Managing unwanted transmissions

Aspects of the present disclosure provide techniques for managing unwanted transmissions by a wireless communications device, such as spurious transient transmissions caused by changing a power level of a transmitter. An exemplary method includes determining, based on one or more parameters, an action to reduce an impact of a spurious transmission by the UE, wherein the spurious transmission relates to at least one of changing a transmit power level at the UE or switching one or more radio components at the UE, and taking the determined action to reduce the impact.

INTRODUCTION

Aspects of the present disclosure relate to wireless communications and, more particularly, to managing unwanted transmissions by a wireless communications device, such as spurious transient transmissions caused by changing a power level of a transmitter.

A wireless communication network may include a number of Node Bs that can support communication for a number of user equipments (UEs). A UE may communicate with a Node B via the downlink and uplink. The downlink (or forward link) refers to the communication link from the Node B to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the Node B.

Any transition in a wireless modem (e.g., a wireless modem in a UE) between ‘transmitting’ and ‘not transmitting’ may cause some switching transient. Some transmission may occur in the transient, but the transmitted waveform in the transient may not be the desired waveform. Instead, the waveform may gradually transition into the desired waveform. This transient may be caused by ramp up time for various circuits (e.g., of the modem) to attain desired power levels. Such transients may also occur with a change in transmit power level of the modem. Thus transitioning to ‘transmitting’ from ‘not-transmitting’ is a special case, where one of the power levels is zero. Amplitude and duration of the transient transmission may depend on the amount of change of the power level.

SUMMARY

Techniques for managing unwanted transmissions by a wireless communications device, such as spurious transient transmissions caused by changing a power level of a transmitter, are described herein.

In an aspect, a method for wireless communication is provided. The method may be performed, for example, by a user equipment (UE). The method generally includes determining, based on one or more parameters, an action to reduce an impact of a spurious transmission by the UE, wherein the spurious transmission relates to at least one of changing a transmit power level at the UE or switching one or more radio components at the UE, and taking the determined action to reduce the impact.

In an aspect, a method for wireless communication is provided. The method may be performed, for example, by BS. The method generally includes providing an indication of one or more parameters related to reducing an impact of a spurious transmission by a user equipment (UE) to the UE, wherein the spurious transmission relates to at least one of changing a transmit power level at the UE or switching one or more radio components at the UE.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for managing unwanted transmissions by a wireless communications device, such as spurious transient transmissions caused by changing a power level of a transmitter.

New radio (NR) may refer to radios configured to operate according to a new air interface (e.g., other than Orthogonal Frequency Divisional Multiple Access (OFDMA)-based air interfaces) or fixed transport layer (e.g., other than Internet Protocol (IP)). NR may include Enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC) targeting non-backward compatible MTC techniques, and mission critical targeting ultra reliable low latency communications (URLLC). For these general topics, different techniques are considered, such as coding, low-density parity check (LDPC), and polar. NR cell may refer to a cell operating according to the new air interface or fixed transport layer. A NR Node B (e.g., 5G Node B) may correspond to one or multiple transmission reception points (TRPs).

NR cells can be configured as access cell (ACells) or data only cells (DCells). For example, the RAN (e.g., a central unit or distributed unit) can configure the cells. DCells may be cells used for carrier aggregation or dual connectivity, but not used for initial access, cell selection/reselection, or handover. In some cases DCells may not transmit synchronization signals—in some case cases DCells may transmit SS. TRPs may transmit downlink signals to UEs indicating the cell type. Based on the cell type indication, the UE may communicate with the TRP. For example, the UE may determine TRPs to consider for cell selection, access, handover, and/or measurement based on the indicated cell type.

In some cases, the UE can receive measurement configuration from the RAN. The measurement configuration information may indicate ACells or DCells for the UE to measure. The UE may monitor/detect measurement reference signals from the cells based on measurement configuration information. In some cases, the UE may blindly detect MRS. In some cases the UE may detect MRS based on MRS-IDs indicated from the RAN. The UE may report the measurement results.

Example Wireless Communications System

FIG. 1illustrates an example wireless network100in which aspects of the present disclosure may be performed. For example, the wireless network may be a new radio (NR) or a 5G network.

According to aspects, the wireless network100may be a heterogeneous numerology system, wherein UEs120within the network100may be asynchronous, have different intercarrier spacing, and/or have different cyclic prefix lengths. According to aspects a BS, such as BS110amay support different services having different service requirements. For example, the BS110amay support subframe with different subcarrier spacing. The BS110amay communicate with UE120ausing a first subcarrier spacing and may communicate with UE120busing a second subcarrier spacing. UEs120a,120bmay be configured to operate according to one or more numerologies. In the manner a network may support subframes with different subcarrier spacings.

