A simple technique to secure quantum key distribution relay networks is presented here. The paper introduces the concept of logical channels that uses a random dropout scheme. The paper also presents an enhanced protocol for key distribution in the relay networks. Previous techniques relied on creating distinct physical paths to create shares. Hence the compromise of one relay must compromise t...

We extend Shannon’s result on the capacity of channels with state information to multiple user channels. More specifically, we characterize the capacity (region) of degraded broadcast channels and physically degraded relay channels where the channel state information is causally available at the transmitters. We also obtain inner and outer bounds on the capacity region for multiple access chann...

In this study, two hop non-regenerative Multiple Input Multiple Output (MIMO) relay network is considered. Each node of the network is equipped with multiple antennas. We apply an efficient linear processing at the relay node only. We utilize Minimum Mean Square Error (MMSE) as the relay receive beamforming and PerAntenna-Signal to Leakage plus Noise Ratio (PA-SLNR) maximization criteria using ...

Dynamic spectrum access (DSA) is proposed to deal with the growing shortage of available leased spectrum for wireless communication. We investigate a subset of DSA referred to as dynamic spectrum leasing (DSL). At its core, DSL allows spectrum lease holders and cognitive radios to cooperate in an effort to leverage spatial diversity to improve channel utilization for both parties. In this resea...

In this paper, we propose novel cooperative transmission protocols for delay limited coherent fading channels consisting of N (half-duplex and singleantenna) partners and one cell site. In our work, we differentiate between the relay, cooperative broadcast (down-link), and cooperative multiple-access (up-link) channels. The proposed protocols are evaluated using Zheng-Tse diversity-multiplexing...

While a network with stationary nodes can provide large capacity in many current wireless systems, a network with mobile users suffers from severe performance degradation. This happens due to quick channel variation and its resulting protocol overheads that are especially large for multiuser multiple-input multiple-output (MIMO) systems. In this paper, we propose a relay-assisted multiuser MIMO...

Using the spatial modulation approach, where only one transmit antenna is active at a time, we propose two transmission schemes for two-way relay channel using physical layer network coding with space time coding using Coordinate Interleaved Orthogonal Designs (CIOD’s). It is shown that using two uncorrelated transmit antennas at the nodes, but using only one RF transmit chain and space-time co...

In this paper, we propose secure relaying transmission protocols using rateless codes, where a source sends encoded packets to two intended destinations via help of intermediate relays. Employing non-orthogonal multiple access, can be sent the at same time. addition, partial relay selection methods are studied enhance reliability data first and second hops. For protecting source-relay relay-des...

In IEEE 802.11, the rate of a station (STA) is dynamically determined by link adaptation. Low-rate STAs tend to hog more channel time than high-rate STAs due to fair characteristics of carrier sense multiple access/collision avoidance, leading to overall throughput degradation. It can be improved by limiting the transmission opportunities of low-rate STAs by backoff parameters. This, however, m...