Method for requesting radio resource in mobile communications system

Method for requesting radio resources in mobile communication system

The present invention relates to a multimedia broadcast/multicast service (MBMS), and more particularly to a method for transmitting information to support the mobility of a terminal and providing MBMS service

Figure 1 shows the network structure of E-UMTS, which is related to the mobile telecommunication system of both the related technology and the present invention. The E-UMTS is a system that has evolved from the existing UMTS system.

The basic standardization of the E-UMTS system is currently being developed by the Third Generation Partnership Project (3GPP). The E-UMTS system can be called a long-term evolution (LTE) system.

As shown in Figure 1, an E-UMTS network can be composed of an E-UTRAN and a core network (CN). E-UTRAN may include user equipment (UE), a base station called eNodeB or eNB, and an access gateway (AG) located at the end of the network and connected to an external network.

AG can be divided into a part for processing user traffic and a part for processing control traffic. The AG part for processing user traffic and the AG part for processing control traffic can be connected to each other via a new interface for communication.

One or more cells can exist in eNodeBs (eNBs), and these eNodeBs can be connected by an interface for transmitting user traffic or controlling traffic.

CN may also include AG and a node for user registration of UE. An interface can also be provided in E-UMTS to distinguish E-UTRAN and CN.

The radio interface protocol layer between a mobile terminal and a network can be divided into a first layer (L11) and a second layer according to the three lower layers of the well-known Open System Interconnection (OSI) model in the communication system. Layer (L2), and a third layer (L3). The physical layer of the first layer uses physical channels to provide information transfer. A radio resource control (RRC) layer located in the third layer controls the radio resources between the mobile terminal and the network.

The RRC layer exchanges RRC messages between the mobile terminal and the network. The RRC layer can be located in each network node such as eNodeB and AG, or located in eNodeB or AG.

Figure 2 shows the architecture of the control plane of the radio interface protocol between a terminal and a UMTS terrestrial radio access network (UTRAN) based on the 3GPP radio access network specifications. The radio interface protocol level in Figure 2 is represented by a physical layer, a data link layer, and a network layer, and the vertical is represented by a user plane for transmitting data and a control plane for transmitting control signals .

The protocol layers in Figure 2 can be divided into a first layer (L1), a second layer (L2), and a third layer according to the three lower layers of the well-known Open System Interconnection (OSI) model in communication systems. Layer (L3). The radio protocol layers in the control plane shown in Figure 2 and the radio protocol layers in the user plane shown in Figure 3 will now be explained.

A physical layer (which is the first layer) uses a physical channel to provide information transfer services to an upper layer. The physical layer is connected to a media access control (MAC) layer located on it via a transmission channel.

Data is transferred between the MAC layer and the physical layer via a transmission channel. Data is also transferred between different physical layers (specifically, between a physical layer on the transmitting side and a physical layer on the receiving side).

The MAC layer of the second layer provides services to the radio link control (PLC) layer (the upper layer) via a logical channel. The RLC layer of the second layer supports reliable data transmission.

It should be noted that the RLC layer is shown in the dashed line, because if the RLC function is implemented in and performed by the MAC layer, the RLC layer itself may not need to exist.

The packet data convergence protocol (PDCP) layer of the second layer is used to use IP packets (such as IPv4 or IPv6) to efficiently transmit data on the radio interface with a relatively narrow bandwidth. The PDCP layer implements header compression to reduce the size of the relatively large IP packet header that contains unnecessary control information.

A radio resource control (RRC) layer at the bottom of the third layer is only defined in the control plane. The RRC layer handles the transmission and physical channels used for the configuration, reconfiguration, and release of radio transmission. A radio transmission (RB) refers to a service provided by the second layer for data transfer between mobile terminals and UTRAN.

The downlink transmission channel used to transmit data from a network to a mobile terminal can include a broadcast channel (BCH) for transmitting system information, and a downlink transmission channel for transmitting user traffic or control messages Shared channel (SCH). User traffic or control messages for downlink multicast services or broadcast services can be transmitted via the downlink SCH, or via an additional downlink multicast channel (MCH). Used to transmit data from a mobile terminal to a network uplink transmission channel, which can include a random access channel (RACH) for transmitting an initial control message, and an uplink for transmitting user traffic or control messages Link shared channel (SCH).

