CN103596232A - Vertical switching method and vertical switching device - Google Patents

Abstract

The invention discloses a vertical switching method. Information of each access network and a priority mode selected by a user which can be accessed at present by a mobile terminal on a motion carrier are acquired; under the priority mode selected by the user, switching probabilities of the mobile terminal are determined when the mobile terminal is switched to each of the access networks, and the mobile terminal is switched to the other access networks when the switching probability of the present access network is smaller than switching probabilities of other access networks. The invention further discloses a vertical switching device. Through the technical scheme, not only can preference of the user be met, but also switching quality can further be guaranteed, and unnecessary switching is reduced.

Description

Vertical handoff method and device

Technical field

The Vertical Handoff Technology that the present invention relates to car networking field, relates in particular to a kind of vertical handoff method and device.

Background technology

Car networking is vehicle Internet of Things, is the focus of accompaniment networking technology and application demonstration research thereof.Along with the development of car networking, each network relating in car networking is tending towards merging.By the fusion between heterogeneous network, each network can farthest be brought into play the advantage of self, thereby meets the demand of user to network.

At present, the wireless access technology relating in car networking mainly contains: 1) (the Wireless Access in the Vehicular Environment of the wireless access under vehicle environment, WAVE), WAVE is mainly used in in-vehicle wireless communication, serve as Dedicated Short Range Communications, (Dedicated Short Range Communications, DSRC) or towards the basis of vehicle mounted communication, can support more advanced focus switching, mobile environment, fail safe and authentication, transmission range can reach 1000 meters; Because WAVE belongs to WLAN (Wireless Local Area Networks, WLAN) family, of the present inventionly below will represent WAVE network with wlan network; 2) worldwide interoperability for microwave access (Worldwide Interoperability for Microwave Access, WiMAX), be a kind of emerging wireless access wide band technology, its message transmission rate is high, coverage distance 50km, the translational speed of support node 160km/h; 3) 3G (Third Generation) Moblie Cellular Networks technology (3rd-Generation, 3G Cellular), it has wide coverage, can realize seamless switching, support the advantage of the node of high-speed mobile, but transmission rate is limited.When Vehicle Driving Cycle is during at urban environment, vehicle generally accesses wlan network, wlan network is mainly used in (Vehicle-to-Vehicle between vehicle and vehicle, V2V) (Vehicle-to-Roadside and between vehicle and base station, roadside, V2R) communication, wireless communication technology usually used as car self-organization network under urban environment (Vehicular Adhoc Network, VANET); When Vehicle Driving Cycle is during in suburb, vehicle generally accesses WiMAX or 3GCellular network; And when Vehicle Driving Cycle is during in remote districts, vehicle generally accesses 3G Cellular network.

Car networking has its uniqueness, is mainly manifested in: one, car networking belongs to heterogeneous wireless network, and two, the vehicle termination self in car networking has mobile characteristic.Vertical switching refers to the switching between different type network, to adapt to the demand of different business under varying environment.Under heterogeneous wireless network environment, the terminal use of high-speed mobile needs access network whenever and wherever possible, yet, in vertical handover procedure, because terminal use is difficult to be protected to network connect hours and state after the preference difference of network selection and switching, cannot meet user's switching demand.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of vertical handoff method and device, not only can meet the preference of user to network, and can guarantee quality of handoff, reduces unnecessary switching.

For achieving the above object, technical scheme of the present invention is achieved in that

The invention provides a kind of vertical handoff method, described method comprises: obtain the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects; Under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.

In such scheme, described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority, wherein, described business adapts to mode of priority and comprises and contain session service mode of priority and do not contain session service mode of priority.

In such scheme, when the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th; Wherein, determine in the following manner the switching probability P under the movement tendency of described motion carrier _h1: P _h1=P (Δ D _n< 0); Wherein,

Δ D _nchange for the distance accumulation of access network in setting-up time section and, K ₁for transmitted power, K ₂for the path loss factor, the computing function that u (x) is interference signal intensity, u (x) is 0 for obeying average, variance is σ ₂gaussian random distribution function, wherein, x is stochastic variable; M receives the number of times that intensity level is sampled, the received signal strength that RSS (i) is current sampling point, the received signal strength that RSS (i-1) is last sampled point for dock signal in described setting-up time section, i is current sampling number, i=1,2, ..., M; When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh; Wherein, determine in the following manner the switching probability P under described peak transfer rate C _h2:

wherein,

for the minimum transmission rate that can support that mobile terminal current business is required, described peak transfer rate wherein, W is frequency bandwidth,

for signal to noise ratio, the interference signal intensity that I (d) receives while being the distance d between motion carrier and Network Access Point; When the mode of priority that described user selects is network charges mode of priority, the normalization numerical value α of network charges of usining switches to the switching probability P of described access network as described mobile terminal under network charges mode of priority _ch; The mode of priority that described user selects is when containing session service mode of priority, and normalization numerical value β corresponding to the network priority that contains session service of usining is as containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _sh; The mode of priority that described user selects when not containing session service mode of priority, is usingd and is not contained normalization numerical value γ that the network priority of session service is corresponding as not containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _eh.

In such scheme, the mode of priority that described user selects is network while continuing mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₁probability P (h ₃h ₄h ₅h ₁); When the mode of priority that described user selects is network bandwidth mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₂probability P (h ₃h ₄h ₅h ₂); When the mode of priority that described user selects is network charges mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value α of network charges; The mode of priority that described user selects is when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value β of the network priority that contains session service; The mode of priority that described user selects is not when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value γ of the network priority that does not contain session service; Wherein, h ₁for there is access network at setting-up time section T _nin distance accumulation change and be less than 0 event, h ₂for there is peak transfer rate, be greater than the event of the minimum transmission rate that can support that mobile terminal current business is required, h ₃for there is received signal strength, be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, h ₄for there is the error rate, be less than the event of the maximum bit error rate that meets mobile terminal service demand, h ₅for there is not the event of blocking in network.

In such scheme, described method also comprises: determine that in the following manner event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅), determine described mobile terminal generation event h ₃probability P _h3=P (h ₃); Determine that described mobile terminal is at the event of generation h ₃basis on generation event h ₄probability P (h ₄| h ₃); Determine that event h occurs described mobile terminal at the same time ₃and h ₄basis on generation event h ₅probability P (h ₅| h ₃h ₄); Determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅)=P (h ₃) * P (h ₄| h ₃) * P (h ₃| h ₄h ₅).

The present invention also provides a kind of vertical switching device shifter, described device comprises: acquiring unit and switch unit, wherein, described acquiring unit, for obtaining the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects; Described switch unit, under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.

