CN104869594A - Network selection method considering service quality and network load in heterogeneous network - Google Patents

Abstract

The invention discloses a network selection method considering service quality and network load in a heterogeneous network. Reasonable network selection is made through building of a utility function. The utility function consists of user QoS (Quality of Service) satisfaction, a channel gain and user cost. In the utility function, the QoS demands of different businesses are considered, so that differentiated service is realized; and meanwhile, each part in the utility function is weighted according to user preferences, so that the user satisfaction is enhanced. Moreover, channel state information is utilized, and the network load condition is considered on the aspect of the cost part of the utility function, so that the situation of paralysis of a certain network due to over-high load is avoided as much as possible, and the wireless resource utilization ratio is increased.

Description

The network selecting method of service quality and offered load is considered in a kind of heterogeneous network

Technical field

The invention belongs to the network selecting method field of wireless communication system, particularly relate to the network selecting method considering service quality and offered load in a kind of heterogeneous network.

Background technology

Along with the fast development of wireless communication technology, various wireless access technology continues to bring out.Often kind of wireless access technology has respective feature.Such as LTE cellular system has two-forty, extensively covers, but lower deployment cost is higher; WLAN has high bandwidth, covers among a small circle, and cost is low, effectively can alleviate the communications burden of hot spot region.Therefore, different access technologies combined, be built into heterogeneous network, give full play to the advantage of various network, for user provides more good service, this becomes the inexorable trend of future wireless system development.

Meanwhile, present user traffic requires to improve constantly, and mobile communication subscriber amount constantly increases, and various multimedia application constantly occurs.But different business has different QoS (Quality ofService, service quality) demands, therefore need to consider differentiated service.

In addition, each user is different with the pursuit preference of cost to service quality.User can be divided into golden user, silver-colored user and copper user accordingly.Gold user pursues high-performance and does not mind the cost paid; Copper user pursues minimum cost under the prerequisite meeting minimum QoS demand; Silver user is in the type in the middle of golden user and copper user, has both pursued performance and has also pursued low cost.

In heterogeneous network, in order to ensure the service quality of user, to different business realizing differentiated services, consider the preference of user, it is reach this object key method that network is selected simultaneously.But in existing Research Literature, great majority well do not consider the multiple factors under heterogeneous network, often only considered the factor of a wherein part.Or the network selection policies proposed can not accurately utilize channel condition information and network load information etc., and cause load imbalance, resource utilization is not high.

Summary of the invention

For above-mentioned defect or deficiency, the object of the present invention is to provide the network selecting method considering service quality and offered load in a kind of heterogeneous network.

For reaching above object, technical scheme of the present invention is:

Comprise step:

1) the QoS satisfaction of each Network Capture service rate;

2) channel gain of each network is obtained;

3) obtain according to the rate value of offered load, expenses standard and charge the cost value that user pays; Described expenses standard is the amount of money that offered load and user's request network speed carry out that toll level divides the every bit charge carried out; The rate value of described charge is for the speed more than QoS satisfaction demand;

4) according to the preference of user, respectively the relation of QoS satisfaction, channel gain and cost value are weighted, obtain utility function, and utility function normalization is calculated, obtain normalization utility function value;

5) user selects the network having maximum normalization utility function value, and this network selects the user having maximum utility functional value to access;

6) step 1 is repeated) to step 5), until all users all access network or inadequate resources.

2, consider the network selecting method of service quality and offered load in heterogeneous network according to claim 1, it is characterized in that, described utility function computing formula is:

Utility function=QoS satisfaction+channel gain-cost value.

Described business comprises speech business and stream business.