A random access channel (RACH) will be explained in detail below. Generally speaking, when a terminal is synchronized with a network or the terminal transmits corresponding data for the uplink, if there is no uplink radio resource to transmit the data, a RACH is used to obtain a radio resource.

For example, when a terminal is turned on, the terminal will generally synchronize to the downlink, so that it can receive system information from a cell that it needs to access. The terminal should transmit an access request message to the network or base station for an RRC connection after receiving the system information. However, if it is not currently synchronized with the network and has not acquired uplink radio resources, the terminal uses RACH.

In other words, the terminal uses RACH to request a radio resource for transmitting the access request message to the network. The base station then allocates an appropriate radio resource to the terminal to allow the terminal to transmit RRC connection messages. The terminal can then use the allocated radio resources to transmit the RRC connection message to the network.

In another example, when the terminal forms an RRC connection with the network, the terminal obtains radio resources from the network according to the radio resource schedule, and uses the allocated radio resources to transmit data to the network. However, if no data is left in the terminal buffer, the network may not allocate uplink radio resources because it is inefficient to allocate uplink radio resources to a terminal without data transmission. The status of the terminal buffer is reported to the network periodically or according to events. If new data that does not require a radio resource is generated in the buffer, the terminal uses RACH because it currently does not have allocated uplink radio resources. In other words, the terminal uses RACH to request a radio resource that needs to transmit data to the network.

In the following, RACH, one of Wide Frequency Division Code Multiple Access (WCDMA), will be explained. The RACH channel is used to transmit data with a short length through the uplink.

Some RRC messages (such as RRC connection request messages, cell update messages, or URA update messages) can be transmitted on RACH. The logical channels CCCH (shared control channel), DCCH (dedicated control channel) and DTCH (dedicated traffic channel) are mapped to RACH, and RACH is mapped to a physical channel PRACH (physical random access channel).

When the MAC layer of the terminal instructs a PRACH to be transmitted to the physical layer of a terminal, the physical layer of the terminal selects an access slot and a signature to transmit a PRACH preamble to the physical layer of the terminal via the uplink. The preamble is transmitted for an access slot interval of 1.33 milliseconds. One of the sixteen signatures is selected and transmitted up to a certain length of the first initial part of one of the access slots.

After the terminal transmits the preamble, the base station uses the downlink physical channel AICH (acquisition indicator channel) to transmit a response signal. In response to the AICH transmission transmitted by the preamble, the signature selected by the preamble reaches a certain length of the access slot corresponding to the initial part of the transmitted access slot.

The base station uses the signature transmitted from the AICH to transmit a positive response (ACK) or negative response (NACK) to the terminal. When receiving the ACK signal, the terminal uses an OVSF code corresponding to the transmitted signature to transmit a message part with a length of 10 milliseconds or 20 milliseconds. When a NACK is received, the MAC layer of the terminal instructs to transmit PRACH again to the physical layer of the terminal after an appropriate period of time. If the terminal does not receive the AICH corresponding to the previous transmission preamble, the terminal transmits a new preamble after a designated access slot using a power level higher than the previous preamble.

The channel quality indicator (CQI) information system enables a terminal to measure the status of the downlink channel in the current cell and provides information about the measurement status to the base station. The base station then uses the provided CQI information to perform radio resource scheduling. For example, if the value of CQI may be from 1 to 10, then 1 indicates that the channel system is not in a good state, and 10 indicates that the channel system is in a good state.

When the terminal transmits the CQI information of 10 to the base station, the base station can determine that the current downlink channel is in a good state, and transmit the data to the terminal according to a higher bit rate. Conversely, when the terminal transmits 1 CQI information to the base station, the base station can determine that the downlink channel is not in a good state, and transmit the data to the terminal according to a lower bit rate. The base station informs the terminal in advance, that is, the terminal should report to transmit CQI information periodically or according to the occurrence of an event.

Another example of the control signal from the terminal to the base station is hybrid automatic repeat and request (HARQ) ACK/NACK signaling. HARQ refers to the operation obtained by combining ARQ performed by the RLC layer and forward error correction performed by the physical layer.

