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— In a cooperative network, relays are often closer to the source than the destination and thus the source-relay links have a higher capacity than the source-destination one. In this paper, we investigate a hierarchical modulation-based cooperative scheme, where the relay is able to detect the whole signal, while the destination can only detect the rst(More)
In this work, we explore the introduction of distributed space-time codes in decode-and-forward (DF) protocols. We propose a new Incomplete DF protocol, based on a partial decoding at the relays. This strategy allows the new protocol to bring both full diversity and full symbol rate. Outage probabilities and simulation results show that the Incomplete DF(More)
In this paper, a low-complexity protocol for the K-parallel-path multihop channel is proposed. This protocol is based on a smart path selection combined with a small space-time code. It is proven to schieve full rate and full diversity, and to reach the optimum diversity-multiplexing gain tradeoff d*(r)=K(1-r). Some implementation issues(More)
— In this paper, we propose to implement the dynamic decode-and-forward (DDF) protocol with distributed rotations. In addition to being the first minimum-delay implementation of the DDF protocol proposed for any number of relays, this technique allows to exploit cooperative diversity without inducing the high decoding complexity of a space-time code. The(More)
—Synchronization between the received signals from several transmitters is a challenging problem for cooperative communications. In the literature it is often assumed that the signals are somehow perfectly synchronized, but the problem of communication with asynchronism is rarely addressed. Moreover, in the few works where the problem is addressed, the(More)
We propose some new adaptive amplify-and-forward (AF) and decode-and-forward (DF) protocols using a selection. The new selection criterion is a function of the instantaneous capacities of all possible transmission schemes (with or without cooperation). Outage probabilities and simulation results show that the adaptive cooperation protocols solve the problem(More)
In this paper, we propose a low-complexity method to perform the incomplete decoding needed at relays for the Incomplete Decode-and-Forward. The decoding problem is considered as a diophantine approximation search. We propose two modifications of Cassels' algorithm to approximate an element x Є Q(i,θ) by a linear combination a +(More)
In this work, we explore the introduction of distributed space-time codes in decode-and-forward (DF) protocols. A first protocol named the Asymmetric DF is presented. It is based on two phases of different lengths, defined so that signals can be fully decoded at relays. This strategy brings full diversity but the symbol rate is not optimal. To solve this(More)