KR20080015704A - Method and apparatus for sending state transition indication in mobile communication system supported voice over internet protocol - Google Patents

Abstract

A method for sending a voice packet state by a terminal in a mobile communication system and a device are provided to enable a UE(User Equipment) to transmit information on state alteration to a node B by using reference sizes defined according to a mode of a CODEC(Coder Decoder) and size of a VoIP(Voice over Internet Protocol) packet, thereby simplifying signaling between systems in accordance with VoIP packet transmission. A state of a voice packet to be transmitted is determined by using at least more than one reference defined according to a mode of a CODEC of a UE(410)(420,425). If a state of the current voice packet to be transmitted is different from the determined state of the voice packet, information indicative of a changed state of the voice packet is transmitted to a scheduler of a node B(415)(430,435). Transmission resources corresponding to the information are allocated from the scheduler, and the voice packet is transmitted(440,445).

Description

METHOD AND APPARATUS FOR SENDING STATE TRANSITION INDICATION IN MOBILE COMMUNICATION SYSTEM SUPPORTED VOICE OVER INTERNET PROTOCOL}

1 is a diagram illustrating an example of a structure of a next-generation mobile communication system to which the present invention is applied.

2 is a diagram illustrating characteristics of a VoIP packet to which the present invention is applied.

Figure 3 is a schematic illustration of the overall operation according to the VoIP packet state in accordance with the present invention.

4 illustrates signaling of an entire system according to a VoIP packet in accordance with the present invention.

5 is a view for explaining a condition change information generation condition in accordance with the present invention.

6A-6C illustrate the format of state change information in accordance with the present invention.

7 is a view for explaining the operation of the terminal according to the first embodiment of the present invention.

8 is a view for explaining the operation of the terminal according to the second embodiment of the present invention. 9 is a view for explaining the operation of the terminal according to the third embodiment of the present invention.

10 is a diagram illustrating a format for transmitting state change information in-band according to a third embodiment of the present invention.

11 is a view for explaining the operation of the terminal according to the fourth embodiment of the present invention.

12 is a diagram schematically illustrating a structure of a terminal device to which the present invention is applied.

The present invention relates to a mobile communication system, and more particularly, to a method and apparatus for a terminal to transmit information about a state change to a scheduler when providing a voice packet service.

UMTS (Universal Mobile Telecommunication Service) system is based on the European mobile system Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), and Wideband Code Division Multiple Access: Third generation asynchronous mobile communication system using " CDMA. &Quot;

The 3rd Generation Partnership Project (3GPP), which is in charge of UMTS standardization, is discussing Long Term Evolution (LTE) as the next-generation mobile communication system of the UMTS system.

LTE is a technology that implements high-speed packet-based communication with a transmission rate of up to 100 Mbps, aiming for commercialization in 2010. To this end, various schemes are discussed. For example, a scheme of reducing the number of nodes located on a communication path by simplifying a network structure, or approaching wireless protocols as close as possible to a wireless channel are under discussion.

1 illustrates an example of a structure of a next generation (Evolved) UMTS mobile communication system to which the present invention is applied.

Referring to FIG. 1, as illustrated, an Evolved UMTS Radio Access Network (hereinafter referred to as an “E-UTRAN”) 110 is an Evolved Node B (hereinafter referred to as “ENB” or “Node B”). It is simplified to a two node structure of 120, 122, 124, 126, and 128 and an anchor node 130, 132. The user equipment (hereinafter referred to as "UE") 101 is connected to the Internet Protocol (hereinafter referred to as "IP") network by the E-UTRAN 110.

The ENBs 120 to 128 correspond to Node Bs of the existing UMTS system and are connected to the UE 101 by a radio channel. Unlike the existing Node B, the ENBs 120 to 128 play a more complex role. LTE collects the context information of UEs to support all user packets through a shared channel, including real-time services such as Voice over IP (VoIP), which transmits voice packets over the Internet protocol. You need a device for scheduling. ENBs 120-128 are responsible for this scheduling.

Throughout this specification, the common channel is a High Speed Packet Data Shared Channel (HS-PA) of High Speed Downlink Packet Access (HSDPA), in which user packets are transmitted. PDSCH '), or Enhanced Enhanced Dedicated Physical Data Channel (E-DPDCH) for enhanced uplink dedicated channel (E-DCH). It means a channel that plays a role.

Similar to the HSDPA or the mobile communication system supporting the E-DCH service, a hybrid ARQ (HARQ) scheme is performed between the ENBs 120 to 128 and the UE 101 in the LTE system. do.

First, the HARQ technique is a technique of increasing the reception success rate by soft combining with retransmitted data without discarding previously received data. In more detail, the HARQ receiver determines whether there is an error in a received packet, and according to whether the error exists, a HARQ positive acknowledgment signal (hereinafter referred to as HARQ ACK) or a HARQ negative acknowledgment. Acknowledgment (hereinafter referred to as HARQ NACK) signal is transmitted to the transmitting side. Therefore, the transmitter performs retransmission of the HARQ packet or transmission of a new HARQ packet according to the HARQ ACK / NACK signal. And, the HARQ receiving side reduces the probability of error by soft combining the retransmitted packet with the previously received packet.

However, since the HARQ alone cannot satisfy the requirements of various Quality of Service (hereinafter referred to as 'QoS'), an outer ARQ may be performed in a higher layer, and the separate ARQ may be performed. (Hereinafter, referred to as 'outer-ARQ') may also be performed between the terminal 101 and the ENBs 120 to 128. In order to realize transmission speeds of up to 100 Mbps, LTE systems are expected to use Orthogonal Frequency Division Multiplexing (OFDM) as the radio access technology in the 20 MHz bandwidth. In addition, an adaptive modulation & coding (AMC) scheme that determines a modulation scheme and a channel coding rate according to the channel state of the terminal will be applied.

Hereinafter, a mobile communication system to which a base station scheduling to which the present invention is applied will be briefly described. In particular, the reverse packet transmission and reception in the system to which the base station scheduling is applied goes through the following process.

The base station collects information necessary for scheduling, such as buffer status and channel condition, from the terminals, and the scheduler of the base station allocates uplink transmission resources to the terminals with reference to the information necessary for the scheduling, and then allocates the allocated transmission resource information to the terminal. Signal them.

In this regard, in an OFDM-based communication system to which the present invention is applied, a specific frequency band for a specific period is used as a transmission resource, and a base station uses the transmission channel information signaling for a predetermined channel. For convenience of description, a channel through which a control message containing transmission resource information is transmitted is called a grant channel. Accordingly, when the terminal receives the transmission resource information through the grant channel, the terminal transmits the packet in the reverse direction using the signaled transmission resource.

In the system to which the base station scheduling is applied as described above, in order to transmit one packet in the reverse direction, the terminal reports the buffer state / channel state to the base station scheduler and receives transmission resources from the base station. Transmission and reception of control information is involved.

Although the above processes are preferable in terms of efficient use of radio resources, they are not suitable for services such as VoIP in which small packets are continuously generated. That is, signaling overhead due to the transmission and reception of the separate control information is continued. There is a problem that occurs.

In other words, there is a need for a specific and efficient transmission resource allocation method for supporting a real-time voice service such as VoIP in the newly proposed LTE mobile communication system. In addition, there is a need for a detailed processing process for a small and continuously occurring packet and an efficient transmission resource allocation scenario of transmission resources.

Accordingly, the present invention, which was devised to solve the problems of the prior art operating as described above, provides a method and apparatus for transmitting information regarding a state change by a terminal when providing a voice packet service in a mobile communication system.

In another aspect, the present invention provides a method and apparatus for determining, by a terminal, a state of a voice packet and reporting information indicating the determined state to a scheduler in a mobile communication system supporting a voice packet service.

The present invention relates to a method in which a mobile station is allocated a transmission resource in a mobile communication system supporting a voice packet service, using at least one criterion determined according to a codec mode of the mobile station. Determining, when the state of the voice packet is changed, transmitting information indicating the changed state of the voice packet to a scheduler of a base station, receiving a transmission resource corresponding to the information from the scheduler, and receiving the voice. And transmitting a packet.

The present invention relates to a terminal device supporting a voice packet service in a mobile communication system, wherein at least one criterion for distinguishing a different period and a different packet size received from a base station is a size of a voice packet stored in a transmission buffer. A control unit for determining a state change of the packet by comparing the control unit, a state change information generation unit for configuring and transmitting state change information under control of the control unit, and a transmission resource allocated from the base station in response to the state change information. And a grant channel processor for controlling to transmit the voice packet of the transmission buffer.

Hereinafter, the operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily flow the gist of the present invention, the detailed description thereof will be omitted.

Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

In addition, although the LTE system is used as an example in describing the present invention, the present invention can be applied to all mobile communication systems to which base station scheduling is applied without any addition or subtraction.

In the LTE system supporting the real-time voice service to which the present invention is applied, it can be seen that VoIP generally generates packets of a relatively constant size every 20 msec. Accordingly, the present invention intends to propose a method to service VoIP without using the buffer status report and explicit transmission resource allocation process used in the existing mobile communication system using these characteristics.

In other words, in a preferred embodiment of the present invention, when providing a service in which the packet size and generation period are known, such as VoIP in the reverse direction, instead of reporting the packet size and generation cycle to the base station whenever a new packet is generated The present invention provides a method and apparatus for efficiently using uplink transmission resources limited on the radio by signaling information to a base station from which a terminal can infer the generation frequency and size of a packet.

2 is a diagram illustrating characteristics of a VoIP packet according to the present invention.

Hereinafter, the VoIP packet is used interchangeably with the VoIP traffic. In particular, the VoIP packet is a term defined for meaning in a generated voice packet, and the VoIP traffic is a term defined for meaning in a VoIP packet transmitted continuously. Obviously, the series of VoIP packets and the VoIP traffic are the same terms.

Referring to FIG. 2, the UMTS-based mobile communication system includes using an adaptive multi rate (AMR) codec according to support of VoIP traffic. In addition, header compression is essential in mobile communication systems to reduce overhead caused by headers. Accordingly, the mobile communication system supporting the VoIP service according to the present invention is characterized by using an AMR codec and transmitting and receiving VoIP traffic to which header compression is applied.

