Slide 1

Kevin Fall Intel Labs, Berkeley Microsoft Connecting the Next Billion Workshop 28/29-Aug-2010 Agra, India kfall@intel.com 1 Developing Long Distance WiFi for Rural and Developing World applications

Slide 2

A Parallel Effort at Intel / UCB 2 Timeframe: 2005-2009 [mostly 05-08] UC Berkeley: students doing WiLD research Intel: collaborators building product in parallel Quick Summary: UCB: Algorithms and s/w prototype on x86 platform NSDI WiLDNet Paper UCB: Algorithms and hw/sw prototype on ARM Rural Connectivity Platform (RCP) Product (Zcom) Some other work as well

Slide 3

Why WiFi 3 Widely understood / deployed system Inexpensive, high-power hardware Compatible directional antennas Unlicensed operation Some alternative spectrum options (depends on vendor) Ability to be coupled with embedded PC Opportunity for innovation and research Of interest to Intel and TIER project Used in p2p and p2p-multihop setups

Slide 4

Why Not WiFi 4 Designed for office environment Stop-and-wait (ACKs): degrades tput w/dist Unnecessary beacon/join protocol Resists interference poorly CSMA/CA with CCA is conservative [low tput] Interference from nearby devices Driver guts are proprietary Limits innovation opportunities / research Setup/maintenance can be challenging

Slide 5

Recommended Solutions 5 Switch from Stop-and-Wait to selective ACK / repeat (bulk ACKs) improve channel utilization Switch from CSMA/CA (DCF) to slotted TDMA Also disable CCA no interference (but not so friendly) Can use SW (OS) timer or HW (based on beacon) Modify mgmt frames to disable random association, select master and timing info Use simultaneous xmit across devices at multi-hop nodes (idea from 2P protocol) FEC or other error control sometimes useful

Slide 6

What is the RCP? 6 IP Router and Application Server Intel IXP 425 network processor Atheros-based 802.11 a/b/g mini-PCI cards 512 MB compact flash storage customized Linux OS (later, FreeBSD) outdoor enclosure Antennas Power supply using PoE

Slide 7

The Base Hardware 7 Gateworks Avila GW2348-4 Intel IXP 425/533 Mhz 64MB SDRAM/16MB Intel Strataflash 4x Type III mini-PCI [4.5 W avail to each] 2x 10/100 Wired Ethernet compact flash socket 1KB serial EEPROM, GPIO battery backed-up RTC voltage/temp monitor available to software watchdog timer thermally-activated fan controller 9-48VC via PoE or connector ; 5W typical -40C to +85C operating temp range

Slide 8

Hardware Additions/Mods 8 Senao/Engenius NMP8602+ (later Ubiquiti cards) mini-PCI 802.11 a/b/g up to 400mW xmit power -98dB recv sensitivity 2x U.FL antenna connectors Atheros AR5006 (AR5414) chipset 0C-+55C operating range -20C +70C storage range Base hardware mod PoE on both Ethernet

Slide 9

The Box 9 Outdoor enclosure based on WRAP box www.mini-box.com modified by Gateworks paint 4x N holes, connector/pigtails mounting plate fan weatherized connector housings

Slide 10

Box on Pole 10

Slide 11

The Software 11 Development platform started with uCLinux Extensive modifications special hw-based TDMA WiFi driver autoconfiguration and set-up web gui remote firmware upgrade/install Provides p2p link, AP capability, time synchronization, DHCP, DNS, NAT Experimental multicast version of dnsmasq find which RCP device has this address please

Slide 12

12

Slide 13

HW Prices [retail, low qty] 13 Boards: $284, WiFi: 2x$86 Cases: $160, Power Injector: $29 Total:$645 Does not include antennas, which vary: rubber duck: $15 directional: $50-$100 omni: $30-$80

Slide 14

And Finally to Product 14 Zcom ZC-3625-5-23 and ZC-3625-55-23 Overview Designed for outdoor environment application, Value series ZC-3625-5-23 wireless professional equipment adopts Intel RCP concept to provide an affordable and reliable rural connectivity solution. With rigorous design: IP67 watertight enclosure, Level 17 Beaufort Scale and high reliability surge protection, it provides high reliable, stable transmission and outstanding performance in almost any harsh outdoor environment.

Slide 15

Splashpage 15

Slide 16

Some Learnings 16 Research experimentation and prototype difficult to share as target for product development Auto-configuration and GUI challenges not to be underestimated Remote update / recovery is crucial Power, poles, antennas and deployment can be tricky Many people are conditioned to know WiFi is office only

Slide 17

Future Possibilities (we didnt pursue) 17 Ad-Hoc/Mesh Operation IPv6 beyond 802.11 a/b/g Security beyond WPA2 Antenna / aiming wizard & guide Other languages Audio (e.g., for help & alignment) Services: cache, sip

Slide 18

Thanks / Credits 18 Eric Brewer and TIER group (UC Berkeley) Sam Leffler (contractor, now at Google) Matt Podolsky (contractor, now at UC Berkeley ) Willy Agatstein, Jeff Galinovsky, Tony Salvador, Larry Carr, David Sidhu, Albert Teng (some formerly Intel/EMPG) Alan Mainwaring (Intel Labs Berkeley) Ron Eisworth (Gateworks) Thanks for listening

Slide 19

Backups 19

Slide 20

20

Slide 21

21

Slide 22

22

Slide 23

23