Patent Description:
This disclosure relates generally to wireless communication, and more specifically, to techniques for switching between full duplex and half duplex in millimeter-wave nodes.

Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems (e.g., Long Term Evolution (LTE) or New Radio (NR)). A wireless multiple-access communication system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).

<CIT> relates to a time division duplex (TDD) communication system, an unconnected base station that is not directly connected to a core network which transmits uplink backhaul signals to a connected base station when the unconnected base station is transmitting downlink signals to one or more user equipment (UE) devices and receives downlink backhaul signals from the connected base station when receiving uplink signals from one or more UE devices. After determining the transmission schedule of the connected base station, the unconnected base station selects a transmission schedule that is orthogonal to the connected base station transmission schedule. Depending on the particular implementation, the unconnected base station may be a repeater base station, a relay base station, or a self-backhauled base station.

<CIT> relates to a method for performing beamformed backhaul communications that includes determining first formats of subframes supporting access communications between the first TRP and user equipments (UEs) served by the first TRP, determining a subset of the subframes supporting access communications, the subset of the subframes supports backhaul communications between the first TRP and a second TRP, and communicating with a UE over an access link in accordance with the subset of subframes.

<NPL> discloses that it has been agreed to specify measurement and reporting of L1-SINR in Rel-<NUM> at least targeting FR2 operation and dedicated ZP IMR and NZP IMR can be configured for interference measurement for SINR.

<NPL> relates to mapping between CMR and NZP IMR and discloses that for L1-SINR reporting, one-to-one mapping between CMR and NZP IMR will occur large signalling/resource overhead for gNB to acquire accurate knowledge on interference situation. <NUM> CMR can be mapped to <NUM> or more than <NUM> IMRs.

The aspects of the present invention are defined by the appended independent claims.

A method, an apparatus and a computer program comprising code are provided for switching between full duplex and half duplex in wireless nodes. A wireless node may measure self-interference for one or more transmitter-receiver beam pairs. Based on the self-interference measurements, the wireless node may communicate on a transmitter-receiver beam pair in full duplex or half duplex. A duplex mode may be determined based on self-interference, as well as, optionally with other additional metrics such as rate and latency. A wireless node may switch between full duplex and half duplex based on the duplex mode determination. In addition, suitable beam pairs may be selected, along with associated duplex modes.

According to claim <NUM>, a method of wireless communication is provided. The method may be performed by a wireless node or component(s) thereof. A metric of self-interference for a beam pair may be measured, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at the wireless node. Furthermore, the wireless node may communicate on the beam pair in full duplex or half duplex based on the metric.

A wireless node, not claimed at present, may be also provided. The wireless node may include a memory and a processor coupled with the memory. The processor may be configured to measure a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at the wireless node. The processor may be further configured to communicate, on the beam pair, in full duplex or half duplex based on the metric.

According to independent claim <NUM>, an apparatus of wireless communication is provided. The apparatus may include means for measuring a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at a wireless node. The apparatus may also include means for communicating, on the beam pair, in full duplex or half duplex based on the metric.

According to independent claim <NUM>, a non-transitory computer-readable medium having instructions stored thereon is provided. The instructions may include codes executable for a wireless node to perform measuring a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at the wireless node. The instructions may also include codes for communicating, on the beam pair, in full duplex or half duplex based on the metric.

From various aspects, an amount of interference from the TX beam to the RX beam of a beam pair may be measured. The metric of self-interference may include at least one of signal-to-interference-and-noise ratio (SINR), reference signal received power (RSRP), reference signal received quality (RSRQ), or signal-to-interference ratio (SIR).

From various aspects, the metric may be reported to a network entity for duplex mode determination. The network entity may be a central unit connected to one or more distributed wireless nodes.

From various aspects, a duplex mode for a beam pair may be determined based on the metric. According to an aspect, the beam pair may be selected over a different beam pair for full duplex based on the beam pair having lower self-interference. According to another aspect, the duplex mode may be determined based on a rate comparison between full duplex and half duplex for the beam pair.

From various aspects, the duplex mode may be determined further based on a latency constraint. According to an aspect, the beam pair with its associated duplex mode may be selected over a different beam pair based on the beam pair having a higher rate.

Various features and advantages of this disclosure are described in further details below. Other features will be apparent from the description, drawings, and/or the claims.

Illustrative and non-limiting drawings are provided to aid in the description of various aspects and implementations. Unless specified otherwise, like reference symbols indicate like elements.

Communication on millimeter wave (mmWave) or Frequency Range <NUM> (FR2) is an important part of the fifth-generation (<NUM>) NR systems and standards. Almost all current system designs are focused on half duplex (HD) in which wireless nodes alternate between transmission and reception in time. Though offering simpler implementation solutions, half duplex may not fully utilize the communication resources. In contrast, full duplex (FD) allows simultaneous transmission and reception at the same time, even at the same frequency in some cases, which may significantly increase performance over half duplex.

