CN101646211A - Vertical-switching control method based on frequency spectrum mapping - Google Patents

Abstract

The invention relates to a vertical-switching control method based on frequency spectrum mapping; radio resources occupied in a CDMA system by a user and QoS requirements thereof are mapped into mapping spectral bandwidth, and then radio resources occupied in a WLAN system by a user and QoS requirements thereof are mapped into mapping spectral bandwidth, and then WLAN/CDMA united resource space isconstructed, service-quality revenue function is defined by the quantity of obtained mapping spectrum on the space, next, a vertical-switching process is controlled, the control target is to lead each calling to have highest total revenue within a duration time. The QoS of the user and the occupied resources in WLAN and CDMA network can be mapped into the mapping spectral bandwidth in a unified way, the mapping spectral bandwidth is used to define the vertical-switching revenue function, and the target of the highest revenue function is used to control switching, thereby improving the utilization efficiency of radio resources while ensuring the service quality of the user.

Description

Vertical-switching control method based on the frequency spectrum mapping

Technical field

The present invention relates to a kind of vertical-switching control method, belong to communication technical field based on the frequency spectrum mapping.

Background technology

Following wireless access system can merge the Radio Access Network of multiple isomery on IP backbone.The Radio Access Network of isomery refers to and adopts different wireless technology systems to carry out user's wireless access.Different wireless technology systems comprises WCDMA system, WLAN system etc.One of key issue that the heterogeneous wireless network convergence system faces is exactly to support user's (or connection) promptly keeping in the switching between heterogeneous network to be transformed into another kind of wireless network from a kind of wireless network when the user connects.This conversion is referred to as vertical switching.Conversion between the different networks must be controlled someway in employing, and the purpose of changing between Control Network is when guaranteeing QoS of customer, and improves the efficient that Radio Resource utilizes as far as possible.

In the vertical-switching control method that has existed, all exist two basic problems: at first, do not consider the unified expression and the quantification of heterogeneous network resource.In existing method for handover control, all with the usable spectrum bandwidth of heterogeneous networks as the user or call out the key parameter of considering when selecting network, yet in CDMA net and WLAN net, the Radio Resource of CU is not expressed with spectral bandwidth, in above-mentioned two networks, the user occupies the whole network bandwidth in the mode of spread spectrum or competition, and available resources are expressed and reserved to the form that therefore is difficult to direct dedicated bandwidth for switching the user.From this aspect, existing method for handover control generally with bandwidth as parameter, and do not provide the corresponding relation of bandwidth and each Internet resources, therefore too shielded the resource characteristics of physical layer and made that method for handover control is difficult to use.Secondly existing method for handover control is only considered with current network state to lack in call duration calling out the global optimization of switching income as handover triggering condition.

We think that Radio Resource according to different dividing mode (in fact also being multi-access mode), has different expression in different systems.Can be expressed as channel (TDMA), code channel (CDMA) or medium (WLAN) as it.Yet because transmission medium all is unified electromagnetic wave, therefore above-mentioned resource is the expression of electromagnetic spectrum when cutting apart in the different orthogonal space.Can be mapped as taking to taking of above-mentioned resource in essence to frequency spectrum.

Summary of the invention

Technical problem: the purpose of this invention is to provide a kind of vertical-switching control method based on the frequency spectrum mapping, the resource that the user takies in said system is unified with the mapping frequency spectrum designation, unified reference when being switched between heterogeneous network, the user is arranged on resource, thereby when guaranteeing QoS of customer, improve wireless resource utility efficiency.

Technical scheme: the present invention earlier is mapped as the mapping spectral bandwidth with Radio Resource and the qos requirement thereof that the user takies when the cdma system, Radio Resource and the qos requirement thereof that the user is taken when the wlan system is mapped as the mapping spectral bandwidth again, then construct WLAN/CDMA federated resource space, how much with acquisition mapping frequency spectrum on this space is switch call definition service quality revenue function, then control vertical handover procedure, the target of control is to make each call out total revenue maximum in the duration.

