KR19990002838A - Multi-Channel Search Method for Call Forwarding and Receiving Service in CT-2 Base Station - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a CT-2 terminating system, in particular, continuity of service when the number of channels to be used for additional call, calling, location registration and tracking to be additionally serviced in a CT-2 system without a pilot channel is reduced. The present invention relates to a method of optimizing a service by a priority control method in order to secure the service.

In the conventional CT-2 system, there is a problem of using only one search channel or securing a separate radio frequency band, and since the priorities for incoming, location registration, and location tracking are not set, Service is difficult, and since the common line signaling cannot be used in the FDMA / TDD scheme, there is a disadvantage in that the entire function cannot be performed when there is only one available channel. In addition, in the operation method, there is a problem that the service is not easy to change because it does not download a separate configuration information for the user to the database.

The present invention can solve the limitation that the CT-2 system is used for call-only or call-only by applying priority even when only channels below a certain threshold remain in the CT-2 system having limited resources. Provides a multi-channel search method.

Description

Multi-Channel Search Method for Call Forwarding and Receiving Service in CT-2 Base Station

TECHNICAL FIELD The present invention relates to a CT-2 terminating system, in particular, continuity of service when the number of channels to be used for additional call, calling, location registration and tracking to be additionally serviced in a CT-2 system without a pilot channel is reduced. The present invention relates to a method of optimizing a service by a priority control method in order to secure the service.

Wireless personal communication can be said to have been developed by the desire to escape direct connection with the conventional wired communication network and the desire to give mobility to the terminal or the user. In such a wireless personal communication system, various methods are used according to a user's usage environment and service area.

Cordless telephones (commonly referred to as CT) are the oldest technologies in portable personal communications that fall into the category of low mobility, low power and two-way connectionless voice communications. CT was introduced in the late 1970s using analog wireless technology. Later, advanced second generation CT systems such as CT-2 and DECT with digital wireless technology were developed.

The MPT 1322 CT system, called CT-0 system, has a limited number of channels as well as a very high blocking probability, which leads to a need for a new CT system that can replace it. To meet this, the CT2 Common Air Interface (CAI) was developed using digital transmission and time division multiplexing. CT-2 first digitizes speech with an adaptive differential pulse code modulation (ADPCM) of 32 kbps and then uses Gaussian filtered Frequency Shift Keying (GFSK) with a control signal. It is modulated by a carrier at a rate of 72 kbps and transmitted using a frame of 2 ms.

Each frame is composed of two bursts, one base station-to-handset and one handset-to-basestation, and are transmitted. The above-described method is called a duplex method, and an expensive duplex filter required for frequency duplication is replaced with a switching element, the use of transmit / receive antenna diversity and the allocation of an arbitrary frequency band are possible. have.

The spectrum allocation of the CT-2 consists of 40 frequency division multiple access (FDMA) channels of 100 kHz in the 910-914 MHz band. The 100 kHz band results in a reduction in band efficiency compared to CT1, maximum transmit power is 10 mW, and two stages of power control can reduce the desensitization of the base station receiver and improve the frequency recycling characteristics. It has the advantage of being.

The CT-2 can also support data transmission up to 2.4 kbps using voice codecs, and can support high-speed transmission by connecting 32 kbps bearer channels directly. CT-2 was recommended as the standard for telepoint networks. In a telepoint network, wireless payphone service is provided through a cordless base station. Incoming call is not a basic service. This requires additional functions such as manual location registration and paging.

The CT-2 system is a digital telephone outgoing-only mobile phone developed by CT-1, which is used in homes. The subscriber who has a phone (terminal) makes a call using a wireless repeater installed in the city, road, and public places. It is a wireless communication service that can be called.

The CT-2 system is currently rapidly increasing in number due to several advantages.

One is ease of use. In other words, the phone is small and light, so it is easy to carry and use, and the lifespan of the power supply is three times longer than that of the existing cellular phone. In addition, if a home base station is installed, it can be used as a city phone when going out with a general wireless telephone at home.

Secondly, the phone price and usage fee are low. Simple functions make the phone cheaper and cheaper to use.

Third, the currency is clean without confusion. It is digital and has excellent call quality and is very safe in terms of communication security.

Fourth, it is more convenient to know and use the callable area. Although the base station antenna can move while moving within a radius of about 200M range, since the base station does not yet have a HAND OVER function, the call is terminated when the base station leaves. In addition, since the base station antenna is mainly installed on the main road and the radio wave power is weak (10mW), the call may not be made in the alleys, buildings, and the like.

