Patent Description:
With the rapid advance of communication technology, mobile communication systems have evolved to a 4th Generation (<NUM>) communication systems represented by Long Term Evolution (LTE) standardized 3rd Generation Partnership Project (3GPP). The LTE system adopts technologies for supporting various types of User Equipment (UE) including Machine Type Communication (MTC) UE. The MTC UE may be a device, such as an electricity meter and water meter, which is capable of metering consumption of a utility item and reporting the data result automatically and is characterized by low network access priority.

Typically, such an MTC UE configured for the purpose of metering does not need a high data transmission capability and is likely to have low transmit power and be installed in a place such as such as basement and warehouse. There is therefore a need of assorting a UE category requiring coverage expansion function to overcome the low transmit power while operating at a low data rate. For this purpose, new UE category <NUM> is added in addition to the legacy UE categories in LTE release <NUM> (the larger the release number, the more recent the version is). The category <NUM> UE is characterized by the low data rate (e.g., <NUM> Megabit(s) per second (Mbps)) and may adopt supplementary transmission schemes to secure relatively broad coverage at the low transmit power level. The supplementary transmission schemes may include repetitive transmission scheme.

In order for the network support the supplementary transmission scheme of the UE, the UE has to connect to the evolved Node B (eNB) supporting the corresponding transmission scheme. Also, the UE has to notify the network that the UE is the MTC UE as soon as possible after being connected to the eNB such that the network is capable of recognizing the connection of the MTC UE and applying the supplementary transmission scheme to the MTC UE immediately to maintain a connection stably.

Aspects of the present disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide an evolved Node B (eNB)/cell (re)selection method of a Machine Type Communication (MTC) User Equipment (UE) that is capable of allowing the MTC UE to connect the eNB supporting the eNB's UE class with priority and notifying the network of the eNB's MTC UE class as soon as possible.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein may be made without departing from the scope of the present disclosure.

The present disclosure proposes the following methods in order for a Machine Type Communication (MTC) User Equipment (UE) to select an evolved Node B (eNB) supporting MTC UE.

The eNB transmits the eNB's MTC UE supportability using a broadcast message.

The broadcast message may be a determined System Information Block (SIB).

The UE scans eNBs per frequency and, if the eNB or cell having the strongest signal on one frequency does not support MTC UE, bars the access on the frequency and reduces the priority of the corresponding frequency in a determined duration. That is, although a cell having strong signal strength is found while scanning the corresponding frequency supporting the UE for selection, the UE selects, if there is any cell found on another frequency, the cell operating on the another frequency.

Also, the present disclosure proposes the following methods in order for the MTC UE to notify the eNB that the MTC UE is a UE of a MTC UE type when the MTC UE attempts to connect the eNB.

The header of a message transmitted from the UE to the eNB in the random access procedure includes a logical channel identifier (LCID) for use at the eNB in determining whether the UE is an MTC UE.

The message transmitted from the UE to the eNB may be message <NUM> (Msg3) among the messages used in the random access procedure.

Upon receipt of the message including the LCID, the eNB determines the corresponding UE as an MTC UE and then applies, to the communication with the corresponding UE, transmission message size adjustment (e.g., fragmentation) and supplementary transmission scheme (e.g., retransmission).

<FIG> is a diagram illustrating an architecture of a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

Referring to <FIG>, a radio access network of the LTE system includes eNBs <NUM>, <NUM>, <NUM>, and <NUM>, a Mobility Management Entity (MME) <NUM>, and a Serving-Gateway (S-GW) <NUM>. A UE <NUM> connects to an external network via the eNBs <NUM>, <NUM>, <NUM>, and <NUM> and the S-GW <NUM>.

