A method and device for improving energy saving of an Internet of Things radio system

Abstract

A method includes performing, by a terminal device, sub-bandwidth portion-based operation. The method includes determining a requirement for radio frequency retuning and switching from sub-bandwidth portion-based operation to bandwidth portion-based operation. The method also includes performing bandwidth portion-based operation.

Description

Technical Field

[0001] Teachings according to example embodiments relate generally to power efficiency improvements for various applications (eg, smart phones) operating in specific scenarios, and particularly to radio systems, eg, with particular focus on machine type communications (MTC) / Internet of Things (IoT). Background Art

[0002] Machine-like terminals using MTC, including, for example, surveillance cameras, vending machines, smart meters, human sensors, IoT, etc., are envisioned to create a large amount of traffic for further cellular networks. The main requirements for MTC are low power consumption and low device prices. Compared to typical mobile phones / smartphones, the requirements for low power consumption are generally more critical for MTC devices. This is because the battery of a mobile phone can be easily charged (e.g., recharged), while this is generally not the case for MTC devices. For some types of MTC devices, even with clock-sized batteries, a lifetime of one or several years is required. On the other hand, the low price may require that the MTC device may have limited transceiver and receiver capabilities (compared to other devices).

[0003] The main requirement of 5G MTD (machine type device) is that the device can consume or generate any amount of data in a short time frame, the device may require millisecond reaction time (or latency), and the device may sleep for months, sending a byte from time to time. MTC-specific radio technologies include, for example, ZigBee, Bluetooth 4.0, low-power WiFi, 802.11ah, and IEEE802.15.4x. However, cellular MTC has the following advantages: for example, ubiquitous coverage and global connectivity, better QoS due to licensed spectrum and free (e.g., existing) signals that can be used for synchronization.

[0004] Certain abbreviations in this specification and / or drawings are defined as follows:

[0005] BWP Bandwidth Part

[0006] CORESET Control Resource Set

[0007] CP Cyclic Prefix

[0008] DCI Downlink Control Information

[0009] DL Downlink

[0010] DMRS Demodulation Reference Signal

[0011] DRX Discontinuous Reception

[0012] eNB Enhanced Node-B

[0013] FDM Frequency Division Multiplexing

[0014] FDMA Frequency Division Multiple Access

[0015] FFT Fast Fourier Transform

[0016] gNB 5G enhanced Node B (base station)

[0017] IOT Internet of Things

[0018] L3 Layer 3

[0019] LTE Long Term Evolution

[0020] MCS Modulation Coding Scheme

[0021] MIMO Multiple Input Multiple Output

[0022] MTC Machine Type Communication

[0023] MTD Machine Type Device

[0024] MU-MIMO Multi-User MIMO

[0025] NB Narrowband

[0026] NB-IoT Narrowband Internet of Things

[0027] NR New Radio

[0028] NZP Non Zero Power

[0029] OCC Orthogonal Cover Code

[0030] OFDM Orthogonal Frequency Division Multiplexing

[0031] OPEX Operating Expenditure

[0032] PBCH Physical Broadcast Channel

[0033] PDCCH Physical Downlink Control Channel

[0034] PRACH Physical Random Access Channel

[0035] PRB Physical Resource Block

[0036] PRS Positioning Reference Signal

[0037] PSS Primary Synchronization Signal

[0038] PUSCH Physical Uplink Shared Channel

[0039] QoS Quality of Service

[0040] RAN4 3GPP RAN working group responsible for radio frequency

[0041] Rel version

[0042] RNTI Radio Network Temporary Identifier

[0043] SC-FDMA Single Carrier FDMA

[0044] SCS Subcarrier Spacing

[0045] SRS Sounding Reference Signal

[0046] SSB Synchronous Signal Block

[0047] SSBI Synchronous Signal Block Index

[0048] SSS Secondary synchronization signal

[0049] SU-MIMO Single User MIMO

[0050] TA Timing Advance

[0051] TRS Tracking Reference Signal

[0052] UE User Equipment

[0053] UL Uplink

[0054] 3GPP Third Generation Partnership Project Summary of the invention

[0055] The following summary includes examples and is intended as examples only. The summary is not intended to limit the scope of the claims.

[0056] According to one aspect, an example method includes performing, by a terminal device, sub-bandwidth portion-based operation. The method includes determining a requirement for radio frequency retuning and switching from the sub-bandwidth portion-based operation to bandwidth portion-based operation. The method also includes performing bandwidth portion-based operation.

[0057] According to another aspect, an example apparatus includes: means for performing sub-bandwidth portion-based operation; means for determining a requirement for radio frequency retuning; means for switching from sub-bandwidth portion-based operation to bandwidth portion-based operation; and means for performing bandwidth portion-based operation.

[0058] According to another aspect, an example apparatus includes at least one processor and at least one non-volatile memory including computer program code, wherein the at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to: perform sub-bandwidth portion-based operations; determine a requirement for radio frequency retuning; switch from sub-bandwidth portion-based operations to bandwidth portion-based operations; and perform bandwidth portion-based operations.

