scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Wireless in Local Loop—Some Fundamentals

01 Nov 2000-Iete Journal of Research (Taylor & Francis)-Vol. 46, Iss: 6, pp 421-433
TL;DR: The paper concludes with a discussion on the emerging third generation (3G) wireless standards, and the new technologies which are being introduced into the network, and what will be their impact on Internet and Multimedia bit-rates and services.
Abstract: The enhancements in Internet technology and mobile access technology over the last decade, can be leveraged effectively to build Wireless in Local Loop (WiLL) systems, which can enable rapid expansion of telecom and Internet access in developing countries. However, the design of a WiLL system requires one to understand some fundamentals concerning the Access Network and its connectivity to backbone network as well as the traffic requirement for a voice and Internet connection. The requirements of WiLL, in contrast to that of a Mobile cellular system need to be clearly understood. Equally important is the concern for capacity and spectral efficiency, especially as higher bit-rate Internet systems become a must for developing countries to get a fair share of the economic advantages that telecom technologies provide. This paper looks at these fundamental issues in context of GSM, IS-95 and DECT Technologies. This paper further takes a brief look at some recent technological developments, which are likely to ...
Citations
More filters
Proceedings Article
01 Jan 1991
TL;DR: It is concluded that properly augmented and power-controlled multiple-cell CDMA (code division multiple access) promises a quantum increase in current cellular capacity.
Abstract: It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

2,951 citations

Journal Article
TL;DR: In this article, the authors have shown that feedback from customers should be part of delivery cycle in order to enable better and efficient delivery of services to desired audience, which is supported by both literature of field experience.
Abstract: India is a country with more than half the population depending on agriculture for their livelihood but manages only 14 % contribution in its GDP. The country has fragmented land holdings, which has given rise to considerable amount of independent farmers with a near stagnant productivity. In spite of initiatives by Government of India both at the center and at state levels, there continues a gap between land and lab. Karnataka is no exception with more than 80 % of total land holdings under small and marginal farmers. The Government of Karnataka, with the aim of providing this sect of farmers the latest crop related and information using ICT tools, has launched a service to relay agricultural advisories by means of a ‘PUSH’ voice-message to farmers in five delta districts. These services will be used to record feedback and assist farmers on various fronts including weather updates, agriculture equipment’s etc. This research paper enlightens ways and methods of delivery of services and improves its efficiency of prevalent services. ICT plays a transformative role and potential, which is supported by both literature of field experience. It empowers farmers to convey proper and real time feedback in accordance with proper guidance on their agricultural needs. The results indicate that feedback from customers should be part of delivery cycle in order to enable better and efficient delivery of services to desired audience.

5 citations

Proceedings ArticleDOI
01 Nov 2005
TL;DR: This paper discusses the approach in the form of a framework called Empowering Communities through KnOwledge (ECKO), which enables knowledge sharing among the community and fosters the creation of multi-dimensional knowledge repositories.
Abstract: In an era of information propagation through various medias like Internet, there are many parts of the world, which are untouched by this wave. This kind of gap, known as 'digital divide' exists even within a country and even among developed nations. A solution to this problem of bridging the digital divide requires a platform for consuming, sharing, and producing information in an easy-to-use and understandable format, apart from the infrastructural requirements. This paper discusses our approach in the form of a framework called Empowering Communities through KnOwledge (ECKO). Our framework includes the processes, and deployment models apart from the software. The framework enables knowledge sharing among the community and fosters the creation of multi-dimensional knowledge repositories. We illustrate our phase-by-phase approach, which is generic enough to be replicated across countries. The feedback obtained from the stakeholders, and the effort requirements are also discussed.

4 citations


Cites methods from "Wireless in Local Loop—Some Fundame..."

  • ...We chose a pilot location Melur, in the southern state of India that used an innovative technology called CorDECT-WLL [19] for connectivity....

    [...]

Journal ArticleDOI
TL;DR: The role that Indian and Chinese telecom companies have played towards this reduction of per-line CAPEX is discussed and technologies still dominated by the West are identified.
Abstract: After decades of very modest growth, telecom in India has taken off. While liberalisation of telecom sector created the conditions, the key to this take off has been a conscious effort in India to drive down the capital expenditure (CAPEX) of telecom infrastructure which made telecom affordable to large sections of Indian people. This paper discusses the role that Indian and Chinese telecom companies have played towards this reduction of per-line CAPEX and identifies technologies still dominated by the West. Telecom is now set to grow rapidly and India would achieve 200 million connections in less than a decade. However, this optimist situation is still, pretty much confined to urban areas. It is the growth of telecom and Internet infrastructure in rural areas, that have much greater potential. But harnessing of this potential requires special efforts. This paper presents a glimpse of how this could be made possible.

3 citations


Cites background from "Wireless in Local Loop—Some Fundame..."

  • ...The driver behind this has been low cost innovative CorDECT technology [27], developed at liT Madras and Midas Communications [28] at Chennai....

    [...]

Book ChapterDOI
01 Jan 2013
TL;DR: In this article, the authors discuss some attempts over the last decade in using Information and Communication Technology (ICT) to empower rural communities and those who are socially and economically left behind in India.
Abstract: This chapter discusses some attempts over the last decade in using Information and Communication Technology (ICT) to empower rural communities and those who are socially and economically left behind in India. It begins with discussing the drivers of telecommunication growth in India since the mid-nineties. Then, it addresses the role of the village Internet kiosks in bringing the Internet to remote villages and articulates on the challenges facing the kiosk model. It then touches upon the rapid growth of mobile telephony in rural India. Following this, it discusses a number of attempts that use mobile telephony to empower rural communities. The authors also use multiple case studies to explore the role of ICT in supporting agriculture, delivering healthcare, achieving financial inclusion and improving the overall livelihood of rural communities in India. The key lessons learned include that the “one-size fits all” model does not work for all communities. In addition, involving both local and federal governments is crucial for the success of community-focused initiatives. Moreover, engaging communities and educating them about the benefits of delivered services would help in sustaining such community-focused initiatives.

3 citations

References
More filters
Book
15 Jan 1996
TL;DR: WireWireless Communications: Principles and Practice, Second Edition is the definitive modern text for wireless communications technology and system design as discussed by the authors, which covers the fundamental issues impacting all wireless networks and reviews virtually every important new wireless standard and technological development, offering especially comprehensive coverage of the 3G systems and wireless local area networks (WLANs).
Abstract: From the Publisher: The indispensable guide to wireless communications—now fully revised and updated! Wireless Communications: Principles and Practice, Second Edition is the definitive modern text for wireless communications technology and system design. Building on his classic first edition, Theodore S. Rappaport covers the fundamental issues impacting all wireless networks and reviews virtually every important new wireless standard and technological development, offering especially comprehensive coverage of the 3G systems and wireless local area networks (WLANs) that will transform communications in the coming years. Rappaport illustrates each key concept with practical examples, thoroughly explained and solved step by step. Coverage includes: An overview of key wireless technologies: voice, data, cordless, paging, fixed and mobile broadband wireless systems, and beyond Wireless system design fundamentals: channel assignment, handoffs, trunking efficiency, interference, frequency reuse, capacity planning, large-scale fading, and more Path loss, small-scale fading, multipath, reflection, diffraction, scattering, shadowing, spatial-temporal channel modeling, and microcell/indoor propagation Modulation, equalization, diversity, channel coding, and speech coding New wireless LAN technologies: IEEE 802.11a/b, HIPERLAN, BRAN, and other alternatives New 3G air interface standards, including W-CDMA, cdma2000, GPRS, UMTS, and EDGE Bluetooth wearable computers, fixed wireless and Local Multipoint Distribution Service (LMDS), and other advanced technologies Updated glossary of abbreviations and acronyms, and a thorolist of references Dozens of new examples and end-of-chapter problems Whether you're a communications/network professional, manager, researcher, or student, Wireless Communications: Principles and Practice, Second Edition gives you an in-depth understanding of the state of the art in wireless technology—today's and tomorrow's.

17,102 citations

Journal ArticleDOI
TL;DR: In this article, the authors examined the performance of using multi-element array (MEA) technology to improve the bit-rate of digital wireless communications and showed that with high probability extraordinary capacity is available.
Abstract: This paper is motivated by the need for fundamental understanding of ultimate limits of bandwidth efficient delivery of higher bit-rates in digital wireless communications and to also begin to look into how these limits might be approached. We examine exploitation of multi-element array (MEA) technology, that is processing the spatial dimension (not just the time dimension) to improve wireless capacities in certain applications. Specifically, we present some basic information theory results that promise great advantages of using MEAs in wireless LANs and building to building wireless communication links. We explore the important case when the channel characteristic is not available at the transmitter but the receiver knows (tracks) the characteristic which is subject to Rayleigh fading. Fixing the overall transmitted power, we express the capacity offered by MEA technology and we see how the capacity scales with increasing SNR for a large but practical number, n, of antenna elements at both transmitter and receiver. We investigate the case of independent Rayleigh faded paths between antenna elements and find that with high probability extraordinary capacity is available. Compared to the baseline n = 1 case, which by Shannon‘s classical formula scales as one more bit/cycle for every 3 dB of signal-to-noise ratio (SNR) increase, remarkably with MEAs, the scaling is almost like n more bits/cycle for each 3 dB increase in SNR. To illustrate how great this capacity is, even for small n, take the cases n = 2, 4 and 16 at an average received SNR of 21 dB. For over 99% of the channels the capacity is about 7, 19 and 88 bits/cycle respectively, while if n = 1 there is only about 1.2 bit/cycle at the 99% level. For say a symbol rate equal to the channel bandwith, since it is the bits/symbol/dimension that is relevant for signal constellations, these higher capacities are not unreasonable. The 19 bits/cycle for n = 4 amounts to 4.75 bits/symbol/dimension while 88 bits/cycle for n = 16 amounts to 5.5 bits/symbol/dimension. Standard approaches such as selection and optimum combining are seen to be deficient when compared to what will ultimately be possible. New codecs need to be invented to realize a hefty portion of the great capacity promised.

10,526 citations

Journal ArticleDOI
TL;DR: In this paper, the authors consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas and derive performance criteria for designing such codes under the assumption that the fading is slow and frequency nonselective.
Abstract: We consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas. Data is encoded by a channel code and the encoded data is split into n streams that are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by noise. We derive performance criteria for designing such codes under the assumption that the fading is slow and frequency nonselective. Performance is shown to be determined by matrices constructed from pairs of distinct code sequences. The minimum rank among these matrices quantifies the diversity gain, while the minimum determinant of these matrices quantifies the coding gain. The results are then extended to fast fading channels. The design criteria are used to design trellis codes for high data rate wireless communication. The encoding/decoding complexity of these codes is comparable to trellis codes employed in practice over Gaussian channels. The codes constructed here provide the best tradeoff between data rate, diversity advantage, and trellis complexity. Simulation results are provided for 4 and 8 PSK signal sets with data rates of 2 and 3 bits/symbol, demonstrating excellent performance that is within 2-3 dB of the outage capacity for these channels using only 64 state encoders.

7,105 citations

Journal ArticleDOI
TL;DR: In this paper, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques.
Abstract: It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

2,974 citations

Proceedings Article
01 Jan 1991
TL;DR: It is concluded that properly augmented and power-controlled multiple-cell CDMA (code division multiple access) promises a quantum increase in current cellular capacity.
Abstract: It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

2,951 citations