According to aspects, the subcarrier spacing associated with the different service requirements may be scaled. As a non-limiting example, for illustrative purposes only, the subcarrier spacing may be 15 kHz, 30 kHz, 60 kHz, 120 kHz, and so on (e.g., ×1, ×2, ×4, ×8, and so on . . . ). According to another example, the subcarrier spacing may be 17.5 kHz, 35 kHz, and so on (e.g., ×1, ×2, ×3, ×4, and so on). Aspects described herein provide methods for tone allocation and resource block definition for heterogeneous numerology systems, which may be beneficial for scheduling devices and communicating with one or more devices in heterogeneous numerology systems.

As described herein, a numerology may be based, at least in part, on a subcarrier spacing and a shift in frequency. The BS110aand UE120amay communicate using tones determined using a numerology. Additionally or alternatively, the BS110aand120amay communicate using an RB defined using a numerology.

The BS110may be configured to perform the operations1800and2000and the UE120(e.g., UE120a) may be configured to perform the operations1900and2100. Furthermore, the BS110aand the UE120amay be configured to perform other aspects described herein. The BS may comprise and/or include a transmission reception point (TRP).

The system illustrated inFIG. 1may be, for example, a long term evolution (LTE) network. The wireless network100may include a number of Node Bs (e.g., eNodeBs, eNBs, 5G Node B, etc.)110and other network entities. A Node B may be a station that communicates with the UEs and may also be referred to as a base station, an access point, or a 5G Node B.

Each Node B110may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a Node B and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used.

A Node B may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.). A Node B for a macro cell may be referred to as a macro Node B. A Node B for a pico cell may be referred to as a pico Node B. A Node B for a femto cell may be referred to as a femto Node B or a home Node B. In the example shown inFIG. 1, the Node Bs110a,110band110cmay be macro Node Bs for the macro cells102a,102band102c, respectively. The Node B110xmay be a pico Node B for a pico cell102x. The Node Bs110yand110zmay be femto Node Bs for the femto cells102yand102z, respectively. A Node B may support one or multiple (e.g., three) cells.

The wireless network100may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., a Node B or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or a Node B). A relay station may also be a UE that relays transmissions for other UEs. In the example shown inFIG. 1, a relay station110rmay communicate with the Node B110aand a UE120rin order to facilitate communication between the Node B110aand the UE120r. A relay station may also be referred to as a relay Node B, a relay, etc.

The wireless network100may be a heterogeneous network that includes Node Bs of different types, e.g., macro Node Bs, pico Node Bs, femto Node Bs, relays, transmission reception points (TRPs), etc. These different types of Node Bs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless network100. For example, macro Node Bs may have a high transmit power level (e.g., 20 Watts) whereas pico Node Bs, femto Node Bs and relays may have a lower transmit power level (e.g., 1 Watt).

The wireless network100may support synchronous or asynchronous operation. For synchronous operation, the Node Bs may have similar frame timing, and transmissions from different Node Bs may be approximately aligned in time. For asynchronous operation, the Node Bs may have different frame timing, and transmissions from different Node Bs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

A network controller130may couple to a set of Node Bs and provide coordination and control for these Node Bs. The network controller130may communicate with the Node Bs110via a backhaul. The Node Bs110may also communicate with one another, e.g., directly or indirectly via wireless or wireline backhaul.

The UEs120(e.g.,120x,120y, etc.) may be dispersed throughout the wireless network100, and each UE may be stationary or mobile. A UE may also be referred to as a terminal, a mobile station, a subscriber unit, a station, etc. A UE may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a netbook, a smart book, etc. A UE may be able to communicate with macro Node Bs, pico Node Bs, femto Node Bs, relays, etc. InFIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving Node B, which is a Node B designated to serve the UE on the downlink and/or uplink. A dashed line with double arrows indicates interfering transmissions between a UE and a Node B.

While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. A single component carrier bandwidth of 100 MHZ may be supported. NR resource blocks may span 12 sub-carriers with a sub-carrier bandwidth of 75 kHz over a 0.1 ms duration. Each radio frame may consist of 50 subframes with a length of 10 ms. Consequently, each subframe may have a length of 0.2 ms. Each subframe may indicate a link direction (i.e., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells. Alternatively, NR may support a different air interface, other than an OFDM-based. NR networks may include entities such central units or distributed units.

FIG. 2shows a down link (DL) frame structure used in a telecommunication systems (e.g., LTE). The transmission timeline for the downlink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be partitioned into 10 sub-frames with indices of 0 through 9. Each sub-frame may include two slots. Each radio frame may thus include 20 slots with indices of 0 through 19. Each slot may include L symbol periods, e.g., 7 symbol periods for a normal cyclic prefix (as shown inFIG. 2) or 14 symbol periods for an extended cyclic prefix. The 2L symbol periods in each sub-frame may be assigned indices of 0 through 2L−1. The available time frequency resources may be partitioned into resource blocks. Each resource block may cover N subcarriers (e.g., 12 subcarriers) in one slot.

In LTE, a Node B may send a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) for each cell in the Node B. The primary and secondary synchronization signals may be sent in symbol periods6and5, respectively, in each of sub-frames 0 and 5 of each radio frame with the normal cyclic prefix, as shown inFIG. 2. The synchronization signals may be used by UEs for cell detection and acquisition. The Node B may send a Physical Broadcast Channel (PBCH) in symbol periods 0 to 3 in slot 1 of sub-frame 0. The PBCH may carry certain system information.

