Patent Application
20240031044
The disclosure relates to a method and device for measuring interference in a wireless communication system. Further, the disclosure relates to a method and device for measuring self-interference during a full duplex operation of an integrated access backhaul (TAB) in a wireless communication system.
Looking back at the evolution of wireless communication generations, technologies for human services, such as voice, multimedia, and data, have been developed. After the commercialization of 5th-generation (5G) communication systems, it is expected that the explosive growth of connected devices will be connected to communication networks. Examples of objects connected to the network may include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors such as augmented reality glasses, virtual reality headsets, and hologram devices. In the 6th-generation (6G) era, in order to provide various services by connecting hundreds of billions of devices and objects, efforts are being made to develop an improved 6G communication system. For this reason, the 6G communication system is referred to as a beyond 5G communication. In the 6G communication system expected to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabytes) bps, and a wireless delay time is 100 microseconds (μsec). That is, a transmission speed in the 6G communication system is 50 times faster than that in the 5G communication system and a wireless delay time thereof is reduced to 1/10.
To achieve such high data rates and ultra-low latency, the 6G communication system is being considered for implementation in a terahertz band (e.g., 95 gigahertz (95 GHz) to 3 terahertz (3 THz) band). In the terahertz band, it is expected that the importance of technology that can ensure signal reach, that is, coverage, will increase due to more serious path loss and atmospheric absorption compared to a mmWave band introduced in 5G. As main technologies for ensuring coverage, multi-antenna transmission technologies such as radio frequency (RF) elements, antennas, new waveforms better in terms of coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and massive multiple-input and multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, and large scale antenna should be developed. Further, in order to improve coverage of terahertz band signals, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed.
Further, in order to improve frequency efficiency and system network, in the 6G communication system, development of full duplex technology in which uplink and downlink simultaneously utilize the same frequency resource at the same time, network technology that integrates satellite and high-altitude platform stations (HAPS), network structure innovation technology that supports mobile base stations and that enables network operation optimization and automation, dynamic frequency sharing technology through collision avoidance based on spectrum use prediction, artificial intelligence (AI)-based communication technology that utilizes AI from a design stage and internalizes end-to-end AI support functions to realize system optimization, and next-generation distributed computing technology that realizes complex services that exceed the limits of UE computing capabilities by utilizing ultrahigh performance communication and computing resources (mobile edge computing (MEC), cloud, and the like) is being made. Further, through the design of a new protocol to be used in the 6G communication system, the implementation of a hardware-based security environment, the development of mechanisms for safe use of data, and the development of technology on a method for maintaining privacy, attempts to further strengthen connectivity between devices, to further optimize networks, to promote softwareization of network entities, and to increase the openness of wireless communications are continuing.
Due to the research and development of such 6G communication systems, it is expected that a new level of next hyper-connected experience will be possible through the hyper-connectivity of the 6G communication system including not only connections between objects but also connections between people and objects. Specifically, it is expected that services such as truly immersive extended reality (XR), high-fidelity mobile hologram, and digital replica will be available through the 6G communication system. Further, as a service such as remote surgery, industrial automation and emergency response through security and reliability enhancement is provided through 6G communication systems, it will be applied in various fields such as industry, medical care, automobiles, and home appliances.
Various embodiments of the disclosure provide an improved method and device for measuring interference in a wireless communication system. Further, various embodiments of the disclosure provide a method and device for measuring self-interference during a full duplex communication operation of an integrated access backhaul in a wireless communication system.
According to an embodiment of the disclosure, a method performed by a first node for measuring self-interference may include acquiring a self-interference channel measurement configuration; transmitting a measurement signal for measuring self-interference based on the self-interference channel measurement configuration; and measuring the self-interference generated by the measurement signal for measuring the self-interference channel based on the self-interference channel measurement configuration.
Further, according to an embodiment of the disclosure, a first node for self-interference measurement may include a transceiver; and a controller configured to control to acquire a self-interference channel measurement configuration, to transmit a measurement signal for self-interference measurement based on the self-interference channel measurement configuration, and to measure the self-interference generated by a measurement signal for self-interference channel measurement based on the self-interference channel measurement configuration.
According to various embodiments of the disclosure, an improved method and device for measuring interference in a wireless communication system can be provided. Further, according to various embodiments of the disclosure, a method and device for measuring self-interference during a full duplex operation of an integrated access backhaul in a wireless communication system can be provided.
A wireless communication system has evolved from providing voice-oriented services in the early days to a broadband wireless communication system that provides high-speed and high-quality packet data services as in communication standards such as high speed packet access (HSPA), long term evolution (LTE) or evolved universal terrestrial radio access (E-UTRA), LTE-Advanced (LTE-A), and LTE-Pro of 3GPP, high rate packet data (HRPD) and ultra mobile broadband (UMB) of 3GPP2, and IEEE 802.16e.
