Patent Publication Number: US-2023143144-A1

Title: Converged radio unit configured for semantic-less retransmissions

Description:
PRIORITY CLAIM 
     This application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 17/537,775, filed on Nov. 30, 2021, which claims priority under 35 USC 119 to U.S. Provisional Patent Application Ser. No. 63/127,398, filed Dec. 18, 2020 which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments pertain to wireless and radio-frequency (RF) communications. Some embodiments relate to RF repeaters. Some embodiments pertain to routers and network communications. Some embodiments pertain to semantic-less retransmissions. 
     BACKGROUND 
     The current state of the art for wireless repeaters and routers requires transmissions to be received and decoded by multiple network layers, including at least a physical layer (PHY) and a medium access control layer (MAC), and usually the network layer (NET), before being retransmitted. This results in highly complex routers especially for complex routing protocols. Another issue with current wireless repeaters and routers, besides complexity, is that they are generally configured for a limited number of routing protocols and operate for a limited number of waveforms. Yet another issue with current wireless repeaters and routers is preserving privacy since decoding is performed at the MAC and NET layers and possibly others. 
     Thus there are general needs for wireless repeaters and routers that are less complex, that are suitable for an unlimited number of routing protocols waveforms, and do not compromise privacy. 
     As defense network operations look to adopt 5G based high-throughput data links, finding a way to continue to support legacy tactical data links, which potentially are coexisting with the 5G system, becomes imperative. Doing so without needing to provide closely guarded credentials, typically used to forward and process data from these legacy systems, becomes especially valuable when considering the persons needed to guard any static deployments or remote sites. Thus, what is needed is a single device that can provide both zero-trust wireless network access and 5G connectivity that will simplify the deployments and lower the cost for customers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an RF repeater configured for semantic-less retransmissions in accordance with some embodiments. 
         FIG.  2    is a flow chart illustrating operations performed by an RF repeater configured for semantic-less retransmissions in accordance with some embodiments. 
         FIG.  3    illustrates a processing system in accordance with some embodiments. 
         FIG.  4    shows an I-Q sample region for use in determining whether or not to retransmit a received RF signal, in accordance with some embodiments. 
         FIG.  5    is a functional block diagram of a converged radio unit (RU), in accordance with some embodiments. 
         FIG.  6    illustrates an operational environment for a converged radio unit (RU), in accordance with some embodiments. 
         FIG.  7    illustrates a procedure performed by a machine learning model, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. 
     Some embodiments disclosed herein provide a retransmission decision based solely off of the PHY parameters, such as residual indicators from the electromagnetic transmission, IQ samples, and/or LO frequencies. In these embodiments, the complexity needed by contemporary wireless repeaters is reduced allowing for improved retransmission time, reducing environmental noise from the wireless channel, and enabling sematic-less retransmissions. 
     Some embodiments of the semantic-less wireless repeater disclosed herein utilizes machine learning and launders the wireless signal to remove interferers. Embodiments disclosed herein provide a specific set of mechanisms for deciding whether or not to retransmit a given signal. 
     In some embodiments, the semantic-less wireless repeater may identify and authenticate transmissions. After authenticating the transmission, PHY layer metrics, such as error magnitude from IQ sample(s), are used to decide whether or not a retransmission is appropriate and necessary. Upon deciding that a retransmission will occur, some embodiments may launder the signal to remove any jamming and/or interference that may have been introduced during the transmission. 
     Some embodiments are directed to a converged radio unit (RU) configured for semantic-less retransmissions. In these embodiments, the converged RU may comprise a radio-frequency machine learning (RFML) radio unit (RFML RU) and a radio-access network (RAN) radio unit (RU). The RFML RU may be configured to receive an RF signal comprising a packet, decode a PHY layer preamble of the packet, and apply a machine-learning (ML) model to information obtained from only the PHY layer preamble to classify the packet. In these embodiments, when the packet is classified be a tactical data link (TDL) packet based on the information obtained only from the PHY layer preamble, the RFML RU may retransmit the packet. In these embodiments, when the packet is classified a RAN protocol packet, the RFML RU may be configured to signal the RAN RU to process the RAN protocol packet in accordance with a RAN protocol. These embodiments as well as others, are described in more detail below. 