[0059] According to another aspect, an example apparatus includes a non-volatile program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine for performing operations, the operations comprising: performing sub-bandwidth portion-based operations by a terminal device; determining a requirement for radio frequency retuning; switching from the sub-bandwidth portion-based operations to bandwidth portion-based operations; and performing the bandwidth portion-based operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The foregoing and other aspects of embodiments of the present invention will become more apparent in the following detailed description when read in conjunction with the accompanying drawings, in which:

[0061] Figure 1 is a block diagram of one possible and non-limiting example system in which example embodiments may be implemented;

[0062] Figure 2 An example table showing radio system numerology options;

[0063] Figure 3 An example table showing maximum channel bandwidth according to subcarrier spacing and FFT size;

[0064] Figure 4 Example embodiments of different operation modes defined for NB-IoT are shown;

[0065] Figure 5 shows an example table with bandwidths of different signals for different radio system parameter sets;

[0066] Figure 6 An example embodiment of a DL BWP scenario is shown;

[0067] Figure 7 An example BWP adaptation is shown;

[0068] Figure 8 An example embodiment showing different UL BWP configurations in frequency / time; and

[0069] Fig. 9 A flow chart of a method executable by an apparatus according to an example embodiment is shown. DETAILED DESCRIPTION

[0070] In example embodiments as described herein, a method and apparatus are provided to provide energy-saving improvements for (e.g., NR) IoT networks. Example embodiments provide a cellular-based MTC framework with the goal of maximizing battery life and minimizing overhead for cellular systems. Example embodiments provide support for radio access technologies (e.g., 5G) for a variety of data application sets.

[0071] Go to Figure 1 , which shows a block diagram of one possible and non-limiting example system in which example embodiments may be implemented. A user equipment (UE) 110, a radio access network (RAN) node 170, and a network element 190 are shown. Figure 1 In the embodiment, a user equipment (UE) 110 performs wireless communication with a wireless network 100. A UE is a wireless device that can access a wireless network, typically a mobile device. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be an address bus, a data bus, or a control bus, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, an optical fiber or other optical communication device, etc. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a signaling module 140, which includes one or both of components 140-1 and / or 140-2 that can be implemented in a variety of ways. The signaling module 140 may be implemented in hardware as a signaling module 140-1, for example, as part of one or more processors 120. The signaling module 140-1 may also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the signaling module 140 may be implemented as a signaling module 140-2, which is implemented as a computer program code 123 that may be executed by one or more processors 120. For example, one or more memories 125 and the computer program code 123 may be configured to perform one or more operations as described herein with the one or more processors 120 using the user equipment 110. The UE 110 communicates with the RAN node 170 via a wireless link 111.

[0072] The RAN node 170 is a base station that provides access to the wireless network 100 for wireless devices such as UE 110. The RAN node 170 may be, for example, a base station for 5G, also known as New Radio (NR). In 5G, the RAN node 170 may be an NG-RAN node defined as a gNB or ng-eNB. The gNB is a node that provides NR user plane and control plane protocol termination to the UE and is connected to the 5GC (e.g., network element 190) via an NG interface. The ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination to the UE and is connected to the 5GC via an NG interface. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and a distributed unit (DU) (gNB-DU), where DU 195 is shown. Note that the DU may include a radio unit (RU) or be coupled to and control the RU. The gNB-CU is a logical node that hosts the RRC, SDAP, and PDCP protocols of the gNB or the RRC and PDCP protocols of the en-gNB, and controls the operation of one or more gNB-DUs. The gNB-CU terminates the F1 interface connected to the gNB-DU. The F1 interface is shown as reference numeral 198, but reference numeral 198 also shows the link between the remote elements of the RAN node 170 and the central elements of the RAN node 170, such as the link between the gNB-CU 196 and the gNB-DU 195. The gNB-DU is a logical node that hosts the RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partially controlled by the gNB-CU. One gNB-CU supports one or more units. A unit is supported by only one gNB-DU. The gNB-DU terminates the F1 interface 198 connected to the gNB-CU. Note that the DU 195 is considered to include the transceiver 160, such as part of the RU, but some examples thereof may include the transceiver 160 as part of a separate RU, such as under the control of the DU 195 and connected to the DU 195. The RAN node 170 may also be an eNB (evolved NodeB) base station for LTE (Long Term Evolution), or any other suitable base station.

[0073] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / WI / F) 161, and one or more transceivers 160 interconnected by one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include a processor 152, a memory 155, and a network interface 161. Note that the DU 195 may also contain its own memory and processor and / or other hardware, but these are not shown.

[0074] The RAN node 170 includes a control module 150, which includes one or both of components 150-1 and / or 150-2 that can be implemented in a variety of ways. The control module 150 can be implemented in hardware as the control module 150-1, for example, as part of one or more processors 152. The control module 150-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the control module 150 can be implemented as a control module 150-2, which is implemented as a computer program code 153 and is executed by one or more processors 152. For example, one or more memories 155 and the computer program code 153 are configured to, together with the one or more processors 152, cause the RAN node 170 to perform one or more operations as described herein. Note that the functionality of the control module 150 can be distributed, for example, between the DU 195 and the CU 196, or implemented only in the DU 195.

[0075] One or more network interfaces 161 communicate on the network, for example, via links 176 and 131. Two or more gNBs 170 communicate using, for example, link 176. Link 176 may be wired or wireless or both, and may implement, for example, an Xn interface for 5G, an X1 interface for LTE, or other suitable interfaces for other standards.

[0076] The one or more buses 157 may be an address bus, a data bus, or a control bus, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, an optical fiber or other optical communication device, a wireless channel, etc. For example, one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for a gNB implementation for 5G, other elements of the RAN node 170 may be physically located at a different location from the RRH / DU, and the one or more buses 157 may be partially implemented as, for example, a fiber optic cable or other suitable network connection to connect other elements of the RAN node 170 (e.g., a central unit (CU), gNB-CU) to the RRH / DU 195. Reference numeral 198 also shows these suitable network links. The RAN node 170 may be implemented by an IAB node. For example, the DU portion of the IAB node may facilitate gNB functionality, wherein the MT portion of the IAB node facilitates a backhaul connection to another IAB node or the RAN node 170.

