Radar management based on interference detected over an air interface

Certain aspects of the present disclosure provide techniques for radar management based on interference detected over an air interface. A method that may be performed by a base station (BS) or a user equipment (UE) includes measuring received power at each of a plurality of receive-beams. The method may also include determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. If the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the method may also include selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmitting a radar waveform over the directional transmit beam.

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for radar management based on interference detected over an air interface.

Description of Related Art

SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include an improved ability to detect an object while maintaining wireless communications between multiple network entities.

Certain aspects provide a method for detecting interference by a network entity. The method generally includes measuring received power at each of a plurality of receive-beams. The method may also include determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. If the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the method may also include selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmitting a radar waveform over the directional transmit beam.

Certain aspects provide a network entity configured to detect interference over an air interface, comprising a memory and a processor, wherein the processor is communicatively coupled to the memory. In certain aspects, the processor is configured to measure received power at each of a plurality of receive-beams. In certain aspects, the processor is configured to determine whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. In certain aspects, if the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the processor is configured to select a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmit a radar waveform over the directional transmit beam.

Certain aspects provide an apparatus for detecting interference. In some examples, the apparatus includes means for measuring received power at each of a plurality of receive-beams. In some examples, the apparatus includes means for determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. In some examples, the apparatus includes means for selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and means for transmitting a radar waveform over the directional transmit beam, if the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition.

A non-transitory computer readable storage medium that stores instructions that when executed by a processor of an apparatus cause the apparatus to perform a method of detecting interference over an air interface. In some examples, the non-transitory computer readable storage medium includes measuring received power at each of a plurality of receive-beams. In some examples, the non-transitory computer readable storage medium includes determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. In some examples, the non-transitory computer readable storage medium includes selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmitting a radar waveform over the directional transmit beam, if the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for detecting and measuring interference over an air interface (e.g., radio transmission interface for wireless communications), and managing transmission of a radar waveform based on an amount of interference detected. For example, if a network entity measures a relatively high level (e.g., greater than a threshold value) of interference over an air interface, the network entity may determine not to transmit the radar waveform because the radar waveform may jam or interfere with signaling from other network entities. However, if the network entity measures a relatively low level (e.g., less than a threshold value) of interference over an air interface, the network entity may determine to transmit the radar waveform in order to detect whether an object or individual is within a range of the network entity.

In some examples, the network entity receives and measures an amount of power or a rise over thermal (RoT) based on signals received over a plurality of directional receive beams. In some examples, the network entity may include a base station (BS).

FIG. 1illustrates an example wireless communication network100in which aspects of the present disclosure may be performed. For example, the wireless communication network100may be an NR system (e.g., a 5G NR network).

According to certain aspects, BSs110may be configured for managing radar transmissions. As shown inFIG. 1, the BS110aincludes a radar manager112. The radar manager112may be configured to measure received power at each of a plurality of receive-beams, in accordance with aspects of the present disclosure. In some examples, the radar manager112may determine whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. If the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the radar manager112may be configured to select a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmit a radar waveform over the directional transmit beam.

According to certain aspects, the UEs120may be configured for managing radar transmissions. As shown inFIG. 1, UE120aincludes a radar manager113. The radar manager113may be configured to measure received power at each of a plurality of receive-beams, in accordance with aspects of the present disclosure. In some examples, the radar manager113may determine whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. If the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the radar manager113may be configured to select a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmit a radar waveform over the directional transmit beam.

Wireless communication network100may also include relay stations (e.g., relay station110r), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS110aor a UE120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE120or a BS110), or that relays transmissions between UEs120, to facilitate communication between devices.

A network controller130may couple to a set of BSs110and provide coordination and control for these BSs110. The network controller130may communicate with the BSs110via a backhaul. The BSs110may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

FIG. 2illustrates example components200of BS110aand UE120a(e.g., in the wireless communication network100ofFIG. 1), which may be used to implement aspects of the present disclosure.

