A wireless connection for home digital devices, between the Internet, a laptop and a printer for example, seems like a good idea-buy a Wi-Fi router and you're in business-no painful running of wires from room to room, and it works pretty well. But think about it, do a little research, and you might think twice.
What Would We Like to Connect?
For now, wireless connection between the Internet, a laptop, and a printer seems like enough (and plenty of users even complain about their problems keeping that much working). But think about it -- in homes, changing the wired infrastructure is a significant job so if you're rewiring or building a new home, you want to plan for future growth. We're on the cusp of a connectivity revolution; so far, there may not be many homes with a significant amount of convergence between systems, but increased interconnections are inevitable. Home automation is coming and a growing number of automation products are being designed to communicate via the Internet. This growth will happen through both push and pull. Major manufacturers are betting on it by bringing new products onto the market that are designed to be controlled by local area networks (LANs) and to interact by way of the Internet. The more word gets out about the added convenience, savings in energy costs and enhancements in safety and security, the more people are going to want systems that offer these benefits.
Number one on the list is HDTV. Go into any electronics or appliance store and you'll find a wall of HDTVs. The latest and greatest in that market, and it's just beginning, are IPTVs-web-enabled television that can directly access the Internet; but even better are network-enabled TVs that can access the Internet through your home network with a built-in RJ45 wired Ethernet connection. Just think how great it will be to sit back in your easy chair and watch TV and surf the Web on your big-screen TV, using your hand-held remote controller. You'll also be able to download streaming video without having to go through a cable company. You can directly connect to popular websites like YouTube, Pandora, Netflix and Amazon VOD. With a networked TV you'll be able to view the files in your laptop or PC and also be able to access other home equipment like DVRs, Blu-ray players, and games.
Another important component of home media systems, is audio. There are a number of systems that allow you to use different audio sources and different speakers in multiple rooms; and to select which player to connect to which speakers, using a control pad or wireless remote. Just think, you can have your MP3 player piped into your home office while your spouse can be listening to FM or satellite radio in another room and each of your kids can connect to their music and have it follow them throughout the house. Sources and players can be interchanged in every room. This is achieved by connecting the components to your LAN.
Economizing on Energy Costs
Media may be the sexy item that first catches homeowners' attention, but once they come to accept the idea of interconnecting devices throughout the home, they might be easily convinced that a home network could also be a simple way to save money on their energy costs. The largest contributors to residential electric bills are heating, ventilating and air conditioning (HVAC) and lighting. In most homes, controlling lighting means an on/off switch and possibly a dimmer. But there are available systems that can be networked to coordinate lighting throughout the home. One approach is to provide a list of standard "scenes" such as: company's coming; everyone's gone out to work and school; someone's just come home; everyone's in bed; the family is away on vacation. Of course local controls in every room can override the scenes. You can even have a remote control in your car to turn on the lights when you're in the driveway. Occupancy sensors can be used to control lighting according to whether or not someone is in a room. Lighting control systems can be integrated with motorized window coverings so that according to the time of day, room lights can be dimmed and window shades opened. Then temperature control can be added to the network mix. HVAC can be coordinated with window shade controls, to let in less sunlight during summer months and more during the winter. The scene approach can also be used with temperature control, for example reducing artificial heating or cooling when the home is unoccupied and then preparing in advance for the homecoming. Calendar and time-based controls can be overridden from just about anywhere because the home network can be accessed via an Internet browser.
Homeowners can minimize their energy costs by maximizing their control over heating, cooling and lighting, all integrated into a single system. There is no doubt that as more systems evolve to implement these functions, more people will want to have this added value. Think of it, video and audio media plus lighting and temperature all controlled over a single network. But there's still more.
Safety and Security
Home security systems, which include intrusion alarms, electrically operated door locks, surveillance cameras and intercoms are all available with networking connections. It's conceivable for example that you expect Aunt Minnie to arrive from out of town while you're at work. Instead of leaving a key under the doormat, she can phone you that she's at your front door. From your desktop computer or even your smart phone, you can bring up an image from the outdoor-rated IP surveillance camera that views your door. After seeing that it's really Minnie, you can unlock the door, disarm the alarm system, turn on the lights and adjust the temperature.
The fire alarm system can not only wake you in the middle of the night with an alarm horn, it can automatically report the fire to a central station, and since it can be networked with the lighting system, it can cause the lights outside of your home to flash on and off so that the emergency responders will be able to locate you more quickly. What's more, it can automatically turn on all of the lights in the house, but not at full brightness so you won't be blinded by the smoke; it can open motorized blinds and unlock the garage door for quicker escape and announce where in the house the fire is located. And if you're not home, it can send you a text message.
One of the problems faced by electric utilities is that although peak loading may be much higher than the average load, they have to be able to handle the highest peaks. These may only occur for a part of the day and will vary according to the season of the year. In order to improve this situation, some utilities charge lower rates during off-peak hours.
The smart grid is the name given to the system that adds two-way digital communication to the power delivery system. The interface between the electric utility and the home consumer is a smart meter. These meters allow the utility to charge different rates throughout the course of a day and pass the information along to the consumer, who can make decisions about when to use high-load equipment such as washers and driers, water heaters and dishwashers. Taking advantage of the variable rates can now even be done automatically. You can buy major appliances with built-in network connections that make it possible for the utility to program them to turn on during lower cost periods. This is a win-win situation-it allows utilities to operate more predictably, with fewer chances of blackouts and it allows homeowners to reduce the cost of their electricity.
One of our most pressing social problems is the high cost of health care, which is sure to get even higher as the population peak known as the baby boom, advances into old age. The first crop of babies born after World War II is reaching the age of 65 this year (2011). According to the U.S. Census, by 2030, 71 million Americans will be over age 65. A greater percentage of health dollars are spent on this age group than their proportion of the population would suggest. There is a growing consensus that health care costs can be significantly reduced through proactive rather than reactive care. If each patient has a digital electronic file containing base-level readings of their body functions, regular monitoring of these numbers can allow a medical professional to spot trends and intervene well before the person has gone into crisis mode. Furthermore, research indicates that people would prefer to be able to stay in their homes as long as possible rather than having to move to a health care facility. Aging people could stay at home with regular visits from an aide, while vital signs such as blood pressure, blood glucose, pulse rate, temperature and oxygen index can be regularly monitored with sensors, and the data transmitted over the Internet to the appropriate professionals. These factors are driving the growth of a field called telemedicine. The American Telemedicine Association is advocating for the acceptance of "telehealth services" by Medicare, with growing success.
Another benefit of telemedicine is that people who live in areas remote from healthcare centers will be able to communicate with primary care providers and specialists, by means of sensor data and video.
A couple of other applications include:
- Measuring the health of your home by connecting humidity, air quality and temperature sensors to your HVAC system.
- Online learning for K-12th graders on up to college level. There are currently over a million children enrolled in online learning projects. Twenty-seven states allow full-time online learning. Pennsylvania, for example treats online charters the same as brick and mortar charter schools, providing full-time tuition-free education. Some states have started using online classes rather than snow days in bad weather.
Wired vs. Wireless Home Networks
All of these applications, plus more that will be coming, require interconnection through a home-based local area network (LAN) and most of these will be enhanced by, or will even require, connection to the Internet. The control software is generally downloaded into a home computer, which can be programmed to oversee and report on all of the systems With each new function, the amount of information that will have to be transmitted between all of the various components and with the Internet, is growing at a tremendous rate. Each application has to transmit and receive data at their own minimum rate (throughput in megabits per second). As applications are added, the total required throughput grows. This translates to the need for large amounts of bandwidth.
Some applications, such as streaming video to a home or from a home to a medical facility, or from an IP security camera, require large amounts of especially stable throughput.
Within a home, the throughput of a typical wireless connection depends on a number of different factors. A standard for wireless LANs was first published in 1997 by the IEEE as 802.11. It only supported a maximum throughput of 2 Mbps so they published 802.11b in 1999 to extend the maximum throughput to 11 Mbps. Both of these were to be transmitted at an RF frequency of 2.4 GHz, which is part of the ISM (industrial, scientific and medical) band freed up by the FCC in 1985 for unregulated use. In 2003, the IEEE ratified 802.11g and in 2009, 802.11n, which were both intended to overcome earlier limitations and also transmit at 2.4 GHz. The maximum practical throughput for 802.11g is about 20 Mbps under ideal conditions. 802.11n transmits data by using four parallel streams, but even that has many limitations. Maximum practical throughput is about 50Mbps, and since the cost is 2 to 3 times that of 802.11g it is generally used only for commercial applications.
Category 6 unshielded twisted pair (UTP) copper cable is rated to have a minimum throughput of 1 Gbps. Properly installed, a LAN using UTP cable will be in a star configuration, which means that a separate cable will be run from a central closet to each connection point in the home. Every one of these cables will be able to transmit data at a rate of 1 Gbps, in contrast to wireless, in which a given space can only carry one signal at a given frequency.
Limitations of a Wireless LAN Connection
- Streaming video requires 20 to 100 Mbps for each television receiver, so at best, wireless can connect video from one source at a time, for example either Internet or Blu-ray, to one TV set.
- Because of its much lower throughput, a wireless LAN will be unable to handle much of the traffic that homeowners will be wanting within the next 5 to 10 years.
- If you have any near neighbors, especially in a multiple unit dwelling, it is very possible that you will interfere with each other.
- It is possible that a device like a microwave oven or a nearby medical diathermy machine, which use the same 2.4 GHz frequency as the wireless signal, will cause interference.
- The human body can introduce a scattering effect, which is a source of instability, most troublesome for telemedicine, but also very annoying for applications like video. HDTV requires bandwidth stability and guaranteed QoS (quality of service).
- Effective throughput will be reduced in the presence of electrical noise because some of the required bits will have to be used for error correction in the digital stream.
- As objects are moved in the room, the antenna may need to be repositioned.
- The Internet performs poorly over a wireless connection when there is electrical interference (noise), because TCP (transmission control protocol), which is the basis for Internet transmission, was designed for a wired connection, where information lost due to electrical noise is rare.
- It is easier for someone to tap into your network and steal private information.
- More power is required for transmitting and receiving wireless relative to wired.
- The greater the number of applications running on your wireless network, the more chance there is that they will interfere with each other.
- The more applications that are running on your wireless network, the more radio frequency radiation will exist in your home environment.
Summing It Up
The uses for a home digital network will be growing rapidly in the next 5 to 10 years. This will put a very heavy burden on the infrastructure for transmitting data throughout the home. Building that infrastructure with CAT 5e or CAT 6 wiring, "home run" from a central closet will allow for 1 Gbps to each connector-and in some rooms it might pay to have more than one run. That backbone will be enough to comfortably handle any applications that might come along in the next 10 years or more. A wireless network couldn't even come close.