NBIOT NPDCCH monitoring optimization in NTN

Abstract

A method and apparatus for monitoring NPDCCH in NBIoT are disclosed. A method includes receiving a first control signal for scheduling data transmission; and monitoring a second control signal from a start time slot to an end time slot, wherein the start time slot is a gap period behind the last time slot receiving the first control signal, and the end time slot is a time period ahead of the first time slot of data transmission.

Description

Technical Field

[0001] The subject matter disclosed herein relates generally to wireless communications, and more particularly to methods and apparatus for NBIoT NPDCCH listening optimization in non-terrestrial networks (NTNs). Background Art

[0002] The following abbreviations are defined herein, at least some of which are referred to in the following description: 3rd Generation Partnership Project (3GPP), New Radio (NR), European Telecommunications Standards Institute (ETSI), Frequency Division Duplex (FDD), Frequency Division Multiple Access (FDMA), Long Term Evolution (LTE), New Radio (NR), Very Large Scale Integration (VLSI), Random Access Memory (RAM), Read Only Memory (ROM), Erasable Programmable Read Only Memory (EPROM or Flash Memory), Compact Disc Read Only Memory (CD-ROM), Local Area Network (LAN), Wide Area Network (WAN), Personal Digital Assistant (PDA), User Equipment (UE), Uplink (UL), Evolved Node B (eNB), Next Generation Node B (gNB), Downlink (DL), Central Processing Unit (CPU), Graphics Processing Unit (GPU), Field Programmable Gate Array (FPGA), Dynamic RAM (DRAM), Synchronous Dynamic RAM (SDRAM), Static RAM (SRAM), Liquid Crystal Display (LCD), Light Emitting Diode (LED), Organic LED (OLED), Orthogonal Frequency Division Multiplexing (OFDM), Radio Resource Control , Time Division Duplex (RRC), Time Division Duplex (TDD), Time Division Multiplexing (TDM), User Entity / Equipment (Mobile Terminal) (UE), Uplink (UL), Universal Mobile Telecommunications System (UMTS), Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), Physical Downlink Control Channel (PDCCH), Downlink Control Information (DCI), Single DCI (S-DCI), Transmission Reception Point (TRP), Multiple TRPs (Multi-TRP or M-TRP), Frequency Range 2 (FR2), Quasi Co-location (QCL), Channel State Information Reference Signal (CSI-RS), CSI-RS Resource Indicator (CRI), Code Division Multiplexing (CDM), Transmission Configuration Indicator (TCI), Sounding Reference Signal (SRS), Control Resource Set (CORESET), Synchronization Signal (SS), Reference Signal (RS), Non-Terrestrial Network (NTN), Terrestrial Network (TN), Transport Block (TB), Internet of Things (IoT), Narrowband Internet of Things (NB-IoT or NBIoT), NBIoT PUSCH (NPUSCH), NBIoT PDCSH(NPDSCH), NBIoT PDCCH(NPDCCH), Machine Type Communication(MTC), MTCPDCCH(MPDCCH), Receiver and Transmitter Distance(RTD), Hybrid Automatic Repeat Request(HARQ), Geostationary Orbit(GEO), Low Earth Orbit(LEO).

[0003] For NBIoT, DCI format N0 (hereinafter referred to as DCI N0) is used to trigger NPUSCH format 1 uplink transmission. When the NBIoT UE receives DCI N0 on NPDCCH at time slot n (hereinafter referred to as subframe), it schedules NPUSCH format 1 uplink transmission at subframe n+k. When the maximum number of HARQ processes is equal to 2, the NBIoT UE has to monitor the second DCI N0 after receiving the first DCI N0.

[0004] like Figure 1 As shown, if the NBIoT UE detects an NPDCCH with DCI N0 (e.g., the first DCIN0) that ends in subframe n, and if the corresponding NPUSCH format 1 transmission starts from n+k, the UE is required to monitor NPDCCH candidates (for the second DCI N0) for the second DCI N0 in subframes starting from subframe n+1 to subframe n+k-3, and is not required to monitor NPDCCH candidates in subframes starting from subframe n+k-2 to subframe n+k-1.

[0005] Because the maximum number of HARQ processes is 2, the UE continues to monitor the NPDCCH for the next DCI N0 (i.e., the second DCI N0) from subframe n+1 to subframe n+k-3. However, since there should be 2 subframes (subframe n+k-2 and subframe n+k-1) for switching before NPUSCH transmission, the UE will not monitor the NPDCCH at these 2 subframes (subframe n+k-2 and subframe n+k-1).

