KR100777512B1 - Method of hand-off by swapping - Google Patents

Abstract

The present invention relates to a handoff process in a control station of a mobile communication system. The handoff method using the swap method according to the present invention is active in another sector or another base station in the same base station according to a channel setting or release request of the mobile station. In soft or soft handoff of a mobile communication system according to each type of pilot present, it is characterized in that the addition and release of pilot channels are simultaneously processed in a swap scheme.

According to the present invention, the control station performs channel addition and channel release at the same time by using a swap method during soft handoff and softener handoff to prevent call release and to quickly cope with a rapidly changing wireless environment. The effect is expected.

Soft Handoff, Softer Handoff, Pilot Channel, Swap

Description

Handoff method using swap method {Method of hand-off by swapping}

1A to 1E are diagrams illustrating types of handoff in a mobile communication system.

Figure 2 is a flow chart illustrating the operation of each case of the handoff method using a swap method according to an embodiment of the present invention.

The present invention relates to the addition and deletion of a pilot channel during handoff processing of a base station controller (BSC) in a CDMA mobile communication system. The present invention relates to a handoff method using a swap method that prevents call release and copes quickly with changes in the wireless environment.

Hand off refers to changing a call path to a moved cell in order to continue to maintain a call when the UE moves out of the area of the serving base station to another base station. Unlike the analog method, which supports hard handoff, which is a method of disconnecting an existing line first and then connecting to a new base station, the soft hand, which is a function of maintaining a call path with two or more base stations simultaneously in the CDMA method. Soft hand off is also supported.

In the IS-95 method, when a terminal moves to a base station belonging to another switching center, when changing a communication channel to another frequency channel, and when changing to a communication channel having different frame offsets, it is called a hard handoff.

Soft handoff uses CDMA's rake receive function to support new call paths while maintaining the existing call paths when handoffs between base stations or sectors belonging to the same frequency, same frame offset, and same exchange. Thus, it accepts two channels. In particular, intersectoral soft handoff of the same base station is called softer handoff.

1A to 1E are diagrams illustrating types of handoffs of a mobile communication system.

1A to 1E, when a cell is a communication area of one base station, the cell is divided into three and one-third is one sector.

In the case of FIG. 1A, when the sectors of the base station 1 are referred to as sectors 11, 12, and 13, respectively, when the mobile station moves from sector 11 to sector 12 through sector 12, the mobile terminal is connected to an active pilot in sector 11. In addition, the sector 12 is in an active pilot state and transmits a PSMM (polit strength measurement message) for releasing the pilot channel of the sector 11 and adding the pilot of the sector 13 to the base station.

In this case, the PSMM is a strength information of the pilots measured by the mobile terminal to add a strong pilot signal from the control station receiving the PSMM through the base station to be used between the terminal and the base station, among the currently used pilot channels The weakening of the signal is to release it.

In addition, according to the channel addition and release instruction, the base station determines whether there is an active channel currently connected to the terminal to distinguish whether it is a soft handoff or a softer handoff.

Accordingly, in the case of FIG. 1A, since the pilot channel should be added and released while the base station 1 is connecting the active channel with the terminal, the softener is added and the softener is released.

Similarly, in the case of FIG. 1B, when the mobile terminal moves from sector 11 of base station 1 to sector 31 of base station 3 through sector 21 of base station 2, the first pilot channel is connected with sector 11 and moves sector 21 and pilot channel as it moves. After connecting, as shown in FIG. 3, when the mobile station moves to the sector 31 communication area of the base station 3, the pilot channel release with the sector 11 and the pilot channel addition with the sector 31 are simultaneously requested.

In this case, since the sector 21 to which the active channel is currently connected and the sector 11 to request pilot channel release are different base station areas, it is referred to as soft release. Likewise, the sector 21 to which the current active channel is connected and the sector 31 requesting addition of a pilot channel are similarly referred to as soft release. Since this is a different base station area, it is called soft addition.