       FIG.  1    illustrates an RF repeater configured for semantic-less retransmissions in accordance with some embodiments. The RF repeater may include receiver circuitry  102  to demodulate the received RF signal, authentication circuitry  104  to authenticate the received RF signal based on one or more authentication features  114  and retransmission determination circuitry  106  to determine whether or not to retransmit the received RF signal based on one or more retransmission features  116 . The RF repeater may also include remodulation and retransmission circuitry  108  to remodulate and retransmit the received RF These embodiments are described in more detail below. 
     The RF repeater may also include one or more antennas. The antennas may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result. 
     Although the RF repeater  100  is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements. 
     Embodiments may be implemented in one or a combination of hardware, firmware and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device. 
     Some embodiments described herein are directed to a radio-frequency (RF) repeater configured for semantic-less retransmissions. The RF repeater may be configured to perform physical (PHY) layer processing to identify one or more PHY layer features of a received RF signal. The RF repeater may determine whether or not to retransmit the received RF signal based on the one or more PHY features. In these embodiments, the determination to retransmit the received RF signal may he based solely on PHY parameters enabling semantic-less retransmissions. 
     In some embodiments, the RF repeater may refrain from performing any medium access control (MAC) layer processing or other higher-layer processing to determine whether or not to retransmit the received RF signal. In some embodiments, to refrain from performing MAC layer processing, the RF repeater may refrain from hit parsing, decoding or reading packet headers and IP addresses to determine whether to retransmit the RF signal. In these embodiments, MAC layer processing is not performed and the received RF signal may be retransmitted regardless of the underlying protocol. 
     In some embodiments, the RF repeater may authenticate the received RF signal based on one or more authentication features  114  (i.e., features 1-N used for authentication). In these embodiments, if the received RF signal is authenticated, the RF repeater may determine whether or not to retransmit the received RF signal based on one or more retransmission features  116  (i.e., features 1-N used for authentication). In these embodiments, the RF repeater may refrain from retransmitting the received RF signal when not authenticated. In these embodiments, the one or more authentication features  114  and the one or more retransmission features  116  may be stored in memory. 
     In some embodiments, the RF repeater may determine which set of RF signals to retransmit and which set of RF signals not to retransmit based on authentication. In some of these embodiments, the RF repeater may include authentication circuitry  104  to authenticate the received RF signal based on one or more authentication features  114  and retransmission determination circuitry  106  to determine whether or not to retransmit the received RF signal based on one or more retransmission features  116 . In these embodiments, the received RF signal may be authenticated based on a first set of features  114  (e.g., frequency error or offset) and the decision to retransmit may be based on a second set of features  116 . In some of these embodiments, the memory may store the identities or characteristics of devices whose signals will be retransmitted. 
     In some embodiments, the RF repeater may determine the one or more authentication features  114  using in-phase (I) and quadrature-phase (Q) samples generated from the received RF signal. In these embodiments, the one or more authentication features  114  comprise an error vector magnitude of the I and Q samples (e.g., an I-Q symbol error) and a local-oscillator (LO) signal presence in the received RF signal, although the scope of the embodiments is not limited in this respect. In these embodiments, the RF repeater may authenticate the received RF signal when the error vector magnitude of the I and Q samples is below a predetermined threshold and/or based on a ratio of the LO signal level to the RF signal level (e.g., a ratio or quantity of the LO that may be present in the received RF signal). 
