Return to step S100, let t=t+1 enter the next cycle and continue trying until terminal device A and terminal device B try to shake hands and successfully establish a communication connection.

In order to understand this technical solution more clearly and verify the feasibility and effectiveness of the wireless embedded network handshake method, the MATLAB programming language is used to simulate the handshake situation in the real wireless embedded network, and the above technical solution is simulated and tested. The advantages and disadvantages of the three methods of assigning access selection probability for each channel can be compared, and the specific process is as follows:

(1). Mathematical description of the problem: the description of the mathematical problem is as described above, and will not be repeated here. It should be noted that this simulation experiment selects the handshake time T as an evaluation parameter of a handshake method. Here, T is defined as the number of time slices required from the first simultaneous handshake attempt of terminal devices A and B to the final handshake. Specifically, the expected value E(T) and the maximum value M(T) of the handshake time are considered as an evaluation index of a handshake method.

(2). The basic description of the technical solution of the present invention: the following takes the embedded terminal device A as an example, and provides a specific algorithm description:

Symbol description:

n: the total number of accessible channels in the wireless embedded network;

C: Accessible wireless channel set C={c ₁ ,c ₂ ,...,c _n }, where, Indicates the i-th channel;

c _i : the i-th channel (here we give the corresponding label to the channel);

t: the tth time slice, t=1,2,...,∞;

A Boolean vector representing the situation of A's accessible channels in the tth time slice; for example, Indicates that terminal device A can access channel c ₁ in the tth time slot, It means that the terminal device A cannot access the channel c ₁ in the tth time slot.

In the tth time slice, A’s accessible channel set,

Indicates the number of channels that terminal device A can access in time slice t, that is,

In the tth time slice, the channel availability of terminal device A,

In the tth time slice, the historical availability of channel _ci for terminal equipment A, that is,

A collection of historical availability of the channel,

Algorithm process:

Step 1: Input n and C, initialize t=0,

Step 2: Update the number of time slices t=t+1,

Step 3: Perceive the channel availability and calculate A ^t ;

Step 4: Calculate Here, a memory variable is used to store to reduce space complexity;

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Step 5: According to A ^t , calculate

Step 6: Put The channel elements in , according to their respective channel history availability Sort in descending order, get sorted (here, );

Step 7: For The elements in are assigned the probability of random selection access, and the three methods of assigning access selection probability for each channel in the above step S300 are used as three probability allocation schemes;

Step 8: Select one by one in order according to the probability distribution in step 7 In this simulation experiment, the probability is from large to small, and a handshake is attempted on the selected channel;

Step 9: If the handshake is not implemented, then execute Step 2; otherwise, end the algorithm.

(3). Simulation experiment and result analysis: Let the total number of channels be n, without loss of generality, assuming that for any t, That is, in any time slice, the number of accessible channels of A and B is the same and constant (but the set of accessible channels is not necessarily the same), that is, the channel availability In order to simulate the dynamic change characteristics of the access channel set in different handshake scenarios in the wireless embedded network in the real environment, we introduce the experimental parameter of channel dynamic change rate η, so as to simulate different channel sets in different experimental environments in a large number of experiments , respectively verifying the effectiveness of the technical solution of the present invention under different channel sets, thereby verifying the effectiveness of the technical solution of the present invention in different handshake scenarios caused by dynamic changes in the channel environment in actual communication.

We compare the number of accessible channels changed in each time slot (compared with the previous time slot) to the total number of accessible channels, and define it as channel dynamic change rate η. Without loss of generality, we assume that η is constant. In the simulation experiment, at the tth time slice (taking A as an example), we equally probabilistically start from choose from channel, so that it is still available in the t+1th time slice; at the same time, from the set with equal probability choose from channel, available in the t-1th time slice. These selected channels will appear in the middle. At the beginning of each time slice (take the tth time slice as an example), we compare with if In order to ensure that A and B have a chance to successfully shake hands in this time slice, we replace or An element (channel) in such that Among them, it should be noted that, The situation rarely occurs in reality; moreover, if Then the algorithm of the present invention will lose the basic feasible premise, and will not consider this situation.

According to the availability of the channel, we can divide the embedded terminal equipment into two types: symmetrical and asymmetrical. For symmetrical embedded terminal devices, their channel availability in each time slice is the same, that is, For asymmetric embedded terminal devices, in the same time slice, with may be different. Because both symmetric and asymmetric situations may occur in the actual scene, it is necessary to experiment and analyze their situations in the simulation experiment.