Described step 1) specifically comprise: by the QoS characteristic of analyzing speech business with stream business, draw the relation of speed and QoS satisfaction, formula is described as:

A), for speech business:

$f[\mathrm{\δ}\left(n\right),R_m\left(n\right)]=\mathrm{\δ}\left(n\right)\·u(R_m\left(n\right)-R_{\min }^I)$

Wherein, $u\left(R\right)=\left\{\begin{array}{c}1,R\&GreaterEqual;0\\ 0,R<0\end{array}\right.$

In above formula, f [δ (n), R _m(n)] represent QoS satisfaction, δ (n) is Dynamic gene, for step function, R _mn () is the speed that network n is supplied to user m, it is the minimum speed limit demand of speech business;

B), for stream business:

f[δ(n),R _m(n)]＝δ(n)·ln(1+R _m(n))。

Described step 2) channel gain formula is:

$g\left(R_m\left(n\right)\right)=\frac{R_m\left(n\right)-R_{\min }^{\mathrm{sv}}}{R_{\min }^{\mathrm{sv}}}$

In formula:

_g(R _m(n))---channel gain;

Sv---{ I, S}, I represent speech business, and S flows business to meet sv ∈;

---meet $R_{\min }^{\mathrm{sv}}\&Element;\{R_{\min }^I,R_{\min }^S\}.$

For speech business, $R_{\min }^{\mathrm{sv}}=R_{\min }^I;$ For stream business, $R_{\min }^{\mathrm{sv}}=R_{\min }^S$ Wherein, $R_{\min }^{\mathrm{sv}}\&Element;\{R_{\min }^I,R_{\min }^S\}$

In above formula, g (R _m(n)) represent channel gain;

For speech business,

For stream business,

Described step 3) be specially:

3.1) network load factor is defined as:

$L\left(n\right)=1-\frac{{\mathrm{Rate}}_{\max }\left(n\right)}{C\left(n\right)}$

In formula:

L (n)---network load factor;

Rate _maxn ()---network n can be supplied to the speed of ideal communication channel user;

C (n)---the capacity of network n;

3.2) expenses standard is defined as:

In formula:

K (n)---expenses standard;

ρ (n)---regulatory factor;

---regulatory factor;

L (n)---network load factor;

3.3) speed of carrying out charging is:

For speech business, the speed of carrying out charging is needed to be the rate value of QoS demand

For stream business, need the speed R that the speed of carrying out charging provides for network _m(n) and larger rate requirement value between smaller, namely

3.4) cost value formula is expressed as follows:

In formula:

---cost value;

R ^sv---for speech business, for stream business, $R^{\mathrm{sv}}=\min (R_m\left(n\right),R_{\max }^S),$ Namely $R^{\mathrm{sv}}\&Element;\{R_{\min }^I,\min (R_m\left(n\right),R_{\max }^S)\}.$

Described step 4) obtain utility function be specially:

4.1) weight coefficient of each several part is represented respectively with following symbol:

η _qos(m)---the weight coefficient that QoS satisfaction is corresponding;

η _gain(m)---the weight coefficient that channel gain is corresponding;

η _cost(m)---the weight coefficient that user's cost is corresponding

Further,

η _qos(m)+η _gain(m)+η _cost(m)＝1；

4.2) computing formula of utility function is:

In formula:

---the utility function of network n user m business sv;

F [δ (n), R _m(n)]---QoS satisfaction;

G (R _m(n))---channel gain;

---cost value.

Described step 5) in utility function normalization calculate, obtain normalization utility function value and be specially:

The minimum QoS rate value of often kind of business substitutes into the computing formula of utility function:

For speech business:

For stream business:

Utility function be normalized by following formula:

$U_m^{\mathrm{sv}}\left(n\right)\&LeftArrow;\frac{U_m^{\mathrm{sv}}\left(n\right)-\mathrm{\&theta;}}{\left|\mathrm{\&theta;}\right|}$

In formula, θ ∈ { d ⁱ, d ^s.Compared with the prior art, beneficial effect of the present invention is:

The invention provides the network selecting method considering service quality and offered load in a kind of heterogeneous network, consider customer-side and network facet simultaneously., customer-side considers differentiated service and the user preference of different business; Network facet considers Network load status and channel condition information.By the normalized to Network load status and channel condition information, carry out the optimal selection of network, the result that the network being is selected makes user more satisfied, more decrease the cost of user simultaneously, improve resource utilization, each Internet resources are utilized more fully, has also better ensured the QoS demand of user simultaneously.

