CN111937478A

CN111937478A - Backup configuration in random access procedure

Info

Publication number: CN111937478A
Application number: CN201880092232.0A
Authority: CN
Inventors: 李海涛; R·拉塔素克
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Oyj
Priority date: 2018-04-05
Filing date: 2018-04-05
Publication date: 2020-11-13
Anticipated expiration: 2038-04-05
Also published as: WO2019192011A1; CN111937478B

Abstract

Embodiments of the present disclosure relate to a method, apparatus, and computer-readable storage medium for backup configuration in a Random Access (RA) procedure. In an example embodiment, a terminal device is configured with a first Coverage Enhancement (CE) mode. The terminal device initiates an RA procedure in a second CE mode different from the first CE mode. During a random access procedure, the terminal device determines whether a dedicated backup configuration is enabled. If it is determined that the dedicated backup configuration is enabled, the end device detects messages from the network device by using the dedicated backup configuration to make the RA procedure more efficient and effective.

Description

Backup configuration in random access procedure

Technical Field

Embodiments of the present disclosure relate generally to the field of communications, and, in particular, to a method, apparatus, and computer-readable storage medium for backup configuration in a Random Access (RA) procedure.

Background

In the third generation partnership project (3GPP) specifications, Coverage Enhancement (CE) levels have been proposed for User Equipment (UE) during Random Access (RA) to achieve enhanced coverage. For example, four CE levels are designated for different coverage areas. The UE may select a CE level from four CE levels for the CE levels based on a Reference Signal Received Power (RSRP) measurement of the serving cell and a broadcasted RSRP threshold. If the RA attempt at the selected CE level has failed several times, the UE may increase the CE level and initiate further RA attempts at the increased CE level until the maximum number of allowed attempts is reached.

For an RRC _ CONNECTED UE (RRC CONNECTED UE) in a Radio Resource Control (RRC) CONNECTED state, two CE modes are proposed, which are referred to as CE mode a and CE mode B, respectively. CE pattern a corresponds to CE level 0 and CE level 1 and specifies a set of behaviors with no or little repetition. CE pattern B corresponds to CE level 2 and CE level 3 and specifies another set of behaviors, which have a large number of repetitions. The specific CE mode may be explicitly configured to the UE via dedicated RRC signaling.

During the RA procedure for the RRC _ CONNECTED UE, the UE may also increase the CE level after an RA attempt at a lower CE level fails. The increase in CE level may span different CE modes. For example, if an RA attempt in CE mode a fails, the UE may switch to CE level 2 or 3 for CE mode B to initiate another RA attempt.

Disclosure of Invention

In general, example embodiments of the present disclosure provide a method, apparatus, and computer-readable storage medium for backup configuration in an RA procedure.

In a first aspect, a method at a terminal device is provided. The terminal device is configured with a first CE mode. The terminal device initiates a random access procedure in a second CE mode different from the first CE mode. During a random access procedure, the terminal device determines whether a dedicated backup configuration is enabled. If it is determined that the dedicated backup configuration is enabled, the end device detects a message from the network device by using the dedicated backup configuration.

In a second aspect, an apparatus is provided that includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: initiating a random access procedure in a second CE mode different from the configured first CE mode; and during the random access procedure, determining whether the dedicated fallback configuration is enabled, and in response to determining that the dedicated fallback configuration is enabled, detecting a message from the network device by using the dedicated fallback configuration.

In a third aspect, a computer-readable storage medium having a computer program stored thereon is provided. The computer program, when executed by a processor, causes the processor to perform the method according to the first aspect.

It should be understood that this summary is not intended to identify key features or essential features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become readily apparent from the following description.

Drawings

Some example embodiments will now be described with reference to the accompanying drawings, in which:

fig. 1 illustrates an example interaction procedure between a terminal device and a network device in a conventional RA procedure;

FIG. 2 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

FIG. 3 illustrates a flow diagram of an example method according to some embodiments of the present disclosure; and

fig. 4 shows a simplified block diagram of a device suitable for implementing embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numbers refer to the same or similar elements.

Detailed Description

The principles of the present disclosure will now be described with reference to a few exemplary embodiments. It is understood that these embodiments are described for illustrative purposes only and are presented to aid those skilled in the art in understanding and enabling the present disclosure without placing any limitation on the scope of the present disclosure. The disclosure described herein may be implemented in various ways other than those described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard or protocol, such as Long Term Evolution (LTE), LTE-advanced (LTE-a), and 5G NR, and employs any suitable communication technology, including, for example, multiple-input multiple-output (MIMO), OFDM, Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), bluetooth, ZigBee, Machine Type Communication (MTC), eMBB, MTC, and urrllc technologies.

