UE, E-UTRAN base station and method for reducing bandwidth

Abstract

A reduced bandwidth UE, an E-UTRAN base station and a method thereof are disclosed. The reduced bandwidth UE is used to communicate with an Evolved Universal Terrestrial Radio Access Network base station, namely an E-UTRAN base station, and the reduced bandwidth UE includes: a component for establishing a radio resource control connection, namely an RRC connection, with the E-UTRAN base station to enter an RRC connection mode; and a component for obtaining using dedicated signaling when the reduced bandwidth UE is in the RRC connection mode and when there is a change in at least a part of system information.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application date of April 8, 2016, application number 201680021176.2, and invention name “Communication System”. Technical Field

[0002] The present invention relates to mobile communication devices and networks, in particular but not exclusively to mobile communication devices and networks operating according to the Third Generation Partnership Project (3GPP) standards or their equivalents or derivatives. In particular but not exclusively, the present invention is related to the Long Term Evolution (LTE) of UTRAN, including Advanced LTE, known as Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Background Art

[0003] In a mobile (cellular) communication network, a (user) communication device (also referred to as a user equipment (UE), such as a mobile phone) communicates with a remote server or with other communication devices via a base station. In their mutual communication, the communication device and the base station use licensed radio frequencies, which are usually divided into frequency bands and / or time blocks.

[0004] In order to be able to communicate via a base station, a communication device needs to monitor a control channel operated by the base station. One of these control channels, the so-called Physical Downlink Control Channel (PDCCH) and / or the so-called Evolved PDCCH (EPDCCH) in Rel-13, carries scheduling assignments and other control information. The (E)PDCCH serves various purposes. Mainly, the (E)PDCCH is used to convey scheduling decisions, i.e. scheduling assignments for uplink and downlink communications, to the various communication devices.

[0005] The information carried on the (E)PDCCH is called downlink control information (DCI). Physical control channels such as the (E)PDCCH are transmitted on an aggregation of one or more consecutive control channel elements (CCEs), where a control channel element corresponds to nine resource element groups (REGs). Each REG has four resource elements (REs).

[0006] A paging channel is set up on the physical downlink shared channel (PDSCH) (the paging channel is mapped to the physical downlink shared channel (PDSCH)) to notify communication devices of system information changes and / or incoming communications for one or more communication devices (such as mobile terminated calls, short text messages and / or downlink data, etc.). Paging messages are scheduled via (E)PDCCH (but these paging messages are sent on PDSCH). Specifically, in each radio frame sent by the base station, there is at least one predetermined paging opportunity (PO) (there are up to four POs for each radio frame), where each PO is a subframe in which the base station can send control data on the PDCCH to schedule associated paging messages. Each paging message can identify one or more communication devices for which the paging message is sent. Whenever the PO includes a so-called paging identifier, i.e., a paging radio network temporary identifier (P-RNTI) (where the paging identifier is the same for all LTE devices in the cell), each communication device processes the control data and continues to decode the paging message broadcast on the paging channel (at the time-frequency resources identified by the control data).

[0007] In more detail, whenever there is downlink data (or an incoming call) for a particular communication device, the network notifies the base station that may serve the communication device of the data (or call). In response, the base station generates a radio resource control (RRC) paging message and sends the generated paging message for the communication device (by broadcasting via PDSCH). The paging message is scheduled using a PO whose position in a predetermined PO is known to the communication device (e.g., from a system information broadcast of the base station). The paging message includes one or more paging records identifying each communication device being paged and the reason for paging the communication device.

[0008] If the communication device finds the (E)PDCCH addressed by the P-RNTI in the PO (in the control data sent via the PO), the communication device continues to receive and decode the RRC paging message from the PDSCH resource block (RB) identified by the associated control data sent via the PDCCH PO. If a paging record is found for a specific communication device in the decoded RRC paging message, the communication device continues to respond to the paging message (while other communication devices that have not been paged continue to monitor for the next PO). Where appropriate, the paged communication device performs a random access procedure with the base station, thereby establishing a connection with the network and being able to respond to incoming communications associated with the paging message (i.e., the paging record of the communication device).

[0009] Recent developments in telecommunications have seen a massive increase in the use of machine type communication (MTC) devices, which are networked devices configured to communicate and act without human assistance. Examples of such devices include smart meters, which can be configured to take measurements and relay those measurements to other devices via a telecommunications network. Machine type communication devices are also known as machine-to-machine (M2M) communication devices.

[0010] Whenever an MTC device has data to send to a remote "machine" (e.g., a server) or user or data to receive from it, these MTC devices (after appropriate random access procedures, if necessary) connect to the network. MTC devices use communication protocols and standards optimized for mobile phones or similar user equipment. However, once deployed, MTC devices typically work without the need for human supervision or interaction and follow software instructions stored in internal memory. MTC devices can also remain stationary and / or inactive for long periods of time. Specific network requirements to support MTC devices have been specified in 3GPP Technical Specification (TS) 22.368 V13.1.0, the contents of which are incorporated herein by reference.

[0011] For the Release 13 (Rel-13) version of the standard related to MTC devices, it is envisioned to support a reduced bandwidth of 1.4 MHz in both the downlink and uplink. Therefore, some MTC devices will only support a limited bandwidth (typically 1.4 MHz) compared to the total LTE bandwidth, and / or they may have fewer / simplified components. This makes such "reduced bandwidth" MTC devices more economical than MTC devices that support larger bandwidths and / or have more complex components. Beneficially, EPDCCH is transmitted over a relatively narrow spectrum (1.4 MHz), which makes EPDCCH compatible with Rel-13 reduced bandwidth MTC devices.

[0012] The lack of network coverage (e.g. when deployed indoors) combined with the generally limited functionality of MTC devices may result in such MTC devices having low data rates, and therefore there is a risk that the MTC devices may not receive some messages or channels such as EPDCCH, etc. In order to mitigate this risk, it has been proposed to increase the coverage of transmissions to support such MTC devices (e.g. corresponding to 20 dB for frequency division duplex (FDD) transmissions).

[0013] One approach proposed to enhance coverage for so-called "coverage enhanced MTC devices" is to repeat the same information (e.g., DCI sent via EPDCCH) across multiple subframes (e.g., two, three, or four subframes). In other words, for a coverage enhanced (CE) MTC device, the base station repeats the transmitted information in the time domain (the base station retransmits the same information in one or more subframes after the subframe in which the information was first transmitted). Such a coverage enhanced MTC device may be configured to combine multiple copies of the (same) information received in multiple subframes, and after combining the received information, the coverage enhanced MTC device is more likely to be able to successfully decode the received information than based on a single copy of the transmitted information. Similar to the repetition of the same information performed by the base station, the coverage enhanced MTC device is also configured to repeat (in the time domain) the information sent to the base station in order to successfully receive the information at the base station.

[0014] In practice, MTC devices may be deployed in different locations, and MTC devices may experience different channel conditions. Therefore, it may be necessary to customize the number of repetitions for each device's situation or coverage level, and each MTC device informs its serving base station of the required coverage amount (e.g., 5dB / 10dB / 15dB / 20dB coverage enhancement) so that the base station can adjust its control signaling appropriately.

[0015] Paging messages are sent separately for MTC devices (e.g., low complexity and / or coverage enhanced MTC devices) and for other (non-MTC) communication devices such as traditional mobile phones, etc. In addition, 3GPP envisions that paging messages for MTC devices can be sent in different subbands depending on the operating mode of the MTC device (e.g., whether the MTC device is operating in normal coverage mode (0dB CE level), 5dB CE level, 10dB CE level, or 15dB CE level). Summary of the invention

[0016] Problem that the invention aims to solve

[0017] Therefore, it can be seen that where paging is targeted to CE MTC devices, it would be necessary to support repetition of transmissions. However, current paging procedures do not support such repetitions.

[0018] Furthermore, even if repetitions are supported, there may be uncertainty at the base station regarding the type of MTC device being paged and / or the level of coverage enhancement required for the MTC device, which may result in using an incorrect number of repetitions and / or sending the paging message in the wrong time-frequency resource and / or using the wrong format. For example, if (as currently proposed by some 3GPP participants) the CE level is linked to a specific 1.4 MHz sub-band (paging location) over which paging communications are broadcast, then this uncertainty regarding the CE level may result in some low-complexity MTC devices being tuned to a 1.4 MHz bandwidth outside of the sub-band over which paging messages (and / or associated control data) are sent for these MTC devices. However, there is no simple way to ensure that the CE level employed by a communication device is the same as the CE level employed by the base station (for the communication device).

[0019] Therefore, the present invention seeks to provide a system, an apparatus and a method that at least partially solve the above problems.