Accompanying drawing explanation

Fig. 1 is heterogeneous network communication scheme;

Fig. 2 is speech business QoS characteristic schematic diagram;

Fig. 3 is stream QoS of survice characteristic schematic diagram;

Fig. 4 is QLANS network selection scheme flow chart;

Fig. 5 is LTE speech business throughput simulation curve;

Fig. 6 is that LTE flows business throughput simulation curve;

Fig. 7 is LTE total throughout simulation curve;

Fig. 8 is WLAN single user throughput simulation curve;

Fig. 9 is WLAN total throughout simulation curve;

Figure 10 is total system throughput simulation curve;

Figure 11 is Network Load Balance factor simulation curve.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in detail.

First the system model communicated in heterogeneous network is described see Fig. 1.Consider the heterogeneous network having LTE and WLAN to set up.N is had in LTE _lindividual user, has N in WLAN _windividual user, has N _nindividual new user.The covering radius of LTE network is R _lTE, the covering radius of wlan network is R _wLAN.Original user in LTE and wlan network is uniformly distributed in corresponding region.N _nindividual new user is in the overlapping covered of LTE and WLAN, and random distribution.

Assuming that all user distributions keep static after a certain location.The channel model of LTE network is Rayleigh channel, wlan network due to covering radius little, its channel is thought desirable.

In order to realize differentiated service, consider two kinds of business, speech business and stream business.Speech business has minimum rate requirement, is designated as

Referring to the QoS characteristic of plain language sound business Fig. 2.

For speech business, the speed that can provide when network lower than time, business cannot be carried out, and now the QoS satisfaction of user is zero, the speed provided when network higher than now the QoS demand of user is met.Exceed part can not promote the QoS satisfaction of speech business.Because for speech business, the bottleneck of performance boost is information source.The speed of the information source of speech business can not exceed channel can provide higher speed can not change the traffic performance of information source.

Referring to the QoS characteristic of free flow business Fig. 3.

Stream business has two rate requirement, with when channel conditions is poor, the rate requirement of stream business is when channel conditions is better, the rate requirement of stream business is wherein, the speed that can provide when channel is higher, and the QoS satisfaction of user is higher, and the speed provided along with network constantly increases, and user QoS satisfaction increases degree and slowly diminishes.

In heterogeneous network, consider user's factor and network factors simultaneously, ensure the QoS demand of user and maximize wireless resource utility efficiency, the present invention proposes the network selecting method considering service quality and offered load in a kind of heterogeneous network.Detailed content is as follows:

By building utility function, consider customer-side and network facet simultaneously.Utility function is divided into 3 parts: QoS satisfaction part, channel gain component and user's cost part.

1) the QoS satisfaction of each Network Capture service rate;

Consider speech business and stream business.In order to ensure the QoS demand of miscellaneous service, first analyzing miscellaneous service QoS demand characteristic, drawing the relation of speed and QoS satisfaction.

(1) speech business

When network n is supplied to the speed R of voice user m _mn () is lower than minimum speed limit demand time, QoS satisfaction is 0, namely can not meet business primary demand;

Work as R _mn () is more than or equal to time, the QoS rate requirement of business is met, the experience that speed can not improve user if increase again, because now the transmission rate of channel is enough to the needs meeting business, service rate is limited to transmitting terminal speed instead of channel.

In speech business utility function, QoS satisfaction is expressed as:

$f[\mathrm{\&delta;}\left(n\right),R_m\left(n\right)]=\mathrm{\&delta;}\left(n\right)\&CenterDot;u(R_m\left(n\right)-R_{\min }^I)$

In formula:

F [δ (n), R _m(n)]---QoS extent function;

The satisfaction weight coefficient of δ (n)---network n;

---step function, namely $u\left(R\right)=\left\{\begin{array}{c}1,R\&GreaterEqual;0\\ 0,R<0\end{array}\right.;$

R _mn ()---network n can be supplied to the speed of user m;

---the minimum speed limit demand of speech business.

