KR20060005682A - Voice call setup method in a high rate packet data transmitting wireless communication system and system thereof - Google Patents

Abstract

The present invention relates to a method for establishing a voice call in a mobile communication system. The present invention provides a call setup method that can reduce the time when a call setup of a 1: N service such as a PTT service in a CDAM 2000 1x EV-DO system providing only high-speed data.

In the method according to the present invention, the method of the present invention is a call setup method for a push-to-talk service in a high-speed data transmission wireless communication system, and a terminal may transmit a channel to transmit preamble and access data when a push-to-talk service is required. Transmitting a requesting header to a base station through an access channel at a power greater than the initial power required by the access channel, and the base station assigns access channel allocation information when the preamble and access data transmitted from the terminal are received; Comprising a message and transmitting to the terminal, and when the terminal receives the common control assignment message and transmitting the access data to the channel assigned in the common control assignment message.

EV-DO, CCAM, PLAM, Access Data, Preamble, Header

Description

VOICE CALL SETUP METHOD IN A HIGH RATE PACKET DATA TRANSMITTING WIRELESS COMMUNICATION SYSTEM AND SYSTEM THEREOF             

1 is a conceptual diagram illustrating a voice call setup in a CDMA 2000 1x EV-DO system to which the present invention is applied;

2 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a first embodiment of the present invention;

3 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a second embodiment of the present invention;

4 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a third embodiment of the present invention;

5 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a fourth embodiment of the present invention;

6 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a fifth embodiment of the present invention;

The present invention relates to a voice call setup method in a wireless communication system, and more particularly, to a voice call setup method in a high speed data transmission wireless communication system.

In general, a representative example of a wireless communication system is a mobile communication system. Such mobile communication systems have evolved in a form capable of providing data while gradually developing in a system based only on voice services. As such, a system capable of providing data services has emerged. A system capable of providing faster and higher quality services has emerged. Examples of such a system capable of transmitting high speed data include a 1x EV-DO mobile communication system and a 1x EV-DV system proposed in the 3GPP2 standard. The 1x EV-DO mobile communication system is a system that provides only high-speed data and does not consider voice service. However, methods for providing a voice service through a limited method are also discussed in the 1x EV-DO system.

As discussed above, methods for providing limited voice calls in a 1x EV-DO mobile communication system are VoIP voice services and so-called Push To Talk (hereinafter referred to as "PTT"). to be.

Next, the PTT service will be described below. Voice calls provided by wireless communication systems start from 1: 1 communication and are now evolving to support 1: N. As such, a method of supporting a 1: N voice call is a PTT method. The PTT scheme refers to a scheme developed to provide multilateral communication at low cost in a wireless communication system providing a voice service or in a 1x EV-DO type mobile communication system such as a radio. Such a PTT service is a form in which a PTT server is further provided in a general mobile communication system to perform communication.

Since the PTT service does not have a predetermined time point for the user to perform communication, a relatively long time is required when attempting to call the first call. This will be described below. When the user requests the setting of the traffic channel, the terminal establishes a traffic channel for the PTT service with the base station of the mobile communication system. In addition, since the terminal to receive the voice call must also be set up traffic, the channel should be set to the terminal that will receive the voice using the other PTT service. This is because communication is possible after the traffic channel is established on both the transmitting side and the receiving side. Therefore, very much time is required from the time when the first voice call connection is required to the time to perform voice communication between users. Therefore, developers of systems for providing PTT services have been much researched on methods for providing PTT services through faster methods.

As described above, as a method for providing a PTT service quickly, a method for more quickly establishing a traffic channel of a transmitting side has been studied. In this way, a transmission channel of the mobile communication system can be set up faster, and there is a method using a reservation access mode (Reservation Access Mode). In the mobile communication system that can use the reserved access mode, the terminal to be connected to the base station transmits a preamble at a sufficiently high power through an access channel to access the base station within a short time. Accordingly, the base station receiving the preamble sends a hash ID (hash_id) transmitted from the terminal to an early acknowledgment channel assignment message (hereinafter referred to as "EACAM") as a response (ACK) and the terminal later. A channel ID for transmitting access data is allocated and transmitted. The terminal receiving the EACAM transmits access data through the allocated reverse channel.

