CN102802223B - Vertical switching method of wireless heterogeneous networks and user terminal - Google Patents

Abstract

The invention relates to a communication technology, solves the problem that most of the traditional methods for vertical switching among wireless heterogeneous networks do not focus on the state of a user terminal, and provides a vertical switching method of the wireless heterogeneous networks and a user terminal. A technical scheme disclosed by the invention is summarized as follows: in the vertical switching method of the wireless heterogeneous networks, three standby modes, including a motion pattern, a normal pattern and a low electric quantity mode, of the user terminal are defined at first, then, the user terminal determines whether to trigger network switching according to a communication condition, and after judging that the network switching needs to be triggered, the user terminal selects to access a universal mobile telecommunication system (UMTS) or a selected wireless local area network (WLAN) according to the standby modes or a communication mode. The vertical switching method disclosed by the invention has the beneficial effects of guaranteeing the user terminal to access the most appropriate network accurately and efficiency under a UMTS and WLAN multi-coverage environment and being applicable to a mobile terminal.

Description

The vertical handoff method of Wireless Heterogeneous Networks and user terminal

Technical field

The present invention relates to the communication technology, the Vertical Handoff Technology between the Wireless Heterogeneous Networks that particularly subscriber terminal equipment accesses.

Background technology

In recent years, mobile communication and wireless access wide band technology fast development, its developing goal be make anyone at any time, any place can carry out any type of communication with anyone.Reach this target, existing wireless network and following issuable new network access technology must be merged, jointly for user terminal provides ubiquitous collaborative isomerization access network.Prior wireless network mainly comprises wide area cellular mobile communications network (typical cellular system is as 2G/3G/B3G etc.), and take the WiMAX access technology that IEEE802 series standard is representative, as Wireless Personal Network (WPAN, Wireless Personal Area Network), WLAN (wireless local area network) (WLAN, Wireless Local Area Network) and wireless MAN (WMAN, Wireless Metropolitan Area Network) etc.These heterogeneous networks are different at aspects such as application background, system configuration, developing direction, coverage, link property and quality of service ranks, and user can realize by multimode terminal and accessing across frequency range, completes information transmission and the communication of multiclass channel.

Under the environment of the overlapping covering of heterogeneous network, in order to make full use of heterogeneous network performance advantage separately, allow user terminal realize and always access optimal network (ABC, Always Best Connected), to ensure, obtain best communication experiences, the vertical handoff method between heterogeneous network plays vital effect.Many scholars and research institution have launched research to this problem, up to now, multiple vertical switch decision algorithm has been proposed, can be summarized as: based on received signal strength (RSS, Received Signal Strength) vertical handoff algorithms, handoff algorithms based on cost function (cost function), handoff algorithms based on prediction and the vertical handoff algorithms of self adaptation based on fuzzy neural network etc., the vertical handoff algorithms of above heterogeneous network respectively has its advantage, but mostly do not pay close attention to the state of user terminal, although relate to the state of some terminal in indivedual algorithms, but do not segment.Existing these algorithms or too simple, be difficult to effectively judge best alternative network, although or the network of selectivity optimum accurately, algorithm complex is too high, need user terminal to possess higher analytical calculation ability, easily cause higher switching delay.And along with the continuing to bring out of the multimedia services such as video request program, the terminal standby time has caused showing great attention to of user.In addition, user terminal is often in high-speed moving state, and this selection on network has caused very large impact, therefore need to investigate in detail the state of user terminal.On the other hand, in order to ensure the QoS of user terminal communication, should, when guaranteeing algorithm validity, reduce the complexity of algorithm, thereby reduce handover delay.

Summary of the invention

Object of the present invention is exactly in the vertical handoff method overcoming between current Wireless Heterogeneous Networks, mostly not pay close attention to the shortcoming of user terminal state, and a kind of vertical handoff method and user terminal of Wireless Heterogeneous Networks is provided.