(2) business is flowed

Stream business has two rate requirement values.When channel conditions is bad, rate requirement value is when network condition is better, rate requirement value is

As the speed R that network provides _mn () is lower than lower rate threshold value time, business service stops, and the QoS satisfaction of business is 0;

The speed provided when network is not less than time, along with R _mn the increase of (), QoS satisfaction is higher.And R _mthe speed goes that when () increases n, QoS satisfaction improves is slow, this is because now the Minimum requirements of business is met, the demand improved speed is more and more less.

In stream service utility function, QoS satisfaction can be expressed as:

$f[\mathrm{\&delta;}\left(n\right),R_m\left(n\right)]=\mathrm{\&delta;}\left(n\right)\&CenterDot;\ln (1+R_m\left(n\right))\&CenterDot;u(R_m\left(n\right)-R_{\min }^S)$

In formula:

F [δ (n), R _m(n)]---QoS satisfaction;

The satisfaction weight coefficient of δ (n)---network n;

---step function, namely $u\left(R\right)=\left\{\begin{array}{c}1,R\&GreaterEqual;0\\ 0,R<0\end{array}\right..$

2) channel gain of each network is obtained

Channel conditions is better, then throughput is higher, and resource utilization is higher.Therefore, the channel conditions of network is better, makes channel gain component in utility function larger.With the speed R that network n provides _mn () represents channel yield value from the distance of minimum speed limit demand, be shown below:

$g\left(R_m\left(n\right)\right)=\frac{R_m\left(n\right)-R_{\min }^{\mathrm{sv}}}{R_{\min }^{\mathrm{sv}}}$

In formula:

G (R _m(n))---channel gain;

Sv---{ I, S}, represent speech business or stream business to meet sv ∈;

---meet $R_{\min }^{\mathrm{sv}}\&Element;\{R_{\min }^I,R_{\min }^S\}.$

For speech business, for stream business,

3) obtain according to the rate value of offered load, expenses standard and charge the cost value that user pays; Described expenses standard is the amount of money that offered load and user's request network speed carry out that toll level divides the every bit charge carried out; The rate value of described charge is for the speed more than QoS satisfaction demand

The cost that user pays is the smaller the better.The cost that user pays depends on that expenses standard and needs carry out the speed of charging.Network load status is considered in cost part, according to Network load status adjustment expenses standard: offered load L (n) is larger, in order to alleviate network pressure, arranges higher expenses standard, with the network that this guides user to select load light, thus avoid network congestion.Meanwhile, offered load is less, and expenses standard is lower, be then conducive to reducing user's cost.Therefore, cost part is relevant with the speed that needs carry out charging with offered load, expenses standard.

(1) network load factor

Offered load affects expenses standard.First ask network resource remaining situation, and then try to achieve Internet resources by situation about using, i.e. offered load.

The maximum rate Rate having ideal communication channel (not having channel fading) user is supplied to by estimation network n _maxn () represents residue of network organization resource, adopting the user of ideal communication channel to ask surplus resources to be interference in order to get rid of channel conditions, estimating surplus resources completely according to the resource utilization of network own.Then utilize the total capacity C (n) of network n to Rate _maxn () is normalized, just obtain resources left ratio, and then obtains the ratio that resource has been utilized, i.e. offered load.Based on above analysis, network load factor is defined as:

$L\left(n\right)=1-\frac{{\mathrm{Rate}}_{\max }\left(n\right)}{C\left(n\right)}$

In formula:

L (n)---network load factor;

Rate _maxn ()---network n can be supplied to the speed of ideal communication channel user;

C (n)---the capacity of network n.

In order to reflected load is balanced, the definition load balancing factor is the difference of maximum network load and minimal network load in heterogeneous network, is described below:

B _load＝L _max-L _min

In formula:

B _load---the load balancing factor;

L _max---maximum network load;

L _min---minimal network load.

B _loadless expression load distributes more balanced in heterogeneous network, more effectively can utilize resource.

(2) expenses standard

Expenses standard is defined as the amount of money of charging to every bit.In order to avoid network congestion, offered load is larger, and expenses standard is higher.The network that load is larger is more eager new access request to be transferred to other networks, thus more effectively realizes Network Load Balance, and therefore, and along with the increase of offered load, it is more and more faster that expenses standard improves.Based on this, the form of index is adopted to represent expenses standard.Based on above analysis, expenses standard is defined as:

In formula:

K (n)---expenses standard;

ρ (n)---regulatory factor;

---regulatory factor;

L (n)---network load factor.

