KR100873386B1 - Method and apparatus for allocating communication frequency for inducing even multi-frequency distribution in WCDMA system - Google Patents

Abstract

According to the present invention, in a WCDMA system in which multi-Frequency Allocation (FA) cells are operated, various methods, such as a random function method, are used to determine the communication frequency of a mobile terminal without interworking with RRM (Radio Resource Management) during the location registration process of the mobile terminal. The present invention relates to a communication method and apparatus for a WCDMA system that can distribute a location registration load by inducing an even distribution of multiple FAs. In a wireless communication system operating multiple FAs according to the present invention, a method of allocating frequencies includes repetitively selecting or randomly selecting respective FAs in response to a received message to determine frequencies. May be used in the location registration process of the mobile terminal in the idle state.

WCDMA, multi-FA, location registration, RNC, Node-B

Description

Method and apparatus for allocating communication frequency for inducing even multi-frequency distribution in WCDMA system

1 is a view for explaining a phenomenon in which a particular frequency is particularly assigned to mobile terminals according to the prior art.

2 is a view for explaining a WCDMA system according to an embodiment of the present invention.

3 is a diagram for explaining that multiple frequencies are uniformly allocated to mobile terminals according to an embodiment of the present invention.

4 is a flowchart illustrating a method of allocating communication frequencies to induce an even distribution of multiple frequencies in a location registration process according to an embodiment of the present invention.

5 is a diagram for describing a communication frequency allocation method using a round robin method.

6 is an example for explaining a communication frequency allocation method using a random function in operation of two FAs.

7 is an example for describing a communication frequency allocation method using a random function in four FA operations.

8 is a view for explaining an example of the RNC implementing the communication frequency allocation method according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

MS: Mobile Station

RAN: Radio Access Network

RNC: Radio Network Controller

Node-B: Base Station

The present invention relates to a wideband code division multiple access (WCDMA) system, and more particularly, in a WCDMA system in which a multi-frequency allocation (FA) cell (base station) is operated, during a location registration process of a mobile terminal, RRM (Radio Resource Management) The present invention relates to a communication method and apparatus for a WCDMA system capable of distributing a location registration load by inducing an even distribution of multiple FAs by assigning a communication frequency of a mobile terminal in various ways such as a random function method without interworking .

In general, in cellular mobile communication such as CDMA and WCDMA, there is a capacity limitation in serving a subscriber on one frequency, so it is often impossible to fully accommodate a subscriber on one frequency channel, such as in a densely populated area of a large city. Occurs. In these regions, it is exceptionally operated as a multi-FA which serves as 1FA, 2FA, 3FA, and 4FA by adding two or more frequency channels, for example, four channels in addition to the basic channel.

In the cell in which the multiple FAs are operated, frequency allocation that determines which FA the mobile station communicates with during cell search is a problem.

In case of CDMA system, channel Hashing algorithm is performed by using channel information from the network and its unique number, IMSI (International Mobile Station Identity) to select appropriate frequency and perform location registration process to the corresponding FA. Camping

On the other hand, in the case of a WCDMA system, the RAN (Radio Access Network) side may take a method of directly selecting a FA, and load is distributed through RRM (Radio Resource Management). Accordingly, the quality of the strongest signal, for example, a common pilot channel (CPICH), and the like through slot synchronization, frame synchronization, and PN (Pseudo Noise) code identification in the mobile terminal. A FA having the best strength can be selected, and based on this, camping with the FA can be performed by performing a location registration process after determining the validity of the cell.

However, in the conventional frequency allocation scheme when searching for a cell in a WCDMA cell in which multiple FAs are operated, the load is not evenly distributed among the multiple FAs, and as shown in FIG. For example, it may be excessively driven by 2FA. That is, in the case of WCDMA, camping can be focused on the FA of the strongest signal, and it is difficult to distribute the mobile terminals evenly among the multiple FAs by performing RRM for a short time in the initial location registration process. Accordingly, even in actual call connection settings such as voice data or packet data, communication failures such as access collision and call setup time delay may occur due to an increase in load on a specific FA. In addition, even if the call setup is made, the quality of service (QoS) deterioration due to signal interference of the same frequency is concerned, and even if RRM is performed and resource distribution is performed, the quality of service of other users who made the call setup, in particular, a lien right There is a problem that (pre-emption) may be degraded.

