KR100250444B1 - Position registering method using the counter of mobile terminal and id memory device of visiting cell - Google Patents

Abstract

PURPOSE: A location registration method of a mobile communication exchange system is provided to simplify a structure, and to decrease a traffic load by deciding a cell performing a location registration through mobility and a call arrival rate of a mobile terminal. CONSTITUTION: An identifier of a cell into which a mobile terminal goes is compared to stored identifiers of visited cells(102,103). If there is not the identifier of the cell into which the mobile terminal goes in the identifiers of the visited cells, a counter of a mobile terminal is increased by one, and the counter is compared to a mobile threshold (104,105). When the counter of the mobile terminal is more than the mobile threshold, a location registration is performed at the cell into which the mobile terminal goes, and the mobile threshold of a pertinent terminal is updated(106). When the counter of the mobile terminal is less than the mobile threshold, the identifier of the cell into which the mobile terminal goes, is added to a visiting cell identifier storing device(107).

Description

Location registration method of mobile communication exchange system using counter in mobile terminal and storage device of visiting cell

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellular mobile communication system, and more particularly to a mobile communication switch (IMT-2000) using an identifier storage device of a counter and a visited cell in a mobile terminal for simple and efficient location management of a mobile terminal using paging and location registration. The present invention relates to a location registration method of a system.

In general, location management uses the concept of a location area (LA) and a paging area. That is, the mobile switching service divides the area serviced into a plurality of cell units, defines each as a location area, and then performs location registration when the mobile terminal enters a boundary of an adjacent location area. In addition, in the case of a mobile terminal incoming call, the location area where the location registration is performed is divided into a plurality of paging areas, and then each of them is sequentially or temporarily paged.

In order to establish an incoming call to a mobile terminal that is moving, it is necessary to find out the base station where the mobile terminal is located. The simplest method of locating the mobile terminal is to find the position of the mobile terminal by transmitting a paging signal to the entire mobile system and receiving a response signal from the mobile terminal. In this case, every time an incoming call is received by the mobile terminal, the entire page of the mobile communication system must be paged, so the cost of the page is huge. Therefore, the conventional location management method divides the entire area of the mobile system into several location areas, and then performs location registration whenever the mobile terminal enters an adjacent location area, and then performs location registration when an incoming call is received by the corresponding mobile terminal. I'm using a method of paging one location area. However, such a conventional location management method is difficult to configure the location area and can not flexibly cope with the amount of traffic, and does not reflect the characteristics of each mobile terminal.

Accordingly, the present invention provides a method for setting the number of cell boundaries that can move without performing location registration based on the mobility of each mobile terminal and the incoming call arrival rate of the mobile terminal, and is unnecessary when the mobile terminal moves back and forth from the cell boundary. It is an object of the present invention to provide a method for registering a location of a mobile communication switchgear system that enables simple and efficient location management of a mobile terminal by using a method for preventing location registration.

In order to achieve the above object, the present invention provides a first step of initializing a mobile threshold when power is supplied to a mobile terminal, and when the mobile terminal crosses a cell boundary and enters an adjacent cell, A second step of checking whether or not the mobile terminal is present in the visited cell identifier storage device; if the identifier of the cell to enter exists, terminates; and if there is no identifier of the cell to enter, After increasing the counter by 1, the third step of comparing the counter and the size of the mobile threshold; and when the counter of the mobile terminal exceeds the mobile threshold as a result of the comparison, the location registration is performed in a newly entered cell, and [ A fourth step of terminating and then setting a new mobile threshold value of the corresponding terminal using Equation 3; And if the counter is less than or equal to the mobile threshold, a fifth step of adding an identifier of a newly entered cell to the visited cell identifier storage device of the mobile terminal and ending.

Where α (j): incoming call arrival rate, ρ _k : probability that the mobile terminal exists in area A, w _k : number of cells to be searched until the mobile terminal is found, U: cost of location registration (about 10 paging costs) Times), V: the cost of paging.

1 is a flowchart showing the performance of location registration using a counter and a storage cell of a visited cell in a mobile terminal.

The mobile communication system is a mobile terminal (MT), a base system (BS), a control station (Basestation Controller (BSC)), a control station operation management device (Basestation Manager: BSM), a mobile switching center (Mobile Exchange: MX). ) And Home Location Register (HLR).

The mobile terminal (ML) processes a radio signal received from a base station with four correlation detectors, one of which is a search receiver and searches for a pilot signal transmitted from an adjacent base station and obtains it based on the carrier phase of the nearest base station. The search receiver determines a strong signal path among the signals received in the handoff region. The other correlation detector is a digital data receiver, and correlates signals received in the multipath detected by the search receiver with a corresponding pseudo noise sequence.

