Telecommunication: Propagation and Performance ...

Telecommunications RAQIBUL MOSTAFA WIRELESS AND MOBILE C O M M U N I C AT I O N F O R S U S TA I N A B L E R U R A L D E V E L O P M E N T S I S L A M I C U N I V E R S I T Y O F T E C H N O L O G Y, D H A K A

Overview Wireless communications and Bangladesh Wireless propagation channel models ◦ Outdoor and indoor

Enabling technology: Smart antenna system E-learning system design Femtocell (Small cell) for rural broadband connectivity

Wireless communications and Bangladesh

Wireless communications branches Commercial cellular systems Broadcast systems Satellite Navigation Military Astronomy WLAN

Brief History of wireless communications 1895: Guglielmo Marconi

◦ first demonstration of wireless telegraphy (digital!) ◦ long wave transmission, high transmission power necessary (> 200kw)

1907: Commercial transatlantic connections

◦ huge base stations (30 100m high antennas)

1915: Wireless voice transmission New York - San Francisco

1928: Detroit Police Department regular one-way radio communication with its patron cars. 1956: First manually patched 450 MHz service (PTT) 1984: Initial deployment of AMPS system Mid 90s: Deployment of GSM Early 2000: Deployment of 3G/IMT2000 2010 onwards: LTE on the scene IEEE802.xx standards appeared late 90s and continued to evolve 1.11.1

Wireless communications landscape in Bangladesh Cellular Systems WiFi WiMax NTTN Submarine Cable ITC Upcoming Satellite system

National Wireless Network Coverage 1997 3 /64 Districts

2000 30 /64 Districts

2002 50 /64 Districts

2004 61 /64 Districts

At present 64 /64 Districts

7

Future

• MW • STM • NGN • DWDM • MPLS • FTTx

Data

Backhaul/backbone

Voice

• CDMA • GSM • VoIP • Fiber/Coax

• GPRS • EDGE • CDMA 1X • EvDO • WiFi • Wi-MAX • x-DSL • HSPA

• LTE • FTTx

8

Telecom & ICT Applications E Commerce Services Basic Voice Service

Telecom & ICT Enablers E-Education Telemedicine Services

MNOs

Voice Mail Emergency Services

E-mail

FNOs ISPs

E-Governance Services

Internet Access

ICT Drivers

SMS Community Radio

Data Communications

Software Developers Directory Services

Fax Training Centre

Video Conferencing

Research Services Chat Services

Gateway Operators

IP VPN Phone Hiring

PC/Tablet Manufacturers/Resellers Phone/PDA Manufacturers/Resellers CD & CP Electronic Media

Tele-centre services 9

Telecom Indicators

ICT Indicators (as of May‘12)

• Tele-density is more than

62%

62% • Internet Penetration is more 27%

27% • Over 90 M Telecom than

Subscribers

40 M

• More than Internet users.

Tele-Penetration Internet Penetration

10

Telecom Infrastructure & Resources

30,000 BTS

16000 KM Nationwide Optical Fiber

01 Submarine Cable & 06 Terrestrial Cable

7000 Rural Touch Point

14 Community Radios in operation

More than 01 million Human Resources

11

Growth of the Industry 10000000

90 million

Voice Subscriber

90000000 80000000 70000000 60000000 50000000 40000000 30000000 20000000 10000000 0 1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

40 million

45000000

Data Subscriber

40000000 35000000 30000000 25000000 20000000 15000000 10000000 5000000 0 2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

12

Nationwide Communications Activities 3G/4G/LTE licenses issued to country’s 5 major GSM operators NTTN: License provide to 2 operators Ongoing project to provide fiber optic connectivity to all Upazila Project on launching a Communication and Broadcasting satellite to extend connectivity to rural population. 6 ITC licenses for providing redundancy to existing Submarine cable

BTRC have an ILDTS policy which shows the telecom infrastructure of our country.