(3) speed of charging

The part speed that user is only required to be QoS demand is paid a price, and the part speed exceeding QoS demand is that network gives user to make full use of resource, and user is not required to be this part and pays.Based on above analysis, the speed of carrying out charging is:

For speech business, the speed of carrying out charging is needed to be the rate value of QoS demand

For stream business, need the speed R that the speed of carrying out charging provides for network _m(n) and larger rate requirement value between smaller, namely

Cost part is formulated as follows:

In formula:

---cost value;

R ^sv---for speech business, for stream business, namely $R^{\mathrm{sv}}\&Element;\{R_{\min }^I,\min (R_m\left(n\right),R_{\max }^S)\};$

K (n)---expenses standard;

L (n)---network load factor.

4) user preference

According to the preference of user, respectively the relation of QoS satisfaction, channel gain and cost value are weighted, obtain utility function, and utility function normalization is calculated, obtain normalization utility function value.

Because different users has different preferences to service experience and the cost etc. paid, the preference of the result selected to make network more symbol user, when building utility function, the preference according to user arranges corresponding weight coefficient to the various piece in utility function.Which part user more lies in just arranges larger weighted value to this part.The weight coefficient of each several part is represented respectively with following symbol:

η _qos(m)---the weight coefficient that QoS satisfaction is corresponding;

η _gain(m)---the weight coefficient that channel gain is corresponding;

η _cost(m)---the weight coefficient that user's cost is corresponding.

Further,

η _qos(m)+η _gain(m)+η _cost(m)＝1

The above analysis, the computing formula of utility function is:

In formula:

---the utility function of network n user m business sv;

F [δ (n), R _m(n)]---QoS satisfaction;

G (R _m(n))---channel gain;

---cost value;

In order to compare the utility function of different business, need to be normalized utility function.

Utility function normalization:

In order to compare the utility function of different business, need to be normalized utility function.Normalized utility function reflects the distance of user satisfaction from basic QoS demand.The minimum QoS rate value of often kind of business is substituted into the computing formula of utility function:

For speech business:

For stream business:

Utility function be normalized by following formula:

$U_m^{\mathrm{sv}}\left(n\right)\&LeftArrow;\frac{U_m^{\mathrm{sv}}\left(n\right)-\mathrm{\&theta;}}{\left|\mathrm{\&theta;}\right|}$

In formula, θ ∈ { d ⁱ, d ^s.

5) user selects the network having maximum normalization utility function value, and this network selects the user having maximum utility functional value to access;

6) step 1 is repeated) to step 5), until all users all access network or inadequate resources.

Exemplary, composition graphs 4 illustrates the flow process that network is selected:

For reaching above object, technical scheme of the present invention is:

Introduce network selection procedures below.For convenience of setting forth, be defined as follows symbol.

N={n ₁, n ₂..., n _α---candidate network set;

---new user's set;

---select network n _iuser set.

User selects the network having maximum normalization utility function.Work as set after determining, network n _ifrom middle selection has the user m of maximum utility functional value ^*access:

$m^{*}=\arg \underset{m}{\max }{U}_m^{\mathrm{sv}}\left(n_i\right)$

For certain user, when multiple candidate network has equal maximum normalization utility function value simultaneously, in order to improve user satisfaction, user selects the network n that can provide maximum rate ^*access:

$n^{*}=\arg \underset{n}{\max }\left(R_m^{\mathrm{sv}}\left(n\right)\right)$

Consider that speech business priority is higher than stream business, for network n _i, when multiple user has maximum normalization utility function value simultaneously, prioritizing selection voice user access.

The network selection scheme ensured based on QoS in the heterogeneous network proposed is summarized as follows:

(1) initialization: η _qos(m), η _gain(m), η _cost(m), δ (n),

(2) R is estimated _m(n) and Rate _max(n);

(3) network n broadcasts R _m(n), Rate _max(n), C (n);

(4) also normalization utility function value is calculated

(5) each user selects the network having maximum normalization utility function value, produces

(6) network n _i(n _i∈ N) select the user having maximum normalization utility function value to access;

(7) repeat step 2-6 until all users all access network or inadequate resources, the QoS demand of new user can not be met.