The base station (BS) transmits and receives subscriber information and is in charge of wireless connection with the mobile terminal and wired and wireless connection with the control station. A base station consists of a channel element (CE), a base station interconnection network, and a radio frequency transceiver (RF). The channel element (CE) is responsible for code division multiple access device (CDMA) channel coding / decoding, sector-by-sector interface, performing analog common functions for modulation / demodulation, receiving reference time and frequency information, and distributing and supplying functions. The base station interconnection network is responsible for transmitting and receiving control and traffic information with the control station via the relay line E1. Radio frequency transmitters and receivers are responsible for low noise, high power amplification, band filtering of transmit and receive signals, frequency conversion, and signal combining and distribution for multiple frequency assignments.

The control station (BSC) is located between the base station and the telephone exchange station, controls the base station, and handles power control and handoff of the mobile terminal. In the base station, a transcoding selector bank (TSB) and a call control processor (CCP) are connected through a CDMA interconnection network (CIN).

The control station BSC collects various types of information about failures, statuses, statistics, etc. of the base station and the control station, and performs each subsystem operation management and maintenance function. The control station operation preservation system duplicates commercial workstations (line stations) through high level data link control (HDLC) port redundancy and matching mode redundancy to operate and maintain the entire alarm collection and alarm processing base station. It was used for maintenance control, base station program loading, and operator matching.

The mobile telephone switching center (MX) is composed of the switching center and the visitor location register (VLR). The switching center is responsible for call processing for subscribers and interworking and operation management between the public telephone network (PSTN) and the wireless subscriber network. The location register is responsible for a database function located in the mobile switching center that stores location information for the subscriber.

The home location register (HLR) performs a central database function for storing temporary information such as permanent information about the subscriber registered in the digital mobile communication network and the current location information of the subscriber.

The procedure for setting an incoming call of a mobile terminal in a mobile communication system is performed in the following order.

First step; Contact the home location register for the mobile switching center where the mobile terminal is located via No.7 signaling network.

Second step; The communication channel transmitted from the home location register is used to establish a communication channel between the mobile switching center and the telephone network.

Third step; The mobile switching center sequentially performs paging on the cell where the mobile station last performed location registration.

Fourth step; The receiving mobile terminal receiving the paging signal transmits a response signal to the base station to perform call setup of the wireless section between the mobile terminal and the mobile switching center.

The present invention relates to a method for minimizing the cost of location management of a mobile terminal. Location management of the mobile terminal is performed by location registration and paging mechanism. Location registration uses a reverse link between a base station and a mobile terminal to inform the mobile communication system of an identifier of a base station of a cell to which the mobile terminal enters when the mobile terminal moves outside a predetermined boundary. When the mobile terminal moves inside the visited location register, only the contents of the database of the visited location register are changed.However, when the mobile terminal moves to an adjacent visited location register, the fact is reported to the home location register using the No.7 signal line. Change the contents of the current visit location register and the database of the adjacent visit location register. Paging is performed by first paging the cell that performed the last location registration as the central cell, then paging the neighboring cell surrounding the central cell, and then sequentially paging the next neighboring cell. Use forward links. The cost of location management is determined by the sum of the costs of location registration and paging.

In addition, the present invention obtains a mobile threshold value that minimizes the cost of location management by the mobility and the incoming call arrival rate of the mobile terminal to perform location registration in the cell entering each time the mobile terminal exceeds the mobile threshold, and location Paging is performed first using the last cell to be registered as a center cell, then paging a layer 1 neighboring cell surrounding the center cell, and then paging a layer 2 neighboring cell surrounding the 1 layer cell. The invention is about location management. The mobile threshold is the number of cell boundaries that the mobile terminal can cross the cell boundary without performing location registration. The mobile threshold value is determined for each mobile terminal by a value d, which minimizes the location management cost of Equation 2 below.

Where α (j) is the incoming call arrival rate,

ρ _k : probability that a mobile terminal exists in area A,

w _k : the number of cells to search until the mobile terminal is found,

U: cost of location registration (about 10 times paging fee),

V: the cost of paging.

The moving threshold value (d) obtained in Equation 2 refers to the number of boundaries of cells crossing when the mobile terminal moves in one direction from the center cell. However, location registration is unnecessary when the mobile terminal crosses the cell boundary and exceeds the mobile threshold. In order to prevent such unnecessary location registration, the present invention uses a counter indicating the number of cell boundaries that intersect a space capable of storing a certain number of cell identifiers in the mobile terminal. Therefore, when the mobile terminal crosses the cell boundary, it is determined whether the cell's identifier is already stored in the cell, and if it is a new cell, the counter is increased and the identifier of the cell is stored in the mobile terminal.

The location management procedure of the present invention can be divided into a location registration procedure and a paging procedure. First, the location registration procedure is as follows.

First step; When power is supplied to the mobile terminal, the first mobile threshold value is set to 2 and the counter is set to 1, and the identifier of the corresponding cell is stored in the mobile terminal.

Second step; When the mobile terminal crosses the boundary of the adjacent cell, it compares the identifier of the cell with the identifier of the cell stored in the mobile terminal.

Third step; As a result of the comparison in the second step, in the case of the identifier of the new cell not stored in the mobile terminal, the counter is increased by one, and after determining whether the value of the counter exceeds the mobile threshold value, the process proceeds to the fourth step.

Fourth step; If the value of the counter does not exceed the mobile threshold, the identifier of the cell is stored in the mobile terminal.

A fifth step; If the value of the counter exceeds the mobile threshold, location registration is performed, the memory space of the cell identifier of the mobile terminal is initialized, and the mobile threshold is calculated based on the current incoming call equation (Equation 2). Going to the stage

Sixth step; As a result of the comparison in the second step, when the identifier of the cell stored in the mobile terminal is determined as the cell boundary is operated, the value of the counter is not increased.

The paging procedure is as follows.

First step; Paging is performed first using the cell where the location registration was last performed as the center cell.

Second step; If the mobile station does not exist in the center cell, the adjacent 1 layer cell surrounding the center is paged.

Third step; If the mobile terminal does not exist in the adjacent layer 1 cell, the layer 2 cell surrounding the layer 1 cell is paged.

Fourth step; In the same manner as in the second and third steps, the range of paging is extended until the corresponding mobile terminal is found in adjacent cells of the next layer.

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

Figure 1 shows a flow chart for performing the location registration by the mobility of the mobile terminal.

When power is supplied to the mobile terminal, the first mobile threshold value is set to 2 (101). When the mobile terminal crosses the cell boundary and enters the neighboring cell, it compares the identifier of the entering cell with the identifiers of already visited cells stored in the visited cell identifier memory of the mobile terminal (102 and 103). This is to select a case where the mobile terminal is operated at the boundary of the cell. As a result of the comparison, when the cell is not previously visited, the counter of the mobile terminal is increased by 1, and then the counter and the mobile threshold are compared (104 and 105). If the counter of the mobile terminal exceeds the mobile threshold, the location registration is performed in the newly entered cell, and the mobile threshold of the corresponding terminal is newly set using Equation 2 (106). It also initializes the visited cell identifier memory of the mobile terminal. If the counter of the mobile terminal is less than or equal to the mobile threshold, the identifier of the newly entered cell is added to the visited cell identifier storage of the mobile terminal (107). If the cell has been previously visited, the procedure ends.

As described above, the present invention calculates the mobile threshold d using Equation 2 in consideration of the mobility, the incoming call, the arrival rate and the paging area of the mobile terminal for each mobile terminal, and then the mobile terminal determines the mobile threshold value. Location registration may be performed when crossing the cell boundary beyond.

In the conventional location registration method by location area, since the size of the location area needs to be redesigned as the cell size is changed, the design cost is high, and a complex algorithm is used to consider the mobile terminal operating at the boundary of the location area. This increases the load on the system.

On the other hand, as described above, according to the present invention, since the cell to perform location registration is determined by the mobility and call arrival rate of each mobile terminal, the implementation is simple and reduces the traffic load required for location management imposed on the mobile system. Has an excellent effect.

Claims (1)

A first step of initializing a mobile threshold when power is supplied to the mobile terminal, When the mobile terminal crosses a cell boundary and enters an adjacent cell, a second step of checking whether an identifier of the entering cell exists in the visited cell identifier storage of the mobile terminal; Terminating if there is an identifier of the cell to be entered as a result of the checking; if the identifier of the cell to be entered does not exist, increasing the counter of the mobile terminal by 1 and then comparing the counter with the size of the mobile threshold; Wow, If the counter of the mobile terminal exceeds the mobile threshold as a result of the comparison, the fourth step of performing a location registration in the newly entered cell, and after setting a new mobile threshold of the corresponding terminal using Equation 3 below: Wow, And if the counter of the mobile terminal is less than or equal to the mobile threshold as a result of the comparison, adding a new cell identifier to the visited cell identifier storage device of the mobile terminal and ending the fifth step. And a location registration method of a mobile communication exchange system using an identifier storage device of a visiting cell. Where α (j) is the incoming call arrival rate, ρ _k : probability that a mobile terminal exists in area A, w _k : the number of cells to search until the mobile terminal is found, U: cost of location registration (about 10 times paging fee), V: the cost of paging.