As used herein, the term "network device" refers to any suitable device on the network side of a communication network. The network device may comprise any suitable device in an access network of a communication network, including, for example, a Base Station (BS), a relay, an Access Point (AP), a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a gigabit NodeB (gnb), a remote radio module (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a low power node (such as a femto node, pico node, etc.). For discussion purposes, in some embodiments, an eNB is taken as an example of a network device.

As used herein, the term "terminal device" refers to a device that is capable of being configured, arranged and/or operable to communicate with a network device or another terminal device in a communication network. The communication may involve the transmission and/or reception of wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for the transmission of information over the air. In some embodiments, the terminal device may be configured to transmit and/or receive information without direct human interaction. For example, when triggered by an internal or external event, or in response to a request from the network side, the terminal device may transmit information to the network device on a predetermined schedule.

Examples of end devices include, but are not limited to, User Equipment (UE), such as a smart phone, a wireless enabled tablet, a laptop embedded device (LEE), a laptop installed device (LME), and/or a wireless Customer Premises Equipment (CPE). For purposes of discussion, some embodiments will be described below with reference to a UE as an example of a terminal device, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of this disclosure.

As used herein, the term "circuitry" may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog circuitry and/or digital circuitry); and

(b) a combination of hardware circuitry and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) and software/firmware, and (ii) any portion of hardware processor(s) with software (including digital signal processor(s), software, and memory(s) that work together to cause a device such as a mobile telephone or server to perform various functions); and

(c) hardware circuit(s) and/or processor(s), such as microprocessor(s) or a portion of microprocessor(s), that require software (e.g., firmware) for operation, but which may not be present when software is not required for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also encompasses implementations that are part of a hardware circuit or processor (or multiple processors) alone or in combination with software and/or firmware accompanying it (or them). The term circuitry also encompasses, for example and where applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "including" and its variants are to be read as open-ended terms, which mean "including, but not limited to". The term "based on" will be read as "based, at least in part, on". The terms "one embodiment" and "an embodiment" are to be read as "at least one embodiment". The term "another embodiment" will be read as "at least one other embodiment". Other definitions (explicit and implicit) may be included below.

As described above, two CE modes, CE mode a and CE mode B, have been proposed for RRC _ CONNECTED UEs. The UE may use one or more of the CE levels corresponding to the two CE modes during the RA procedure. For example, an enhanced machine type communication (eMTC) UE may attempt RA at several CE levels during a Radio Access Channel (RACH) procedure. If the UE is configured with CE mode a, the UE may initiate a RACH procedure, e.g., in CE mode a, after reaching a maximum number of scheduling requests (SR-MAX). When the UE fails RA in CE mode a, the UE may select CE level 2 or 3 corresponding to CE mode B to transmit an additional RA preamble.

Conventionally, during the RACH procedure, the UE may use a common configuration for a selected CE level, such as a Common Search Space (CSS) for a machine type communication physical downlink control channel (MPDCCH) search space. For contention resolution purposes, after message 3(Msg3) is successfully transmitted to the eNB, the UE configured with CE mode a falls back to a dedicated configuration for CE mode a, such as a user-specific search space (USS) for MPDCCH search space, for further communication.

Fig. 1 shows an example interaction process 100 between a UE and an eNB in a conventional RA procedure. In this example, the UE is configured with CE mode a. After the RA attempt in CE mode a has failed, the UE selects CE level 2 or CE level 3 corresponding to CE mode B. Then, as shown, the UE sends (105) a message 1(Msg1) containing the RA preamble to the eNB at the selected CE level 2 or CE level 3, and then the eNB sends (110) a message 2(Msg2) as a Random Access Response (RAR). Upon receiving the Msg2, the UE sends (115) a message 3(Msg3) with a cell radio network temporary identifier (C-RNTI).