In such scheme, described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority, and wherein said business adaptation mode of priority comprises and contains session service mode of priority and do not contain session service mode of priority.

In such scheme, when the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th; Wherein, determine in the following manner the switching probability P under the movement tendency of described motion carrier _h1: P _h1=P (Δ D _n< 0); Wherein, ${\mathrm{\&Delta;D}}_n=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}[{10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}\left(i\right)}{K_2}}-{10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}(i-1)}{K_2}}],$ Δ D _nchange for the distance accumulation of access network in setting-up time section and, K ₁for transmitted power, K ₂for the path loss factor, the computing function that u (x) is interference signal intensity, u (x) is 0 for obeying average, variance is σ ₂gaussian random distribution function, wherein, x is stochastic variable; M receives the number of times that intensity level is sampled, the received signal strength that RSS (i) is current sampling point, the received signal strength that RSS (i-1) is last sampled point for dock signal in described setting-up time section, i is current sampling number, i=1,2, ..., M; When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh; Wherein, determine in the following manner the switching probability P under described peak transfer rate C _h2:

wherein,

for the minimum transmission rate that can support that mobile terminal current business is required, described peak transfer rate wherein, W is frequency bandwidth,

for signal to noise ratio, the interference signal intensity that I (d) receives while being the distance d between motion carrier and Network Access Point; When the mode of priority that described user selects is network charges mode of priority, the normalization numerical value α of network charges of usining switches to the switching probability P of described access network as described mobile terminal under network charges mode of priority _ch; The mode of priority that described user selects is when containing session service mode of priority, and normalization numerical value β corresponding to the network priority that contains session service of usining is as containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _sh; The mode of priority that described user selects when not containing session service mode of priority, is usingd and is not contained normalization numerical value γ that the network priority of session service is corresponding as not containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _eh.

In such scheme, the mode of priority that described user selects is network while continuing mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₁probability P (h ₃h ₄h ₅h ₁); When the mode of priority that described user selects is network bandwidth mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₂probability P (h ₃h ₄h ₅h ₂); When the mode of priority that described user selects is network charges mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value α of network charges; The mode of priority that described user selects is when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value β of the network priority that contains session service; The mode of priority that described user selects is not when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value γ of the network priority that does not contain session service; Wherein, h ₁for there is network at setting-up time section T _nin distance accumulation change and be less than 0 event, h ₂for there is peak transfer rate, be greater than the event of the minimum transmission rate that can support that mobile terminal current business is required, h ₃for there is received signal strength, be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, h ₄for there is the error rate, be less than the event of the maximum bit error rate that meets mobile terminal service demand, h ₅for there is not the event of blocking in network.

In such scheme, described device determines that event h occurs described mobile terminal simultaneously in the following manner ₃, h ₄and h ₅probability P (h ₃h ₄h ₅): determine described mobile terminal generation event h ₃probability P _h3=P (h ₃); Determine that described mobile terminal is at the event of generation h ₃basis on generation event h ₄probability P (h ₄| h ₃); Determine that event h occurs described mobile terminal at the same time ₃and h ₄basis on generation event h ₅probability P (h ₅| h ₃h ₄); Determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅)=P (h ₃) * P (h ₄| h ₃) * P (h ₅| h ₃h ₄).

Vertical handoff method provided by the invention and device, first obtain the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects; Then, under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.So, the present invention, for the effective access network of motion carrier provides assurance, not only can meet the preference of user to network, and can guarantee quality of handoff, reduces unnecessary switching.

Further, the present invention sets up decision tree with network attribute and mode of priority, under the mode of priority of selecting, carries out trade-off decision user, and so, the objective network switching is optimal network, has embodied the real needs of terminal use to network.

Accompanying drawing explanation

Fig. 1 is the realization flow schematic diagram of vertical handoff method of the present invention;

Fig. 2 is the motion carrier of vertical handoff method of the present invention and the motion model schematic diagram between Network Access Point;

Fig. 3 is the structural representation of certainly selecting decision tree of vertical handoff method embodiment mono-of the present invention;

Fig. 4 is the structural representation of certainly selecting decision tree of vertical handoff method embodiment bis-of the present invention;

Fig. 5 is the composition structural representation of the vertical switching device shifter of the present invention.

Embodiment

Main thought of the present invention is: first obtain the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects; Then, under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other; Like this, not only can meet the preference of user to network, and can guarantee quality of handoff, reduce unnecessary switching.

Here, described motion carrier mainly refers to vehicle, and described access network comprises wlan network, WiMAX internet and 3G honeycomb (Cellular) network.

Here, described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority, wherein, the type of service that described business adaptation mode of priority comprises according to described mobile terminal is divided into and contains session service mode of priority and do not contain session service mode of priority.

Accordingly, when the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th;

When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate (Data Transfer Rate, DTR) _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh;

When the mode of priority that described user selects is network charges mode of priority, the normalization numerical value α of network charges of usining switches to the switching probability P of described access network as described mobile terminal under network charges mode of priority _ch;

The mode of priority that described user selects is when containing session service mode of priority, and normalization numerical value β corresponding to the network priority that contains session service of usining is as containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _sh;

The mode of priority that described user selects when not containing session service mode of priority, is usingd and is not contained normalization numerical value γ that the network priority of session service is corresponding as not containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _eh.

Below in conjunction with the drawings and specific embodiments, the technical solution of the present invention is further elaborated.

Fig. 1 is the realization flow schematic diagram of vertical handoff method of the present invention, and as shown in Figure 1, vertical handoff method of the present invention comprises the following steps:

Step 101, obtains the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects;

Here, described access network comprises wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃.

At present, third generation partner program (The3rd Generation Partnership Project, 3GPP) having defined altogether four class Business Stream grades, is respectively conversation class (Conversational Service), Streaming Media class (Streaming Service), interactive class (Interactive Service) and background class (Background Service).Wherein, session service is the real time business of a quasi-representative, requires end-to-end delay and shake little, and this type of business has voice conversation, multimedia conferencing and IP phone etc.; The transfer of data of Streaming Media class business has one-way, is also real time business, and looser to postponing requirement, this type of business has video request program, internet video live broadcasting etc.; Interaction service adopts request-response modes, to postponing, does not almost require, and this type of business is mainly represented as web browsing; Background class traffic is conventionally to not restriction of transmission delay, and typical services is as E-mail or backstage FTP download etc.This four classes business has different requirements according to the feature of self to network: what session service stressed is quality of the conversation, its real-time characteristic is as far as possible little on the impact of session while needing network to switch, 3G Cellular technology can guarantee the quality of session well, when so mobile terminal service comprises session service, wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃priority be N ₃> N ₂> N ₁; Streaming Media class business datum amount is larger, needs network to have enough Bandwidth guaranteeds and cheap data cost, wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃network priority be N ₁> N ₂> N ₃; Interaction service and background class traffic require similarly to network, and less demanding to postponing, data volume is also little, so corresponding priority is N ₁> N ₂> N ₃.In the ordinary course of things, the business on mobile terminal may comprise one or more business, and this need to consider decision-making in conjunction with user's preference.