Full duplex systems nevertheless may behave differently from half duplex systems and entail different performance-cost tradeoffs. Simultaneous transmission and reception can result in increased rate and spectral efficiency, but the performance may be impacted by an enhanced self-interference from transmission part of the system to reception part of the system, e.g., as caused by clutters in the wave propagation environment. To mitigate self-interference, more complex circuitry for transmitter-receiver isolation may be used. Thus, the potential full duplex gain may be set off against negative impact of self-interference and other considerations (such as implementation cost and complexity). In some scenarios where FD performance gain can outweigh cost, full duplex may outperform half duplex, whereas the reverse may be true in other scenarios.

Since conditions favoring one duplex mode over the other may change, a holistic approach based on self-measurements may optimize system performance by dynamically selecting beams and/or switching between full duplex and half duplex on the beams depending on performance criteria and measurement metrics. For example, appropriate (perhaps different) wireless nodes for transmitter and receiver may be selected with corresponding beams/directions chosen to avoid self-interference. Generally speaking, a dense deployment of wireless nodes, with potential network coordination, may be more conductive to dynamic beam selection and duplex mode determination, because of sufficiently rich scattering around wireless nodes, availability of a good set of neighbor nodes, and/or strong coordination in neighbor node selection. However, not all deployments may be as favorable as described above; for example, only some strong directions may exist from a node to other nodes, only some viable neighbor nodes exist to establish links, or neighbor nodes can only be reached by beams or directions for which self-interference may not be avoided. Thus, in case when conditions may indicate that full duplex operation could be problematic, falling back to half duplex can achieve a more robust system performance.

Aspects of the disclosure introduced above are described below in the context of a wireless communication system. Illustrative and non-limiting examples of designs and techniques supporting switching between full duplex and half duplex for millimeter-wave communications are then described. Aspects of the disclosure are illustrated by and described with reference to various apparatus diagrams, system diagrams, and flowcharts.

<FIG> illustrates an example of a wireless communication system <NUM> in accordance with the present disclosure. The wireless communication system <NUM> generally include user devices (e.g., UEs <NUM>) and network devices (e.g., base stations <NUM> and entities of a core network <NUM>). Examples of the wireless communication system <NUM> may include various wireless network technologies, such as LTE or NR, as developed and standardized by the Third Generation Partnership Project (3GPP).

A user equipment generally refers to a device (e.g., of an end-user) that utilizes wireless communication service provided by a wireless communication network. As illustrated, a UE <NUM> may take a variety of forms, such as a cellphone, a computation device, a machine-type-communication (MTC) or Internet-of-Things (IoT) device, or a vehicular device, and so on. UEs <NUM> may be dispersed throughout the wireless communication system <NUM>, and each UE <NUM> may be stationary or mobile. As used herein, a "user equipment" may also be referred to as a subscriber station, an access terminal, a remote terminal, a handset, a user device, a customer premises equipment, or generally a wireless communication device or some other suitable terminology in the context.

A base station generally refers to a network device that communicates wirelessly (e.g., via over-the-air radio channel) with user devices. Base stations <NUM> may communicate with one another and/or with the core network <NUM>, e.g., through backhaul links or other network nodes. Base stations <NUM> often serve as entry points for a user equipment to access communication services provided by a wireless communication network. Base stations <NUM> (and in some examples, with other entities) may constitute a radio access network (RAN), which connects UEs <NUM> to the core network <NUM> via certain radio access technology (RAT), such as LTE or NR. In 3GPP context, a base station may be known as an evolved Node B (eNB) for LTE or a next generation Node B (gNB) for NR. But generally, as used herein, a "base station" may also be referred to as a base transceiver station, a radio base station, an access point, or some other suitable terminology in the context.

In general, a base station <NUM> may communicate with a UE <NUM> using communication resources in time, frequency, and/or space. Communication may occur in two directions: "downlink" (or "forward link") from the base station <NUM> to the UE <NUM>; or in reverse, "uplink" (or "reverse link") from the UE <NUM> to the base station <NUM>. Downlink and uplink transmissions may take place on same or different frequency bands and during same or different time instances. In terms of time resources, time intervals of transmission may be organized according to a "frame" structure. A frame may further be divided into a number of subframes or slots, each further containing a number of symbols, and so on. In terms of frequency resources, a variety of frequency bands (e.g., ranging from ultra-high frequency to extremely-high frequency) may be used. The frequency bands may be "licensed" (e.g., to an operator exclusively), or "unlicensed" (or "shared") (e.g., shared by general users subject to interference and coexistence regulation). On a frequency band, a "carrier" may generally refer to a set of radio frequency spectrum resources supporting uplink and/or downlink communication, such as transmission of physical signals or channels. In some examples a carrier may be made up of multiple sub-carriers (e.g., waveform signals of multiple different frequencies). In terms of spatial resources, base stations <NUM> and/or UEs <NUM> may communicate on one or more (physical or virtual) antenna ports, for example, based on various single-user or multi-user, Multiple-Input and Multiple Output (MIMO) techniques, such as spatial diversity, multiplexing, or beamforming, and so on. Multiple antennas may be co-located or distributed in diverse geographic locations.

