KR20070080541A - Information transmitting method in mobile communication system - Google Patents

Abstract

An information transmission method in a mobile communication system is provided to be capable of notifying a base station of particular information through preamble transmission when a terminal uses an RACH(Random Access Channel), while the base station can allocate efficient radio resources to the terminal according to the particular information, thus delay time in case of data transmission of the terminal is reduced. Grouping information is received from a base station(20)(S10). A terminal(10) selects one signature and one RACH occasion from the grouping information, and transmits a preamble to the base station(S11,S12). The terminal receives radio resources allocated by the base station based on the preamble(S13). The terminal transmits uplink data to the base station by using the received radio resources(S14).

Description

Information transmission method in mobile communication system {INFORMATION TRANSMITTING METHOD IN MOBILE COMMUNICATION SYSTEM}

1 is a network structure of the conventional E-UMTS mobile communication system to which the present invention is applied

2 is a diagram illustrating each layer of a control plane of a wireless protocol.

3 is a diagram illustrating each layer of a user plane of a wireless protocol.

4 is a diagram illustrating an example in which a base station groups total RACH opportunities according to a specific purpose in the present invention.

5 is a diagram illustrating a concept of grouping a base station by combining a signature and a RACH opportunity in the present invention.

FIG. 6 is a diagram illustrating an example of actually grouping a combination cause and establishment of CQI information in FIG. 5; FIG.

7 is a view showing the overall signal flow of the information transmission method in a mobile communication system according to an embodiment of the present invention.

******* Description of the symbols for the main parts of the drawing ********

10: UE (UE) 20: base station (eNode-B)

The present invention relates to an Evolved Universal Mobile Telecommunications System (E-UMTS) system, and more particularly, to a method for transmitting information using a preamble of a random access channel (RACH).

1 is a network structure of an Evolved Universal Mobile Telecommunications System (E-UMTS), which is a mobile communication system to which the present invention and the present invention are applied.

The E-UMTS system is an evolution from the UMTS system and is currently undergoing basic standardization work in 3GPP. The E-UMTS system may be referred to as a Long Term Evolution (LTE) system.

E-UMTS network is divided into E-UTRAN and Core Network (CN). The E-UTRAN consists of a user equipment (UE), a base station (hereinafter abbreviated as eNode B or eNB), and an access gateway (Access Gateway: AG) located at an end of a network and connected to an external network.

The AG may be divided into a part for processing user traffic and a part for processing control traffic. At this time, the AG for processing the user traffic and the AG for controlling traffic may communicate with each other using a new interface. One or more cells may exist in one eNode B (eNB), and an interface for transmitting user traffic or control traffic may be used between the eNode Bs. The CN may be configured as a node for user registration of AG and other UEs, and the like. In addition, an interface for distinguishing an E-UTRAN and a CN may be used in the UMTS of FIG. 1.

Layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) reference model, which is widely known in communication systems. (Second layer) and L3 (third layer). Among them, the physical layer belonging to the first layer provides an information transfer service using a physical channel, and a radio resource control (RRC) layer located in the third layer includes a terminal and a terminal. It controls radio resources between manganeses. To this end, the RRC layer exchanges RRC messages between the terminal and the network. The RRC layer may be distributed in network nodes such as an eNode B and an AG, or may be located only in the eNode B or an AG.

FIG. 2 illustrates a structure of a radio interface protocol between a terminal and a UTRAN (UMTS Terrestrial Radio Access Network) based on the 3GPP radio access network standard. The wireless interface protocol of FIG. 2 consists of a physical layer, a data link layer, and a network layer horizontally, and a user plane for transmitting data information vertically. And Control Plane for Signaling. The protocol layers of FIG. 2 may be divided into L1 (first layer), L2 (second layer) and L3 (third layer) based on the lower three layers of the OSI reference model well known in a communication system.

Hereinafter, each layer of the wireless protocol control plane of FIG. 2 and the wireless protocol user plane of FIG. 3 will be described.

The physical layer, which is the first layer, provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to the upper medium access control layer through a transport channel, and data between the medium access control layer and the physical layer moves through the transport channel. Then, data is moved between different physical layers, that is, between physical layers of a transmitting side and a receiving side through physical channels.

The medium access control (MAC) layer of the second layer provides a service to a radio link control layer, which is a higher layer, through a logical channel. The radio link control (RLC) layer of the second layer supports reliable data transmission. The function of the RLC layer may be implemented as a functional block inside the MAC. In this case, the RLC layer may not exist. The PDCP layer of the second layer uses a header compression function to reduce unnecessary control information so that data transmitted using an IP packet such as IPv4 or IPv6 can be efficiently transmitted in a relatively low bandwidth wireless section. Perform.