However, the reserved connection mode described above is a mode defined in a mobile communication system that provides voice communication and data communication. That is, the mode defined in the CDMA 2000 1x system of the 3GPP2 standard is used. Therefore, such a reservation method is not defined in a 1x EV-DO system that transmits only high-speed data. Therefore, there is a problem in that the voice call cannot be quickly connected using the reservation mode as described above.

Accordingly, an object of the present invention is to provide a method and system for quickly establishing a voice call in a high speed data transmission wireless communication system.                         

Another object of the present invention is to provide a method and system for quickly setting up a voice call by defining a reservation mode in a high speed data transmission wireless communication system.

It is still another object of the present invention to provide a method and system for defining a reservation mode in a CDMA 2000 1x EV-DO system and thereby reducing a setting time of a PTT service.

According to an aspect of the present invention, a method for establishing a call for a push-to-talk service in a high-speed data transmission wireless communication system includes: a terminal requesting a channel for transmitting a preamble and access data when a push-to-talk service is required; Transmitting a header to the base station through an access channel at a power greater than the initial power required by the access channel, and when the base station receives the preamble and the access data transmitted from the terminal, the access channel allocation information is assigned to the common control allocation message. And transmitting the access data to the channel allocated in the common control allocation message when the terminal receives the common control allocation message.

A system of the present invention for achieving the above objects is a high-speed data transmission wireless communication system for providing a push-to-talk service, accessing a header requesting a channel for transmitting a preamble and access data when a push-to-talk service is required. A terminal that transmits at a power greater than an initial power required in an access channel through a channel, and transmits the access data to a channel allocated in the common control assignment message when receiving a common control assignment message; and a preamble transmitted from the terminal. And a base station configured to transmit an access channel to the terminal by configuring the allocation information as a common control assignment message when receiving the access data.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the present invention described below, first, a reservation access mode that is not defined on the CDAM 2000 1x EV-DO standard is defined. Through the above definition, methods for quickly connecting a call will be described. In addition, the messages for the reserved access mode defined in accordance with the present invention utilize messages defined on the CDAM 2000 1x EV-DO standard. Among the above messages, necessary contents or newly defined contents according to the present invention will be described.

1 is a conceptual diagram illustrating a voice call setup in a CDMA 2000 1x EV-DO system to which the present invention is applied. Hereinafter, an operation according to voice call setup in a CDMA 2000 1x EV-DO system to which the present invention is applied will be described with reference to FIG. 1.

FIG. 1 illustrates a base station (ANTS) 101 and a mobile terminal (MT) 100 as shown. Referring to the operation of the terminal and the base station shown in FIG. 1 schematically.

< Operation of terminal >

In order to perform the reserved access mode according to the present invention, the UE transmits a preamble and a header with greater power through the reverse access channel. At this time, the header includes a data rate required by the header and a hash identifier (hash_ID). Then, when an access channel is allocated from the base station, it transmits a message for call access through this. As described above, since the operation performed in the terminal is slightly different for each of the embodiments described below, the embodiments will be described in more detail.

< Base station operation >

When receiving the preamble and the header from the terminal, the common control assignment message (hereinafter referred to as "CCAM") to specify the transmission rate of the data transmitted on the access channel and the access channel to the terminal. In a specific embodiment of the present invention, the reverse traffic channel may be allocated to a channel for transmitting access data. In addition, a power level assignment message (hereinafter referred to as "PLAN") is used to control the power of a channel through which access data is transmitted. Detailed operation of the base station will be described in more detail with reference to the accompanying drawings.

According to the present invention, by defining a reservation mode which is not defined in the existing CDMA 2000 1x EV-DO system standard, the interference effect of a large power access signal on the traffic of another terminal for a long time in a general basic access mode can be reduced. In the method according to the present invention, the reserved access mode may be classified into three stages.

First step: A terminal attempting to access transmits a preamble and a header.

Step 2: The base station detects the preamble and the header transmitted by the terminal, and allocates an uplink channel to transmit the access data by transmitting a CCAM message to the terminal that detected the preamble and the header. When the uplink channel is allocated in this way, it takes too much time using the existing downlink traffic channel. Therefore, in the present invention, call setup time is increased, so that a separate dedicated control channel may be implemented or DO rev. A downlink subsynchronous control channel of A standard is used.

