Patent Publication Number: US-2018035435-A1

Title: Mechanisms for interference management of multi-tti sidelink-centric subframes in wireless communication

Description:
PRIORITY CLAIM 
     This application claims priority to and the benefit of provisional patent application No. 62/367,346 filed in the United States Patent and Trademark Office on 27 Jul. 2016, the entire content of which is incorporated herein by reference as if fully set forth below in its entirety and for all applicable purposes. 
    
    
     TECHNICAL FIELD 
     The technology discussed herein relates, generally, to wireless communication systems, and, more particularly, to using sidelink-centric subframes for wireless communication. 
     INTRODUCTION 
     Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communication for multiple users by sharing the available network resources. Within such wireless networks a variety of data services may be provided, including voice, video, online access, and emails. The spectrum allocated to such wireless communication networks can include licensed spectrum and/or unlicensed spectrum. As the demand for mobile broadband access continues to increase, research and development continue to advance wireless communication technologies not only to meet the growing demand for mobile broadband access, but also to advance and enhance the user experience with mobile communications. 
     A user equipment (UE) may have the ability to communicate directly with another UE without relaying such communication through a network node or base station, such as an evolved Node B (eNB) or scheduling entity. However, in some circumstances, UE-to-UE or peer-to-peer communications may potentially interfere with eNB-to-UE communications and/or other UE-to-UE communications. Interference management in such circumstances may enhance communication efficiency and throughput, thereby improving the overall user experience. 
     BRIEF SUMMARY OF SOME EXAMPLES 
     The following presents a simplified summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a simplified form as a prelude to the more detailed description that is presented later. 
     Aspects of the present disclosure provide solutions that can mitigate interference between sidelinks. A user equipment (UE) can directly communicate with another device using a sidelink or sidelink channel without necessarily relying on a scheduling entity (e.g., a base station). The UE may perform various processes to mitigate interference between sidelinks established between different sidelink entities. 
     One aspect of the disclosure provides a method of communication by an apparatus. The apparatus receives, from a scheduling entity, sidelink grant information in a downlink control channel. The apparatus further transmits a direction selection signal (DSS) in a first transmission time interval (TTI) utilizing a first sidelink to a first scheduled entity according to the sidelink grant information. The DSS is configured to indicate a requested duration of time to keep the first sidelink available for a plurality of TTIs including the first TTI. The apparatus further mitigates interference between the first sidelink and a second sidelink established between other scheduled entities different from the first scheduled entity. To mitigate interference, the apparatus may puncture sidelink data of the first sidelink during a first time period of at least one of the TTIs, wherein the first time period overlaps with a first destination receive signal (DRS) of the second sidelink. To mitigate interference, the apparatus may receive, from the first scheduled entity in the first TTI, a retransmission of a second DRS in a second time period that is not interfered by the second sidelink. 
     Another aspect of the disclosure provides an apparatus for wireless communication. The apparatus includes a communication interface configured to communicate with a scheduling entity, a first scheduled entity, and a second scheduled entity. The apparatus further includes a memory stored with executable code and a processor operatively coupled with the communication interface and the memory. The processor is configured by the executable code to receive, from the scheduling entity, sidelink grant information in a downlink control channel. The processor is further configured to transmit a direction selection signal (DSS) in a first transmission time interval (TTI) utilizing a first sidelink to the first scheduled entity according to the sidelink grant information, wherein the DSS is configured to indicate a requested duration of time to keep the first sidelink available for a plurality of TTIs including the first TTI. The apparatus is further configured to mitigate interference between the first sidelink and a second sidelink established between other scheduled entities different from the first scheduled entity. To mitigate interference, the processor may be configured to puncture sidelink data of the first sidelink during a first time period of at least one of the TTIs, wherein the first time period overlaps with a first destination receive signal (DRS) of the second sidelink. To mitigate interference, the processor may be configured to receive, from the first scheduled entity in the first TTI, a retransmission of a second DRS in a second time period that is not interfered by the second sidelink. 
     Another aspect of the disclosure provides an apparatus for wireless communication. The apparatus includes means for receiving, from a scheduling entity, sidelink grant information in a downlink control channel. The apparatus further includes means for transmitting a direction selection signal (DSS) signal in a first transmission time interval (TTI) utilizing a first sidelink to a first scheduled entity according to the sidelink grant information, wherein the DSS is configured to indicate a requested duration of time to keep the first sidelink available for a plurality of TTIs including the first TTI. The apparatus further includes means for mitigating interference between the first sidelink and a second sidelink established between other scheduled entities different from the first scheduled entity. The means for mitigating interference may be configured to puncture sidelink data of the first sidelink during a first time period of at least one of the TTIs, wherein the first time period overlaps with a first destination receive signal (DRS) of the second sidelink. The means for mitigating interference may be configured to receive, from the first scheduled entity in the first TTI, a retransmission of a second DRS in a second time period that is not interfered by the second sidelink. 
     These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an example of an access network according to some aspects of the present disclosure. 
         FIG. 2  is a diagram conceptually illustrating an example of a scheduling entity communicating with one or more scheduled entities according to some aspects of the present disclosure. 
         FIG. 3  is a diagram illustrating an example of a hardware implementation for a scheduling entity according to some aspects of the present disclosure. 
         FIG. 4  is a diagram illustrating an example of a hardware implementation for a scheduled entity according to some aspects of the present disclosure. 
         FIG. 5  is a diagram illustrating an example of a downlink (DL)-centric subframe according to some aspects of the present disclosure. 
         FIG. 6  is a diagram illustrating an example of an uplink (UL)-centric subframe according to some aspects of the present disclosure. 
         FIG. 7  is a diagram illustrating an example of a sidelink-centric subframe according to some aspects of the present disclosure. 
         FIG. 8  is a diagram illustrating an example of sidelink-centric subframes extending across a plurality of transmission time intervals (TTIs) according to some aspects of the present disclosure. 
         FIG. 9  is a diagram illustrating another example of a sidelink-centric subframe according to some aspects of the present disclosure. 
         FIG. 10  is a diagram illustrating another example of sidelink-centric subframes extending across a plurality of TTIs according to some aspects of the present disclosure. 
         FIG. 11  is a diagram illustrating yet another example of sidelink-centric subframes extending across a plurality of TTIs. 
         FIG. 12  is a diagram illustrating an interference scenario between sidelink-centric subframes extending across multiple TTIs. 
         FIG. 13  is a diagram illustrating an example of a destination receive signal (DRS) protection scheme using data puncturing according to some aspects of the present disclosure. 
         FIG. 14  is a diagram illustrating an example of data puncturing process according to some aspects of the present disclosure. 
         FIG. 15  is a diagram illustrating an example of a DRS protection scheme using retransmission according to some aspects of the present disclosure. 
         FIG. 16  is a flowchart illustrating a method of sidelink interference management according to some aspects of the present disclosure. 
         FIG. 17  is a flowchart illustrating another method of sidelink interference management according to some aspects of the present disclosure. 
         FIG. 18  is a flowchart illustrating still another method of sidelink interference management according to some aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts. 
     Aspects of the present disclosure provide solutions that can mitigate interference between sidelinks. A user equipment (UE) can directly communicate with another device using a sidelink or sidelink channel without necessarily relying on a scheduling entity (e.g., a base station). The UE may transmit a direction selection signal (DSS) to another sidelink entity to indicate a requested duration of time to keep a first sidelink available for a plurality of transmission time intervals. The UE may perform various processes to mitigate interference between the first sidelink and a second sidelink established between other sidelink entities. To mitigate interference between sidelinks, for example, the UE may puncture its sidelink data during a time period that overlaps with a destination receive signal (DRS) of another sidelink. In another example, the UE may receive a retransmission of a DRS that may not be received due to sidelink interference. 
     The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now to  FIG. 1 , as an illustrative example without limitation, a schematic illustration of a radio access network  100  is provided. 
     The geographic region covered by the radio access network  100  may be divided into a number of cellular regions (cells) that can be uniquely identified by a user equipment (UE) based on an identification broadcasted over a geographical area from one access point or base station.  FIG. 1  illustrates macrocells  102 ,  104 , and  106 , and a small cell  108 , each of which may include one or more sectors. A sector is a sub-area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging to that sector. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with UEs in a portion of the cell. 
     In general, a base station (BS) serves each cell. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception in one or more cells to or from a UE. A BS may also be referred to by those skilled in the art as a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B (NB), an eNode B (eNB), or some other suitable terminology. 
