JP2002159057A - Radio network control station and its code rearrangement start decision method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress activation of useless code relocation instructions. SOLUTION: This is a code rearrangement activation judging method of a radio network controller in a mobile communication network. The usage status of the downlink code is stored in the code table for each subordinate base station, the timer activation time is set (step S502), and when the timer activation time has elapsed, the specific SF can be used with reference to the code table. The number of codes is monitored (step S504). If the number of available codes is smaller than the predetermined threshold, the number of available codes is monitored for SFs lower than the SF with reference to the code table (step S506). Then, code rearrangement is performed according to the available code of the lower SF (step S508).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio network controller and its code relocation activation determination method, and more particularly to a radio network controller and its code relocation activation determination method in a W-CDMA mobile communication network. .

[0002]

2. Description of the Related Art Conventionally, an OVSF (Orthogonal Variable) is used in a W-CDMA mobile communication network.
An information symbol is spread and transmitted using an orthogonal code system called a Spreading Factor code.
By using OVSF, a plurality of channels are configured in the same band and can be distinguished from each other.

FIG. 1 is a view for explaining an example of the configuration of an OVSF code in W-CDMA.

[0004] SF (Spreading Facto)
r) represents a spreading factor, and changes the spreading factor according to the information transmission speed. That is, a channel with a high transmission rate uses a code with a small SF, and a channel with a low transmission rate uses a code with a large SF. The radio controller RNC notifies the user of which code to use.

Here, the same code cannot be used simultaneously in the same time zone. Also, as for the code in which the higher SF is used, the codes of all SFs under (being derived from) the higher SF cannot be used. On the other hand, for a code using a lower SF, the code of the higher SF cannot be used.

Due to the nature of such a code, in the following cases, the code utilization efficiency may be reduced.

In FIG. 1, for example,
Assigns a key. (1) User A has made a request for low-speed communication. This
In the case of, it is sufficient to assign a code of SF = 4.
The device is code C for A_{ch , Four , 0}Assigned. (2) User B has made a request for high-speed communication. This
Requires a code of SF = 2. Where C_{ch , Two
, 0}I want to assign, but the subordinate C_{ch , Four , 0}Lotus
The control unit is C_{ch
, Two , 1}Assigned. In this case, Cch, 4, 1 are unused
Remains.

[0008] In an actual operation in a commercial station, SF = 25
Since codes such as 6, 128, and 64 are frequently used, while allocating codes in response to a request from a user, as described below, the "wormworm state" of the code usage status will be described below.
Is more likely to occur. 1. _1. Assigned _{Cch , 8 , 0} to the request of SF = 8. 2. Assigned _{Cch , 8 , 1} to the request of SF = 8. _{3. Cch , 8 and 2} are assigned to the request of SF = 8. _Cch against SF = 4 of the _{request, 4, 2} was assigned _{(C ch, 4, 0 C} ch, 4, 1 both in use) 5. _5. The user of C _{ch , 8 , 0} ends the call. _6. Users on _{Cch , 8 and 2} end the call. SF = While second request came, not be allocated for code shortage, a call loss (however, _{Cch, 8,} if the _first user is switched to _{Cch, 8, 6 Cch, 2, 0} is available Becomes).

In order to avoid such a situation, a conventional W
-In the CDMA mobile communication system, a technique called downlink code rearrangement is prepared.

FIG. 2 is a diagram illustrating an example of a system configuration of a conventional W-CDMA mobile communication system.

[0011] The W-CDMA mobile communication system includes at least a radio network controller 100 and an exchange 20.
0, the base station 300, and the mobile station 400.

The radio network controller 100 has a function of controlling a radio section, and has a code table 120 for managing the use status of the OVSF code.

FIG. 3 shows a conventional radio network controller 1.
FIG. 14 is a diagram showing an example of a processing flow of code rearrangement at 00.

