CN102316550B - Wireless terminal dynamic access method - Google Patents

Abstract

The invention discloses a wireless terminal dynamic access method, which comprises the following steps that: the access probability threshold and the maximum delay time of a wireless terminal access network are set, a mobile terminal dynamically find access points which have the fewest hops from the wireless terminal and meet the access condition in the maximum delay time, and when the access points are found, the connection from the wireless terminal to the access point is built, so the shortest path can be found in the wireless terminal moving process to be accessed into a network, and the link expense is small. When the access points meeting the condition can not be found in the maximum delay time, the connection from the wireless terminal to the access point is built at the moment of the maximum delay time, because the access points conforming to the condition are not found in the whole maximum delay access time, the connection can not be built in the whole maximum delay time, and the network blockage of the network can be avoided in a relatively long time.

Description

A kind of Wireless terminal dynamic access method

Technical field

The invention belongs to mobile communication technology field, be specifically related to set up in multi-hop mode the method that wireless terminal connects to communications infrastructure access point.

Background technology

Most of wireless network traffic application, particularly Internet of Things application, requires first access communications infrastructure of mobile terminal device, and access point, could carry out related service application.For example, in Internet of Things, base station is used as access point, and internet-of-things terminal will be linked into Internet of Things, must set up terminal to the route of Internet of Things base station.Internet-of-things terminal multi-hop dynamic access is exactly in fact when terminal can not find the direct route to base station, can between foundation, receive the route of base station using other terminal as intermediate node, thus access Internet of Things.

At document " Yicong Tian; Rui hou.An improved AOMDV Routing Protocol for Internet of Things.International Conference on Computational Intelligence and Software Engineering2010; pp.1-4 ", a kind of route cut-in method has been proposed, its main thought is: each terminal in Internet of Things is all reciprocity, has communication and these two kinds of functions of route concurrently.The communication of Internet of Things needs the participation of the Internet, and terminal need to be linked into the Internet and could communicate by letter, and the terminal that need to communicate only need to, using the terminal that is directly connected to the Internet as destination node, be established to the route of this destination node.This route cut-in method need to be set up the Internet connection table and routing table, and the content of networking connection table the inside comprises destination node numbering, destination node IP address, life cycle and jumping figure, and each terminal of Internet of Things needs to safeguard two tables.Utilize the method, terminal maintenance networking connection table and routing table separately will expend many resources, and expense is larger.

Summary of the invention

The object of invention is that the expense that existing wireless terminal route cut-in method exists is large, the problem of consumes resources in order to solve, and has proposed a kind of Wireless terminal dynamic access method.

Technical scheme of the present invention is: a kind of Wireless terminal dynamic access method, specifically comprises the steps:

Step 1: the access probability threshold value P that determines wireless terminal ₀with maximum delay Δ turn-on time T, wherein, access probability represents the probability connecting between target wireless terminals and access point;

Step 2: described wireless terminal enters network, in search neighbors terminal, whether there is access point, if had, this wireless terminal is direct and access point is set up route, otherwise, described wireless terminal is by selecting the neighbors terminal of described wireless terminal to set up route with access point, select the detailed process of the neighbors terminal of described wireless terminal to be: to find out in neighbors terminal to a minimum neighbors terminal of access point jumping figure, suppose that the neighbors terminal found out is n-1 to the jumping figure of described access point, described wireless terminal is n to the minimum hop count of described access point,

Calculate access probability P _n-1and P (t) _n(t), P _n(t) represent the probability that described wireless terminal connects between the t moment and described access point, P _n-1(t) represent the probability that described neighbors terminal connects between the t moment and described access point; As access probability P _n-1and P (t) _n(t) meet P _n-1(t) <P ₀and P _n(t)>=P ₀time, set up described wireless terminal to the connection of described access point, otherwise, wireless terminal is ceaselessly searched in mobile process, the time of search is restricted to maximum delay Δ turn-on time T, if in the process of search, if be met the access point of condition, set up being connected of described wireless terminal and access point; If can not find, equal qualified access point and search time maximum delay Δ turn-on time T, also will set up being connected of described wireless terminal and described access point.

Further, calculate access probability P _n-1and P (t) _n(t) detailed process is as follows:

$P_n\left(t\right)=\left\{\begin{array}{c}{1-e}^{-{\mathrm{\&lambda;}}_1\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;},n=1\\ P_{n-1}\left(t\right)+\&lsqb;1-P_{n-1}\left(t\right)\&rsqb;P_1\left(t\right){(1-e^{-{\mathrm{\&lambda;}}_2\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;})}^{n-1},n\&GreaterEqual;2\end{array}\right.$

Wherein, λ ₁it is Parameter for Poisson Distribution when access point is obeyed Poisson distribution in network; λ ₂parameter for Poisson Distribution while being the Poisson distribution of wireless terminal obedience; R is the communication radius of a jumping scope; V is the translational speed of wireless terminal.