The individual preference of selecting for network according to mobile terminal, the present invention first determines the following at user option mode of priority of several classes, and described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority.Wherein,

Described network continues mode of priority, is that user terminal is wished certain network of access of long period and avoided occurring too much switching, guarantees that the lasting time of the network of access is large as far as possible.By described network, continued the definition of mode of priority, therefore at network, continue under mode of priority, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of a certain described access network _th.

Described network bandwidth mode of priority is that user terminal wishes that accessed network has higher transmission rate.By the definition of described network bandwidth mode of priority, therefore under network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of a certain described access network _bh.

Described network charges mode of priority, is because the required communication cost of each network differs, and mobile terminal is wished the cheaper network of network service cost of access;

Described business adapts to mode of priority, be mobile terminal under current business, wish the requirement of the network As soon as possible Promising Policy terminal traffic of access; Described business adaptation mode of priority comprises again and contains session service mode of priority and do not contain session service mode of priority.

Under described network charges mode of priority and business adaptation mode of priority, not having corresponding switching probability distributes, here, can network charges and service priority be normalized by the method for normalization numerical value, the preference degree of normalization numeric representation user to network, normalized value shows that more greatly user is higher for this network preference degree.

Step 102, under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.

Below in conjunction with embodiment mono-and embodiment bis-, the concrete enforcement of abovementioned steps 102 is further elaborated.

Embodiment mono-:

When the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th;

Concrete, the movement tendency of described motion carrier refer to mobile terminal on motion carrier away from or approach the state of Network Access Point.The movement tendency of described motion carrier is to trigger the vertical important parameter switching, and this is to maintain time of network and switching times etc. after network insertion because it can have influence on.The movement tendency of motion carrier has front tropism, and can think within a short period of time, and the movement locus of motion carrier approaches straight line.Fig. 2 is the motion carrier of vertical handoff method of the present invention and the motion model schematic diagram between Network Access Point, as shown in Figure 2, when motion carrier moves in position A, the distance d between motion carrier and the access point C of network 3G Cellular ₁be less than the distance d between the access point D of itself and network WiMAX ₂.When motion carrier moves to after the B of position, along with the continuation of motion, the distance d between motion carrier and the access point C of network 3G Cellular ₁be greater than gradually the distance d between the access point D of itself and network WiMAX ₂, according to the changing method based on distance, need again to carry out network switching, thereby produced ping-pong.And the present invention changes by distance accumulation and method determine the movement tendency of motion carrier, then determine that under described movement tendency mobile terminal switches to the switching probability of current each network that can access.

In general, the movement tendency of motion carrier can be determined according to the variation of the distance d between motion carrier and Network Access Point, determine distance between current motion carrier and Network Access Point and the difference of the distance between previous moment motion carrier and this Network Access Point, if difference, for just, represents that motion carrier is away from Network Access Point; If difference, for negative, represents that motion carrier is approaching Network Access Point.

Here, the distance accumulation that the present invention introduces change and method be at setting-up time section T _nin, the motion carrier and the distance d between Network Access Point (i) (i=1,2..., M) that get M sampling are worth, and can obtain T _nthe accumulated change of interior distance and, as shown in formula (1):

${\mathrm{\&Delta;D}}_n=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}[d\left(i\right)-d(i-1)],---\left(1\right);$

As Δ D _nduring > 0, judgement motion carrier is away from Network Access Point; As Δ D _nduring < 0, judgement motion carrier is approaching Network Access Point.Motion carrier accesses after approaching Network Access Point, can increase the time that network maintains to a certain extent, thereby reduces switching times.

Wherein, the distance d (i) between described current motion carrier and Network Access Point, is that the received signal strength RSS (i) receiving according to motion carrier determines, at setting-up time section T _nin, get RSS (i) value of sampling for M time, wherein, (i=1,2 ..., M), according to formula (2), determine the distance d (i) between sampling instant motion carrier and Network Access Point:

$d\left(i\right)={10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}\left(i\right)}{K_2}}---\left(2\right);$

Here, the switching probability P under the movement tendency of described motion carrier _h1probability distribution can pass through formula (3) and determine:

P _h1＝P(ΔD _n＜0) (3)；

In formula (3), Δ D _nfor network is at setting-up time section T _nin distance accumulation change and.

Due to P _th=P _h1therefore, can determine at network and continue the switching probability P that described mobile terminal under mode of priority switches to access network described in each _th:

$P_{\mathrm{th}}=P\left(\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}\right[{10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}\left(i\right)}{K_2}}-{10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}(i-1)}{K_2}}]<0)---\left(4\right);$

When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh;

Concrete, described peak transfer rate C is the important indicator that network is selected, and directly has influence on the quality of business on mobile terminal.Peak transfer rate C can determine according to Shannon's theorems formula (5):

$C={W\log }_2(1+\frac{\mathrm{RSS}\left(d\right)}{I\left(d\right)})---\left(5\right);$

In formula (5), W is frequency bandwidth,

for signal to noise ratio, the interference signal intensity that I (d) receives while being the distance d between motion carrier and Network Access Point.

Switching probability P under described peak transfer rate _h2probability distribution can pass through formula (6) and determine:

In formula (6), for the minimum transmission rate that can support that mobile terminal current business is required.

Due to P _bh=P _h2therefore, can determine that under network bandwidth mode of priority described mobile terminal switches to the switching probability P of a certain described access network _bh:

At network charges mode of priority or business, adapt under mode of priority, method by normalization numerical value is normalized network charges and service priority, and usings normalization numerical value α corresponding to network charges and as described mobile terminal under network charges mode of priority, switch to the switching probability P of a certain described access network _ch, that is: P _ch=α; The normalization numerical value that the network priority of also usining is corresponding switches to the switching probability of a certain described access network as described mobile terminal under business adaptation mode of priority.Wherein, the preference degree of normalization numeric representation user to network, normalized value shows that more greatly user is higher for this network preference degree.