First, a timer for monitoring the use status of the code is activated in one minute at regular intervals (step S30).
2) Each time the timer expires, the code table 120 is accessed to determine whether the number of remaining SF = 8 codes is three or less.
That is, it is checked whether five or more are used (step S304), and the usage status is monitored.

Next, when the number of remaining codes of SF = 8 is three or less, the codes are uniformly rearranged to eliminate the worm-eating state.

As described above, the radio network control station 10
In the case of 0, the remaining available code number of a specific SF is periodically monitored, and when the remaining code number falls below a certain value,
Downlink code relocation is activated.

[0017]

However, conventionally, since only the number of remaining codes of a specific SF is monitored, whether a "worm-eating state" has occurred and the code utilization efficiency has been reduced or the resources themselves have not been monitored. There is a problem that it cannot be distinguished whether it is insufficient.

Although the effect of rearrangement can be obtained when the use efficiency of the code is low, even if the code resources are insufficient, the downstream code rearrangement is activated at a constant period, which is inefficient. There is a problem.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a radio network control station capable of suppressing the activation of useless code relocation instructions by performing a code relocation activation determination a plurality of times, and a code for the radio network control station. An object of the present invention is to provide a rearrangement start determination method.

[0020]

In order to achieve the above object, according to the present invention, a radio network control station in a mobile communication network uses a downlink code for each subordinate base station. Means for storing a situation in a code table, means for setting a timer activation time, means for monitoring the number of available codes of a specific SF by referring to the code table when the timer activation time has elapsed, If the number of available codes is smaller than a predetermined threshold, the code table is referred to and the lower SF of the SF is referred to.
Means for monitoring the number of available codes for F.
It is characterized in that it is determined whether or not to execute the code rearrangement according to the available code of the lower SF.

According to a second aspect of the present invention, in the wireless network control station according to the first aspect, the mobile communication network is a W-CDMA mobile communication network.

According to a third aspect of the present invention, in the wireless network control station according to the first aspect, the code is O.
VSF (Orthogonal Variable S)
(Reading Factor) code.

According to a fourth aspect of the present invention, in the wireless network control station according to the first aspect, the specific SF
Is 8, and the threshold value is 4.

According to a fifth aspect of the present invention, in the wireless network control station according to the first aspect, the timer activation time, the lower SF, or the threshold value are determined based on a radio link occurrence rate and / or an average hold for each SF. It is characterized by being determined according to time.

According to a sixth aspect of the present invention, in the code relocation activation determination method of the radio network controller in the mobile communication network, the step of storing the use status of the downlink code for each subordinate base station in a code table; Setting a timer activation time; monitoring the number of available codes of a specific SF by referring to the code table when the timer activation time has elapsed; Monitoring the number of available codes for the lower SFs of the SF by referring to the code table if the number is less than the number of available codes, and performing code relocation according to the available codes of the lower SFs. Is determined.

According to a seventh aspect of the present invention, in the method of the sixth aspect, the mobile communication network is a W-CDMA mobile communication network. It is characterized by.

According to an eighth aspect of the present invention, in the method of determining a code rearrangement activation of the radio network controller according to the sixth aspect, the code includes an OVSF (Orthogon).
alVariable Spreading Fact
or) code.

According to a ninth aspect of the present invention, in the method of determining a code relocation activation of the radio network controller according to the sixth aspect, the specific SF is 8 and the threshold is 4
It is characterized by being.

According to a tenth aspect of the present invention, in the code relocation activation judging method of the radio network controller according to the sixth aspect, the timer activation time, the lower SF or the threshold value is a radio link for each SF. It is determined according to the incidence rate and / or the average holding time.

According to the above configuration, by performing the activation determination of the code rearrangement a plurality of times, the code rearrangement can be executed only when the code use efficiency is low, and the unnecessary code rearrangement instruction can be activated. It is possible to provide a radio network control station that can be suppressed and a code rearrangement activation determination method thereof.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In the following embodiment, W-CDM
A mobile communication system will be described as an example.

FIG. 4 is a diagram showing an example of functional blocks of the radio network controller 100 in the W-CDMA mobile communication system of the present invention. Is conceptually shown. Here, in the hardware configuration of the wireless network control station 100, each functional block described in FIG. 4 includes a CPU, a disk device, a memory device, an input device, an output device, a communication control device, and a program for controlling them. And so on.

The radio network control station 100 of the present invention
Are at least a timer value setting unit 102, a code table access unit 104, a code use efficiency determination unit 106
, A code rearrangement unit 108, and a code table 120.

The timer value setting unit 102 has a function of setting a timer time for managing activation of code relocation. The code table access unit 104 has a function of accessing the code table 120 to refer to and update. The code use efficiency determination unit 106 has a function of determining the use efficiency of the code recorded in the code table 120, and monitors the number of remaining codes of a plurality of SFs. Since the number of remaining codes of a specific SF is related to the number of remaining codes of other SFs, it is possible to obtain code use efficiency. For example, the number of remaining codes of SF = 32 and SF = 128
Monitor the number of remaining codes. When the codes are used efficiently, when the number of remaining codes of SF = 32 is 16, the number of remaining codes of SF = 128 can be predicted to be about 64. However, when the code use efficiency is reduced, even if the number of remaining codes of SF = 32 is 16, S
The number of remaining codes for F = 128 is much more than 64. As a result, the use efficiency of the code can be known, so that the start of the relocation can be determined. The code rearrangement unit 108 has a function of executing code rearrangement as described later. The code table 120 is a table for managing the use status of the code for each base station, and includes at least a code recording unit and a user recording unit, and records the correspondence between the code and the user who uses the code. .

Next, an example of the operation of the radio network control station 100 according to the present embodiment configured as described above will be described in detail with reference to FIGS.

FIG. 5 is a flowchart showing an example of the operation of the radio network controller 100 of the present invention.

First, the timer value setting unit 102 of the radio network controller 100 sets a timer time a for managing activation of code rearrangement, and activates the timer (step S502).

Next, the code use efficiency determining unit 106 of the radio network controller 100 accesses the code table 120 via the code table access unit 104, and determines whether the remaining codes of SF = 8 are three or less (ie, 5
More than one is in use) is determined (step S504).

If the number of remaining codes is three or less, it is determined whether the number of lower-order SF = N codes is equal to or less than a predetermined threshold M (step S506).

If the remaining code is M or less, the code is rearranged as described later (step S508).

As a result, the lower-level usage status is determined based on the determination result of the higher-level usage status. Therefore, by performing the activation determination of the code relocation a plurality of times, the code resource itself is insufficient. In this case, since the code rearrangement is performed only when the code usage state is the worm-like state without executing the code rearrangement, useless activation of the code rearrangement instruction can be suppressed. Further, the determination of the lower-level usage status may be performed a plurality of times with the hierarchy further lowered, so that a more accurate usage status of the code can be grasped.

Here, the TIM in step S502
The determination of the setting value a of the ER and the setting of the values of N and M in step S506 are based on the radio link (R
aio Link) and the average holding time. Further, as general factors for determining them, for example, the factors may be determined based on a cell radius, a moving speed of a terminal, a service type (voice / data, etc.), a service continuation time, and the like. Further, as direct factors that consume code resources, for example, a location registration request, diversity handover DHO (Diversity Ha
ndover), Hard Handover HHO (Har
d Handover), outgoing or outgoing sectors, outgoing requests, incoming requests, switching from a common CH to an individual CH, or the like may be used. Here, the radio link refers to a connection required to flow data dedicated to the mobile station, which connects the mobile station, the base station, and the radio network controller.
The radio link occurrence rate for each SF is calculated based on the probability that a mobile station that is not performing communication issues a location registration request, the probability that a mobile station transmits a call, the probability of receiving a call, the probability that a mobile station during communication enters the corresponding cell, the corresponding cell. Is the probability of handling a large amount of packet data and requesting switching from the common CH to the individual CH.
As described above, there are several factors in obtaining the RL occurrence rate, and it is difficult to calculate the RL occurrence rate. The calculation may be performed by simulation or the like.