     In some embodiments, the one or more authentication features  114  further comprise: modulation type, a chip rate, a chip-set identifier, a signal rise time, an I-Q symbol error, and local-oscillator (LO) signal presence. In some of these embodiments, characteristics of the I and Q samples may be used to authenticate the received RF signal, although the scope of the embodiments is not limited in this respect. The characteristics, for example, may include frequency error or offset, although the scope of the embodiments is not limited in this respect. In these embodiments, the characteristics of the I and Q samples may be used to authenticate the received RF signal and identify the transmitter (i.e., authenticate the sender). In these embodiments, examples of the modulation type used for authentication may comprise QPSK vs QAM, Frequency Hopping vs Direct Sequence Spread Spectrum, etc. 
     In some embodiments, characteristics that are not based on I and Q samples may be used to authenticate the received RF signal. In these embodiments, an LO offset may be used, for example, although the scope of the embodiments is not limited in this respect as other authentication features may also be used. In some embodiments, the RF repeater may authenticate the received RF signal based on RF fingerprinting using an RF machine learning (RFML) technique using the I and Q samples. 
     In some embodiments, the retransmission features  116  may comprise at least one of an I-Q sample region and a signal-to-noise ratio (SNR) of the received RF signal. In these embodiments, the RF repeater may determine whether or not to retransmit the received RF signal, based on for example, when the I and Q samples of the received RF signal fall within the I-Q sample region, and when the SNR of the received RF signal is within a predetermined SNR range. 
     In some embodiments, the RF repeater may retransmit if the I and Q samples fall within specific region (see region  402  of  FIG.  4    described in more detail below). For example, based on the I and Q samples, the processing circuity may determine if the RF repeater is too close to the actual sender and therefore there may be no need to retransmit the RF signal. On the other hand, based on the I and Q samples, the processing circuity may determine if the RF repeater is far enough away from the actual sender and therefore may retransmit the RF signal. Based on the I and Q samples, the processing circuity may also determine if the RF repeater is too far enough away from the intended recipient and therefore may refrain from retransmission of the RF signal. 
     In some embodiments, prior to remodulation of the I and Q samples for retransmission of the received RF signal, the RF repeater may process the I and Q samples to remove noise and interference, although the scope of the embodiments is not limited in this respect. In these embodiments, the remodulation and retransmission circuitry  108  of the RF repeater may be configured to remodulate the I and Q samples for retransmission of the received RF signal after processing the I and Q samples to remove noise and interference. In these embodiments, the remodulation and retransmission circuitry  108  may reduce or remove noise and interference when remodulating prior to retransmission. In these embodiments, the received RF signal may be laundered as any jamming signals or interferers may be removed. 
     In some embodiments, the receiver circuitry  102  may demodulate the received RF signal to generate the I and Q samples of the received RF signal. 
     In some embodiments, the RF repeater may be configured for operation as a node in a multi-hop network. In these embodiments, the RF repeater may route (i.e., retransmit) the received. RF signal to a next-hop node) when authenticated based solely on the PHY layer features. In these multi-hop embodiments, routing the received RF signal to a next-hop node comprises retransmitting the RF signal non-directionally or directionally. In these multi-hop embodiments, RF signals are authenticated at each hop of the multi-hop network. This allows for authentication of network users and increases network resilience, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, processing elements of the RF repeater may comprise an FPGA. In some embodiments, the elements of the RF repeater may be fabricated as part of an Application Specific Integrated Circuit (ASIC) or Radio Frequency Integrated Circuit (RFIC), although the scope of the embodiments is not limited in this respect. 
     Some embodiments are directed to a method for semantic-less retransmissions (e.g., see  FIG.  2   ). The method may include performing physical (PHY) layer processing to identify one or more PRY layer features of a received RF signal and determining whether or not to retransmit the received RF signal based on the one or more PHY features. In some of these embodiments, performing the PHY layer processing may comprise generating in-phase (I) and quadrature-phase (Q) samples of the received RF signal, although the scope of these embodiments is not limited in this respect. In some embodiments, the method may include authenticating the received RF signal based on one or more authentication features  114  determined from the I and Q samples. In some of these embodiments, if the received RF signal is authenticated, the method may include determining whether or not to retransmit the received RF signal based on one or more retransmission features determined from the I and Q samples. 
