KR100365722B1 - Assignment Method of Downlink Channelisation Codes in Mobile Communication System - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a downlink channelization code allocation method in a mobile communication system.

2. The technical problem to be solved by the invention

According to the present invention, when there are various traffics such as voice, data, and video, and the number of codes to be allocated at the call request of each traffic is different, each traffic is transmitted from among the downlink channelization code resources of the base station. By appropriately calculating the number of codes to be used exclusively and the number of codes to be shared, and allowing some traffic to be used exclusively and some to be shared and used by each traffic, code resources are satisfied while satisfying service criteria such as blocking probability. It is an object of the present invention to provide a method for allocating a downlink channelization code in a mobile communication system and a computer-readable recording medium having recorded thereon a program for realizing the method.

3. Summary of the Solution of the Invention

The present invention is a downlink channelization code allocation method applied to a mobile communication system, the number and sharing of codes dedicated to each traffic type based on the number of calls (call) for each traffic type and the required code per call Calculating a number of codes to be used; And checking the code resources within the number of dedicated codes and the number of shared codes used in the first step according to the traffic type that requested the call, and if there are available codes, the available codes in the requested call. And a second step of rejecting the required call if no code is available.

4. Important uses of the invention

The present invention is used for downlink channelization code allocation in the mobile communication system.

Description

Assignment Method of Downlink Channelization Codes in Mobile Communication System

The present invention relates to a method for allocating downlink channelization codes in a mobile communication system. In particular, various traffic such as voice, data, and video exist, and codes to be allocated at the call request of each traffic are provided. If the number is different, in the downlink channelization code resources of the base station, the number of codes dedicated to each traffic and the number of codes to be shared are appropriately calculated, and some are dedicated to each traffic. In addition, some of them share and use each traffic, thereby allocating downlink channelization code in a mobile communication system that satisfies service criteria such as blocking probability and uses code resources as efficiently as possible. A method and a computer readable recording medium having recorded thereon a program for realizing the method.

In general mobile communication systems, code resources are limited, and resources must be managed and used as efficiently as possible in order to provide a service that satisfies the needs of customers by using the limited resources.

In the IMT-2000 system that accommodates various traffic such as voice, data, and video traffic, different call quality and transmission rate are required for each traffic type, so the efficient use of code resources becomes more important.

1 is an explanatory diagram of conventional fully shared code (CS code) allocation, and illustrates a method of allocating a completely shared (CS) code in which each type of traffic shares and uses an entire code resource. Indicates.

First, the CS (Completely Shared) code allocation method is a method of sharing the entire code (code) resources, each traffic is used to share all the codes (code).

The amount of channelization code resources required by one call of 12.2 Kbps voice, 64 Kbps data, and 384 Kbps video traffic is assumed to be 1 code, 8 code, and 32 code, respectively.

In the case of data and video traffic, 8 and 32 numbers starting from the (1 modulo 8) and (1 modulo 32) codes of the total channelisation codes (assuming 256 codes) assigned to one base station, respectively. Code must be present in sequence to assign code to the call request.

In the case of voice traffic with a small number of codes required by a call, since there are many codes available, the blocking probability is relatively low, but data requiring 8 codes and video traffic requiring 32 codes are relatively low. As for the traffic, the traffic is increased because the 8th and 32th codes starting from the (1 modulo 8) and the (1 modulo 32) codes among the 256 codes assigned to one base station can be accepted only if they are empty continuously. Accordingly, there is a problem that the blocking probability may increase rapidly.

FIG. 2 is a structural diagram of a code tree providing conventional OVSF codes, and illustrates a code tree providing orthogonal variable spreading factor (OVSF) codes that are the basis of a channelization code. .

Constraints exist in the use of channelisation codes, which means that if you are currently using a particular code, you will not be able to use fewer SF codes on the root path of the tree. There was this.

For example, if the C _4,4 code (SF = 4) is already in use, then the C _2,2 code (SF = 2) or the C _1,1 code (SF = 1) cannot be used.

The present invention has been made to solve the above problems, and when there are various traffic such as voice, data, and video, and the number of codes to be allocated at the call request of each traffic is different, the downlink of the base station ( downlink) channelization code A resource that calculates the number of codes dedicated to each traffic and the code to be shared for each resource, so that each traffic is dedicated and some traffic is shared and used. An object of the present invention is to provide a method for allocating a downlink channelization code in a mobile communication system and a computer-readable recording medium having recorded thereon a program for realizing the method.

1 is an explanatory diagram of a conventional fully shared (CS) code assignment method.

2 is a structural diagram of a code tree providing conventional orthogonal variable spreading factor (OVSF) codes.

