KR20020028690A - Method for hand-off communication mobile CDMA is based ATM - Google Patents

Abstract

PURPOSE: A hand-off method for an ATM(Asynchronous Transfer Mode)-based CDMA(Code Division Multiple Access) mobile communication is provided to quickly perform a hand-off by setting an ATM virtual path in parallel in a source BSC(Base Station Controller) and a target BSC. CONSTITUTION: A source BSC transmits an ATM resource assignment request message to an NMP(Network Management Processor) for assigning and managing ATM resources necessary for setting a virtual path between the source BSC and a target BSC(S11). The source BSC requests a hand-off to the target BSCs(S12). One target BSC among the target BSCs for receiving the hand-off request from the source BSC requests ATM resources necessary for deciding the path with the source BSC to the NMP(S13). In case that the ATM resource assignment request message is received before an assignment request standby timer is ended, the NMP assigns ATM resources usable between the source BSC and one target BSC and transmits an ATM path setting completion message to the source BSC and one target BSC(S14). If the link setting with a channel of the target BSC is successfully performed and corresponding BTS information is received from the target BSC, a selector in the source BSC transmits an HDM(Handoff Direction Message) for instructing the hand-off performance between BSCs to an MS(Mobile Station)(S15).

Description

Method for hand-off communication mobile CDMA is based ATM

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the path establishment of CDMA mobile communication. In particular, since the ATM virtual path is set between control stations, an Asynchronous Transfer Mode (Asynchronous Transfer Mode) based ATM performs hand-off. It's about how to turn off.

In general, a CDMA mobile communication system is a communication between mobile stations that can communicate with anybody, anytime, anywhere, using radio waves in a space, or between a mobile station and a fixed station. A base station for managing resources, a control station for controlling the base station and sending and receiving messages to and from the base station, and an exchange station connected to the control station, another station, and another network to perform a switching role.

One of the most important and great features of the mobile communication system configured as described above is to ensure the mobility of the subscriber station. In order to ensure the mobility of the subscriber, hand-off technology is required.

The hand-off technique is a technique for switching the call path between the mobile station and the base station so that the call can be continuously maintained even if the mobile station leaves the service area of the base station or sector currently being provided with the service.

The hand-off scheme includes soft handoff, which is a handoff between adjacent base stations using the same frequency, and hard handoff, which is a handoff between a base station and an exchange using different frequencies.

As described above, the conventional CDMA mobile communication handoff is suitable for the service structure of voice univariate, and it is difficult to guarantee the mobility of the user at this time of switching to various data and video services.

Accordingly, an object of the present invention has been made in view of the above-mentioned problems of the prior art, and is based on ATM for performing a fast handoff by setting up an ATM virtual path in parallel between a source control station and a counterpart control station. It is to provide a CDMA mobile communication handoff method.

According to an aspect of the present invention for achieving the above object, the step of transmitting a message requesting the handoff from the mobile terminal to the source control station, the source control station analyzes the message to determine the base station And when the base station is a base station managed by the counterpart control station, the source control station simultaneously performing an ATM resource allocation request, a domestic ATM virtual path setting, and a handoff request to the counterpart control station by a network processor; Receiving a handoff request from the counterpart control station and simultaneously performing an ATM resource allocation request to the network processor and a local ATM virtual path setting in the counterpart control station; and receiving ATM resource allocation information of the source control station and the counterpart control station. Accordingly, the step of setting the ATM switch in the network processor.

Preferably, the local ATM virtual path setting in the source control station and the ATM virtual path setting in the counterpart control station are performed in parallel, a handoff is received at the control station, and a timer is driven when an ATM resource allocation request is made to the network processor. To be performed within a certain time.

Then, according to the ATM switch setting completion result from the network processor, the source control station performs link establishment between the counterpart control stations and instructs the mobile terminal to perform handoff.

1 is a diagram illustrating a system of ATM-based CDMA mobile communication according to the present invention.

2 is a flowchart illustrating a handoff method of ATM-based CDMA mobile communication according to the present invention.

* Description of the symbols for the main parts of the drawings *

10; Source control station

11: Call Control Processor (CCP) Modular

12: selector

13: vocoder

14: ATM (Asynchronous Transfer Mode) Switch

20: Network Management Processor (NMP)

30: counterpart control station

40: counter base station

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a diagram illustrating a system of ATM-based CDMA mobile communication according to the present invention.

Referring to FIG. 1, an ATM-based CDMA mobile communication system includes a source control station 10 that determines a hand-off of a mobile terminal and sets ATM resources of a virtual path and a virtual channel. A counterpart control station 30 for setting an ATM resource of the base station 40 added to the activation set to perform a handoff with the source control station 10, the counterpart control station 30 and the source control station ( 10) is configured as a network management processor (Network Management Processor) for allocating and switching the ATM resources for performing the handoff between.

The source control station 10 of the CDMA mobile communication system based on the present invention such as the Call Control Processor (CCP) modular 11 that supports call processing control and hand-off (Hand-off) and A selector 12 for establishing a link using ATM resources of the source control station, a vocoder 13 for compressing and transmitting voice information, the call control processor (CCP) 11, and a selector 12 And an ATM switch 14 for switching the vocoder 13.

The network management processor (NMP) includes an ATM switch 21 for switching the ATM virtual resource of the source control station 10 and the ATM virtual resource of the counterpart control station 30, and the counterpart control station 30. It consists of a call control processor (CCP) modular 22 for performing handoff and an ATM switch 21 for switching the counterpart control station.

In order to perform a hand-off function between the source control station 10 and the counterpart control station 30, the counterpart base station 40 newly added to an active set is added to the counterpart control station 30. In order to determine whether the information belongs to the < RTI ID = 0.0 >

When the source control station 10 requests the network management processor (NMP) 20 to set up an ATM route, the source control station 10 allocates an ATM resource to be used by a selector within the local station and the source control station. When (10) requests the counterpart control station 30 to handoff, the counterpart control station requests the network management processor (NMP) 20 to set an ATM route.

At this time, the source control station 10 and the counterpart control station 30 is connected to the network management processor (NMP) 20 and the ATM switch 14, the ATM switch 14 of the source control station 10 The ATM switch 21 of the NMP is connected to the virtual path (Vp) / virtual channel (Vc) value, and the ATM switch 21 of the counterpart control station 30 is also connected to the virtual path / virtual channel value. Is set.

For example, the VP / VC value of the ATM switch 14 of the source control station 10 connected to the ATM switch 20 of the NMP 20 is 4/5, and the Vp / Vc of the counterpart control station 30 is 4/5. If the value is 8/7, the ATM switch 20 of the NMP 20 switches different VP / VC values to perform a hand-off function to establish a path between control stations.

2 is a flowchart illustrating a handoff of ATM-based CDMA mobile communication according to the present invention.

Referring to FIG. 2, in the ATM-based CDMA mobile communication method, first, a pilot list currently managed by a mobile terminal is periodically monitored to determine a neighbor set or a non-neighboring station. If the pilot strength of the T_ADD or more, the mobile station transmits a Pilot Strength Measurement Message (PSMM) message to the source control station to perform a hand-off (Hand-off). (S10)

The source control station receiving the PSMM message from the mobile terminal analyzes pilot information included in the PSMM message and is a base station managed by a counterpart control station instead of a base station managed by the source control station. Determine hand-off.

The source control station that determines the handoff between the control stations as described above sends an ATM resource allocation request message to a network management processor (NMP) that allocates and manages the ATM resources required for the virtual path establishment between the source control station and the counterpart control station in the handoff between the control stations. send. (S11)

Then, the source control station performs ATM virtual path setting which the selector in the own station will use to determine the path from the selector in the own station with any counterpart control station.

When the network management processor (NMP) receives the ATM resource allocation request message for the first time from any control station, the network management processor (NMP) determines whether the control station which has transmitted the ATM resource allocation request is the source control station, and sets the allocation request waiting timer for a predetermined time. While driving.

Further, while the source control station transmits an ATM resource allocation request message to the network management processor NMP (S11), the source control station requests a hand-off to the counterpart control station. (S12)

One of the counterpart control stations which receives the hand-off request between the control stations from the source control station, provides the network management processor (NMP) with ATM resources necessary for determining the path with the source control station. Require. (S13)

At this time, one counterpart control station transmits an ATM resource allocation request message to a network management processor (NMP) before the timer driven for the predetermined time expires, and the network management processor (NMP) must receive an ATM resource allocation request message. do.

The one counterpart control station performs ATM virtual path establishment that the base station in the domestic station will use to determine the path between the base station to be added to the activation set and the source control station.

When the counterpart control station receives an ATM resource allocation request message from the network management processor NMP (S13), and receives the ATM resource allocation request message before the allocation request wait timer expires, the network management processor ( NMP allocates an ATM resource available between the source control station and one counterpart control station and transmits an ATM routing completion message between other stations to the source control station and one counterpart control station. (S14)

Meanwhile, when the timer expires, the network management processor (NMP) checks whether the source control station receives the ATM resource allocation request message, and if it is received, allocates the ATM resource based on the counterpart control stations received so far. Notify the control stations of the result. In addition, if not received, the counterpart control stations received so far are notified of the failure message.

As a result of the transmission of the ATM path setting completion message between the other stations of the network management processor NMP, the source control station receiving the same sets an ATM switch for communication between other stations by using the virtual path information of the allocated ATM resource.

The counterpart control station also sets up an ATM switch for communication between other stations using the virtual path information of the allocated ATM resource.

When the source control station is informed of the allocated base station information from the counterpart control station by the allocated ATM resource, the base station information is transmitted to the selector of the source control station.

When the selector in the source control station successfully performs link establishment with the channel of the counterpart control station and receives corresponding base station information from the counterpart control station, a handoff direction message (HDM) message instructs the mobile terminal to perform handoff between control stations. Send it. (S15)

After the mobile terminal successfully performs the handoff between the control stations, the mobile terminal transmits a HCM (Handoff Completion Message) message to terminate the handoff procedure.

As described above, the present invention separates the ATM virtual path setting of each control station and the ATM virtual path setting between other stations using a network management processor (NMP) to process ATM virtual path setting in parallel, thereby minimizing communication delay. This has the effect of supporting faster hand-off.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the examples, but should be defined by the claims.

Claims (4)

Sending a message to the source control station requesting to perform a handoff from the mobile terminal; The source control station analyzing the message to determine a corresponding base station; When the base station is a base station managed by a counterpart control station, the source control station simultaneously performing an ATM resource allocation request to a network processor, an internal ATM virtual path setting, and a handoff request to the counterpart control station; Receiving a handoff request from the counterpart control station and simultaneously performing an ATM resource allocation request to the network processor and establishing a local ATM virtual path in the counterpart control station; And setting an ATM switch in the network processor according to ATM resource allocation information of the source control station and the counterpart control station. 2. The ATM-based CDMA mobile communication handoff method according to claim 1, wherein the local ATM virtual path setting in the source control station and the ATM virtual path setting in the counterpart control station are performed in parallel. The handoff of the ATM-based CDMA mobile communication according to claim 1, wherein the counterpart control station receives a handoff and drives a timer to perform an ATM resource allocation request within the predetermined time period. Way. The method of claim 1, wherein the source control station further comprises the step of performing link establishment between the counterpart control stations and instructing the mobile terminal to perform handoff according to the completion of the ATM switch setup from the network processor. ATM-based CDMA mobile communication handoff method.