Concrete, it is generally acknowledged that network charges does not change in a short time, therefore, the normalization numerical value after network charges is normalized has certain stability.Here, suppose that α is the normalization numerical value of the network charges of a certain access network, α _ibe the normalization numerical value of the network charges of i network (i=1,2,3), α _iconcrete value condition need to be in conjunction with the expense standard of real network.Concrete, for wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃, wlan network N ₁network charges normalization numerical value be α ₁, WiMAX network N ₂network charges normalization numerical value be α ₂, 3G Cellular network N ₃network charges normalization numerical value be α ₃.If the network charges of a certain access network is higher, normalization numerical value corresponding to the network charges of this access network is lower, that is: its corresponding normalization numerical value of network charges is inverse ratio.For instance, 3G Cellular network N ₃network charges higher than WiMAX network N ₂network charges, thereby have α ₃< α ₂.

By the analysis to four class Business Stream grades of 3GPP definition, the impact that business on mobile terminal is selected network is mainly session service, therefore, the present invention is divided into two large classes by the type of service on mobile terminal: contain session service and do not contain session service.Corresponding, need to containing session service and not containing the network priority that session service is corresponding, to be normalized numerical value processing respectively.For wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃, when containing session service, the priority of network is N ₃> N ₂> N ₁, when not containing session service, the priority of network is N ₁> N ₂> N ₃.

Suppose that β is that a certain described access network is at the normalization numerical value that contains session service mode of priority lower network priority, β _ibe that i network (i=1,2,3) is at the normalization numerical value that contains session service mode of priority lower network priority, β _ithe concrete value condition performance that need to contain session service in conjunction with the support of real network determine.Concrete, β ₁, β ₂and β ₃be respectively wlan network N ₁, WiMAX network N ₂with 3GCellular network N ₃at the normalization numerical value that contains session service mode of priority lower network priority.If the performance that a certain access network support contains session service is better, this access network is also higher at the normalization numerical value containing under session service mode of priority, that is: for a certain access network, support that its corresponding normalization numerical value of performance that contains session service is proportional.Due to wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃the performance of network own, when containing session service, the priority of network is N ₃> N ₂> N ₁, therefore, the corresponding normalization numerical value that three networks contain session service is β ₃> β ₂> β ₁.From above-mentioned analysis, can determine and contain described mobile terminal under session service mode of priority and switch to the switching probability P of a certain described access network _sh=β.

Suppose that γ is that a certain access network is at the normalization numerical value that does not contain session service mode of priority lower network priority, γ _ibe that i network (i=1,2,3) is at the normalization numerical value that does not contain session service mode of priority lower network priority, γ _ithe concrete value condition performance that need to not contain in conjunction with the support of real network session service determine.Concrete, γ ₁, γ ₂and γ ₃be respectively wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃at the normalization numerical value that does not contain session service mode of priority lower network priority.If the performance that a certain access network support does not contain session service is better, this network is also higher at the normalization numerical value not containing under session service mode of priority, that is: its corresponding normalization numerical value of performance of supporting not contain session service is proportional.Due to wlan network N ₁, WiMAX network N ₂with 3G Cellular network N ₃the performance of network own, when not containing session service, the priority of network is N ₁> N ₂> N ₃, therefore, the corresponding normalization numerical value that three access networks do not contain session service is γ ₁> γ ₂> γ ₃.From above-mentioned analysis, can determine and not contain described mobile terminal under session service mode of priority and switch to the switching probability P of a certain described access network _eh=γ.

Embodiment bis-:

The mode of priority that described user selects is network while continuing mode of priority, and described mobile terminal switches to the switching probability P of access network described in each _thfor: there is event h in described mobile terminal simultaneously ₃, h ₄, h ₅and h ₁probability P (h ₃h ₄h ₅h ₁);

When the mode of priority that described user selects is network bandwidth mode of priority, described mobile terminal switches to the switching probability P of access network described in each _bhfor: there is event h in described mobile terminal simultaneously ₃, h ₄, h ₅and h ₂probability P (h ₃h ₄h ₅h ₂);

When the mode of priority that described user selects is network charges mode of priority, described mobile terminal switches to the switching probability P of access network described in each _chfor: there is event h in described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value α of network charges;

The mode of priority that described user selects is when containing session service mode of priority, and described mobile terminal switches to the switching probability P of access network described in each _shfor: there is event h in described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value β of the network priority that contains session service;

The mode of priority that described user selects is not when containing session service mode of priority, and described mobile terminal switches to the switching probability P of access network described in each _ehfor: there is event h in described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value γ of the network priority that does not contain session service;

Here, h ₁for there is access network at setting-up time section T _nin distance accumulation change and be less than 0 event, h ₂for there is peak transfer rate, be greater than the event of the minimum transmission rate that can support that mobile terminal current business is required, h ₃for there is received signal strength, be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, h ₄for there is the error rate, be less than the event of the maximum bit error rate that meets mobile terminal service demand, h ₅for the event of blocking rate does not occur network, so there is P _h1=P (h ₁), P _h2=P (h ₂), P _h3=P (h ₃), P _h4=P (h ₄), P _h5=P (h ₅).

Here, determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅), comprising:

Determine described mobile terminal generation event h ₃probability P (h ₃)=P _h3;

Determine that described mobile terminal is at the event of generation h ₃basis on generation event h ₄probability P (h ₄| h ₃);

Determine that event h occurs described mobile terminal at the same time ₃and h ₄basis on generation event h ₅probability P (h ₅| h ₃h ₄);

Determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability,

P(h ₃h ₄h ₅)＝P(h ₃)*P(h ₄|h ₃)*P(h ₅|h ₃h ₄)。

Concrete, described received signal strength RSS triggers the vertical the most basic condition of switching, and it has reflected the quality of current channel.Received signal strength RSS is about the function apart from d, the received signal strength while representing the distance d between motion carrier and Network Access Point with RSS (d), and RSS (d) can pass through formula (8) and determine:

RSS(d)＝K ₁-K ₂lg(d)+u(x) (8)；

In formula (8), K ₁for transmitted power, K ₂for the path loss factor, d is the distance between motion carrier and Network Access Point; U (x) is interference signal intensity, and u (x) is 0 for obeying average, variance is σ ₂gaussian random distribution function, wherein, x is stochastic variable.

Switching probability P under described received signal strength _h3probability distribution can pass through formula (9) and determine:

P _h3＝P(RSS(d)＞η) (9)；

In formula (7), η is the required minimum signal strength threshold value of mobile terminal access corresponding network.

