Low Power Wi-Fi
Speaker : Yu-Ping Chen
Advisor : Quincy Wu
Date : 2010/01/17
1
Outline
Introduction to Wi-Fi and IEEE 802.11
 Introduction to Low Power Wi-Fi
 Product of Low Power Wi-Fi
 Comparison between Wi-Fi and Zigbee
 Reference

2
Introduction to Wi-Fi
Wi-Fi technology builds on IEEE 802.11
standards.
 The term Wi-Fi suggests Wireless Fidelity.
 Wi-Fi is a trademark of the Wi-Fi Alliance.
 Wi-Fi Alliance was established in 1999,
when the name was called the Wireless
Ethernet Compatibility Alliance
(WECA). In 2002, officially changed its
name to Wi-Fi Alliance.

3
Introduction to Wi-Fi (cont.)

A huge installed base of over 2 billion
Wi-Fi-certified devices.
--Wi-Fi direct will make Wi-Fi even more
pervasive by turning devices/equipment into
soft AP
There are about 300 members from a
vibrant standard and industry alliance.
 Well-proven encryption, authentication
and end-to-end network security.
 Mature network management systems.

4
Comparison with 802.11
802.11
Protocol
Freq.
(GHz)
Data rate
per stream
(Mbps)
Max
Distance
(indoor)
Max
Distance
(outdoor)
Original
2.4
1-2
15m
40m
802.11a
5
6-54
30m
45m
802.11b
(Wi-Fi)
2.4
5.5-11
30m
100m
802.11g
2.4
6-54
30m
100m
802.11n
2.4 or 5
200-300
50m
300m
The table refers to Wiki.
5
Introduction to Low Power Wi-Fi

High level of integration
-- shorten connections, minimize capacitances
and inductances and reduce overall energy
consumption.

Flexible and rapid power management
-- fast-response states with reduced power
consumption
-- very-low-power Standby or Idle states
6
Introduction Low Power Wi-Fi (cont.)

Transition from low-power states to a
fully operational condition in a short time
-- pre-arranged schedule or by external input.

Minimal current drain for connection
maintenance and device management
7
Typical Low-Power Wi-Fi Operation
8
Low Power Wi-Fi = Standard Wi-Fi, IP
Wi-Fi sensors use IP-over-Ethernet
networking environment .
 Sensor nodes can be managed and
configured remotely using SNMP .
 Support of well proven Wi-Fi link-layer
encryption and authentication and related
Wi-Fi Protected Access (WPA/ WPA2).

9
Low Power Wi-Fi = Standard Wi-Fi, IP
(cont.)

A low-power Wi-Fi device can use the
NAV value received to reduce power
consumption during the requested
interval, and avoid attempting a
transmission which is likely to collide with
that of another Station.
10
Application to Low Power Wi-Fi
Healthcare
 Industrial
 Building Automation
 "Smart Grid" Utilities
 Residential
 Transportation
 Consumer Electronics Remote Control
Products

11
Products of Low Power Wi-Fi
Broadcom BCM4326
 Broadcom BCM4328
 Atech iWEM-1000
 Redpine Signals RS9110-N-11-31
 GainSpan S1010

12
Products of Low Power Wi-Fi (cont.)
GainSpan GS1010

Highly-integrated Wi-Fi SoC – Dual processors,
SRAM, Flash, PA in 10mm * 10mm.
13
Products of Low Power Wi-Fi (cont.)





Ultra low power consumption for years of
battery life on a single AA.
Works with existing Wi-Fi AP infrastructure.
Supports TCP/IP/UDP protocol for direct
internet connectivity.
Enables management, setup and configuration of
device (SNMP).
Delivers Enterprise-level security and reliability
14
Products of Low Power Wi-Fi (cont.)
15
Products of Low Power Wi-Fi (cont.)
Smart power consumption for battery
powered sensors





Efficient active and standby modes
System level power management
Small footprint, real-time OS
Controlled clocking, wakeup
Single die integration
16
Comparison between Wi-Fi and
Zigbee
17
Comparison between Wi-Fi and
Zigbee (cont.)
18
Reference
http://en.wikipedia.org/wiki/Wi-Fi
 http://www.xunzhi.com/low-powerwifi.html
 http://www.prlog.org/10163032-strongmarket-growth-forecast-for-low-powerwifi-in-wireless-sensor-networks.html
 http://www.gainspan.com/
 http://www.wtrs.net/wsntechtrends.htm
 http://en.wikipedia.org/wiki/IEEE_802.11

19
Footprint :這個術語用來描述微型元件
在電腦中佔用更少的空間，以及軟體在
記憶體中（無論隨機存取記憶體或唯讀
記憶體）佔用更少的空間。
 Real-time 作業系統是針對 2 種主要類
型的應用所研發：事件回應 (Event
Response) 與閉迴路控制系統。事件回
應應用，需要一定時間內針對激發所產
生的回應。

back

24