Physical layer security is an attractive security mechanism, which exploits the randomness characteristics of wireless transmission channel to achieve security. However, it is hampered by the limitation of the channel condition that the main channel must be better than the eavesdropper channel. To alleviate the limitation, cooperative communication is introduced. Few studies have investigated t...

In this paper, we study the interference relay-without-delay channel which is an interference channel with a relay helping the communication. We assume the relay’s transmit symbol depends not only on its past received symbols but also on its current received symbol, which is an appropriate model for studying amplify-and-forward type relaying when the overall delay spread is much smaller than th...

This paper studies the transceiver design of the Gaussian two-pair two-way relay channel (TWRC), where two pairs of users exchange information through a common relay in a pairwise manner. Our main contribution is to show that the capacity of the Gaussian two-pair TWRC is achievable to within 1 2 bit for arbitrary channel conditions. In the proof, we develop a hybrid coding scheme involving Gaus...

This article considers uniand bidirectional communication in the half-duplex Gaussian multiple-input multiple-output (MIMO) relay channel. Assuming perfect channel state information at all nodes and the use of time division duplex communications protocol to separate transmissions and receptions at all nodes, we propose a dual decomposition approach to efficiently determine upper and lower bound...

With the fast development of communication networks, cooperative communication has been more widely used in many different fields, such as satellite networks, broadcast networks, internet and so on. Therefore relay channels have been playing a pivotal role since their definitions were proposed by Van-der Meulen. However, the general achievable rate region of a relay channel is still unknown whi...

Optimal precoding in the relay is investigated to maximize ergodic capacity of a multiple antenna relay channel. The source and the relay nodes are equipped with multiple antennas and the destination with a single antenna. It is assumed that the channel covariance matrices of the relay’s receive and transmit channels are available to the relay, and optimal precoding at the relay is investigated...

This paper studies the problem of detecting a potential malicious relay node by a source node that relies on the relay to forward information to other nodes. The channel model of two source nodes simultaneously sending symbols to a relay is considered. The relay is contracted to forward the symbols that it receives back to the sources in the amplify-and-forward manner. However there is a chance...

In this paper, we derive a new achievable rate region for the user cooperation channel, which exceeds the best known result for this channel [Wil83]. Since the user cooperation channel includes many other known channels as a special case, the new rate region provides an improved achievable rates for many of the special cases (discussed later). The most notable example is that of the Gaussian re...

The Multiple-access Relay Channel (MARC) has been considered as a promising technique in next generation wireless communication networks. In this work, we study a Network Coding based Multiaccess Relay Channel (NC-MARC) where a decode-and-forward relaying and a static XOR network coding are considered for the one-way relaying system. The system consists of two transmitters communicating with a ...

Relaying (1–3) has been considered as a paradigm for improving the quality of service (i.e., bit-error-rate, data rate and coverage) in wireless networks. In this work, we study a two-hop relay channel in which each node can have multiple antennas. It is well-known that utilizing multiple-input multiple-output (MIMO) links can significantly improve the transmission rate (see e.g. (4; 5) and ref...