1.CDMA the map bandwidth of CU in the network

In cdma system, the signal noise ratio of quality of services for users (QoS) and received signal is corresponding, and this corresponding relation is relevant with system modulation mode and signal processing mode, and given quality of service requirement is also with regard to given signal noise ratio thresholding.The signal noise ratio of receiver received signal is function (the different cdma system of bit rate, spreading gain, channel parameter and the overall system bandwidth of signal number, each signal power of arriving receiver, each signal, the expression of signal noise ratio is different, in many code systems, overall system bandwidth can be expressed as the long-pending of chip speed and spreading gain, so overall system bandwidth can not occur in the signal noise ratio expression formula).When the multi-user, this function has constituted the equation with many unknowns group.For certain variable vector (as vector power), exist the condition of separating to be subjected to the common restriction of overall system bandwidth, number of users and signal noise ratio, we can find each user's the weight of signal noise ratio in the mapping spectral bandwidth from this restricting relation, promptly find the mapping relations of service quality to spectral bandwidth.

2.WLAN user's mapping spectral bandwidth in the network

As in time division multiple access (TDMA), expressing Radio Resource with time slot, in wlan system, resource was expressed by the channel occupancy time, yet a user data package is successfully transmitted needed channel time and is not equal to the interchannel that takies when packet really transmits, and this is different with TDMA.Because will wait for channel idle a period of time before the data packet transmission, and transmitted and also do not meant that certain success, therefore this paper time of successfully transmitting the required usefulness of packet from the research wlan network sets about analyzing resource, and and then find out relation between it and the frequency spectrum resource, finally draw the mapping spectral bandwidth and express.

This method is mapped as the mapping spectral bandwidth with quality of services for users QoS and the resource unification that takies thereof in WLAN and cdma network, with the vertical revenue function that switches of mapping spectral bandwidth definition, be target to the maximum with revenue function and control switching; Specifically comprise: the resource that the user takies in WLAN and cdma network is to the mapping method of mapping spectral bandwidth; Vertical switching revenue function and maximization control changing method thereof with the definition of mapping spectral bandwidth;

The first step is calculated the mapping frequency spectrum of user in the multi-code cdma system:

${\∂}_m=\frac{(1+{2v}^2)C_m{R}_{m}W}{(1+2v^2)C_m{R}_m+\frac{3}{2}G[1-F\left(G\right)R_m]}$

Wherein G is a spreading gain, and F (G) depends on covariance function relevant with attenuation process in the WSSUS channel, and parameter v is the transmission coefficient of fading channel, C _mBe a Φ _mService class is called out used code channel number, R _mBe Φ _mProfessional required minimum signal noise interference, W is a system bandwidth;

Second step was calculated the mapping frequency spectrum of user in wlan system:

${\mathrm{\β}}_n={\mathrm{\λ}}_n\left(\frac{2-p_n}{2-2p_n}\right)P_S$

λ _mBe packet generation rate, p _nBe φ _nThe data packet collision probability of category node, P _SIt is the packet size;

In the 3rd step, structuring user's is obtainable normalized mapping spectral bandwidth space B in CDMA and wlan network ¹And B ²Can be expressed as respectively:

$B^1=\left\{\begin{array}{ccccc}0,& 1,& 2,& ...,& \left[\frac{W}{{\∂}_1}\right]\end{array}\right\}$ $B^2=\left\{\begin{array}{ccccc}0,& 1,& 2,& ...,& \left[\frac{B}{{\mathrm{\β}}_1}\right]\end{array}\right\}$

1 is a mapping spectral bandwidth unit in the formula, at B ¹Representative be that can to obtain to shine upon spectral bandwidth be one

At B ²In representative be that can to obtain to shine upon spectral bandwidth be a β ₁, [] expression rounds;

The 4th step is with mapping spectral bandwidth definition revenue function

$r(s,a)=\left\{\begin{array}{cc}f(s,a)-\mathrm{\μ}(s,a)-1,& i\≠j\\ f(s,a)-\mathrm{\μ}(s,a),& i=j\end{array}\right.$

In the formula: $f(s,a)=f_b(s,a)=\left\{\begin{array}{cc}1,& b_a\&GreaterEqual;U_B\\ (b_a-L_B)/(U_B-L_B),& L_B<b_a<U_B\\ 0,& b_a\&le;L_B\end{array}\right.$ Be the link income, L _BAnd U _BBe respectively needed minimum of user and maximum mapping spectral bandwidth;