In this example, the transmission of Msg3 failed. The UE performs retransmission of Msg3 (120). During the retransmission (120) of the Msg3, the eNB sends (120a) an Uplink (UL) grant scrambled by the temporary C-RNTI. The UE may detect the UL grant using CSS for CE mode B. Upon receiving the UL grant, the UE sends (120b) Msg3 to the eNB. After successful Msg3 transmission or retransmission, the eNB sends (125) UL grant scrambled by C-RNTI in MPDCCH. At this point, the UE falls back to CE mode a and detects the UL grant using the dedicated configuration for CE mode a. The UE then initiates (130) a transmission on a Physical Uplink Shared Channel (PUSCH) based on the UL grant.

The inventors found that different CE modes typically have different configurations, such as maximum repetition number (R-max) for MPDCCH/PUCCH/PUSCH/Physical Downlink Shared Channel (PDSCH). CE mode-a specific configuration is sometimes not robust for transmission in CE mode B. For example, in the RA procedure shown in fig. 1, MPDCCH transmission (125) and PUSCH transmission (130) may not be successful in poor coverage by the eNB, using dedicated configuration for CE mode a.

In this case, the UE may have to retransmit a Radio Link Control (RLC) Protocol Data Unit (PDU). Radio link failure will be declared after the maximum RLC retransmission times are eventually reached. This may result in wasted resources, data interruption, more power consumption, etc. Meanwhile, transmission of RRC reconfiguration messages may fail even when the eNB wants to reconfigure CE mode B to the UE, due to insufficient CE mode-a configuration in poor coverage.

Embodiments of the present disclosure provide an improved RA procedure for a terminal device. A terminal device configured with a CE mode initiates RA procedures in the other CE mode. During the RA procedure, the terminal device determines whether the dedicated backup configuration is enabled. If it is determined that the dedicated backup configuration is enabled, the end device detects a message from the network device by using the dedicated backup configuration.

In various embodiments of the present disclosure, a dedicated backup configuration may be used by the end device during the RA procedure, if desired. In this way, the terminal device can switch to the configuration mode more suitable for radio conditions in time without waiting for CE mode reconfiguration from the network side, making the RA procedure more efficient and effective. In addition, network resources and UE power may be saved by disabling improper CE mode configuration.

Fig. 2 illustrates an example communication network 200 in which embodiments of the present disclosure may be implemented. The network 200 includes a terminal device 210 and a network device 220. It should be understood that the number of network devices and terminal devices are shown for illustrative purposes only and do not present any limitations. Network 200 may include any suitable number of network devices and terminal devices.

The terminal device 210 may communicate with the network device 220 or with another terminal device (not shown) via the network device 220. The communication may utilize any suitable technology that already exists or will be developed in the future. In some embodiments, the terminal device 210 may be implemented by an eMTC UE that communicates with the network device 220 or via the network device 220 using MTC and/or eMTC technologies.

In various embodiments of the present disclosure, terminal device 120 is configured with a CE mode and a dedicated backup configuration. During an RA procedure initiated in the further CE mode, a dedicated backup configuration may be used by the terminal device 120 to improve the RA procedure.

Fig. 3 illustrates a flow diagram of an example method 300 in accordance with some embodiments of the present disclosure. The method 300 may be implemented at a terminal device 210 as shown in fig. 2. For discussion purposes, the method 300 will be described with reference to fig. 2.

At block 305, a terminal device 210 configured with a CE mode (referred to as a first CE mode) initiates a random access procedure in a different CE mode (referred to as a second CE mode). The first CE mode and the second CE mode may be implemented by any suitable CE mode. In some embodiments, the terminal device 210 is in an RRC connected state, and the first and second CE modes are CE mode a and CE mode B for the RRC connected state.

In some embodiments, prior to initiating the RA procedure at block 305, terminal device 210 may initiate the RA procedure in the first mode. After the RA procedure in the first mode has failed, the terminal device 210 may initiate the RA procedure in the second CE mode. In some other embodiments, the terminal device 210 may directly use the second CE mode to initiate the RA procedure. For example, in case the terminal device 220 is configured with CE mode a (as first CE mode), if the terminal device 220 moves to an area in poor coverage of the network device 220, the terminal device 220 may choose to initiate an RA procedure using CE mode B (as second CE mode).

At block 310, terminal device 210 determines whether a dedicated backup configuration is enabled. The dedicated backup configuration may be configured by network device 220, for example, before the RA procedure is initiated. For example, the dedicated backup configuration may be configured with RRC signaling or a separate RRC reconfiguration message along with the configuration or parameters related to the first CE mode. Furthermore, the dedicated backup configuration may be reconfigured.

