The resource allocation problem for the downlink of Orthogonal Frequency Division Multiple Access (OFDMA) wireless multicast systems is investigated. It is assumed that the Base Station (BS) consists of multiple antennas in a Distributed Antenna System (DAS), whereas each user is equipped with a single antenna. The multicasting technology is able to support several groups of users with flexible...

Future wireless networks need to address the predicted growth in mobile traffic volume, expected to have an explosive growth in the next five years mainly driven by video and web applications. Transmission schemes based on Orthogonal Frequency Division Multiple Access (OFDMA) combined with Space Division Multiple Access (SDMA) techniques are key promising technologies to increase current spectr...

White light emitting diode (WLED) technology has been regarded as an environment-friendly lighting in the future. The WLED lighting system is able to provide short range wireless communication while illuminating rooms. The WLED based visible light communication (VLC) systems employing orthogonal frequency division multiplexing access (OFDMA) technique has been investigated in many researches. H...

This paper proposes an optimized scheduling scheme in OFDMA-based WiMax networks to achieve both optimized system throughput and a complete QoS implementation for various types of traffic flows. Our scheduling scheme includes two components, one is the resource allocation for each user; the other is the QoS scheduling for various traffic sessions. Specifically an optimization problem is formula...

Next-generation 802.11ax WLANs will make extensive use of multi-user communications in both downlink (DL) and uplink (UL) directions to achieve high and efficient spectrum utilization in scenarios with many user stations per access point. It will become possible with the support of multi-user (MU) multiple input, multiple output (MIMO) and orthogonal frequency division multiple access (OFDMA) t...

In this article, a hybrid multi-user OFDMA scheme which considers different user demands regarding channel access and user-specific imperfect channel quality information (CQI) is analytically described and evaluated. The considered hybrid scheme offers two possible modes to serve the user: firstly, via a non-adaptive mode which applies a discrete Fourier transform precoding to exploit frequency...

The increase in internet traffic, number of users, and availability of mobile devices poses a challenge to wireless technologies. In long-term evolution (LTE) advanced system, heterogeneous networks (HetNet) using centralized coordinated multipoint (CoMP) transmitting radio over optical fibers (LTE A-ROF) have provided a feasible way of satisfying user demands. In this paper, an orthogonal wave...

This paper compares the information rate achieved by SC-FDMA (single-carrier frequency-division multiple access) and OFDMA (orthogonal frequency-division multiple access), where a linear frequency-domain equalizer is assumed to combat frequency selective channels in both systems. Both the single user case and the multiple user case are considered. We prove analytically that there exists a rate ...

LTE (long term evolution) is come to meet our desired high speed data communication.LTE is the last step toward the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile telephone networks. Where the current generation of mobile telecommunication networks are collectively known as 3G (for "third generation"), LTE is marketed as 4G. LTE uses Orthogonal F...

We propose an efficient control channel resource allocation approach to enhance the performance of voice-over-IP (VoIP) in orthogonal frequency division multiple access(OFDMA-) based next generation mobile communication systems. As the long-term evolution (LTE) of universal terrestrial radio access network (UTRAN), evolved UTRAN (E-UTRAN) is the first OFDMA-based packet radio network and thus s...