The radio resource control (RRC) layer located at the top of the third layer is defined only in the control plane, and the configuration, reconfiguration and release of radio bearers (RBs) are performed. It is responsible for controlling logical channels, transport channels and physical channels. In this case, RB means a service provided by the second layer for data transmission between the terminal and the UTRAN.

A downlink transmission channel for transmitting data from a network to a UE includes a BCH (Broadcast Channel) for transmitting system information and a downlink shared channel (SCH) for transmitting user traffic or control messages. Traffic or control messages of a downlink multicast or broadcast service may be transmitted through a downlink SCH or may be transmitted through a separate downlink multicast channel (MCH). Meanwhile, the uplink transmission channel for transmitting data from the UE to the network includes a RACH (Random Access Channel) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or control messages.

Hereinafter, the RACH will be described in detail.

In general, the RACH is used for acquiring radio resources when the terminal synchronizes time with the network or when the terminal transmits data in uplink when there is no uplink radio resource for transmitting the corresponding data.

As an example, it is assumed that the terminal first approaches the new cell by turning on the power. In this case, the UE will generally synchronize the downlink and receive system information from the cell to which the UE is trying to access. After receiving the system information, the terminal should transmit a connection request message to the network for RRC access. However, the terminal uses the RACH because the time synchronization with the current network is not matched and uplink radio resources are not secured. That is, the UE requests a radio resource for transmitting an access request message to the network using the RACH. The base station receiving the radio resource request allocates an appropriate radio resource to the terminal to transmit an RRC access message, and the terminal may transmit the RRC access message to the network through the allocated radio resource.

As another example, suppose that a terminal establishes an RRC connection with a network. In this case, the terminal receives radio resources according to radio resource scheduling of the network, and transmits data to the network through the allocated radio resources. However, if there is no more data to be transmitted in the buffer of the terminal, the network will no longer allocate an uplink radio resource to the terminal. This is because it is inefficient to allocate uplink radio resources to a terminal having no data to transmit. Here, the buffer status of the terminal is reported to the network periodically or occurrence of an event. If new data is generated in the buffer of the terminal having no radio resource, the terminal uses the RACH since there is no radio resource of the currently allocated uplink. That is, by using the RACH, the UE requests a radio resource required for data transmission from the network.

The following is a description of the RACH (Random Access Channel) of WCDMA.

The RACH channel is used for transmitting a short length of data upwards, and some RRC messages such as RRC connection request message, cell update message, and URA update message are also used. It is sent on the RACH. A logical channel common control channel (CCCH), a dedicated control channel (DCCH), and a dedicated traffic channel (DTCH) may be mapped to the RACH, and the RACH is mapped to a physical channel physical random access channel (PRACH).

When the UE MAC instructs PRACH transmission to the UE physical layer, the UE physical layer first selects one access slot and one signature and transmits a PRACH preamble upward. The preamble is transmitted during an access slot duration of 1.33 ms length, and one of the 16 signatures is selected and transmitted during the first predetermined length of the access slot.

When the preamble is transmitted from the terminal, the base station transmits a response signal through a downlink physical channel acquisition indicator channel (AICH). The AICH transmitted in response to the preamble transmits the signature selected by the preamble during the first predetermined length of the access slot corresponding to the access slot to which the preamble is transmitted. At this time, the base station transmits a positive response (ACK) or a negative response (NACK) to the terminal through the signature transmitted by the AICH. If the ACK is received, the terminal transmits a message part of 10 ms or 20 ms in length using an OVSF code corresponding to the transmitted signature. If the NACK is received, the terminal MAC instructs the terminal physical layer to transmit the PRACH again after a suitable time. On the other hand, if the AICH corresponding to the previously transmitted preamble is not received, the terminal transmits a new preamble with a power higher than the previous preamble after the predetermined access slot.

Meanwhile, the CQI information is information provided by the terminal to the base station by measuring the state of the downlink channel of the current cell. The base station performs downlink radio resource scheduling through the CQI information provided by the terminal. For example, suppose the value of CQI is from 1 to 10. At this time, 1 means the worst state channel state, 10 means the best state channel state.

