KR20010068446A - The Mobile Subscriber Roaming Control of CDMA WPBX/Keyphone System - Google Patents

Abstract

PURPOSE: A subscriber roaming control method of a CDMA(Code Division Multi Access) wireless PBX(Private Branch Exchange)/keyphone system is provided to construct the CDMA wireless PBX/keyphone system in a service region as an overlay cell. CONSTITUTION: A mobile terminal receives a pilot channel signal(2) transmitted to a CDMA(Code Division Multi Access) wireless PBX(Private Branch Exchange)/keyphone system by a larger determined level than a level of a pilot channel signal(1), and is turned into an idle hand off(3). The mobile terminal transmits a location register requesting message(4) when a part of location register related to parameters are changed. A system controller receiving the location register requesting message transmits a location register responding message(6) and a channel assigning message(7) if the mobile terminal is a home subscriber(5). The system controller transmits the only location register responding message when the location register requesting message is received from the outer subscriber. If a receiving call for the home subscriber(5) is generated, the system controller converts the receiving call into an inner calling message(9) of the CDMA wireless PBX, and transmits the inner calling message(9) to the mobile terminal. A channel converting commander induces the idle hand off from a mobile communication network base station to the CDMA wireless PBX.

Description

Subscriber roaming control method of CDM wireless private branch exchange / keyphone system {The Mobile Subscriber Roaming Control of CDMA WPBX / Keyphone System}

In the situation where CDMA mobile communication service has been widely popularized, attempts have been made to provide a communication service using a mobile communication network in a public area, and to communicate through the same CDMA cellular terminal and a PCS terminal in a private area such as an office. To this end, products with the concept of extending the service area of a mobile communication network by installing an optical repeater for relaying a base station signal of a mobile communication network to a predetermined area, or by installing a base station directly connected to the mobile communication switch, including a voice encoder, in a building It is used. In case of providing communication service through CDMA cellular terminal and PCS terminal in private area such as office by using optical repeater or base station of mobile communication network, roaming control is provided as part of mobile network operation function, but optical relay or base station is used in private area Installation is determined by the economic interests of the mobile operator and may not be installed at any time by the general user. Even if these products are installed in the office, not only all the communication generated inside the company, but also the landline telephone network incoming call will go through the mobile communication network, so communication costs are excessive and cannot be a means of replacing the landline telephone in the office.

The present invention provides a CDMA wireless private branch exchange / keyphone system, which serves as a private base station to compensate for the disadvantages of the prior art, as an overlapping cell in a service area of a mobile communication network base station, by using a conventional CDMA cellular terminal and a PCS terminal. A private base station accommodates incoming and outgoing service from wired telephone network access service and mobile communication network as well as internal system call service. In addition, roaming control provided as an operation function in a mobile communication network is effectively performed in a CDMA wireless private exchange / keyphone system.

When the home subscriber moves between the service area of the mobile communication base station and the service area of the CDMA wireless private exchange / keyphone system, the CDMA frequency channel switching is automatically performed without user intervention. On the other hand, the external subscriber controls the roaming of the user to directly access the mobile communication network base station without using the service of the CDMA wireless private exchange / keyphone system.

-. 1 is an overlapping cell configuration configured by a CDMA wireless private exchange / keyphone system to support roaming of subscribers.

-. 2 is a block diagram of a roaming control function of a CDMA wireless private exchange / keyphone system

-. 3 is a procedure for changing a CDMA frequency channel of a home subscriber roaming to a service area of a CDMA wireless private exchange / keyphone system.

In order to achieve the above object, an embodiment of a roaming control method according to the present invention used in a CDMA wireless private exchange / keyphone system will be described in detail.

