Changing Spectrums of In-Home Wireless
by Cees Links
For many years tech-evangelists promised the arrival of the “smart home” – the automated home with devices that talk to each other, with appliances and central home systems controlled from a home dashboard or over the internet.
Except for a few hobbyists and early innovators, most homes today are still stupid.
Why aren’t our homes as smart as our cars?
Inside almost every home you will find some flavor of wireless used for connecting devices. Cordless phones use DECT and related technologies; CDMA and GSM for cell phones; and Wi-Fi for voice and high-speed data applications.
Infrared (IR) is another network in most homes – usually utilized to connect entertainment centers to portable remote controls. Used in about 98% of remote controls, IR has been around for decades. IR is cheap, works and is relatively reliable.
However, Infrared is now being phased out by RF-based technologies such as Wi-Fi, Bluetooth, RFID and ZigBee RF4CE. By using radio frequencies it is no longer necessary to aim and shoot a remote control device at the equipment it is controlling. Unlike IR, wireless radio transmits through walls and furniture. This enables homeowners to hide their “ugly” set-top boxes and controllers behind closed doors.
IR is also not very compatible with new screen technologies. A Plasma DTV inverter can interfere with IR signals. The backlighting on many LCDs can interfere with the TV’s IR receiver.
Besides, you need interactivity for a truly smart home, don’t you? By offering interactivity, additional capabilities can be offered. This includes interactive TV shopping as well as access to temperature and energy use monitoring throughout the home.
In addition, by using an interactive screen, the homeowner can monitor health status, lock and unlock doors and windows, and by using a security camera at the front door, see who is ringing their doorbell. Is it a delivery person, is it their mother in law, or is it an unwanted solicitor? A small captured image can be wirelessly sent from a small camera over the door to the display on the remote.
New low power LAN for the home
Unlike Local Area networks like Wi-Fi and DECT, and the cellular wireless networks which are targeted at big bandwidth, power hungry applications such as video, music, gaming and voice, ZigBee RF4CE is a Local Area Network (LAN) that is aimed at low power, battery operated applications such as home automation, environmental controls, security and health monitoring, etc.
The ZigBee RF4CE (IEEE 802.15.4) network is similar in range (150-250 feet) and topology to DECT and Wi-Fi. A typical system would consist of one base station with fixed and mobile applications throughout the home that would wirelessly talk to it, and an internet connection to the set top box.
In addition to RF4CE, there are some who are looking at Bluetooth as another possible replacement for IR. Bluetooth has been around for over ten years and is ideally suited for point-to-point links, which means that the devices can be used in pairs, such as a headset with a phone or a mouse with a PC. In theory, Bluetooth can link up to 7 devices, but the result is not very efficient since only two of those seven devices can communicate to each other at the same time.
The Peripheral Area Network
Unlike LAN technologies like RF4CE and Wi-Fi, Bluetooth is a PAN, a Peripheral Area Network. If you have a Bluetooth phone headset, and travel 15 ft. away from the phone, the quality of the connection starts to crackle up. With a Bluetooth keyboard or mouse, you start noticing lost characters or jerky motions when you move more than 5 meters from your computer,.
Consumers who want to operate their large screen TV or prefer to hide set-top box out of sight (behind the screen or in the cupboard), will be disappointed in a PAN technology like Bluetooth which loses its reliable connection over a distance.
There was a time that Bluetooth was recommended for wireless Internet (as a LAN technology). It did not have the reliable range and therefore never made it as a LAN.
ZigBee RF4CE is designed for low power and consumes a fraction of the power of traditional Wi-Fi. A remote control can operate on a single coin cell battery for more than 10 years.
This is a big advantage compared to the power hungry Bluetooth, which requires a docking station to keep the internal batteries charged or weekly battery replacements. RF4CE is also much more power efficient than IR, consuming just 25% of the power used by IR solutions.
The Bluetooth industry is working on a Bluetooth LE (low energy) specification, which is in line with the needs for low power sensor applications and could become a candidate for RF remote controls. As Bluetooth is found in many home devices, Bluetooth remotes could be easily linked to Bluetooth headsets, phones, PC, etc. Unfortunately, traditional Bluetooth and Bluetooth LE do not interoperate.
Next week: The RF4CE factor, how it will track your health and find the lost remote.
Cees Links is CEO of GreenPeak Technologies, a Dutch company innovating green, ultra-low power wireless communication technology. www.greenpeak.com