Patent Application
20210091912
The present disclosure relates to wireless communications and, more particularly, to bandwidth part (BWP) mechanisms for vehicle-to-everything (V2X) communication.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
New radio (NR) cellular technology is designed to support various and new industrial use cases, such as enhanced mobile broadband (eMBB), ultra-reliable and low latency communication (URLCC), massive machine type communication (mMTC), and vehicle-to-everything (V2X) communication. These use cases require highly challenging quality of service (QoS) metrics, such as peak data rate, latency, reliability, availability, and coverage bandwidth. Inefficient energy consumption leads to poor user experience. NR radio access technology improves battery efficiency and achieves power savings through, for example, bandwidth part (BWP) switching. A user equipment (UE) can open a wider BWP when a large amount of data is scheduled, and switch the wider BWP to a narrower BWP for monitoring control channels to reduce power consumption.
Aspects of the disclosure provide a method for switching to the next Uu bandwidth part (BWP) from a sidelink BWP (SL BWP) switched from an original Uu BWP. The method can include operating, at a user equipment (UE), on an original Uu BWP, switching from the original Uu BWP to an SL BWP, and switching from the SL BWP to the next Uu BWP. In some embodiments, switching from the SL BWP to the next Uu BWP can include switching from the SL BWP to the original Uu BWP followed by switching from the original Uu BWP to the next Uu BWP. For example, switching from the original Uu BWP to the next Uu BWP can include switching from the original Uu BWP to a default Uu BWP followed by switching from the default Uu BWP to the next Uu BWP. In other embodiments, switching from the SL BWP to the next Uu BWP can include switching from the SL BWP to a default Uu BWP followed by switching from the default Uu BWP to the next Uu BWP. In various embodiments, switching from the SL BWP to the next Uu BWP can include switching from the SL BWP to a default SL BWP followed by switching from the default SL BWP to the next Uu BWP.
For example, the method can further include receiving a signaling indicating a switch from the SL BWP to the next Uu BWP. For example, the signaling can be a radio resource control (RRC) signaling, a media access control (MAC) control element (CE), or downlink control information (DCI).
In some embodiments, the method can further include setting a sidelink timer (SL timer), and the SL BWP can be switched back to the next Uu BWP after the SL timer expires. In other embodiments, the method can further include setting a Uu timer, and switching from the SL BWP to the next Uu BWP can include switching from the SL BWP to the original Uu BWP after the SL timer expires followed by switching from the original Uu BWP to the next Uu BWP or a default Uu BWP after the Uu timer expires. For example, the Uu timer has a length longer than a length of the SL timer. In some embodiments, the method can further include setting a Uu timer, and switching from the original Uu BWP to the next Uu BWP can include switching from the original Uu BWP to a default Uu BWP after the SL timer expires and switching from the default Uu BWP to the next Uu BWP after the Uu timer expires.
Aspects of the disclosure also provide an apparatus for switching to the next Uu BWP from an SL BWP that is switched from an original Uu BWP. For example, the apparatus can include receiving circuitry and processing circuitry. The receiving circuitry can be configured for receiving wireless signals. The processing circuitry can be configured for operating on an original Uu BWP, switching from the original Uu BWP to the SL BWP, and switching from the SL BWP to the next Uu BWP in response to the wireless signals. In an embodiment, the wireless signals can instruct the processing circuitry to switch from the SL BWP to the original Uu BWP and then switch from the original Uu BWP to the next Uu BWP when the processing circuitry switches from the SL BWP to the next Uu BWP. For example, the wireless signals can further instruct the processing circuitry to switch from the original Uu BWP to a default Uu BWP and then switch from the default Uu BWP to the next Uu BWP when the processing circuitry switches from the original Uu BWP to the next Uu BWP. In other embodiments, the wireless signals can instruct the processing circuitry to switch from the SL BWP to a default Uu BWP and then switch from the default Uu BWP to the next Uu BWP when the processing circuitry switches from the SL BWP to the next Uu BWP. In various embodiments, the wireless signals can instruct the processing circuitry to switch from the SL BWP to a default SL BWP and then switch from the default SL BWP to the next Uu BWP when the processing circuitry switches from the SL BWP to the next Uu BWP.
In some embodiments, the apparatus can further include an SL timer configured to be set to a length, and the processing circuitry can be further configured for switching from the SL BWP to the next Uu BWP after the SL timer expires. In other embodiments, the apparatus can further include a Uu timer configured to be set to a length, and the processing circuitry can be further configured for switching from the SL BWP to the original Uu BWP after the SL timer expires and then switching from the original Uu BWP to the next Uu BWP or a default Uu BWP after the Uu timer expires. In some embodiments, the apparatus can further include a Uu timer configured to be set to a length, and the processing circuitry can be further configured for switching from the original Uu BWP to a default Uu BWP after the SL timer expires, and switching from the default Uu BWP to the next Uu BWP after the Uu timer expires. For example, the Uu timer can have a length longer than a length of the SL timer.