The present invention solves its technical problem, and the technical scheme of employing is that the vertical handoff method of Wireless Heterogeneous Networks, is characterized in that, comprises the following steps:

A. three kinds of standby modes that define user terminal, comprise motor pattern, normal mode and Low Power Mode;

B. user terminal determines whether to want trigger network to switch according to signal intelligence, and concrete grammar is:

When B1. user terminal does not carry out any communication, when standby mode changes, trigger user terminal the signal strength signal intensity of current access network is detected, if the signal strength signal intensity of current access network detected lower than the signal strength threshold value of setting, trigger network switches;

When B2. user terminal will initiating communication, if current access network detected, cannot meet the required communication quality of its business, trigger network switches;

B3. user terminal is in communication process, and when current access network being detected and cannot meet the required communication quality of its business, trigger network switches;

After C, user terminal judge that in step B trigger network switches, the concrete grammar of switching and network access is:

C1. user terminal judges that its standby mode will be when motor pattern and/or its will carry out or carry out real time business communication, selects access universal mobile telecommunications system UMTS;

When C2. user terminal judges its standby mode in Low Power Mode and does not initiate or carry out real time business communication, and while judging the WLAN (wireless local area network) WLAN that current nothing satisfies condition, select access UMTS, otherwise select access WLAN according to the alternative condition of setting;

C3. user terminal judges its standby mode in normal mode and does not initiate or carry out real time business when communication, and judges currently while there is no accessible WLAN, selects access UMTS, otherwise selects access network according to the alternative condition of setting.

Preferably, in described steps A, the concrete grammar of three kinds of standby modes of definition user terminal is that the decision condition of three kinds of standby modes of setting, is specially:

When user terminal translational speed surpasses the speed threshold value of setting, be judged to be motor pattern;

When user terminal electric weight lower than set electric weight threshold value time, be judged to be Low Power Mode;

When user terminal in static or translational speed lower than the threshold value of setting, and electric weight higher than set electric weight threshold value time, be judged to be normal mode.

Preferably, the speed threshold value of described setting is 1.5m/s; The electric weight threshold value of described setting is 20% of the total electric weight of described user terminal battery.

Preferably, described communication quality refers to network delay and error rate requirement.

Preferably, described step C2 specifically comprises the steps:

When user terminal judges its standby mode in Low Power Mode and do not initiate or carry out real time business communication, according to following Rule of judgment, select access network:

Judge currently while there is no accessible WLAN, select access UMTS;

When the bandwidth that judges the accessible WLAN of current existence and current accessible WLAN does not meet the bandwidth threshold value of setting, select access UMTS;

Judge when WLAN of current existence and its bandwidth meet the bandwidth threshold value of setting, select this WLAN of access;

While judging the current WLAN that has a bandwidth threshold value that a plurality of bandwidth meet to set, the WLAN of the gravitation maximum that the gravitation judgement formula that selective basis is set calculates accesses.

Preferably, described step C3 specifically comprises the steps:

When user terminal judges its standby mode in normal mode and do not initiate or carry out real time business communication, according to following Rule of judgment, select access network:

Judge currently while there is no accessible WLAN, select access UMTS;

When the bandwidth that judges the accessible WLAN of current existence and current accessible WLAN does not meet the bandwidth threshold value of setting, select access UMTS;

While judging the current WLAN that has a bandwidth threshold value that bandwidth meet to set, the network that meets the gravitation maximum that gravitation judgement formula that in the WLAN of the bandwidth threshold value of setting and UMTS, selective basis is set calculates in described bandwidth accesses.

Preferably, the signal strength threshold value of described setting is-90dbm; Described bandwidth threshold value is 9.6kbps.Preferably, the gravitation of described setting judgement formula is:

Wherein, F _nfor the gravitation of access network N to user terminal T, M _nfor the quality of access network N, M _tfor the quality of user terminal T, R be user terminal T to base station or the distance of Network Access Point, k is invariant;

M _ncomputing formula be: $M_N=B_N+\frac{1}{D_N}+\frac{1}{E_N}+\frac{1}{C_N},$

Wherein, B _n, D _n, E _n, C _nthe network availability bandwidth B of the access network N detecting while being respectively switching judging in step C _n, end-to-end delay D _n, error rate E _nwith Internet utilization fee C _nnormalized value;

