Patent Application
20250023640
Hybrid fiber-coaxial (HFC) networks, in the upstream direction, are multipoint-to-point networks. Multiple customer premises equipment (CPE), such as cable modems, connect to a passive device, such as a tap, that combines any signals received from cable modems connected to the tap onto a coaxial distribution cable that is coupled to an upstream aggregation node. Because the tap is a passive device, communications from the cable modems that are coupled to the tap are scheduled such that no two modems are concurrently transmitting information. In the downstream direction, the tap splits the signal received on the distribution coaxial cable and sends the signal to each cable modem coupled to the tap, and each cable modem determines what data is destined for the respective cable modem.
In one embodiment a system is provided. The system includes a first fiber-to-coaxial tap device (FTD) that includes a first plurality of coaxial connectors, the coaxial connectors operable to be communicatively coupled to corresponding ones of a first plurality of subscriber cable modems via a corresponding plurality of drop coaxial cables. The first FTD further includes a first fiber connector, operable to be coupled to a fiber node via a first fiber cable, and processing circuitry, operable to receive, via each coaxial connector of the first plurality of coaxial connectors, first radio frequency (RF) signals originating from a corresponding originating subscriber cable modem, convert the first RF signals to first digital packets, wherein each first digital packet includes a first source address that corresponds to the corresponding originating subscriber cable modem, and transmit the first digital packets to the fiber node via first optical signals.
In another embodiment a method is provided. The method includes receiving, at a fiber-to-coaxial tap device (FTD) including a plurality of coaxial connectors communicatively coupled to corresponding ones of a plurality of subscriber cable modems via a corresponding plurality of drop coaxial cables, via each coaxial connector of the plurality of coaxial connectors, first radio frequency (RF) signals originating from a corresponding originating subscriber cable modem, wherein the FTD is communicatively coupled to a fiber node via a fiber cable. The method further includes converting the first RF signals to first digital packets, wherein each first digital packet includes a first source address that corresponds to the corresponding originating subscriber cable modem. The method further includes transmitting the first digital packets to the fiber node via optical signals.
In another embodiment another method is provided. The method includes accessing a coaxial tap including a housing that forms an internal volume, a first coaxial connector coupled to an upstream node via a coaxial distribution cable, and a plurality of second coaxial connectors, the second coaxial connectors communicatively coupled to corresponding ones of a plurality of subscriber cable modems via a corresponding plurality of drop coaxial cables. The method further includes installing, in the internal volume, processing circuitry operable to receive, via each drop coaxial cable of the plurality of drop coaxial cables, radio frequency (RF) signals originating from a corresponding subscriber cable modem, convert the RF signals to digital packets, wherein each digital packet includes a source address that corresponds to the corresponding subscriber cable modem, and transmit the digital packets to a fiber node via the fiber cable via optical signals. The method further includes connecting, to the processing circuitry, a fiber cable and the plurality of drop coaxial cables.
In another embodiment another method is provided. The method includes locating a coaxial tap including a housing, a first coaxial connector coupled to an upstream node via a coaxial distribution cable, and a plurality of second coaxial connectors, the second coaxial connectors communicatively coupled to corresponding ones of a plurality of subscriber cable modems via a corresponding plurality of drop coaxial cables. The method further includes disconnecting the drop coaxial cables from the second coaxial connectors. The method further includes replacing the coaxial tap with a fiber-to-coaxial tap device (FTD) that includes a plurality of third coaxial connectors and a fiber connector operable to be coupled to a fiber node via a fiber cable. The method further includes connecting the drop coaxial cables to the plurality of third coaxial connectors and connecting the fiber cable to the fiber connector.
Individuals will appreciate the scope of the disclosure and realize additional aspects thereof after reading the following detailed description of the examples in association with the accompanying drawing figures.
The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.
The examples set forth below represent the information to enable individuals to practice the examples and illustrate the best mode of practicing the examples. Upon reading the following description in light of the accompanying drawing figures, individuals will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.
