CN104393968B - Multicast time delay based on binary system molecule traffic model determines method - Google Patents

Abstract

A kind of multicast time delay based on binary system molecule traffic model determines method, comprises the following steps：The first step, analysis link successfully descends the time delay of multicast scene, in binary system molecule traffic model, the transmission of bit 0 or 1 is represented with different molecule types is transmitted, after sender's nano-machines release molecule, molecule is moved in Blang's form in media as well, and for the transmission between two nano-machines of single-link, time delay is defined as recipient's nano-machines and receives the time that at least one molecule averagely needs；Second step, time delay of the analysis single path topological structure under link success；3rd step, analyzing multiple footpath topological structure link success under can time delay；4th step, time delay of the analysis multicast topologies structure under link success.The present invention provides the good multicast time delay based on binary system molecule traffic model of a kind of effective parsing time delay, practicality and determines method.

Description

Multicast time delay determination method based on binary molecular communication model

Technical Field

The invention relates to biotechnology, nanotechnology and communication technology, in particular to a multicast topological structure network based on a binary molecular communication model, and particularly relates to a multicast time delay determination method.

Background

The rapid development of biotechnology and nanotechnology paves the way to the fabrication of nanometer-scale nanometer machines. Nanomachines are considered to be the most basic functional devices on the nanometer scale. The nanometer machine has better application prospect in the medical and industrial fields. However, the implementation of nanomachines in these fields is easily restricted by the characteristics of nanomachines themselves, such as their small size and unknown physical properties, which results in the uncontrollable and unstable application of nanomachines. These problems can be solved by coordination of nanoscale communication between nanomachines, forming networks between nanomachines called nanonetworks. The nano network can coordinate different nano machines to share information in a cooperative mode, so that complex tasks can be completed in a larger range.

The molecular communication is a novel communication mode among nanometer machines, and is a communication technology which takes biochemical molecules as information carriers, carries out mutual communication through the diffusion of the molecules in a biological environment and is used for the nanometer machines to form a distributed nanometer network. The carrier molecules of the information are referred to as information molecules. The basic communication process of molecular communication comprises five steps of information encoding, sending, transmitting, receiving and decoding. In a molecular communication system, information molecules that can be recognized and received by a receiving-side nanomachine are generated by a transmitting-side nanomachine of information, and the information is encoded based on physical or chemical characteristics of the information molecules. After the information molecules released by the sending-side nanomachines are transmitted to the receiving-side nanomachines through a fluid (liquid or gas) medium, the information is received by the receiving-side nanomachines and decoded in a specific manner.

Molecular communication has many good characteristics, for example, a specific type of information molecule can carry a large amount of information, so that a nanomachine can directly interact with various native components in a biological system, and has biocompatibility; in addition, molecular communication systems can also harvest sufficient energy from chemical reactions in the environment to support information transfer. Since molecular communication is not limited by the size and power consumption of transceivers, and is suitable for many specific application environments (e.g., in the human body), it is widely accepted by academia that molecular communication based on biological inspiration is one of the most feasible communication technologies for realizing nano-networks.

Disclosure of Invention

In order to overcome the defect that the existing multicast topological structure network cannot effectively determine the time delay, the invention provides the multicast time delay determination method based on the binary molecular communication model, which can effectively analyze the time delay and has good practicability.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a multicast time delay determining method based on a binary molecular communication model comprises the following steps:

firstly, analyzing the time delay of a single-link topological structure under the condition of link success

In a binary molecular communication model, different molecule types are transmitted to represent the transmission of bit 0 or 1, after a nanometer machine at a sending party releases molecules, the molecules move in a medium in a Brownian mode, and the probability density distribution function f (t) of the time t required by one molecule from the nanometer machine at the sending party to a nanometer machine at a receiving party with the distance d is as follows:

wherein D is the distance between the nanometer machine of the sender and the nanometer machine of the receiver, and D is the diffusion coefficient of the biological environment;

the cumulative distribution function f (t) corresponding to the probability density distribution function is:

for transmission between two nanomachines of a single link, the reliability of the link is defined as the probability that the receiving nanomachine receives at least one molecule, β_ijExpressed, calculated from the following formula:

β_ij＝1-(1-F(τ))^nN

wherein, N is the number of molecules released by the nano machine of the sender at each time slot (i.e. time slot), T is transmission time, T is divided into N time slots, i.e. T ═ N τ, N is the number of time slots, τ is the duration time of each time slot;

in single link transmission, the time delay is defined as the average time required for the receiving nanomachine to receive at least one molecule, using ETT_d]Represents; the transmission time required for a single link with the distance d is m tau, wherein m is the minimum value of inequality in the following formula, namely the time corresponding to the minimum time slot where at least one molecule is received

Wherein, β_ijTo the reliability of the corresponding link;

secondly, analyzing the reliability and time delay characteristics of the single-path topological structure under the condition of successful link

For a single-path topological structure, the reliability of a single path is the probability under the condition that each link is guaranteed to be reliable, and the calculation formula is as follows:

wherein r is_sThe reliability value of each link contained in the single path is collected;

for single path topology, the delay of single path is the sum of the delay needed by each link transmission, and E [ T ] is used_s]Expressed, the calculation formula is:

wherein, T_sFor each set of links included in a single path, E [ T ]_d]The time delay of each link contained in the single path;

thirdly, analyzing the time delay of the multi-path topological structure under the condition of successful link

For reliability of a multi-path topology, i.e. requiring at least one path to be reliable, the time delay is defined as the time required for the receiving nanomachines to receive at least one molecule, assuming that the molecule is sent from the same sending nanomachines over m paths s₁，s₂，…，s_mThe reliability of the multipath topology structure at the moment is achieved by reaching the same receiver nano machineExpressed, the calculation formula is:

wherein,is a path s_iReliability of (2);

time delay of multipath topology, usingExpressed, the calculation formula is:

wherein,is a path s_iA required time delay;

fourthly, analyzing the time delay of the multicast topological structure under the condition of successful link

The time delay from the same nanometer machine TN of the sender to different nanometer machines RN1, RN2, RN … and RN RNp of p receivers is respectively E [ T [ ]_RN1],E[T_RN2],...,E[T_RNp]，E[T_RN1],E[T_RN2],...,E[T_RNp]According to the calculation formula of the third step, the time delay under the multicast topology structure is calculated by using the time delay value of the T_Multicast]Expressed, the calculation formulas are respectively:

E[T_Multicast]＝max{E[T_RN1],E[T_RN2],...,E[T_RNp]}。

further, in the first step, β is used for reliability under a single link retransmission mechanism_ij' indicate, countThe calculation formula is as follows:

wherein f is_ijMaximum number of retransmissions for a single link, β_ijTo successfully transmit the reliability of a single link.

For the time delay under the single link retransmission mechanism, use E [ T ]_d]' expression, the calculation formula is:

wherein f is_ijMaximum number of retransmissions for a single link, E [ T ]_d]Time delay for successful transmission of a single link, T_ackIs the set timeout time.

Still further, in the second step, β is used for reliability under the single-path retransmission mechanism_s' expression, the calculation formula is:

wherein, β_ij' reliability under Single Link retransmission mechanism, r_s' is the set of reliability values for each link that a single path contains in the case of link transmission failure.

For the time delay under the single path retransmission mechanism, use E [ T ]_s]' expression, the calculation formula is:

wherein, T_s' A set of every link contained for a single path, E [ T ]_d]Is a single wayThe path contains the latency of each link.

The technical conception of the invention is as follows: the invention fully combines the characteristics of molecular communication such as biocompatibility, low speed, limited transmission range, higher loss rate and the like, and mainly develops a reliable and efficient data communication technology which can be used for a nano network and is based on the molecular communication.

In the binary molecular communication model, the transmission of a 0 or 1 is represented by the transmission of a different molecular type. In the molecular communication process, molecules released by a nanometer machine at a sending party are subjected to diffusion transmission in fluid, so that the molecules reach a nanometer machine at a receiving party with higher unreliability and are easy to suffer from longer time delay, and meanwhile, the topological structure of a molecular communication network is considered to have important influence on reliability and time delay. Therefore, how to reduce the transmission delay is a key problem that needs to be further developed and studied in depth on the premise that the information transmission of the binary molecular communication model is reliable in the multicast scene.