[0020] Solutions for solving problems

[0021] In one aspect, the present invention provides a base station for a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, and the base station comprises: a component for determining that it is necessary to notify the MTC device of an existing system information update; a component for notifying any MTC device in idle mode of the system information update by sending a notification using a paging message; and a component for providing the system information to any MTC device in a radio resource control connection mode, i.e., an RRC connection mode, using MTC device-specific signaling.

[0022] In one aspect, the present invention provides a machine type communication device, i.e., an MTC device, for communicating with a base station, the MTC device comprising: a component for forming a radio resource control connection, i.e., an RRC connection, with the base station to enter an RRC connection mode; and a transceiver configured to obtain system information associated with a cell of the base station using dedicated signaling when in the RRC connection mode.

[0023] In one aspect, the present invention provides a method performed by a base station used in a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, the method comprising the following steps: determining that it is necessary to notify the MTC device of a system information update; notifying any MTC device in idle mode of the system information update by sending a notification using a paging message; and providing the system information to any MTC device in a radio resource control connection mode, i.e., an RRC connection mode, using MTC device-specific signaling.

[0024] On the one hand, the present invention provides a method performed by a machine type communication device, i.e., an MTC device, in a communication system, wherein in the communication system, the MTC device communicates via a base station, and the method comprises the following steps: forming a radio resource control connection, i.e., an RRC connection, with the base station to enter an RRC connection mode; and when in the RRC connection mode, using dedicated signaling to obtain system information associated with a cell of the base station.

[0025] Aspects of the present invention extend to corresponding systems, methods and computer program products such as computer-readable storage media having instructions stored thereon, which are operable to program a programmable processor to perform the methods as described in the aspects and possibilities set out above or in the claims, and / or to program a suitably adapted computer to provide an apparatus as recited in any one of the claims.

[0026] Each feature disclosed in this specification (which term includes the claims) and / or shown in the drawings may be included in the present invention alone (or in combination with any other disclosed and / or illustrated features). Specifically, but not restrictively, features according to any claim dependent on a particular independent claim may be introduced into the independent claim in any combination or alone.

[0027] Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematically illustrates a telecommunication system to which embodiments of the present invention may be applied;

[0029] Figure 2 It is shown Figure 1 A block diagram of the main components of the communication device shown;

[0030] Figure 3 It is shown Figure 1 A block diagram of the main components of a base station is shown;

[0031] Figure 4 Shown in Figure 1 A typical way in which paging can be implemented in the system shown;

[0032] Figure 5 Shown in Figure 1 Typical paging configuration options that can be employed in the system shown;

[0033] Figure 6 Shown in Figure 1Another typical paging configuration option that can be used in the system shown;

[0034] Figure 7 Shown in Figure 1 Another typical paging configuration option that can be used in the system shown;

[0035] Figure 8 Shown in Figure 1 Another typical paging configuration option that can be used in the system shown;

[0036] Fig. 9 Shows the Figure 1 An exemplary manner in which a communication device in the illustrated system may determine a required coverage enhancement level (to be employed in a particular cell); and

[0037] Fig.10 Shows the Figure 1 Another typical way in which a communication device in the system may determine a required coverage enhancement level (to be employed in a particular cell) is shown. DETAILED DESCRIPTION

[0038] <Overview>

[0039] Figure 1 Schematically shows a mobile (cellular) telecommunication system 1 in which user devices 3 (such as mobile phones 3-1 and MTC devices 3-2) can communicate with each other and / or other communication nodes via E-UTRAN base stations 5 (denoted as "eNBs") and a core network 7. As will be appreciated by those skilled in the art, although Figure 1 In the figure, one mobile phone 3-1, one MTC device 3-2 and one base station 5 are shown for illustration purposes, but the mobile (cellular) telecommunication system will typically include other base stations and communication devices when implemented.

[0040] Each communication device 3 may belong to one or more categories of UE. The first category of UE includes communication devices that only support earlier release versions (e.g., Rel-8, Rel-9, Rel-10, Rel-11 and / or Rel-12) of the LTE standard. Such communication devices are generally referred to as traditional UEs (assuming that the base station 5 is operating according to Rel-13 of the LTE standard). It should be understood that some communication devices belonging to this category may not support EPDCCH (but only support PDCCH). The second category of UE includes communication devices that support the current release version (e.g., Rel-13 and / or subsequent versions) of the LTE standard. The third category of UE includes reduced bandwidth UEs that cannot communicate on the entire bandwidth available in the cell of the base station 5 (e.g., Rel-13 MTC devices that can only use 1.4MHz bandwidth). The fourth category of UE includes UEs (e.g., some MTC devices) that need to simplify and / or relax coverage enhancement of certain base station functions (but such coverage enhancement UEs can normally support other functions).

[0041] In this example, the mobile telephone 3-1 comprises a Rel-13 UE and the MTC device 3-2 comprises a reduced bandwidth MTC device (which may also be configured for an appropriate level of coverage enhancement). Figure 1 It is not shown in the figure, but it is assumed that there are multiple other MTC devices in the cell of the base station 5.

[0042] The base station 5 is connected to the core network 7 via an S1 interface. The core network 7 includes: a gateway for connecting to other networks such as the Internet and / or to a server hosted outside the core network 7; a mobile management entity (MME) for tracking the location of the communication device 3 (e.g., a mobile phone and an MTC device) within the communication network 1; and a home user server (HSS) for storing subscription-related information (e.g., information for identifying which communication device 3 is configured as a machine type communication device) and for storing control parameters specific to each communication device 3; etc.

[0043] The base station 5 is configured to transmit a physical downlink control channel (PDCCH) and an evolved PDCCH (EPDCCH) for reception by a communication device 3 located within the cell of the base station 5. (E)PDCCH allocates uplink resources and downlink resources to the communication device 3. One difference between PDCCH and EPDCCH is that EPDCCH uses a relatively narrow spectrum (1.4 MHz) that makes the EPDCCH compatible with Rel-13 reduced bandwidth MTC devices, while PDCCH uses a wider spectrum to provide backward compatibility with legacy communication devices.

[0044] The so-called common search space (CSS) is a search space used by all / multiple UEs in a cell to blindly decode the PDCCH carrying downlink control information (DCI) common to all / multiple communication devices 3. For example, the CSS may carry downlink control information (DCI) for: a system information block (SIB) containing information about cell access parameters; a random access channel (RACH) message; and / or a paging channel (PCH). In LTE Rel-13, the CSS (also called "eCSS") forms part of the search space of the EPDCCH.

[0045] Due to the reduced bandwidth of 1.4 MHz in the downlink and uplink, the MTC device 3-2 cannot receive PDCCHs densely dispersed across the cell bandwidth (i.e., the PDCCHs may be transmitted at frequencies outside the 1.4 MHz supported by the MTC device 3-2). However, the MTC device 3-2 can receive EPDCCH CSS (eCSS) transmitted on 6RBs, i.e., within the 1.4 MHz band supported by the MTC device 3-2.

[0046] To support MTC devices, the cell bandwidth of the base station 5 includes multiple sub-bands (e.g., non-overlapping sub-bands), where each sub-band includes 6 RBs (or less). Beneficially, since the reduced bandwidth MTC devices can communicate over a maximum bandwidth of 1.4 MHz (which roughly corresponds to 6 RBs), the communication device 3-2 can send and receive (eCSS and other) data over the specific sub-band to which its transceiver is currently tuned.

[0047] Paging messages are sent separately for MTC devices (e.g., low complexity and / or coverage enhanced MTC devices) and for other communication devices. Paging messages for MTC devices support PDSCH subframe bundles / repetitions with multiple bundle sizes / repetition levels (depending on the required level of coverage enhancement). Advantageously, information is provided to the base station 5 that pages the communication device 3-2, enabling the base station 5 to determine that the communication device 3-2 includes a low complexity (reduced bandwidth) MTC device and / or an MTC device configured for coverage enhancement. Information is provided to the base station 5 that enables the base station 5 to determine the amount of coverage enhancement (repetition) required during the transmission of the paging message.

[0048] Advantageously, the base station 5 and the MTC device 3-2 are configured to use the same CE level for paging (and even other communications) in the cell of the base station 5. The appropriate CE level can be determined by the base station 5 or the MTC device 3-2 (e.g., based on signal strength or quality) (and notified to the other party). The appropriate CE level is synchronized between the base station 5 and the MTC device 3-2 (directly or via the core network 7). Advantageously, the core network (e.g., MME) is notified of the appropriate CE level for the communication device, so that when paging is initiated, the MME is able to instruct each paging base station for each cell of a particular tracking area (CA) to use the appropriate CE level in that cell for the MTC device being paged.

[0049] It should be understood that in the case where the communication device to be paged is operating in a so-called idle state, the location of the communication device is only known to the MME on a Tracking Area (TA) basis (not on a cell level). Therefore, the MME indicates all base stations within the TA (including, for example, Figure 1 The base stations 5) send an appropriately formatted RRC paging message (including a paging record for the communication device) by using the cells of these base stations regarding the CE level required by the paged communication device. The term idle state as used herein refers to an operation mode in which the communication device is not currently sending / receiving user data on its dedicated radio bearer, but the transceiver of the communication device may be active (for example, the transceiver may still receive broadcast data and / or perform signal measurements, etc.).

