Patent Description:
Mobile communications continue to evolve. A fifth generation may be referred to as <NUM>. A previous (legacy) generation of mobile communication may be, for example, fourth generation (<NUM>) long term evolution (LTE). Mobile wireless communications implement a variety of radio access technologies (RATs), such as New Radio (NR) or <NUM> flexible RAT. Use cases for NR may include, for example, extreme Mobile Broadband (eMBB), Ultra High Reliability and Low Latency Communications (URLLC) and massive Machine Type Communications (mMTC) - see <CIT> and <CIT>.

Systems, methods, and instrumentalities are disclosed for active interference management. Active interference management may be provided for designated data regions and/or superzones. UAV-specific or other designated data regions (e.g., with data zones) may enable dynamic inter-cell interference management and high reliability command & control for UAVs in interference prone environments. Data zone/region specific control channel search space may support inter-cell interference cancellation. Aggregation levels (e.g., during EPDCCH encoding) may be dependent on an interference level of a zone. Data zone specific reference signals (DS-RS) may enable UAVs connected to neighboring cells to estimate an interference channel per zone. Interference management may be provided during semi-persistent scheduling (SPS) transmissions. Reliability of Physical Downlink Control Channel (PDCCH) may be enhanced (EPDCCH), e.g., with interference assistance signaling. Uplink interference management may operate with dedicated data region/zones. A downlink control information (DCI) format may be provided for UAVs.

A WTRU may receive and decode a PDCCH transmission from a serving cell. The PDCCH transmission may include DCI, which may be used by the WTRU to determine a data region assigned to the WTRU by the serving cell. The WTRU may receive and decode one or more EPDCCH transmission from one or more neighboring cells. The EPDCCH transmissions may include interference information associated with the one or more neighboring cells. The WTRU may use the interference information to receive one or more data transmission from the serving cell.

A PDCCH of a serving cell and an EPDCCH of one or more neighboring cells may be decoded by a WTRU using blind decoding. The EPDCCH of the one or more neighboring cells may be decoded using zone specific radio network temporary identifier (ZN-RNTI). The ZN-RNTI and/or the search space may be associated with a data region assigned to a WTRU by the serving cell.

A detailed description of illustrative embodiments will now be described with reference to the various Figures. Although this description provides a detailed example of possible implementations, it should be noted that the details are intended to be exemplary and in no way limit the scope of the application.

For example, the communications systems <NUM> may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multi carrier (FBMC), and the like.

For example, the base station <NUM>14a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles.

In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE <NUM> (i.e., Wireless Fidelity (WiFi), IEEE <NUM> (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard <NUM> (IS-<NUM>), Interim Standard <NUM> (IS-<NUM>), Interim Standard <NUM> (IS-<NUM>), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

The processor <NUM><NUM> may also output user data to the speaker/microphone <NUM>, the keypad <NUM>, and/or the display/touchpad <NUM>.

The peripherals <NUM> may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor.

In an embodiment, the WRTU <NUM> may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception).

At the receiver of die receiving STA, the above described operation for the <NUM>+<NUM> configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

11af and <NUM>. 11af and <NUM>. 11n, and <NUM>. <NUM>1af supports <NUM>, <NUM> and <NUM> bandwidths in the TV White Space (TVWS) spectrum, and <NUM>1ah supports <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> bandwidths using non-TVWS spectrum.

WLAN systems, which may support multiple channels, and channel bandwidths, such as <NUM> In, <NUM>. 11ac, <NUM> laf, and <NUM>.

In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs <NUM>80a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

The CN <NUM> shown in FIG. ID may include at least one AMF 182a, 182b, at least one UPF 184a,184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b.

The SMF 183a, 183b may perform other functions, such as managing and allocating WTRU IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like.

In view of <FIG>, and the corresponding description of <FIG>, one or more, or all, of the functions described herein with regard to one or more of WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME <NUM>, SGW <NUM>, PGW <NUM>, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown).

Cellular communications may be provided for drones. Cellular infrastructure may provide coverage to drones (e.g., at various altitudes and interference levels) in addition to terrestrial WTRUs. Techniques described herein may be applicable to drones/unmanned aerial vehicles (UAVS) communicating in a cellular communication system. However, although the techniques described may be presented in terms of example communications utilized by UAVs, the techniques may also be more generally applicable to any or other types of WTRUs. The terms UE, WTRU, UAV, drone, UAV WTRU, user, etc. may be used interchangeably herein. Drone communication may be integrated to coexist with the cellular terrestrial users (e.g., terrestrial WTRUs) of existing communication systems.

Differences in the operational scenarios between drones and terrestrial users may include expected usage and operation at altitudes between <NUM> and <NUM> feet for drones and expected usage and operation at altitudes between <NUM> and <NUM> feet for terrestrial users (e.g., on average). A communication system architecture designed predominantly for terrestrial users may be adapted to drones. Traditional channel models have been developed for terrestrial systems and communication protocols have been designed based on terrestrial channel models. One or modifications of terrestrial communication systems may be modified to support UAVs in addition to terrestrial users.

