KR19990081101A - Channel change / allocation method for simultaneous voice / data service of wireless subscriber line system - Google Patents

Abstract

The present invention relates to a method for simultaneously supporting a data service and a telephone service in a wireless local loop (WLL) system. The present invention provides a new radio resource allocation because the capacity of one base station is exceeded. If rejected, newly defined in the WLL standard by implementing a message about a radio resource change request that includes information for allocating the remaining band secured by reducing / changing a band of a channel already used by the base station itself to a new service. The present invention relates to a channel change / assignment method for voice / data simultaneous service of a wireless subscriber line (WLL) system that can be adapted to a user's multiple service requirements.

Description

Channel change / allocation method for simultaneous voice / data service of wireless subscriber line system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Wireless Local Loop (WLL) system using Code Division Multiple Access (CDMA) schemes. In particular, all radio resources for multiple services are in use. When the existing channel mode to support a new service at the same time.

In general, the WLL system has a wireless communication between the base station and the terminal station, except that the terminal station is fixed and there is no hand off function caused by the movement of the terminal station. It is the same as the principle. In addition, various services can be provided to a terminal station by connecting a terminal for voice service, a terminal for fax service, and a terminal for data dedicated service.

1 is a block diagram of such a general WLL system.

As shown therein, a voice service terminal 10 for a voice service, a modem 11, a fax terminal 12 for a fax service, and a data terminal 13 for a data-only service are connected by wire. And a terminal station 20 which connects the terminal having the WLL service request to the base station 30 by wireless communication, receives the airwaves propagated from the base station 30, and transmits the received air wave to each corresponding subscriber; Receives voice, data, control signals, etc., transmitted from the terminal station 20 through wireless communication, and transmits the voice, data, control signal, etc., transmitted from the base station controller 40 by wire to the base station controller 40. A base station 30 for receiving a control signal and transmitting the same to the terminal station 20 through wireless communication; A base station controller (40) located between the base station (30) and the switching center (50) to control a wired or wireless link during incoming / outgoing call processing and to manage the base station (30); It is composed of an exchange station 50 that controls the overall operation so that the WLL service can be made, and matches with the public switched telephone network (60).

As shown in FIG. 2, the terminal station 20 includes a wired telephone interface unit 21, which provides an interface for connecting the voice service terminal 10 and the modem 11, and an integrated service digital network. The ISDN interface unit 22 provides an interface for accessing the ISDN service terminal 12 so that the service can be provided, and an interface for accessing the data-only service terminal 13. The signals received from the serial input / output unit 23, the wired telephone interface unit 21, the ISDN interface unit 22, and the serial input / output unit 23, respectively, and received from the base station 30. Is modulated to transmit the signal received from the time switch unit 24 to the base station 30, and the signal received from the base station 30 is demultiplexed to the subscriber. And a W-CDMA modem unit 25 which demodulates and transmits the call to the time switch unit 24.

The wired telephone interface unit 21 detects a hook off of the line interface unit 21a for transmitting and receiving an analog signal to and from the voice service terminal 10 and 11 and the voice service terminal 10. The power supply unit 21b for providing a DC loop current to the line interface unit 21a and an analog signal received from the line interface unit 21a by adaptively predicting and encoding the time switch. An adaptive prediction encoding codec 21c which transmits to the unit 24, converts the adaptive predictive encoded signal received from the time switch unit 24 into an analog signal, and transmits it to the line interface unit 21a, and the voice. When the call of the service terminal 10 is detected, the ring / tone generator 21d generates and transmits a ring tone.

The ISDN interface unit 22 generates a signal transmitted from the line interface unit 22a for transmitting and receiving signals to and from the terminal for ISDN service, and the line interface unit 22a as a frame to the time switch unit 24. And a frame processor 22b for converting the frame received from the time switch unit 24 into a signal that can be recognized by the ISDN service terminal and transmitting the signal to the line interface unit 22a.

3 is a structural diagram of a radio access protocol commonly applied to a base station and a terminal station of a general WLL system as described above.

As shown therein, a radio resource control signal plane 200 for managing radio resources; A communication control signal plane (100) for controlling multiple communication connections and for controlling calls; Exchange signal information between the radio resource control signal plane 200 and the communication control signal plane 100, sense the type, state, and operation of a terminal device connected to a terminal station, and state of each functional entity. It consists of an application part (AP) 600 that manages the management.

