In opportunistic routing, each node maintains a group of candidate relays to reach a particular destination, and transmits packets to any node in this group. If a single candidate relay receives the packet, it becomes the effective relay to forward the packet further. If no candidate receives the packet, then the current sender re-transmits. If multiple candidates receive the packet, then the l...

This paper focuses on relay node scheduling method which is based on an improved discrete Markov chain. It presents a single relay node’s existing state, analyzes its access behavior, and summarizes various linear system design, according to our present balanced equations and form state transition probability, nodes are scheduled in relay network, the improved discrete time Markov chain is used...

— Providing space diversity at mobile devices such as handsets, personal digital assistants (PDA), etc is costly and problematic, due to their strict space limitation. Recent studies, however, have revealed that extraordinary diversity gain, which results in the remarkable bene ts of an increased achievable transmission code-rate and a reduced information outage probability, can be obtained fro...

In a practical deployment, mobile sensor network (MSN) suffers from a low performance due to high node mobility, time-varying wireless channel properties, and obstacles between communicating nodes. In order to tackle the problem of low network performance and provide a desired end-to-end data transfer quality, in this paper we propose a novel ad hoc routing and relaying architecture, namely RoC...

We study the degrees of freedom (DOF) of a multiple-input multiple-output (MIMO) two-way X relay channel, where there are two groups of source nodes and one relay node, each equipped with multiple antennas, and each of the two source nodes in one group exchanges independent messages with the two source nodes in the other group via the relay node. It is assumed that every source node is equipped...

This article proposes both centralized and decentralized design schemes for an analog network coding multipleinput multiple-output system with a relay node between two end nodes. The proposed centralized scheme is called the generalized iterative approach (GIA). It jointly designs the precoders and decoders at the two end nodes, and the processor at the relay to maximize the sum mutual informat...

Wireless networks that operate on batteries are imposed with energy constraints and long distance communications between nodes are not desirable. Implementing Relay Nodes (RNs) can improve network capacity and save communication energy. A two-hop relay routing scheme is considered, in which the RNs are temporarily placed and have energy constraints. This paper investigates a joint optimization ...

Adding fixed relay nodes (RNs) to wireless access networks requires additional costly infrastructure. Utilising mobile RNs, i.e., user terminals that relay signals intended for other users being the destination nodes (DNs), is an appealing cost-effective solution. However the changing node topology increases the required signalling for relay selection (RS). The signalling overhead consists of c...

In this article, we propose multiple-relay selection schemes for multiple source nodes in amplify-and-forward wireless relay networks based on the sum capacity maximization criterion. Both optimal and sub-optimal relay selection criteria are discussed, considering that sub-optimal approaches demonstrate advantages in reduced computational complexity. Using semi-definite programming convex optim...

This paper examines the information theoretic metric of outage probability for a decode-and-forward (DF) based asymmetric two-way relay transmission (i.e. the two source terminals have different target rates). We first characterize the achievable rate region of a conventional three-node network. After that the conventional three-node scenario is analyzed in terms of outage probability and the c...