     In  FIG. 1 , two high-power base stations  110  and  112  are shown in cells  102  and  104 ; and a third high-power base station  114  is shown controlling a remote radio head (RRH)  116  in cell  106 . That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by feeder cables. In the illustrated example, the cells  102 ,  104 , and  106  may be referred to as macrocells, as the high-power base stations  110 ,  112 , and  114  support cells having a large size. Further, a low-power base station  118  is shown in the small cell  108  (e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc.) which may overlap with one or more macrocells. In this example, the cell  108  may be referred to as a small cell, as the low-power base station  118  supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints. It is to be understood that the radio access network  100  may include any number of wireless base stations and cells. Further, a relay node may be deployed to extend the size or coverage area of a given cell. The base stations  110 ,  112 ,  114 ,  118  provide wireless access points to a core network for any number of mobile apparatuses. 
       FIG. 1  further includes a quadcopter or drone  120 , which may be configured to function as a base station. That is, in some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station such as the quadcopter  120 . 
     In general, base stations may include a backhaul interface for communication with a backhaul portion of the network. The backhaul may provide a link between a base station and a core network, and in some examples, the backhaul may provide interconnection between the respective base stations. The core network is a part of a wireless communication system that is generally independent of the radio access technology used in the radio access network. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network. Some base stations may be configured as integrated access and backhaul (IAB) nodes, where the wireless spectrum may be used both for access links (i.e., wireless links with UEs), and for backhaul links. This scheme is sometimes referred to as wireless self-backhauling. By using wireless self-backhauling, rather than requiring each new base station deployment to be outfitted with its own hard-wired backhaul connection, the wireless spectrum utilized for communication between the base station and UE may be leveraged for backhaul communication, enabling fast and easy deployment of highly dense small cell networks. 
     The radio access network  100  is illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus is commonly referred to as user equipment (UE) in standards and specifications promulgated by the 3rd Generation Partnership Project (3GPP), but may also be referred to by those skilled in the art as a mobile station (MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE may be an apparatus that provides a user with access to network services. 
     Within the present document, a “mobile” apparatus need not necessarily have a capability to move, and may be stationary. The term mobile apparatus or mobile device broadly refers to a diverse array of devices and technologies. For example, some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC), a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA), and a broad array of embedded systems, e.g., corresponding to an “Internet of things” (IoT). A mobile apparatus may additionally be an automotive or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer and/or wearable device, such as eyewear, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player), a camera, a game console, etc. A mobile apparatus may additionally be a digital home or smart home device such as a home audio, video, and/or multimedia device, an appliance, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus may additionally be a smart energy device, a security device, a solar panel or solar array, a municipal infrastructure device controlling electric power (e.g., a smart grid), lighting, water, etc.; an industrial automation and enterprise device; a logistics controller; agricultural equipment; military defense equipment, vehicles, aircraft, ships, and weaponry, etc. Still further, a mobile apparatus may provide for connected medicine or telemedicine support, i.e., health care at a distance. Telehealth devices may include telehealth monitoring devices and telehealth administration devices, whose communication may be given preferential treatment or prioritized access over other types of information, e.g., in terms of prioritized access for transport of critical service data, and/or relevant QoS for transport of critical service data. 
     Within the radio access network  100 , the cells may include UEs that may be in communication with one or more sectors of each cell. For example, UEs  122  and  124  may be in communication with base station  110 ; UEs  126  and  128  may be in communication with base station  112 ; UEs  130  and  132  may be in communication with base station  114  by way of RRH  116 ; UE  134  may be in communication with low-power base station  118 ; and UE  136  may be in communication with mobile base station  120 . Here, each base station  110 ,  112 ,  114 ,  118 , and  120  may be configured to provide an access point to a core network (not shown) for all the UEs in the respective cells. 
     In another example, a mobile network node (e.g., quadcopter  120 ) may be configured to function as a UE. For example, the quadcopter  120  may operate within cell  102  by communicating with base station  110 . In some aspects of the disclosure, two or more UE (e.g., UEs  126  and  128 ) may communicate with each other using peer to peer (P2P) or sidelink signals  127  without relaying that communication through a base station (e.g., base station  112 ). 
     Unicast or broadcast transmissions of control information and/or traffic information from a base station (e.g., base station  110 ) to one or more UEs (e.g., UEs  122  and  124 ) may be referred to as downlink (DL) transmission, while transmissions of control information and/or traffic information originating at a UE (e.g., UE  122 ) may be referred to as uplink (UL) transmissions. In addition, the uplink and/or downlink control information and/or traffic information may be transmitted in transmission time intervals (TTIs). As used herein, the term TTI may refer to the inter-arrival time of a given schedulable set of data. In various examples, a TTI may be configured to carry one or more transport blocks, which are generally the basic data unit exchanged between the physical layer (PHY) and medium access control (MAC) layer (sometimes referred to as a MAC PDU, or protocol data unit). In accordance with various aspects of the present disclosure, a subframe may include one or more TTIs. Thus, as further used herein, the term subframe may refer to an encapsulated set of information including one or more TTIs, which is capable of being independently decoded. Multiple subframes may be grouped together to form a single frame or radio frame. Any suitable number of subframes may occupy a frame. In addition, a subframe may have any suitable duration (e.g., 250 ρs, 500 ρs, 1 ms, etc.). 
     The air interface in the radio access network  100  may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, multiple access for uplink (UL) or reverse link transmissions from UEs  122  and  124  to base station  110  may be provided utilizing time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), sparse code multiple access (SCMA), resource spread multiple access (RSMA), or other suitable multiple access schemes. Further, multiplexing downlink (DL) or forward link transmissions from the base station  110  to UEs  122  and  124  may be provided utilizing time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), or other suitable multiplexing schemes. 
     Further, the air interface in the radio access network  100  may utilize one or more duplexing algorithms Duplex refers to a point-to-point communication link where both endpoints can communicate with one another in both directions. Full duplex means both endpoints can simultaneously communicate with one another. Half duplex means only one endpoint can send information to the other at a time. In a wireless link, a full duplex channel generally relies on physical isolation of a transmitter and receiver, and suitable interference cancellation technologies. Full duplex emulation is frequently implemented for wireless links by utilizing frequency division duplex (FDD) or time division duplex (TDD). In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from one another using time division multiplexing. That is, at some time the channel is dedicated for transmissions in one direction, while at other time the channel is dedicated for transmissions in the other direction, where the direction may change very rapidly, e.g., several times per subframe. 
     In the radio access network  100 , the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of a mobility management entity (MME). In various aspects of the disclosure, a radio access network  100  may utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE&#39;s connection from one radio channel to another). In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE  124  (illustrated as a vehicle, although any suitable form of UE may be used) may move from the geographic area corresponding to its serving cell  102  to the geographic area corresponding to a neighbor cell  106 . When the signal strength or quality from the neighbor cell  106  exceeds that of its serving cell  102  for a given amount of time, the UE  124  may transmit a reporting message to its serving base station  110  indicating this condition. In response, the UE  124  may receive a handover command, and the UE may undergo a handover to the cell  106 . 
     In a network configured for UL-based mobility, UL reference signals from each UE may be utilized by the network to select a serving cell for each UE. In some examples, the base stations  110 ,  112 , and  114 / 116  may broadcast unified synchronization signals (e.g., unified Primary Synchronization Signals (PSSs), unified Secondary Synchronization Signals (SSSs) and unified Physical Broadcast Channels (PBCH)). The UEs  122 ,  124 ,  126 ,  128 ,  130 , and  132  may receive the unified synchronization signals, derive the carrier frequency and subframe timing from the synchronization signals, and in response to the derived timing, transmit an uplink pilot or reference signal. The uplink pilot signal transmitted by a UE (e.g., UE  124 ) may be concurrently received by two or more cells (e.g., base stations  110  and  114 / 116 ) within the radio access network  100 . Each of the cells may measure a strength of the pilot signal, and the radio access network (e.g., one or more of the base stations  110  and  114 / 116  and/or a central node within the core network) may determine a serving cell for the UE  124 . As the UE  124  moves through the radio access network  100 , the network may continue to monitor the uplink pilot signal transmitted by the UE  124 . When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds that of the signal strength or quality measured by the serving cell, the network  100  may handover the UE  124  from the serving cell to the neighboring cell, with or without informing the UE  124 . 
     Although the synchronization signal transmitted by the base stations  110 ,  112 , and  114 / 116  may be unified, the synchronization signal may not identify a particular cell, but rather may identify a zone of multiple cells operating on the same frequency and/or with the same timing. The use of zones in 5G networks or other next generation communication networks enables the uplink-based mobility framework and improves the efficiency of both the UE and the network, since the number of mobility messages that need to be exchanged between the UE and the network may be reduced. 