The invention has the following beneficial effects: 1. the method has the advantages that the time delay is effectively analyzed, the practicability is good, and the analytic expressions of the reliability and the time delay in different topological structures including single links, single paths, multiple paths and multicast scenes and the analytic expressions under a retransmission mechanism are analyzed based on a binary molecular communication model. Analyzing the variation trend of the reliability and the time delay along with the distance between the parameter nanometer machines, the diffusion coefficient of the biological environment, the number of molecules released by the nanometer machine of the sender in each time slot, the number of the time slots and the continuous time variation of each time slot through a mathematical expression; 2. a Stop-equality ARQ (Stop-wait Automatic Repeat reQuest) retransmission mechanism based on a binary molecular communication model improves the probability of receiving ACK molecules to the maximum limit by controlling the maximum retransmission times and determining the number of the molecules of the reply Acknowledgement (ACK) information of a receiving-party nanometer machine, simultaneously ensures the reliability of transmission, reduces the time cost and greatly reduces the complexity.

Drawings

Fig. 1 is a single link topology. Wherein, TN is the nanometer machine of the sender, RN is the nanometer machine of the receiver.

FIG. 2 is A topology of A single path consisting of three links TN-A, A-B, B-RN. TN, RN are respectively the sender nanometer machine and the receiver nanometer machine, A, B are the nanometer machine of the intermediate forwarding information molecule.

Fig. 3 is a multicast topology. TN is the sender nanomachines, RN1 and RN2 are the receiver nanomachines. TN-A1-B1-RN1, TN-A2-B2-RN1, TN-A3-B3-RN2 and TN-A4-B4-RN2 are four paths.

Fig. 4 is a schematic diagram of a design scheme for reliable and efficient multicast based on a binary molecular communication model.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1 to 4, a multicast delay determining method based on a binary molecular communication model includes the following steps:

in order to analyze the time delay situation of a binary molecular communication model under a multicast topological structure, a single link, a single path and a multi-path research scene are established.

Fig. 1 is a single link topology. Wherein, TN is the nanometer machine of the sender, RN is the nanometer machine of the receiver.

For transmission between two nanomachines of a single link, the reliability of the link is defined as the probability that the receiving nanomachine receives at least one molecule, β_ijExpressed, calculated using the following formula:

β_ij＝1-(1-F(τ))^nN

wherein, N is the number of molecules released by the nano machine at each time slot. Here, T is a transmission time, and is divided into n slots, that is, T ═ n τ, n is the number of time slots, and τ is the duration of each time slot.

For transmission between two nanomachines of a single link, the time delay is defined as the time required for the receiving nanomachine to receive at least one molecule, denoted by ETT_d]And (4) showing. The transmission time required for a single link with the distance d is m tau, wherein m is the minimum value of inequalities in the following formula, namely the time corresponding to the minimum time slot where at least one molecule is received.

Wherein, β_ijCorresponding to the reliability of the link.

FIG. 2 is A topology of A single path consisting of three links TN-A, A-B, B-RN. TN, RN are respectively the sender nanometer machine and the receiver nanometer machine, A, B are the nanometer machine of the intermediate forwarding information molecule.

For a single-path topological structure, the reliability of a single path is the probability under the condition that each link is guaranteed to be reliable, and the calculation formula is as follows:

wherein r is_sA set of reliability values for each link included for a single path.

For single path topology, the delay of single path is the sum of the delay needed by each link transmission, and E [ T ] is used_s]Expressed, the calculation formula is:

wherein, T_sFor each set of links included in a single path, E [ T ]_d]The delay of each link included for a single path.

For reliability of a multi-path topology, i.e. requiring at least one path to be reliable, the time delay is defined as the time required for the receiving nanomachines to receive at least one molecule, assuming that the molecule is sent from the same sending nanomachines over m paths s₁，s₂，…，s_mThe reliability of the multipath topology structure at the moment is achieved by reaching the same receiver nano machineExpressed, the calculation formula is:

wherein,is a path s_iReliability of (2);

time delay of multipath topology, usingExpressed, the calculation formula is:

wherein,is a path s_iA required time delay;

fig. 3 is a multicast topology. TN is the sender nanomachines, RN1 and RN2 are the receiver nanomachines.TN-A1-B1-RN1, TN-A2-B2-RN1, TN-A3-B3-RN2 and TN-A4-B4-RN2 are four paths, respectively denoted as s₁，s₂，s₃，s₄。

Assuming that the molecules are sent from the same sender nanomachines, two paths s are traversed₁，s₂To achieve the same receiver nanomachine RN1, the corresponding reliability is usedIndicating, time-delay usingExpressed, the calculation formulas are respectively:

wherein,is a path s_iThe reliability of (2).

Wherein,is a path s_iThe required time delay.