[0077] The wireless network 100 may include a network element 190, which may include core network functions and provide a connection to another network, such as a telephone network and / or a data communication network (e.g., the Internet), via a link 181. Such core network functions for 5G may include access and mobility management functions (AMF) and / or user plane functions (UPF) and / or session management functions (SMF). Such core network functions for LTE may include MME (mobility management entity) / SGW (serving gateway) functions. These are merely example functions that may be supported by the network element 190, and it is noted that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network element 190 via a link 131. The link 131 may be implemented as, for example, an NG interface for 5G, an S1 interface for LTE, or other suitable interfaces for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / WI / F) 180 interconnected by one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, together with the one or more processors 175, cause the network element 190 to perform one or more operations.

[0078] Wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functions into a single, software-based managed entity, a virtual network. Network virtualization involves platform virtualization, often in conjunction with resource virtualization. Network virtualization is classified as external (combining many networks or portions of networks into virtual units) or internal (providing network-like functionality to software containers on a single system). Note that the virtualized entities resulting from network virtualization are still implemented to some extent using hardware such as processors 152 or 175 and memories 155 and 171, and such virtualized entities also produce technical effects.

[0079] Computer readable memories 125, 155, and 171 may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Computer readable memories 125, 155, and 171 may be components for performing storage functions. Processors 120, 152, and 175 may be of any type suitable for the local technical environment and may include, as non-limiting examples, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Processors 120, 152, and 175 may be components for performing functions such as controlling UE 110, RAN node 170, and other functions as described herein.

[0080] In general, various embodiments of user device 110 may include, but are not limited to, cellular phones such as smart phones, tablet computers, personal digital assistants (PDAs) with wireless communication capabilities, portable computers with wireless communication capabilities, image capture devices such as digital cameras with wireless communication capabilities, gaming devices with wireless communication capabilities, music storage and playback devices with wireless communication capabilities, Internet devices that allow wireless Internet access and browsing, tablet computers with wireless communication capabilities, and portable units or terminals that include a combination of these functions.

[0081] The embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., application specific integrated circuits), or a combination of software and hardware. In examples of embodiments, the software (e.g., application logic, instruction sets) is maintained on any of a variety of conventional computer-readable media. In the context of this document, a "computer-readable medium" may be a medium capable of containing, storing, communicating, propagating, or transmitting data for use in, for example, a computer (e.g., on a computer). Figure 1An example of a computer is described and depicted in the , or any medium or device or any medium or component associated therewith that can contain or store instructions for use by an instruction execution system, apparatus, or device (such as a computer). Computer-readable media may include computer-readable storage media or other devices, which can be any medium or component that can contain or store instructions for use by or in connection with an instruction execution system, apparatus, or device (such as a computer).

[0082] Having thus introduced a suitable but non-limiting technical context for implementing example embodiments of the invention, the example embodiments will now be described in more detail.

[0083] Figure 2 An example table 200 of radio system parameter set options, such as those defined in NR Release 15, is shown.

[0084] like Figure 2 As shown, available OFDM parameter sets for a radio system may include subcarrier spacing (kHz) 210, symbol duration (μs) 220, nominal normal CP (μs) 230, minimum (min.) scheduling interval (symbol) 240, minimum scheduling interval (time slot) 250, minimum scheduling interval (ms) 260. The first column 270 indicates values ​​for the LTE system and for NR based on 15kHz subcarrier spacing.

[0085] The NR parameter set options shown in Table 200 are based on 15×2 N kHz subcarrier spacing, where N=0 corresponds to the subcarrier spacing of LTE. Subcarrier spacing of [15 30 60]kHz is suitable for wide areas on traditional cellular bands, such as dense cities. Compared with 15kHz SCS, 30 / 60kHz SCS provides lower latency and wider carrier BW. For example, for frequency bands greater than 10GHz, a frequency of 60khz or higher is required to combat phase noise.

[0086] As described in Table 200, below 6 GHz, the RAN4 agreement on subcarrier spacing in Rel-15 is as follows: [15, 30, 60] kHz may be considered if clear benefits are shown. 6…52.6 GHz: [60, 120] kHz, 240 kHz. The RAN4 agreement on minimum / maximum channel bandwidth in Rel-15 is as follows: below 6 GHz: 5 MHz / 100 MHz, 6…52.6 GHz: 50 MHz / 400 MHz.

[0087] Reference now Figure 3 , Table 300 shows the maximum channel bandwidth based on subcarrier spacing and FFT size.

[0088] The FFT size itself is an implementation issue. However, it can be noted that a 4k FFT is required to support the maximum channel BW (400MHz) on a particular frequency band. Therefore, it can be considered as a feasible FFT size for NR UEs.

[0089] Figure 4 Example embodiments are shown, in particular the 3 different operation modes defined for NB-IoT.

[0090] Regarding Narrowband IoT (Nb-IOT), LTE provides support for NB-IOT with the following design options. Only FDD mode with normal CP length. 180kHz UE RF bandwidth for both DL and uplink. DL uses OFDMA with 15kHz subcarrier spacing: 12 subcarriers are available in one NB-IOT carrier. UL uses SC-FDMA, supporting two options: single-tone transmission and multi-tone transmission. Single-tone transmission can be achieved with 3.75khz SCS. Alternatively, single-tone transmission can be 15kHz SCS. Multi-tone (3, 6, 12) tone transmission can be achieved with 15kHz SCS.

[0091] like Figure 4 As shown, Nb-IOT supports three different operation modes: in-band 410, standalone 420, and guard band 430. In-band 410 may include an in-band Nb IOT 435 within other bands 430. Standalone 420 may allow Nb IOT 435 to be an independent band within other bands 430, but with a gap between Nb IOT 435 and other bands 430. Guard band 430 may allow Nb IOT 435 to have a gap after other bands 430.