     In various implementations, the air interface in the radio access network  100  may utilize licensed spectrum, unlicensed spectrum, or shared spectrum. Licensed spectrum provides for exclusive use of a portion of the spectrum, generally by virtue of a mobile network operator purchasing a license from a government regulatory body. Unlicensed spectrum provides for shared use of a portion of the spectrum without need for a government-granted license. While compliance with some technical rules is generally still required to access unlicensed spectrum, generally, any operator or device may gain access. Shared spectrum may fall between licensed and unlicensed spectrum, wherein technical rules or limitations may be required to access the spectrum, but the spectrum may still be shared by multiple operators and/or multiple RATs. For example, the holder of a license for a portion of licensed spectrum may provide licensed shared access (LSA) to share that spectrum with other parties, e.g., with suitable licensee-determined conditions to gain access. 
     In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, UEs or scheduled entities utilize resources allocated by the scheduling entity. 
     Base stations are not the only entities that may function as a scheduling entity. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs). In other examples, sidelink signals may be used between UEs without necessarily relying on scheduling or control information from a base station. For example, UE  138  is illustrated communicating with UEs  140  and  142 . In some examples, the UE  138  is functioning as a scheduling entity or a primary sidelink device, and UEs  140  and  142  may function as a scheduled entity or a non-primary (e.g., secondary) sidelink device. In still another example, a UE may function as a scheduling entity in a device-to-device (D2D), peer-to-peer (P2P), or vehicle-to-vehicle (V2V) network, and/or in a mesh network. In a mesh network example, UEs  140  and  142  may optionally communicate directly with one another in addition to communicating with the scheduling entity  138 . 
     Thus, in a wireless communication network with scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, or a mesh configuration, a scheduling entity and one or more scheduled entities may communicate utilizing the scheduled resources. Referring now to  FIG. 2 , a block diagram illustrates a scheduling entity  202  and a plurality of scheduled entities  204  (e.g.,  204   a  and  204   b ). Here, the scheduling entity  202  may correspond to a base station  110 ,  112 ,  114 , and/or  118 . In additional examples, the scheduling entity  202  may correspond to a UE  138 , the quadcopter  120 , or any other suitable node in the radio access network  100 . Similarly, in various examples, the scheduled entity  204  may correspond to the UE  122 ,  124 ,  126 ,  128 ,  130 ,  132 ,  134 ,  136 ,  138 ,  140 , and  142 , or any other suitable node in the radio access network  100 . 
     As illustrated in  FIG. 2 , the scheduling entity  202  may broadcast traffic  206  to one or more scheduled entities  204  (the traffic may be referred to as downlink traffic). In accordance with certain aspects of the present disclosure, the term downlink may refer to a point-to-multipoint transmission originating at the scheduling entity  202 . Broadly, the scheduling entity  202  is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink transmissions and, in some examples, uplink traffic  210  from one or more scheduled entities to the scheduling entity  202 . Another way to describe the system may be to use the term broadcast channel multiplexing. In accordance with aspects of the present disclosure, the term uplink may refer to a point-to-point transmission originating at a scheduled entity  204 . Broadly, the scheduled entity  204  is a node or device that receives scheduling control information, including but not limited to scheduling grants, synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity  202 . 
     The scheduling entity  202  may broadcast control information  208  including one or more control channels, such as a PBCH; a PSS; a SSS; a physical control format indicator channel (PCFICH); a physical hybrid automatic repeat request (HARQ) indicator channel (PHICH); and/or a physical downlink control channel (PDCCH), etc., to one or more scheduled entities  204 . The PHICH carries HARQ feedback transmissions such as an acknowledgment (ACK) or negative acknowledgment (NACK). HARQ is a technique well-known to those of ordinary skill in the art, wherein packet transmissions may be checked at the receiving side for accuracy, and if confirmed, an ACK may be transmitted, whereas if not confirmed, a NACK may be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission, which may implement chase combining, incremental redundancy, etc. 
     Uplink traffic  210  and/or downlink traffic  206  including one or more traffic channels, such as a physical downlink shared channel (PDSCH) or a physical uplink shared channel (PUSCH) (and, in some examples, system information blocks (SIBs)), may additionally be transmitted between the scheduling entity  202  and the scheduled entity  204 . Transmissions of the control and traffic information may be organized by subdividing a carrier, in time, into suitable transmission time intervals (TTIs). For example, a TTI may correspond to an encapsulated set or packet of information capable of being independently decoded. In various examples, TTIs may correspond to frames, subframes, data blocks, time slots, or other suitable groupings of bits for transmission. 
     Furthermore, the scheduled entities  204  may transmit uplink control information  212  including one or more uplink control channels to the scheduling entity  202 . Uplink control information may include a variety of packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink traffic transmissions. In some examples, the control information  212  may include a scheduling request (SR), i.e., request for the scheduling entity  202  to schedule uplink transmissions. Here, in response to the SR transmitted on the control channel  212 , the scheduling entity  202  may transmit downlink control information  208  (e.g., grants) that may schedule the TTI for uplink packet transmissions. 
     Uplink and downlink transmissions may generally utilize a suitable error correcting block code. In a typical block code, an information message or sequence is split up into blocks, and an encoder at the transmitting device then mathematically adds redundancy to the information message. Exploitation of this redundancy in the encoded information message can improve the reliability of the message, enabling correction for any bit errors that may occur due to the noise. Some examples of error correcting codes include Hamming codes, Bose-Chaudhuri-Hocquenghem (BCH) codes, turbo codes, low-density parity check (LDPC) codes, and polar codes. Various implementations of scheduling entities  202  and scheduled entities  204  may include suitable hardware and capabilities (e.g., an encoder and/or decoder) to utilize any one or more of these error correcting codes for wireless communication. 
     In some examples, scheduled entities such as a first scheduled entity  204   a  and a second scheduled entity  204   b  may utilize sidelink signals for direct D2D communication. Sidelink signals may include sidelink traffic  214  and sidelink control  216 . Sidelink control information  216  may include a source transmit signal (STS), a direction selection signal (DSS), a destination receive signal (DRS), and a physical sidelink HARQ indicator channel (PSHICH). The STS/DSS may provide for a scheduled entity  204  to request a duration of time to keep a sidelink channel available for a sidelink signal; and the DRS may provide for the scheduled entity  204  to indicate the availability of the sidelink channel, e.g., for a requested duration of time. An exchange of DSS/STS and DRS signals (e.g., handshake) may enable different scheduled entities performing sidelink communications to negotiate the availability of the sidelink channel prior to communication of the sidelink traffic information  214 . The PSHICH may include HARQ acknowledgment information and/or a HARQ indicator from a destination device, so that the destination may acknowledge data received from a source device. 
     The channels or carriers illustrated in  FIG. 2  are not necessarily all of the channels or carriers that may be utilized between a scheduling entity  202  and scheduled entities  204 , and those of ordinary skill in the art will recognize that other channels or carriers may be utilized in addition to those illustrated, such as other traffic, control, and feedback channels. 
       FIG. 3  is a diagram illustrating an example of a hardware implementation  300  for scheduling entity  202  according to aspects of the present disclosure. Scheduling entity  202  may employ a processing system  314 . Scheduling entity  202  may be implemented with a processing system  314  that includes one or more processors  304 . Examples of processors  304  include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, scheduling entity  202  may be configured to perform any one or more of the functions described herein. That is, the processor  304 , as utilized in scheduling entity  202 , may be used or configured to implement any one or more of the processes described herein, for example, in  FIGS. 12-18 . 
     In this example, the processing system  314  may be implemented with a bus architecture, represented generally by the bus  302 . The bus  302  may include any number of interconnecting buses and bridges depending on the specific application of the processing system  314  and the overall design constraints. The bus  302  communicatively couples together various circuits including one or more processors (represented generally by the processor  304 ), a memory  305 , and computer-readable media (represented generally by the computer-readable medium  306 ). The bus  302  may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits. A bus interface  308  provides an interface between the bus  302  and a transceiver  310 . The transceiver  310  provides a communication interface or a means for communicating with various other apparatuses over a transmission medium. Depending upon the nature of the apparatus, a user interface  312  (e.g., keypad, display, speaker, microphone, joystick) may also be provided. 
     At least one processor  304  is responsible for managing the bus  302  and general processing, including the execution of software stored on the computer-readable medium  306 . The software, when executed by the processor  304 , causes the processing system  314  to perform the various functions described below for any particular apparatus. The computer-readable medium  306  and the memory  305  may also be used for storing data that is manipulated by the processor  304  when executing software. In some aspects of the disclosure, the computer-readable medium  306  may include communication instructions  352 . The communication instructions  352  may include instructions for performing various operations related to wireless communication (e.g., signal reception and/or signal transmission) as described herein. For example, the communication instructions  352  may include code for configuring the processing system  314  and communication interface  310  to communicate and control a plurality of scheduled entities using sidelink communication. In some aspects of the disclosure, the computer-readable medium  306  may include processing instructions  354 . The processing instructions  354  may include instructions for performing various operations related to signal processing (e.g., processing a received signal and/or processing a signal for transmission) as described herein. In one example, the processing instructions  354  include code that may be executed by the processor  304  to control and schedule sidelink communication as described in  FIGS. 7-18 . 