A channel environment at an altitude of <NUM>-feet may be different from a channel environment for a terrestrial user on the ground. For example, channel environment at high altitudes (e.g., higher than <NUM> feet) may experience a strong line of sight (LOS) component while the channel environment at lower altitudes (e.g. less than <NUM> feet) may experience multi-path characteristics, e.g., similar to a terrestrial WTRU experience. Mid-range altitudes (e.g., between <NUM> and <NUM> feet) may have LOS and multi-path characteristics. Channels may be modeled at different altitudes for terrestrial communication system adaptation.

Table <NUM> illustrates the number of base stations that may be detected by a drone. As seen in Table <NUM>, drones may detect more base stations as their altitude increases.

<FIG> is an example of simulation results for a single-cell scenario for different UAV altitudes. As can be seen in <FIG>, the coverage of the cell (e.g., measured power level) may increase as the altitude of the measurement is increased. Thus, as altitude increases, a given cell may be detected from farther away.

<FIG> is an example of simulation results for a multi-cell scenario based on a UAV altitude of <NUM>.

<FIG> show the Signal to Interference and Noise Ratio (SINR) and the received power for different UAV altitudes for single-cell and multiple-cell scenarios. A drone may observe interference in a downlink and/or may generate interference in an uplink. Higher interference levels may be detrimental to reliable command and control (C2) operation for drones, which may affect market adoption. A communication system may provide highly reliable C2 operation for drones and coexistence with terrestrial WTRUs.

A communication system, that provides for the coexistence of terrestrial WTRU's and drones, may experience interference, particularly inter-cell interference at higher altitudes when the cells are designed primarily to serve terrestrial WTRUs. Interference may limit drone communications, for example, due to the line of sight propagation environment drones may experiences and the impact drones may have on terrestrial WTRUs. Interference may be managed in 3GPP networks, e.g., using interference suppression and interference cancellation. Interference suppression may be implemented, for example, by applying linear filtering on a received signal. Interference cancellation may be implemented, for example, by explicitly cancelling interference. Desired information and interference information may be jointly detected. Partial information about an interferer (e.g., modulation and coding scheme (MCS) and or an interferers' channel) may be known. In an example of interference cancellation, an RNTI of an interferer may be available. Codeword cancellation may be performed, e.g., to improve performance.

Spectrum may be allocated for aerial WTRUs (e.g., unmanned aerial vehicles (UAVs), aerial WTRUs or drones may be used interchangeably herein) in C and L bands, e.g., C-band: <NUM>- <NUM> and L-band: <NUM> - <NUM>. Cellular operators may be provided part(s) of the C and L-bands where drones may be assigned dedicated resources. Reliable drone communications may be enabled in a cellular system framework, for example, by assigning dedicated resources (e.g., slices) to drones, which may meet FAA requirements for command & control.

<FIG> is an example of a drone under the coverage of multiple eNBs. In an example, of a cellular wireless system, a drone may be under coverage of multiple cells/eNBs (e.g., eNB-<NUM>/cell-<NUM>, eNB-<NUM>/cell-<NUM>, eNB-<NUM>/cell-<NUM>, etc.). An eNB (e.g., eNB-<NUM>) may be associated with one or more serving cells. A drone may experience downlink interference from its neighboring cells (e.g., eNB-<NUM>, eNB-<NUM>). The number of neighboring cells and the strength of interference from neighboring cells that a drone may experience, may be higher (e.g., much higher) than a terrestrial WTRU. A drone (e.g., unlike terrestrial WTRUs) may have line of sight propagation channels with neighboring cells due to a higher operational environment altitude. The high inter-cell interference that may be experienced by a drone may reduce its reliability, which may be extremely detrimental for command & control operations.

A WTRU may be configured to perform one or more actions to implement dynamic inter-cell interference management. For example, the WTRU may be configured to send and/or receive data in one or more data regions in an LTE-Pro framework that are specifically reserved for UAVs (and/or for a particular application such as command and control signaling). A data region-specific control channel search space (e.g., a UAV data region specific control channel search space) may be defined, for example, to decode interference information from neighboring cells. An interference decoding process may comprise, for example, a control channel decoding (e.g.. Physical Downlink Control Channel (PDCCH), enhanced PDCCH (ePDCCH), etc.) of a serving cell to infer a data region assignment, and an inter-cell control channel decoding (e.g.. Physical Downlink Control Channel (PDCCH), enhanced PDCCH (ePDCCH), etc.) to enable interference cancellation.

A WTRU may use the interference information to enable dynamic inter-cell interference management. The WTRU may be configured to implement interference cancellation in order to cancel LOS interference signals while ensuring efficient resource management (e.g., as compared to interference avoidance such as Enhanced Inter-Cell Interference Coordination (elCIC) which may limit scheduler flexibility and/or resource usage). Interference management may be performed by WTRUs using, for example, interference information provided by cooperating eNBs/cells. The interference information may be specific to one or more designated data regions.