[0006] The longer receiver and transmitter distance (RTD) in NTN has an impact on the timing relationship of NR (New Radio). It can introduce an offset K offset To modify the relevant timing relationship. For example, for the transmission timing of the DCI-scheduled PUSCH (including the CSI on the PUSCH), the time slot allocated for the PUSCH can be modified to For the transmission timing of PUSCH scheduled by RAR grant, UE is in time slot n+K2+Δ+K offset where the corresponding DCI transmits PUSCH in time slot n. K2 is the scheduling delay indicated in the DCI, and μ PUSCH and μ PDCCH It is a parameter corresponding to the subcarrier space related to PUSCH and PDCCH. For example, the subcarrier space of PUSCH is 15KHz, μ PUSCH is equal to 1, and the subcarrier space of PDCCH is 30KHz, μ PDCCH Equals 2.

[0007] For NBIoT in NTN, the timing offset K is directly introduced offsetAnd it is applied to modify the timing relationship (similar to NR NTN).

[0008] For example, Figure 2 As shown, for the transmission timing of NPUSCH scheduled by DCI in the NBIoT tradition, the UE transmits NPUSCH from subframe n+k0 (i.e., k=k0).

[0009] like Figure 2 As shown, the scheduling delay (k0) between the DCI (ie, DCI N0) and the corresponding NPUSCH (ie, NPUSCH format 1) is indicated by DCI N0. Specifically, the scheduling delay (k0) depends on the scheduling delay index (I Delay ) and the preconfigured maximum transmission repetition (R max ), that is, the maximum number of repetitions of the NPDCCH carrying DCI N0, as shown in Table 1 below. Scheduling Delay Index (I Delay ) is included in DCI N0. The maximum transmission repetition of the control signal (R max ) is preconfigured by higher layers.

[0010]

[0011] Table 1

[0012] On the other hand, Figure 3 As shown, for the transmission timing of NPUSCH scheduled by DCI in NBIoT in NTN, the UE can start from subframe n+k0+K offset (i.e., k=k0+K offset ) transmits NPUSCH. k0 is determined (or indicated) by DCI N0. offset Related to the round-trip distance between UE and eNB. K offset Can be configured in SIB or RRC signaling. If the UE has its own location information and earth orbit and ephemeris information, the UE can calculate the round trip delay from the eNB and the UE by itself. The earth orbit and ephemeris information indicate where the satellite is located. In other words, K offset Can alternatively be determined by the UE itself. offset The value of K can be determined by the satellite type. For example, if the eNB is in LEO, then K offset It can be tens of milliseconds, and if the eNB is on GEO, then K offset It could be several hundred milliseconds.

[0013] When the maximum number of HARQ processes for uplink transmission (NPUSCH format 1 transmission) is configured as 2 in NBIoT, when the scheduling delay between DCI and the corresponding NPUSCH is extended to k0+K offsetWhen k0+K is used, the UE will continue to monitor the NPDCCH for the next DCI in the following UE-specific search space (i.e., the delay period except the last two subframes before the NPUSCH transmission used for switching). However, due to the longer RTD in NTN, the delay k0+K offset Therefore, there may be unnecessary power consumption when monitoring the next DCI in the UE-specific search space.

[0014] The present disclosure aims to save power in UE-specific search space on NBIoT in NTN. Summary of the invention

[0015] Disclosed are a method and apparatus for monitoring NPDCCH in NBIoT.

[0016] In one embodiment, a method includes receiving a first control signal that schedules data transmission; and monitoring a second control signal from a start time slot to an end time slot, wherein the start time slot is a gap period behind the last time slot in which the first control signal is received, and the end time slot is a time period ahead of the first time slot of the data transmission.

[0017] In one embodiment, the gap period is configured by a broadcast signal. Alternatively, the gap period is determined by at least one of UE location information and corresponding satellite orbit and ephemeris information.

[0018] In another embodiment, the method further comprises skipping listening to the second control signal during a gap period, wherein a first time slot of the gap period immediately follows a last time slot in which the first control signal is received.

[0019] In some embodiments, the time period between the end time slot and the first time slot of the data transmission is two time slots.