[0092] Regarding NR-BWP operation, Rel-15 NR provides details of serving cell adaptive BW via BWP. In Rel-15 NR, UE 110 is instructed to operate on a specific part of the gNB's 170BW, i.e., on the BWP. Up to 4 BWPs can be configured for UL and DL respectively. Most RRC parameters in NR are configured on BWPs. Each BWP can, for example, have a separately configured subcarrier spacing (SCS), cyclic prefix, BW with respect to consecutive PRBs, and the position of the BW in the total BW of the cell. The K0, K1, and K2 values ​​define the time offset from the start of DL allocation reception to PDSCH, the time offset from the end of PDSCH to HARQ-ACK transmission time, and the time offset from the start of UL grant reception to PUSCH transmission, respectively. In the case of non-paired spectrum (e.g., TDD), the UL BWP and DL BWP can be paired, in which case the center frequencies of the two BWPs are required to be the same. For example, one of the BWPs can be defined as the default BWP to facilitate UE 110 to save battery.

[0093] In Rel-15 NR, UE 110 can have only one BWP active at a time. The active BWP may be indicated by a field in the DCI or by RRC signaling. BWP switching occurs after UE 110 has received signaling to change the active BWP, but the switching time has not yet been determined. For example, the switching time may be on the order of 0.4 ms to 0.6 ms. The minimum switching time for UE 110 may vary depending on the scenario (e.g., carrier frequency, bandwidth) and UE 110 category. UE 110 may also fall back to the default BWP after a configured period of inactivity.

[0094] Figure 5 An example table 500 is shown with bandwidths for different signals, parameter sets for different radio systems (e.g., NR) supported by NR (15, 30, 60) and two additional example parameter sets (3.75, 7.5) that may be implemented in a radio system according to an example embodiment.

[0095] like Figure 5 As shown, SCS (kHz) 510 of 3.75, 7.5, 15, 30 and 60 may be provided. Each SCS 510 has a corresponding PSS / SSS (MHz) 520 of 12 PRBs, a PBCH (MHz) 530 of 20 PRBs, and a CORESET #0 540 of 24 PRBs. An SCS 510 of 3.75 may have a corresponding PSS / SSS (MHz) 520 of 0.54, a PBCH (MHz) 530 of 0.9, and a CORESET #0 540 of 1.08. An SCS 510 of 7.5 may have a corresponding PSS / SSS (MHz) 520 of 1.08, a PBCH (MHz) 530 of 1.8, and a CORESET #0 540 of 2.16. An SCS 510 of 15 may have a corresponding PSS / SSS (MHz) 520 of 2.16, a PBCH (MHz) 530 of 3.6, and a CORESET #0 540 of 4.32. An SCS 510 of 30 The SCS 510 of 510 may have a corresponding PSS / SSS (MHz) 520 of 4.32, a PBCH (MHz) 530 of 7.2, and a CORESET #0 540 of 8.64. The SCS 510 of 60 may have a corresponding PSS / SSS (MHz) 520 of 8.64, a PBCH (MHz) 530 of 14.4, and a CORESET #0 540 of 17.28.

[0096] The BWP bandwidth is (e.g., proportionally) connected to the UE 110 power consumption: the smaller the RF bandwidth, the smaller the UE 110 power consumption. NR Rel-15 based on the current numerology (e.g., 15kHz subcarrier spacing) suffers from significant power consumption (compared to LTE-M and NB-IOT). This is because the minimum BWP size per UE 110 (in DL) is limited to 24 PRBs (SSB / CORESET#0). The minimum BWP sizes for different SCSs related to operation at frequencies below 6GHz are shown in Table 500.

[0097] Note that operation with 15kHz SCS (the smallest SCS currently supported) requires a DL BWP size of at least 4.32MHz. In the example embodiment with SCS 3.75kHz, this number is reduced to 1.08MHz.

[0098] To reduce power consumption of UE 110, example embodiments may operate with a BWP less than 24 PRBs. On the other hand, redesigning existing systems (including a BWP of 24 PRBs) should be avoided as much as possible. For example, the DL control channel structure is a complex subsystem (for both UE 110 and gNB 170). Therefore, example embodiments operate, for example, with a BWP of 24 PRBs. Also from an overhead perspective, example embodiments may provide low power operation using existing signals defined for "normal" NR operation.

[0099] Latency is one of the key requirements defined for radio systems such as 5G. In IoT scenarios, low latency is required, especially for UL initiated transmissions. Example embodiments provide systems and methods for achieving low latency and low power consumption simultaneously.

[0100] Figure 6 Shown is an example embodiment of a DL-BWP scenario 600. The scenario 600 includes a TRS (Tracking Reference Signal) 610 with a given periodicity, a DL-BWP (eg, 24 PRBs) 620, and a DL sub-BWP (eg, 6 PRBs) 630 for IoT.

[0101] Example embodiments provide measurement relaxation in IOT. Example embodiments provide an operation mode for IOT operation that provides low latency in UL with very little power consumption. The operation mode of example embodiments may be based on a specific BWP configuration defined for an IOT terminal.

[0102] In an example configuration, an IOT terminal configured with a specific active bandwidth portion (eg, 24 PRBs) operates in narrowband mode within the configured DLBWP (→DL sub-BWP). Figure 5 An example framework of a configuration is shown.

[0103] UE 110 may be configured with an active (DL) BWP of 24 PRBs. A signal that facilitates time and frequency tracking of UE 110 is the TRS. A synchronization signal block SSB consisting of PSS / SSS / PBCH may be used as a supplement or in addition (SSB covers 20 PRBs). TRS is transmitted with a specific period ([10, 20, 40, 80] ms). TRS covers the entire BWP (= 24 PRBs in the current example). The TRS BW in NR Rel-15 is: min(BWP, 52 PRBs).

[0104] The RF bandwidth of IoT terminals covers part of the active DL BWP: Figure 5 In the example shown, it is equal to 6 PRBs. The UL RF BW of UE 110 may be the same as that in DL or different from that in DL.