Social Services/Drivers for Rural Areas

Tele-medicine Improving health quality in Rural

News update & News alerts

e-Agriculture Increase productivity

Cell/SMS broadcasting Alerts on Natural Disaster

e-Banking Bank for unbanked rural communities

e-Education Quality education even in rural

E-Bazaar/Cell Bazaar Buy/Sell from Home No Middle man

Internet & Information service Reduce Digital Divide Better Life

e-Governance Easy access to administration

PCO Communication for everyone & everywhere

14

Fertile Ground for Innovations

Rural people and modern ICTs At a telecentre/CIC taking help from an Infomediaries By a call to helpline Overcoming the barrier of : language illiteracy, ICT illiteracy and information illiteracy Info-lady services at home

 2500 telecentres of Different Models  More than 500 Community Information Center (CIC)-set up by MNOs

Caution! ICT Education a must in rural areas to harvest the benefits of digital age 15

BTRC efforts in promoting connectivity Integrated Infrastructure Development Balanced Telco Growth in Urban & Rural Internet for All Rural Fiber Connectivity Development of Local content Increase Digital literacy

16

Collaboration with ITU ITU Member Since 1973

Actively participation in all ITU sectors

Supporting the role of ITU in guiding World Telecom & ICT Sector to its desired destination

17

ITU Efforts in Rural Communications “Bridging the Standardization Gap: Sustainable Rural Communications” Objectives The main objective of the event is to discuss the strategies, emerging technologies and ICT standards which could be enablers in bringing telecommunications systems and broadband Internet to rural areas in a sustainable fashion. Bangalore, India, 17-18 December 2012, hosted by the Global ICT Standardization Forum for India (GISFI) together with ITU. Participants will discuss the difficult task of increasing access to ICTs in remote areas by providing sustainable incentives for network operators to extend high-cost infrastructures to currently low-revenue markets. How ICT standards might encourage such infrastructure investment will be a key topic of discussion, as will ICT innovations and emerging technologies in this arena. Also of key relevance will be discussions around the need to aid developing countries in the establishment of national standardization secretariats that can help to define a country’s standardization requirements and channel participation in regional and international standardization work.

Wireless propagation channels and measurements

Propagation channel models Propagation mechanisms ◦ ◦ ◦ ◦

Radiation Reflection Scattering Diffraction

Models for predicting received signal strength at a given location ◦ ◦ ◦ ◦ ◦

Outdoor and indoor Large scale and small scale Environment type Scalar and vector Statistical in nature

Outdoor channel models Target systems: ◦ Macrocell, Microcell and Picocell

Environments: ◦ Urban, Suburban and rural

Characteristics: signal reduction with distance with shadowing and multipath fading Prediction models ◦ Large distance based on antenna heights and frequency ◦ Empirical from RF measurements ◦ Okumura/Hata ◦ COST231 ◦ IMT2000

◦ Direct ray-tracing for small distances

Indoor channel models Target systems: ◦ Femtocell (small cells), WLAN, Indoor penetration of cellular signals

Environment ◦ NLOS, rich multipath scattering, low mobility

Models ◦ One Slope Model ◦ Keenan and Motley ◦ Direct ray-tracing with partition/absorption losses

Sample outdoor path loss profile Frequency = 900 MHz ht= 30m, hr=2m Urban area

Sample indoor path loss profile Arbitrary indoor layout Spatial sampling along x-y axes to select measurement points Keenan-Motley used to compute PL at these points Path loss profile

5

75

R6 4

R1

70

R4 80

65 70

3

path loss (dB)

60

R2 2 R7 1

0

60

50

40

R3

30

AP

20 6

R5

55

50

45 40 4

R8

6 4

2

-1

0 y coordinates

-2 -1

2

0

1

2

3

4

5

0 -2

-2

x coordinates

35 30

Smart Antenna Fundamentals •

•

System: •

Antenna array with a digital signal processing capability.