FIG. 3 is a diagram illustrating an embodiment of a method for allocating a Partially Dedicated Partially Shared (PDPS) code according to the present invention; FIG.

4 is a flowchart of an embodiment of a code allocation method for a voice call request according to the present invention;

5 is a flowchart of an embodiment of a code allocation method for a data call request according to the present invention;

6 is a flowchart illustrating a code allocation method for a call request of video traffic according to the present invention.

In order to achieve the above object, the present invention provides a method for allocating a downlink channelization code applied to a mobile communication system, based on the number of call types and the required code per call. A first step of calculating the number of codes dedicated to the traffic type and the number of codes shared and used; And checking the code resources within the number of dedicated codes and the number of shared codes used in the first step according to the traffic type that requested the call, and if there are available codes, the available codes in the requested call. And a second step of rejecting the required call if no code is available.

On the other hand, the method of the present invention, in order to assign a downlink channelization code, a mobile communication system having a processor, based on the number of calls (Call) by traffic type and each code based on the required code (Code) per call A first function of calculating the number of codes dedicated to the traffic type and the number of codes shared and used; And checking the code resources within the number of dedicated codes and the number of shared codes used in the first function according to the traffic type that requested the call, and if there are available codes, the available codes in the requested call. And a computer readable recording medium having recorded thereon a program for realizing a second function of rejecting the requested call if no code is available.

In the asynchronous IMT-2000 system, various services such as voice, data, and video traffic should be provided. In the present invention, asynchronous IMT-2000 is used for a typical 12.2 Kbps voice traffic, 64 Kbps data traffic, and 384 Kbps video traffic. A code allocation scheme is proposed to efficiently use downlink channelization code resources of each base station in a system.

In order to efficiently use the downlink channelization code resources of the base station, some of the entire code resources are partially dedicated, and some are shared with other traffic types. The present invention relates to a PDPS code allocation method that is used (Partially Shared).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating a method for allocating a Partially Dedicated Partially Shared (PDPS) code according to the present invention.

The code allocation method in the IMT-2000 system according to the present invention is based on the number of calls for each traffic type and the number of codes required per call, and the number of codes exclusively used by each traffic type. Calculating a number of codes to be used and assigning codes to call requests.

In the present invention, in the IMT-2000 system which requires different call quality and transmission rate for each traffic type, a code area for each traffic type to be used exclusively on the basis of the number of calls for each traffic type and the number of codes required per call. In this case, code areas that can be shared and used by two traffic types are distinguished and operated.

Accordingly, the number of codes used exclusively for each traffic type and the number of codes used for sharing should be determined.The amount of traffic expected during system implementation (number of calls for each traffic type and required codes per call) Count the number of dedicated and shared codes. At this time, the number of codes to be dedicated and shared is calculated from the traffic having a large amount of resources required by one call.

Hereinafter, a process of calculating the number of codes required by each traffic based on the number of calls for each traffic type and the required number of codes per call will be described.

First, the symbols to be used in the following calculation process will be defined. c ₁ , c ₂ , and c ₃ represent the number of calls added per unit time of voice, data and video traffic, and γ ₁ , γ ₂ and γ ₃ represent the number of codes required for one call of voice, data and video traffic. C represents the total number of code resources (number of codes), and ( n ₁ , n ₂ , n ₃₎ represents the actual number of codes to be allocated to the added voice, data, and video calls.

First, based on the number of calls for each traffic type ( c ₁ , c ₂ , c ₃ ) and the required number of codes per call (γ ₁ , γ ₂ , γ ₃ ), the temporary quota for each traffic type ( t ₁ ) of the total code ( t ₁₎ , t ₂ , t ₃ ).

That is, when CCR (Code to Call Ratio) is obtained from Equation 1 below, Equation 2 is obtained.

( c ₁ · γ ₁ + c ₂ · γ ₂ + c ₃ · γ ₃ ) CCR = C

CCR = C / ( c ₁ · γ ₁ + c ₂ · γ ₂ + c ₃ · γ ₃ )

Then, the temporary quotas ( t ₁ , t ₂ , t ₃ ) for each traffic type are calculated using Equation 3 below.

t ₁ = CCR · ( c ₁ · γ ₁ )

t ₂ = CCR · ( c ₂ · γ ₂ )

t ₃ = CCR · ( c ₃ · γ ₃ )

Second, the actual quotas ( n ₁ , n ₂ , n ₃ ) for each traffic type are calculated from the temporary quotas ( t ₁ , t ₂ , t ₃ ). For example, for a video call, if t ₃ = 48, the actual quota ( n ₃ ) must be 32 or 64, which is a multiple of 32 (assuming 32 required codes per call). Can be applied.

