Reliable, low cost Power Line Communication (â€œPLCâ€) technology enables ubiquitous home automation and device command and control. PLC utilizes infrastructure present in every home, eliminating the unnecessary expense and inconvenience of new wires or antenna-based networks. This article describes the characteristics of the power line medium, various PLC technologies used for control applications, and ITRAN Communications’ unique, proprietary solutions to the problems of power line command and control networking. Further, the integration of ITRAN’s robust IT800â„¢ PLC modem technology with Microsoft SCPâ„¢ (Simple Control Protocol) in a single System-on-Chip seamlessly extends the benefits of UPnP (Universal Plug and Play) control schema to devices with limited memory and processing power and to networks with limited bandwidth, simultaneously creating a uniform platform for simple, straightforward development of a wide variety of in-home PLC based control applications.
The Power Line Medium
While many have attempted to use the power line as a control medium, it has not lived up to expectations, earning a reputation for questionable reliability. The fact is that the residential power line is an extremely difficult and noisy communications medium, characterized by several unpredictable and strong forms of interference. Every appliance that is connected to an electrical outlet contributes interference, which can be approximated as Additive White Gaussian Noise (AWGN). Dimmer switches, motorized electrical appliances and computers also introduce pulse interference, making it an especially perilous environment for non-robust communications. Power line communication channels are also characterized by fast fading, non-flat frequency responses, carrier wave signal interference and unpredictable jamming, every one of which corrupt power line communication. All the forgoing make it exceedingly difficult to ensure reliable power line communication and help explain the difficulties that power line communication technologies have had in delivering reliable communication. ITRAN’s patented and patent pending solutions to the problems of power line communication overcome the interference and reliability problems that characterize the power line and that have plagued alternative technology solutions, offering demonstrably superior performance over this harsh medium.
PLC Technologies for Home Automation and Control
Traditional PLC control solutions, such as X-10 (60bit/sec), illustrate the long-standing demand for simple device control over power line. Unfortunately, these solutions have been limited by their data rate, reliability and scalability. Such control solutions may be acceptable for “On, Off and Dim” functionality but they send â€œunacknowledgedâ€ communication packets, failing easily in high-interference environments. Notwithstanding the technological limitations of X-10, it has a significant and longstanding installed base. For this reason it is critical that other power line communications solutions co-exist with X-10 signaling schema. ITRAN’s IT800 power line transceiver co-exists with X-10 products.
The CEBus Standard (EIA-600) is a protocol specification developed by the Electronic Industries Association (EIA) to support communication between residential consumer products. Traditional CEBus devices suffer from limited bit rate and cross-phase communications difficulties. Existing CEBus PLC chips (6.6kbps), although providing improvements over their X-10 predecessors, are not reliable enough for many of today’s demanding PLC applications. ITRAN’s patented technology significantly surpasses the performance of CEBus compatible modems at the same or lower total solution cost. ITRAN’s IT800 power line transceiver also co-exists with CEBus products.
ITRAN IT800 Power Line Transceiver
The IT800 is a highly reliable integrated power line transceiver possessing extremely high in-phase and cross-phase reliability. The implementation of an advanced patented modulation technique, Differential Code Shift Keying (DCSK), enables extremely robust communication at data rates up to 7.5Kbps. In addition to the inherent interference immunity of the patented DCSK modulation, the IT800 utilizes several mechanisms for enhanced communication robustness, such as forward, short block, soft decoding error correction (patent pending) and special synchronization algorithms. A USART/SPI host interface enables simple seamless connection to an external host for a low cost robust total solution. The IT800 complies with worldwide regulations (such as FCC part 15, CENELEC bands A & B and Far East regulations) and is an ideal solution for a variety of home automation and control applications.
IT800/SCPâ„¢ Unified PLC Platform
The collaboration of Microsoft and ITRAN Communications lead to the co-development of a unified PLC platform for home automation and device control. The IT800/SCP platform combines, in a single chip, Microsoft’s Simple Control Protocol (SCP) and ITRAN’s robust IT800 command/control power line carrier modem. SCP seamlessly extends the benefits of UPnP device control to devices with limited memory and processing power and to networks with limited bandwidth. The IT800/SCP Chip Set provides an efficient, inexpensive, no-new-wires means to network lightweight devices. Controllable by device application microprocessors as inexpensive as low-end eight-bit PICs, the IT800/SCP ASIC design is optimized for use with simple devices such as light switches, alarm clocks and appliances. Not only can the IT800/SCP chip be part of a peer-to-peer network of other SCP-enabled devices but also, via Microsoft’s SCP-to-UPnP Bridge, it can link seamlessly with Universal Plug and Play (UPnP) networks. Via the SCP-to-UPnP Bridge, SCP devices automatically appear as native UPnP devices on an IP network. The SCP devices can then be controlled using standard UPnP tools. SCP supports all standard UPnP capabilities as well as peer-to-peer eventing. A device can subscribe to a particular property on another device and receive notifications whenever the value of the subscribed property changes. These property relationships are stored within each device, allowing full and automatic recovery following a power outage.
Microsoft Simple Control Protocol (SCP) ITRAN IT800 Power line Carrier Modem
Simple, efficient device control implementationn
Optimized for lightweight devices and low-speed control networks
Full UPnP interoperation through automatic bridge
Automatic device discovery
Simple messaging semantics
Reliable broadcast and point-to-point communications
Selectable security levels
Multiple logical networks
C source library implements SPI ASIC interface
Ideal for command and control, lighting, home automation, security, energy management, and automated meter reading applications
Extremely high in-phase and cross-phase reliability
FCC Part 15 compliant
Configurable to transmit in European CENELEC A & B bands
7.5 Kbps maximum throughput (approx. 4 Kbps with full Forward Error Correction) (2.5/1.75 Kbps in CENELEC mode)
USART/SPI simple host interface
Adaptive Rate Control
Co-exists with CEBus and X10 products
Reliable, robust, low-cost technology for power line based home automation and device control is available today in ITRAN Communications’ DCSK based IT800 modem. The integration of the IT800 with Microsoft Simple Control Protocol enables the development of a wide variety of in-home PLC based applications with significantly superior performance than existing PLC command and control solutions. IT800 â€œSCP Readyâ€ evaluation and development kits are available from ITRAN.
For additional information or to purchase IT800 â€œSCP Readyâ€ evaluation kits, please visit ITRAN’s web site or contact us at:
ITRAN Communications, Inc.
5150 North Tamiami Trail Naples, FL 34103
Tel: +1-941-430-1409 Fax: +1-941-430-1509
Email: ITRANusa@ITRANcomm.com Web Site: www.ITRANcomm.com
Oren Kaufman, IT800 Project Manager, joined ITRAN in 1997. Mr. Kaufman is a communications and VLSI expert and is responsible for the research and development of home automation and control solutions in ITRAN. Kaufman’s background is in communications, information theory and stochastic processes and he holds M.Sc.EE and MBA degrees from Ben-Gurion University in Israel.
Asaf Avidan manages ITRAN’s customer support activity. Mr. Avidan possesses over 15 years of experience in R&D, marketing and customer support management. Prior to joining ITRAN, Mr. Avidan established and managed the customer support department of Texas Instruments Short Distance Wireless business unit. He holds a B.Sc EE (with honors) and LL.B degrees from Tel-Aviv University, Israel.