In the present invention, the header compression apparatus can transmit the header of the first few packets without compressing the header. Hereinafter, in the present invention, a section in which the header packet is not compressed is referred to as a 'transient state' (205). In the transient state, relatively large packets having a size of about 800 bits are generated.

The header compression apparatus begins to compress the header of the VoIP packet when the transient state ends. When the user generates the actual voice data as a 'talkspurt period state', the size of the packet generated in the call state 210 is about 300 bits (225). The size of the compressed header varies slightly depending on whether or not the field value of the header is changed. Generally, the size of the compressed header is 24 bits, and sometimes a larger size. The packet generation period of the transient state 205 and the call state 210 is 20 msec.

In addition, in the 'silent period state' 215 in which the user does not generate voice data, a packet 230 having a size of about 100 bits is generated. The mute packet generation period is 160 msec.

In summary, in VoIP, the packet size and packet generation period vary depending on the state, but within the same state, the packet generation period is constant and the size of the generated packet is substantially constant.

For example, in the call state 210, each packet generation period is the same as 20 msec, but a packet having a larger size than a silent packet having a size of about 300 bits is generated.

Considering the characteristics of the VoIP traffic as described above, the present invention proposes the following operations of the terminal and the base station.

▶ When the call is set up, the terminal receives information to detect a change in the state of the VoIP traffic from the base station.

The terminal detects a state change of the VoIP traffic based on the information, signals the detected state change to the base station, and does not perform a separate buffer state report.

▶ The base station infers the packet generation situation of the terminal according to the current state of the signaled terminal, and allocates an appropriate transmission resource accordingly.

3 schematically illustrates a process of generating information related to a state of a packet by a terminal according to the present invention.

Referring to FIG. 3, a packet having a size of about 300 bits is generated every 20 msec in a call state 315 and 335 in an upper layer of the terminal, and in a silent state 325 has a size of about 100 bits every 160 msec. Generate the packet.

The terminal determines which packet the packet generated at any time belongs to based on a predetermined criterion as described above. If it is determined that the state of the generated packet is changed, the base station transmits indication information indicating that the state of the packet is changed, that is, state transition information 320, 330, 340, 350 according to the present invention. do.

In this case, a dedicated channel allocated to a terminal may be used as a reverse channel for transmitting the state change information, or a shared channel shared by a plurality of terminals may be used. In the present invention, a case in which a random access channel is used as the shared channel will be described as an example.

Accordingly, in the present invention, the base station receives the state change information transmitted from the terminal, it characterized in that the allocation of transmission resources according to the changed state.

4 is a signal flow diagram between a terminal and a base station for transmitting and receiving state change information according to the present invention. 5 is a view illustrating a concept according to a condition for generating state change information defined according to the present invention.

4 and 5, the base station 415 is notified of parameters related to the call from the terminal when the call is set up. The call related parameter may include information such as an AMR codec mode supporting a VoIP call. The base station may derive the size of the packet to occur for each VoIP state from the VoIP codec mode.

As described above, the VoIP packet consists of an IP / UDP / RTP header and a payload. In other words, the voice frame generated from the codec is an Internet Protocol (IP) / User Datagram Protocol (UDP) / Real-time Transport Protocol (RTP) entity. It is composed of VoIP packets.

The full size of the IP / UDP / RTP header is 60 bytes based on IPv6, and the compressed header has a size of about 3 to 15 bytes. In addition, the size of the payload is defined as a constant size per codec mode. Therefore, the size of the VoIP packet has a range of values, that is, a size, depending on the codec mode.

Table 1 below shows the sizes of VoIP packets according to codec modes.

In Table 1, the AMR SID means a packet occurring in a silent period, and the rest of the codec mode means a packet occurring in a talkspurt period.

As described above, the base station can infer the size of the packet to be generated for each state from the codec mode of the VoIP.

For example, if the AMR 12.2 kbps codec mode is used for any VoIP call, a 97-byte packet occurs in the transient state of the call, a 35-47-byte packet in the busy state, and 10 in a silent state. It can be expected that a packet of size 22 bytes will occur.

Accordingly, the base station determines the 'condition change information generation condition' based on the VoIP codec mode and signals it to the terminal (420).

Here, the 'state change information generation condition' may be a size of a packet generated in an upper layer of the terminal or a generation period of a packet generated in an upper layer. Referring to the case where the size of the packet generated in the upper layer is used as the condition for generating the state change information, as shown in Table 1, the size of the packet generated in an arbitrary state for each codec mode has a certain range. The terminal may infer the state to which the packet belongs based on the size of the packet generated in the higher layer.

Here, referring to FIG. 5, the base station determines the reference size 1 535 in consideration of the size 520 of the packet to be generated in the transient state and the size 525 of the packet to be generated in the call state, and determines the size of the packet to be generated in the call state. The reference size 2 540 is defined in consideration of the size 525 and the size 530 of the packet to be generated in the silent state.