In other words, if it determines that the data received from the MAC layer and the physical layer is incorrect, the terminal requests to retransmit data from the base station and receive the data again. If the reception is performed successfully, the receiver (terminal) transmits an ACK signal to the transmitter, and if the reception fails, it transmits a NACK signal to the transmitter to notify the status of the data received from the transmitter (base station). The transmitter decides whether to retransmit the corresponding data according to the ACK/NACK signal.

Another example of the control signal from the terminal to the base station is the status report message of the RLC layer. The RLC layer performs ARQ to transmit reliable data. In other words, the transmitter attaches a serial number to each data unit, and the receiver recognizes the serial number of the data unit received from the RLC layer to determine whether all data has been transmitted.

For example, when the transmitter has transmitted the first to tenth data units to the receiver, and the RLC layer of the receiver normally receives eight data units (corresponding to the first to fifth data units and the eighth to tenth data units) At this time, it informs the transmitter that the sixth and seventh data units have not been received correctly and other data units have been received correctly through the status report message. Therefore, the transmitter transmits the sixth and seventh data units to the receiver again after receiving the status report message.

In a related method, if data to be transmitted to the base station, the RRC connected state having no uplink radio resource one of the source terminal uses the RACH, the base station provides to request a radio resource for data transmission. However, if the terminal uses RACH, problems may occur because the terminal request may collide with requests from other terminals. For example, if two or more terminals simultaneously transmit the RACH preamble and the same resource by using the same signature, collisions will occur and the delay time for requesting radio resources will increase.

In addition, a terminal using RACH should wait as much time as the next allocation cycle of RACH resources. For example, if the RACH resource allocation cycle is 10 milliseconds, the terminal should wait up to 10 milliseconds to use RACH.

Furthermore, when one of the terminals in the RRC connection state does not have uplink radio resources that need to transmit data to the base station, and all the terminals use RACH to request radio resources, the allocation of RACH resources will increase accordingly. Under these circumstances, collisions between transmissions from terminals may occur, and the delay time increases as much as the allocation period of RACH resources. In addition, when the amount of RACH resources increases because all terminals request radio sources through RACH, problems may also occur.

An object of the present invention is to provide a method of using an uplink and a control signal for RACH to quickly obtain a radio resource from a base station.

In one aspect of the present invention, a method for scheduling radio resources in a mobile communication system is provided. The method includes transmitting a control signal including an instruction to request radio resources; receiving a first allocated radio resource; and using the first allocated radio resource to transmit a message.

The present invention covers: if the amount of data left to be transmitted is more than the amount of data that can be transmitted using the first allocated radio resource, the message includes a request for a second radio resource, or if the data to be transmitted is left If the amount is less than or equal to the amount of data that can be transmitted using the first allocated radio resource, the message only includes data. The present invention further covers that the message is a request for a second radio resource, and the method further includes receiving a second allocated radio resource, and using the second allocated radio resource to transmit data.

The present invention also covers the request for the radio resource including information. Further covering the control signal, it includes one of the following: CQI information, an ACK/NACK, or a status report message.

In another aspect of the present invention, a method for scheduling radio resources in a mobile telecommunication system is provided. The method includes transmitting an instruction including requesting a radio resource, the instruction being included in one of a preamble transmitted through a random access channel (RACH) and a control signal transmitted through a control channel; receiving; A first allocated radio resource; use the first allocated radio resource to transmit a request for a second radio resource, the request including data; receive a second allocated radio resource and use the second allocated radio resource to transmit data.

The present invention covers the transmission of an indication requesting a radio resource, which includes calculating a first time required to use RACH to obtain radio resources, and a second time required to obtain radio resources using control signals, and determining the calculated first time Which of the first time and the second time is less. The present invention further covers the instruction of requesting a radio resource for transmission, which includes determining a data service type, and if the data service type is sensitive to delay time, including the instruction for requesting a radio resource in the preamble; Or if the data service type is not sensitive to the delay time, then the instruction to request a radio resource is included in the control signal. Preferably, the transmission request for an indication of a radio resource includes determining a priority order of data services, calculating a first time required to obtain radio resources using RACH, and a second time required to obtain radio resources using control signals. Time, and if it is determined that the data service has a high priority, based on which of the calculated first time and second time is less, the instruction is included in one of the preamble and control signal, or if It is determined that the data service has a low priority, and the instruction is included in the control signal.