1 shows a configuration diagram of a conventional CT-2 incoming system. The CT-2 terminating system generates a user's data and allocates a channel to a subscriber by using a handset and a wireless channel of each cell area for generating and transmitting data to a base station through a wireless channel. A base station which actually communicates with a subscriber (hereinafter referred to as a BS), a base station controller (hereinafter referred to as a BSC) that controls a plurality of base stations and a function of managing idle channel state information of the base station. It has a hierarchical structure composed of a base station management system (hereinafter referred to as BSMS).

However, outgoing dedicated CT-2 systems currently use one channel for searching to detect incoming or outgoing calls. In addition, the Canadian CT-2 + system uses a common signaling channel (CSC) method to provide separate radio frequency bands for location registration, location tracking, and handover functions. To secure.

In the conventional method, there is a problem of using one search channel or securing a separate radio frequency band, and since the priorities for call forwarding, location registration, and location tracking are not set, smooth service for a call is difficult. However, since the common line signaling method cannot be used without a separate frequency allocation, there is a disadvantage in that the whole function cannot be performed when there is only one available channel. In addition, in the operation method, there is a problem that the service is not easy to change because the separate configuration information for the user is not downloaded as a database.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the multi-channel scanning function and time division method for the base station apparatus in the CT-2 system of the FDMA / TDD method that does not use the common channel signal method ( When the number of available channels for incoming service, originating service, location registration and location tracking is reduced by using time sharing, a multi-channel search method can be used to maximize the call utilization of the base station by assigning priorities to the services. It aims to provide.

1 is a block diagram of a conventional CT-2 incoming system

2 is a hardware configuration diagram of a four-channel base station

3 is a flowchart illustrating a multiple search control method according to the present invention.

Detailed description of the symbols for the main parts of the drawings

101. Subscriber device 102. Base station device 103. Base station controller

104. Base station management apparatus 201. Radio channel card 202. Main processing unit

203. Wired connections

The present invention for achieving the above object consists of the transmission process of the operation database of the base station, the transmission process of the database for the multi-channel search of the base station, the idle channel priority definition process and the channel operation process.

When the base station is dedicated to outgoing, it may be used for wireless connection with a terminal attempting to make outgoing through only one channel. However, multi-channel search is required for sending or receiving messages in a separate channel for sending CIS messages for separate location registration or polling for location tracking. In addition, when handover occurs in a base station of a neighboring cell, if a command of channel switching for handover is received from a BSC, a separate channel is used as a search so that a wireless connection can be made through a multi-channel search during a reset period in a terminal. shall.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. 2 shows a configuration diagram of the base station apparatus hardware of the CT-2 destination system.

The CT-2 terminating system transmits configuration information on how much idle channel is left in the base station to the N BSCs connected to the lower part of the upper device called BSMS. Information will be sent. FIG. 2 is a diagram illustrating a hardware configuration of a base station. A radio frequency channel (hereinafter referred to as an RF channel) for connecting a CT-2 terminal and a radio interface CAI (Common Air Interface) card and the RF channel ( 201) A main processor 202 having a function of managing a card and an air interface CAI in association. The user information is transmitted through the wired connection processing unit 203 to communicate with the ISDN subscriber or the POTS subscriber.

Typically, the RF channel card of the base station is configured to accommodate up to eight channels depending on the communication capacity, but Erlang, a unit for measuring the reuse efficiency of the frequency or the traffic intensity in the cell area. Considering this, 4 to 6 channels are the most widely used.

Each RF channel card consists of a dedicated processor or general purpose processor that conforms to the CT-2 CAI specification to form a wireless interface suitable for digital transmission. Each RF channel card refers to an operation database of a base station and is controlled by a main processor to transmit a paging signal message for an incoming call, search for an idle channel for origination, a CIS for location registration and location tracking. In order to transmit a CPP Information and Status Codeword signal or to track a terminal on a list of personal identification codes (hereinafter referred to as PIDs) registered by a CIS at a base station, polling is scheduled according to a predetermined priority. Configure to service during intervals. Table 1 shows an example of the configuration of the database for channel control in the base station.

[Table 1] Configuration of database for channel control at base station

Field name Number of fields Record name Number Volume unit Operation table according to the number of remaining channels Number of RF channel cards (typically eight) Service priority Handover One byte Decimal Outgoing call One byte Decimal An incoming call One byte Decimal CIS One byte Decimal Polling One byte Decimal Repeat cycle Handover One word sec Outgoing call One word sec An incoming call One word sec CIS One word sec Polling One word sec Status management table Number of RF channel cards (typically eight) purpose of use One byte ASCII

The operation of the improved multiple search method for the originating / receiving service in the CT-2 base station according to the present invention will be described in more detail below with reference to FIG.