     Some embodiments are directed to a non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of an RF repeater configured for semantic-less retransmissions. These embodiments are described in more detail below. 
       FIG.  2    is a flow chart illustrating operations performed by an RF repeater configured for semantic-less retransmissions in accordance with some embodiments. The procedure for semantic-less retransmissions  200  illustrated in  FIG.  2    may be performed by an RF repeater, such as the RF repeater illustrated in  FIG.  1   , although other RF repeater configurations may be suitable. 
     In operation  202 , PHY layer processing is performed on a received RF signal to identify one or more PHY layer features of a received RF signal. In some embodiments, performing the PHY layer processing may generating in-phase (I) and quadrature-phase (Q) samples of the received RF signal, although the scope of the embodiments is not limited in this respect. 
     In operation  204 , the received RF signal may be authenticated based on one or more authentication features. If the RF signal is authenticated (operation  206 ), operation  208  may be performed. If the RF is not authenticated, operation  214  may be performed. In some embodiments, one or more authentication features may be determined from the I and Q samples 
     In operation  208 , one or more retransmission features are identified to determine whether or not to retransmit. Based on the identified retransmission features (operation  210 ), operation  212  may be performed when it is determined to retransmit the received RF signal, and operation  214  may be performed when it is determined not to retransmit the received RF signal. 
     In operation  212 , the received RF signal is remodulated for retransmission, and interference and noise may be removed. 
     In operation  214 , the RF repeater may refrain from retransmitting the received RF signal. 
       FIG.  3    illustrates a block diagram of an example processing system  300  upon which any one or more of the techniques (e.g., methodologies) discussed herein may perform. In some embodiments, processing system  300  may operate as part of RF repeater  100  ( FIG.  1   ). In alternative embodiments, the processing system  300  may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the processing system  300  may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the processing system  300  may act as a peer machine in peer-to-peer (P2P) (or other distributed) network environment. The processing system  300  may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a smart phone, a web appliance, a network router, switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations. 
     Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a non-transitory computer-readable storage medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. In some embodiments, the non-transitory computer-readable storage medium may store instructions for execution by one or more processors or processing circuitry, to perform the operations described herein. 
     Accordingly, the term “module” is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time. 
     Processing system  300  may include processing circuitry such as a hardware processor  302  (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory  304  and a static memory  306 , some or all of which may communicate with each other via an interlink (e.g., bus)  308 . The processing system  300  may further include a display unit  310 , an alphanumeric input device  312  (e.g., a keyboard), and a user interface (UI) navigation device  314  (e.g., a mouse). In an example, the display unit  310 , input device  312  and UI navigation device  314  may be a touch screen display. The processing system  300  may additionally include a storage device (e.g., drive unit)  316 , a signal generation device  318  (e.g., a speaker), a network interface device  320 , and one or more sensors  321 , such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The processing system  300  may include an output controller  328 , such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.). 
     The storage device  316  may include a machine readable medium  322  on which is stored one or more sets of data structures or instructions  324  (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions  324  may also reside, completely or at least partially, within the main memory  304 , within static memory  306 , or within the hardware processor  302  during execution thereof by the processing system  300 . In an example, one or any combination of the hardware processor  302 , the main memory  304 , the static memory  306 , or the storage device  316  may constitute machine readable media. 
     While the machine readable medium  322  is illustrated as a single medium, the term “machine readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions  324 . 
     The term “machine readable medium” may include any non-transitory medium that is capable of storing, encoding, or carrying instructions for execution by the processing system  300  and that cause the processing system  300  to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, machine readable media may include non-transitory machine readable media. In some examples, machine readable media may include machine readable media that is not a transitory propagating signal. 
     The instructions  324  may further be transmitted or received over a communications network  326  using a transmission medium via the network interface device  320  utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks, among others. In an example, the network interface device  320  may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network  326 . In an example, the network interface device  320  may include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. In some examples, the network interface device  320  may wirelessly communicate using Multiple User MIMO techniques. The term “transmission medium” shall be taken to include any tangible medium that is capable of storing, encoding or carrying instructions for execution by the processing system  300 , and includes digital or analog communications signals or other tangible medium to facilitate communication of such software. 
       FIG.  4    shows an I-Q sample region for use in determining whether or not to retransmit a received RF signal, in accordance with some embodiments. In these embodiments, when the I-Q samples  401  of a received RF signal reside within region  402 , the processing circuitry may configure the RF repeater to retransmit the received RF signal once authenticated. When the I-Q samples of a received RF signal reside outside region  402 , the processing circuitry may configure the RF repeater to refrain from retransmitting the received RF signal. Region  402  may be based on an amount of error that is to be accommodated, although the scope of the embodiments is not limited in this respect. 
       FIG.  5    is a functional block diagram of a converged radio unit (RU), in accordance with some embodiments. Converged radio unit (RU)  500  may be configured for semantic-less retransmissions. In these embodiments, the converged RU  500  may include a radio-frequency machine learning (RFML) radio unit (RFML RU)  502  and a radio-access network (RAN) radio unit (RU)  504 . In these embodiments, the RFML RU  502  may be configured to receive an RF signal comprising a packet, decode a PHY layer preamble of the packet, and apply a machine-learning (ML) model to information obtained from only the PHY layer preamble to classify the packet. In these embodiments, when the packet is classified be a tactical data link (TDL) packet based on the information obtained only from the PHY layer preamble, the RFML RU  502  may retransmit the packet. In these embodiments, when the packet is classified a RAN protocol packet based on the information obtained only from the PHY layer preamble, the RFML RU  502  may be configured to signal (i.e., trigger) via link  505  the RAN RU  504  to process the RAN protocol packet in accordance with a RAN protocol. 
     In these embodiments, the RFML RU  502  may comprise processing circuitry (e.g., processor  302  ( FIG.  3   )) to configure the RFML RU  502  to perform the operations described herein. In some embodiments, the RFML RU  502  may decompose the packet into different features for use by the ML model. In some embodiments, the packet may be decomposed into up to eight or more different features. In some embodiments, a Few Shot Learning (FSL) model may be applied by the RFML RU  502  to the decomposed features. These embodiments are described in more detail below (see  FIG.  7   ). In the example embodiment illustrated in  FIG.  5   , the converged RU may be located within a base station  506 , although this is not a requirement. 
       FIG.  6    illustrates an operational environment for a converged radio unit (RU), in accordance with some embodiments. Converged RU  500  ( FIG.  5   ) may operate with a base station and may receive TDL packets over TDLs  602  and may receiver RAN network packets over RAN links  604 . In some embodiments, when the packet is classified as a TDL packet, the RFML RU  502  may also be configured to determine, based on the application of the ML model, a transmitter-receiver (TX-RX) pair communicating via a TDL  602  (see  FIG.  6   ) and may forward the TDL packet for transmission via the appropriate TDL  602 . In these embodiments, the ML model may be applied only the PHY layer preamble of the packet. In these embodiments, TDL packets may be received from TDLs  602  and RAN protocol packets may be received from RAN links  604  (see  FIG.  6   ). 
     In some embodiments, the TX-RX pair may be determined from subtle hardware imperfections (e.g., “nonlinearities”) which are determined by application of the ML model to the PHY layer preamble of the packet. In these embodiments, for TDL packets, the converged RU  500  may operate as a radio-frequency (RF) repeater that configured for semantic-less retransmissions (e.g., see  FIG.  1   ). 