$\mathrm{\&mu;}(s,a)=\left\{\begin{array}{cc}{b}_a{M}_a& ,L_B<b_a<U_B\\ U_B{M}_a& ,b_a\&GreaterEqual;U_B\end{array}\right.$ Be network billing function, M _aThe price of the unit mapping spectral bandwidth of a action back in network has as a result been taked in expression,

The 5th step. switch with the maximum next controlled switching controls of income, make $v^{\mathrm{\&pi;}}\left(s\right)=E_{\mathrm{\&pi;}}^s\left[E_N\right\{\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}r(s_t,A\left(s_t\right))\left\}\right]$ Maximum;

In the formula: v ^π(s) be given initial condition s (the current state s when also being t=1 ₁) expectation total revenue during from t=1 usage policy π; s _tExpression t current state constantly, A (s _t) be illustrated in s _tThe action of choosing under the state, E _NFor on connect hours N, total revenue being asked expectation, E _π ^sFor to given initial condition s, on the tactful π that selects, total revenue is asked expectation;

VIA realizes v with the value iterative algorithm ^π(s) maximum, process prescription is as follows:

1) right $\&ForAll;s\&Element;S$ , v is established in initialization ⁰(s)=0, iterations k=0, ε＞0

2), calculate to each state s $v^{k+1}\left(s\right)=\underset{a\&Element;A}{\max }\{r(s,a)+\underset{s^{\&prime;}\&Element;S}{\mathrm{\&Sigma;}}\mathrm{\&lambda;P}[s^{\&prime;}|s,a]v^k\left(s^{\&prime;}\right)\}$

3) if || v ^K+1-v ^k||＜ε (1-λ)/2 λ, jumped to for the 4th step, otherwise make k=k+1, returned for second step

4) obtain best static policies

$\mathrm{\&delta;}\left(s\right)=\arg \underset{a\&Element;A}{\max }\{r(s,a)+\underset{s^{\&prime;}\&Element;S}{\mathrm{\&Sigma;}}\mathrm{\&lambda;P}[s^{\&prime;}|s,a]v^{k+1}\left(s^{\&prime;}\right)\}$

In the above-mentioned formula, S represents the residing state of system, and a represents the behavior taked, and ε is an iteration step length, and the average of call duration is 1/1-λ; P (s ' | s, a) be illustrated under the condition that state s taked action a, etching system is in the probability of state s ' when next is made a strategic decision; A is an action space, promptly is the set of behavior a.

Beneficial effect: be expressed as map bandwidth by Radio Resource unification with heterogeneous system, solve the resource in the heterogeneous networks and unified expression problem, and then can define revenue function by map bandwidth, and having provided under the state of heterogeneous networks, how the user switches to obtain maximum total revenue.Therefore when guaranteeing QoS of customer, improved the Radio Resource utilization ratio.

Embodiment

One. at first consider the mapping of multi-service multi-code cdma system frequency spectrum

The first step: list Φ _mThe signal noise interference ratio of service class is as follows:

$r_m={[(\underset{j=1,j\&NotEqual;m}{\overset{M}{\mathrm{\&Sigma;}}}{C}_j{N}_j{P}_j+N_m{C}_m{P}_m-C_m{P}_m)\frac{1+2v^2}{\frac{3}{2}{\mathrm{GP}}_m}+F\left(G\right)+\frac{N_0}{E_{\mathrm{bm}}}]}^{-1}$ m＝1，…，M(1)

Here P _mBe Φ _mService class is called out the received power at the every code channel of base station end, and G is a spreading gain, N _mBe Φ _mThe number of calling out in the service class, F (G) depends on covariance function relevant with attenuation process in the WSSUS channel, parameter v is the transmission coefficient of fading channel, N ₀Be the spectrum density of Gaussian noise, E _BmBe energy per information bit, it can be expressed as E _Bm=P _m/ B.C _mBe a Φ _mService class is called out used code channel number, second step: separate above-mentioned equation group and can get minimum power

$P_m=\frac{\frac{(1+2v^2)C_m{R}_{m}W}{(1+2v^2)C_m{R}_m+\frac{3}{2}G[1-F\left(G\right)R_m]}\frac{\frac{3}{2}{N}_0\mathrm{BG}}{(1+2v^2)}}{(W-\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{N}_j\frac{(1+{2v}^2)C_j{R}_{j}W}{(1+2v^2)C_j{R}_j+\frac{3}{2}G[1-F\left(G\right)R_j]})C_m}$

R wherein _mBe Φ _mProfessional required minimum signal noise interference .W is a system bandwidth.

