TVWS White Paper Power Automation rev1 - DICTdict.gov.ph/.../uploads/2014/05/tvws-white-paper_power-automation_rev1.pdf · One promising wireless technology is what is known as Dynamic

Copyright 2012 ©by Power Automation 1

Power Automation

A Joint Venture Between Singapore Power and Siemens

WhiteRange Radios: TV White Space for Super-‐WiFi and Beyond

“The world is increasingly interconnected through mobile, high-speed

communications yet two thirds of the world’s population have yet to gain access to the

Internet.” UN Millennium Goals, 2012 Update Report

Executive Summary:

With an impending spectrum crunch, telcos are expected to increasingly look for the

alternate solutions for the more efficient use of spectrum. TV White Spaces (TVWS),

also known as SuperWiFi, refers to unused radio spectrum in TV broadcast bands,

typically at 450-700MHz, which can be used as an alternative wireless platform to

deliver commercial services. The benefits of super Wi-Fi include its ability to travel

over longer distances, penetrate through more obstacles and tough terrain than higher

frequencies, and requiring less power. By using the range and penetration benefits,

coupled with potentially abundant bandwidth, TVWS could offer services that 3G and

Wi-Fi find difficult to offer currently. Power Automation, developed the radios on this

technology, named as WhiteRange. WhiteRange equipments come with 3 different

models, viz. PA TVWS Concentrator Node (used as Access Point), PA TVWS

Gateway Node (used as Gateway) and PA TVWS End Node (used as Station or Client

or remote terminal), depending on the deployment scenario.

Background

For the vast majority of the world’s population, wireless technologies are proving the

most economically efficient way of delivering reliable, affordable broadband access.

But, even within wireless, a mix of solutions will need to be used. For example,

technologies and business models that work well for delivering access to urban

populations might not work well for delivering access to rural or disadvantaged


populations. Moreover, to address growing demand, wireless Internet service

providers are increasingly encouraging consumers to use multiple forms of broadband

access – for example, 3G and Wi-Fi – with the same devices.

What is White Space

One promising wireless technology is what is known as Dynamic Spectrum Access,

which uses location-aware devices and online databases to deliver low-cost broadband

access and other forms of connectivity to consumers. This approach is rooted in the

idea that devices with greater knowledge of their surroundings can opportunistically

use available radio spectrum. There are many TV broadcast channels that are unused

in nearly every location in the world – these empty channels (blocks of spectrum) are

known as “white spaces”, as shown in Figure 1. Dynamic Spectrum Access will first

be used in TV-band White Spaces to deliver popularly known as “SuperWiFi”, which

might be used like existing license-exempt (unlicensed) technologies WiFi.

SuperWiFi will be provided over radio spectrum that is shared among different users

and Internet service providers. This underutilized spectrum is proving to be a key part

of the future of not just universal broadband access but of the solution for the

explosion of devices connecting the Internet.

Figure 1: Concept of White Spaces

The current fixed spectrum allocation scheme results in underutilization of frequency

spectrum. Measurements performed at various locations worldwide showed that the

actual spectrum utilization is only 5% to 15%. This opens the door for possible

utilization of these unoccupied spectrums opportunistically, as illustrated in Figure 2.

Hence, the ability to detect and utilise this at various frequency (freqeuncy hopping)


and using it opportunistically (data slotting) forms the foundation of our invention.

Using it at the TVW channels leads it to be called the TV White Space and becomes

the first in the concept of leveraging on any underutilized spectrum for data and voice

transmission.

Figure 2: Spectrum Allocation vs. Spectrum Utilization

TV White Spaces are the unused TV broadcast channels made available by transitions

from analog to digital TV. In September 2010, the Federal Communications

Commission (FCC) unanimously approved new rules for the use of unlicensed white

space spectrum. The Office of Communication (Ofcom) in UK followed suit one year

later. It has been touted as an untapped resource that has the potential to unleash a

myriad of applications and services, given its attractive propagation characteristics

and relatively large frequency blocks.

Benefits of Super Wi-‐Fi

Super Wi-Fi, or using TV broadcast spectrum for Wi-Fi like connectivity, has several

distinct advantages.


Reduced CAPEX:

• Longer range → Lesser Concentrators

• Able to penetrate walls → Lesser Repeaters

• Variable data rates → Easy deployment in different environments

• Support large number of nodes → Lesser Concentrators

• High data rates up to 54 Mbps → Future proof

• Cable free deployment → Eliminates trenching

Reduced OPEX:

• License Exempt → No recurring costs

• Point-to-Multipoint architecture → Ease of maintenance

Greater Distances: SuperWiFi networks work in much the same way as

conventional WiFi, but the signals travel over longer distances than the typical WiFi

signal. The Free Space Loss for 2.4 GHz and 5.8 GHz is higher because of higher

frequency compared to TVWS band. Figure 3 illustrates the data rate vs. the distance

covered from Access point. Even though the data rate is short, the coverage area by

SuperWiFi (White Spaces) is many times longer. In typical applications, a strong Wi-

Fi signal can cover 100 meters while a Super Wi-Fi signal at the same power level can

easily travel 400 meters and with higher power can cover many kilometers. Four

times the distance will lead to 16 times the area covered. With the same power

comparing 2.4 GHz to 600 MHz. The result is more bandwidth, lower network costs

and lower power consumption.


