1. One Laptop Per Child All you need to know about site surveys 1

2. XO laptop Communication models 1. With no infrastructure – simple mesh:  This is also known as “a group of kids sitting under a tree”.  No access point (or any other network infrastructure).  No school server (presence server).  Currently supports up to 10 laptops in this scenario. Please be aware that ALL XO’s in the area will become part of this mesh, NOT just those who are actively collaborating. 2

3. XO laptop Communication models 2. Simple Wi-Fi – No school server:  Uses traditional 802.11b/g access points  No school server (or presence service)  Traditional APs tend not to handle multicast very well, 1Mbit/s peak. 3

4. XO laptop Communication models 3. School Wi-Fi:  This is the network configuration we currently suggest for schools.  Uses traditional 802.11b/g access points.  School server with presence service.  The connection to the Internet is optional, but strongly recommended. 4

5. What is a site survey? Definition: A wireless site survey is the process of planning and designing a wireless network, to provide a wireless solution that will deliver the required wireless coverage, data rates, network capacity, roaming capability and quality of service. A site survey should be performed by a Certified Wireless Network Professional - CWNP. (Visit www.cwnp.com for more information).www.cwnp.com Tools: Laptop computer, digital camera, binoculars, GPS, compass, inclinometer, RF spectrum analyzer, antenna, cable, measuring tape, flash light, safety equipment (hard hat, climbing harness, safety glasses, hearing protection, etc.). For additional information about the radio spectrum, please visit: http://www.fcc.gov/oet/spectrum/http://www.fcc.gov/oet/spectrum/ 5

6. Site survey objectives  To gather enough information to determine the number and placement of access points that provides adequate coverage throughout the facility.  To understand the behavior of radio waves within the facility and potential interference from other sources that could degrade performance, before installing the wireless network access points (AP’s).  To anticipate performance and troubleshoot potential problems.  To determine the list of required equipment and materials needed to address the defined requirements.  To understand the school’s wireless requirements (e.g., number of classrooms, number of students with XO’s, number of school floors), and the location of the school Wi-Fi enabled server(s).  To build an accurate map of the physical facility (e.g., the school).  To gather all the information needed to design a cost-effective WLAN that is highly available, scalable, manageable and inter-operable. Notes: This document assumes that broadband Internet service is available within the school(s). 6

7. 10 Steps for a successful site survey Determine the state of Internet access. If a school is already Internet-ready (e.g., broadband service is available), then the site survey is greatly simplified. If not, a plan will need to be put in place to bring Internet access into the schools via DSL, satellite or point-to-point wireless LAN. Obtain a school diagram/blueprint. Before getting too far with the site survey, locate a set of the school’s blueprints. If none are available, prepare a floor plan drawing that depicts the location of walls, walkways, classrooms, etc. Visually inspect the facility. Walk through the school before performing any tests to verify the accuracy of the school diagram. Note any potential barriers that may affect the propagation of RF signals. Perform Radio Frequency (RF) spectrum analysis. Because wireless networks operate in unlicensed frequencies, potential interference from numerous devices such as microwaves, cordless phones, Bluetooth devices, video cameras, etc. can have a significant negative impact. Compile a log of signal readings for future analysis. This analysis will help in understanding how doors, walls, elevator shafts, people and other hardware may affect the AP’s radio frequency pattern. 7

8. 10 Steps for a successful site survey (cont..) Identify user areas. On the school diagram, mark the areas of fixed and mobile users. In addition to illustrating where the children will use the XO’s, indicate where they will not go. You might get by with fewer access points if you can limit the roaming areas. Estimate the total number of AP’s needed for overall coverage and determine their preliminary locations. OLPC recommends one AP per every 50 XO laptops when there is a server present. One AP can cover a circle within a 100-foot radius. Determine the best place to locate AP’s based on the results of the RF spectrum analysis and on available power and cabling to connect to the rest of the network. Verify access point locations. Install an access point at each preliminary location, and monitor the site survey readings by walking varying distances away from the access point. Document findings. Once you're satisfied that the planned location of access points will provide adequate coverage, identify on the school diagrams recommended mounting locations. Also, provide a log of signal readings and supported data rates near the outer propagation boundary of each access point as a basis for future redesign efforts. 8

9. Prepare final report. The result of a site survey is a final report that contains detailed information that addresses coverage, interference sources, equipment placement, power considerations and wiring requirements. It includes a hardware list, where to install the products, the configuration of the devices, and suggested antenna placement for each device. It serves as a guide for network design and for the installation and performance verification of the wireless communications infrastructure. Design Bill of Materials (BOM). The BOM is made of a hardware list of all the Wi-Fi equipment that will be part of the school’s WLAN. It includes part description, part number and unit price. It also includes a quotation for total hardware cost and a quotation for installation. 10 Steps for a successful site survey (cont..) 9

