KR20030058685A - The method for changing to Uplink Synchronous Transmission Scheme in Wireless Telecommunication System - Google Patents

Abstract

PURPOSE: A conversion method to a USTS(Uplink Synchronous Transmission Scheme) in a wireless communication system is provided to maximize transmission capacity in a cell by maximizing characteristics of an orthogonal code. CONSTITUTION: A mobile station registers for a base station of a target cell in a normal mode(41). It is checked whether a network of the target cell supports a USTS mode(42). If the network supports the USTS mode, the mobile station is switched to a USTS mode(44). The network assigns a USTS channelization code and scrambling code to the mobile station(45). If the network does not support the USTS mode, it assigns a normal mode channelization code and scrambling code to the mobile station(43). If a wireless link is in the USTS mode and the network does not supports the USTS mode, changed from the USTS mode to the normal mode is performed before the handoff of the mobile station(41). In order to support he conversion to the normal mode, new scrambling code and channelization code are assigned to the mobile station(43).

Description

The method for changing to Uplink Synchronous Transmission Scheme in Wireless Telecommunication System

The present invention relates to an uplink synchronous transmission scheme (USTS) in a wireless communication system (hereinafter referred to as "USTS") mode conversion method and a computer-readable recording recording a program for realizing the method. The present invention relates to a medium, and more particularly, a method for converting to a USTS mode and a method of realizing when a mobile station (UE) registers in a network or registers in a network after completion of a handoff in a wireless communication system. The present invention relates to a computer-readable recording medium having recorded thereon a program.

In a conventional code division multiple access (CDMA) mobile communication network, a call generated between a mobile station (UE) and a base station (Node B) includes a forward channel and a reverse channel.

However, a plurality of forward channels between a plurality of mobile stations and a base station existing in one base station are synchronized with each other using time information, thereby inter-channel interference during demodulation using an orthogonal code having an orthogonality characteristic between each channel. Can be significantly reduced.

However, since the reverse channel from the mobile station to the base station does not use time information and cannot be synchronized, the orthogonal code of the orthogonality characteristic cannot be used, and thus the reverse interference increases as the channel of the mobile station increases. This ultimately limits the capacity in the reverse direction. Therefore, in order to increase the capacity in the reverse direction, all mobile stations synchronize in the reverse direction using the same time information between channels, thereby minimizing the interference between the channels by orthogonal codes using the orthogonality characteristics of each channel. have. This method is called "Uplink Synchronous Transmission Scheme".

That is, the USTS is a technology in which the base station controls the transmission time of the reverse data for the mobile stations in the cell managed by the base station so that the reverse signal of the mobile station using the orthogonal code can arrive simultaneously at the reference time desired by the base station. By doing so, it is possible to maximize the characteristics of the orthogonal code, thereby maximizing the transmission capacity in the cell.

In order for the mobile station to use the above-described USTS, first of all, the mobile station must first decide whether to use the USTS when registering the new network by initially registering or handing off the network.

In the present invention, if it is determined that the mobile station should use USTS in consideration of various factors of the mobile station, spreading factor / QoS / mobility, an algorithm for performing a USTS mode change is required.

The present invention has been proposed to meet the above-mentioned requirements. In the base station asynchronous wireless communication network, when a mobile station initially registers with a network or registers with a network after completion of a handoff, it uses a USTS (Uplink Syncronous Transmission Scheme) mode. Conversion of How and It is an object of the present invention to provide a computer-readable recording medium having recorded thereon a program for realizing the method.

1 is an exemplary configuration diagram of a wireless communication system to which the present invention is applied.

2 is a flowchart illustrating an embodiment of a channel allocation process for converting to a USTS mode when a handoff occurs according to the present invention.

3 is a flowchart illustrating an embodiment of a USTS mode conversion method according to the present invention;

* Explanation of symbols for the main parts of the drawings

10: mobile station (UE) 20: base station (Node B)

30: control station (RNC) 40: core network (Core Network)

In order to achieve the above object, the present invention provides a method for switching to an uplink synchronous transmission method in a wireless communication system, comprising: a first step in which a mobile station determines whether a network supports a USTS mode when a mobile station intends to use a USTS mode; ; A second step of registering as a USTS mode if the network supports the USTS mode as a result of the determination of the first step; And a third step of registering as a normal mode if the network does not support the USTS mode as a result of the determination of the first step.

