FOR OFFICIAL USE ONLY
Wireless Communications Test Bed
Experimentation Plan
Version 0.43
262 January 2004
Prepared Under Subcontract SC03-034-191 with L-3 ComCept, Contract Data Requirements List (CDRL) item A002, WiFi Deployment and Checkout Plan
Prepared by:
Timothy X. Brown, University of Colorado at Boulder
303-492-1630
Kenneth Davey, L-3 ComCept
972-772-7501
FOR OFFICIAL USE ONLY
FOR OFFICIAL USE ONLY
CONTENTS
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Objective 1
1.3 Approach 1
2.0 Test Bed Overview 2
2.1 Test Site 2
2.2 Network Architecture 4
2.3 Equipment 6
2.4 Security 7
3.0 MODES & CONFIGURATIONS 7
3.1 Scenario 1: Ground-UAV-Ground 8
3.2 Scenario 2: Multiple UAVs 8
4.0 MEASURES OF PERFORMANCE & EFFECTIVENESS 9
4.1 Measures of Performance 9
4.2 Measures of Effectiveness 10
5.0 DEMONSTRATION & TEST EXPERIMENTS 10
5.1 Fixed Ground – Fixed Ground 10
5.1.1 Baseline Ground Network 10
5.1.2 Ad Hoc Ground Network Changes 11
5.2 Mobile Ground – Fixed Ground 12
5.2.1 Single Mobile Node 12
5.2.2 Multiple Mobile Nodes 12
5.3 Ground – UAV 12
5.3.1 Fixed Ground-to-Fixed Ground UAV Affects 13
5.3.2 Mobile Ground-to-Fixed Ground UAV Affects 13
5.3.3 UAV Connecting Disconnected Ground Troops 13
5.3.4 UAV Range Ground-to-Air 13
5.4 UAV – UAV 14
5.4.1 UAV Pair 14
5.4.2 Three UAVs 14
5.5 Ground – UAV – UAV 14
6.0 Methods & Procedures 15
6.1 Data Throughput 15
6.2 Latency 15
6.3 Jitter 15
6.4 Packet Loss, Congestion 16
6.5 Packet Loss, Radio 16
6.6 Communication Availability 16
6.7 Remote Connectivity 17
6.8 Hardware Reliability 17
6.9 Range 17
6.10 Network Self-Forming 18
6.11 Node Failure Recovery 18
6.12 Mobility Impact 18
6.13 Data, Voice, Video, Web Page Communication 19
6.14 Deployment & Transportability 19
6.15 Ease of Operation 19
LIST OF FIGURES
Figure Title Page
1 Views of Table Mountain 2
2 Map of Table Mountain 3
3 Network Architecture & Monitoring 4
4 Monitoring Display Example 6
5 Test Bed Scenarios 7
LIST OF TABLES
Table Title Page
1 Ground-UAV-Ground Test Configurations 8
2 Multiple UAV Test Configurations 9
3 Measures of Performance 9
4 Measures of Effectiveness 10
APPENDICES
APPENDIX A – GLOSSARY 20
APPENDIX B – RELATED DOCUMENTS 22
ii
FOR OFFICIAL USE ONLY
FOR OFFICIAL USE ONLY
1 INTRODUCTION
1.1 Background
Communication networks between and through aerial vehicles are a mainstay of current battlefield communications. Present systems use specialized high-cost radios in designated military radio bands. Current aerial vehicles are also high-cost manned or unmanned vehicles.
The ComCept Division of L-3 Communications Corporation has engaged the University of Colorado to design, install and operate a wireless communications test bed made up of Commercial Off-The-Shelf (COTS) equipment, and to integrate and operate Unmanned Aerial Vehicles (UAVs) which will interact with it. The network shall support rapidly deployed mobile troops that may be isolated from each other, allow for ad hoc connectivity, and require broadband connection to a Tactical Operations Center (TOC). Experiments are to be developed to measure the performance and effectiveness of the communications system established. This document details the experimentation plan and procedures.
1.2 Objective
The objective of the wireless communications test-bed effort is to deploy and test a COTS-based communications network made up of terrestrial and aerial nodes that employ state-of-the-art mobile wireless and IP technology. The solution shall support rapid deployment of mobile troops that may be isolated from each other, and require broadband connectivity to a Tactical Operations Center (TOC). Experiments are to demonstrate the potential for rapid deployment of an IP-centric, wireless broadband network that will support both airborne and terrestrial military campaigns anywhere, anytime.