<FIG> is an example of a designated data region in a PDSCH in an LTE subframe. <FIG> shows an example of providing designated data regions to enable unique requirements. For example, designated data regions (e.g., in an LTE-Pro framework) may enable dynamic inter-cell interference management for UAVs. This UAV framework may enable high reliability for command & control for a UAV in interference prone environments. As seen in <FIG>, a data region <NUM> may be dedicated for UAV data or command & control transmissions. A UAV may be scheduled for data in data region <NUM>. Another data region <NUM> may be used for other data transmission. For example, terrestrial WTRU's may be scheduled for data in data region <NUM>.

<FIG> is an example system view of dynamic interference management for UAV specific data regions. In an example (e.g., as shown in <FIG>), eNB <NUM>, eNB <NUM>, and eNB <NUM> may transmit during a given subframe. A UAV <NUM> may be in coverage of multiple eNBs (e.g., eNB <NUM>, eNB <NUM>, and eNB <NUM>) and/or multiple cells (e.g., some cells may be transmitted from the same transmission point such as the same eNB). In the example shown in <FIG>, the WTRU may be currently connected to a serving cell provided by eNB-<NUM>. The UAV may experience interference (e.g., interference <NUM> and <NUM>) from neighboring cells provided by eNB <NUM> and eNB <NUM>. Although not shown in <FIG>, the UAV <NUM> may also suffer from interference from another, non-serving cell transmitted by eNB <NUM> and/or from multiple neighbor cells from each of eNB <NUM> and/or eNB <NUM>.

A UAV may be scheduled for data transmission in a data region and/or a data zone. A data region (e.g., a UAV dedicated PDSCH <NUM>, <NUM>, and <NUM>) may include, for example, multiple data zones (e.g., zones <NUM>, <NUM>, <NUM>, and <NUM> in data regions <NUM>, <NUM>, <NUM>). In an example, there may be four UAV designated PDSCH data zones numbered <NUM>, <NUM>, <NUM> and <NUM>. Designated data regions and data zones may be pre-configured and may be uniform across cooperating eNBs (e.g., neighboring eNBs that may participate in data region/zone specific interference management). As seen in <FIG>, cooperating eNBs may be eNB <NUM>, eNB <NUM>, and eNB <NUM>. The cooperating eNBs may indicate interference information (e.g., interference information from a cell provided by the cooperating eNBs) for the date region and/or the date zone. Zones may (e.g., also) be distributed over PDSCH in a sub-frame. Zones may or may not be contiguous (e.g., as shown in <FIG>). A (e.g., each) zone may comprise a variable number of Physical Resource Blocks (PRBs). Zones may vary in size, and a plurality of zones may or may not be the same size. A network may schedule UAVs in one or more (e.g., any or all) UAV designated regions and/or zones. As seen in <FIG> a UAV <NUM> may be scheduled in data region <NUM> (e.g., when the serving eNB is eNB <NUM>) or data zone <NUM> of the data region <NUM>. For example, the scheduling information may be sent in a PDCCH and/or EPDCCH transmission. An eNB may service terrestrial WTRUs in zones designated for UAVs (e.g., zones unused by UAVs). UAVs may be scheduled on data zones outside designated zones. A (e.g., each) data zone may be allocated to multiple UAVs. A (e.g., each) UAV may be scheduled across multiple zones in the same Transmission Time Interval (TTI).

Dynamic interference cancellation may be provided, for example, for UAV designated regions such as data zones <NUM>-<NUM> shown in <FIG>.

A data zone/region specific control channel search space may be defined, for example, to enable inter-cell interference cancellation. An EPDCCH may have a data region specific search space defined per cell. A WTRU may use the region specific search space to determine (e.g., decode) interference information from neighboring cells. The WTRU may use the interference information from neighboring cells to perform interference cancelation. A data region specific search space may be frequency division multiplexed across cells, for example, to avoid interference on the EPDCCH. Regions <NUM>, <NUM>, and <NUM> in <FIG> may denote an EPDCCH data region specific search space. A data region specific search space may be, for example, localized within a physical resource block (PRB) pair (e.g., as shown by example in <FIG>), or distributed across several PRB pairs (e.g., as shown by example in <FIG>).

<FIG> is an example of data region specific EPDCCH search space distributed across several PRB pairs. As seen in <FIG>, search spaces (e.g., search space regions <NUM>, <NUM>, and <NUM>, which may be part of a distributed search space) may be distributed across PRB pairs. A WTRU may use the search spaces to determine interference information from a neighboring cell. The WTRU may use the interference information to perform interference cancelation.

In order to determine interference information for a given data region or data zone, a WTRU may be configured to utilize an interference decoding procedure whereby the interference information for a given cell/eNB within a given data region and/or zone may be provided in a control channel transmission from that given cell/eNB. Thus, a WTRU may decode data zone specific interference information from cooperating cells in order to cancel the interference from a data transmission that is sent in that data zone.