Accordingly, an object of the present invention is to solve the above-described problem, and an object of the present invention is to provide an access collision of mobile terminals due to an increase in load on a specific FA during call connection establishment in a WCDMA system in which cells of multiple FAs are operated. In order to prevent the causes of communication failures such as access collision or call setup time delay in advance, even distribution of multiple FAs is induced by assigning a communication frequency of a mobile terminal in various ways such as a random function method during location registration. To provide a frequency allocation method and apparatus that can distribute the location registration load.

In addition, another object of the present invention, in the WCDMA system in which the cells of multiple FAs are operated, induces the mobile terminals to be distributed evenly among the multiple FAs during the initial location registration process to distribute the cell load so that subscribers are not attracted to a specific FA and overall The present invention provides a method and an apparatus for allocating frequencies to improve the stability of a system.

In addition, another object of the present invention is to induce a load balance of a cell in an idle state in a WCDMA system in which cells of multiple FAs are operated, thereby overloading a cell load that may be excessively driven during initial call setup. It is to provide a frequency allocation method and apparatus that can be prematurely distributed and actively prevent degradation of service quality due to excessive cell load.

According to an aspect of the present invention for achieving the above object of the present invention, a method for allocating a communication frequency of a mobile terminal in a wireless communication system operating multiple frequency allocation (FA), receiving a message; And determining frequencies by sequentially selecting or randomly selecting each FA in response to the received message.

According to another aspect of the present invention for achieving the above object of the present invention, a method for allocating a communication frequency of a mobile terminal in a wireless communication system for operating a medium frequency (FA), receiving a message; And determining a frequency by selecting any one of multiple FAs regardless of the signal strength of the FA used in the received message.

According to another aspect of the present invention for achieving the above object of the present invention, a method for allocating a communication frequency of a mobile terminal in a wireless communication system operating multiple frequency allocation (FA), connection request for location registration Receiving a (Connection Request) message; Calculating an FA value in response to the connection request message; And transmitting a connection setup message in which the FA value is designated, wherein a communication frequency corresponding to the FA value is used for location registration of the mobile terminal according to the connection setup message.

According to another aspect of the present invention for achieving the above object of the present invention, a wireless communication system for operating multiple frequency allocation (FA), each FA sequentially in response to the received message using the message receiving means RNC for repeating the selection or randomly selecting the frequency to determine the frequency, and after the RNC determines the frequency, according to the message transmitted through the message transmission means, the determined frequency is in the idle state registration process of the mobile terminal. It is characterized by being used.

According to another aspect of the present invention for achieving the above object of the present invention, a wireless communication system for operating multiple frequency allocation (FA), the signal of the FA used for each message received by using a message receiving means The RNC selects one of the multiple FAs regardless of the strength to determine a frequency, and the mobile station in the idle state registers the location using the determined frequency.

According to another aspect of the present invention for achieving the above object of the present invention, a wireless communication system for operating multiple frequency allocation (FA), the message receiving unit for receiving a connection request (Connection Request) message for location registration ; A FA distribution unit for calculating an FA value in response to the connection request message; And a message transmission unit configured to transmit a connection setup message in which the FA value is designated, wherein a communication frequency corresponding to the FA value is used to register the location of the mobile terminal according to the connection setup message. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited to the embodiments. Like reference numerals in the drawings denote like elements.

2 is a diagram illustrating a WCDMA system 200 according to an embodiment of the present invention. Referring to FIG. 2, the WCDMA system 200 according to an embodiment of the present invention may include a mobile station (MS) 210, a radio access network (RAN) 220, and a core network (core). network (CN) 230. In addition, the WCDMA system 200 is connected to the core network 230, a home location register (HLR) 240 for managing location registration and status of subscriber stations, and various application servers 250 for providing multimedia services. ) May be further included.