The 3rd step was separated P from power _mThe necessary and sufficient condition that exists draws the mapping relations of Radio Resource (code channel number), user's qos requirement (error rate requirement) and the frequency spectrum of CU:

${\&PartialD;}_m=\frac{(1+{2v}^2)C_m{R}_{m}W}{(1+2v^2)C_m{R}_m+\frac{3}{2}G[1-F\left(G\right)R_m]}$

Relation between every CU frequency spectrum and the total frequency spectrum:

$\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{\&PartialD;}_j{N}_j<W$

Clearly, in fact above-mentioned inequality " has converted " the CDMA multi-access mode to FDMA mode that different user occupies the different mappings bandwidth.In this way, the reservation of Radio Resource can be expressed with frequency spectrum is unified.

Two then carry out the frequency spectrum mapping of wlan system ground

Φ _mA packet of class user's generation can be through the not busy detection of channel busy, transmission wait and possible repeatedly collision until successfully send.Our definition is " equivalent busy channel time " during this period of time, uses T _mExpression.During this period of time, network has following situation and takes place: 1) the network free time, this user is in and surveys the stand-by period; 2) network busy, other users have successfully sent packet; 3) network busy, data bump; 4) network busy, this user successfully sends packet.It is as follows that the first step is calculated the average latency:

$\stackrel{\&OverBar;}{W_m}=\underset{k=1}{\overset{m_r+1}{\mathrm{\&Sigma;}}}{p}_m^{k-1}(1-p_m)\underset{n=1}{\overset{k}{\mathrm{\&Sigma;}}}\frac{{\mathrm{CW}}_m\left(n\right)-1}{2}$

CW _{M, min}Be Φ _mThe minimum competition window of class business is.m _rBe the maximum retransmit restriction.CW _m(k)=min (CW _{M, max}, 2 ^K-1CW _{M, min}), k=1 ... m _rThe+1st, Φ _mThe competition window of class packet when retransmitting for the k time. $p_m=1-{(1-\frac{{\mathrm{\&lambda;}}_m}{1-p_m})}^{N_m-1}\underset{n=1,n\&NotEqual;m}{\overset{S}{\mathrm{\&Pi;}}}{(1-\frac{{\mathrm{\&lambda;}}_n}{1-p_n})}^{N_n},$ M=1 ... S is Φ _mClass user's data bag collision probability

Second step was calculated other users' average transmitting time

At T _mIn time, except being investigated user, each Φ _mThe data packet number of class user's average generation is λ _mT _m(λ _mBe the packet generation rate).If system is in stable state, so at T _mIn time, the packet that each user produces should be sent out on statistics, and except being investigated the user, the total time that every other user expends in the whole system is: $(N_m-1){\mathrm{\&lambda;}}_m{T}_m{T}_S+T_m{T}_S{\mathrm{\&Sigma;}}_{n=1,n\&NotEqual;m}^S{N}_n{\mathrm{\&lambda;}}_n.$

The 3rd step was calculated mean collision time

Therefore at T _mIn time, the mean collision time of being investigated the user can be expressed as:

$\stackrel{\&OverBar;}{T_{c_m}}=T_s\underset{k=1}{\overset{m_r+1}{\mathrm{\&Sigma;}}}(k-1)p_m^{k-1}(1-p_m)$

p _mBe φ _mThe data packet collision probability of category node.At T _mIn time, other users of system because of the temporal summation that collision takies are $\frac{1}{2}[(1+(N_m-1){\mathrm{\&lambda;}}_m{T}_m)\stackrel{\&OverBar;}{T_{c_m}}+T_m{\mathrm{\&Sigma;}}_{n=1,n\&NotEqual;m}^S{N}_n{\mathrm{\&lambda;}}_n\stackrel{\&OverBar;}{T_{c_n}}].$

Equivalence busy channel time T _mBe above-mentioned three time sums.