A UAV may infer data zones, which may be used to determine interference from neighboring cells. A UAV may determine a data region and/or zone where its scheduled data (e.g., data scheduled by an eNB) lies. For example, as seen in <FIG>, a UAV <NUM> may determine its data is scheduled in region <NUM>, or more specifically, in a particular zone (e.g., zone <NUM>) in the region <NUM>. A UAV may decode a PDCCH of a serving eNB to determine the data zone that is used for a data transmission. A UAV may perform a blind decoding of the PDCCH. A UAV may infer a resource block assignment, for example, upon successful PDCCH decoding. A UAV may (e.g., based on its resource block assignment) determine which one or more corresponding data zones the data is being transmitted in. The UAV may decode the corresponding data zone (e.g., the data zone which the UAV previously determined is being used for data transmission) of a neighboring cell to determine the interference caused by neighboring cells in the data zone.

A UAV may decode data zone specific interference information from cooperating neighbor cells. In an example, a UAV may perform blind decoding of a data zone specific EPDCCH to determine interference information from neighboring cells. A UAV may use, for example, a zone and/or region radio network temporary identifier (e.g., ZN-RNTI) and the (e.g. all the) aggregation levels that may be defined for the data zone and/or region (e.g., obtained by data zone inference) to decode a data zone and/or region specific EPDCCH of neighboring cells. As an example, the UAV may determine from a PDCCH in a serving cell that a PDSCH transmission is to be delivered to the UAV in data zone <NUM>. Data zone <NUM> may be associated with a zone specific RNTI (ZN-RNTI) and/or zone-specific search space. The UAV may attempt to decode one or more EPDCCH transmission in one or more neighbor cells using the ZN-RNTI in the zone specific search space. Upon successfully decoding an EPDCCH using die ZN-RNTI in the zone specific search space of a neighbor cell, the WTRU may determine interference information for the neighbor cell, which may be comprised in the EPDCCH transmission. The WTRU may use this interference information to attempt to cancel the interference caused by the neighbor cell from the PDSCH transmission sent in the data zone from the serving cell. The process may be repeated for multiple neighbor cells.

Interference information for a (e.g., each) zone may be encoded, for example, by cooperating eNBs. A (e.g., every) cooperating eNB may encode interference information of (e.g., all) zones in its EPDCCH (e.g., for use by UAVs connected to neighboring cells). An eNB may (e.g., also) encode its own PDSCH information in a PDCCH.

A data zone specific control channel search may be provided. An RNTI may be defined per data zone (ZN-RNTI) and/or per region. A cyclic redundancy check (CRC) of the EPDCCH payload bits may be scrambled with the ZN-RNTI. In an example (e.g., as shown in <FIG> and <FIG>), there may be four defined ZN-RNTIs, e.g., one for each of zone-<NUM>, zone-<NUM>, zone-<NUM> and zone-<NUM>. Interference information for a zone may be contained in the EPDCCH payload bits for that zone. Zone RNTI's (e.g., for every zone) may be common to the (e.g., all the) cooperating cells that may participate in UAV interference management. In some example, the RNTI may be common across the zones (e.g., may be region specific instead). For example, the indication of which zone the interference information is applicable to may be indicated in the DCI and/or the ZN-RNTI may be common across each of the zones in the region.

<FIG> is an example of encoding zone specific interference information in an EPDCCH. In an example of interference encoding, a <NUM>-bit CRC may be attached to EPDCCH payload bits. The EPDCCH payload bits may carry the interference information of a data zone and/or data region. CRC bits may be scrambled, for example, using a zone or region RNTI (e.g., ZN-RNTI). EPDCCH payload bits and scrambled CRC bits may be channel encoded (e.g., at rate <MAT>), rate matched (e.g., similar to PDCCH) and transmitted. This procedure may be repeated for each zone, for example, by using the appropriate zone RNTIs.

An eNB may use radio resource control (RRC) signaling for decoding interference information. For example, an eNB may provide an appropriate zone RNTI(s) in which a UAV's PDSCH may be scheduled, or all zone RNTIs available for data transmission to a UAV. An eNB may (e.g., also) signal an aggregation level of zone(s), for example, so that a UAV does not have to perform blind decoding.

Interference dependent aggregation levels may be provided by an eNB. Aggregation levels (e.g., during EPDCCH encoding) may be dependent on an interference level of a zone. A higher aggregation level may be used for data zones creating more interference.

An aggregation level of a zone may be adapted, for example, when an eNB may have scheduled one or more users (e.g., many users with different MCS levels) in a data zone. An aggregation level of a zone may be adapted, for example, to enable robustness in providing interference information to users of neighboring cells. An eNB may adapt a coding rate, for example, to ensure users of neighboring cells are able to decode interference information with a very high probability. An eNB may seek to ensure users in neighboring cells are not affected, for example, when die eNB allocates higher powers in some sets of PRBs/zones, which may increase interference.

The bandwidth that is available for search space may be constrained. For example, the highest aggregation levels may not be available in all data zones. There may be a fixed number of control channel elements (CCEs), which may be shared by all the aggregation levels.

Blocking may be minimized while maximizing the use of a desired aggregation level for each zone. A desired aggregation level for each zone may not be possible in some circumstances, e.g., due to a constrained bandwidth. Blocking of a desired aggregation level for a zone may be minimized. Sufficient randomization in enhanced CCEs (ECCEs) may be used for a data zone in a (e.g. each) sub-frame, for example, to minimize blocking. A search space may be dependent on, for example, a data zone, sub-frame and/or an aggregation level.

<FIG> is an example configuration of ECCEs shared by zones. <FIG> shows an example of zone based aggregation levels. Table <NUM> shows example search candidate configurations for different aggregation levels. In an example, there may be <NUM> ECCEs shared by the (e.g., all the) zones and there may be three different aggregation levels.

In an example (e.g., as shown by dashed line in <FIG>), zone-<NUM> may occupy ECCEs <NUM>-<NUM> at aggregation level-<NUM>. Other zones may be prevented from using aggregation level-<NUM> and/or aggregation level-<NUM>, for example, with ECCEs <NUM>-<NUM> defined for level-<NUM> and/or level-<NUM> aggregation being allocated. Sufficient randomization dependent on aggregation level, data zone, and subframe number may be implemented by an eNB, for example, to minimize this effect, e.g., when calculated over several subframes.

In an example, a data zone specific search space at aggregation level L, and at sub-frame k may be given by Eq. (<NUM>): <MAT> where Y<NUM> may be zone RNTI, m' = <NUM>,<NUM>,<NUM>. (# of ePDCCH candidates - <NUM>), i = <NUM>,<NUM>,<NUM>. L - <NUM>, and D may be a constant.

An adjustable bandwidth search space may be provided by eNBs, for example, to use (e.g., efficiently use) EPDCCH search space resources. An aggregation level may be provided for a given zone. A total search space bandwidth may be allocated, for example, so that a maximum allowed aggregation level may be provisioned for one or more zones. ECCEs may be defined in a localized/contiguous manner such that that an eNB may use the unused ECCEs of an EPDCCH PRB pair for a PDSCH transmission If ECCEs are defined in such a manner and a maximum aggregation level is not required for all zones, search spaces EPDCCH resources may not be wasted. This scheme may provide desired (e.g., fully utilized) aggregation levels for a zone (e.g., each zone), and may ensure that unused EPDCCH search space are utilized for PDSCH transmissions.

In an example (e.g., as shown in <FIG>) EPDCCH may be defined in two PRB pairs. If one PRB pair is used for EPDCCH search space (e.g., EPDCCH <NUM>, <NUM>, and <NUM>), the other PRB pair (e.g., EPDCCH <NUM>, <NUM>, and <NUM>) may be used for PDSCH. EPDCCH search space encoding, which may include defining ECCEs, may be performed in a localized/contiguous manner (e.g., in a PRB pair-wise fashion). In an example, ECCEs that are defined for a first EPDCCH search space (e.g., EPDCCH PRB pair) may be encoded/searched. This may be followed by a next EPDCCH search space (e.g., a next EPDCCH PRB pair) and may continue, for example, until no EPDCCH search spaces remain.

An eNB may provide interference assistance signaling in EPDCCH. The interference signaling may include signaling interference data in a zone specific search space. Bandwidth limitations may constrain the amount of interference information that can be signaled. Examples may be provided herein to overcome bandwidth limitations.

Partial interference cancellation may be implemented using, for example, interference assistance signaling. In an example, (e.g., only) Modulation and Coding Scheme (MCS) information and corresponding PRB allocations may be provided (e.g., for interference assistance signaling) by an eNB. A UAV may be informed or may determine which zones/PRBs its data may be scheduled for by a serving eNB. A UAV may decode the corresponding zone interference information, which may be included in the EPDCCH of neighboring cells. The corresponding zone interference information may allow a UAV to determine an MCS that may be used for its PRBs. An estimate of interference may be obtained using zone interference information (e.g., MCS information and/or corresponding PRB allocation for neighboring cells), for example, when actual interference data is not signaled.

<FIG> is an example of zone based interference assistance signaling for partial interference cancellation, which may be provided by cooperating eNBs. <FIG> shows an example of zone based interference signaling, for example, for the data zone structure shown in <FIG> and <FIG>. Interference information signaling may indicate the PRB allocations and the corresponding MCS that may be used by an eNB in a zone.

Complete interference cancellation may be provided using, for example, a Cell Radio Network Temporary Identifier (C-RNTI). A C-RNTI may be provided in the EPDCCH of a neighboring cell for a WTRU that may be scheduled in a zone.

<FIG> is an example of EPDCCH encoding for complete interference cancellation. In an example of encoding and decoding, an eNB may encode a C-RNTI of a user that may be scheduled in a data zone. The C-RNTI of the user may be attached to CRC bits (e.g., <NUM> bit CRC bits) and scrambled with a zone or region RNTI (e.g., ZN-RNTI). An eNB may transmit the encoded C-RNTI in an EPDCCH.

A WTRU may perform a blind decoding of the EPDCCH of a neighboring cell, for example, to decode a C-RNTI of the user in the neighboring cell that is scheduled in the data zone. The user may use the C-RNTI to obtain interference information corresponding to the data zone of interest from the neighboring cell. In some scenarios, a C-RNTI specific to the user may be used to decode the interference information in the neighbor cell. In some scenario, a ZN-RNTI may be used to decode the interference information in the neighbor cell. In some scenarios, both a C-RNTI and a ZN-RNTI may be used to decode the interference information in the neighbor cell.

A serving cell user may use an obtained C-RNTIto decode a PDCCH of a neighboring cell. MCS information etc., which may help perform partial interference cancellation, may be obtained, for example, based on the decoding of the PDCCH of a neighboring cell.

A PDSCH of a neighboring cell may be decoded, for example, to perform code word level (e.g., successive) interference cancellation (e.g., perfect interference cancellation).

Data zone specific reference signals (DS-RS) may enable UAVs connected to neighboring cells, for example, to estimate an interference channel on a per zone basis. Interference channel estimation using a cell specific reference signals (CRS) may not be performed on a per-zone basis. A channel estimation that may be obtained by a CRS (e.g., over a much wider band than a data zone(s)/region) may not reflect an interference channel per zone. A cell specific reference sequence, which may be present (e.g., irrespective of cell bandwidth), may not be present in a zone(s)/region of interest for zone based channel estimation.

<FIG> is an example of a DS-RS, which may be used for interference channel estimation. <FIG> shows an example where DS-RS may be placed on a per zone basis. In an example, cooperating eNBs may have a cooperating cell-id, which may be a part of reference signal sent by cooperating eNBs. For example, a reference sequence identifier (ID) for zone-x sent by a cooperating eNB id-y may be the tuple (y, x).

Cooperating eNB reference sequence IDs may be provided, for example, by a serving eNB to a UAV (e.g., through RRC). A UAV may report the CRS of neighboring cells to a serving eNB. Cooperating eNBs may coordinate, amongst themselves (e.g., through X2), to generate reference sequence IDs that may be suitable for interference channel estimation. A serving cell may provide a UAV with the reference sequence IDs for interference channel estimation.

Cooperating eNBs may determine (e.g., agree on) a frequency shift (e.g., using the X2 interface) where DS-RS may be present. A serving eNB may indicate the frequency shift to a UAV.

Zone specific sequences used by eNBs may be orthogonal. The eNBs may use the same resource blocks to transmit an orthogonal reference signal on a per zone basis. In an example, cooperating eNBs may use the same resource blocks (e.g., as shown in zones in <FIG>) to transmit orthogonal sequences, for example, so a UAV may concurrently measure an interference channel from cooperating eNBs (e.g., all cooperating eNBs). An orthogonal sequence that may be used by cooperating eNBs may be signaled by a serving eNB to a UAV, for example, to permit the UAV to estimate interference channel to an appropriate eNB.

A connection to a channel state information reference signal (CSI-RS) may be provided. A DS-RS may be transmitted specific to zone(s). A CSI-RS may be transmitted in multiple (e.g., all) resource blocks in a selected sub-frame (e.g., covering entire cell bandwidth). A DS-RS may re-use a CSI-RS structure for a reference signal and its placements, for example, as shown in <FIG>.

<FIG> is an example of DS-RS placements for interference channel estimation. As seen in <FIG>, DS-RS placements are marked with letters while DM-RS/CRS placements are marked by shaded and hashed regions. In an example, DS-RS may be placed anywhere in a region marked with letters (e.g., Ax,. In an example, a cell may place a DS-RS for zone-<NUM> in a region marked "Ax," place a DS-RS for zone-<NUM> in the region marked "Qx" and so on.

A DS-RS may be transmitted (e.g., only) in sub-frames unused by a CSI-RS. A DS-RS may (e.g., similar to CSI-RS) have one or more of the following attributes: periodicity and/or a sub-frame offset.

In an example, a CSI-RS/sub-frame offset may be configured, for example, so that channel parameters may be measured less often (e.g., higher sub-frame offset/periodicity), e.g., for older and newer release WTRUs. Newer release WTRUs (e.g., UAV category WTRUs) may be configured with a DS-RS having lower sub-frame offsets/periodicity than a CSI-RS. A DS-RS scheme may enable an interference channel to be measured more often without transmitting over an entire bandwidth, which may improve spectral efficiency, e.g., relative to a CSI-RS.

One or more (e.g., all) eNBs may place a DS-RS reference signal (e.g. only) in zones where data may be scheduled. A DS-RS need not be placed on all zones on all sub-frames. Zones in which a DS-RS may be placed may be signaled through RRC, for example.

Interference management may be provided on a superzone basis. Foregoing examples may be similarly applied to regions (e.g., superzones). Foregoing examples may be read, for example, by substituting a region or multiple (e.g., many) zones (e.g., a superzone) for a zone. Encoding for a superzone may be simpler than for a zone, but may provide less granularity.