[0105] IOT terminals operating within the DL sub-BWP benefit from measurement relaxation (compared to normal BWP operation). Example primary measurement relaxation scheme: reduced measurement bandwidth → reduced processing of DL synchronization signals in frequency. Example auxiliary measurement relaxation scheme: reduced measurement period → reduced processing of DL synchronization signals in time. In an example embodiment, cell-specific signals are used for measurement (e.g., PSS / SSS / PBCH DMRS). For beamforming-based operation, UE 110 can monitor multiple SSBs. This can also be reduced to monitoring only the preferred SSB unless the measurement degradation exceeds certain criteria.

[0106] Although synchronization accuracy is reduced (due to measurement relaxation), the IOT terminal is able to send predefined UL (control) signals when it operates according to relaxed time / frequency synchronization and sub-BWP. The relevant details of UL BWP configuration and operation will be discussed in more detail below.

[0107] When operating according to the sub-BWP configuration in the UL, the IOT terminal may not be able to adjust the UL timing advance (when the UL returns to operation based on the normally active BWP, the UL TA may be updated again).

[0108] Figure 7 An example BWP adaptation 700 is shown. Figure 7 Example operations of a UE (=IOT terminal) when configured for sub-BWP operation (with corresponding steps 0 to 6) are shown. Operations 700 include periodic TRS 710 for DL ​​730.

[0109] In step 0( Figure 7In an example embodiment, gNB 170 configures the size and location of the DL sub-BWP within the DL BWP. When operating according to the sub-BWP configuration, UE 110 may or may not be able to receive DL control channels. In the latter case, UE 110 may periodically switch back to BWP operation to monitor the DL control channels, for example, according to predefined paging occasions.

[0110] At step 1, UL data arrives at the buffer of UE 110 (eg, from a higher layer). UE 110 prepares to send a predefined UL signal using a sub-BWP configuration (UL sub-BWP) defined for UL operation. Figure 7 The example shown shows a case where the operation based on the sub-bandwidth portion covers both the uplink operation and the downlink operation. This is not always the case. In another embodiment, the DL (or UL) can switch between the sub-BWP configuration and the BWP configuration, while the UL (or DL) always operates according to the BWP configuration.

[0111] In step 2, UE 110 transmits a predefined UL signal (signal #2). The resources and signal format used are preconfigured by gNB 170 (transmissions may involve multiple repetitions to maximize coverage / reliability). In an example embodiment, the UL signal to be transmitted is a dedicated scheduling request or a dedicated PRACH preamble. In another example embodiment, the SR or PRACH preamble may be configured to be common to a group (IOT) of UEs 110. In yet another example embodiment, the transmission may contain not only the preamble, but also PUSCH data.

[0112] In step 3, UE 110 performs a switch from sub-BWP based operation to BWP based operation (for both DL and UL). This includes the possibility of RF re-tuning at UE 110. Thus, UE 110 may change the center frequency of the oscillator and may adapt analog filters (for both DL and UL) and analog-to-digital conversion circuits or digital-to-analog conversion circuits according to BWP based operation. The maximum duration of step 3 may be predefined by the specification. For example, it may be of the order of 0.5 ms or higher.

[0113] In step 4, UE 110 may assume that aperiodic (wideband) TRS is available after step 3 (e.g., based on gNB 170 triggering), enabling UE 110 to perform frequency / timing synchronization after RF retuning (right). UE 110 may also perform frequency / timing synchronization from other DL signals (e.g., PDCCH DMRS).

[0114] In step 5, UE 110 starts monitoring PDCCH according to the predefined configuration (defined for normal BWP operation). UE 110 determines that an UL resource allocation grant has been received based on PDCCH monitoring. This step may also involve receiving an SRS / PRACH request from gNB 170 (as it will enable TA update later). Another option is to use preconfigured SRS / PRACH resources.

[0115] At step 6, UE 110 transmits PUSCH (and possibly SRS) according to the received UL resource allocation grant.

[0116] In step 7 (step not shown), UE 110 may receive TA updates, receive DL data, and receive UL data based on the gNB 170 scheduling decision.

[0117] For example, when the UE 110 buffer is empty again, the UE 110 may fall back to the sub-BWP mode (and corresponding RF configuration) at some point. The exact fallback time may be based on, for example, explicit indications from the gNB 170 and / or an inactivity timer.

[0118] When UE 110 operates according to the sub-BWP configuration, it can be regarded as DRX from a high-level perspective (for example, when UE 110 is occasionally configured for operation based on normal BWP, gNB 170 or other network devices may schedule DL / UL data only at certain predefined moments).

[0119] In one embodiment, a DL sub-BWP signal (e.g., a cell common sequence) is used to wake up UE 110 for DL ​​data reception (rather than defining a period for the UE to operate in BWP mode). According to an example embodiment, UE 110 may be placed in sub-BWP mode until awakened by gNB 170 or until it has UL data to send.

[0120] Figure 8 An example embodiment 800 of different UL BWP configurations in frequency / time is shown.

[0121] With respect to UE BWP operation, gNB 170 may need to have special arrangements for UL sub-BWP 840 operation that occurs when UE 110 has reduced synchronization accuracy in frequency and / or time. In an example embodiment, such operation is restricted to specific time 810 / frequency resources 820 (→ see Figure 8 Due to deteriorated synchronization, it may be necessary to use guard bands / times between resources depending on the active BWP configuration.

[0122] The UL sub-BWP 840 may not need to be located within the (active) UL BWP 830. The UL sub-BWP 840 may operate according to a specific parameter set (e.g., subcarrier spacing < SCS defined for the UL BWP 830). For example, the UL sub-BWP 840 may operate according to SCS 3.75 khz or 7.5 khz with longer cyclic prefixes (→ these SCS may be more robust to UL time synchronization errors). The UL sub-BWP 840 may be configured to operate according to the signal to be transmitted (e.g., Figure 7 The size is determined based on signal #2 in (step 2)). Depending on the bandwidth of the sub-BWP, the UL sub-BWP 840 can be regarded as a UL BWP for the UE.