Referring to <FIG>, the eNBs <NUM>, <NUM>, <NUM>, and <NUM> correspond to the legacy node Bs of the Universal Mobile Telecommunications System (UMTS). The eNBs <NUM>, <NUM>, <NUM>, and <NUM> allow the UE <NUM> to establish a radio channel and are responsible for functions more complicated as compared to the legacy node B. In the LTE system, all the user traffic services including real time services such as Voice over Internet Protocol (VoIP) are provided through a shared channel and thus there is a need of a device to schedule data based on the state information such as buffer states, power headroom states, and channel states of the UEs, the eNBs being responsible for such functions. Typically, one eNB controls a plurality of cells. In order to secure the data rate of up to 100Mbps, the LTE system adopts Orthogonal Frequency Division Multiplexing (OFDM) as a radio access technology. Also, the LTE system adopts Adaptive Modulation and Coding (AMC) to determine the modulation scheme and channel coding rate in adaptation to the channel condition of the UE. The S-GW <NUM> is an entity to provide data bearers so as to establish and release data bearers under the control of the MME <NUM>. The MME <NUM> is responsible for mobility management of UEs and various control functions and may be connected to a plurality of eNBs.

<FIG> is a diagram illustrating a protocol stack of an LTE system according to an embodiment of the present disclosure.

Referring to <FIG>, a protocol stack of the LTE system includes Packet Data Convergence Protocol (PDCP) <NUM> and <NUM>, Radio Link Control (RLC) <NUM> and <NUM>, Medium Access Control (MAC) <NUM> and <NUM>, and Physical (PHY) <NUM> and <NUM>. The PDCPs <NUM> and <NUM> are responsible for IP header compression/decompression, and the RLCs <NUM> and <NUM> are responsible for segmenting the PDCP Protocol Data Unit (PDU) into segments in appropriate size for Automatic Repeat Request (ARQ) operation. The MACs <NUM> and <NUM> are responsible for establishing connection to a plurality of RLC entities so as to multiplex the RLC PDUs into MAC PDUs and demultiplex the MAC PDUs into RLC PDUs. The PHYs <NUM> and <NUM> performs channel coding on the MAC PDU and modulates the MAC PDU into OFDM symbols to transmit over radio channel or performs demodulating and channel-decoding on the received OFDM symbols and delivers the decoded data to the upper layer. Also, the PHY layer uses Hybrid ARQ (HARQ) for additional error correction by transmitting <NUM> bit information indicating for positive or negative acknowledgement from the receiver to the transmitter. This is referred to as HARQ ACK/NACK information. The downlink HARQ ACK/NACK corresponding to the uplink transmission is carried by Physical Hybrid-ARQ Indicator Channel (PHICH), and the uplink HARQ ACK/NACK corresponding to downlink transmission is carried by Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH).

<FIG> is a signal flow diagram illustrating a cell selection method of an MTC UE according to an embodiment of the present disclosure.

Referring to <FIG>, a UE <NUM> powers on at operation <NUM> and initiates a cell selection procedure to select a cell to camp on among the neighboring eNBs (or cells) <NUM> and <NUM> at operation <NUM>.

For this purpose, the UE scans operating cells (frequencies) the UE supports to discover cells. Herein, the terms "frequency" and "cell" are used interchangeably in the same meaning. In <FIG>, the UE scans frequency <NUM> (f1) first at operation <NUM>. After switching to the corresponding frequency to scan the frequency <NUM>, the UE <NUM> receives the signals transmitted on the frequency <NUM>. From the received signals, the UE <NUM> may extract synchronization signals <NUM> and messages <NUM> carrying system information. The message carrying the system information includes a plurality of SIBs that are sorted into SIB1, SIB2, SIB3, etc. according to the purpose and type of information.

The UE <NUM> selects an eNB <NUM> or <NUM> with the best received signal strength among eNBs <NUM> and <NUM> transmitting the synchronization signal to acquire synchronization with the corresponding eNB at operation <NUM> and receives messages (e.g., SIBs) from the eNB synchronized therewith at operation <NUM>. According to an embodiment of the present disclosure, if the eNB <NUM> or <NUM> is supports the MTC UE (allows an access of the MTC UE to a cell formed by the eNB <NUM> or <NUM>), the eNB <NUM> or <NUM> sends the MTC UE an indicator of notifying the UE <NUM> whether the eNB <NUM> or <NUM> supports the MTC UE. The indicator may be <NUM>-bit indicator transmitted through one of the SIBs (e.g., SIB1 or an SIB defined newly). The indicator may be allowance information regarding an access of the category <NUM> UE to the cell formed by the eNB <NUM> or <NUM>.