1.3 Approach
A platform supporting the IEEE 802.11b (“WiFi”) industry standard for Wireless Local Area Networks (WLANs) has been chosen as the basis for the test bed due to its support of broadband mobile wireless communications, dynamic ad hoc mesh network operation, and being commercially available at low cost. A common 802.11 platform will be utilized for all ground-based and UAV-based nodes.
The terrestrial and airborne communication devices will form an IP-centric network on an ad hoc basis. Broadband links will be established to a remote TOC location. Remote monitoring capabilities will allow for remote users to access data obtained, and to monitor the test site and activity on a real time basis. Packet data traffic in low, medium, and high-load regimes will be utilized for measuring performance and service support abilities. Typical applications will be demonstrated.
A location has been chosen that allows for uninterrupted testing of multiple deployment scenarios. Baseline performance will be established on a ground-to-ground connected configuration. Mobile node impacts will be tested. UAV deployment will allow for its introduction to the theater to be characterized. UAV effectiveness for connecting isolated troops will be demonstrated, along with UAV abilities to extend the range of communication.
2 Test Bed Overview
An overview of the test site and test bed design is provided in the paragraphs below. For more detailed test bed design information, see the Wireless Communications Test Bed Design document.
2.1 Test Site
The Table Mountain National Radio Quiet Zone (NRQZ) is owned by the Department of Commerce and operated by the Institute for Telecommunication Sciences (ITS) approximately 10 miles north of Boulder, CO. The site is 2.5 miles by 1.5 miles on a raised mesa with no permanent radio transmitters in the vicinity. An aerial photo of the site is shown in 1a and a view at ground level on the top of the mesa is shown in 1b. A map of the site is shown in Figure 2.
(a) (b)
Figure 1: Views of the Table Mountain National Radio Quiet Zone.
Aerial view (a) and ground level view (b).
Figure 2: Map of Table Mountain. The grid lines are 1000ft (300m) spacing. FS1 and FS2 are powered fixed site locations. FS1 also has Internet connectivity. The green line highlights a public road circuit around the base of the mesa.
Table Mountain has several facilities that make it ideal for the wireless test bed needs. First it is a large 2.5sq mi zone where radio communications is controlled. The top is flat and unobstructed. The facility itself is a mountain obstacle suitable for obstructing users on opposite flanks of the mountain as in Scenario 1 in Figure 5. It is circled by public roads so that communication to or from the mountain can be easily set up from any direction. The site has buildings that can house equipment and provide AC power. Finally, it has several areas suitable for UAV flight operations (one is labeled in Figure 2).
2.2 Network Architecture
The network architecture to be used for experimentation and monitoring is shown in 3.
Figure 3: Network Architecture & Monitoring
The test range monitoring will consist of additional software loaded on each ad hoc node. This will collect performance statistics with time and location stamps measured from the GPS. This data is periodically sent to a test bed monitoring gateway. The transfer to the gateway will use the underlying ad hoc network.
The total traffic is expected to be small and not significantly impact the network throughput. Though small, for experimental control, we would like to minimize the monitoring traffic use of the ad hoc network. For this purpose, fixed nodes in the network will also be connected via 802.11 wireless router operating on a different frequency. This separate radio is an Avaya Outdoor Router which is COTS equipment for static network wireless interconnectivity. This will facilitate extracting the monitoring data as quickly as possible from the ad hoc network under test and sending it to the test bed gateway outside of the ad hoc network.
Site Data Gathering:
Each network node collects the following data. The data is then sent periodically to the test bed gateway once every 15 seconds, via fixed sites. Data collected includes:
· GPS Position
· Number of Packets Sent
· Number of Packets Received
· Number of Route Errors
Test Bed Gateway:
The test bed gateway is a laptop computer used as a local collection point for test bed data. It serves as a local Network Operating Center (NOC) for experiment monitoring and control. It is also the source of backhaul traffic to the Monitor Server. Wireless and wired backhaul capabilities will exist.
