In this paper, a cooperative protocol is investigated for a multi-hop network with buffers of finite size at the relay nodes. The protocol is based on the myopic decode-and-forward coding strategy, where each node of the network cooperates with a limited number of neighboring nodes for the transmission of the signals. Each relay stores in its buffer the messages that were successfully decoded, in order to forward them through the appropriate channel links. A complete theoretical framework is investigated that models the evolution of the buffers as a state Markov chain (MC). We analyze the performance of the proposed protocol in terms of outage probability and diversity gain by using the state transition matrix and the related steady state of the MC. Our results show that the proposed protocol outperforms the conventional multi-hop relaying scheme and the system's outage probability as well as the achieved diversity order depend on the degree of cooperation among neighboring nodes. Index Terms-Cooperative networks, multi-hop relaying, myopic coding, outage probability, diversity, Markov chain.

In this paper, a partition-based scheme is investigated for multiple-input multiple-output (MIMO) fading channels assisted by an intelligent reflecting surface (IRS). In this scheme, the IRS elements are partitioned into sub-surfaces, which are periodically selected to assist the communication. Through the sequential activation of each sub-surface, an equivalent parallel channel in the time domain is produced. The proposed scheme has low implementation complexity and does not require knowledge of the channel state information. We analyze the performance of the proposed scheme in terms of outage probability and provide an expression for the diversity-multiplexing tradeoff. We show, through theoretical and numerical results, that the asymptotic performance of the considered network under the partition-based scheme can be significantly enhanced in terms of diversity gain compared to the conventional case, where a single partition is considered. Moreover, both maximum diversity and multiplexing gain can be achieved under certain conditions with respect to the number of elements in each sub-surface.

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