The UE <NUM> establishes synchronization with the eNB <NUM> or <NUM> having the best signal strength and quality per frequency to determine the cell to camp on and monitors the SIBs to detect the indicator indicating of the MTC UE supportability through the neighboring cell scanning. If the corresponding eNB <NUM> or <NUM> does not support the MTC UE, the UE <NUM> blocks scanning the corresponding frequency (bars to camp on the eNB) during a determined period at operation <NUM>. That means that the eNB <NUM> or <NUM> bars a selection of a cell if the eNB <NUM> or <NUM> does not allows an access of MTC UE to the cell formed by the eNB <NUM> or <NUM>. This is to prevent the MTC UE from staying in the coverage of the eNB <NUM> or <NUM>, which does not support the MTC UE so as to avoid communication failure afterward. In order to accomplish this, a timer or counter may be used, and the length of the timer or the value of the counter may be set to a value predefined in the standard or carried in the SIB message transmitted by the eNB <NUM> or <NUM> supporting MTC. For example, the eNB <NUM> or <NUM> may broadcast the timer value for barring to camp on (e.g., <NUM> minute) in the SIB <NUM> in order for the UEs located within the cell to receive the timer value. If the timer value is received, the MTC UE starts the timer when the cell having the best signal strength on a specific frequency does not support MTC to reduce the cell selection priority of the corresponding frequency during the time corresponding to the timer (<NUM> minute in this embodiment of the present disclosure). The timer or counter may start when it is determined that the corresponding eNB <NUM> or <NUM> does not support MTC for the reason of reception failure of the MTC indicator. The UE <NUM> may bar the frequencies on which the cells supporting MTC operate after the completion of cell search or upon or after determining the frequency or cell to camp on.

After finding the eNB <NUM> or <NUM> having the best signal strength on the frequency <NUM>, the UE <NUM> switches the frequency to the frequency <NUM> (f2) to search for the eNB <NUM> or <NUM> having the best signal strength on the f2 at operation <NUM>.

Like the operation on the f1, the UE <NUM> selects the eNB <NUM> or <NUM> having the best signal strength among the eNBs <NUM> and <NUM> operating on the ff2 to establish synchronization with the corresponding eNB at operation <NUM> and receives the messages (e.g. SIBs) transmitted by the corresponding eNB <NUM> or <NUM> at operation <NUM>. It is assumed the eNB <NUM> or <NUM> with which the synchronization is acquired on the ff2 is the eNB <NUM> or <NUM> supporting MTC. As described above, the eNB <NUM> or <NUM> with which the synchronization is acquire on the ff2 may transmit the system information block including the indicator notifying whether the eNB <NUM> or <NUM> supports MTC. Although <FIG> is directed to the case where the UE <NUM> performs the procedure of receiving from the eNBs <NUM> and <NUM> operating on two frequencies (f1 and f2), the present disclosure is not limited thereto. For example, the UE may perform the above procedure on <NUM> (f1 to f15) frequencies.

The UE <NUM> checks information on the cells having the best signal strength on the respective frequencies, checks the MTC supportabilities of the cells, and determines the cell to camp thereon based on the operator information and MTC cell supportabilities of the per-frequency cells at operation <NUM>. As described above, if the non-MTC cells are barred, the UE <NUM> may bar scanning the corresponding frequencies since the eNB <NUM> or <NUM> is determined as non-MTC eNB at operation <NUM>, the barring state may last until operation <NUM>. Unlike this, the UE <NUM> may bar the frequencies on which the cells supporting MTC operate after the completion of cell scanning or upon or after determining the frequency or cell to camp on.

Referring to <FIG>, a UE <NUM> powers on at operation <NUM> and starts the cell selection procedure to select one of the cell among the neighboring cells (or eNBs) <NUM> and <NUM> at operation <NUM>.

Since operations <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> of <FIG> are identical with operations <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> of <FIG>, detailed descriptions thereof are omitted herein. Although <FIG> is directed to the case where two frequencies are scanned, the present disclosure is not limited thereto.

