Encontrados 49 documentos, a visualizar página 1 de 5

Methylisothiazolinone: second 'epidemic' of isothiazolinone sensitization

Lime-metakaolin mortars for historical buildings repair: study of the hardening...

International Conference Durable Structures: from construction to rehabilitation. Lisbon, LNEC, 31 May-1 June 2012 ; Formulation of mortars with adequate durability and strength is nowadays one of the major challenges in historical buildings repair. Pozzolanic materials have been used during centuries in air lime mortars to improve their mechanic and durability characteristics. This paper is part of an extensi...

Multi-cell cooperation for future wireless systems

Portuguese CADWIN - PTDC/EEA TEL/099241/2008 ; Portuguese Foundation for Science and Technology (FCT)

Channels and parameters acquisition in cooperative OFDM systems

CODIV, FP7/ICT/2007/215477 ; CADWIN, PTDC/EEA – TEL/099241/2008 ; Portuguese Foundation for Science and Technology (FCT)

Sequential symbol synchronizers based on pulse comparison operating by positive...

This work presents the sequential symbol synchronizer based on pulse comparison by positive transitions at quarter rate (txp/4). Their performance is compared with a reference synchronizer by both transitions at the rate (tx). For the reference and proposed synchronizer we consider two versions which are the manual (m) and the automatic (a). The objective is to study the four synchronizers and evaluate their ou...

Frequency-reuse planning of the down-link of distributed antenna systems with m...

Distributed antenna systems (DAS) have been shown to considerably outperform conventional cellular systems in terms of capacity improvement and interference resilience. However, the influence of frequency reuse planning on the performance of DAS remains relatively unknown. To partially fill this gap, this paper presents a comparative analysis of the down-link of DAS versus conventional cellular systems using di...

Distributed antenna system capacity scaling

The distributed antenna system concept promises to enhance the capacity and diversity of next-generation wireless communication networks, due to the inherently added micro and macro diversity. In this article we first give an overview of the main benefits of a DAS in relation to a collocated antenna system. Next we study the sum-capacity scaling of a multi-user DAS with the number of jointly processed transmit ...

Combined distributed turbo coding and space frequency block coding techniques

The distributed space-time (frequency) coding and distributed channel turbo coding used independently represent two cooperative techniques that can provide increased throughput and spectral efficiency at an imposed maximum Bit Error Rate (BER) and delay required from the new generation of cellular networks. This paper proposes two cooperative algorithms that employ jointly the two types of techniques, analyzes ...

Binary dirty paper coding

This paper proposes a practical scheme for implementing binary dirty paper coding (DPC) using a low density generator matrix code (LDGM) concatenated with a high rate low density parity check (LDPC) code. We also propose a new algorithm, a modified version of the belief propagation algorithm (BP), for doing lossy source coding at the encoder, with linear complexity in the block length. In contrast to the superp...

Prefilter bandwidth effects in data symbol phase synchronizers of open loop

This work studies the effects of the prefilter bandwidth on the open loop symbol synchronizers. We consider three different prefilter bandwidth, namely, B1=¥ ( infinite), B2=2.tx and B3=1.tx, where tx is the transmission rate. We consider also four open loop symbol synchronizers, namely, the tank (tank), the SAW (SAW), the monostable (mon), and the astable (ast). The objective is to study the prefilter bandwidt...