KR20050019945A - System and method for controlling resource causing mobility of terminal in a mobile communication system - Google Patents

Abstract

PURPOSE: A resource control system and a method in accordance with mobility of a terminal in a wireless communication system are provided to consider mobility of a wireless terminal, and to generate an admission-related cluster to admit or reject a call, thereby remarkably increasing a usage rate of wireless resources while reducing a handoff dropping probability. CONSTITUTION: An admission controller(220) receives mobility data(211), session information(212), and feature information(213) of requested traffic from a wireless terminal(210), receives bandwidth information for neighboring base stations, checks whether to admit a call by using remaining bandwidth information of a base station where the wireless terminal(210) is included, and checks whether to admit the requested traffic from resource information on the neighboring base stations to determine whether to assign the traffic. A radio resource assigning unit(240) assigns radio resources to the wireless terminal(210) according to the determined result.

Description

Resource control system and method according to mobility of terminal in wireless communication system {SYSTEM AND METHOD FOR CONTROLLING RESOURCE CAUSING MOBILITY OF TERMINAL IN A MOBILE COMMUNICATION SYSTEM}

The present invention relates to a system and method for resource control in a wireless communication system, and more particularly, to a system and method for resource control according to mobility of a terminal in a wireless communication system.

In general, a wireless communication system starts from a system mainly providing voice communication using a portable terminal. In such a voice communication-oriented wireless communication system, resources can be easily controlled. This is because voice communication requires constant Quality of Service (QoS) or radio resources that must be allocated. However, with the development of the third generation mobile communication system, systems that can provide not only voice communication but also data services and multimedia services are being developed one after another, and the commercialization of these systems has been reached.

In addition to the third generation mobile communication system described above, more types of data services and multimedia services will be provided in the forthcoming fourth generation mobile communication system. Therefore, various resources as described above may not be normally performed if resource allocation and call admission control (CAC) are made according to a simple load or load basis.

1 is a flow chart of admission control in accordance with the prior art of a voice only environment. Next, the process of the admission control flow according to the prior art of the voice-only environment will be described with reference to FIG. 1. When a new call is generated in the mobile communication system, the number of channels or the signal-to-interference ratio (SIR) value used in step 100 is calculated. In case of performing control according to the number of channels in step 110, it is checked whether the number of channels being used is smaller than the predetermined number (N), and when the value of the signal to interference ratio is used, the measured signal to interference ratio ( It is checked whether SIR _now is smaller than the signal-to-interference ratio SIR _TH of the predetermined threshold value. If the number of channels being used is smaller than the predetermined number, the process proceeds to step 120 to accept the new call. If the number of channels being used is not smaller than the predetermined number, the process proceeds to step 130 and rejects the new call. Similarly, in case of using the signal-to-interference ratio, if the current measured signal-to-interference ratio is smaller than the signal-to-interference ratio of the predetermined threshold, the process proceeds to step 120 to accept a new call, and the currently measured signal-to-interference ratio is the signal of the predetermined threshold. If it is not less than the interference ratio, proceed to step 130 to reject the new call.

In FIG. 1, N in step 110 becomes the maximum number of channels available in one cell. As such, the control according to the number of channels is very simple and easy to implement. However, this analysis is not appropriate for multimedia traffic. In other words, the multimedia service that has begun to emerge in the current third generation mobile communication system will appear as a mainstream service in the fourth generation mobile communication system in the future. Therefore, this method is obviously unreasonable since it assumes that data traffic and voice traffic have the same effect on the system. Therefore, the admission control method based on the number of channels or the signal-to-interference ratio, as described above, cannot be used in the case of multimedia traffic requiring different quality of service and data rates.

As a result, not only can not accurately control resources for the multimedia service that will emerge as a mainstream in the fourth generation mobile communication system, but also can not accurately determine the potential load, the system can not be used efficiently. In addition, since the mobility of the wireless terminal is not accurately considered, the quality of service or the service may be impossible.

Accordingly, an object of the present invention is to provide a system and method capable of performing efficient resource control in a wireless communication system.

Another object of the present invention is to provide a system and method capable of performing resource control according to a quality of service in a wireless communication system.