Referring to <FIG>, if it is determined that the corresponding eNB <NUM> or <NUM> does not support MTC based on the message received from the eNB, e.g. since it is determined that the corresponding eNB <NUM> or <NUM> does not support the MTC UE, the corresponding frequency is barred during a determined period. Unlike the embodiment of <FIG>, the frequencies on which the non-MTC cells operate are barred after the completion of the cell search or upon the determination of the frequency or cell to camp on or after a determined time lapses since the determination of the frequency or cell to camp on at operation <NUM>. <FIG> is directed to the case whether the f1 is barred during a determined period. Assuming that the UE <NUM> supports <NUM> frequencies (f1 to f15) unlike the embodiment of <FIG>, the frequencies on which non-MTC cells operate (e.g. f1, f5, and f11) may be barred after the completion of the cell search on all of the <NUM> frequencies.

<FIG> is a flowchart illustrating a cell selection method of an MTC UE according to an embodiment of the present disclosure.

Referring to <FIG>, if the cell selection procedure starts, the UE determines whether the previous cell selection-related information is stored at operation <NUM>. For example, if the UE has powered on and then off, the information used in the last connection may be stored in the UE's storage. If there is such information stored in the UE, the UE selects the frequencies based on the corresponding information and searches for per-frequency best cells and receives information from the found cells at operation <NUM>. Otherwise if there is no such information stored in the UE, the UE searches all frequencies for per-frequency best cells and receives information from the found cells at operation <NUM>. Afterward, the UE selects the frequencies having non-MTC cells among the per-frequency best cells at operation <NUM>. In this way, the UE may determine whether there is any non-MTC frequency depending on whether the eNB transmits the MTC indicator at operation <NUM> as described with reference to <FIG>. If there are one or more non-MTC frequencies, the corresponding frequency (or frequencies) is barred during a determined period such that the UE rules out the corresponding frequency (or frequencies) in the cell selection procedure at operation <NUM>. In order to check the expiry of the determined period, a timer or counter may be used.

Afterward, the UE selects a cell to camp on among the per-frequency cells based on the operator information and MTC UE supportability at operation <NUM> and ends the cell selection procedure at operation <NUM>.

<FIG> is a flowchart illustrating an eNB-side procedure of a cell selection method according to an embodiment of the present disclosure.

Referring to <FIG>, an eNB determines whether the eNB supports MTC UE at operation <NUM>. If the eNB supports the MTC UE, the eNB generates a system information block message including an MTC supportability indication information at operation <NUM>. The MTC supportability indication information may include a <NUM>-bit indicator indicating whether the eNB supports the MTC UE and information on the frequency barring time or counter value optionally. If the eNB does not support MTC UE, the eNB generates the system information block message without MTC support indication information at operation <NUM>. Next, the eNB transmits the generated system information block to the UE at operation <NUM>.

<FIG> is a signal flow diagram illustrating a random access procedure of an MTC UE to an eNB supporting the MTC UE according to an embodiment of the present disclosure.

Referring to <FIG>, it is assumed that a UE <NUM> is an MTC UE (category <NUM> UE) and the eNB or cell <NUM> supports MTC.

Since the MTC UE operates with a low transmit power and a broad coverage and may transmit small size messages during a determined period, there is a need of an MTC eNB to support the MTC UE. Meanwhile, the MTC eNB has to support normal UEs as well as MTC UEs and distinguish between the normal and MTC UEs based on the category information transmitted by the MTC UE. Category <NUM> is defined newly for the MTC UE and, if the corresponding category information is received, the eNB determines the corresponding UE as MTC UE and adopts a specific transmission scheme for the MTC UE (which is different from that for normal UE) in order for the MTC UE to transmit small size message at a low transmit power.

According to the method of the related art, the category information is transmitted after the UE connects to the corresponding eNB successfully so as to be in the connected mode. That is, if data communication necessity occurs in the idle mode, the UE initiates a random access procedure to enter the connected mode and, when the random access procedure is completed successfully, then it is possible for the UE to transmit the category information. Accordingly, the UE cannot identify whether the corresponding UE is a normal UE or an MTC UE in the middle of the random access procedure and thus there is a need of negating the necessity for transmitting the random access message in a specific way (e.g. repetitive transmission) or segmenting a large message into small size messages. The embodiment of <FIG> shows a procedure of solving such a problem.

