Low data rate low power transmission using portable network communication module

Abstract

A portable network communication module may be used to provide low data rate, low power bi-directional transmission on existing physical communication media (e.g., coaxial cable) and in the presence of a higher bandwidth, higher power primary signal currently transmitted over the communication media. A low data rate, low power two-way transmission may be achieved using a spread spectrum modulation signal positioned in frequency relative to a primary signal, such that the low data rate, low power transmission may occur without detectable interference with the primary signal, including a multiplexed narrowband modulation signal. The primary signal may be modulated using quadrature amplitude modulation (QAM) and may be multiplexed using Orthogonal Frequency Division Multiplexing (OFDM) and the spread spectrum modulated signal may be modulated using Gaussian Frequency Shift Keying (GFSK) to a linear spread spectrum (CSS) modulated signal. One example of a spread spectrum modulation signal is implemented using a LoRa technology and a communication protocol defined by the LoRaWAN standard.

Description

Technical Field

[0001] The invention belongs to the field of communication, and in particular to the use of a portable network communication module for low data rate and low power transmission. Background Art

[0002] Broadband communication networks are used to provide high-speed, high-frequency transmission to and from devices in the network through communication paths. In some broadband networks, such as hybrid fiber-coaxial (HFC) networks used for CATV, at least a portion of the communication path includes coaxial cables that transmit both downstream and upstream radio frequency (RF) signals. For example, in a CATV network, the downstream RF signal may include video and IP data transmitted from the headend of the HFC network to the subscriber device and the upstream RF signal may include control and IP data transmitted from the subscriber device to the headend. In such broadband networks, it is often desirable to transmit additional information, such as control or status data, to or from devices in the network in order to have a more resilient and reliable broadband network and to enable preemptive strategic maintenance to avoid interruptions. However, there are some challenges in providing additional two-way transmission over coaxial cable and other physical communication media without interfering with existing downstream and upstream RF signals.

[0003] For example, in an HFC network, a coaxial distribution network may include RF amplifiers to extend the transmission distance of RF signals and thus the coverage of CATV services provided to subscriber locations. For the purpose of remotely controlling and / or monitoring the RF amplifiers, it is desirable to provide two-way communication with the RF amplifiers. According to one solution, a DOCSIS cable modem transponder may be included in the RF amplifier to provide control of the RF amplifier and communication with the RF amplifier; however, the DOCSIS transponder tends to consume a large amount of power and generate a large amount of heat. As the bandwidth of broadband networks increases (e.g., up to 1.8 GHz and above), managing the power consumption and heat generated in network devices has been a greater challenge. In RF amplifiers in CATV networks, in particular, the amplification of CATV RF signals may consume a large amount of power while generating excessive heat, especially as the bandwidth of CATV networks expands. Including additional components in the RF amplifier may bring additional challenges in reducing power consumption and limiting energy dissipation and heat. Furthermore, some HFC networks only allow the RF amplifier to be controlled and / or communicated with from the head end of the CATV network, which does not allow those skilled in the art to easily repair the RF amplifier in the HFC network.

[0004] Therefore, there is a need for a relatively low power system and method of providing bidirectional communications over existing coaxial cables in a broadband network without substantially interfering with existing downstream and upstream RF signals from various locations in the network. Summary of the invention

[0005] According to one aspect of the present invention, a method for communicating with a radio frequency (RF) amplifier in a hybrid fiber coaxial (HFC) network is provided. The HFC network includes a headend, at least one HFC node coupled to the headend with an optical fiber, and a coaxial cable distribution network including a plurality of coaxial cables and a plurality of RF amplifiers coupled to the coaxial cables. At least one of the RF amplifiers and / or at least one node includes a transponder and the headend includes a gateway device. The method includes: transmitting a downstream main signal from the headend to the coaxial cable distribution network, wherein the downstream main signal is amplified by the RF amplifier; transmitting an upstream main signal from the coaxial cable distribution network to the headend, wherein the upstream main signal is amplified by the RF amplifier; connecting a portable network communication module to the HFC node; and establishing bidirectional transmission between at least one of the transponders and a portable network communication module for transmitting a downstream control signal from the portable network communication module to at least one of the transponders and / or for transmitting an upstream data signal from at least one of the transponders to the portable network communication module. Bidirectional transmission of a spread spectrum modulated signal and downstream and upstream main signals on a coaxial cable. The spread spectrum modulated signal used for the bidirectional transmission has a lower data rate and lower power than the downstream and upstream main signals and is positioned in frequency relative to the downstream and upstream main signals so that the bidirectional transmission occurs without detectable interference with the downstream and upstream main signals.

[0006] According to another aspect of the present invention, a portable network communication module is provided for use in a hybrid fiber coaxial (HFC) network including a coaxial cable distribution network. The portable network communication module includes a computing device, a gateway processor coupled to the computing device, and at least one gateway transceiver coupled to the gateway processor and used to transmit a downstream control signal and to receive an upstream data signal. The downstream control signal and the upstream data signal are spread spectrum modulated signals that can be transmitted on the coaxial cable distribution network together with the downstream and upstream main signals. The spread spectrum modulated signal has a lower data rate and a lower power supply than the downstream and upstream main signals and is positioned in frequency relative to the downstream and upstream main signals so that bidirectional transmission of the spread spectrum signal occurs without detectable interference with the downstream and upstream main signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features and advantages will be better understood by reading the following detailed description and accompanying drawings, in which:

[0008] Figure 1 FIG. 4 is a schematic diagram of a hybrid fiber-coaxial (HFC) network for CATV according to an embodiment of the present invention.

[0009] Figure 2FIG. 4 is a schematic diagram of a conventional HFC network for low data rate, low power bidirectional transmission between a network device and a head end according to an embodiment of the present invention.

[0010] Figure 2A FIG. 4 is a schematic diagram of a conventional HFC network for performing low data rate, low power bidirectional transmission between a network device and a portable network communication module according to an embodiment of the present invention.

[0011] Figure 3 FIG. 1 is a schematic diagram of a remote PHY (R-PHY) HFC network for low data rate, low power bidirectional transmission between a network device and a headend according to an embodiment of the present invention.