Beneficial effect of the present invention: method of the present invention is by access probability threshold values and the maximum delay time of setting wireless accessing terminal to network, in maximum delay time, mobile terminal is dynamically found minimum apart from this wireless terminal jumping figure, and meet the access point of access conditions, if can find, set up described wireless terminal to the connection of access point, find the shortest path access network in the process that so just can move at wireless terminal, link overhead is smaller; If can not find the access point satisfying condition in maximum delay time, at maximum delay time, that sets up described wireless terminal constantly to the connection of access point, owing to not finding qualified access point in turn-on time at whole maximum delay, in whole maximum delay time, can not connect like this, make network avoid network congestion within the long period of time that compares.

Accompanying drawing explanation

Fig. 1 is the topological structure schematic diagram of network access by wireless terminal.

Fig. 2 is that wireless terminal accesses the schematic diagram of Internet of Things in mobile process.

Fig. 3 is Wireless terminal dynamic access method schematic flow sheet.

Embodiment

Below in conjunction with accompanying drawing and concrete example, the present invention is further illustrated.

Shown in the topological structure schematic diagram 1 of network access by wireless terminal.The access point and the wireless terminal that exist in one network quantity not wait, what the present invention is directed to is how new wireless terminal connects with access point while entering this network.

The Internet of Things of take is specifically described as example, and as shown in Figure 2, access point is specially base station.The base station distribution of Internet of Things is that average mark is furnished with 5 base stations in the region of 10000 square metres, i.e. the Parameter for Poisson Distribution λ of base station in Internet of Things ₁for 0.00005(/m ²), in the region of 100 square metres, average mark is furnished with 1 wireless terminal, i.e. terminal Parameter for Poisson Distribution λ ₂for 0.01(/m ²).The movement speed v of target wireless terminals A is 60(m/min), a communication radius r who jumps scope is 100m, idiographic flow schematic diagram is as shown in Figure 3.

Step 1: determine access probability threshold value P ₀with maximum delay Δ turn-on time T, access probability represents the probability connecting between target wireless terminals and access point.

Maximum delay Δ turn-on time T is taken as the business hours conventionally, and in the present embodiment, Δ T is taken as 5min.P ₀at this, can regard a parameter as, by empirical value, get P ₀=0.5.At this, get P ₀=0.5, there is certain reasonability: when access probability when all very large, is far longer than P with interior at whole maximum delay time Δ T ₀can not in maximum delay time Δ T, find the access point satisfying condition so, at that moment of maximum delay time t=Δ T, set up described mobile terminal to the connection of access point, owing to not finding qualified access point in whole maximum delay time, in whole maximum delay time, can not connect like this, can make like this network avoid network congestion within the long period of time that compares.Otherwise, P in maximum delay time Δ T _n≤ P ₀, can find the access point satisfying condition, set up described mobile terminal to the connection of access point, in the process that so just can move at wireless terminal, find the shortest path access of radio network, link overhead is smaller, so P ₀be equivalent to a median, be therefore taken as 0.5.

Step 2: when target wireless terminals A enters Internet of Things, in the neighbors terminal of search target wireless terminals A, whether there is base station, in neighbors terminal due to A, there is no base station, so find in neighbors terminal to the minimum abutment points terminal of base station jumping figure, the neighbors terminal to base station jumping figure minimum of terminal A be 2.

Calculate access probability P _n-1and P (t) _n(t):

In the present embodiment, access probability P _n(t) the following a kind of account form of the concrete employing of calculating, concrete derivation is as follows: from Poisson distribution character,

wherein to be illustrated in the parameter of the Poisson distribution of base station be λ to P (X=k) ₁prerequisite under, the regional extent that is s at the area of take centered by mobile terminal contains the probability of k base station, wherein s=π r ²+ 2rv (Δ T-t), within the scope of a jumping, can set up so wireless terminal and to the connection of base station, just be equivalent to parameter k>=1 in the Poisson distribution of base station, by the method for asking complementary events probability of happening, obtain setting up within the scope of a jumping mobile terminal and to the access probability formula of the foundation of access point be: $P_1\left(t\right)=1-e^{-{\mathrm{\&lambda;}}_1({\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t))}.$

Use P ₂' (t) represent that terminal equipment A can only receive the probability of the route of base station in moving process between double bounce is with interior can foundation; Use P ₁' (t) represent that terminal equipment A, in moving process, does not have base station in its neighbors terminal, but the probability of other terminal equipment had.