Another object of the present invention is to provide a system and method capable of performing resource control according to the amount of data transmitted in a wireless communication system.

Another object of the present invention is to provide a system and method for controlling resources in consideration of mobility of a terminal in a wireless communication system.

A system of the present invention for achieving the above objects, in a system for allocating resources on demand of a call from a wireless terminal in a wireless communication system comprising a mobile terminal having mobility and a base station capable of providing a multimedia traffic service, Receive mobility data and session information and feature information of the required traffic from the wireless terminal, receive bandwidth information of neighbor base stations of the base station including the wireless terminal, and receive the base station for the requested traffic from the wireless terminal. An admission control unit for checking whether the call is accepted using the remaining bandwidth information of the base station; and determining whether to allocate the traffic by checking whether the requested traffic is acceptable from the resource information of neighboring base stations; Radio resources The assignment includes a radio resource allocation.

The method may further include a scheduling queue for performing scheduling on the requested traffic and allocating resources according to the performed result when the approval controller determines the real time traffic.

The approval control unit,

A traffic classification unit for dividing and outputting traffic based on real-time or non-real-time traffic requested from the wireless terminal, and, in the case of the non-real-time traffic, according to the remaining bandwidth of the base station including the wireless terminal and the remaining bandwidth of the adjacent base station. The anticipated resource estimator may include an anticipated resource estimator that determines whether to approve the traffic.

In addition, the mobile station receives the mobility information, and is determined in consideration of resource conditions of neighboring base stations based on predetermined one-dimensional movement information, two-dimensional movement information, and three-dimensional movement information.

The approval control unit

When the traffic is allocated, the survival probability is calculated simultaneously with the estimation of the predicted resource to determine whether to allocate the traffic.

A method of the present invention for achieving the above objects is a method for allocating resources on demand of a call from a wireless terminal in a wireless communication system comprising a mobile terminal having mobility and a base station capable of providing a multimedia traffic service. When there is a request for traffic from the wireless terminal, classifying the traffic according to real time, and if a current resource of the base station including the wireless terminal can accommodate the requested traffic, the probability of progressing to neighboring base stations; Calculating a grant related cluster in consideration of resource status of neighboring base stations; and accepting the requested traffic when the sum of total bandwidths using the calculated value of the grant related cluster is less than or equal to the remaining bandwidth.

In addition, when the sum of the total bandwidths using the calculated value of the approval-related cluster is larger than the remaining bandwidth, the mobility change of the wireless terminal is calculated, the maximum value and the required quality of service according to the mobility change are calculated, and then the calculation. The method may further include allocating the traffic when the calculated mobility is less than the remaining bandwidth, and rejecting the required traffic when the calculated mobility is greater than the remaining bandwidth. .

In addition, the mobility change of the wireless terminal,

Based on the predetermined one-dimensional movement information, the two-dimensional movement information and the three-dimensional movement information, it is checked whether the resource state of adjacent base stations can accommodate the change in mobility.

Upon acceptance of the required traffic, the survival probability is calculated simultaneously with the estimation of the predicted resource to determine whether to allocate the traffic.

And if the current resource of the base station including the wireless terminal is unable to accommodate the requested traffic, rejecting the requested traffic.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings.

In addition, in the following description, there are many specific details such as specific messages or signals, which are provided to aid the overall understanding of the present invention, and it is understood that the present invention may be practiced without these specific details. It will be self-evident to those of ordinary knowledge. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First, the parts to be solved in the fourth generation wireless communication system will be described.

(1) Support for multimedia services in real time and non-real time

(2) frequent handoffs due to heavy system load and high mobility

(3) Inclusion of various multiple access technologies such as frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA)

(4) Providing a Complex Cellular System Structure With a Hierarchical Structure

Many matters other than those mentioned above should be considered, but only those mentioned above will be mentioned here. Admission control of calls to be provided in the fourth generation mobile communication system is mentioned in the second of the problems to be solved. Therefore, the admission control structure needs to deal with potential overload and prevent congestion by way of load factor. At the same time, in a hierarchical cellular system (HCS), prediction resource estimation based on the mobility of the user should also be considered. These details will be described below as the main features of the present invention.

The admission control structure to be described in the present invention is largely an admission control structure and an admission control algorithm to be added to the system in two parts. The admission control structure will describe the relationship between different functional entities of radio resource management, and the admission control algorithm is a mechanism in accordance with the control flow for admission control.

First, the admission control structure according to the present invention will be described. 2 is a block diagram of functional blocks for admission control according to a preferred embodiment of the present invention.

Referring to FIG. 2, a user mobility 211 information received from the user terminal 210, a session 212 information of the user terminal, and a traffic characteristic 213 of the user terminal are included. In this case, the user mobility information is not necessarily received from the user terminal 210, and may be received from the navigation system when using the navigation system (GPS). The user terminal and the navigation system may be used in parallel. Since any method can be used here, it will not be mentioned.

The session information is input to the traffic classification unit 211 of the admission control unit 220, the solid arrows show the flow of the session information. In addition, information according to radio resources such as user mobility 211 information and traffic feature 213 information is indicated by a dotted line. Thus, the dotted line indicates the improvisation of the traffic. The traffic classifier 211 receives the session 212 information and provides the estimated resource estimator 212 in the case of real-time traffic, and provides the scheduling queue 230 in the case of non-real-time traffic. The scheduling queue 230 may be configured as a memory for storing data necessary for the control of the admission controller. The expected resource estimating unit 212 estimates an expected resource according to the present invention to be described later, and determines whether to allocate resources according to the estimated resources. In addition, according to traffic and user mobility, the layer may be analyzed by the layer analyzer 213 provided in the predicted resource estimator 212 to be considered when determining whether to allocate resources. These contents are determined whether or not to allocate resources according to the content to be described later.

When the allocation of resources is determined by the approval controller 220, the resources are allocated to the mobile terminal by allocating radio resources to the Lydo resource allocating unit 240.

The mobility and call characteristics of the user are also related to the wireless environment. Therefore, authorization, scheduling, and resource allocation cannot be made solely at the request of the user. Therefore, the real-time and non-real-time calls are classified from the traffic classifier 211, and the required quality of service (QoS) is made in the traffic classifier 211, and the above items are also considered by the expected resource estimator 212. It will be.

Hereinafter, the main principle according to the present invention will be described.

1. Approval related cluster

The basic concept of an admission-related cluster is that all active0 mobile terminals have an influence on the cells (and current home cells) located along the direction of travel from their current location. In this case, the influence means the influence on resources to be preserved in other cells according to the mobility of the mobile terminal. Thus, as the active mobile terminal moves to another cell, the area of influence is continuously changed. As such, the cells currently being affected by the location of the active mobile terminal form an admission related cluster (hereinafter referred to as "ARC").

ARCs may have other shapes, such as oval or diamond shape, and may change over time. This depends on the user's mobility factors such as the distance between the mobile terminal and the base station, the hold time of the current call, the trajectory and speed of the mobile terminal.

For example, having a user mobility model such as a model in a UMTS system, the mobile terminal has a probability of going straight or left / right rotation. In this case, if the straight probability is assumed to be 0.5 and the left turn or right turn probability is set by 0.25, the ARC has a shape as shown in FIG. 3.

FIG. 3 is a diagram illustrating an admission related cluster of neighboring base stations of a mobile terminal according to a user mobility model. In FIG. 3, a cell not painted inside becomes a home cell in which a mobile terminal is currently located. The cells closest to the home cell are denoted by T1, the next closest cells are denoted by T2, and cells farther than the cells of T2 are denoted by T3. In addition, as described above, the probability value of 0.5 was displayed in the straight direction, and the probability values of the left and right rotation directions were 0.25.

The mobile terminal pattern of the user may be configured as a mobility pattern profile (MPP) or a system define threshold in advance in the base station. Using this mobility pattern profile or system defined threshold, the number of ARCs can be reduced.

(1) predictive active probabilities

First, consider a wireless network that uses time divided into equal intervals (t = t ₁ , t ₂ , t _m ). j denotes a base station in a network having n neighboring cells, where j ∈ J, and J is assumed to be the set of all base stations in the wireless network. And x represents a mobile terminal capable of performing an active wireless connection, where x ∈ X and X is assumed to be the set of all active mobile terminals at the current time. Also, in addition to the current home base station, the set of base stations forming the admission related cluster (ARC) of the active mobile terminal x is represented by ARC (x), where k ∈ ARC (x), where k forms the admission related cluster. One of the base stations. The probability density distribution of the user's mobility characteristics and call lengths for different services is known, and it is assumed that a probability density distribution of one-way probability and residence time can be obtained from this. Assume the assumptions above are justified for the following factors.

a) The user mobility pattern profile may be recorded in the network controller.

b) Navigation systems, such as GPS, are used in systems that can provide accurate position, direction and speed.

c) The probability density distribution of call lengths for different services can be obtained from statistical values.

Therefore, each of the assumptions described above makes sense.

Next, it is assumed that h _{x, M (x)} (t) represents the probability distribution function (PDF) for the length of the call for mobile terminal x when using the service with the class descriptor M (x). H _{x, M (x)} (t) is the cumulative distribution function (CDF) for h _{x, M (x)} (t). Under this assumption, the following definitions are possible.

If the probability density function (PDF) matrix L _{x, j} (t) for the residence time for the mobile terminal x in a specific cell j is defined, it may be defined as Equation 1 below.

Here, suppose a mobile terminal enters and exits a cell through side v and side w, respectively. Is the residence time PDF of mobile terminal x in cell j, v, w ∈ [0, n], y = 0 means the call request starts in cell j, w = 0 means the call ends in cell j do. If cell j initiates a resource request, that is, v = 0, to be. Because mobile terminals move, usually Set to.

In addition, when the one-way probability matrix D _{x, j} (t) for the mobile terminal x is defined in cell j, Equation 2 is obtained.

In Equation 2, it is assumed that a mobile terminal enters and exits a cell through side v and side w, respectively. Is a one-way probability for mobile terminal x in cell j, y = 0 means the request originates in cell j and w = 0 means the call ends in cell j. If cell j initiates a resource request, that is, v = 0, to be.

The probability that the mobile terminal x arrives at cell j _k at time t is then equal to the difference in the probability that the mobile terminal is outside cells j _k and j _k-1 at time t. Since mobile terminal x initiates a resource request in cell j ₁ , assuming that there are r routes from j ₁ via side w ₁ to j _s via side w _s , If the mobile terminal is outside of cell j _s along root m at time t, CDF It is necessary to decide. Therefore, the residence time PDF shown in Equation 3 below. Exceed probability PDF by Can be calculated and this equation is Can be used to obtain

The arrival probability matrix will then be in cell j _k at time t, starting at cell j ₁ Can be summarized as in Equation 4 below, assuming that the first exit side and the last entrance side are w ₁ and w _k , respectively.

In Equation 4 above Shows a first side and an outlet side end and out the arrival probability that a cell in a mobile terminal j _k x a time t is started in a cell j ₁ if it is assumed that each of w ₁ and w _k.

Multi-direction Probability Mobile terminal x starting at cell j ₁ is in cell j _s at time t, And assuming that the first exit side and the last exit side are w ₁ and w _k , respectively, it is equal to the product of the one-way probabilities along the root m, which is expressed by Equation 5 below.

The first side and the outlet end and out if the side is assumed that each of w ₁ and w _k, a matrix multi-stage orientation probability in the cell j _k in the cell the mobile terminal is started at time x j ₁ t May be expressed as Equation 6 below.

With all these appropriate considerations, we can calculate the predictive active probability. Assuming that mobile terminal x with call length CDF H _{x, M (x)} (t) starts a resource request at cell j ₁ , the fractional predictive active probability matrix for cell j _k at time t is It may be determined using an equation such as <Equation 7>.

Where v and w each represent an outlet side of cell j ₁ and an inlet side of cell j _k , Is the prime predictive active probability for cell j _s , And Are obtained from Equations 4 and 6, respectively.

Then, a predictive active probability matrix for cell j _k at time t can be obtained as shown in Equation 8 below.

Where v and w each represent an outlet side of cell j ₁ and an inlet side of cell j _k , Is a predictive active probability for the cell j _s at time t, which is expressed by Equation 9 below.