The dedicated backup configuration may include any suitable parameters other than the parameters related to the first CE mode. In some embodiments, a dedicated backup configuration may be associated with the second CE mode. Accordingly, the parameter(s) in the dedicated backup configuration may be related to the second CE mode. For example, in embodiments where the first CE mode is CE mode a, the dedicated backup configuration may include one or more parameters related to CE mode B, including, for example, R-max, a G factor (which may be used with R-max to define USS), a Downlink Control Information (DCI) format indicating a format of the PDCCH, and so on.

In some embodiments, a dedicated backup configuration may be associated with one or more CE levels of the second CE mode. For example, a dedicated backup configuration may include multiple parameter sets. Each parameter set is associated with one of the CE levels. In embodiments where the second CE mode is CE mode B, the dedicated backup configuration may include two parameter sets for CE level 2 and CE level 3, respectively. In some other embodiments, there may be no such parameter partitioning in the dedicated backup configuration. The dedicated backup configuration includes only parameter sets for the second CE mode.

In some embodiments, in addition to the private backup configuration, the end device 210 may be configured with one or more public backup configurations related to the second CE mode. Once the terminal device 210 initiates an RA attempt in the second CE mode, a common fallback configuration may be used, which will be discussed in detail in the following paragraphs.

Terminal device 210 may determine whether to enable the dedicated backup configuration by considering any suitable factors. In some embodiments, if some RA attempts in the first CE mode (referred to as a first set of RA attempts) have failed, the terminal device 210 may initiate further RA attempts in the second CE mode (referred to as a second set of RA attempts). After initiating the second set of RA attempts, terminal device 210 may determine that the dedicated backup configuration is enabled.

As another example, in embodiments where the dedicated fallback configuration includes a set of parameters for a CE level associated with the second CE mode, once the second set of RA attempts is initiated at the CE level, the terminal device 210 may determine that the set of parameters corresponding to the selected CE level is enabled.

Other events may also trigger the enablement of the dedicated backup configuration. For example, during a handoff of the terminal device 210 from the network device 220 to another network device (not shown), it may be determined that the dedicated backup configuration is enabled. As another example, the terminal device 210 may determine the enablement of the dedicated fallback configuration if the measured or reported RSRP level is below a threshold.

The enablement of the dedicated fallback configuration may also be triggered based on UE mobility. For example, if the terminal device 210 moves to an area in poor coverage of the network device 220, the terminal device 210 may determine that a dedicated backup configuration should be enabled. Additionally or alternatively, the terminal device 210 may determine the enablement of the dedicated backup configuration based on the cell deployment. For example, in a cell in poor coverage, the terminal device 210 may determine the enablement of the dedicated backup configuration.

In some embodiments, the associated timer may be configured for a dedicated backup configuration. Terminal device 210 may obtain the dedicated backup configuration and associated timer from network device 220 together. In this case, the terminal device 210 may determine whether to enable the dedicated backup configuration based on a timer. If the timer expires, terminal device 210 may determine that the dedicated backup configuration is disabled. In this way, the real-time nature of the configuration can be further guaranteed, and thus the success probability of the RA procedure can be further improved.

In block 315, after determining that the dedicated backup configuration is enabled, the terminal device 210 detects a message from the network device 220 using the dedicated backup configuration. The message may comprise any suitable message during the RA procedure. In some embodiments, the message may include an uplink grant from the network device 220.

In some embodiments, a dedicated backup configuration may be used to detect messages after successful transmission of Msg 3. For example, after a successful transmission or retransmission of Msg3 in the second CE mode, the terminal device 210 may start using/activating the dedicated backup configuration. The terminal device 210 may then use the dedicated backup configuration to detect the UL grant from the network device 220. During the Msg3 retransmission, the terminal device 210 may still monitor the CSS for MPDCCH scrambled with a temporary C-RNTI, e.g., specified by the second CE mode and broadcast by the network device 220. In these embodiments, the terminal device 210 may use the common configuration specified by the second CE mode before the Msg3 transmission or retransmission is successful.

In embodiments where the dedicated fallback configuration is associated with the second CE mode and the terminal device 210 initiates the second set of RA attempts in the second CE mode, the dedicated fallback configuration may be triggered after initiation of the second set of RA attempts. For example, the terminal device 210 may switch to the second CE mode anonymously or implicitly. In some embodiments, the end device 210 may use the common configuration for the second CE mode before the Msg3 transmission or retransmission is successful and further communication using the dedicated backup configuration. Alternatively, in embodiments where a common backup configuration is also configured, terminal device 210 may use the common backup configuration after initiation of the second RA attempt.