The frequency spectrum mapping of the 4th step

For Φ _mClass user, the equivalent busy channel time of successfully transmitting a packet is T _m, so the equivalent rate of data packet transmission is 1/T _mThe stable condition of wlan system is

That is:

${\mathrm{\&lambda;}}_m{T}_m=\frac{{\mathrm{\&lambda;}}_m(2T_S+2\stackrel{\&OverBar;}{W_m}+\stackrel{\&OverBar;}{T_{c_m}})}{2+{\mathrm{\&lambda;}}_m(2T_S+\stackrel{\&OverBar;}{T_{C_m}})-{\mathrm{\&Sigma;}}_{n=1}^S{N}_n{\mathrm{\&lambda;}}_n(2T_S+\stackrel{\&OverBar;}{T_{c_n}})}<1$

Put in order:

${\mathrm{\&Sigma;}}_{n=1}^S{N}_n{\mathrm{\&lambda;}}_n\left(\frac{2-p_n}{2-{2p}_n}\right)P_S<B$

p _nBe φ _nThe data packet collision probability of category node, P _SIt is the packet size.The 5th step drew the mapping relations of Radio Resource, user's qos requirement and the frequency spectrum of CU from the stable condition of above-mentioned wlan system:

${\mathrm{\&beta;}}_n={\mathrm{\&lambda;}}_n\left(\frac{2-p_n}{2-2p_n}\right)P_S$

Relation between every CU frequency spectrum and the total frequency spectrum is as follows:

${\mathrm{\&Sigma;}}_{n=1}^S{N}_n{\mathrm{\&beta;}}_n<B.$

Equally, in fact above-mentioned inequality " has converted " the statistics time division multiple access way to FDMA mode that different user occupies different spectral.In this way, the reservation of Radio Resource can be expressed with frequency spectrum is unified.

Three. switch the obtainable spectral bandwidth of user

The user the available mapping frequency spectrum of heterogeneous networks what, be that the user selects one of key factor of network.Switching the user can be expressed as this network total spectrum bandwidth in the available mapping spectral bandwidth of certain network and deduct the mapping spectral bandwidth that network Central Plains has the user to take.For the purpose of simplifying statement, consider to support in the network two class business: speech and data,

The mapping spectral bandwidth that each voice user takies in the expression cdma network,

Be the bandwidth that each data user takies in the cdma network, β ₁, β ₂Be respectively each speech and the shared bandwidth of data user in the wlan network.Switch user's obtaining in cdma network and shine upon spectral bandwidth $b_a=W-\underset{j=1}{\overset{2}{\mathrm{\&Sigma;}}}{\&PartialD;}_j{N}_j,$ Obtaining in WLAN shone upon spectral bandwidth $b_a=B-\underset{j=1}{\overset{2}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_j{N}_j,$ Because the user's order N in the network _jBecome when being, according to N _jDifference, switch user's obtainable maximum mapping spectral bandwidth in two networks and be respectively W and B, minimum is 0.

For Markovian decision process being introduced vertical switching controls, must be able to obtain to shine upon the spectral bandwidth discretization and express, so with

β ₁Be respectively radix to CDMA and wlan network obtain shine upon spectral bandwidth and carry out normalization.User's obtainable normalized mapping spectral bandwidth space B in CDMA and wlan network then ¹And B ²Can be expressed as respectively:

$B^1=\left\{\begin{array}{ccccc}0,& 1,& 2,& ...,& \left[\frac{W}{{\&PartialD;}_1}\right]\end{array}\right\}$ $B^2=\left\{\begin{array}{ccccc}0,& 1,& 2,& ...,& \left[\frac{B}{{\mathrm{\&beta;}}_1}\right]\end{array}\right\}$

1 is a mapping spectral bandwidth unit in the formula, at B ¹Representative be that can to obtain to shine upon spectral bandwidth be one

At B ²In representative be that can to obtain to shine upon spectral bandwidth be a β ₁, [] expression rounds.

Four. with the link maximum revenue is that target is carried out switching controls

First step definition revenue function; The link income has reflected the degree that user QoS is met, and is defined as:

$f(s,a)=f_b(s,a)=\left\{\begin{array}{cc}1,& b_a\&GreaterEqual;U_B\\ (b_a-L_B)/(U_B-L_B),& L_B<b_a<U_B\\ 0,& b_a\&le;L_B\end{array}\right.$

In the formula: L _BAnd U _BBe respectively needed minimum of user and maximum mapping spectral bandwidth.When network can obtain to shine upon spectral bandwidth greater than the required maximum mapping of connection spectral bandwidth, the link income was 1; In the time can obtaining to shine upon spectral bandwidth between user's minimum and greatest requirements, spectral bandwidth is linear to be increased the link income with obtaining to shine upon; Income is 0 in the time can obtaining to shine upon spectral bandwidth less than the required minimum mapping of connection spectral bandwidth.