In other words, if the size of the packet generated in the terminal is greater than the reference size 1, the base station determines that it is in a transient state. If the size of the generated packet is between the reference size 1 and the reference size 2, it is defined as being in a call state. If the size of the generated packet is smaller than the reference size 2, the control unit may determine that the packet is in a silent state.

For example, in AMR 7.95 kbps codec mode, a packet of 87 bytes in transient state, a packet having a size of 25 to 37 bytes in a call state, and a packet having a size of 10 to 22 bytes in a silent state occurs. It is possible.

Therefore, the definable reference size 1 may be defined as 50, which is an arbitrary value between 87 and 37, and the reference size 2 may be defined as 23, which is an arbitrary value between 22 and 25.

As described above, the base station determines an appropriate state change information generation condition according to the codec mode of the VoIP, and then signals it to the terminal (420).

When the terminal receives the VoIP packet from the vocoder (425), that is, detects that voice data to be transmitted to the transmission buffer has occurred. In operation 430, the VoIP packet satisfies a condition for generating state change information.

In this case, the current state of the VoIP traffic to be transmitted is determined by referring to the reference sizes (reference size 1 and reference size 2) of the defined packet received from the base station. Or, it is checked whether the current state of the VoIP traffic is the same as the previous state.

In this case, if the current state of the VoIP traffic is not the same as the previous state, the condition for generating state change information is satisfied, and accordingly, the terminal configures state change information and transmits the state change information to the base station (435). The state change information reports a new state to the base station, and requests the base station to allocate a transmission resource suitable for the new state based on the state of the new terminal. The new control message may be defined as the state change information. Or it can be sent using a normal buffer status report message.

In addition, as in step 420 of the present invention, in the case of the first VoIP packet generated after the call is established, the condition for generating the state change information is always satisfied because the previous state does not exist.

Therefore, in step 435, the terminal should transmit state change information to the base station. The base station determines, with reference to the state change information, what size of transmission resource should be allocated to the terminal at what cycle, and allocates the transmission resource to the terminal through the grant channel (440). The terminal transmits the VoIP packet using the allocated transmission resource (445).

Thereafter, when the second VoIP packet arrives at the terminal (450), the terminal determines the state of the packet, compares the state with the state of the previous packet, and determines whether the state change information is generated (455).

For example, if the second packet is also a packet including the entire header, that is, if the current state is a transient state and the previous state is also a transient state, the state is not changed and there is no need to reallocate transmission resources. . Therefore, the terminal does not generate state change information.

Therefore, the base station allocates a transmission resource to the terminal based on the state change information 435 received most recently (460).

In this case, if the UE is allocated a semi-persistent transmission resource from the base station in step 440, the base station does not transmit the transmission resource allocation information in step 460. The semi-persistent transmission resource is a useful transmission resource once allocated until it is released by separate signaling, and may be usefully used for a service in which packets are periodically generated, such as VoIP.

This has the advantage of not having to perform separate signaling in response to the same information between the base station and the terminal. Therefore, it is possible to reduce the overhead of signaling processing on the radio and to save the limited transmission resources so that they can be used for other services, thereby providing an efficient transmission allocation scheme.

On the other hand, if the semi-persistent transmission resources are not allocated in step 440, the base station transmits the transmission resource allocation information (460).

Thereafter, whenever the VoIP packet generated in the upper layer arrives, the terminal checks whether a condition for generating state change information is satisfied, and if it satisfies the condition, creates and transmits state change information to the base station.

6A to 6C are diagrams for defining a message format of state change information according to the present invention.

Referring to FIG. 6A, a terminal includes an identifier of a logical channel associated with VoIP in a logical channel identifier field 605 in a message for transmitting state change information, and stores a size of a packet satisfying a condition for generating state change information in a buffer state field. After configuring the general buffer status report in 610, the configured message may be transmitted to the base station.

If the buffer status report 610 of the received message is a buffer status report for the logical channel of VoIP, the base station determines the size of the VoIP packet indicating the status of VoIP traffic, not the total data stored in the buffer. Consider. The new state of VoIP traffic is inferred from the size of the VoIP packet, and an appropriate transmission resource is allocated according to the state.

Referring to FIG. 6B, if the terminal uses a new control message containing a state that is actually changed as the state change information, the new control message includes information 615 indicating the type of control message and new state information 620 of the terminal. ), Including

For example, the state information may be defined using a predetermined bit as a state of no state, a transient state, a call state, and a mute state. In addition, the terminal may be set to a specific state by using the value of the defined bit in the new state information 620 and transmitted to the base station.

In addition, referring to FIG. 6C, the terminal may use a 1-bit indicator as the state change information. In this case, when the 1 bit is set to 1, it means that the state of the VoIP traffic has changed from the previous state.

<First Embodiment>

7 is a diagram illustrating an operation of a terminal for transmitting state change information according to the first embodiment of the present invention.

Referring to FIG. 7, in step 705, the UE performs a call setup process for supporting a base station and VoIP service (VoIP bearer establishment).

