نتایج جستجو برای: ofdma

تعداد نتایج: 1595  

Journal: :CoRR 2013
Abdelali El Bouchti Said El Kafhali Abdelkrim Haqiq

IEEE 802.16 OFDMA (Orthogonal Frequency Division Multiple Access) technology has emerged as a promising technology for broadband access in a Wireless Metropolitan Area Network (WMAN) environment. In this paper, we address the problem of queueing theoretic performance modeling and analysis of OFDMA under broad-band wireless networks. We consider a single-cell IEEE 802.16 environment in which the...

2014
SRINIVASA RAO SRINIVAS BABU

Multiple antenna Orthogonal Frequency Division Multiple Access (OFDMA) is a promising technique for the high downlink capacity in the next generation wireless systems, in which adaptive resource allocation would be an important research issue that can significantly improve the performance with guaranteed Quality of Service (QoS) for users. . In this paper we look into the performance of such co...

Journal: :IEICE Transactions 2012
Hsin-De Lin Tzu-Hsien Sang Jiunn-Tsair Chen

For advanced mobile communication systems that adopt orthogonal frequency-division multiple access (OFDMA) technologies, intercarrier interference (ICI) significantly degrades performance when mobility is high. Standard specifications and concerns about complexity demand low-cost methods with deployment readiness and decent performance. In this paper, novel zero forcing (ZF) and minimum mean-sq...

2006
Tobias Frank Anja Klein Elena Costa

In this paper, the performance of Discrete Fourier Transform (DFT) precoded Orthogonal Frequency Division Multiple Access (OFDMA) schemes with interleaved and with blockwise subcarrier allocation is investigated and compared. Transmission with one transmit antenna is compared to transmission with multiple transmit antennas using Cyclic Delay Diversity (CDD). It is shown that the investigated DF...

2009
Mohamed Salah Zaki B. Nossair

Abstract: Single carrier frequency division multiple access (SC-FDMA) which utilizes single carrier modulation at the transmitter and frequency domain equalization at the receiver is a technique that has similar performance and essentially the same overall structure as those of an OFDMA system. One prominent advantage over OFDMA is that the SC-FDMA signal has lower peak-to-average power ratio (...

2014
Sajjan Singh S. V. A. V. Prasad

The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier frequency division multiple access (SCFDMA), scheme for the uplink transmissions and orthogonal frequency division multiplexing access (OFDMA) in downlink. SCFDMA makes use of single carrier modulation and frequency domain equalization, it is a technique that has similar performance and essentia...

Journal: :CoRR 2012
Anatolij Zubow Johannes Marotzke

Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user version of the Orthogonal Frequency Division Multiplexing (OFDM) transmission technique, which divides a wideband channel into a number of orthogonal narrowband subchannels, called subcarriers. An OFDMA system takes advantage of both frequency diversity (FD) gain and frequency-selective scheduling (FSS) gain. A FD gain is ach...

2014
Md. Shamsul Alam

Next generation wireless communication networks are expected to provide ubiquitous high data rate coverage and support heterogeneous wireless services with diverse quality-ofservice (QoS) requirements. This translates into a heavy demand for the spectral resources. In order to meet these requirements, Orthogonal Frequency Division Multiple Access (OFDMA) has been regarded as a promising air-int...

2014
Dah-Chung Chang Yen-Heng Lai

In an OFDMA system, different carrier frequency offsets (CFOs) are possibly raised due to the mismatch of local oscillators and the Doppler effect because of multiple-antenna channels. In spite of an initial CFO synchronization scheme able to be applied at transmitters, the compensation of residual CFOs is required at the receiver in order to eliminate the inter-carrier interference (ICI) for i...

Journal: :EURASIP J. Wireless Comm. and Networking 2009
Hussein M. Alnuweiri Yaser P. Fallah Panos Nasiopoulos Salman Khan

Existing medium access control (MAC) schemes for wireless local area networks (WLANs) have been shown to lack scalability in crowded networks and can suffer from widely varying delays rendering them unsuited to delay sensitive applications, such as voice and video communications. These deficiencies are mainly due to the use of random multiple access techniques in the MAC layer. The design of th...

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