     In some embodiments, for a TDL packet, the RFML RU  502  may also be configured to predict a recipient for the TDL packet based on the application of the ML model to the PHY layer preamble of the packet, and determine if the recipient of the TDL packet can be reached by retransmission of the TDL packet. In these embodiments, the converged RU may configure the RFML RU  502  to retransmit the TDL packet when the recipient can be reached by retransmission. In some embodiments, the RFML RU  502  may determine if the recipient of the TDL packet can be reached indirectly by retransmission of the TDL packet to a neighbor node, which may be an intermediate node of a TDL network for forwarding by the neighbor node to the recipient. 
     In some embodiments, the ML model may be a FSL model and may use a decomposed set of features to make these decisions, although the scope of the embodiments is not limited in this respect. In some embodiments, the FSL model uses a machine learning framework that enables a pre-trained model to generalize over new categories of data that a pre-trained model has not seen during training, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, for a TDL packet, the RFML RU  502  may be configured to apply the ML model without decoding or attempting to decode any lower layers of the TDL packet including a medium access control (MAC) layer. In these embodiments, for a TDL packet that is encrypted, the RFML RU  502  may be configured to apply the ML model without decrypting the TDL packet. 
     In these embodiments, zero-trust network access is provided for legacy tactical data links via a single device (i.e., the converged RU) that also provides RAN connectivity. In these embodiments, the RFML RU  502  may learn RF signatures and may be able to distinguish between devices sending the same message due to subtle hardware imperfections (e.g., “nonlinearities”) that may be unique to each device, although the scope of the embodiments is not limited in this respect. In these embodiments, since packets transmitted via a TDL may be encrypted, without a key it may not be possible to decode any lower layers of a TDL packet. 
     In some embodiments, the RFML RU  502  may be configured to refrain from decoding or attempting to decode any lower layers (i.e., any layers below the PHY layer) of the packet including a MAC layer to obtain additional information about the packet. In these embodiments, for a TDL packet that is encrypted, the RFML RU  502  may be configured refrain from decrypting the TDL packet. In these embodiments, the RFML RU  502  may refrain from performing medium access control (MAC) layer processing on a received packet. In these embodiments, to refrain from performing MAC layer processing, the RFML RU  502  may refrain from bit parsing, decoding or reading packet headers and IP addresses. 
     In some embodiments, the ML model comprises a Few Shot Learning (FSL) model, although other ML models may also be suitable. 
       FIG.  7    illustrates a procedure  700  performed by a machine learning model, in accordance with some embodiments. In some embodiments, after a new reception  702  of the packet, the RFML RU  502  ( FIG.  5   ) may be configured to extract  704  separate the PHY layer preamble from the packet, decode  706  the extracted PHY layer preamble, and re-encode  708  the preamble in a format for the ML model prior to querying the ML model in operation  710  and application of the ML model to the preamble. 
     In some embodiments, after the application of the ML model, the RFML RU  502  may further be configured to predict  712  one or more possible recipients of the packet, identify  714  one or more possible neighbors, and check accuracy of the prediction  716 . In these embodiments, when the prediction is accurate  718 , the converged RU  500  may be configured to retransmit  724  the packet. 
     In some embodiments, the RFML RU  502  may be configured to transmit the packet directionally (i.e., in a direction of the recipient) based on a location of the recipient, although the scope of the embodiments is not limited in this respect. In some embodiments, when the prediction is not correct, the ML model may check other neighbors (K) in operation  720 . In these embodiments, operation  720  may including tracking one or more neighbors to determine if the recipient is accessible through a neighbor. Operation  722  may check the accuracy of a neighbor predicted or identified in operation  720 , and when the prediction is accurate, configure the converged RU  500  to retransmit the packet in operation  724 . When a packet is not able to be classified as a TDL packet or when a recipient or neighbor is unable to be accurately identified, operation  726  may be performed. When the packet is classified a RAN protocol packet based on the information obtained from the PHY layer preamble, the RFML RU  502  may configured to signal the RAN RU  504  in operation  726  to process the RAN protocol packet in accordance with a RAN protocol. 