In the call setup process, the terminal receives and receives the reference size 1 and the reference size 2 defined according to the VoIP packet size from the base station (Threshold 1 and 2 acquisition). In addition, the reference size 1 and the reference size 2 may use a predetermined value instead of receiving signaling for each call setup process.

In step 710, the terminal is operating in an initial state. That is, set the 'Current State' variable to 'Null' and wait until the VoIP packet arrives from the upper layer. The 'Current State' variable used according to the VoIP service of the terminal is a variable that manages the current state of the VoIP traffic, and the terminal has one of four values: null state, transient state, call state, and mute state. Can have

When the UE receives the VoIP packet from the upper layer, that is, in step 715, that the UE detects the existence of the VoIP packet in the transmission buffer (VoIP packet arrival at transmission buffer), the size of the VoIP packet and the reference size 1 and By comparing the reference size 2, the state of the VoIP packet is determined (Evaluate Current State).

At this time, if the size of the VoIP packet is larger than the reference size 1, the current state variable is set to a transient state.

If the size of the VoIP packet is smaller than the reference size 1 and larger than the reference size 2, the state variable is set to a call state, and if the size of the VoIP packet is smaller than the reference size 2, the state variable is set to a silent state. do.

If the UE determines in step 725 that the state of the current VoIP packet is the same as the state stored in the current state and does not need to update the state variable, the UE returns to step 715 and waits for the arrival of the next packet. do. That is, since the VoIP packet delivered to the transmission buffer is the same as the previous state, the received VoIP packet is transmitted in the reverse direction through the previously allocated transmission resource without a separate buffer status report.

On the other hand, if it is confirmed that the state of the current VoIP packet is different from the state stored in the current state (Current state) proceeds to step 730.

In step 730, the terminal updates the current state (Current state) to a new state, and in step 735 configures state change information corresponding to the new state value and transmits it to the base station, and returns to step 715. The state transition indication may include, for example, an identifier of a logical channel associated with a VoIP service and information about a size of a packet causing generation of state change information.

The first embodiment of the present invention described above describes a case in which the terminal uses a shared transmission resource such as a random access channel instead of a dedicated transmission resource to transmit state change information. At this time, the transmission of the state change information may exist as a possibility to interfere with the transmission of important messages of other terminals. Since this possibility cannot be excluded, the terminal preferably transmits the state change information as few times as possible.

In addition, when changing to a state in which the transmission resources required for the transmission of the VoIP packet of the terminal is reduced, that is, the size of the generated VoIP packet is reduced, the base station determines that the state of the VoIP packet is changed through the size of the received packet. It can be inferred that it has changed. Therefore, even if the terminal does not transmit state change information, the operation is possible. However, since the allocated transmission resource is used for the transmission of the larger packet for the transmission of the first packet generated in a state where the size of the generated VoIP packet becomes small, a waste of transmission resources occurs. However, this waste of transmission resources is limited to the first packet and thus cannot be regarded as a serious problem.

In this regard, in the second embodiment, the operation of the terminal is defined as a solution to this problem.

<< second embodiment >>

In the second embodiment of the present invention, a method of transmitting state change information only when a state changes to a direction requiring more transmission resources, and omitting the transmission of state change information when changing to a state in which a request transmission resource decreases. present.

8 is a diagram illustrating an operation of a terminal according to the second embodiment of the present invention.

Referring to FIG. 8, in step 805, the UE performs a call establishment process for supporting a base station and a VoIP service (VoIP bearer establishment).

At this time, the terminal is informed from the base station of the reference size 1 and the reference size 2, which is defined by different criteria according to the size of the VoIP packet based on the mode of the AMR codec used (Threshold1 and 2 acquisition). The reference size 1 and the reference size 2 may use a predetermined value instead of signaling when setting up a call. This means that the reference size 1 and the reference size 2 according to the AMR codec mode used by the terminal can be predicted.

In step 810, the UE is operating in an initial state. The 'Current State' variable is set to 'Null' and waits until a packet arrives from an upper layer. The 'Current State' is a variable for managing the current state of VoIP traffic and may have one of four values of Null, transient state, call state, and mute state.

When the VoIP packet arrives from the upper layer in step 815, the terminal determines the state of the VoIP packet by comparing the size of the VoIP packet with reference size 1 and reference size 2 in step 820. If the size of the packet is greater than the defined reference size 1, the packet is transient. If the size of the packet is smaller than the reference size 1 and greater than the reference size 2, it is in a call state. In step 825, if the state of the current packet is the same as the state stored in the current state (Current state), the terminal returns to step 815 and waits until the next packet arrives.

On the contrary, if the state of the current packet is different from the state stored in the current state, the flow proceeds to step 830.

In step 830, the UE updates the current state to a new state, and in step 835, determines whether the newly updated state requires more transmission resources than the previous state. In the following three cases, the newly updated state requires more transmission resources than the previous state.

1. When you change from muted to call

2. When changing from silent to transient

3. If you change from a call state to a transient state

If one of the above cases occurs, that is, if the newly updated state requires more transmission resources than the previous state, the terminal proceeds to step 840, and the new update state does not require more transmission resources than the previous state. If not, return to step 815. That is, according to the second embodiment, when the newly updated state requires a smaller transmission resource than the previous state, the terminal does not report the state change to the base station.