If the terminal transmits the CQI information of 10 to the base station, the base station determines that the current downlink channel state is good, and will transmit data to the terminal at a higher data rate (bit rate). On the contrary, when the terminal transmits CQI information of 1 to the base station, the base station determines that the downlink channel state of the terminal is not good, and transmits data at a low data rate to the terminal. The transmission criterion of the CQI information informs in advance the condition that the base station reports to the terminal periodically or occurrence of an event.

As described above, when using the RACH, the UE first selects one signature and one access slot and then transmits a preamble upward. After receiving the ACK for the preamble from the base station, the terminal transmits a message portion to the base station. As described above, in order to inform the base station of specific information by using the RACH, the terminal needs to perform both a preamble transmission process, an ACK reception process, and a message portion transmission process. There was a waste of resources.

Accordingly, an object of the present invention is to provide a method for transmitting information in a mobile communication system that can prevent waste of radio resources when the terminal uses the RACH and can reduce a delay of information transmission.

In order to achieve the above object, an information transmission method in a mobile communication system according to an embodiment of the present invention includes the steps of receiving grouping information from a base station; Selecting one signature and one RACH opportunity from the grouping information and transmitting a preamble to a base station; Receiving a radio resource allocated by a base station based on the preamble; And transmitting uplink data to a base station using the received radio resource.

Advantageously, said grouping information comprises a signature group and a RACH opportunity group divided according to specific information or includes a group consisting of a combination of signature and RACH opportunity. The grouping information is transmitted via system information or paging message.

Preferably, the specific information used as a criterion for grouping the signature and the RACH opportunity may be the same as or different from each other.

Preferably, the specific information includes information on the purpose of use of the RACH, CQI information, request amount information of radio resources, and reason for connection. The purpose of using the RACH includes an initial access, handover, synchronization maintenance, connection release and radio resource request of the terminal. In addition, the CQI information is a value indicating the channel status of the downlink, the radio resource request amount represents the buffer status of the terminal, the connection reason is the terminal is an emergency call, the terminal in idle state is moved to the active state and the terminal It indicates the movement from the disconnected state to the active state.

Preferably, the base station may dynamically change the grouping information, and the changed grouping information is transmitted to the terminal through a system information or a paging message.

In order to achieve the above object, an information transmission method in a mobile communication system according to an embodiment of the present invention includes the steps of: transmitting a signature, a RACH opportunity, and a grouping information that is experienced; Receiving a preamble from the terminal; Allocating an appropriate radio resource to a terminal based on the preamble; And receiving data transmitted by the terminal using the radio resource.

Preferably, the grouping information is transmitted via system information or paging message.

Advantageously, said grouping information comprises a signature group and an RACH opportunity group divided according to specific information, or includes a combination of signature and RACH opportunity.

Preferably, the base station receiving the preamble determines which group the corresponding signature and the RACH opportunity belong to, and allocates an appropriate radio resource.

The present invention is implemented in a mobile communication system such as UMTS. However, the present invention can also be applied to communication systems operating according to other standards. Hereinafter, preferred embodiments of the present invention will be described in detail.

The present invention proposes a method in which the UE informs the base station of predetermined information through a transmission timing (opportunity) of the preamble signature and the RACH, thereby reducing a delay time until data transmission and efficiently using uplink radio resources. To this end, the present invention uses signatures and transmission opportunities according to specific information.

In one embodiment, the present invention relates to one signature and one resource among a group of signatures divided into specific information and signatures grouped according to the first information in the RACH resource group and transmission opportunities grouped according to the second information. The preamble can be transmitted by selecting.

Preferably, the specific information is information on a purpose of use of the RACH, CQI information, request amount information of a radio resource, and establishment cause. For example, the purpose of using the RACH is initial access, handover, synchronization maintenance, connection release and radio resource request. The CQI information is a value representing the channel state of the downlink. The radio resource request amount indicates a buffer state of the terminal and may indicate 50 bits, 100 bits, 200 bits, and the like. The connection reason indicates an emergency call of the terminal, an idle state of the terminal to move to an active state, and a movement of the terminal from a detached state to an active state.

Preferably, RACH resources refer to RACH occasion. That is, the base station informs the UEs in the cell of resource information capable of using the RACH, and the resource information includes a specific frequency and a specific time. The resource information also includes a period value of the RACH opportunity.

In another embodiment, the present invention not only uses signatures grouped according to the first information and transmission opportunities grouped according to the second information, but also selects one from a group consisting of a combination of signature and RACH opportunities and combinations thereof. Can be transmitted. In the above embodiment, one signature always has the same meaning (information), but in this embodiment, one signature may have a different meaning (information) depending on the transmission opportunity to be combined.