In one aspect of the present invention, a method for scheduling radio resources in a mobile telecommunication system is provided. The method includes receiving a control signal (which includes requesting an indication of a radio resource), transmitting a first allocated radio resource, and receiving a message transmitted using the first allocated radio resource.

The present invention covers: if the amount of data to be transmitted is left in a mobile terminal that transmits the message, which is more than the amount of data that can be transmitted using the first allocated radio resource, then the message includes a message for a second radio resource. Request; or if the amount of data left to be transmitted in the mobile terminal is less than or equal to the amount of data that can be transmitted using the first allocated radio resource, the message only includes data. The present invention further covers that the message is a request for a second radio resource, and the method further includes transmitting a second allocated radio resource and receiving data transmitted using the second allocated radio resource.

The present invention covers this request for radio resources, including data. The present invention further includes the method of determining whether the data is reserved for transmission by a mobile terminal receiving the message. Preferably, the control signal includes one of the following: CQI information, an ACK/NACK, and a status report message.

In another aspect of the present invention, a method for scheduling radio resources in a mobile telecommunication system is provided. The method includes receiving an instruction including requesting a radio resource, the instruction being included in one of a preamble transmitted through a random access channel (RACH) and a control signal transmitted through a control channel; transmitting; A first allocated radio resource; receiving a request for a second radio resource using the first allocated radio resource; the request includes data; transmitting a second allocated radio resource, and receiving a transmission using the second allocated radio resource material.

The present invention covers: if the time required for a mobile communication terminal to use RACH to transmit the instruction to obtain radio resources is less than the time required for the mobile communication terminal to use control signals to obtain radio resources, then request a radio resource The instruction is received in the preamble; or if the time required for the mobile communication terminal to use RACH to obtain radio resources is more than the time required for the mobile communication terminal to use the control signal to obtain radio resources, Then the instruction is received in the control signal. The present invention further covers that if a data service type is sensitive to delay time, the instruction to request a radio resource is received in the preamble, or if the data service type is not sensitive to delay time, the instruction is in the control The signal is received. Preferably, if a data service has a high priority, and the time required for a mobile communication terminal to use RACH to transmit the instruction to obtain radio resources is less than the time required for the mobile communication terminal to use control signals to obtain radio resources At a time when the request for a radio resource is received in the preamble; or if the data service has a low priority, or if the data service has a high priority and the mobile communication terminal uses RACH to obtain The time required for the radio resource is more than the time required for the mobile communication terminal to use the control signal to obtain the radio resource, and the instruction is received in the control signal.

The following description will propose additional features and advantages of the present invention, and part of them will be understood from the description, or can be learned by the implementation of the present invention. It should be understood that the above general description and the following detailed description of the present invention are exemplary and explanatory, and are intended to provide further explanations of the patent application scope of the present invention.

Those skilled in the art will also be able to understand these and other exemplary embodiments from the following detailed description of the specific embodiments with reference to the accompanying drawings, and this text is not limited to any specific embodiments disclosed.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Although the present invention will be described in conjunction with preferred specific embodiments, it should be understood that the specific embodiments described are not intended to specifically limit the present invention to these specific embodiments. On the contrary, the present invention is intended to cover alternatives, modifications and equivalents, which may be included in the spirit of the present invention as defined by the scope of the appended application.

The disclosure of the present invention relates to mobile telecommunication systems (such as E-UMTS). However, the present invention can be applied to telecommunication systems operating in accordance with other standards.

The present invention provides a method for allowing a terminal to use an uplink and use one of RACH control signals to request a radio resource when the terminal is in an RRC connection state and does not have uplink radio resources. Preferably, the control signal includes one of CQI information indicating the channel status of the downlink, ACK/NACK signaling of HARQ, and status report information of the RLC layer. Preferably, the terminal transmits a radio resource allocation request message to the base station (eNode-B), and the base station performs radio resource scheduling.