[0012] Figure 4 The diagram is a schematic diagram of a gateway device used in a headend of an HFC network to provide low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0013] Figure 4A Schematic diagram of a portable network communication module for connecting nodes to provide low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0014] Figure 5 Schematic diagram of an RF amplifier including an electronic amplifier circuit and a transponder for low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0015] Figure 5A To illustrate Figure 5 Schematic diagram of an embodiment of an electronic amplifier circuit in an RF amplifier.

[0016] Figure 5B To illustrate Figure 5 Schematic diagram of an embodiment of an RF amplifier in a transponder.

[0017] Figure 6 FIG. 4 is a schematic diagram of a LoRa network architecture that can be used to implement low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0018] Figure 7 FIG. 4 is a schematic diagram of a LoRa network protocol that can be used to implement low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0019] Figure 8 FIG. 1 is a schematic diagram of a LoRa protocol stack that can be used to implement low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0020] Fig. 9 FIG. 4 is a schematic diagram of a LoRa packet format that can be used to implement low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0021] Fig.10 FIG. 1 is a diagram of a portion of a signal spectrum in a CATV network showing locations between multiple QAM channels for inserting spread spectrum signals for low data rate, low power bidirectional transmission according to an embodiment of the present invention.

[0022] [Description of Reference Numerals]

[0023] 100: HFC network

[0024] 102: Subscribers

[0025] 110: Headend / Hub

[0026] 111: Forward path optical fiber

[0027] 112: Fiber optic relay line

[0028] 113: Return or reverse path fiber

[0029] 114: Node

[0030] 115: Coaxial cable

[0031] 116: Cable Distribution Network

[0032] 117: Tap

[0033] 118: Client device

[0034] 119: Line Extension RF Amplifier

[0035] 200: HFC network

[0036] 210: Headend

[0037] 212: Fiber Optic

[0038] 214: Node

[0039] 216: Coaxial cable

[0040] 219a~219c:RF amplifier

[0041] 220: CMTS

[0042] 222: Combined Network / Optical TX / RX

[0043] 226: Gateway device

[0044] 228: PNM system

[0045] 240: Portable network communication module

[0046] 300: HFC network

[0047] 310: Headend

[0048] 312: Fiber Optic

[0049] 314: Node

[0050] 316: Coaxial cable

[0051] 319a~319c:RF amplifier

[0052] 320: CCAP Core

[0053] 322: CIN

[0054] 324: OOB Core

[0055] 326: Gateway device

[0056] 328: PNM System

[0057] 330: RPD

[0058] 340: Portable network communication module

[0059] 400: Gateway device

[0060] 402: Portable network communication module

[0061] 410: Host computer

[0062] 412: Gateway Processor

[0063] 414-1~414-n:Transceiver

[0064] 420: Computing Devices

[0065] 422: Gateway Processor

[0066] 424: Gateway transceiver

[0067] 426: Power

[0068] 428: Communication port

[0069] 430: User interface device

[0070] 500: RF Amplifier

[0071] 501: Coaxial cable

[0072] 502: Port

[0073] 503: Coaxial cable

[0074] 504: Port

[0075] 506: Forward signal

[0076] 508: Reverse signal

[0077] 510: Transponder

[0078] 512: RF transceiver

[0079] 514: RX matching circuit

[0080] 516: TX matching circuit

[0081] 518: Frequency Down Converter

[0082] 519: TXCO

[0083] 520: eAMP circuit

[0084] 522: Duplex filter

[0085] 524: Duplex filter

[0086] 526: Electrical Path

[0087] 528: Electrical Path

[0088] 530: MCU

[0089] 542: Gain stage

[0090] 544: Gain stage

[0091] 610: Terminal device

[0092] 612: Gateway

[0093] 614: Network Server

[0094] 616: Application Server

[0095] 620: MAC layer

[0096] 621: Frame

[0097] 622: MAC header

[0098] 624: MAC payload

[0099] 626: MIC

[0100] 630: Physical layer

[0101] 631: LoRa frame

[0102] 632: Preamble

[0103] 634: PHY header

[0104] 636: PHY payload

[0105] 638: CRC

[0106] 640: Application layer

[0107] 641: Application layer packet

[0108] 642: Frame header

[0109] 643: Device address

[0110] 644: Frame port

[0111] 645: Frame Control

[0112] 646: frame payload

[0113] 647: frame counter

[0114] 649: Frame Options

[0115] DS RF: Downstream RF signal

[0116] eAMP-1~eAMP-n

[0117] US RF: Upstream RF signal

[0118] SPI: Serial Peripheral Interface DETAILED DESCRIPTION

[0119] A system and method for low data rate, low power bidirectional transmission according to an embodiment of the present invention may be provided using a portable network communication module over existing physical communication media (e.g., coaxial cable and / or optical fiber) and in the presence of a higher bandwidth, higher power primary signal currently transmitted over the communication media. Low data rate, low power bidirectional transmission may be achieved using a spread spectrum modulated signal positioned in frequency relative to the primary signal, such that the low data rate, low power transmission occurs without detectable interference with the primary signal (including multiplexed narrowband modulated signals). In some embodiments, the primary signal may be modulated using quadrature amplitude modulation (QAM) and the primary signal may be multiplexed using orthogonal frequency division multiplexing (OFDM) and the spread spectrum modulated signal may be modulated using Gaussian frequency shift keying (GFSK) to a linear spread spectrum (CSS) modulated signal. An example of a spread spectrum modulated signal is implemented using LoRa technology and communication protocols defined by the LoRaWAN standard. Although systems and methods for low data rate, low power bidirectional transmission are described in the context of a hybrid fiber-coaxial (HFC) network for communicating with network devices (e.g., nodes and / or RF amplifiers), such transmission may be implemented in any type of network that uses existing physical communications media for higher bandwidth communications.