LTE and NR systems, which are a representative example of the broadband wireless communication system, employ an orthogonal frequency division multiplexing (OFDM) scheme (or cyclic prefix based orthogonal frequency division multiplex (CP-OFDM) scheme) in downlink (DL) and a single carrier frequency division multiple access (SC-FDMA) scheme (or discrete Fourier transform spread OFDM (DFT-s-OFDM) scheme) or CP-OFDM scheme in an uplink. The uplink means a radio link that a terminal (user equipment (UE) or mobile station (MS)) transmits data or control signals to a base station (a generation node B (gNB), an eNode B (eNB), or a base station (BS) is a node capable of allocating radio resources to a plurality of terminals, and radio access technology supported by the base station is not limited), and the downlink means a radio link in which a base station transmits data or control signals to a terminal. The above-mentioned multiple access method enables data or control information of each user to distinguish by allocating and operating data or control information so that time-frequency resources to carry data or control information for each user in general do not overlap each other, that is, so that orthogonality is established.
A 5G communication system, which is a future communication system after LTE, should support services that simultaneously satisfy various requirements so that various requirements of users and service operators may be freely reflected. Services considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra reliability low latency communication (URLLC), and the like.
In a general wireless communication system, a specific spectrum resource (hereinafter, may be used interchangeably with a frequency resource) is exclusively allocated for a specific service. Representatively, in the case of cellular communication, a country leases a specific spectrum resource to a specific mobile communication operator, and a mobile communication operator to which the resource is allocated maintains a cellular network exclusively using the resource. However, resources are being wasted because the spectrum allocated to each mobile communication operator is not fully utilized, except for spatiotemporal situations in which data traffic is very high.
In order to solve such a situation, a situation in which dynamic frequency sharing between mobile communication operators is possible may be considered. A spectrum resource having a right to use first may be allocated to each operator, but when a use amount of the resource is low, permission to use the resource may be granted to other operators. In the above scenario, operators do not need to allocate unnecessarily large amounts of spectrum in order to cope with peak traffic situations. Therefore, a dynamic frequency sharing system between operators will be a base technology for 6G or 5G communication systems that can efficiently manage increasingly scarce spectrum resources.
Prior to describing the details, a frame structure of LTE and LTE-A systems will be described in more detail with reference to drawings. The following resource structure illustrates a resource structure of LTE and LTE-A systems, but a similar resource structure may be applied to 5G or other communication systems.
Hereinafter, downlink control information (DCI) in LTE and LTE-A systems will be described in detail.
In the LTE system, scheduling information on downlink data or uplink data is transmitted from a base station to a UE through DCI. DCI is defined in various formats, and a determined DCI format is applied according to whether it is scheduling information on uplink data or scheduling information on downlink data, whether it is compact DCI with a small size of control information, whether spatial multiplexing using multiple antennas is applied, or whether it is DCI for power control. For example, a DCI format 1, which is scheduling control information on downlink data includes at least the following control information.
The DCI is transmitted through a PDCCH, which is a downlink physical control channel through channel coding and modulation processes. A cyclic redundancy identify (CRC) is attached to a DCI message payload, and the CRC is scrambled with a UE identifier (e.g., cell-radio network temporary identifier (C-RNTI)) corresponding to the identity of the UE. Different radio network temporary identifiers (RNTIs) are used according to a purpose of the DCI message, for example, according to UE-specific data transmission, a power control command, or a random access response (RAR), and the like. That is, the RNTI is not explicitly transmitted, but is included in the CRC calculation process and transmitted. Upon receiving the DCI message transmitted on the PDCCH, the UE may identify a CRC using the assigned RNTI, and if the CRC identification result is correct, it can be seen that the corresponding message has been transmitted to the UE.
A cell-specific RS (CRS) 203 is used as a reference signal (RS) for decoding the PDCCH 201. The CRS 203 is transmitted every subframe over all bands, and scrambling and resource mapping vary according to a cell identity (ID) (e.g., physical cell ID (PCI)). Because the CRS 203 is a reference signal commonly used by all UEs, UE-specific beamforming cannot be used. Therefore, the multi-antenna transmission technique for the PDCCH of the LTE system is limited to open-loop transmit diversity. The number of ports of the CRS is implicitly known to the UE from decoding of a physical broadcast channel (PBCH).