[0123] For UL sub-BWP 840 operation, UE 110 may be configured via higher layers with Figure 7 All required Tx parameters corresponding to signal #2 in . These signals may have predefined periodicity, slot / symbol offset, and duration. The transmission may be based on a predefined / preconfigured format, such as a PUCCH format or a PRACH format defined for SR. The transmission may be done using preconfigured resources (e.g., resource index, cyclic shift, PRB, orthogonal cover code, DMRS resources). The resources may also contain a data portion (e.g., with a predefined MCS). In this case, the transmission may be viewed as a contention-based two-step RACH.

[0124] Fig. 9 A flow chart 900 is shown representing the operation of UE 110 according to an example embodiment.

[0125] Initially, at step 1, the UE 110 operates according to the sub-BWP configuration in UL and DL (block 910). For DL ​​operation, the sub-BWP may contain only the bandwidth configuration (position, size) and predefined rules for DL ​​synchronization signal (e.g., TRS, SSB) processing. In one embodiment, the UL sub-BWP is a subset of the active UL BWP configuration. In another embodiment, the UL sub-BWP configuration is a specific (separate) UL BWP configuration (which may or may not overlap with the active UL BWP in frequency). In yet another embodiment, the UL sub-BWP configuration is the same as the active UL BWP configuration.

[0126] In step 2 (block 920), consistent with example embodiments described herein, the (delay-critical) data in the UE buffer may determine a requirement (e.g., a need) for RF retuning. This need may be initiated by a UL trigger ( Figure 7In an alternative example embodiment, RF retuning may be initiated by a time-based trigger, which allows UE 110 to perform PDCCH monitoring for other time periods based on the active BWP configuration, such as for paging or other purposes.

[0127] UE 110 may perform a switch from sub-BWP based operation to BWP based operation for at least one of DL and UL. This includes the possibility of RF retuning at UE 110 (step 3, block 930). Retuning may be required in order to operate again according to BWP based operation. Retuning involves at least one of the following changes: a change in center frequency, or a change in RF bandwidth. Thus, UE 110 may be able to change the center frequency of the oscillator, and may be able to adapt analog filters (for DL ​​and / or UL) according to BWP based operation. UE 110 may assume that after step 3 (based on gNB triggering) a non-periodic (wideband) TRS or other predefined DL RS is available, so that UE 110 can perform frequency / timing synchronization after RF retuning (e.g., immediately). Wideband PDCCH DMRS is an example of other predefined DL RS.

[0128] UE 110 may perform operations within the BWP (step 4, block 940). For example, UE 110 may begin monitoring the PDCCH according to a predefined configuration. UE 110 determines based on the PDCCH monitoring that an UL resource allocation grant has been received. This step may also involve an SRS / PRACH request from UE 110 (which would enable TA updates). UE 110 transmits a PUSCH (and possibly an SRS) based on the received UL resource allocation grant. UE 110 may also receive TA updates, receive DL data, and receive UL data based on the gNB 170 scheduling decision.

[0129] UE 110 may determine the need for power conservation at 950, returning to step 1 (block 910).

[0130] In step 5 ( Fig. 9 170 and / or an inactivity timer).

[0131] Without in any way limiting the scope, interpretation or application of the claims appearing below, the technical effect of one or more example embodiments disclosed herein is to simultaneously (in parallel) support low power consumption with reasonable delay performance (e.g., delays that are acceptable to most current applications). This feature is beneficial not only to IOT terminals, but also to normal UEs. The example embodiments require limited (e.g., quite small) additional specifications to support power optimization mode (e.g., the example embodiments can reuse existing control channels defined for NR-Rel-15).

[0132] Another technical effect of example embodiments is reduced UE cost, particularly when combined with 3.75 khz subcarrier spacing (e.g., for both UL and DL). Another technical effect is that example embodiments do not require additional overhead due to power optimization operation: relaxed measurement configuration can be made based on current signals. Another technical effect of example embodiments is that the added system complexity is (e.g., relatively) small because control channels are not touched. The impact on gNB scheduler operation is also small.

[0133] Example embodiments may provide a method comprising: performing, by a terminal device, sub-bandwidth portion-based operation; determining a requirement for radio frequency retuning; switching from sub-bandwidth portion-based operation to bandwidth portion-based operation; and performing bandwidth portion-based operation.

[0134] According to the example embodiment described in the above paragraphs, the operation based on the sub-bandwidth portion is in at least one of an uplink operation and a downlink operation.

[0135] According to the example embodiment described in the above paragraphs, wherein for the downlink operation, at least one sub-bandwidth portion only contains bandwidth configuration and predefined rules for downlink synchronization signal processing.

[0136] According to the example embodiment described in the above paragraph, at least one uplink sub-bandwidth portion is a subset of the active uplink bandwidth portion configuration.

[0137] According to the example embodiment described in the above paragraphs, at least one uplink sub-bandwidth portion is a specific uplink bandwidth portion configuration.

[0138] According to the example embodiment described in the above paragraphs, the uplink sub-bandwidth portion configuration is the same as the active uplink bandwidth portion configuration.

[0139] According to the example embodiment described in the above paragraph, determining the requirement for radio frequency retuning further comprises: initiating radio frequency retuning for at least one of uplink operation and downlink operation based on uplink data in a buffer associated with the terminal device.

[0140] According to the example embodiment described in the above paragraph, determining the requirement for radio frequency retuning also includes: determining the requirement based on a time-based trigger, wherein the time-based trigger instructs the terminal device to perform physical downlink control channel monitoring.