[0050] Like conventional paging, a paging occasion (PO) is configured for paging MTC devices. However, advantageously, a PO defines multiple subframes ("bundles") in a particular subband (eg, by defining the start point of the subframe bundle (or index of the first subframe)).

[0051] In the example described in more detail below, the system may employ scheduling of paging transmissions via ePDCCH (e.g., layer 1 (L1) scheduling). However, in a particularly beneficial example, uncontrolled paging is used, i.e., paging without scheduling associated resources in the ePDCCH. Instead, a paging message is sent on a transport block of a predetermined size (and on a predetermined subband) that can be received by each communication device 3 within the cell of the base station 5.

[0052] The subframe bundle defined with PO is the following subframes, in which the MTC device is used to monitor the repetition of the ePDCCH scheduled for the paging message when the paging transmission is scheduled using ePDCCH. The subframe bundle defined with PO is the following subframes, in which the MTC device is used to monitor the repetition of the PDSCH for the paging message when the paging transmission is not scheduled using ePDCCH.

[0053] The base station 5 may configure different resources and / or paging areas for each CE level so that paging for MTC devices with different CE levels between different resources and / or paging areas is effectively separated. However, in a particularly beneficial example, paging message transmission is not separated for different coverage enhancement levels (so that all MTC devices can benefit from scheduled or uncontrolled paging in the same subband regardless of the CE level). In this case, paging message transmission may be implemented with or without the use of ePDCCH.

[0054] In summary, the communication system described above supports various beneficial options for paging communication devices within a cell of a base station by paying special attention to the limitations of MTC devices. Paging messages can be scheduled dynamically and (where applicable) according to the required level for each MTC device without (significantly) affecting the traditional and / or conventional communication devices in the cell.

[0055] <Communication device>

[0056] Figure 2 It is shown Figure 1 3 is a block diagram of the main components of the communication device 3 shown. The communication device 3 may be an MTC device or a mobile (or "cellular") phone configured as a machine type communication device. The communication device 3 comprises a transceiver circuit 31 operable to send signals to and receive signals from a base station 5 via at least one antenna 33. Typically, the communication device 3 also comprises a user interface 35 enabling a user to interact with the communication device 3, however the user interface 35 may be omitted for some MTC devices.

[0057] The operation of the transceiver circuit 31 is controlled by the controller 37 according to the software stored in the memory 39. The software includes an operating system 41, a communication control module 43, a scheduling determination module 44, an MTC module 45 and a paging module 47.

[0058] The communication control module 43 controls the communication between the communication device 3 and the base station 5 and / or (via the base station 5) and other communication nodes.

[0059] The scheduling determination module 44 monitors the transmission of the base station 5 in a predetermined PO (where applicable), and determines whether the monitored PO includes control data for scheduling paging transmissions. If the monitored PO includes such control data, the scheduling determination module 44 determines the communication resources (e.g., subframes / subbands) associated with the paging transmission. In the case of non-control being used, the scheduling determination module 44 maintains information identifying the resources via which non-control paging messages can be sent, and instructs the paging module 47 to decode the paging messages sent in the information.

[0060] The MTC module 45 is operable to perform machine type communication tasks. For example, the MTC module 45 may collect data for transmission to a remote server (via the transceiver circuit 31) (e.g., periodically and / or upon detection of a trigger). The MTC module 45 is also responsible for obtaining (determining and / or obtaining from the base station 5) the appropriate CE level to be used in the cell of the base station 5 serving the communication device 3.

[0061] The paging module 47 receives and processes paging messages addressed to the communication device 3 (via the appropriate communication resources determined by the scheduling module 44 ).

[0062] <Base Station>

[0063] Figure 3 It is shown Figure 1 5 is a block diagram of the main components of the base station 5 shown. The base station 5 comprises an E-UTRAN base station (eNB) comprising a transceiver circuit 51 operable to send signals to and receive signals from the communication device 3 via one or more antennas 53. The base station 5 is also operable to send signals to and receive signals from the core network 7 via an appropriate core network interface 55 (such as an S1 interface, etc.). The operation of the transceiver circuit 51 is controlled by a controller 57 according to software stored in a memory 59.

[0064] The software includes an operating system 61 , a communication control module 63 , a paging module 65 , a system information module 67 and an MTC support module 69 .

[0065] The communication control module 53 controls communication with the communication device 3 .

[0066] The paging module 65 generates and sends (via the communication control module 63 ) a paging message to the communication device 3 located within the cell of the base station 5 .

[0067] The system information module 67 is responsible for broadcasting system information (such as the configuration of the cell of the base station 5) and / or other broadcast information for reception by the communication device 3 located in the cell of the base station 5. For example, the broadcasting unit sends a paging message (generated by the paging module 65) through an appropriate PO.

[0068] The MTC support module 69 processes (generates, sends and receives) messages for MTC devices in the cell of the base station 5. The MTC support module 69 is responsible for ensuring that each such message is sent using the required number of repetitions (depending on the CE level if configured) and using the appropriate time and frequency resources (in a given subframe / within the 1.4MHz band supported by the MTC device). The MTC support module 69 is also responsible for obtaining (determining and / or obtaining from the core network 7) the appropriate CE level to be adopted in the cell of the base station 5 when communicating with the communication device 3.

[0069] In the above description, for ease of understanding, the communication device 3 and the base station 5 are described as having a plurality of discrete modules. Although these modules may be provided in this manner for certain applications, for example, in a case where an existing system has been modified to implement the present invention, in other applications, for example, in a system designed from the outset with the features of the present invention in mind, these modules may be built into the entire operating system or code, and thus these modules may not be discernible as discrete entities.

[0070] <Operation-General>

[0071] Figure 4 Shown in Figure 1 A typical way of implementing paging in the illustrated communication system 1 is shown. Specifically, in this example, a paging message is sent on a PDSCH without sending any associated control data (DCI) on a (E)PDCCH for scheduling paging transmissions. Advantageously, the location (e.g., time / frequency resources) and size of the paging message are configured via a system information broadcast (e.g., determined by an associated transport block size (TBS)).

[0072] In addition, if necessary, the location and / or size of the paging message can also be updated via system information broadcast. For example, the base station 5 can indicate / adjust the TBS for the paging message via system information based on at least one of the following:

[0073] - the (current) average MTC paging load in the cell;

[0074] - the number of connected UEs in the cell; and

[0075] - (measured / determined / estimated) resource usage of base stations (not limited to MTC paging).

[0076] In addition, other paging-related information may also be indicated via system information, such as the PO currently configured for the cell of the base station 5 (e.g., the starting point of the PO in the ePDCCH / PDSCH), etc. It should be understood that different POs may be configured for each category of communication devices and / or for each CE level (and the POs may be broadcast via system information).

[0077] <Operation-Paging for System Information Change>

[0078] In order to notify a communication device 3 located within a cell of a base station 5 of a change in system information (e.g., PO configuration, paging TBS and / or channel configuration, etc.), the base station 5 is configured to generate and send a suitably formatted paging message to the communication device 3. System information change paging is performed using a 1-bit indicator (known as the "systemInfoModification" bit) that is sent along with other periodic (UE-specific) paging records (if present). In the event that any system information element is to be changed, the base station 5 sends this indicator bit on all POs for all communication devices within its cell, thereby ensuring that each communication device 3 has an opportunity to receive the updated system information without delay. Each communication device that receives a paging message including the system information change indicator bit (via any PO) continues to obtain the updated system information by listening to the next system information broadcast (e.g., at the boundary of the "BCCH modification time period") .

[0079] However, it should be understood that for communication devices (at least for MTC devices) operating in the "RRC_IDLE" and "RRC_CONNECTED" states, system information changes may be notified in different ways.

[0080] System Information Changes for UEs in RRC_IDLE

[0081] It will be appreciated that for communication devices in idle mode, the system information modification indicator is sent together with the normal paging record. In this case, the base station 5 needs to send the system information change indicator bit on all POs, thereby addressing all types of communication devices (including MTC devices and traditional UEs).

[0082] Optionally, for example, if the system information changes relatively frequently, paging for system information modification can be separated from normal paging. In this case, preferably, paging for system information is sent in a predetermined common subband (e.g., a central subband), and all communication devices need to be configured to operate on the common subband (at least during the PO) and monitor the system information modification bit in one or more POs of the subband. As a result, during the paging opportunity for system modification in the common subband, MTC devices cannot be scheduled in other subbands. However, in this case, it is not necessary to include the "systemInfoModification" bit in every PO of each subband, although some additional paging monitoring of MTC devices is required, which may slightly increase power consumption.

