Patent Description:
These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform-spread-OFDM (DFT-S-OFDM).

In some systems, different operators (e.g., different Mobile Network Operators (MNOs)) may have base stations and UEs that are interspersed, such that base stations of one operator may be adjacent to one or more base stations of another operator. Each operator, in some deployments, may use operating frequencies that are different such that concurrent transmissions of different operators may not cause significant interference with other operators. However, in some frequency bands and deployments, operators may have overlapping coverage areas in which transmissions of a base station or a UE of a first operator may interfere with transmissions of a second operator. In such cases, techniques for mitigating such interference may be desirable to enhance coexistence of the different operators while providing reliable communications for each operator.

<NPL> discusses requirements for an operator to employ Active Antenna Systems (AAS) or any interference mitigation technique depending on the operator's choice to follow a baseline TDD DL/UL configuration.

<CIT> discloses a method for wireless communications performed by a base station, comprising: determining, based on a location of another base station and information regarding the other base station, that the other base station is likely to experience interference while receiving an uplink transmission due to a downlink transmission by the base station; and forming a null in a beam of the downlink transmission in a direction matching the location of the other base station.

<CIT> discloses an operating method of a base station for determining whether to use a dynamic TDD configuration based on the amount of data to be transmitted by a base station to a terminal.

The described techniques relate to improved methods, systems, devices, and apparatuses that support asymmetric time division duplexing (TDD) coexistence techniques. Various described techniques provide for enhanced coexistence of different operators using TDD communications in a set of frequency bands in which transmissions of a first frequency band may cause interference in a second frequency band. In some cases, a baseline TDD configuration may be established for the set of frequency bands. The baseline TDD configuration may provide that uplink (UL) transmissions and downlink (DL) transmissions within the set of frequency bands are aligned and result in relatively little or no interference among different operators. In some cases, an operator may determine that a TDD configuration that is different from the baseline TDD configuration may be beneficial (e.g., a TDD configuration that provides more DL slots when DL-heavy data traffic is present for served UEs). In such cases, the operator may select an interference mitigation procedure (e.g., using beamformed transmissions, power reductions, other interference mitigation techniques, or combinations thereof) and communicate with one or more UEs using the interference mitigation procedure and TDD configuration that is different than the baseline TDD configuration.

In some cases, the baseline TDD configuration includes a first set of DL slots configured for DL transmissions and a second set of UL slots configured for UL transmissions, and the interference mitigation procedure is only selected when the identified TDD configuration has one or more DL slots that overlap with the second set of UL slots of the baseline TDD configuration. In cases where an operator uses the baseline TDD configuration or a different configuration in which DL slots are non-overlapping with the second set of UL slots is used for communications, the base stations and UEs may communicate without using the interference mitigation procedure.

As defined by claim <NUM>, the invention provides a method for wireless communication, the method comprising: establishing, at a first base station, at least one wireless connection with at least one user equipment, UE, using time division duplexing, TDD, in a first frequency band of a set of frequency bands, wherein the set of frequency bands has an associated baseline TDD configuration; identifying, at the first base station based at least in part on an amount of data for communication between the first base station and the at least one UE, a first TDD configuration that is different than the baseline TDD configuration for communications between the first base station and the at least one UE; selecting, at the first base station, an interference mitigation procedure based at least in part on the identified first TDD configuration; communicating between the first base station and the at least one UE using the first TDD configuration and the interference mitigation procedure; selecting, after the communicating using the first TDD configuration, the baseline TDD configuration for further communications with the at least one UE; discontinuing the interference mitigation procedure based at least in part on the selecting the baseline TDD configuration; and communicating with the at least one UE using the baseline TDD configuration.

Preferred embodiments of the method of claim <NUM> are defined by claims <NUM> to <NUM>.

As defined by claim <NUM>, the invention provides an apparatus for wireless communication, the apparatus comprising: means for establishing, at a first base station, at least one wireless connection with at least one user equipment, UE, using time division duplexing, TDD, in a first frequency band of a set of frequency bands, wherein the set of frequency bands has an associated baseline TDD configuration; means for identifying, at the first base station based at least in part on an amount of data for communication between the first base station and the at least one UE, a first TDD configuration that is different than the baseline TDD configuration for communications between the first base station and the at least one UE; means for selecting, at the first base station, an interference mitigation procedure based at least in part on the identified first TDD configuration; means for communicating between the first base station and the at least one UE using the first TDD configuration and the interference mitigation procedure; means for selecting, after the communicating using the first TDD configuration, the baseline TDD configuration for further communications with the at least one UE; means for discontinuing the interference mitigation procedure based at least in part on the selecting the baseline TDD configuration; and means for communicating with the at least one UE using the baseline TDD configuration.

