In this contribution, the performance of wideband code-division multiple-access (W-CDMA) systems using space-timespreading(STS-) based transmit diversity is investigated, when frequency-selective Nakagami-m fading channels, multiuser interference, and background noise are considered. The analysis and numerical results suggest that the achievable diversity order is the product of the frequency-s...

The main objective of this project is to design the full-rate Space-Time-Frequency Trellis code (STFTC), which is based on Quasi-Orthogonal designs for Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems. The proposed Quasi-Orthogonal Space-Time-Frequency Trellis code combines set partitioning and the structure of quasi-orthogonal space-frequency desi...

Abstract Multi-carrier direct sequence code division multiple access (MC DS-CDMA) is a combination of time-domain spreading and orthogonal frequency division multiplexing (OFDM), while multi-carrier code division multiple access (MC-CDMA) is a combination of frequency-domain spreading and OFDM. In MC-CDMA, a good bit error rate (BER) performance can be achieved by using frequency-domain equaliz...

Most empirical studies support a decline in speciation rates through time, although evidence for constant speciation rates also exists. Declining rates have been explained by invoking pre-existing niches, whereas constant rates have been attributed to non-adaptive processes such as sexual selection and mutation. Trends in speciation rate and the processes underlying it remain unclear, represent...

In this paper, a type of multi-carrier direct sequence code division multiple access (MC-DS-CDMA) system which uses frequency spread coding is proposed and investigated for the down-link. An MC-DS-CDMA system is a combined system of CDMA and multi-carrier modulation. This system is often categorized as a “serial to parallel (S/P) type” system because serial to parallel converted data symbols ar...

This paper addresses the tradeoff issues in OFDMA uplink data channel design. For fixed and portable applications where the propagation channels are near static, we show that maximum throughput can be achieved through intelligent channel allocation when uplink channels are configured with minimum frequency diversity. The total uplink throughput under different configurations is presented. For m...

The relative abilities of word frequency, contextual diversity, and semantic distinctiveness to predict accuracy of spoken word recognition in noise were compared using two data sets. Word frequency is the number of times a word appears in a corpus of text. Contextual diversity is the number of different documents in which the word appears in that corpus. Semantic distinctiveness takes into acc...

Multiple input multiple output (MIMO) communication systems with orthogonal frequency division multiplexing (OFDM) modulation have a great potential to play an important part in the design of the next generation broadband wireless communication system. In this paper, the bit error rate (BER) performance using linear maximum likelihood alamouti combiner (LMLAC) decoding technique for space time ...