In a MIMO system, the BS110aand the UE120ainclude multiple antennas (234athrough234tand252athrough252r) to generate a plurality of signal paths between the UE120aand the BS110a. The use of such multiple antenna technology enables the wireless communication system to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data, also referred to as layers, simultaneously on the same time-frequency resource. The data streams may be transmitted to a single UE to increase the data rate or to multiple UEs to increase the overall system capacity, the latter being referred to as multi-user MIMO (MU-MIMO). This is achieved by spatially precoding each data stream (i.e., multiplying the data streams with different weighting and phase shifting) and then transmitting each spatially precoded stream through multiple transmit antennas on the DL. The spatially precoded data streams arrive at the UE(s) with different spatial signatures, which enables each of the UE(s) to recover the one or more data streams destined for that UE. On the UL, each UE transmits a spatially precoded data stream, which enables the base station to identify the source of each spatially precoded data stream.

At the BS110a, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. The processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor220may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor230may 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) in transceivers232a-232t. Each modulator may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators of transceivers232a-232tmay be transmitted via the antennas234a-234t, respectively.

The memories242and282may store data and program codes for BS110aand UE120a, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

As shown inFIG. 2, the controller/processor240of the BS110ahas a radar manager112that may be configured for managing radar transmissions from the BS110a. For example, the radar manager112may be configured to measure received power at each of a plurality of receive-beams, in accordance with aspects of the present disclosure. In some examples, the radar manager112may determine whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. If the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the radar manager112may be configured to select a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmit a radar waveform over the directional transmit beam.

Similarly, the controller/processor280of the UE120ahas a radar manager113that may be configured for managing radar transmissions from the UE120a. For example, the radar manager113may be configured to measure received power at each of a plurality of receive-beams, in accordance with aspects of the present disclosure. In some examples, the radar manager113may determine whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition. If the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the radar manager113may be configured to select a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition, and transmit a radar waveform over the directional transmit beam.

FIG. 3is a diagram showing an example of a frame format300for NR. The transmission timeline for each of a downlink and an uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each of 1 ms, with indices of 0 through 9. Each subframe may include a variable number of slots depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods in each slot may be assigned indices. A mini-slot is a subslot structure (e.g., 2, 3, or 4 symbols).

In NR, a synchronization signal (SS) block (SSB) is transmitted. The SS block includes a PSS, a SSS, and a two symbol PBCH. The SS block can be transmitted in a fixed slot location, such as the symbols0-3as shown inFIG. 3. The PSS and SSS may be used by UEs for cell search and acquisition. The PSS may provide half-frame timing, and the SS may provide the CP length and frame timing. The PSS and SSS may provide the cell identity. The PBCH carries some basic system information, such as downlink system bandwidth, timing information within radio frame, SS burst set periodicity, system frame number, etc. The SS blocks may be organized into SS bursts to support beam sweeping. Further system information such as, remaining minimum system information (RMSI), system information blocks (SIBs), other system information (OSI) can be transmitted on a physical downlink shared channel (PDSCH) in certain subframes.

In some examples of wireless communication, an electronic device (e.g., a UE120and/or BS110a) may use a high transmit power to compensate for path loss associated with millimeter wave (mmW) signals. Many of these electronic devices can be physically operated by a user. Such physical proximity presents opportunities for radiation to exceed a given guideline, such as a maximum permitted exposure (MPE) limit as determined by the Federal Communications Commission (FCC). Because of these issues, it is advantageous to enable devices to detect proximity of objects (e.g., the user).

Some proximity-detection techniques may use a dedicated sensor to detect the user, such as a camera, an infrared sensor, or a radar sensor. However, many such sensors are bulky and expensive. Furthermore, a single electronic device can include multiple antennas that are positioned on different surfaces (e.g., on a top, a bottom, or opposite sides). To account for each of these antennas, multiple cameras or sensors may need to be installed near each of these antennas, which further increase cost and size of the electronic device.

Thus, in some examples, the electronic device may use a wireless transceiver to perform both radar proximity detection and wireless communication, instead of additional cameras or sensors. For example, a local oscillator circuit within the wireless transceiver can generate one or more reference signals that enable both proximity detection and wireless communication. By actively measuring a range to an object, a surrounding environment can be continually monitored and the transmission parameter can be adjusted to account for movement by the object, enabling the wireless transceiver to meet guidelines promulgated by the government or the wireless industry, such as the MPE.