•

Spatial selectivity in both transmission and reception

Algorithms •

Switched beam

•

Adaptive beamforming/nullforming

•

Transmit/Receive diversity

•

Spatial multiplexing

Applications: •

Interference mitigation in cellular networks

•

Radar

•

High throughput system

Smart antenna: Directional beams Active Beam

Conventional antenna ◦ Single element ◦ Omni-directional

Top View

Antenna Array

Smart antenna

Switched Beam System

◦ Multiple antenna elements ◦ Directional beams

Antenna

Desired User

Omnidirectional

Interfering User

Adaptive Array

Antenna Array

Smart Antennas for WLANs Smart Antenna

AP Smart Antenna

Smart Antenna

AP

Interference

Smart Antennas can significantly improve the performance of WLANs* • Higher antenna gain Extend range/ Increase data rate/ Extend battery life • Multipath diversity gain Improve reliability • Interference suppression Improve system capacity and throughput – Supports aggressive frequency re-use for higher spectrum efficiency, robustness in the ISM band (microwave ovens, outdoor lights)

– Data rate increase 802.11n)

M-fold increase in data rate with M Tx and M Rx antennas (MIMO

*Smart Antennas for Wireless Systems by Jack Winters, 2004

WLAN Applications 1

1 Ant 2 Ant, Selective 4 Ant, Selective 4 Ant, Motia RF Beamforming 2 Ant, Motia BB Beamforming 2 Ant, Motia BB Beamforming w/ Ideal Weight 4 Ant, Motia BB Beamforming 4 Ant, Motia BB Beamforming w/ Ideal Weight

50ns Exp Decay Rayleigh Fading*

PER

802.11a/g

0.1

0.01 7

9

11

13

15

17 SNR (dB)

*Smart Antennas for Wireless Systems by Jack Winters, 2004

19

21

23

25

27

Antenna array propagation measurements Narrowband measurements performed in MPRG Lab at Virginia Tech

-5 B ra n c h 1 B ra n c h 2

-1 0

-1 5

2-element array at the handset

Inter-element spacing= 0.1 Small Correlation coefficient= 0.16 Diversity gain at 1% outage= 8 dB

-2 5

dB

RF carrier frequency of 2.05 GHz

-2 0

-3 0

-3 5

-4 0

-4 5

-5 0

-5 5 0

50

100

150

200

250

300

350

400

Wideband Vector Indoor Channel Measurement Wideband vector channel measurement by spanning a BW of 10 MHz RF carrier frequency of 2.05 GHz Fading along distance Frequency non-selectivity observed ◦ Coherence BW about 10 MHz

Outdoor air to ground measurements Wideband measurements done with transmitter in the plane and antenna array receiver on ground Frequency = 2.05 GHz

Elevation angles= 7.50, 150, 22.50 and 300

e-learning: System design for rural population

e-Learning Means to provide education to remote/distant places through available ICT options Global proliferation of broadband connectivity has opened a wide horizon to bring quality education at doorsteps Both developed and developing world benefits from e-Learning ◦ Webinar from IEEE ◦ Extending basic education to remote villages

e-Learning in Bangladesh Potential of e-learning is recognized in academia and ICT sector Application specific to rural areas ◦ To improve literacy rate in rural areas ◦ Mass awareness program ◦ Training in agriculture, healthcare etc.

Content design and delivery ◦ Various agencies involved

ICT infrastructure getting mature to support e-learning in rural areas ◦ 3G connectivity ◦ NTTN at Upazilla level ◦ Innovative initiative to extend connectivity ◦ HSDPA modem to WLAN AP

Test case: e-learning Implementation Need to have a serving Base station in the locality. Mobile needs to have access to internet. Solar panel is the best option to provide power supply in rural areas. Online educational materials need to be arranged. Wi-Fi router is required for distributing access to internet from various classrooms in the school building.

Communication System Design for Implementing elearning Gather a map of the area for e-learning coverage Locate the schools along with the serving BTS/Node B Use propagation channel model to estimate SNR and achievable data rate at the school locations Deploy wireless routers connected to 3G modems to provide coverage to school premise HSDPA selected as the mobile data service to support e-learning system

HSDPA Features Speed: its Peak data rates up to 14 Mbps (at downlink).