First, a method of transmitting a preamble by selecting one signature and one resource among transmission groups grouped according to the first information and transmission opportunities grouped according to the second information will be described.

1. Signature Selection

The base station groups the entire signatures according to a particular purpose. Information about the grouped signatures is transmitted to the terminal through system information or a paging message. Therefore, when using the RACH, the terminal selects one group from among the signature groups divided into specific information according to the state of the terminal. Once one signature group is selected, the UE randomly selects one signature from the group.

For example, suppose you have a total of 64 signatures. At this time, each signature is assigned a number from 0 to 63. In this case, it is assumed that the base station uses the purpose of using the RACH as specific information that is a standard for grouping. Accordingly, group 1 is grouped for initial access, group 2 for handover, group 3 for synchronization, group 4 for disconnection, and group 5 for requesting radio resources. . The base station then appropriately maps the entire signatures to each group.

That is, the group 1 has signatures from 0 to 11, the group 2 from 12 to 23, the group 3 from 24 to 35, the group 4 from 36 to 47, and the group 5 Has signatures 48-63. As described above, information about grouped signatures (grouping information) according to the purpose of using the RACH is transmitted to the terminal through system information or a paging message.

Accordingly, if the purpose of the RACH is for handover, the terminal selects group 2 according to the set grouping information and then randomly selects one of the signatures 12 to 23 mapped to the group 2.

The base station can also dynamically change the grouping information. That is, if a particular group among the groups of signatures is used a lot by terminals in the cell, the base station may map more signatures to the corresponding group. For example, group 4 has 12 signatures, and group 5 has 16 signatures. If the frequency of use of the UE in the cell is low in group 4 and high in group 5, the base station may reduce the number of signatures in group 4 and increase the number of signatures in group 5. The change information of the signature grouping is transmitted from the base station to the terminal through system information or a paging message.

2. Select RACH Occasion

As shown in Figure 4, the base station first groups the total RACH opportunities according to a particular purpose. The specific purpose may be the same as or different from the specific information used as a criterion for grouping the signatures described above.

For example, signatures may be grouped according to the purpose of use of the RACH, RACH opportunities may be grouped according to CQI information, or both signature and RACH opportunity may be grouped according to the purpose of use of the RACH. Group information on the grouped RACH opportunity is transmitted to the terminal through system information or a paging message. Accordingly, when the terminal uses the RACH, one group is selected from among groups of RACH opportunities according to the state of the terminal. If more than one RACH opportunity is included in the selected group, the UE randomly selects one RACH opportunity in the group. A detailed example of the above invention is as follows.

The base station uses the CQI information as specific information to group the RACH opportunities. For example, group A groups the channel in a very poor state, group B groups the channel in a good state, and group C groups the channel in a very good state. The base station then properly maps the opportunities of RACH to the groups.

Information grouped according to the CQI information as described above is transmitted to the terminal through a system information or a paging message. Therefore, if the channel state of the UE is not very good, the UE selects Group A according to the set grouping information, and if Group A includes two or more RACH opportunities, randomly selects one RACH opportunity.

The base station may also dynamically change the grouping information. That is, the grouping information changed in the base station every cycle of RACH opportunities or multiples of the period is transmitted to the UE through system information or a paging message.

The following describes a method of transmitting a preamble by selecting one of a group consisting of a combination of a signature and an RACH opportunity. In this way certain signatures will not always have the same information. For example, different information may be delivered even with the same signature depending on the opportunity of the combined RACH.

FIG. 5 illustrates a concept of grouping a base station by combining a signature and an RACH opportunity in the present invention, and FIG. 6 illustrates an example of actually grouping a combination Cause and CQI information according to the concept of FIG. 5.

As shown in Fig. 5, in one period, there are four RACH opportunities, such as A, B, C, and D. The opportunities of the RACH may be all four RACH opportunities at the same time as shown in FIG. 5, or four RACH opportunities may be distributed at different times. For example, four RACH opportunities may be aggregated as in Time 2, and four RACH opportunities as in Time 4, 5, and 6 Opportunities may be distributed. Here, the total number of signatures is assumed to be 16.

In the present embodiment, the establishment cause and CQI information are used as the grouping criteria. There are two cases of the reason for connection and the CQI information, respectively, and four groups are generated as shown in FIG. In FIG. 6, if the connection reason of the terminal is A and the CQI value is 1, the terminal randomly selects one value from the third group including C5 to C9 and D0 to D8. C5 means C's RACH opportunity and signature 5.