Figure 4 shows a method for requesting a radio resource in a mobile telecommunications system according to an embodiment of the present invention. As shown in Figure 4, even if the terminal 10 (UE) receives downlink data from the base station (eNode-B) 20 (S10), the terminal currently has no uplink data to transmit to the base station, and has not received the downlink data from the base station. Allocate any uplink radio resources.

Although the terminal 10 does not have data to be transmitted to the uplink, it should transmit control information (such as CQI information, HARQ ACK/NACK signaling, and status report messages) to the base station 20. The CQI information reports the radio channel status of the downlink and the status report message indicates the data unit received in the RLC layer.

In other words, the terminal 10 should transmit the control signal to the base station 20 while receiving data from the base station, even if the terminal does not have the data to be transmitted to the base station. Therefore, the base station 20 allocates a specific radio resource to the terminal 10 to allow the terminal 10 to transmit control signals.

When the new data to be transmitted is in the buffer, the terminal 10 still does not have allocated uplink radio resources (S11). This is because the buffer was previously empty. Therefore, the terminal must request a radio resource from the base station 20 to transmit new data.

The terminal 10 can use control signals (such as CQI information, HARQ ACK/NACK signaling, and a status report of the RLC layer) to request radio resources from the base station 20. In other words, the terminal 20 can notify the base station 20 of the request for radio resources through the control signal (S12).

One method of the present invention adds 1 bit of information to the control signal, and uses the control signal to request radio resources from the base station 20. The 1-bit information indicates whether the terminal 10 requests the radio resource.

Another method of the present invention for using control signals to request radio resources from the base station 20 is to use existing information bits. For example, if CQI transmission is 4-bit information, and bits between 0000 and 1100 are used to represent CQI information, "1111" can be used as information to request the radio resource.

The base station 20 determines whether the terminal 10 requests radio resources through the radio resource request information included in the control signal. When the terminal 10 requests radio resources, the base station 20 allocates the radio resources to the terminal so that the terminal can transmit a radio resource request message (S13).

When the uplink radio resource is allocated from the base station, the terminal 10 transmits a radio resource request message to the base station 20 (S14). The radio resource request message may include the buffer status of the terminal, the priority of the terminal, the priority of the data, and CQI information.

Depending on the rate of the radio resource allocated from the base station 20, the radio resource request message may additionally include the terminal's data. For example, if the terminal 10 can send 100 bits to the allocated radio resource for transmitting a radio resource request message from the base station 20, and the radio resource request message has a size of 20 bits, if the terminal 10 has 200 bits If the size of the buffer is larger, the terminal 10 transmits 80 bits of data together with the radio resource request message through the allocated radio resources.

In addition, if the buffer has small-scale data, the terminal 10 can transmit the data of the terminal without a radio resource request message. For example, if the base station 20 can send 100 bits of data to the allocated radio resource for transmitting the radio resource request message from the base station 20, the buffer has 90 bits of data and the radio resource request message is 20 bits Therefore, the terminal 10 only includes the 90-bit data of the buffer in the 100-bit radio resource, and there is no radio resource request message. If the radio resource request message is not included in the radio resources allocated for transmitting the radio resource request message, the base station 20 determines that the data used for transmission no longer exists in the terminal.

After receiving the radio resource request message, the base station 20 allocates radio resources to the terminal 10 (S15). As mentioned above, if all the data of the terminal has been transmitted to the base station along with the radio resource request message, or all the data has been transmitted to the corresponding radio resource, the base station 20 no longer allocates radio resources to the terminal 10. In other words, the base station 20 can determine whether all the data of the terminal 10 has been transmitted through the information of the radio resource request message or the appearance of the message.

Once the terminal 10 allocates radio resources from the base station 20, it transmits uplink data to the base station through the radio resources (S16).

According to the present invention, a terminal without radio resources can request radio resources to transmit new data by using control signals or RACH.

In a first method of the present invention, the terminal decides whether to use RACH or control signal according to a time for acquiring radio resources. In other words, the terminal compares the sum of the RACH resource period and the time required to use RACH to obtain radio resources with the sum of the RACH resource period and the time required to use control signals to obtain radio resources, and decides whether to use RACH or control Signal.