The quantity of the access network that current participation is calculated is m, B _ncomputing formula be:

D _ncomputing formula be: $D_N=\frac{\frac{1}{D_n}}{\max (\frac{1}{D_1},\frac{1}{D_2},...,\frac{1}{D_m})},$

E _ncomputing formula be: $E_N=\frac{\frac{1}{E_n}}{\max (\frac{1}{E_1},\frac{1}{E_2},...,\frac{1}{E_m})},$

C _ncomputing formula be: $C_N=\frac{\frac{1}{C_n}}{\max (\frac{1}{C_1},\frac{1}{C_2},...,\frac{1}{C_m})}.$

Preferably, described k is 1; Described M _tbe 1; Described R is that user terminal T is to base station or the actual range D of network N access point and map network covering radius R _nratio, its computing formula is:

$R=\frac{D}{R_N}.$

Another object of the present invention, provides a kind of user terminal, comprising:

Standby mode definition module, for judging that the user terminal at place is current in which kind of standby mode, described standby mode specifically comprises motor pattern, normal mode and Low Power Mode, when user terminal translational speed surpasses the speed threshold value of setting, is judged to be motor pattern; When user terminal electric weight lower than set electric weight threshold value time, be judged to be Low Power Mode; When user terminal in static or translational speed lower than the threshold value of setting, and electric weight higher than set electric weight threshold value time, be judged to be normal mode;

Switch detection module, for detecting according to the signal intelligence of place user terminal and determining whether to want trigger network to switch, and notice is switched selection module; Specifically for when user terminal does not carry out any communication, when standby mode changes, trigger user terminal the signal strength signal intensity of current access network is detected, if the signal strength signal intensity of current access network detected lower than the signal strength threshold value of setting, notice is switched the switching of selection module trigger network; When user terminal will initiating communication, if current access network detected, cannot meet the required communication quality of its business, notice is switched and is selected module trigger network to switch; When user terminal is in communication process, when current access network being detected and cannot meet the required communication quality of its business, notice is switched and is selected module trigger network to switch;

Switch and select module, for after receiving the notice of switch detection module, according to the alternative condition switching and network access of setting; Specifically for the standby mode when obtain user terminal from standby mode definition module, when motor pattern and/or user terminal will carry out or carry out real time business communication, select access universal mobile telecommunications system UMTS; When the standby mode that obtains user terminal from standby mode definition module is in Low Power Mode and when not initiating or carrying out real time business communication, and while judging the WLAN (wireless local area network) WLAN that current nothing satisfies condition, select access UMTS, otherwise select access WLAN according to the alternative condition of setting; When the standby mode that obtains user terminal from standby mode definition module is in normal mode and do not initiate or carry out real time business communication, and judge current while there is no accessible WLAN, select access UMTS, otherwise select access network according to the alternative condition of setting.

The invention has the beneficial effects as follows, in the present invention program, by vertical handoff method and the user terminal of above-mentioned Wireless Heterogeneous Networks, according to self-defining standby mode, improve judgement speed and the accuracy switched, and in conjunction with the law of universal gravitation, network gravitation judgement formula is proposed, make the judgement of network performance succinctly efficient, implementation process takes into full account the performance of user terminal and network terminal, ensures the optimal network of access that user terminal can precise and high efficiency under the environment of UMTS and the multiple covering of WLAN.

Accompanying drawing explanation

Fig. 1 is the residing Wireless Heterogeneous Networks environment of embodiment of the present invention multimode user terminal schematic diagram.

Fig. 2 is the vertical handoff method flow chart of embodiment of the present invention Wireless Heterogeneous Networks.

Fig. 3 is the trigger timing decision flow chart that embodiment of the present invention network switches.

Fig. 4 is that the embodiment of the present invention redefines access network flow chart.

Fig. 5 is the structured flowchart of inventive embodiments user terminal.

Embodiment

Below in conjunction with embodiment and accompanying drawing, describe technical scheme of the present invention in detail.

