Technical Bulletin

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Technical Bulletin Product Information Overview 2.4-GHz SPREAD SPECTRUM WIRELESS NETWORK May 2001 From the innovators of DISPATCH® 2.4-GHz SPREAD SPECTRUM WIRELESS NETWORK Table of Contents What is the MasterLink™ System?...........................................1 The MasterLink™ System Difference ........................................1 System Components ............................................................2 MasterLink™ 2.4-GHz Mobile Computer System .......................2 MasterLink™ 2.4-GHz Repeater System.................................5 Deploying the MasterLink™ System .........................................7 MasterLink™ System Advantages............................................8 Advantages of DSSS over FHSS ...........................................9 Why Modular’s Design is Superior ......................................10 Specifications ..................................................................10 Radio Channels & Regulations..............................................11 Future Applications............................................................11 Glossary .........................................................................12 Table of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 MasterLink™ 2.4-GHz Wireless Network Overview ........2 Haul Truck Showing Installation of MasterLink™ 2.4-GHz Radios...................................................4 MasterLink™ Hub Installed Inside Haul Truck Cab.........4 MasterLink™ Hub Installed Inside NEMA Box on Mobile Repeater..............................................6 MasterLink™ Mobile Repeater.................................6 Abbreviations and acronyms appearing in this document are defined in the Glossary. MasterLink™ 2.4-GHz Spread Spec trum Wirel ess Net wor k What is the MasterLink™ System? Modular’s MasterLink™ system is a dynamic, new 2.4-GHz spread spectrum wireless communications network for mines. It is designed to significantly increase the amount o f information that can be sent over the radio channel, as compared with 9600-baud narrow-band systems. Using a radio based on Direct Sequence Spread Spectrum (DSSS) at 2.4 GHz, the system attains a 2-Mb/s data rate. This yields an overall performance increase of roughly 50 times over 9600-baud systems. This increase in bandwidth reduces data telemetry congestion in mines with large equipment fleets and enables data-intensive use of the radio channel for graphics, equipment-health diagnostics, equipment location monitoring, high-precision GPS applications—even emerging autonomous truck systems. With MasterLink™, mines can minimize interference, take advantage of the latest mine productivity tools available, and maintain vital communications links between decision-makers and the equipment they monitor and control. The MasterLink™ System Difference The MasterLink™ system’s DSSS technology provides a substantial improvement in signal-to-noise performance over conventional modulation techniques. Operating in the ISM 2.4- to 2.4835-GHz frequency band, the transmitted signal is spread within the frequency domain by using an 11-bit Barker sequence chipping code to obtain a transmission bandwidth of 22 MHz and data rates of 1 Mb/s with DBPSK and 2 Mb/s with DQPSK. The received signal is strengthened by a processing gain of 10.4 dB, thereby increasing the signal’s resistance to interference. This improved radio performance and increased bandwidth provides the wireless capacity for high-value applications that boost mine productivity. MasterLink™ enables: » Intensive use of high-precision GPS applications, which provide realtime distributed data for shovels, loaders, drills, and dozers, as well as mine-wide distribution of original planned and actual topography. » Mobile Foreman applications, with access to current high-precision GPS and dispatching data anywhere, including low-latency DISPATCH® operations. » Interactive maintenance management systems with high-speed, on-line telemetry and use of commercial off-the-shelf (OTS) PCs and handheld computers. May 2001 1 System Components Figure 1 MasterLink™ 2.4-GHz Wireless Network Overview The MasterLink™ system consists of two major subsystems: a 2.4-GHz mobile computer system and a 2.4-GHz repeater system. The primary hardware includes MasterLink™ Hubs, radio-antenna modules, and mobile repeater stations. MasterLink™ uses several small repeaters that are each a fraction of the cost and size of conventional repeater units. Figure 1 shows the typical system architecture. MasterLink™ 2.4-GHz Mobile Computer System Where the application dictates, each truck, shovel, dozer, drill, or other mine equipment in the network requires a mobile computer system. This system consists of: » Two MasterLink™ 2.4-GHz radio-antennas » A MasterLink™ Hub For IntelliMine® applications, including DISPATCH®, a CAN-based Color Graphics console (CGC) and a GPS antenna are essential on mobile units and provide the equipment operator with an intuitive user interface and GPS location, respectively. 