The signal plane 200 and the communication control signal plane 100 include: a physical layer (L1) 300 for modulating and demodulating data and encoding and decoding a channel; A data link layer (L2) 400 for controlling errors in the transmitted data to reliably transmit the data, controlling the order of the transmitted data, and retransmitting the lost data; It is composed of a network layer (L3) 500 for controlling radio channel resources to be allocated, controlling synchronization information and system information for changing multiple service modes, and managing radio resources.

In addition, each signal plane 100 and 200 has a hierarchical structure according to an Open System Interconnection (OSI) reference model.

The network layer 500 of the communication control signal plane 100 includes an O & M entity (Operation & Maintenance: operation maintenance unit 510) that performs operation maintenance of a network, and a CC entity that performs multiple service connection control. Control: the access control unit 520), MM entity (Moblity Management: mobile management unit, 530) for performing registration registration / authentication / encryption, and the like.

In addition, the network layer 500 ′ of the radio resource control signal plane 200 may configure, maintain, and release radio resources between a terminal station and a base station, and support an RM entity (Radio Resource Management: Radio) for supporting a radio resource change procedure. A resource manager 540.

Here, the radio resource means a radio channel established between the terminal station and the base station, and generally refers to a signal channel (SGCH) and a traffic channel (TFCH).

In the general WLL system, a radio resource allocation process for radio access between the terminal station 20 and the base station 30 will be described.

First, the general WLL terminal station 20 supports general landline telephone service, ISDN service, and data-only service, but does not support all three of these services at the same time. Only support services.

Accordingly, if there is a service request from the data-only terminal 13, the entity 600 of the terminal station 20 transmits a channel allocation request message to the RM entity 540 of the network layer 500 ′. The RM entity 540 sends the received channel assignment request message to the base station 30. When the RM entity of the base station 30 receives the channel allocation request message from the terminal station 20, the RM entity transmits a channel allocation request response message to attempt random access to the base station 30 of the terminal station 20. Stop it.

After the base station 30 allocates the radio resource requested by the terminal station 20, the base station 30 transmits a channel assignment message including information such as service type, allocated frequency, and channel allocation history as information on radio resource allocation. To send).

The RM entity 540 of the terminal station 20 receiving the channel assignment message from the base station 30 instructs the physical layer 300 of the terminal station 20 to activate a corresponding radio resource (channel). When receiving the response from the 300, it notifies the AP entity 600 that the radio resource is set. This terminates the radio resource allocation procedure for the required data-only service.

In this operation, when all channels are allocated for the requested WLL service and there are no more assignable channels left in the base station 30, the terminal station 20 provides the voice service when the voice service is requested. Perform a general radio resource allocation procedure. That is, an access is attempted based on the initial transmission serial value, and when there is no response from the base station 30, an access is again attempted based on the specific transmission power value. After that, if there is no response from the base station 30, a random access is attempted based on the maximum transmission power value. At this time, since the base station 30 no longer has an assignable channel, the base station 30 cannot allocate a channel for a newly requested voice service, and thus transmits a rejection message of the radio resource allocation to the terminal station 20. As a result, the terminal station 20 does not provide the newly requested voice service and refuses.

As described above, the general WLL system has a disadvantage in that the requested service cannot be provided when a service is required in the absence of an extra channel that can be allocated.

In addition, when there is no channel assignable to the base station, when a new service is requested, other existing service is stopped and the channel allocated to the suspended service is allocated for the newly requested service, thereby limiting the assignable channel. When a service is required in the system, there was a limitation that only one service should be performed selectively.

The channel mode change receives the modem tone or the beep of the fax transmitted from the terminal station, recognizes it as a request for channel change, and initiates the channel change. There was a problem that the service is not suitable for supporting.

Therefore, the present invention has been proposed to solve the above-mentioned conventional problems, and an object of the present invention is to provide a newly requested service when a new service is required when all the radio resources for the service are in use. The present invention provides a channel change / allocation method for voice / data simultaneous service of a wireless subscriber line (WLL) system that changes a radio resource allocated to an existing service and allocates the newly requested service.