The residing Wireless Heterogeneous Networks environment of embodiment of the present invention multimode user terminal (mobile phone) schematic diagram is as Fig. 1, and the accessible network of described user terminal has WLAN1, WLAN2 and universal mobile telecommunications system UMTS.The vertical handoff method flow chart of the Wireless Heterogeneous Networks that is the embodiment of the present invention referring to Fig. 2, specifically comprises the steps:

Step 201, first defines three kinds of standby modes of user terminal, comprises motor pattern, normal mode and Low Power Mode.Consider the vertical principal element of switching of impact, the factors such as the translational speed of high spot reviews user terminal, battery electric quantity, three kinds of standby modes of definition user terminal: motor pattern, Low Power Mode and normal mode.The concrete grammar of three kinds of standby modes of definition user terminal is that the decision condition of three kinds of standby modes of setting, is specially:

(a) motor pattern: when user terminal translational speed surpasses the speed threshold value of setting, be judged to be motor pattern.In view of the coverage difference of UMTS and WLAN is larger, and two kinds of networks are different to the ambulant support of user terminal, consider the high-speed moving state of user terminal, the motor pattern of definition user terminal simultaneously.Under normal circumstances, people's walking speed is 1.1 ~ 1.5m/s, so setting speed threshold value V _th=1.5m/s, the speed that definition is moved when user terminal is higher than V _thtime, the standby mode of user terminal is motor pattern.Wherein, obtaining of user terminal translational speed can adopt the prior aries such as GPS tests the speed.

(b) Low Power Mode: when user terminal electric weight lower than set electric weight threshold value time, be judged to be Low Power Mode.Along with the application of the multimedia services such as video calling, video request program, the stand-by time of terminal has caused showing great attention to of user.In order to improve the stand-by time of user terminal, ensure normally carrying out of different QoS business as far as possible, reduce the generation that exhausts the situation of the termination communication of having to because of electric weight, the Low Power Mode of definition user terminal.When user terminal electric weight is lower than set electric weight threshold value P _thtime, the residing standby mode of user terminal is Low Power Mode.P for example _th=0.2P, total electric weight that wherein P is battery, user can set electric weight threshold value voluntarily according to the power consumption of total electric weight of end cell and conventional business.

(c) normal mode: when user terminal in static or translational speed lower than the threshold value of setting, and electric weight higher than set electric weight threshold value time, be judged to be normal mode.When user terminal is normal mode in standby mode static or when mobile status (speed is less than 1.5m/s) and electric weight are sufficient at a slow speed.

Step 202, user terminal determines whether to want trigger network to switch according to signal intelligence.Determining of concrete network handover trigger opportunity.In order to improve the accuracy of switching, in the embodiment of the present invention, whether we communicate and adopt three kinds of different strategies to determine the trigger timing that network switches according to user terminal, referring to Fig. 3, the trigger timing decision flow chart for embodiment of the present invention network switches, comprises the steps:

Step 2021, when user terminal does not carry out any communication, when standby mode changes, trigger user terminal the signal strength signal intensity of current access network is detected, if the signal strength signal intensity of current access network detected lower than the signal strength threshold value (90dbm) of setting, trigger network switches.

Step 2022, when user terminal will initiating communication, cannot meet the required communication quality of its business if current access network detected, and trigger network switches.When user terminal will initiating communication, according to its type of traffic and current accessed network, judge whether to switch, for example that the access of active user's terminal is WALN, and user terminal will carry out voice call, in order to ensure communication quality, trigger network switches.Described communication quality refers to network delay and error rate requirement.

Step 2023, user terminal is in communication process, and when current access network being detected and cannot meet the required communication quality of its business, trigger network switches.During user terminal ongoing communication, if the communication quality non-constant that becomes in communication process, for example time delay becomes is greater than time delay threshold value very much, to such an extent as to affected, implements normally carrying out of communication service, and trigger network switches.Regulation according to 3GPP to QoS of survice, the delay requirement of the real time business such as speech, real time data is second-time, the delay requirement of non-real-time service is a minute magnitude, therefore, desirable 100 milliseconds of threshold value).