[0083] System Information Changes for UEs in RRC_CONNECTED

[0084] It is possible that a communication device in RRC_CONNECTED mode is scheduled on a subband different from the subband used for monitoring paging. In any case, it should be understood that, as described above, the system information modification indicator can be sent together with the normal paging record, that is, the base station 5 needs to send the system information change indicator bit on all POs of each subband to reach all types of communication devices. However, this option may require a communication device in RRC_CONNECTED mode to re-tune to its associated paging subband to obtain system information change notifications.

[0085] Therefore, in this system, dedicated signaling is used to notify RRC_CONNECTED communication devices (at least MTC devices) of changes in system information. For example, if there is an ongoing data transmission for a particular communication device, the updated system information (or at least the changed part of the information) can be multiplexed with other data being sent to the communication device. As a result, since the updated system information is sent via unicast transmission, the RRC-CONNECTED communication device is not required to monitor the associated PO for system information modification. This may improve the operation of communication devices (particularly MTC devices operating on limited bandwidth).

[0086] In another option, a communication device operating in RRC_CONNECTED may be forced to obtain system information by releasing the RRC connection of the communication device. This may be beneficial, for example, in the case where there is no ongoing data transmission for the communication device (thus, the risk of data loss is kept to a minimum). Once the RRC connection of the communication device is released, the communication device continues (according to the default procedure) to read the system information transmitted via the broadcast channel.

[0087] It should be understood that the base station 5 (depending on the implementation) can adopt both the unicast-based option and the RRC release-based option.

[0088] <Operation-PO Configuration>

[0089] In the current LTE standard, a Paging Occasion (PO) is defined as a subframe where there may be a P-RNTI sent on the PDCCH for scheduling paging messages. A radio frame may contain 1 to 4 POs. In the case of DRX, the UE needs to monitor only one PO for each DRX cycle.

[0090] However, in the present system, PO is defined so that (where appropriate) repetition for MTC devices is also supported. Specifically, PO in this system is defined as (the starting point of) a subframe bundle in a particular subband, where:

[0091] - In case ePDCCH is needed for paging transmission, the UE monitors the repetition of ePDCCH for paging message scheduling; or

[0092] - In case ePDCCH is not needed for paging transmission, the UE monitors the repetitions of PDSCH for paging messages.

[0093] Furthermore, there may be different POs for different subbands (eg, to support MTC devices with different CE levels).

[0094] Figures 5 to 8 Various PO configuration options in the system and further details of the paging transmissions thus generated are shown.

[0095] Specifically, Figure 5 and 6 The illustrated example shows a scenario where paging message transmissions are separated for different coverage enhancement levels.

[0096] Figure 5 The paging message transmission using ePDCCH (eCSS) is shown. In this example, scheduling information (e.g., time-frequency resources, MCS / TBS) that enables MTC devices to obtain paging messages on PDSCH is dynamically indicated in the ePDCCH. In this case, different P-RNTIs and / or different eCSSs can be used for each CE level.

[0097] Figure 6 The paging message transmission without using ePDSCH is shown. This solution may also be referred to as "uncontrolled" paging, i.e., scheduling information (e.g., time-frequency resources, MCS / TBS) that enables MTC devices to obtain paging messages on PDSCH is not dynamically indicated in the ePDCCH, but the scheduling information is predefined or indicated in the system information (or forms part of the system information). In this case, different time and / or frequency resources (within the PDSCH) may be allocated for different CE levels. It should be understood that in Figure 6 In the PDSCH-based scenario shown, effectively, for example, as described above with reference Figure 4 As described above, uncontrolled paging can be implemented for each CE level.

[0098] exist Figure 7 and 8 In the example shown, paging message transmissions are not separated for different coverage enhancement levels. Figure 7 shows paging message transmission using ePDCCH, and Figure 8 FIG. 4 shows a paging message transmission without using ePDCCH (eg, a situation where ePDCCH is not used or cannot be used for paging transmission). Figure 8 In the scenario shown, effectively, for example as referenced above Figure 4 As described above, uncontrolled paging can be achieved.

[0099] <Operation-CE level determination>

[0100] A number of options for determining an appropriate CE level for a particular MTC device 3-2 in a cell of a base station 5 are described below to ensure that both the MTC device 3-2 and its serving base station 5 employ the same CE level in their communications with each other.

[0101] Fig. 9 The option is shown where a serving base station 5 (denoted "eNB") is responsible for the decision regarding which CE level a particular MTC device (denoted "UE") should adopt in a given cell.

[0102] As shown in step S92, the base station 5 is configured (using its MTC support module 69) to perform a random access procedure (in the case of a random access procedure) between the base station 5 and the MTC device 3-2 in the cell of the base station 5. Fig. 9 denoted as “PRACH” in the figure) (as generally shown in step S91), to determine an appropriate CE level for the MTC device 3-2.

[0103] Once the base station 5 determines the appropriate CE level for the MTC device 3 - 2 , the base station 5 notifies (in step S93 ) the core network 7 (eg MME / HSS) which stores the information for subsequent use (eg for paging the MTC device 3 - 2 via the base station 5 ).

[0104] As generally shown in step S94, the base station 5 may also inform the MTC device 3-2 of the determined CE level for the cell of the base station 5 in a separate message or as part of the random access procedure (e.g., step S94 may constitute part of step S91). It should be understood that the base station 5 may be configured to implicitly inform the MTC device of the CE level, for example by adopting a specific number of repetitions (during and / or after the random access procedure) corresponding to the determined CE level.

[0105] It should be understood that there are multiple ways in which the base station 5 can obtain an appropriate CE / repetition level for the MTC device based on the RACH process, including, for example:

[0106] 1) MTC devices with different CE levels may use different preamble resources (with corresponding different numbers of repetitions) according to an appropriate predetermined relationship mapping between the preamble resources and the corresponding CE levels. In this case, the base station may determine the appropriate CE level based on which preamble resources the MTC device 3-2 uses (and / or based on the number of repetitions used by the MTC device 3-2). However, in this case, optionally, the base station may also be configured to use a CE level different from the CE level represented by the relationship mapping between the preamble resources and the corresponding CE level (for example, in the case where the base station 5 is able to successfully decode the preamble transmission of the MTC device by combining fewer repetitions than required for that CE level).

[0107] 2) Otherwise, if there is no associated preamble resource set configured for each different CE level, the base station 5 may be configured to determine the coverage level based on the number of repetitions required for successful decoding of the preamble sent by the MTC device 3 - 2 .

[0108] In addition, for example, if the MTC device 3-2 has never been connected to the cell / or the MTC device 3-2 has not been connected to the cell within a predetermined time window, one or more of the following options may also be used:

[0109] 3) The base station 5 may be configured to adopt a maximum and / or default CE / repetition level for the MTC device 3-2 in cells to which the MTC device 3-2 has never connected (or the MTC device 3-2 has not connected within a predetermined time window).

[0110] 4) If the MTC device 3-2 is reselected to a new cell (of the base station 5), an appropriate RACH process may be triggered (using the MTC module 45) to enable the base station 5 to detect the associated CE level of the MTC device 3-2 in the new cell. Otherwise, the MTC device 3-2 may not be paged in the new cell until the MTC device 3-2 performs a RACH process via the cell (but the MTC device 3-2 is still being paged in other cells), or the MTC device 3-2 is paged by adopting the maximum and / or default CE / repetition in the new cell.

[0111] It should be understood that if the required CE level of the MTC device changes (for example, based on its own estimation) in a cell (particularly in the current cell in which the MTC device is currently residing), an appropriate RACH process may be triggered (using the MTC module 45) to enable the base station 5 to update the associated CE level stored for the MTC device (for that cell).

[0112] Thus, beneficially, this option enables more control for the base station 5 in the determination of the appropriate CE level. In this case, the same MTC device may have different CE / repetition levels in different cells. However, such cell-specific CE levels may be stored in the core network 7 (MME / HSS) for each MTC device, so that each MTC device may be paged in any cell using the appropriate CE level (and repetition) required for that cell. Thus, in the case where the MME initiates paging of the MTC device 3-2, in step S95, the MME includes in its paging request the cell ID and the respective associated CE / repetition levels for each cell to be paged for the MTC device 3-2.

[0113] As generally shown in step S96, since both the base station 5 and the MTC device 3-2 adopt the same CE level, the base station 5 can be operated to send (and the MTC device 3-2 can be operated to monitor) resources at the correct PO corresponding to the CE level. Thus, in step S97, when the base station 5 sends a paging message (scheduled via the PO in S96) to the MTC device 3-2, the base station 5 can apply the correct CE level (and the required number of repetitions if any) to the MTC device 3-2.

[0114] Fig.10 An option is shown where the MTC device 3-2 is responsible for the decision regarding which CE level the MTC device 3-2 adopts in a given cell.