The operation process of the improved multi-search method for the originating / receiving service in the CT-2 base station according to the present invention is largely a process of creating a database, transmitting a base station operating database, and operating a database for multiple search of the base station. The process consists of an idle channel priority definition process and a channel operation process.

In the multiple search process, the system is initialized or various operation and configuration databases necessary for operation are transmitted from the BSMS to the BS through the BSC to designate the channel to be used by the base station for the multiple search of the base station. After the above process, the base station downloads the database of the corresponding hardware interface of the base station from the database part for channel control, and when the base station operates in the call processing mode, proceeds with the service by referring to the downloaded database. Enter the standby state.

When operating in the call processing mode in the above process, the base station searches for the number of idle channels except for the channel currently being used, and starts a search operation for the incoming call using the information.

According to the number of idle channels retrieved by the above process, except for the channel currently used by the subscriber, the utilization of the temporary channel is found in the database downloaded in the above process, and the verification process for the incoming call is performed according to this information. Table 2 shows examples of prioritization by function in multiple searches.

[Table 2] Example of Prioritization by Function in Multiple Searches

Anti-quadrant continuity Prioritize services based on remaining channel count Remaining channel 4 3 2 One Handover × One One One One An incoming call ○ 2 2 2 2 Outgoing call × 3 3 3 4* CIS polling × 4 4 4 3 *

If the CT-2 system is used exclusively for incoming calls, the database table assigns a high priority to the incoming call service, and when used for outgoing only, assigns a high priority to the outgoing call service.

After the above process, whenever a channel is occupied by the subscriber, the database for the corresponding interface is selected by referring to the priority information database for the remaining available channels.

If there are four or more idle channels, three military services can be supported simultaneously by referring to the four channel table of the database.

When the number of idle channels is three, the new service for the CT-2 system is an outgoing call service or an incoming call service, and the priority service is provided, and three groups can simultaneously support the service.

If the number of idle channels is 2 or less, three groups of services cannot be supported at the same time.If two idle channels exist, split service by priority control and time control of the service table is performed by time division method for two channels. Make sure you can apply.

When only one idle channel remains, three services cannot be supported at the same time, and only services designated in priority 1 or 2 of the service table are supported by the time division method. In this case, since the service also has only one channel and supports the service, the service is provided by partitioning by the time defined in the table. When the subscriber terminates the call within the quantity of the installed RF channel card, it shall refer to the database for the idle channel and operate according to the operation data when m channels remain.

According to the above configuration, the present invention can solve the conventional problem that the CT-2 system having limited resources is used only for outgoing calls or only for incoming calls even when only an idle channel remains below a predetermined reference value.

Claims (6)

A subscriber station for generating data of a user and transmitting the data to a base station through an air interface CAI; A BS for allocating a channel to a subscriber by using a wireless channel of each cell area and actually communicating with the subscriber through the assigned channel; BSC to control multiple base stations and In a CT-2 incoming system composed of a BSMS having a function of managing idle channel state information of the base station, Generating various operational data and configuration databases for the multi-channel search of the base station in the BSMS; Transmitting the operation database of the base station generated in the process from the BSMS to the base station via the BSC; Defining a usage of each channel by searching for a number of idle channels except for a channel currently used by a subscriber in the database; A process of operating a channel according to a use purpose by using the result of the process of defining an idle channel; The multi-channel search method for the incoming / outgoing service in the CT-2 base station, characterized in that comprises. The method of claim 1, wherein in the process of creating a database of the base station, Initiating a system at the CT-2 base station by creating a priority database table using call services such as incoming, location tracking, and location registration at the time of system initialization or BSMS for multi-channel retrieval. Multi-channel search method for incoming service. The method according to claim 2, If the CT-2 system is dedicated to an incoming call, assign a high priority to the incoming call service, When used exclusively for outgoing, multi-channel search method for outgoing / incoming service in CT-2 base station, characterized in that a priority table is created by allocating high priority to outgoing call service. The method of claim 1, wherein in the prioritization process of the idle channel, And selecting a corresponding table from a priority database table downloaded from the BSMS according to the number of idle channels. The method according to claim 4, If you have two idle channels, A multi-channel retrieval method for an outgoing / incoming service in a CT-2 base station, characterized in that the service of a two-channel service database table supports split service by priority and time control. The method according to claim 4, If the number of idle channels is 1, A method for multi-channel searching for an incoming / outgoing service in a CT-2 base station, characterized in that only priority 1 and priority 2 of the service priority database table are supported by a time division method.