As more transmission resources are required in step 840, the terminal configures state change information and transmits the changed state information to the base station, and then returns to step 815. The state change information may include, for example, an identifier of a logical channel associated with the VoIP service and the size of a packet causing the state change information.

<< Third Embodiment >>

In the third embodiment of the present invention, when the state is changed to require more transmission resources, the state change information is transmitted through a separate control channel, and when the state is changed to a state where the required transmission resources are reduced, the state change information is transmitted. We present a method for transmission by including in a VoIP packet.

9 is a diagram illustrating an operation of a terminal according to a third embodiment of the present invention.

9, in step 905, the UE performs a VoIP call setup process with a base station (VoIP bearer establishment).

At this time, the UE acquires the reference size 1 and the reference size 2, which are defined by different criteria according to the size of the VoIP packet based on the mode of the AMR codec used, from the base station (Threshold1 and 2 acquisition). The reference size 1 and the reference size 2 may use a predetermined value instead of signaling when setting up a call. This means that the reference size 1 and the reference size 2 according to the AMR codec mode used by the terminal can be predicted.

In step 910, the UE is operating in an initial state, and sets the 'Current State' variable to 'Null' and waits until a packet arrives from an upper layer. The 'Current State' is a variable for managing the current state of VoIP traffic and may have one of four values of Null, transient state, call state, and mute state.

When the VoIP packet arrives from the higher layer in step 915, the terminal determines the current state of the VoIP traffic using the size of the received VoIP packet and the reference size 1 and the reference size 2 in step 920.

For example, if the size of the VoIP packet is larger than the defined reference size 1, it is a transient state, and if the size of the packet is smaller than the reference size 1 and larger than the reference size 2, it is in a call state.

In step 925, if the current packet state is the same as the state stored in the current state, the terminal returns to step 915 and waits for the arrival of the next packet. On the contrary, if the state of the current packet is different from the state stored in the current state, the flow proceeds to step 930.

In step 930, the UE updates the current state to a new state, and in step 935, the UE determines whether the newly updated state requires more transmission resources than the previous state. In the following three cases, the newly updated state requires more transmission resources than the previous state.

1. When you change from muted to call

2. When changing from silent to transient

3. If you change from a call state to a transient state

If one of the above cases occurs, i.e., if the newly updated state requires more transmission resources than the previous state in step 935, the terminal proceeds to step 940, and the newly updated state is smaller than the previous state. If yes, go to Step 945.

As more transmission resources are required in step 940, the UE configures state change information and transmits the state change information to the base station through a predefined reverse channel, for example, a dedicated channel or a random access channel allocated to the UE, and then returns to step 915. do.

On the other hand, as the newly updated state requires a smaller transmission resource than the previous state, in step 945, the terminal configures state change information and includes the VoIP packet generated in the new state in the received packet. This is the same as FIG.

10 is a diagram illustrating a transmission format in which a terminal transmits state change information in a VoIP packet according to the present invention.

Referring to FIG. 10, the terminal may transmit state change information 1010 to the VoIP packet 1005 through a transmission resource allocated from the base station. The state change information may use a 1-bit indicator. In this case, when the 1 bit is set to 1, it means that the state of the VoIP traffic has changed from the previous state.

<< fourth embodiment >>

The fourth embodiment of the present invention proposes a method of releasing semi-persistent transmission resources allocated for a corresponding state after the terminal transmits state change information.

A semi-permanently allocated transmission resource is a resource allocated in advance so that the terminal can use it at a predetermined time point without going through a separate transmission resource allocation process when a packet having a similar size periodically occurs, such as the VoIP packet. Means a transmission resource. The semi-persistent transmission resource may be allocated through an upper layer message such as an RRC layer message or a MAC layer message, or may be allocated through a general scheduling channel. For example, when allocating a specific transmission resource (or set of transmission resources) to the terminal in 20 msec units for VoIP packet transmission in a call state, when the terminal transitions from the call state to the silent state, the transmission resource is released. Needs to be.

A typical procedure for allocating or releasing semi-persistent transmission resources is to transmit a physical channel signal over a predetermined forward control signal, e.g., a scheduling channel (also called an L1 / L2 control channel), or explicitly using a higher layer message. Is done.

It is obvious to both the terminal and the base station that the semi-persistent transmission resource used in the previous state and the new semi-permanent transmission resource need to be allocated when the VoIP state is changed due to the characteristics of the VoIP session. The terminal transmits the state change information to the base station. Therefore, in the fourth embodiment of the present invention, when the state change information transmitted by the terminal is successfully transmitted, the terminal and the base station implicitly release the release of the semi-persistent transmission resource used in the previous state.

11 is a diagram illustrating an operation of a terminal according to a fourth embodiment of the present invention.

Referring to FIG. 11, in step 1105, the UE establishes a VoIP session, monitors the VoIP packet occurrence in the transmission buffer, and checks whether the state has changed.

In step 1110, the UE detects that a state change occurs with a new state x. The state x may be a call state or a mute state.