Resource allocation of the PDCCH 201 is performed based on a control-channel element (CCE), and one CCE is composed of 9 resource element groups (REGs), that is, total 36 REs (one REG is composed of 4 REs). The number of CCEs necessary for a specific PDCCH 201 may be 1, 2, 4 or 8, which varies according to a channel coding rate of a DCI message payload. In this way, different numbers of CCEs are used for implementing link adaptation of the PDCCH 201. The UE should detect a signal without knowing information on the PDCCH 201, and in the LTE system, a search space representing a set of CCEs is defined for such blind decoding. The search space is composed of a plurality of sets in an aggregation level (AL) of each CCE, which is not explicitly signaled but may be implicitly defined through a function and subframe number by the UE identity. Within each subframe, the UE decodes the PDCCH 201 for all possible resource candidates that may be created from CCEs within the configured search space, and processes information declared valid for the corresponding UE through CRC identification.
The search space is classified into a UE-specific search space and a common search space. Because the UE-specific search space is implicitly defined through a function and subframe number by the UE identity without being explicitly signaled, the UE-specific search space may change according to the subframe number, which means that a search space may be changed over time. Thereby, the problem (defined as a blocking problem) that a specific UE cannot use a search space by other UEs among UEs may be solved. Because all CCEs for which a UE searches are already being used by other UEs scheduled in the same subframe, when any UE is not scheduled in a corresponding subframe, such a search space changes over time; thus, such a problem may not occur in the next subframe. For example, even if parts of the UE-specific search spaces of a UE #1 and a UE #2 overlap in a specific subframe, a UE-specific search space changes for each subframe; thus, it may be expected that the overlap in the next subframe is different from this.
In the case of a common search space, because a certain group of UEs or all UEs should receive a PDCCH, it is defined as a pre-promised set of CCEs. That is, the common search space does not change according to the identity of the UE or the subframe number. In order to receive cell common control information such as paging messages or dynamic scheduling for system information, a certain group of UEs or all UEs may search for the common search space of the PDCCH 201. For example, the UE may search for the common search space of the PDCCH 201 to receive scheduling allocation information of a DL-SCH for transmission of system information block (SIB)-1 including cell operator information. Further, although the common search space exists for transmission of various system messages, it may also be used for transmitting control information of an individual UE. Thereby, the common search space may be used as a solution to a phenomenon in which a UE does not receive scheduling due to lack of available resources in the UE-specific search space.
A search space for an LTE PDCCH is defined as illustrated in Table 1.
In the LTE system, a UE has a plurality of search spaces according to each AL. The number of PDCCH candidates to be monitored by the UE within the search space defined according to the AL in the LTE system is defined in Table 2.
According to Table 1, in the case of a UE-specific search space, AL {1, 2, 4, 8} is supported, and in this case, {6, 6, 2, 2} number of PDCCH candidates are respectively provided. In the case of a common search space 302, AL {4, 8} is supported, and in this case, {4, 2} number of PDCCH candidates are respectively provided. The reason why the AL supports only {4, 8} in the common search space is to improve coverage characteristics because system messages generally have to reach the edge of a cell.
DCI transmitted to the common search space is defined only for a specific DCI format such as 0, 1A, 3, 3A, or 1C corresponding to usage such as system message or power control for a UE group. A DCI format with spatial multiplexing is not supported within the common search space. A downlink DCI format to be decoded in the UE-specific search space is changed according to a transmission mode configured for the corresponding UE. Because a configuration of the transmission mode is performed through radio resource control (RRC) signaling, the accurate subframe number for when the configuration takes effect for the corresponding UE is not designated. Therefore, the UE may operate while maintaining a connected state by always performing decoding for a DCI format 1A regardless of the transmission mode.
In the above description, a method of transmitting and receiving a downlink control channel and downlink control information in LTE and LTE-A and a search space have been described. In the following description, a downlink control channel in a 5G communication system will be described in more detail with reference to the drawings.
By concatenating REGs 303 illustrated in
The basic unit, that is, the REG 303 of the downlink control channel illustrated in
The control resource set in the 5G system described above may be configured by the base station to the UE through higher layer signaling (e.g., system information, master information block (MIB), radio resource control (RRC) signaling). Configuring the control resource set to the UE means providing at least one of information such as a position of a control resource set, a subband, resource allocation of the control resource set, and a control resource set duration. For example, information for configuring the control resource set described below may include at least one of information in Table 3.
In addition to the configuration information of Table 3, various type of information necessary for transmitting a downlink control channel may be configured to the UE.
Hereinafter, DCI in the 5G system will be described in detail.
In the 5G system, scheduling information on uplink data transmitted on a physical uplink shared channel (PUSCH) or downlink data transmitted on a PDSCH is transmitted from a base station to a UE through DCI. The UE may monitor a DCI format for fallback and a DCI format for non-fallback with respect to a PUSCH or a PDSCH. The DCI format for fallback may be composed of a fixed field between the base station and the UE, and the DCI format for non-fallback may include a configurable field.
DCI for fallback scheduling a PUSCH may lude, for example, information in Table 4.
DCI for non-fallback scheduling a PUSCH may include, for example, information in Table 5.
DCI for fallback scheduling a PDSCH may include, for example, information in Table 6.
DCI for non-fallback scheduling a PDSCH may include, for example, information in Table 7.
The DCI may be transmitted through a PDCCH via channel coding and modulation processes. A CRC is attached to a DCI message payload, and the CRC is scrambled with an RNTI corresponding to the identity of the UE. Different RNTIs are used according to the purpose of the DCI message, e.g., UE-specific data transmission, power control command, or random access response. That is, it means that the RNTI is not transmitted explicitly but is included in a CRC calculation process and transmitted. Upon receiving the DCI message transmitted on the PDCCH, the UE identifies a CRC using the allocated RNTI, and if the CRC identification result is correct, it can be seen that the corresponding message has been transmitted to the UE.
For example, DCI scheduling a PDSCH for system information (SI) may be scrambled with a system information-RNTI (SI-RNTI). DCI scheduling a PDSCH for a RAR message may be scrambled with a random access-RNTI (RA-RNTI). DCI scheduling a PDSCH for a paging message may be scrambled with a paging-RNTI (P-RNTI). DCI notifying a slot format indicator (SFI) may be scrambled with a slot format indicator-RNTI (SFI-RNTI). DCI notifying transmit power control (TPC) may be scrambled with a transmit power control-RNTI (TPC-RNTI). DCI scheduling UE-specific PDSCH or PUSCH may be scrambled with a cell-RNTI (C-RNTI).
When a specific UE is scheduled for a data channel, that is, a PUSCH or PDSCH, through the PDCCH, data is transmitted and received together with the DMRS within the scheduled resource set.
expressed in
As described above, in order to measure a downlink channel state in a cellular system, a base station should transmit a reference signal. In the case of a long term evolution advanced (LTE-A) system of 3GPP, a UE may measure a channel state between the base station and the UE using a CRS or channel state information-reference signal (CSI-RS) transmitted by the base station. The channel state should be measured considering various factors, which may include an amount of interference in downlink. The amount of interference in the downlink includes an interference signal and thermal noise generated by an antenna belonging to a neighboring base station, and the amount of interference in the downlink is important for the UE to determine a downlink channel situation. For example, in the case that a base station with one transmission antenna transmits a signal to a UE with one reception antenna, the UE should determine Es/Io by determining energy per symbol that may be received in the downlink from a reference signal received from the base station and an amount of interference to be simultaneously received in a section receiving the corresponding symbol. The determined Es/Io may be converted into a data transmission rate or a value corresponding thereto and transmitted to the base station in the form of a channel quality indicator (CQI), and be used for determining at what data transmission rate the base station will perform transmission to the UE.
In the case of the LTE-A system, the UE feeds back information on a downlink channel state to the base station so that the base station may use the information for downlink scheduling. That is, the UE measures a reference signal transmitted by the base station in the downlink and feeds back information extracted therefrom to the base station in the form defined in the LTE/LTE-A standard. As described above, information fed back by the UE in LTE/LTE-A may be referred to as channel state information, and the channel state information may include the following three pieces of information.
The CQI may be replaced with a signal to interference plus noise ratio (SINR) that may be used similarly to the maximum data rate, maximum error correction code rate and modulation scheme, and data efficiency per frequency.
The RI, PMI, and CQI are associated with each other and have meaning. For example, a precoding matrix supported by LTE/LTE-A is defined differently for each rank. Therefore, a PMI value X when the RI has a value of 1 and a PMI value X when the RI has a value of 2 may be interpreted differently. Further, even when the UE determines a CQI, it is assumed that the PMI and X notified by the UE to the BS are applied by the BS. That is, when the UE reports RI_X, PMI_Y, and CQI_Z to the base station, it is equivalent to reporting that the corresponding UE may receive a data rate corresponding to CQI_Z when the rank is RI_X and the PMI is PMI_Y. In this way, when the UE calculates the CQI, it is assumed which transmission method will be performed by the base station so that an optimized performance may be obtained when actual transmission is performed using the corresponding transmission method.
The RI, PMI, and CQI, which are channel state information fed back by the UE in LTE/LTE-A, may be fed back in a periodic or aperiodic form. In the case that the base station wants to aperiodically acquire channel state information of a specific UE, the base station may be configured to perform aperiodic feedback (or aperiodic channel state information reporting) using an aperiodic feedback indicator (or channel state information request field, channel state information request information) included in downlink control information (DCI) for the UE. Further, when the UE receives an indicator configured to perform aperiodic feedback in an nth subframe, the UE includes aperiodic feedback information (or channel state information) in data transmission in an n+kth subframe to perform uplink transmission. Here, k is a parameter defined in the 3GPP LTE Release 11 standard, is 4 in frequency division duplexing (FDD), and may be defined as illustrated in [Table 8] in time division duplexing (TDD).
In the case that aperiodic feedback is configured, feedback information (or channel state information) includes an RI, PMI, and CQI, and the RI and PMI may not be fed back according to a feedback configuration (or channel state report configuration).
An in-band full duplex (hereinafter, referred to as full duplex) system is a system in which an uplink signal and a downlink signal of the same cell are simultaneously transmitted within the same band and time resource, unlike a time division transmission and reception (TDD) or frequency division transmission and reception (FDD) system. That is, in the full duplex system, uplink and downlink signals are mixed in the same cell and exist, which acts as interference.
A type of additional interference caused by the use of a full duplex system may be classified into two types: self-interference and cross-link interference.
Self-interference means interference received (or generated) from downlink transmission of the base station in the same band when the base station receives uplink of the UE and/or interference received (or generated) from uplink transmission of a UE when the UE receives downlink in the case that the UE has a full duplex operation function. Self-interference greatly reduces a signal to interference and noise ratio (SINR) of a desired signal because transmission and reception occur at a shorter distance than the desired signal. Therefore, a transmission performance of a full duplex system is greatly affected by a performance of self-interference cancellation technology.
Cross-link interference means interference received from downlink transmission of other base stations received in the same band when a base station receives uplink of a UE and/or interference received from uplink transmissions of other UEs when a UE receives downlink. In the case of cross-link interference in which a base station receiving an uplink signal receives from downlink transmission of another base station, a distance from an interference transmitting end to an interference receiving end is greater than a distance between the UE transmitting a request signal of the base station and a receiving end of the base station, but because interference transmission power is generally greater than transmission power of the UE by 10-20 dB, it may greatly affect a reception SINR performance of an uplink desired signal of the UE received by the base station. Further, a UE receiving downlink may receive cross-link interference from another UE using uplink in the same band. In this case, in the case that a distance between a UE causing the interference and a UE receiving the downlink is meaningfully closer than the distance between the base station and the UE receiving the downlink, a downlink desired signal reception SINR performance of the UE may be lowered. In this case, the meaningfully close case means a close state in which reception power of interference coming from the uplink UE in the downlink receiving UE is greater than or similar to the received signal from the base station in the downlink receiving UE; thus, a performance of the downlink reception SINR of the UE may be lowered.
In a cellular-based mobile communication system, a type of a full duplex system is divided into a type in which only the base station supports self-interference cancellation for supporting a full duplex operation and a type in which both the base station and the UE support self-interference cancellation for supporting a full duplex operation. The reason for not considering the case that only the UE has self-interference cancellation is that antenna separation self-interference cancellation, RF-circuit self-interference cancellation, and digital self-interference cancellation, which are components may be implemented more easily in the base station than in the UE in terms of a form factor size and a circuit structure. The type of the full duplex system considered in various embodiments of the disclosure basically considers the case in which the base station has self-interference cancellation for convenience of description, but various embodiments of the disclosure may be equally applied and to not only the case that only the base station has self-interference cancellation, but also the case that both the UE and the base station have self-interference cancellation. In various embodiments of the disclosure, for convenience of description, an operation for self-interference measurement of an IAB node as an example of the base station will be described. However, the embodiment of the disclosure may be equally applied to other base stations for measuring self-interference as well as the IAB node. For example, the base station other than the IAB node may receive a configuration for self-interference channel measurement from a higher node or a third base station, and the other base station may transmit a signal for self-interference measurement in a resource indicated by the self-interference channel measurement configuration, and measure the self-interference channel based on the signal.
In
With reference to
The integrated access backhaul (IAB) network is a network capable of improving network densification caused by physical limitations of a wired backhaul and extending the network to particularly, a high-frequency band area. Base stations communicate with UEs over radio access links. One base station (IAB-donor) is connected to a fiber optic backhaul link, and other base stations (IAB-nodes) communicate wirelessly with the IAB-donor or perform wireless communication between IAB-nodes. Among the IAB-nodes wirelessly connected to the backhaul link, a higher-level IAB-node close to the IAB-donor becomes a parent IAB or an upper-level IAB, and a lower-level IAB close to the UE becomes a child IAB or a lower IAB. At least one base station directly communicating with the core network may function as a root node. An IAB-node connected by a wireless backhaul link may wirelessly communicate with one or more other IAB-node nodes, exchange information, and function as an anchor for communicating with the core network. In various embodiments of the disclosure, it is assumed and described that the IAB-node of the integrated access backhaul network is a base station operating in a full duplex system.