Step 203, user terminal is after judgement trigger network switches, according to the alternative condition switching and network access of setting.After network handover trigger, according to default condition, determine best access network.The described detailed process that redefines access network, vertical switch decision flow chart, referring to Fig. 4, comprises the steps:

(a) user terminal judges that its standby mode will be when motor pattern and/or its will carry out or carry out real time business communication, selects access universal mobile telecommunications system UMTS.To reduce, because user terminal shifts out the overlay area of WLAN in the short time, again switching the communication quality causing declines and energy consumption.

(b), when user terminal judges its standby mode in Low Power Mode and does not initiate or carry out real time business communication, and while judging the WLAN (wireless local area network) WLAN that current nothing satisfies condition, select access UMTS, otherwise select access WLAN according to the alternative condition of setting.If user terminal is in Low Power Mode and do not initiate or carry out real time business when communication, first consider access WLAN, because the sending and receiving power consumption of user terminal is relatively low in the less wlan network of coverage, can extend the operating time of user terminal.Consider that WLAN adopts the technology of sharing frequency band, the situation that often band bandwidth of each WALN of generation covering user terminal has been carved up by many user terminals.For fear of switching frequently, the available bandwidth of first investigating each WALN that covers user terminal can not be lower than bandwidth threshold value B _th(for example 9.6kbps), if the accessible WLAN that has a plurality of bandwidth to satisfy condition adjudicates according to the gravitation of setting the gravitation that formula calculates each alternative WLAN, selects the network of access gravitation maximum, otherwise access UMTS, concrete deterministic process is as follows:

Judge currently while there is no accessible WLAN, select access UMTS; When the bandwidth that judges the accessible WLAN of current existence and current accessible WLAN does not meet the bandwidth threshold value of setting, select access UMTS;

Judge when WLAN of current existence and its bandwidth meet the bandwidth threshold value of setting, select this WLAN of access;

While judging the current WLAN that has a bandwidth threshold value that a plurality of bandwidth meet to set, the WLAN of the gravitation maximum that the gravitation judgement formula that selective basis is set calculates accesses.

(c), user terminal judges its standby mode in normal mode and do not initiate or carry out real time business when communication, and judges currently while there is no accessible WLAN, selects access UMTS, otherwise selects access network according to the alternative condition of setting.The reason based on mentioning in step (b), first detect the accessible WLAN that whether has bandwidth to satisfy condition, if do not have the accessible WLAN that bandwidth satisfies condition to access UMTS, otherwise calculate each accessible WLAN and the gravitation of UMTS to user terminal according to the gravitation judgement company setting, user terminal is the network of gravitation maximum by alternative access performance optimum, and concrete deterministic process is as follows:

When user terminal judges its standby mode in normal mode and do not initiate or carry out real time business communication, according to following Rule of judgment, select access network:

Judge currently while there is no accessible WLAN, select access UMTS;

When the bandwidth that judges the accessible WLAN of current existence and current accessible WLAN does not meet the bandwidth threshold value of setting, select access UMTS;

While judging the current WLAN that has a bandwidth threshold value that bandwidth meet to set, the network that meets the gravitation maximum that gravitation judgement formula that in the WLAN of the bandwidth threshold value of setting and UMTS, selective basis is set calculates in described bandwidth accesses.

In the present embodiment, in user terminal, defined gravitation judgement formula.Gravitation computing formula in the law of universal gravitation that newton proposes between object is show two gravitation between object, be directly proportional to their product of quality, with square being inversely proportional to of their distances.For distance two certain objects of (R), one of them mass of object is larger, and it is also larger to the gravitation of another object.Based on this gravity model, we introduce the gravitation judgement formula of network to user terminal, are used for weighing the performance of certain network.We are analogous to respectively two objects in the law of universal gravitation by network and user terminal, the performance of network is better, the quality that is analogous to an object in the law of universal gravitation is larger, and this object is also larger to the gravitation of another object, and network is also larger to the gravitation of user terminal.User terminal is selected access using the network of gravitation maximum as optimum network.

