Patent Description:
3GPP draft R1-<NUM> describes aspects of NR RIM.

In some aspects, a method of wireless communication, performed by a base station, may include detecting interference, in a remote interference management (RIM) scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion. The method may include transmitting, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected.

In some aspects, a base station for wireless communication may include memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to detect interference, in a remote interference management (RIM) scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion. The memory and the one or more processors may be configured to transmit, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to detect interference, in a remote interference management (RIM) scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to transmit, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected.

In some aspects, an apparatus for wireless communication may include means for detecting interference, in a remote interference management (RIM) scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion. The apparatus may include means for transmitting, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, victim base station, aggressor base station, wireless communication device, and processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.

Wireless network <NUM> may include a number of BSs <NUM> (shown as BS <NUM>10a, BS 110b, BS 110c, and BS 110d) and other network entities.

At base station <NUM>, a transmit processor <NUM> may receive data from a data source <NUM> for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (COIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS(s) selected for the UE, and provide data symbols for all UEs.

In some aspects, one or more components ofUE <NUM> may be included in a housing.

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with reference signal transmission in a remote interference management scenario, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG> and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively.

In some aspects, base station <NUM> may include means for detecting interference, in a remote interference management (RIM) scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion, means for transmitting, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected, and/or the like. In some aspects, such means may include one or more components of base station <NUM> described in connection with <FIG>.

<FIG> shows an example frame structure <NUM> for FDD in a telecommunications system (e.g., NR). Each subframe may have a predetermined duration (e.g., <NUM>) and may include a set of slots (e.g., <NUM>m slots per subframe are shown in <FIG>, where m is a numerology used for a transmission, such as <NUM>, <NUM>,<NUM>, <NUM>, <NUM>, and/or the like).

For example, the PSS may be used by UEs to determine symbol timing, and die SSS may be used by UEs to determine a physical cell identifier, associated with the base station, and frame timing.

In some aspects, the SS bursts may have a burst period, whereby the SS blocks of the SS burst are transmitted by the base station according to die burst period.

Other examples are possible and may differ from what was described with regard to <FIG> and <FIG>.

An interlace structure may be used for each of the downlink and uplink for FDD in certain telecommunications systems (e.g., NR). For example, Q interlaces with indices of <NUM> through Q - <NUM> may be defined, where Q may be equal to <NUM>, <NUM>, <NUM>, <NUM>, or some other value. Each interlace may include slots that are spaced apart by Q frames. In particular, interlace q may include slots q, q + Q, q + 2Q, etc., where q ∈ {<NUM>,.

NR resource blocks may span <NUM> sub-carriers with a sub-carrier bandwidth of <NUM> or <NUM> kilohertz (kHz) over a <NUM>. <NUM> millisecond (ms) duration.

MIMO transmissions with preceding may also be supported.

A TRP may include one or more antenna parts.

As indicated above. <FIG> is provided merely as an example.

In most scenarios, a downlink signal of a base station is only observable within and around the edges of coverage areas of cells provided by the base station. In some scenarios, however, the downlink signal of the base station may propagate far beyond the coverage area (e.g., by tens of kilometers, hundreds of kilometers, etc.) as a result of atmospheric ducting; reflections by mountains, the ocean surface, or clouds; and/or the like. In such a case, the downlink signal of the base station may create interference for another base station, which may be termed a remote interference condition or a remote interference management scenario. The base station that transmits the downlink signal may be referred to as an aggressor base station and the base station that receives the downlink signal may be referred to as a victim base station. In some cases, interference may be reciprocal, such that a first base station is an aggressor to a second base station (which is thus a victim), and the second base station is an aggressor to the first base station (which is thus a victim). In some cases, a plurality of base stations may be aggressors and/or victims. For example, communications of a victim base station may be interfered with by transmissions from a plurality of aggressor base stations.

One situation where a remote interference condition may occur is when the aggressor base station and the victim base station have the same time division duplexing (TDD) configuration. This may occur because the aggressor base station and the victim base station are far apart, so normal interference countermeasures (e.g., different TDD configurations, gaps, etc.) do not take into account both the victim base station and the aggressor base station. A downlink signal of the aggressor base station, with the propagation delay between the aggressor base station and the victim base station, may overlap into an uplink portion of the victim base station's frame configuration. This may cause interference between the downlink communications detected by the victim base station and uplink communications to the victim base station.

The victim base station, the aggressor base station, and/or another device (e.g., a UE associated with the victim base station, a network device, an operation/administration/management device, etc.) may perform one or more remote interference management (RIM) operations to mitigate remote interference. In some cases, two or more devices may coordinate to perform RIM operations to mitigate remote interference. For example, the victim base station and die aggressor base station may alter respective communication configurations to reduce a likelihood of overlap between downlink transmissions of the aggressor base station and uplink transmissions of the victim base station. Similarly, the aggressor base station may alter a transmit power, a transmit angle, and/or the like to reduce a likelihood that transmissions of the aggressor base station interfere with communications of the victim base station, and the victim base station may alter a gain value, a receive angle, and/or the like to reduce a likelihood of receiving transmissions of the aggressor base station. Base stations may transmit reference signals to enable measurement of channel conditions, to measure interference, and/or to indicate that an interference condition is detected, which may enable the base stations to determine a RIM operation that may be successful in mitigating remote interference.