In some examples, an electronic device can transmit a radar waveform during one or more slots of a radio frame, for example, during a slot reserved for a random access channel (RACH) procedure. As such, the electronic device can periodically perform radar proximity detection during certain RACH slots. However, because the radar proximity detection necessarily requires simultaneous transmission and reception, uplink RACH transmissions from other electronic devices can jam the radar detector and reduce the effectivity of proximity-detection. Thus, methods for detecting and avoiding signaling from other electronic devices would enhance the electronics device's ability to actively detect objects and adjust transmission of mmW signals to meet safety guidelines promulgated by the government or the wireless industry.

Example Radar Transmissions

Radio detection and ranging (radar) is a complementary technology to wireless communication, and can be utilized to enhance public safety and the wireless communication experience. Radar uses electromagnetic waveforms to detect objects and determine information such as its relative speed and location. As noted above, radar can be used to enhance public safety.

FIG. 4is a diagram illustrating a communication network400utilizing a radar waveform and uplink wireless communication signaling.FIG. 4shows a wireless communication device402(e.g., user equipment (UE)120aor base station (BS)110aofFIGS. 1 and 2) performing radar proximity detection by transmitting a radar waveform408and receiving the reflection of the waveform off of an object404.FIG. 4also shows the wireless communication device402receiving or detecting an uplink signal410transmitted from a UE406for, in one example, initiating a RACH procedure. In some examples, the UE406may be a UE120shown inFIG. 1.

For a stationary ranging radar system (e.g., a radar system on the wireless communication device402), distance (D)=½ the time delay between the transmitted and received radar waveform times the speed of the radar waveform (which may be approximated as 3×108m/s or (C)). Transmitters and receivers (e.g., transceivers232a-232tor254a-254rofFIG. 2) can use the same antenna, or groups of antennas (e.g., antennas234a-234tor252a-252rofFIG. 2), and use circuitry such as a duplexer to control input and output operation. In certain aspects, it is impractical to use single pulse radar systems, as it will be appreciated that for a ten meter target, the time delay is less than 1/10 of a microsecond [(2*10)/(3*108)=66 nanoseconds]. Thus, another approach to radar detection is to use a continuous wave (CW) radar waveform.

Unmodulated CW (UM-CW) radar detection systems transmit a radar waveform at a constant frequency and use any change in frequency in the received radar waveform to determine the speed of an object. UM-CW radar is not typically used to provide range as stationary objects do not generate a frequency change in the received radar waveform. UM-CW radar is commonly used in sports, for example to determine the speed of a baseball or a racecar.

To obtain more information, frequency modulated CW (FM-CW) radar may be used. In general, a frequency of the FM-CW signal (e.g., radar waveform408ofFIG. 4) increases or decreases across a time interval. Different types of frequency modulations may be used, including linear-frequency modulations (LFM) (e.g., chirp), sawtooth-frequency modulations, triangular-frequency modulations, and so forth. The FM-CW signal can be generated using existing components within the wireless transceiver232a-232tor254a-254r. The FM-CW signal enables radar-based ranging techniques to be utilized to determine the range to an object404. To achieve a finer range resolution (e.g., on the order of centimeters (cm)) for close-range applications, larger bandwidths can be utilized, such as 1 gigahertz (GHz), 4 GHz, 8 GHz, and so forth. For instance, the FM-CW signal can have a bandwidth of approximately 4 GHz and include frequencies between approximately 26 and 30 GHz. The finer range resolution improves range accuracy and enables one or more objects404to be distinguished in range. The FM-CW signal can provide an accurate range measurement for a variety of distances based on the bandwidth (e.g., between approximately 4 and 20 cm for a 4 GHz bandwidth). While the FM-CW signal can be used to measure significant ranges, it should be noted that the FM-CW signal can measure ranges between approximately 0 and 150 cm. An amount of time for performing proximity detection can also be relatively short using the FM-CW signal, such as within approximately one microsecond.