At this time, "method 1" is the same as the following (Equation 4), "method 2" is the same as the following (Equation 5).

here, Is a minimum integer greater than or equal to x , Is the largest integer less than or equal to x .

Here, s ₂ and s ₃ each have a value of 1 or more as a slack coefficient for data and video traffic. In view of the second method (Equation 5), Method 1 (Equation 4) can be regarded as a special case where s ₂ and s ₃ both have a value of 1.

Third, review the following:

t ₁ < n ₁ + n ₂

t ₂ < n ₂ + n ₃

It is not satisfied by examining that satisfy the (expression 6) reducing the n ₃ so as to satisfy the above expression increases the n _2. In the above equation, ( n ₁ + n ₂ ) is the maximum number of codes that voice traffic can use, ( n ₂ + n ₃ ) is the maximum number of codes that data traffic can use, and the maximum number of codes that video traffic can use. Is n ₃ .

For example, the above process will be described. At this time, consider the case where the call (hour) per unit time (equation 7) as follows.

c ₁ : c ₂ : c ₃ = 100: 8: 1

In addition, assume that C is 256 (code), γ ₁ , γ ₂ , and γ ₃ are 1, 8, and 32 (code), respectively. Then, CCR and ( t ₁ , t ₂ , t ₃ ) can be obtained through Equations 8 and 9 below.

CCR = C / ( c ₁ · γ ₁ + c ₂ · γ ₂ + c ₃ · γ ₃ )

= 256 / (100 + 64 + 32)

= 1.306

t ₁ = CCR · ( c ₁ · γ ₁ ) = 131

t ₂ = CCR · ( c ₂ · γ ₂ ) = 83

t ₃ = CCR · ( c ₃ · γ ₃ ) = 42

If the "method 1" (see Equation 4) is used, the same result as Equation 10 can be obtained.

Let's examine whether the result satisfies the basic condition as shown in Equation 11 below.

t ₁ < n ₁ + n ₂ = 112 + 80 = 192

t ₂ < n ₂ + n ₃ = 80 + 64 = 144

Thus, the number code being dedicated to voice calls (n ₁₎ is code that is allocated to the dog 112, the 80 voice and data calls can code being assigned in common (n _2), data and video call interface (n ₃ ) Will be 64.

4 is a flowchart illustrating a code allocation method for a voice call request according to the present invention.

When a voice call (12.2 Kbps voice call) is generated to request a code assignment to a base station (401), it is used in an allocated code area (area A in Fig. 3) for exclusive use of the voice call. Check if there is a possible code (402).

As a result of the check, if there is a code available, a code is assigned (accept the call) for the call request (403). If no code is available, then it is checked (404) that there is an available code within the code area (B area in Figure 3) intended to be shared with the data traffic.

As a result of the check, if there is a code available in the shared code area, the code is assigned to the call (accept the call) (405), and there is no code available in the shared code area. If not, the call is rejected (blocked) (406).

As a result of checking "404", when there are several codes available in the shared area with the data traffic, the codes are assigned in the following manner.

Codes in the code group with the lowest number of available codes, starting from the (1 modulo γ ₂ ) code and reviewing the number of available codes in units of γ ₂ consecutive code groups Allocate (code) If more than one, one of them is randomly assigned.

For example, when γ ₂ = 8, if the number of usable codes is 1 in the code groups 1 to 8 and the number of usable codes in the remaining code groups is 2 or more, the usable codes of the code groups 1 to 8 are used. Allocate

5 is a flowchart illustrating a code allocation method for a data call request according to the present invention.

When a data call (64 Kbps packet call) is generated and a code assignment is requested from the base station (501), the data call and voice call are used in a code area (region 3B) allocated for common use. Check if there is a possible code (502).

As a result of the inspection, if there is an available code, a code is assigned to the corresponding data call (503), and if there is no available code, a code area that is to be shared with video traffic (drawings Check whether there is an available code in the C region of 3) (404), if there is an available code, assign a code to the corresponding code (405), and the available code is If not present, the corresponding call is blocked (406).

As a result of checking "504", when there are several codes available in the shared area with the video traffic, codes are assigned in the following manner.

Starting with the (1 modulo γ ₃ ) code, review the number of available codes in γ ₃ consecutive code group units, and select the code of the code group with the lowest number of available codes. Assign. If more than one, one of them is randomly assigned.

6 is a flowchart illustrating a code allocation method for requesting video traffic according to the present invention.

When a video call is generated and a code assignment is requested to a base station (601), a code can be used in a code area allocated to the video call and data call for common use (region C in FIG. 3). Check if it is (602)

As a result of the check, if an available code exists, a code is assigned to the call request (603), and if the available code does not exist, the corresponding block is blocked (604).

