PRIME (an acronym for "powerline intelligent metering evolution") is a

specification A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard. There are different types of technical or engineering specificat ...

for narrow band

powerline communication Power-line communication (also known as power-line carrier or PLC) carries data on a conductor that is also used simultaneously for AC electric power transmission or electric power distribution to consumers. A wide range of power-line communicat ...

published by the PRIME Alliance consortium. Powerline communication uses power lines as transmission media. PRIME was conceived in 2007.Berganza, Inigo, Alberto Sendin, and Javier Arriola
PRIME: Powerline intelligent metering evolution
CIRED Seminar. 2008. First publications date back to 2008. In 2009 multi-vendor interoperability was demonstrated and the PRIME Alliance launched. The PRIME Alliance has interoperability tests in place, which are carried out by multiple accredited test laboratories. Currently, the tests have been passed by over 40 products. The primary usage of PRIME is in

advanced metering infrastructure A smart meter is an electronic device that records information such as consumption of electric energy, voltage levels, current, and power factor. Smart meters communicate the information to the consumer for greater clarity of consumption be ...

. According to the PRIME Alliance, more than 5 million meters in 9 countries are deployed.Prime Alliance News Letter
December 2014.

Specification overview

The PRIME specificationNarrowband orthogonal frequency division multiplexing power line communication transceivers for PRIME networks
International Telecommunication Union. 2012. is structured into Physical Layer, MAC Layer and Convergence Layer. For operations and control, a "Management Plane is specified".

Physical layer

Distribution networks are usually made of a variety of conductor types, and terminating into loads of different impedances, which also vary over time. Such infrastructure results in a communication channel which has a time dependent amplitude and phase response that varies with frequency. Interference and impulsive noise produced by motors, switching power supplies and halogen lamps reduces the reliability of communication signals. Due to line attenuation, the noise is location dependent. The PRIME

physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer; The layer most closely associated with the physical connection between devices. This layer may be implemented by a PHY chip. Th ...

is based on

OFDM In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital comm ...

(Orthogonal Frequency Division Multiplexing) and Differential Phase Shift Keying (BPSK, DQPSK and D8PSK) as carrier modulation. To address averse power line channel properties, robustness mechanism convolutional encoding (optional),

scrambling Scrambling is a mountaineering term for ascending steep terrain using one's hands to assist in holds and balance.''New Oxford American Dictionary''. It is also used to describe terrain that falls between hiking and rock climbing (as a “scram ...

and

interleaving Interleaving may refer to: * Interleaving, a technique for making forward error correction more robust with respect to burst errors * An optical interleaver, a fiber-optic device to combine two sets of dense wavelength-division multiplexing (DWD ...

are used. PRIME Specification v1.4 also introduces repetition codingDraft Specification for PoweRline Intelligent Metering Evolution
PRIME Alliance TWG. Revision 1.4. 2014. as additional robustness mechanism. Originally, PRIME uses carrier frequencies (42 – 89 kHz) within the

CENELEC CENELEC (french: Comité Européen de Normalisation Électrotechnique; en, European Committee for Electrotechnical Standardization) is responsible for European standardization in the area of electrical engineering. Together with ETSI (telecom ...

A band and offers raw data rates between 5.4 kbit/s (Robust mode: DBPSK with convolutional encoding and repetition code) and 128.6 kbit/s (D8PSK). Since specification version 1.4, more frequency bands were introduced to utilize the higher frequencies (up to 471 kHz) in

ARIB The , commonly known as , is a standardization organization in Japan. ARIB is designated as the center of promotion of the efficient use of the radio spectrum and designated frequency change support agency. Its activities include those previously ...

and

FCC The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdictio ...

bands. Using the full FCC band, raw data rates are eight times as high as in CENELEC A band.

MAC layer

The MAC layer specifies the

data link layer The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer ...

of the

OSI model The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications ...

. In a PRIME subnetwork two device types exist: Base nodes and Service nodes. Base nodes manage subnetwork resources and connections. All devices, which are not Base nodes are Service nodes. Service nodes register with Base nodes to become part of a subnetwork. The topology generated by a PRIME subnetwork is a tree with the Base node as trunk. To extend the subnetwork range, a Base node can promote a Service node from terminal state to switch state. Switches relay data in the subnetwork and build the branch points of the tree. Powerline is a shared communication media. Base nodes and switches announce their presence with beacon messages in well specified intervals. These beacons provide a common time notion to a subnetwork. Time is split into shared contention period (SCP) and contention free period (CFP). During SCP, nodes can access the channel using

CSMA/CA Carrier-sense multiple access with collision avoidance (CSMA/CA) in computer networking, is a network multiple access method in which carrier sensing is used, but nodes attempt to avoid collisions by beginning transmission only after the channel ...

. For the CFP period, the base node arbitrates channel access. To reduce transmission overhead, PRIME uses dynamic addresses to address nodes in a subnetwork. The addressing scheme resembles the tree structure of the subnetwork and consists of local switch id, local node id and local connection id. Routes are established during service node registration. PRIME makes use of address structure for packet routing, which reduces state information needed by service nodes. Base node and service nodes monitor network attachment based on periodic exchanged control messages, so called "keep alive messages". PRIME allows connection oriented communication. The PRIME MAC layer includes control mechanism/messages to open and close unicast, multicast and broadcast connections. To provide reliable connections,

Selective Repeat ARQ Selective Repeat ARQ/Selective Reject ARQ is a specific instance of the automatic repeat request (ARQ) protocol used to manage sequence numbers and retransmissions in reliable communications. Summary Selective Repeat is part of the automatic ...

is used between the two connection end points. PRIME specifies a security profile for encryption of MAC layer packets. Encryption is based on AES-CCM with 128bit keys and key derivation mechanism recommended by NIST.

Convergence layer

The PRIME convergence layer is split into a Common Part Convergence Sublayer (CPCS) and Service Specific Convergence Sublayer (SSCS). The CPCS provides a

segmentation and reassembly Segmentation and reassembly (SAR) is the process used to fragment and reassemble variable length packets into fixed length cells so as to allow them to be transported across Asynchronous Transfer Mode Asynchronous Transfer Mode (ATM) ...

mechanism to all SSCS. PRIME currently specifies four SSCS: *

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version d ...

SSCS *

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. I ...

SSCS * NULL SSCS, a transparent SSCS for node management and custom use * IEC 61334-4-32 SSCS for use with DLMS/COSEM

Management plane

The PRIME Management Plane specifies interfaces for local and remote management of nodes and for firmware upgrade.

References

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External links

Prime Alliance Specification Downloads

ITU Recommendation G.9904
Electrical grid Smart grid Emerging technologies