The Node B may send a Physical Control Format Indicator Channel (PCFICH) in only a portion of the first symbol period of each sub-frame, although depicted in the entire first symbol period inFIG. 2. The PCFICH may convey the number of symbol periods (M) used for control channels, where M may be equal to 1, 2 or 3 and may change from sub-frame to sub-frame. M may also be equal to 4 for a small system bandwidth, e.g., with less than 10 resource blocks. In the example shown inFIG. 2, M=3. The Node B may send a Physical HARQ Indicator Channel (PHICH) and a Physical Downlink Control Channel (PDCCH) in the first M symbol periods of each sub-frame (M=3 inFIG. 2). The PHICH may carry information to support hybrid automatic retransmission (HARQ). The PDCCH may carry information on uplink and downlink resource allocation for UEs and power control information for uplink channels. Although not shown in the first symbol period inFIG. 2, it is understood that the PDCCH and PHICH are also included in the first symbol period. Similarly, the PHICH and PDCCH are also both in the second and third symbol periods, although not shown that way inFIG. 2. The Node B may send a Physical Downlink Shared Channel (PDSCH) in the remaining symbol periods of each sub-frame. The PDSCH may carry data for UEs scheduled for data transmission on the downlink. The various signals and channels in LTE are described in 3GPP TS 36.211, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation,” which is publicly available.

A number of resource elements may be available in each symbol period. Each resource element may cover one subcarrier in one symbol period and may be used to send one modulation symbol, which may be a real or complex value. Resource elements not used for a reference signal in each symbol period may be arranged into resource element groups (REGs). Each REG may include four resource elements in one symbol period. The PCFICH may occupy four REGs, which may be spaced approximately equally across frequency, in symbol period0. The PHICH may occupy three REGs, which may be spread across frequency, in one or more configurable symbol periods. For example, the three REGs for the PHICH may all belong in symbol period0or may be spread in symbol periods0,1and2. The PDCCH may occupy 9, 18, 32 or 64 REGs, which may be selected from the available REGs, in the first M symbol periods. Only certain combinations of REGs may be allowed for the PDCCH.

A UE may be within the coverage of multiple Node Bs. One of these Node Bs may be selected to serve the UE. The serving Node B may be selected based on various criteria such as received power, path loss, signal-to-noise ratio (SNR), etc.

A UE may be assigned resource blocks310a,310bin the control section to transmit control information to a Node B. The UE may also be assigned resource blocks320a,320bin the data section to transmit data to the Node B. The UE may transmit control information in a physical UL control channel (PUCCH) on the assigned resource blocks in the control section. The UE may transmit only data or both data and control information in a physical UL shared channel (PUSCH) on the assigned resource blocks in the data section. A UL transmission may span both slots of a subframe and may hop across frequency.

FIG. 4illustrates example components of the base station110and UE120illustrated inFIG. 1, which may be used to implement aspects of the present disclosure. One or more components of the BS110and UE120may be used to practice aspects of the present disclosure. For example, antennas452, Tx/Rx222, processors466,458,464, and/or controller/processor480of the UE120and/or antennas434, processors460,420,438, and/or controller/processor440of the BS110may be used to perform the operations described herein and illustrated with reference toFIGS. 12-14. The BS110may comprise a TRP. As illustrated, the BS/TRP110and UE120may communicate using tone alignment and/or RB definition in a heterogeneous numerology system.

FIG. 4shows a block diagram of a design of a base station/Node B/TRP110and a UE120, which may be one of the base stations/Node Bs/TRPs and one of the UEs inFIG. 1. For a restricted association scenario, the base station110may be the macro Node B110cinFIG. 1, and the UE120may be the UE120y. The base station110may also be a base station of some other type. The base station110may be equipped with antennas434athrough434t, and the UE120may be equipped with antennas452athrough452r.

At the base station110, a transmit processor420may receive data from a data source412and control information from a controller/processor440. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, etc. The data may be for the PDSCH, etc. The transmit processor420may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor420may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor430may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)432athrough432t. Each modulator432may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator432may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators432athrough432tmay be transmitted via the antennas434athrough434t, respectively. The transmit processor420, TX MIMO processor430, modulators432a-432t, and antennas434a-434tmay be collectively referred to as a transmit chain of the base station.

At the UE120, the antennas452athrough452rmay receive the downlink signals from the base station110and may provide received signals to the demodulators (DEMODs)454athrough454r, respectively. Each demodulator454may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator454may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector456may obtain received symbols from all the demodulators454athrough454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor458may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE120to a data sink460, and provide decoded control information to a controller/processor480. The receive processor458, MIMO detector456, demodulators454a-454r, and antennas452a-452tmay be collectively referred to as a receive chain of the UE.