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains, and the above-described embodiments and accompanying It is not limited by the drawings.

As described above, the present invention provides a dedicated code area (if a voice call) according to its call type in each call request in an environment in which various types of traffic having different transmission rates such as voice, data, and video traffic exist. If a code is assigned first in a shared area (for data calls and video calls) with a call with a smaller number of codes per call, and there is no code available in the code area, Code resources are allocated in a shared area (for voice and data calls) with calls with a larger number of codes per call, so that the entire code resources are shared and used. There is an effect that can be used efficiently.

That is, according to the present invention, if the traffic is appropriately calculated and the number of codes to be used exclusively and the number of codes to be shared, the code is allocated at the time of call request. Compared to the case of sharing, it is possible to efficiently use code resources while satisfying service criteria such as blocking probability.

Claims (8)

In the downlink channelization code allocation method applied to a mobile communication system, A first step of calculating the number of codes dedicated to each traffic type and the number of shared codes based on the number of calls per traffic type and the required codes per call; And According to the traffic type that requested the call, the code resources in the number of dedicated codes and the number of shared codes used in the first step are examined, and if there are available codes, the available codes are placed in the requested call. Second step of allocating and rejecting the requested call if no code is available Downlink channelization code allocation method in a mobile communication system comprising a. The method of claim 1, The first step is, A third step of calculating a temporary allocation amount for each traffic type among all codes based on the number of calls per traffic type and the required number of codes per call; A fourth step of calculating an actual allocation amount for each traffic type from the temporary allocation amount for each traffic type calculated in the third step; And A fifth step of calculating the number of codes dedicated to each traffic type and the number of shared codes from the relationship between the temporary allocation amount for each traffic type and the actual allocation amount for each traffic type Downlink channelization code allocation method in a mobile communication system comprising a. The method according to claim 1 or 2, The second step, If the traffic requesting the call is voice traffic, it is checked whether there is a code available in the dedicated code area of the voice call, and if there is a code available in the dedicated code area, a code is assigned to the requested call, and the dedicated code If there is no code available in the region, a sixth step of checking whether there is a code available in the shared code region with data traffic; And A seventh step of allocating a code to the requested call if there is a code available in the shared code area as a result of the sixth step, and rejecting the requested call if there is no code available in the shared code area. Downlink channelization code allocation method in a mobile communication system comprising a. The method of claim 3, wherein The code assignment of the seventh step, Codes consecutive from the first code "modulo" number of codes required for one data traffic call (γ ₂ ) "" starting with the "number of codes required for one data traffic call (γ ₂ )" A method for allocating downlink channelization codes in a mobile communication system, characterized by allocating codes of a code group having the smallest number of available codes by examining codes usable in units of code groups. The method according to claim 1 or 2, The second step, If the traffic requesting the call is data traffic, it is checked whether there is a usable code in the shared code area of the voice traffic and the data traffic. A sixth step of allocating a code for and checking if there is a code available in the shared code area of the data traffic and the video traffic if no code is available in the code area of the voice and data traffic; And As a result of the checking in the sixth step, if there is a code available in the shared code area of the data traffic and the video traffic, a code is assigned to the requested call, and the code available in the shared code area of the data traffic and the video traffic is If not, the seventh step of rejecting the requested call Downlink channelization code allocation method in a mobile communication system comprising a. The method of claim 5, The code assignment of the seventh step, Codes consecutive from the first code "modulo" number of codes required for one video traffic call (γ ₃ ) "" starting with the "number of codes required for one video traffic call (γ ₃ )" A method for allocating downlink channelization codes in a mobile communication system, characterized by allocating codes of a code group having the smallest number of available codes by examining codes usable in units of code groups. The method according to claim 1 or 2, The second step, A sixth step of checking if there is a code available in the shared code area of the video traffic and data traffic if the traffic requesting the call is video traffic; And As a result of the checking in the sixth step, if there is a code available in the shared code area of the video traffic and data traffic, a code is assigned to the requested call, and if there is no code available in the code area of the video traffic and data traffic, Seventh step of rejecting the requested call Downlink channelization code allocation method in a mobile communication system comprising a. In a mobile communication system having a processor for downlink channelization code allocation, A first function of calculating the number of codes dedicated to each traffic type and the number of codes to be shared based on the number of calls per traffic type and the required code per call; And According to the traffic type requesting the call, the code resources in the dedicated number of codes and the number of shared codes used in the first function are examined, and if there are available codes, the available codes are added to the requested call. A second function of assigning and rejecting the requested call if no code is available A computer-readable recording medium having recorded thereon a program for realizing this.