[0115] Specifically, in this case, the judgment of the MTC device 3-2 (in step S102) is based on the measurement of the (downlink) wireless conditions of multiple cells (e.g., all detected cells) near the MTC device 3-2. It should be understood that the MTC device 3-2 can measure the wireless conditions for at least its current serving cell (e.g., the cell of the base station 5).

[0116] Once the MTC device 3-2 determines the appropriate CE level for a particular cell (or a set of CE levels for multiple cells) in step S102, the MTC device 3-2 notifies the core network 7 (e.g., MME / HSS) of the applicable CE level and (optionally) the corresponding cell ID. It should be understood that the MTC device 3-2 can report the applicable CE level (and, if present, the corresponding cell ID) as part of a capability report or the like.

[0117] It should be understood that if the MTC device 3-2 determines (for example, based on its own estimation / signal quality measurement) that the required CE level (in at least one cell) has changed (particularly in the current cell in which the MTC device 3-2 is currently residing), the MTC device 3-2 may notify the core network 7 and update the associated CE level stored for the MTC device (for at least one cell in which the CE level has changed).

[0118] It should be understood that the MTC device 3-2 can be configured to report / update the CE level if one or more of the following conditions are met: i) the MTC device performs an attachment process; ii) the MTC device finds a new neighboring cell as a paging cell; and iii) the MTC device determines a change in the required CE level and / or a change in the wireless conditions in the cell.

[0119] The core network 7 stores the information for subsequent use (eg, for paging the MTC device 3 - 2 in step S105 ). Steps S105 to S107 correspond to the above-mentioned steps S95 to S97 , and thus for simplicity, descriptions of these steps are omitted here.

[0120] A benefit associated with this option is that the required CE levels for multiple cells (including, for example, potential paging cells of the MTC device 3 - 2 ) may be measured simultaneously and reported to the core network 7 .

[0121] <Modifications and Replacements>

[0122] Detailed exemplary embodiments are described above. As will be appreciated by those skilled in the art, many modifications and substitutions may be made to the exemplary embodiments described above while still benefiting from the inventions implemented therein.

[0123] In the above description, repetition in the time domain is assumed for all transmissions. However, for simplicity, Figures 4 to 10 These repetitions are omitted.

[0124] References Figures 5 to 8 A number of options are described. It should be understood that these options are not mutually exclusive and any of these options may be combined within the same system (within one cell and / or in neighboring cells). For example, a base station may be configured to change from one operating mode to another operating mode, e.g. periodically, depending on the number / type of MTC devices in its cell, on the total load in the cell and / or on the type of communication (e.g. broadcast / unicast).

[0125] It should be understood that although the communication system is described in terms of a base station operating as an E-UTRAN base station (eNB), the same principles may apply to a base station operating as a macro base station or a micro base station, a femto base station, a relay node providing elements of base station functionality, a home base station (HeNB), or other such communication nodes.

[0126] In the above exemplary embodiments, an LTE telecommunications system is described. As will be appreciated by those skilled in the art, the techniques described in this application may be used in other communication systems, including earlier 3GPP type systems. Other communication nodes or devices may include user devices such as personal digital assistants, laptop computers, web browsers, etc.

[0127] In the above exemplary embodiments, the base station and the communication device each include a transceiver circuit. Typically, the circuit will be composed of a dedicated hardware circuit. However, in some exemplary embodiments, a portion of the transceiver circuit can be implemented as software running through a corresponding controller.

[0128] In the above exemplary embodiments, multiple software modules are described. As will be appreciated by those skilled in the art, software modules may be provided in compiled or uncompiled form, and may be provided as signals to a base station or user device via a computer network or provided on a recording medium. In addition, the functions performed by part or all of the software may be performed using one or more dedicated hardware circuits.

[0129] It should be understood that the base station may include: a component for receiving a paging request for paging at least one MTC device from a core network entity; a component for determining a paging opportunity at which the at least one MTC device will be sent paging-related information, wherein the paging opportunity identifies a plurality of subframes in which the paging-related information will be first sent and then repeated; and a component for sending the paging-related information in the plurality of subframes identified by the paging opportunity and then repeating the paging-related information.

[0130] The paging related information may include scheduling information identifying time and / or frequency resources to be used to send a paging message to the at least one MTC device, and the multiple subframes identified by the paging occasion may be subframes in which a control channel carrying the paging related information is to be sent.

[0131] The at least one MTC device may include at least one coverage enhanced MTC device having a first coverage enhancement level and at least one coverage enhanced MTC device having a second coverage enhancement level different from the first coverage enhancement level.

[0132] In this case, the paging-related information may include: a first paging identifier (e.g., a wireless network temporary identifier), used to identify paging-related information for at least one coverage enhanced MTC device with a first coverage enhancement level; and a second paging identifier (e.g., a different wireless network temporary identifier), used to identify paging-related information for at least one coverage enhanced MTC device with a second coverage enhancement level.

[0133] Paging-related information for at least one coverage enhanced MTC device with a first coverage enhancement level may be first sent in a control channel within a first subframe, and paging-related information for at least one coverage enhanced MTC device with a second coverage enhancement level may be first sent in a control channel within a second subframe different from the first subframe.

[0134] Paging-related information for at least one coverage enhanced MTC device with a first coverage enhancement level may be sent in a control channel within at least one subframe, wherein in the at least one subframe, paging-related information for at least one coverage enhanced MTC device with a second coverage enhancement level is also sent using the same control channel.

[0135] The paging related information may include at least one paging message for the at least one MTC device, and the multiple subframes identified by the paging occasion may be subframes in which the at least one paging message will be sent and then repeated. In this case, the base station may also include a component for performing the following operations: sending scheduling information for identifying resources to be used for sending the at least one paging message to the at least one MTC device in a system information block. For example, the scheduling information may include information identifying a transport block size, i.e., a TBS, for the requested paging.

[0136] The at least one MTC device may include at least one coverage enhanced MTC device having a first coverage enhancement level and at least one coverage enhanced MTC device having a second coverage enhancement level different from the first coverage enhancement level.

[0137] In this case, a first predetermined frequency resource may be used to send a paging message for at least one coverage enhanced MTC device with a first coverage enhancement level, and a second predetermined frequency resource different from the first predetermined frequency resource may be used to send a paging message for at least one coverage enhanced MTC device with a second coverage enhancement level.

[0138] A paging message for at least one coverage enhanced MTC device with a first coverage enhancement level may be first sent in a data channel within a first subframe, and a paging message for at least one coverage enhanced MTC device with a second coverage enhancement level may be first sent in a data channel within a second subframe different from the first subframe.

[0139] A paging message for the at least one coverage enhanced MTC device with a first coverage enhancement level may be sent in a data channel within at least one subframe, wherein in the at least one subframe, a paging message for the at least one coverage enhanced MTC device with a second coverage enhancement level is also sent in the same data channel.

[0140] If the at least one MTC device includes at least one coverage-enhanced MTC device, the base station may further include a component for identifying a coverage enhancement level associated with the at least one coverage-enhanced MTC device, and the component for sending the paging-related information and then repeating the paging-related information may be configured to repeatedly send the paging-related information a number of times defined by the coverage enhancement level.

[0141] The paging request may include information identifying the coverage enhancement level, and wherein the means for identifying the coverage enhancement level associated with the at least one coverage enhanced MTC device is configured to identify the coverage enhancement level based on the information identifying the coverage enhancement level in the paging request.

[0142] The component for identifying the coverage enhancement level associated with the at least one coverage enhanced MTC device may be configured to identify the coverage enhancement level based on information (e.g., a random access preamble sequence index) obtained during a process for setting up a random access channel (RACH) with the at least one coverage enhanced MTC device.

[0143] If the MTC device for the at least one coverage enhancement cannot determine each coverage enhancement level, the component for sending the paging-related information and then repeating the paging-related information may be configured to repeat the paging-related information for a number of repetitions defined according to a predetermined (e.g., maximum and / or default) coverage enhancement level.

[0144] In the above exemplary embodiments, a machine type communication device and a mobile phone are described. However, it should be understood that a mobile phone (and similar user equipment) may also be configured to operate as a machine type communication device. For example, the mobile phone 3-1 may include an MTC module 45 (and / or provide the functionality of the MTC module 45).

[0145] Examples of MTC applications

[0146] It should be understood that each communication device may support one or more MTC applications. Some examples of MTC applications are listed in the following table (source: 3GPP TS22.368 V13.1.0, Annex B). This list is not exhaustive and is intended to indicate the range of machine type communication applications.

[0147] [Table 1]

[0148]

[0149] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0150] The following details the manner in which the present invention may be implemented in the currently proposed 3GPP standard. Although various features are described as essential or required, this may only be the case for the proposed 3GPP standard, for example due to other requirements imposed by the proposed 3GPP standard. Therefore, these statements should in no way be interpreted as limiting the present invention.