On the uplink, at the UE120, a transmit processor464may receive and process data (e.g., for the PUSCH) from a data source462and control information (e.g., for the PUCCH) from the controller/processor480. The transmit processor464may also generate reference symbols for a reference signal. The symbols from the transmit processor464may be precoded by a TX MIMO processor466if applicable, further processed by the demodulators454athrough454r(e.g., for SC-FDM, etc.), and transmitted to the base station110. The transmit processor464, TX MIMO processor466, modulators454a-454r, and antennas452a-452rmay be collectively referred to as a transmit chain of the UE. At the base station110, the uplink signals from the UE120may be received by the antennas434, processed by the modulators432, detected by a MIMO detector436if applicable, and further processed by a receive processor438to obtain decoded data and control information sent by the UE120. The receive processor438may provide the decoded data to a data sink439and the decoded control information to the controller/processor440. The receive processor438, MIMO detector436, demodulators432a-432t, and antennas434a-434tmay be collectively referred to as a receive chain of the base station.

The controllers/processors440and480may direct the operation at the base station110and the UE120, respectively. The processor440and/or other processors and modules at the base station110may perform or direct, e.g., the execution of various processes for the techniques described herein. The processor480and/or other processors and modules at the UE120may also perform or direct, e.g., the execution of the functional blocks illustrated inFIGS. 18-21, and/or other processes for the techniques described herein. The memories442and482may store data and program codes for the base station110and the UE120, respectively. A scheduler444may schedule UEs for data transmission on the downlink and/or uplink.

FIG. 6shows two exemplary subframe formats610and620for the downlink with the normal cyclic prefix. The available time frequency resources for the downlink may be partitioned into resource blocks. Each resource block may cover 12 subcarriers in one slot and may include a number of resource elements. Each resource element may cover one subcarrier in one symbol period and may be used to send one modulation symbol, which may be a real or complex value.

Subframe format610may be used for a Node B equipped with two antennas. A CRS may be transmitted from antennas0and1in symbol periods0,4,7and11. A reference signal is a signal that is known a priori by a transmitter and a receiver and may also be referred to as a pilot. A CRS is a reference signal that is specific for a cell, e.g., generated based on a cell identity (ID). InFIG. 6, for a given resource element with label Ra, a modulation symbol may be transmitted on that resource element from antenna a, and no modulation symbols may be transmitted on that resource element from other antennas. Subframe format620may be used for a Node B equipped with four antennas. A CRS may be transmitted from antennas0and1in symbol periods0,4,7and11and from antennas2and3in symbol periods1and8. For both subframe formats610and620, a CRS may be transmitted on evenly spaced subcarriers, which may be determined based on cell ID. Different Node Bs may transmit their CRSs on the same or different subcarriers, depending on their cell IDs. For both subframe formats610and620, resource elements not used for the CRS may be used to transmit data (e.g., traffic data, control data, and/or other data).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation,” which is publicly available.

The wireless network may support hybrid automatic retransmission (HARQ) for data transmission on the downlink and uplink. For HARQ, a transmitter (e.g., a Node B) may send one or more transmissions of a packet until the packet is decoded correctly by a receiver (e.g., a UE) or some other termination condition is encountered. For synchronous HARQ, all transmissions of the packet may be sent in subframes of a single interlace. For asynchronous HARQ, each transmission of the packet may be sent in any subframe.

A UE may be located within the coverage area of multiple Node Bs. One of these Node Bs may be selected to serve the UE. The serving Node B may be selected based on various criteria such as received signal strength, received signal quality, pathloss, etc. Received signal quality may be quantified by a signal-to-noise-and-interference ratio (SINR), or a reference signal received quality (RSRQ), or some other metric. The UE may operate in a dominant interference scenario in which the UE may observe high interference from one or more interfering Node Bs.

New radio (NR) may refer to radios configured to operate according a wireless standard, such as 5G (e.g. wireless network100). NR may include Enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC) targeting non-backward compatible MTC techniques, and mission critical targeting ultra reliable low latency communications (URLLC).

NR cell may refer to a cell operating according in the NR network. A NR Node B (e.g., Node B110) may correspond to one or multiple transmission reception points (TRPs). As used herein, a cell may refer to a combination of downlink (and potentially also uplink) resources. The linking between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources is indicated in the system information (SI) transmitted on the downlink resources. For example, system information can be transmitted in a physical broadcast channel (PBCH) carrying a master information block (MIB).

NR RAN architecture may include a central unit (CU) (e.g., network controller130). The CU may be an Access node controller (ANC). The CU terminates backhaul interface to RAN-CN, terminates backhaul interface to neighbor RAN node. The RAN may include a Distributed unit that may be one or more TRPs that may be connected to one or more ANCs (not shown). TRPs may advertise System Information (e.g., Global TRP ID), may include PDCP/RLC/MAC functions, may comprise one or more antenna ports, may be configured to individually (dynamic selection) or jointly (joint transmission), and may serve traffic to the UE.