A preferred embodiment of the apparatus of claim <NUM> is defined by claim <NUM>.

As defined by claim <NUM>, the invention provides a non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions which, when executed by a processor, cause the processor to: establish, at a first base station, at least one wireless connection with at least one user equipment, UE, using time division duplexing, TDD, in a first frequency band of a set of frequency bands, wherein the set of frequency bands has an associated baseline TDD configuration; identify, at the first base station based at least in part on an amount of data for communication between the first base station and the at least one UE, a first TDD configuration that is different than the baseline TDD configuration for communications between the first base station and the at least one UE; select, at the first base station, an interference mitigation procedure based at least in part on the identified first TDD configuration; communicate between the first base station and the at least one UE using the first TDD configuration and the interference mitigation procedure; select, after the communicating using the first TDD configuration, the baseline TDD configuration for further communications with the at least one UE; discontinue the interference mitigation procedure based at least in part on the selecting the baseline TDD configuration; and communicate with the at least one UE using the baseline TDD configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the baseline TDD configuration includes a first set of DL slots configured for DL transmissions and a second set of uplink (UL) slots configured for UL transmissions, and where the interference mitigation procedure may be selected when the identified TDD configuration may have one or more DL slots that overlap with the second set of UL slots of the baseline TDD configuration. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the interference mitigation procedure may be not selected when the identified TDD configuration may have one or more UL slots that overlap with the first set of DL slots of the baseline TDD configuration, and the identified TDD configuration may have one or more DL slots that may be non-overlapping with the second set of slots of the baseline TDD configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of DL slots includes a first subset of DL slots that may be configurable only as DL slots and a second subset of slots that may be flexible slots which may be reconfigured to UL slots based on the selected TDD configuration, and where the second set of UL slots includes a third subset of UL slots that may be configurable only as UL slots and a fourth subset of slots that may be flexible slots which may be reconfigured to DL slots based on the selected TDD configuration. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for scheduling higher priority DL transmissions in the first subset of DL slots, lower priority DL transmissions in the second subset of slots, higher priority UL transmissions in the third subset of UL slots, and lower priority UL transmissions in the fourth subset of slots. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the higher priority DL transmissions include DL synchronization signals, DL broadcast transmissions, or combinations thereof, and the higher priority UL transmissions include, UL control signals, UL random access channel transmissions, or combinations thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first base station may be associated with a first operator of a first wireless communications network and one or more adjacent base stations to the first base station may be associated with a second operator of a second wireless communications network, and where the second operator uses a TDD configuration that may be different than the first TDD configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the interference mitigation procedure provides that, for transmissions of the first operator during TDD slots of the first TDD configuration that may have a different duplex direction than corresponding TDD slots of the baseline TDD configuration, an interference level at the one or more adjacent base stations or one or more UEs associated with the second operator may be below a threshold value.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the interference mitigation procedure includes one or more of active antenna system (AAS) beamforming of downlink transmission beams, reducing transmit power or power spectral density of downlink transmissions, pulse shaping of downlink transmissions, predistortion filtering, or any combinations thereof. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the AAS beamforming includes FD-MIMO beamforming. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the identifying the first TDD configuration may be performed dynamically or semi-statically.

Various aspects of the present disclosure provide techniques for enhanced coexistence of different operators using time division duplexing (TDD) communications. In some cases, the different operators may use frequency bands in a set of frequency bands, and transmissions of a first frequency band may cause interference in a second frequency band. In some cases, a baseline TDD configuration may be established for the set of frequency bands. The baseline TDD configuration may provide that uplink (UL) transmissions and downlink (DL) transmissions within the set of frequency bands are aligned and result in relatively little or no interference among different operators.

In some cases, a first operator using a first frequency band may identify that a first TDD configuration that is different from the baseline TDD configuration may be beneficial for communications with one or more UEs. For example, the one or more UEs may have services or data traffic that use relatively heavy DL or UL transmissions, and the first TDD configuration may have more DL or UL slots than the baseline TDD configuration, and may thus provide more efficient communications. The first operator may also, in some cases, select an interference mitigation procedure based on the identification of the first TDD configuration. Such an interference mitigation procedure (e.g., using beamformed transmissions, power reductions, other interference mitigation techniques, or combinations thereof) may reduce potential interference with base stations or UEs of a second operator that may have one or more base stations adjacent to base stations of the first operator. The first operator may communicate with one or more UEs using the first TDD configuration and the interference mitigation procedure.

In some cases, the baseline TDD configuration includes a first set of DL slots configured for DL transmissions and a second set of UL slots configured for UL transmissions, and the interference mitigation procedure is only selected when the identified TDD configuration has one or more DL slots that overlap with the second set of UL slots of the baseline TDD configuration. In cases where an operator uses the baseline TDD configuration or a different configuration in which DL slots are non-overlapping with the second set of UL slots, the base stations and UEs may communicate without using the interference mitigation procedure.