Various embodiments of this disclosure that are proposed as examples will be described in detail with reference to the following figures, wherein like numerals reference like elements, and wherein:
A user equipment (UE) can operate on a wide Uu bandwidth part (BWP) when a base station (BS) needs to transmit a great amount of data, or be switched to operate on a narrow Uu BWP to save power. The UE can also be switched between a Uu BWP and a sidelink BWP (SL BWP). An SL BWP cannot be an initial BWP, and has to be switched from a Uu BWP, e.g., an original Uu BWP. According to some embodiments of the disclosure, the SL BWP that is switched from the original Uu BWP can be switched to the next Uu BWP directly. According to other embodiments of the disclosure, the SL BWP that is switched from the original Uu BWP can be switched to a default Uu BWP and may then additionally switched from the default Uu BWP to the next Uu BWP. According to various embodiments of the disclosure, the SL BWP that is switched from the original Uu BWP can be switched back to the original Uu BWP first and then switched from the original Uu BWP to the next Uu BWP. Alternatively, the SL BWP that is switched from the original Uu BWP can be switched back to the original Uu BWP first and then switched from the original Uu BWP to a default Uu BWP, and may then additionally switched from the default Uu BWP to the next Uu BWP. According to some other embodiments of the disclosure, the SL BWP that is switched from the original Uu BWP can be switched to a default SL BWP and may then additionally switched from the default SL BWP to the next Uu BWP.
LTE is designed under the assumption that all devices (e.g., the UE 120) are capable of the maximum carrier bandwidth of 20 MHz. The same assumption is not reasonable for NR, given the very wide carrier bandwidth supported. Consequently, means for handling different device capabilities in terms of bandwidth support must be included in the NR design. Furthermore, receiving a very wide bandwidth can be expensive in terms of power consumption compared to receiving a narrower bandwidth. It is better that in NR a device can employ a narrower bandwidth to monitor control channel and to receive data transmission of small to medium size, and adapt to a wider bandwidth when a large amount of data is scheduled. NR defines bandwidth parts (BWPs) to handle the above two aspects.
A BWP is a contiguous set of physical resource blocks (PRBs), selected from a contiguous subset of the common resource blocks for a given numerology on a given carrier. The UE 120 can be configured with up to four downlink BWPs (DL BWPs) in the downlink with a single DL BWP being active (i.e., the active DL BWP) at a given time. Also, the UE 120 can be configured with up to four uplink BWPs (UL BWPs) in the uplink with a single UL BWP being active (i.e., the active UL BWP) at a given time. The DL BWPs and the UL BWPs are collectively referred to as Uu BWPs. If the UE 120 is configured with a supplementary uplink, the UE 120 can in addition be configured with up to four supplementary UL BWPs in the supplementary uplink with a single supplementary UL BWP being active at a given time. The four DL/UL BWPs consist of initial, active and UE-specific DL/UL BWPs. The UE 120 is not expected to receive physical downlink shared channel (PDSCH), physical downlink control channel (PDCCH) or channel state information-reference signal (CSI-RS) (except for radio resource management (RRM)) outside the active DL BWP. Similarly, the UE 120 shall not transmit physical uplink shared channel (PUSCH) or physical uplink control channel (PUCCH) outside the active UL BWP.
Each BWP is defined by at least the following configuration parameters: numerology, including cyclic prefix (CP) length, SCS and symbol duration; frequency location, including an offset between the BWP and a reference point; bandwidth size in terms of physical resource blocks (PRBs); and control resource set (CORESET).
According to the 3rd generation partnership project (3GPP) TS 38.321, BWP selection and switching can be done with the following mechanisms. Radio resource control (RRC)-based adaptation (e.g., using a dedicated RRC signaling) is suitable for semi-static cases since the processing of RRC messages requires extra time, letting the latency reach as long as 10 msec. Media access control (MAC) control element (CE) adaptation is used upon initiation of a random access procedure. Downlink control information (DCI)-based adaptation (e.g., using a PDCCH DCI) is based on PDCCH channel where a specific BWP can be activated by BWP indicator in DCI format 0_1 (UL grant) and DCI format 1_1 (DL scheduling). DCI-based adaptation, though having latency as low as 2 msec, requires additional considerations for error case handling, as the UE 120 may fail to decode the DCI having the BWP activation/deactivation command. To help to recover from such a DCI lost scenario, timer-based implicit fallback to default BWP (e.g., a bwp-inactivityTimer) is designed to mitigate possible DCI errors. After the UE 120 receives the DCI-based BWP switching command, the timer starts to run. If the UE 120 is not explicitly scheduled with a BWP after the timer expires, it will automatically switch its active DL BWP to a default BWP.