Heterogeneous numerology wireless communication systems may refer to systems in which UEs may be asynchronous, have different intercarrier spacing and/or have different cyclic prefix lengths. According to aspects of the present disclosure, tones for different numerologies may be aligned. A numerology may be based on a subcarrier spacing and a tone shift. As described herein, regardless of the numerology, the tones from the heterogeneous numerology wireless systems may be frequency-aligned.

According to aspects of the present disclosure, in a beamforming system, a broadcast signal transmitted in a particular direction (e.g., from a BS) may only reach a subset of UEs or other devices. For dynamic TDD operation, a transmitter may transmit a slot or frame format indicator to indicator the slot or frame structure for the next N slots or subframes. However, multiple users (e.g., UEs, BSs) may be scheduled in the N slots or subframes, and the users may share the transmission resources (e.g., the available frequencies for the N slots or subframes) by using TDM or FDM. Those users may have different beamforming or beam pairing association(s) with a transmitter, such as an eNB or a gNB. The transmitter (e.g., a BS, an eNB, a gNB) may transmit a slot or frame format indicator in a few OFDM symbols at the beginning of the N slots or subframes. For non-beamforming systems, transmitting one such indicator (e.g., broadcast to all devices in range) may be sufficient.

FIG. 7is a diagram700showing an example of a DL-centric subframe. The DL-centric subframe may include a control portion702. The control portion702may exist in the initial or beginning portion of the DL-centric subframe. The control portion702may include various scheduling information and/or control information corresponding to various portions of the DL-centric subframe. In some configurations, the control portion702may be a physical DL control channel (PDCCH), as indicated inFIG. 7. The DL-centric subframe may also include a DL data portion704. The DL data portion704may sometimes be referred to as the payload of the DL-centric subframe. The DL data portion704may include the communication resources utilized to communicate DL data from the scheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE). In some configurations, the DL data portion704may be a physical DL shared channel (PDSCH).

The DL-centric subframe may also include a common UL portion706. The common UL portion706may sometimes be referred to as an UL burst, a common UL burst, and/or various other suitable terms. The common UL portion706may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the common UL portion706may include feedback information corresponding to the control portion702. Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information. The common UL portion706may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information. As illustrated inFIG. 7, the end of the DL data portion704may be separated in time from the beginning of the common UL portion706by a guard period708. This guard period may sometimes be referred to as a gap, a guard interval, and/or various other suitable terms. This guard period provides time for the switch-over from DL communication (e.g., reception operation by the subordinate entity (e.g., UE)) to UL communication (e.g., transmission by the subordinate entity (e.g., UE)). One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

FIG. 8is a diagram800showing an example of an UL-centric subframe. The UL-centric subframe may include a control portion802. The control portion802may exist in the initial or beginning portion of the UL-centric subframe. The control portion802inFIG. 8may be similar to the control portion described above with reference toFIG. 7. The UL-centric subframe may also include an UL data portion804. The UL data portion804may sometimes be referred to as the payload of the UL-centric subframe. The UL portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS). In some configurations, the control portion802may be a physical DL control channel (PDCCH).

As illustrated inFIG. 8, the end of the control portion802may be separated in time from the beginning of the UL data portion804by a guard period808. This time separation may sometimes be referred to as a gap, guard period, guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the scheduling entity) to UL communication (e.g., transmission by the scheduling entity). The UL-centric subframe may also include a common UL portion806. The common UL portion806inFIG. 8may be similar to the common UL portion706described above with reference toFIG. 7. The common UL portion806may additional or alternative include information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

Example Managing Unwanted Transmissions

Any transition in a wireless modem (e.g., a wireless modem in a UE) between ‘transmitting’ and ‘not transmitting’ may cause some switching transient. A transmission (e.g., a spurious transmission) may occur in the transient, but the transmitted waveform in the transient may not be the desired waveform. Instead, the waveform of the transmission in the transient may gradually transition into the desired waveform. This transmission may be caused by ramp up time for various circuits (e.g., of the modem) to attain desired power levels. Such transmissions may also occur with a change in transmit power level of the modem. Thus transitioning between ‘transmitting’ and ‘not-transmitting’ is a special case of changing a transmit power level of a modem, where one of the power levels is zero. Amplitude and duration of the transient or spurious transmission may depend on the amount of change of the power level.

As used herein, “scheduled transmitted signal” and “scheduled transmission” refer to a transmission via time and/or frequency resources that are reserved for that transmission. Thus, as used herein, “scheduled transmitted signal” and “scheduled transmission” refer to both transmissions made in response to scheduling grants (e.g., received by a UE from a BS either dynamically or semi-statically, for either control or data transmission) and grant-free transmissions made via reserved time and/or frequency resources (e.g., RACH transmissions by a UE).

