Indian Journal of Radio & Space Physics

 

Total visitors: 588 since 22-05-07

(CODEN : IJRSAK        ISSN : 0367-8393)

VOLUME 36

NUMBER 3

JUNE 2007

 

CONTENTS

 

Guest Editorial: Rural radio communication – The Indian perspective

        Ashok Jhunjhunwala*

 

163

 

Special Supplement

 

Next generation wireless for rural areas

        Ashok Jhunjhunwala*

 

165

 

 

Broadband wireless technology for rural India

        Bhaskar Ramamurthi*

 

168

 

Can 3G technologies benefit rural India?

        G Venkatesh* & Ashwin Ramachandra

 

172

 

IEEE 802.16e (Mobile-WiMAX) for rural deployment

      A Paulraj*

 

178

 

Cost-effective mobile communications for developing economies

        Joseph Shapira*

 

182

Rural connectivity in India: The n-Logue example

        Sangamitra Ramachander*

 

188

 

Rural radio communications: Services and applications

        Sridhar Iyer*

 

192

Regular Papers

 

Trace gases behaviour in sensitive areas of the northwestern Himalaya – A case study of Kullu-Manali tourist complex, India

        Jagdish C Kuniyal*, P S P Rao, G A Momin, P D Safai, S Tiwari & K Ali

 

 

197

Mathematical modelling of katabatic winds over Schirmacher region, East Antarctica

        Ashok Kumar*, V B Gupta, H N Dutta & Sachin D Ghude

 

204

Bowen ratio estimation of surface energy fluxes in a humid tropical agricultural site,
Ile-Ife, Nigeria

        O R Oladosu*, O O Jegede, L A Sunmonu & A T Adediji

 

 

213

Directional reflectance of vegetation targets: Simulation of its space measurements by coupling atmospheric and biophysical radiative transfer models

        M R Pandya*, R P Singh & S Panigrahy

 

 

219

Effect of microwave radiation on the electrical parameters of soil

        O P N Calla*, Dinesh Bohra, Sanjeev Kumar Mishra, M Alam, D Hazarika &
L Ramawat

 

229

___________________

*Authors for correspondence

 

 


Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 165-167

 

Next generation wireless for rural areas

Ashok Jhunjhunwala

Department of Electrical Engineering, Indian Institute of Technology, Chennai 600 036

ashok @tenet. res. in

Received 26 March 2007; accepted 4 April 2007

Following a spectacular growth of telecommunication in India, the country is focusing on the technology to provide broadband connections to its rural areas. Broadband wireless technologies are emerging to enable this to happen. Four such technological efforts are on the horizon. The paper looks at the four initiatives and what they could deliver to Indian rural areas in the next few years.

Keywords: Wireless communication, Broadband corDECT, IEEE 802.16 m, 3GPP–LTE, 3GPP2–UMB

PACS No: 84.40.Ua

 

 

 

Indian Journal of Radio Space Physics

Vol. 36, June, 2007, pp. 168-171

 

 

Broadband wireless technology for rural India

Bhaskar Ramamurthi

Department of Electrical Engineering, TeNeT Group, Indian Institute of Technology, Chennai 600 036, India

bhaskar@tenet.res.in

Received 27 September 2006; accepted 27 February 2007

Broadband services can be best provided in rural India using wireless technology. Given modest income levels, internet-based services are accessible to most of the rural populace only through a kiosk model of delivery. Such services call for a wireless system that can provide at least 256 kbps in a sustained manner, to each of around 200 villages within a radius of 20 km from an Internet POP (Post Office Protocol). The challenge, however, is to do this at a cost per connection of under US$ 250 for the wireless equipment, in order to make the kiosk a viable business. Emerging wide-area broadband wireless technologies such as those based on the IEEE 802.16 (WiMAX) standard, when mature, may meet these performance and cost requirements. If broadband services are to be provided today, and at an affordable cost, one has to look for innovative ways of adapting low-cost, high bit-rate, and high-capacity technologies meant for local networks. Two standards that are amenable to such adaptation are DECT and IEEE 802.11 (WiFi), and Broadband corDECT and WiFiRe systems are, respectively, examples thereof. The corDECT system has been proven in rural deployments and shown to provide a feasible solution.

Keywords: Broadband service, Wireless technology, Mobile telephone, Rural wireless communication

PACS No: 84.40.Ua

 

 

 

 

 

 

 

 

 

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 172-177

 

 

Can 3G technologies benefit rural India?

G Venkatesh & Ashwin Ramachandra

Sasken Communication Technologies Limited, 139/25, Domlur, Bangalore 560 075, India

gv@sasken.com, ashwinr@sasken.com

Received 27 September 2006; accepted 27 February 2007

To increase telecom penetration into rural India, we would need low cost options for networks and devices that provide support not only for voice services, but also for rich media and higher data rate services. In this paper, the authors examine whether the evolution of GSM (Global System for Mobile communication) into 3G and HSDPA (High-Speed Downlink Packet Access) could enable this transformation, since this provides higher peak data rates and also significantly increases the network capacity. The problem is that 3G devices and services are typically part of the premium (high-price) services in the developed countries, while they have to be offered at very affordable prices if they have to take off in the rural areas. A paradigm shift may thus be required to resolve this paradox. In this paper, the authors examine if low cost 3G and HSDPA is really feasible.

Keyword: 3G technology, HSDPA, GSM

PACS No: 84.40.Ua

 

 

 

Indian Journal of Radio Space Physics

Vol. 36, June, 2007, pp. 178-181

 

 

 

IEEE 802.16e (Mobile-WiMAX) for rural deployment

A Paulraj

Information Systems Laboratory (ISL), Stanford University, 272 David Packard Electrical Engineering Building
350 Serra Mall, Stanford, CA 94305-9510, USA

and

Beceem Communications Inc, 3960 Freedom Circle, First Floor, Santa Clara, CA 95054, USA

Received 27 September 2006; accepted 27 February 2007

The IEEE 802.16e (or simply 16e) is an emerging global standard targeted for broadband services to mobile/nomadic users within urban areas with macro cellular type deployment. Other applications of 16e can be micro cell indoors and outdoors serving hotspots and enterprises. The 16e promises wideband operation with high spectral efficiency. Net throughputs up to net 70 mbps peak and 20 mbps average are possible in 10 MHz channels. The 16e standard for urban mobile applications is expected to be ratified in Sep. 2005. The WIMAX forum has approved two profiles wave 1 and 2. The former is entering Korean deployment in mid 2006. Wave 2 profiles address more advanced features will begin trials in late 2006. Clearly, 16e is a very flexible standard capable of multiple applications. In this paper the author argues that the flexibility in 16e also makes it suitable for efficiently supporting rural applications also. Requirements for rural deployment and a possible rural profile for 16e are discussed. Also it is shown that it can be configured to offer attractive performance and cost advantages.

Keywords: Broadband service, Mobile-WiMAX, Rural broadband application

PACS No: 84.40.Ua

 

 

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 182-187

 

Cost-effective mobile communications for developing economies

Joseph Shapira

Department of Electrical Engineering, Indian Institute of Technology, Chennai 600 036, India

and

Comm & Sens Ltd., 23 Sweden Street, Haifa, Israel

E-Mail: jshapira@comm-and-sens.com

Received 27 September 2006; accepted 27 February 2007

Optimization of the radio access is a major challenge for a mobile wireless communications system, where both the channel and the multitude of users are not known exactly. The classical cellular architecture provides only rough guidelines, and at the same time, propagation modeling, statistics, and network simulations, fall short of representing and optimizing the actual network performance. Cost-aware Wireless Access Optimization (WAO) governs the radio coverage at the base stations and additional RF access points (repeaters) as required by the environment and traffic demands. Optimal performance is achieved by combining prediction models with dynamic measurements, and applying coverage and diversity means accordingly. The optimization of the new data-optimized systems – 1×EV-DO and HSDPA do not follow the same pattern, and a completely different optimization paradigm has to be taken when mixed services operate on the same network. These techniques and the corresponding benefits experienced in practical deployments are reviewed. Major savings in infrastructure costs have been shown, both in rural and in congested urban areas. The developing economies may take the leading role in developing WAO, due to their cost-awareness, fast development of networks, and the keen interest to enhance the domestic value of the systems and the service.

Keywords: Mobile communications, HSDPA, UMTS, CDMA

PACS No.: 84.40.va

 

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 188-191

 

 

 

Rural connectivity in India: The n-Logue example

Sangamitra Ramachander

TeNet Group, Indian Institute of Technology, Chennai 600 036, India

Received 27 September 2006; accepted 27 February 2007

This paper mainly aims to explain about the telecom boom in India and throws light on the technologies of today and tomorrow. It briefly discusses about, how technologies are now starting to be available to connect every village and also it details challenges faced by the technologies in rural areas. With these in mind a total innovative business model was required to deliver Internet services to rural areas. In order to meet this need a company called n-Logue was incubated to significantly enhance the quality of life of every rural Indian by setting up a network of wirelessly connected internet kiosks in villages throughout India. The challenges from technology point of view are many. The systems that provide connectivity need to be relatively inexpensive if they are to be commercially deployed, given the lower incomes in rural areas compared to urban areas. This paper concludes by saying that with the help of drastic developments in technology sector, providing connectivity in rural areas is entirely possible today.

Keywords: Rural connectivity, Teledensity, ICT, n-Logue communication

PACS No.: 84.40.ua

 

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 192-193

 

Rural radio communications: Services and applications

 

Sridhar Iyer

KR School of Information Technology, Indian Institute of Technology, POWAI, Mumbai 400 076, India

Received 27 September 2006; accepted 27 February 2007

The internet has enormous power to transform rural communities. Internet based services can mitigate the gap between urban and rural areas in terms of access to various services, such as health-care, domain consultancy and education. It can also provide new avenues of income generation to rural areas. This paper gives an overview of some existing internet based services and applications for rural India and presents a case study of one application in Education.

Keywords: Rural radio communications, OSCAR, E-governance, E-healthcare, E-portals, E-agriculture, aAqua, eChoupal

PACS No: 84.40.Ua

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 197-203

 

 

Trace gases behaviour in sensitive areas of the northwestern Himalaya–A case study of Kullu-Manali tourist complex, India

Jagdish C Kuniyal

G B Pant Institute of Himalayan Environment and Development, Himachal Unit, Mohal-Kullu (HP) 175 126, India

e-mails: kuniyaljc@yahoo.com/jckuniyal@rediffmail.com

and

P S P Rao, G A Momin, P D Safai, S Tiwari & K Ali

Indian Institute of Tropical Meteorology, Dr Homi Bhabha Road, Pashan, Pune 411 008, India

Received 14 July 2005; revised 28 February 2007; accepted 23 March 2007

Surface concentration of the three important trace gases, ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2) were measured at three different tourist locations, namely Kullu, Manali and Kothi in the northwestern Himalayan region, which are located at 1220 m, 2050 m and 2530 m above the mean sea level mainly to asses the anthropogenic impact. The surface O3 was monitored for four years during the period 1998 - 2002 and 2004 at the time of peak tourist season (May-June), and SO2 and NO2 were measured during the entire period in 2003. The peak O3 concentrations reached close to 50 ppb level, while the annual mean concentrations of O3, SO2 and NO2 remained within the United States Environmental Protection Agency’s (USEPA’s) National Ambient Air Quality Standards (NAAQS). The peak hourly average values of O3 was 44 ppb at Manali and 32 ppb at Kothi during evening (1700 hrs IST), while that at Mohal (near Kullu) was 32 ppb in the afternoon (1500 hrs IST) period. The seasonally average value of maximum concentration of NO2 was 3.8±0.6 mg m-3 at Kothi and 7.6±1.0 mg m-3 at Mohal in autumn (October-November), while that of SO2 was 21.4±1.8 mg m-3 at Kothi and 18.8±1.3 mg m-3 at Mohal during the monsoon (July-September) and summer (April-June) periods, respectively. Vehicular emissions and biomass burning for heating and cooking during the winter period (especially when power failure is common) as well as during forest fires could be the major contributors for increased emissions of these trace gases. However, the influence of long-range transport may also be important.

Keywords: Surface ozone, Nitrogen dioxide, Sulphur dioxide, Kullu-Manali, Northwestern Himalaya

PACS No.: 92.60.Mt; 92.60 Sz; 92.70 Cp

IPC Code : G01 J15/06; G01 W1/17

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 204-212

Mathematical modelling of katabatic winds over Schirmacher region, East Antarctica

 

Ashok Kumar & V B Gupta

School of Future Studies and Planning, Devi Ahilya University, Indore 452 017

E-mail: ashok_kumarg@yahoo.com

and

H N Dutta

Radio and Atmospheric Sciences Division, National Physical Laboratory, Dr. K S Krishnan Road, New Delhi 110 012

E-mail: hndutta@mail.nplindia.ernet.in

and

Sachin D Ghude

Indian Institute of Tropical Meteorology, Pune 411 008

Received 25 October 2005; revised 25 September 2006; accepted 15 February 2007

A one-dimensional mathematical model for flow of katabatic winds over Schirmacher region of East Antarctica has been developed. The model is based on momentum and sensible heat transport to the ice slope surface under calm conditions. A relationship of potential air temperature with the height and elevation of the reference state is suggested and used in the model. The model parameters were estimated using the measurements of surface based meteorological parameters and high resolution maps of pressure contours. The wind velocities have been computed using the model on actual terrain slope around 130° in which direction maximum katabatic flow moves towards the periphery of the continent , the ratio of mean bulk coefficients (CH/CM) and over large variations in slope angle (a), potential temperature difference between air parcel and slope surface (q), and slope length (l). The results suggest that the inclination angle or terrain slope and the distance at which inversion forms, control the speed of katabatic winds. At the same time, the direction of katabatic wind is controlled by the slope of the icy terrain.