In some embodiments, terminal device 210 may disable the dedicated backup configuration based on an indication that the dedicated backup configuration is disabled. The indication may include an indication from the network device 220, such as an indication for CE mode configuration or reconfiguration. For example, where terminal device 210 is configured with CE mode a, if terminal device 210 receives an indication from network device 220 to reconfigure CE mode B, terminal device 210 may disable the dedicated backup configuration and begin using the configured CE mode-B related parameters. As another example, terminal device 210 may also disable the dedicated backup configuration if network device 220 reconfigures some CE mode-a parameters to terminal device 210.

In embodiments where the dedicated fallback configuration is associated with a timer, the indication to disable the dedicated fallback configuration may be an indication that the associated timer has expired. Terminal device 210 may disable the dedicated backup configuration after expiration of the timer.

In some embodiments, terminal device 210 may continue to use the dedicated backup configuration in response to an indication of CE mode configuration or reconfiguration. For example, in embodiments where the dedicated backup configuration is associated with the second CE mode, if network device 220 instructs terminal device 210 to switch to the second CE mode, terminal device 210 may continue to use the dedicated backup configuration while using the common configuration for the second CE mode.

In some embodiments, the terminal device 210 may automatically trigger a radio link failure and re-establishment after a failure of the RA procedure in the first CE mode. In this case, the first CE mode configuration may be refreshed before the terminal device 210 accesses the re-established cell.

In some embodiments, an apparatus (e.g., terminal device 210) capable of performing method 300 may include means for performing the respective steps of method 300. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules.

In some embodiments, the apparatus comprises: means for initiating a random access procedure in a second Coverage Enhancement (CE) mode different from a configured first CE mode; means for determining whether a dedicated fallback configuration is enabled during a random access procedure; and means for detecting a message from the network device using the dedicated backup configuration in response to determining that the dedicated backup configuration is enabled.

In some embodiments, the means for initiating comprises: means for initiating a second set of random access attempts in a second CE mode in response to a first set of random access attempts in the first CE mode having failed.

In some embodiments, a dedicated backup configuration is associated with the second CE mode. The means for determining includes: means for determining that the dedicated fallback configuration is enabled in response to the initiation of the second set of random access attempts.

In some embodiments, the second CE mode is associated with a CE level, and the dedicated fallback configuration comprises a set of parameters for the CE level. The means for initiating the second set of random access attempts comprises means for initiating the second set of random access attempts at the CE level. The means for determining comprises means for determining that the set of parameters is enabled in response to initiating the second set of random access attempts at the CE level.

In some embodiments, the apparatus further comprises: means for continuing to further communicate with the network device using the dedicated backup configuration in response to receiving the indication to switch the first CE mode to the second CE mode.

In some embodiments, a dedicated backup configuration is associated with the timer. The means for determining includes: means for determining that the dedicated backup configuration is disabled in response to expiration of the timer.

In some embodiments, the message includes an uplink grant from the network device. The means for detecting comprises: means for detecting an uplink grant from the network device in response to successful transmission of message 3 by using the dedicated backup configuration.

In some embodiments, the apparatus further comprises: means for receiving a dedicated backup configuration in Radio Resource Control (RRC) signaling from a network device prior to initiating a random access procedure.

In some embodiments, the apparatus further comprises: means for disabling the dedicated backup configuration in response to an indication that the dedicated backup configuration is disabled.

Fig. 4 is a simplified block diagram of an apparatus 400 suitable for implementing embodiments of the present disclosure. Device 400 may be implemented at, or at least partially as part of, terminal device 210 as shown in fig. 2.

As shown, the device 400 includes a processor 410, a memory 420 coupled to the processor 410, a communication module 440 coupled to the processor 410, and a communication interface (not shown) coupled to the communication module 440. The memory 410 stores at least a program 430. The communication module 440 is for bi-directional communication. The communication interface may represent any interface required for communication with a network element, such as the Uu interface for communication between the eNB and the UE.

The program 430 is assumed to include program instructions that, when executed by the associated processor 410, enable the device 400 to operate in accordance with embodiments of the present disclosure, as discussed herein with reference to fig. 2-3. Embodiments herein may be implemented by: the processor 410 of the device 400 may execute computer software, or hardware, or a combination of software and hardware. The processor 410 may be configured to implement various embodiments of the present disclosure.