The wireless communication device402may be configured to utilize the radar waveform408to detect the presence of an object404(e.g., human) up to 150 cm from the wireless communication device402. The wireless communication device402may perform the object404detection process to determine an appropriate transmit power that depend on whether an object404is detected, and the proximity of a detected object to the wireless communication device402. In the case that the wireless communication device404is a BS (e.g., BS110a), the BS110amay be configured to have a maximum permitted exposure (MPE) range of 150 cm from a radiating element (e.g., antenna234a-234t) for transmitting at 55 dBm. That is, the BS110amay be configured to detect a proximity of an object404relative to the BS110a, and if the object is within 150 cm of the radiating element, the BS110awill not transmit over 55 dBm.

Similarly, in the case that the wireless communication device404is a UE (e.g., UE120a), the UE120amay be configured to have a maximum permitted exposure (MPE) range of 15 cm from a radiating element (e.g., antenna252a-252r) for transmitting at 32 dBm. That is, the UE120amay be configured to detect a proximity of an object404relative to the UE120a, and if the object is within 15 cm of the radiating element, the UE120awill not transmit over 32 dBm.

FIG. 5Adepicts three FM-CW radar waveforms (or chirps) on a frequency-time scale. Chirp502has a first slope with its frequency originating at (Fc) of zero (or zero offset). Chirp504has the same slope as chirp502and a positive (Fc) offset. Chirp506has a zero offset and a second slope that is lower than the first slope of chirp502(lower frequency delta for the same time delta).

FIG. 5Bdepicts chirp502fromFIG. 5Aon an amplitude-time scale wherein the amplitude (Ac) oscillations increase in frequency over the chirp time. It will be appreciated that in certain aspects, the phase of the chirp may be controlled to provide a desired phase. When an FM-CW chirp is received, it may experience both a change in frequency and a time delay, and therefore can be used to simultaneously measure the relative range (e.g., using the time delay) and the velocity (e.g., using the frequency change) of an object from the radar detection system.

FIG. 6shows two graphs600representative of an object detected by one or more radar waveforms. Radar waveform602depicts detecting an object with a single chirp in an environment free from interference. The signal-to-noise ratio is ideal as the noise is shown as zero. It will be appreciated that environments are rarely free from interference. For example, radar waveform604depicts detecting an object with a single chirp in an environment with relatively high interference and/or high powered signaling from other sources. For example, if the wireless communication device402ofFIG. 4receives the radar waveform408reflection indicating the object404signaling at the same time the UE406transmits an uplink signal, the radar waveform408reflection may appear similar to the radar waveform604. It will be appreciated that the signal to noise ratio is poor because the interference is high making object detection poor. Such environments may impede object detection, and/or jam the radar waveform.

Example Radar-Based Target Detection and Interference Avoidance

FIG. 7is a block diagram illustrating an example of using receive-beam beamforming for noise measurement prior to performing radar proximity detection by a BS (e.g., BS110aofFIGS. 1 and 2) or a UE (e.g., UE120aofFIG. 1).FIG. 7shows a series of contiguous slots702(e.g., similar to the slots illustrated inFIG. 3) used for wireless communication over an air interface between the BS and the UE.

In certain aspects, the series of slots702may be communicated using a TDD carrier. As such, the series of slots702may include a series of uplink and downlink slots, as well as a periodic random access channel (RACH) slot704. The RACH is a shared channel that may be used by the BS110aand UE120ato initiate access to a mobile network (e.g., TDMA/FDMA, and CDMA based network) for call set-up and data transmission. In certain aspects, the BS110aor UE120amay utilize the RACH slot704to measure noise and received power over the air interface, as well as to transmit a radar waveform and receive a reflection of the radar waveform.

As noted above, a slot may include a number of symbol periods. In this example, the RACH slot704includes a set of symbols706having 14 symbols. In certain aspects, the BS110amay dedicate a variable number of symbols in the beginning of the set of symbols706of the RACH slot704to measuring noise and/or power in the air interface in various directions. For example, the BS110aor UE120amay utilize a plurality of receive-beams (708,710,712) to measure power received at each beam, wherein the direction of each receive-beam is different than other beams in the plurality of receive-beams (708,710,712). In some examples, each receive-beam includes a beam ID (e.g., BeamID1, BeamID2, BeamID3) indicative of the direction of the beam.

