A novel bit-detect-and-forward (BDF) relaying scheme based on repetition coding with the relay is proposed, significantly improving the robustness to impairments proper to free-space optical (FSO) communications such as unsuitable alignment between transmitter and receiver as well as fluctuations in the irradiance of the transmitted optical beam due to the atmospheric turbulence. Closed-form as...

Although multiple-input multiple-output (MIMO) is advantageous on orthogonal frequency division multiple access (OFDMA) system, it may not be possible that practical systems have more than two antennas because of size and cost. Therefore, cooperative communication has been recently proposed as a way to overcome this problem in slow fading wireless environment. However, if cooperative communicat...

In this paper, we investigate the secrecy outage probability (SOP) for the cooperative amplify-and-forward (AF) two-way relay networks (TWRN) with channel estimation (CE) errors under Rayleigh fading channels. In the proposed system, two sources simultaneously broadcast their respective information to all the relays firstly. Then, the optimal relay performs AF protocol on the received signals s...

In this paper, our objective is maximizing total sum-rate subject to power constraints on total relay transmit power or individual relay powers, for amplify-and-forward single-antenna relay-based wireless communication networks. We derive a closed-form solution for the total power constraint optimization problem and show that the individual relay power constraints optimization problem is a quad...

The radio resource allocation in wireless communication is analysed in this paper. Pair of users communicates each other through multiple two way relays in orthogonal frequency division multiplexing transmission systems. The total throughput is maximized by relay selection, channel and relay assignment, subcarrier pairing and subcarrier allocation by prim’s algorithm. The graphical theory appro...

In this paper, a two-stage channel estimation scheme for two-way MIMO relay systems with a single relay antenna is proposed. The backward channel is estimated by using linear minimum mean square estimator (LMMSE) at the first stage, where the optimal training signal is designed. We then mainly focus on the forward channel estimation by using singular value decomposition (SVD) based maximum like...

In this paper multi-carrier transmission schemes applying general waveforms are discussed within two-phase two way relay channels. Here, two users communicate simultaneously on the same resources to an assisting relay. The relay has to cope with the superposition of both users, interferences of the channel and additional practical impairments like frequency and timing offsets. To be more robust...

We investigate the superposition strategy and its usefulness in terms of achievable information theoretic rates. The achievable rate of the superposition of block Markov encoding (decode-forward) and side information encoding (compress-forward) for the three-node Gaussian relay channel is analyzed. It is generally believed that the superposition can out perform decode-forward or compress-forwar...

In this paper, we investigate the individual channel estimation over the three-node one-way relay network (OWRN), where all nodes are equipped with multiple antennas. We first examine the scenario where the relay node is equipped with single antenna. An iterative linear minimum mean-square-error (LMMSE) method, which has fast convergence speed, is proposed to estimate the individual channels. T...

Two-way relay network (TWRN) was introduced to realize high-data rate transmission over the wireless frequency-selective channel. However, TWRC requires the knowledge of channel state information (CSI) not only for coherent data detection but also for the self-data removal. This is partial accomplished by training sequence-based linear channel estimation. However, conventional linear estimation...