In Equation 7 above end When multiplying by, if the last arc is different, i.e. k And Note that if they differ in the element of, the product is a value of "0".

(2) 3-D analysis of PAP of ARC

Example 1 In the case of 1-D (1-D), high speed mode

For simplicity of explanation, assume that some cells of the rectangular shape cover the high-speed communication path as shown in FIG. In addition, the exact location of the mobile terminal in each cell is unknown and the user does not go back or stop, ie v, w ∈ [0,2], residence time PDF Where the one-step probability is Assume that Arrival probability matrix And multistage probability matrix One-dimensional expression of can be obtained.

(A) If the cell if staying in cell j ₁ from the mobile terminal x, the time t is started in a j _1, that is, if r = k = 1 and v = 0, PAP may be expressed to as the <Equation 10>.

here,

to be.

Due to such a relationship, Equation 10 may be expressed in another form as shown in Equation 11 below.

(B) If mobile terminal x originating in cell j ₁ moves to the right, the entry and exit sides must be side 1 and side 2, ie In accordance with Equation (12) it can be expressed by the relationship.

In Equation 12 above Has a relationship with And since K> 1 Satisfies the relationship of, and the first element in the matrix must be "0". That is, the mobile terminal has no choice but to move to the right. Also because k> 1 Satisfies the relationship of, and the first element in the matrix must also have a value of "0". That is, the mobile terminal has no choice but to move to the right.

(C) If the mobile terminal x started in cell j ₁ moves to the left, it will be a similar equation as shown in Equation 12 above.

Example 2 Multi-Cell Mode for Two-Dimensional (2-D)

For simplicity of explanation, assume that several circular cells are used to cover the respective regions as shown in FIG. In fact, the results of the analysis are not related to cellular form. In addition, it is assumed that the exact location of the mobile terminals in each cell is unknown and there are n neighboring cells. In other words, it is assumed that v, w, [0, n]. Arrival probability matrix And multistage probability matrix You can get a quadratic of.

(A) if the cell remained in the cell j, if j ₁ x a time t from a mobile terminal is started in the _first, that is, if r = k = 1 and v = 0, PAP is represented as the <Equation 13>.

here

to be.

From Equation 13, Equation 13 can be obtained as shown in Equation 14 below.

(B) If the mobile terminal x starting at cell j ₁ is in cell j _k at time t, that is, r> 1 and j _k > j _1, FPAP can be obtained as shown in Equation 15 below.

Where k> 1, the first row in the matrix should always be "0". Therefore, if you rearrange it, PAP is obtained as in Equation 16 below.

Case 3: hierarchical cellular mode for three-dimensional (3-D)

Assume that a circular shape and two tires are used for the hierarchical cellular structure as shown in FIG. 6. In fact, the analysis results are not related to cellular shape and tire count. In FIG. 6, the left side shows a case where there is only one cell in the first tire while the right side shows a case where there is one or more cells in the first tire. In addition, a cell indicated by a thick line among the cells of the right tire and the left tire represents a cell where the mobile terminal is currently located. The exact location of mobile terminals in each cell is not known and it is assumed that there are n neighboring cells. In other words, it is assumed that v, w ∈ [0, n]. Also note that there are n hierarchical cells. Arrival probability matrix And multistage probability matrix You can get a three-dimensional expression of.

(A) It is assumed that the hierarchical cellular system such as the left side of FIG. 6, i.e., the mobile terminal x started in the cell of the first tire, will certainly be in the second tire. (N = 1)

(A.1) if the mobile terminal remains in the cell j ₁ x started from time t ₁ to the cell j, i.e., if r = k = 1 and v = 0, PAP may be illustrated as shown below in <Equation 17> have.

here

to be.

Then, from Equation 17, another form of Equation 17 may be obtained.

(A.2.1) can be obtained if the cell if the cell j ₁ x a time t from the mobile terminal beginning from j _1, the <Equation 3> to <Equation 7> to from <Equation 19>.

if k = 2,

When the relationship of K> 2 is satisfied, the PAP of Equation 19 has the same format as Equation 16.