The present invention also provides a method for switching to an uplink synchronous transmission method in a wireless communication system, comprising: a first step of receiving a normal mode registration from a mobile station when a handoff occurs; A second step of allocating a channelization code and a scrambling code in the USTS mode if the mobile network supports the USTS mode; And a third step of allocating a channelization code and a scrambling code in a normal mode if the mobile network does not support USTS mode switching of the mobile station.

On the other hand, the present invention provides a terminal system having a microprocessor for switching the USTS mode, comprising: a first function for determining whether the network supports the USTS mode when the mobile station intends to use the USTS mode; A second function of registering with the USTS mode if the network supports the USTS mode as a result of the determination of the first function; And a computer-readable recording medium having recorded thereon a program for realizing the third function of registering in the normal mode if the network does not support the USTS mode as a result of the determination of the first function.

The present invention also provides a network system having a large capacity processor, wherein the mobile network includes: a first function of receiving normal mode registration from a mobile station when a handoff occurs; A second function of allocating a channelization code and a scrambling code in the USTS mode if the mobile network supports the USTS mode; And a computer readable recording medium having recorded thereon a program for realizing a third function of allocating a channelization code and a scrambling code in a normal mode if the mobile network does not support switching the USTS mode of the mobile station.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exemplary configuration diagram of a wireless communication system to which the present invention is applied.

In the figure, "10" is a mobile station (terminal (UE), "20" is a base station (Node B), "30" is a control station (RNC: Radio Network Controller), and "31" is a drift control station (Drift RNC)). And " 32 " indicate a serving RNC, respectively.

As shown in FIG. 1, an asynchronous mobile communication system (UTRAN) includes a mobile station (terminal (UE)) 10, an asynchronous wireless network (base station (Node B) 20 and a control station (RNC) 30). It is organically connected. Here, the method for determining and converting to the USTS mode is a technique applied to the mobile station 10, and is a technique used when the mobile station 10 registers in the network or registers in the network after the handoff is completed.

The mobile station 10 is a wireless terminal including a mobile terminal, a personal digital assistant (PDA), and the like, which the user can carry and communicate with while moving. The mobile station 10 uses a forward channel when receiving data, and a reverse direction when calling. Use a reverse channel.

The voice, text and video messages transmitted and received by the mobile station 10 are connected to the control station 30 through the base station 20 for high frequency signal processing and call processing.

The base station 20 connects the mobile station 10 to the control station 30, performs wireless communication with the mobile station 10, and performs a wired / wireless conversion function of performing communication with the control station 30 by wire.

The control station 30 functions to connect a plurality of base stations 20 to coordinate the connection between the base stations 20.

2 is a flowchart illustrating a channel allocation process for converting to a USTS mode when a handoff occurs according to the present invention.

When the USTS transmits signals of a plurality of mobile stations 10 in one base station 20 in a reverse direction in accordance with a reference time managed by the base station 20, the USTS maintains orthogonality between channels, thereby maintaining each mobile station 10. It is to increase network efficiency by minimizing mutual interference.

In addition, USTS is a scheme for effectively using orthogonal codes for the reverse channel as in the forward channel. That is, in the same cell, all mobile stations 10 use the same scrambling code, and each mobile station 10 is distinguished by an orthogonalized channelization code.

The radio link is divided into modes by a scrambling code and a channelization code. The mode may be set to one of a normal mode, a non-USTS mode, and a USTS mode.

The normal mode has no timing control, and the mobile station 10 is distinguished only by the scrambling code.

In addition, the non-USTS mode has no timing control as in the normal mode, and the mobile station 10 is distinguished by the scrambling code and the channelization code while the mobile station 10 is distinguished by the scrambling code only.

The USTS mode has timing control differently from the non-USTS mode and the normal mode, and the mobile station 10 is distinguished by a scrambling code and a channelization code.

As shown in FIG. 2, when the mobile station 10 registers with the initial network, if the network supports the USTS, the mobile station 10 initially registers with the USTS mode. If the network does not support the USTS, the mobile station 10 first registers with the normal mode. Since the initial registration of the mobile station 10 in the network can be performed using an existing method, it is not discussed here.

When the mobile station 10 registers with the network when a handoff occurs (40), whether the mobile network supports the USTS mode or not. First, the mobile station 10 registers with the base station 20 of the target cell in the normal mode (41). Check whether the network to be moved in the target cell supports the USTS mode (42).

As a result of the check, if the mobile network supports the USTS mode, the mobile station 10 switches to the USTS mode (44). The mobile network allocates a USTS channelization code and a scrambling code to the mobile station 10 (45).

As a result, if the mobile network does not support the USTS mode, the mobile network allocates the normal mode channelization code and the scrambling code to the mobile station 10 (43).

For example, a mobile station 10 in a soft handoff area may establish two radio links, one in USTS mode and the other in Non-USTS mode. Herein, the other remaining non-USTS mode means that the mobile station 10 is configured with two or more radio links in the handoff area, so that other links than one USTS mode link establish a non-USTS mode link.

If the mobile station 10 is in the USTS mode, when the radio link is in the USTS mode, the change from the USTS mode to the normal mode is performed before the handoff if the network to be handed off and the mobile to support does not support the USTS mode. 41). A new scrambling code and a channelization code are then assigned to the mobile station 10 to support the transition to normal mode (43).

On the other hand, if the mobile station 10 is handed off and the base station 20 to be moved supports the USTS, mode switching from the Non-USTS mode to the USTS mode is performed after performing the handoff (44). At this time, for conversion to the USTS mode, the mobile network allocates a scrambling code and a channelization code to the mobile station 10 (45).

3 is a flowchart illustrating a method for converting a USTS mode according to an exemplary embodiment of the present invention, which corresponds to a case of switching from a normal mode to a USTS mode and a non-USTS mode to a USTS mode.

First, the serving control station 32 has a round trip time (RTT) measured by the base station 20 and a reference time T _ref of the base station 20 so that the mobile station 10 receives the base station 20. To calculate the initial synchronization time (T _{INIT_SYNC} ) to transmit the reverse signal.

Here, the reference time T _ref of the base station 20 is the maximum value of the one-way propagation delay in one cell, and all mobile stations 10 in the cell based on this value are the same at some point in time. It is determined whether or not to send a signal to the base station 20 in synchronization with each other. This value is a value set by the call setup control station 30 to the base station 20 and has the same value for each base station 20.

In addition, the initial synchronization time T _{INIT_SYNC} is a value calculated by which one mobile station 10 should transmit a signal based on the reference time T _ref of the base station 20. This value is different for each mobile station 10. This is because the distance that each mobile station 10 is far from the base station 20 is different.

After calculating the initial synchronization time T _{INIT_SYNC} , a Radio Link Reconfiguration Prepare message carrying a USTS indicator is drift controlled in the Radio Network Subsystem Application Part (RNSAP) of the serving control station 32. It transmits to the RNSAP of the station 31 (201). Through the USTS indicator, the drip control station 31 is requested from the serving control station 32 whether the USTS mode is supported.

Thereafter, the drift control station 31 receiving the radio link readjustment request message from the RNSAP of the serving control station 32 sends a radio link readjustment request message from the NBAP to the Node B Application Part (NBAP) of the base station 20 by using a USTS indicator, A transmission is sent with the USTS scrambling code and the USTS channelization code number (202).

Next, the base station 20 receiving the radio link reconfiguration request message, which is an NBAP message, from the NBAP of the drift control station 31, sends a Radio Link Reconfiguration Ready message in response to the drift control station 31 in the NBAP. Transmit to NBAP (203).

Subsequently, the drift control station 31 having received the radio link reconfiguration response message from the NBAP of the base station 20 receives the radio link reconfiguration response (Radio Reconfiguration Ready) message from the RNSAP to the RNSAP of the serving control station 32. The reference time T _ref , the USTS scrambling code, and the USTS channelization code number are transmitted and loaded (204).

Subsequently, the serving control station 32 receiving the radio link readjustment response message from the RNSAP of the drift control station 31 transmits a Radio Reconiguration Commit message from the RNSAP to the RNSAP of the drift control station 31. (205).

Next, the drift control station 31 receiving the radio link readjustment execution message from the RNSAP of the serving control station 32 transmits the radio link readjustment execution message to the NBAP of the base station 20 through the NBAP (206).

When the base station 20, the drift control station 31, and the serving control station 32 are ready to switch to the USTS mode by the above-described series of message exchanges, the radio resource control of the serving support node 32 is RRC (Radio Resource Control). In step 207, a physical channel reconfiguration message is transmitted to the RRC layer of the mobile station 10 (207).

When the physical channel readjustment request message is transmitted to the mobile station 10, a substantial physical channel change is performed between the mobile station 10 and the base station 20 (208).

Thus, the conversion procedure from the non-USTS mode and the normal mode to the USTS mode is completed by the mobile station 10 sending a physical channel reconfiguration complete message to the serving control station 32 through the RRC layer (209). ).

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. Will be evident to those who have knowledge of

The present invention as described above, the base station controls the transmission time of the reverse data for the mobile stations in the cell managed by the base station so that the reverse signal of the mobile station using the orthogonal code at the desired reference time can arrive at the same time, By maximizing the characteristics of the orthogonal code, there is an effect that can maximize the transmission capacity in the cell.

Claims (7)

A method of switching to an uplink synchronous transmission scheme in a wireless communication system, A first step of determining whether the network supports the USTS mode when the mobile station intends to use the USTS mode; A second step of registering as a USTS mode if the network supports the USTS mode as a result of the determination of the first step; And A third step of registering as a normal mode if the network does not support the USTS mode as a result of the determination of the first step Method of switching to an uplink synchronous transmission scheme in a wireless communication system comprising a. The method of claim 1, And the mobile station has one USTS mode and two or more Non-USTS modes in a handoff area. A method of switching to an uplink synchronous transmission scheme in a wireless communication system, The mobile network may include a first step of receiving normal mode registration from a mobile station when a handoff occurs; A second step of allocating a channelization code and a scrambling code in the USTS mode if the mobile network supports the USTS mode; And A third step of allocating a channelization code and a scrambling code in a normal mode if the mobile network does not support switching the USTS mode of the mobile station; Method of switching to an uplink synchronous transmission scheme in a wireless communication system comprising a. The method of claim 3, wherein The second step, A fourth step of calculating an initial synchronization time T _{INIT_SYNC} and transmitting a radio link reconditioning request message carrying a USTS indicator from a serving control station to a drift control station; A drift control station receiving the radio link readjustment request message from a serving control station, transmitting a radio link readjustment request message together with a USTS indicator, a USTS scrambling code, and a USTS channelization code number to a base station; A sixth step of receiving a radio link readjustment request message from the drift control station by transmitting a radio link readjustment response message to the drift control station in response thereto; A seventh step of receiving a radio link readjustment response message from the base station by transmitting a T _ref , a USTS scrambling code, and a USTS channelization code number to a serving control station; An eighth step of the serving control station receiving the radio link readjustment response message from the drift control station, transmitting a radio link readjustment execution message to the drift control station; A ninth step of receiving a radio readjustment execution message from a serving control station by a drift control station transmitting a radio readjustment execution message to a base station; A tenth step of transmitting a physical channel reconditioning request message from the serving support node to the mobile station when the base station, the drift control station, and the serving control station are ready to switch to the USTS mode when the above-described message exchange is performed; An eleventh step of performing a substantial physical channel change between the mobile station and the base station when the physical channel readjustment request message is transmitted to the mobile station; And Thus, the conversion procedure to USTS mode is a twelfth step that is completed when the mobile station sends a physical channel reconditioning completion message to the serving control station. Conversion method to an uplink synchronous transmission scheme in a wireless communication system comprising a. The method of claim 4, wherein The initial synchronization time (T _{INIT_SYNC} ), Using a base station reference time, which determines at which point all mobile stations in a cell, based on the maximum value of the one-way propagation delay in one cell, should be synchronized at the same time. A method for converting an uplink synchronous transmission method in a wireless communication system, characterized in that it calculates how much delay the mobile station should transmit a signal with. In order to switch the USTS mode, the terminal system having a microprocessor, A first function of determining if the network supports the USTS mode when the mobile station intends to use the USTS mode; A second function of registering with the USTS mode if the network supports the USTS mode as a result of the determination of the first function; And A third function of registering in the normal mode if the network does not support the USTS mode as a result of the determination of the first function A computer-readable recording medium having recorded thereon a program for realizing this. In a network system with a large processor, A first function for the mobile network to receive normal mode registration from the mobile station when a handoff occurs; A second function of allocating a channelization code and a scrambling code in the USTS mode if the mobile network supports the USTS mode; And A third function of allocating a channelization code and a scrambling code in a normal mode if the mobile network does not support USTS mode switching of the mobile station A computer-readable recording medium having recorded thereon a program for realizing this.