     At least one processor  304  may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium  306 . The computer-readable medium  306  may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD)), a smart card, a flash memory device (e.g., a card, a stick, or a key drive), a random access memory (RAM), a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium  306  may reside in the processing system  314 , external to the processing system  314 , or distributed across multiple entities including the processing system  314 . The computer-readable medium  306  may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system. 
     In some aspects of the disclosure, at least one processor  304  may include a communication circuit  340 . The communication circuit  340  may include one or more hardware components that provide the physical structure that performs various processes related to wireless communication (e.g., signal reception and/or signal transmission) as described herein. For example, the communication circuit  340  may be configured to control and schedule sidelink communication among a plurality of scheduled entities. The communication circuit  340  may transmit or broadcast sidelink grants or control information to the scheduled entities using a downlink control channel (e.g., PDCCH) via the communication interface  310 . In some examples, the sidelink control information may be configured to mitigate interference between sidelinks as described in  FIGS. 12-18 . In some aspects of the disclosure, the processor  304  may also include a processing circuit  342 . The processing circuit  342  may include one or more hardware components that provide the physical structure that performs various processes related to signal processing (e.g., processing a received signal and/or processing a signal for transmission) as described herein. The circuitry included in the processor  304  is provided as non-limiting examples. Other means for carrying out the described functions exists and is included within various aspects of the present disclosure. In some aspects of the disclosure, the computer-readable medium  306  may store computer-executable code comprising instructions configured to perform various processes described herein. The instructions included in the computer-readable medium  306  are provided as non-limiting examples. Other instructions configured to carry out the described functions exist and are included within various aspects of the present disclosure. 
       FIG. 4  is a diagram illustrating an example of a hardware implementation  400  for a scheduled entity  204  according to aspects of the present disclosure. Scheduled entity  204  may employ a processing system  414 . Scheduled entity  204  may be implemented with a processing system  414  that includes one or more processors  404 . Examples of processors  404  include microprocessors, microcontrollers, DSPs, FPGAs, PLDs, state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, scheduled entity  204  may be configured to perform any one or more of the functions described herein. That is, the processor  404 , as utilized in scheduled entity  204 , may be used or configured to implement any one or more of the processes and methods described herein, for example, in  FIGS. 12-18 . 
     In this example, the processing system  414  may be implemented with a bus architecture, represented generally by the bus  402 . The bus  402  may include any number of interconnecting buses and bridges depending on the specific application of the processing system  414  and the overall design constraints. The bus  402  communicatively couples together various circuits including one or more processors (represented generally by the processor  404 ), a memory  405 , and computer-readable media (represented generally by the computer-readable medium  406 ). The bus  402  may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits. A bus interface  408  provides an interface between the bus  402  and a transceiver  410 . The transceiver  410  provides a communication interface or a means for communicating with various other apparatuses over a transmission medium. Depending upon the nature of the apparatus, a user interface  412  (e.g., keypad, display, speaker, microphone, joystick) may also be provided. 
     At least one processor  404  is responsible for managing the bus  402  and general processing, including the execution of software stored on the computer-readable medium  406 . The software, when executed by the processor  404 , causes the processing system  414  to perform the various functions described below for any particular apparatus. The computer-readable medium  406  and the memory  405  may also be used for storing data that is manipulated by the processor  404  when executing software. In some aspects of the disclosure, the computer-readable medium  406  may include communication instructions  452 . The communication instructions  452  may include instructions for performing various operations related to wireless communication (e.g., signal reception and/or signal transmission) as described herein. In some aspects of the disclosure, the instructions  452  may include code for configuring the scheduled entity to perform sidelink communication as described in relation to  FIGS. 12-18 . In some aspects of the disclosure, the computer-readable medium  406  may include processing instructions  454 . The processing instructions  454  may include instructions for performing various operations related to signal processing (e.g., processing a received signal and/or processing a signal for transmission) as described herein. In some aspects of the disclosure, the processing instructions  454  may include code for configuring the scheduled entity to perform sidelink communication as described in relation to  FIGS. 12-18 . 
     At least one processor  404  may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium  406 . The computer-readable medium  406  may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., a CD or a DVD), a smart card, a flash memory device (e.g., a card, a stick, or a key drive), a RAM, a ROM, a PROM, an EPROM, an EEPROM, a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium  406  may reside in the processing system  414 , external to the processing system  414 , or distributed across multiple entities including the processing system  414 . The computer-readable medium  406  may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system. 
     In some aspects of the disclosure, at least one processor  404  may include a communication circuit  440 . The communication circuit  440  may include one or more hardware components that provide the physical structure that performs various processes related to wireless communication (e.g., signal reception and/or signal transmission) as described herein. In some aspects of the disclosure, the processor  404  may also include a processing circuitry that include one or more hardware components that provide the physical structure that performs various processes related to signal processing (e.g., processing a received signal and/or processing a signal for transmission) as described herein. In some aspects of the disclosure, the processor  404  may include a sidelink communication block  440 , an uplink/downlink (UL/DL) communication block  442 , and a sidelink interference control block  446 . The sidelink communication block  440  may be configured to perform various sidelink communication processes and functions as described in relation to  FIGS. 7-18 . The UL/DL communication block  442  may be configured to perform UL/DL communication with a scheduling entity  202  as described in  FIGS. 7-18 . The sidelink interference control block  446  may be configured to perform sidelink interference mitigation processes and functions as described in relation to  FIGS. 7-18 . 
     The circuitry included in the processor  404  is provided as non-limiting examples. Other means for carrying out the described functions exists and is included within various aspects of the present disclosure. In some aspects of the disclosure, the computer-readable medium  406  may store computer-executable code comprising instructions configured to perform various processes described herein. The instructions included in the computer-readable medium  406  are provided as non-limiting examples. Other instructions configured to carry out the described functions exist and are included within various aspects of the present disclosure. 
     According to various aspects of the disclosure, wireless communication may be implemented by dividing transmissions, in time, into frames, wherein each frame may be further divided into subframes. These subframes may be DL-centric, UL-centric, or sidelink-centric, as described below. For example,  FIG. 5  is a diagram showing an example of a DL-centric subframe  500 , so called because a majority (or, in some examples, a substantial portion) of the subframe includes DL data. The DL-centric subframe may include a control portion  502 . The control portion  502  may exist in the initial or beginning portion of the DL-centric subframe  500 . The control portion  502  may include various scheduling information and/or control information corresponding to various portions of the DL-centric subframe. In some configurations, the control portion  502  may include a physical DL control channel (PDCCH), as indicated in  FIG. 5 . Additional description related to the PDCCH is provided further below with reference to various other drawings. The DL-centric subframe may also include a DL data portion  504 . The DL data portion  504  may sometimes be referred to as the payload, traffic, or data portion of the DL-centric subframe. The DL data portion  504  may include the communication resources utilized to communicate DL data from the scheduling entity  202  (e.g., eNB) to the scheduled entity  204  (e.g., UE). In some configurations, the DL data portion  504  may be a physical DL shared channel (PDSCH). 
     The DL-centric subframe may also include a common UL portion  506 . The common UL portion  506  may sometimes be referred to as an UL burst, a common UL burst, and/or various other suitable terms. The common UL portion  506  may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the common UL portion  506  may include feedback information corresponding to the control portion  502  and/or DL data portion  504 . Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information. The common UL portion  506  may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information. As illustrated in  FIG. 5 , the end of the DL data portion  504  may be separated in time from the beginning of the common UL portion  506 . This time separation may sometimes be referred to as a gap, a guard period, a guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the scheduled entity  204  (e.g., UE)) to UL communication (e.g., transmission by the scheduled entity  204  (e.g., UE)). One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein. 
       FIG. 6  is a diagram  600  showing an example of an UL-centric subframe, so called because a majority (or, in some examples, a substantial portion) of the subframe includes UL data. The UL-centric subframe may include a control portion  602 . The control portion  602  may exist in the initial or beginning portion of the UL-centric subframe. The control portion  602  in  FIG. 6  may be similar to the control portion  502  described above with reference to  FIG. 5 . The UL-centric subframe may also include an UL data portion  604 . The UL data portion  604  may sometimes be referred to as the payload, traffic, or data portion of the UL-centric subframe. The UL data portion  604  may include the communication resources utilized to communicate UL data from the scheduled entity  204  (e.g., UE) to the scheduling entity  202  (e.g., eNB). In some configurations, the control portion  602  may include a physical UL shared channel (PUSCH). As illustrated in  FIG. 6 , the end of the control portion  602  may be separated in time from the beginning of the UL data portion  604 . This time separation may sometimes be referred to as a gap, guard period, guard interval, and/or various other suitable terms. This separation or time gap provides time for the switch-over from DL communication (e.g., reception operation by the scheduled entity  204  (e.g., UE)) to UL communication (e.g., transmission by the scheduled entity  204  (e.g., UE)). The UL-centric subframe may also include a common UL portion  606 . The common UL portion  606  in  FIG. 6  may be similar to the common UL portion  506  described above with reference to  FIG. 5 . The common UL portion  606  may additionally or alternatively include information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric subframe, and alternative structures having similar features may exist without necessarily deviating from the aspects described herein. 