2 MasterLink™ 2. 4-GHz S pread Spectrum Wireless Netw ork A unique arrangement using two radio-antennas with patented antenna design provides full 360-degree coverage around mobile equipment. This system design overcomes the practical mounting limitations associated with single-antenna deployment because each radio-antenna provides 190-degree horizontal beam widths that combine to provide comprehensive coverage. Dual radios combat multipath effects in areas where one radio-antenna alone would be unable to receive the signal. Dual radios also enable reception when line-of-sight (LOS) coverage is not possible. On a typical truck installation, for example, the radios are mounted one each on the front left and right corners of the truck (Figure 2). In the dual antenna system utilized by MasterLink™, both radios receive network messages, thereby increasing system reliability through an effective level of redundancy. Intelligent signal detection allows the system to transmit only on the radio-antenna that has optimum transmission to the repeater, ensuring reliable and complete coverage. The MasterLink™ system is compliant with IEEE 802.11 standards. The mobile computer system’s rugged design provides environmental protection against the harsh environments common to mine sites. Both the Hub and radios are watertight and sealed to NEMA standards to protect against such environmental hazards as dust, moisture, and extremes of heat and cold. Shock mounts provide vibration protection. May 2001 3 System Components Figure 2 Haul Truck Showing Installation of MasterLink™ 2.4-GHz Radios The Hub and radio-antenna units are small and lightweight, enabling easy install a ti on on any veh i cl e . Ad d i ti on a lly, the Hub (Figure 3) is s i gn i f i c a n t ly faster than the conven ti onal radio-equipped Hub, providing smoother tra n s i ti on of data, less network con ge s ti on , and increased productivity. Figure 3 MasterLink™ Hub Installed Inside Haul Truck Cab Two digital I/O ports (contact closures) available on the Hub accept discrete inputs from devices such as foot switches or tray-up switches. Status LEDs on the top of the Hub convey important information, such as power, status of both radio-antenna links, GPS availability, and radio communications network status. Additionally, the GPS LED flashes the 4 MasterLink™ 2. 4-GHz S pread Spectrum W ireless Netw ork number of satellites currently being tracked. The LED signal is a convenient visual indicator that provides immediate notice of proper operation and change of status, and allows maintenance personnel to take the appropriate action. This saves time and money by providing a quick diagnostic indication of system performance. The Hub electronics and associated connectors support the following functions: Connector/Ports Quantity Notes 2.4-GHz Radio SLIP Power CAN Reserved GSP Digital I/O 2 1 1 2 1 1 1 GPS RF Input 1 Connectors for 11-Mb/s data link to the radio-antennas Serial port for configuration and update Hub source power (includes accessory switch input) CAN device connections with 24-V power For future “Modular Ready™” interface applications Generic Serial Processor Expansion with 15-V isolated power 2 digital inputs with 24-V wetting voltage for contactclosure-type devices such as foot switches TNC female connector for the GPSantenna MasterLink™ 2.4-GHz Repeater System Rather than installing one or two conventional narrow-band repeaters, the MasterLink™ system uses several small repeaters. The repeaters provide LOS radio coverage within the desired coverage area. Additional repeaters can provide redundancy, improving system reliability. Modular offers a mobile version of the repeater to easily deploy coverage to new work areas. Each repeater extends the base station’s area of coverage and communicates with the base station by way of other repeaters or directly by way of a fiber optic cable, if available. The base station uses redundant radios to ensure continued operation in the event of signal loss. Likewise, primary routing paths between repeaters incorporate alternative routing paths to achieve coverage should a lost signal situation occur. Additional repeaters can be added to provide redundancy to whatever extent is desired. The repeater