In order to achieve the above object, a channel change / assignment method for simultaneous voice / data service of a WLL system according to the present invention,

If the channel assignment is denied from the base station for the newly requested voice service due to lack of assignable channels, the terminal station transmits a channel change request message to the base station so that the channel already allocated for the data service is changed. Wow; Receiving the channel change request message, the base station changes the bandwidth of the already allocated radio resource according to the requested service type included in the channel change request message, and includes the changed new service type information in the change request message to send the change request message. A base station channel changing step of transmitting to a terminal station; The terminal station receiving the change request message activates a radio resource according to a new service type included in the change request message to change the radio resource of the data service, and transmits the change complete message to the base station. ; After allocating the radio resource allocated to the data service by reducing the radio resource allocated to the data service after the change completion message, the terminal station transmits a channel assignment request message to the base station to allocate a channel allocated to the voice service. A request step; The base station receiving the channel allocation request message is a base station channel allocation step of transmitting a channel allocation message to the terminal station in response to the channel allocation request, allocating radio resources according to the service type included in the channel allocation request message. It is characterized by the methodological configuration.

1 is a block diagram of a typical WLL system;

2 is a block diagram of a terminal station of FIG. 1;

3 is a structural diagram of a radio protocol of a general WLL system;

4 is a flowchart illustrating a method of changing a channel for simultaneous voice / data service of a WLL system according to the present invention;

5 is a flowchart illustrating a channel allocation method for simultaneous voice / data service in a WLL system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: voice terminal 11: modem

12: terminal for fax 13: terminal for data

20: Terminal station 30: Base station

40: base station controller 50: switching center

60: PSTN network

In the present invention, it is assumed that a wideband code division multiple access (W-CDMA) modem unit (MODEM) 25 of a general terminal station is operating properly for multiple transmission channel allocation. Dynamically change / allocate the band of the channel.

When a data service is required in the WLL system, an assignable channel is allocated for the data service to provide the data service. Therefore, when the WLL service is required, the required WLL service is performed to allocate all the channels of the base station 30, and when there is no more empty channel, when a new voice service is required, the voice / As a channel change / allocation method for simultaneous data service, a newly required voice service can be provided.

5 and 6 are flowcharts illustrating a channel change / assignment method for simultaneous voice / data service of a WLL system according to the present invention.

As shown here, if the channel allocation is rejected from the base station for the newly requested voice service due to lack of assignable channels, the terminal station reduces the channel already allocated for the data service and replaces the remaining channel for the data service with the voice service. A terminal station channel change request step (ST1) for defining and transmitting a channel change request message to the base station so as to allocate the channel change request message; The base station receiving the channel change request message changes the band of radio resources already allocated for the data service according to the requested service type of the terminal station included in the channel change request message, and includes the changed new service type information. A base station channel changing step (ST2) for transmitting a request message to a terminal station; Upon receiving the change request message, the terminal station changes the radio resource of the data service by activating a radio resource according to the new service type included in the change request message, and transmits the change complete message to the base station. ST3); When the radio resource for data service is reduced and secured according to the change request message, the terminal station channel allocation request step of transmitting a channel assignment request message to the base station to allocate the reserved radio resource for the newly requested voice service (ST4). )Wow; When the channel allocation request message is received from the terminal station, the base station transmits a response message for the channel allocation request to the terminal station and allocates a radio resource according to the service type included in the channel allocation request message to transmit the channel allocation message to the terminal station. A base station channel assignment step (ST5-ST6) is transmitted.

The channel change / allocation method for the simultaneous voice / data service of the WLL system according to the present invention configured as described above is as follows.

First, when a data service request is detected at the serial input / output unit 23 of the terminal station 20, a general radio resource allocation procedure is performed to allocate a radio resource from the base station 30 to provide a 128 kbps data service. At this time, the base station 30 allocates the allocated channel for the required WLL service so that the base station 30 no longer has an assignable channel.

In the state where there are no more empty channels, when a hook off for voice service is detected at the wired telephone interface unit 21 of the terminal station 20, a general radio resource allocation is provided to provide the voice service. Perform the procedure.

That is, an access is attempted based on the initial power output value, and if there is no response from the base station 30, the access is attempted again based on the specific power output value. If there is no response from the base station 30 thereafter, the terminal station 20 attempts to access based on the maximum transmission power value.

However, since all radio resources have already been allocated despite three access attempts of the terminal station 20, a CHANNEL ASSIGNMENT REJECT of the radio resource allocation for the telephone service is transmitted from the base station 30.

Then, if the AP entity 600 of the terminal station 20 can provide the data service and the voice service at the same time by changing the radio resource allocated for the data service, the AP entity 600 changes the attribute of the radio resource being used for the data service to the new service. In order to change the form, the terminal station 20 defines a message (RIU MODIFY REQUEST) requesting the channel change to the base station 30 and requests the RM entity 540. The RM entity 540 transmits the received channel change request message to the base station 30 through the data link layer 400 'and the physical layer 300 in sequence (ST1).

The structure of the channel change request message is shown in [Table 1].

IEI Information element Presence Format Length Message Type (0011) M V One IWUI or TWUI M LV 4-10 20 Service type M V 2 15 Channel Description M V 5 ~ 21

8 7 6 5 4 3 2 1 Information element delimiter (00100000 = SERVICE TYPE) Reserved RATE (011 = 64 kbps) CALL TYPE (0100 = Leased Line)

In [Table 1], the information field actually transmitted as the channel change request message includes a message type indicating the type of the message, a WLL user identification number (IWUI or TWUI) for identifying the terminal station, and a type of service. Service type and channel description. In each field, the message type is 1 byte, the WLL user identification number is 4 to 10 bytes, the service type is 2 bytes, and the channel type is 5 to 21 bytes in length.

The message in [Table 1] is a message for requesting a channel change, with the information in the message type field being "11", and this channel change request message is a service type as "100000" as shown in [Table 2]. In addition, the data service provided at the transmission rate of 128 kbps is changed to the transmission rate of 64 kbps (RATE; " 11 ") and the radio resource for the remaining 64 kbps is allocated (“100”). You will be asked.

The base station 30, which has received the channel change request message from the terminal station 20 in this manner, 64kbps data service that has already been provided at a transmission rate of 128kbps according to the service type of the terminal station 20 included in the channel change request message. Changes and allocates radio resources so that they are provided at a lower transmission speed. Then, the changed new service type information is included in the radio resource change message, and a radio resource change message (MODIFY REQUEST) is transmitted to the terminal station 20 to start a radio resource change procedure (ST2).

When the terminal station 20 receives the radio resource change request through the radio resource change message received from the base station 30, the terminal station 20 performs a radio resource change procedure in the terminal station 20, which is according to the single mode and the multi-mode. can be different.

Referring to the radio resource change procedure in the terminal station 20, the RM entity 540 of the terminal station 20, according to the new service included in the received radio resource change message, the corresponding radio resources to the physical layer 300. Instructs to change the attribute of the radio resource. It also deactivates the radio resources (signal channel, transmission channel) in use before receiving the radio resource change procedure from the base station 30. As a result, when the change of the new radio resource is successfully performed, a change complete message (MODIFY COMPLETE) is transmitted to the base station 30. However, if a problem occurs during the radio resource change procedure of the terminal station 20 and the radio resource change fails, the terminal station 20 transmits a change rejection message (MODIFY REJECT) to the base station 30.

When the change completion message (MODIFY COMPLETE) is received from the terminal station 20 that the radio resource has been successfully changed, the base station 30 notifies the AP entity of the base station 30 that the radio resource mode has been changed, and is providing the data service at 128 kbps. Is changed to 64 kbps at the request of the terminal station 20 to be provided (ST3).

When the radio resource used for data transmission is changed at the request of the terminal station 20, and an allocable transmission bandwidth of 64 kbps is secured, the terminal station 20 sends a channel allocation request message (i.e., to provide the requested voice service). CHANNEL REQUEST) is transmitted to the base station 30 to perform a radio resource allocation procedure (ST4).

The structure of the channel allocation request message (CHANNEL REQUEST) is shown in [Table 3].

8 7 6 5 4 3 2 1 Information element delimiter (00100000 = SERVICE TYPE) Reserved RATE (010 = 32 kbps) CALL TYPE (0010 = POTS)

As shown in [Table 3], the channel assignment request message of the terminal station 20 includes a message type field (Message Type) indicating a message type, and a WLL user identification number field (IWUI or TWUI or IWEI) for identifying the terminal station. ), Call Mode, Call Type, Service Type, and Slot Slot Selected Slot to select the time slot when paging do. The message type field has 1 byte, the WLL user identification number field has 4 to 10 bytes, the call originating field has 2 bytes, the service type field has 2 bytes, and the slot index selection field has a length of 2 bytes.