Figure 3: Comparison of data rates with range by WiFi & SuperWiFi

Moreover, the 2.4 GHz has only three non-overlapping channels and numerous

devices working on these channels, is more prone to interference which leads to drop

in the data throughput tremendously. 5.8 GHz ISM band has more channels, but the

free space loss is too high and the range covered is too short.

Penetrates Common Obstructions: Conventional WiFi is relatively weak

when it comes to working in typical physical settings, bumping up against concrete

obstructions and many types of walls. Most population centers have thousands of

likely WiFi impediments and almost any installation in a building with more than a

few rooms will eventually hit limits. Likewise, many rural areas are difficult to serve

using existing technologies due to heavy foliage or topographical challenges. Super

WiFi can overcome these limits, as shown in Figure 4.


Source: Microsoft website Figure 4: SuperWiFi signal penetrate through walls

Greater Efficiencies: Covering a longer and wider range with approximately the

same power and computing requirements results in systems that will deliver more

bandwidth and more consumer benefits at lower network costs and lower power

consumption. In addition, consumers will be able to satisfy their ever increasing

bandwidth appetites and Internet providers will be able to provide more throughputs

in more places to more consumers.

Technical Features of WhiteRange

• WhiteRange device works with Geo-location database and optionally

Spectrum Sensing. It detects the available channel and guides TV White Space

on the Concentrator to transmit in that channel.

• Configurable Network Topology: The signal may be transmitted using a

highly directional antenna or omni-directional antenna depending on

application and scenario. The device is configurable for Point-to-Point, Point-

to-Multipoint, Access Point, terminal or gateway.

• Secured data communication with meter authentication and data encryption.

• Geolocation data base & Spectrum sensing as optional features.


Figure 5: TVWS Radio

• One of the best Radio Specifications in industry:

Parameters Specification Frequency Range 630-‐750 MHz Max. P1dB +31 dBm Channel Bandwidth 20/ 10/ 5 MHz Receiver sensitivity -‐96 dBm Data Rate Adaptive from 250 kbps to 54 Mbps Modulation BPSK, QPSK & 16 QAM Channel Setting Any channel 5 to 20 MHz at the step

of 2/3 MHz System Gain (without antenna) 128 dB RF Interface N(F) Connector Power Rating 24V Form Factor 25X25X8 cm Operating Temperature -‐30 to +55C Operating Humidity Up to 95% non-‐condensing

How the technology works

The most common implementation of SuperWiFi networks will be accessed using

smart, radio-enabled Geolocation Database. Devices determine their location and

query a “geolocation” database. The database will tell the device which TV white

spaces channels, and at what power level, it is permitted to operate on in its current

location. The database has a list of all protected TV stations and frequencies across

the country, so the devices can avoid causing interference to TV broadcasts and

wireless microphone signals. Alternatively, through dynamic sensing, our system

adopts a real time scanning feature that is on top of the geolocation database, this

allows TVWS to be implemented anywhere at any frequency band as long as the

antenna frequency range is supported. This technology is truly dynamic as different


TV channels or frequency band become available, as SuperWiFi devices can

opportunistically switch from one group of channels to another. This win-win

translates to greater network capacity, allowing a greater number of users in a given

area while, at the same time, protecting television reception from interference. All of

this engineering will be invisible to the consumer, who will simply experience more

ubiquitous broadband connectivity. The steps of operation are shown in Figure 6.

Source: Microsoft website

Figure 6: SuperWiFi Access Safeguards Incumbents from Interference

Progress to Date

The U.S. FCC has already adopted regulations allowing non-exclusive license-exempt

access to the TV White Spaces. A full scale deployment trial in Cambridge, UK (in

April 2012) was completed with results that exceeded expectations and the UK

regulator, Ofcom, is using these results to inform regulatory proceedings. Other

regulators, in addition to the FCC in the US and Ofcom in the UK, have begun to

implement the changes necessary to enable commercialization of this approach.

Cognitive Radio Venues (CRAVE) trials launched in March 2011 to explore technical

aspects and business models, to inform the development of a regulatory framework

for TVWS usage in Singapore. The Singapore White Spaces Pilot Group (SWSPG)

was established in April 2012 with support from Infocomm Development Authority

(IDA), the Regulator of Singapore. The objective of the pilot group is to promote the

Lion City as a leading test-bed and innovative zone for conducting pilot projects using


White Spaces technologies, thereby accelerating the adoption of White Spaces

technologies locally, regionally and eventually globally. SWSPG aims to attract broad

members from public and private sectors, local and international industry participants,

academic and research institutes and end-user organizations that could benefit from

this next generation broadband wireless connectivity. With all this, it is only a matter

of time before both the heavy bandwidth users in developed markets and those yet to

even be connected in the furthest corners of the world to benefit from the innovative

use of Super Wi-Fi.