If data communication necessity occurs in the idle mode, the UE <NUM> transmits a preamble (msg <NUM>) to an eNB <NUM> to enter the connected mode at operation <NUM>. The preamble may be the random access preamble which is transmitted repeatedly by a normal UE or a preamble designed newly for supporting MTC UEs with wide coverage.

Upon receipt of the preamble, the eNB <NUM> sends the UE <NUM> a RAR message (Msg2) to acknowledge the receipt of the preamble at operation <NUM>. The RAR message includes preamble identity information and resource allocation information in order for the UE <NUM>, which has transmitted the preamble to transmit additional message.

If the RAR message is received successfully, the UE <NUM> sends the eNB <NUM> a Connection Setup Request message (Msg3) <NUM>. The connection Setup Request message is the Radio Resource Control (RRC) layer message such as RRCConnectionRequest message specified in the 3rd Generation Partnership Project (3GPP) standard. The UE <NUM> transmits the message on the resource allocated by the eNB <NUM>. The message is transmitted in the MAC Service Data Unit (SDU) of which MAC header includes a <NUM>-bit LCID allocated by the eNB <NUM>. In the case of initial transmission, the UE <NUM> has no LCID allocated by the eNB <NUM> yet and thus, if the UE <NUM> is the normal UE, the UE <NUM> transmits the message using the identifier set to <NUM>. Table <NUM> shows LCID values for use in uplink. Before transitioning from the idle mode to the connected mode after completing the random access procedure successfully, the UE <NUM> uses the identifier set to <NUM> allocated for the Common Control Channel for transmitting control message as shown in Table <NUM>.

However, the present disclosure proposes a method of using a separate value instead of using the LCID <NUM> when the UE <NUM> is an MTC UE. The separate value may be one of the binary values in the range from <NUM> to <NUM> that are reserved currently. According to an embodiment of the present disclosure, the eNB <NUM> checks the LCID included in the message (Msg3) received at operation <NUM> to determine whether the corresponding UE <NUM> is a normal UE or an MTC UE. In this way, the eNB <NUM> may acquire the UE <NUM> information before the end of the random access procedure to allocate resource to the corresponding UE <NUM> and communicate data with the corresponding UE <NUM>. In the case that the UE <NUM> is the MTC UE, the number of bits which the UE <NUM> may receive in one subframe (<NUM> millisecond) is limited (e.g. <NUM> bits). If, although the size of the message (Msg4) to be transmitted at operation <NUM> in response to the Msg3 is longer than <NUM> bits, the eNB <NUM> transmits the data of which size is greater than <NUM> bits, the UE <NUM> cannot receive the Msg4 correctly.

According to an embodiment of the present disclosure, if it is determined that the UE <NUM> is the MTC UE based on the LCID of the UE <NUM> at operation <NUM>, the eNB <NUM> determines whether the size of the message (Msg4 in <FIG>) to be transmitted is greater than the size allowed for the MTC UE at operation <NUM>. If the size of the corresponding message is greater than the message size allowed for MTC UE, the eNB <NUM> may fragment the message or removes part of the message content for transmission at operation <NUM>. The message may be the RRCConnectionSetup message. In this way, the UE <NUM> notifies the network that the UE <NUM> is the MTC UE before the UE <NUM> notifies the network of the UE <NUM>'s MTC capability so as to establish a connection with the eNB <NUM> successfully.

<FIG> is a flowchart illustrating a UE-side procedure of a random access procedure to an eNB supporting MTC UE according to an embodiment of the present disclosure.

Referring to <FIG>, in the random access procedure, the UE transmits a random access preamble to an eNB at operation <NUM>. Afterwards, the UE receives a RAR message in response to the random access preamble at operation <NUM>. As shown in <FIG> or <FIG>, the eNB determines whether the eNB supports MTC based on the MTC supportability indicator at operation <NUM>. If the eNB does not support the MTC UE, the eNB transmits a message having a MAC header including a legacy LCID value at operation <NUM>. If the eNB supports the MTC UE, the eNB transmits a message having the MAC header including a new LCID proposed in the present disclosure at operation <NUM>. Afterward, UE receives a message processed suitable for MTC UE (e.g. fragmented or repeated message) from the eNB at operation <NUM> and ends the random access procedure at operation <NUM>.