Concrete, described error rate BER is the function about signal to noise ratio (Signal-to-Noise Ratio, SNR).When the error rate of network is during higher than certain threshold value, show that network can not meet the demand of some business on mobile terminal.Error rate when BER (d) is the distance d between motion carrier and Network Access Point, can pass through formula (10) and determine:

$\mathrm{BER}\left(d\right)=Q\left(\sqrt{\frac{\mathrm{RSS}\left(d\right)}{I\left(d\right)}}\right),---\left(10\right);$

In formula (10), the expression formula of Q () is

wherein, y, t are stochastic variable.

Switching probability P under the described error rate _h4probability distribution can pass through formula (11) and determine:

P _h4＝P(BER(d)＜τ) (11)；

In formula (11), BER (d) is the error rate, and τ is the maximum bit error rate that meets mobile terminal service demand.

Concrete, described blocking rate BR is occupied when the channel of a certain Local Area Network, thereby cause new terminal traffic to be called out, will be refused by system.The number of channel of various wireless access technologys depends on the performance parameter of each communication system, after wireless network coverage area is normalized, determines the blocking rate P of k channel _kfor:

$P_k=\frac{\frac{{(-\mathrm{\&lambda;}{\mathrm{AX}}^{-1}e)}^k}{k!}}{\underset{n=0}{\overset{m}{\mathrm{\&Sigma;}}}\frac{{(-\mathrm{\&lambda;}{\mathrm{AX}}^{-1}e)}^n}{n!}}---\left(12\right);$

In formula (12), m is the total quantity of available channel in overlay area, and λ is the average arrival rate that in the unit interval, mobile terminal arrives access network, λ>=0, and n=0,1 ..., m, k=0,1 ..., m; A is the probability matrix that mobile terminal arrives network, A=(a ₁, a ₂..., a _n), e is rank, n * 1 unit vectors, X is service condition distribution matrix: $X=\left[\begin{array}{cccc}-u_1& h_{12}& \&CenterDot;\&CenterDot;\&CenterDot;& h_{1n}\\ h_{21}& -u_2& \&CenterDot;\&CenterDot;\&CenterDot;& h_{2n}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;\\ h_{n1}& h_{n2}& \&CenterDot;\&CenterDot;\&CenterDot;& -u_n\end{array}\right],$ Wherein ,-u ₁,-u ₂... ,-u _ndeparture rate for mobile terminal service; h _pqfor variable, description be state transition probability, p=1,2 ..., n, q=1,2 ..., n.

Due to the switching probability P under described blocking rate _h5=1-P _kso, the switching probability P under blocking rate _h5probability distribution can pass through formula (13) and determine:

$P_{h5}=1-\frac{\frac{{(-\mathrm{\&lambda;}{\mathrm{AX}}^{-1}e)}^m}{m!}}{\underset{n=0}{\overset{m}{\mathrm{\&Sigma;}}}\frac{{(-\mathrm{\&lambda;}{\mathrm{AX}}^{-1}e)}^n}{n!}}---\left(13\right).$

For guaranteeing that the present invention has higher practicality, determining of each parameter of network attribute and the movement tendency of motion carrier can obtain according to the statistics in setting-up time section under actual conditions, and each parameter of described network attribute comprises received signal strength, peak transfer rate, the error rate and blocking rate.And can determine according to various prior aries about the statistic processes of each parameter of network attribute and the movement tendency of motion carrier, repeat no more here.

P in the present embodiment _th, P _bh, P _ch, P _shand P _ehcan according to formula (14) to (18), determine respectively.Described in each, under mode of priority, definite method that described mobile terminal switches to the switching probability of each network is consistent, therefore, only provides definite formula here, as for detailed deterministic process, can determine according to prior art, repeats no more here.

P _th＝P(h ₁h ₃h ₄h ₅)＝P(h ₃)P(h ₄|h ₃)P(h ₅|h ₃h ₄)P(h ₁|h ₃h ₄h ₅) (14)；

P _bh＝P(h ₂h ₃h ₄h ₅)＝P(h ₃)P(h ₄|h ₃)P(h ₅|h ₃h ₄)P(h ₂|h ₃h ₄h ₅) (15)；

P _ch＝P(h ₃h ₄h ₅)α＝P(h ₃)P(h ₄|h ₃)P(h ₅|h ₃h ₄)α (16)；

P _sh＝P(h ₃h ₄h ₅)β＝P(h ₃)P(h ₄|h ₃)P(h ₅|h ₃h ₄)β (17)；

P _eh＝P(h ₃h ₄h ₅)γ＝P(h ₃)P(h ₄|h ₃)P(h ₅|h ₃h ₄)γ (18)；

Wherein, P (h ₃) P (h ₄| h ₃) P (h ₅| h ₃h ₄)=P (h ₃h ₄h ₅).

Wherein, P (h ₃)=P _h3for there is event h ₃probability, P (h ₄h ₃) be at the event of generation h ₃basis on generation event h ₄probability distribution, P (h ₄| h ₃) can pass through P (h ₃), P (h ₄) determine.P(h ₅| h ₃h ₄) for there is at the same time event h ₃and h ₄basis on generation event h ₅probability distribution; P(h ₁| h ₃h ₄h ₅) for there is at the same time event h ₃, h ₄and h ₅basis on generation event h ₁probability distribution; P(h ₂| h ₃h ₄h ₅) for there is at the same time event h ₃, h ₄and h ₅basis on generation event h ₂probability distribution; P(h ₃h ₄h ₅) for there is event h simultaneously ₃, h ₄and h ₅probability distribution.

When the described switching probability at current described access network is less than the switching probability of access network described in other, make described mobile terminal switch to the network in access network described in other, be specially:

At mobile terminal, select network to continue under mode of priority, if P _thi> P _th0, make mobile terminal switch to i network; Otherwise, make described mobile terminal keep the described current network of access; Wherein, P _th0for described mobile terminal under the lasting mode of priority of network switches to the switching probability of current network, P _bhi=max (P _bh1, P _bh2, P _bh3), P _bhibe i network at network, continue the switching probability that described mobile terminal under mode of priority switches to this access network, wherein, i=1,2,3.

At mobile terminal, select under network bandwidth mode of priority, if P _bhi> P _bh0, make mobile terminal switch to i network; Otherwise, make described mobile terminal keep the described current network of access; Wherein, P _bh0for described mobile terminal under network bandwidth mode of priority switches to the switching probability of current network, P _bhi=max (P _bh1, P _bh2, P _bh3), P _bhibe the switching probability that the described mobile terminal under network bandwidth mode of priority of i network switches to this access network, wherein, i=1,2,3.