As mentioned above, the evaluation index of the algorithm performance is the expected value E(T) and the maximum value M(T) of the handshake time. Because there is randomness in the experimental settings and algorithms, in order to obtain more objective results, the present invention calculates E(T) and M(T) through a large number of experiments, that is, repeats each experiment 500 times, and verifies the three proposed in the present invention. The effectiveness of a probability assignment scheme.

Under symmetrical and asymmetrical terminal equipment, three kinds of probability allocation schemes proposed by the present invention were tested, and the experimental results were obtained as shown in Tables 1-6 below:

Table 1. Simulation experiment results of implementation scheme ① of wireless embedded symmetrical terminal equipment

Table 2. Simulation experiment results of wireless embedded asymmetric terminal equipment execution scheme ①

Table 3. The simulation experiment results of the wireless embedded symmetric terminal equipment execution scheme ②

Table 4. Simulation results of wireless embedded asymmetric terminal equipment execution scheme ②

Table 5. The simulation experiment results of the wireless embedded symmetrical terminal equipment execution scheme ③

Table 6. Simulation results of wireless embedded asymmetric terminal equipment execution scheme ③

From the experimental results, it can be observed that all the experiments have successfully achieved the handshake, which shows that the three probability allocation schemes of the wireless embedded network proposed by the present invention are effective methods for the dynamic change of the channel environment.

Please refer to Fig. 2, Fig. 2 is the functional block diagram of the preferred embodiment of the distributed random handshake system in the wireless embedded network provided by the present invention, including:

The detection module 10 is configured to detect all accessible channels of the terminal device in the tth time slot to form a set of accessible channels of the terminal device, specifically as described in the above method;

The sorting module 20 is configured to arrange each channel in order according to the historical availability of each channel in the set of channels accessible to the terminal device to form a sequential arrangement set of channels accessible to the terminal device, specifically as described in the above method;

A selection probability allocation module 30, configured to allocate access selection probabilities to each channel in the sequentially arranged set of channels accessible to the terminal device, specifically as described in the above method;

The handshake module 40 is used to select each channel in the sequentially arranged set of accessible channels of the terminal device according to the access selection probability to try to shake hands until the handshake is successful, otherwise return to the detection module and make t=t+1, specifically as described above method.

Distributed random handshake system in the described wireless embedded network, wherein, described detection module 10 comprises:

A statistical unit, configured to count the total number of accessible channels in the wireless embedded network, specifically as described in the above method;

The detection unit is used to detect all accessible channels of the terminal equipment in the wireless embedded network in the tth time slot, and form a set of accessible channels of the terminal equipment, expressed by the following formula:

Formula (1) is a Boolean vector, which represents the accessible channels of the terminal device A in the tth time slot, where n represents the total number of accessible channels in the wireless embedded network, and t represents the tth time slot slot, t=1,2,...,∞, c _i represents the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot;

In formula (2) Indicates the set of accessible channels of terminal device A in the tth time slot, c _i indicates the i-th channel, Indicates that the terminal device A can access the channel c _i in the tth time slot, specifically as described in the above method.

Distributed random handshake system in the described wireless embedded network, wherein, the described sorting module 20 comprises:

A calculation unit, used to calculate the historical availability of the _i -th channel ci for the terminal device A in the t-th time slot The calculation formula is:

In the formula (3), wherein, t' is an integer of (1, t), which means the t'th time slot, specifically as described in the above method;

The channel historical availability collection unit is used to form the historical availability collection of the channel _ci for the terminal device A in the tth time slot Specifically as described above;

sorting unit for the The channel elements in , according to the historical availability of each channel _ci Arrange in descending or ascending order to obtain the sequenced set of channels that terminal device A can access which is Among them, channel..., _{ci ,c j ,} c _k ,..., the corresponding channel historical availability ratio relationship is or Specifically as described above.

Described selection probability assignment module 30 comprises:

The first calculation unit of selection probability is used for the calculation method of each channel allocation access selection probability in the sequential arrangement set of accessible channels of the terminal equipment as follows: suppose that the terminal equipment A can access the sequential arrangement set of channels according to The historical availability rate corresponding to the accessible channel in As the weight distribution probability, the calculated probabilities of ..., c _i , c _j and c _k ..., are respectively with and

Specifically as described above;

The second calculation unit of selection probability is used for each channel in the sequentially arranged set of accessible channels for terminal equipment A.

e ^j-1 (6);

Formula (6) expresses The jth channel element assigns weights in

Formula (7) shows The probability that the jth channel element is selected in Wherein, e is Euler's number, specifically as described in the above method;

The third calculation unit of selection probability is used for assigning access selection probability to each channel in the sequentially arranged set of channels that terminal equipment A can access.

