Open access

Crest Factor Reduction of an OFDM/WiMAX Network

By Sheila Mugala, Julius Butime, and Dorothy Okello (June 2012, Department of Electrical and Computer Engineering, School of Engineering, Art, Design and Technology (CEDAT), Makerere University, Uganda )

African countries lag behind the rest of the world in their use of Information and Communication Technologies (ICTs). To reduce the digital divide quickly and cost-effectively, wireless networks are considered. WiMAX (Worldwide Interoperability for Microwave Access) is a wireless broadband access technology that uses Orthogonal Frequency Division Multiplexing (OFDM) which is a multicarrier modulation scheme. OFDM presents a problem of a high crest factor or Peak to Average Power Ratio (PAPR). To circumvent this problem either High Power Amplifiers (HPAs) with large dynamic range or PAPR reduction techniques are used. The former scheme increases cost of the system while the latter introduces redundancy or distortion. A novel PAPR reduction scheme is presented. It is a combination of the ideas of Tone Reservation and Selected Mapping. The advantage of this scheme is that it has a lower complexity. It is simulated for a WiMAX system.

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Making government accountable to citizens in Uganda and the region

PERGAMINO 30 May 2012 (FF for APCNews)

Lillian Nalwoga from the Collaboration on International ICT Policy in East and Southern Africa (CIPESA) coordinated research on open governance data in Uganda as part of APC’s Action Research Network project. “Citizens, academia, the private sector and civil society need to be more involved in the implementation of open governance,” says Nalwoga in an interview with APCNews.

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Developing countries utilise cost-effective option to bridge access gap

PERGAMINO 25 May 2012 (FF for APCNews)

APCNews interviewed Ermanno Pietrosemoli from EsLaRed and Russel Southwood from Balancing Act on some of the issues covered during a workshop organised by APC at the recent WSIS Forum in Geneva. Both agreed that workshops on TV white spaces sensitises stakeholders to deal with spectrum allocation from an important perspective that supersedes commercial interests.

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WSIS Forum 2012: TV White Spaces on the agenda

PERGAMINO 4 May 2012 (FF for APCNews)

From 14-18 May Geneva will be hosting the WSIS Forum 2012, where the Association for Progressive Communications has organised two thematic workshops on May 17th, one of them under the subject Television White Spaces.

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Debate over spectrum in Argentina: “A defining push is needed to get past the debate stage”

MONTEVIDEO 21 March 2012 (AF for APCNews)

Although in Argentina a debate does exist on the spectrum, it prioritises aspects related to broadcasting and obscures those related to telecommunications. Florencia Roveri and Flavia Fascendini of Nodo Tau clarify this issue in this interview conducted as part of the “Open spectrum for development” project.

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Open spectrum in Peru: Capitalising on an opportunity to democratise access to the internet

MONTEVIDEO 21 March 2012 (AF for APCNews)

In an interview with APC, Maicu Alvarado and Gabriela Perona of CEPES share experiences of using the spectrum with a positive social impact and offer guidelines for thinking collectively about policies for managing the spectrum that aim for more than simply economic growth.

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Spectrum management in Venezuela lacks clear policy objectives

MONTEVIDEO 21 March 2012 (AF for APCNews)

In Venezuela, community uses of the spectrum are privileged at the cost of generating uncertainty in the private sector. This discourages major investments in telecommunications and a wider discussion of the subject, according to Sandra Benítez and Ermanno Pietrosemoli of EsLaRed in this interview with APC.

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Open spectrum in Ecuador: The debate must extend beyond the circle of experts

MONTEVIDEO 21 March 2012 (AF for APCNoticias)

Lack of knowledge about the ways that policies relating to the spectrum affect people’s lives is one of the primary obstacles for the participation of civil society in the regulatory debate. Marco Navas Alvear promotes solutions for this problem in this interview by APC as part of the “Open spectrum for development” project.

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Colombia redefines its spectrum management plan

MONTEVIDEO 20 March 2012 (AF for APCNews)

Management of the spectrum in Colombia is migrating towards a more flexible and participatory model. Nevertheless there is still a need for greater involvement of community media and social organisations as a counterweight to the voice of the commercial operators in discussions on the management of the spectrum, according to Lilian Chamorro of Colnodo, in this interview with APC.

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Spectrum use in Latin America: Summary report of the case studies of Argentina, Brazil, Colombia, Ecuador, Peru and Venezuela

By Carlos A. Afonso (November 2011, APC )

In Latin America case studies were done in Argentina, Brazil, Colombia, Ecuador, Peru and Venezuela. This report reviews and summarises the most relevant aspects of these studies.

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