     Referring back to  FIG.  5   , in some embodiments, the RAN RU  504  may be configured to operate as a radio unit an O-RAN radio unit configured to be connected to a distributed unit (DU) of an open radio access network (O-RAN). In some embodiments, the RAN RU  504  may be configured to operate as a radio unit an cellular network radio unit comprising at least one of a 4 th  generation long-term evolution (4G LTE) and a 5 th  generation new radio (5G NR) radio unit. In some embodiments, the RAN RU  504  may be configured to operate as an access point or station for an WLAN for an IEEE 802.11 protocol, although the scope of the embodiments is not limited in this respect. In some embodiments, the RAN RU  504  may include 6 th  generation radio unit functionality. 
     In some embodiments, the RAN RU  504  comprises a baseband processor. In these embodiments, to process the packet in accordance with the RAN protocol when the packet is classified a RAN protocol packet, the RAN RU  504  may be configured to demodulate the RAN protocol packet based on the RAN protocol using the baseband processor. In these embodiments, the RAN RU  504  may decode a MAC layer of RAN protocol packet. 
     In some embodiments, the RFML RU  502  may further be configured to determine one or more authentication features using in-phase (I) and quadrature-phase (Q) samples generated from the received RF signal, authenticate the RF signal based on the one or more authentication features, and for a TDL packet, determine whether or not to retransmit the packet based whether the receive RF signal is authenticated. 
     In some embodiments, the one or more authentication features comprise an error vector magnitude of the I and Q samples and a local-oscillator (LO) signal presence in the received RF signal. In some embodiments, the one or more authentication features further comprise: modulation type, a chip rate, a chip-set identifier, a signal rise time, an I-Q symbol error, and local-oscillator (LO) signal presence. In some embodiments, the RFML RU  502  may further configured to authenticate the received RF signal based on RF fingerprinting. 
     Some embodiments are directed to a non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of a converged radio unit (RU)  500  (see  FIG.  5   ) configured for configured for semantic-less retransmissions. In these embodiments, the converged RU  500  may comprise a radio-frequency machine learning (RFML) radio unit (RFML RU)  502  and a radio-access network (RAN) radio unit (RU)  504 . In these embodiments, the processing circuitry may configure the RFML RU  502  to receive an RF signal comprising a packet, decode a PHY layer preamble of the packet, and apply a machine-learning (ML) model to information obtained from only the PHY layer preamble to classify the packet. In these embodiments, when the packet is classified be a tactical data link (TDL) packet based on the information obtained only from the PHY layer preamble, the RFML RU  502  may be configured to retransmit the packet. When the packet is classified a RAN protocol packet based on the information obtained only from the PHY layer preamble, the RFML RU  502  may be configured to signal via link  505  the RAN RU  504  to process the RAN protocol packet in accordance with a RAN protocol. 
     Some embodiments are directed to a method performed by processing circuitry of a converged radio unit (RU)  500  (see  FIG.  5   ) configured for semantic-less retransmissions. In these embodiments, the converged RU  500  may comprise a radio-frequency machine learning (RFML) radio unit (RFML RU)  502  and a radio-access network (RAN) radio unit (RU)  504 . In these embodiments, the method may comprise receiving an RF signal comprising a packet, decoding a PHY layer preamble of the packet, and applying a machine-learning (ML) model to information obtained from only the PHY layer preamble to classify the packet. In these embodiments, when the packet is classified be a tactical data link (TDL) packet based on the information obtained only from the PHY layer preamble, the method comprises retransmitting the packet. In these embodiments, when the packet is classified a RAN protocol packet based on the information obtained only from the PHY layer preamble, the method comprises signaling the RAN RU  504  to process the RAN protocol packet in accordance with a RAN protocol. 
     The Abstract is provided to comply with 37 C.F.R. Section 1.72(b) requiring an abstract that will allow the reader to ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.