With reference to
With reference to
Even in the case that the IAB-node 806 does not receive downlink scheduling from the IAB-donor 800 to the IAB-MT 804, it is impossible to distinguish whether the time-frequency resource used for DU-to-MT self-interference measurement is in use by the IAB-donor 800. That is, in the time-frequency resource used by the IAB-node 806 in order to measure DU-to-MT self-interference, the case that the IAB-donor 800 transmits downlink to an MT or UE of another IAB-node may not be recognized. In this case, a signal transmitted from the IAB-donor 800 to the MT of another IAB-node acts as an interference signal in the DU-to-MT self-interference channel measured by the IAB-node 806; thus, the IAB-node 806 may inaccurately measure the self-interference channel.
In various embodiments of the disclosure, the IAB-donor 800 may transmit or exchange information for measuring an interference channel to or with the IAB-node 806. The IAB-donor 800 may transmit information including at least one of an uplink and downlink transmission time-frequency resource or a self-interference measurement indicator to the IAB-node 806, and the IAB-node 806 may measure DU-to-MT self-interference using a designated resource. In this case, the IAB-donor 800 may lower a level of an interference signal generating in DU-to-MT self-interference measurement of the IAB-node 806 with a method of not using the corresponding resource or transmitting the corresponding resource by lowering transmission power.
According to various embodiments of the disclosure, information for self-interference measurement of an IAB-node may be exchanged between an IAB-donor and an IAB-node through RRC, medium access control (MAC) control element (CE), or DCI.
With reference to
With reference to
When it is determined that self-interference measurement is necessary other than the case that a self-interference measurement configuration is designated by the IAB-donor 1004, the IAB-node 1002 may transmit information for an SI measurement indication request to the IAB-donor 1004 (1022). For example, in the case that a new UE is introduced into the coverage of the IAB-node 1002, in the case that a beam transmitting to a UE 1000 is changed, or in the case that a received packet decoding failure rate is a threshold or more, the IAB-node 1002 may transmit information for a self-interference measurement indication request to the IAB-donor 1004. The information or message for the self-interference measurement indication request may include at least one information of a time resource or a frequency resource to measure self-interference, a self-interference measurement indication, a self-interference measurement period, or a self-interference measurement beam configuration (1022). To this end, information on resources that may be requested by the IAB-node 1002 may be configured in advance or may be received in advance from the IAB-donor 1004. The frequency resource may be a frequency resource in which self-interference is estimated to occur. In response to the self-interference measurement indication request message from the IAB-node 1002, the IAB-donor 1004 may transmit a message including either information indicating specific information among information transferred to the self-interference channel measurement configuration through an RRC message, or at least one information of a time resource or a frequency resource to measure newly configured self-interference, self-interference measurement indication, or approval indication for all or part of information simply requested by the IAB-node 1002 to the IAB-node 1002 (1024). Further, the IAB-node 1002 may provide interference measurement information to the IAB-donor 1004, and the IAB-donor 1004 may provide a self-interference measurement configuration to the IAB-node 1002 based on interference measurement information.
By not using the time-frequency resource indicated through operation 1020 or 1024 (e.g., uses ZP-CSI-RS), lowering and using transmission power of the resource, or not using a beam that causes interference of a threshold or more for the IAB-node, the IAB-donor 1004 may lower a level of an interference signal generated in self-interference measurement of the IAB-node 1002 (1042).
The IAB-node 1002 measures a signal received to the IAB-MT to measure (1040) a DU-to-MT self-interference channel while transmitting (1026) a signal to the time-frequency resource for self-interference channel measurement. For example, while transmitting a downlink signal through an IAB-DU of the IAB-node 1002, the IAB-node 1002 may measure a signal received to the IAB-MT thereof to measure the DU-to-MT self-interference channel. Alternatively, a signal transmitted by the IAB-DU of the IAB-node 1002 may use a pre-defined signal or may use a control signal or data signal transmitted to downlink of the UE. The IAB-node 1002 may transmit an arbitrary signal to a corresponding resource for DU-to-MT self-interference measurement even in the case that there is no UE to transmit downlink. A resource to which a signal is transmitted may be any resource in which the IAB-node 1002 may configure as well as reference signal resources such as CSI-RS, DM-RS, and CRS commonly used for channel measurement. For example, the IAB-MT may measure a self-interference channel from all or part of an SSB, PDCCH, or PDSCH resource transmitted by the IAB-DU. This is because the IAB-MT accurately knows a signal transmitted by the IAB-DU within the same IAB-node 1002.
Further, the IAB-node 1002 may separately measure a self-interference channel for each subset of beams belonging to a beam set operating in each self-interference measurement resource. For example, the IAB-node 1002 may measure a self-interference channel for a beam communicating with the UE 1000, measure self-interference for each beam while sweeping all or part of all beams in operation, or measure self-interference for any beam.