[0120] As used herein, "channel" refers to a frequency sub-range within a frequency spectrum that can be modulated to transmit information. "Channel" can be identified as a single frequency in a frequency sub-range, and as used herein, "selecting a channel" can include selecting a single frequency that identifies a channel. As used herein, "main communication channel" refers to a channel in a defined telecommunications band (e.g., a CATV channel), and "main signal" refers to a signal transmitted using the main communication channel. As used herein, a "downstream main signal" (also known as a forward main signal) is a main signal transmitted from a source (e.g., a CATV head end / hub) to a destination (e.g., a CATV subscriber), and an "upstream main signal" (also known as a reverse main signal) is a main signal transmitted from a destination (e.g., a CATV subscriber) to a source (e.g., a CATV head end / hub). As used herein, "channel spectrum" refers to a predefined radio frequency range that is divided into multiple frequency sub-ranges (referred to as physical channels) and can be modulated to transmit information. "CATV channel spectrum" refers to the channel spectrum used to transmit video and / or data in a CATV network and is not limited to a specific frequency range.

[0121] As used herein, "low data rate" refers to a data rate that is lower than the data rate of the main signal on the main communication channel, and "low power" refers to a signal power that is lower than the signal power of the main signal on the main communication channel. For example, "low data rate" may be in the range of 5 kbps to 100 kbps, and "low power" may be between -10 dBm and 0 dBm.

[0122] As used herein, the term "circuit" or "circuitry" refers to physical electronic components (i.e., hardware) and any software and / or firmware (i.e., program code) that can configure the hardware, be executed by the hardware, and / or otherwise be related to the hardware. For example, a particular processor and memory may include a first "circuit" when executing a first portion of the program code to perform a first function, and may include a second "circuit" when executing a second portion of the program code to perform a second function. As used herein, the term "coupled" refers to any connection, coupling, connection, or similar relationship between multiple elements. Such "coupled" multiple elements do not need to be directly connected to each other and may be separated by intermediate elements.

[0123] Figure 1An example of a hybrid fiber coaxial (HFC) network 100 for CATV that can implement low data rate, low power bi-directional transmission according to an embodiment of the present invention is shown. For example, low data rate, low power bi-directional transmission can be implemented to communicate with line extension RF amplifiers 119 and / or nodes 114 in the HFC network 100, which will be described in more detail later. Generally, the HFC network 100 is capable of delivering both cable television programming (i.e., movies) and IP data services (e.g., Internet and IP voice transmission) to customers or subscribers 102 through the same fiber optic cables and coaxial cables (i.e., trunk lines). Such HFC networks 100 are commonly used by service providers such as Comcast to provide combined video, voice, and broadband Internet services to subscribers 102. Although example embodiments of HFC networks are described herein based on various standards (e.g., Data over Cable Service Interface Specification (DOCSIS)), the concepts described herein can be applied to other embodiments of CATV networks using other standards.

[0124] Multiple cable TV channels and IP data services (such as broadband Internet and IP voice transmission) are transmitted simultaneously in CATV network 100 by using frequency division multiplexing transmission signals on multiple physical channels on the CATV channel spectrum. An example of a CATV downstream channel spectrum (also known as a forward spectrum) includes channels from 650MHz to 1794MHz, but the CATV channel spectrum can be even further extended to increase the bandwidth used for data transmission. In the CATV channel spectrum, some physical channels can be allocated to cable TV channels, and other physical channels can be allocated to IP data services. Other channel spectrums and bandwidths can be used and are within the scope of the present invention.

[0125] In addition to transmitting the main signal (also called forward signal) downstream to transmit video and IP data to subscriber 102, HFC network 100 can also transmit the main signal (such as IP data or control signal) (also called reverse signal) upstream from the subscriber, thereby providing two-way communication through the trunk line. According to one example, the signal spectrum used for the reverse signal carried upstream can be up to 600MHz.

[0126] The HFC network 100 generally includes a headend / hub 110 connected to one or more optical nodes 114 via fiber trunk lines 112 (connected to customer premises equipment (CPE) 118 located at subscriber locations 102 via coaxial cable distribution network 116). The headend / hub 110 receives, processes, and combines content (e.g., broadcast video, narrowcast video, and network data) as optical signals carried by the fiber trunk lines 112. The fiber trunk lines 112 include forward path optical fibers 111 for carrying downstream optical signals from the headend / hub 110 and return or reverse path optical fibers 113 for carrying upstream optical signals to the headend / hub 110. The optical nodes 114 provide an optical-electrical interface between the fiber trunk lines 112 and the coaxial cable distribution network 116. Thus, the optical nodes 114 receive downstream optical signals and send upstream optical signals, and send downstream (forward) RF electrical signals and receive upstream (reverse) RF electrical signals.

[0127] The cable distribution network 116 includes coaxial cables 115 including trunk coaxial cables connected to the optical nodes 114 and feed coaxial cables connected to the trunk coaxial cables. Subscriber drop coaxial cables are connected to the distribution coaxial cables using taps 117 and are connected to client devices 118 located at the subscriber locations 102. The client devices 118 may include set-top boxes for video and cable modems for data. One or more line extension RF amplifiers 119 may also be coupled to the coaxial cables 116 for amplifying forward signals (e.g., CATV signals) carried downstream to the subscribers 102 and for amplifying reverse signals carried upstream from the subscribers 102. In this embodiment, as will be described in more detail below, the optical node 114 and / or the line extension RF amplifier 119 may include a transponder and the headend / hub 110 may include a gateway device to implement low data rate, low power bidirectional transmission along with downstream and upstream main signals having higher bandwidth and power.

[0128] Figure 2 An implementation of a system for low data rate, low power bidirectional transmission in a conventional HFC network 200 according to one embodiment is shown. This embodiment of the HFC network 200 includes a headend 210 coupled to an HFC node 214 using an optical fiber 212, and includes RF amplifiers 219a-c coupled to the HFC node 214 using a coaxial cable 216, which are similar to those described above and Figure 1 HFC network 100 is shown. In this embodiment of HFC network 200, analog communications are provided via optical fiber 212 between headend 210 and HFC node 214.

