Abstract: A modular hardware platform utilizes a combination of different types of units that are pluggable into cassette endpoints. The present disclosure enables the construction of an extremely large system, e.g., 500 Tb/s+, as well as small, standalone systems using the same hardware units. This provides flexibility to build different systems with different slot pitches. The hardware platform includes various numbers of stackable units that mate with a cost-effective, hybrid Printed Circuit Board (PCB)/Twinax backplane, that is orthogonally oriented relative to the stackable units. In an embodiment, the hardware platform supports a range of 14.4 Tb/s-800 Tb/s+ in one or more 19? racks, providing full features Layer 3 to Layer 0 support, i.e., protocol support for both a transit core router and full feature edge router including Layer 2/Layer 3 Virtual Private Networks (VPNs), Dense Wave Division Multiplexed (DWDM) optics, and the like.

Abstract: A plug-in network device is disclosed. The plug-in network device can be used in association with a network management system and an infrastructure network device. The plug-in network device includes two antenna arrays, one of which is up-facing and one of which is front-facing. The plug-in network device can achieve wireless communication with the infrastructure network device via the up-facing antenna array and provide network services to wireless stations through the front-facing antenna array. The network management system can manage both the infrastructure network device and the plug-in network device.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit a negative acknowledgment (NACK) associated with a downlink communication, and may transmit a channel state information (CSI) report based at least in part on transmitting the NACK associated with the downlink communication. In some aspects, a base station may receive, from a UE, a NACK associated with a downlink communication, and may monitor for the CSI report based at least in part on receiving the NACK. Numerous other aspects are provided.

Abstract: In some embodiments, a phased array antenna includes a carrier; a first plurality of antenna elements carried by the carrier and configured to transmit and/or receive signals at a first value of a parameter, and a second plurality of antenna elements carried by the carrier and configured to transmit and/or receive signals at a second value of the parameter different from the first value of the parameter. The antenna elements of the first plurality of antenna elements and the second plurality of antenna elements are located within a common aperture of the phased array antenna.

Abstract: An embodiment method of network node operation includes indicating, by a first network node, to a first UE, a first number of REs in a first set of RBs for a first reference signal, transmitting, by the first network node, to the first UE, the first reference signal in accordance with the first number of REs and a first precoding in a first subframe, receiving, by the first network node, from the first UE, a report indicating a first MCS in accordance with a level of signal and interference measured by the first UE, wherein the measurement is restricted to the first reference signal, and transmitting, by the first network node, a first data with the indicated first MCS and the first precoding in a second subframe, the first data being transmitted on a second number of REs in the first set of RBs in the second subframe.

Abstract: [Problem] An optical receiver using a polarization demultiplexing technique is miniaturized. [Solution] An optical receiver 100A for receiving a polarization multiplexed signal obtained by performing orthogonal polarization multiplexing on two optical signals.

Abstract: During operation, a radio node may determine a desired bandwidth in a shared-license-access band of frequencies. Then, the radio node may identify two or more sub-spectra based at least in part on the desired bandwidth, where a sum of ranges of frequencies in the sub-spectra equals the desired bandwidth, and a given sub-spectra includes a range of frequencies. Next, the radio node may provide, to the computer, grant requests for the sub-spectra, where a given grant request includes a request to reserve a given one of the sub-spectra for use by the radio node, and a probability of approval of the given grant request is larger than a probability of a grant request for the desired bandwidth. Note that at least two of the sub-spectra may be separated by an intervening band of frequencies (i.e., at least two of the sub-spectra may be non-contiguous).

Abstract: A base station and terminal use methods of obtaining synchronization and system information in a wireless communication system. An operation of a base station includes generating a synchronization signal to be transmitted through a Synchronization Channel (SCH), generating a broadcast signal to be transmitted through a Broadcast Channel (BCH), and transmitting repetitively the SCH and the BCH by performing beamforming on the channels with different transmission beams.

Abstract: An antenna includes a first portion and a second portion. The first portion is of a first shape and the second portion is of a second shape. The second portion is connected to the first portion by a junction. The antenna operates in a first frequency band and a second frequency band.