$P_1\left(t\right)=1-e^{-{\mathrm{\&lambda;}}_1({\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t))}$

P ₂(t)=P ₁(t)+P ₂′(t)

${{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000097360190000021.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}^{\&prime;}\left(t\right)=(1-P_1\left(t\right))(1-e^{{-\mathrm{\&lambda;}}_2({\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)})$

P ₂′(t)=P ₁(t)P ₁′(t)

P ₂(t)=P ₁(t)+P ₂′(t)

In like manner can obtain:

$P_n\left(t\right)=P_{n-1}\left(t\right)+\&lsqb;1-P_{n-1}\left(t\right)\&rsqb;P_1\left(t\right){(1-e^{-{\mathrm{\&lambda;}}_2\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;})}^{n-1},n\&GreaterEqual;2$

So computing formula is:

$P_n\left(t\right)=\left\{\begin{array}{c}{1-e}^{-{\mathrm{\&lambda;}}_1\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;},n=1\\ P_{n-1}\left(t\right)+\&lsqb;1-P_{n-1}\left(t\right)\&rsqb;P_1\left(t\right){(1-e^{-{\mathrm{\&lambda;}}_2\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;})}^{n-1},n\&GreaterEqual;2\end{array}\right.$

Correspond in this example,

$P_1\left(t\right)=1-e^{-{\mathrm{\&lambda;}}_1({\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t))}$

$P_2\left(t\right)=P_{n-1}\left(t\right)+\&lsqb;1-P_{n-1}\left(t\right)\&rsqb;P_1\left(t\right)(1-e^{-{\mathrm{\&lambda;}}_2\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;})$

T=0 when wireless terminal A has just entered Internet of Things, by Δ T=5min, λ ₁=0.00005(/m ²), λ ₂=0.01(/m ²), r=100m, v=60(m/min), π=3.14 substitution formula calculates, P ₁(t)=0.9889, P ₂(t)=0.9999, by P ₂and P (t) ₀(t) big or small, P ₂(t) >P ₀(t), the P that do not satisfy condition _n-1(t) <P ₀and P _n(t)>=P ₀.Now, wireless terminal A does not connect with base station.Wireless terminal A continues search neighbors terminal in mobile process, when due in t=5min, by Δ T=5min, λ ₁=0.00005(/m ²), λ ₂=0.01(/m ²), r=100m, v=60(m/min), π=3.14 substitution formula calculates, P ₁(t)=0.7920, P ₂(t)=0.9567, P does not satisfy condition _n-1(t) <P ₀and P _n(t)>=P ₀, but because reached turn-on time search time, so now wireless terminal A must connect with base station, wherein, n=2, can set up the route that wireless terminal is 2 to the transfer jumping figure of base station.

Those of ordinary skill in the art will appreciate that, embodiment described here is in order to help reader understanding's principle of the present invention, should be understood to that protection scope of the present invention is not limited to such special statement and embodiment.Those of ordinary skill in the art can make various other various concrete distortion and combinations that do not depart from essence of the present invention according to these technology enlightenments disclosed by the invention, and these distortion and combination are still in protection scope of the present invention.

Claims (2)

1. a Wireless terminal dynamic access method, specifically comprises the steps:

Step 1: the access probability threshold value P that determines wireless terminal ₀with maximum delay time Δ T, wherein, access probability represents the probability connecting between target wireless terminals and access point;

Step 2: described wireless terminal enters network, in search neighbors terminal, whether there is access point, if had, this wireless terminal is direct and access point is set up route, otherwise, described wireless terminal is by selecting the neighbors terminal of described wireless terminal to set up route with access point, select the detailed process of the neighbors terminal of described wireless terminal to be: to find out in neighbors terminal to a minimum neighbors terminal of access point jumping figure, suppose that the neighbors terminal found out is n-1 to the jumping figure of described access point, described wireless terminal is n to the minimum hop count of described access point,

Calculate access probability P _n-1and P (t) _n(t), P _n(t) represent the probability that described wireless terminal connects between the t moment and described access point, P _n-1(t) represent the probability that described neighbors terminal connects between the t moment and described access point; As access probability P _n-1and P (t) _n(t) meet P _n-1(t) <P ₀and P _n(t)>=P ₀time, set up described wireless terminal to the connection of described access point, otherwise, wireless terminal is ceaselessly searched in mobile process, the time of search is restricted to maximum delay Δ turn-on time T, if in the process of search, if be met the access point of condition, set up being connected of described wireless terminal and access point; If can not find, equal qualified access point and search time maximum delay Δ turn-on time T, also will set up being connected of described wireless terminal and described access point;

Described calculating access probability P _n-1and P (t) _n(t) detailed process is as follows:

$P_n\left(t\right)=\left\{\begin{array}{c}{1-e}^{-{\mathrm{\&lambda;}}_1\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;},n=1\\ P_{n-1}\left(t\right)+\&lsqb;1-P_{n-1}\left(t\right)\&rsqb;P_1\left(t\right){(1-e^{-{\mathrm{\&lambda;}}_2\&lsqb;{\mathrm{\&pi;r}}^2+2\mathrm{rv}(\mathrm{\&Delta;T}-t)\&rsqb;})}^{n-1},n\&GreaterEqual;2\end{array}\right.$

Wherein, λ ₁it is Parameter for Poisson Distribution when access point is obeyed Poisson distribution in network; λ ₂parameter for Poisson Distribution while being the Poisson distribution of wireless terminal obedience; R is the communication radius of a jumping scope; V is the translational speed of wireless terminal.

2. Wireless terminal dynamic access method according to claim 1, is characterized in that, the access probability threshold value P described in step 1 ₀be 0.5.

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