[0129] In this embodiment of HFC network 200, headend 210 includes a cable modem termination system (CMTS) 220 coupled to a combined network and optical transmitter and receiver (collectively referred to as combined network / optical TX / RX 222). CMTS 220 provides MAC and PHY layer connections to subscriber locations (not shown). Figure 2 ) is used to send the downstream main signal to the subscriber and receive the upstream main signal from the subscriber. The optical transmitter and receiver in the combined network / optical TX / RX 222 send and receive analog optical signals through the optical fiber 212, and the combined network in the combined network / optical TX / RX 222 combines and separates the signals sent and received by the optical transmitter and receiver.

[0130] To establish low data rate, low power bidirectional transmission, the headend 210 further includes a gateway device 226, which may be implemented as a shelf in the headend 210, coupled to the combined network / optical TX / RX 222. In this embodiment, low data rate, low power bidirectional transmission may be combined with analog downstream and upstream main signals in the combined network and transmitted and received by the optical transmitter and receiver. The node 214 and / or the RF amplifier 219a-c may include a transponder (not shown) for establishing low data rate, low power bidirectional transmission with the gateway device 226. Figure 2 ), which will be described in more detail below.

[0131] Please refer to Figure 2A , instead of or in addition to the gateway device 226 in the headend / hub 210, the portable network communication module 240 can be directly connected to the HFC node 214 in the field. The portable network communication module 240 can be a handheld device that plugs into the existing "test point" port in the HFC node 214. The test point port in the HFC node 214 allows access to forward and reverse signals received from and sent to the RF amplifiers 219a-219c downstream of the HFC node 214. Therefore, the portable network communication module 240 can be connected to the test point port in the HFC node 214 to enable communication to and from the RF amplifiers 219a-219c downstream of the HFC node 214 (i.e., the RF amplifiers that share the shared coaxial cable connection with the HFC node 214). Thus, the portable network communication module 240 may allow a technician who is attempting to repair or resolve a problem to access data being transmitted in real time from the RF amplifiers 219 a - 219 c without having to access the fixed gateway device 226 in the headend / hub 210 .

[0132] The portable network communication module 240 can function similarly to the gateway device 226 in the headend / hub 210 and will enable two-way communication. Therefore, the portable network communication module 240 can enable a technician to monitor and adjust amplifier settings in real time (or near real time) on site without requiring another technician in the headend / hub 210 to work remotely.

[0133] As an example of how to use a portable network communication module, a technician may be sent to a node where a problem has been reported. The technician may determine that the problem is coming from one or more RF amplifiers 219a-219c downstream of the HFC node 214, rather than from the HFC node 214 itself. Next, the technician will use appropriate cables to plug the portable network communication module into the downstream and upstream test points on the HFC node 214. If there is no internal power supply (e.g., via a battery), the technician may use an appropriate power cord to connect the portable network communication module to the network for power. Appropriate cables for connecting to test points and power supplies in the HFC node are generally known to those skilled in the art.

[0134] When the portable network communication module is connected and powered, the module can activate a WiFi access point, which can be connected to a user interface device, such as a tablet or smart phone. Opening a browser on the user interface device will display a graphical user interface, which can allow the technician to view real-time (or nearly real-time) data from the amplifier and enable the technician to manipulate the control settings of the amplifier to allow the technician to troubleshoot and adjust the control settings as needed to restore normal operation of the amplifier.

[0135] Figure 3 1 shows an implementation of a system for low data rate, low power bidirectional transmission in a remote PHY type HFC network 300 according to another embodiment. This embodiment of the HFC network 300 also includes a headend 310 coupled to an HFC node 314 using an optical fiber 312, and includes RF amplifiers 319a-c coupled to the HFC node 314 using a coaxial cable 316, which are similar to those described above and Figure 1 The HFC network 100 is shown. In this embodiment of the HFC network 300, digital communications are provided via optical fiber 312 between the headend 310 and the HFC node 314, and the HFC node 314 includes a remote PHY device (RPD) 330 to handle the digital communications. A portable network communication module 340 can also be used in this embodiment of the HFC network 300, for example by directly connecting to the HFC node 314.

[0136] In this embodiment of the HFC network 300, the headend 310 includes an integrated CMTS or converged cable access platform (CCAP) core 320 coupled to a converged interconnect network (CIN) 322. The CCAP core 320 and CIN 322 provide digital optical communication with the RPD 330 in the HFC node 314. The headend 310 also includes a gateway device 326 to establish low data rate, low power bi-directional transmission. In this embodiment, the analog low data rate, low power bi-directional transmission is digitized for communication between the RPD 330 and CIN 322 in the HFC node 314. The RPD 330 converts upstream signals from analog to digital and converts downstream signals from digital to analog, and the headend 310 may include an OOB core 324 coupled to the gateway device 326 to handle A / D and D / A conversion in the headend 310 for low data rate, low power bi-directional transmission.

[0137] The OOB core 324 may use known techniques and standards in the DOCSIS R-PHY specification known as the OOB (out-of-band) communication protocol, which is further defined in the Remote Out-of-Band (CM-SP-R-OOB) specification. As defined in the CM-SP-R-OOB specification, Narrowband Digital Forward (NDF) and Narrowband Digital Return (NDR) digitize a small portion of the spectrum and send the digital samples as the payload within packets transmitted between the CMTS / CCAP core 320 and the RPD 330. This approach is applicable to any type of OOB signal as long as the signal can be contained within the defined passband. The following Tables 16 and 18 are copied from the CM-SP-R-OOB specification and describe the NDF and NDR channel parameters that may be used.

[0138] Table 16 - NDF channel parameters

[0139]

[0140]

[0141] Table 18-NDR channel parameters

[0142]

[0143]

[0144] In both of the above-described embodiments of the HFC network 200, 300, the headend 210, 310 may include a proactive network maintenance (PNM) system 228, 328 coupled to the CMTS 220, 320 and the gateway device 226, 326. The PNM system 228, 328 may be used by the cable operator to preemptively perform strategic maintenance of the network to avoid long outages and have a more resilient and reliable broadband network. Instructions and / or data used by the PNM system 228, 328 may be received and sent via low data rate, low power bidirectional transmission established using the gateway device 226, 326 to provide network maintenance. The PNM system 228, 328 may include an existing PNM system known to those skilled in the art. The headend 210, 310 may use the gateway device 226, 326 and the low data rate, low power bidirectional transmission to transmit instructions and / or data to manage a large number of network devices, such as nodes and RF amplifiers, in the HFC network 200, 300 using an existing network management and control system. Therefore, the system and method for low data rate, low power bidirectional transmission according to embodiments of the present invention provide a relatively simple, reliable and low-cost means to monitor, control and manage broadband networks without detectable interference with the main broadband signal.