Abstract: Power management for remote units in a wireless distribution system. Power can be managed for a remote unit configured to power modules and devices that may require more power to operate than power available to the remote unit. For example, the remote unit may be configured to include power-consuming remote unit modules to provide communication services. As another example, the remote unit may be configured to provide power through powered ports in the remote unit to power-consuming devices. Depending on the configuration of the remote unit, the power-consuming remote unit modules and/or power-consuming devices may demand more power than is available at the remote unit. In this instance, the power available at the remote unit can be distributed to the power-consuming modules and devices based on the priority of services desired to be provided by the remote unit.

Abstract: Techniques for determining an angle-of-arrival of a wireless transmission are provided, including receiving, with a first antenna, at least a first portion of a wireless transmission, determining when a second portion of the wireless transmission will be received, switching to the second antenna to receive the second portion of the wireless transmission, determining an angle of arrival of the wireless transmission based on the first portion and the second portion of the wireless transmission, and outputting the angle of arrival of the wireless transmission.

Abstract: The present application provides a method for calibrating a transmitter. The transmitter includes an oscillator, a first signal path, and a second signal path. The first signal path and the second signal path include a first calibration unit preceding a first low pass filter and a second low pass filter, and a second calibration unit succeeding the first low pass filter and the second low pass filter. The calibration method includes: by configuring the first calibration unit and the second calibration unit and sending a transmission signal, and performing frequency analysis upon the transmission signal to obtain a frequency analysis result, to generate an optimized first compensation value for the first calibration unit and an optimized second compensation value for the second calibration unit.

Abstract: A method for communications is disclosed. The method includes determining, at a terminal device, status information of at least one of a first frequency band and a second frequency band. The terminal device is operable in the first frequency band and the second frequency band. The method further includes performing an allocation of multiple antennas of the terminal device between the first frequency band and the second frequency band, based at least in part on the status information.

Abstract: This document discloses a solution for computing beamforming coefficients for a radio channel between two apparatuses. According to an aspect, a method comprises: obtaining a channel matrix representing a radio channel between an apparatus and another apparatus; obtaining an initial eigenvector estimate for an eigenvector of the channel matrix; computing an intermediate eigenvector estimate based on the channel matrix and the initial eigenvector estimate; computing an error vector representing an error between the initial eigenvector estimate and the intermediate eigenvector estimate; computing a final eigenvector estimate based on the error vector and the intermediate eigenvector estimate; and determining beamforming coefficients based on the final eigenvector estimate and communicating with said another apparatus by using the beamforming coefficients.

Abstract: A system having an array of antennas with particular weights for signals associated with different groups of antennas. The array of antennas includes a first group of antennas positioned in a middle portion of the array of antennas, a second group of antennas positions at one or more edges of the array of antennas, and a third group of antennas positioned at one or more corners of the array of antennas. The system includes a control module configured to control each respective and tenant in the array of antennas. The control module can further be configured to weight the first group of antennas a first weighting amount, to weight the second group of antennas a second weighting amount and to weight the third group of antennas a third weighting amount. The weighting improves the system's ability to reduce ambiguities in an angle of arrival associated with the object.

Abstract: Distributed antenna systems provide location information for client devices communicating with remote antenna units. The location information can be used to determine the location of the client devices relative to the remote antenna unit(s) with which the client devices are communicating. A location processing unit (LPU) includes a control system configured to receive uplink radio frequency (RF) signals communicated by client devices and determines the signal strengths of the uplink RF signals. The control system also determines which antenna unit is receiving uplink RF signals from the device having the greatest signal strength.

Abstract: Systems, methods, apparatuses, and computer program products for array antenna adaptive digital pre-distortion with Bayesian observation analysis are provided. One method may include selecting a plurality of patch elements from an array antenna of a network element. The method may also include determining an accuracy confidence value for each patch element. A set of coefficients of the antenna array may be generated. In addition, an ensemble of non-linear forward models may be generated using the accuracy confidence value and the set of coefficients. Further, an array of pre-distortion signals may be generated using the ensemble of non-linear forward models, and each antenna of the array antenna may be configured with a corresponding pre-distortion signal from the array of pre-distortion signals.

Abstract: Device, methods and systems for aspects of channel estimation for orthogonal time frequency space (OTFS) modulation in wireless systems are described. In an aspect, a method for wireless communication may include receiving, using multiple receive antennas, from a number of user devices, non-orthogonal pilots wherein at least some transmissions of the non-orthogonal pilots from different user devices overlap in at least some time and frequency resources, estimating individual pilots from the number of user devices by computing a pilot separation filter for each antenna, and estimating the wireless channel at time and frequency resources used by the non-orthogonal pilots by filtering the receiving signal at the multiple receiver antennas.