The QLANS network selection scheme that the present invention proposes is the design based on utility function, considers business demand characteristic, channel conditions, user's cost, offered load and user preference simultaneously, and provides unitized utility function form for each network.Computation complexity is low, is easy to realize, and has good practicality.

Simulation result of the present invention and analysis.

Fig. 5 is LTE speech business throughput simulation curve figure.As can be seen from the figure, the QLANS scheme of proposition can guaranteed qos demand preferably.Along with the increase of the total number of users of network, under QLANS strategy, access LTE user slowly become many, single user throughput in LTE is slowly declined under the prerequisite meeting QoS demand.

Fig. 6 is that LTE flows business throughput simulation curve figure.As can be seen from the figure, along with the increase of total number of users under the QLANS scheme proposed, LTE flows the throughput degradation of business sheet user, but throughput is all greater than QoS Minimum requirements, has ensured the QoS of user preferably.

Fig. 7 is LTE network total throughout simulation curve figure.As we can see from the figure, the QLANS scheme of proposition can obtain larger throughput, more effectively make use of Radio Resource.

Fig. 8 is WLAN single user throughput simulation curve figure.As we can see from the figure, under QLANS scheme, the throughput of single user well ensure that the QoS demand of user, and because QLANS considers Network Load Balance, wlan network is made to be unlikely to load excessive, therefore the throughput of single user acquisition is higher than the throughput of contrast scheme, has better ensured the QoS demand of user.

Fig. 9 is WLAN total throughout simulation curve figure.As we can see from the figure, under QLANS scheme, WLAN total throughout is apparently higher than contrast scheme.This is because QLANS scheme effectively achieves load balancing between heterogeneous networks, such that wlan network resource is more effective to be utilized.

Figure 10 is the simulation curve figure of the total system throughput that LTE and WLAN is set up.As we can see from the figure, under QLANS scheme, total system throughput is apparently higher than contrast scheme.This is that performance significantly declines because load is excessive to avoid certain network because QLANS adopts load factor to adjust expenses standard in real time to realize network equilibrium.Provide enough the utilization ratio of Radio Resource.

Figure 11 is Network Load Balance factor simulation curve figure.Can clearly see from figure, the scheme of proposition effectively reduces the disequilibrium of offered load, and each Internet resources are utilized more fully, has also better ensured the QoS demand of user simultaneously.

Claims (8)

1. consider a network selecting method for service quality and offered load in heterogeneous network, it is characterized in that, comprise step:

1) the QoS satisfaction of each Network Capture service rate;

2) channel gain of each network is obtained;

3) obtain according to the rate value of offered load, expenses standard and charge the cost value that user pays; Described expenses standard is the amount of money that offered load and user's request network speed carry out that toll level divides the every bit charge carried out; The rate value of described charge is for the speed more than QoS satisfaction demand;

4) according to the preference of user, respectively the relation of QoS satisfaction, channel gain and cost value are weighted, obtain utility function, and utility function normalization is calculated, obtain normalization utility function value;

5) user selects the network having maximum normalization utility function value, and this network selects the user having maximum utility functional value to access;

6) step 1 is repeated) to step 5), until all users all access network or inadequate resources.

2. consider the network selecting method of service quality and offered load in heterogeneous network according to claim 1, it is characterized in that, described utility function computing formula is:

Utility function=QoS satisfaction+channel gain-cost value.

3. consider the network selecting method of service quality and offered load in heterogeneous network according to claim 1, it is characterized in that, described business comprises speech business and stream business.