A base station <NUM> may operate one or more "cells" <NUM>. The term "cell" generally refers to a logical entity used for communication with a base station (e.g., over one or more carriers), and in some context, may also refer to a portion of a geographic coverage area (e.g., a sector) over which the logical entity operates. An identifier (e.g., a cell identity) may be associated with a cell to distinguish the cell from another cell. A UE <NUM> may register and communicate with one or more cells <NUM> (e.g., serving cells) while monitoring other cells <NUM> (e.g., neighbor cells).

The core network <NUM> may include a network of entities providing user authentication, voice/multimedia communications, Internet Protocol (IP) connectivity, and/or other application services. These entities may be referred to as nodes, servers, gateways, functions, or other suitable terminologies. Examples of the core network <NUM> may include an evolved packet core (EPC) in a LTE network, a <NUM> Core (5GC) in a <NUM> or NR network, or generally, other packet based network architecture. The core network <NUM>, such as in 5GC, may separate user plane function from control plane function into different entities. The user plane generally handles transfer of user data, whereas the control plane exchange of network control information. A base station <NUM> in a radio access network may communicate with an entity <NUM> to access services of the core network <NUM>. The entity <NUM> may incorporate a mobility management entity (MME) and/or a serving gateway (SGW), as in EPC, to implement control plane and/or user plane protocols. In other examples, the entity <NUM> may represent separate control plane or user plane functions, such as a core access and mobility management function (AMF) and/or a user plane function (UPF) in 5GC. The MME or AMF may provide control plane functionalities such as mobility, authentication, and/or bearer management for UEs <NUM> served by the base station <NUM>. User data may be routed by the entity <NUM> through another entity <NUM>, such as a PDN gateway (PGW) of EPC or a UPF of 5GC, connected to a packet data network (PDN) <NUM>. The entity <NUM> may transport IP packets between the PDN <NUM> and a UE <NUM> accessing the PDN <NUM> via a base station <NUM> and the core network <NUM>. The entity <NUM> may also provide IP address allocation as well as other functions. The core network <NUM> may also include other entities. For example, subscriber information or user profile may be stored in a server <NUM>, such as a home subscriber server (HSS), which may be queried, e.g., for user authentication, registration, or billing, etc..

In general, a packet data network may be any packet (e.g., IP) based network. A UE <NUM> may communicate with the PDN <NUM> for a variety of applications or services. Examples of the PDN <NUM> may include an operator's service network, an IP Multimedia Subsystem (IMS), or generally the Internet. The IMS may provide voice, video, or other multimedia applications, such as voice over IP (VoIP) call, across various types of communication networks.

The wireless communication system <NUM> may represent a packet-based network that operates according to various layered protocol stacks. Multiple protocol layers (or sublayers) may reside in a UE <NUM>, a base station <NUM>, and an entity of a core network <NUM>. For example, in the user plane, a Packet Data Convergence Protocol (PDCP) layer, with counterparts residing in a UE <NUM> and a base station <NUM>, may provide wireless communication service for user data via data radio bearers (DRBs). Below PDCP may sit a Radio Link Control (RLC) layer, followed by a Medium Access Control (MAC) layer, and lastly by a Physical (PHY) layer, with counterparts residing in the UE <NUM> and the base station <NUM>. In some examples (such as in NR), a Service Data Adaptation Protocol (SDAP) layer may be interfaced between an upper protocol stack (e.g., IP) and the PDCP, for example, to handle mapping between quality of service (QoS) flows and data radio bearers. The SDAP, PDCP, RLC, and MAC layer may correspond to sublayers of "Layer <NUM>" (or Data Link Layer) in terms of Open Systems Interconnection (OSI) model, and the PHY layer the "Layer <NUM>" (or Physical Layer). The SDAP layer may map between a QoS flow and a data radio bearer (DRB) and may also perform other QoS related operations. The PDCP layer may handle transfer of user data, header compression, in-sequence delivery, duplication detection, etc. The RLC layer may perform transfer of upper layer PDUs according to transmission modes, error correction through automatic repeat request (ARQ), segmentation/concatenation, etc. The MAC layer may handle multiplexing of logical channels into transport channels and may schedule uplink/downlink transmission or reception at the PHY layer. The MAC may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. The PHY layer may transmit information from MAC transport channels over the air interface. The PHY layer may also handle various aspects of power control, link adaptation, cell search, etc..

