In this paper, we consider the frequency offset estimation for Orthogonal Frequency-Division Multiple Access (OFDMA) uplink (UL) transmissions. We first analyze the negative effect of Multi-Access-Interference (MAI) on OFDMA UL, and then propose two interference reduction/elimination methods, i.e., the Reduced-Rank-Projector (RRP) and Shift-Sampling-Projector (SSP) methods, to eliminate/reduce ...

© 2014 Yonghoon Choi 953 http://dx.doi.org/10.4218/etrij.14.0113.0843 This paper studies the uplink resource allocation for multiple radio access (MRA) in reconfigurable radio systems, where multiple-input and multiple-output (MIMO) multicarrier-code division multiple access (MCCDMA) and MIMO orthogonal frequency-division multiple access (OFDMA) networks coexist. By assuming multi-radio user eq...

Abstract — This paper analyzes the performance of an orthogonal frequencydivision multiple access (OFDMA) scheme in which the carriers assigned to a user are uniformly spaced across the channel bandwidth and code-division multiplexing is used between them. Zero forcing and minimum mean-square error equalization and maximum-likelihood detection are used to compensate for multipath fading. It is ...

We investigate the sensitivity to carrier phase jitter of an orthogonal frequency-division multiple access (OFDMA) system. When all OFDMA carriers have the same power level and the jitter spectrum, the degradation caused by the jitter is shown to be equal to the degradation of an OFDM system. Also, traditional FDMA is found to be slightly more robust than OFDMA. I. System description. Orthogona...

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...