At mobile terminal, select under network charges mode of priority, if P _chi> P _ch0, make mobile terminal switch to i network; Otherwise, make described mobile terminal keep the described current network of access; Wherein, P _ch0for described mobile terminal under network charges mode of priority switches to the switching probability of current network, P _chi=max (P _ch1, P _ch2, P _ch3), P _chibe the switching probability that the described mobile terminal under network charges mode of priority of i network switches to this access network, wherein, i=1,2,3.

Under mobile terminal selection business adapts to mode of priority, and current service of user terminal contains session service, if P _shi> P _sh0, make mobile terminal switch to i network; Otherwise, make described mobile terminal keep the described current network of access; Wherein, P _sh0for containing described mobile terminal under session service mode of priority and switching to the switching probability of current network, P _shi=max (P _sh1, P _sh2, P _sh3), P _shibeing i network is containing described mobile terminal under session service mode of priority and is switching to the switching probability of this access network, wherein, and i=1,2,3.

Under mobile terminal selection business adapts to mode of priority, and current service of user terminal do not contain session service, if P _ehi> P _eh0, make mobile terminal switch to i network; Otherwise, make described mobile terminal keep the described current network of access; Wherein, P _eh0for not containing described mobile terminal under session service mode of priority and switching to the switching probability of current network, P _ehi=max (P _eh1, P _eh2, P _eh3), P _ehibeing i network is not containing described mobile terminal under session service mode of priority and is switching to the switching probability of this access network, wherein, and i=1,2,3.

Vertical handoff method of the present invention is before step 101, also comprise the step that generates decision tree, step corresponding to the generation decision tree of embodiment mono-is specially: take at user option mode of priority as the first root node, the network of take respectively continues the event node that mode of priority, network bandwidth mode of priority and network charges mode of priority are described the first root node, the business of take adapts to the decision node that mode of priority is described the first root node, take respectively and has session service mode of priority and do not contain the event node that session service mode of priority is described decision node.Wherein, described event node represents this node, and event occurs, and described decision node is illustrated in decision process need to carry out Tactic selection at this point.

Fig. 3 is the structural representation of certainly selecting decision tree of vertical handoff method embodiment mono-of the present invention, as shown in Figure 3, certainly selecting in decision tree, square is decision node (Decision Node), and the decision node in decision tree is illustrated in decision process need to carry out Tactic selection at this point; Circle is event node (Event Node), and the event node in decision tree is illustrated in this occurrence of random events; Line is the branch of decision tree.Decision node a represents at user option mode of priority; Decision node b represents whether mobile terminal contains session service to current business and judge selection.Event node 1 represents whether access network occurs at setting-up time section T _ninterior distance accumulation changes and is less than 0 event, wherein, access network occurs at setting-up time section T _nin distance accumulation change and 0 the event of being less than is designated as event h ₁; Event node 2 represents whether to occur the event that peak transfer rate is greater than the minimum transmission rate that can support that mobile terminal current business is required, wherein, there is the event that peak transfer rate is greater than the minimum transmission rate that can support that mobile terminal current business is required and be designated as event h ₂; Event node 3 represents to select under network charges mode of priority, and expense normalization numerical value Network Based determines that mobile terminal switches to the event that a certain access network switches; Event node 4 and 5 represents that respectively selection business adapts to when containing session service and not containing session service under mode of priority, and priority normalization numerical value Network Based determines that mobile terminal switches to the event of a certain described access network generation network switching.Described decision tree be take decision node a as root node, take respectively the event node of event 1,2 and 3 under described root node, take the decision node of decision node b under decision node a, take respectively the event node of event 4 and 5 under decision node b.

Step corresponding to the generation decision tree of embodiment bis-is specially: whether to carry out to received signal received signal strength, detect and be chosen as the second root node, the first event node that the chance event that whether switches under the received signal strength detecting of take is described the second root node, the second event node that the whether satisfied chance event switching of the error rate of take is described the first event node, the 3rd event node that the whether satisfied chance event switching of the blocking rate of take is described second event node, take the decision node of at user option mode of priority under described the 3rd event node, with network, continue mode of priority respectively, network bandwidth mode of priority and network charges mode of priority are described decision node the 4th, the the 5th and the 6th event node, the business of take adapts to the sub-decision node that mode of priority is described the first decision node, take respectively and have session service mode of priority and do not contain session service mode of priority the 7th and the 8th event node that is described sub-decision node.

Fig. 4 is the structural representation of certainly selecting decision tree of vertical handoff method embodiment bis-of the present invention, as shown in Figure 4, certainly selecting in decision tree, square is decision node, and the decision node in decision tree is illustrated in decision process need to carry out Tactic selection at this point; Circle is event node, and the event node in decision tree is illustrated in this occurrence of random events; Line is the branch of decision tree.Decision node a represents at user option mode of priority; Decision node b represents whether mobile terminal contains session service to current business and judge selection; Decision node c represents to detect and select whether to carry out to received signal received signal strength; Event node 1 represents whether access network occurs at setting-up time section T _ninterior distance accumulation changes and is less than 0 event, wherein, access network occurs at setting-up time section T _nin distance accumulation change and 0 the event of being less than is designated as event h ₁; Event node 2 represents whether to occur the event that peak transfer rate is greater than the minimum transmission rate that can support that mobile terminal current business is required, wherein, there is the event that peak transfer rate is greater than the minimum transmission rate that can support that mobile terminal current business is required and be designated as event h ₂; Event node 3 represents to select under network charges mode of priority, and expense normalization numerical value Network Based determines that mobile terminal switches to the event that a certain access network switches; Event node 4 and 5 represents that respectively selection business adapts to when containing session service and not containing session service under mode of priority, and priority normalization numerical value Network Based determines that mobile terminal switches to the event of a certain described access network generation network switching.Event node 6 represents whether to occur received signal strength (Receive Signal Strength, RSS) be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, wherein, received signal strength occurring is greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network and is designated as event h ₃; Whether event node 7 there is the error rate (Bit Error Ratio, BER) be less than the event of the maximum bit error rate that meets mobile terminal service demand, wherein, the event that the generation error rate (Bit Error Ratio, BER) is less than the maximum bit error rate that meets mobile terminal service demand is designated as event h ₄; Event node 8 is illustrated in the event whether switching under blocking rate (BlockingRate, BR), and wherein, the event that network does not occur to block is designated as event h ₅.

Above-mentioned vertical handoff method is that the mode of priority that can select according to user by vertical handoff method of the present invention be determined optimum access network as objective network for three kinds of wireless network WLAN, WiMAX relating in the networking of existing car and 3G Cellular.In actual applications, if the wireless network relating in car networking is four kinds and when above, the mode of priority that those skilled in the art just can select according to user according to the general knowledge of this area is made corresponding expansion, thereby mobile terminal switches to optimum network, repeats no more here.