Step 3: Upon receiving the CCAM message transmitted by the base station, the terminal transmits access data through the allocated uplink channel. As such, a dedicated channel for transmitting access data does not exist in the uplink according to the current EV-DO standard. Therefore, in the present invention, methods for setting channels for this will be illustrated. Each method thereof will be described in more detail in each of the embodiments described below.                     

2 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a first embodiment of the present invention. Hereinafter, a reservation access method according to a first embodiment of the present invention will be described in detail with reference to FIG. 2.

The terminal AT generates only the preamble 201 and the header 202 when a PTT service is required by the user, that is, when access is attempted, and transmits the generated data through the access channel in step 210. . The header 202 includes a data rate and a hash identifier (hash_ID) requested by the header 202. In addition, the preamble 201 and the header 202 transmit at a higher power than generally required power. In addition, in the present invention, the terminal can detect the preamble 201 and the header 202 transmitted as described above. As such, the base station that detects or receives the preamble and the header transmitted by the terminal generates the CCAM message 203. The CCAM message 203 includes information such as a channel or channel ID and a data rate to be transmitted in the reverse direction. The base station allocates a channel for transmitting access data by transmitting the CCAM message 203 generated as described above to the terminal in step 220. The terminal may then transmit the access data 204 through the assigned channel. The access data may be a short data burst (SDB) message or a DBM transmitted when a PTT service is requested.

3 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a second embodiment of the present invention. Hereinafter, a reservation access method according to a second embodiment of the present invention will be described in detail with reference to FIG. 3.                     

As described in FIG. 2, the terminal generates a preamble and a header and transmits the preamble to the base station in step 310. The base station then generates the CCAM message 301 described above, and generates a PLAM message 302 according to the second embodiment of the present invention. The PLAM message 302 according to the second embodiment of the present invention is a message including information for adjusting the power of access data to be transmitted by the terminal through an access channel according to the present invention. That is, in FIG. 3, the base station allocates some of the Walsh indexes used by the MAC to the CCAM, and simultaneously transmits the power through the PLAM message 302. Send an offset (power offset). Such an advantage of the present invention is that if the number of dedicated Walsh indexes (walsh index) is allocated, the CCAM message can be transmitted quickly. On the other hand, if the number of Walsh indexes dedicated for CCAM messages is large, the number of channels that can be allocated to traffic users transmitting traffic is reduced.

The base station generating the two messages 301 and 302 as described above transmits the two messages to the terminal using the Walsh allocated in step 320. Accordingly, the terminal transmits the access data at the allocated power in the allocated channel. By transmitting in this manner, interference on other reverse channels can be reduced. Therefore, it is possible to minimize the reduction of the total transmission capacity of the reverse link.

4 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a third embodiment of the present invention. Hereinafter, a reservation access method according to a third embodiment of the present invention will be described in detail with reference to FIG. 4.                     

The same process as in FIG. 3 described above is performed. 4 differs from the process of FIG. 3 in that the transmission time is different between the CCAM message 401 and the PLAM message 402. As shown in FIG. 4, the base station transmits the CCAM message 401 and the PLAM message 402. A method of using a subsynchronous control channel defined in the A standard is illustrated. In this scheme, the CCAM transmission time may be increased due to the transmission period 403 of the subsynchronous control channel rather than the method of using the MAC (walsh index) described above. However, the advantage is that it does not affect the number of Walsh indexes that can be allocated to a user.

5 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a fourth embodiment of the present invention. Hereinafter, a reservation access method according to a fourth embodiment of the present invention will be described in detail with reference to FIG. 5.

In FIG. 5, both the terminal AT and the terminal AT shown below are the same terminal. As shown in FIG. 5, the terminals are separated from each other in order to help understand the transmission channels since the transmission channels are different.

In FIG. 5, the terminal generates a preamble and a header as described above with reference to FIG. The base station then generates the CCAM message 502 using any of the methods described above. The base station then transmits the generated CCAM message 502 to the terminal. In the fourth embodiment of the present invention, the access channel may be used by time division or at least one traffic channel may be allocated as a channel for transmitting access data. As such, when one traffic channel is allocated to a channel for transmitting access data, there are two methods.

