Wi-Fi Alliance: 7 Reasons Wi-Fi Will Succeed in the Smart Grid
My article 5 Reasons Wi-Fi Will Take a Back Seat for the Smart Grid stirred up a lot of debate in wireless circles — while some agreed with it and some pointed out reasons they felt I’d overlooked, others flat-out disagreed with what I wrote. Among them was the Wi-Fi Alliance, the trade group whose white paper I cited in the story. To that end, Greg Ennis, Wi-Fi Alliance’s technical director, presented me with the group’s own list of reasons why, as he put it, “Wi-Fi will succeed for smart grid deployments.” They are:
1. Huge installed base: An estimated 2 billion Wi-Fi chipsets have shipped as of this year. One of every 10 people in the world uses Wi-Fi for work and leisure.
2. Economies of scale: Like many semiconductor-based technologies, the growth in the market for Wi-Fi chipsets has driven increasing volumes and generated lower prices. This year more than 500 million Wi-Fi chipsets will ship and one billion units are expected to ship in 2011.
3. Carriers already deploy it: Worldwide, all major mobile carriers offer WiFi-enabled handsets. Wi-Fi provides the multimedia-rich experience that subscribers want while conserving expensive spectrum. An estimated 80 million WiFi-enabled handsets shipped in 2008; that number is expected to grow to 300 million in 2011.
4. Residential customers love and trust it, and want their smart energy applications to use it: Consumers enjoy the freedom and convenience of Wi-Fi in an impressive array of devices ranging from computers to mobile handsets and a growing range of consumer electronics.
5. Established certification ecosystem and mature industry: The Wi-Fi CERTIFIED designation has been awarded to more than 6,000 devices. The program is recognized as a designator of quality by consumers and across the technology industry. Testing is conducted in 13 authorized test labs around the world.
6. Innovation in low-power silicon: Several new low-power Wi-Fi chipsets are capable of working in very low-power systems. When integrated into a device that optimizes use of the Wi-Fi radio, these chipsets support battery life of up to 10 years in end points such as utility meters.
7. Innovation in distance networking: Existing city-wide Wi-Fi networks include systems that provide access covering up to 500 meters from the AP, interconnected by point-to-point links based on 802.11 technology and using proprietary mesh protocols. Wi-Fi can be used for both neighborhood network access and as part of a wide area network (WAN) backhaul system.
Hi
Below is a comparison of Wi-Fi and Zigbee on various metrics that should be useful:
1: Technology Penetration into Home Products – 2009 (USA)
Wi-Fi: >35% Zigbee: <1%
2: “Number of Certified Products (2009 October)
Source: Wi-Fi Forum Website and Zigbee Forum Website”
Wi-Fi: 6356 Zigbee: <30
3: Band (most used)
Wi-Fi: 2.4-2.5GHz Zigbee: 2.4-2.5GHz
4: Effective Bandwidth / Channel Spacing (most used)
Wi-Fi: 20MHz / 25MHz Zigbee: 3MHz / 5MHz
5: Tolerance of Interference:
Wi-Fi: Good. Wider-bandwidth Spreadspectrum Zigbee: Bad. Narrower-bandwidth Spreadspectrum
6: Tolerance of Multipath – RMS Delay spreads (Implementation dependent)
Wi-Fi: “150ns RMS @ 54Mbps, 500ns RMS @ 1Mbps” Zigbee: 500ns RMS @ 250kbps
7: MAC/PHY Security:
Wi-Fi: WPA/WPA2/CCX are Industry Tested Zigbee: MAC layer security Not available. Relies on Higher layer Security
8: Cost Of solutions:
Wi-Fi: Steadily reducing over years. Single-antenna, Zero-Host, Wi-Fi Chipsets are available today for ~$5 & self-contained modules for ~$10 (including TCP/IP)
Wi-Fi modules inside today’s mobile phones come for less than $4.5 (refer to teardowns e.g,. from isuppli for publicly available information.
Zigbee: Not known
9: Number of Vendors
Wi-Fi: Many Zigbee: Few
10: Data-rate (Max/Typ/Min)
Wi-Fi (b/g): 54Mbps / 36Mbps / 1Mbps
Zigbee: 250kbps alone (Ref: 802.15.4-2006 Section 6.5)
11: Receiver Sensitivity (at Max/Typ/Min data-rates) – Implementation dependent
Wi-Fi (54/36 and 1Mbps) -75dBm / -81dBm / -98dBm
Zigbee (250Kbps) -98dBm
12: Max Packet Length supported
Wi-Fi: 4KBytes (b/g), 64KBytes (n) Zigbee: 127 bytes
13: IP Layer can be directly ported over the MAC?
Wi-Fi: Yes Zigbee: Needs additional layer – 6LowPAN
14: Peak Rx Current @ 3.3V (min/max values for typical implementations in the market)
Wi-Fi: 100 – 200mA Zigbee: 60 – 100mA
15: Peak Tx Current @ 3.3V for 20dBm Tx Power (min/max values for typical implementations in the market)
Wi-Fi: 250 – 350mA Zigbee: 250 – 350mA
16: Shutdown current (min/max values for typical low-power implementations available today)
Wi-Fi: 1 – 5uA Zigbee: 1 – 5uA
17: Energy Efficiency of Reception @ highest datarate (using max values for current consumption)
Wi-Fi: 15nJ / bit Zigbee: 1320nJ/bit
18: Energy Efficiency of Reception @ lowest datarate (using max values for current consumption)
Wi-Fi: 825nJ / bit Zigbee: 1320nJ/bit
19: Does the PHY have error correction coding
Wi-Fi: Yes Zigbee: No
20: Certification for Peer to Peer Low-power operation available?
Wi-Fi: “Yes(Wi-Fi Direct)” Zigbee: Yes
Hope this is useful
Thanks
Partha