In step 1115, since the terminal has changed state, the terminal configures state change information. If the state change is a change to a state requiring more transmission resources than the current state, the terminal transmits state change information through a predefined reverse physical channel. On the other hand, if the state change is a change to a state requiring less transmission resources, the terminal transmits the packet through the already allocated transmission resources as in the third embodiment. In this case, the state change can be implicitly indicated by storing the state change information in the packet and transmitting the state change information together or by transmitting a small packet through the already allocated transmission resource as in the second embodiment. The small packet may be, for example, an SID.

In step 1120, the UE transmits the state change information transmitted in step 1115 through a predetermined reverse physical channel, is stored in a VoIP packet, or is transmitted in the second embodiment. In this case, it is determined whether a state change is indicated.

If the state change information is transmitted through a predetermined reverse physical channel, the terminal proceeds to step 1130, and if the state change information is implicitly indicated by transmitting a small VoIP packet or is stored together in a VoIP packet and transmitted. Proceed to step 1225.

In step 1125, the UE determines whether the MAC PDU containing the state change information or the small VoIP packet indicating the state change has been successfully transmitted.

Meanwhile, in the LTE system, since all MAC PDUs are transmitted and received through a HARQ process, when the HARQ ACK is not received even after a predetermined number of retransmission limits, the MAC PDU is not successfully transmitted. When the HARQ ACK is received, It is determined that the MAC PDU has been successfully transmitted.

Therefore, if it is confirmed that the MAC PDU is not successfully transmitted, the UE proceeds to step 1135 and retransmits the state change information. At this time, if there is a semi-persistent transmission resource allocated for the state x, the terminal retransmits the state change information by using the semi-persistent transmission resource. Alternatively, the normal transmission resource allocation request process can be avoided by retransmitting a small VoIP packet that implicitly indicates the state change.

On the other hand, if the MAC PDU is successfully transmitted, the UE proceeds to step 1130 and checks whether there is a semi-persistent transmission resource allocated for the state x. In step 1130, if the semi-persistent transmission resource is allocated for the state x 1140 The process proceeds to release the semi-persistent transmission resource for the state x. In short, the semi-persistent transmission resource for the state x is considered to be no longer valid, and the semi-persistent transmission resource is no longer used.

In step 1145, the terminal waits for a next command, for example, a new semi-permanent transmission resource allocation command or the like from the base station or the network.

On the other hand, if the semi-persistent transmission resource for the state x has not been allocated in step 1130, the terminal immediately proceeds to step 1145 and waits for the next command from the base station or the network. The gist of the fourth embodiment of the present invention provides additional semi-persistent transmission resource release information. Instead of signaling, when transmission of information relating to a state change is completed, it is regarded as an implicit indication that the semi-persistent transmission resources allocated for the previous state are released, thereby deciding the transmission resources used for signaling of the semi-permanent transmission resource release information. It is saving. The gist of the present invention can be applied to the forward direction as it is. That is, when the state of the forward session is changed from the call state to the mute state, the base station implicitly indicates that the forward semi-permanent transmission resource of the call state is released by transmitting the SID packet using the forward semi-permanent transmission resource allocated for the call state. Can be directed.

12 is a diagram illustrating a terminal device for transmitting state change information according to the present invention.

Referring to FIG. 12, the terminal compresses a codec 1205 for generating voice data, an IP / UDP / RTP protocol entity 1210 for converting the voice data generated in the codec 1205 into a VoIP packet, and a header of the VoIP packet. Header compression device 1215, transmission buffer 1220 for storing packets until transmission, transmission and reception device 1225 for transmitting packets over a wireless channel, and receiving necessary control information, and transmission resource allocation information through grant channels. The grant channel processor 1240, the state change information generator 1235, and a controller 1230 are included.

The controller 1230 receives the 'state change information generation condition' from the upper control layer, that is, the reference size 1 and the reference size 2, and compares the size of the VoIP packet stored in the transmission buffer with the reference size 1 and the reference size 2 It is determined whether the condition for generating status change information is satisfied.

When the state change information generation condition is satisfied, the state change information generation unit 1235 is instructed to generate state change information.

The state change information generator 1235 generates state change information under the control of the controller 1230 and transmits the state change information to a base station through a predetermined reverse channel such as a reverse common channel.

The grant channel processor 1240 receives the transmission resource allocation information from the base station, and if the transmission resource is allocated, the transmission buffer 1220 controls to transmit the packet. Accordingly, the transceiver 1225 transmits the VoIP packet arriving at the transmission buffer 1220 using the allocated transmission resource.

In the present invention operating as described above in detail, the effects obtained by the representative of the disclosed invention will be briefly described as follows.

The present invention provides a system according to VoIP packet transmission by transmitting information according to a state change to a base station using reference sizes defined according to the size of the VoIP packet to be transmitted by the terminal and the mode of the codec used to support the VoIP service. It has the advantage of simplifying signaling between the liver.

In addition, according to the simplification of the signaling, there is an advantage of efficiently using a limited transmission resource.

In addition, since only the indication information according to the state change is transmitted and the existing buffer status is reported, a smaller amount of transmission resources are used than the transmission resources used.

