In this letter, a novel blind CFO estimation algorithm for the uplink of an OFDMA system is proposed. The proposed method exploits the inherent redundant information in OFDMA symbols and does not require additional pilot or preamble overhead. Since it is a post-FFT estimator, it does not use filter banks to separate the desired user’s signal from the others in the time domain. Hence, the subcar...

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...

Orthogonal Frequency-Division Multiple Access (OFDMA) is a multi-user version of the Orthogonal frequency-division multiplexing (OFDM). OFDMA is used in the mobility mode of IEEE 802.16 WirelessMAN Air Interface standard, commonly referred to as WiMAX. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users [1], [2]. The performance of these systems depend o...

Welcome to this special issue of the EURASIP Journal on Wireless Communications and Networking (JWCN). This special issue is devoted to the topic of the latest research and development on Orthogonal Frequency-Division Multiple Access (OFDMA) from physical and network layers to practical applications. OFDMA technologies are currently attracting intensive attention in wireless communications to m...

The problem of multiservice transmission in OFDMA-based cooperative relay networks is studied comprehensively. We propose a framework to adaptively allocate power, subcarriers, and data rate in OFDMA system to maximize spectral efficiency under the constraints of satisfying multiuser multiservices’ QoS requirements. Specifically, first we concentrate on the single-user scenario which considers ...

The Long term Evolution (LTE) Uses Orthogonal Frequency Division Multiple Access (OFDMA) in the downlink and Single Carrier Frequency Division Multiple Access (SCFDMA) in the uplink. This paper introduces the transceiver of OFDMA and SCFDMA, discusses difference between the OFDMA and SCFDMA, and highlight the factor that leverages the performance of both multiple access technique, the graphical...

As the power consumption is an essential issue for designers of mobile devices The 3 Generation Partnership Project (3GPP) – Long Term Evolution (LTE) employs a multicarrier communication technique on the air interface, Single Carrier Frequency Division Multiple Access (SCFDMA), in uplink scenario and Orthogonal Frequency Division Multiple Access (OFDMA) in the downlink. SCFDMA core modulation ...

A two-way relay network provide improved spectral efficiency compared with a conventional one-way relay network by using either superposition coding or network coding. OFDMA network provides imptoved performance by adaptive resource allocation. In this paper, we propose a adaptive subcarrier allocation for a multiuser two-way OFDMA relay network. In the proposed algorithm, subcarriers are alloc...

IEEE 802.16-2004 and IEEE 802.16e-2005 standards specify OFDMA as a physical layer technique for fixed and nomadic BWA systems, respectively. OFDMA is very sensitive to time and frequency offsets. In this paper, a preamble based downlink frame synchronization method for OFDMA mode of WMAN is analyzed in frequency selective fading channels. Expressions for mean and variance of the metric are der...

In this paper, our focus is to assure a global frequency synchronization in OFDMA-based wireless mesh networks with local information. To acquire the global synchronization in distributed manner, we propose a novel distributed frequency synchronization (DFS) method. DFS is a method that carrier frequencies of distributed nodes converge to a common value by repetitive estimation and averaging st...