The RAN 220 includes a base station (Node-B) and an RNC (Radio Network Controller) controller 221. The base station Node-B connected to the RNC 221 may be configured in plural, and the mobile terminal 210 receives a relay of the base station Node-B, such as a call, digital broadcast, digital media streaming, download and upload, and the like. Receive communication services. The RNC 221 connected between the base station Node-B and the core network 230 controls the traffic generated in the communication to be transmitted and received to the destination through the base station Node-B. The RNC 221 controls a communication between the mobile terminals 210 by performing a Radio Resource Management (RRM) function according to the scheduling of radio resources and a handoff function supporting mobility between cells, thereby controlling circuit traffic. traffic or IP (packet traffic) packet traffic (IP) packet traffic (packet traffic), etc. can be appropriately transmitted and received to the destination mobile terminal, landline phone, application server, and the like.

On the other hand, the mobile terminal 210 is a camping (WCDMA) network in the network (camping) is a comprehensive meaning of all kinds of wireless communication device using the WCDMA access technology. The mobile terminal 210 periodically communicates with the RAN 220 even in an idle state to perform a location registration process with the HLR 240 connected to the core network 230. After the location registration is made, call connection setting, for example, call, data streaming, downloading or uploading, etc. may be performed using the frequency determined at the time of location registration, and the RRM of the RNC 221 is interlocked even during the actual call connection. The process of distributing resources so that the load can be distributed can be performed.

In the present invention, the mobile terminal when the WCDMA system 200 operates a multi-FA cell (base station) scheme in a case where the subscriber cannot be sufficiently accommodated in one frequency channel, such as an area with high population density in a large city. The load during the location registration process of 210 is to be distributed.

In the WCDMA system 200 that operates multiple frequency allocation (FA), when the mobile station 210 performs the location registration process, as described above, as described above, the RRM function is performed in the initial location registration process. Since it is difficult to obtain an even frequency distribution over time, in the present invention, the RNC 221 performs various fast frequency determination methods for inducing even distribution of frequencies without performing RRM in the location registration process. 210 to determine the communication frequency with.

That is, the RNC 221 receives a message from the mobile terminal 210 by using a predetermined message receiving means in the position registration process of the mobile terminal 210 in the idle state, regardless of the signal strength of the FA used for each message. In order to determine the frequency by repeatedly selecting each FA sequentially or random frequency determination method by selecting one of the multiple FA, for example, 1FA, 2FA, 3FA, 4FA to the frequency for communication with the mobile terminal 210 Decide Accordingly, after the RNC 221 determines the frequency as described above, the mobile terminal 210 performs the location registration process using the determined frequency according to the message transmitted through the predetermined message transmission means.

As such, a method of determining frequencies by repeatedly selecting each FA sequentially, for example, a round robin method or a random frequency determination method, for example, a method using a random number generation function By assigning a FA or a frequency to the mobile terminals by using a temporary mobile subscriber identifier (TMSI), and a TMSI (Temporary Mobile Subscriber Identifier) as a variable of the random number generation function, as shown in FIG. The location registration load can be distributed by early derivation so as to distribute it evenly among the multiple FAs. In this way, since the load balance of the cell is induced early in the idle state of the mobile terminals, the cell load is prematurely distributed at the time of call connection so that a particular FA is not excessively used, resulting in an increase in load on a specific FA. It is possible to prevent the causes of communication failures such as access collision or call setup time delay of mobile terminals in advance, thereby contributing to the improvement of overall system stability and quality of service.

Hereinafter, a method of allocating communication frequencies to induce an even distribution of multiple frequencies in a location registration process according to an embodiment of the present invention will be described in more detail with reference to the flowchart of FIG. 4.

Referring to FIG. 4, first, an idle mobile terminal 210 transmits a Radio Resource Control (RRC) Connection Request message for location registration to the RNC 221 (S410). The RRC connection request message includes 'Establishment Cause' among User Equipment (UE) information elements, and requests a location registration request by a code for 'Registration', for example, 5 bits, in 'Establishment Cause'. You can check it. In addition, when the actual call is connected, 'Establishment Cause' may include codes such as 'Conversational Call', 'Streaming Call', and 'Interactive Call'.

