Subcarrier Allocation Algorithm Based on Greedy-Like in Multi Carrier Code Division Multiple Access Systems

One of the most important issues to be taken into consideration in multi carrier communication systems with multi users is the assignment of the available resources to the users efficiently. Thus, how to determine the number of subcarriers to be allocated to the users has an important role with regards to data rate and error performance of the system when active users are increased in multi carrier system. In this study by using Greedy-Like algorithm, the subcarriers in MCCDMA systems are optimal allocated to the users and the efficiency of this algorithm compared with other algorithms in terms of bit error and bit rate performance

Hardware Impairments Aware Transceiver Design for Bidirectional Full-Duplex MIMO OFDM Systems

In this paper we address the linear precoding and decoding design problem for a bidirectional orthogonal frequencydivision multiplexing (OFDM) communication system, between two multiple-input multiple-output (MIMO) full-duplex (FD) nodes. The effects of hardware distortion as well as the channel state information error are taken into account. In the first step, we transform the available time-domain characterization of the hardware distortions for FD MIMO transceivers to the frequency domain, via a linear Fourier transformation. As a result, the explicit impact of hardware inaccuracies on the residual selfinterference (RSI) and inter-carrier leakage (ICL) is formulated in relation to the intended transmit/received signals. Afterwards, linear precoding and decoding designs are proposed to enhance the system performance following the minimum-mean-squarederror (MMSE) and sum rate maximization strategies, assuming the availability of perfect or erroneous CSI. The proposed designs are based on the application of alternating optimization over the system parameters, leading to a necessary convergence. Numerical results indicate that the application of a distortionaware design is essential for a system with a high hardware distortion, or for a system with a low thermal noise variance.Comment: Submitted to IEEE for publicatio

A Subcarrier and Power Allocation Algorithm for OFDMA Full-Duplex Systems

In this paper, we focus on subcarrier and power allocation for an orthogonal frequency division multiple access (OFDMA) full-duplex (FD) system. A three-step algorithm is proposed to maximize the sum-rate of the system subject to individual rate constraints at the uplink and downlink users, and transmit power constraints at the base station (BS) and uplink users. The steps are: 1) Subcarrier allocation that considers user target rate requirements, 2) residual subcarrier allocation that further increases the sum rate, and 3) power allocation based on iterative water-filling (IWF). Simulation results reveal that the proposed FD scheduling improves the sum-rate over thetraditional half-duplex (HD) and round-robin (RR) scheduling significantly under the self-interference cancellation levels that has been recently achieved