(A.2.2) if the mobile terminal is cell x j ₁ at the time t is started outside the cell j ₁ (cases other are I will not focus for this is the same as in the case of 2-D), the <Equation 3> According to Equation (7), it is possible to obtain the same PAP format as in Equation 16 except for j ₁ , which is an additionally neighboring cell.

B. The hierarchical cellular system (HCS) is the same as the right side of FIG. 6, and the PAP has the same format as in the case of 2-D, and assumes that the second tire is also one of the neighboring cells.

Admission Control Algorithm

Bandwidth is the most important resource in the system and each base station (BS) has a total of C bandwidth units (BU), which is assumed to be constant over time. The admission control algorithm of FIG. 7 is then examined.

7 is a flow chart of admission control for resource allocation to a mobile terminal according to an embodiment of the present invention. Hereinafter, the admission control flow for resource allocation according to the present invention will be described in detail with reference to FIG. 7.

First, the total number of BUs is represented by Equation 20 below, where C _u (t) and C _f (t) indicate that a bandwidth unit (BU) is used and not used, respectively. In addition, an estimate of the number of BUs to be used by BSj is expressed as in Equation 21 below.

Here, the initial number of BUs in use C _uj (t ₀₎ is a known amount, Is an estimate of the number of BUs to be freed by an active user who ends the call up to time t or moves to another cell, Is an estimate of the number of BUs to be used due to handoff.

Also, c (x) represents the number of BUs to be used by the active mobile terminal x and X _j ∈ X is a set of all active mobile terminals in cell j. The above values may be shown as in Equation 22, Equation 23, and Equation 24, respectively.

The admission control algorithm according to the present invention includes the following six steps.

First, the six processes included in accordance with the present invention will be examined prior to the examination with reference to FIG. 7.

The first step is to check if the current resource can support the requested call. This process can be confirmed by the following Equation 25.

If you can not meet the PAP conditions when staying in the <Equation 17> cell j ₁ from the mobile terminal x, the time t is started in a cell j ₁ by are to perform the fifth process and a sixth process will be described later.

A second process includes transmitting the predictive active probability matrix value calculated from Equation 8 to necessary cells.

In a third process, the information is received from another cell, so that time t = t ₁ , t ₂ ,... Calculate the load factor LF _j (t) for. This calculation may be calculated as in Equation 26.

In addition, since the bandwidth unit BU is the most important resource, it can be modified as follows.

In the fourth process, the values calculated by Equation 26 are collected from neighboring cells. Survival probability for Calculate remind Is calculated as shown in Equation 27.

In Equation 27, Is the known average call duration for mobile terminal x and has a high SE value, which is accepted more frequently than mobile terminals with low values.

The fifth process uses a search table to perform decision functions including dropping probability and QoS variables. A mobile terminal having a high SE value is accepted by Equation 27, and the quality of service (QoS) variable is satisfied.

The sixth process may be used to accept calls to mobile terminals that have different approval procedure criteria having the same SP value.

Next, a process of the control flow according to the present invention will be described with reference to FIG. 7.

When the traffic is received from the user terminal, the traffic classifier 211 classifies the traffic according to whether the traffic required in step 700 is real-time traffic or non-real-time traffic. The traffic classifier 211 transfers this information to the expected resource estimator 212. In operation 702, the expected resource estimator 212 checks whether the bandwidth c (x) of the call requested from the mobile terminal is smaller than or equal to the remaining bandwidth C_free. If the bandwidth of the requested call is less than or equal to the remaining bandwidth as a result of the check in step 702, the process proceeds to step 704; otherwise, the process proceeds to step 722 to reject the requested call.

In step 702 to step 704, the approval related cluster (ARC (x, t)) and the load factor for the mobile terminal requesting the call approval at time t are defined and read. Then, PAP (x, t) is calculated, and the PAP and load factor are updated in the approval related cluster. Thereafter, the expected resource estimator 212 of the admission controller 220 proceeds to step 706 to compare the sum of the bandwidths and the remaining bandwidth C_Free for all terminals. As a result of the comparison of step 706, if the sum of bandwidths for all terminals is less than or equal to the size of the remaining bandwidth, the process proceeds to step 724 to accept the call. On the other hand, if the sum of the bandwidths for all the terminals is greater than the size of the remaining bandwidth as a result of the comparison of step 706, the process proceeds to step 708 to perform a loop according to the present invention.