Monitor Server:
A key aspect to the test bed will be the ability to monitor and collect data from the UAV and ground nodes. Remote monitoring capabilities will be built into the test bed so that remote observers will be able to monitor test bed performance. The pieces to the monitoring include test range monitoring, backhaul to a monitoring server, and a web based interface for remote users.
The Monitor Server is a Sun E250 computer located at the UCB campus. It provides for high-speed web connections; archives experiment data for cross-experiment comparisons and later analysis; and allows for web access to data (live remote and replay of old data).
Remote Monitoring:
The remote monitoring and display capabilities are being designed via a Java interface. The following capabilities are anticipated.
· Situation Map
· Network Status Messages
· Performance Graphs
· Drill-Down on Nodes
Figure 4: Monitoring Display Example
2.3 Equipment
The University of Colorado will provide:
· UAV flight operations equipment.
· Storage, backup, and distribution of software during development.
· Server-class computers for monitor server.
· RF test equipment such as Spectrum Analyzers and Signal generators.
· Wireless table top test bed for early protocol testing.
· 4 cigarette lighter to 110VAC inverters for vehicle mounted radios and other electronics
· 6 Handheld radios for personnel coordination during testing operations.
ComCept will provide:
· Laptops, and desktops for network gateway and for software development.
· Outdoor router equipment for interconnecting fixed sites.
· WLAN cards for wireless network.
· 11 ad hoc radios, 8 ground based, 3 UAV based.
· 2 laptops with large screen for network monitoring.
· 1 Berkeley Varitronics Yellow Jacket WLAN 802.11b analysis tool for physical and MAC layer debugging.
· 2 Sharp Zaurus SL-5600 Linux based PDAs. Smaller personnel carried nodes.
2.4 Security
For the test bed we consider both physical and communication security. The Table Mountain facility is a fenced facility that includes storage and work buildings that can be locked. Equipment such as pole mounted antennas and outdoor routers can be left set up over several days. Portable radios, laptops, and UAV equipment will be stored in on site buildings or carried to and from the site.
To limit access to the wireless communication network, MAC filtering algorithms will be used. The hardware MAC address of every node on the test bed (approximately 20 in total) will be stored on the network devices and only packets that match one of these addresses will be processed. This will prevent casual users from gaining access to the network.
The monitoring server will require a password in order to have access to the remote monitoring facilities.
3 Modes & Configurations
In order for the wireless network solution to be adequately tested for performance and effectiveness against deployment types, the test bed will be configured in multiple ways. Two broad scenarios, shown in Figure 5, will be used for testing the unique 802.11-based network solution.
Multiple configuration types will be involved with each scenario, and are detailed in the following paragraphs. Experimentation techniques for each configuration type and characterization approaches for ease of deployment and operation are detailed in paragraph 5.
3.1 Scenario 1: Ground-UAV-Ground
In Scenario 1, radios on the ground are mounted in vehicles, carried by personal, or placed at fixed sites. The radios implement a wireless ad hoc (aka mesh) network whereby if a traffic source and destination are not in direct communication range, intermediate nodes will automatically relay the traffic from the source to the destination.
This generally provides good connectivity between ground nodes. When nodes become separated by distance or geography, then the network is disconnected. In these situations, the UAV serves as a communication relay between disconnected nodes on the ground. Ground nodes that are isolated from other ground users can reach each other through the UAV.
This scenario will demonstrate that ad hoc networks working with COTS WLAN radios can provide connectivity to widespread units. It will further demonstrate that low-cost UAVs can extend this connectivity over wider ranges and geography than is possible solely among ground units. It will demonstrate typical performance measures such as network throughput, latency, and availability that would be possible with these networks.
The following table lists the test configurations involved with this scenario. Measures of performance and effectiveness are provided in paragraph 2.1.3.
Test ConfigurationsGround—Ground
Ground—Mobile—Ground
Ground—UAV—Ground
Table 1: Ground-UAV-Ground Test Configurations
The purpose of testing ground-to-ground and ground-mobile-ground communication performance and effectiveness is that it provides a baseline for UAV deployment to be measured against.
3.2 Scenario 2: Multiple UAVs
In Scenario 2, we focus on an ad hoc network of UAVs. A UAV is on a long-distance mission. Communication range is limited because of power, weight, and volume constraints on the low-cost, light-weight vehicle. Communication range is extended by using intermediate UAVs to relay back to the control center.