For example, the BS110aor UE120amay receive and measure power from the plurality of directional receive-beams (708,710,712) at the beginning of the RACH slot704, wherein each of the plurality of receive-beams (708,710,712) has a beam ID (e.g., BeamID1, BeamID2, BeamID3) and is characterized by an azimuth angle offset relative to the other receive-beams. As shown inFIG. 7, a first receive-beam708(BeamID1) is generated by the BS110aor UE120aduring a first two contiguous symbols (e.g., symbols0and1) of the RACH slot having a duration of T1. The BS110aor UE120amay configure the first receive-beam708so that the direction of the beam is directed at a zero degree (0°) perpendicular angle relative to the transceiver generating the beam. Following the first receive-beam708, the BS110aor UE120amay generate a second receive-beam710(BeamID2) during a second two contiguous symbols (e.g., symbols2and3) of the RACH slot704having a duration of T2. The BS110aor UE120amay configure the second receive-beam710so that the direction of the beam is at a forty-five degree (45°) azimuth angle relative to the first receive-beam708. Then, following the second receive-beam710, the BS110aor UE120amay generate a third receive-beam712(BeamID3) during a third two contiguous symbols (e.g., symbols4and5) of the RACH slot having a duration of T3. The BS110aor UE120amay configure the first receive-beam so that the direction of the beam is at a negative forty-five degree)(−45° azimuth angle relative to the first receive-beam. It should be noted that the BS110aor UE120amay use any suitable angle for directing the plurality of receive-beams (708,710,712).

During the time that the BS110aor UE120ais generating the receive-beams (708,710,712), the BS110aor UE120amay be configuring a local oscillator (LO) circuit (e.g., an LO circuit in one or more of transceivers232a-232tor254a-254rofFIG. 2) for transmission of a radar waveform714.

In certain aspects, the BS110aor UE120amay measure received power and calculate a rise over thermal (RoT) for each of the plurality of receive-beams (708,710,712). In this example, the BS110aor UE120ameasures the received power at each of the plurality of receive-beams during the RACH slot704, wherein each of the plurality of receive-beams is measured contiguously (e.g., in series) and for a duration of at least two symbols. The BS110aor UE120ameasures power corresponding to interference, or noise, in the air interface, as well as potentially signaling from other network entities (e.g., UE120and/or BS110) in the vicinity. For example, if another UE120attempts to initiate a RACH procedure for establishing a cell connection with the BS110aduring the RACH slot704, the BS110aor UE120amay measure a relatively high level of power from one or more of the plurality of receive-beams (708,710,712) if one or more of the beams intercept a RACH preamble (Msg 1) transmitted by the other UE120.

The BS110aor UE120amay then calculate the RoT for each of the plurality of receive-beams (708,710,712) based on the measured power associated with each beam and a configurable baseline noise power value stored on the BS110aor UE120a. In some examples, the RoT may represent a power-to-interference ratio calculated using the following equation:

R⁢o⁢Tx=Rx⁢P⁢w⁢rN⁢o⁢i⁢s⁢e⁢P⁢w⁢rEquation⁢⁢1
Where RxPwr corresponds to the measured power of one of the plurality of beams (708,710,712), where x identifies which of the plurality of beams the measurement corresponds to, and where NoisePwr corresponds to the configurable baseline noise power value stored on the BS110aor UE120a.

In some examples, the baseline noise-power value indicates a ceiling power or noise level in the air interface that the BS110aor UE120acan tolerate for purposes of transmitting a radar waveform and receiving a reflection of the waveform. In such an example, the calculated RoT may indicate whether the measured power of each of the plurality of receive-beams satisfies a threshold condition. For example, if the RoT value of one of the receive-beams (708,710,712) is greater than 1 (e.g., a configurable number such as 10, or any number greater than 2), the BS110aor UE120amay determine that the threshold condition is not satisfied because the measured power is greater than the baseline noise-power value. In this example, the BS110aor UE120amay determine not to transmit a radar waveform in the same direction as that receive-beam. Instead, the BS110aor UE120amay determine to transmit the radar waveform in a same direction as another receive-beam having an RoT value that is close to 1 (e.g., an RoT value between 1 and 2). Alternatively, if the RoT value of one of the receive-beams (708,710,712) is close to 1 (e.g., an RoT value between 1 and 2), the BS110aor UE120amay determine that the threshold condition is satisfied because the measured power is within range of the baseline noise-power value. In this example, the BS110aor UE120amay determine to transmit a radar waveform in the same direction as that receive-beam.