According to aspects of the present disclosure, timing of a transient or spurious transmission may be controlled to reduce a potential impact of the transient or spurious transmission. For example, if a spurious transmission is located within a period of a desired or scheduled transmitted signal, then the spurious transmission may contribute some distortion to the desired or scheduled transmitted signal and may cause an increase in an error vector magnitude (EVM) of the desired or scheduled transmitted signal. In a second example, if a spurious transmission is located outside of a period of a desired or scheduled transmit signal, then the spurious transmission may occur during a guard period, if the communications system uses guard periods, and the spurious transmission may not cause any harm (e.g., by increasing EVM of the desired or scheduled signal or interfering with other signals). However, guard periods are not always available, due to the communications system not using guard periods, or a device being required to make consecutive transmissions at differing power levels. If the spurious transmission does not occur during a guard period, then the transient or spurious transmission occurs in a time period adjacent to the time period of the desired or scheduled transmission and may interfere with other ‘legitimate’ (e.g., desired or scheduled) transmissions and/or receptions by the same or by other modems (e.g., in the same device or other devices) in the wireless communications system that are scheduled to transmit and/or receive in those adjacent time periods.

According to aspects of the present disclosure, techniques for reducing or mitigating the impact of the above described transient transmissions and/or other spurious transmissions are provided.

FIGS. 9A-9Cillustrate exemplary transmission timelines900,920, and950, according to aspects of the present disclosure. In the exemplary timeline900, an exemplary ideal waveform904is transmitted in a transmission time interval (TTI)902by an idealized transmitter. It may be noted that the idealized transmitter does not transmit outside of the TTI902in the exemplary timeline900.

In the exemplary timeline920shown inFIG. 9B, an exemplary waveform924is transmitted by an exemplary transmitter (e.g., a transmitter in UE120, shown inFIGS. 1 and 4) in the TTI902. The exemplary transmitter makes a spurious transmission922before the TTI902, for example, when various components of the transmitter are ramping up to a desired power level. It may be noted that the waveform924is similar to the waveform904, shown inFIG. 9A, but the transmitter transmits the spurious transmission922outside of the TTI.

In the exemplary timeline950shown inFIG. 9C, an exemplary waveform954is transmitted by an exemplary transmitter (e.g., a transmitter in UE120, shown inFIGS. 1 and 4) in the TTI902. The exemplary transmitter makes a spurious transmission952during the TTI902, for example, when various components of the transmitter are ramping up to a desired power level. It may be noted that the waveform954differs from the waveform904, shown inFIG. 9A, due to the spurious transmission952, but the transmitter does not transmit outside of the TTI.

FIG. 10illustrates example operations1000for wireless communications that may be performed by a UE, according to aspects of the present disclosure. The UE may be UE120a, shown inFIG. 1, which may include one or more components illustrated inFIG. 4.

Operations1000begin at block1002with the UE determining, based on one or more parameters, an action to reduce an impact of a spurious transmission by the UE, wherein the spurious transmission relates to at least one of changing a transmit power level at the UE or switching one or more radio components at the UE. For example, UE120adetermines to power up transmitter components of the UE in a period before making a scheduled transmission to reduce the impact of a spurious transmission, related to powering up the transmitter components, on the scheduled transmission by the UE. In the example, the UE determines to cause the spurious transmission to occur outside of a period for the scheduled transmission, similar to the timeline920, shown inFIG. 9B.

At block1004, operations1000continue with the UE taking the determined action to reduce the impact. Continuing the example from above, the UE powers up transmitter components before the beginning of the period for the scheduled transmission.

FIG. 11illustrates example operations1100for wireless communications that may be performed by a BS, according to aspects of the present disclosure. The BS may be BS110ashown inFIG. 1, which may include one or more components illustrated inFIG. 4.

Operations1100begin at block1102with the BS providing an indication of one or more parameters related to reducing an impact of a spurious transmission by a user equipment (UE) to the UE, wherein the spurious transmission relates to at least one of changing a transmit power level at the UE or switching one or more radio components at the UE. For example, BS110amay provide an indication of a priority of a scheduled transmission by UE120ato the UE, wherein the spurious transmission relates to at least one of a changing a transmit power level at the UE or switching one or more radio components at the UE. In the example, the UE may use the priority to determine when to power up transmitter components of the UE to reduce the impact of a spurious transmission from the UE related to powering up the transmitter components.

According to aspects of the present disclosure, a device (e.g., a UE) may take actions to reduce or mitigate impact of a spurious transmission by the device based on a priority, relative to another signal or signals (e.g., transmissions from other devices), of a scheduled (e.g., desired) transmission related to (e.g., causing) the spurious transmission by the device. The period (e.g., a transmission time interval (TTI)) that is interfered with by the spurious transmission may be used for different types of transmissions. For example, on some occasions the period may be used for a data channel, on other occasions the period may be used for a control channel, a DMRS, or a pilot, or occasionally the period may not be used for any other signals.

In aspects of the present disclosure, relative priority between the scheduled transmission (related to the spurious transmission) and the other signal(s) may vary. The relative “priority” referred to indicates an importance to system operation that the scheduled transmission occur as accurately as possible (e.g., how close to desired waveform, how low is an associated EVM) and free from interference as compared to an importance to system operation that the other signal(s) occur as accurately as possible and free from interference. For example, an OFDM symbol conveying a DMRS or a pilot transmission may have a higher priority than an OFDM symbol conveying a data transmission, especially if there is a single DMRS (e.g., in the OFDM symbol) that serves as a pilot for several data OFDM symbols.