1 shows the shape of an overlapping cell constituted by a CDMA wireless private exchange / keyphone system to which the present invention is applied. (1) indicates an area serviced by a base station of a mobile communication network, and a CDMA radio private switch / keyphone system using a CDMA frequency channel in which a specific part of the service area is not used by a neighboring mobile communication network base station as shown in (2). Consists of overlapping cells. In the area (1), home subscribers and external subscribers are provided with a communication service through a base station of a mobile communication network. When the home subscriber enters the area (2), the frequency channel switching procedure of FIG. 3 is followed to automatically switch to the CDMA frequency channel allocated to the overlapping cell without user intervention. After the home subscriber's terminal is switched to the CDMA frequency channel used by the CDMA wireless private exchange / keyphone system, CDMA cellular telephones and PCS telephones are used to provide incoming and outgoing services from landline and mobile telephone networks as well as internal and external signals. Get provided. On the other hand, when the external subscriber enters the area (2), it maintains access to the mobile communication network base station so that the CDMA wireless private exchange / keyphone system is not served.

A roaming control function block of a CDMA wireless private exchange / keyphone system for distinguishing a home subscriber from an external subscriber and performing a roaming control function is shown in FIG.

The base station forward link monitor unit 1 demodulates the pilot / synchronous / calling channel of the mobile communication network and extracts information of the corresponding channel. The PN offset and signal size information of the pilot channel signal received as a signal of a predetermined level or higher are transmitted to the system controller by searching for the pilot channel of the neighboring mobile communication network base station. It extracts the system time information and long code status information of the synchronization channel and transfers it to the system control unit to generate the system synchronization clock of the CDMA wireless private exchange / keyphone system. In addition, among incoming terminal outgoing messages transmitted through the calling channel, the CDMA enters the CDMA system and monitors whether the registered home subscriber is called.

The channel conversion command unit 2 is a CDMA frequency channel allocated to a CDMA radio private exchange / keyphone system formed as an overlapping cell in a mobile communication network base station when a home subscriber enters the area (1) from the area (1) of FIG. 1. The channel assignment message for channel change is transmitted to the corresponding terminal. For this purpose, the pilot channel search result of the base station forward link monitor is used. By transmitting a pilot signal received from a neighboring mobile communication network base station and a PN offset different from a neighboring base station pilot signal by a certain level, and transmitting a synchronization channel and a call channel according to the pilot channel signal and PN phase synchronization, Induce subscribers to idle handover to the CDMA wireless private exchange / keyphone system.

The access channel receiving unit 3 receives a home channel and an external subscriber who have entered the area (1) to (2) in FIG. 1 after performing idle handover to the CDMA wireless private exchange / keyphone system, and then receives the call channel message. When it is found that some of the parameters related to location registration among the system overhead information are changed, a location registration request message transmitted is received and transmitted to the system controller.

The channel bank section 4 is composed of a series of base station modulation / demodulation channels for processing an incoming and outgoing signal for a terminal of a home subscriber existing in a service area of a CDMA wireless private exchange / keyphone system.

The system controller 5 analyzes the pilot channel search results of the base station forward link monitor and selects the PN offset and signal level of the pilot signal having a PN offset different from the pilot signals received from the neighboring mobile communication network base stations. In the case of the home subscriber among the location registration messages received through the access channel receiving unit, a location registration response message of the terminal and a channel assignment message requesting the CDMA frequency channel change are generated and transmitted to the channel conversion command unit. In case of an external subscriber, only the location registration response message is generated and transmitted to the channel conversion command unit so that the corresponding terminal can maintain the connection to the mobile communication network base station. In addition, when the incoming call received through the call channel monitoring function of the base station forward link monitor includes a home subscriber registered by entering the CDMA wireless private exchange / keyphone system, the channel is converted into an internal call message of the CDMA wireless private exchange / keyphone system. Send to home subscriber through bank

3 shows a procedure for changing a CDMA frequency channel of a home subscriber roaming to a service area of a CDMA wireless private exchange / keyphone system. In this case, the mobile terminal receives the pilot channel signal 2 transmitted by the CDMA wireless private exchange / keyphone system by a predetermined level larger than the pilot channel signal 1 transmitted by the mobile communication network base station. Idle handoff (3) to the private exchange / keyphone system. The mobile terminal transmits a location registration request message 4 which is transmitted when it finds that some parameters related to location registration among the system overhead information received through the call channel message have changed. The system control unit receiving the location registration request message through the access channel receiving unit allocates a channel for requesting the CDMA frequency channel change of the location registration response message 6 and the call channel when the mobile terminal that transmits the message is the home subscriber 5. Send a message (7). On the other hand, when receiving a location registration request message from the external subscriber, the system control unit transmits only the location registration response message to the mobile terminal. When an incoming call 8 for a home subscriber entering the CDMA wireless private branch exchange / keyphone system is generated from the mobile communication network base station, it is converted into an internal call message (9) of the CDMA wireless private exchange / keyphone system and transmitted to the mobile terminal.