[0020] In another embodiment, the remote unit includes a receiver configured to receive a first control signal that schedules data transmission; and a processor configured to listen for a second control signal from a start time slot to an end time slot, wherein the start time slot is one slot period behind the last time slot in which the first control signal is received, and the end time slot is one time period ahead of the first time slot of the data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the accompanying drawings. Understanding that these drawings depict only some embodiments and are therefore not to be considered limiting of scope, the embodiments will be described and explained with additional uniqueness and detail through the use of the accompanying drawings, in which:

[0022] Figure 1 The figure shows the traditional NPDCCH search space;

[0023] Figure 2 The figure shows the traditional NPDCCH search space;

[0024] Figure 3 Figure 1 shows an updated conventional NPDCCH search space;

[0025] Figure 4 Figure 1 shows monitoring of NPDCCH in an updated conventional NPDCCH search space;

[0026] Figure 5 FIG. 1 illustrates monitoring of NPDCCH according to an embodiment;

[0027] Figure 6 The diagram shows a situation in which the NPDCCH listening window is positioned at the end of the gap period;

[0028] Figure 7 The diagram shows a situation in which the NPDCCH listening window is positioned at the beginning of the gap period;

[0029] Figure 8 is a schematic flow chart illustrating an embodiment of a method; and

[0030] Fig. 9 is a schematic block diagram illustrating an apparatus according to one embodiment. DETAILED DESCRIPTION

[0031] As will be appreciated by those skilled in the art, certain aspects of the embodiments may be embodied as systems, devices, methods or program products. Therefore, the embodiments may take the form of a complete hardware embodiment, a complete software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects, which may be generally referred to herein as a "circuit", "module" or "system". In addition, the embodiments may take the form of a program product embodied in one or more computer-readable storage devices, which store machine-readable code, computer-readable code and / or program code, hereinafter referred to as "code". The storage device may be tangible, non-transitory and / or non-transmitting. The storage device may not embody a signal. In a certain embodiment, the storage device only uses a signal for accessing the code.

[0032] Some functional units described in this specification may be labeled as "modules" to more particularly emphasize their independent implementation. For example, a module may be implemented as a hardware circuit including custom very large scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors or other discrete components. A module may also be implemented in a programmable hardware device such as a field programmable gate array, programmable array logic, or a programmable logic device.

[0033] Modules may also be implemented in code and / or software for execution by various types of processors. An identification module of code may, for example, include one or more physical or logical blocks of executable code, which may, for example, be organized as objects, procedures, or functions. However, the executable files identifying the modules need not be physically located together, but may include different instructions stored in different locations, which, when logically joined together, comprise the module and implement the described purpose of the module.

[0034] In fact, the module of code can contain a single instruction or many instructions, and can even be distributed on several different code segments, in different programs and across several memory devices. Similarly, operating data can be identified and illustrated in this article in the module and can be embodied in any suitable form and organized in any suitable type of data structure. The operating data can be collected as a single data set, or can be distributed on different locations, including on different computer-readable storage devices. In the case where a module or parts of a module are implemented in software, the software part is stored on one or more computer-readable storage devices.

[0035] Any combination of one or more computer readable media may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing code. The storage device may be, for example, but not necessarily, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0036] A non-exhaustive list of more specific examples of storage devices would include the following: an electrical connection having one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0037] The code for performing the operations of the embodiments may include any number of lines and may be written in any combination of one or more programming languages ​​including object-oriented programming languages ​​such as Python, Ruby, Java, Smalltalk, C++, and conventional procedural programming languages ​​such as the "C" programming language, and / or machine languages ​​such as assembly languages. The code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the last scenario, the remote computer may be connected to the user's computer via any type of network including a local area network (LAN) or a wide area network (WAN), or a connection to an external computer may be made (e.g., via the Internet using an Internet service provider).

[0038] References to "one embodiment", "embodiment" or similar language throughout the specification mean that the specific features, structures or characteristics described together with the embodiment are included in at least one embodiment. Therefore, unless otherwise explicitly specified, the phrases "in one embodiment", "in an embodiment" and similar language throughout the specification may but do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments". Unless otherwise explicitly specified, the terms "including", "comprising", "having" and their variations mean "including but not limited to". Unless explicitly specified, an enumerated list of items does not imply that any or all of the items are mutually exclusive. Unless otherwise explicitly specified, the terms "a", "an" and "the" also mean "one or more".