According to aspects of the present disclosure, other pilots, such as sounding pilots (e.g., SRS, CSI-RS, and MRS) may also have higher a priority than data signals.

In aspects of the present disclosure, a device (e.g., a UE) may dynamically select an action to take to reduce an impact of the spurious (e.g., transient) transmission, depending on this relative priority:

According to aspects of the present disclosure, if a spurious transmission will interfere with higher priority transmissions, then the device may take steps to cause the spurious transmission to be within a period of the transmission by the device, so as not to interfere with the higher priority transmissions.

In aspects of the present disclosure, if a spurious transmission will interfere with lower priority signals, then the device may take steps to cause the spurious transmission to be within a period outside of a period of transmission by the device. Taking these steps may improve a quality of the transmission by the device, at the expense of worsening interference to the lower priority signals.

According to aspects of the present disclosure, information on priority for spurious transmissions may be signaled by, for example, a base station (BS).

In aspects of the present disclosure, a BS may provide to a UE priority information for transmissions immediately before and after a transmission scheduled for the UE (e.g., a transmission by the UE). For example, a BS may signal to a UE priority information for transmissions immediately before and after a transmission by the UE as part of an uplink assignment (e.g., in a PDCCH) that causes the UE to send the transmission.

According to aspects of the present disclosure, a BS may provide priority information for transmissions immediately before and after a transmission by a UE explicitly in an assignment grant. As used herein, an “assignment grant” may refer to a grant conveyed in a downlink control information (DCI), a medium access control control element (MAC-CE), a master information block (MIB) a system information block (SIB), or via radio resource control (RRC) signaling.

In aspects of the present disclosure, a BS may provide to a UE priority information for signals immediately before and after a transmission by the UE implicitly by sending a control signal carrying an assignment grant in a time and/or frequency location that indicates the priority information to the UE. For example, a BS may provide priority information for a transmission by sending a control signal carrying an assignment grant at a time such that the slot or subframe index in which the control signal is located indicates the priority information.

According to aspects of the present disclosure, a BS may provide priority information for signals immediately before and after a transmission by a UE implicitly by scheduling the transmission by the UE adjacent to a time of a known signal (e.g., with a known priority. For example, every 4th slot index may be known to a BS to carry a known type of transmission (e.g., SRS) at a certain time location within the slot, and the BS may provide this information to a UE via RRC configuration and/or signaling. In the example, the BS implicitly indicates the priority of a scheduled transmission by the UE by scheduling the transmission adjacent to a period of the known transmission.

In aspects of the present disclosure, priority information may be signaled (e.g., by a BS) in different formats. For example, priority information may indicate the nature (e.g., type) of a signal (e.g., SRS, DMRS, or data) in an adjacent period.

According to aspects of the present disclosure, relative priorities between types of signals may be indicated (e.g., signaled by a BS) in advance of a scheduled transmission in a configuration (e.g., in an RRC configuration, in a MIB and/or SIBs, or via a table in a wireless communications specification).

In aspects of the present disclosure, priority information may be signaled (e.g., by a BS), in an index directly conveying the priority level. For example, a BS may transmit a DCI indicating a scheduled transmission is higher priority than signals immediately before the scheduled transmission.

According to aspects of the present disclosure, an index of a priority level may indicate more than two (e.g., high and low) priorities. A difference between the indices of a scheduled transmission by a UE and a signal in an adjacent period may indicate to what extent the UE may let a spurious transmission associated with the scheduled transmission overlap with the signal in the adjacent period.

In aspects of the present disclosure, actions taken to reduce impact of spurious transmissions may be affected by a plurality of factors in addition to priority levels.

According to aspects of the present disclosure, actions taken to reduce impact of spurious transmissions may depend on ordering of signals. That is, which signal has higher priority may depend on which signal is transmitted earlier. The strength of the spurious or transient transmission may be different at the beginning of the transmission as compared to at the end of the transmission, and the priority determination may take this into account.

In aspects of the present disclosure, actions taken to reduce impact of spurious transmissions may depend on instantaneous signal powers of a scheduled transmission and other signals (e.g., signals in periods adjacent to a period of the scheduled transmission). For example, in some situations a lower priority signal may be required to not overlap with a higher priority signal for certain combinations of power levels of the two signals, but the signals may be allowed to overlap for certain other power level combinations.

According to aspects of the present disclosure, power-level thresholds for determining actions to take to reduce impact of spurious transmissions may be configured.

In aspects of the present disclosure, a scheduled transmission (e.g., with a related spurious transmission) and the other signal (e.g., that may be interfered with by the spurious transmission) may not be transmissions between different transmitters and/or receivers or via different transmission links. For example, two transmissions in adjacent periods from the same transmitter to the same receiver, but of different types and power levels (e.g., SRS followed by DMRS) may also cause spurious transmissions, and actions may be taken to reduce an impact of the spurious transmissions.