Some of information included in the self-interference channel measurement configuration may be configured as an RRC message, and some information may be configured through an MAC CE or DCI. Further, in the case that at least one information of the self-interference channel measurement configuration is configured through an RRC message and that a specific event occurs in the IAB-node 1002, self-interference may be measured using the preconfigured information. Further, at least one information of self-interference channel measurement configuration may be configured through an RRC message and indicate self-interference channel measurement or trigger through an MAC CE or DCI.
The message described in the embodiment of
With reference to
In a multi-hop IAB structure, a lower IAB node 1102 receives (1126) self-interference channel measurement configuration information from an upper IAB node 1104. In this case, the self-interference channel measurement configuration information 1126 may be information generated by the upper IAB node 1104 or may be part or all of self-interference measurement information 1120 received by the upper IAB node 1104 from an IAB-donor 1106. Further, information 1122 requesting a self-interference measurement indication transmitted from the higher IAB-node 1104 to the IAB-donor 1106 may include part or all of self-interference measurement indication request information 1128 transmitted from the lower IAB-node 1102 to the higher IAB-node 1104. Further, a self-interference measurement indication message 1130 transmitted from the upper IAB-node 1104 to the lower IAB-node 1102 may include all or part of a self-interference measurement indication message 1124 received by the upper IAB-node 1104 from the IAB-donor 1106. In this case, message transmission and reception may be performed in the order of operation 1128, operation 1122, operation 1124, and operation 1130.
After the upper IAB-node 1104 configures self-interference measurement resources of the lower IAB-node 1102, the upper IAB-node 1104 may transmit a message including the corresponding configuration information to the IAB-donor 1106 (1132). This is for the IAB-donor 1106 to perform (1140) a ZP-CSI-RS related operation or a muting operation for preventing interference in self-interference measurement resources of the lower IAB-node 1102. Further, in operation 1139, the IAB-donor 1106 may perform a ZPI-CSI-RS related operation or a muting operation for preventing interference in self-interference measurement resources of the upper IAB-node 1104. In operation 1135, the upper IAB node 1104 may perform a DU-to-MT self-interference channel measurement operation. In order to perform operation 1135, the self-interference transmission operation 1134 may be transmission to the lower IAB node 1102 or SI transmission to a UE 1100 or another UE.
In operation 1141, the higher IAB node 1104 may perform a ZP-CSI-RS related operation or a muting operation for preventing interference in self-interference measurement resources of the lower IAB node 1102. The upper IAB-node 1104 may perform operation 1141 based on a message received from the lower IAB-node 1102 in operation 1128 or a message received from the IAB-donor 1106 in operation 1124.
In operation 1143, the lower IAB node 1102 may transmit a signal for measuring the self-interference channel, and in operation 1145, the lower IAB node 1102 may perform a self-interference channel measurement operation. Self-interference may correspond to DU-to-MT self-interference channel measurement.
With reference to
In order to efficiently schedule self-interference measurement of the plurality of IAB-nodes, the IAB-donor 1202 may cluster a plurality of IAB-nodes to transmit a self-interference measurement indication message or a resource muting message. The clustering unit may be an IAB-node unit, a beam unit, or an IAB-node-UE pair unit.
With reference to
The IAB-node 1304 may provide a self-interference channel measurement announcement set including a plurality of self-interference channel measurement announcements to other IAB-nodes 1300 and 1302. The other IAB-nodes 1300 and 1302 may transmit permission messages for all or part of the plurality of self-interference channel measurement announcements.
The IAB-node 1304 may perform self-interference channel measurement (1340) based on permission messages received from other IAB-nodes or may transmit a new self-interference channel measurement announcement.
As described with reference to
In operation 1420, the first node may transmit a measurement signal for measuring self-interference based on the self-interference channel measurement configuration. For example, the self-interference channel measurement configuration may include information such as a type and index of the measurement signal, and include information on a resource to transmit the measurement signal. The measurement signal may be a reference signal such as a CSI-RS, CRS, or DMRS, a synchronization signal such as an SSB, or a signal, information, or data transmitted by an IAB-node to a UE through a PDCCH or PDSCH. Further, the IAB node may classify a beam set in operation in an interference measurement resource acquired through the self-interference measurement configuration into each beam subset to measure the interference channel.
The second node or higher IAB node that has transmitted the self-interference channel measurement configuration for the interference channel measurement operation may not transmit a signal in the resource for measuring the interference channel or may transmit a signal in a low level that does not interfere with the IAB node.
In operation 1430, the first node may measure the self-interference generated by the measurement signal for measuring the self-interference channel based on the self-interference channel measurement configuration. A resource for measuring self-interference and a resource for transmitting a measurement signal may be the same or partially overlap each other.