In some cases, the baseline TDD configuration may include a number of fixed DL slots, a number of fixed UL slots, and a number of flexible slots. In such cases, the fixed DL slots and fixed UL slots may always be used for DL and UL transmissions, respectively, and the potential for interference in such slots may be relatively low. The flexible slots may, in some cases, be changed from DL slots to UL slots, or vice versa, which may result in increased potential for interference for such changed slots, which may be mitigated by the selected interference mitigation procedure. In some cases, more sensitive transmissions (e.g., DL synchronization signals, DL broadcast transmissions, UL control signals, UL random access channel transmissions, etc.) may be transmitted in the fixed direction slots, and less sensitive transmission (e.g., DL shared channel transmissions, UL shared channel transmissions) may be transmitted in the flexible slots.

Such techniques may allow operators enhanced flexibility for communications in their wireless communications networks. Further, in cases where an operator may not have capability for performing interference mitigation (e.g., certain LTE or <NUM> networks may not support beamforming), the operator may use the baseline TDD configuration or TDD configurations in which UL slots of the baseline TDD configuration are not used for DL transmissions, and may thus avoid having to perform interference mitigation. Other operators (e.g., operators of <NUM> of NR networks that use the set of frequency bands) may elect to perform interference mitigation and have increased flexibility to select various different TDD configurations that may provide more efficient communications.

Aspects of the disclosure are initially described in the context of a wireless communications system. Various examples of TDD configurations are then discussed. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to asymmetric TDD coexistence techniques.

<FIG> illustrates an example of a wireless communications system <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. The wireless communications system <NUM> includes base stations <NUM>, UEs <NUM>, and a core network <NUM>. In some examples, the wireless communications system <NUM> may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system <NUM> may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices. In some cases, wireless communications system <NUM> may use TDD communications in which a baseline TDD configuration may be established and a different TDD configuration may be selected for communications between UEs <NUM> and base stations <NUM>.

Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD), TDD (TDD), or a combination of both.

When referring to TDD slots herein, reference is made to a unit of scheduling in which uplink or downlink transmissions may be transmitted, which in some cases may be a subframe, slot, mini-slot, combinations thereof, or any unit of time associated with TDD uplink or downlink transmissions that is used to define a TDD configuration.

Devices of the wireless communications system <NUM> (e.g., base stations <NUM> or UEs <NUM>) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system <NUM> may include base stations <NUM> and/or UEs <NUM> that can support simultaneous communications via carriers associated with more than one different carrier bandwidth.

As indicated above, in some cases wireless communications system <NUM> may be operated by a first operator and may use TDD for communications between UEs <NUM> and base stations <NUM>. In some cases, a baseline TDD configuration may be established for a set of frequency bands, and the baseline TDD configuration may provide that UL transmissions and DL transmissions within the set of frequency bands are aligned and result in relatively little or no interference among nodes of wireless communications system <NUM> and wireless nodes of a different operators that may be adjacent to one or more UEs <NUM> or base stations <NUM>. In some cases, the first operator may identify that a first TDD configuration, that is different from the baseline TDD configuration, may be beneficial for communications with one or more UEs <NUM>. The first operator may also, in some cases, select an interference mitigation procedure based on the identification of the first TDD configuration. Such an interference mitigation procedure (e.g., using beamformed transmissions, power reductions, other interference mitigation techniques, or combinations thereof) may reduce potential interference with nodes of the one or more different operators. The first operator may communicate with one or more UEs <NUM> using the first TDD configuration and the interference mitigation procedure.

<FIG> illustrates an example of a wireless communications system <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. In some examples, wireless communications system <NUM> may implement aspects of wireless communications system <NUM>. Wireless communications system <NUM> may include a first base station <NUM>-a, a first UE <NUM>-a, and a second UE <NUM>-b, that are each associated with a first operator (operator A) <NUM>. Wireless communications system <NUM> may also include a second base station <NUM>-b, a third UE <NUM>-c, and a fourth UE <NUM>-d, that are each associated with a second operator (operator B) <NUM>. The base stations <NUM> and UEs may be examples of the corresponding devices described with reference to <FIG>. In this example, the first operator <NUM> and the second operator <NUM> may each operate using TDD communications in a set of frequency bands that may have a baseline TDD configuration.

