# Presentation: 672338

## Powerline CommunicationsChallenges, Solutions, and Opportunities

***Presented by:***
**Jim McClanahan**
**of Nortel Networks**
- jimmcc1@nortelnetworks.com
- 770-708-4763

## Technical Challenges To Powerline CommunicationsOutline

**Introduction**
**The Power Budget**
**Emissions and Ingress**
**The Distribution System**
**End-User Issues**
**Conclusions**

## Technical Challenges To Powerline CommunicationsIntroduction

**There are several technical challenges to reliable, economical powerline communications.**
**In most cases, there are multiple approaches to solving each problem.**
**The solutions that are mentioned are not necessarily:**
**the only solutions,**
**the best solutions, or**
**the solutions being pursued by Nortel/NOR.WEB.**
**In fact, the problems mentioned may not be the only problems...**

- If it was easy, everyone would already be doing it...

## Technical Challenges To Powerline CommunicationsChallenge - The Power Budget

**The diagram above is a simplified view of the Power Budget.**
**The source and destination can be two powerline modems.**
**The path over the power network may not be a clean, direct path.**

## Technical Challenges To Powerline CommunicationsChallenge - The Power Budget

**The maximum power that the “transmitter” can inject is limited by Part 15.**
**The loss per unit of distance (the path loss) varies with the type of power infrastructure. In the “real-world”, little can be done to improve this.**
**The sensitivity of the receiver is typically limited by the noise floor found on the power infrastructure.**

_**What drives the Power Budget?**_

- The Power Budget determines “how far” you can communicate.

## Technical Challenges To Powerline CommunicationsSolutions - The Power Budget

**May focus on “small footprint” applications such as in-home LANs.**
**Different modulation schemes and signal bandwidth could be considered.**
**Some type of regeneration or amplification might be used.**
**Could seek changes to the emissions limits of FCC Part 15.**

## Technical Challenges To Powerline CommunicationsChallenge - Emissions and Ingress

***On the one hand...***
**FCC Part 15 sets limits on Emissions.**
**Even if these limits are met, a device still may not cause harmful interference.**
***But on the other hand...***
**An unlicensed device must accept any interference it receives.**

- The worse of both worlds...

## Technical Challenges To Powerline CommunicationsChallenge - Emissions and Ingress

- Fluorescent Lights
*(after 20 minute warm up)*

- Digital PowerLine

- Signals like ours are little RF fish in a big RF pond...

## Technical Challenges To Powerline CommunicationsSolutions - Emissions and Ingress

**Different modulation schemes have different spectral characteristics. FSK tends to concentrate power around the carrier. Spread spectrum **
**Make certain the signal gets on the power system--coupling mismatches will likely be the single “strongest” source of emissions.**
**Filters and other ancillary items might reduce emissions.**

- From an RF perspective, it’s a dirty world out there...

## Technical Challenges To Powerline CommunicationsChallenge - The Distribution System

**In North America, the low-voltage (secondary distribution) system covers a limited area. This may mean that wide deployment will require connection to the high-voltage (primary distribution) system.**
**Capacitors are used for VAR compensation on the distribution network. These are typically connected phase-to-neutral and offer an alternate path to ground for signals on the powerline.**
**During normal operation and maintenance, switching takes place which alters the topology of the distribution network.**

## Technical Challenges To Powerline CommunicationsSolutions - The Distribution System

**Power and telecommunications tend to be different worlds. It takes creativity and teamwork to turn these differences into synergies instead of obstacles.**
**The power system is the way it is for a number of reasons based on over a century of experience--get over it********...**
**Understand the reality...**
- spend time in the field
- talk to people
- look at the system diagrams
- measure things
- study operations and maintenance records

## Technical Challenges To Powerline CommunicationsChallenge - End-User Issues

**How do you interface at the customer end?**
- plug-in card
- serial
- Ethernet
- USB
**What types of drivers are required and how are they installed?**
**Is it easy to use with web browsers, e-mail, etc.?**

## Technical Challenges To Powerline CommunicationsSolutions - End-User Issues

**Listen to customers.**
**Look at the market.**
**Balance multiple objectives:**
- ease of installation
- ease of use
- installed cost
- flexibility
- technical elegance
- technology evolution/avoiding obsolescence

## Technical Challenges To Powerline CommunicationsConclusions

**There are lots of challenges, but...**
- customers want choices,
- utilities want to diversify their business,
- regulators want to encourage competition, and
- telcom service providers want new ways to the customer.
**The solution of some technical problems may require the assistance of regulators.**

- Success comes to those who know it isn’t coming to them and go out and get it.
- -Frank Tyger