[0145] In the above-described embodiments of the HFC networks 100, 200, 300, low data rate, low power bidirectional transmission may utilize a spread spectrum modulated signal that is positioned in frequency relative to a main signal (e.g., a multiplexed narrowband modulated signal) such that the low data rate, low power transmission occurs without detectable interference with the main signal. The spread spectrum signal may be sent with the downstream main signal, such as at a frequency between 150 MHz and 960 MHz, and may be sent with the upstream main signal, such as at a frequency between 5 MHz and 85 MHz. The spread spectrum modulated signal may be a linear spread spectrum (CSS) modulated signal modulated using Gaussian frequency shift keying (GFSK). GFSK modulation may be used at a fixed frequency with a bandwidth of up to 500 KHz, and the spread spectrum bandwidth may be from 7 KHz to 500 KHz. The use of spread spectrum technology reduces the chance of interference or being interfered with by other signals (e.g., the main downstream and upstream signals). An example of implementing spread spectrum modulated signaling using LoRa Technology and the communication protocol defined by the LoRaWAN standard will be described in more detail below.

[0146] Please refer to Figure 4, an embodiment of a gateway device 400 that can be used in the gateway devices 226, 326 in the HFC networks 200, 300 will be described in more detail. In this embodiment, the gateway device 400 includes a host computer 410 that provides a data interface (e.g., Ethernet) to a PNM system or other type of system or application server in the headend. A gateway processor 412 (e.g., a LoRa gateway processor) is coupled to the host computer 410 and a plurality of gateway transceivers 414-1 to 414-n (e.g., LoRa transceivers) are coupled to the gateway processor 412 for sending and receiving spread spectrum signals as downstream RF signals (DS RF) and upstream RF signals (US RF). The gateway processor 412 can be coupled to the transceivers 414-1 to 414-n using a serial peripheral interface (SPI).

[0147] The gateway processor 412 modulates data from the host computer 410 and provides I / Q data of the downstream RF signal (DS RF) to the gateway transceivers 414-1 to 414-n. The gateway processor 412 also receives I / Q data upstream RF signals (US RF) from the gateway transceivers 414-1 to 414-n and demodulates the data. As discussed above, the downstream (DS RF) and upstream (US RF) spread spectrum RF signals from and to the gateway transceivers 414-1 to 414-n can be sent and received along with the downstream and upstream host signals via the combined network / optical TX / RX 222 in the HFC network 200 (see FIG. 2 ). Figure 2 ) or via the OOB core 324 in the HFC network 300 (see Figure 3 ).

[0148] When LoRa technology is used for low data rate, low power bidirectional transmission, the host computer 410, the gateway processor 412, and the gateway transceivers 414-1 to 414-n operate according to the LoRa network architecture, protocol, and packet format, which will be described in more detail later. In an embodiment where the host computer 410 is connected to a PNM system (e.g., PNM system 228, 328), the host computer 410 translates PNM commands and data into LoRa TCP / IP commands and data. An example of the gateway processor 412 is the LoRa gateway baseband processor SX1302 available from Semtech, and an example of the gateway transceivers 414-1 to 414-n is the LoRa transceiver available from Semtech.

[0149] Please refer to Figure 4A, an embodiment of a portable network communication module 402 that can be used in an HFC network (e.g., HFC networks 200, 300) will be described in more detail. In this embodiment, the portable network communication module 402 includes a computing device 420, a gateway processor 422 (e.g., a LoRa gateway processor) coupled to the computing device 420, and one or more gateway transceivers 424 (e.g., LoRa transceivers) coupled to the gateway processor 422. The gateway processor 422 provides modulation and demodulation of spread spectrum signals, and the gateway transceiver 424 sends and receives spread spectrum signals as downstream and upstream RF signals. Downstream and upstream spread spectrum RF signals (DS RF and US RF) from and to the gateway transceiver 424 can be sent and received along with downstream and upstream main signals via test points in HFC nodes (e.g., HFC nodes 214, 314). The portable network communication module 402 can include a communication port 428 for connecting to a test point in the HFC node.

[0150] When LoRa technology is used for low data rate, low power bidirectional transmission, computing device 420, gateway processor 422, and gateway transceiver 424 operate according to the LoRa network architecture, protocol, and packet format, which will be described in more detail later. Gateway processor 422 can be a spread spectrum gateway IC compatible with the IC used in the client unit in the RF amplifier, as described below. An example of gateway processor 422 is the LoRa gateway baseband processor SX1302 available from Semtech, and an example of gateway transceiver 424 is the LoRa transceiver available from Semtech.

[0151] The computing device 420 can collect and store information from the RF amplifier and can format commands to be sent to the RF amplifier. The computing device 420 can include software to facilitate interpreting data from the RF amplifier and formatting commands to make adjustments in the amplifier. For example, the data can be formatted into a web page using HTML or other known network protocols. The computing device 420 can also be used to wirelessly transmit a graphical user interface to a user interface device 430 including a display (such as a tablet computer or smart phone). This communication can use known communication protocols such as WiFi and Bluetooth. In other embodiments, the display device providing the user interface can also be integrated with the portable network communication module 402.

[0152] The portable network communication module 402 may further include a power source 426, such as one or more batteries and / or solar power sources. In other embodiments, the portable network communication module 402 may be configured to connect to a power source supplied by a HFC network via an HFC node.

[0153] like Figure 5As shown, according to an embodiment of the present invention, an RF amplifier 500 (e.g., RF amplifiers 219a-c in HFC network 200 or RF amplifiers 319a-c in HFC network 300) may include a transponder 510 and an electronic amplifier circuit (eAMP) 520. For example, the transponder 510 provides low data rate, low power bidirectional transmission through a gateway device in a headend (e.g., gateway devices 226, 326 in headends 210, 310) to transmit data signals from the amplifier 500 to the headend and / or to receive control signals from the headend in the amplifier 500. The transponder 510 provides low data rate, low power bidirectional transmission with upstream and downstream main signals through coaxial cables 501, 503 coupled to the RF amplifier 500.