As indicated above, various aspects of the present disclosure provide techniques for coexistence of multiple carriers that may use different, or asymmetric, TDD configurations. In some examples, the first base station <NUM>-a may communicate with the first UE <NUM>-a via downlink transmissions <NUM>-a and uplink transmissions <NUM>-b, and the first base station <NUM>-a may communicate with the second UE <NUM>-b via downlink transmissions <NUM>-a and uplink transmissions <NUM>-b. In some cases, the first base station <NUM>-a may use beamformed transmissions <NUM> for communications with one or more UEs <NUM>. Similarly, the second base station <NUM>-b may communicate with the third UE <NUM>-c via downlink transmissions <NUM>-a and uplink transmissions <NUM>-b, and the second base station <NUM>-b may communicate with the fourth UE <NUM>-d via downlink transmissions <NUM>-a and uplink transmissions <NUM>-b. While only one base station <NUM> and two UEs <NUM> are illustrated for each of the first operator <NUM> and the second operator <NUM>, each operator may have numerous base stations <NUM> and numerous UEs <NUM>, which may be adjacent to one another.

In some cases, the first operator <NUM> and the second operator <NUM> may operate using frequency bands of a set of frequency bands, in which transmissions of one frequency band may cause interference with transmissions of another frequency band. For example, if downlink transmission <NUM>-a is transmitted concurrently with uplink transmission <NUM>-b, interference may result in degradation of each of the transmitted signals. Further, in some cases downlink transmission <NUM>-a may be transmitted at a significantly higher power than uplink transmission <NUM>-b, which may result in significant interference with uplink transmission <NUM>-b. In some cases, the interference may be significant enough that the uplink transmission <NUM>-b is not received at the second base station <NUM>-b. In order to provide coexistence of the first operator <NUM> and the second operator <NUM>, in some cases, synchronized or semi-synchronized operation between the first operator <NUM> and the second operator <NUM> may be utilized to provide reduced interference between uplink transmissions and downlink transmissions. Synchronized operation may be provided when a TDD configuration is mandated for both the first operator <NUM> and the second operator <NUM>. Semi-synchronized operation may be provided when a subset of time slots have synchronized fixed transmission directions (e.g., a first subset of slots are UL slots and a second subset of slots are DL slots), and other time slots may have different flexible transmission directions.

In some aspects of the present disclosure, coexistence between the first operator <NUM> and the second operator <NUM> may be achieved through the establishment of a baseline TDD configuration for the set of frequency bands. The baseline TDD configuration may provide that UL transmissions and DL transmissions within the set of frequency bands are aligned and result in relatively little or no interference among different operators. In some cases, the first operator <NUM> using the first frequency band may identify that a first TDD configuration that is different from the baseline TDD configuration may be beneficial for communications with the first UE <NUM>-a and the second UE <NUM>-b. For example, the first UE <NUM>-a and second UE <NUM>-b may be receiving relatively large amounts of DL data and transmitting relatively little UL data, and the first base station <NUM>-a may determine that a TDD configuration that has more DL slots than the baseline TDD configuration would be preferable for such communications. The first operator <NUM> in such cases, may identify the first TDD configuration and may also, in some cases, select an interference mitigation procedure based on the identification of the first TDD configuration. Such an interference mitigation procedure may reduce potential interference with at the second base station <NUM>-b or the third UE <NUM>-c, for example. In some cases, the first operator <NUM> may only select an interference mitigation procedure when a DL slot of the baseline TDD configuration is reconfigured to be an uplink slot. Examples of semi-synchronous slot allocations, a baseline TDD configuration, and different TDD configurations, are discussed in more detail with respect to <FIG>.

<FIG> illustrates an example of a flexible TDD configuration <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. In some examples, flexible TDD configuration <NUM> may implement aspects of wireless communications system <NUM> or <NUM>. In this example, a semi-synchronous TDD slot allocation may include a first set of fixed DL slots <NUM> (e.g., slots <NUM>-a, <NUM>-b, and <NUM>-c), a second set of flexible slots <NUM> (e.g., slots <NUM>-a, <NUM>-b, and <NUM>-c), and a third set of UL slots <NUM> (e.g., slots <NUM>-a, and <NUM>-b). In such cases, the first set of fixed DL slots <NUM> may be configurable for only downlink transmissions, and the third set of fixed UL slots <NUM> may be configurable for only uplink transmissions. The second set of flexible slots <NUM> may be configured for either UL or DL transmissions. It is noted that the number of slots illustrated in <FIG>, as well as illustrated in <FIG> and <FIG>, are provided for purposes of illustration and discussion only, and numerous different numbers and configurations of slots may be present in a TDD configuration.