Transmitted from the same transmitting-side nanomachines through two paths s by the same calculation method₃，s₄The same receiving nano machine RN2 is reached, and the reliability of the multipath topology is usedExpressed, the calculation formula is:

then, the delay calculation formula based on the multicast model of fig. 3 is as follows

Fig. 4 is a design of a reliable and efficient multicast scheme based on a binary molecular communication model.

Through a retransmission mechanism of ARQ (Stop-wait Automatic Repeat reQuest), an analytic expression of reliability and time delay under the condition of the retransmission mechanism in a single link, a single path and multiple paths based on a binary molecular communication model is analyzed, and reliability and time delay characteristic analysis in a multicast scene is carried out on the basis. On the premise of ensuring the receiving reliability of the receiving part nanometer machine, the average time delay required by the molecule receiving is reduced, thereby ensuring the reliability and the high efficiency of the scheme.

The reliability calculation formula under the single link retransmission mechanism is as follows:

wherein f is_ijMaximum number of retransmissions for a single link, β_ijTo successfully transmit the reliability of a single link.

For the time delay under the single link retransmission mechanism, use E [ T ]_d]' expression, the calculation formula is:

wherein f is_ijMaximum number of retransmissions for a single link, E [ T ]_d]Time delay for successful transmission of a single link, T_ackIs the set timeout time.

For reliability under single path retransmission mechanism, β is used_s' expression, the calculation formula is:

wherein, β_ij' reliability under Single Link retransmission mechanism, r_s' is the set of reliability values for each link that a single path contains in the case of link transmission failure.

For the time delay under the single path retransmission mechanism, use E [ T ]_s]' expression, the calculation formula is:

wherein, T_s' A set of every link contained for a single path, E [ T ]_d]The delay of each link included for a single path.

Claims (3)

1. A multicast time delay determination method based on a binary molecular communication model is characterized in that: the multicast time delay determining method comprises the following steps:

firstly, analyzing the time delay of a single-link topological structure under the condition of link success

In a binary molecular communication model, different molecule types are transmitted to represent the transmission of bit 0 or 1, after a nanometer machine at a sending party releases molecules, the molecules move in a medium in a Brownian mode, and the probability density distribution function f (t) of the time t required by one molecule from the nanometer machine at the sending party to a nanometer machine at a receiving party with the distance d is as follows:

$f\left(t\right)=\frac{d}{\sqrt{4{\mathrm{\πDt}}^3}}{e}^{-\frac{d^2}{4Dt}},t>0$

wherein D is the distance between the nanometer machine of the sender and the nanometer machine of the receiver, and D is the diffusion coefficient of the biological environment;

the cumulative distribution function f (t) corresponding to the probability density distribution function is:

$F\left(t\right)=1-Erf\left(\frac{d}{2\sqrt{Dt}}\right),t>0$

for transmission between two nanomachines of a single link, the reliability of the link is defined as the probability that the receiving nanomachine receives at least one molecule, β_ijExpressed, calculated from the following formula:

β_ij＝1-(1-F(τ))^nN

n is the number of molecules released by a nano machine of a sender at each time slot, T is transmission time, and T is divided into N time slots, namely T is N tau, N is the number of the time slots, and tau is the duration time of each time slot;

in single link transmission, the time delay is defined as the average time required for the receiving nanomachine to receive at least one molecule, using ETT_d]Represents; the transmission time required for a single link with the distance d is m tau, wherein m is the minimum value of inequality in the following formula, namely the time corresponding to the minimum time slot where at least one molecule is received

$E\[T_d\]=min\{m\mathrm{\τ}:\frac{1}{{\mathrm{\β}}_{ij}}\underset{k=1}{\overset{m}{\Σ}}{(1-F(\mathrm{\τ}\left)\right)}^{N(k-1)}(1-{\left(1-F\left(\mathrm{\τ}\right)\right)}^N)\≥0.5,1\≤m\≤n\}$

Wherein, β_ijTo the reliability of the corresponding link;

secondly, analyzing the time delay of the single-path topological structure under the condition of successful link

For a single-path topological structure, the reliability of a single path is the probability under the condition that each link is guaranteed to be reliable, and the calculation formula is as follows:

${\mathrm{\β}}_s=\underset{{\mathrm{\β}}_{ij}\∈r_s}{\Π}{\mathrm{\β}}_{ij}$

wherein r is_sThe reliability value of each link contained in the single path is collected;

for single path topology, the delay of single path is the sum of the delay needed by each link transmission, and E [ T ] is used_s]Expressed, the calculation formula is:

$E\[T_s\]=\underset{E\[T_d\]\∈T_s}{\Σ}E\[T_d\]$

wherein, T_sFor each set of links included in a single path, E [ T ]_d]The time delay of each link contained in the single path;

thirdly, analyzing the time delay of the multi-path topological structure under the condition of successful link

For reliability of a multi-path topology, i.e. requiring at least one path to be reliable, the time delay is defined as the time required for the receiving nanomachines to receive at least one molecule, assuming that the molecule is sent from the same sending nanomachines over m paths s₁，s₂，…，s_mThe reliability of the multipath topology structure at the moment is achieved by reaching the same receiver nano machineExpressed, the calculation formula is:

${\mathrm{\β}}_{s_{1,m}}=1-\underset{s_i\∈\{s_1,s_2,\mathrm{...},s_m\}}{\mathrm{\Π}}(1-{\mathrm{\β}}_{s_i})$

wherein,is a path s_iReliability of (2);

time delay of multipath topology, usingExpressed, the calculation formula is:

$E\[T_{s_{1,m}}\]=\frac{1}{\underset{s_i\∈\{s_1,s_2,\mathrm{...},s_m\}}{\Σ}{\mathrm{\β}}_{s_i}}\underset{s_i\∈\{s_1,s_2,\mathrm{...},s_m\}}{\Σ}{\mathrm{\β}}_{s_i}E\[T_{s_i}\]$

wherein,is a path s_iA required time delay;

fourthly, analyzing the time delay of the multicast topological structure under the condition of successful link

The time delay from the same nanometer machine TN of the sender to different nanometer machines RN1, RN2, RN … and RN RNp of p receivers is respectively E [ T [ ]_RN1],E[T_RN2],...,E[T_RNp]，E[T_RN1],E[T_RN2],...,E[T_RNp]According to the calculation formula of the third step, the time delay under the multicast topology structure is calculated by using the time delay value of the T_Multicast]Expressed, the calculation formulas are respectively:

E[T_Multicast]＝max{E[T_RN1],E[T_RN2],...,E[T_RNp]}。

2. the binary molecular communication model-based multicast delay determination method as claimed in claim 1, wherein in the first step, β is used for reliability under single link retransmission mechanism_ij' expression, the calculation formula is:

${{\mathrm{\β}}_{ij}}^{\′}={\mathrm{\β}}_{ij}+(1-{\mathrm{\β}}_{ij}){\mathrm{\β}}_{ij}+{(1-{\mathrm{\β}}_{ij})}^2{\mathrm{\β}}_{ij}+\mathrm{...}+{(1-{\mathrm{\β}}_{ij})}^{f_{ij}}{\mathrm{\β}}_{ij}=\underset{m=0}{\overset{f_{ij}}{\Σ}}{(1-{\mathrm{\β}}_{ij})}^m{\mathrm{\β}}_{ij}$

wherein f is_ijMaximum number of retransmissions for a single link, β_ijFor successful transmission of a single linkReliability of (2);

for the time delay under the single link retransmission mechanism, use E [ T ]_d]' expression, the calculation formula is:

$E{\[T_d\]}^{\′}=2{{\mathrm{\β}}_{ij}}^{2}E\[T_d\]+\underset{m=0}{\overset{f_{ij}}{\Σ}}m{(1-{{\mathrm{\β}}_{ij}}^2)}^m{T}_{ack}$

wherein f is_ijMaximum number of retransmissions for a single link, E [ T ]_d]Time delay for successful transmission of a single link, T_ackIs the set timeout time.

3. The binary molecular communication model-based multicast delay determination method as claimed in claim 2, wherein in said second step, β is used for reliability under single-path retransmission mechanism_sIn the' expression,the calculation formula is as follows:

${{\mathrm{\β}}_s}^{\′}=\underset{{{\mathrm{\β}}_{ij}}^{\′}\∈{r_s}^{\′}}{\Π}{{\mathrm{\β}}_{ij}}^{\′}$

wherein, β_ij' reliability under Single Link retransmission mechanism, r_s' is a set of reliability values for each link that the single path contains in the case of link transmission failure;

for the time delay under the single path retransmission mechanism, use E [ T ]_s]' expression, the calculation formula is:

$E{\[T_s\]}^{\′}=\underset{E\[T_d\]\∈{T_s}^{\′}}{\Σ}E\[T_d\]$

wherein, T_s' A set of every link contained for a single path, E [ T ]_d]The delay of each link included for a single path.