The secure communication that multiple OFDMA-based cell-edge mobile stations (MS) can only transmit confidential messages to base station (BS) through an untrusted intermediate relay (UR) is discussed. Specifically, with the destination-based jamming (DBJ) scheme and fixed MS transmission power assumption, our focus is on the joint BS and US power allocation to maximize system sum secrecy rate....

In order to improve the energy saving performance of cooperative communication, a novel power allocation solution, named Half Transmission Power Allocation Solution (HTPAS), is proposed in this paper. In this solution, the transmission power of the relay for forwarding the packet is half of the transmission power of the source. Based on the energy efficiency analysis, HTPAS outperforms the equa...

In Ad-Hoc Networks (AHN), nodes can take on the role of a source, destination or relay. Relays are needed when source nodes wish to communicate with destination nodes that are far away. However, in acting as relays, nodes expend a significant amount of energy transmitting data across the network. Energy is a precious commodity for an AHN and the aim of nodes is to maximize their throughput and ...

Cooperative Communication, a new research area, has revealed a recent origin in the wireless networks, which combines the link-quality and the broadcasting nature of the wireless channels. It is a pure network layer scheme that can be built on top of the wireless networking equipment. Nodes in the network use a lightweight proactive source routing protocol to determine a list of intermediate no...

Cooperative diversity is a communication technique where a relay node provides signal diversity to the destination by retransmitting the signal received from the source. To find an optimal relay and maximize the resulting performance, a relay selection procedure is used with channel state information as a selection metric. In this paper, we model cooperative diversity with relay selection as a ...

For the quality of communication as multiple-input multipleoutput (MIMO), the cooperative scheme has been widely used in the wireless communication system. One of the cooperative schemes is spacetime cyclic delay diversity (STCDD). In this paper, a cooperative transmission scheme using two sources and applying STCDD is proposed. When a destination is distant from a source, the system uses two s...

This paper presents simulation of WiMAX based system under jamming. The performance of the system was found out to greatly differ with the use of different jamming signals, allowing central areas to be identified, where system development should be focused on. In addition, from the basic theory point of view, rather surprising results were also found. This work should give a clear picture of ho...

Cooperative communications, where parallel relays forward information to a destination node, can effectively improve the latency in ad hoc networks. In practice, the performance of data transmission often compromises with the variation of channel coefficient and the mobility of network nodes. The conventional fixed rate cooperative relaying cannot make the outage probability reach zero without ...

The throughput performance of a random cooperative medium access control (CoopMAC) network in the presence of shadowing is considered. The nodes are assumed to be randomly distributed according to a homogeneous twodimensional Poisson point process with constant intensity. The conditions under which a helper can improve the transmission rate between a given pair of nodes are examined. Based on t...