Such a semi-synchronous TDD slot allocation may allow an operator flexibility to select a number of DL or UL slots based on current or expected traffic conditions. As discussed above, however, in some cases when adjacent base stations or UEs of different operators have different TDD transmission directions for a slot, interference may result for one or both operators. For example, operators may choose to use semi-statically configured DL/UL partitioning but use different DL/UL patterns, or one or more operators may choose to use dynamic DL/UL partitioning. If unsynchronized operation were to be used, none of the slots would have a certain fixed transmission direction, and any available DL/UL pattern could be selected. In cases such as illustrated in <FIG>, when semi-synchronized TDD slot allocations are used, the DL/UL pattern within the second set of flexible slots <NUM> may be semi-statically or dynamically modified, while the first set of DL slots <NUM> and the third set of UL slots <NUM> have a fixed transmission direction. Thus, the first set of DL slots <NUM> and the third set of UL slots <NUM> may be expected to experience less interference than the second set of flexible slots <NUM>. In some cases, base stations of one or more of the operators may schedule higher priority or more sensitive information, such as DL synchronization signals, DL broadcast, UL control signals, UL PRACH resources, etc., in the first set of DL slots <NUM> and the third set of UL slots. Other lower priority or less sensitive information may be transmitted in the remaining flexible slots <NUM>, which in some cases may include all other signals, including unicast data. Accordingly, such semi- synchronous TDD slot allocation may provide flexibility in scheduling and TDD configuration selection, while also providing reduced interference between different operators having adjacent base stations or UEs.

As indicated above, in some cases an operator may use one or more interference mitigation techniques in the event that one or more of the flexible slots <NUM> may cause interference with a node of another operator. Further, as discussed above, in some cases an operator may not desire to implement interference mitigation techniques, or may not have capability to implement interference mitigation techniques. In such cases, a single fixed TDD configuration may be mandated, which may eliminate the need for additional interference mitigation techniques at an operator, but which reduces flexibility to modify TDD configurations based on traffic characteristics. In some aspects of the current disclosure, a baseline TDD configuration may be established, and operators using the baseline configuration may not need to perform interference mitigation. In cases where an operator wants to use a different TDD configuration than the baseline TDD configuration, the operator may select a different TDD configuration and in some cases may perform interference mitigation to avoid generating interference at nodes of other operators. Thus, operators that are not able to perform interference mitigation may use the baseline TDD configuration, and operators that desire more flexibility may elect to use a different TDD configuration. In some examples, some or all of the TDD slots of the baseline TDD configuration may be changed by an operator. In other examples, the baseline TDD configuration may be a semi-synchronous TDD configuration in which some slots have a fixed duplex direction.

<FIG> illustrates an example of a baseline TDD configuration and a different TDD configuration <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. In some examples, baseline TDD configuration and a different TDD configuration <NUM> may implement aspects of wireless communications system <NUM> or <NUM>. In this example, a baseline TDD configuration <NUM> may employ a semi-synchronous TDD configuration, and have a first set of DL slots <NUM>, a second set of flexible slots <NUM>, and a third set of uplink slots <NUM>. In this example, the baseline TDD configuration <NUM> may include downlink slots <NUM>-a through <NUM>-c, as well as slots <NUM>-a and <NUM>-b (which may together form a first set of DL slots configured for DL transmissions of the baseline TDD configuration <NUM>). The baseline TDD configuration <NUM> may also include uplink slots that include slot <NUM> of the flexible slots <NUM>, and fixed uplink slots <NUM>-a and <NUM>-b (which may together form a second set of UL slots configured for UL transmissions of the baseline TDD configuration <NUM>).

In some cases, as indicated above, an operator may desire to change a TDD configuration for communications between UEs and base stations of the operator. In some cases, a base station of the operator may identify a TDD configuration <NUM> that is different than the baseline TDD configuration <NUM>. In this example, additional DL slots may be desired, and the uplink slot <NUM> may be changed to a downlink slot <NUM> in the identified TDD configuration, which may also include downlink slots <NUM>-a through <NUM>-e, and uplink slots <NUM>-a and <NUM>-b.

In some cases, additional interference that results from the downlink slot <NUM> may be mitigated through one or more interference mitigation procedures that may be performed by base stations or UEs of the operator using the identified TDD configuration <NUM>. In some cases, interference mitigation may be applied to all of the downlink slots <NUM> of the identified TDD configuration <NUM>, although in some cases interference mitigation may be applied only to the downlink slot <NUM> that deviates from the baseline TDD configuration <NUM>. The interference mitigation procedures may include one or more procedures, such as one or more of active antenna system (AAS) beamforming of downlink transmission beams, reducing transmit power or power spectral density of downlink transmissions, pulse shaping of downlink transmissions, predistortion filtering, or any combinations thereof.

Thus, if an operator chooses to follow the baseline TDD configuration <NUM>, that operator may not need to employ AAS or any interference mitigation technique. Further, in some cases, if the operator chooses not to follow the baseline TDD configuration <NUM> but limits operation so that DL slots of the baseline TDD configuration <NUM> are used for UL but not vice versa, that operator may not need to employ AAS or other interference mitigation techniques. An example of such an identified TDD configuration is illustrated in <FIG>.