system consists of: » An environmental enclosure containing a MasterLink™ repeater Hub with a 1-watt, DSSS, 2.4-GHz radio » An omnidirectional 6-dB antenna with a 12-, 18-, or 24-foot mast » A lightning diverter » GPS capability to facilitate system deployment and coverage analysis The repeater Hub resides in a weatherproof enclosure (Figure 4). The entire unit is attached to a support pole with brackets. The electronics are similar to the mobile computer system Hub and reside in a similar enclosure. Both fixed and mobile versions of the 2.4-GHz repeaters are available. The mobile version (Figure 5) permits rapid deployment to achieve additional coverage or improve coverage as the mining progresses. May 2001 5 System Components Figure 4 MasterLink™ Hub Installed Inside NEMA Box on Mobile Repeater Figure 5 MasterLink™ Mobile Repeater 6 Mas terLink™ 2.4-GHz Spread Spectrum W ireles s Network The omnidirectional antenna greatly reduces the need for realignment with changing mine topography. Other options for the repeater system include: » Steel mounting base, including three stabilizing outriggers with adjustable jack stands and a support for the antenna mast, designed to fit the mobile trailer or as a stand-alone fixed unit » Wheel option consisting of a steel frame with two 15-inch wheels and standard trailer hitch that converts the fixed configuration to a mobile configuration The following power options are available for the repeater system: » ac-to-dc power system with surge protector to support 50 and 60 Hz in the 100- to 200-V ac and 200- to 240-V ac ranges » Solar panels, with a 24-V battery backup and surge protection, available in 150- and 300-W power ratings Deploying the MasterLink™ System Installation of the 2.4-GHz MasterLink™ spread spectrum wireless n etwork begins by creating a Digital Elevation software model from mineprovided topology data. Using this model, an LOS analysis is performed to obtain an estimate of the number of repeaters required, and their l oc a ti on s , in order to provide the desired level of covera ge . As a final step, Radio Frequency (RF) prop a ga ti on is mapped, effectively ‘fine-tuning’ the repeater loc a ti on s . Installing the MasterLink™ system hardware on mine equipment consists of installing shock-resistant mounting brackets in pre-designated locations, and then mounting the radio-antennas and Hubs to the brackets. Cables are then routed and the connections are made and checked. Neither the Hub nor radios require being opened. The repeater base and trailer require some assembly; then the antenna mast and brackets are installed. After all the hardware is mounted, cable connections are made and checked. Solar panels charge the batteries in the 24-V solar-powered repeater system until they reach 28.2 to 29.0 V. Note, the batteries must be charged to 25.4 to 26.6 V dc before the load is applied. When the batteries discharge to 22.4 to 23.6 V, the load disconnects. On a fully charged set of batteries, the repeater can continue operating without sunlight for several days. As each mobile computer system and repeater system is installed, operating and application software is downloaded from a laptop through the Hub SLIP port. Then the RF links to the base station or another communications node are checked to verify throughput is acceptable. The status of any and all repeaters in the system configuration can be monitored from the central computer. May 2001 7 MasterLink™ System Advantages DSSS technology at 2.4 GHz is an improvement over the more common FHSS (Frequency Hopping Spread Spectrum) radio. It offers much quicker synchronization time (lock-on), and is also much less suscepti bl e to interference. The range of transmission is substantially greater and it provides a 2-Mb/s data transmission rate. The system provides 1-watt of transmit power, which is 10 times more powerful than most commercially available radios and permits the use of custom 190-degree, horizontal beam width, integrated antennas for fullarea covera ge . The com bi n a ti on of increased power and patented antenna design makes available an 8-mile line-of-sight (LOS) node-to-node range with 10 dB of fade margin in a full 360-degree antenna pattern. Other commercially available radio systems, using high-gain unidirectional antennas, are generally limited to very directional point-to-point links to achieve the same 8-mile ranges. In a typical MasterLink™ system using multiple repeaters, technicians can cascade many 8-mile nodes together on the same network, increasing the effective range even farther. The 2-Mb/s data rate enables data intensive use of the radio channel for graphics, on-line diagnostics, high-precision