Definition access network N is F to the gravitation of user terminal T _n, computing formula is:

$F_N=k\frac{M_N{M}_T}{R^2}$

Wherein, M _nand M _trepresent respectively " quality of access network N " and " quality of user terminal T ", R is the distance of user terminal T (BS) or network N access point (AP) to base station, and k is invariant, is similar to the acceleration of gravity G in the law of universal gravitation.In the present invention, consider that heterogeneous networks is in the calculating of the gravitation of user terminal, the value of k is all identical.For simplifying, calculate, the value of invariant k is 1.

In order to reflect the performance of a network comprehensively, we consider network level and application is chosen most important four factors: network availability bandwidth B, end-to-end delay D, error rate E and Internet utilization fee are carried out define grid mass M with C _n, its computing formula is:

$M_N=B_N+\frac{1}{D_N}+\frac{1}{E_N}+\frac{1}{C_N}$

Wherein, B _n, D _n, E _nand C _nthe network availability bandwidth B of the network N monitoring while being respectively switch decision _n, end-to-end delay D _n, error rate E _nwith Internet utilization fee C _nnormalized value.Their computing formula (supposing total m alternative network) is respectively: $B_N=\frac{B_n}{\max (B_1,B_2,...,B_m)},$ $D_N=\frac{\frac{1}{D_n}}{\max (\frac{1}{D_1},\frac{1}{D_2},...,\frac{1}{D_m})},$ $E_N=\frac{\frac{1}{E_n}}{\max (\frac{1}{E_1},\frac{1}{E_2},...,\frac{1}{E_m})},$ $C_N=\frac{\frac{1}{C_n}}{\max (\frac{1}{C_1},\frac{1}{C_2},...,\frac{1}{C_m})}.$

For improving arithmetic speed, reduce the judgement time used, get user terminal T mass M _tfor constant 1.The coverage of considering UMTS and WLAN differs larger, and getting R is here that user terminal is to actual range D and the map network covering radius R of BS or AP _nratio, its computing formula is:

The embodiment of the present invention also provides a kind of user terminal of implementing above-mentioned Wireless Heterogeneous Networks vertical handoff method, and the structured flowchart of described user terminal, referring to Fig. 5, comprising:

Standby mode definition module, for judging that the user terminal at place is current in which kind of standby mode, described standby mode specifically comprises motor pattern, normal mode and Low Power Mode, when user terminal translational speed surpasses the speed threshold value of setting, is judged to be motor pattern; When user terminal electric weight lower than set electric weight threshold value time, be judged to be Low Power Mode; When user terminal in static or translational speed lower than the threshold value of setting, and electric weight higher than set electric weight threshold value time, be judged to be normal mode;

Switch detection module, for detecting according to the signal intelligence of place user terminal and determining whether to want trigger network to switch, and notice is switched selection module; Specifically for when user terminal does not carry out any communication, when standby mode changes, trigger user terminal the signal strength signal intensity of current access network is detected, if the signal strength signal intensity of current access network detected lower than the signal strength threshold value of setting, notice is switched the switching of selection module trigger network; When user terminal will initiating communication, if current access network detected, cannot meet the required communication quality of its business, notice is switched and is selected module trigger network to switch; When user terminal is in communication process, when current access network being detected and cannot meet the required communication quality of its business, notice is switched and is selected module trigger network to switch;

Switch and select module, for after receiving the notice of switch detection module, according to the alternative condition switching and network access of setting; Specifically for the standby mode when obtain user terminal from standby mode definition module, when motor pattern and/or user terminal will carry out or carry out real time business communication, select access universal mobile telecommunications system UMTS; When the standby mode that obtains user terminal from standby mode definition module is in Low Power Mode and when not initiating or carrying out real time business communication, and while judging the WLAN (wireless local area network) WLAN that current nothing satisfies condition, select access UMTS, otherwise select access WLAN according to the alternative condition of setting; When the standby mode that obtains user terminal from standby mode definition module is in normal mode and do not initiate or carry out real time business communication, and judge current while there is no accessible WLAN, select access UMTS, otherwise select access network according to the alternative condition of setting.

