نتایج جستجو برای: frequency diversity

تعداد نتایج: 663902  

2015
Hiroyuki MIYAZAKI Fumiyuki ADACHI

In a high mobility environment, single-carrier (SC) space-frequency block coding (STBC) diversity achieves better bit error rate (BER) performance than SC space-time block coding (STBC) diversity. However, in a strong frequency-selective fading channel, the BER performance degrades due to the orthogonality distortion of SFBC codeword. In this paper, we propose a frequency-domain equalization (c...

2004
Hiromichi Tomeba Shinsuke Takaoka

Recently, multi-carrier code division multiple access (MC-CDMA) has been attracting much attention for the broadband wireless access in the next generation mobile communications systems. In the case of uplink transmissions, the orthogonality property among users’ signals is lost since each user’s signal goes through different fading channel and hence, multi-access interference (MAI) is produced...

2003
Marc Kuhn Ingmar Hammerstroem Armin Wittneben

Using a class of recently proposed linear scalable space-time codes we demonstrate the tradeoff between spatial multiplexing and transmit diversity for Rayleigh and Ricean flat fading. The codes are able to use jointly transmit diversity in combination with spatial multiplexing, and they achieve spatial and temporal diversity in Rayleigh and Rice fading environments. Frequency diversity of freq...

Journal: :The Journal of Korean Institute of Communications and Information Sciences 2012

The diversity and richness of species are of important components to evaluate the health of ecologic system of rangelands. This research was conducted to investigate the biodiversity in riparian and neighboring areas via comparison of indices in Javaherdeh rangeland of Ramsar. Plot-transects was randomly used to estimate diversity, richness, dominance, and evenness indices in two regions. Multi...

Gh. Abed Hodtani M. Molavi-Kakhki M. Sheikh-Hosseini,

In this paper we propose a new space diversity scheme for broadband PLC systems using orthogonal space-time block coding (OSTBC) transmission combined with single-carrier frequency-domain equalization (SC-FDE). To apply this diversity technique to PLC channels, we first propose a new technique for combining SC-FDE with OSTBCs applicable to all dispersive multipath channels impaired by impulsive...

2011
Shinya KUMAGAI Ryusuke MATSUKAWA Tatsunori OBARA Fumiyuki ADACHI

Distributed antenna network (DAN) is a promising wireless network which can mitigate the impacts of distancedependent/shadowing losses and fading. Frequency-domain space-time block coded-joint transmit/receive diversity (FDSTBC-JTRD) is an antenna diversity technique which allows an arbitrary number of transmit antennas while keeping the coding rate constant and is suitable for the downlink tra...

Journal: :CoRR 2010
Jinhui Chen Dirk T. M. Slock

This paper presents the impact of frequency diversity on the optimum expected end-to-end distortion (EED) in an outage-free wideband multiple-input multiple-output (MIMO) system. We provide the closed-form expression of optimum asymptotic expected EED comprised of the optimum distortion exponent and the multiplicative optimum distortion factor for high signal-to-noise ratio (SNR). It is shown t...

1998
Akbar M. Sayeed Behnaam Aazhang

We present a new framework for code-division multiple access (CDMA) communication over fast fading mobile wireless channels. The performance of the RAKE receiver, which is at the heart of existing CDMA systems, degrades substantially under fast fading encountered in many mobile scenarios. Due to the time-varying nature of the fast fading channel, we employ joint time-frequency processing, which...

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