Fig. 5 is the composition structural representation of the vertical switching device shifter of the present invention, and as shown in Figure 5, described vertical switching device shifter comprises acquiring unit and switch unit, wherein,

Described acquiring unit 51, for obtaining the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects;

Here, described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority, and wherein said business adaptation mode of priority comprises and contains session service mode of priority and do not contain session service mode of priority.

Described switch unit 52, under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.

Further, when the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th;

When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh;

When the mode of priority that described user selects is network charges mode of priority, the normalization numerical value α of network charges of usining switches to the switching probability P of described access network as described mobile terminal under network charges mode of priority _ch;

The mode of priority that described user selects is when containing session service mode of priority, and normalization numerical value corresponding to network priority that contains session service of take is made β as containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _sh;

The mode of priority that described user selects when not containing session service mode of priority, is usingd and is not contained normalization numerical value γ that the network priority of session service is corresponding as not containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _eh.

Further, in described device, determine in the following manner the switching probability P under the movement tendency of described motion carrier _h1:

P _h1＝P(ΔD _n＜0)；

Wherein, $\mathrm{\&Delta;}{D}_n=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}[{10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}\left(i\right)}{K_2}}-{10}^{\frac{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003381627000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+u\left(x\right)-\mathrm{RSS}(i-1)}{K_2}}],$ Δ D _nchange for the distance accumulation of access network in setting-up time section and, K ₁for transmitted power, K ₂for the path loss factor, the computing function that u (x) is interference signal intensity, u (x) is 0 for obeying average, variance is σ ₂gaussian random distribution function, wherein, x is stochastic variable; M receives the number of times that intensity level is sampled, the received signal strength that RSS (i) is current sampling point, the received signal strength that RSS (i-1) is last sampled point for dock signal in described setting-up time section, i is current sampling number, i=1,2, ..., M.

Further, in described device, determine in the following manner the switching probability P under described peak transfer rate C _h2:

Wherein,

for the minimum transmission rate that can support that mobile terminal current business is required, described peak transfer rate

wherein, W is frequency bandwidth,

for signal to noise ratio, the interference signal intensity that I (d) receives while being the distance d between motion carrier and Network Access Point.

Further, the mode of priority that described user selects is network while continuing mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₁probability P (h ₃h ₄h ₅h ₁);

When the mode of priority that described user selects is network bandwidth mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₂probability P (h ₃h ₄h ₅h ₂);

When the mode of priority that described user selects is network charges mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value α of network charges;

The mode of priority that described user selects is when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value β of the network priority that contains session service;

The mode of priority that described user selects is not when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value γ of the network priority that does not contain session service;

Wherein, h ₁for there is network at setting-up time section T _nin distance accumulation change and be less than 0 event, h ₂for there is peak transfer rate, be greater than the event of the minimum transmission rate that can support that mobile terminal current business is required, h ₃for there is received signal strength, be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, h ₄for there is the error rate, be less than the event of the maximum bit error rate that meets mobile terminal service demand, h ₅for there is not the event of blocking in network.

Further, in described device, determine in the following manner that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅):

Determine described mobile terminal generation event h ₃probability P _h3=P (h ₃);

Determine that described mobile terminal is at the event of generation h ₃basis on generation event h ₄probability P (h ₄| h ₃);

Determine that event h occurs described mobile terminal at the same time ₃and h ₄basis on generation event h ₅probability P (h ₅| h ₃h ₄);

Determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅)=P (h ₃) * P (h ₄| h ₃) * P (h ₅| h ₃h ₄).

The practical function that it will be understood by those of skill in the art that each processing unit in the vertical switching device shifter shown in Fig. 5 and subelement thereof can be with reference to the associated description of aforementioned vertical handoff method and is understood.The function that it will be appreciated by those skilled in the art that each processing unit in the vertical switching device shifter shown in Fig. 5 can realize by the program running on processor, also can realize by concrete logical circuit.

Obviously, those skilled in the art should be understood that, above-mentioned each processing unit of the present invention or each step can realize with general calculation element, it can concentrate on single calculation element, or be distributed on the network that a plurality of calculation elements form, alternatively, it can be realized with the executable program code of calculation element, thereby, they can be stored in storage device and be carried out by calculation element, or they are made into respectively to each integrated circuit modules, or a plurality of modules in them or step are made into single integrated circuit module to be realized.Like this, the present invention is not restricted to any specific hardware and software combination.

The above, be only preferred embodiment of the present invention, is not intended to limit protection scope of the present invention.

Claims (10)

1. a vertical handoff method, is characterized in that, described method comprises:

Obtain the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects;

Under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.

2. method according to claim 1, it is characterized in that, described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority, wherein, described business adapts to mode of priority and comprises and contain session service mode of priority and do not contain session service mode of priority.

3. method according to claim 2, is characterized in that, when the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th; Wherein, determine in the following manner the switching probability P under the movement tendency of described motion carrier _h1:

P _h1＝P(ΔD _n＜0)；

Wherein, $\mathrm{\&Delta;}{D}_n=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}[{10}^{\frac{K_1+u\left(x\right)-\mathrm{RSS}\left(i\right)}{K_2}}-{10}^{\frac{K_1+u\left(x\right)-\mathrm{RSS}(i-1)}{K_2}}],$ Δ D _nchange for the distance accumulation of access network in setting-up time section and, K ₁for transmitted power, K ₂for the path loss factor, the computing function that u (x) is interference signal intensity, u (x) is 0 for obeying average, variance is σ ₂gaussian random distribution function, wherein, x is stochastic variable; M receives the number of times that intensity level is sampled, the received signal strength that RSS (i) is current sampling point, the received signal strength that RSS (i-1) is last sampled point for dock signal in described setting-up time section, i is current sampling number, i=1,2, ..., M;

When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh; Wherein, determine in the following manner the switching probability P under described peak transfer rate C _h2:

Wherein,

for the minimum transmission rate that can support that mobile terminal current business is required, described peak transfer rate

wherein, W is frequency bandwidth,

for signal to noise ratio, the interference signal intensity that I (d) receives while being the distance d between motion carrier and Network Access Point;

When the mode of priority that described user selects is network charges mode of priority, the normalization numerical value α of network charges of usining switches to the switching probability P of described access network as described mobile terminal under network charges mode of priority _ch;

The mode of priority that described user selects is when containing session service mode of priority, and normalization numerical value β corresponding to the network priority that contains session service of usining is as containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _sh;

The mode of priority that described user selects when not containing session service mode of priority, is usingd and is not contained normalization numerical value γ that the network priority of session service is corresponding as not containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _eh.