[0151] Title: Paging for Rel-13 MTC UE

[0152] 1. Introduction

[0153] There is extensive need for repetition for both broadcast channels and unicast channels addressed to MTCe UEs including low complexity UEs in normal coverage and coverage enhancement, thus requiring a redesign of the paging transmission procedure for Rel-13 MTCe UEs.

[0154] In this article, we share our perspectives on the following questions:

[0155] 1. Is dynamic L1 scheduling, i.e. ePDCCH, required for paging transmission?

[0156] 2. How to perform paging for system information changes?

[0157] 3. Is paging message transmission separate for different types of Rel13 MTC UEs?

[0158] 4. How to determine the UE's CE / repetition level used for paging transmission?

[0159] 2. Discussion

[0160] In the current specification TS 36.304, a Paging Occasion (PO) is a subframe in which there may be a P-RNTI sent on the PDCCH addressed to a paging message. A radio frame contains one or more paging occasions. In case of DRX, the UE only needs to monitor one PO for each DRX cycle.

[0161] In the context of Rel-13 MTC, PO is no longer a subframe because repetition will be required. We propose the following definition of PO:

[0162] Recommendation 1: A Paging Occasion (PO) is (the start of) a subframe bundle in a specific subband, where:

[0163] - In case ePDCCH is needed for paging transmission, the UE monitors the repetitions of ePDCCH for paging message scheduling, or

[0164] - In case ePDCCH is not needed for paging transmission, the UE monitors the repetitions of PDSCH for paging messages.

[0165] There may be different POs on different sub-bands.

[0166] 2.1 Paging for system information changes

[0167] As we know, paging messages are also used to notify UEs in RRC_IDLE and UEs in RRC_CONNECTED of system information changes. The system information change paging is a 1-bit indicator and is sent along with other normal paging records (if present). In the event that any system information element is to be changed, the eNB must send this indicator on all POs for all UEs to ensure that all UEs will be notified in time.

[0168] In the context of Rel-13 MTC, system information modification for UEs in RRC-IDLE and RRC-CONNECTED modes is discussed separately:

[0169] System Information Changes for UEs in RRC-IDLE

[0170] Option 1: Send a page for system information modification along with a normal paging record (as a legacy)

[0171] With this option, the eNB has to send paging on all POs addressed to all types of Rel-13 MTC UEs as legacy. Due to hundreds of repetitions, the work of sending on all POs is much greater compared to legacy.

[0172] Option 2: Paging for system information modification is separate from normal paging

[0173] With this option, paging for system information must be sent in a common subband, and all UEs should work on this common subband and try to monitor the paging occasion for system information modification. This means that during the paging occasion for system modification, all Rel-13 MTC UEs cannot be scheduled in other subbands. In addition, from the UE's perspective, this will be additional paging monitoring work and result in greater power consumption.

[0174] Considering that the system information will be very little, option 1 is preferred:

[0175] Recommendation: Send the system information modification indicator along with the normal paging record.

[0176] System Information Changes for UEs in RRC_CONNECTED

[0177] Option 1: Notification of system information changes via (as traditional) paging

[0178] It is possible that a UE in RRC_CONNECTED mode is scheduled on a subband different from the subband used for monitoring paging. This will require the UE to re-tune to the subband used for paging and system information reading.

[0179] Option 2: Send new system information via dedicated signaling:

[0180] The UE can continue to operate on the subband of the unicast channel. If there are a large number of rel13UEs in RRC-CONNECTED, it will be very expensive to send the changed system information to each UE one by one. However, if there is an ongoing data transmission for the target UE, it will be less expensive by multiplexing the system information and data, assuming that only the changed part of the SI is sent to the UE.

[0181] Option 3: Release the RRC connection

[0182] If there is no ongoing data transmission for the UE, another possible option is to release the UE, whereupon the UE will read the system information via the broadcast channel.

[0183] Option 2 and Option 3 can be implemented by the eNB to work together. Considering that the UE in coverage enhancement is kept in RRC-CONNECTED mode only when there is ongoing data, the following suggestions are made:

[0184] Recommendation: Use dedicated signaling for system information changes for RRC-CONNECTED REL13 MTC UEs, i.e., RRC-CONNECTED REL13 MTC UEs are not required to monitor paging for system information modifications.

[0185] 2.2 Using or Not Using ePDCCH

[0186] Similar to system information transmission, a key question related to paging transmission is whether dynamic L1 scheduling information in ePDCCH is needed. Our pros and cons analysis is as follows:

[0187] Without using ePDCCH (i.e. without dynamic L1 scheduling information):

[0188] - Lack of scheduling flexibility: The radio resources, modulation order, and coding rate used for paging transmission cannot be changed dynamically.

[0189] - Fixed TBS / MCS and radio resources: A fixed number (eg, only 1) of UEs can be paged in one PO.

[0190] - Additional paging delay in case there is no space to accommodate all paging requests: When more UEs need to be paged, the eNB may delay paging to the next PO, which will cause scheduling delay.

[0191] - Paging capacity limitation due to fixed TBS. On the other hand, more POs can be configured to increase the paging capacity, however this will cause more UE power consumption to monitor more POs.

[0192] - Save resource usage of ePDCCH transmission.

[0193] Using ePDCCH (i.e., with dynamic L1 scheduling information)

[0194] - Greater scheduling flexibility: The radio resources, modulation order, and coding rate used for paging transmission can be changed dynamically.

[0195] -Changeable TBS / MCS and radio resources: The number of UEs paged in one PO is flexible.

[0196] - The paging capacity is adapted to the paging request.

[0197] - More radio resources for ePDCCH transmission.

[0198] - Twice the power consumption: For each PO, if ePDCCH is detected with P-RNTI (which is very likely), the UE must first monitor the ePDCCH bundle and then the PDSCH bundle. This means that there is a maximum of twice the power consumption due to the two-level paging monitoring of ePDCCH-PDSCH.

[0199] Compared with the "Do not use ePDCCH" option, the "Use ePDCCH" option has obvious flexibility in scheduling, paging capacity, and is more applicable. However, considering that ePDCCH repetition requires additional resources, it is not clear whether it is more resource efficient. In addition, from the UE's perspective, this will result in more wake-up time and increased power consumption. The compromise is to allow limited flexibility on the option "Do not use ePDCCH", such as to indicate / adjust the TB size of the paging message in the system information based on, for example, the MTC paging load of the cell.

[0200] Recommendation: RAN2 considers not having dynamic L1 scheduling information in ePDCCH, but indicating limited scheduling information, such as TBS in SI, for paging transmission.

[0201] 2.3 Separation or not

[0202] RAN1 agrees that paging messages for Rel-13 low complexity UEs and / or UEs operating with coverage enhancement (CE) are sent separately from paging messages for other UEs. It has not yet been confirmed whether paging messages for Rel-13 low complexity UEs operating with normal coverage and with different coverage enhancements (CE) are sent separately.

[0203] In the following discussion, LC Rel-13 MTC UEs in normal coverage are not specifically mentioned. Low complexity UEs in normal coverage can be considered as a special reception / CE level, such as CE level 0, because the UE location is unknown to the NW, and thus cell edge coverage is used when calculating the number of repartitions.

[0204] Separate case: Separate ePDCCH / PDSCH transmission is required for each CE level. In the case where there is one paging for UEs at CE level 1 and another paging for UEs at CE level 2, two ePDCCHs are required if there is an ePDCCH, or two PDSCHs are required if there is no ePDCCH. Due to the separate filling for different TBs, there may be more PDSCH load. Regarding system information modification, the eNB must send paging / paging scheduling on all POs corresponding to all repetition levels, and this also means more resource consumption. The UE and the network side should have strictly the same assumptions about the repetition level in all cases, otherwise it will cause misalignment between transmission and monitoring resources, and paging will always fail.

[0205] Case without separation: As shown in the figure, the number of repetitions should be the maximum value required for all paged UEs. In the case where there is one paging for a UE at CE level 1 that requires N repetitions and another paging for a UE at CE level 4 that requires M repetitions (where M>N), the eNB will send a paging message including two paging records for these two UEs with M repetitions. In the control implemented by the eNB, in the case where the number of repetitions between the paged UEs is too different and there are many paging requests, the UE can group the paging of UEs with the same CE level together and page different groups at different times at the cost of additional paging delay. From the UE's point of view, UEs of different CE levels attempt to combine ePDCCH / PDSCH on a sufficient number of subframes. Following the same example, a UE at CE level 1 attempts to decode a combination of N subframe ePDCCH / PDSCH, but a UE at CE level 4 attempts to decode a combination of M subframe ePDCCH / PDSCH to check whether the UE is paged. If there are only a few paging requests, it may be more resource efficient to multiplex the paging records even though they have very different repetition times. The resource consumption of paging for system information modification will be less.