Keywords: East Antarctica, Katabatic winds, Cold air parcel, Sensible heat, Ice surface, Schirmacher region

PACS No.: 92.60. Gn

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 213-218

Bowen ratio estimation of surface energy fluxes in a humid tropical
agricultural site, Ile-Ife, Nigeria

 

O R Oladosu1, O O Jegede2, L A Sunmonu2 & A T Adediji1

1Department of Physics, Federal University of Technology, P. M. B. 704, Akure, Nigeria

2Department of Physics, Obafemi Awolowo University, Ile-Ife, Nigeria

Email: koladosu@yahoo.com

Received 2 May 2006; revised 31 August 2006; accepted 28 March 2007

 

The Bowen ratio energy balance (BREB) is a micrometeorological technique often used for estimating the surface energy fluxes (i.e. latent heat, sensible heat fluxes) because of its simplicity, robustness, and affordability. The same method has been applied in this study to partition the available energy (Rn G+) at a humid tropical agricultural site in Ile-Ife, Nigeria (7o33'N, 4o33'E) during the transition period (wet and dry) between 25 and 29 Feb. 2004. Results obtained for the diurnal variations of the energy fluxes in relation to changing surface condition are satisfactory. For the relatively dry days, the sensible heat flux is comparatively of the same magnitude as the latent heat flux except on a day when it was a little higher, but it is less during the wet days. It is therefore obvious from this study that for a tropical weather, evaporation is the next essential factor after radiation in the energy balance due to the prevailing humid conditions in the zone.

Keywords: Bowen-ratio, Surface energy balance, Humid tropics, Ile-Ife, Nigeria

PACS No.: 92.60.Ry

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 219-228

 

 

Directional reflectance of vegetation targets: Simulation of its space measurements by coupling atmospheric and biophysical radiative transfer models

 

M R Pandya, R P Singh & S Panigrahy

Agriculture Forestry and Environment Group, Space Applications Centre, ISRO, Ahmedabad 380 015, Gujarat, India

E Mail: mrpandya@sac.isro.gov.in

Received 3 August 2006; accepted 7 March 2007

Vegetative surfaces are non-lambertian and deriving their spectral properties from space-borne sensors becomes complicated when off-nadir view angles are taken into consideration. In order to utilize off-nadir observations a complete understanding of directional reflectance is needed. This requires understanding of propagation of solar radiation as radiative transfer (RT) problem through a coupled system of vegetation canopy and atmosphere as a function of view angles. In this paper, a new approach of coupling biophysical (PROSAIL) and atmospheric (6S-code) RT models has been proposed to simulate at-sensor directional reflectance for vegetation target. At-sensor reflectance was simulated using 6S-code for the viewing geometry pertaining to 0, 5 and 26 deg view angles (hypothetical multispectral sensor with forward and backward viewing capabilities) for varying atmospheric conditions with the lower boundary condition parameterized through vegetation canopy reflectance obtained from PROSAIL model. Sensitivity of directional reflectance to input parameters were inferred at top-of-canopy and top-of-atmosphere level. The degree of anisotropy in reflectance pattern due to directional viewing represented by a parameter called g-factor was quantified (3-24% in red, 2-9% in near-infrared and panchromatic channels at top-of-atmosphere) which depends on wavelength and increases with atmospheric turbidity. This modeling study would help understanding capabilities of future space-borne sensors with directional/multi-spectral imaging.

Keywords: Directional reflectance, Non-lambertian surface, Biophysical radiative transfer, Atmospheric radiative transfer, Indian remote sensing (IRS) satellite

PACS No: 68.49. h; 78.40. q

 

 

Indian Journal of Radio & Space Physics

Vol. 36, June 2007, pp. 229-233

 

 

Effect of microwave radiation on the electrical parameters of soil

 

O P N Calla, Dinesh Bohra & Sanjeev Kumar Mishra

International Centre For Radio Science, “OM NIWAS” A-23, Shastri Nagar, Jodhpur 342 003, India

and

M Alam, D Hazarika & L Ramawat

Department of Electronics and Telecommunication, Assam Engineering College, Jalukbari, Guwahati 781 013, India

Received 24 August 2005; revised 19 October 2006; accepted 12 December 2006

The paper presents the study of the effect of microwave radiation on dry soil. For this, five different soil samples were collected from various geographical regions of India. The waveguide cell method was employed for the determination of the storage factor (e¢) and the loss factor (e²) of the soils. In this paper the methodology of measurement of dielectric constant for unexposed and exposed soils to microwave radiation is given and the results obtained are discussed.

Keywords: Electrical parameter, Soil texture, Microwave radiation, Dielectric constant

PACS No: 95.75 Rs; 84.40 Xb

IPC Code: G 01 N33/24