Accordingly, if the measured power received at one or more of the plurality of receive-beams (708,710,712) satisfies the threshold condition, then the BS110aor UE120amay select a convenient directional transmit beam with low interference relative to other beams in the plurality of receive-beams (708,710,712), where the direction of the transmit beam is based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition. In certain aspects, the BS110aor UE120aselects the directional transmit beam by determining which of the plurality of receive-beams is associated with the lowest measured power relative to the other of the plurality of receive-beams (708,710,712). For example, if the first receive-beam708has one or more of the lowest calculated RoT or the lowest measured power relative to the other receive-beams, then the BS110aor UE120amay select a directional transmit beam for transmitting the radar waveform, wherein the direction of the transmit beam is the same as the direction of the first receive-beam708.

It should be noted that in certain aspects, the direction of the transmit beam may be based on a direction of two or more of the plurality of receive-beams that satisfy the threshold condition. For example, the BS110aor UE120amay utilize a broader directional beam to transmit the radar waveform such that the radar waveform extends over the direction of two or more of the plurality of receive-beams (708,710,712). In certain aspects, if each of the plurality of receive-beams does not satisfy the threshold condition, then the BS110aor UE120amay forego transmitting the radar waveform714, and instead, wait until the next RACH slot to make another set of measurements over the plurality of receive-beams (708,710,712), or a different set of receive-beams having a different set of directions.

Thus, based on the calculated RoT, the BS110aor UE120amay determine to transmit a radar waveform714during one or more symbols (e.g., symbols6and7) in the RACH slot704during time T4. In certain aspects, the radar waveform714may be transmitted using a selected directional transmit beam, wherein the direction of the selected transmit beam is based on the direction of one or more of the plurality of receive-beams that have a measured power that satisfies the threshold condition. In this way, the reflection of the radar waveform that is transmitted is not “lost” in the noise, or jammed by the ambient signals in the air interface.

Once the radar waveform714is transmitted, the BS110aor UE120amay restore the transceiver function to an RF functionality that supports TDD carrier communication.

FIG. 8is a flow diagram illustrating example operations800for spatial sensing and detection of uplink interference, in accordance with certain aspects of the present disclosure. In some examples, the operations800may be performed by a BS110aor UE120a, and may start808at each RACH slot of a TDD communication carrier.

At a first step810, the operations800may initialize with a first receive-beam ID. The first receive-beam ID may correspond to a directional receive-beam at the BS110athat has a first direction.

At a second step812, the operations800may detect a RACH slot in the TDD communication. For example, the BS110amay detect a RACH slot based on a schedule or pattern of RACH slots.

At a third step814, the BS110aor UE120amay configure a transceiver for a receive-beam having a particular direction. For example, at the start of the RACH slot, the BS110amay configure the transceiver for a first directional receive-beam. After a power measurement is received using the first directional receive-beam, the BS110aor UE120amay configure the transceiver for a second directional receive-beam.

At a fourth step816, the BS110aor UE120amay measure power received by the directional receive-beam. For example, the BS110aor UE120amay use the directional receive-beam to determine how much power is ambient in the air interface in a particular direction.

At a fifth step818, the BS110aor UE120amay determine whether the receive-beam scan is complete. For example, the BS110aor UE120amay be configured to generate two or more receive-beams during a single RACH slot to measure ambient power in the air interface in two or more particular directions. If the beam scan is not complete, then the operations800proceed to a sixth step820, where the transceiver is configured for the next receive-beam. If the beam scan is complete, meaning that the two or more receive-beams have been generated, and a power measurement of the air interface in directions corresponding to each beam has been measured, the operations800proceed to a seventh step822, where the BS110aor UE120adetermines if a power value corresponding to a power measurement of the two or more receive-beams satisfies a threshold condition. In some examples, if a power measurement satisfies the threshold condition, the operations proceed to an eighth step824, where the BS110aor UE120atransmits a radar waveform in a direction corresponding to a receive-beam having the power measurement that satisfies the threshold condition. Alternatively, if none of the power measurements of each of the receive-beams satisfy the threshold condition, then the BS110aor UE120amay not transmit a radar waveform.