In operation 1440, the IAB node may transmit a first signal and receive a second signal. The first signal and the second signal may be performed in the same time resource and frequency resource or may be performed in partially overlapped resources. The first signal transmitted by the IAB node may act as interference with respect to the second signal received by the IAB node.
In operation 1450, the IAB node may cancel self-interference with respect to the second signal. For example, the IAB node may cancel self-interference by the first signal based on self-interference channel measurement.
With reference to
The transceiver 1510 may transmit and receive signals to and from a base station 1540. Here, the signal may include control information and data. To this end, the transceiver 1510 may include an RF transmitter for up-converting and amplifying a frequency of a signal to be transmitted, and an RF receiver for amplifying a received signal with low noise and down-converting a frequency thereof. However, this is only an embodiment of the transceiver 1510, and the components of the transceiver 1510 are not limited to the RF transmitter and the RF receiver. Further, the transceiver 1510 may receive a signal through a wireless channel, output the signal to the controller 1520, and transmit the signal output from the controller 1520 through the wireless channel. Further, the transceiver 1510 may separately include an RF transceiver for first wireless communication technology and an RF transceiver for second wireless communication technology or may perform physical layer processing with a single transceiver according to the first wireless communication technology and the second wireless communication technology.
The storage 1530 may store programs and data necessary for operation of the UE 1500. Further, the storage 1530 may store control information or data included in signals transmitted and received by the UE 1500. The storage 1530 may include a storage medium such as a read only memory (ROM), a random access memory (RAM), a hard disk, a compact disk read only memory (CD-ROM), and a digital versatile disc (DVD), or a combination of storage media. Further, the storage 1530 may be the plural.
The controller 1520 may control a series of processes so that the UE 1500 may operate according to the above-described embodiment of the disclosure. For example, the controller 1520 may transmit and receive data to and from the base station or other UEs based on resource allocation information received from the base station 1540 through the transceiver 1510. The controller 1520 may be the plural, and the controller 1520 may execute a program stored in the storage 1530 to perform a component control operation of the UE 1500. The controller 1520 may include at least one processor.
The base station 1540 may include a transceiver 1550, a controller 1560, a connection unit 1570, and a storage 1580. However, the components of the base station 1540 are not limited to the above-described examples, and for example, the base station 1540 may include more or fewer components than the illustrated components. Further, the transceiver 1550, the storage 1580, and the controller 1560 may be implemented in a single chip form. The base station 1540 may correspond to an IAB-donor, an upper IAB node, or a lower IAB node according to various embodiments of the disclosure.
The transceiver 1550 may transmit and receive signals to and from the UE 1500. Here, the signal may include control information and data. To this end, the transceiver 1550 may include an RF transmitter for up-converting and amplifying a frequency of a signal to be transmitted, and an RF receiver for amplifying a received signal with low noise and down-converting a frequency thereof. However, this is only an embodiment of the transceiver 1550, and the components of the transceiver 1550 are not limited to the RF transmitter and the RF receiver. Further, the transceiver 1550 may receive a signal through a wireless channel, output the signal to the controller 1560, and transmit the signal output from the controller 1560 through a wireless channel.
The controller 1560 may control a series of processes so that the base station 1540 may operate according to the above-described embodiment of the disclosure. For example, the controller 1560 may generate a message to be transmitted to another base station and transmit the message to the other base station through the connection unit 1570. The controller 1560 may be the plural, and the controller 1560 may execute a program stored in the storage 1580 to perform a component control operation of the base station 1540. Further, the controller 1560 may include a DSM.
The storage 1580 may store programs and data necessary for the operation of the base station. Further, the storage 1580 may store control information or data included in signals transmitted and received by the base station. The storage 1580 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Further, the storage 1540 may be the plural.
The connection unit 1570 is a device that connects the base station 1540 with the core network and other base stations, and may perform physical layer processing for message transmission and reception, and operations for transmitting messages to other base stations and receiving messages from other base stations.
Embodiments of the disclosure disclosed in this specification and drawings merely present specific examples in order to easily describe the technical contents of the disclosure and to help the understanding of the disclosure, and they are not intended to limit the scope of the disclosure. That is, it will be apparent to those of ordinary skill in the art to which the disclosure pertains that other modifications based on the technical spirit of the disclosure may be implemented. Further, each of the above embodiments may be operated in combination with each other, as needed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0114128 | Sep 2020 | KR | national |
| 10-2021-0004524 | Jan 2021 | KR | national |
This application is a 371 National Stage of International Application No. PCT/KR2021/008636, filed Jul. 7, 2021, which claims priority to Korean Patent Application No. filed Sep. 7, 2020, and Korean Patent Application No. 10-2021-0004524, filed Jan. 13, 2021, the disclosures of which are herein incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2021/008636 | 7/7/2021 | WO |
