TV White Space / Super Wi-Fi for Broadband Wireless Access Issue Rev 1.0 Date 2018-09-21 Aviacomm, Inc.
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Table of Contents 1. Executive Summary...4 2. Overview...5 2.1 The Economics of Internet Connectivity by TVWS... 5 2.2 Regulatory Requirements... 6 2.3 Spectrum Details... 6 2.4 Advantages of TVWS / Super Wi-Fi... 8 3. The Uses of Super Wi-Fi... 10 4. Super Wi-Fi Network Deployment... 11 4.1 Scenario I... 11 4.2 Scenario II... 12 5. Case Example - Rural Internet Access in China... 13 6. Aviacomm Example Reference Modem ADK300... 14 7. Table of Acronyms and Abbreviations... 15 Aviacomm Inc. Page 3
1. Executive Summary TV White Space (TVWS), also called Super Wi-Fi, is the term for TV broadcast channels that are purposefully unused in specific regions to serve as guard bands to prevent TV signal interference. Under newly created and adopted regulatory rules, these TV channels maybe used by Wireless Internet Service Providers (WISPs) to supply two-way broadband Internet access. Modems that use TVWS spectrum are called TV band devices (TVBD). The benefit of using TVWS spectrum for wireless internet connectivity is multifold: TVWS modems use free unlicensed spectrum, unlike cellular modems that uses high-cost licensed spectrum In rural areas, dozens of TV channels are commonly available, enabling 100 s of Megabits per second (Mbps) of through-put capacity Regulatory rules permit systems capable of transmitting signals over many kilometers In comparison to wireless systems that utilize 2.4/5GHz WiFi unlicensed spectrum, sub-1ghz TVWS signals naturally propagate further and penetrate walls and trees better. These non-line-of-sight properties enable simplified and lower cost deployment. Aviacomm Inc. Page 4
2. Overview 2.1 The Economics of Internet Connectivity by TVWS A study by the Boston Consulting Group concluded that TVWS is the most economical technology for delivering Internet access to rural communities. A combination of technologies can substantially reduce the total cost of extending broadband coverage. TV white space is expected to provide the best approach to reach approximately 80 percent of this underserved rural population. 1 The chart below shows the broad range of communities that could benefit from affordable TVWS-based Internet access. 1 https://blogs.microsoft.com/uploads/2017/07/rural-broadband-strategy-microsoft-whitepaper -FINAL-7-10-17.pdf Aviacomm Inc. Page 5
2.2 Regulatory Requirements TV White Space / Super Wi-Fi for Broadband Wireless Access The Dynamic Spectrum Alliance (DSA) developed and published model rules that regulatory agencies around the world can use to enable this market. These rules cover the following issues: 2 WISPs use this spectrum on a shared secondary-user basis TVWS Access Points determine TV channel availability by checking a geolocation data base TV band devices must meet transmit spectral mask requirements to prevent interfering with TV broadcast receivers (called protected entities ) 2.3 Spectrum Details Television Broadcast frequency channels were standardized and licensed to broadcasters years ago, assigned in 6, 7, or 8MHz bandwidth increments (depending on the country s preferred video encoding scheme). The FCC in the United States adopted the NTSC broadcast standard that required 6MHz channels, which is the standard used in much of the Americas. Other countries utilized PAL or SECAM standards that require 7 or 8MHz of spectrum per broadcast channel. TVWS devices use 6, 7, or 8MHz bandwidth channels (or combined channels for higher throughput) over the frequency bands from 470MHz up to about 800MHz. 2 http://dynamicspectrumalliance.org/regulations/ Aviacomm Inc. Page 6
A summary of allocated TVWS regulation status, channels size, and frequency allocation in various countries is shown in the table below. 3 In densely populated urban areas, most TV broadcast channels are heavily utilized, often with only a few channels available for unlicensed shared use. In contrast, rural areas offer dozens of available TV broadcast channels, enabling 100 s of Mbps of Internet capacity. Country Regulation Status Channel Size Freq Start (MHz) Canada Published 6MHz 470 Freq End (MHz) Currently 698MHz, pending on 600MHz band status Mozambique Draft 8MHz 470 694 New Zealand unknown 8MHz 470 790 Singapore Active 8MHz 470 806 South Africa Published 8MHz 470 694 United Kingdom Active 8MHz 470 790 United States Active 6MHz 470 614 Colombia Published 6MHz 470 698 Trinidad and Tobago Published 6 MHz 470 698 South Korea Published 6 MHz 470 698 3 Country TVWS status table provided by Nominet. Aviacomm Inc. Page 7
