نتایج جستجو برای: subcarrier multiplexing

تعداد نتایج: 18581  

2014
K. Sumathi M. L. Valarmathi

In this paper a novel cross layer resource allocation for downlink transmission with heterogeneous traffic in wireless networks is developed. The problem of efficient resource allocation for multiuser orthogonal frequency division multiplexing over Rayleigh fading channels is addressed. Subcarrier and power allocation are carried out sequentially to reduce the complexity. Assuming that the base...

Journal: :Wireless Personal Communications 2008
Matthias Wetz Ivan Perisa Werner G. Teich Jürgen Lindner

We present an OFDM-based transmission scheme which is suitable for robust transmission in fast fading environments, where a reliable channel estimate is impossible or very difficult to obtain. Our scheme is based on the combination of noncoherently detected MFSK (M-ary frequency shift keying) and OFDM (orthogonal frequency division multiplexing). Noncoherent detection of OFDM-MFSK allows an arb...

2001
Zuqing Zhu V. J. Hernandez Min Yong Jeon

This paper provides theoretical and experimental studies of radio-frequency (RF) photonics processing techniques applicable in subcarrier-multiplexed optical-label switching (OLS) communications systems. The paper provides an overview of various label-coding technologies and introduces subcarrier multiplexing (SCM) as an attractive technology for OLS networks. All-optical-label extraction using...

2015
Mohammad Kamrul Hasan Ahmad Fadzil Ismail Aisha-Hassan Abdalla Wahidah Hashim Shayla Islam

To extend the coverage and capacity of Heterogeneous Networks (HetNets), femtocells (HeNodeBs) has been impressive to deploy in in-house or apartment. Owing to co-channel spectrum involvement these HeNodeB sources CoTier interference (CTI) with neighbor HeNodeBs and users of HeNodeB (HUE) in orthogonal frequency division multiplexing Access (OFDMA). As a result, CTI is occurred which causes of ...

Journal: :J. Electrical and Computer Engineering 2012
Mohamed Hossam Ahmed Octavia A. Dobre Rabie K. Almatarneh

This paper provides an analytical evaluation of the performance of proportional fair (PF) scheduling in Orthogonal FrequencyDivision Multiple Access (OFDMA) wireless systems. OFDMA represents a promising multiple access scheme for transmission over wireless channels, as it combines the orthogonal frequency division multiplexing (OFDM) modulation and subcarrier allocation. On the other hand, the...

Journal: :IEEE Transactions on Vehicular Technology 2021

Emerging digital radar concepts such as orthogonal frequency-division multiplexing (OFDM) allow flexible signal generation. This opens up new opportunities in waveform design a multiple-input multiple-output (MIMO) system introducing coding for multiplexing. In this article, coded MIMO OFDM waveforms are proposed and investigated that continuous simultaneous wideband transmission all transmitte...

2012
Liaoyuan Zeng Sean McGrath

Ultra Wideband (UWB) system is overlapped with various wireless systems, such as WLAN, WiMax and UMTS, which limits the use of UWB. Cognitive Radio (CR) enables UWB systems to efficiently use the overlapped spectrum without causing interference to other wireless systems. In this paper, we focuses on the low-complexity joint optimization algorithm design with respect to transmit power allocation...

2012
Sebastian Aust Andreas Ahrens César Benavente-Peces

Multicarrier transmission such as OFDM (orthogonal frequency división multiplexing) is an established technique for radio transmission systems and it can be considered as a promising approach for next generation wireless systems. However, in order to comply with the demand on increasing available data rates in particular in wireless technologies, systems with múltiple transmit and receive anten...

Journal: :EURASIP J. Wireless Comm. and Networking 2006
Diakoumis P. Gerakoulis George P. Efthymoglou

Themulticarrier orthogonal code divisionmultiplexing (MC-OCDM) introduced here has been designed for very wide bandwidth (VWB) point-to-point and point-to-multipoint transmission. In order to meet VWB transmission requirements, the MC-OCDM design has two components, the basic and the composite. The basic MC-OCDM is a generalized form of the standard orthogonal frequency division multiplexing (O...

2000
Jinwen Shentu

In this paper we introduce a new method of carrier frequency offset estimation for Orthogonal Frequency Division Multiplexing (OFDM) communication systems. The method uses one or more pairs of adjacent subcarriers within an OFDM symbol. The pairs of subcarriers are modulated with equal amplitude and opposite polarity. In the absence of frequency offset, the received subcarrier pairs also have e...

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