[0141] According to the example embodiment described in the above paragraphs, performing a switch from sub-bandwidth portion based operation to bandwidth portion based operation further comprises: performing radio frequency retuning; and performing frequency and time synchronization.

[0142] According to the example embodiments described in the above paragraphs, it is assumed that a non-periodic tracking reference signal is available; and frequency / timing synchronization is performed after the radio frequency retuning.

[0143] According to the example embodiment described in the above paragraphs, determining a requirement for radio frequency retuning further comprises: sending an uplink trigger, wherein the uplink trigger is one of: a trigger only, and a trigger plus a limited amount of data.

[0144] An example embodiment is provided as an apparatus comprising at least one processor and at least one non-volatile memory comprising computer program code, the at least one memory and the computer program code being configurable to, with the at least one processor, cause the apparatus to: perform sub-bandwidth portion-based operation; determine a requirement for radio frequency retuning; switch from sub-bandwidth portion-based operation to bandwidth portion-based operation; and perform bandwidth portion-based operation.

[0145] According to the example embodiments described in the above paragraphs, the operation based on the sub-bandwidth portion is in at least one of an uplink operation and a downlink operation.

[0146] According to the example embodiment described in the above paragraphs, wherein for the downlink operation, at least one sub-bandwidth portion only contains bandwidth configuration and predefined rules for downlink synchronization signal processing.

[0147] According to the example embodiment described in the above paragraph, at least one uplink sub-bandwidth portion is a subset of the active uplink bandwidth portion configuration.

[0148] According to the example embodiment described in the above paragraphs, at least one uplink sub-bandwidth portion is a specific uplink bandwidth portion configuration.

[0149] According to the example embodiment described in the above paragraphs, the uplink sub-bandwidth portion configuration is the same as the active uplink bandwidth portion configuration.

[0150] According to the example embodiment described in the above paragraph, when the requirement for RF retuning is determined, at least one processor further initiates RF retuning for at least one of uplink operation and downlink operation based on uplink data in a buffer associated with the terminal device.

[0151] According to the example embodiments described in the above paragraphs, the requirement is determined based on a time-based trigger, wherein the time-based trigger instructs the terminal device to perform physical downlink control channel monitoring.

[0152] An example embodiment is provided as an apparatus comprising: means for performing sub-bandwidth portion based operation; means for determining a requirement for radio frequency retuning; means for switching from sub-bandwidth portion based operation to bandwidth portion based operation; and means for performing bandwidth portion based operation.

[0153] According to the example embodiment described in the above paragraphs, the operation within the sub-bandwidth portion is at least one of an uplink operation and a downlink operation.

[0154] According to the example embodiment described in the above paragraphs, wherein for the downlink operation, at least one sub-bandwidth portion only contains bandwidth configuration and predefined rules for downlink synchronization signal processing.

[0155] According to the example embodiment described in the above paragraph, at least one uplink sub-bandwidth portion is a subset of the active uplink bandwidth portion configuration.

[0156] According to the example embodiment described in the above paragraphs, at least one uplink sub-bandwidth portion is a specific uplink bandwidth portion configuration.

[0157] According to the example embodiment described in the above paragraphs, the uplink sub-bandwidth portion configuration is the same as the active uplink bandwidth portion configuration.

[0158] According to the example embodiment described in the above paragraph, the component for determining the requirement for radio frequency retuning also includes: a component for determining the requirement based on a time-based trigger, wherein the time-based trigger instructs the terminal device to perform physical downlink control channel monitoring.

[0159] According to the example embodiment described in the above paragraph, it also includes: a component for sending an uplink trigger, wherein the uplink trigger is one of the following: only a trigger, and a trigger plus a limited amount of data.

[0160] The embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., application specific integrated circuits), or a combination of software and hardware. In example embodiments, the software (e.g., application logic, instruction set) is maintained on any of a variety of conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any medium capable of containing, storing, communicating, propagating, or transmitting instructions for use by, for example, a computer (e.g., Figure 1 Any medium or component for use by or in connection with an instruction execution system, apparatus, or device (e.g., an example of a computer) is described and depicted. Computer-readable media may include computer-readable storage media (e.g., memory 125, 155, 171 or other devices), which may be any medium or component that can contain, store, and / or transmit instructions for use by or in connection with an instruction execution system, apparatus, or device (e.g., a computer). Computer-readable storage media do not include propagated signals.

[0161] If desired, the different functions discussed herein may be performed in different orders and / or in parallel with each other. In addition, if desired, one or more of the above functions may be optional or may be combined.

[0162] While various aspects are set forth above, other aspects include other combinations of features from the described embodiments, not just the combinations described above.

[0163] It should also be noted here that although the above describes example embodiments, these descriptions should not be viewed in a limiting sense. Rather, several changes and modifications may be made without departing from the scope of the present invention.

[0164] Although various aspects of the invention are set out in the independent claims, further aspects of the invention comprise other combinations of features from the described embodiments and / or the dependent claims with features of the independent claims, and not just the combinations explicitly set out in the claims.

[0165] It is also noted herein that while the above describes example embodiments, these descriptions are not to be viewed in a limiting sense. Rather, several variations and modifications are possible without departing from the scope of the present invention as defined in the appended claims.

[0166] In general, various embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, 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, but the invention is not limited thereto. Although various aspects of the invention may be illustrated and described using block diagrams, flow charts, or using some other illustrations, it is well known that the blocks, devices, systems, techniques, or methods described herein may be implemented as hardware, software, firmware, dedicated circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof, as non-limiting examples.

[0167] Embodiments may be implemented in various components such as integrated circuit modules. The design of integrated circuits is generally a highly automated process. Complex and powerful software tools are available to convert a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0168] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All embodiments described in this specification are exemplary embodiments provided to enable persons skilled in the art to make or use the invention, without limiting the scope of the invention which is defined by the claims.