[0206] If ePDCCH exists, for the "separate option", even if different ePDCCHs are needed for different CE levels, paging records addressed to different CE levels can still be multiplexed into one PDSCH / TB in a way that all ePDCCHs point to the same PDSCH.

[0207] Based on the above analysis, we prefer not to separate the paging transmissions for different types of Rel-13 MTC UEs.

[0208] Recommendation: Do not separate the paging transmission for different types of Rel-13 MTC UEs, ie the network may transmit paging records addressed to Rel-13 MTC UEs of different types / CE levels in one paging message.

[0209] 2.4 CE level determination

[0210] To determine the CE level of a UE in a specific cell, there are two options:

[0211] Option 1: Based on eNB [such as Fig. 9 [shown]

[0212] The eNB makes the final decision about which CE level the UE is at in a given cell, then informs the CN and may also inform the UE to reconcile what is known. This option enables more control on the eNB side. The same UE may have different CE / repetition levels in different cells, and in order to enable paging of UEs in more than one cell as is done today, the CE levels in all cells must be collected one by one based on the RACH procedure.

[0213] Option 2: Based on UE [such as Fig.10 [shown]

[0214] The UE measures the DL radio conditions of all detected cells and determines the CE level in each cell and then reports it to the CN, for example as part of capability reporting. The eNB has less control over this option and we must ensure that the UE will not abuse this information and report a higher CE level than necessary. The CE level in all paging cells can be measured and reported to the network at once.

[0215] Recommendation: RAN2 discusses whether CE level determination should be based on UE or eNB.

[0216] The whole or part of the exemplary embodiments disclosed above may be described as, but not limited to, the following supplementary descriptions.

[0217] (Supplementary Note 1) A base station for a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, and the base station comprises:

[0218] means for receiving a paging request for paging at least one MTC device from a core network entity;

[0219] means for determining a paging occasion at which the at least one MTC device will be sent paging related information, wherein the paging occasion identifies a plurality of subframes at which the paging related information will be first sent and then repeated; and

[0220] means for sending the paging related information in the plurality of subframes identified by the paging occasions and then repeating the paging related information.

[0221] (Supplementary Note 2) A base station according to Supplementary Note 1, wherein the paging-related information includes scheduling information identifying the time and / or frequency resources to be used to send a paging message to the at least one MTC device, and the multiple subframes identified by the paging occasions are subframes in which a control channel carrying the paging-related information is sent.

[0222] (Supplementary Note 3) The base station according to Supplementary Note 2, wherein the at least one MTC device includes at least one coverage enhanced MTC device having a first coverage enhancement level and at least one coverage enhanced MTC device having a second coverage enhancement level different from the first coverage enhancement level.

[0223] (Supplementary Note 4) A base station according to Supplementary Note 3, wherein the paging-related information includes: a first paging identifier (e.g., a wireless network temporary identifier) ​​for identifying paging-related information for at least one coverage-enhanced MTC device with a first coverage enhancement level; and a second paging identifier (e.g., a different wireless network temporary identifier) ​​for identifying paging-related information for at least one coverage-enhanced MTC device with a second coverage enhancement level.

[0224] (Supplementary Note 5) A base station according to Supplementary Note 3, wherein paging-related information for at least one coverage-enhanced MTC device with a first coverage enhancement level is first sent in a control channel within a first subframe, and paging-related information for at least one coverage-enhanced MTC device with a second coverage enhancement level is first sent in a control channel within a second subframe different from the first subframe.

[0225] (Supplementary Note 6) A base station according to Supplementary Note 3, wherein paging-related information for at least one coverage-enhanced MTC device with a first coverage enhancement level is sent in a control channel within at least one subframe, wherein in the at least one subframe, paging-related information for at least one coverage-enhanced MTC device with a second coverage enhancement level is also sent using the same control channel.

[0226] (Supplementary Note 7) The base station according to Supplementary Note 1, wherein the paging-related information includes at least one paging message for the at least one MTC device, and the multiple subframes identified by the paging occasion are subframes in which the at least one paging message is sent and then repeated.

[0227] (Supplementary Note 8) The base station according to Supplementary Note 7, wherein the base station further comprises a component for performing the following operation: sending scheduling information for identifying resources to be used for sending the at least one paging message to the at least one MTC device in a system information block.

[0228] (Supplementary Note 9) The base station according to Supplementary Note 8, wherein the scheduling information includes information identifying a transport block size (TBS) for the requested paging.

[0229] (Supplementary Note 10) A base station according to any one of Supplementary Notes 7 to 9, wherein the at least one MTC device includes at least one coverage-enhanced MTC device having a first coverage enhancement level and at least one coverage-enhanced MTC device having a second coverage enhancement level different from the first coverage enhancement level.

[0230] (Supplementary Note 11) A base station according to Supplementary Note 10, wherein a first predetermined frequency resource is used to send a paging message for the at least one coverage enhanced MTC device with a first coverage enhancement level, and a second predetermined frequency resource different from the first predetermined frequency resource is used to send a paging message for the at least one coverage enhanced MTC device with a second coverage enhancement level.

[0231] (Supplementary Note 12) A base station according to Supplementary Note 10, wherein a paging message for the at least one coverage enhanced MTC device with a first coverage enhancement level is first sent in a data channel within a first subframe, and a paging message for the at least one coverage enhanced MTC device with a second coverage enhancement level is first sent in a data channel within a second subframe different from the first subframe.

[0232] (Supplementary Note 13) A base station according to Supplementary Note 10, wherein a paging message for the at least one coverage enhanced MTC device with a first coverage enhancement level is sent in a data channel within at least one subframe, wherein in the at least one subframe, a paging message for the at least one coverage enhanced MTC device with a second coverage enhancement level is also sent in the same data channel.

[0233] (Supplementary Note 14) A base station according to any one of Supplementary Notes 1 to 9, wherein the at least one MTC device includes at least one coverage-enhanced MTC device, the base station further includes a component for identifying a coverage enhancement level associated with the at least one coverage-enhanced MTC device, and the component for sending the paging-related information and then repeating the paging-related information is configured to repeatedly send the paging-related information a number of repetitions defined by the coverage enhancement level.

[0234] (Supplementary Note 15) The base station according to Supplementary Note 14, wherein the paging request includes information identifying the coverage enhancement level, and the component for identifying the coverage enhancement level associated with the at least one coverage enhanced MTC device is configured to identify the coverage enhancement level based on the information identifying the coverage enhancement level in the paging request.

[0235] (Supplementary Note 16) A base station according to Supplementary Note 14, wherein the component for identifying the coverage enhancement level associated with the at least one coverage-enhanced MTC device is configured to identify the coverage enhancement level based on information obtained during a process for setting up a random access channel (RACH) with the at least one coverage-enhanced MTC device (e.g., a random access preamble code sequence index).

[0236] (Supplementary Note 17) A base station according to Supplementary Note 14, wherein, if the corresponding coverage enhancement level cannot be determined for the at least one coverage enhanced MTC device, the component for sending the paging-related information and then repeating the paging-related information is configured to repeat the paging-related information for a number of repetitions defined according to a predetermined (e.g., maximum and / or default) coverage enhancement level.

[0237] (Supplementary Note 18) A base station for a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, the base station comprising:

[0238] means for receiving a paging request for paging at least one MTC device from a core network entity;

[0239] means for determining a paging occasion at which the at least one MTC device is to be sent a paging message;

[0240] means for sending scheduling information identifying resources to be used for sending the paging message to the at least one MTC device in a system information block; and

[0241] means for sending the paging message to the at least one MTC device using the resources according to the paging occasion.

[0242] (Supplementary Note 19) A base station for a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, and the base station comprises:

[0243] means for receiving, from a core network entity, a paging request for paging at least one coverage enhanced MTC device;

[0244] means for identifying a coverage enhancement level associated with the at least one coverage enhanced MTC device; and

[0245] A means for sending paging related information and then repeatedly sending the paging related information for a number of repetitions defined by a coverage enhancement level.

[0246] (Supplementary Note 20) A base station for a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, and the base station comprises:

[0247] A component for determining that it is necessary to notify the MTC device that the system information has been changed, thereby generating modified system information;

[0248] means for notifying any MTC device in idle mode that the system information has changed by sending a notification using a paging message along with any paging records for the MTC device; and

[0249] Means for providing at least the modified portion of the modified system information to any MTC device in a radio resource control connected mode, ie, RRC connected mode, using MTC device-specific signaling (eg, unicast / dedicated RRC signaling).

[0250] (Supplementary Note 21) A machine type communication device, namely an MTC device, is used to communicate with a base station, the MTC device comprising:

[0251] a means for determining a paging occasion at which the base station can send paging related information, wherein the paging occasion identifies a plurality of subframes at which the base station will first send the paging related information and then repeat the paging related information; and

[0252] means for receiving the paging related information in the plurality of subframes identified by the paging occasions.