[0039] In addition, the features, structures or characteristics of the various embodiments may be combined in any suitable manner. In the following description, many specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of the embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific details or using other methods, components, materials, etc. In other cases, known structures, materials or operations are not shown or described in detail to avoid confusing aspects of the embodiments.

[0040] Aspects of different embodiments are described below with reference to schematic flow charts and / or schematic block diagrams of methods, devices, systems, and program products according to embodiments. It will be understood that each frame of the schematic flow chart and / or schematic block diagram and the combination of frames in the schematic flow chart and / or schematic block diagram can be implemented by code. The code can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that instructions executed by a processor of a computer or other programmable data processing device create a device for implementing the functions specified for one or more frames in the schematic flow chart and / or schematic block diagram.

[0041] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other device to function in a specific manner so that the instructions stored in the storage device produce a product including instructions for implementing the functions specified in the blocks or some blocks of the schematic flowchart and / or schematic block diagram.

[0042] The code may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, so that the code executed on the computer or other programmable apparatus provides a process for implementing the functions specified in a box or some boxes of the flowchart and / or block diagram.

[0043] The schematic flow charts and / or schematic block diagrams in the figures illustrate the architecture, functionality and operation of possible implementations of the apparatus, system, method and program product according to various embodiments. In this regard, each box in the schematic flow charts and / or schematic block diagrams may represent a module, segment or portion of code, which includes one or more executable instructions of the code for implementing the specified (one or more) logical functions.

[0044] It should also be noted that in some alternative implementations, the functions annotated in the blocks may not occur in the order indicated in the figures. For example, two blocks shown in succession may be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order, depending on the functionality involved. Other steps and methods may be envisioned that are equivalent in function, logic, or effect to one or more blocks or portions thereof of the illustrated figures.

[0045] Although various arrow types and line types can be used in flow charts and / or block diagrams, they are understood not to limit the scope of the corresponding embodiments. In fact, some arrows or other connectors can be used to indicate the logical flow of only the depicted embodiments. For example, an arrow can indicate a waiting or listening period of unspecified duration between the enumeration steps of the depicted embodiments. It will also be noted that each frame of the block diagram and / or flow chart, and the combination of each frame in the block diagram and / or flow chart can be implemented by a combination of a dedicated hardware-based system or dedicated hardware and code that performs the specified function or behavior.

[0046] Descriptions of elements in various figures may refer to elements of previous figures. The same reference numerals refer to the same elements in all figures, including alternative embodiments of the same elements.

[0047] As mentioned in the background section, there may be unnecessary power consumption when monitoring the next DCI in the UE-specific search space. Figure 4 The figure shows that when the delay period is extended to k0+K offset Monitoring of NPDCCH during the test.

[0048] like Figure 4 As shown, after receiving the first DCI N0 ending in time slot n (hereinafter referred to as a subframe), the UE will start from subframe n+k0+K offset (i.e., k=k0+K offset ) starts the corresponding NPUSCH format 1 transmission. In addition, the UE continues from subframe n+1 to subframe n+k0+K offset -3 is the next DCI N0 (the second DCI N0) monitoring NPDCCH. UE in subframe n+k0+K offset -2 and subframe n+k0+K offset -1 does not monitor NPDCCH because these two frames are used to switch to NPUSCH transmission. k0 is determined by DCI N0. K offset Configured by broadcast signals, for example, in SIB or RRC signaling. When the UE has its location information and Earth orbit and ephemeris information, K offset It may alternatively be determined by the UE. The Earth orbit and ephemeris information indicate where the satellite is located.

[0049] Due to the longer RTD in NTN, the offset K offset It may be quite long. Therefore, from subframe n+1 to subframe n+k0+K offset It is a waste of power to monitor the NPDCCH for the second DCI N0 during the entire time period of -3.

[0050] Figure 5 The diagram shows the monitoring of NPDCCH according to an embodiment of the present application.

[0051] like Figure 5 As shown in FIG, the UE receives the first DCI N0 ending in subframe n. Then, the UE skips from subframe n+1 to subframe n+K. offset NPDCCH monitoring. UE starts from subframe n+K offset +1 to subframe n+K offset +k0-3 monitors the NPDCCH for the second DCI N0. The UE does not need to switch to NPUSCH transmission in the last two subframes, that is, subframe n+K offset +k0-2 and subframe n+K offset +k0-1——Monitor NPDCCH. UE starts from subframe n+K offset +k0 starts NPUSCH format 1 transmission indicated by the first DCI N0.