The situation in which a radio link occurs includes a location registration request, inflow into a sector by DHO or HHO, a transmission request, a reception request, switching from a common CH to an individual CH, and the like. Here, switching from the common CH to the individual CH is performed when there is a request to transmit and receive large data during packet communication.

(Relationship between Downlink Channelization Code and Occurrence and Release of Radio Link) Downlink channelization code is managed for each cell in the BTS. Therefore, the mobile device in communication approaches the cell,
When an RL occurs due to an outgoing / incoming call, a downlink channelization code is issued in the corresponding cell. Also, when the mobile station that is communicating leaves the cell or ends the call and the wireless link is released, the used code is released and this code can be reassigned to another mobile station. Will be possible. If the code allocation is performed in consideration of the position of the released code, the code does not become “wormy”. However, the current code assignment does not perform control to fill the released code first. Therefore, if the occurrence or release of the RL is frequently performed, the probability that the cord is wormy will increase.

(Regarding Code Relocation Procedure) FIG. 6 is a diagram for explaining an example of the processing flow of the code relocation procedure of the present invention.

The code rearrangement procedure is performed from a code having a large SF. Control is performed to shift the assigned code to one side so that it is possible to assign a code with the smallest possible SF.

First, the code used is searched for from the right side of the code Tree.
A code that can be assigned is searched from the left side of ee, and if found, an instruction is given to the user to change the code to be used. Then, the following procedure is executed for the code of the same SF.

When the above procedure cannot be executed, or when the search code becomes the same as the search code, the rearrangement of the code in the SF is terminated, and the object is moved to the code of the next higher SF. Perform the relocation procedure. Subsequently, the following procedure is executed for the code of the target SF.

When the rearrangement of the code of SF = 8 cannot be executed finally, the code rearrangement procedure ends.

(Other Embodiments) In the above-described embodiment, the case where the number of available codes of SF = 8 is 3 has been described as an example. However, the present invention is not limited to this case. In another embodiment, the number of available codes of another SF may be used as a reference.

In the above-described embodiment, W
-The case where the CDMA system is used has been described as an example, but the present invention is not limited to this case, and any method that uses the present invention can be implemented in any case. It is obvious to those skilled in the art.

Further, in the above-described embodiment, the case where each embodiment is realized independently has been described as an example. However, the present invention is not limited to this case. It is obvious to those skilled in the art that the embodiments can be combined as appropriate.

Further, the storage contents of the code table shown in FIG. 4 are merely examples, and another storage unit or the like may be stored in the table. Further, as described above, an example of each table has been shown and each embodiment has been described. However, the present invention is not limited to such an embodiment, and any other table may be used. Further, in the above-described embodiment, the case where the code table is configured alone is described as an example. However, the present invention is not limited to this case, and each table described above requires a plurality of tables. It is obvious to those skilled in the art that the present invention can be implemented in any of the configurations appropriately combined.

Further, in the above-described embodiment, the service and system system of NTT DOCOMO (company name) have been described as an example. However, the present invention is not limited to this case. Instead, in other embodiments, the present invention may be applied to other companies' services and system systems having the same functions.

Further, various modifications other than those described above are possible. However, as long as the modification is based on the technical idea described in the claims, the modification falls within the technical scope of the present invention.

[0057]

As described above in detail, according to the present invention, the number of available codes of a specific SF and its subordinate SFs is monitored. It is possible to provide a radio network control station and a code rearrangement activation judging method capable of discriminating whether it is down or the resource itself is insufficient.