For example, consider the RACH resource period system T_RACH, The terminal is concerned with the standby time of the next RACH resource period in which the radio resource is requested from the buffer as new data is T_RACH-NOW, And the time to obtain radio resources for data transmission by using RACH is T_{RACH_ALLOCATED RESOURCE}. The sum of the time required to obtain radio resources from the terminal as new data by using RACH is T_RACH-NOw+T_{RACH_ALLOCATED RESOURCE}。

In addition, consider the backup time T for the terminal to send the next control signal to request radio resources from the terminals buffer as new data._{NEXT CONTROL}, And the time for obtaining radio resources for data transmission by using the control signal is T_{CONTROL_ALLOCATED RESOURCE}. The total time required to allow the terminal to obtain radio resources by using the control signal is T_{NEXT CONTROL}+T_{CONTROL_ALLOCATED RESOURCE}。

Therefore, the terminal compares T_RACH-NOW+T_{RACH_ALLOCATED RESOURCE}With T_{NEXT CONTROL}+T_{CONTROL_ALLOCATED RESOURCE}And use a method with less delay time.

For example, when new data occurs but no radio resources are available, if it takes 20 milliseconds to obtain radio resources using RACH, and it takes 10 milliseconds to obtain radio resources using control signals, the terminal uses the control signal to request radio resources from the base station . Conversely, when new data occurs but no radio resources are available, if it takes 20 milliseconds to obtain radio resources using RACH, and 30 milliseconds to obtain radio resources using control signals, the terminal uses RACH to request radio resources from the base station.

In the second method of the present invention, the terminal decides whether to use RACH or control signal according to a data service type. In other words, the terminal uses the control signal for data services that are less sensitive to delay time, and uses RACH for data services that are more sensitive to delay time.

For example, for a data service with relatively insensitive delay time (such as Internet service), even if it takes 15 milliseconds to use RACH and 20 milliseconds to use the control signal, the terminal will still use the control signal. When it needs to consider the efficiency of radio resources, RACH resources can be allocated in a relatively small range because the terminal requests radio resources by using RACH and control signals separately. On the contrary, the terminal uses RACH for traffic services that are sensitive to delay time.

In the third method of the present invention, the terminal decides whether to use RACH or control signal according to the priority of the data. In other words, the terminal uses RACH for high-priority services, and uses control signals for low-priority services.

The terminal also calculates the total time of using the RACH or control signal to obtain radio resources, and selectively uses the RACH or control signal for a service with high priority based on the less total time. The terminal always uses the control signal for a service with low priority.

According to the present invention, fast data transmission of each terminal can be ensured, because the terminal can quickly and effectively transmit the radio resource request message to the base station, and can quickly obtain radio resources from the base station.

Since the present invention can be embodied in several forms without departing from its spirit or basic characteristics, it should also be understood that unless otherwise specified, the above specific embodiments are not limited to any details previously described, but should be broadly regarded as accompanying Attached within the scope of the definition of the scope of patent application. Therefore, all changes and modifications that fall within the measurement and limits of the scope of the patent application, or the equivalent of these measurements and limits, are expected to be covered by the scope of the patent application.

The foregoing specific embodiments and advantages are merely exemplary and should not be construed as limiting the present invention. This teaching can be easily applied to other types of equipment.

The description of the present invention is intended to demonstrate and does not limit the scope of the patent application. Those who are familiar with this technology will understand many alternatives, modifications and changes. In the scope of the patent application, when the quotation function is implemented, the component-plus-function clause is intended to cover the structure described here, and is not only structurally equivalent but also an equivalent structure.

<p>10. . . terminal</p><p>20. . . Base station</p>

The accompanying drawings included herein provide a further understanding of the present invention, and are incorporated into and constitute a part of this specification. The accompanying drawings show specific embodiments of the present invention and together with descriptions are used to explain the principle of the present invention. The features, elements, and aspects of the present invention referenced by the same numbers in different figures indicate the same, equivalent or similar features, elements, or aspects according to one or more specific embodiments.

Figure 1 shows the E-UMTS network structure of a mobile communication system, which can be applied to both related technologies and the present invention.

Figure 2 shows the various layers of the control plane of the radio protocol.

Figure 3 shows the various layers of the user plane of the radio protocol.

Figure 4 shows a method for requesting a radio resource in a mobile telecommunications system according to an embodiment of the present invention.