4. in heterogeneous network according to claim 3, consider the network selecting method of service quality and offered load, it is characterized in that, described step 1) specifically comprise: by the QoS characteristic of analyzing speech business with stream business, draw the relation of speed and QoS satisfaction, formula is described as:

A), for speech business:

$f[\mathrm{\&delta;}\left(n\right),R_m\left(n\right)]=\mathrm{\&delta;}\left(n\right)\&CenterDot;u(R_m\left(n\right)-R_{\min }^I)$

Wherein, $u\left(R\right)=\left\{\begin{array}{c}1,R\&GreaterEqual;0\\ 0,R<0\end{array}\right.$

In above formula, f [δ (n), R _m(n)] represent QoS satisfaction, δ (n) is Dynamic gene, for step function, R _mn () is the speed that network n is supplied to user m, it is the minimum speed limit demand of speech business;

B), for stream business:

f[δ(n),R _m(n)]＝δ(n)·ln(1+R _m(n))。

5. consider the network selecting method of service quality and offered load in heterogeneous network according to claim 3, it is characterized in that, described step 2) channel gain formula is:

$g\left(R_m\left(n\right)\right)=\frac{R_m\left(n\right)-R_{\min }^{\mathrm{sv}}}{R_{\min }^{\mathrm{sv}}}$

In formula:

G (R _m(n))---channel gain;

Sv---{ I, S}, I represent speech business, and S flows business to meet sv ∈;

---meet $R_{\min }^{\mathrm{sv}}\&Element;\{R_{\min }^I,R_{\min }^S\};$

For speech business, $R_{\min }^{\mathrm{sv}}=R_{\min }^I;$ For stream business, $R_{\min }^{\mathrm{sv}}=R_{\min }^S$ Wherein, $R_{\min }^{\mathrm{sv}}\&Element;\{R_{\min }^I,R_{\min }^S\}$

In above formula, g (R _m(n)) represent channel gain;

For speech business,

For stream business,

6. consider the network selecting method of service quality and offered load in heterogeneous network according to claim 3, it is characterized in that, described step 3) be specially:

3.1) network load factor is defined as:

$L\left(n\right)=1-\frac{{\mathrm{Rate}}_{\max }\left(n\right)}{C\left(n\right)}$

In formula:

L (n)---network load factor;

Rate _maxn ()---network n can be supplied to the speed of ideal communication channel user;

C (n)---the capacity of network n;

3.2) expenses standard is defined as:

In formula:

K (n)---expenses standard;

ρ (n)---regulatory factor;

---regulatory factor;

L (n)---network load factor;

3.3) speed of carrying out charging is:

For speech business, the speed of carrying out charging is needed to be the rate value of QoS demand

For stream business, need the speed R that the speed of carrying out charging provides for network _m(n) and larger rate requirement value between smaller, namely

3.4) cost value formula is expressed as follows:

In formula:

---cost value;

R ^sv---for speech business, for stream business, namely $R^{\mathrm{sv}}\&Element;\{R_{\min }^I,\min (R_m\left(n\right),R_{\max }^S)\}.$

7. consider the network selecting method of service quality and offered load in heterogeneous network according to claim 6, it is characterized in that, described step 4) obtain utility function be specially:

4.1) weight coefficient of each several part is represented respectively with following symbol:

η _qos(m)---the weight coefficient that QoS satisfaction is corresponding;

η _gain(m)---the weight coefficient that channel gain is corresponding;

η _cost(m)---the weight coefficient that user's cost is corresponding

Further,

η _qos(m)+η _gain(m)+η _cost(m)＝1；

4.2) computing formula of utility function is:

In formula:

---the utility function of network n user m business sv;

F [δ (n), R _m(n)]---QoS satisfaction;

G (R _m(n))---channel gain;

---cost value.

8. consider the network selecting method of service quality and offered load in heterogeneous network according to claim 7, it is characterized in that, described step 5) in utility function normalization calculate, obtain normalization utility function value and be specially:

The minimum QoS rate value of often kind of business substitutes into the computing formula of utility function:

For speech business:

For stream business:

Utility function be normalized by following formula:

$U_m^{\mathrm{sv}}\left(n\right)\&LeftArrow;\frac{U_m^{\mathrm{sv}}\left(n\right)-\mathrm{\&theta;}}{\left|\mathrm{\&theta;}\right|}$

In formula, θ ∈ { d ⁱ, d ^s.