[0052] It can be seen that according to the present invention, if the NB-IoT UE detects an NPDCCH with DCI format N0 ending in subframe n, and if the corresponding NPUSCH format 1 transmission starts from n+k (i.e., n+K offset +k0), the UE does not need to be in the gap period, that is, from subframe n+1 to subframe n+K. offset The first subframe starts with the NPDCCH candidate, and the NPDCCH candidate is not required in the time period (for switching) - that is, from subframe n+K offset +k0-2 to subframe n+K offset +k0-1——Monitor NPDCCH candidates during the interval. The first subframe of the gap period, that is, subframe n+1, is immediately behind (that is, immediately after) the last subframe of receiving DCI format N0, that is, subframe n.

[0053] From another perspective, if the NB-IoT UE detects an NPDCCH with DCI format N0 ending in subframe n, and if the corresponding NPUSCH format 1 transmission starts in subframe n+k (i.e., n+K offset +k0), the UE starts from subframe n+K offset +1 to the end subframe n+K offset +k0-3 monitors NPDCCH candidates.

[0054] Start subframe - that is, subframe n+K offset +1 - lags behind the last subframe of the received DCI format N0 - that is, subframe n - by the gap period (from subframe n+1 to subframe n+K offset In other words, the gap period (from subframe n+1 to subframe n+K) offset) between the last subframe of the received DCI format N0, that is, subframe n, and the starting subframe, that is, subframe n+K offset +1——Between.

[0055] End subframe - that is, subframe n+K offset +k0-3 - in the first subframe used for NPUSCH format 1 transmission - that is, subframe n+K offset +k0——the previous two subframes. In other words, the two subframes used for switching (subframe n+K offset +k0-2 and subframe n+K offset +k0-1) at the end subframe (subframe n+K offset +k0-3) and the first subframe for NPUSCH format 1 transmission (subframe n+K offset +k0).

[0056] According to the present invention, for NBIoT in NTN with a maximum HARQ process number of 2, after receiving the first DCIN0, the UE will, after the gap period, for example, at K offset After the subframe, start monitoring the NPDCCH for the second DCI N0.

[0057] The gap period may be configured by a broadcast signal, for example, via SIB or higher layers. The gap period ranges from tens of milliseconds to hundreds of milliseconds. For example, if the eNB is on LEO, the gap period may be tens of milliseconds, while if the eNB is on GEO, the gap period may be hundreds of milliseconds. If the UE has its location information and earth orbit and ephemeris information, the gap period may be alternatively determined by the UE.

[0058] The NPDCCH search space is periodic. The length of the NPDCCH search space (i.e., NPDCCH time period) can be indicated as T = G·R max , where G is determined by a higher layer and R max is the maximum number of NPDCCH repetitions. The interstitial period can be expressed in units of NPDCCH time periods. For example, the interstitial period can be 10 NPDCCH time periods (i.e., 10T = 10G·R max ).

[0059] Figure 4 and Figure 5 The comparison between can indicate that according to the embodiment of the present invention ( Figure 5 )UE from subframe n+1 to subframe n+K offset Do not monitor the NPDCCH for the next DCI N0, but according to Figure 4 The prior art UE shown has to start from subframe n+1 to subframe n+K offsetTherefore, according to the embodiment of the present invention, it is possible to save the time from subframe n+1 to subframe n+K. offset Power consumption of monitoring.

[0060] According to the NPDCCH listening window of the present invention, that is, from Figure 5 From subframe n+K shown in offset +1 to subframe n+K offset +k0-3, which is positioned at the end of the gap period between the last subframe receiving DCI N0 and the corresponding NPUSCH transmission (in particular, 2 subframes before the NPUSCH transmission (for switching)), rather than at the beginning or in the middle of the gap period. The position of the NPDCCH listening window is selected from the perspective of facilitating scheduling, especially when the maximum number of HARQ processes is equal to 2.

[0061] Figure 6 The diagram shows a situation in which the NPDCCH listening window is positioned at the end of the gap period. Figure 7 Another scenario is illustrated in which the NPDCCH listening window is positioned at the beginning of the gap period (e.g., after the DCI).

[0062] like Figure 6 As shown in , the second DCI is monitored at the end of the gap period between the first DCI and the corresponding first NPUSCH; and the third DCI is monitored at the end of the gap period between the second DCI and the corresponding second NPUSCH. The scheduling proceeds smoothly.

