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This paper analyzes the performance of a large-scale multiuser multiple-input multiple-output (MU-MIMO) system with amplify-and-forward (AF) relaying in the presence of co-channel interference. Each user terminal (UT) has a single antenna while the relay is equipped with very large antenna arrays. To evaluate the impact of large number of relay antennas on the performance of the considered system,...
We propose decentralized relay coordination algorithms and corresponding channel state information (CSI) signaling concepts for weighted sum rate maximization, via linear downlink transceiver optimization in multiuser multi-relay MIMO network. Two decentralized algorithms are developed with the local CSI requirements at the base station and the relay nodes. In the first proposed algorithm, the generalized...
In conventional amplify-and-forward relay networks, relays retransmit signals with predetermined transmit power and amplification factors assuming perfect channel knowledge. This paper proposes a relay selection scheme with amplification factor optimization according to the minimum mean square error criterion when the channel state information is imperfect due to the channel estimation error. Relays...
Green radios have drawn much attention in recent years. This paper derives the energy per good-bit expressions for MQAM and MPSK in DF relay networks under AWGN and Rayleigh fading channels. The energy per good-bit is defined as the energy per correctly received bit, which indicates that the energy consumed per bit as well as the link reliability and retransmission probabilities are considered. An...
In this paper, we investigate the power saving issue in cognitive radio (CR) multi-hop relay network. Due to the dynamic property of the wireless channel, the quality of service (QoS) guarantee for multi-hop transmission is quite challenging. To deal with these problems, automatic repeat-request (ARQ) protocol in an end-to-end manner is incorporated. For multi-hop transmission evaluation purpose,...
This paper addresses the linear processing issues for two way non-regenerative MIMO relay systems with multiple antennas at each node. Based on theoretical derivation, we first propose an optimal joint iterative linear processing scheme for the relay node and receiving source nodes, aiming to minimize the total mean squared error (MSE). The convergence of this iterative algorithm is proved in terms...
In the spectrum sharing systems, an unlicensed (secondary) user may share a frequency band with its licensed (primary) user as long as its transmission does not interfere with the primary user's communications. For the cognitive wireless relay networks, this interference regulation from the primary user may affect its cooperative scheme. In this paper, we investigate the outage performance of cognitive...
In this paper, we consider a four-node relay-based OFDMA system. The expression of the upper bound for the achievable rate in Successive Relaying (SUR) protocol is derived by using the cut-set theorem for half-duplex systems. Based on this expression, the near-optimal solution of the achievable rate is obtained in the joint power and subcarrier allocation constraint, according to the dual problem...
In order to obtain a more accurate assessment of relay performance in real-world outdoor propagation environment and to provide guidelines for the relay-based system deployment in the IMT-Advanced frequency band, the performance of a variety of relay schemes is investigated based on wideband measurements. The measurements were conducted at 2.35 GHz with 50 MHz bandwidth, which is within the frequency...
In this paper, we propose a relay selection scheme based on cooperative MIMO (multi-input-multi-output) communication for network lifetime maximization in energy-constrained sensor networks. Compared with existing work, our distributions are: cooperative nodes choice is not based on minimizing energy consumption per communication but balancing remaining energy between participants including source...
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