The present invention provides a kind of solution rapidly and efficiently for how multimode user terminal is switched to optimal network under the environment of the overlapping covering of heterogeneous wireless network, the design feature of this heterogeneous network vertical handoff method based on next generation wireless network and the communication requirement of user terminal, can make user terminal ensure under the prerequisite of communication QoS, precise and high efficiency be switched to most suitable network, thereby can make full use of the resources advantage of heterogeneous network, realize best communication experiences.

Claims (10)

1. the vertical handoff method of Wireless Heterogeneous Networks, is characterized in that, comprises the following steps:

A. three kinds of standby modes that define user terminal, comprise motor pattern, normal mode and Low Power Mode;

B. user terminal determines whether to want trigger network to switch according to signal intelligence, and concrete grammar is:

When B1. user terminal does not carry out any communication, when standby mode changes, trigger user terminal the signal strength signal intensity of current access network is detected, if the signal strength signal intensity of current access network detected lower than the signal strength threshold value of setting, trigger network switches;

When B2. user terminal will initiating communication, if current access network detected, cannot meet the required communication quality of its business, trigger network switches;

B3. user terminal is in communication process, and when current access network being detected and cannot meet the required communication quality of its business, trigger network switches;

After C, user terminal judge that in step B trigger network switches, according to the alternative condition switching and network access of setting, concrete grammar is:

C1. user terminal judges that its standby mode will be when motor pattern and/or its will carry out or carry out real time business communication, selects access universal mobile telecommunications system UMTS;

When C2. user terminal judges its standby mode in Low Power Mode and does not initiate or carry out real time business communication, and while judging the WLAN (wireless local area network) WLAN that current nothing satisfies condition, select access UMTS, otherwise select access WLAN according to the alternative condition of setting;

C3. user terminal judges its standby mode in normal mode and does not initiate or carry out real time business when communication, and judges currently while there is no accessible WLAN, selects access UMTS, otherwise selects access network according to the alternative condition of setting.

2. the method for claim 1, is characterized in that, in described steps A, the concrete grammar of three kinds of standby modes of definition user terminal is that the decision condition of three kinds of standby modes of setting, is specially:

When user terminal translational speed surpasses the speed threshold value of setting, be judged to be motor pattern;

When user terminal electric weight lower than set electric weight threshold value time, be judged to be Low Power Mode;

When user terminal in static or translational speed lower than the threshold value of setting, and electric weight higher than set electric weight threshold value time, be judged to be normal mode.

3. method as claimed in claim 2, is characterized in that, the speed threshold value of described setting is 1.5m/s; The electric weight threshold value of described setting is 20% of the total electric weight of described user terminal battery.

4. method as claimed in claim 1 or 2, is characterized in that, described communication quality refers to network delay and error rate requirement.

5. method as claimed in claim 2, is characterized in that, described step C2 specifically comprises the steps:

When user terminal judges its standby mode in Low Power Mode and do not initiate or carry out real time business communication, according to following Rule of judgment, select access network:

Judge currently while there is no accessible WLAN, select access UMTS;

When the bandwidth that judges the accessible WLAN of current existence and current accessible WLAN does not meet the bandwidth threshold value of setting, select access UMTS;

Judge when WLAN of current existence and its bandwidth meet the bandwidth threshold value of setting, select this WLAN of access;

While judging the current WLAN that has a bandwidth threshold value that a plurality of bandwidth meet to set, the WLAN of the gravitation maximum that the gravitation judgement formula that selective basis is set calculates accesses.

6. method as claimed in claim 2, is characterized in that, described step C3 specifically comprises the steps:

When user terminal judges its standby mode in normal mode and do not initiate or carry out real time business communication, according to following Rule of judgment, select access network:

Judge currently while there is no accessible WLAN, select access UMTS;

When the bandwidth that judges the accessible WLAN of current existence and current accessible WLAN does not meet the bandwidth threshold value of setting, select access UMTS;

While judging the current WLAN that has a bandwidth threshold value that bandwidth meet to set, the network that meets the gravitation maximum that gravitation judgement formula that in the WLAN of the bandwidth threshold value of setting and UMTS, selective basis is set calculates in described bandwidth accesses.