[0154] Similar to the transceivers 400-1 to 400-n in the gateway device 400, the transponder 510 uses a spread spectrum modulated RF signal (e.g., a CSS modulated signal or a LoRa signal) to provide low data rate, low power bidirectional transmission. In particular, the transponder 510 can use a downstream path to receive a downstream RF signal (DS RF) from the gateway device 400, and can use an upstream path to send an upstream RF signal (DS RF) to the gateway device 400. By using a spread spectrum modulated signal (e.g., a CSS modulated signal or a LoRa signal), the transponder 510 can send and receive RF signals using relatively low power, such as consuming less than 1 watt inside the amplifier 500, thereby helping to manage power consumption and heat in the RF amplifier 500. The transponder 510 also provides a robust RF interface, such as having a dynamic range of greater than 130 dB and the ability to recover signals up to 20 dB below average noise.

[0155] One embodiment of the eAMP circuit 520 is shown in more detail at Figure 5A In this example, the RF amplifier 500 includes first and second ports 502, 504 for coupling to electrical paths for transmitting forward and reverse RF signals 506, 508, such as coaxial cables carrying the forward RF signal downstream and the reverse RF signal upstream in a CATV network. The first port 502 provides an input for the forward signal 506 and an output for the reverse signal 508, and the second port 504 provides an input for the reverse signal 508 and an output for the forward signal 506.

[0156] The eAMP circuit 520 includes a first duplex filter 522 coupled to the port 502, a second duplex filter 524 coupled to the port 504, and forward and reverse gain stages 542, 544 coupled between the duplex filters 522, 524. The duplex filters 522, 524 separate forward and reverse signals traveling on the same electrical path of the ports 502, 504. The first duplex filter 522 separates and passes the forward signal 506 received on the first port 502 to be amplified by the forward gain stage 542, and the second duplex filter 524 separates and passes the reverse signal 508 received on the port 504 to be amplified by the reverse gain stage 544. The duplex filters and gain stages may be implemented using circuit elements known in RF amplifiers.

[0157] The eAMP circuit 520 may also include circuitry (not shown) for conditioning the forward and reverse RF signals 506, 508, such as automatic gain control (AGC) and / or automatic level / slope control (ALSC) circuitry that provides gain control and / or tilt control. An example of an AGC circuit is described in more detail in U.S. Patent No. 17 / 945,600, now U.S. Patent No. 11,863,145, which are commonly owned and fully incorporated herein by reference.

[0158] One embodiment of the transponder 510 is shown in more detail at Figure 5B The transponder 510 may be implemented as a daughter board in the RF amplifier 500 and connected to a microcontroller unit (MCU) 530 in the RF amplifier 500. The transponder 510 is also coupled to electrical paths 526, 528 that carry the downstream and upstream RF signals 506, 508, respectively.

[0159] In this embodiment, the transponder 510 includes an RF transceiver 512 that sends and receives spread spectrum modulated signals used in low data rate, low power bidirectional transmission. The RF transceiver 512 can be coupled to the MCU 530 in the RF amplifier 500 via a fast SPI interface. The RX matching circuit 514 couples the RX input of the RF transceiver 512 to the downstream RF path 526, and the TX matching circuit 516 and the frequency down converter 518 couple the TX output of the RF transceiver 512 to the upstream RF path 528. The frequency down converter 518 can be an ADI low power active mixer to convert the frequency down to the upstream frequency band. Examples of the RF transceiver 512 include the LoRa (long range), lower power, sub-GHz RF transceiver, SX1261 and LLCC68 available from Semtech. The transponder 510 can also include a temperature compensated crystal oscillator (TXCO) 519 to ensure frequency stability over temperature.

[0160] In this embodiment, the RF amplifier 500 may be a smart amplifier for the MCU 530 and other circuits to monitor and / or control the amplifier, such as by adjusting attenuation and tilt. The smart amplifier may also allow local configuration and control via a USB or wireless interface. If the RF amplifier 500 is a smart amplifier, the transponder 510 may be used to send and receive amplifier data and commands to remotely monitor, control and / or configure the amplifier 500 from the head end. Transmitted from the transponder 510 in the RF amplifier 500 to the head end may include, but are not limited to, AC current consumption, DC current consumption, DC voltage level, amplifier temperature, normal operation time, alarm conditions (possibly configured by the customer), and operating RF conditions, such as output RF power and tilt in both downstream and upstream directions. The commands transmitted from the head end to the transponder 510 in the RF amplifier 500 may include, but are not limited to, status requests, changes in output power, changes in output tilt, requests for diagnostic operations, such as muting of the upstream port to help isolate a problem portion of the amplifier cascade.

[0161] Thus, transponder 510 can report all buffers in amplifier 500 and can cause MCU 530 to change operating parameters of the amplifier, such as to comply with the SCTE-279 specification. Alternatively or additionally, similar transponders can be implemented in nodes of the HFC network, such as node 214 in HFC network 200 or node 314 in HFC network 300, to provide monitoring and / or control of similar nodes.

[0162] Figures 6 to 9 Draw the LoRa network architecture ( Figure 6 ),protocol( Figure 7 as well as Figure 8 ) and packet formats ( Fig. 9 ), which is applicable to some of the above embodiments to provide low data rate, low power bidirectional transmission. LoRa (Long Range) is a long-distance, low data rate, low power wireless platform technology used to build IoT networks. Figure 6 as well as Figure 7 As shown, LoRa uses unlicensed radio spectrum in the Industrial Scientific and Medical (ISM) band to enable communication between remote sensors / devices 610 and gateways 612 connected to network servers 614 and application servers 616. Although LoRa was developed for wireless transmission and IoT networks, LoRa technology can be advantageously used to provide low data rate, low power bidirectional transmission through physical communication media (such as coaxial cable and optical fiber in HFC networks) without causing detectable interference to the main signals on such HFC networks (such as downstream and upstream CATV signals). The above-mentioned low data rate, low power bidirectional transmission can be implemented using the LoRa technology described below but is not necessarily limited to the details described below.