As shown in [Table 4], the channel allocation request message of [Table 3] has a service type of “100000”, and can be provided with voice service (PO10) at a transmission rate of 32 kbps (010; 32 kbps). The base station 30 requests allocation of radio resources.

The base station 30, which has received such a channel allocation request message (CHANNEL REQUEST) from the terminal station 20, transmits a response message (CHANNEL REQUEST ACK) for the channel allocation request back to the terminal station 20, and receives the received channel. The radio resource is allocated to the terminal station 20 by allocating a radio resource according to the service type included in the assignment request message. If a failure occurs in the radio resource allocation process at the base station 30 and the radio resource cannot be allocated, the base station 30 transmits a channel assignment rejection message (CHANNEL ASSIGNMENT REJECT) to the terminal station 20 (ST5-ST6). ).

In this way, in the case where the channel assignable to the base station 30 is limited, if the voice service is required, the terminal station 20 requests the base station 30 to reduce and change the radio resource allocated to the data service already being provided. When the radio resources allocated to the data service are reduced and changed to secure the spare radio resources that can be allocated, the channel allocation is requested to the base station 30 so that the voice service is provided to the radio resources. In this case, the required service can be performed simultaneously without being rejected.

According to the present invention, in addition to simultaneously supporting data and voice services of the WLL system, when a new service is required in a situation where available radio resources are limited, the present invention provides a service and a new service by changing a radio resource allocated to a service already being provided. Allocate to to allow multiple services at the same time.

As described above, the channel change / assignment method for the simultaneous voice / data service of the WLL system according to the present invention provides a newly requested service when a new service is required when all the radio resources for the service are in use. In order to reduce the radio resource allocated to the data service already provided at 128kbps, the channel change request message can be defined and transmitted to the base station to secure the extra radio resources that can be allocated due to the reduction of the radio resource allocated to the data service. It has an effect.

In addition, by allocating a channel allocation request message from the terminal station to the base station in order to allocate the radio resources obtained due to the channel change request to the newly requested service, the new requested service is not rejected even when the available radio resources are limited. Since the radio resources are dynamically changed and allocated to the newly requested service, the newly requested service can be provided at the same time.

Claims (4)

WLL service method, If the channel assignment is denied from the base station for the newly requested voice service due to lack of assignable channels, the terminal station transmits a channel change request message to the base station so that the channel already allocated for the data service is changed. Wow; Receiving the channel change request message, the base station changes the bandwidth of the already allocated radio resource according to the requested service type included in the channel change request message, and includes the changed new service type information in the change request message to send the change request message. A base station channel changing step of transmitting to a terminal station; The terminal station receiving the change request message activates a radio resource according to a new service type included in the change request message to change the radio resource of the data service, and transmits the change complete message to the base station. ; After allocating the radio resource allocated to the data service by reducing the radio resource allocated to the data service after the change completion message, the terminal station transmits a channel assignment request message to the base station to allocate a channel allocated to the voice service. A request step; The base station receiving the channel allocation request message comprises a base station channel assignment step of transmitting a channel allocation message to the terminal station in response to the channel allocation request and allocating radio resources according to a service type included in the channel allocation request message. Channel change / allocation method for the simultaneous voice / data service of the WLL system, characterized in that. The channel change request message of claim 1, A method for changing / allocating a channel for voice / data simultaneous service of a WLL system, characterized in that a reduction of an already allocated channel is required for a data service in order to secure a channel to be allocated to a newly requested voice service. 2. The terminal station of claim 1, wherein the terminal station at the terminal station change completion step comprises: If a failure occurs in the process of activating a radio resource according to a new service type included in the change request message and fails to activate the radio resource, the voice / data simultaneous of the WLL system is transmitted to the base station. How to change / assign channel for service. The method of claim 1, wherein the base station in the base station channel assignment step, If a failure occurs in the process of activating a radio resource according to the type of service included in the channel assignment request message and the allocation of the radio resource fails, the channel assignment rejection message is transmitted to the terminal station. Channel change / allocation method for simultaneous data service.