Source: Singapore White Space Pilot Group Figure 7: Worldwide Trials & Demos

Applications of WhiteRange

Other applications of WhiteRange include:

• Private wireless point-to-multipoint network

Metro area SuperWiFi hotspots: There is an opportunity for existing or new service

providers to create wide-are hotspots for consumers of mobile broadband data. A

private point to multi-point wireless network can be established at lower cost for the

smart city application, for public utilities, lift monitoring, flood monitoring, or traffic

monitoring.


• Point-to-point cable replacement for Internet

The potential business models and services:

Cellular Offload network: Cellular service providers could setup White Spaces access

points on some of their existing towers to offload mobile data access onto this parallel

network. This will be cheap (unlicensed) spectrum to alleviate their severe spectrum

crunch with the advent of smart phones.

For enhanced WiFi to provide rural connectivity. It is more economical. Poles with

SuperWiFi access points can be setup in rural areas and connected to the internet

using a wired backhaul or to one another in a mesh topology to one large internet pipe

eliminating the need for trenching.


• SmartGrid Applications

The traditional power grid is grossly inefficient and unable to foster the energy

savings needed to confront the global warming threat. Adding IT to the grid makes it

possible to better direct the electricity flows toward where they are needed, integrate

non-constant energy sources more effectively (renewable energies in particular) and

reduce electric consumption without harming life standards.

By controlling the activity of constantly running appliances during peak/off peak

hours, utility companies could create significant nationwide energy savings. For

example, the hot water boiler of the house would heat the water needed for the

morning shower during the hours of the night when demand is low that electricity

generated during this time goes to waste. This approach would decrease morning peak

electricity consumption and prevent the need to fire up additional costly and polluting

fuel power plants.

White Spaces could be used to transfer the information needed to ensure the smooth

functioning of such smart grid applications. Specifically, it delivers real-time


broadband connectivity to remote substations and switchgear, requests mission critical

data from substations, manages power flow and protects the system and employees

while maintaining the local grid. By putting the TVWS devices into some of the

meters, it can be easily deployed to enable broadband connectivity to any building or

homes. The following diagram illustrates by enabling 3 meters as gateway with

TVWS and secondary broadband PLC or Zigbee device, the whole building can be

connected for many low data volume device like electricity, water and gas meters or

simply sensors with Zigbee/PLC communications using the same high speed M2M

network. Our latest development is putting a WIFI chip in each of these gateway

meters or as a standalone module to make a localised WIFI hotspot

=

TVWS with WIFI to UHF convertor located inside a meter or as module box


• Maritime Network

Another potential application has been identified to have a better coverage of network

in the sea for a longer range. It is possible to achieve up to 6 km range in the sea using

SuperWiFi. This allows all ships at port to have internet and connectivity easily which

traditionally relies on near port 3G or expensive satellite communications.

• Cellular Repeater

Mobile White Spaces services could allow for a mobile service that does not rely on

licensed spectrum, hence significantly reducing implementation costs. In addition,

such unlicensed spectrum provides significantly additional bandwidth to the existing

national cellular infrastructure, which is facing the spectrum crunch. Use of

unlicensed spectrum for mobility could provide opportunities to niche and local

mobile players who cannot afford to bid for licensed spectrum. The wide-band

properties of the White Spaces spectrum could also potentially provide other unique

technological opportunities, allowing mobile provides to craft a service that takes

advantage of properties of different portions of the radio spectrum by creating a

communications link constructed from disparate channels. This can also be used to

offload 3G networks traffic which are increasingly congested due to the use of

mobile internet phones and devices.


References

1. White spaces (radio) - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/White_spaces_%28radio%29

2. Spectrum Survey in Singapore: Occupancy Measurements and Analyses http://www.pwtc.eee.ntu.edu.sg/News/Documents/Spectrum%20survey%20in%20Singapore_%20Occupancy%20measurements%20and%20analyses.pdf

3. Implementing geolocation: - Stakeholders - Ofcom http://stakeholders.ofcom.org.uk/binaries/consultations/geolocation/summary/geolocation.pdf

4. TV White-Space Device Prototype Using Covariance-Based Signal Detection http://cms.comsoc.org/SiteGen/Uploads/Public/Docs_DYSPAN_2008/I2R_Demo_IEEEDySPAN2008.pdf 5. Distributed Spectrum Sensing for Cognitive Radio Networks with Heterogeneous Traffic (Invited Paper) http://www.sutd.edu.sg/faculty/yuenc/publications/Isabel2010.pdf 6. Trial of White Space Technology accessing VHF and UHF band in Singapore http://www.ida.gov.sg/doc/Policies%20and%20Regulation/Policies_and_Regulation_Level2/WST/WhiteSpaceTP.pdf 7. Super WiFi Technology white paper by Microsoft download.microsoft.com/.../SuperWiFi%20Overview.pdf 8. Super Wi-Fi likely to see success first in Asia http://www.zdnet.com/super-wi-fi-

likely-to-see-success-first-in-asia-7000007250/

9. 'Super Wi-Fi': Super, But Not Wi-Fi http://www.pcmag.com/article2/0,2817,2399447,00.asp


Author: Kerk See Gim

Email: [email protected]/[email protected]

Tel: +65 9687 4908

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