Claims (23)

In a mobile communication system supporting a voice packet service, a method in which a terminal is allocated a transmission resource, Determining a state of a voice packet to be transmitted using at least one criterion determined according to a codec mode of the terminal; If it is confirmed that the state of the current voice packet to be transmitted is different from the determined state of the voice packet, transmitting information indicating the changed state of the voice packet to the scheduler of the base station; And transmitting the voice packet by allocating a transmission resource corresponding to the information from the scheduler. The method of claim 1, wherein the determining of the state of the voice packet comprises: Receiving, by the terminal, values of a reference size 1 and a reference size 2 for determining a state of the voice packet defined by different packet sizes with different transmission periods according to the codec mode from the scheduler; And comparing the size of the current voice packet with the reference size 1 and the reference size 2 to determine a state having a predetermined specific size. The method of claim 2, wherein the state of the voice packet, And a null state having a different transmission period and a different packet size, a transient state including an entire header, a call state including a compressed header, and a silent state. The method of claim 1, wherein the transmitting of the information indicating the changed state of the voice packet to the scheduler of the base station, And the terminal transmits the information indicating the determined state of the voice packet in a state information field of a control message and transmits the information. The method of claim 1, wherein the transmitting of the information indicating the changed state of the voice packet to the scheduler of the base station, And transmitting, by the terminal, the size of the determined voice packet to be included in a buffer status field of a logical channel. The information indicating the changed state of the voice packet, The transmission resource allocation method of the terminal, characterized in that it further comprises type information of the control message. The method of claim 5, wherein the information indicating the changed state of the voice packet, And transmitting the identifier information of the logical channel. The method of claim 1, The terminal further checks whether the determined state of the current voice packet is the same as the previous state, and further comprising the step of updating the transmission resource allocation method of the terminal. The method of claim 6, The terminal changes the current state from the silent state of 160 ms period to a call state having a compressed header of 20 ms period, or from the silent state to a transient state having a full header of 20 ms period, or from the call state And transmitting information indicating the state change of the updated voice packet to the base station in case of transition to a transient state. A terminal device supporting a voice packet service in a mobile communication system, A control unit for determining a state of the voice packet by comparing at least one criterion for distinguishing a different period received from a base station to have a different packet size from the size of the voice packet stored in the transmission buffer; A state change information generation unit for constructing and transmitting information indicating a changed state of the voice packet under the control of the controller; And a grant channel processor for controlling to transmit a voice packet of the transmission buffer through a transmission resource allocated from the base station in response to the information. The method of claim 10, wherein the terminal device, A codec for generating the voice data; An internet protocol entity configured to construct voice data generated by the codec into voice packets; And a header compression device configured to compress the header of the constructed speech packet into a speech packet having a different state by compressing the header of the configured speech packet under the control of the controller. The method of claim 10, wherein the control unit, The terminal receives the at least one criterion defined by a different packet size with a different transmission period according to the codec mode from a scheduler, and compares the voice packet to be transmitted with the at least one criterion to determine a specific state. Terminal device comprising a. The method of claim 12, wherein the control unit, And determining a specific state as one of a null state having a different transmission period and a different packet size, a transient state including an entire header, a call state, and a silent state. The method of claim 10, wherein the control unit, And controlling the state change information generator to include information indicating a changed state of the voice packet in a state information field of a control message and transmit the information. The method of claim 10, wherein the control unit, And controlling the state change information generator to include information indicating a changed state of the voice packet in a buffer state field of a logical channel. The method of claim 15, wherein the control unit, The terminal further comprises updating after checking whether the determined state of the current voice packet is the same as the previous state. The method of claim 14, wherein the control unit, And controlling the state change information generator to include information indicating a changed state of the voice packet in a state information field of a control message and further include type information of the control message. The method of claim 15, wherein the control unit, And controlling the state change information generator to include information indicating a changed state of the voice packet in a buffer state field of a logical channel and further include identifier information of the logical channel. The method of claim 16, wherein the control unit, The terminal changes the state of the current voice packet from the mute state to a call state having a compressed header of 20 ms periods, or from the mute state to a transient state having a full header of 20 ms periods, or from the call state And in case of transition to a transient state, control to transmit information indicating a state change of the updated voice packet to the base station. The method of claim 1, The terminal confirms that the transmission resource for the current voice packet is larger than the transmission resource for a previous voice packet; And transmitting information indicating the changed state of the voice packet to the scheduler by including information in a reverse control channel. The method of claim 1, The terminal confirming that a transmission resource for the current voice packet is smaller than a transmission resource for a previous voice packet; And transmitting information indicating the changed state of the voice packet to the scheduler by including the current voice packet in the current voice packet. The method of claim 1, Receiving, by the terminal, a response signal to the current voice packet including information indicating a changed state of the voice packet from the scheduler; And retransmitting information indicating the changed state of the voice packet to the scheduler according to the response signal. The method of claim 22, Checking, by the terminal, whether a semi-persistent transmission resource is allocated from the scheduler in response to the voice packet; And transmitting the semi-permanent transmission resources.

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