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In order to use frequency spectrum efficiently, many methods for increasing the data rate and improving the signal purity of spectrum in communication systems have been studied (Haykin, S., 1994). Recently how to advance the spectrum policy for the efficient use of frequency resources in the future was investigated [2]. According to the results of the study, we can increase the efficiency of using...
Advances in micromachining technology can facilitate the integration of SAW (Surface Acoustic Wave) devices and CMOS circuitry on IC scale substrate for Monolithic fabrication. The optimal design and performance of these filters can be reached by using new Smart materials. The key component in the structure of the SAW device is the piezoelectric materials used which depends mainly on some important...
The paper presents the design and implementation of input/output interface circuits, fully compatible with low-voltage differential signal (LVDS) standard. Due to the low voltage differential transmission technique, the low power consumption and high transmission speed are achieved at the same time. The transmitter is implemented by a closed-loop control circuit and an internal bandgap voltage reference,...
In this paper, we propose a robust STBC transmission scheme to combat the timing synchronization errors over frequency-selective multiple-access channels. First, the equivalent channel model in the presence of timing synchronization errors is derived and we find that the synchronization errors result in an equivalent channel model with larger number of correlated channel taps. Based on this correlated...
Some communication applications, like multimedia, deliver data of different importance classes allowing unequal error protection (UEP) levels. In this paper, a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM) is considered with a new UEP bit-loading algorithm based on the non-UEP algorithm by Chow, Cioffi, and Bingham. In the proposed bit-loading...
This paper discusses the performance of the wavelet based filtered multi-tone (WFMT) modulation. The novel WFMT modulation was proposed in 2003 for improving characteristics of wireless and DSL multicarrier systems. In this paper we describe a main idea of WFMT and discuss the advantages of this novel modulation. The WFMT modulation in comparison with OFDM and DMT has low level of out-of-band side...
Effects of improved channel estimation are studied for a proposed IEEE 802.11n OFDM MIMO system. Three channel estimation methods are considered: maximum likelihood (ML), time-domain truncation (TDT) and model-based (MB). TDT and MB are particularly useful when the channel delay spread is short. For an MMSE receiver, MB shows a 1-2.5 dB improvement over ML on the packet error rate performance for...
Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a...
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