1C corresponds to a case in which the mobile terminal moves from sector 11 of base station 1 to sector 21 of base station 2 via sector 12, and may be referred to as soft release and soft addition. In this case, when the active channel is currently connected to sector 22 of base station 2, a pilot channel release with sector 11 of base station 1 and a pilot addition request with sector 21 of base station 2 are performed. Corresponding.

Lastly, in FIG. 1E, the terminal connects the active channel to sector 12 of base station 1 and sector 22 of base station 2, and requests for channel release from sector 11 of base station 1 and channel addition with sector 21 of base station 2. In this case, when the base station is different from the softener to add and release the softener.

When the soft or softener addition / release request is made for each of the five types as described above, in the case of FIGS. 1A and 1B, the control station adds and releases the pilot channel at the same time. This method is called a swap method, and a method of adding and releasing pilot channels at the same time.

In addition, in the case of FIGS. 1C to 1E, only pilot channel release is preferentially processed without adding and removing pilot channels at the same time by using a swap method.

That is, in the case of FIG. 1C, only softer release of the pilot channel is performed in soft addition and soft release, and in FIG. 1D, only soft release of pilot channel is performed in soft addition and soft release. In releasing softener and releasing only the softer release of the pilot channel.

1C to 1E, the UE needs to request the pilot channel addition by transmitting the PSMM to the BS once again.                         

As described above, in the case of a softer addition / softener release (FIG. 1A) that requires the addition and release of pilot channels in a sector within the same base station, or a software for requesting addition and release of pilot channels between different base stations. In the case of addition / soft release (FIG. 1b), the swap method of simultaneously adding and releasing channels is used, and in other cases, only channel release is performed first, and channel addition is performed only when the terminal additionally requests channel addition again. In addition, in the handoff process, the addition of the pilot channel is not performed properly, thereby increasing the probability of the call being released, and there is a problem in that it cannot cope with a constantly changing wireless environment.

In order to solve the above problems, the present invention, when performing the handoff in the control station of the mobile communication system to perform the channel addition and release at the same time in any case of soft handoff and softer handoff so that the call is not released Therefore, the object of the present invention is to provide a handoff method using a swap method that can cope with a wireless environment quickly.

The handoff method using a swap method according to the present invention,

In soft or soft handoff of a mobile communication system according to each type of active pilot in different sectors or other base stations in the same base station according to a channel setting or release request of the mobile station,
The mobile station finds all the pilot signals that can be found at the current location, and transmits the strength information of the signal to a control station through a base station by putting the strength information of the signal in a PSMM (Pilot Strength Measurement Message), Identifying which base station the active channel is connected to, and as a result of the checking, the soft add-softener release and soft-softer soft-soft according to each type of the active channel present in another sector or another base station in the same base station. And adding and releasing the pilot channel by simultaneously processing a request for at least one of the release and the softener addition-softener release.

Preferably, the adding and releasing of the pilot channel may include: adding a softener when there is an active pilot in another sector in the same base station requiring channel addition and an active pilot in another base station requiring channel release. Processing a soft release request in the presence of the same by a swap method, and performing addition and release of a pilot channel.

Preferably, the adding and releasing of the pilot channel may include a soft addition request when an active pilot exists in another base station requiring the channel addition and an active pilot in another sector in the same base station requiring the channel release. And simultaneously adding and releasing the pilot channel by simultaneously processing the existing soft release request.

Preferably, the adding and releasing of the pilot channel may include: a softer adding request in which an active pilot exists in another sector in the same base station requiring the channel addition, and a base station different from the softener adding requesting base station. And adding and releasing a pilot channel by simultaneously swapping a soft releasing request in which an active pilot exists in another sector in the same base station requiring channel releasing.

Referring to the accompanying drawings, a handoff method using a swap method according to the present invention configured as described above is as follows.

In the case of the soft handoff and the softer handoff according to the exemplary embodiment of the present invention, as in the related art, a case similar to those of FIGS. 1A to 1E may be considered.

2 is a flowchart illustrating an operation in each case of a handoff method using a swap method according to an exemplary embodiment of the present invention.

The mobile station finds all the pilot signals found at the current location for handoff and transmits the signal strength information to the base station (S101).

The PSMM is sent to the control station to instruct the control station to add a pilot channel above a certain value and to drop a pilot channel below a certain value. In addition, the control station checks which base station the active channel connected to the mobile terminal is connected to, so as to add or remove a channel in the same base station to the softer handoff, and to add or release a channel in another base station Instructed by soft handoff (S102).

The mobile station receiving the channel addition and release command of the control station performs soft or softer addition / release (S103).

At this time, when the control station receives the channel addition and release requests simultaneously, in the case of FIGS. 1A and 1B, the control station performs channel addition and release using the soft swap method and the soft swap method (S104, S105). ).

In the operation shown in FIG. 1C, the soft addition request and the softener release request are performed in the present invention, and the control station performs soft-soft addition and release of pilot channels simultaneously according to the two request messages. A swap swap method is used (S106). That is, the pilot channel with the sector 21 of the base station 2 is added, and the pilot channel connected with the sector 11 of the base station 1 is released.

In addition, in the case of FIG. 1D, in the case of a softer addition request and a soft release request, the control station performs simultaneous addition and release of the pilot channel using the softer-soft swap method according to the two request messages (S107). To add a pilot channel with sector 21 of base station 2 and release the pilot channel with sector 11 of base station 1.

Lastly, in FIG. 1E, a softener addition request and a softener release request are transmitted from different base stations to the control station, respectively, using a softener-softer swap method (S108). A message and a release request message are performed to add a pilot channel with sector 21 of base station 2 and to release a pilot channel with sector 11 of base station 1.

At this time, the above five types of swap method is the operation to perform the addition and release of the channel at the same time means the same method, and assigned a meaning corresponding to each case, soft swap, soft swap, soft-soft swap, soft This is defined as soft-swap and soft-swap.

As described above, according to the present invention, the pilot channel is always connected in a direction in which the mobile terminal moves by using a swap method to simultaneously perform a softer and a soft handoff request according to a pilot addition and release request. By releasing the pilot channel from a small place, the call is not released by proper handoff, and the wireless environment changes due to the movement of the terminal can be coped with quickly.

 As described above, the handoff method using the swap method according to the present invention, in the handoff of the mobile communication system, in particular during the soft handoff and softer handoff does not add and release pilot channels at the same time. The method that handled only the pilot channel release first, instead of the call release method, prevented the release of the call and responded to the rapidly changing wireless environment by using the swap method simultaneously. There is.

Claims (4)

In soft or soft handoff of a mobile communication system according to each type of active pilot in different sectors or other base stations in the same base station according to a channel setting or release request of the mobile station, Finding all pilot signals found at the current location by the mobile station and transmitting the strength information of the signal to a pilot strength measurement message (PSMM) to a control station through a base station; Determining, by the control station, which base station the active channel to which the mobile station is connected is connected; According to the check result, the request for at least one of soft add-softener release, softener add-soft release, softener add-softener release according to each type in which the active channel exists in another sector or another base station in the same base station. And adding and releasing a pilot channel by simultaneously processing a swap method. The method of claim 1, The adding and releasing the pilot channel may include: Swap method for soft add request when active pilot exists in different sectors in the same base station requiring channel addition and soft release request when active pilot exists in other base stations in pilot requiring channel release And performing the addition and release of the pilot channel. The method of claim 1, The adding and releasing the pilot channel may include: The soft addition request when the active pilot exists in another base station of the pilot requesting channel addition and the soft release request in which the active pilot exists in another sector within the same base station requesting channel release are simultaneously processed by a swap method. A method for handoff using a swap method comprising the step of adding and releasing pilot channels. The method of claim 1, The adding and releasing the pilot channel may include: Soft pilot addition request in which an active pilot exists in another sector in the same base station requiring the channel addition, and active pilot exists in another sector in the same base station requiring channel release from a base station different from the softener addition request base station. A method of handoff using a swap method comprising the step of simultaneously processing a soft release request to perform the addition and release of a pilot channel.

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