λ(1-λ) ^j-1 (8);

Formula (8) expresses The distribution weight of the jth channel element in , where, λ∈(0,1) is a constant parameter of the standard geometric distribution;

Formula (9) expresses The probability of being selected corresponding to the jth channel element in

To sum up, the distributed random handshake method and its system in the wireless embedded network provided by the present invention aim at the distributed handshake self-adaption of the embedded terminal equipment under the dynamic environment of the distributed wireless accessible channel in the wireless embedded network. The random handshake method, through statistical channel status, proposes a heuristic-based distributed handshake method for embedded terminal equipment, which can effectively enable the intended communication terminal equipment to achieve handshake between devices under the condition of dynamic changes in the access channel and thus achieve smooth communication. Communicate effectively.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be realized by instructing related hardware (such as processors, controllers, etc.) through computer programs, and the programs can be stored in a computer. In the read storage medium, the program may include the processes of the above-mentioned method embodiments when executed. The storage medium mentioned herein may be a memory, a magnetic disk, an optical disk, and the like.

It should be understood that the application of the present invention is not limited to the above examples, and those skilled in the art can make improvements or transformations according to the above descriptions, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (10)

1. a distributed random handshake method in a wireless embedded network, characterized in that, comprising the following steps: Step 1. In the tth time slot, detect all accessible channels of the terminal equipment to form a set of accessible channels of the terminal equipment; Step 2, according to the historical availability of each channel in the set of channels accessible to the terminal equipment, arrange each channel in order to form a sequential arrangement set of channels accessible to the terminal equipment; Step 3, assigning an access selection probability to each channel in the sequentially arranged set of channels accessible to the terminal device; Step 4. According to the access selection probability, select each channel in the sequentially arranged set of channels accessible to the terminal device to try handshaking until the handshake succeeds, otherwise return to step 1 and set t=t+1. 2. distributed random handshake method in the wireless embedded network according to claim 1, is characterized in that, described step 1 comprises: Step 11, counting the total number of accessible channels in the wireless embedded network; Step 12. In the tth time slot, detect all accessible channels of the terminal equipment in the wireless embedded network, and form a set of accessible channels of the terminal equipment, expressed by the following formula: ${\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ ${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; \&ForAll;</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; :</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ Formula (1) is a Boolean vector, which represents the accessible channels of the terminal device A in the tth time slot, where n represents the total number of accessible channels in the wireless embedded network, and t represents the tth time slot slot, t=1,2,...,∞, c _i represents the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot; In formula (2) Indicates the set of accessible channels of terminal device A in the tth time slot, c _i indicates the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot. 3. distributed random handshake method in the wireless embedded network according to claim 2, is characterized in that, described step 2 specifically comprises: Step 21. Calculate the historical availability of the _i -th channel ci for the terminal equipment A in the t-th time slot The calculation formula is: In the formula (3), t' is an integer of (1, t), which means the t'th time slot. Step 22, forming a set of historical availability ratios of channel _ci for terminal equipment A in the tth time slot Step 23, the described The channel elements in , according to the historical availability of each channel _ci Arrange in descending or ascending order to obtain the sequenced set of channels that terminal device A can access which is Among them, the channel ..., c _i , c _j , c _k , ..., the corresponding channel historical availability ratio relationship is or 4. distributed random handshake method in the wireless embedded network according to claim 3, is characterized in that, described step 11 is specifically: like but like but in, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot. 5. according to claim 3 or 4 described distributed random handshake methods in the wireless embedded network, it is characterized in that, described step 3 is specifically: The method for calculating the access selection probability of each channel in the sequentially arranged set of channels that terminal equipment can access is as follows: Set the sequentially arranged set of channels that terminal equipment A can access according to The historical availability rate corresponding to the accessible channel in As the weight distribution probability, the calculated probabilities of channels ..., c _i , c _j and c _k ..., being selected are ..., with ...,and 6. according to the distributed random handshake method in the wireless embedded network described in claim 3 or 4, it is characterized in that, described step 3 is specifically: Each channel in the sequentially arranged set of channels that terminal device A can access is assigned the access selection probability based on the class exponential distribution. e ^j-1 (6); ${\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}{\mathrm{<span\; class="notranslate">\; e</span>}}^{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ Formula (6) expresses The jth channel element assigns weights in Formula (7) shows The probability that the jth channel element is selected in where e is Euler's number. 7. according to claim 3 or 4 described distributed random handshake methods in the wireless embedded network, it is characterized in that, described step 3 is specifically: Each channel in the sequentially arranged set of channels that terminal device A can access is assigned the access selection probability based on the class geometric distribution. λ(1-λ) ^j-1 (8); $\mathrm{<span\; class="notranslate">\; \&lambda;</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}\mathrm{<span\; class="notranslate">\; \&lambda;</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span>}^{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ Formula (8) expresses The distribution weight of the jth channel element in , where, λ∈(0,1) is a constant parameter of the standard geometric distribution; Formula (9) expresses The probability of being selected corresponding to the jth channel element in 8. A distributed random handshake system in a wireless embedded network, characterized in that it comprises: A detection module, configured to detect all accessible channels of the terminal equipment in the tth time slot to form a set of accessible channels of the terminal equipment; A sorting module, configured to arrange each channel in sequence according to the historical availability of each channel in the set of channels accessible to the terminal device to form a sequential arrangement set of channels accessible to the terminal device; A selection probability allocation module, configured to allocate an access selection probability to each channel in the sequentially arranged set of accessible channels for the terminal device; The handshaking module is used to select each channel in the sequentially arranged set of channels accessible to the terminal device according to the access selection probability, and try to handshake until the handshake is successful, otherwise return to the detection module and set t=t+1. 9. distributed random handshake system in the wireless embedded network according to claim 8, is characterized in that, described detection module comprises: A statistical unit, used to count the total number of accessible channels in the wireless embedded network; The detection unit is used to detect all accessible channels of the terminal equipment in the wireless embedded network in the tth time slot, and form a set of accessible channels of the terminal equipment, expressed by the following formula: ${\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; ...</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ ${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; \{</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; \&ForAll;</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; :</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \}</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ Formula (1) is a Boolean vector, which represents the accessible channels of the terminal device A in the tth time slot, where n represents the total number of accessible channels in the wireless embedded network, and t represents the tth time slot slot, t=1,2,...,∞, c _i represents the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot, Indicates that terminal device A cannot access channel c _i in the tth time slot; In formula (2) Indicates the set of accessible channels of terminal device A in the tth time slot, c _i indicates the i-th channel, Indicates that terminal device A can access channel c _i in the tth time slot. 10. distributed random handshake system in the wireless embedded network according to claim 8, is characterized in that, described sorting module comprises: A calculation unit, used to calculate the historical availability of the _i -th channel ci for the terminal device A in the t-th time slot The calculation formula is: In the formula (3), t' is an integer of (1, t), which means the t'th time slot. The channel historical availability collection unit is used to form the historical availability collection of the channel _ci for the terminal device A in the tth time slot sorting unit for the The channel elements in , according to the historical availability of each channel _ci Arrange in descending or ascending order to obtain the sequenced set of channels that terminal device A can access which is Among them, the channel ..., c _i , c _j , c _k , ..., the corresponding channel historical availability ratio relationship is or The described selection probability distribution module includes: The first calculation unit of selection probability is used for the calculation method of each channel allocation access selection probability in the sequential arrangement set of accessible channels of the terminal equipment as follows: suppose that the terminal equipment A can access the sequential arrangement set of channels according to The historical availability rate corresponding to the accessible channel in As the weight assignment probability, the calculated probabilities of channels ..., c _i , c _j and c _k ..., being selected are respectively with and The second calculation unit of selection probability is used for each channel in the sequentially arranged set of accessible channels for terminal equipment A. e ^j-1 (6); ${\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}{\mathrm{<span\; class="notranslate">\; e</span>}}^{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ Formula (6) expresses The jth channel element assigns weights in Formula (7) shows The probability that the jth channel element is selected in Among them, e is Euler's number; The third calculation unit of selection probability is used for assigning access selection probability to each channel in the sequentially arranged set of channels that terminal equipment A can access. λ(1-λ) ^j-1 (8); $\mathrm{<span\; class="notranslate">\; \&lambda;</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}\mathrm{<span\; class="notranslate">\; \&lambda;</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span>}^{{\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$ Formula (8) expresses The distribution weight of the jth channel element in , where, λ∈(0,1) is a constant parameter of the standard geometric distribution; Formula (9) expresses The probability of being selected corresponding to the jth channel element in