By a News Reporter-Staff News Editor at Journal of Engineering -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Vijayasankar, Kumaran (Dallas, TX); Vedantham, Ramanuja (Allen, TX); Pande, Tarkesh (Dallas, TX), filed on March 3, 2015, was published online on April 19, 2016.
The assignee for this patent, patent number 9319238, is TEXAS INSTRUMENTS INCORPORATED (Dallas, TX).
Reporters obtained the following quote from the background information supplied by the inventors: "Power line communications (PLC) include systems for communicating data over the same medium that is also used to transmit electric power to residences, buildings, and other premises, such as wires, power lines, or other conductors. In its simplest terms, PLC modulates communication signals over existing power lines. This enables devices to be networked without introducing any new wires or cables. This capability is extremely attractive across a diverse range of applications that can leverage greater intelligence and efficiency through networking PLC applications include utility meters, home area networks, and appliance and lighting control.
"PLC is a generic term for any technology that uses power lines as a communications channel. Various PLC standardization efforts are currently in work around the world. The different standards focus on different performance factors and issues relating to particular applications and operating environments. One of the most well-known PLC standards is G3-PLC, which has been approved by the International Telecommunication Union (ITU).
"Using PLC to communicate with utility meters enables applications such as Automated Meter Reading (AMR) and Automated Meter Infrastructure (AMI) communications without the need to install additional wires. Consumers may also use PLC to connect home electric meters to an energy monitoring device or in-home display monitor their energy consumption and to leverage lower-cost electric pricing based on time-of-day demand.
"As the home area network expands to include controlling home appliances for more efficient consumption of energy, OEMs may use PLC to link these devices and the home network. PLC may also support home and industrial automation by integrating intelligence into a wide variety of lighting products to enable functionality such as remote control of lighting, automated activation and deactivation of lights, monitoring of usage to accurately calculate energy costs, and connectivity to the grid.
"The manner in which PLC systems are implemented depends upon local regulations, characteristics of local power grids, etc. The frequency band available for PLC users depends upon the location of the system. In Europe, PLC bands are defined by the CENELEC (European Committee for Electrotechnical Standardization). The CENELEC-A band (3 kHz-95 kHz) is exclusively for energy providers. The CENELEC-B, C, D bands are open for end user applications, which may include PLC users. Typically, PLC systems operate between 35-90 kHz in the CENELEC A band using 36 tones spaced 1.5675 kHz apart. In the United States, the FCC has conducted emissions requirements that start at 535 kHz and therefore the PLC systems have an FCC band defined from 154-487.5 kHz using 72 tones spaced at 4.6875 kHz apart. In other parts of the world different frequency bands are used, such as the Association of Radio Industries and Businesses (ARIB)-defined band in Japan, which operates at 10-450 kHz, and the Electric Power Research Institute (EPRI)-defined bands in China, which operates at 3-90 kHz.
"To process different priority levels, G3-PLC allows for the use of a High Priority Contention Window (HPCW) where only the nodes that have a high priority packet can contend and transmit the frame. However, when there are no nodes in the network that have a high priority frame, the other nodes still have to wait for the entire HPCW window before transmitting any frames. This is a waste of network resources. This delay for the HPCW window will affect the achievable throughput because a node with high priority frames may not occur for a significant amount of time in the network. Also, the existing G3-PLC mechanism only ensures collision avoidance with neighboring nodes that can sense the channel but not with hidden nodes."
In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "Embodiments of methods and systems for overlapping priority contention windows in G3-PLC networks are presented. In one embodiment, a Normal Priority Contention Window (NPCW) is allowed to overlap with the HPCW. The minimum contention window for the normal priority frames (i.e., NPCW) is equal to or longer than the contention window for high priority frames (i.e., HPCW). By making the NPCW longer than the HPCW, the high priority frames will have a better chance to get access to the channel.
"This overlap of HPCW and NPCW will have only a small impact on the performance of the high priority frames. The window size for collision of nodes that intend to transmit normal priority frames is increased (e.g., doubled if the HPCW and NPCW are initially the same length. However, the window size for high priority frames is kept equal to the original HPCW. During a retransmission attempt, the back-off period for normal priority frames will push the normal priority frames out of the HPCW, but high priority frames will continue to attempt transmission in the HPCW. Hence, the high priority frames get an increased chance for a successful transmission during a retransmission attempt.
"The proposed solution helps improve network throughput without significantly affecting the ability of the network to provide priority. Additionally, allowing overlapping NPCW and HPCW improves network throughput during periods when there are no high priority frames, which are significantly long periods in realistic traffic conditions."
For more information, see this patent: Vijayasankar, Kumaran; Vedantham, Ramanuja; Pande, Tarkesh. Overlapping Priority Contention Windows Power Line Communications Networks. U.S. Patent Number 9319238, filed March 3, 2015, and published online on April 19, 2016. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=9319238.PN.&OS=PN/9319238RS=PN/9319238
Keywords for this news article include: Energy, Electric Power, TEXAS INSTRUMENTS INCORPORATED.
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