<FIG> is a flowchart illustrating an eNB-side procedure of a random access procedure to the eNB supporting MTC UE according to an embodiment of the present disclosure.

Referring to <FIG>, if a message is received on the allocated resource, an eNB determines whether the received message has a MAC header including an LCID proposed newly in the present disclosure at operation <NUM> and, if the received message includes the newly proposed LCID, the eNB determines the corresponding UE as the MTC UE at operation <NUM> and determines whether the size of the message (Msg4 in <FIG>) to be transmitted is greater than the message size allowed for MTC UE. If the size of the message is greater than the message allowed for MTC UE, the eNB fragment the corresponding message or removes part of the message content for transmission at operation <NUM>. In this way, the UE notifies the network of the UE category in advance before transmitting the UE category information so as to establish a connection with the eNB successfully.

<FIG> is block diagram illustrating a configuration of the UE according to an embodiment of the present disclosure.

Referring to <FIG>, a UE according to an embodiment of the present disclosure includes a transceiver <NUM>, a controller <NUM>, a multiplexer/demultiplexer <NUM>, a control message processor <NUM>, and upper layer processor <NUM> and <NUM>.

The transceiver <NUM> is responsible for receiving data and a determined control signal through a downlink channel of the serving cell and transmitting data and determined control signals through an uplink channel. In the case that a plurality of serving cells is configured, the transceiver <NUM> transmits and receives data and control signals through the plural serving cells.

The multiplexer/demultiplexer <NUM> is responsible for multiplexing data generated by the upper layer processors <NUM> and <NUM> and the control message processor <NUM> or demultiplexing data received by the transceiver <NUM> to deliver the demultiplexed data to the upper layer processors <NUM> and <NUM> and the control message processor <NUM>.

The control message processor <NUM> processes the control message received from the eNB and takes a necessary action.

The upper layer processor <NUM> and <NUM> is established per service. The upper layer processors <NUM> and <NUM> process the data generated in the user service such as File Transfer Protocol (FPT) and VolP and transfers the processed data to the multiplexer/demultiplexer <NUM> or processes the data from the multiplexer/demultiplexer <NUM> and delivers the processed data to the upper layer service applications.

The controller <NUM> checks the scheduling command, e.g. uplink grants, received through the transceiver <NUM> and controls the transceiver <NUM> and the multiplexer/demultiplexer <NUM> to perform uplink transmission with appropriate transmission resource at an appropriate timing.

The control message processor <NUM> controls such that the Msg3 message including the newly proposed LCID value is transmitted in the random access procedure when the UE is the MTC UE and thus the eNB is aware of the UE category before receiving the MTC UE notification message as an upper layer message.

Although the transceiver <NUM>, the controller <NUM>, the multiplexer/demultiplexer <NUM>, the control message processor <NUM>, and the upper layer processor <NUM> and <NUM> are depicted as separate blocks responsible for different functions in <FIG> for explanation convenience, the configuration is not limited thereto. For example, if a message is received from the eNB, the controller <NUM> determines whether the message includes an MTC UE supportability indicator and, if no MTC UE supportability indicator is included, the UE bars the frequencies of the corresponding eNB for cell search during a determined period. This message may be a broadcast message. The broadcast message may be a SIB. The controller <NUM> may bar the corresponding frequency right after it is determined that the message has no MTC UE supportability indicator. The controller also may bar the corresponding frequency after the completion of cell search or upon or after a determined time since the determination of the frequency or cell to camp on. If the cell search has been completed on all the frequencies supported by the UE, the controller <NUM> may select the cell to camp on based on the operator information or MTC UE supportability.

If the RAR message is received from the eNB, the controller <NUM> controls to transmit ta connection setup request message to the eNB and receive a connection setup message from the eNB in response to the RAR message. The connection setup request message may include an indicator notifying that the UE is the MTC UE. The connection setup request message may be the RRCConnectionRequest message. The indicator informing that the UE is the MTC UE may be included in the MAC header of the connection setup request message. The indicator informing that the UE is the MTC UE may be LCID set to a value in the range from 0b01011 to 0b11000. The connection setup message may be of being fragmented or repeated.