The memory 410 may be of any type suitable to a local technology network and may be implemented using any suitable data storage technology, such as non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. Although only one memory 410 is shown in device 400, there may be several memory modules in device 400 that are physically different. The processor 410 may be of any type suitable for a local technology network, and may include one or more of the following, as non-limiting examples: general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs) and processors based on a multi-core processor architecture. The device 400 may have multiple processors, such as an application specific integrated circuit chip that is time dependent from a clock synchronized with the main processor.

In general, the various embodiments of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented as non-limiting examples in the following: hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product comprises computer-executable instructions, such as those included in program modules, that are executed in the device on the target real or virtual processor to perform the method 300 as described above with reference to fig. 2-3. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or divided between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local device or within a distributed device. In a distributed facility, program modules may be located in both local and remote memory storage media.

Program code for performing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowchart and/or block diagram to be performed. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method, comprising:

at a terminal device configured with a first Coverage Enhancement (CE) mode:

initiating a random access procedure in a second CE mode different from the first CE mode; and

during the random access procedure:

determining whether a dedicated backup configuration is enabled, an

In response to determining that the dedicated backup configuration is enabled, detecting a message from a network device using the dedicated backup configuration.

2. The method of claim 1, wherein initiating the random access procedure comprises:

initiating a second set of random access attempts in the second CE mode in response to a first set of random access attempts in the first CE mode having failed.

3. The method of claim 2, wherein the dedicated backup configuration is associated with the second CE mode, and determining whether the dedicated backup configuration is enabled comprises:

determining that the dedicated fallback configuration is enabled in response to the initiation of the second set of random access attempts.

4. The method of claim 3, wherein the second CE mode is associated with a CE level and the dedicated fallback configuration comprises a set of parameters for the CE level,

wherein initiating the second set of random access attempts comprises initiating the second set of random access attempts at the CE level, and

wherein determining that the dedicated backup configuration is enabled comprises: determining that the set of parameters is enabled in response to initiating the second set of random access attempts at the CE level.

5. The method of any of claims 1 to 4, further comprising:

in response to receiving an indication to switch the first CE mode to the second CE mode, continue to use the dedicated fallback configuration for further communication with the network device.

6. The method of any of claims 1-5, wherein the dedicated backup configuration is associated with a timer, and determining whether the dedicated backup configuration is enabled comprises:

determining that the dedicated backup configuration is disabled in response to expiration of the timer.

7. The method of any of claims 1-6, wherein the message comprises an uplink grant from the network device, and detecting the message from the network device comprises:

detecting the uplink grant from the network device by using the dedicated backup configuration in response to successful transmission of message 3.

8. The method of any of claims 1 to 7, further comprising:

receiving the dedicated backup configuration in Radio Resource Control (RRC) signaling from the network device prior to the initiation of the random access procedure.

9. The method of any of claims 1 to 8, further comprising:

disabling the dedicated backup configuration in response to an indication that the dedicated backup configuration is disabled.

10. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to:

initiating a random access procedure in a second Coverage Enhancement (CE) mode different from the configured first CE mode; and

during the random access procedure:

determining whether a dedicated backup configuration is enabled, an

11. The apparatus of claim 10, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

initiating a second random access attempt in the second CE mode in response to a first random access attempt in the first CE mode having failed.

12. The apparatus of claim 11, wherein the dedicated backup configuration is associated with the second CE mode, and the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

determining that the dedicated fallback configuration is enabled in response to the initiation of the second random access attempt.

13. The apparatus of claim 12, wherein the second CE mode is associated with a CE level, and the dedicated fallback configuration comprises a set of parameters for the CE level; and is

Wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

initiating a second random access attempt at the CE level, an

Determining that the set of parameters is enabled in response to initiating the second random access attempt at the CE level.

14. The apparatus of any of claims 10 to 13, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to:

15. The apparatus of any of claims 10 to 14, wherein the dedicated backup configuration is associated with a timer, and the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

16. The apparatus of any of claims 10 to 15, wherein the message comprises an uplink grant from the network device, and the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:

17. The apparatus of any of claims 10 to 16, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to:

receiving the dedicated backup configuration in Radio Resource Control (RRC) signaling from the network device prior to the random access procedure.

18. The apparatus of any of claims 10-17, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to:

19. A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, causes the processor to carry out the method according to any one of claims 1 to 9.