Further, according to the present invention, the effect of rearrangement is obtained when the code utilization efficiency is reduced, but when the code resources are insufficient, the radio network control station in which downlink code rearrangement is not activated. And a code rearrangement start determination method thereof.

Further, according to the present invention, a radio network control station capable of suppressing activation of useless code relocation instructions by performing activation determination of code relocation a plurality of times, and its code relocation activation determination A method can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a configuration of an OVSF code in W-CDMA.

FIG. 2 is a diagram illustrating an example of a system configuration of a conventional W-CDMA mobile communication system.

FIG. 3 is a diagram showing an example of a processing flow of code rearrangement in a conventional radio network control station 100.

FIG. 4 is a diagram showing an example of functional blocks of the radio network controller 100 in the W-CDMA mobile communication system of the present invention.

FIG. 5 is a flowchart showing an example of the operation of the wireless network control station 100 of the present invention.

FIG. 6 is a diagram illustrating an example of a processing flow of a code rearrangement procedure according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 wireless network control station 102 timer value setting unit 104 code table access unit 106 code use efficiency determination unit 108 code rearrangement unit 120 code table 200 exchange 300 base station 400 mobile unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinnobu Ishikawa 2-1-1-1, Nagatacho, Chiyoda-ku, Tokyo Inside NTT DoCoMo, Inc. (72) Inventor Kota Fujimura Machiji Nagata, Chiyoda-ku, Tokyo No. 11-1, NTT Docomo Co., Ltd. (72) Inventor Takaaki Sato 2-1-1, Nagatacho, Chiyoda-ku, Tokyo F-term in NTT Docomo Co., Ltd. (Reference) 5K022 EE02 EE11 5K067 AA11 AA13 BB02 CC10 DD11 EE02 EE10 EE16 EE71 GG01 GG11 HH22

Claims (10)

[Claims] 1. A radio network control station in a mobile communication network, wherein: a means for storing a use status of a downlink code in a code table for each subordinate base station; a means for setting a timer activation time; Means for monitoring the number of available codes of a specific SF by referring to the code table when elapses, and referring to the code table when the number of available codes is smaller than a predetermined threshold. Means for monitoring the number of available codes for lower SFs of the SF, and determining whether or not to execute code relocation according to the available codes of the lower SFs. . 2. The radio network controller according to claim 1, wherein the mobile communication network is a W-CDMA mobile communication network. 3. The radio network controller according to claim 1, wherein the code is an OVSF (Orthogonal Va).
A radio network control station, wherein the radio network control station is a removable spreading factor code. 4. The radio network controller according to claim 1, wherein the specific SF is 8, and the threshold is 4. 5. The radio network controller according to claim 1, wherein the timer activation time, the lower SF, or the threshold is determined according to a radio link occurrence rate and / or an average suspension time for each SF. Radio network control station. 6. A method for judging code relocation activation of a radio network controller in a mobile communication network, comprising the steps of: storing a use status of a downlink code in a code table for each subordinate base station; and setting a timer activation time. Monitoring the number of available codes of a specific SF by referring to the code table when the timer activation time has elapsed; and when the number of available codes is smaller than a predetermined threshold, Monitoring the number of available codes for the lower SFs of the SF with reference to a code table, and determining whether or not to execute code relocation according to the available codes of the lower SFs. Code relocation start determination method. 7. The method according to claim 6, wherein the mobile communication network is a W-CDMA mobile communication network. Startup determination method. 8. The method according to claim 6, wherein the code is an OVSF (Orthogonal Va).
A code relocation activation determination method, characterized in that the code relocation activation code is a removable spreading factor code. 9. The method according to claim 6, wherein the specific SF is 8, and the threshold is 4. Method. 10. The method according to claim 6, wherein the timer activation time, the lower SF, or the threshold value is a radio link occurrence rate and / or an average hold for each SF. A code rearrangement activation determination method characterized by being determined according to time.