<FIG> is an example of superzone (e.g., region) interference management. In an example, there may be one RNTI for an entire UAV dedicated PDSCH (e.g., as shown by <NUM> in <FIG>). Several aggregation levels may be used (e.g. similar to previous examples) for the UAV dedicated PDSCH. A UAV may perform blind decoding for allowable aggregation levels using a (e.g. only one) zone and/or region RNTI (e.g., ZN-RNTI).

The reliability of PDCCH may be enhanced, for example, by using an EPDCCH. EPDCCH may be frequency division multiplexed across cells. If an EPDDCH is frequency division multiplexed across cells, EPDCCH interference may not exist between serving and neighboring cells. EPDCCH may have a higher probability of reliable decoding (e.g., decoding by the WTRUs being served by neighboring cells/eNBs). A PDCCH may face interference with neighboring cells, for example, when serving and neighboring cell PDCCHs may not be orthogonal. There may (e.g., also) be significant interference from neighboring cells, for example, due to line of sight channels.

Additional information useful for decoding PDCCH may be placed in an EPDCCH, for example, when a UAV may be aware of its data zone through side information (e.g., service based). A UAV may decode an EPDCCH, for example, using an appropriate zone RNTI, which may be data zone aware. An example is shown in <FIG> is an example of data zone aware PDCCH/EPDCCH decoding. Joint encoding of PDCCH/EPDCC may be implemented, for example, so that PDCCH may be decoded by itself. Additional parity bits of PDCCH (e.g., turbo coded bits) may be provided in EPDCCH, for example, along with a C-RNTI for a user. A CRC of an EPDCCH may be scrambled by a zone RNTI, channel encoded, rate matched and transmitted in EPDCCH.

A user (e.g., a serving cell user) may use a ZN-RNTI (e.g., as the user may be data zone aware) to decode a serving cell EPDCCH (e.g., its own cell EPDCCH). A user may obtain additional parity bits of a PDCCH, e.g., as a payload available in EPDCCH. A user may use the additional parity bits, for example, to decode the PDCCH (e.g., when PDCCH decoding has failed).

A user (e.g., a neighboring cell user) may decode an EPDCCH of a neighboring cell, for example, using a ZN-RNTI, to obtain a C-RNTI and additional parity bits of its neighboring cell PDCCH. A user may be zone aware. A ZN-RNTI may be common to all cooperating eNBs, which may allow for users of cooperating cells to decode the EPDCCH of other cooperating cells. A user may use the additional parity bits and the C-RNTI of the neighboring cell user, for example, to decode the neighboring cell PDCCH. A serving cell user may (e.g., by decoding the PDCCH of the neighboring cell) infer MCS information to perform partial interference cancellation. A serving cell user may (e.g., alternatively) also decode a PDSCH of a neighboring cell, for example, to perform perfect code word interference cancellation.

Interference management may be provided during semi-persistent scheduling (SPS) transmissions. Resource indication details may be provided (e.g., by an eNB) in a PDCCH (e.g., only) at the beginning of an SPS transmission. A PDCCH, which may be related to dynamically scheduled transmissions, may be used to change the resource assignments for an existing SPS transmission or for one or more retransmissions. A UAV may monitor the PDCCH during SPS transmission.

<FIG> is an example of interference management during SPS. As seen in <FIG>, when a SPS is scheduled (e.g., first scheduled), the corresponding resource information may be provided in PDCCH. Resource information may not be provided in PDCCH for subsequent SPS transmissions. Interference information may be provided to users in neighboring cells (e.g. in this situation).

As seen in <FIG>, when a neighboring cell continues an SPS transmission (e.g., when PDCCH signaling on the resource information is not performed), the interference information for a zone (e.g., for all zones) may be transmitted (e.g., may still be transmitted) in the subframe.

An eNB may (e.g., when performing an SPS transmission) provide (e.g., via an X2 interface), for example, an MCS, resource assignment information for one or more (e.g., all) zones, and an SPS period to cooperating eNBs/neighboring cells. A serving cell may (e.g., may in turn) signal interference information of zones obtained from (e.g., all) neighboring cells (e.g., through RRC/media access control (MAC) control element (CE) signaling) to UAVs. The serving cell may signal (e.g., may also, additionally, or alternatively signal) subframe number(s)/periodicity, for which signaled interference information may be valid.

Uplink interference management may be providedby eNBs/cells. For example, a dedicated data region/zone may be extended to uplink transmissions. An eNB may determine MCS and PRB allocations for its users in an uplink. An eNB may (e.g., also) transmit uplink interference information to neighboring cells.

An eNB may signal, to cooperating eNBs (e.g., via X2), MCS and PRB allocation information for (e.g., every) zone(s)/region (e.g., interference information for all zones), for example, similar to examples discussed with respect to <FIG>.

An (e.g., each) eNB may decode a PDCCH of a neighboring cell, e.g., to obtain uplink interference information. A C-RNTI of users may be signaled among cooperating eNBs (e.g., through X2). eNBs may, for example, support full-duplex transmission, e.g., to transmit their own PDCCH in addition to decoding a neighboring cell's PDCCHs.

A downlink control information (DCI) format may be provided for UAVs. MCS and PRB assignments may be provided in an EPDCCH, for example, to signal interference information to neighboring cells. This information may (e.g., may also) be in a PDCCH that may be signaled by a eNB to a UAV/WTRU. A UAV that may be connected to a serving cell may obtain it, for example, from a PDCCH or a EPDCCH. MCS and PRB allocations may be provided in PDCCH on a per-user basis by an eNB/cell. MCS and PRB allocations may be provided (e.g., instead provided) on aper-zone basis.

MCS information may be transmitted (e.g., only) in an EPDCCH, for example, for UAV category WTRUs. A DCI for format-<NUM> may, for example, have one or more of the following: a resource allocation header, resource block assignment for resource allocation (RA) type <NUM>, subset, shift, resource block assignment for block type-<NUM>, Hybrid Automatic Repeat Request (HARQ) process, redundancy version (RV) and/or Transmit Power Control (TPC) for PUCCH. In an example, a DCI may not include MCS information in a PDCCH, because this information may be available (e.g., may already be available) in EPDCCH.

A UAV type WTRU may obtain PRB allocations from PDCCH and may decode an appropriate zone in an EPDCCH, for example, to obtain MCS information, for example, according to a signaling example described with respect to <FIG>.

Systems, methods, and instrumentalities have been disclosed for active interference management. Active interference management may be provided for designated data regions and/or superzones. VAV-specific or other designated data regions (e.g., with data zones) may enable dynamic inter-cell interference management and high reliability command & control for UAVs in interference prone environments. Data zone/region specific control channel search space may support inter-cell interference cancellation. Aggregation levels (e.g., during EPDCCH encoding) may be dependent on an interference level of a zone. Data zone specific reference signals (DS-RS) may enable UAVs connected to neighboring cells to estimate an interference channel per zone. Interference management may be provided during semi-persistent scheduling (SPS) transmissions. Reliability of Physical Downlink Control Channel (PDCCH) may be enhanced (EPDCCH), e.g., with interference assistance signaling. Uplink interference management may operate with dedicated data region/zones. A downlink control information (DCI) format may be provided for UAVs where the MCS, PRB allocations are signaled in EPCCH. Other parameters (the rest of the parameters like TPC, HARQ process, RV, etc.) may be signaled in PDCCH.

Features, elements and actions (e.g., processes and instrumentalities) are described by way of non-limiting examples. While examples may be directed to LTE, LTE-A, New Radio (NR) or <NUM> protocols, subject matter herein is applicable to other wireless communications, systems, services and protocols. Each feature, element, action or other aspect of the described subject matter, whether presented in figures or description, may be implemented alone or in any combination, including with other subject matter, whether known or unknown, in any order, regardless of examples presented herein.

The processes and instrumentalities described herein may apply in any combination, may apply to other wireless technologies, and for other services.

A WTRU may refer to an identity of the physical device, or to the user's identity such as subscription related identities, e.g., MSISDN, SIP URI, etc. WTRU may refer to application-based identities, e.g., user names that may be used per application.

Data region specific control channel search space(s) may be defined per cell. For example, <FIG> illustrates an example where multiple (e.g., two) data regions are defined in PDSCH: a UAV dedicated PDSCH region and other application specific PDSCH region. The corresponding control channel specific search spaces for each PDSCH region, <NUM> and <NUM>, are shown in a contiguous fashion in <FIG>. <FIG> illustrates an example of data specific control channel search space(s) that are defined in a distributed manner. As seen in <FIG>, UAV specific control channel search spaces <NUM>, <NUM>, and <NUM> and other application control channel search spaces <NUM>, <NUM>, and <NUM> are distributed. Depending on the application, the WTRU may perform a control channel search in the appropriate search space without having to perform a search in other search spaces. For example, UAV may use the control search space defined for UAVs and may determine not to use other search space regions, thereby reducing complexity in performing search space operations. It should be noted the data specific control channel search space definition is not limited only to EPDCCH/PDCCH and may be applicable to other types of control channels.

Claim 1:
A method for performing interference cancelation comprising:
receiving a physical downlink control channel, PDCCH, transmission,
wherein the PDCCH transmission is received via a serving cell;
decoding downlink control information, DCI, comprised in the PDCCH
transmission;
determining a data region associated with a downlink transmission in the serving cell, wherein the determination is based on the decoded DCI;
receiving one or more enhanced physical downlink control channel, EPDCCH, transmissions via one or more neighbor cells;
decoding the one or more EPDCCH transmissions using a zone specific identifier, wherein the one or more decoded EPDCCH transmissions comprise interference information associated with the data region; and
decoding the downlink transmission associated with the data region using the interference information comprised in the one or more decoded EPDCCH transmissions.