According to aspects of the present disclosure, priority level and actions taken to reduce impact of spurious transmissions may be different, depending on whether or not the contending signals have a same transmitter and/or receiver, or a conveyed via different transmission links.

It may be noted that in the case of transmissions via a same transmission link, there is no additional overhead consumed to signal the nature of the signal with which the spurious transmission may interfere, as both transmissions comes from the same device, which can determine the nature of the signals.

In aspects of the present disclosure, a switching gap or guard period may be treated as a special case of priority indication.

According to aspects of the present disclosure, NR supports mini-slot transmission, where a mini-slot comprises N OFDM symbols, and N is less than the defined number of OFDM symbols in a slot (e.g., seven). A mini-slot may span across slot boundaries.

In aspects of the present disclosure, mini-slots occurring immediately before or immediately after a DL to UL switch may have an associated guard time for the switching. Spurious transmissions may be moved into the guard time without impacting other signals. However, if a UE only knows a start and end time of a mini-slot that has been allocated to the UE for a transmission, the UE may not know whether or not that mini-slot is preceded and/or followed by a guard period.

According to aspects of the present disclosure, additional signaling may be used to inform a UE about presence or absence of guard periods immediately before and/or after a mini-slot in which the UE has been scheduled to transmit.

In aspects of the present disclosure, a guard period may be treated as a type of transmission having the least possible priority and lower than a priority of any other actual signal of interest. For example, a UE may be configured with to treat all guard periods with a priority of −1, while a BS serving the UE may indicate priorities of transmissions and signals as either0or1, so that the UE will treat all transmissions as having a higher priority that a guard period.

According to aspects of the present disclosure, beamforming may be used to reduce an impact of a spurious transmission.

In aspects of the present disclosure, in systems using beamforming, for example, millimeter wave systems, when a spurious transmission related to a scheduled transmission may interfere with signals in time-slots adjacent to a time-slot of the scheduled transmission, beams may be used to transmit the spurious transmission that are different from beams used to transmit the actual signal of interest. The signal of interest may be beamformed so as to reach its intended receiver as strongly as possible. The beam used to transmit the signal of interest may be selected, optimized, and updated, based on beam training and/or beam management procedures.

According to aspects of the present disclosure, the spurious transmission may be beamformed so as to cause minimal interference to all receivers of the signals in the adjacent time durations which the spurious transmission will overlap. Undesired beams (e.g., beams that are weakly received by the intended receiver and are weaker interferers than other beams) identified during beam training and/or management may be used for the spurious transmission. These undesired beams may also be updated by beam management. If the undesired beams start becoming stronger interferers, then a new undesired beam may be found (e.g., by reference to previous beam training or performing a new beam training operation) and used for spurious transmissions. The UE may autonomously find new undesired beams, or the base station may signal new undesired beams to the UE. The base station may coordinate with neighboring base stations to determine the undesired beams, so as to ensure that the undesired beams used for spurious transmissions are received weakly at all the receivers in the neighboring cells as well. In particular, with dynamic TDD operation, the neighboring cells could be sending downlink traffic, and the receivers being interfered with in those cells would then be UEs, rather than base stations. This may make it more difficult to determine an appropriate undesired beam. So the base station may coordinate with the neighboring base stations to schedule transmissions to reduce the frequency of such occurrences, for example, when the spurious transmissions are known to be particularly strong, or for UEs (e.g., both UEs transmitting spurious transmissions and UEs being interfered with) near the cell edge.

In aspects of the present disclosure, both the technique of shifting a spurious transmission in time based on relative priority of a related scheduled transmission and the technique of using beamforming to reduce an impact of a spurious transmission may be combined.

According to aspects of the present disclosure, the technique of shifting a spurious transmission in time based on relative priority of a related scheduled transmission and the technique of using beamforming may also influence each other. For example, a transmission deemed as high priority (e.g., disallowing any interfering spurious transmission) without beamforming may be revised to a lower priority that allows some interfering spurious transmissions, if it is known that the impact of those spurious transmissions can be mitigated by beamforming the spurious transmissions to use an undesired (e.g., weakly received by an intended receiver of the high priority transmission) beam.

In aspects of the present disclosure, the technique of shifting a spurious transmission in time based on relative priority of a related scheduled transmission and the technique of using beamforming may also be used with other spurious emissions. For example, an RF calibration procedure (e.g. by a UE calibrating a receiver of the UE) may involve transmitting some known test signals by a device. Test signal transmissions for the RF calibration procedure can be scheduled by the network, and may partially overlap with other signals based on priority levels of the other signals and the test signal transmissions. When overlapping, impact of the test signal transmission can be reduced by beamforming the test signals to use weak transmissions, as described above. Alternatively, the UE may autonomously transmit the test signals with sufficiently low power and a suitable beamforming so that the test signals cause a lower amount of interference. The power levels and beamforming pattern or weights may be determined by the UE or signaled to the UE by the base station, as described above.

Thus, certain aspects may comprise a computer program product/computer readable medium for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein.