Patent Publication Number: US-2020304278-A1

Title: Architecture for combining full-duplex and frequency division duplex communication systems

Description:
TECHNICAL FIELD 
     The present disclosure relates to content distribution systems, and more particularly, but not exclusively, to an architecture for combining full-duplex and frequency division duplex communication systems. 
     BACKGROUND 
     Modern cable television (CATV) systems provide not only one-way broadcast programming, but also high-speed two-way communications between customers and the Internet. Cable modems are a primary source of Internet connectivity for millions of consumers worldwide, backhauling local WiFi communications for residential and business customers. Modern high-spectral-efficiency CATV systems, such as those based on the Data Over Cable Service Interface Specification (DOCSIS) 3.1 standard that governs cable communications, increasingly depend on complex signal modulation, with high-order constellations, multi-carrier signaling and multi-channel aggregation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain features of the subject technology are set forth in the appended claims. However, for purpose of explanation, one or more implementations of the subject technology are set forth in the following figures. 
         FIG. 1  illustrates an example network environment in which a content distribution system may be implemented in accordance with one or more implementations of the subject technology. 
         FIG. 2  illustrates an example content distribution system in accordance with one or more implementations of the subject technology. 
         FIG. 3A  conceptually illustrates the layout of a traditional hybrid optical-fiber/coaxial cable CATV distribution architecture in accordance with one or more implementations of the subject technology. 
         FIG. 3B  is a diagram illustrating an example of a communication device operative within one or more communication systems. 
         FIG. 4A  illustrates an example of a continuous multicarrier spectrum based on a frequency division duplex communication system in accordance with one or more implementations of the subject technology. 
         FIG. 4B  illustrates an example architecture for a frequency division duplex communication system in accordance with one or more implementations of the subject technology. 
         FIG. 5A  illustrates an example of a continuous multicarrier spectrum based on a full-duplex communication system in accordance with one or more implementations of the subject technology. 
         FIG. 5B  illustrates an example architecture for a full-duplex communication system in accordance with one or more implementations of the subject technology. 
         FIG. 6A  illustrates an example of a continuous multicarrier spectrum based on a combination of full-duplex and frequency division duplex communication systems in accordance with one or more implementations of the subject technology. 
         FIG. 6B  illustrates an example architecture for combining full-duplex and frequency division duplex communication systems in accordance with one or more implementations of the subject technology. 
       FIB.  6 C illustrates another example architecture for combining full-duplex and frequency division duplex communication systems in accordance with one or more implementations of the subject technology. 
         FIG. 7  conceptually illustrates an electronic system with which any implementations of the subject technology are implemented. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be clear and apparent to those skilled in the art that the subject technology is not limited to the specific details set forth herein and may be practiced using one or more implementations. In one or more instances, structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. 
     In a content distribution system defined by the DOCSIS 3.1 standard, significant challenges exist when Full-Duplex (FDX) and Frequency Division Duplex (FDD) communication systems are combined. For example, any components of the content distribution system such as a frequency-domain multiplexing device in the FDD communication system that causes transmitter signal reflection severely limits the signal-to-noise performance that can be achieved in the FDX communication system. 
     To address this challenge, the present disclosure provides for an architecture that combines the FDD and FDX communication systems that maximizes the signal-to-noise ratio (SNR) of the FDX transmission without being affected by the input reflection of any filtering components in the FDX signal path. The architecture of the subject technology reduces the design complexity required for a transmitter by reducing the number of power amplifiers utilized and reducing the input return loss of the FDX/FDD communication system. In the subject technology, the architecture includes a coupler coupled to a terminal and configured to allow duplex transmissions of digital signals via the terminal. The subject architecture includes a filtering device coupled to the coupler and configured to divide a downstream signal received through the coupler into a plurality of downstream signals associated with a plurality of frequency ranges. The subject architecture includes a transmitter coupled to the coupler and configured to drive, through the coupler, an upstream signal comprising digital signals associated with the plurality of frequency ranges. The subject architecture also includes a plurality of receivers coupled to the filtering device and configured to receive respective ones of the plurality of downstream signals. 
       FIG. 1  illustrates an example network environment  100  in which a content distribution system may be implemented in accordance with one or more implementations. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     The example network environment  100  includes a headend  105 , an optical line terminal (OLT)  110 , buildings  120 A-D, media converters  135 A-D, a first transmission network  115 , and second transmission networks  125 A-D. The buildings  120 A-D may be multi-dwelling units (MDUs), houses, offices, or any general structures. In one or more implementations, one or more of the buildings  120 A-D may represent a collection of separate structures, such as a subdivision of separate houses. In one or more implementations, the media converters  135 A-D generally refer to “fiber nodes,” where a transmission media over fiber is redistributed to a transmission media over coaxial cable, and vice versa. 
     The buildings  120 A-D may include multiple gateway devices that are located in different units of the buildings  120 A-D, such as different offices, different dwelling units, etc. The gateway devices may be coupled to the media converters  135 A-D via the second transmission networks  125 A-D and may be coupled to one or more user devices within the different units via local area networks. The second transmission networks  125 A-D may include network couplings and/or adapters, such as splitters, and may include any network medium, such as coaxial transmission lines, fiber optic transmission lines, Ethernet transmission lines, power transmission lines, etc. In one or more implementations, the second transmission networks  125 A-D may include a non-optical network medium, such as coaxial transmission lines. 
     In the network environment  100 , the second transmission network  125 A is represented as a DOCSIS network that includes coaxial transmission lines, the second transmission network  125 B is represented as a Ethernet over Coxial (EoC) network that includes coaxial transmission lines, the second transmission network  125 C is represented as part of a fiber to the home (FTTH) network that includes fiber optic transmission lines, and the second transmission network  125 D is represented as a local area network (LAN) that includes Ethernet transmission lines. 