In the control plane, at a UE <NUM>, an Non-Access Stratum (NAS) layer may lie on top of a Radio Resource Control (RRC) layer. The NAS layer may handle connection or session management between the UE <NUM> and a core network <NUM>, whereas the RRC layer may handle radio resource management between the UE <NUM> and a base station <NUM>. The RRC layer may correspond to "Layer <NUM>" (or Network Layer) in the OSI model. The RRC layer may perform RRC connection management (including establishment, configuration, maintenance, and/or release) between the UE <NUM> and the base station <NUM>, data and signaling radio bearer management, system information broadcast, mobility management, etc. In addition, the RRC layer may encapsulate and pass NAS messages between the UE <NUM> and the core network <NUM>. For a respective peer layer (RRC or NAS) at the UE <NUM>, a counterpart RRC layer may reside in the base station <NUM> and a counterpart NAS layer in an entity of the core network <NUM> (e.g., entity <NUM>). Below the RRC, a PDCP layer may transfer NAS/RRC messages via signaling radio bearers (SRBs). Similar to the user plane, the PDCP may then be followed by RLC, MAC, and PHY, as generally described above with respect to the user plane.

The protocol stacks can provide for a variety of channels of communications. For examples, a set of "logic channels" may be provided for user and control data transfer between an RLC layer and a MAC layer; a set of "transport channels" between a MAC layer and a PHY layer; a set of "physical channels" may carry physical layer data and/or signals over the wireless medium (e.g., over the air interface) between a UE <NUM> and a base station <NUM>. Generally speaking, a layer may receive, as an input, a service data unit (SDU) from a layer above, generate one or more protocol data units (PDUs), e.g., by adding headers to the received SDU, and pass the generated PDUs to a layer below for further processing.

Besides communicating with a wireless wide area network (WWAN), a UE110 may communicate with a wireless local area network (WLAN), such as a Wireless-Fidelity (Wi-Fi) network. A WLAN <NUM> may include a wireless access point (AP), such as a wireless "hotspot" or "router" coupled to the Internet. A user device served by a wireless access point may also be referred to as an access terminal (AT). An AP <NUM> may wirelessly communicate with a UE <NUM> and may relay packetized communication data (e.g., IP packets) between the UE <NUM> and the Internet (or another AT). A WWAN (e.g., the core network <NUM>) may support inter-networking (including aggregation) with a WLAN, and a UE <NUM> may communicate with both a base station <NUM> and an AP <NUM>.

A UE <NUM>, a base station <NUM>, or an AP <NUM> may communication with one another in millimeter wave spectrum. Generally antenna arrays or panels can be used to direct signal energy in multiple directions or beams. A communication link from a first node to a second node can be realized through a transmitter beam at the first node and a receiver beam at the second node. As described in detail below, wireless nodes may switch between full duplex and half duplex based on self-interference measurements.

For illustrative purposes, the following examples and figures may be described with reference to the user or network devices of <FIG>; however, other types of user or network devices may be used in same or other examples without limiting the scope of the present disclosure.

<FIG> illustrate an example of half-duplex system and an example of full-duplex system, respectively. Two wireless nodes, e.g., node <NUM> and node <NUM>, each equipped with a transmitter (TX) and a receiver (RX), may communicate with each other in a half-duplex mode (<FIG>) or in a full-duplex mode (<FIG>). The term "wireless node" refers to a broad variety of wireless communication devices. In particular, the node <NUM> or the node <NUM> can refer to either a UE <NUM> or a base station <NUM> as described in <FIG>. Thus, communications between the node <NUM> and the node <NUM> may represent communications between a UE and a base station (e.g., as in uplink/downlink cellular communications), between two UEs (e.g., as in device-to-device communications), or between two base stations (e.g., as in backhaul communications). In general, a half-duplex or full-duplex node may transmit to and/or receive from different nodes, rather than a same node as depicted in the figures (for convenience of description).

As illustrated in <FIG>, half-duplex communications between two nodes may take place only on one direction at any given time. For example, while a node <NUM> may, at a particular time instance, transmit a signal/message to a node <NUM> on a direction (or path) <NUM>, from a TX <NUM> at the node <NUM> to a RX <NUM> at the node <NUM>, the node <NUM> may not simultaneously receive a signal/message from the node <NUM> on an opposite direction. In order for the node <NUM> to receive from the node <NUM>, the two nodes may use another time instance during which the node <NUM> may transmit a signal/message to the node <NUM> on an opposite direction <NUM>, from a TX <NUM> at the node <NUM> to a RX <NUM> at the node <NUM>.

In contrast, as illustrated in <FIG>, full-duplex communications between two nodes can occur simultaneously on both directions. For example, at a given time instance, a node <NUM> and a node <NUM> can both transmit and receive signals/messages from each other, that is, on a direction <NUM> (from the node <NUM> to the node <NUM>) and on an opposite direction <NUM> (from the node <NUM> to the node <NUM>) at the same time. From the perspectives of a node, rather than being limited to either transmit or receive (but not both) in half duplex, the node in full duplex can simultaneously transmit and receive signals/messages.

Full duplex can be achieved in various ways. When multiple frequencies are available as in the case of frequency division multiple access or carrier aggregation, two communication directions may be assigned to resources separated in different frequencies. For example, communications on the direction <NUM> may take place in a carrier frequency, while the communications on the direction <NUM> another carrier frequency. Even at the same frequency, full duplex can be realized through separation in other communication dimensions, such as spatial dimension, code dimension, and so on. For example, in millimeter wave applications, a millimeter wave node may communicate with other nodes on a pair of transmitter and receiver beams separated in spatial dimensions.

