1,721,049 research outputs found
Throughput efficient block-spreading CDMA: sequence design and performance comparison
No full textIn this paper we propose a new multiple user architecture for broadband wireless communications based on code division multiple access, denoted block CDMA (B-CDMA). The B-CDMA transmitter spreads the data on a block basis and a single cyclic prefix is used at the end of each spread block. We investigate the orthogonality of spreading sequences for B-CDMA, for an uplink broadband transmission and we design sequences that minimize the power of multiuser access interference. Equalization of the received signal is performed through an iterative block decision feedback equalizer (IBDFE). The B-CDMA system is compared to existing block spreading schemes in terms of achievable throughput for a wireless broadband uplink transmission
Cost-benefit evaluation of voltage conditioners installation in industrial and commercial power systems
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Analisi comparata dei costi di differenti tipologie di cablaggio per una distribuzione a bassissima tensione in corrente continua
No full textInterference resilient block-spreading CDMA with minimum MAI sequence design
No full textCode-division multiple-access (CDMA) schemes based on block spreading implement the spreading of entire data blocks rather than single symbols, thus achieving a higher robustness against the frequency selectivity of the channel and allowing the use of efficient modulation/equalization schemes operating in the frequency domain (FD). In this paper, we present a new block CDMA (B-CDMA) system where a single cyclic prefix (CP) is used at the end of each spread block. This provides a higher spectral efficiency with respect to existing schemes. By observing that complete orthogonality among users is achievable only for half-loaded systems on dispersive channels, we introduce new criteria for the design of spreading and despreading sequences, which aim at minimizing the mean-square error at the output of the despreader. For the equalization of the received signal, we propose an iterative block decision feedback equalizer, which iterates between equalization and decoding. Equalization filters are designed to minimize the mean-square error,and take into account the residual interference due to the nonorthogonality of the spreading sequences. The performance of B-CDMA is evaluated in an uplink wireless scenario and compared to existing CDMA schemes
Reply to: Correspondence on simulation of the cathodic protection of extended buried conductor networks
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Improving power quality by sub-cycle transfer switches: a criterion for the evaluation of alternate sources independence
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