Sherlie Portugal

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IMT-Advanced mobile communication systems make it possible for any devices to access high-speed networks anytime and anywhere. To meet the needs of IMT-Advanced systems, cellular systems must solve the problem of intercell interference caused by frequency 123 C. You et al. reuse. Intercell interference problems become severe when orthogonal frequency(More)
request, provided it is not made publicly available until 12 months after publication. Abstract The rapid growth in mobile communication users necessitates the development of reliable communication systems that provide higher data rates. To meet these requirements, techniques such as multiple input multiple output (MIMO) and orthogonal frequency division(More)
SUMMARY In recent years, techniques such as multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) have been developed and combined in MIMO-OFDM systems to provide higher data rates. In addition, the system can be optimized by setting modulation and coding adaptively according to the channel conditions. The overall(More)
Sphere decoding is a technique able to achieve the optimal performance of the maximum likelihood decoder, but its high and variable complexity can make the practical implementation infeasible. In this paper, we present an adaptive system, called adaptive SD-OSIC, as a way of reducing the decoding complexity while maintaining the error performance of(More)
Sphere decoding is a decoding technique able to achieve the maximum likelihood error performance in fading environments; nevertheless, it exhibits a high complexity, especially in poor channel conditions. In this paper, we present an adaptive hybrid algorithm which reduces the complexity of conventional sphere decoding without sacrificing its error(More)
The latest wireless communication systems focus on developing MIMO-OFDM systems that allow the transmission of very high data rates in fading environments. We can optimize these systems even further by setting the modulation and coding adaptively according to the channel conditions, and by using sub-carrier frequency and power allocation techniques. The(More)
The MIMO-OFDM Adaptive MCM System changes MIMO scheme, channel coding rate, and modulation scheme, adaptively, according to the channel conditions. And the addition of Pre-coding and Antenna Subset Selection assures a better performance and higher data rate. The MIMO-OFDM Adaptive MCM System achieves a better average throughput performance than a Non(More)
In this paper, we proposed a system that combines AMC and MIMO schemes. While conventional AMC system changes only the coding rate and modulation, the proposed Adaptive-MCM system also selects the MIMO scheme (diversity, multiplexing) according to channel condition. Furthermore, by applying pre-coding and antenna subset-selection we not only produce optimal(More)
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