2.4 Advantages of TVWS / Super Wi-Fi TV White Space / Super Wi-Fi for Broadband Wireless Access The IEEE defined an industry standard for TVWS called IEEE 802.11af, which is part of the Wi-Fi family. Since 802.11af uses lower frequencies (470 ~ 800 MHz) than the traditional Wi-Fi frequencies (2.5GHz or 5GHz), it achieves much better signal propagation performance. For this reason the 802.11af TVWS standard is also called Super Wi-Fi. The diagrams below illustrate Super Wi-Fi s coverage and propagation advantage compared to traditional Wi-Fi: Aviacomm Inc. Page 8
The lower frequencies used by Super Wi-Fi enable superior RF non-line-of-sight coverage, as shown in the illustration below. Fewer Super Wi-Fi Access Points are needed to cover the same geographic area compared to traditional Wi-Fi solutions. Super Wi-Fi antennas may be located at lower heights, saving on the cost of tall metal towers. Aviacomm Inc. Page 9
3. The Uses of Super Wi-Fi While Super Wi-Fi can be used for Internet access like Wi-Fi, although with better coverage, Super Wi-Fi can also be used for many other applications. The illustration below shows examples for other possible uses, such as IoT, smart city, video surveillance, transportation, etc. The non-line-of-sight performance of Super Wi-Fi makes it uniquely capable of meeting some connectivity requirements, e.g., inside large warehouses or cargo areas, or outside where significant trees or hills are present. Aviacomm Inc. Page 10
4. Super Wi-Fi Network Deployment 4.1 Scenario I The diagram below shows a typical example of a Super Wi-Fi network plan at a regional level which is used primarily as wireless backhaul connections for Wi-Fi hot spots. (This diagram is for illustrative purpose: exact details need to be worked out through wireless network planning by a network operator.) Aviacomm Inc. Page 11
4.2 Scenario II The diagram below shows the scenario in which Super Wi-Fi is used for a direct connection to home users. Aviacomm Inc. Page 12
5 Case Example - Rural Internet Access in China The real case example shown below is for a TVWS field trial in Shandong and Sichuan, China. The user terminal in this market trial is based on the ADK300 which was developed by Aviacomm s ecosystem partner, using Aviacomm s chipset and reference design. Aviacomm Inc. Page 13
6 Aviacomm Example Reference Modem ADK300 The ADK300 TVWS / Super Wi-Fi modem in the photos below was developed by Aviacomm s ecosystem partner, using Aviacomm s chipset and reference design. CPU Item External Interfaces Memory PA Connectors and Buttons Dimensions Environmental Descriptions MediaTek MT7628A (MIPS24KEc CPU with 575/580MHz) Wi-Fi :IEEE 802.11af standards Supported 1x1 mode with 35.6Mbps PHY rate at 8MHz Channel ; 26.7Mbps PHY rate at 6MHz and 7MHz Channel Antenna : support Wi-Fi internal antenna LAN Ethernet Ports : 1 x 10/100Mbps RJ45 Port Flash : 16MBytes; DDR2: 64MBytes Wi-Fi : External PA with 20dBm RF Power 4x (G) LED activity indicators ; 1x WPS Button; 1x Reset Button Plastic Enclosure: no need. Operating Temperature: 0 ~ 40 degree C The ADK300 Modem uses Aviacomm s ARF3018 high-performance RF CMOS Integrated transceiver which was specially designed to meet the high-linearity requirements of TVWS RF systems. The 802.11af baseband processor was developed by an ecosystem partner. The ADK300 coexists amongst other TVWS modems and TV broadcast signals by utilizing vacant channel information provided by a Geo-Location Database through a PAWS (Protocol to Access White-Space Databases) interface. Aviacomm Inc. Page 14
7. Table of Acronyms Full Name Acronym and Abbreviation ADK300 Aviacomm Demonstration Kit 300 CMOS Complementary metal oxide semiconductor CPU Central Processing Unit DDR Double Data Rage DSA Dynamic Spectrum Alliance FCC Federal Communications Commission GHz Giga Hertz LAN Local Area Network LED Light Emitting Diode Mbps Mega-bits per second Mbytes Mega-bytes MHz Mega Hertz NTSC National Television Standards Committee PA Power Amplifier PAL Phase Alternating Line PAWS Protocol to Access White-Space Databases PCB Printed Circuit Board SECAM Sequential color with memory TVWS TV White Space UHF Ultra High Frequency U.FL Micro Low-Profile surface-mount coaxial connector WiFi Trademarked phrase that means IEEE 802.11x WISP Wireless Internet Service Provider Aviacomm Inc. Page 15