The channel switching command of the CDMA wireless private exchange / keyphone system has a call blocking effect by inducing idle handoff from the mobile communication network base station to the CDMA wireless private exchange / keyphone system for external subscribers, so it is restricted to operate only in a limited area such as an entrance to an office. do.

A CDMA wireless private exchange / keyphone system acting as a private base station is configured as an overlapping cell using a separate CDMA frequency channel in the service area of a mobile communication base station. In addition to the service, wired network access is provided. It also accepts incoming call service from mobile communication network without wired link between CDMA wireless private exchange / keyphone system and mobile communication network. The external subscriber is controlled from the overlapping cell by controlling access to the mobile communication base station without using the service of the CDMA wireless private exchange / keyphone system.

Claims (3)

In a CDMA wireless private exchange / keyphone system using CDMA cellular telephones and PCS telephones as terminals, by configuring an overlapping cell using a separate CDMA frequency channel in the service area of a mobile communication network base station, home subscribers are not only wired into the private network. A roaming control method for a subscriber, characterized in that an incoming call service is provided from a telephone network access service and a mobile communication network, and an external subscriber accesses a mobile communication network base station without using a service of a CDMA wireless private exchange / keyphone system. The method of claim 1, wherein the PN offset and signal size information of a pilot channel signal received as a signal of a predetermined level or more are acquired by searching for a pilot channel of a neighboring mobile communication network base station, and system time information and a long code state information of a synchronization channel are obtained. A base station forward link monitor means for acquiring and entering a CDMA wireless private exchange / keyphone system among the terminal outgoing messages transmitted through a calling channel and monitoring an incoming call of a registered home subscriber; A pilot signal received from a neighboring mobile communication network base station and a pilot signal having a different PN offset are transmitted at a predetermined level stronger than that of the neighboring base station pilot signal, and the synchronization channel message is transmitted in accordance with the pilot channel signal and the PN phase synchronization. Channel conversion command means for inducing an idle handover to a CDMA wireless private exchange / keyphone system by transmitting a call channel with a channel assignment message requesting a channel change to a CDMA frequency channel assigned to the private exchange / keyphone system; An access channel receiving means for receiving a location registration request message between a home subscriber and an external subscriber who has performed an idle handover to a CDMA wireless private exchange / keyphone system; Analyze the pilot channel search results of the base station forward link monitor to select the PN offset and signal size of the pilot signal that differs from the pilot signals received from the neighboring mobile communication network base stations and the PN offset, and register the location transmitted through the access channel receiving means. Among the messages, a home subscriber's location registration response message and a channel assignment message requesting a CDMA frequency channel change are generated, and an incoming call message including a home subscriber registered in the CDMA wireless private exchange / keyphone system is a CDMA wireless private exchange / keyphone. System control means for converting system internal call message The method according to claim 1, wherein the mobile terminal receives a pilot channel signal transmitted from the CDMA wireless private exchange / keyphone system at a predetermined level larger than the pilot channel signal transmitted from the mobile communication network base station so that the mobile terminal idles off the CDMA wireless private exchange / keyphone system. After receiving the location registration request message from the CDMA wireless private exchange / keyphone system when the mobile terminal detects that some parameters related to location registration among the system overhead information received through the call channel message have been changed. If a location registration request message is received from a home subscriber, a location registration response message and a channel assignment message requesting a CDMA frequency channel change of a calling channel are transmitted, while a location registration response message is received from an external subscriber. Send only to mobile terminal, Roaming for subscribers, when an incoming call to a home subscriber that enters a CDMA wireless private exchange / keyphone system from a network base station occurs, it is converted into an internal call message of the CDMA wireless private exchange / keyphone system and transmitted to the mobile terminal. Control method