     The media converters  135 A-D may be coupled to the gateway devices via the second transmission networks  125 A-D and may be coupled to the OLT  110  via the first transmission network  115 . The first transmission network  115  may include one or more network couplings, or adapters, such as splitters, and may include any network medium, such as coaxial transmission lines, fiber optic transmission lines, Ethernet transmission lines, power transmission lines, etc. In one or more implementations, the first transmission network  115  may include an optical network medium and one or more optical splitters. In one or more implementations, the second network medium may be different than the first network medium. In the network environment  100 , the first transmission network  115  is represented as a passive optical network (PON) that includes fiber optic transmission lines. 
     Since the media converters  135 A-D are coupled to the gateway devices via the second transmission networks  125 A-D, and to the OLT  110  via the first transmission network  115 , the media converters  135 A-D may convert signals received over the first transmission network  115 , such as optical signals, to signals that can be transmitted over the second transmission networks  125 A-D, such as electric signals. In one or more implementations, the media converters  135 A-D may act as layer-2 bridges, which receive data packets from the OLT  110  of the headend  105  over optical network medium of the first transmission network  115 , and bridge the received data packets over the non-optical network medium of the second transmission networks  125 A-D to the gateways, and vice-versa. 
     The headend  105  may include one or more devices, such as network devices, transmitters, receivers, servers, etc., that are part of a content delivery network (CDN) that coordinates the delivery of content items, such as television programs, movies, songs or other audio programs, educational materials, community information, or generally any content items, to the user devices of the buildings  120 A-D. The content items may be delivered to the user devices via any content delivery mechanism. The headend  105  may use the OLT  110  to communicate over the first transmission network  115  with the media converters  135 A-D. 
     The media converters  135 A-D and the gateway devices may each include local caches, such as hard drives or other memory devices, for storing content items received from the headend  105  that are intended for distribution to the user devices. For example, the headend  105  may transmit content items that are expected to be requested by the user devices, such as popular movies, television shows, etc., to the media converters  135 A-D and/or the gateway devices during off-peak hours. For example, if the headend  105  determines that there is a popular television series for which a not-yet-aired episode is expected to be requested by many of the user devices when the episode airs (or otherwise becomes available), the headend  105  may transmit the not-yet-aired episode to one or more of the media converters  135 A-D and/or one or more of the gateways during off-peak hours, such as the night before the episode is scheduled to air (or otherwise become available). In this manner, the simultaneous viewing of the episode by many of the user devices the next day will not overwhelm the first transmission network  115  and/or the second transmission networks  125 A-D. Similarly, if a user device is accessing an episode television series on-demand, the headend  105  can coordinate caching one or more subsequent episodes to a media converter  135 A and/or a gateway device that is upstream from the user device. 
     In one or more implementations, the headend  105  may receive an indication from a third party server, such as a content provider server, that a particular content item is expected to be requested by multiple user devices. For example, the headend  105  may receive an indication from an audio content provider that an upcoming release of a song and/or album of a certain artist or style is expected to be requested by many of the user devices. The headend  105  may then transmit the song and/or album to the media converters  135 A-D and/or the gateway devices in advance of the release date, such as the night before, e.g. an during off-peak, or low traffic, time period. 
       FIG. 2  illustrates an example content distribution system  200  in accordance with one or more implementations. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     The example content distribution system  200  includes the headend  105 , the OLT  110 , the buildings  120 A-C, the first transmission network  115  and the second transmission networks  125 A-C. The buildings  120 A-C include utility areas  210 A-C and units  220 A-I. The units  220 A-I may include gateway devices  225 A-I, electronic devices  222 A-I,  226 A-I,  228 A-I, and display devices  224 A-I. 
     The utility areas  210 A-C may be common areas of the buildings  120 A-C, e.g. areas of the buildings  120 A-C that are accessible to utility operators, such as broadband service providers. In one or more implementations, the utility areas  210 A-C may be in the basement of the buildings  120 A-C or external to the buildings  120 A-C. The units  220 A-I of the buildings  120 A-C may be dwelling units, office spaces, or generally any delineated structures within the buildings  120 A-C. In one or more implementations, one or more of the buildings  120 A-C may represent a collection of physically separate units  220 A-I, such as a subdivision of separate houses. 
     The gateway devices  225 A-I may include a network processor or a network device, such as a switch or a router, that is configured to couple the electronic devices  222 A-I,  226 A-I,  228 A-I to the headend  105  via the media converters  135 A-C. The gateway devices  225 A-I may include local area network interfaces, such as wired interfaces and/or wireless access points, for communicating with the electronic devices  222 A-I,  226 A-I,  228 A-I. The gateway devices  225 A-I may include a local cache for caching content items and/or portions of content items, and the gateway devices  225 A-I may include distribution control modules for coordinating the caching of the content items. 
     The electronic devices  222 A-I,  226 A-I,  228 A-I can be computing devices such as laptop or desktop computers, smartphones, personal digital assistants (“PDAs”), portable media players, set-top boxes, tablet computers, televisions or other displays with one or more processors coupled thereto and/or embedded therein, or other appropriate computing devices that can be used for adaptive bit rate streaming, and rendering, of multimedia content and/or can be coupled to such a device. In the example of  FIG. 2 , the electronic devices  222 A-I are depicted as set-top boxes (STBs) that are coupled to display devices  224 A-I, such as televisions, the electronic devices  226 A-I are depicted as smart phones, and the electronic devices  226 A-I are depicted as tablet devices. In one or more implementations, any of the electronic devices  222 A-I,  226 A-I,  228 A-I may be referred to as a user device and any of the electronic devices  222 A-I,  226 A-I,  228 A-I may be, or may include one or more components of, the electronic system that is discussed below with respect to  FIG. 3 . 
     As shown in  FIG. 2 , the headend  105 , media converters  135 A-C, gateway devices  225 A-I, and electronic devices  222 A-I,  226 A-I,  228 A-I are arranged in a hierarchical tree network arrangement such that the headend  105  is directly coupled to the media converters  135 A-C, the media converter  135 A is directly coupled to the gateway devices  225 A-C, the media converter  135 B is directly coupled to the gateway devices  225 D-F, the media converter  135 C is directly coupled to the gateway devices  225 G-I, the gateway device  225 A is directly coupled to the electronic devices  222 A,  226 A,  228 A, the gateway device  225 B is directly coupled to the electronic devices  222 B,  226 B,  228 B, etc. In other words, the headend  105  is located directly upstream from the media converters  135 A-C, the media converter  135 A is located directly upstream from the gateway devices  225 A-C, the media converter  135 B is located directly upstream from the gateway devices  225 D-F, the media converter  135 C is located directly upstream from the gateway devices  225 G-I, the gateway device  225 A is located directly upstream from the electronic devices  222 A,  226 A,  228 A, the gateway device  225 B is located directly upstream from the electronic devices  222 B,  226 B,  228 B, etc. 
     The media converters  135 A-C and/or the gateway devices  225 A-I, may each include a cache, such as a hard drive or other memory device, that stores content items, and/or portions thereof, intended for distribution from the headend  105  to one or more of the electronic devices  222 A-I,  226 A-I,  228 A-I. Thus, the caching of the content items is distributed across two layers of network nodes in the hierarchical network arrangement, first the media converters  135 A-C and then the gateway devices  225 A-I. If a content item that is cached by a media converter  135 A or a gateway device  225 A is requested by an electronic device  222 A, the content item is provided to the electronic device  222 A by the media converter  135 A or the gateway device, rather than by the headend  105 , thereby conserving upstream bandwidth. 
     The headend  105  may communicate with distribution control modules of the media converters  135 A-C to coordinate caching the content items at the media converters  135 A-C. The distribution control modules of the media converters  135 A-C may also coordinate the caching of content in the subset of the downstream gateway devices  225 A-I that are directly coupled to the media converters  135 A-C. For example, the media converter  135 A may coordinate the caching of content in the gateway devices  225 A-C. The distribution control modules of the media converters  135 A-C may communicate with distribution control modules of the gateway devices  225 A-I to coordinate caching content items at the gateway devices  225 A-I. The headend  105  and the distribution control modules of the media converters  135 A-C and the gateway devices  225 A-I are discussed further below with respect to  FIG. 3 . 
     The headend  105  and/or the distribution control modules of the media converters  135 A-C may control the distribution of the caching such that content items, or portions thereof, that are expected to be requested by one or more of the electronic devices  222 A-I,  226 A-I,  228 A-I are cached at the media converters  135 A-C and/or the gateway devices  225 A-I that service, e.g. are directly upstream from, the electronic devices  222 A-I,  226 A-I,  228 A-I, prior to the content items, or portions thereof, being requested by the electronic devices  222 A-I,  226 A-I,  228 A-I. For example, when an electronic device  222 A requests a content item, or a portion thereof, from the headend  105  that is cached at the gateway device  225 A, or the media converter  135 A, that services the electronic device  222 A, the gateway device  225 A or media converter  135 A can intercept the request, e.g. since the request will be transmitted to the headend  105  via the gateway device  225 A and the media converter  135 A, and the gateway device  225 A or the media converter  135 A can provide the cached content item, or portion thereof, to the electronic device  222 A, instead of transmitting the request back to the headend  105 . In this manner requested content items can be provided to the electronic devices  222 A-I,  226 A-I,  228 A-I from a proximal network node, thereby reducing upstream congestion. 
     In one more implementations, the headend  105 , and/or the distribution control modules of the media converters  135 A-C and/or the gateway devices  225 A-I may collectively maintain a cache directory of cached content items. The cache directory may be locally stored at the headend  105 , and/or at the distribution control modules of one or more of the media converters  135 A-C and/or the gateway devices  225 A-I. The cache directory may include, for example, an identification of each cached content item, or portion thereof, and a network identifier, such as a uniform resource locator (URL), for accessing the content item, or portion thereof. The gateway devices  225 A-I and/or the media converters  135 A-C may utilize content redirection techniques, such as hypertext transport protocol (HTTP) redirection techniques, to allow the electronic devices  222 A-I,  226 A-I,  228 A-I to access content items that are cached at the media converters  135 A-C and/or at the gateway devices  225 A-I that are not directly upstream from the electronic devices  222 A-I,  226 A-I,  228 A-I. 
     For example, a gateway device  225 D and/or a media converter  135 B that are located directly upstream from an electronic device  222 D may intercept a request for a content item, or portion thereof, from the electronic device  222 D. If the requested content item is not cached at the gateway device  225 D or the media converter  135 B, the gateway device  225 D and/or the media converter  135 B may determine, based on the locally stored cache directory, whether the requested content item is cached at another media converter  135 A,C or gateway device  225 A-C, E-I. If the requested content item is cached at another media converter  135 A,C or gateway device  225 A-C, E-I, the gateway device  225 D and/or the media converter  135 B may utilize an HTTP redirection technique to redirect the request of the electronic device  222 D from the headend  105  to the another media converter  135 A,C or gateway device  225 A-C, E-I, such as the media converter  135 A. 
     The headend  105  may partition the electronic devices  222 A-I,  226 A-I,  228 A-I into groups based on the content items that are expected to be requested by the electronic devices  222 A-I,  226 A-I,  228 A-I. For example, the electronic devices  222 A-I,  226 A-I,  228 A-I may be partitioned into groups based on characteristics associated with the electronic devices  222 A-I,  226 A-I,  228 A-I and/or characteristics associated with the users interacting with the electronic devices  222 A-I,  226 A-I,  228 A-I, such as the level of service, e.g. channel tier, accessible to the electronic devices  222 A-I,  226 A-I,  228 A-I, e.g. via subscriptions, the physical locations of the electronic devices  222 A-I,  226 A-I,  228 A-I, the demographics of the users interacting with the electronic devices  222 A-I,  226 A-I,  228 A-I, content items previously accessed by the electronic devices  222 A-I,  226 A-I,  228 A-I, such as episodes of a serial television program, or generally any characteristics that are indicative of content items that may be requested in the future by the electronic devices  222 A-I,  226 A-I,  228 A-I. 