In a first method, at least one traffic channel is continuously set as a channel for transmitting access data, and the access data is transmitted using this channel. Therefore, when there is a request for a PTT service from the terminals to the base station, the base station may time-divided the traffic channel set for transmitting the access data to each terminal to transmit the access data. In FIG. 5, one traffic channel is divided into a plurality of time intervals, which is defined as a time slot, and a specific terminal transmits access data through the time slot. In FIG. 5, access data is transmitted using a time slot indicated by reference numeral 503.

As a second method, one of the unused traffic channels may be allocated only when receiving a preamble and a header requesting a PTT service from the terminal to transmit access data. Even in such a case, if a PTT service is continuously required, as shown in FIG. 5, one traffic channel may be divided into a plurality of time slots, and a plurality of terminals may transmit access data.

In the time division method described above, time slots are divided by allocating indexes by dividing a predetermined time interval that is regularly repeated. By sending the index and the dedicated channel assignment information to the CCAM message 502, the terminal receives this information and transmits the access data 503 in the time interval given through the assigned channel. In this case, the length of the time period must be sufficiently large in consideration of the terminal signal delay according to the cell radius so that there is no interference between the time periods.

In addition, when the terminal continues to transmit data after the access data transmission is completed, the allocated channel can be used as it is. In addition, when the traffic channel is not needed, the terminal may release the allocated traffic channel so that other terminals can use it.

6 is a signal flow diagram between a base station and a terminal for explaining a reservation access method according to a fifth embodiment of the present invention. Hereinafter, a reservation access method according to a fifth embodiment of the present invention will be described in detail with reference to FIG. 6.

In FIG. 6, when the PTT service is required, the terminal generates a preamble 601 and a header 602 to set up a traffic channel with the base station. do. When the base station receives the preamble 601 and the header 602, the base station generates the CCAM message 603 as described above. The base station transmits unique ID information of the access channel through which the access data is to be transmitted through the CCAM message 603. In addition, the access channel, which is a common channel, may be classified for each terminal by using the unique ID information. In this case, the CCAM message 603 according to the fifth embodiment of the present invention further includes a negative power offset value 604. The reduced power offset value means a value that is reduced by a certain amount of power in the power of the preamble 601 and the header 602. That is, the reduced power offset 604 is applied to correct the transmission output of the access channel. When the CCAM message 603 including the power offset is received as described above, the terminal transmits the preamble and access data through the access channel after the power is lowered by the power offset value 604.

In addition, a power control bit transmitted through a separate power control channel 605, for example, a common power control channel (CPCCH), from the time point at which transmission of an access channel is started. It is possible to adjust the transmission output of the access data using. Accordingly, FIG. 6 illustrates a power control bit as shown by reference numeral 605 and illustrates that power of a channel for transmitting access data is controlled according to the power control bit. In this case, if the power control is performed in the reverse traffic channel, the power control may be performed according to the power control bit. In addition, the power control step size in the preamble section transmitted before the access data may be applied separately from the data section.

As described above, the present invention defines a reservation mode that is not defined in the CDMA 2000 1x EV-DO system, and thus, it is possible to shorten the call connection time by quickly attempting to connect a call when a PTT service is required. have. In addition, in the present invention, it is possible to detect the preamble and the header for a short period, thereby minimizing the influence of interference, and has the advantage of reducing the influence on other traffic channels through power control.

Claims (2)

A call setup method for a push-to-talk service in a high speed data transmission wireless communication system, The terminal transmits a header requesting a channel for transmitting the preamble and the access data when the push-to-talk service is requested to the base station with a power greater than the initial power required in the access channel through the access channel, When the base station receives the preamble and the access data transmitted from the terminal, transmitting the access channel to the terminal by configuring allocation information as a common control allocation message; And when the terminal receives the common control assignment message, transmitting the access data through a channel allocated in the common control assignment message. In the high speed data transmission wireless communication system for providing a push-to-talk service, When a push-to-talk service is requested, a header requesting a channel for transmitting a preamble and access data is transmitted through an access channel at a power greater than the initial power required in the access channel, and the common control assignment is received when a common control assignment message is received. A terminal for transmitting the access data through a channel allocated in the message; And a base station configured to transmit an access channel to the terminal by configuring allocation information as a common control assignment message when receiving the preamble and the access data transmitted from the terminal.

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