GPS applications, and the precise data requirements of autonomous truck systems. MasterLink™ is compliant with the IEEE 802.11 standard, a proven protocol, which provides interoperability with other devices, such as a laptop or PDA with a wireless network card; seamless user support for roaming between multiple coverage areas; and high available bandwidth that utilizes a complex collision avoidance scheme, which allows the network to perform well even when the usage is very high. The small Hub size facilitates easy installation in tight quarters. The integrated power protection and distribution scheme with improved shielding provides interference-free and highly reliable operation. Each unit is completely shielded against EMI/RFI (Electromagnetic Interference/Radio Frequency Interference) and includes internal power conditioning and isolation. Installing the MasterLink™ system is expedient, in part, because the system operates in the license-free ISM frequency band. This eliminates the potential delays associated with the radio frequency license application process. Also, there are no licensing fees. The system’s inherent architecture makes adding repeaters to an installed system practically effortless, and mobile repeaters are easily deployed to cover new work areas as the mine’s topography changes. 8 MasterLink™ 2. 4-GH z S pread Spec trum W ireless Network Advantages of DSSS over FHSS The primary benefit of DSSS over FHSS is that it has a significant performance advantage in its power and range capability, which permits the DSSS radio to have more than twice the range and coverage over FHSS. Additional range and coverage means an 8-11 mile range is possible using a 360-degree omnidirectional antenna with DSSS technology. FHSS systems typically lessen range limitation by using directional antennas, which result in a “cone” of coverage that must be directed toward a specific location. This makes full mine coverage with FHSS difficult and requires more repositioning in order to accommodate route changes. Because both technologies are limited to 1-watt of peak output power—most off-the-shelf radios only have 100-mW power— DSSS is the better choice. DSSS also has the capability of higher data rates, faster synchronization to channel changes, and rejection of narrow-band interference. The DSSS radio has the advantage when transferring data because it can chip sequence in just a few bits, whereas an FHSS radio will spend more time to search for the signal and lock on to it, resulting in longer latency time. Modular’s MasterLink™ system with DSSS provides for an additional 10.4 dB of improvement to the SNR (Signal-to-Noise Ratio), which helps get more data through. FHSS does not spread each bit of the signal with a chipping code and thus there is no signal processing gain. Where multiple networks are required, FHSS supports more independent networks than DSSS—thirteen instead of three—and rejects broadband interference better. In an open environment such as a mine, interference should not be a problem for either type of radio system. Moreover, the number of networks located within the mine site is not a significant factor because MasterLink™ with DSSS technology only requires one network (and thus one channel) for operation. Because a mine requires only a single network, DSSS is the ideal choice. Modular chose DSSS technology for its MasterLink™ network to provide the mining industry with the most robust system available that meets the wireless communications needs specific to the mine-site environment. Additionally, DSSS is fast becoming the de facto standard for the wireless communications industry. May 2001 9 MasterLink™ System Advantages Why Modular’s Design is Superior Modular’s MasterLink™ system increases the performance of highprecision applications. With a design based on the IEEE 802.11 standard, MasterLink™ utilizes the strength of a protocol tested and proven throughout the wireless network industry. From the ground up, the system has been engineered to provide best-of-breed integrated technology, a ll owing a mine site to deploy and adjust quickly to changing conditions. MasterLink™ is a fully scalable communications backbone upon which your mine’s network system can grow. As the industry leader in mine management technology, with over 20 years of experience in the mining industry, Modular con ti nues to provide proven reliability and cost-saving solutions. We stand behind our products. The MasterLink™ system is designed to withstand worst-case mining conditions in some of the roughest environments in the world, and it is customizable for each site. Specifications REPEATER SYSTEM TYPICAL UNITS