Groups Of Source Nodes Research Articles

Modified local link failure recovery multicast routing protocol for MANET

Multicasting in mobile ad hoc networks (MANETs) is a technique to transfer data to the group of destinations from single or group of source nodes. However, the devices in the MANETs move randomly in the network leading to regular modify the topology. The link breakages occurring due to constant changing topology reduce the performance of the network. This paper presents a multicasting routing protocol that focuses on repairing the local links in an energy efficient way. The proposed Modified Local Link Repair (MLLR) multicasting routing protocol rebuilds the link from the uplink node to the node next to the downlink node. The performance of the procedure has been compared based on throughput, packet delivery ratio and remaining energy of the network. The proposed procedure has shown improvement over the existing EOD-LLR multicasting routing protocol.

On the DoF Region for the Asymmetric MIMO Two-Way X Relay Channel

In this paper, we study the degrees of freedom (DoF) region for the multiple-input multiple-output two-way X relay channel with asymmetric antenna setting. In this channel model, there are two groups of source nodes, each group contains two source nodes, every source node in one group exchanges independent messages with every source node in another group via a common relay node, and each node has a different number of antennas. First, we derive an outer bound of the DoF region by using the cut-set theorem and the genie-message approach. Then, we obtain an inner bound of the DoF region by proposing a new transmission scheme that collectively utilizes antenna deactivation, pairwise signal alignment, cyclic signal alignment, and generalized signal alignment techniques. In the case of symmetric data exchange, our inner bound coincides with the outer bound, and thus, our proposed transmission strategy is optimal. We also obtain the optimal sum DoF for the special case, where the source nodes within a same group are equipped with the same number of antennas. This paper provides new insights for the study of more complicated relay networks.

Non-Orthogonal Multiple Access Combined With Random Linear Network Coded Cooperation

This letter considers two groups of source nodes. Each group transmits packets to its own designated destination node over single-hop links and via a cluster of relay nodes shared by both groups. In an effort to boost reliability without sacrificing throughput, a scheme is proposed, whereby packets at the relay nodes are combined using two methods; packets delivered by different groups are mixed using non-orthogonal multiple access principles, while packets originating from the same group are mixed using random linear network coding. An analytical framework that characterizes the performance of the proposed scheme is developed, compared to simulation results and benchmarked against a counterpart scheme that is based on orthogonal multiple access.

Degrees of Freedom for Complex MIMO Multiple-Way Relay Channel

The amount of diversity or the number of degrees of freedom (DOF) can be increased by multiple antennas in wireless communication systems. In this paper, we study the DOF of multiple-input multiple-output (MIMO) multiple-way relay channel. There are two groups of source nodes and several one relay node which are equipped with multiple antennas in this kind of channel. Each source node in one group exchanges independent message with the source node in the other group via the relay node. We first show the upper bound on the total DOF for this channel. Then we extend it to the complex MIMO multiple-way relay channel and present the corresponding upped bound.

Degrees of Freedom for MIMO Two-Way X Relay Channel

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 with M antennas while the relay is equipped with N antennas. We first show that the upper bound on the total DOF for this network is 2min{2M,N} and then focus on the case of N \leq 2M so that the DOF is upper bounded by the number of antennas at the relay. By applying signal alignment for network coding and joint transceiver design for interference cancellation, we show that this upper bound can be achieved when N \leq8M/5. We also show that with signal alignment only but no joint transceiver design, the upper bound is achievable when N\leq4M/3. Simulation results are provided to corroborate the theoretical results and to demonstrate the performance of the proposed scheme in the finite signal-to-noise ratio regime.