[0169] The foregoing description has provided by way of exemplary and non-limiting examples a complete and informative description of the best method and apparatus presently contemplated by the inventors for carrying out the invention. However, various modifications and variations may become apparent to those skilled in the relevant arts in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. Nevertheless, all such and similar modifications of the teachings of the present invention will still fall within the scope of the present invention.

[0170] It should be noted that the terms "connected," "coupled," or any variations thereof, mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between elements may be physical, logical, or a combination thereof. As used herein, as a few non-limiting and non-exhaustive examples, two elements may be considered to be "connected" or "coupled" together by using one or more wires, cables, and / or printed electrical connections, and by using electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, microwave region, and optical (visible and invisible) region.

[0171] Furthermore, some features of the preferred embodiments of the present invention may be used to advantage without the corresponding use of other features.Therefore, the above description should be considered as merely illustrative of the principles of the present invention, rather than limiting the present invention.

Claims

1. A method for communication, comprising: The terminal device performs operations based on the sub-bandwidth portion; Determine requirements for RF retuning; initiating the radio frequency retuning; determining, based on a triggering by a radio access network node, that an aperiodic tracking reference signal is available; performing at least one of frequency synchronization and timing synchronization after the radio frequency retuning based on the determining that the aperiodic tracking reference signal is available; Switching from said sub-bandwidth portion based operation to bandwidth portion based operation; as well as performing the bandwidth-part-based operation; wherein the operation based on the sub-bandwidth portion is in at least one of an uplink operation and a downlink operation; wherein, for said downlink operation, at least one sub-bandwidth portion contains only bandwidth configuration and predefined rules for downlink synchronization signal processing; The switching from the sub-bandwidth portion based operation to the bandwidth portion based operation further comprises: performing radio frequency retuning.

2. The method of claim 1, wherein at least one uplink sub-bandwidth portion is a subset of an active uplink bandwidth portion configuration.

3. The method of claim 1, wherein at least one uplink sub-bandwidth portion is a specific uplink bandwidth portion configuration.

4. The method of claim 1, wherein the uplink sub-bandwidth portion configuration is the same as the active uplink bandwidth portion configuration.

5. The method according to any one of claims 1 to 4, wherein determining a requirement for radio frequency retuning further comprises: The radio frequency retuning is initiated for at least one of an uplink operation and a downlink operation based on uplink data in a buffer associated with the terminal device.

6. The method of any one of claims 1 to 4, wherein determining the requirement for the radio frequency retuning further comprises: The requirement is determined based on a time-based trigger, wherein the time-based trigger instructs the terminal device to perform physical downlink control channel monitoring.

7. The method according to any one of claims 1 to 4, wherein performing a switch from the sub-bandwidth portion based operation to the bandwidth portion based operation further comprises: Perform frequency and time synchronization.

8. The method of any one of claims 1 to 4, wherein determining the requirement for the radio frequency retuning further comprises sending an uplink trigger, wherein the uplink trigger is one of: a trigger only, and a trigger plus a limited amount of data.

9. An apparatus for communication, comprising: means for performing operations based on sub-bandwidth portions; Components for determining requirements for radio frequency retuning; means for initiating said radio frequency retuning; means for determining, based on a triggering by a radio access network node, that an aperiodic tracking reference signal is available; means for performing at least one of frequency synchronization and timing synchronization after said radio frequency retuning based on said determining that said aperiodic tracking reference signal is available; means for switching from sub-bandwidth portion based operation to bandwidth portion based operation; and means for performing said bandwidth portion-based operation; wherein the operation within the sub-bandwidth portion is at least one of an uplink operation and a downlink operation; wherein for said downlink operation, at least one sub-bandwidth portion contains only bandwidth configuration and predefined rules for downlink synchronization signal processing; Wherein said means for performing a switch from said sub-bandwidth portion based operation to said bandwidth portion based operation comprises: means for performing a radio frequency retuning.

10. The apparatus of claim 9, wherein at least one uplink sub-bandwidth portion is a subset of an active uplink bandwidth portion configuration.

11. The apparatus of claim 9, wherein at least one uplink sub-bandwidth portion is a specific uplink bandwidth portion configuration.

12. The apparatus of claim 9, wherein the uplink sub-bandwidth portion configuration is the same as the active uplink bandwidth portion configuration.

13. The apparatus of any one of claims 9 to 12, wherein the means for determining a requirement for radio frequency retuning further comprises: Means for determining the requirement based on a time-based trigger, wherein the time-based trigger instructs a terminal device to perform physical downlink control channel monitoring.

14. The apparatus of any one of claims 9 to 12, wherein the means for determining a requirement for radio frequency retuning further comprises: Means for sending an uplink trigger, wherein the uplink trigger is one of: a trigger only, and a trigger plus a limited amount of data.

15. A non-transitory program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine for performing operations comprising: performing, by a terminal device, an operation within at least one sub-bandwidth portion; Determine requirements for RF retuning; initiating the radio frequency retuning; determining, based on a triggering by a radio access network node, that an aperiodic tracking reference signal is available; performing at least one of frequency synchronization and timing synchronization after the radio frequency retuning based on the determining that the aperiodic tracking reference signal is available; Switching from sub-bandwidth portion-based operation to bandwidth portion-based operation; as well as performing the bandwidth-part-based operation; wherein the operation based on the sub-bandwidth portion is in at least one of an uplink operation and a downlink operation; wherein, for said downlink operation, at least one sub-bandwidth portion contains only bandwidth configuration and predefined rules for downlink synchronization signal processing; The switching from the sub-bandwidth portion based operation to the bandwidth portion based operation further comprises: performing radio frequency retuning.

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