As described above, when proceeding to the loop according to the present invention, the expected resource estimating unit 212 proceeds to step 710 to calculate a change value Δ (x) according to the mobility of the mobile terminal that requested the call. Also, the maximum change value Δ (x) according to the mobility of the mobile terminal is calculated while satisfying the QoS requested from the mobile terminal. The change value according to the mobility is a value calculated by receiving both a probability of a mobile terminal or a value according to a movement pattern and a probability of entering a call from adjacent cells. After performing this calculation, the estimated resource estimator 212 proceeds to step 712 and the bandwidth value c (x) requested from the mobile terminal is greater than the remaining bandwidth C_free using the calculated value. Check for largeness. If the bandwidth requested from the mobile terminal is greater than the value of the remaining bandwidth in step 712, the process proceeds to step 722 to reject the call, and simultaneously proceeds to step 716.

On the other hand, if the requested bandwidth from the mobile terminal is not greater than the remaining bandwidth as a result of the check in step 712, the process proceeds to step 714 to accept the requested call and then allocates the bandwidth (C_free) to the mobile terminal. Change the value by subtracting c (x)). In step 716, the mobile station checks whether there is another mobile terminal requesting acceptance of the call. If another user exists as a result of the check in step 716, the processes of steps 710 to 716 are repeated. However, if no other user exists, the flow proceeds to step 718 to end the loop according to the present invention.

In operation 720, the approval controller 220 calculates a current state (C_used, C_free) of bandwidth units in the load factor and j cell.

Simulation result or data

Then look at the simulation results of the operation according to the present invention and the data accordingly. Consider the one-dimensional and two-dimensional cases with some real-time services.

In the case of FIG. 4 of 1-D, ten cells cover the highway, and each cell has a capacity of 40 BU. In this simulation, we simulated three services. Voice (1BU), data (5BU) and video (10BU) with a constant call arrival rate of 6 calls / min / cell.

In this hypothetical experiment, applying the method according to the invention, a new mobile terminal is only accepted into the cell when the inverse of its survival probability is above the rejection threshold value. This is the case shown in Fig. 8B. In this case, the use of the maximum bandwidth occurs when approximately equal to 30 BU and the rejection threshold is zero. This value may be larger when no video users are allowed on the network. In comparison, conventional structures have much lower bandwidth utilization at the same call dropping probability. That is, it can be seen that the proposed structure of the present invention significantly improves radio resource utilization and reduces handoff dropping probability.

As shown in FIG. 5, in the case of 2-D 2-D, the influence of arrival speed is analyzed and the ideal approval, user based approval, and cell based approval are compared. Clearly, user based authorization is feasible and has high resource utilization. For most of the same resource utilization, increased cell arrival rate increases the blocking probability. In practice, there is a tradeoff between blocking and dropping probabilities.

As described above, the prediction resource estimation and admission control structure according to the present invention is a method for elastically and effectively realizing a wideband connection in a wireless communication system having a hierarchical cellular structure. Therefore, in the case of applying the present invention, there is an advantage of significantly increasing the radio resource utilization rate and reducing the probability of handoff dropping with a low blocking probability. It also has the advantage that it is very easy to cooperate with other functional entities of radio resource management.

And, the following several factors do not affect the proposed structure. User distribution, currency distribution, and cell size, shape, and tires. The proposed structure is based on user mobility features. Predictive resource estimation along with survival probabilities provide fair priorities for different users.

Also, the concept of different load factor definition admission related clusters (ARC) for different wireless multiple access technologies can be used for admission control in hierarchical cellular systems.

1 is a flowchart of admission control according to a voice-only environment of the prior art;

2 is a block diagram of functional blocks for admission control according to a preferred embodiment of the present invention;

FIG. 3 is a diagram illustrating an admission related cluster of neighboring base stations of a mobile terminal according to a user mobility model; FIG.