FIG. 9is a flow diagram illustrating example operations900for wireless communication, in accordance with certain aspects of the present disclosure. The operations900may be performed, for example, by a BS (e.g., such as the BS110ain the wireless communication network100) or a UE (e.g., such as the UE120ain the wireless communication network100). Operations900may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor240ofFIG. 2). Further, the transmission and reception of signals by the BS in operations900may be enabled, for example, by one or more antennas (e.g., antennas234ofFIG. 2). In certain aspects, the transmission and/or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., controller/processor240) obtaining and/or outputting signals.

The operations900may begin, at a first step905, by measuring received power at each of a plurality of receive-beams.

The operations900then proceed to a second step910, by determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition.

The operations900then proceed to a third step915, wherein if the measured power received at the one or more of the plurality of receive-beams satisfies the threshold condition, the operations then proceed to a fourth step920and a fifth step925. In the fourth step920, the operations900include selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition. In the fifth step925, the operations900include transmitting a radar waveform over the directional transmit beam.

In certain aspects, selecting the directional transmit beam further comprises determining which of the one or more of the plurality of receive-beams, having measured power that satisfies the threshold condition, is associated with the lowest measured power relative to the other of the one or more of the plurality of receive-beams, wherein the selected directional transmit beam has the same direction as the receive-beam having the lowest measured power relative to the other of the one or more of the plurality of receive-beams.

In certain aspects, each of the plurality of receive-beams is characterized by an azimuth offset relative to the other receive-beams.

In certain aspects, the operations900further comprise measuring the received power at each of the plurality of receive-beams during a single slot, wherein each of the plurality of receive-beams is measured contiguously and for a duration of at least two symbols.

In certain aspects, the single slot is a random access channel (RACH) slot in a time division duplex (TDD) carrier.

In certain aspects, the operations900further comprise, if the measured power received at the one or more of the plurality of receive-beams does not satisfy the threshold condition, measuring received power at each of the plurality of receive-beams during a next RACH slot.

In certain aspects, the single slot comprises a plurality of symbols. In certain aspects, the plurality of receive-beams comprise at least a first receive-beam and a second receive-beam, wherein the first receive-beam has a duration of a first two symbols of the plurality of symbols, and wherein the second receive-beam has a duration of a second two symbols of the plurality of symbols. In certain aspects, the directional transmit beam has a duration of a third two symbols of the plurality of symbols.

In certain aspects, measuring received power at each of the plurality of receive-beams comprises measuring a power-to-interference ratio at each of the plurality of receive-beams.

FIG. 10illustrates a communications device1000that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated inFIGS. 8 and 9. The communications device1000includes a processing system1002coupled to a transceiver1008. The transceiver1008is configured to transmit and receive signals for the communications device1000via an antenna1010, such as the various signals as described herein. The processing system1002may be configured to perform processing functions for the communications device1000, including processing signals received and/or to be transmitted by the communications device1000.

The processing system1002includes a processor1004coupled to a computer-readable medium/memory1012via a bus1006. In certain aspects, the computer-readable medium/memory1012is configured to store instructions (e.g., computer-executable code) that when executed by the processor1004, cause the processor1004to perform the operations illustrated inFIGS. 8 and 9, or other operations for performing the various techniques discussed herein for spatial sensing and avoiding interference for transmitting a radar waveform. In certain aspects, computer-readable medium/memory1012stores code1032for measuring received power at each of a plurality of receive-beams; code1034for determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition; code1036for selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition; and code1038for transmitting a radar waveform over the directional transmit beam. In certain aspects, the processor1020has circuitry configured to implement the code stored in the computer-readable medium/memory1012. The processor1004includes circuitry1020for measuring received power at each of a plurality of receive-beams; circuitry1022for determining whether the measured power received at one or more of the plurality of receive-beams satisfies a threshold condition; circuitry1024for selecting a directional transmit beam based on a direction of one of the one or more of the plurality of receive-beams that satisfy the threshold condition; and circuitry1026for transmitting a radar waveform over the directional transmit beam.

Additional Considerations

The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, . . . slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. In some examples, 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. In some examples, 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.