10. Types of site surveys  An active or live survey uses an actively transmitting AP and a Wi-Fi-enabled laptop to measure Wi-Fi signal strength from the AP in the school to determine coverage, performance, how many APs are required, and where they will be installed.  A predictive or virtual survey uses a software package to simulate the construction of the school. Floor plans of the school are imported into the tool and enable the determination of attenuation values (how much RF energy is absorbed) for walls, floors, cubicles, windows and other objects in the building. The application will then predict the number and location of APs required to meet the desired coverage and performance goals. 10

11.  What types of structures or mountings will be needed for antennas.  The location of radio equipment and how it will be mounted.  The presence of potential interference sources.  What type of power will be used.  Grounding & lightning protection methods and locations.  How and what type of cable(s) will egress structures.  Lengths of all cables.  Procedures for site access, getting antennas and mounts to proper locations.  A list of tools and materials needed during installation.  List of required equipment (and estimated costs). The final report should tell you: 11

12.  The Marina Orth school is located in a rural area, outside the city of Medellin, Colombia. There are 14 teachers and 215 students. All of them have received an XO laptop.  75% of the students who have received laptops live in a radius of 3 kilometers from the school. The other 25% live in a radius of 5 kilometers from the school.  This is the first rural, public, bilingual educational center in the City of Medellin with a heavy emphasis on technology. Case study: Marina Orth school Children at the Marina Orth School show their excitement after receiving their XO’s 12

13.  Motorola is providing a turnkey WLAN solution for the school including connection to the Internet Service Provider (ISP). This solution will enable: 1.Point-top-point connection between school and ISP 2.Individual laptops to communicate outside the school via mesh network 3.Laptops to link-up with Wi-Fi AP inside school  The site survey conducted by a Motorola Certified Network Engineer, indicated that the indoors/outdoors solution should include the following key equipment: Wi-Fi Mesh solution: 8 2.4 GHz and 4 5.8 GHz antennas Mesh manager software Canopy solution, that allows point-to-point connection between the school ISP: 6 5.4 GHz backhaul (no reflector) 2 5.2 GHz backhaul – Extended range Wireless LAN: 1 wireless switch (integrated router, gateway, firewall and power-over-Ethernet 6 Access ports (AP) with integrated dual 2.4GHZ and 5GHZ antennas Case study: Marina Orth school (Cont..) 13

14.  The indoors/outdoors Wi-Fi LAN solution provided by Motorola is depicted in this diagram: Case study: Marina Orth school (cont..) 14

15. Final thoughts  It will be the Country’s/NGO’s responsibility to plan for the completion of a site survey and utilize a local Certified Network Engineer, or hire one if this role does not exist within the Ministry of Education/School System, who will carry out the site survey.  A country/NGO will need to purchase equipment and related materials on their own. Brightstar can support this by providing quotations for servers and wireless infrastructure and supply them as needed.  The schools need to define their requirements to include what they want to do. E.g. connect to the Internet, collaborate between XO’s, connect to a school server, provide coverage to the school only vs. school and homes, and any other details on what they will use the network for. For questions concerning wireless infrastructure deployment, please contact: http://lists.laptop.org/listinfo/networking at OLPC.http://lists.laptop.org/listinfo/networking 15

16.  Wi-Fi: Short for “wireless fidelity”. It is the brand name of a popular network technology that provides wireless high-speed Internet and network connections. It is made of WLAN products that are based on the Institute of Electrical and Electronics Engineers‘ (IEEE) 802.11 standards.  WLAN: Acronym for Wireless Local Area Network. Also referred to as LAWN (Local Area Wireless Network). A type of local-area network that uses high-frequency radio waves rather than wires to communicate between nodes.  Wi-Fi Alliance: Organization that oversees tests that certify product interoperability. A product that passes the Alliance’s tests is given the label "Wi-Fi certified" (a registered trademark).  Signal-to-Noise Ratio (SNR): It is the signal level (in dBm) minus the noise level (in dBm). SNR directly impacts the performance of a wireless LAN connection. A higher SNR value means that the signal strength is stronger in relation to the noise levels, which allows higher data rates and fewer retransmissions – all of which offers better throughput.  Mbps: Mbps stands for millions of bits per second or megabits per second and is a measure of bandwidth (the total information flow over a given time) on a telecommunications medium. Site survey terminology 16

17.  ‘Hot Spot’: A location that offers public access to a Wi-Fi network.  Line-of-Sight: LOS is the process of directing our sight along a line in the direction of an object. It is a rather simple principle: In order to view an object, you must sight along a line at that object, and when you do, light will come from that object to your eye along the line of sight.  IEEE: Institute of Electrical & Electronics Engineers, a non-profit organization. IEEE is the world’s leading professional association for the advancement of Technology. The IEEE’s 802.11 & 802.11x standards refers to a family of specifications developed by the IEEE for wireless LAN technology in the 5GHz and 2.4GHz public spectrum bands. 802.11: Applies to wireless LAN and provides 1 or 2 Mbps transmission in the 2.4 GHZ band. 802.11a: It is an extension of 802.11 that applies to wireless LAN and provides up to 54 Mbps in the 5 GHZ band. 802.11b: Up to 11 Mbps in the 2.4 GHz band. 802.11g: Up to 54 Mbps in the 2.4 GHz band. Site survey terminology (cont..) 17