[0253] (Supplementary Note 22) A machine type communication device (MTC device) for use in a communication system, wherein in the communication system, the machine type communication device (MTC device) communicates via a base station, and the MTC device includes:

[0254] means for obtaining, from a system information block broadcasted by the base station, scheduling information for identifying resources to be used for sending at least one paging message;

[0255] A component for determining a paging occasion at which the base station can send a paging message for the MTC device;

[0256] means for determining the resources to be used for sending at least one paging message according to the scheduling information; and

[0257] means for receiving the paging message using the resources according to the paging occasion.

[0258] (Supplementary Note 23) A machine type communication device, namely an MTC device, used in a communication system, wherein in the communication system, the MTC device communicates via a base station, and the MTC device includes:

[0259] means for taking measurements to establish a measure of signal quality associated with at least one cell;

[0260] means for determining respective coverage enhancement levels associated with at least one cell based on said measure of signal quality associated with said at least one cell; and

[0261] Means for sending the respective coverage enhancement levels associated with the at least one cell to the base station.

[0262] (Supplementary Note 24) A machine type communication device, namely an MTC device, used in a communication system, wherein in the communication system, the MTC device communicates via a base station, and the MTC device includes:

[0263] A component for forming a radio resource control connection (RRC connection) with the base station to enter an RRC connection mode; and

[0264] A transceiver configured to obtain (at least a modified portion of) modified system information associated with a cell of the base station using dedicated signaling (eg, unicast / dedicated RRC signaling) while in the RRC connected mode.

[0265] (Supplementary Note 25) A core network node (e.g., a mobility management entity) used in a communication system, the core network node comprising:

[0266] means for obtaining information identifying a required coverage enhancement level in a cell of a base station for at least one coverage enhanced MTC device;

[0267] means for generating a paging request for paging the at least one coverage enhanced MTC device via the base station, wherein the paging request comprises information identifying the coverage enhancement level required in a cell of the base station for the at least one coverage enhanced MTC device; and

[0268] means for sending the paging request to the base station to page the at least one coverage enhanced MTC device in the cell according to the coverage enhancement level required in the cell.

[0269] (Supplementary Note 26) A system comprising the base station according to any one of Supplementary Notes 1 to 20, the MTC device according to any one of Supplementary Notes 21 to 24, and the core network node according to Supplementary Note 25.

[0270] (Supplementary Note 27) A method performed by a base station in a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, the method comprising the following steps:

[0271] receiving a paging request for paging at least one MTC device from a core network entity;

[0272] determining a paging occasion at which the at least one MTC device is to be sent paging related information, wherein the paging occasion identifies a plurality of subframes at which the paging related information is to be first sent and then repeated; and

[0273] The paging related information is sent in the multiple subframes identified by the paging occasion, and then the paging related information is repeated.

[0274] (Supplementary Note 28) A method performed by a base station used in a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, the method comprising the following steps:

[0275] receiving a paging request for paging at least one MTC device from a core network entity;

[0276] determining a paging occasion at which the at least one MTC device is to be sent a paging message;

[0277] Sending scheduling information for identifying resources to be used for sending the paging message to the at least one MTC device in a system information block; and

[0278] The paging message is sent to the at least one MTC device using the resource according to the paging occasion.

[0279] (Supplementary Note 29) A method performed by a base station used in a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, the method comprising the following steps:

[0280] receiving a paging request for paging at least one coverage enhanced MTC device from a core network entity;

[0281] identifying a coverage enhancement level associated with the at least one coverage enhanced MTC device; and

[0282] The paging related information is sent, and then the paging related information is repeatedly sent for a number of repetitions defined by the coverage enhancement level.

[0283] (Supplementary Note 30) A method performed by a base station used in a communication system, wherein in the communication system, a machine type communication device, i.e., an MTC device, communicates via the base station, the method comprising the following steps:

[0284] determining that it is necessary to notify the MTC device that the system information has changed, thereby generating modified system information;

[0285] notifying any MTC device in idle mode that the system information has changed by sending a notification using a paging message along with any paging records for the MTC device; and

[0286] At least the modified part of the modified system information is provided to any MTC device in a radio resource control connected mode, ie, RRC connected mode, using MTC device-specific signaling (eg, unicast / dedicated RRC signaling).

[0287] (Supplementary Note 31) A method performed by a machine type communication device, namely an MTC device, wherein the MTC device is used to communicate with a base station, the method comprising the following steps:

[0288] Determine a paging occasion at which the base station can send paging related information, wherein the paging occasion identifies a plurality of subframes at which the base station will first send the paging related information and then repeat the paging related information; and

[0289] The paging related information is received in the plurality of subframes identified by the paging occasion.

[0290] (Supplementary Note 32) A method performed by a machine type communication device (MTC device) in a communication system, wherein in the communication system, the machine type communication device (MTC device) communicates via a base station, the method comprising the following steps:

[0291] Obtaining scheduling information for identifying resources to be used for sending at least one paging message from a system information block broadcasted by the base station;

[0292] Determine a paging occasion at which the base station can send a paging message for the MTC device;

[0293] Determining the resource to be used for sending at least one paging message according to the scheduling information; and

[0294] The paging message is received using the resource according to the paging occasion.

[0295] (Supplementary Note 33) A method performed by a machine type communication device (MTC device) in a communication system, wherein the MTC device communicates via a base station in the communication system, the method comprising the following steps:

[0296] taking measurements to establish a measure of signal quality associated with at least one cell;

[0297] determining, based on the measure of signal quality associated with at least one cell, respective coverage enhancement levels associated with the at least one cell; and

[0298] The respective coverage enhancement levels associated with the at least one cell are sent to the base station.

[0299] (Supplementary Note 34) A method performed by a machine type communication device (MTC device) in a communication system, wherein the MTC device communicates via a base station in the communication system, the method comprising the following steps:

[0300] forming a radio resource control connection (RRC connection) with the base station to enter an RRC connection mode; and

[0301] While in the RRC connected mode, dedicated signaling (eg, unicast / dedicated RRC signaling) is used to obtain (at least a modified portion of) modified system information associated with a cell of the base station.

[0302] (Supplementary Note 35) A method performed by a core network node (e.g., a mobility management entity) used in a communication system, the method comprising the following steps:

[0303] obtaining information identifying a required coverage enhancement level in a cell of a base station for at least one coverage enhanced MTC device;

[0304] generating a paging request for paging the at least one coverage enhanced MTC device via the base station, wherein the paging request comprises information identifying the coverage enhancement level required in a cell of the base station for the at least one coverage enhanced MTC device; and

[0305] The paging request is sent to the base station according to the coverage enhancement level required in the cell to page the at least one coverage enhanced MTC device in the cell.

[0306] (Supplementary Note 36) A computer-implementable instruction product comprising computer-executable instructions, wherein the computer-implementable instructions are used to cause a programmable communication device to perform a method according to any one of Supplementary Notes 27 to 35.

[0307] This application is based upon and claims the benefit of priority from UK patent application 1506156.7 filed on April 10, 2015, the entire contents of which are incorporated herein by reference.

Claims

1. A machine type communication device, namely an MTC device, comprising: A memory for storing instructions; as well as at least one processor configured to process the instructions to: Establishing a radio resource control connection (RRC connection) with a base station to enter an RRC connection mode; as well as In a case where the MTC device is in the RRC connected mode and the MTC device has a subband without a common search space, a dedicated signaling message is received via the RRC connection, the dedicated signaling message including a change portion of system information including configuration information for paging the MTC device, the common search space being configured to monitor system information or paging.

2. A base station, comprising: A memory for storing instructions; as well as at least one processor configured to process the instructions to: Establishing a radio resource control connection (RRC connection) with a machine type communication device (MTC device) to enter an RRC connection mode; as well as In a case where the MTC device is in the RRC connected mode and the MTC device has a subband without a common search space, a dedicated signaling message is sent via the RRC connection, the dedicated signaling message including a change portion of system information including configuration information for paging the MTC device, the common search space being configured to monitor system information or paging.

3. A method performed by a machine type communication device, i.e., an MTC device, the method comprising: Establishing a radio resource control connection (RRC connection) with a base station to enter an RRC connection mode; as well as In a case where the MTC device is in the RRC connected mode and the MTC device has a subband without a common search space, a dedicated signaling message is received via the RRC connection, the dedicated signaling message including a change portion of system information including configuration information for paging the MTC device, the common search space being configured to monitor system information or paging.

4. A method performed by a base station, the method comprising: Establishing a radio resource control connection (RRC connection) with a machine type communication device (MTC device) to enter an RRC connection mode; as well as In a case where the MTC device is in the RRC connected mode and the MTC device has a subband without a common search space, a dedicated signaling message is sent via the RRC connection, the dedicated signaling message including a change portion of system information including configuration information for paging the MTC device, the common search space being configured to monitor system information or paging.

Images