Spread Spectrum and mini-vsat Broadband. Presentation to. The Evolution of Satellite Communications Stagparkway

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1 Spread Spectrum and mini-vsat Broadband Presentation to The Evolution of Satellite Communications Stagparkway KVH INDUSTRIES, INC. Mobile Broadband Communications, Guidance & Stabilization

2 Spread Spectrum and mini-vsat Broadband The Evolution of Satellite Communications Executive Summary Many operations today rely on people working from remote locations or while on the move be it an oil-and-gas exploration crew, a homeland defense task force, an emergency response team, or a temporary field office for a global enterprise. With changes in business practices and communications, these mobile workers require a constant connection to home and office. Whether for , video conferencing or other functions, people need to be online in order to conduct business and stay in touch no matter where they may be located. In an effort to make heavy data use affordable to a wide variety of industries, antenna manufacturers and service providers adapted terrestrial VSAT (very small aperture terminal) technology for mobile use. VSAT, with its large antennas and lower-cost service for heavy data use, appeared to offer many markets a more affordable solution. However, the size and cost of 1-meter VSAT antennas limited the use of this technology. Traditional VSAT systems require very large antennas typically in domes a minimum of 48" (1.2 meters) in diameter by 60" (1.5 meters) tall, making them difficult to transport and expensive to install. The bulky equipment and inefficient network technology associated with existing VSAT equipment and services were catalysts for the development of a breakthrough in mobile satellite communications technology: the KVH mini-vsat Broadband sm service and KVH s compatible TracPhone satellite antennas the 24" (60 cm) TracPhone V7 and the 14.5" (37 cm) TracPhone V3. To achieve these groundbreaking reductions in antenna size while not compromising data rates (2 Mbps download) or reliability, KVH and its partner, ViaSat, built the system using ViaSat s patented ArcLight spread spectrum technology. Figure 1: A Comparison of the KVH Spread Spectrum TracPhone V7 and TracPhone V3 vs. Traditional TDMA VSAT Terminal TDMA Traditional VSAT s Solution Traditional VSAT systems historically operate using Time Division Multiple Access (TDMA) technology. Existing 1-meter TDMA VSAT antennas send and receive signals to fixed FSS (Ku-band) satellites that are in geosynchronous orbit and spaced approximately 2 apart in North America, and 3 apart in Europe. These antennas broadcast signals with a high-power spectral density to meet the users bandwidth needs and signal modulation requirements. However, those signals are strong enough that they would disrupt communications from and to Spread Spectrum and mini-vsat Broadband The Evolution of Satellite Communications 1

3 other nearby FSS satellites if the antennas were smaller or aimed incorrectly. In an effort to avoid this interference, regulatory agencies, such as the U.S. Federal Communications Commission (FCC), mandate that existing TDMA VSAT antennas are governed by offaxis emissions that normally require the antenna to point to within 0.2 of the satellite. This level of pointing accuracy requires a large antenna with advanced sensors or sensor inputs, which add to the cost of the system. As a result, these antennas are a minimum of 40" (1 meter) in diameter and housed in domes that are 48" (1.2 meter) in diameter or larger. While it is possible for these traditional systems to operate using smaller antennas, the reduction in transmission power necessary to avoid interfering with adjacent satellites makes the service cost-prohibitive for most consumers and commercial customers. In these systems, less power equals lower bandwidth and reduced data rates, which in turn results in more time spent sending or receiving data, and in the world of satellite communications, time equals money. The reduced antenna size and lower precision would also increase the risk that a smaller standard VSAT antenna would experience interference from broadcasts from adjacent satellites. While there are several variants of TDMA technology, a very commonly used approach fixed-assignment TDMA separates bandwidth into specific frequency bands and then divides these bands into small time slots. Users requests are assigned a slot as they are made (by clicking a link on a web page, for example) and the data transmission is processed when their turn comes up. Separate frequencies and bandwidths are used for the transmitting and receiving channels, and only one subscriber at a time can be assigned a time slot or channel. This means that no other conversations or data can use this channel until the original transmission is finished, effectively limiting the bandwidth available to other users on the network as illustrated in Figure 2. The ratio of users sharing a single source of bandwidth is expressed as the contention ratio (e.g., 10:1). Imagine a 10-lane freeway merging into a single lane at rush hour. Everyone will get through, but each car in each lane must wait its turn. Because fixed-assignment TDMA networks share bandwidth among users, multiple data requests are delayed as they wait Figure 2: Fixed-assignment TDMA divides its bandwidth into time slots, forcing users to compete for space and the opportunity to broadcast data Spread Spectrum and mini-vsat Broadband The Evolution of Satellite Communications 2