Different duplex modes (full duplex or half duplex) generally entail different benefit and cost tradeoffs. Compared to half duplex, full duplex can significantly increase communication rate and spectral efficiency because simultaneous transmission and reception afforded by full duplex can lead to higher utilization of communication resources. On the other hand, a full-duplex implementation may impose higher cost/complexity than a half-duplex alternative. As further elaborated below, self-interference from the transmitter to the receiver poses a particular challenge in design and performance of full-duplex systems. More complex circuitry may be used to provide adequate TX to RX isolation for full-duplex operations.

<FIG> illustrates impact of clutters on self-interference in full duplex wireless nodes. In millimeter-wave communication, wireless nodes generally communicate with each other on various transmitter (TX) and receiver (RX) beams created through multiple antennas. Narrow, highly directional beams in millimeter wave spectrum may provide sufficient spatial isolation to support full duplex wherein a millimeter-wave node may transmit on a TX beam and simultaneously receive on a RX beam. The scattering environments, clutters in particular, can impact the performance of full duplex communication.

For convenience of discussion, two nodes each with a pair of beams are shown in <FIG>: a TX beam <NUM> and an RX beam <NUM> are at Node <NUM>; a TX beam <NUM> and an RX beam <NUM> at Node <NUM>. A line of sight (LOS) path from the TX beam <NUM> of Node <NUM> to the RX beam <NUM> of Node <NUM> constitutes a main path of communication direction from Node <NUM> to Node <NUM>; a reflective path from the TX beam <NUM> of Node <NUM> to the RX beam <NUM> of Node <NUM> constitutes a main path of an opposite communication direction from Node <NUM> to Node <NUM>. Intended signals/messages are transmitted and received on the main path of the respective communication direction. Generally speaking, a transmitted signal from a TX node in a certain direction may either reach a RX node or not, depending on wireless propagation environments. For example, if there are good or dominant clusters in the channel that reflect, diffract, or scatter the transmitted energy from the TX direction, then the signal is likely seen along the intended RX direction at the RX node. Otherwise, the transmitted energy may not be seen or sufficiently received at the RX node in the RX direction.

In half duplex, since a node may not transmit and receive at the same time, the above two paths are active only one at a time. Thus, when a node receives on its RX beam, its TX beam is silent, thus avoiding self-interference from TX beam to RX beam at the same node.

In full duplex, however, as a node may transmit and receive at the same time, transmission on a TX beam may cause self-interference on the reception on a RX beam of the same node. In some scenarios, self-interference by the TX beam could seriously degrade the quality of the received signal at the RX beam.

The presence and extent of self-interference generally depend on the presence, location, or other characters of clutters. A clutter is a reflector, diffractor, or scatterer in the environment that transfers energy from TX to RX. For example, as illustrated in <FIG>, the RX beam <NUM> may receive interference from the TX beam <NUM> via Clutter <NUM>, Clutter <NUM>, and/or Clutter <NUM>. Some of the clutters may be static (e.g., Clutter <NUM> and Clutter <NUM>), others dynamic, moving, or time-varying (e.g., Clutter <NUM>). Similarly, the TX beam <NUM> may cause interference to the RX beam <NUM> via Clutter <NUM>. The interference can lead to reduced signal-to-interference-and-noise ratio (SINR) or other signal quality metrics on an RX path. An RX beam may experience different degrees of degradation depending on the direction of a self-interference signal path from a TX beam: more impact when the self-interference path comes towards the RX beam's main lobe rather than other directions, such as side lobes, because of higher reception of incoming signal at the main lobe. For example, as seen in <FIG>, self-interference path via Clutter <NUM>, hitting the main lobe of the RX beam <NUM>, may cause more interference than other self-interference paths, via Clutter <NUM> or Clutter <NUM>, hitting a side lobe.

<FIG> illustrates an example of a network <NUM> supporting duplex mode determination and switching in accordance with the present disclosure. Multiple wireless nodes (e.g., millimeter-wave nodes) may communicate with one another on various transmitter and/or receiver beams. For example, a node <NUM> may transmit to a node <NUM> on a TX beam <NUM> and to a node <NUM> on a TX beam <NUM>; it may receive from the node <NUM> on an RX beam <NUM> and from the node <NUM> on an RX beam <NUM>. Similarly, the node <NUM> may transmit to the node <NUM> on a TX beam <NUM> and to the node <NUM> on a TX beam <NUM>; it may receive from the node <NUM> on an RX beam <NUM> and from the node <NUM> on an RX beam <NUM>. Correspondingly, the node <NUM> may transmit to the node <NUM> on a TX beam <NUM> and to the node <NUM> on a TX beam <NUM>; it may receive from the node <NUM> on an RX beam <NUM> and from the node <NUM> on an RX beam <NUM>.