Capacity: Capacity Is improved 3 to 4 times from a data perspective when having HSDPA network.

Reduced Delay: Round Trip Time below 100 ms (instead of around 150 ms).

Standardized: HSDPA is standardized in Release 5.

Coverage: Voice, video and data on the same carrier.

HSDPA Fast feedback of channel condition QPSK and 16-QAM Coding from R=1/3 to R=1 Multicode transmission Consecutive slot assignment

HSDPA: Adaptive rate control

Physical Layer Channels HS-DSCH ◦ ◦ ◦ ◦

TTI(transmission time interval) of 2ms (3 slots) 16 QAM SF: 16. Maximum 15 codes per UE(depending on UE capability)

HS-SCCH ◦ ◦ ◦ ◦

Carries information for HS-DSCH demodulation. 3 time slot divided into 2 parts. First slot (first part) carries time critical information Next two slots(second part) contain CRC to check HS-SCCH information & HARQ process information. ◦ Uses SF 128 . ◦ Uses half rate convolution coding

HS-DPCCH ◦ Carries ACK/NACK for physical layer retransmissions. ◦ Carry quality feedback information to be used in the Node B scheduler to determine to which terminal to transmit & at which data rate.

Basic Operations 1. Each UE reports channel quality on HSDPCCH. 2. The node B determines which & when each UE is to be served. 3. Node B informs the UE to be served via HS-SCCH. 4. Serve data to the UE via HS-DSCH. 5. UE sends feedback to Node B on HS-DPCCH.

Data rate estimation CQI to TBS Mapping

SNR to CQI Mapping

CQI

Simulation Flow Chart Distance from User k to Node B Compute outdoor PL from Hata Model

Compute indoor PL from Keenan-Motley Model

TBSn,k RateUserk

Add CCI and slow Fading

Compute SNR at UE

Perform SNR to CQI mapping

n

Total Time

Select TBS from reported CQI

Sample Results -50

40

-100

-150

20

0

0.2

0.4

0.6

0.8

1 TTI

1.2

1.4

1.6

0 2

1.8

4

x 10

CQI Vector

Received Power

Achieved Rate = 1.0563 Mbps

E-learning network setup HSDPA

Performance Enhancements Through smart antenna system at the receiver ◦ Adaptive beamforming ◦ Custom made solution ◦ Slow channel variations ◦ Convergence speed is not a problem

WLAN IEEE802.11n router inside school premises

Antenna Array

Femtocell or Small Cells

• • • •

Miniature home BTS or NodeB. Form-factor close to WiFi Access Points Provide licensed indoor coverage. Excellent HSPA or LTE indoor coverage. Data offload and high speed indoor connectivity prime drivers for this technology.

Rural Femtocell Network Layout

Requirements for rural deployment of Femtocells Site ◦ Very small real estate to place small box-like devices at a moderate height

Power supply ◦ Renewable energy (Solar and battery backup) sufficient to furnish around 100W load

Backhaul ◦ Major issue ◦ Current thoughts on Broadband Satellite or Fiber connectivity

Commercial Femtocells for Rural Deployment Range ~ 2 km Output power 4W 16 simultaneous users Max Data rates: ◦ 14 Mbps (HSDPA) ◦ 5.7 Mbps (HSUPA)

Backhaul ◦ Point to multipoint microwave link ◦ Optical fiber ◦ Satellite

Practical Deployment in Rural Turkey Village: C. Musellim No 3G connectivity Installation on 20m tower in the middle of town Omnidirectional footprint with a range of 2 km Backhaul: ◦ Fiber backbone ◦ Satellite

90% penetration

Conclusions Telecommunications sector growing in the right directions in Bangladesh

Ample opportunities for innovation and growth data connectivity in rural areas Target applications including e-learning can play a major role in uplifting socio-economic status in rural areas Government initiative along with private entrepreneurship is the right mix to bring benefits of modern day communications at rural doorsteps

Acknowledgment BTRC is appreciated for providing relevant data on telecommunications sector