     For a given group of the electronic devices  222 A-I,  226 A-I,  228 A-I, such as the group of the electronic devices  222 A-I,  226 D-F,  228 D-F that can access a particular channel tier, the headend  105  may determine one of the media converters  135 A-C that provides service to, e.g. is directly upstream from, the largest number of the electronic devices  222 A-I,  226 D-F,  228 D-F in the group. Since the media converter  135 B provides service to nine out of fifteen of the electronic devices  222 A-I,  226 D-F,  228 D-F in the group, e.g. the electronic devices  222 D-F,  226  D-F,  228 D-F, the headend  105  may determine the media converter  135 B. 
     Once the media converters  135 A-C receive content items, and/or portions thereof, to be cached from the headend  105 , the distribution control modules of the media converters  135 A-C may identify content items that can be cached downstream at one or more of the gateway devices  225 A-I, such as content items that are only expected to be accessed by a single electronic device  222 A. The media converters  135 A-C may determine that a particular content item is only expected to be accessed by a single electronic device  222 A based at least in part on content access patterns of the electronic devices  222 A-I,  226 D-F,  228 D-F in the group. In one or more implementations, the content access patterns of the electronic devices  222 A-I,  226 D-F,  228 D-F in the group may be determined by one or more of the media converters  135 A-C and/or the gateway devices  225 A-I, by sniffing the network protocol messages that pass through the media converters  135 A-C and/or gateway devices  225 A-I. The distribution control modules of the media converters  135 A-C may coordinate moving these content items from the cache of the media converters  135 A-C to the cache of one or more of the gateway devices  225 A-I. The distribution controllers of the media converters  135 A-C may then coordinate with the distribution server of the headend  105  to receive additional content items, or portions thereof, to cache, e.g. in the cache space vacated by pushing the content item down to the one or more gateway devices  225 A-I. 
     For example, a media converter  135 B may determine that a content item can be cached at one of the gateway devices  225 A-I, such as the gateway device  225 D, when the content item is expected to be primarily accessed by the electronic devices  222 D,  226 D,  228 D that are directly downstream from the gateway device  225 D. In one or more implementations, a content item may be cached at a gateway device  225 D if the content item is expected to be primarily accessed by the electronic devices  222 D,  226 D,  228 D that are directly downstream from the gateway device  225 D, and/or by the electronic devices  222 E-F,  224 E-F,  228 E-F that are directly downstream from the gateway devices  225 E-F that are directly coupled to the gateway device  225 D, e.g. via the second transmission network  125 B. 
     In one or more implementations, distribution control modules of the gateway devices  225 A-I may communicate directly with the headend  105 , e.g. via a distribution control module of one of the media converters  135 A-C, in order to coordinate caching content items on the gateway device that are expected to be accessed by electronic devices  222 A-I,  226 A-I,  228 A-I that are served by the gateway device, such as based on content access patterns of the electronic devices  222 A-I,  226 A-I,  228 A-I. For example, if a gateway device  225 A includes, or is coupled to, a set-top box that is configured to record a television show on a weekly basis, the gateway device  225 A may coordinate with the headend  105  in order to have the television program cached on the gateway device  225 A prior to its air time, e.g. during off-peak hours. Similarly, if an electronic device  222 A is accessing an episode of a television series on-demand via a gateway device  225 A, the gateway device  225 A may coordinate with the headend  105  to cache subsequent episodes of the television series, e.g. during off-peak hours. In one or more implementations, the gateway device  225 A may determine the content access patterns of the electronic devices  222 A,  226 A,  228 A served by the gateway device  225 A by sniffing the network protocol messages that pass through the gateway device  225 A. 
       FIG. 3A  conceptually illustrates the layout of a traditional hybrid optical-fiber/coaxial cable CATV distribution architecture  300  in accordance with one or more implementations of the subject technology. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     A cable modem system is typically housed in a hybrid fiber/coaxial cable distribution architecture, such as the hybrid optical-fiber/coaxial cable CATV distribution architecture  300 . The hybrid optical-fiber/coaxial cable CATV distribution architecture  300  consists of a fiber portion and a coaxial portion. The headend  105  is housed in the fiber portion of the hybrid optical-fiber/coaxial cable CATV distribution architecture  300 . The headend  105  may provide operation of a cable modem termination system (CMTS). For example, the headend  105  may perform such CMTS functionality, or a CMTS  302  may be included in the headend  105  or may be implemented in a remotely distributed architecture between the headend  105  and other network segments. In other implementations, the CMTS  302  may be included in the fiber node (e.g.,  135 ). The CMTS  302  can provide network service (e.g., Internet, other network access, etc.) to any number of cable modems (e.g., the communication devices  304 - 1 ,  304 - 2 ,  304 - 3 ,  304 - 4 ,  304 - 5 ) via a cable modem network segment. The network segment over which the CMTS  302  and the cable modems communicate is referred to as a hybrid optical-fiber/coaxial cable network (e.g., including various wired and/or optical fiber communication segments, light sources, light or photo detection components, etc.). 
     As depicted in  FIG. 3A , the CMTS  302  is located within the headend  105 , and services a plurality of cable modems (e.g., the communication devices  304 - 1 ,  304 - 2 ,  304 - 3 ,  304 - 4 ,  304 - 5 ), located in the coaxial portion of the hybrid fiber/coaxial cable distribution architecture via a plurality of fiber nodes in a point-to-multipoint topology. As depicted in  FIG. 3 , customer-premise cable modems and set-top boxes (e.g., communication devices  304 - 1 ,  304 - 2 ,  304 - 3 ,  304 - 4 ,  304 - 5 ) in a community (e.g., buildings  120 A- 1 ,  120 A- 2 ,  120 A- 3 ,  120 A- 4 ,  120 A- 5 ) communicate with a fiber node  135 A, which is, or includes at least a portion of, the media converter  135 A, via a shared coaxial cable. The fiber node  135 A then communicates two-way traffic with the cable headend  105 , similar in function to the wireline telephone central office. 
     In some implementations, the CMTS  302  may be a component that exchanges digital signals with cable modems on the hybrid fiber/coaxial cable distribution architecture. Each of the cable modems is coupled to the hybrid fiber/coaxial cable distribution architecture, and a number of elements may be included within the hybrid fiber/coaxial cable distribution architecture. For example, routers, splitters, couplers, relays, and amplifiers may be contained within the hybrid fiber/coaxial cable distribution architecture. In some aspects, downstream information may be viewed as that which flows from the CMTS  302  to the connected cable modems, and upstream information as that which flows from the cable modems to the CMTS  302 . 
     Typically, bandwidth is available to transmit signals downstream from the headend  105  to the cable modems, such as the communication devices  304 - 1 ,  304 - 2 ,  304 - 3 ,  304 - 4 ,  304 - 5 . However, in the upstream, bandwidth is limited and is arbitrated among the competing cable modems in the system. Cable modems request bandwidth from the CMTS  302  prior to transmitting data to the headend  105 . The CMTS  302  allocates bandwidth to the cable modems based on availability and the competing demands from other cable modems in the system. The DOCSIS 3.1 standard uses frequency bands of approximately 5-200 MHz and 50-1200 MHz for upstream (customer to headend  105 ) and downstream (headend  105  to customer) signals, respectively. 
       FIG. 3B  is a diagram illustrating an example of a communication device  310  operative within one or more communication systems. In some implementations, the communication device  310  is, or includes at least a portion of, the communication devices  304 - 1 ,  304 - 2 ,  304 - 3 ,  304 - 4 ,  304 - 5 . The communication device  310  includes a communication interface  320  and a processor  330 . The communication interface  320  includes functionality of a transmitter  322  and a receiver  324  to support communications with one or more other devices within a communication system. The communication device  310  may also include memory  340  to store information including one or more signals generated by the communication device  310  or such information received from other devices (e.g., the headend  105  and/or the fiber node  135 A) via one or more communication channels. The memory  340  may also include and store various operational instructions for use by the processor  330  in regards to the processing of messages and/or other received signals and generation of other messages and/or other signals including those described herein. The memory  340  may also store information including one or more types of encoding, one or more types of symbol mapping, concatenation of various modulation coding schemes, etc. as may be generated by the communication device  310  or such information received from other devices via one or more communication channels. The communication interface  320  supports communications to and from one or more other devices (e.g., the headend  105  and/or other communication devices). Operation of the communication interface  320  may be directed by the processor  330  such that processor  330  transmits and receives signals (TX(s) and RX(s)) via the communication interface  320 . 
     In some implementations, the communication interface  320  is implemented to perform any such operations of an analog front end (AFE) and/or physical layer (PHY) transmitter, receiver, and/or transceiver. Examples of such operations may include any one or more of various operations including conversions between the frequency and analog or continuous time domains (e.g., such as the operations performed by a digital to analog converter (DAC) and/or an analog to digital converter (ADC)), gain adjustment including scaling, filtering (e.g., in either the digital or analog domains), frequency conversion (e.g., such as frequency upscaling and or frequency downscaling, such as to a baseband frequency at which one or more of the components of the communication device  310  operates), equalization, pre-equalization, metric generation, symbol mapping and/or de-mapping, automatic gain control (AGC) operations, and/or any other operations that may be performed by an AFE and/or PHY component within a communication device. 
     In some implementations, the communication device  310  includes a frequency diplexer (or alternatively, another filtering device, such as a frequency triplexer) that services both upstream and downstream communications to and from the fiber node  135 A. 
       FIG. 4A  illustrates an example of a continuous multicarrier spectrum  400  based on a frequency division duplex communication system in accordance with one or more implementations of the subject technology. The frequency division duplex communication system uses frequency bands of approximately 5-85 MHz (depicted as FDD RX  410 ) and 108-1218 MHz (depicted as FDD TX  420 ) for downstream (headend  105  to customer) and upstream (customer to headend  105 ) signals, respectively. 
       FIG. 4B  illustrates an example architecture of a frequency division duplex communication system  450  in accordance with one or more implementations of the subject technology. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     The frequency division duplex communication system  450  includes a transmitter  452  (TX), a receiver  454  (RX), and a diplexer  456 . In some implementations, the frequency division duplex communication system  450  is, or includes a portion of, the communication device  310  as depicted in  FIG. 3B . In some aspects, the frequency division duplex communication system  450  includes an F-connector  458 . In some implementations, the F-connector  458  is a coaxial RF connector commonly used for “over the air” terrestrial television, cable television and universally for satellite television and cable modems, usually with RG-6/U cable or, in older installations, with RG-59/U cable. Note that any other type of connector may be used in various applications. In some aspects, the receiver  454  may process, demodulate, decode, and/or interpret signals received via the F-connector  458  and the diplexer  456 . 
     The diplexer  456  services both upstream and downstream communications to and from the fiber node  135 A. The receiver  454  receives and samples signals from the diplexer  456  and may provide them to a processor (e.g.,  330 ) for downstream processing. The received signals for downstream processing may first be filtered by the diplexer  456  to provide received signals within the downstream frequency range (e.g., between 5-85 MHz) and passed on to the receiver  454 . The processor  330  may generate digital signals for upstream transmission, and the transmitter  452  may generate amplified analog or continuous-time signals there from. The digital signals for upstream transmission may be filtered by the diplexer  456  to provide digital signals within the upstream frequency range (e.g., between 108-1218 MHz) to the fiber node  135 A. The transmitter  452  may be implemented as a power amplifier to amplify the analog or continuous-time signals. 
       FIG. 5A  illustrates an example of a continuous multicarrier spectrum  500  based on a full-duplex communication system in accordance with one or more implementations of the subject technology. The full-duplex communication system uses a frequency band of approximately 5-30 MHz (depicted as FDX TX/RX  502 ) for both downstream (headend  105  to customer) and upstream (customer to headend  105 ) signals, transmitted simultaneously. 
       FIG. 5B  illustrates an example architecture of a full-duplex communication system  510  in accordance with one or more implementations of the subject technology. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     The full-duplex communication system  510  includes a transmitter  512  (TX), a receiver  514  (RX), and a coupler  516 . In some implementations, the full-duplex communication system  510  is, or includes a portion of, the communication device  310  as depicted in  FIG. 3B . In some aspects, the full-duplex communication system  510  includes an F-connector  518 . Note that any other type of connector may be used in various applications. In some aspects, the receiver  514  may process, demodulate, decode, and/or interpret signals received via the F-connector  518  and the coupler  516 . 
     The coupler  516  services both upstream and downstream communications to and from the fiber node  135 A. The receiver  514  receives and samples signals from the coupler  516  and may provide them to a processor (e.g.,  330 ) for downstream processing. The processor  330  may generate digital signals for upstream transmission, and the transmitter  512  may generate amplified analog or continuous-time signals there from. The transmitter  512  may be implemented as a power amplifier to amplify the analog or continuous-time signals. The coupler  516  may be a bi-directional coupler that allows duplex transmission over the communication medium to and from the fiber node  135 A. The coupler  516  facilitates duplex transmission of the digital signals within the full-duplex frequency range (e.g., between 5-30 MHz). 
       FIG. 6A  illustrates an example of a continuous multicarrier spectrum  600  based on a combination of full-duplex and frequency division duplex communication systems in accordance with one or more implementations of the subject technology. The full-duplex and frequency division duplex communication systems use frequency bands of approximately 5-85 MHz (depicted as FDD RX  610 ), 108-684 MHz (depicted as FDX TX/RX  620 ), and 720-1218 MHz (depicted as FDD TX  630 ) for downstream FDD, full-duplex, and upstream FDD signals, respectively. 
       FIG. 6B  illustrates an example combined architecture of full-duplex and frequency division duplex communication system  650  in accordance with one or more implementations of the subject technology. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     The full-duplex and frequency division duplex communication system  650  includes transmitters  652 - 1  and  652 - 2 , receivers  654 - 1  and  654 - 2 , a coupler  658  and a triplexer  656 . In some implementations, the full-duplex and frequency division duplex communication system  650  is, or includes a portion of, the communication device  310  as depicted in  FIG. 3B . The transmitter  652 - 1  services upstream FDD transmissions and is coupled directly to an input of the triplexer  656 . The transmitter  652 - 2  services upstream FDX transmissions and is coupled directly to an input of the coupler  658 . The receiver  654 - 1  services downstream FDD transmissions and is coupled directly to an output of the triplexer  656 . The receiver  654 - 2  services downstream FDX transmissions and is coupled directly to an output of the coupler  658 . The coupler  656  may be a bi-directional coupler that allows duplex transmission over the communication medium to and from the fiber node  135 A. The coupler  658  is coupled directly to a bidirectional port of the triplexer  656  to facilitate the full-duplex transmissions to and from the receiver  654 - 2  and transmitter  652 - 2 , respectively. In some aspects, the full-duplex and frequency division duplex communication system  650  includes an F-connector  660 . Note that any other type of connector may be used in various applications. In some aspects, the receivers  654 - 1  and  654 - 2  may process, demodulate, decode, and/or interpret signals received via the F-connector  658  and the triplexer  656 . 
     The triplexer  656  services both upstream and downstream communications to and from the fiber node  135 A. The receivers  654 - 1  and  654 - 2  receive and sample signals from the triplexer  656  and may respectively provide them to a processor (e.g.,  330 ) for downstream processing. The received signals for downstream FDD processing may be filtered by the triplexer  656  to provide received signals within the downstream FDD frequency range (e.g., between 5-85 MHz) and passed on to the receiver  654 - 1 . The received signals for downstream FDX processing may be filtered by the triplexer  656  to provide received signals within the downstream FDX frequency range (e.g., between 108-684 MHz) and passed on to the receiver  654 - 2 . The processor  330  may generate digital signals for upstream transmission, and the transmitters  652 - 1  and  652 - 2  may generate amplified analog or continuous-time signals there from. The digital signals sent from the transmitter  652 - 1  for upstream FDD transmission may be filtered by the triplexer  656  to provide digital signals within the upstream FDD frequency range (e.g., between 720-1218 MHz) to the fiber node  135 A. The digital signals sent from the transmitter  652 - 2  for upstream FDX transmission may be filtered by the triplexer  656  to provide digital signals within the upstream FDX frequency range (e.g., between 108-684 MHz) to the fiber node  135 A. Each of the transmitters  652 - 1  and  652 - 2  may be implemented as a power amplifier to amplify the analog or continuous-time signals. 
     In a system, such as DOCSIS 3.1, where full-duplex and frequency division duplex are combined, any components, such as a frequency-domain multiplexing filtering device in the FDD system, can cause transmitter signal reflection (such as an echo) that severely limits the SNR that can be achieved in the FDX system. The dynamic range requirement of the downstream FDX transmission is dominated by the reflected transmission power (or transmitter echo) from the contiguous triplexer  656 . In some aspects, the triplexer  656  has a reflection coefficient of about −10 dB. In this respect, the transmitter echo may not be filtered out in the receiver  654 - 1  (FDX RX) and the transmitter echo can limit the dynamic range of the full-duplex and frequency division duplex communication system  650 . The input return loss looking into the F-connector  660  is determined by the triplexer  656 , which adds complexity in the triplexer  656  design, thus resulting in lower yield. 
     The full-duplex and frequency division duplex communication system  650  utilizes two sets of power amplifiers, namely transmitters  652 - 1  and  652 - 2 , where one power amplifier is configured for the upstream FDX transmission and one power amplifier is configured for the upstream FDD transmission. The two power amplifiers, however, add cost and complexity for digital domain stitching. 
     FIB.  6 C illustrates an example combined architecture of full-duplex and frequency division duplex communication system  670  in accordance with one or more implementations of the subject technology. Not all of the depicted components may be required, however, and one or more implementations may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, or fewer components may be provided. 
     The full-duplex and frequency division duplex communication system  670  includes a transmitter  672 , receivers  674 - 1  and  674 - 2 , a triplexer  676  and a coupler  678 . In some implementations, the full-duplex and frequency division duplex communication system  670  is, or includes a portion of, the communication device  310  as depicted in  FIG. 3B . The transmitter  672  services both upstream FDD and upstream FDX transmissions and is coupled directly to an input of the coupler  678 . In some implementations, the input of the transmitter  672  is coupled to a signal combiner (not shown) that combines the FDD and FDX signals to one pad. In this respect, the transmitter  672  may require additional power for driving the upstream signal compared to the transmitters  652 - 1  and  652 - 2  of  FIG. 6B . The receiver  674 - 1  services downstream FDD transmissions and is coupled directly to a first output of the triplexer  676 . The receiver  674 - 2  services downstream FDX transmissions and is coupled directly to a second output of the triplexer  676 . The coupler  678  is coupled directly to the transmitter  672  and to an input of the triplexer  676  to facilitate the full-duplex transmissions to and from the triplexer  676  and transmitter  672 , respectively. In some aspects, the full-duplex and frequency division duplex communication system  670  includes an F-connector  682 . Note that any other type of connector may be used in various applications. In some aspects, the receivers  674 - 1  and  674 - 2  may process, demodulate, decode, and/or interpret signals received via the F-connector  682  and the triplexer  676 . 
     The triplexer  676  services both upstream and downstream communications to and from the fiber node  135 A. The receivers  674 - 1  and  674 - 2  receive and sample signals from the triplexer  676  and may respectively provide them to a processor (e.g.,  330 ) for downstream processing. The received signals for downstream FDD processing may be filtered by the triplexer  676  to provide received signals within the downstream FDD frequency range (e.g., between 5-85 MHz) and passed on to the receiver  674 - 1 . The received signals for downstream FDX processing may be filtered by the triplexer  676  to provide received signals within the downstream FDX frequency range (e.g., between 108-684 MHz) and passed on to the receiver  674 - 2 . The processor  330  may generate digital signals for upstream transmission, and the transmitter  672  may generate amplified analog or continuous-time signals there from. The digital signals sent from the transmitter  672  for upstream FDD transmission may be filtered by the triplexer  676  to provide digital signals within the upstream FDD frequency range (e.g., between 720-1218 MHz) to the fiber node  135 A. The digital signals sent from the transmitter  672  for upstream FDX transmission may be filtered by the triplexer  676  to pass digital signals within the upstream FDX frequency range (e.g., between 108-684 MHz) to the fiber node  135 A. The transmitter may be implemented as a power amplifier to amplify the analog or continuous-time signals. In some implementations, the full-duplex and frequency division duplex communication system  670  in conjunction with the triplexer  676  can be implemented to support a time-division multiplex scheme. 
     In some implementations, the triplexer  676  may include a multiplexer using bandpass filters combined at a common input. For example, a first bandpass filter may be implemented as a low-pass filter to pass digital signals in the downstream FDD frequency range (e.g., between 5-85 MHz), a second bandpass filter may be implemented to pass digital signals in the FDX frequency range (e.g., between 108-684 MHz), and a third bandpass filter may be implemented as a high-pass filter to pass digital signals in the upstream FDD frequency range (e.g., between 720-1218 MHz). In other implementations, the triplexer  676  may be implemented as a filtering device that includes a diplexer and an additional filtering device coupled to the diplexer to pass digital signals in the three different frequency ranges discussed above. 
     As depicted in  FIG. 6C , any components that cause reflection of power are not placed before the coupler  678  (e.g., between the coupler  678  and the F-connector  682 ) to prevent leakage of the reflected transmission power to the FDX receiver (e.g.,  674 - 2 ). In some implementations, the full-duplex and frequency division duplex communication system  670  includes a termination resistor  680  for input matching. The termination resistor  680  is coupled directly to the triplexer  676 . By adding additional termination in the filter (e.g., the triplexer  676 ), the input reflection of the full-duplex and frequency division duplex communication system  670  can be optimized across a broad bandwidth. For example, although the triplexer  676  is not utilized to drive signals in the upstream FDD frequency range (e.g., between 720-1218 MHz), the termination resistor  680  is utilized to match the input reflection corresponding to the FDD frequency range and to reduce leakage of reflected transmission power in this frequency range. 
     The TX to RX leakage path (e.g., from the transmitter  672  to the receiver  674 - 2  via the triplexer  676 ) is through the coupler  678 . Isolation of the coupler  678  can be significantly low (&lt;−40 dB) for isolation within the FDX frequency band of 100-684 MHz. In this respect, the dynamic range requirement of the downstream FDX transmission can be relaxed by about ˜30 dB compared to the architecture of the full-duplex and frequency division duplex communication system  650 . Additionally, the design complexity of the triplexer  676  can be relaxed as well, which can lower the cost and increase the yield of production. This is because its reflection to the F-connector  682  is shielded by the loss of the coupler  678 . As depicted in  FIG. 6C , the full-duplex and frequency division duplex communication system  670  utilizes a single power amplifier (e.g.,  672 ), which simplifies the system design and reduces cost. 
       FIG. 7  conceptually illustrates an electronic system  700  with which one or more implementations of the subject technology may be implemented. The electronic system  700 , for example, can be a desktop computer, a laptop computer, a tablet computer, a server, a switch, a router, a base station, a receiver, a phone, a personal digital assistant (PDA), or generally any electronic device that transmits signals over a network. The electronic system  700  may be, and/or may include one or more components of, one or more of the media converters  135 A-C, one or more of the gateway devices  225 A-I, one or more of the electronic devices  222 A-I,  226 A-I,  228 A-I. Such an electronic system  700  includes various types of computer readable media and interfaces for various other types of computer readable media. The electronic system  700  includes a bus  708 , one or more processing unit(s)  712 , a system memory  704 , a read-only memory (ROM)  710 , a permanent storage device  702 , an input device interface  714 , an output device interface  706 , one or more network interfaces  716 , such as local area network (LAN) interfaces and/or wide area network interfaces (WAN), or subsets and variations thereof. 
     The bus  708  collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the electronic system  700 . In one or more implementations, the bus  708  communicatively connects the one or more processing unit(s)  712  with the ROM  710 , the system memory  704 , and the permanent storage device  702 . From these various memory units, the one or more processing unit(s)  712  retrieves instructions to execute and data to process in order to execute the processes of the subject disclosure. The one or more processing unit(s)  712  can be a single processor or a multi-core processor in different implementations. 
     The ROM  710  stores static data and instructions that are needed by the one or more processing unit(s)  712  and other modules of the electronic system  700 . The permanent storage device  702 , on the other hand, may be a read-and-write memory device. The permanent storage device  702  may be a non-volatile memory unit that stores instructions and data even when the electronic system  700  is off. In one or more implementations, a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) may be used as the permanent storage device  702 . 
     In one or more implementations, a removable storage device (such as a floppy disk, flash drive, and its corresponding disk drive) may be used as the permanent storage device  702 . Like the permanent storage device  702 , the system memory  704  may be a read-and-write memory device. However, unlike the permanent storage device  702 , the system memory  704  may be a volatile read-and-write memory, such as random access memory. The system memory  704  may store any of the instructions and data that one or more processing unit(s)  712  may need at runtime. In one or more implementations, the processes of the subject disclosure are stored in the system memory  704 , the permanent storage device  702 , and/or the ROM  710 . From these various memory units, the one or more processing unit(s)  712  retrieves instructions to execute and data to process in order to execute the processes of one or more implementations. 
     The bus  708  also connects to the input and output device interfaces  714  and  706 . The input device interface  714  enables a user to communicate information and select commands to the electronic system  700 . Input devices that may be used with the input device interface  714  may include, for example, alphanumeric keyboards and pointing devices (also called “cursor control devices”). The output device interface  706  may enable, for example, the display of images generated by electronic system  700 . Output devices that may be used with the output device interface  706  may include, for example, printers and display devices, such as a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, a flexible display, a flat panel display, a solid state display, a projector, or any other device for outputting information. One or more implementations may include devices that function as both input and output devices, such as a touchscreen. In these implementations, feedback provided to the user can be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. 
     Finally, as shown in  FIG. 7 , the bus  708  also couples the electronic system  700  to a network (not shown) through one or more network interfaces  716 , such as one or more LAN interfaces and/or WAN interfaces. In this manner, the electronic system  700  can be a part of a network of computers, such as a LAN, a WAN, an Intranet, or a network of networks, such as the Internet. Any or all components of the electronic system  700  can be used in conjunction with the subject disclosure. 
     Implementations within the scope of the present disclosure can be partially or entirely realized using a tangible computer-readable storage medium (or multiple tangible computer-readable storage media of one or more types) encoding one or more instructions. The tangible computer-readable storage medium also can be non-transitory in nature. 
     The computer-readable storage medium can be any storage medium that can be read, written, or otherwise accessed by a general purpose or special purpose computing device, including any processing electronics and/or processing circuitry capable of executing instructions. For example, without limitation, the computer-readable medium can include any volatile semiconductor memory, such as RAM, DRAM, SRAM, T-RAM, Z-RAM, and TTRAM. The computer-readable medium also can include any non-volatile semiconductor memory, such as ROM, PROM, EPROM, EEPROM, NVRAM, flash, nvSRAM, FeRAM, FeTRAM, MRAM, PRAM, CBRAM, SONOS, RRAM, NRAM, racetrack memory, FJG, and Millipede memory. 
     Further, the computer-readable storage medium can include any non-semiconductor memory, such as optical disk storage, magnetic disk storage, magnetic tape, other magnetic storage devices, or any other medium capable of storing one or more instructions. In some implementations, the tangible computer-readable storage medium can be directly coupled to a computing device, while in other implementations, the tangible computer-readable storage medium can be indirectly coupled to a computing device, e.g., via one or more wired connections, one or more wireless connections, or any combination thereof. 
     Instructions can be directly executable or can be used to develop executable instructions. For example, instructions can be realized as executable or non-executable machine code or as instructions in a high-level language that can be compiled to produce executable or non-executable machine code. Further, instructions also can be realized as or can include data. Computer-executable instructions also can be organized in any format, including routines, subroutines, programs, data structures, objects, modules, applications, applets, functions, etc. As recognized by those of skill in the art, details including, but not limited to, the number, structure, sequence, and organization of instructions can vary significantly without varying the underlying logic, function, processing, and output. 
     While the above discussion primarily refers to microprocessor or multi-core processors that execute software, one or more implementations are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In one or more implementations, such integrated circuits execute instructions that are stored on the circuit itself. 
     Those of skill in the art would appreciate that the various illustrative blocks, modules, elements, components, methods, and algorithms described herein may be implemented as electronic hardware, computer software, or combinations of both. To illustrate this interchangeability of hardware and software, various illustrative blocks, modules, elements, components, methods, and algorithms have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application. Various components and blocks may be arranged differently (e.g., arranged in a different order, or partitioned in a different way) all without departing from the scope of the subject technology. 
     It is understood that any specific order or hierarchy of blocks in the processes disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes may be rearranged, or that all illustrated blocks be performed. Any of the blocks may be performed simultaneously. In one or more implementations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     As used in this specification and any claims of this application, the terms “base station”, “receiver”, “computer”, “server”, “processor”, and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For the purposes of the specification, the terms “display” or “displaying” means displaying on an electronic device. 
     As used herein, the phrase “at least one of” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” does not require selection of at least one of each item listed; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. 
     The predicate words “configured to”, “operable to”, and “programmed to” do not imply any particular tangible or intangible modification of a subject, but, rather, are intended to be used interchangeably. In one or more implementations, a processor configured to monitor and control an operation or a component may also mean the processor being programmed to monitor and control the operation or the processor being operable to monitor and control the operation. Likewise, a processor configured to execute code can be construed as a processor programmed to execute code or operable to execute code. 
     A phrase such as “an aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples of the disclosure. A phrase such as an “aspect” may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples of the disclosure. A phrase such an “embodiment” may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples of the disclosure. A phrase such as a “configuration” may refer to one or more configurations and vice versa. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” or as an “example” is not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. 
     All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” 
     The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the subject disclosure.