There is an initial BWP for the UE 120 during the initial access until the UE 120 is explicitly configured with BWPs during or after RRC connection establishment. For a serving cell of the BS 110, the UE 120 can be provided by defaultDownlink BWP_Id a default DL BWP among the configured DL BWPs. If the UE 120 is not provided a default DL BWP by defaultDownlink BWP_Id, the default DL BWP is the initial DL BWP.
A BWP switching delay 650 can at least span from the beginning of the first operation 610 (i.e., upon the reception of the DCI switching command) till the end of the fourth operation 640, at which the applying new parameter is complete. From RANI perspective, the BWP switching delay 650 can be the time duration from the end of last OFDM symbol of the PDCCH carrying the active BWP switching DCI (i.e., the DCI switching command) till the beginning of a slot indicated by KO in the active DL BWP switching DCI or K2 in the active UL BWP switching DCI. The UE 120 cannot monitor data transmission from the BS 110 until the BWP switching delay 650 passes. In some embodiments, applying new parameters may cause interruption of one or more slots to other active serving cells in the same frequency range where the UE 120 is performing the BWP switching process 600. In this regard, an interruption time 660 can be as long as the time used for RF/BB parameter calculating and loading. In some embodiments, the interruption time 660 can be allowed to start only within the BWP switching delay 650.
From RAN4 perspective, RF tuning time can be different for intra-band scenario and inter-band scenarios. For example, for the intra-band scenario, RF tuning time can be up to 20 μsec if the center frequency is the same before and after the BWP switching (e.g., the BWP allocation scenario 300 of
On the serving cell of the BS 110 of the wireless communication system 100, the UE 120 can be further configured an active sidelink BWP (SL BWP) at a given time. The same SL BWP is used for both Tx and Rx. Configuration signaling for SL BWP is separated from Uu BWP configuration signaling. In a licensed carrier, SL BWP is defined separately from Uu BWP (e.g., UL BWP) from the specification perspective. In some embodiments, the UE 120 is not expected to use different numerology in the configured SL BWP and active UL BWP in the same carrier at a given time. If the active UL BWP numerology is different from the SL BWP numerology, the SL BWP is deactivated. From legacy LTE agreement, the SL-Uu switching does not need to happen immediately after the UE 120 receives a DCI command. The SL-Uu switching can be performed at least four slots after the reception of the DCI command. Therefore, the DCI parsing time should not be considered in V2X BWP switching.
In some embodiments, the original Uu BWP #1 710, the SL BWP 750, the next Uu BWP #2 720 and the default Uu BWP 810 can have the same center frequency. For example, the original Uu BWP #1 710 and the SL BWP 750 can have the same center frequency. In other embodiments, the original Uu BWP #1 710, the SL BWP 750, the next Uu BWP #2 720 and the default Uu BWP 810 can have the same SCS. For example, the original Uu BWP #1 710 and the SL BWP 750 can have the same SCS.
At step 1210, the UE 120 can operate on an original Uu BWP. For example, the UE 120 can operate on the Uu BWP #1 710 initially. In some embodiments, the UE 120 can be in-coverage of a serving cell associated with the BS 110 on a vehicle-to-everything (V2X) carrier.
At step 1220, the UE 120 can be switched to operate from the original Uu BWP to an SL BWP. For example, the UE 120 can be switched from the original Uu BWP #1 710 to operate on the SL BWP 750.
At step 1230, the UE 120 can be switched from the SL BWP to the next Uu BWP directly. For example, the UE 120 can be switched from the SL BWP 750 to the next Uu BWP #2 720 directly, as shown in
At steps 1240 and 1250, the UE 120 can be switched from the SL BWP to the next Uu BWP indirectly. For example, the UE 120 can be switched from the SL BWP 750 to the next Uu BWP #2 720 indirectly. In some embodiments, the UE 120 can be switched from the SL BWP 750 to the default Uu BWP 810 at step 1240 first and then switched from the default Uu BWP 810 to the next Uu BWP #2 720 at step 1250, as shown in
At steps 1260 and 1270, the UE 120 can also be switched from the SL BWP to the next Uu BWP indirectly. For example, the UE 120 can be switched from the SL BWP 750 to the next Uu BWP #2 720 indirectly. In some embodiments, the UE 120 can be switched from the SL BWP 750 to the original Uu BWP #1 710 at step 1260 first and then switched from the original Uu BWP #1 710 to the next Uu BWP #2 720 at step 1270, as shown in
At steps 1280 and 1290, the UE 120 can also be switched from the SL BWP to the next Uu BWP indirectly. For example, the UE 120 can be switched from the SL BWP 750 to the next Uu BWP #2 720 indirectly. In some embodiments, the UE 120 can be switched from the SL BWP 750 to the default SL BWP 1110 at step 1280 first and then switched from the default SL BWP 1110 to the next Uu BWP #2 720 at step 1290, as shown in
In some embodiments, the receiving circuitry 1410 can be configured to receive wireless signals. The processing circuitry 1420 can be configured for operating on an original Uu BWP, switching from the original Uu BWP to an SL BWP, and switching from the SL BWP to the next Uu BWP. For example, the next Uu BWP is the original Uu BWP, and the processing circuitry 1420 can be configured for switching the original Uu BWP and the SL BWP to each other periodically. In some embodiments, the receiving circuitry 1410 can be configured for receiving wireless signals, e.g., a signaling. For example, the signaling can be an RRC signaling, a MAC CE, or DCI. In an embodiment, the signaling can instruct the processing circuitry 1420 to switch from the SL BWP to the original Uu BWP first and then switch from the original Uu BWP to the next Uu BWP when switching from the SL BWP to the next Uu BWP. For example, the signaling can further instruct the processing circuitry 1420 to switch from the original Uu BWP to a default Uu BWP (and switch from the default Uu BWP to the next Uu BWP) when switching from the original Uu BWP to the next Uu BWP. In another embodiment, the signaling can instruct the processing circuitry 1420 to switch from the SL BWP to a default Uu BWP (and then switch from the default Uu BWP to the next Uu BWP) when switching from the SL BWP to the next Uu BWP. In yet another embodiment, the signaling can instruct the processing circuitry 1420 to switch from the SL BWP to a default SL BWP first and then switch from the default SL BWP to the next Uu BWP when switching from the SL BWP to the next Uu BWP. In some embodiments, the signaling can be denoted by the SL timer 1430, or in other words, the SL timer 1430 can be set, and the processing circuitry 1420 can be configured for switching from the SL BWP to the next Uu BWP after the SL timer 1430 expires. In other embodiments, the signaling can be denoted by the SL timer 1430, or in other words, the SL timer 1430 can be set, and the processing circuitry 1420 can be configured for switching from the SL BWP to the default Uu BWP after the SL timer 1430 expires. In various embodiments, the signaling can be denoted by the SL timer 1430, or in other words, the SL timer 1430 can be set, and the processing circuitry 1420 can be configured for switching from the SL BWP to the original Uu BWP after the SL timer 1430 expires. In still other embodiments, the signaling can be denoted by the SL timer 1430, or in other words, the SL timer 1430 can be set, and the processing circuitry 1420 can be configured for switching from the SL BWP to the default SL BWP after the SL timer 1430 expires.
In various embodiments according to the disclosure, the receiving circuitry 1410 and the processing circuitry 1420 can include circuitry configured to perform the functions and processes described herein in combination with software or without software. In various examples, the processing circuitry can be a digital signal processor (DSP), an application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device or a combination thereof. In some other embodiments according to the disclosure, the processing circuitry 1420 can be a central processing unit (CPU) configured to execute program instructions to perform various functions and processes described herein.
The apparatuses 1400 and 1500 can optionally include other components, such as input and output devices, additional or signal processing circuitry, and the like. Accordingly, the apparatuses 1400 and 1500 may be capable of performing other additional functions, such as executing application programs, and processing alternative communication protocols.
The processes and functions described herein can be implemented as a computer program which, when executed by one or more processors, can cause the one or more processors to perform the respective processes and functions. The computer program may be stored or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with, or as part of, other hardware. The computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. For example, the computer program can be obtained and loaded into an apparatus, including obtaining the computer program through physical medium or distributed system, including, for example, from a server connected to the Internet.
The computer program may be accessible from a computer-readable medium providing program instructions for use by or in connection with a computer or any instruction execution system. The computer readable medium may include any apparatus that stores, communicates, propagates, or transports the computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable medium can be magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The computer-readable medium may include a computer-readable non-transitory storage medium such as a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a magnetic disk and an optical disk, and the like. The computer-readable non-transitory storage medium can include all types of computer readable medium, including magnetic storage medium, optical storage medium, flash medium, and solid state storage medium.
While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202010776390.7 | Aug 2020 | CN | national |
This present disclosure claims the priority of PCT/CN2019/100786, titled “CHANNEL STRUCTURE DESIGN FOR V2X COMMUNICATION” filed on Aug. 15, 2019, and Chinese Patent Application No. 202010776390.7 filed on Aug. 5, 2020, which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2019/100784 | Aug 2019 | US |
| Child | 16993780 | US |