Abstract: A communication apparatus capable of wireless communication with another communication apparatus via a first communication path and a second communication path sets a directivity of an antenna to a first directivity capable of wireless communication via the first communication path and receives data from the another communication apparatus via the first communication path. When the communication apparatus sends an acknowledgement signal to the another communication apparatus via the first communication path in response to reception of the data, the communication apparatus sets the directivity of the antenna to a second directivity capable of wireless communication via the first communication path and wireless communication via the second communication path for a set period thereafter.

Abstract: A base station includes: a communication circuit configured to communicate with a mobile station; a prediction circuit configured to predict a period during which communication with the mobile station is blocked; and a controller configured to control the communication circuit in such a way that communication data to be transmitted to the mobile station in the period during which communication is blocked are transmitted in a period before the period during which communication is blocked.

Abstract: There is provided mechanisms for transmission of synchronization signals. A method is performed by a network node. The method comprises transmitting polarized bursts of SSB in beams. One SSB is transmitted per each beam in each burst. Polarization of at least one of the SSBs changes between two consecutive bursts of the SSBs.

Abstract: When spatial quasi co-location is established between component carriers, beam management, e.g., beam configuration or reference signal configuration, of one component carrier may be performed based at least in part on beam management information of the other. Information specifying that component carriers or reference signals cross component carriers are spatially quasi co-located, or information about a SQCL group including spatially quasi co-located carriers, may be transmitted to a UE, e.g., using broadcast signaling, radio resource control (RRC) signaling, a media access control-control element (MAC-CE), downlink control information (DCI) signaling, or a combination thereof.

Abstract: Certain disclosed methods include: transmitting an excitation signal into the MUT and transmitting a reference signal to a set of magnitude and phase (M/P) detectors; receiving the response signal; separately comparing a magnitude and phase for each of the excitation signal and the reference signal with corresponding detection ranges for a first one of the M/P detectors; separately comparing a magnitude and phase for each of the response signal and the reference signal with corresponding detection ranges for a second one of the M/P detectors; iteratively adjusting the excitation signal until the response signal has both a magnitude and a phase within the corresponding detection ranges for the second M/P detector; and iteratively adjusting the reference signal until the reference signal has both a magnitude and a phase within the corresponding detection ranges for the first and the second M/P detectors.

Abstract: Provided are an array antenna apparatus using spatial power spectrum combining and a method of controlling the same. The array antenna apparatus includes a uniform linear array antenna module including antennas which are uniformly and linearly arranged, an array antenna determiner configured to select sub-array antennas arranged at a first distance and sub-array antennas arranged at a second distance from the array antennas in the uniform linear array antenna module in order to derive spatial spectrum components from the uniform linear array antenna module, a spatial spectrum component deriver configured to separately derive spatial power spectrum components from signals received through the selected sub-array antennas selected by the array antenna determiner, and an azimuth calculator configured to calculate an azimuth by performing a calculation with a first spatial spectrum component and a second spatial spectrum component which are separately derived.

Abstract: A method employing an array of antenna elements and a plurality of transceivers, each including (1) a transmitter chain; (2) a receiver chain; and (3) a duplexer having an input electrically connected to the transmitter chain, an output electrically connected to the receiver chain, and a duplexed port electrically connected to a different antenna element, the method involving: identifying among the plurality of transceivers a first and second subsets of transceivers such that together the first and second subsets of transceivers constitute all of the transceivers among the plurality of transceivers; for each transceiver within the first subset of transceivers, but not for the transceivers within the second subset of transceivers, introducing a ? degree phase shift between the duplexed port of the duplexer and the antenna element to which the duplexed port is electrically connected, wherein ?=?(2n+1)90°, and wherein n is an integer.

Abstract: A technique is provided for controlling a beam pattern employed by an antenna apparatus. The antenna apparatus comprises an antenna array, and beamforming circuitry to employ a beam pattern in order to generate a beam using the antenna array to facilitate wireless communication with at least one further antenna apparatus. Beam pattern adjustment circuitry is then arranged to receive a control signal indicative of a motion being imparted to the antenna apparatus, and to adjust the beam pattern to be used by the beamforming circuitry in dependence on the control signal, so as to alter a width of the beam in order to mitigate variation in link quality of the wireless communication due to the motion.

Abstract: A mobile station control method by a computer for controlling a first mobile station for communicating with a second mobile station includes: distance detecting of detecting a distance between the first mobile station and the second mobile station; and first switching of switching a beam width of an electromagnetic wave emitted from the first mobile station to the second mobile station switching a beam width of an electromagnetic wave emitted from the first mobile station to the second mobile station the distance.

Abstract: Systems and methods for determining a location of a mobile computing device requesting emergency services are provided. A mobile computing device may receive an indication of a request for emergency services from a user of the mobile computing device. The mobile computing device may receive a first wireless signal from a first device. The wireless signal may include an indication of a first geographic position associated with the first device. The mobile computing device may determine a location associated with the mobile computing device based on the indication of the first geographic position associated with the first device, and may send the determined location to a provider of emergency services.

Abstract: Methods, devices and computer programs for determining new transmit directions to use for beamformed transmissions in case the link quality of an existing direction falters. A transmitting communication device and a receiving communication device cooperate via a beam tracking procedure to determine a new suitable transmit direction to use for upcoming beamformed transmissions. Information relating to the beam tracking procedure is communicated over an existing link that enables communication between the transmitting and receiving communication devices. The receiving communication device provides the transmitting communication device with information about a beam scan performed in order to detect tracking beams transmitted by the transmitting communication device. This information allows the transmitting communication device to determine suitable transmit directions to use.

Abstract: The systems and methods described herein support efficient SDM operation in IAB networks. A first node receives a semi-static resource allocation from a CU based on at least one multiplexing capability of the first node. The first node also receives from the CU one or more resource conditions for using allocated resources of the semi-static resource allocation, and the first node communicates with a second node based on the semi-static resource allocation and the one or more resource conditions. The at least one multiplexing capability includes at least one of SDM or FDM, including full duplex or half duplex. The at least one multiplexing capability is also with respect to one or more transmission direction combinations of the first node.

Abstract: A wireless device receives: a first maximum total transmit power allowed for a first cell group of a first type of radio access technology; and a second maximum total transmit power allowed for a second cell group of a second type of radio access technology. It is determined that a total transmission power exceeds a value based on: a first power for transmission of first uplink signal(s) via the first cell group, and a second power for transmission of second uplink signal(s) via the second cell group. The first and second powers are less than or equal to the first and second maximum total transmit powers respectively. Scheduled transmission of the first uplink signal(s) of the first cell group is dropped in response to the first cell group being of the first type of radio access technology. Second uplink signal(s) are transmitted to a base station.

Abstract: The technologies described herein are generally directed to modeling radio wave propagation in a fifth generation (5G) network or other next generation networks. For example, a method described herein can include, for a network application, identifying, by a system comprising a processor, a user equipment communicatively coupled to base station equipment via a first network connection implementing a first radio access technology and a second network connection implementing a second radio access technology. The method can further include identifying, by the system, performance characteristics of the first network connection and the second network connection. Further, the method can include, based on the first performance characteristic and the second performance characteristic, facilitating, by the system, allocating, to the user equipment, power for uplink transmission by the first network connection and the second network connection, resulting in an uplink power allocation.

Abstract: An apparatus performs a discrete Fourier transform process on M×N received signal components included in a received signal, by a unit of N received signal components; and estimates an estimated signal containing M×N estimated signal components, which are estimated values of M×N transmission signal components, on the basis of the received signal on which the discrete Fourier transform process is performed. When the estimated signal xe is newly estimated, the apparatus performs an exclusion operation of excluding an estimated value xe(k) of the M transmission signal components that constitute a k-th transmission signal group from the estimated signal xe newly estimated, and updates the estimated value xe(k) based on an intermediate signal xt(k) obtained by the exclusion operation and the received signal, thereby re-estimating the estimated signal xe.

Abstract: A transmitter in a wireless communication network comprises a Carrier Interferometry (CI) coder and a multicarrier modulator communicatively coupled to the CI coder. The CI coder encodes a plurality of data symbols with a plurality of CI codes to produce a plurality of CI symbol values, wherein each of the plurality of CI symbol values equals a sum of information-modulated CI code chips. Each information-modulated CI code chip equals a CI code chip multiplied by one of the plurality of data symbols. The modulator modulates each CI symbol value onto a different subcarrier frequency to produce a multicarrier signal.

Abstract: To prevent un-authorized accesses to data and resources available in workloads on an organization's or enterprise's computer network, various improvements to automated computer network security processes to enable them to enforce network security policies using native network security mechanisms to control communications to and/or from workload units of applications running on different nodes within hybrid computer network infrastructures having both traditional hardware resources and virtual resources provided by private and public cloud infrastructure services.

Abstract: A technique includes sending, by a relay node to a candidate base station via a base station-to-base station connection, a request for transmission of reference signals, wherein the base station-to-base station connection includes, at least in part, a wireless connection; receiving, by the relay node from the candidate base station, a reference signal configuration; and measuring one or more signal parameters of one or more received reference signals based on the received reference signal configuration.

Abstract: A signal processing device includes: a first subarray that includes power amplifiers and phase shifters and that forms a first beam facing in a first direction; a second subarray that includes power amplifiers and phase shifters and that forms a second beam facing in a second direction; a feedback unit that feeds back at least signals that are output from the power amplifiers included in the first subarray; and a processor that is connected to the first subarray and the second subarray. The processor executes a process including: generating, based on a first feedback signal and a transmission signal output to the first subarray, a cancellation signal corresponding to an interference component applied to the second beam by the first beam; and adding the generated cancellation signal to a transmission signal output to the second subarray.

Abstract: An active repeater device includes a primary sector and at least a secondary sector communicatively coupled to the primary sector receives or transmits a first beam of input RF signals having a first beam pattern from or to a base station, respectively. The primary sector includes an baseband signal processor and a first radio head (RH) unit. The secondary sector comprises a second RH unit. The first beam pattern covers a first geographical area. Beamforming coefficients are generated to convert the first beam pattern of the first beam of input RF signals to a second beam pattern. A second beam of output RF signals in the second beam pattern is transmitted from or received by, respectively, the secondary sector to or from, respectively, a plurality of user equipment (UEs) based on the generated beamforming coefficients and the received first beam of input RF signals.

Abstract: A positioning control method includes: determining a position of a positioning object; determining, based on the position of the positioning object, at least one target positioning beacon whose distance to the positioning object satisfies a predetermined condition; and sending a prompt message to the target positioning beacon, wherein the prompt message is intended to instruct a positioning beacon to switch a broadcast frequency from a first frequency to a second frequency which is greater than the first frequency.

Abstract: Beamforming for adapting wireless signaling beams in an adaptive and agile manner is contemplated. The beamforming may be characterized by adaptively constructing beam form parameters to provide wireless signaling in a manner that maximizes efficiency and bandwidth according to device positioning relative to a responding base station.

Abstract: A method for assisting the adaptation of a signal from a first node to a second node is provided. The first node communicates with the second node in a wireless communication system over a radio link. The second node has a codebook comprising a set of possible information alternatives for assisting the adaptation of a signal received from the first node. The second node may select an information alternative from the codebook and send it to the first node to assist the first node in adapting the signal. The first node is configured with a number of subsets, each comprising a part of the possible information alternatives. The first node requests that the second node restrict the selection of information alternatives to one of the subsets, and in response, receives an information alternative from the second node that is selected from among the subsets configured according to the configuration request.

Abstract: The present disclosure describes devices, systems, and methods for allocating bandwidth among communication links in a telecommunication system. Some aspects can involve identifying multiple transmission modes used to transmit downlink signals via remote units of a telecommunications system to groups of terminal devices. Each group of terminal devices may receive downlink signals using a respective transmission mode. Respective weights can be assigned to the groups of terminal devices based on the transmission modes. The downlink signals, which are provided to each remote unit associate with each group of terminal devices, can be configured using a respective signal power that is associated with a respective weight for the group of terminal devices associated with the respective remote unit.

Abstract: In a wireless communication terminal in a wireless communication system for performing a control not to transmit signals, or to transmit signals with a reduction in a transmission power by a part of radio resources for a downlink signal in a cell provided by a base station, the terminal receives control information in generating a report related to a measurement result of the cell provided by the base station, monitors a state of a radio link with an own cell, and performs measurement on reception of the downlink signal. If an instruction for restricting the measurement to a part of the radio resources is included in the control information from the base station after the radio link failure occurs, the terminal generates and transmits a radio link failure report including the measurement result in the radio resources as instructed when the radio link failure occurs.