     In some circumstances, two or more scheduled entities  204  (e.g., UEs) may communicate with each other using sidelink signals. Generally, a sidelink signal may refer to a signal communicated from one scheduled entity  204  (e.g., UE 1 ) to another scheduled entity  204  (e.g., UE 2 ) without relaying that communication through the scheduling entity  202  (e.g., eNB or base station), even though the scheduling entity  202  (e.g., eNB) may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum). Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh, and/or various other suitable applications. 
     However, communication using sidelink signals may increase the relative likelihood of signal interference in certain circumstances. For example, without the aspects described in the present disclosure, interference may occur between the sidelink signals and the DL/UL control/scheduling information of nominal traffic (e.g., communication between a scheduled entity and a scheduling entity). That is, the DL/UL control/scheduling information of nominal traffic may not be as well protected. As another example, without the aspects described in the present disclosure, interference may occur between sidelink signals or channels originating from different scheduled entities  204  (e.g., UEs). That is, concurrently transmitted sidelink signals may collide and/or interfere with each other. Aspects of the present disclosure provide for an interference management scheme for concurrent sidelink signals and sidelink-centric subframes that facilitate sidelink interference management. 
       FIG. 7  is a diagram illustrating an example of a sidelink-centric subframe  700  according to some aspects of the present disclosure. In some configurations, this sidelink-centric subframe may be utilized for broadcast communication. A broadcast communication may refer to a transmission by one scheduled entity  204   b  (e.g., UE 1 ) to a group of scheduled entities  204   a  (e.g., UE 2 -UE N ). In this example, the sidelink-centric subframe includes a control portion  702 , which may include a PDCCH or a downlink control channel. In some aspects, the control portion  702  may be similar to the control portion  502  (e.g., PDCCH) described in greater detail above with reference to  FIG. 5 . Additionally or alternatively, the control portion  702  may include grant information related to the sidelink signal or sidelink communication. The grant information may indicate the resource (e.g., time and/or frequency resources) assignment used for sidelink communication, modulation and coding scheme (MCS), multiple-input and multiple-output (MIMO) configuration (if used), etc. Non-limiting examples of grant information may include generic grant information and link-specific grant information. Link-specific grant information may refer to information that enables a specific sidelink communication to occur between two particular scheduled entities  204  (e.g., UEs). In comparison, generic grant information may refer to information that generally enables sidelink communications to occur within a particular cell, without specifying a particular sidelink communication. 
     Notably, as illustrated in  FIG. 7 , the control portion  702  may be included in the beginning or initial portion of the sidelink-centric subframe. By including the control portion  702  in the beginning or initial portion of the sidelink-centric subframe, the likelihood of interfering with the control portions  502 ,  602  of DL-centric and UL-centric subframes of nominal traffic is minimized or reduced. In other words, because the DL-centric subframe, the UL-centric subframe, and the sidelink-centric subframe have their DL control information communicated during a common portion of their respective subframes, the likelihood of interference between the DL control information and the sidelink signals is minimized or reduced. That is, the control portions  502 ,  602  of DL-centric and UL-centric subframes (of nominal traffic) are relatively better protected. 
     The sidelink-centric subframe  700  may also include a source transmit signal (STS) portion  704 . The STS portion  704  may be a portion of the subframe during which one scheduled entity  204  (e.g., UE) communicates an STS indicating a requested duration of time to keep a sidelink channel available for a sidelink signal or communication. One of ordinary skill in the art will understand that the STS may include additional or alternative various information without necessarily deviating from the scope of the present disclosure. In some configurations, the STS may include a group destination identifier (ID). The group destination ID may correspond to a group of devices or scheduled entities that are intended to receive the STS. In some configurations, the STS may include a specific destination ID that corresponds to a predetermined device or scheduled entity. In some configurations, the STS may indicate a duration of the sidelink transmission, a reference signal to enable channel estimation and RX-yielding, a modulation and coding scheme (MCS) indicator, and/or various other information. 
     For the sake of completeness, the following information is provided regarding RX-yielding. It is assumed that two sidelinks exist simultaneously. Sidelink 1  is between UE A  and UE B , and Sidelink 2  is between UE C  and UE D . Assume also that Sidelink 1  has a higher priority than Sidelink 2 . If UE A  and UE C  concurrently transmit their STSs, UE D  will refrain from transmitting a DRS, because Sidelink 1  has a higher priority than Sidelink 2 . Accordingly, the relatively lower priority sidelink (Sidelink 2 ) yields (i.e., RX-yielding) communication of the DRS under these circumstances. 
     A scheduled entity  204  (e.g., UE 1 ) may transmit an STS (with RX-yielding) to one or more other scheduled entities  204  (e.g., UE 2 , UE 3 ) to request that the other scheduled entities  204  (e.g., UE 2 , UE 3 ) refrain from using the sidelink channel for the requested duration of time, thereby leaving the sidelink channel available for that scheduled entity  204  (e.g., UE 1 ). By transmitting the STS, the scheduled entity  204  (e.g., UE 1 ) can effectively reserve the sidelink channel for sidelink communication. This enables distributed scheduling and management of interference that might otherwise occur from another sidelink communication from other scheduled entities  204  (e.g., UE 2 , UE 3 ). Put another way, because the other scheduled entities  204  (e.g., UE 2 , UE 3 ) are informed that UE 1  will be transmitting for the requested period of time, the likelihood of interference between sidelink signals is reduced. 
     The sidelink-centric subframe  700  may also include a sidelink data portion  706 . The sidelink data portion  706  may sometimes be referred to as the payload, traffic, or sidelink-burst of the sidelink-centric subframe. The sidelink data portion  706  may include the communication resources (e.g., time and/or frequency resources) utilized to communicate sidelink data from one scheduled entity  204  (e.g., UE 1 ) to one or more other scheduled entities  204  (e.g., UE 2 , UE 3 ). In some configurations, the sidelink data portion  706  may include a physical sidelink shared channel (PSSCH), as indicated in  FIG. 7 . In some examples, the transmitting scheduled entity  204  may transmit sidelink control information over the resources allocated (e.g., sidelink grants) by the PDCCH  702  before transmitting the sidelink data  706 . The sidelink control information provides the information or parameters used by the receiving sidelink device to receive and decode the sidelink data. 
     The sidelink-centric subframe  700  may also include a common UL portion  708 . In some aspects, the common UL portion  708  may be similar to the common UL portion  506 ,  606  described above with reference to  FIGS. 5-6 . Notably, as illustrated in  FIG. 7 , the common UL portion  708  may be included in the end portion of the sidelink-centric subframe. By including the common UL portion  708  in the end portion of the sidelink-centric subframe, the likelihood of interfering with the common UL portion  506 ,  606  of DL-centric and UL-centric subframes of nominal traffic is minimized or reduced. In other words, because the DL-centric subframe, the UL-centric subframe, and the sidelink-centric subframe have their common UL portions  506 ,  606 ,  708  communicated during a similar portion of their respective subframe, the likelihood of interference between those common UL portions  506 ,  606 ,  708  is minimized or reduced. That is, the common UL portions  506 ,  606  of DL-centric and UL-centric subframes (of nominal traffic) are relatively better protected, and less likely to be interfered by DL data. 
       FIG. 8  is a diagram  800  illustrating an example of sidelink-centric subframes extending across a plurality of TTIs. In some configurations, these sidelink-centric subframes may be utilized for broadcast communication. Generally, a TTI refers to a schedulable interval of time that contains at least one transport block. Although the example illustrated in  FIG. 8  shows three TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ), one of ordinary skill in the art will understand that any plural number of TTIs may be implemented without deviating from the scope of the present disclosure. The first TTI (e.g., TTI N ) may include a control portion  802  (e.g., PDCCH, as described in greater detail above) and an STS portion  804  (as also described in greater detail above). The STS portion  804  may indicate a duration that extends across more than one TTI (e.g., TTI N , TTI N+1 , TTI N+2 ) for sidelink communication. In other words, the STS may indicate a requested duration of time to keep the sidelink channel available for sidelink signals, and that requested duration may extend until the end of the last TTI (e.g., TTI N+2 ) of a plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ). Therefore, although the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ) each include a sidelink data portion  806 ,  812 ,  818 , not every TTI requires the STS portion  804 . In this example, only the first TTI includes the STS portion  804 . By not including the STS portion  804  in every TTI of the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ), the overall amount of overhead is relatively lower than it would be otherwise (e.g., if the STS portion  804  was included in every TTI). By reducing overhead, relatively more of the TTIs (e.g., TTI N+1 , TTI N+2 ) lacking the STS portion  804  can be utilized for communication of the sidelink data  812 ,  818 , which thereby increases relative throughput or bandwidth efficiency. 