In order to make the user select factum more reasoningly, the present invention adopts the mode that CU mapping spectral bandwidth is chargeed of pressing.Make M _aThe price of the unit mapping spectral bandwidth of a action back in network has as a result been taked in expression, and define grid charging function is:

$\mathrm{\&mu;}(s,a)=\left\{\begin{array}{cc}{b}_a{M}_a& ,L_B<b_a<U_B\\ U_B{M}_a& ,b_a\&GreaterEqual;U_B\end{array}\right.$

Then revenue function is

$r(s,a)=\left\{\begin{array}{cc}f(s,a)-\mathrm{\&mu;}(s,a)-1,& i\&NotEqual;j\\ f(s,a)-\mathrm{\&mu;}(s,a),& i=j\end{array}\right.$

Second step. obtain switching control strategy with the income maximum

Make v ^π(s) be given initial condition s (the current state s when also being t=1 ₁) expectation total revenue during from t=1 usage policy π, it can be expressed as

$v^{\mathrm{\&pi;}}\left(s\right)=E_{\mathrm{\&pi;}}^s\left[E_N\right\{\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}r(s_t,A\left(s_t\right))\left\}\right]$

In the formula: S _tExpression t current state constantly; A (s _t) be illustrated in s _tThe action of choosing under the state, i.e. switching behavior; E _NFor on connect hours N, total revenue being asked expectation; E _π ^sFor to given initial condition s, on the tactful π that selects, total revenue is asked expectation.

Our purpose requires out to make v exactly ^π(s) Zui Da switchover policy.

The present invention realizes this goal with VIA (value iterative algorithm).

Algorithmic procedure is described below:

1) right $\&ForAll;s\&Element;S,$ V is established in initialization ⁰(s)=0, iterations k=0, ε＞0

2), calculate to each state s $v^{k+1}\left(s\right)=\underset{a\&Element;A}{\max }\{r(s,a)+\underset{s^{\&prime;}\&Element;S}{\mathrm{\&Sigma;}}\mathrm{\&lambda;P}[s^{\&prime;}|s,a]v^k\left(s^{\&prime;}\right)\}$

3) if || v ^K+1-v ^k||＜ε (1-λ)/2 λ, jumped to for the 4th step, otherwise make k=k+1, returned for second step

4) obtain best static policies

$\mathrm{\&delta;}\left(s\right)=\arg \underset{a\&Element;A}{\max }\{r(s,a)+\underset{s^{\&prime;}\&Element;S}{\mathrm{\&Sigma;}}\mathrm{\&lambda;P}[s^{\&prime;}|s,a]v^{k+1}\left(s^{\&prime;}\right)\}$

Claims (1)

1. vertical-switching control method based on frequency spectrum mapping, it is characterized in that this method is mapped as the mapping spectral bandwidth with quality of services for users QoS and the resource unification that takies thereof in WLAN and cdma network, with the vertical revenue function that switches of mapping spectral bandwidth definition, be target to the maximum with revenue function and control switching; Specifically comprise: the resource that the user takies in WLAN and cdma network is to the mapping method of mapping spectral bandwidth; Vertical switching revenue function and maximization control changing method thereof with the definition of mapping spectral bandwidth;

The first step is calculated the mapping frequency spectrum of user in the multi-code cdma system:

${\&PartialD;}_m=\frac{(1+2v^2)C_m{R}_{m}W}{(1+2v^2)C_m{R}_m+\frac{3}{2}G[1-F\left(G\right)R_m]}$

Wherein G is a spreading gain, and F (G) depends on covariance function relevant with attenuation process in the WSSUS channel, and parameter v is the transmission coefficient of fading channel, C _mBe a Φ _mService class is called out used code channel number, R _mBe Φ _mProfessional required minimum signal noise interference, W is a system bandwidth;

Second step was calculated the mapping frequency spectrum of user in wlan system:

${\mathrm{\&beta;}}_n={\mathrm{\&lambda;}}_n\left(\frac{2-p_n}{2-2p_n}\right)P_S$

λ _mThe packet generation rate, p _nBe φ _nThe data packet collision probability of category node, P _SIt is the packet size;

In the 3rd step, structuring user's is obtainable normalized mapping spectral bandwidth space B in CDMA and wlan network ¹And B ²Can be expressed as respectively:

$B^1=\left\{\begin{array}{ccccc}0,& 1,& 2,& ...,& \left[\frac{W}{{\&PartialD;}_1}\right]\end{array}\right\}$ $B^2=\left\{\begin{array}{ccccc}0,& 1,& 2,& ...,& \left[\frac{B}{{\mathrm{\&beta;}}_1}\right]\end{array}\right\}$

1 is a mapping spectral bandwidth unit in the formula, at B ¹Representative be that can to obtain to shine upon spectral bandwidth be one

At B ²In representative be that can to obtain to shine upon spectral bandwidth be a β ₁, [] expression rounds;

The 4th step is with mapping spectral bandwidth definition revenue function

$r(s,a)=\left\{\begin{array}{cc}f(s,a)-\mathrm{\&mu;}(s,a)-1,& i\&NotEqual;j\\ f(s,a)-\mathrm{\&mu;}(s,a),& i=j\end{array}\right.$

In the formula: $f(s,a)=f_b(s,a)=\left\{\begin{array}{cc}1,& b_a\&GreaterEqual;U_B\\ (b_a-L_B)/(U_B-L_B),& L_B<b_a<U_B\\ 0,& b_a\&le;L_B\end{array}\right.$

Be the link income, L _BAnd U _BBe respectively needed minimum of user and maximum mapping spectral bandwidth; $\mathrm{\&mu;}(s,a)=\left\{\begin{array}{cc}{b}_a{M}_a,& L_B<b_a<U_B\\ U_B{M}_a,& b_a\&GreaterEqual;U_B\end{array}\right.$ Be network billing function, M _aThe price of the unit mapping spectral bandwidth of a action back in network has as a result been taked in expression,

The 5th step. with the maximum next controlled switching of income

Control is switched, and makes $v^{\mathrm{\&pi;}}\left(s\right)=E_{\mathrm{\&pi;}}^s\left[E_N\right\{\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}r(s_t,A\left(s_t\right))\left\}\right]$ Maximum;

In the formula: v ^π(s) be given initial condition s (the current state s when also being t=1 ₁) expectation total revenue during from t=1 usage policy π; s _tExpression t current state constantly, A (s _t) be illustrated in s _tThe action of choosing under the state, E _NFor on connect hours N, total revenue being asked expectation, E _π ^sFor to given initial condition s, on the tactful π that selects, total revenue is asked expectation;

VIA realizes v with the value iterative algorithm ^π(s) maximum, process prescription is as follows:

1) right $\&ForAll;s\&Element;S,$ V is established in initialization ⁰(s)=0, iterations k=0, ε＞0

2), calculate to each state s $v^{k+1}\left(s\right)=\underset{a\&Element;A}{\max }\{r(s,a)+\underset{s^{\&prime;}\&Element;S}{\mathrm{\&Sigma;}}\mathrm{\&lambda;P}[s^{\&prime;}|s,a]v^k\left(s^{\&prime;}\right)\}$

3) if ‖ is v ^K+1-v ^k‖＜ε (1-λ)/2 λ jumped to for the 4th step, otherwise makes k=k+1, returned for second step

4) obtain best static policies

$\mathrm{\&delta;}\left(s\right)=\arg \underset{a\&Element;A}{\max }\{r(s,a)+\underset{s^{\&prime;}\&Element;S}{\mathrm{\&Sigma;}}\mathrm{\&lambda;P}[s^{\&prime;}|s,a]v^{k+1}\left(s^{\&prime;}\right)\}$

In the above-mentioned formula, S represents the residing state of system, and a represents the behavior taked, and ε is an iteration step length, and the average of call duration is 1/1-λ; P (s ' | s, a) be illustrated under the condition that state s taked action a, etching system is in the probability of state s ' when next is made a strategic decision; A is an action space, promptly is the set of behavior a.