Next, the RNC 221 receiving the RRC connection request message repeatedly selects each FA sequentially to determine the frequency or random frequency determination method irrespective of the signal strength of the FA used in the message. Calculate (S420). The FA value may be, for example, a value representing any one of 1FA, 2FA, 3FA, and 4FA, and a frequency of a predetermined WCDMA bandwidth is assigned to each FA. Here, the number of FAs is illustrated as four, but the present invention is not limited thereto, and the number of FAs may be less than or more than enough to accommodate a subscriber.

In order to distribute the FA evenly to the mobile terminals 210, a method of determining frequencies by repeatedly selecting each FA sequentially or a random frequency determining method may be variously used. For example, as shown in FIG. 5, a round robin scheme may be used in which priority is assigned to each of the multiple FAs sequentially so that corresponding FA values are sequentially assigned whenever an RRC connection request message is received.

Alternatively, a method of randomly determining frequencies may be used. For example, as shown in FIG. 6, when two FAs are in operation, each random selection is made by selecting one of A and B for FAs by a random number generation function. By assigning the FA value corresponding to the multiple FAs can be distributed evenly distributed to the mobile terminals (210). In addition, when three or more FAs are used, the random number generation function may be used once as described above, but for more random selection, the FA value may be given by using the random number generation function twice as shown in FIG. 7. have. For example, as shown in FIG. 7, when four FAs are operated, a process of selecting any one of A and B, and a process of selecting one of two a and b, or c For example, a random number generation function may be used in each process including selecting one of two types, d.

In addition, as another example of randomly determining a frequency, Temporary Mobile Subscriber Identifier (TMSI) may be used as a variable of a random number generation function. TMSI is information transmitted from the mobile terminal 210 for authentication at the time of location registration or call connection, and may be used as a variable of a predetermined random number generation function indicating a uniform distribution of a corresponding code value.

As a more specific example of randomly determining frequencies, a hash key can be generated to evenly distribute FA values for RRC connection request messages. For example, if the hash key is defined as 32 bits, all of the upper 16 bits may be '0', and the remaining 16 bits may be configured by adding TMSI. At this time, by calculating the FA_selecton function defined as shown in [Equation 1], it is possible to give the FA value using this. In [Equation 1], N is the number of FAs currently operating in the base station (Node-B), L is the number of the upper 8 bits are all configured as '0', the remaining 8 bits are composed of the lower 8 bits of TMSI, L is the upper All 8 bits are set to '0', and the remaining 8 bits are composed of the upper 8 bits of TMSI, and DECORR is a number resulting from a constant function using the hash key as a variable. When FA_selecton is determined to be 12 bits according to [Equation 1], by taking mod N, the corresponding FA value can be determined. Herein, the hash key, L, H, and DECORR values have been described by way of example, but are not limited thereto, and these variables may be used in other arbitrary numbers.

[Equation 1]

N * ((40503 * (L

H

DECORR)) mod 2¹⁶) /2¹⁶

FA_selecton =

N * ((40503 * (L

H

DECORR)) mod 2 ¹⁶ ) / 2 ¹⁶

In the above, some examples of randomly determining frequencies have been described. However, the present invention is not limited thereto, and various other methods of rapidly determining FA and moving the FA balance early without RRM interworking may be used. Can be.

In the FA value determination process, the RNC 221 may calculate the FA value based on its own system without distinguishing the base station Node-B receiving the RRC connection request message, or the base station receiving the RRC connection request message ( Node-B) may be classified by repetitively selecting the respective FAs sequentially for each base station to determine a frequency or a random frequency determination method, that is, the FA value may be calculated based on the base station. The division of the base station (Node-B) may be made by confirming a predetermined identification code from a signal transmitted and received with the mobile terminal 210 during cell search.