Any flowcharts discussed herein are necessarily discussed in some sequence for purposes of illustration, but unless otherwise explicitly indicated, the examples are not limited to any particular sequence of steps. The use herein of ordinals in conjunction with an element is solely for distinguishing what might otherwise be similar or identical labels, such as “first message” and “second message,” and does not imply an initial occurrence, a quantity, a priority, a type, an importance, or other attribute, unless otherwise stated herein. The term “about” used herein in conjunction with a numeric value means any value that is within a range of ten percent greater than or ten percent less than the numeric value. As used herein and in the claims, the articles “a” and “an” in reference to an element refers to “one or more” of the element unless otherwise explicitly specified. The word “or” as used herein and in the claims is inclusive unless contextually impossible. As an example, the recitation of A or B means A, or B, or both A and B. The word “data” may be used herein in the singular or plural depending on the context. The use of “and/or” between a phrase A and a phrase B, such as “A and/or B” means A alone, B alone, or A and B together.
Hybrid fiber-coaxial (HFC) networks, in the upstream direction, are multipoint-to-point networks. Multiple customer premises equipment (CPE), such as cable modems, connect to a passive device, such as a tap, which combines any signals received from cable modems connected to the tap onto a coaxial distribution cable that is coupled to an upstream aggregation node. Because the tap is a passive device, communications from the cable modems that are coupled to the tap are scheduled such that no two modems are concurrently transmitting information. In the downstream direction, the tap splits the signal received on the distribution coaxial cable and sends the signal to each cable modem coupled to the tap, and each cable modem determines what data is destined for the respective cable modem.
The embodiments disclosed herein transform a multipoint-to-point HFC network into a point-to-point HFC network using existing coaxial drop cables that extend between a subscriber's cable modem and a tap, eliminating the tree-and-branch architecture of a conventional HFC network. In particular, the passive tap currently used to combine transmissions from multiple subscriber cable modems is replaced with a fiber-to-coaxial tap device (FTD) that implements functionality similar to a Remote PHY device (RPD) that converts radio frequency (RF) signals received from the subscriber cable modems to packetized data, and sends the packetized data to a fiber node via a fiber cable. The FTD receives packetized data from the fiber node destined for the subscriber cable modems, converts the packetized data to RF signals, and sends the RF signals to the appropriate subscriber cable modems. Because the FTD has separate connections to each subscriber cable modem and packetizes the RF signals received from the subscriber cable modems, the subscriber cable modems can transmit data concurrently and no longer need to wait for specific time and/or frequency slots in which to send data. Similarly, the communications from the fiber node no longer need to be scheduled in particular time and/or frequency slots because the FTD receives digital packets that identify a destination cable modem, and the FTD can convert the data to RF signals and send the RF signals to the particular cable modem to which the packet is addressed.
Among other advantages, the disclosed point-to-point HFC network eliminates losses introduced by RF splitters and amplifiers that would otherwise be necessary in an HFC network, and provides a point-to-point network from the cable modem termination system (CMTS) to each subscriber cable modem, greatly increasing the bandwidth available to the subscriber cable modem without incurring the relatively high costs of installing fiber cables directly to each subscriber's home.
The distribution coaxial cable 26 is coupled to a plurality of taps 28-1-28-4 (generally, taps 28). The tap 28-1 includes a plurality of coaxial connectors 30-1-30-4 that are coupled to drop coaxial cables 32-1-32-4 that are in turn connected to corresponding subscriber cable modems 24-1-24-4. The tap 28-1 includes passive (i.e., unpowered) circuitry 36 that is operable to split a downstream RF signal received from the fiber-to-coaxial device 20 and direct the signal to each of the subscriber cable modems 24-1-24-4 via the drop coaxial cables 32-1-32-4. The circuitry 36 is also operable to receive any RF signals originating from a subscriber cable modem 24-1-24-4 via the corresponding drop coaxial cable 32-1-32-4 and combine the RF signals onto the distribution coaxial cable 26. At some point along the distribution coaxial cable 26, an amplifier 42 may be inserted to ensure sufficient signal strength for additional downstream taps 28.
The subscriber cable modems 24 are typically located in residential or business premises 38 located on corresponding parcels of land 40. One or more of the taps 28 may be located on one of the parcels of land 40 containing a premises 38 served by the respective tap 28. The drop coaxial cables 32 are typically relatively short runs of coaxial cable, such as 50 feet, 100 feet, 200 feet, or the like. The drop coaxial cables 32 may extend between a corresponding subscriber cable modem 24 and the tap 28 without any amplifiers or other splitters between the corresponding subscriber cable modem 24 and the tap 28.
It is noted that for purposes of illustration only a single distribution coaxial cable 26 is illustrated, but in practice the fiber-to-coaxial device 20 may be connected to any number of distribution coaxial cables 26, and the CMTS 12 may be coupled to any number of fiber-to-coaxial devices 20. Moreover, there may be any number of CMTSs 12, and the number of subscriber cable modems 24 may number in the millions.
Because the taps 28 are passive devices that simply combine signals received from the cable modems 24 onto the distribution coaxial cable 26, concurrent transmissions in time or frequency from two or more cable modems will collide corrupting the individual transmissions. To prevent collisions, the CMTS 12 includes a scheduler 44 that provides each cable modem 24 time and/or frequency slots in which RF data will be provided to the cable modem 24 and time and/or frequency slots in which the cable modem 24 can send RF data to the CMTS 12. The taps 28-2-28-4 are configured identically or substantially similarly as the tap 28-1 and provide identical or substantially similar functionality to corresponding cable modems 24 as described above with regard to the tap 28-1.
The FTD 52-1 includes powered circuitry 56 that includes a processor device and a memory, and is operable to receive, via each coaxial connector 54, RF signals originating from a corresponding subscriber cable modem 24, convert the RF signals to digital packets, wherein each digital packet includes a source address that corresponds to the corresponding originating subscriber cable modem 24, and transmit the digital packets to the fiber node 48 via optical signals. The term “digital” as used herein refers to binary data that is communicated by two different states, such as two different signal levels. The RF signals may include packets that contain the source address.
The powered circuitry 56 is operable to receive a digital packet from the fiber node 48 addressed to a subscriber cable modem 24 of the plurality of subscriber cable modems 24-1-24-4 connected to the FTD 52-1, convert the digital packet to RF signals, and transmit the RF signals to the subscriber cable modem 24 based on the destination address identified in the packet. Notably, the powered circuitry 56 sends the RF signals only to the subscriber cable modem 24 of the plurality of subscriber cable modems 24-1-24-4 to which the packet is addressed.
It is noted that, while the powered circuitry 56 is, solely for purposes of illustration, illustrated separately from the fiber connectors 55 and the coaxial connectors 54, in some embodiments, the powered circuitry 56 is integrated with the fiber connectors 55 and the coaxial connectors 54, such as on a printed circuit board or the like.
The powered circuitry 56 may include, by way of non-limiting example, downstream quadrature amplitude modulation (QAM) and orthogonal frequency-division multiplexing (OFDM) modulators, upstream QAM and OFDM demodulators, and pseudowire logic used to connect to a Converged Cable Access Platform (CCAP) Core. The powered circuitry 56 may be operable to convert downstream DOCSIS data, MPEG video, and out-of-band (OOB) signals received from a CCAP Core over a digital fiber network such as Ethernet or passive optical network (PON) to analog RF for transmission over the coaxial cable; and to convert upstream RF, DOCSIS, and OOB signals received over the coaxial cable to digital for transmission over Ethernet or PON to a CCAP Core.
The FTD 52-1 may be located on one of the parcels of land 40 of the plurality of parcels of land 40 containing a premises 38 served by the FTD 52-1. Because the FTD 52-1 processes the connections with the subscriber cable modems 24-1-24-4 independent of one another and converts all RF signals received from the subscriber cable modems 24-1-24-4 to digitized packets, each of the subscriber cable modems 24-1-24-4 can transmit RF signals to the FTD 52-1 concurrently with the other subscriber cable modems 24-1-24-4 without fear of collisions. Thus, each of the subscriber cable modems 24-1-24-4 can communicate concurrently and independently with the fiber node 48 thus establishing point-to-point connections 58-1-58-4 between the subscriber cable modems 24-1-24-4 and the fiber node 48 via the FTD 52-1. Moreover, because the subscriber cable modems 24-1-24-4 can communicate concurrently and independently with the fiber node 48, the CMTS 12-1 does not need a scheduler in order to ensure that the subscriber cable modems 24-1-24-4 schedule transmissions in dedicated time and/or frequency slots to avoid collisions.
In some embodiments, the FTD 52-1 includes a plurality of fiber connectors 55 equal in number to the number of coaxial connectors 54, each fiber connector 55 being operable to be coupled to an individual strand of fiber of the fiber cable 50. The powered circuitry 56 is operable to utilize, for each respective subscriber cable modem 24-1-24-4, a particular fiber strand for all communications originating from or destined to the respective subscriber cable modem 24-1-24-4.
In some embodiments, the powered circuitry 56 is operable to transmit digital packets from different cable modems 24 to the fiber node 48 on a single strand of fiber concurrently using different wavelengths that correspond to the subscriber cable modems 24-1-24-4. In some embodiments, the powered circuitry 56 may send the generated digital packets to the fiber node 48 on a single wavelength on a single strand of fiber.
In some embodiments, the FTD 52-1 includes a device that complies with a DOCSIS 3.0, DOCSIS 3.1, or DOCSIS 4.0 specification. The drop coaxial cables 32-1-32-4 may extend between the corresponding cable modem 24-1-24-4 and the FTD 52-1 without any amplifiers or other splitters between the corresponding cable modem 24 and the FTD 52-1.
The FTDs 52-2-52-4 are configured identically or substantially similarly as the FTD 52-1 and provide identical or substantially similar functionality to corresponding cable modems 24 as described above with regard to the FTD 52-1.
Referring again to
The system bus 64 may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and/or a local bus using any of a variety of commercially available bus architectures. The system memory 62 may include non-volatile memory 66 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory 68 (e.g., random-access memory (RAM)). A basic input/output system (BIOS) 70 may be stored in the non-volatile memory 66 and can include the basic routines that help to transfer information between elements within the FTD 52-1. The volatile memory 68 may also include a high-speed RAM, such as static RAM, for caching data.
The FTD 52-1 may further include or be coupled to a non-transitory computer-readable storage medium such as a storage device 71, which may comprise, for example, an internal hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), HDD (e.g., EIDE or SATA) for storage, flash memory, or the like. The storage device 71 and other drives associated with computer-readable media and computer-usable media may provide non-volatile storage of data, data structures, computer-executable instructions, and the like.
A number of modules can be stored in the storage device 71 and in the volatile memory 68, including an operating system and one or more program modules which may implement the functionality described herein in whole or in part. All or a portion of the examples may be implemented as a computer program product 72 stored on a transitory or non-transitory computer-usable or computer-readable storage medium, such as the storage device 71, which includes complex programming instructions, such as complex computer-readable program code, to cause the processor device 60 to carry out the steps described herein. Thus, the computer-readable program code can comprise software instructions for implementing the functionality of the examples described herein when executed on the processor device 60.
As noted above, the powered circuitry 56 may include downstream QAM and OFDM modulators, upstream QAM and OFDM demodulators, and pseudowire logic used to connect to a CCAP Core. The powered circuitry 56 may be operable to convert downstream DOCSIS data, MPEG video, and out-of-band (OOB) signals received from a CCAP Core over a digital fiber network such as Ethernet or passive optical network (PON) to analog RF for transmission over the coaxial cable; and to convert upstream RF, DOCSIS, and OOB signals received over the coaxial cable to digital for transmission over Ethernet or PON to a CCAP Core. The FTD 52-1 includes one or more coaxial connectors 54 and one or more fiber connectors 55.
Individuals will recognize improvements and modifications to the preferred examples of the disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.