In this example, the operator may identify TDD configuration <NUM> for communications, in which the downlink slots <NUM>-a and <NUM>-b of the flexible slots <NUM> are changed to uplink slots <NUM>-a and <NUM>-b. As indicated above, in some cases reconfiguring DL slots of the baseline TDD configuration <NUM> to UL slots may not result in significant interference with other DL transmissions of other operators. For example, an uplink transmission of a UE of a first operator may not significantly interfere with a downlink transmission of a base station of a second operator, as the downlink transmission may be transmitted at a higher power and be more readily received at an associated UE of the second operator. Accordingly, in some cases, interference mitigation may not be performed in cases where DL slots of the baseline TDD configuration <NUM> are reconfigured to be UL slots. Thus, in this example, the identified TDD configuration <NUM> includes downlink slots <NUM>-a through <NUM>-c, and uplink slots <NUM>-a, <NUM>-b, as well as the uplink slots <NUM> and <NUM>-a through <NUM>-b that are in the baseline TDD configuration <NUM>.

Again, in this example, if an operator chooses to follow the baseline TDD configuration <NUM>, that operator may not need to employ AAS or any interference mitigation technique. Further, in some cases, if the operator chooses not to follow the baseline TDD configuration <NUM> but limits operation so that DL slots of the baseline TDD configuration <NUM> are used for UL but not vice versa, that operator may not need to employ AAS or other interference mitigation techniques. However, if the operator chooses not to follow the baseline TDD configuration <NUM> and uses slots that are UL in the baseline TDD configuration <NUM> for DL (e.g., as illustrated in <FIG>), the operator may employ AAS or other interference mitigation technique to help ensure that an adjacent operator following the baseline TDD configuration <NUM> is not subject to excessive interference.

<FIG> shows a block diagram <NUM> of a device <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. The device <NUM> may be an example of aspects of a base station <NUM> as described herein. The device <NUM> may include a receiver <NUM>, a communications manager <NUM>, and a transmitter <NUM>. The device <NUM> may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to asymmetric TDD coexistence techniques, etc.). Information may be passed on to other components of the device <NUM>. The receiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>. The receiver <NUM> may utilize a single antenna or a set of antennas.

The communications manager <NUM> may establish at least one wireless connection with at least one UE using TDD in a first frequency band of a set of frequency bands, where the set of frequency bands has an associated baseline TDD configuration, communicate with the at least one UE using the first TDD configuration and the interference mitigation procedure, identify a first TDD configuration that is different than the baseline TDD configuration for communications with the at least one UE, and select an interference mitigation procedure based on the identified first TDD configuration. The communications manager <NUM> may be an example of aspects of the communications manager <NUM> described herein.

<FIG> shows a block diagram <NUM> of a device <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. The device <NUM> may be an example of aspects of a device <NUM> or a base station <NUM> as described herein. The device <NUM> may include a receiver <NUM>, a communications manager <NUM>, and a transmitter <NUM>. The device <NUM> may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The communications manager <NUM> may be an example of aspects of the communications manager <NUM> as described herein. The communications manager <NUM> may include a connection establishment component <NUM>, a TDD configuration component <NUM>, and an interference mitigation manager <NUM>. The communications manager <NUM> may be an example of aspects of the communications manager <NUM> described herein.

The connection establishment component <NUM> may establish at least one wireless connection with at least one UE using TDD in a first frequency band of a set of frequency bands, where the set of frequency bands has an associated baseline TDD configuration and communicate with the at least one UE using the first TDD configuration and the interference mitigation procedure.

The TDD configuration component <NUM> may identify a first TDD configuration that is different than the baseline TDD configuration for communications with the at least one UE.

The interference mitigation manager <NUM> may select an interference mitigation procedure based on the identified first TDD configuration.

<FIG> shows a block diagram <NUM> of a communications manager <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. The communications manager <NUM> may be an example of aspects of a communications manager <NUM>, a communications manager <NUM>, or a communications manager <NUM> described herein. The communications manager <NUM> may include a connection establishment component <NUM>, a TDD configuration component <NUM>, an interference mitigation manager <NUM>, a scheduling component <NUM>, and a beamforming manager <NUM>. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The connection establishment component <NUM> may establish at least one wireless connection with at least one UE using TDD in a first frequency band of a set of frequency bands, where the set of frequency bands has an associated baseline TDD configuration. In some examples, the connection establishment component <NUM> may communicate with the at least one UE using the first TDD configuration and the interference mitigation procedure. In some examples, the connection establishment component <NUM>, before or after communications using the first TDD configuration, may communicate with the at least one UE using the baseline TDD configuration without using interference mitigation procedures.