As described above, after calculating the FA value, the RNC 221 transmits a Radio Link Setup request message for establishing a radio link to a corresponding Node-B communicating with the mobile terminal 210. (S430). Accordingly, the base station Node-B performs a radio link for communicating with the mobile terminal 210, that is, a corresponding channel setup, and sets up a RL in response to the RL setup request message. ) The response message is notified to the RNC 221 (S440). At this time, in step S430, the RRL (Radio Link Setup) request message is preferably included in the FA value calculated by the RNC 221 in step S420. This is to allow the base station Node-B to establish a wireless channel link for communicating with the mobile station 210 at a corresponding frequency corresponding to the FA value.

As such, when the radio link setup is completed, the RNC 221 transmits an RRC (Radio Resource Control) connection setup message to which the FA value is specified (S450). The RRC Connection Setup message includes 'Frequency info' among Physical channel information elements and includes a 'Frequency info' for downlink or uplink in 'Frequency info'. Code that specifies the frequency and contains the FA value.

As such, when the mobile terminal 210 is notified of the RRC connection setup message transmitted from the RNC 221, the mobile terminal 210 communicates with the core network 230 using a communication frequency corresponding to the FA value to perform a location registration process. The current location of the mobile terminal 210 is registered in the HLR 240 by the location registration process, and thus, a quick call through the base station Node-B to which the mobile terminal 210 belongs when an actual call connection request occurs. The location of the mobile terminal 210 is managed to make a connection.

Communication frequency allocation method according to an embodiment of the present invention as described above can be implemented by including the configuration shown in Figure 8 in the RNC (800). Referring to FIG. 8, the RNC 800 according to an embodiment of the present invention may include a message receiver 810, a FA distributor 820, a storage unit 821 for managing a FA list, and a message transmitter 830. It may include.

The message receiver 810 receives a Radio Resource Control (RRC) Connection Request (RRC) Connection Request message for location registration from the mobile terminal 210. The RRC connection request message includes a 'Establishment Cause', and the message receiver 810 activates the FA distribution unit 820 when the 'Establishment Cause' includes a 5-bit code for 'Registration'.

As such, the FA distributing unit 820 is activated according to the RRC connection request message including a 5-bit code for 'Registration', and the scheme as shown in FIGS. 5 to 7 or Equation 1 as described above. That is, irrespective of the signal strength of the FA used in each message, the FA values for frequency determination may be determined by repeatedly selecting each FA of the multiple FAs one by one, or by random FA selection using a random number generation function or a hash key. Calculate The FA distributing unit 820 may refer to the FA list for each base station managed by the storage unit 821 in the form of a register or a predetermined memory.

The FA distributing unit 820 may calculate the FA value based on its own system without distinguishing a base station Node-B that receives an RRC connection request message, or receives a base station that receives an RRC connection request message. By dividing B), the FA value may be calculated by the frequency determination method as described above for each base station.

When the FA value is determined by the FA distribution unit 820, the message transmitter 830 requests a RL setup for establishing a radio link to a corresponding Node-B communicating with the mobile terminal 210. Send a message. As described above, the RL setup request message may include an FA value, and thus, the base station Node-B establishes a radio link for communicating with the mobile terminal 210, that is, a corresponding channel setup. In response to the RL Setup (Radio Link Setup) request message, the RL Setup (Radio Link Setup) response message is notified.

In addition, the message transmitter 830 transmits an RRC connection setup message in which the FA value is designated to the mobile terminal 210. As described above, the RRC connection setup message is transmitted with a FA value as a code specifying a frequency for a downlink or an uplink in 'Frequency info'. Accordingly, the mobile terminal 210 performs a location registration process by communicating with the core network 230 using a communication frequency corresponding to the FA value.

The functions used in the methods and apparatus disclosed herein can be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). do. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

As described above, in the method and apparatus for frequency allocation in a WCDMA system in which cells of multiple FAs operate according to the present invention, an even distribution of multiple FAs is provided by allocating a communication frequency of a mobile terminal in various ways during a location registration process. By spreading the location registration load by deriving, it is possible to prevent causes of communication failures such as access collision or call setup time delay of mobile terminals due to an increase in load on a specific FA during call connection establishment.