[0163] like Figure 6 As shown, the LoRa network uses a star topology where end nodes or end devices 610 can send messages to multiple gateways 612 that communicate with a network server 614. Because the end device 610 does not belong to a specific gateway, multiple gateways 612 can receive messages sent by the end device 610. LoRa radio access technology is used for communication between the end device 610 and the gateway 612. The gateway 612 and the network server 614 are connected via a standard IP connection.

[0164] The LoRa end device 610 is used to send small amounts of data at low frequencies over long distances. This LoRa transmitted from the end device 610 can be utilized in various applications such as smart cities, smart buildings, factory automation, farm automation, and logistics. The LoRa gateway 612 is a LoRa base transceiver station (BTS) that receives packets from the end node 610 via a radio link and then forwards them to the network server 614 via IP backhaul or 3G / 4G broadband connection. The network server 614 manages the entire network. When the network server 614 receives a packet, it removes the redundancy of the packet and performs a security check and then determines the most suitable gateway 612 to send back a confirmation message. The application server 616 is an end server where all data sent by the end device 610 can be post-processed and can take action.

[0165] Figure 7 The end-to-end network protocol architecture is shown to conform to the LoRa protocol specification developed by the LoRa Alliance. The LoRaWAN protocol includes an application layer 640 and a MAC layer 620 operating on a LoRa physical layer 630. The MAC layer communication between the end device 610 and the network server 614 can be protected by a network session key, and the application layer communication between the end device 610 and the application server 616 can be protected by an application session key. Figure 8 The LoRa protocol stack including a physical layer 630 , a MAC layer 620 , and an application layer 640 is depicted. Fig. 9 The LoRa protocol frame structure for the physical layer 630, the MAC layer 620, and the application layer 640 is shown and will be described in more detail below.

[0166] Physical layer frame 621: At the physical (PHY) layer 630, the LoRa frame 631 begins with a preamble 632. In addition to the synchronization function, the preamble 632 also defines the packet modulation scheme, modulating with the same spreading factor as the rest of the packet. The preamble duration can be 12.25Ts. The preamble 632 is followed by a PHY header that is 20-bits long in total and encoded at the most reliable coding rate, and a header CRC 634, while the rest of the frame is encoded at the coding rate specified in the PHY header 634. The PHY header 634 also contains information such as the payload length and whether the payload 16-bit CRC 638 is present in the frame. In a LoRa network, the uplink frame contains the payload CRC 638. The PHY payload 636 contains the MAC layer frame 621.

[0167] MAC layer frame 621: The MAC layer frame 621 processed in the MAC layer 620 includes a MAC header 622, a MAC payload 624, and a message integrity code (MIC) 626. The MAC header 622 defines the protocol version and the message type, i.e., whether it is a data or management frame, whether it is transmitted in the uplink or downlink, and whether it should be acknowledged. The MAC header 622 may also inform that this is a vendor specific message. In the join process for end node initiation, the MAC payload 624 may be replaced by a join request or join accept message. The entire MAC header 622 and the MAC payload 624 are used to calculate the MIC value 626 using the network session key (Nwk_SKey). The value of the MIC 626 is used to prevent forgery of the message and authenticate the end node.

[0168] Application layer packet 641: MAC payload 624 includes application layer packet 641 processed by application layer 640 including frame header 642, frame port 644 and frame payload 646. The value of frame port 644 is determined according to the application type. Frame payload 646 is encrypted using session key application (App_SKey), and this encryption can be based on AES128 algorithm. In frame header 642, device address 643 includes two parts: the first 8 bits identify the network and the other bits are dynamically allocated during joining the network and identify the device in the network. Frame control 645 includes 1 byte for network control information, such as whether to use the data rate specified by the gateway for uplink transmission, whether this message confirms the receipt of the previous message, and whether the gateway has more data for the remote device. Frame counter 647 is used for sequence numbering. Frame option 649 is a command to change the data rate, transmit power, and connection verification.

[0169] LoRa is a spread spectrum modulation scheme that is a derivative of linear spread spectrum (CSS) modulation and trades data rate for sensitivity within a fixed channel bandwidth. LoRa uses orthogonal spreading factors to implement variable data rates, allowing system designers to trade data rate for range or power to optimize network performance at a constant bandwidth.

[0170] SNR (Signal to Noise Ratio) is the minimum ratio of the desired signal power to the noise that can be demodulated. For receiver sensitivity calculations, the minimum SNR value is determined so that the information can be correctly decoded. The performance of the LoRa modulation itself, the forward error correction (FEC) technology, and the spread spectrum processing gain phase allow for significant SNR improvements. This SNR value depends on the spread factor.

[0171] LoRa uses an unconventional definition of spreading factor as the base 2 logarithm of the number of chirps per symbol. In LoRa, the chirp rate is based on the bandwidth, i.e., the chirp rate is equal to the bandwidth (one chirp per second per hertz of bandwidth). In general, a lower spreading factor results in a higher data rate but lower range and a higher spreading factor results in a lower data rate but higher range.

[0172] Some example SNRs for LoRa modulation formats are shown in the table below.

[0173]

[0174]

[0175] LoRa modulation is a PHY layer implementation that provides significant link budget improvements over traditional narrowband modulation. In addition, the enhanced robustness and selectivity provided by spread spectrum modulation enables greater transmission distances.

[0176] Fig.10 An example is shown where a spread spectrum signal (e.g., a LoRa signal) may be located in frequency relative to a main signal (e.g., a QAM channel in a CATV network). As shown in this example, the spread spectrum signal may be located in a relatively small frequency gap between multiple QAM channels, and the spread spectrum signal bandwidth may be adjusted to be less than 150KHz and approximately 15dB lower in amplitude than the QAM signal level. Thus, a spread spectrum signal (e.g., a LoRa signal) may be inserted between any multiple QAM channels (e.g., between 150MHz and 960MHz). For OFDM channels that do not have frequency gaps, one of the multiple channels may be turned off to insert the spread spectrum signal.

[0177] In other embodiments, the spread spectrum signal may be inserted below the lowest frequency channel used for the main signal. For example, in a CATV system, the spread spectrum signal may be inserted below 258 MHz for the downstream signal. For the upstream signal in a CATV system, the spread spectrum signal may be inserted below 10 MHz, in the middle of the FM broadcast band (88 MHz to 108 MHz), or above 204 MHz. Other locations of the spread spectrum signal relative to the main signal are also possible to achieve transmission without detectable interference.

[0178] Thus, low data rate, low power bidirectional transmission can be achieved through existing physical communication media (e.g., coaxial cable and optical fiber) using spread spectrum signals (e.g., LoRa signals) without detectably interfering with higher bandwidth main signals currently transmitted on the physical communication media. Such low data rate, low power transmission can be advantageously used in HFC networks to transmit commands and / or data to and from network devices to monitor and / or control network devices. Using a portable network communication module to provide such bidirectional transmission further allows monitoring and control of network devices from various locations within the HFC network (e.g., from an HFC node).

[0179] Although the principles of the present invention have been described herein, it should be understood by those skilled in the art that the description is for exemplary purposes only and is not intended to limit the scope of the present invention. In addition to the exemplary embodiments shown and described herein, other embodiments are contemplated within the scope of the present invention. Changes and modifications made by those skilled in the art are considered to be within the scope of the present invention.

Claims

1. A method of communicating with a radio frequency amplifier in a hybrid fiber coaxial network comprising a head end, at least one hybrid fiber coaxial node coupled to the head end by an optical fiber, and a coaxial cable distribution network comprising a plurality of coaxial cables and a plurality of radio frequency amplifiers coupled to the plurality of coaxial cables, characterized in that: At least one of the plurality of RF amplifiers and / or the at least one node comprises a transponder and the headend comprises a gateway device, comprising: sending a downstream main signal from the headend to the coaxial cable distribution network, wherein the downstream main signal is amplified by the radio frequency amplifier; sending an upstream main signal from the coaxial cable distribution network to the headend, wherein the upstream main signal is amplified by the radio frequency amplifier; Connecting a portable network communication module to the hybrid fiber coaxial node; as well as A bidirectional transmission is established between at least one of the plurality of transponders and the portable network communication module for sending a downstream control signal from the portable network communication module to at least one of the plurality of transponders and / or for sending an upstream data signal from at least one of the plurality of transponders to the portable network communication module, wherein the bidirectional transmission uses a spread spectrum modulated signal on the coaxial cable and downstream and upstream main signals, wherein the spread spectrum modulated signal used for the bidirectional transmission has a lower data rate and lower power than the downstream and upstream main signals and is positioned in frequency relative to the downstream and upstream main signals so that the bidirectional transmission occurs without detectable interference with the downstream and upstream main signals.

2. The method according to claim 1, characterized in that The portable network communication module is connected to a test point in the hybrid fiber coaxial node.

3. The method according to claim 1, characterized in that The method further includes connecting a user interface device to the portable network communication module.

4. The method according to claim 1, characterized in that The hybrid fiber-coaxial network is a CATV network, and wherein the downstream main signal includes video and IP data transmitted via a CATV downstream channel spectrum to subscriber devices coupled to the coaxial distribution network.

5. The method according to claim 1, characterized in that The downstream main signal and the upstream main signal are modulated using quadrature amplitude modulation and multiplexed using orthogonal frequency division multiplexing.

6. The method according to claim 1, characterized in that The spread spectrum modulated signal is modulated using Gaussian frequency shift keying.

7. The method according to claim 1, characterized in that The spread spectrum modulated signal is a linear spread spectrum modulated signal.

8. The method according to claim 1, characterized in that The spread spectrum modulated signal is generated according to the LoRaWAN specification.

9. The method according to claim 1, characterized in that The downstream amplifier control signal is located between a plurality of channels for the downstream main signal.

10. The method according to claim 1, characterized in that The downstream amplifier control signal is located below the lowest frequency channel for the downstream main signal.

11. The method according to claim 1, characterized in that The upstream amplifier data signal is located between a plurality of channels for the upstream main signal.

12. The method according to claim 1, characterized in that The upstream amplifier data signal is located below the lowest channel for the upstream main signal.

13. A portable network communication module for use in a hybrid fiber-coaxial network including a coaxial cable distribution network, characterized in that: The portable network communication module includes: a computing device; a gateway processor coupled to the computing device; and At least one gateway transceiver is coupled to the gateway processor and is used to send downstream control signals and to receive upstream data signals, wherein the downstream control signal and the upstream data signal are spread spectrum modulated signals that can be transmitted on the coaxial cable distribution network together with downstream and upstream main signals, wherein the spread spectrum modulated signal has a lower data rate and lower power than the downstream and upstream main signals and is positioned in frequency relative to the downstream and upstream main signals so that bidirectional transmission of the spread spectrum signal occurs without detectable interference with the downstream and upstream main signals.

14. The portable network communication module according to claim 13, wherein: The computing device is used for wireless communication with a user interface device.

15. The portable network communication module according to claim 13, wherein: The at least one gateway transceiver is used to send and receive signals via a test point in a hybrid fiber coaxial node.

16. The portable network communication module according to claim 13, wherein: Further included is a power supply for powering the computing device, the gateway processor, and the at least one gateway transceiver.

17. The portable network communication module according to claim 13, wherein: The portable network communication module is used to connect to a test point in a hybrid fiber-coaxial node in the hybrid fiber-coaxial network, and the computing device is used to collect and store information from the RF amplifier downstream of the hybrid fiber-coaxial node in the hybrid fiber-coaxial network and to format instructions to be sent to the RF amplifier downstream of the hybrid fiber-coaxial node in the hybrid fiber-coaxial network.

18. The portable network communication module according to claim 13, wherein: The spread spectrum modulated signal is modulated using Gaussian frequency shift keying.

19. The portable network communication module according to claim 13, wherein: The spread spectrum modulated signal is a linear spread spectrum modulated signal.

20. The portable network communication module according to claim 13, wherein: This gateway processor complies with the LoRaWAN specification.

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