Abstract: Certain aspects of the present disclosure provide techniques for selecting an uplink (UL) transmit beam by a user equipment (UE). A UE may receive, from a base station (BS), one or more beamformed downlink signals using one or more receive beams. The UE may select an uplink transmit beam based, at least in part, on the one or more beamformed downlink signals. The UE may transmit an uplink signal using the selected uplink transmit beam.

Abstract: Apparatus and methods for providing enhanced coverage in a quasi-licensed wireless system using a reduced-cost base station apparatus. In one embodiment, the base station is configured to utilize quasi-licensed 3.55-3.70 GHz CBRS (Citizens Broadband Radio Service) GAA and PAL spectrum, and employs a power amplifier sharing arrangement in its transmitter chain(s), along with multi-sector antenna elements. A scheduling algorithm operative on the base station generates sector-specific weights which are used to allocate the shared power amplifier(s) between the different sectors. Advantageously, design and production costs of the base station are reduced through sharing of comparatively expensive amplifier and transmitter chain components, thereby allowing for commoditization of the base station for mass distribution.

Abstract: A network node signals to a wireless communication device which precoders in a codebook are restricted from being used. The network node in this regard generates codebook subset restriction signaling that, for each of one or more groups of precoders, jointly restricts the precoders in the group by restricting a certain component (e.g., a certain beam precoder) that the precoders in the group have in common. This signaling may be for instance rank-agnostic signaling that jointly restricts the precoders in a group without regard to the precoders' transmission rank. Regardless, the network node sends the generated signaling to the wireless communication device.

Abstract: A wireless communication system which includes first and second wireless station apparatuses having a plurality of antenna elements and performs directivity forming. For T1 and T2 such that T2=N2×T0 and T1=N1×T2 with a predetermined period T0, the wireless communication system performs the steps of sequentially switching N1 types of directional beams at intervals of period T2 and transmitting signals while performing switching with an identical directional beam switching pattern maintained over period T1, sequentially switching N2 types of directional beams at intervals of period T0 and receiving signals over the period T1 or more while performing switching with an identical directional beam switching pattern maintained over the period T2, searching for a directional beam having a highest reception level among those acquired over a predetermined period, and setting the searched directional beam as a directional beam to be used.

Abstract: An active repeater device includes a primary sector and at least a secondary sector communicatively coupled to the primary sector receives or transmits a first beam of input RF signals having a first beam pattern from or to a base station, respectively. The primary sector includes an baseband signal processor and a first radio head (RH) unit. The secondary sector comprises a second RH unit. The first beam pattern covers a first geographical area. Beamforming coefficients are generated to convert the first beam pattern of the first beam of input RF signals to a second beam pattern. A second beam of output RF signals in the second beam pattern is transmitted from or received by, respectively, the secondary sector to or from, respectively, a plurality of user equipment (UEs) based on the generated beamforming coefficients and the received first beam of input RF signals.

Abstract: An electronic device, according to various embodiments of the present invention, is disclosed, comprising: an antenna array including a plurality of antenna elements disposed at intervals of a first distance; and a communication circuit electrically connected with the antenna array, wherein the communication circuit is configured to: supply power to a first antenna element and a second antenna element spaced apart from the first antenna element by a second distance among the plurality of antenna elements; form a beam comprising a main lobe and a grating lobe having a predetermined angle with the main lobe, by using the first antenna element and the second antenna element; and sense an RF signal incident from the outside by using the formed beam. Various other embodiments inferred from the present specification are also possible.

Abstract: The present invention provides a signal transmission method, a network device, a terminal device, and a communication system. The signal transmission method comprises: a network device sends a first synchronization signal of a first cell by using a first been, the first synchronization signal carrying identifier information of the first beam; the network device sends, by using the first beam, a first broadcast message scrambled by means of the identifier information of the first beam; a terminal device receives a first synchronization signal sent by the network device, and obtaining the identifier information of the first beam carried in the first synchronization signal; and the terminal device detects the first broadcast message according to the identifier information of the first beam. The signal transmission method, the network device, the terminal device and the communication system in the present invention, signal transmission quality can be improved.