7. the method as described in claim 5 or 6, is characterized in that, the signal strength threshold value of described setting is-90dbm; Described bandwidth threshold value is 9.6kbps.

8. the method as described in claim 5 or 6, is characterized in that, the gravitation judgement formula of described setting is:

$F_N=k\frac{M_N{M}_T}{R^2},$

Wherein, F _nfor the gravitation of access network N to user terminal T, M _nfor the quality of access network N, M _tfor the quality of user terminal T, R be user terminal T to base station or the distance of Network Access Point, k is invariant;

M _ncomputing formula be: $M_N=B_N+\frac{1}{D_N}+\frac{1}{E_N}+\frac{1}{C_N},$

Wherein, B _n, D _n, E _n, C _nthe network availability bandwidth B of the access network N detecting while being respectively switching judging in step C _n, end-to-end delay D _n, error rate E _nwith Internet utilization fee C _nnormalized value;

The quantity of the access network that current participation is calculated is m, B _ncomputing formula be:

D _ncomputing formula be: $D_N=\frac{\frac{1}{D_n}}{\max (\frac{1}{D_1},\frac{1}{D_2},...,\frac{1}{D_m})},$

E _ncomputing formula be: $E_N=\frac{\frac{1}{E_n}}{\max (\frac{1}{E_1},\frac{1}{E_2},...,\frac{1}{E_m})},$

C _ncomputing formula be: $C_N=\frac{\frac{1}{C_n}}{\max (\frac{1}{C_1},\frac{1}{C_2},...,\frac{1}{C_m})}.$

9. method as claimed in claim 8, is characterized in that, described k is invariant 1; Described M _tfor invariant; Described R is that user terminal T is to base station or the actual range D of network N access point and map network covering radius R _nratio, its computing formula is:

$R=\frac{D}{R_N}.$

10. a user terminal, implements the method as described in claim 1-9 any one, it is characterized in that, comprising:

Standby mode definition module, for judging that the user terminal at place is current in which kind of standby mode, described standby mode specifically comprises motor pattern, normal mode and Low Power Mode, when user terminal translational speed surpasses the speed threshold value of setting, is judged to be motor pattern; When user terminal electric weight lower than set electric weight threshold value time, be judged to be Low Power Mode; When user terminal in static or translational speed lower than the threshold value of setting, and electric weight higher than set electric weight threshold value time, be judged to be normal mode;

Switch detection module, for detecting according to the signal intelligence of place user terminal and determining whether to want trigger network to switch, and notice is switched selection module; Specifically for when user terminal does not carry out any communication, when standby mode changes, trigger user terminal the signal strength signal intensity of current access network is detected, if the signal strength signal intensity of current access network detected lower than the signal strength threshold value of setting, notice is switched the switching of selection module trigger network; When user terminal will initiating communication, if current access network detected, cannot meet the required communication quality of its business, notice is switched and is selected module trigger network to switch; When user terminal is in communication process, when current access network being detected and cannot meet the required communication quality of its business, notice is switched and is selected module trigger network to switch;

Switch and select module, for after receiving the notice of switch detection module, according to the alternative condition switching and network access of setting; Specifically for the standby mode when obtain user terminal from standby mode definition module, when motor pattern and/or user terminal will carry out or carry out real time business communication, select access universal mobile telecommunications system UMTS; When the standby mode that obtains user terminal from standby mode definition module is in Low Power Mode and when not initiating or carrying out real time business communication, and while judging the WLAN (wireless local area network) WLAN that current nothing satisfies condition, select access UMTS, otherwise select access WLAN according to the alternative condition of setting; When the standby mode that obtains user terminal from standby mode definition module is in normal mode and do not initiate or carry out real time business communication, and judge current while there is no accessible WLAN, select access UMTS, otherwise select access network according to the alternative condition of setting.