4. method according to claim 2, is characterized in that,

The mode of priority that described user selects is network while continuing mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₁probability P (h ₃h ₄h ₅h ₁);

When the mode of priority that described user selects is network bandwidth mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₂probability P (h ₃h ₄h ₅h ₂);

When the mode of priority that described user selects is network charges mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value α of network charges;

The mode of priority that described user selects is when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value β of the network priority that contains session service;

The mode of priority that described user selects is not when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value γ of the network priority that does not contain session service;

Wherein, h ₁for there is access network at setting-up time section T _nin distance accumulation change and be less than 0 event, h ₂for there is peak transfer rate, be greater than the event of the minimum transmission rate that can support that mobile terminal current business is required, h ₃for there is received signal strength, be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, h ₄for there is the error rate, be less than the event of the maximum bit error rate that meets mobile terminal service demand, h ₅for there is not the event of blocking in network.

5. method according to claim 4, is characterized in that, described method also comprises:

Determine that in the following manner event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅),

Determine described mobile terminal generation event h ₃probability P _h3=P (h ₃);

Determine that described mobile terminal is at the event of generation h ₃basis on generation event h ₄probability P (h ₄| h ₃);

Determine that event h occurs described mobile terminal at the same time ₃and h ₄basis on generation event h ₅probability P (h ₅| h ₃h ₄);

Determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅)=P (h ₃) * P (h ₄| h ₃) * P (h ₅| h ₃h ₄).

6. a vertical switching device shifter, is characterized in that, described device comprises: acquiring unit and switch unit, wherein,

Described acquiring unit, for obtaining the information of current each access network that can access of mobile terminal on motion carrier and the mode of priority that user selects;

Described switch unit, under the mode of priority of selecting described user, determine that described mobile terminal switches to the switching probability of access network described in each, and when the switching probability of access network described in the switching probability of current described access network is less than other, make described mobile terminal switch to the network in access network described in other.

7. device according to claim 6, it is characterized in that, described mode of priority comprises that network continues mode of priority, network bandwidth mode of priority, network charges mode of priority and business and adapts to mode of priority, and wherein said business adaptation mode of priority comprises and contains session service mode of priority and do not contain session service mode of priority.

8. device according to claim 7, is characterized in that, when the mode of priority that described user selects is the lasting mode of priority of network, with the switching probability P under the movement tendency of described motion carrier _h1as described mobile terminal under the lasting mode of priority of network, switch to the switching probability P of described access network _th; Wherein, determine in the following manner the switching probability P under the movement tendency of described motion carrier _h1:

P _h1＝P(ΔD _n＜0)；

Wherein, $\mathrm{\&Delta;}{D}_n=\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}[{10}^{\frac{K_1+u\left(x\right)-\mathrm{RSS}\left(i\right)}{K_2}}-{10}^{\frac{K_1+u\left(x\right)-\mathrm{RSS}(i-1)}{K_2}}],$ Δ D _nchange for the distance accumulation of access network in setting-up time section and, K ₁for transmitted power, K ₂for the path loss factor, the computing function that u (x) is interference signal intensity, u (x) is 0 for obeying average, variance is σ ₂gaussian random distribution function, wherein, x is stochastic variable; M receives the number of times that intensity level is sampled, the received signal strength that RSS (i) is current sampling point, the received signal strength that RSS (i-1) is last sampled point for dock signal in described setting-up time section, i is current sampling number, i=1,2, ..., M;

When the mode of priority that described user selects is network bandwidth mode of priority, with the switching probability P under peak transfer rate _h2as described mobile terminal under network bandwidth mode of priority, switch to the switching probability P of described access network _bh; Wherein, determine in the following manner the switching probability P under described peak transfer rate C _h2:

Wherein,

for the minimum transmission rate that can support that mobile terminal current business is required, described peak transfer rate

wherein, W is frequency bandwidth,

for signal to noise ratio, the interference signal intensity that I (d) receives while being the distance d between motion carrier and Network Access Point;

When the mode of priority that described user selects is network charges mode of priority, the normalization numerical value α of network charges of usining switches to the switching probability P of described access network as described mobile terminal under network charges mode of priority _ch;

The mode of priority that described user selects is when containing session service mode of priority, and normalization numerical value β corresponding to the network priority that contains session service of usining is as containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _sh;

The mode of priority that described user selects when not containing session service mode of priority, is usingd and is not contained normalization numerical value γ that the network priority of session service is corresponding as not containing described mobile terminal under session service mode of priority and switch to the switching probability P of described access network _eh.

9. device according to claim 7, is characterized in that,

The mode of priority that described user selects is network while continuing mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₁probability P (h ₃h ₄h ₅h ₁);

When the mode of priority that described user selects is network bandwidth mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄, h ₅and h ₂probability P (h ₃h ₄h ₅h ₂);

When the mode of priority that described user selects is network charges mode of priority, described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value α of network charges;

The mode of priority that described user selects is when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value β of the network priority that contains session service;

The mode of priority that described user selects is not when containing session service mode of priority, and described mobile terminal switches to the switching probability of access network described in each and is: event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅) and be multiplied by the normalization numerical value γ of the network priority that does not contain session service;

Wherein, h ₁for there is network at setting-up time section T _nin distance accumulation change and be less than 0 event, h ₂for there is peak transfer rate, be greater than the event of the minimum transmission rate that can support that mobile terminal current business is required, h ₃for there is received signal strength, be greater than the event that described mobile terminal can access the required minimum received signal strength threshold value of corresponding network, h ₄for there is the error rate, be less than the event of the maximum bit error rate that meets mobile terminal service demand, h ₅for there is not the event of blocking in network.

10. device according to claim 9, is characterized in that, described device determines that event h occurs described mobile terminal simultaneously in the following manner ₃, h ₄and h ₅probability P (h ₃h ₄h ₅):

Determine described mobile terminal generation event h ₃probability P _h3=P (h ₃);

Determine that described mobile terminal is at the event of generation h ₃basis on generation event h ₄probability P (h ₄| h ₃);

Determine that event h occurs described mobile terminal at the same time ₃and h ₄basis on generation event h ₅probability P (h ₅| h ₃h ₄);

Determine that event h occurs described mobile terminal simultaneously ₃, h ₄and h ₅probability P (h ₃h ₄h ₅)=P (h ₃) * P (h ₄| h ₃) * P (h ₅| h ₃h ₄).

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