In addition, in the WCDMA system in which multiple FA cells operate according to the present invention, the method and apparatus for frequency allocation distribute cell loads so as not to be concentrated in a specific FA by inducing mobile terminals to be distributed evenly among multiple FAs during an initial location registration process. By doing so, the stability of the overall system can be achieved.

In the WCDMA system in which multiple FA cells operate according to the present invention, a frequency allocation method and apparatus induce an early load balance of a cell in an idle state, thereby allowing cell load during initial call setup. It is possible to prevent the deterioration of the quality of service proactively by distributing it early so that the specific FA is not excessively used.

Claims (18)

A method of allocating a communication frequency of a mobile terminal in a wireless communication system that operates multiple frequency allocation (FA), Receiving a message; And And sequentially reselecting or randomly selecting each FA in response to the received message to determine a frequency. And the determined frequency is used for the location registration process of the mobile terminal in the idle state. A method of allocating a communication frequency of a mobile terminal in a wireless communication system that operates multiple frequency allocation (FA), Receiving a message; And Determining a frequency by selecting any one of multiple FAs regardless of the signal strength of the FA used in the received message, And the determined frequency is used for the location registration process of the mobile terminal in the idle state. A method of allocating a communication frequency of a mobile terminal in a wireless communication system that operates multiple frequency allocation (FA), Receiving a Connection Request message for location registration; Calculating an FA value in response to the connection request message; And Transmitting a connection setup message to which the FA value is assigned; Including, And a communication frequency corresponding to the FA value is used for location registration of the mobile terminal according to the connection setup message. The method of claim 3, wherein calculating the FA value comprises: And determining the FA value by repeatedly selecting or randomly selecting each FA. The method of claim 3, wherein calculating the FA value comprises: A round robin method for selecting any one of the multiple FAs, a method using a random function, and a method using a Temporary Mobile Subscriber Identifier (TMSI) as a variable of a predetermined function Frequency allocation method. The method of claim 3, wherein calculating the FA value comprises: Computing the FA value without distinguishing the Node-B receiving the connection request message, or calculating the FA value in a separate manner for each base station by distinguishing the base station receiving the connection request message. Frequency allocation method comprising a. The method of claim 3, wherein before transmitting the connection establishment message, Sending a message for radio link setup to the base station Frequency allocation method comprising a. 8. The method of claim 7, wherein the message for establishing a radio link includes the FA value. The frequency allocation method according to any one of claims 1 to 8, which is used in a WCDMA system. delete In a wireless communication system that operates multiple FA (Frequency Allocation), RNC for determining the frequency by sequentially selecting or randomly selecting each FA in response to the message received by the message receiving means, And after the RNC determines the frequency, the frequency is used for a location registration process of a mobile terminal in which the determined frequency is in an idle state according to a message transmitted through a message transmitting means. In a wireless communication system that operates multiple FA (Frequency Allocation), RNC for determining a frequency by selecting any one of the multiple FA regardless of the signal strength of the FA used for each message received by using the message receiving means, And a mobile station in an idle state registers a location using the determined frequency. In a wireless communication system that operates multiple FA (Frequency Allocation), A message receiver for receiving a connection request message for location registration; A FA distribution unit for calculating an FA value in response to the connection request message; And Message transmission unit for transmitting a connection setup message with the FA value specified Including, And a communication frequency corresponding to the FA value is used for location registration of a mobile terminal according to the connection setup message. The method of claim 13, wherein the FA dispersion unit, And repeatedly selecting or randomly selecting each FA to determine the FA value. The method of claim 13, wherein the FA dispersion unit, Wireless communication, characterized in that the FA value is calculated without distinguishing a base station (Node-B) receiving a connection request message or the base station receiving a connection request message is calculated in a separate manner for each base station. system. The method of claim 13, wherein the message transmission unit, And transmitting a message for radio link setup to a base station before transmitting the connection establishment message. 18. The system of claim 16 wherein the message for establishing a radio link includes the FA value. The wireless communication system according to any one of claims 13 to 17, wherein A wireless communication system characterized by being a Radio Network Controller (RNC) of a WCDMA system.

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