     The STS portion  804  may be followed by a sidelink data portion  806  (which is described in greater detail above with reference to the sidelink data portion  706  in  FIG. 7 ). The sidelink data portion  806  may be followed by the common UL portion  808  (which is described in greater detail above with reference to the common UL portion  708  in  FIG. 7 ). In the example illustrated in  FIG. 8 , every TTI (e.g., TTI N+1 , TTI N+2 ) following the first TTI (e.g., TTI N ) includes a control portion  810 ,  816  at an initial/beginning portion of each subframe/TTI and a common UL portion  814 ,  820  at the end portion of each subframe/TTI. By providing the control portion  810 ,  816  at the initial/beginning of each subframe/TTI and providing the common UL portion  814 ,  820  at the end portion of each subframe/TTI, the sidelink-centric subframes have a structure that minimizes the likelihood of interference with DL/UL control/scheduling information of nominal traffic (as described in greater detail above). In some examples, a gap or guard band may be provided between the common UL portion and the control portion such that the scheduled entity is provided with sufficient time to reconfigure its circuitry between a receiving mode and a transmitting mode. 
       FIG. 9  is a diagram illustrating another example of a sidelink-centric subframe  900  according to some aspects of the present disclosure. In some configurations, this sidelink-centric subframe may be utilized for a unicast communication. A unicast communication may refer to a transmission by a scheduled entity  204  (e.g., UE 1 ) to a particular scheduled entity  204  (e.g., UE 2 ). Description corresponding to aspects of the control portion  902 , sidelink data portion  910 , and common UL portion  914  are provided above with reference to preceding figures, and therefore will not be repeated to avoid redundancy. 
     The example of the sidelink-centric subframe  900  illustrated in  FIG. 9  includes a direction selection signal (DSS)  904 , and a source transmit signal (STS)  906 . Additional description regarding the STS signal is provided above (e.g., with reference to  FIG. 7 ), and therefore will not be repeated to avoid redundancy. The content of the DSS is substantially similar to that of the STS. However, in contrast to the STS signal described above with respect to  FIG. 7 , the DSS  904  and STS  906  described herein with reference to  FIG. 9  and utilized for unicast communication, may include a destination ID instead of a group destination ID. The destination ID may indicate the specific apparatus or scheduled entity destined to receive the STS/DSS. 
     For sidelink communication, a primary device may transmit a DSS during the DSS portion  904 , and a non-primary device may transmit an STS during the STS portion  906 . A primary device may refer to a device that has priority access to the sidelink channel over the non-primary device. During an association phase, one device may be selected as the primary device and another device may be selected as the non-primary (e.g., secondary) device. In some configurations, the primary device may be a relay device that relays a signal from a non-relay device to another device, such as a scheduling entity  202  (e.g., eNB). The relay device may experience relatively less path loss (when communicating with the scheduling entity  202  (e.g., eNB)) relative to the path loss experienced by the non-relay device. 
     During the DSS portion  904 , the primary device may transmit a DSS, and the non-primary device listens for the DSS from the primary device. One the one hand, if the non-primary device detects a DSS during the DSS portion  904 , then the non-primary device will not transmit an STS during the STS portion  906 . On the other hand, if the non-primary device does not detect a DSS during the DSS portion  904 , then the non-primary device may transmit an STS during the STS portion  906 . A time gap (e.g., a guard interval, guard band, etc.) between DSS and STS allows the non-primary device to transition from a listening/receiving state (during DSS  904 ) to a transmitting state (during STS  906 ). 
     If the sidelink channel is available for the requested duration of time, an apparatus that receives the DSS/STS may communicate a destination receive signal (DRS) during the DRS portion  908 . The DRS may indicate the availability of the sidelink channel for the requested duration of time. The DRS may additionally or alternatively include other information, such as a source ID, a duration of the transmission, a signal to interference plus noise ratio (SINR) (e.g., of the received reference signal (RS) from the source device), an RS to enable TX-yielding, CQI information, and/or various other suitable types of information. The exchange of DSS/STS and DRS (DSS/STS-DRS handshaking) enables the scheduled entities  204  (e.g., UEs) performing sidelink communication to negotiate the availability of the sidelink channel prior to the communication of the sidelink data signal or payload, thereby minimizing the likelihood of interfering sidelink signals. In other words, without the DSS/STS and DRS, two or more scheduled entities  204  (e.g., UEs) may concurrently transmit sidelink signals using the same resources (e.g., time and/or frequency resources) of the sidelink data portion  910 , thereby causing a collision and resulting in avoidable retransmissions. 
     For the sake of completeness, the following information is provided regarding TX-yielding. Assume (again) that two sidelinks exist. Sidelink 1  is between UE A  and UE B , and Sidelink 2  is between UE C  and UE D . Assume (again) that Sidelink 1  has a higher priority than Sidelink 2 . The priority of the sidelinks may be determined by a scheduling entity  202 . If UE A  and UE C  concurrently transmit their respective DSSs, UE B  will transmit a DRS (because Sidelink 1  has relatively higher priority than Sidelink 2 ). In the DRS, UE B  may include an RS or a flag that is configured to inform UE C  that it may interfere with the sidelink communication (e.g., sidelink signal in the sidelink data portion  910 ) if it transmits during a particular period of time. Accordingly, by receiving this RS, UE C  will refrain from transmitting for that particular period of time (e.g., at least for the duration of the sidelink communication of Sidelink 1 ). Accordingly, the relatively lower priority sidelink (Sidelink 2 ) yields communication (i.e., TX-yielding) for a particular period of time under these circumstances. 
     As described in greater detail above, the sidelink signal or payload may be communicated in the sidelink data portion  910  of the sidelink-centric subframe. In some configurations, the MCS of the sidelink signal communicated in the sidelink data portion  910  may be selected based on the CQI information included in the DRS. After communicating the sidelink signal in the sidelink data portion  910 , acknowledgment information may be communicated between the scheduled entities  204  (e.g., UEs). Such acknowledgment information may be communicated in the sidelink acknowledgment portion  912  of the sidelink-centric subframe. Non-limiting examples of such acknowledgment information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of acknowledgment information. For example, after receiving and successfully decoding a sidelink signal from UE 1  in the sidelink data portion  910 , UE 2  may transmit an ACK signal to UE 1  in the sidelink acknowledgment portion  912  of the sidelink-centric subframe. In some configurations, the sidelink acknowledgment portion  912  may include a physical sidelink HARQ indicator channel (PSHICH), as indicated in  FIG. 9 . The sidelink acknowledgment portion  912  may be separated in time from the common UL portion  914  by a guard period. This separation provides time for the switch-over from DL communication to UL communication. 
       FIG. 10  is a diagram  1000  illustrating an example of sidelink-centric subframes extending across a plurality of TTIs. In some configurations, these sidelink-centric subframes may be utilized for unicast communications. Although the example illustrated in  FIG. 10  shows three TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ), one of ordinary skill in the art will understand that any plural number of TTIs may be implemented without deviating from the scope of the present disclosure. The first TTI (e.g., TTI N ) may include the control portion  1002  (e.g., PDCCH, as described in greater detail above), a DSS portion  1004 , an STS portion  1006 , and a DRS portion  1008  (as also described in greater detail above). 
     The DSS communicated during the DSS portion  1004  and/or the STS communicated during the STS portion  1006  may indicate a duration that extends across more than one TTI (e.g., TTI N , TTI N+1 , TTI N+2 ) for sidelink communication. In other words, the DSS/STS indicates a requested duration of time to keep the sidelink channel available for sidelink signals, and that requested duration extends until the end of the last TTI (e.g., TTI N+2 ) of the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ). If the sidelink channel is available for that requested duration of time, then the DRS may be communicated in the DRS portion  1008  (as described in greater detail above). Although the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ) each include a sidelink data portion  1010 ,  1016 ,  1022 , not every TTI has a DSS/STS portion. By not including a DSS/STS portion in every TTI of the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ), the overall amount of communication overhead is relatively lower than it would otherwise (if DSS and/or STS was/were included in every TTI). By reducing overhead, relatively more time of the TTIs (e.g., TTI N+1 , TTI N+2 ) lacking DSS and/or STS can be utilized for communication of the sidelink data  1016 ,  1022 , which thereby increases relative throughput. 