<FIG> is a block diagram illustrating a configuration of an eNB according to an embodiment of the present disclosure.

Referring to <FIG>, an eNB includes a transceiver <NUM>, a controller <NUM>, a scheduler <NUM>, a multiplexer/demultiplexer <NUM>, a control message processor <NUM>, upper layer processors <NUM> and <NUM>.

The transceiver <NUM> is responsible for transmitting data and a determined control signal through a downlink channel and receiving data and the determined control signals through an uplink channel. In the case that a plurality of carriers is configured, the transceiver <NUM> transmits and receives data and control signals through the plural carriers.

The multiplexer/demultiplexer <NUM> is responsible for multiplexing data generated by the upper layer processors <NUM> and <NUM> and the control message processor <NUM> or demultiplexing data received by the transceiver <NUM> to deliver the demultiplexed data to the upper layer processors <NUM> and <NUM>, the control message processor <NUM>, and the controller <NUM>. The control message processor <NUM> processes the control message transmitted by the UE to take a necessary action or generates a control message addressed to the UE to the lower layer.

The upper layer processor <NUM> (or <NUM>) is established per service, processes the data to be transmitted to the S-GW or another eNB into RLC PDU and transfers the RLC PDU to the multiplexer/demultiplexer <NUM>, and processes the RLC PDU from the multiplexer/demultiplexer <NUM> into PDCP SDU to be transmitted to the S-GW or another eNB.

The controller <NUM> controls the transceiver <NUM> to receive the channel state information transmitted by the UE.

The scheduler <NUM> allocates transmission resource to the UE at an appropriate timing in consideration of the buffer state and channel condition of the UE and processes the signal transmitted from the UE or to be transmitted to the UE by means of the transceiver <NUM>.

The control message processor <NUM> transmits an SIB message including the MTC supportability indicator to the UE and, if a message including a newly proposed LCID is received from the UE, the eNB determines that the corresponding UE is the MTC UE so as to transmit data in the manner of being repeated or fragmented.

Although the transceiver <NUM>, the controller <NUM>, the multiplexer/demultiplexer <NUM>, the control message processor <NUM>, and the upper layer processor <NUM> and <NUM> are depicted as separate blocks responsible for different functions in <FIG> for explanation convenience, the configuration is not limited thereto. For example, the controller <NUM> may determine whether the eNB supports MTC UE and, if so, generates a message including an indicator of whether the eNB supports MTC UE, and transmits the message to the UE. This message may be a broadcast message. The broadcast message may be a SIB.

The controller <NUM> may receive a connection setup request message from the UE, determine whether the UE is an MTC UE, check whether the size of the connection setup message to be transmitted to the UE is greater than a determined size allowed for the UE to receive and, if so, transmit the connection setup message in the manner of being repeated or fragmented. The MTC UE indication information may be included in the MAC header of the connection setup request message. The MTC UE indication information may be an LCID set to a value in the range from 0b01011 to 0b11000.

Claim 1:
A method performed by a terminal with reduced capability in a wireless communication system, the method comprising:
receiving (<NUM>), from a base station associated with a cell, system information including information indicating whether a terminal of the reduced capability is allowed to access the cell;
determining whether the terminal with the reduced capability is allowed to access the cell based on the system information;
barring (<NUM>) a selection of the cell, in case that the terminal with the reduced capability is not allowed to access the cell;
transmitting (<NUM>) a random access preamble to the base station, in case that the terminal with the reduced capability is allowed to access the cell;
receiving (<NUM>) a random access response, RAR, message from the base station as a response to the random access preamble;
transmitting (<NUM>) a request message for requesting an establishment of radio resource control, RRC, connection on common control channel, CCCH, to the base station, as a response to the RAR message; and
receiving (<NUM>) a setup message for establishing the RRC connection as a response to the request message,
wherein information indicating that the CCCH is for the terminal of the reduced capability is transmitted with the request message to the base station,
wherein the information indicating that the CCCH is for the terminal of the reduced capability includes a logical channel identifier, LCID, set to a determined value and the determined value is different from <NUM>, and
wherein the terminal of the reduced capability is characterized as having a low maximum data rate compared to a normal terminal.