The TDD configuration component <NUM> may identify a first TDD configuration that is different than the baseline TDD configuration for communications with the at least one UE. In some examples, the TDD configuration component <NUM> may select, before or after the communicating using the first TDD configuration, the baseline TDD configuration for communications with the at least one UE. In some cases, a first set of DL slots of the baseline TDD configuration may include a first subset of DL slots that are configurable only as DL slots and a second subset of slots that are flexible slots which may be reconfigured to UL slots based on the selected TDD configuration, and a second set of UL slots of the baseline TDD configuration may include a third subset of UL slots that are configurable only as UL slots and a fourth subset of slots that are flexible slots which may be reconfigured to DL slots based on the selected TDD configuration.

The scheduling component <NUM>, in some examples, may schedule higher priority DL transmissions in the first subset of DL slots, lower priority DL transmissions in the second subset of slots, higher priority UL transmissions in the third subset of UL slots, and lower priority UL transmissions in the fourth subset of slots. In some cases, the higher priority DL transmissions include DL synchronization signals, DL broadcast transmissions, or combinations thereof, and the higher priority UL transmissions include, UL control signals, UL random access channel transmissions, or combinations thereof.

In some cases, the first base station is associated with a first operator of a first wireless communications network and one or more adjacent base stations to the first base station are associated with a second operator of a second wireless communications network, and where the second operator uses a TDD configuration that is different than the first TDD configuration. In some cases, the identifying the first TDD configuration is performed dynamically or semi-statically.

The interference mitigation manager <NUM> may select an interference mitigation procedure based on the identified first TDD configuration. In some examples, the interference mitigation manager <NUM> may discontinue the interference mitigation procedure or not select an interference mitigation procedure based on the baseline TDD configuration being selected for communications with the one or more UEs.

In some cases, the baseline TDD configuration includes a first set of DL slots configured for DL transmissions and a second set of uplink (UL) slots configured for UL transmissions, and where the interference mitigation procedure is selected when the identified TDD configuration has one or more DL slots that overlap with the second set of UL slots of the baseline TDD configuration. In some cases, the interference mitigation procedure is not selected when the identified TDD configuration has one or more UL slots that overlap with the first set of DL slots of the baseline TDD configuration, and the identified TDD configuration has one or more DL slots that are non-overlapping with the second set of slots of the baseline TDD configuration.

In some cases, the interference mitigation procedure provides that, for transmissions of the first operator during TDD slots of the first TDD configuration that have a different duplex direction than corresponding TDD slots of the baseline TDD configuration, an interference level at the one or more adjacent base stations or one or more UEs associated with the second operator are below a threshold value. In some cases, the threshold value may be established as a predefined threshold value that provides that the one or more adjacent base station or UEs are able to receive transmissions reliably. In some cases, the threshold value may be a predefined value provided by a government or other entity that regulates the set of frequency bands.

In some cases, the interference mitigation procedure includes one or more of active antenna system (AAS) beamforming of downlink transmission beams, reducing transmit power or power spectral density of downlink transmissions, pulse shaping of downlink transmissions, predistortion filtering, or any combinations thereof.

The beamforming manager <NUM> may manage, in some examples, AAS beamforming in accordance with full dimension MIMO (FD-MIMO) beamforming techniques (e.g., beamforming that includes beamforming in both a vertical dimension and horizontal dimension).

<FIG> shows a diagram of a system <NUM> including a device <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. The device <NUM> may be an example of or include the components of device <NUM>, device <NUM>, or a base station <NUM> as described herein. The device <NUM> may include components for bidirectional voice and data communications including components for transmitting and receiving communications, including a communications manager <NUM>, a network communications manager <NUM>, a transceiver <NUM>, an antenna <NUM>, memory <NUM>, a processor <NUM>, and an inter-station communications manager <NUM>. These components may be in electronic communication via one or more buses (e.g., bus <NUM>).

The communications manager <NUM> may establish, at a first base station, at least one wireless connection with at least one UE using TDD in a first frequency band of a set of frequency bands, where the set of frequency bands has an associated baseline TDD configuration, communicate with the at least one UE using the first TDD configuration and the interference mitigation procedure, identify a first TDD configuration that is different than the baseline TDD configuration for communications with the at least one UE, and select an interference mitigation procedure based on the identified first TDD configuration.

The processor <NUM> may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor <NUM> may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor <NUM>. The processor <NUM> may be configured to execute computer-readable instructions stored in a memory (e.g., the memory <NUM>) to cause the device #{device} to perform various functions (e.g., functions or tasks supporting asymmetric TDD coexistence techniques).