     DSS  1004 , STS  1006 , and DRS  1008  may be followed by a first sidelink data portion  1010  (which is described in greater detail above with reference to the sidelink data portion  706  in  FIG. 7 ). The sidelink data portions  1010 ,  1016 ,  1022  may each be followed by a common UL portion  1012 ,  1018 ,  1026  (which are described in greater detail above with reference to the common UL portion  708  in  FIG. 7 ). In the example illustrated in  FIG. 10 , every TTI (e.g., TTI N+1 , TTI N+2 ) following the first (e.g., TTI N ) includes a control portion  1014 ,  1020  at an initial/beginning portion of each subframe/TTI and a common UL portion  1018 ,  1026  at the end portion of each subframe/TTI. By providing the control portion  1014 ,  1020  at the initial/beginning of each subframe/TTI and providing the common UL portion  1018 ,  1026  at the end portion of each subframe/TTI, the sidelink-centric subframes have a structure that minimizes the likelihood of interference with DL/UL control/scheduling information of nominal traffic (as described in greater detail above). 
     In the example illustrated in  FIG. 10 , the sidelink-centric subframes include a single sidelink acknowledgment portion  1024  in a last/final TTI (e.g., TTI N+2 ) of the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ). The sidelink acknowledgment portion  1024  may be separated in time from a common UL portion  1026  by a guard period. This separation provides time for the switch-over from DL communication to UL communication. The acknowledgment information communicated in the sidelink acknowledgment portion  1024  in the last/final TTI (e.g., TTI N+2 ) may correspond to the sidelink signals included in one or more preceding sidelink data portions  1010 ,  1016 ,  1022 . For example, the sidelink acknowledgment portion  1024  may include a HARQ identifier corresponding to sidelink signals communicated throughout the sidelink data portions  1010 ,  1016 ,  1022  of the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ). Because the sidelink acknowledgment portion  1024  is not included in every TTI (e.g., TTI N , TTI N+1 ), the overall amount of overhead is relatively lower than it would be otherwise (e.g., if sidelink acknowledgment portion  1024  were included in every TTI). By reducing overhead, relatively more of the TTIs (e.g., TTI N , TTI N+1 ) lacking the sidelink acknowledgment portion  1024  can be utilized for communication of sidelink data or payload, which thereby increases relative throughput. However, one of ordinary skill in the art will readily understand that the example illustrated in  FIG. 10  is non-limiting and alternative configurations may exist without necessarily deviating from the scope of the present disclosure. 
       FIG. 11  is a diagram  1100  illustrating an example of such an alternative configuration. Various aspects illustrated in  FIG. 11  (e.g., control portions  1102 ,  1116 ,  1124 ; DSS portion  1104 ; STS portion  1106 ; DRS portion  1108 ; and common UL portions  1114 ,  1122 ,  1130 ) are described above with reference to  FIG. 10  and therefore will not be repeated here to avoid redundancy. An aspect in which the example illustrated in  FIG. 11  may differ from the example illustrated in  FIG. 10  is that the example in  FIG. 11  includes a sidelink acknowledgment portion  1112 ,  1120 ,  1128  (shown as PSHICH in  FIG. 11  for example) in every TTI of the plurality of TTIs (e.g., TTI N , TTI N+1 , TTI N+2 ). The sidelink acknowledgment portion may be separated in time from a common UL portion by a guard period. This separation provides time for the switch-over from DL communication to UL communication. For example, each sidelink acknowledgment portion  1112 ,  1120 ,  1128  may respectively communicate acknowledgment information corresponding to a sidelink signal or payload included in the corresponding sidelink data portion  1110 ,  1118 ,  1126  in its TTI. By receiving acknowledgment information corresponding to the sidelink signal in that particular or same TTI, the scheduled entity  204  (e.g., UE) may obtain relatively better specificity regarding the communication success of each sidelink signal per TTI. For example, if only one sidelink signal in a single sidelink data portion (e.g., sidelink data portion  1110 ) is not successfully communicated, retransmission can be limited to only the affected sidelink portion (e.g., sidelink data portion  1110 ) without the burden of retransmitting unaffected sidelink portions (e.g., other sidelink data portions  1118 ,  1126 ). 
       FIG. 12  is a diagram illustrating an interference scenario between sidelinks extending across multiple subframes/TTIs. For example, a first scheduled entity  204  (e.g., UE A ) transmits sidelink data to a second scheduled entity  204  (e.g., UE B ) using a first sidelink  1200  across multiple TTIs (two exemplary TTIs shown in  FIG. 12 ). The DSS/STS-DRS handshaking  1202  in the first TTI (e.g., TTI N ) informs neighboring scheduled entities  204  (e.g., UE C , UE D ) of channel occupation by the first sidelink for a certain number of TTIs. In the second TTI (e.g., TTI N+1 ), a third scheduled entity  204  (e.g., UE C ) may have data to transmit to a fourth scheduled entity  204  (e.g., UE D ). Therefore, UE C  and UE D  may perform DSS/STS-DRS handshaking  1204  during TTI N+1  to establish a second sidelink  1203 . Based on the DSS/STS-DRS handshaking  1202  between UE A  and UE B , UE C  may determine that its DSS transmission will not significantly interfere with UE B &#39;s reception of sidelink data  1206  of the first sidelink. UE C  could have received UE B &#39;s DRS in the previous subframe, from which UE C  can determine if it needs to perform Tx-yielding. Upon receiving UE C &#39;s DSS, UE D  may determine that it needs not perform Rx-yielding and thus transmits DRS  1208  to UE C . UE D  could have determined that its transmission will not cause interference based on the DSS and/or STS of first sidelink  1200  in a previous subframe. However, in this case, UE C  may not be able to receive and/or decode the DRS  1208  due to the simultaneously ongoing sidelink data  1206  transmission on the first sidelink  1200 . 
     Aspects of the present disclosure provide solutions that can reduce or avoid the sidelink interference problems described in relation to  FIG. 12 .  FIG. 13  is a diagram illustrating a destination receive signal (DRS) protection scheme using data puncturing according to some aspects of the present disclosure. Referring to  FIG. 13 , a first scheduled entity  204  (e.g., UE A ) transmits data to a second scheduled entity  204  (e.g., UE B ) using a first sidelink  1300  across multiple TTIs (e.g., two exemplary TTIs shown in  FIG. 13 ). The DSS/STS-DRS handshaking  1302  in the first TTI (e.g., TTI N ) informs neighboring scheduled entities  204  (e.g., UE C  and UE D ) of channel occupation by the first sidelink  1300  for a certain number of TTIs. In the second TTI (e.g., TTI N+1 ), a third scheduled entity  204  (e.g., UE C ) may have data to transmit to a fourth scheduled entity  204  (e.g., UE D ). Therefore, UE C  and UE D  may perform DSS/STS-DRS handshaking  1304  during TTI N+1  to establish a second sidelink  1305 . 
     In the second TTI, UE A  may puncture its PSSCH data  1306  (sidelink data portion or payload) during a predetermined time period  1308  when UE C  receives the DRS  1310  from UE D . That is, the predetermined time period  1308  overlaps the DRS  1310 . Puncturing in this example means that UE A  does not transmit data during the predetermined time period  1308  such that UE C  can receive the DRS from UE D  without being interfered by transmission of the first sidelink  1300 . In one aspect of the disclosure, referring to  FIG. 14 , UE A  may encode  1402  its sidelink data using a certain coding technique (e.g., convolutional coding) to produce coded data that can be modulated for sidelink transmission. Then, puncturing  1404  may take certain data bit(s) out of the coded data according to a predetermined puncturing pattern. For example, puncturing may include, dropping, discarding, or not transmitting certain coded bit(s) that may overlap the DRS portion  1310 . The location and timing of DRS in each subframe/TTI is known because this information may be included in the sidelink grant information broadcasted (e.g., PDCCH) by a scheduling entity  202  or base station (e.g., eNB). Therefore, the puncturing pattern may be determined based on the DRS timing. 
     In various aspects of the disclosure, UE A  may puncture data in all or some of the TTIs after the first TTI (e.g., TTI N ) in any predetermined order. For example, the UE A  may puncture its sidelink data in a certain TTI when it detects a sidelink channel nearby that may be interfered by its sidelink data transmission. 