As mentioned above, one signature and one RACH opportunity do not always represent the same information. For example, signature 10 may carry different information depending on which RACH opportunities are combined. Also, different information is delivered depending on which signature the RACH opportunity A is also combined with.

The information grouped by the combination of the signature and the RACH opportunity is also transmitted to the terminal through the system information or the paging message.

7 shows an overall signal flow of an information transmission method in a mobile communication system according to an embodiment of the present invention.

As shown in FIG. 7, the base station 20 groups all the signatures and the RACH opportunities according to specific purposes, and informs the terminal 10 of the information about the signatures and the paging message (S10).

The terminal 10 selects one signature and one RACH opportunity from among groups of signature and RACH opportunities according to the configuration of the base station 20 or selects one of a group consisting of a combination of signature and RACH opportunities (S11). ). Using the example described above, one value is selected from the third group containing C5 to C9 and D0 to D8.

The terminal 20 transmits the preamble to the base station 20 through the selected signature and the RACH opportunity (S12).

The base station 20 receiving the preamble determines which group the corresponding signature and the RACH opportunity belong to, and allocates an appropriate radio resource to the terminal 10 by scheduling a radio resource according to the result (S13). For example, if the terminal 10 used a group of signatures for initial access, and the RACH opportunity is grouped with a radio resource request amount of 100 bits, the base station 20 determines the appropriate radio resource based on the information. Assign to (10).

Accordingly, the terminal 10 having received the appropriate radio resource from the base station 20 transmits uplink data to the base station 20 by using the corresponding radio resource (S14).

As described above, according to the present invention, when the terminal uses the RACH, the terminal informs the base station of specific information through preamble transmission, and the base station allocates an efficient radio resource for data transmission to the terminal according to the specific information. There is an effect that can reduce the delay time and prevent waste of radio resources.

In addition, although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (14)

Receiving grouping information from a base station; Selecting one signature and one RACH opportunity from the grouping information and transmitting a preamble to a base station; Receiving radio resources allocated by a base station based on the preamble; And transmitting uplink data to a base station by using the received radio resource. The method of claim 1, wherein the grouping information is A preamble transmission method in a mobile communication system comprising a signature group and an RACH opportunity group divided according to specific information. The method of claim 1, wherein the grouping information is And a group consisting of a combination of a signature and an RACH opportunity. The method of claim 1, wherein the grouping information is A method of transmitting a preamble in a mobile communication system, characterized in that it is transmitted through system information or a paging message. The method of claim 2, wherein the specific information used as a criterion for grouping the signature and the RACH opportunity may be the same as or different from each other. The method of claim 2, wherein the specific information is A method of transmitting a preamble in a mobile communication system, comprising information on a purpose of use of a RACH, CQI information, request information of radio resources, and a reason for connection. The method of claim 6, wherein the purpose of using the RACH is A preamble transmission method in a mobile communication system comprising an initial access, handover, synchronization maintenance, termination of connection and radio resource request of the terminal. The method of claim 6, wherein the CQI information is A value indicating a downlink channel state, wherein the radio resource request amount indicates a buffer state of the terminal, and the connection reason is that the terminal is an emergency call, the terminal is in an idle state, moves to an active state, and the terminal is active in an unconnected state. A method of transmitting a preamble in a mobile communication system, characterized by indicating movement to a state. The method of claim 6, wherein the base station The method of claim 1, wherein the grouping information can be changed dynamically. The method of claim 9, wherein the changed grouping information is A method of transmitting a preamble in a mobile communication system, characterized in that transmitted to the terminal through a system information or a paging message. Transmitting the signature, the RACH opportunity, and the grouping information described to the terminal; Receiving a preamble from the terminal; Allocating an appropriate radio resource to a terminal based on the preamble; And receiving data transmitted from the terminal by using the radio resource. The method of claim 11, wherein the grouping information is A method of transmitting a preamble in a mobile communication system, characterized in that it is transmitted through system information or a paging message. The method of claim 11, wherein the grouping information is A method for transmitting a preamble in a mobile communication system, characterized in that the group is composed of a signature group and a RACH opportunity group divided according to specific information, or a combination of a signature and a RACH opportunity. 12. The method of claim 11, wherein the base station receiving the preamble is A method for transmitting a preamble in a mobile communication system, characterized by determining which group the signature and the RACH opportunity belong to, and allocating an appropriate radio resource.

Images