A wireless node may communicate with one or more other wireless nodes on a "beam pair" comprising a transmitter beam and a receiver beam both at the same wireless node. In general, a wireless node can have multiple beam pairs. For example, at the node <NUM>, a beam pair (TX beam <NUM> and RX beam <NUM>) may provide a transmission link to, and reception link from, the node <NUM>, whereas another beam pair (TX beam <NUM> and RX beam <NUM>) may provide a transmission link to the node <NUM> but a reception link from the node <NUM>.

A wireless node in the network <NUM> may communicate with one or more other nodes in half duplex or full duplex and may dynamically switch between the two duplex modes. A suitable pair of TX and RX beam and its associated duplex mode may be determined dynamically (e.g., as varying from slot to slot) or semi-statically (as static in a relatively longer time scale). Moreover, the determination can be implemented in a centralized or a decentralized manner. Although a determination unit <NUM> is shown in <FIG> as centralized, the techniques and principles described herein can readily be adapted to a decentralized implementation where an individual node may make autonomous decision with no or less input from other nodes. Generally speaking, a centralized determination may attain a global optimization in system performance across multiple wireless nodes.

The duplex mode may be determined based on self-interference measurements. A wireless node may perform "full-duplex beam training" to measure self-interference for one or more beam pairs at the wireless node. As generally described with reference to <FIG>, self-interference for a beam pair in full duplex can significantly affecting full duplex performance, thus impacting the choice of full duplex or half duplex. The effect of self-interference may be measured in terms of various metrics, such as signal-to-interference-and-noise ratio (SINR), reference signal received power (RSRP), reference signal received quality (RSRQ), or signal-to-interference ratio (SIR).

A full-duplex beam training may generally involve a beam sweeping in either or both of TX and RX beams. For example, a wireless node may first sweep TX beams for a particular RX beam to measure self-interference for various corresponding beam pairs, and then repeat the TX beam sweeping for other RX beams. A wireless node may conduct beam training as a self-measurement procedure, separate from active data communications, or it may leverage active full-duplex communication sessions to gather interference statistics. In some cases, the beam training may involve a limited subset of potential beam pairs.

A beam pair may be chosen for full duplex based on the self-interference measurements. For example, a "good" TX/RX beam pair with lower self-interference may be used for communication in full duplex. In a decentralized design, a wireless node may determine which beam pair to use based on the result of beam training. In a centralized design, however, a wireless node may report the self-interference measurements (e.g., in a measurement report) to the determination unit <NUM>. The determination unit <NUM> may aggregate self-interference measurements from more than one wireless node, determine suitable beam pairs and associated duplex modes for wireless nodes, and notify the wireless nodes of the determined beam pairs/duplex modes. In some cases, the (centralized) determination unit <NUM> may select a beam pair, which may not have the least self-interference locally at a particular wireless node but may deliver better performance globally with a corresponding beam pair at another wireless node.

The duplex mode and beam pair determination may be further based on rate measurement. There are situations where for a beam pair, full duplex may not necessarily outperform half duplex. For example, due to relatively high self-interference in full duplex, half duplex may produce higher communication rate (or throughput) despite having a less or poor utilization of communication resources. In one aspect, for a beam pair, the rate for full duplex taking into account the self-interference can be calculated and compared to the rate for half duplex with no self-interference but with a resource utilization loss. Depending on the rate comparison, either full duplex or half duplex may be chosen for the beam pair; for example, the duplex mode having higher rate may be selected. Based on rate measurements, beam pairs with associated duplex modes, having higher rates, may be selected and determined over other beam pairs having lower rates. In general, in centralized design, best beam pairs may be network coordinated and configured for optimal performance across a multitude of nodes served by the network. The network, e.g., via determination unit <NUM>, may configure rate measurement, for example, defining an effective rate. In certain deployments (e.g., an Integrated Access and Backhaul Network or a cellular network with a central/intelligent entity), a wireless node may report measurements (e.g., self-interference and/or rate measurements) to a Central Unit (CU) which may determine a best beam pair and the effective rate for Distributed Units (DUs).

In addition, latency constraints can be taken into account for deciding between full duplex and half duplex. Because of simultaneous communications on two directions, full duplex may be preferred for low latency applications. For example, a very stringent latency constraint (e.g., below a threshold) may override the rate comparison (which might otherwise favor half duplex), if the achievable rate for full duplex, though lower than the rate for half duplex, can still support the application. For a less stringent latency, the latency loss due to half duplex may be weighted together with achievable rates for duplex mode determination. For example, gaming or mission critical applications can favor latency as a metric with more weightage than the achieved rates.

<FIG> illustrates an example of a method <NUM> of wireless communication in accordance with the present disclosure. The method <NUM> may encompass various aspects of the techniques described with reference to <FIG>. The method <NUM> may be performed by a wireless node (or its components). As in <FIG>, the wireless node may refer to a UE, a base station, or other wireless communication device. In particular, the wireless node may be a millimeter-wave node that may transmit and receive wireless signals in millimeter wavelengths or bands. The method <NUM> may be implemented in hardware, firmware, or software, or a combination thereof.

At <NUM>, a wireless node (e.g., a millimeter-wave node) may measure a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at the wireless node. For example, the wireless node may measure self-interference for one or more beam pairs, using a general or limited beam training as described with reference to <FIG>. In particular, for a particular beam pair, the wireless node may measure an amount of interference from the TX beam to the RX beam in full duplex. Various metrics can be measured, such as signal-to-interference-and-noise ratio (SINR), reference signal received power (RSRP), reference signal received quality (RSRQ), or signal-to-interference ratio (SIR), or some combinations thereof.

The determination for beam pairs and associated duplex modes can be made locally at the wireless node, or remotely at a central unit (e.g., the determination unit <NUM> in <FIG>), or jointly by the wireless node and the central unit. In case of a centralized design, the wireless node may report the metric to a network entity for duplex mode determination. The network entity may be a central unit connected to one or more distributed wireless nodes. An example of the network entity may be a base station (or its components) determining duplex mode and/or beam pairs for UEs, distributed units, remote radio heads, etc., served by or connected to the base station. The network entity may notify various wireless nodes of the duplex mode/beam pair determination through control signaling or messages (e.g., RRC messages or MAC Messages); in response, the wireless nodes may receive such notification and apply the determination accordingly. In case of decentralized design, a wireless node may determine beam pair and/or duplex mode based on local self-interference measurements on its own TX beams and RX beams. In some scenarios, a wireless node may autonomously determine a suitable beam pair and its associated duplex mode, for example, by selecting a TX-RX beam pair for full duplex that has best SINR with least self-interference and/or higher rate compared to half duplex.

As generally described with reference to <FIG>, the duplex mode (full duplex or half duplex) can be determined based on self-interference metric. Various performance metric, such as communication rate, may be derived from the self-interference metric. The duplex mode may be determined by the self-interference metric itself , derived metrics (such as rate), or combination thereof. Optionally non-interference criterion, such as latency, may additionally be used. In addition, the duplex mode determination may also select suitable beam pairs for one or more wireless nodes, based at least on the self-interference metrics. For example, a beam pair may be selected over a different beam pair for full duplex based on the beam pair having lower self-interference. For a beam pair, the duplex mode may be determined based on a rate comparison between full duplex and half duplex for the beam pair, based on self-interference metric. For example, a beam pair with its associated duplex mode may be selected over a different beam pair based on the beam pair having a higher rate. In addition, the duplex mode may be determined further based on a latency constraint.

At <NUM>, the wireless node may communicate, on a beam pair, in full duplex or half duplex based on the (self-interference) metric. Based on the self-interference metrics, the wireless node may determine, or obtain determination of, a duplex mode for a beam pair. The wireless node may switch from half duplex to full duplex, or vice versa, depending on the determination.

<FIG> illustrates an example of an apparatus <NUM> in accordance with the present disclosure. The apparatus <NUM> may be an example of a wireless node described above with reference to <FIG>. In particular, the apparatus <NUM> may include a receiver <NUM>, a transmitter <NUM>, and a duplex mode controller <NUM>, and may perform various aspects of the method <NUM> described with reference to <FIG>.

The receiver <NUM> may be configured to receive signals or channels carrying information such as packets, user data, or control information associated with various information channels. Information may be passed on to other components of the apparatus. The receiver <NUM> may utilize a single antenna or a set of multiple antennas, which may provide a set of one or more receiver (RX) beams.

The transmitter <NUM> may be configured to transmit signals or channels generated by other components of the apparatus. The transmitter <NUM> may utilize a single antenna or a set of multiple antennas, which may provide a set of one or more transmitter (TX) beams.

The receiver <NUM> and transmitter <NUM> (or a transceiver incorporating both) may be coupled to the duplex mode controller <NUM> and may provide means for communication between the apparatus <NUM> with other devices, such as wireless nodes (e.g., millimeter-wave nodes).

The duplex mode controller <NUM> may be a baseband modem or an application processor or may illustrate aspects of a baseband or application processor. The duplex mode controller <NUM> or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Software may comprise codes or instructions stored in a memory or like medium that is connected or in communication with the processor described above. The codes or instructions may cause the processor, the apparatus <NUM>, or one or more components thereof to perform various functions described herein.

The duplex mode controller <NUM> may control, coordinate, or execute various functions supporting switching between full duplex and half duplex for millimeter-wave communications. The duplex mode controller <NUM> may further include a measurement unit <NUM>, an (optional) duplex mode determination unit <NUM>, and a duplex mode switcher <NUM>.

The measurement unit <NUM> may provide means for measuring a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter beam and a receiver beam both at a wireless node, and may, for example, be configured to perform the method <NUM> at <NUM> described with reference to <FIG>.

The duplex mode switcher <NUM> may provide means for communicating, on a beam pair, in full duplex or half duplex based on the (self-interference) metric, and may, for example, be configured to perform the method <NUM> at <NUM> described with reference to <FIG>. In particular, the duplex mode switcher <NUM> may switch between full duplex and half duplex according to a duplex mode determined or configured based on self-interference metric. The duplex mode may be switched dynamically or semi-statically.

The duplex mode controller <NUM> may optionally include the duplex mode determination unit <NUM> to determine duplex mode and/or beam pair in a local or decentralized manner. As described with reference to <FIG> and <FIG>, the duplex mode determination unit <NUM> may determine duplex mode, and additionally select a suitable beam pair, for communication, based on self-interference metrics, as well as additionally based on rate, latency, or other performance criteria. In a centralized design, the duplex mode determination unit <NUM> may be absent. Alternatively, the duplex mode determination unit <NUM> may be adapted to interworking with a remote determination unit (e.g., determination unit <NUM> in <FIG>), for example, reporting self-interference measurements (and/or other measurements, such as rates) to a network entity such as the remote determination unit, obtaining the determination (e.g., receiving notification) from the network entity, etc..

<FIG> illustrates an example of a wireless node <NUM> in accordance with the present disclosure. The wireless node <NUM> may be an example of the apparatus <NUM> described with reference to <FIG>. The wireless node <NUM> may comprise duplex mode controller <NUM>, processor <NUM>, memory <NUM>, software <NUM>, transceiver <NUM>, antenna <NUM>, and I/O controller <NUM>. These components may be coupled or in electronic communication via one or more buses (e.g., bus <NUM>). The wireless node <NUM> may communicate wirelessly with other wireless nodes, e.g., in millimeter waves, on various transmitter and/or receiver beams.

The duplex mode controller <NUM> may perform various functions supporting switching between full duplex and half duplex for millimeter-wave communications. For example, the duplex mode controller <NUM> may be configured to measure a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at a wireless node, and to communicate, on the beam pair, in full duplex or half duplex based on the metric. In some examples, the duplex mode controller <NUM> may implement the duplex mode controller <NUM> described with reference to <FIG>. Generally speaking, the duplex mode controller <NUM> may utilize processor <NUM> and memory <NUM> to execute its functionalities.

Processor <NUM> may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor <NUM> may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor <NUM>. Processor <NUM> may be configured to execute computer-readable instructions (e.g., software <NUM>) stored in a memory (e.g., memory <NUM>) to perform various functions.

Memory <NUM> may include random access memory (RAM) and/or read only memory (ROM). The memory <NUM> may store computer-readable, computer-executable software <NUM> including instructions that, when executed, cause the processor <NUM> (or the wireless node <NUM> generally) to perform various functions described herein.

Software <NUM> may include codes implementing aspects of the present disclosure, e.g., described with reference to <FIG>, <FIG> and <FIG>. For example, the software <NUM> may include codes for measuring a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter (TX) beam and a receiver (RX) beam both at a wireless node, and for communicating, on the beam pair, in full duplex or half duplex based on the metric. Software <NUM> may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software <NUM> may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

The transceiver <NUM> may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets from signals received from the antennas. In some examples, the transceiver <NUM> may include both the receiver <NUM> and the transmitter <NUM> described with reference to <FIG>.

In some cases, the wireless node <NUM> may include a single antenna <NUM>. However, in some cases the wireless node <NUM> may have more than one antenna <NUM>, which may be capable of concurrently transmitting and/or receiving multiple wireless transmissions.

I/O controller <NUM> may manage input and output signals for the wireless node <NUM>. I/O controller <NUM> may also manage peripherals not integrated into the wireless node <NUM>. In other cases, I/O controller <NUM> may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or other device. In some cases, a user may interact with the wireless node <NUM> via I/O controller <NUM> or via hardware components controlled by I/O controller <NUM>.

The term "exemplary," if used herein, means "serving as an example, instance, or illustration," and not "preferred" or "advantageous over other examples.

As used herein, the phrase "based on" shall not be construed as a reference to a closed set of conditions.

As used herein, the conjunction "or" shall generally be interpreted as "inclusive" unless the context indicates otherwise. For example, "A or B" would generally mean "either A, or B, or both" (but not necessarily "either A, or B, but not both"); in other words, the presented alternatives ("A" and "B") need not necessarily be mutually exclusive. Certain context, however, can indicate an "exclusive or," as in "whether A or not," for example.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices (e.g., a combination of a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

By way of example, and not limitation, non-transitory computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, digital subscriber line, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.

Claim 1:
A method (<NUM>) of wireless communication, comprising:
measuring (<NUM>) a metric of self-interference for a beam pair, wherein the beam pair comprises a transmitter, TX, beam and a receiver, RX, beam both at a wireless node; and
communicating (<NUM>), on the beam pair, in full duplex or half duplex based on the metric, wherein a duplex mode for the beam pair is determined based on the metric, on a rate comparison between full duplex and half duplex for the beam pair and further based on a latency constraint.