4 is a view for explaining a high speed mode (highway) mode of the case of one-dimensional mobility model of a mobile terminal according to the present invention,

5 is a diagram for explaining a multi-cell mode in the case of two-dimensional mobility model of a mobile terminal according to the present invention;

6 is a view for explaining a hierarchical cellular mode in the case of three-dimensional mobility model of a mobile terminal according to the present invention;

7 is a flow chart of admission control for resource allocation to a mobile terminal according to an embodiment of the present invention;

8 is a simulation graph of the handoff dropping probability in the one-dimensional structure and the conventional one-dimensional structure according to the present invention;

9 is a simulation graph of the blocking probability of an arc in a two-dimensional structure and a two-dimensional structure according to the prior art of the present invention.

Claims (11)

A system for allocating resources upon request of a call from a wireless terminal in a wireless communication system including a mobile terminal having mobility and a base station capable of providing a multimedia traffic service, Receive mobility data and session information and feature information of the required traffic from the wireless terminal, receive bandwidth information of neighbor base stations of the base station including the wireless terminal, and receive the base station for the requested traffic from the wireless terminal. An admission control unit which checks whether the call is accepted using the remaining bandwidth information of the mobile station and determines whether the traffic is allocated by checking whether the requested traffic is acceptable from the resource information of neighboring base stations; And a radio resource allocating unit for allocating a radio resource to the wireless terminal according to the decision of the approval controller. The method of claim 1, The control unit according to the mobility of the terminal in the wireless communication system characterized in that it further comprises a scheduling queue for performing the scheduling for the requested traffic, and the allocation of resources according to the result when the determination of the real-time traffic is determined by the admission control unit system. The method of claim 2, wherein the approval control unit, A traffic classification unit for dividing and outputting traffic according to real-time or non-real-time of the traffic requested from the wireless terminal; In the case of the non-real-time traffic, the wireless communication system comprising an expected resource estimator for determining whether to approve the traffic by checking the expected resources according to the remaining bandwidth of the base station including the wireless terminal and the neighboring base station; Resource control system according to the mobility of the terminal. The method of claim 1, Receiving mobility information of the wireless terminal, and considering resource states of adjacent base stations based on predetermined one-dimensional movement information, two-dimensional movement information, and three-dimensional movement information. Resource control system. The method of claim 1, wherein the approval control unit, The resource control system according to the mobility of the terminal in the wireless communication system, characterized in that whether to allocate the traffic by calculating the probability of survival and at the same time to estimate the prediction resource allocation. Claims [1] A method for allocating resources when a call is requested from a wireless terminal in a wireless communication system including a mobile terminal having mobility and a base station capable of providing a multimedia traffic service. Classifying the traffic according to real time when there is a request for traffic from the wireless terminal; Calculating a grant-related cluster in consideration of the probability of progressing to neighboring base stations and the resource status of neighboring base stations if the current resource of the base station including the wireless terminal can accommodate the requested traffic; And accepting the requested traffic when the sum of the total bandwidths using the calculated value of the grant-related cluster is less than or equal to the remaining bandwidth. The method of claim 6, If the sum of the total bandwidths using the calculated value of the authorization-related cluster is greater than the remaining bandwidth, the mobility change of the wireless terminal is calculated, the maximum value according to the mobility change and the required quality of service are calculated, and then the calculated mobility If the value of less than the remaining bandwidth, the step of allocating the traffic further comprising the step of resource control according to the mobility of the terminal in a wireless communication system. The method of claim 7, wherein And rejecting the requested traffic when the calculated mobility value is greater than the remaining bandwidth. The method of claim 7, wherein the mobility change of the wireless terminal, The resource according to the mobility of the terminal in the wireless communication system, characterized in that it is checked whether the resource state of the adjacent base stations can accommodate the change in mobility based on the predetermined one-dimensional movement information, two-dimensional movement information and three-dimensional movement information. Control method. The method of claim 6, wherein upon acceptance of the requested traffic, The method of controlling resources according to mobility of a terminal in a wireless communication system, characterized in that it determines whether to allocate traffic by calculating a survival probability simultaneously with estimating a predictive resource. The method of claim 6, And rejecting the requested traffic when the current resource of the base station including the wireless terminal cannot accommodate the requested traffic.