[0063] On the other hand, Figure 7 As shown in , scheduling will be blocked by the limited number of (two) HARQ processes.

[0064] In general, if an NB-IoT UE detects an NPDCCH with DCI format N0 that ends in subframe n, and if the corresponding NPUSCH format 1 transmission starts in subframe n+k, the UE does not need to perform DCI operations from subframe n+1 to subframe n+K. offset and from subframe n+k-2 to subframe n+k-1 (assuming k=K offset+ k0) starts listening to NPDCCH candidates.

[0065] Figure 8 800 is a schematic flow chart illustrating an embodiment of a method 800 according to the present application. In some embodiments, the method 800 is performed by a device such as a remote unit. In some embodiments, the method 800 can be performed by a processor that executes program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, an FPGA, etc.

[0066] Method 800 may include 810 receiving a first control signal for scheduling data transmission; and 820 monitoring a second control signal from a start time slot to an end time slot, wherein the start time slot is one gap period behind the last time slot in which the first control signal is received, and the end time slot is one time period ahead of the first time slot for data transmission.

[0067] Fig. 9 is a schematic block diagram illustrating an apparatus according to one embodiment.

[0068] refer to Fig. 9 , UE (ie, remote unit) includes a processor, a memory and a transceiver. The processor is implemented in Figure 8 The functions, processes and / or methods proposed in the gNB (i.e., base station unit) include a processor, a memory and a transceiver. The layers of the radio interface protocol can be implemented by the processor. The memory is connected to the processor to store various information for driving the processor. The transceiver is connected to the processor to transmit and / or receive radio signals. Needless to say, the transceiver can be implemented as a transmitter for transmitting radio signals and a receiver for receiving radio signals.

[0069] The memory may be located inside or outside the processor and connected to the processor through various well-known means.

[0070] In the above-described embodiments, the components and features of the embodiments are combined in a predetermined form. Unless otherwise explicitly stated, each component or function should be considered as an option. Each component or feature can be implemented as not being associated with other components or features. In addition, the embodiments can be configured by associating some components and / or features. The order of the operations described in the embodiments can be changed. Some components or features of any embodiment can be included in another embodiment or replaced with components and features corresponding to another embodiment. It is obvious that claims that are not explicitly cited in the claims are combined to form embodiments or are included in new claims.

[0071] The embodiments may be implemented by hardware, firmware, software or a combination thereof. In the case of being implemented by hardware, according to the hardware implementation, the exemplary embodiments described herein may be implemented by using one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0072] Embodiments may be practiced in other specific forms. The described embodiments will be considered in all respects to be illustrative only and not restrictive. The scope of the present invention is therefore indicated by the appended claims rather than by the preceding description. All changes falling within the equivalent meaning and scope of the claims should be included within their scope.

Claims

1. A method performed by a remote unit, comprising: receiving a first control signal for scheduling data transmission; as well as monitoring a second control signal from a start time slot to an end time slot, wherein the start time slot lags behind the last time slot receiving the first control signal by a gap period, and the end time slot precedes the first time slot of the data transmission by a time period, The time period between the end time slot and the first time slot of the data transmission is two time slots.

2. The method according to claim 1, wherein: The gap period is configured by a broadcast signal.

3. The method according to claim 1, wherein: The gap period is determined by UE location information and at least one of corresponding satellite orbit and ephemeris information.

4. The method according to claim 1, further comprising: Listening to the second control signal is skipped during the gap period, wherein a first time slot of the gap period immediately follows the last time slot in which the first control signal is received.

5. A remote unit comprising: a receiver that receives a first control signal for scheduling data transmission; as well as a processor, wherein the processor monitors a second control signal from a start time slot to an end time slot, wherein the start time slot is a gap period behind the last time slot in which the first control signal is received, and the end time slot is a time period ahead of the first time slot of the data transmission, The time period between the end time slot and the first time slot of the data transmission is two time slots.

6. The remote unit of claim 5, wherein: The gap period is configured by a broadcast signal.

7. The remote unit of claim 5, wherein: The gap period is determined by UE location information and at least one of corresponding satellite orbit and ephemeris information.

8. The remote unit of claim 5, wherein: The processor skips listening to the second control signal during the gap period, wherein a first time slot of the gap period immediately follows the last time slot in which the first control signal is received.

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