       FIG. 15  is a diagram illustrating an example of a destination receive signal (DRS) protection scheme using retransmission according to some aspects of the present disclosure. Referring to  FIG. 15 , a first scheduled entity  204  (e.g., UE A ) transmits data to a second scheduled entity  204  (e.g., UE B ) using a first sidelink  1500  across multiple TTIs (e.g., two TTIs shown in  FIG. 15 ). The DSS/STS-DRS handshaking  1502  in the first TTI (e.g., TTI N ) informs neighboring scheduled entities  204  (e.g., UE C  and UE D ) of channel occupation by the first sidelink  1500  for a certain number of TTIs. In the second TTI (e.g., TTI N+1 ), a third scheduled entity  204  (e.g., UE C ) may have data to transmit to a fourth scheduled entity  204  (e.g., UE D ). Therefore, UE C  and UE D  may perform DSS/STS-DRS handshaking  1504  during TTI N+1  to establish a second sidelink  1505 . UE C  may monitor the DSS, STS and/or DRS of other sidelinks (e.g., first sidelink  1500 ) to determine whether UE A  will transmit sidelink data on the first sidelink  1500 . If UE A  transmits sidelink data during TTI N+1 , UE C  may be blocked or interfered by the first sidelink  1500  to receive and/or decode the DRS  1512  (first DRS) in the time period  1514  that overlaps the DRS transmission. When UE C  is aware that neighboring UE A  will be transmitting sidelink data in the second TTI (e.g., TTI N+1 ), UE C  may include a flag in its DSS signal  1506  to indicate potential sidelink interference. The flag may be one or more bits configured to request UE D  to retransmit all or some of the information of DRS  1512  during the same TTI (e.g., TTI N+1 ). For example, UE D  in response to the flag, may retransmit DRS-equivalent information (second DRS) with a CQI in the PSHICH  1510  (or an acknowledgment portion of the TTI) where there is no sidelink data transmission from UE A . In the case that UE C  cannot receive and/or decode the DRS  1512 , UE C  will not transmit data during this TTI. However, UE C  can send its payload data in subsequent TTI(s). 
     In some aspects of the disclosure, an apparatus (e.g., UE) may be configured to perform either one or both of the DRS protection schemes described above in relation to the  FIGS. 13 and 15 . That is, the apparatus may be configured to puncture its sidelink data during a predetermined time period to reduce interference to a DRS transmission of a different sidelink, and/or retransmit DRS-equivalent information (e.g., a second DRS) with a CQI in a PSHICH where there is no data transmission from an otherwise interfering sidelink. 
       FIG. 16  is a flowchart illustrating a method  1600  of sidelink interference management according to some aspects of the present disclosure. The method of  FIG. 16  may be implemented or executed using any of the scheduled entities  204  or UEs to manage sidelink interference for example as described in relation to  FIGS. 13-15 . At block  1602 , a scheduled entity  204  may utilize the communication interface  410  to receive, from a scheduling entity, sidelink grant information in a downlink control channel (e.g., PDCCH). For example, the scheduling entity may be any of the eNBs or scheduling entities described in  FIGS. 1-3  or another scheduled entity. 
     At block  1604 , the scheduled entity may utilize the sidelink communication block  440  to transmit a DSS in a first TTI utilizing a first sidelink to a first scheduled entity according to the sidelink grant information. The DSS is configured to indicate a requested duration of time to keep the first sidelink available for a plurality of TTIs including the first TTI. In one example, the scheduled entity may be UE A  of  FIG. 13 or 15  that transmits a DSS to UE B  using the first sidelink (e.g., sidelink  1300  or  1500 ). In another example, the scheduled entity may be the UE C  of  FIG. 13 or 15  that transmits a DSS to UE D  using the second sidelink (e.g., sidelink  1305  or  1505 ). 
     At block  1606 , the scheduled entity may utilize the sidelink interference control block  446  to mitigate interference between the first sidelink and a second sidelink established between other scheduled entities different from the scheduled entity and the first scheduled entity. In one example, when the first sidelink is the sidelink  1300  or  1500 , the second sidelink may be the sidelink  1305  or  1505 . In another example, when the first sidelink is the sidelink  1305  or  1505 , the second sidelink may be the sidelink  1300  or  1500 . In one example, to mitigate interference between the sidelinks, the scheduled entity (e.g., UE A  of  FIG. 13 ) may configure the sidelink interference control block  446  to puncture its sidelink data during a first time period (e.g., time period  1308 ) of at least one of the TTIs, wherein the first time period overlaps with a first DRS (e.g., DRS  1310 ) of the second sidelink. In another example, to mitigate interference between the sidelinks, the scheduled entity (e.g., UE C  of  FIG. 15 ) may configure the sidelink interference control block to include a flag in its DSS signal to receive, from the first scheduled entity (e.g., UE D ) in the first TTI, a retransmission of a second DRS in a second time period (e.g., time period  1510 ) that is not interfered by the second sidelink. 
       FIG. 17  is a flowchart illustrating a method  1700  of sidelink interference management according to some aspects of the present disclosure. The method of  FIG. 17  may be implemented or executed using any of the scheduled entities  204  or UEs to manage sidelink interference, for example, as described in relation to  FIG. 13 . At block  1702 , a scheduled entity  204  (e.g., UE A  of  FIG. 13 ) utilizes the communication interface  410  to receive, from a scheduling entity, sidelink grant information in a downlink control channel (e.g., PDCCH). For example, the scheduling entity may be any of the eNBs or scheduling entities described in  FIGS. 1-3  or another scheduled entity. At block  1704 , the scheduled entity may utilize the sidelink communication block  440  to communicate, with a first scheduled entity (e.g., UE B  of  FIG. 13 ) different from the scheduling entity, sidelink data (e.g., PSSCH data  1306 ) utilizing a first sidelink (e.g., first sidelink  1300 ) across a plurality of TTIs, according to the sidelink grant information. At block  1706 , the scheduled entity (e.g., UE A ) may utilize the sidelink interference control block  446  configured to puncture its sidelink data during a predetermined time period (e.g., time period  1308  of  FIG. 13 ) of at least one of the TTIs, wherein the time period overlaps with a DRS (e.g., DRS  1310  of  FIG. 13 ) of a second sidelink for communication between other scheduled entities (e.g., UE C  and UE D ) different from the first scheduled entity (e.g., UE B ). Therefore, interference with the DRS may be reduced or avoided. 
       FIG. 18  is a flowchart illustrating a method  1800  of sidelink interference management according to some aspects of the present disclosure. The method of  FIG. 18  may be implemented or executed using any of the scheduled entities  204  or UEs to manage sidelink interference, for example, as described in relation to  FIG. 15 . At block  1802 , a scheduled entity  204  (e.g., UE C  of  FIG. 15 ) utilizes the transceiver  410  to receive, from a scheduling entity, sidelink grant information in a downlink control channel (e.g., PDCCH). At block  1804 , the UE C  utilizes the sidelink interference control block  446  configured to transmit a DSS (e.g., DSS  1506  of  FIG. 15 ) during a TTI to a scheduled entity (e.g., UE D  of  FIG. 15 ) different from the scheduling entity according to the sidelink grant information. The DSS signal is configured to indicate a sidelink interference condition during a time period (e.g., time period  1514  of  FIG. 15 ) for receiving a DRS (e.g., DRS  1512  of  FIG. 15 ) from the UE D . At block  1806 , UE C  utilizes the sidelink communication block  440  and/or sidelink interference control block to receive, from UE D  in the same TTI, a retransmission (a second DRS) of the information included in the first DRS in a time period (e.g., acknowledgment portion  1510  of  FIG. 15 ) different from that for receiving the first DRS. Therefore, even if UE C  failed to receive and/or decode the first DRS  1512 , the information included in the second DRS may still be received during its retransmission for example in the acknowledgment portion  1510  (e.g., PSHICH) of the same TTI. 
     In some configurations, the term(s) ‘communicate,’ ‘communicating,’ and/or ‘communication’ may refer to ‘receive,’ ‘receiving,’ ‘reception,’ and/or other related or suitable aspects without necessarily deviating from the scope of the present disclosure. In some configurations, the term(s) ‘communicate,’ ‘communicating,’ ‘communication,’ may refer to ‘transmit,’ ‘transmitting,’ ‘transmission,’ and/or other related or suitable aspects without necessarily deviating from the scope of the present disclosure. 
     Although the examples described herein may describe certain features, operations, processes, methods, and/or aspects from the perspective of a scheduled entity  204  (e.g., UE), one of ordinary skill in the art will understand that corresponding features, operations, processes, methods, and/or aspects from the perspective of the scheduling entity  202  (e.g., base station, cell, and/or other network entity) are readily ascertainable and understood from the present disclosure and, therefore, would not deviate from the scope of the present disclosure. Several aspects of a wireless communication network have been presented with reference to an exemplary implementation. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards. By way of example, various aspects may be implemented within other systems defined by 3GPP, such as LTE, the Evolved Packet System (EPS), the Universal Mobile Telecommunication System (UMTS), and/or the Global System for Mobile (GSM). Various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2), such as CDMA2000 and/or Evolution-Data Optimized (EV-DO). Other examples may be implemented within systems employing IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system. 
     Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration.” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another—even if they do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly physically in contact with the second object. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure. 
     One or more of the components, steps, features and/or functions illustrated herein may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated herein may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware. 
     It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein. 
     The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112(f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”