Power Inputs (from solar array or ac/dc converter) Solar Panel Power Rating Power Requirement Mast Height Options 24 (nominal) 150 or 300 24 12, 18, or 24 volts dc watts volts dc feet MOBILE COMMUNICATIONS SYSTEM TYPICAL UNITS Voltage Input Range Power Usage Radio Dimensions Radio Weight Hub Dimensions Hub Weight Operating Temperature Range 12 or 24 (nominal) 20 to 50 8.7 X 6.5 X 13.5 3.5 14.0 X 10.3 X 3.7 9.5 -30 to +70 volts dc watts inches pounds inches pounds Celsius RADIO OPERATION & PERFORMANCE TYPICAL UNITS Output Power Range (8 Bit DAC = 256 steps) TX Distance Range (set to 30 dBm) B.E.R. (Bit Error Rate) Receiver Sensitivity ( = Noise Floor + SNR) Dynamic Range (TX PWR - Receiver Sensitivity) TX & RX Data Rates using DQPSK TX & RX Data Rates using DBPSK Chipping Code Data Scrambling Antenna gain 2-30 8.0 1 X 10 -6 -92.87 122.87 2 1 11 Enabled 6 dBm miles bits dBm dB Mb/s Mb/s bits dB (360-degree horizontal coverage mobile repeater) 10 MasterLink ™ 2. 4-GH z S pread Spectrum Wireless Network Radio Channels & Regulations USA: ISM BAND Power 2400 - 2483.5 MHz (same for Europe – ETSI) 1-watt maximum (30 dBm) for DSSS with 6 dB of antenna gain JAPAN: ISM BAND Power 2400 – 2497 MHz 10 mW / MHz Regulatory Domains The radio system operates on any legal channel on a mineby-mine basis (completely at the customers’ discretion). With this multichannel capability, a mine could operate a separate and independent system using another channel. The transmit spectrum bandwidth of a channel is 17 MHz centered on the channel frequency. ID Frequency (MHz) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 2467 2472 2484 X'10' FCC X'20' IC X'30' ETSI X'31' X'32' X'40' MKK U.S.A. Canada Europe Spain France Japan X X X X X X X X X X X - X X X X X X X X X X X - X X X X X X X X X X X X X - X X - X X X X - X X X X X X X X X X X X X X As of April 2001. Please contact your local regulatory domain agency for the most up-to-date information. Future Applications With the MasterLink™ system, the future is wide open. Consider the possibilities for additional service applications to improve mine-site productivity, such as IP addressing, improved routing, and Object Messaging (OMS), all of which will greatly improve how data moves through the site and potentially provide an integral link to outside networks and the Internet. Imagine e-mail and messaging services built in to the system, intranet and Internet connectivity that enables access to account information from your vendor and OEM sites, or access to corporate enterprise data. Would you like to be able to predict when a part will fail, enabling repairs to be scheduled well in advance of a complete breakdown, thereby, saving time and reducing costly replacements that may not be necessary? Envision your mine site running on Autonomous Haulage, or obtaining data from the site on your handheld computer or PDA (Personal Digital Assistant) without ‘plugging in.’ These are only some of the future applications that may become commonplace over the next decade. What does the future hold? No one knows for certain, but Modular will be there continuing to offer innovative solutions and cutting-edge technology that provide mine sites across the world with increased cost savings and a maximized return on investment. We find the prospects exciting! Want to come with us? What will the future be like at your mine site? May 2001 11 Glossary Autonomous Haulage The navi ga ti on of an unmanned vehicle using position-based path tracking. Modular’s Autonomous Haulage project utilizes the IntelliMine® mine management system, including DISPATCH®, to act as the real-time supervisory system for unmanned haul trucks. Barker Sequence The 11-bit chipping code required for compliance with the IEEE 802.11 standard for wireless LANs. Baud A measure of the number of times per second a signal in a communications channel varies. BER Bit Error Rate. CAN Controller Area Network. CGC Color Graphics Console. Chipping Code A particular bit pattern in which each transmitted bit is multiplied. This bit pattern (or binary sequ en ce) spreads the transmitted signal over a wide frequency range. The receiver uses the same chipping code to reconstruct the original signal. This reconstruction provides the 10.4-dB processing gain. DAC Digital-to-Analog Converter. dB Decibel; a logarithmic unit used to express the relative difference in power usually between acoustics or electric signals. DISPATCH® The only truly proven dispatching system. Created by Modular, it integrates the complete mining process by providing automatic, optimized haul truck assignments. DBPSK Differential Binary Phase Shift Keying, supports 1-Mb/s data ra te . DQPSK Differential Quadrature Phase Shift Keying, supports 2-Mb/s data rate. DSSS Direct Sequ en ce Spread Spectrum. A form of spread spectrum technology that uses a very fast binary bit stream (chipping code) to multiply (or mix) against a modulated RF data signal. The process splits each bit of transmitted data into many fra gm en t s , which results in the signal being spread over a much wider frequency band. This results in a much more robust and interference-resistant signal than the original, unspre ad ,m odulated, RF data signal. EMI/RFI Electromagnetic Interference / Radio Frequency Interference. FHSS Frequency Hopping Spread Spectrum.A form of spread spectrum technology that relies on ‘hopping’ between channels, using different carrier frequencies at different times. The data signal is modulated with a narrowband c a rrier signal that ‘hops’ in a random but known sequence from frequency to frequency as a function of time. GHz Giga-hertz; one billion cycles per second. GPS Global Positioning System. Developed by the United States Department of Defense to simplify accurate navi ga ti on . It uses satellites and computers to calculate precise positions on Earth. GSP 12 Generic Serial Processor. A built-in component of Modular’s IntelliMine® and DISPATCH® systems that provide the serial communications interface to third-party health-monitoring devices. MasterLink™ 2.4-GH z S pread Spec trum W ireless Network IEEE Institute of Electrical and Electronics Engineers. Founded in 1884, the IEEE is an organization composed of en gi n eers, scientists, and students. Best known for developing standards for the computer and electronics industry, in particular, the IEEE 802 standards for local area and wireless networks. IntelliMine® Modular’s innovative mine management system that optimizes the performance of a mine’s critical assets. IntelliMine® incorporates Modular’s world-renowned DISPATCH® system and is the only ful ly integrated system available for both open pit and underground operations. ISM Industrial, Scientific, and Medical bands. An FCC modification of part 15 of the radio code that authorized license-free operation in the following ISM bands: 902 - 928 MHz, 2.4 - 2.4835 GHz, and 5.725 - 5.850 GHz. LED Light-Emitting Diode. LOS Line-of-Sight. Mb/s Megabits per second; a data rate. One million bits per second. MHz Multipath Mega-hertz; one million cycles per second. Interference caused by reflected GPS signals arriving at the receiver, typically as a result of nearby structures or other reflective surfaces. Signals traveling longer paths produce higher (erroneous) pseudorange estimates and, consequently, positioning errors. NEMA National Electrical Manufacturer’s Association. OTS Off-the-Shelf. PDA Personal Digital Assistant. PN PWR Pseudo Noise. A digital signal with noise-like properties. Also a wideband modulation, which imparts noise-like characteristics to an RF signal. Power. Real time Real-time communications in which information sent is received instantly by the other party in a continuous stream. For example, telephone calls are real time; e-mails are not. RF Radio Frequency. Generally a frequency from 50 kHz to 3 GHz. RF is normally referenced whenever a signal is r adiated through the air. RX Receive. SLIP Serial Line Interface Protocol. Serial port on the Hub for configuration and update. SNR Signal-to-Noise Ratio. Spread Spectrum An RF modulation technique. Spreads a signal bandwidth over a wide range of frequencies for transmission, and then de-spreads it to the original data bandwidth at the receiver. Synchronization time TNC TX The time it takes to lo ck on to and begin receiving a signal. Threaded Normalized Connector. Transmission or transmit. May 2001 13 for further information: Modular Mining Systems, Inc. 3289 E. Hemisphere Loop Tucson, AZ 85706-5028 U.S.A. tel: +1 (520) 746-9127 fax: +1 (520) 889-5790 www.modularmining.com Every effort has been made to provide reliable results regarding information comparing Modular’s technology and/or products with competitive offering(s). In addition, wherever possible, the latest available specification sheets and other material have been used, with the full understanding that these are subject to change without notice. This document may contain forward-looking statements. This document is the sole property of Modular Mining Systems, Inc. Any reproduction of this release (or other copyrighted material) without the foregoing explanation and express permission of Modular Mining Systems, Inc. is prohibited. ©2001 Modular Mining Systems, Inc. All other trademarks are the property of their respective owners. TB-MLSU-US-01-r1 May 2001 Printed in U.S.A.