<FIG> shows a flowchart illustrating a method <NUM> that supports asymmetric TDD coexistence techniques in accordance with aspects of the present disclosure. The operations of method <NUM> may be implemented by a base station <NUM> or its components as described herein. For example, the operations of method <NUM> may be performed by a communications manager as described with reference to <FIG>. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At <NUM>, the base station may establish at least one wireless connection with at least one UE using TDD in a first frequency band of a set of frequency bands, where the set of frequency bands has an associated baseline TDD configuration. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a connection establishment component as described with reference to <FIG>. In some cases, the first base station is associated with a first operator of a first wireless communications network and one or more adjacent base stations to the first base station are associated with a second operator of a second wireless communications network, and where the second operator uses a TDD configuration that is different than the first TDD configuration.

At <NUM>, the base station may identify a first TDD configuration that is different than the baseline TDD configuration for communications with the at least one UE. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a TDD configuration component as described with reference to <FIG>. In some cases, the identifying the first TDD configuration is performed dynamically or semi-statically.

At <NUM>, the base station may select an interference mitigation procedure based on the identified first TDD configuration. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by an interference mitigation manager as described with reference to <FIG>. In some cases, the baseline TDD configuration includes a first set of DL slots configured for DL transmissions and a second set of UL slots configured for UL transmissions, and where the interference mitigation procedure is selected only when the identified TDD configuration has one or more DL slots that overlap with the second set of UL slots of the baseline TDD configuration. In some cases, the interference mitigation procedure is not selected when the identified TDD configuration has one or more UL slots that overlap with the first set of DL slots of the baseline TDD configuration, and the identified TDD configuration has one or more DL slots that are non-overlapping with the second set of slots of the baseline TDD configuration. In some cases, the interference mitigation procedure includes one or more of active antenna system (AAS) beamforming of downlink transmission beams, reducing transmit power or power spectral density of downlink transmissions, pulse shaping of downlink transmissions, predistortion filtering, or any combinations thereof.

In some cases, the first set of DL slots includes a first subset of DL slots that are configurable only as DL slots and a second subset of slots that are flexible slots which may be reconfigured to UL slots based on the selected TDD configuration, and where the second set of UL slots includes a third subset of UL slots that are configurable only as UL slots and a fourth subset of slots that are flexible slots which may be reconfigured to DL slots based on the selected TDD configuration. In some cases, the base station may schedule higher priority DL transmissions in the first subset of DL slots, lower priority DL transmissions in the second subset of slots, higher priority UL transmissions in the third subset of UL slots, and lower priority UL transmissions in the fourth subset of slots.

At <NUM>, the base station may communicate with the at least one UE using the first TDD configuration and the interference mitigation procedure. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a connection establishment component as described with reference to <FIG>.

At <NUM>, the base station may establish at least one wireless connection with at least one UE using TDD in a first frequency band of a set of frequency bands, where the set of frequency bands has an associated baseline TDD configuration. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a connection establishment component as described with reference to <FIG>.

At <NUM>, the base station may identify a first TDD configuration that is different than the baseline TDD configuration for communications with the at least one UE. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a TDD configuration component as described with reference to <FIG>.

At <NUM>, the base station may select an interference mitigation procedure based on the identified first TDD configuration. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by an interference mitigation manager as described with reference to <FIG>.

At <NUM>, the base station may select, after the communicating using the first TDD configuration, the baseline TDD configuration for further communications with the at least one UE. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a TDD configuration component as described with reference to <FIG>.

At <NUM>, the base station may discontinue the interference mitigation procedure based on the selecting the baseline TDD configuration. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by an interference mitigation manager as described with reference to <FIG>.

At <NUM>, the base station may communicate with the at least one UE using the baseline TDD configuration. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a connection establishment component as described with reference to <FIG>.

Due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these.

Claim 1:
A method for wireless communication, the method comprising:
establishing (<NUM>), at a first base station, at least one wireless connection with at least one user equipment, UE, using time division duplexing, TDD, in a first frequency band of a set of frequency bands, wherein the set of frequency bands has an associated baseline TDD configuration;
identifying (<NUM>), at the first base station based at least in part on an amount of data for communication between the first base station and the at least one UE, a first TDD configuration that is different than the baseline TDD configuration for communications between the first base station and the at least one UE;
selecting (<NUM>), at the first base station, an interference mitigation procedure based at least in part on the identified first TDD configuration;
communicating (<NUM>) between the first base station and the at least one UE using the first TDD configuration and the interference mitigation procedure;
selecting (<NUM>), after the communicating using the first TDD configuration, the baseline TDD configuration for further communications with the at least one UE;
discontinuing (<NUM>) the interference mitigation procedure based at least in part on the selecting the baseline TDD configuration; and
communicating (<NUM>) with the at least one UE using the baseline TDD configuration.