In some cases, a victim base station may define a set of reference signals, such that each reference signal is associated with a different frequency domain, time domain, and/or code domain. For example, a victim base station may transmit a reference signal defined for and using a particular sub-band of a plurality of sub-bands. In this case, the aggressor base station may determine the particular sub-band based at least in part on, for example, an index of the reference signal, and may block transmission on the particular sub-band thereby eliminating an interference condition. However, in some cases, as a result of bandwidth overlapping, interference may span across a plurality of sub-bands. As a result, when the victim base station transmits the reference signal using the particular sub-band, the aggressor base station may fail to determine that the remote interference condition affects one or more other sub-bands, and may fail to block transmission on the one or more other sub-bands, thereby resulting in a continuance of the remote interference condition. Further, interference may be aligned to a portion of the particular sub-band, rather than a whole bandwidth of the particular sub-band. In this case, when the aggressor base station blocks transmission on the whole bandwidth of the particular sub-band, a utilization of network resources may be inefficient.

Some aspects, described herein, may provide for reference signal transmission in a remote interference management (RIM) scenario. For example, a victim base station may detect interference in a set of sub-bands (e.g., in a single sub-band, in a portion of a single sub-band, in a plurality of sub-bands, in portions of a plurality of sub-bands, and/or the like), and may transmit a set of reference signals (e.g., a single reference signal, a plurality of reference signals, and/or the like) to indicate the set of sub-bands. In this way, the victim base station may identify the set of sub-bands in which interference is detected, thereby enabling an aggressor base station to block transmission in the set of sub-bands. In this way, the victim base station reduces a likelihood of and/or a length of an interference condition relative to transmitting a single reference signal to identify a single sub-band. Moreover, the victim base station improves a utilization of network resources by enabling an aggressor base station to block a first portion of a sub-band in which interference is detected and to continue transmitting using a second portion of the same sub-band in which interference is not detected.

<FIG> is a diagram illustrating an example <NUM> of reference signal transmission in a remote interference management scenario, in accordance with various aspects of the present disclosure. As shown in <FIG>, example <NUM> includes an aggressor BS <NUM> and a victim BS <NUM>.

As further shown in <FIG>, and by reference number <NUM>, victim BS <NUM> may detect one or more interference causing transmissions from aggressor BS <NUM>. For example, aggressor BS <NUM> may transmit one or more transmissions that may interfere with transmissions to and/or by victim BS <NUM> in a remote interference management (RIM) scenario. In some aspects, victim BS <NUM> may detect remote interference associated with one or more sub-bands of a plurality of sub-bands of a bandwidth. For example, in a remote interference condition shown by reference number <NUM>, victim BS <NUM> may be associated with a <NUM> megahertz (MHz) bandwidth divided into a set of <NUM> sub-bands of <NUM> each corresponding to a set of <NUM> reference signals shown as RS1, RS2, RS3, RS4, and RS5. In this case, victim BS <NUM> may detect no interference in a first sub-band (corresponding to RS1), and may detect the interference in a portion of a second sub-band (corresponding to RS2), in all of a third sub-band (corresponding to RS3) and all of a fourth sub-band (corresponding to RS4), and in a portion of a fifth sub-band (corresponding to RSS). In other examples of remote interference conditions, victim BS <NUM> may detect interference in all or in a portion of one or more sub-bands (e.g., in all of one or more sub-bands, in a portion of one or more sub-bands, in all of one or more sub-bands and in a portion of one or more other sub-bands, and/or the like). Although some aspects, described herein, are described in terms of a particular quantity and/or arrangement of reference signals and/or sub-bands, other quantities and/or arrangements may be possible.

As further shown in <FIG>, and by reference number <NUM>, victim BS <NUM> may transmit one or more reference signals to aggressor BS <NUM> to trigger a RIM operation (e.g., by aggressor BS <NUM>, by victim BS <NUM>, and/or the like). For example, with regard to the interference condition shown by reference number <NUM>, victim BS <NUM> may transmit a set of <NUM> reference signals (e.g., RS2, RS3, RS4, and RS5) at a single time in a single reference signal transmission cycle to indicate the interference occurring in the second sub-band, the third sub-band, the fourth sub-band, and the fifth sub-band. In this case, victim BS <NUM> may transmit the reference signals to map to all interfered sub-bands. In this way, victim BS <NUM> reduces interference relative to transmitting a single reference signal to identify a single sub-band in which interference is occurring. Additionally, or alternatively, victim BS <NUM> may transmit RS2, RS3, RS4, and RS5, in a single reference signal cycle at <NUM> different times (e.g., using time hopping), such that a single reference signal is transmitted at a time. In this case, victim BS <NUM> may transmit the reference signals to map to partial interfered sub-bands, thereby improving a utilization of network resources.

In some aspects, victim BS <NUM> may transmit a single reference signal. For example, in a RIM scenario with remote interference detected in the second sub-band and the third sub-band, BS <NUM> may transmit a single reference signal to indicate both the second sub-band and the third sub-band, thereby reducing a utilization of network resources relative to transmitting a plurality of reference signals while enabling blocking of transmissions at a plurality of sub-bands. In some aspects, victim BS <NUM> may configure a parameter of a reference signal to indicate a plurality of sub-bands. For example, victim BS <NUM> may transmit a reference signal (e.g., RS2) with a particular frequency index to identify the second sub-band, a particular sequence index or time pattern to identify the third sub-band, and/or the like. In this case, aggressor BS <NUM> may determine the parameters of the reference signal to determine that the reference signal is to indicate interference in the second sub-band and the third sub-band.

In some aspects, victim BS <NUM> may transmit a reference signal to indicate the RIM scenario, and may trigger subsequent communications to identify one or more sub-bands. For example, victim BS <NUM> may transmit a reference signal that includes identification information (e.g., a cell identifier) to enable aggressor BS <NUM> and victim BS <NUM> to establish a backhaul connection to communicate regarding which sub-bands remote interference is detected. In some aspects, victim BS <NUM> may transmit a narrowband reference signal. For example, victim BS <NUM> may transmit a reference signal that is associated with a reduced frequency domain, a shortened sequence, an extended time pattern, and/or the like relative to other reference signals to indicate interference in one or more sub-bands. In some aspects, victim BS <NUM> may transmit repetitions of a reference signal. In some aspects, victim BS <NUM> may transmit an assistance reference signal. For example, victim BS <NUM> may transmit RS3 to indicate the third sub-band is interfered with based at least in part on a frequency index and that the second sub-band is interfered with based at least in part on a sequence index, and may cause aggressor BS <NUM> to establish a backhaul connection, with which victim BS <NUM> may indicate interference in the fourth sub-band and the fifth sub-band.

Although some aspects, described herein, are described in terms of a victim BS <NUM> transmitting a reference signal to an aggressor BS <NUM>, an aggressor BS <NUM> may transmit a reference signal to a victim BS <NUM>, and may configure the reference signal to identify a set of sub-bands in which interference is detected.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a base station (e.g., BS <NUM>) performs reference signal transmission in a remote interference management scenario.

As shown in <FIG>, in some aspects, process <NUM> may include detecting interference, in a remote interference management (RIM) scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion (block <NUM>). For example, the base station (e.g., using antenna <NUM>, DFMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, and/or the like) may detect interference, in a RIM scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion, as described in more detail above.

As shown in <FIG>, in some aspects, process <NUM> may include transmitting, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected (block <NUM>). For example, the base station (e.g., controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like) may transmit, to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected, as described in more detail above.

In some aspects, the set of reference signals is a plurality of reference signals. In some aspects, the base station is configured to transmit the set of reference signals using the set of sub-bands at a single time period of a single reference signal transmission cycle. In some aspects, the base station is configured to transmit the set of reference signals using the set of sub-bands at a plurality of time periods of a single reference signal transmission cycle.

In some aspects, the set of reference signals identifies a fully interfered sub-band of the set of sub-bands. In some aspects, the set of reference signals identifies a partially interfered sub-band of the set of sub-bands. In some aspects, the set of sub-bands is at least a portion of two or more sub-bands.

In some aspects, the set of reference signals is a single reference signal. In some aspects, a single reference signal, of the set of reference signals, identifies two or more sub-bands of the set of sub-bands. In some aspects, a frequency index of a reference signal, of the set of reference signals, identifies a sub-band of the set of sub-bands.

In some aspects, a sequence index or a time pattern of a reference signal, of the set of reference signals, identifies a sub-band of the set of sub-bands. In some aspects, the base station is a victim base station and is configured to communicate, using a backhaul connection, with an aggressor base station associated with the interference to identify the set of sub-bands. In some aspects, a reference signal, of the set of reference signals, indicates identification information associated with establishing a backhaul communication with another base station.

In some aspects, a reference signal, of the set of reference signals, is a narrowband reference signal with repetition in a sub-band of the set of sub-bands. In some aspects, a reference signal, of the set of reference signals, is associated with, relative to other reference signals, at least one of: a shortened sequence, or an extended time pattern. In some aspects, a reference signal, of the set of reference signals, is an assistance reference signal.

Claim 1:
A method of wireless communication performed by a base station, comprising:
detecting (<NUM>) interference, in a remote interference management, RIM, scenario, in a set of sub-bands of a plurality of sub-bands of a bandwidth portion; and
transmitting (<NUM>), to identify the set of sub-bands in which interference is detected, a set of reference signals configured to indicate the set of sub-bands in which the interference is detected.