4 for a limited number of slots to become available as illustrated in Figure 2. This also creates inconsistencies in data rates, most often leading to customers transmitting at far slower rates than they have paid for with their choice of airtime packages. As the number of users active on the network increases, the contention ratio increases as well, leading to a noticeable slowing of the service s data rates. For instance, a traditional VSAT customer who purchases a plan for a typical advertised speed of 256 Kbps (upload) may end up transmitting at half that speed or slower in reality. A contention ratio of 10:1 means that 10 users may be sharing bandwidth at any one time so you may lose up to 90% of the speed and bandwidth specified in your selected plan. What does this mean to the user? When you click on a hyperlink at home, bandwidth is plentiful and the request is sent instantly. However, when a user clicks on a web hyperlink using a fixed-assignment TDMA network, inbound and outbound data must be synchronized with all other users data being transmitted on the same network. Data transmission rates deteriorate as TDMA traffic jams occur due to transmission bottlenecks. CRMA Technology Why Wait If You Don t Have To? The mini-vsat Broadband service employs ViaSat s unique Code Reuse Multiple Access (CRMA) technology, a proprietary variation on the Code Division Multiple Access (CDMA) approach used by cell phone service providers. The CRMA-based mini-vsat Broadband service significantly reduces contention issues by sending the data to the satellite immediately in a short burst at the fastest possible data rate for the selected service plan, up to 512 Kbps upload and 2 Mbps download. This more efficient transmission and network management scheme ensures that every user on the system enjoys the fastest data rate available in their selected service package even with multiple users transmitting simultaneously. Unlike fixed-assignment TDMA s 10-lane highway narrowing down to a single lane, mini- VSAT offers every user an unobstructed lane for consistent, unimpeded data rates as illustrated in Figure 3. Figure 3: mini-vsat Broadband s CRMA technology transmits a constant stream of data bursts, eliminating delays in transmission and reducing contention Spread Spectrum and mini-vsat Broadband The Evolution of Satellite Communications 3

5 Spread Spectrum Enabling Smaller Antennas and Lower Costs The more modern and efficient spread spectrum technology offers additional benefits to the network and users. By spreading the transmitted signal power over a broader frequency spectrum, it lowers the signal s power spectral density. As a result, it is possible to use smaller antennas with wider beams for two-way VSAT communications, all without interfering with neighboring satellites. For example, a typical 512 Kbps return link carrier occupies approximately 1.2 MHz of bandwidth as illustrated in Figure 4 below. However, only one terminal in a traditional TDMA system can use this frequency at any time. The mini-vsat Broadband approach spreads the transmitted signal power over a frequency spectrum typically 20 times as wide, thereby lowering the signal s power spectral density, shown in Figure 4 below. This same approach has been proven over the last decade by the U.S. military and on business jets. Now, spread spectrum is available for other mobile uses. The mini-vsat Broadband service is also the first mobile service of its kind to utilize hub cancellors at the ground stations. These unique systems enable the service to transmit and receive using the same satellite transponder frequency bands rather than incur the cost and additional bandwidth necessary to send and receive on separate transponder frequencies. The added efficiency resulting from this patented ViaSat technology reduces bandwidth demand by as much as 50%, enabling KVH to offer very affordable service. Together, these factors enable KVH to offer a robust and expandable global broadband network with a range of benefits that can t be matched by traditional network architectures or technology as shown in Table 1 on the following page. Figure 4: TDMA Bandwidth and Spectral Density Figure 5: mini-vsat Broadband s Bandwidth and Spectral Density Spread Spectrum and mini-vsat Broadband The Evolution of Satellite Communications 4

6 And what does this mean in the end? The proven ArcLight technology used by the mini- VSAT Broadband network results in less latency and contention compared to equally sized networks, supports the use of smaller terminals, and reduces overall hardware and service costs. Table 1: Benefits of mini-vsat Broadband CRMA vs. Traditional TDMA Networks More Efficient Transmissions No Contention Worries Supports Small, Powerful Antennas Robust Network Capacity mini-vsat Broadband CRMA Network Burst transmissions enable multiple users to transmit simultaneously and spread signal across entire available bandwidth at highest speed TDMA-style contention eliminated no delays needed between transmissions and channels Military spread spectrum technology designed for exceptional mobile reception/transmission using small antennas System designed for global mobile applications using full transponders in most regions and easily expanded to support subscriber needs Traditional TDMA Networks Signals transmitted only at allotted times with inefficient time buffers between transmissions Time buffers between time slots requires capacity to be further divided into inefficient channels Land-based technology adapted for mobile use with cumbersome, expensive equipment Small, undercapitalized service providers often deploy limited capacity to claim global coverage Find out how the TracPhone V-series and mini-vsat Broadband service can make satellite communications affordable while improving your field operations and expanding your access to the Internet, , company networks, and other mobile communications capabilities. KVH Industries, Inc. World Headquarters Middletown, RI U.S.A. Tel: Fax: KVH Industries A/S EMEA Headquarters Kokkedal, Denmark Tel: Fax: KVH Industries Pte Ltd. Asia-Pacific Headquarters Singapore Tel: Fax: Spread Spectrum and mini-vsat Broadband The Evolution of Satellite Communications 5

7 KVH Industries, Inc. 50 Enterprise Center Middletown, RI U.S.A. Phone: Fax: