Multiple Parallel Transmission Research Articles

An Energy-Efficient Scheduling Algorithm With SIC and Power Control in WSNs

In large-scale wireless sensor networks (WSNs), spectrum efficiency and energy consumption are two challengeable problems to be solved due to the increasing traffic requirement and its limited energy. Successive interference cancellation (SIC) technology, which supports multiple parallel transmissions, gives an opportunity to improve the efficiency of data collection. However, those classical schemes suffer from high energy consumption, which presents a severe challenge to energy-constrained WSNs. To improve the transmission and energy efficiency of WSNs, we study an energy-efficient scheduling algorithm joint with SIC and power control in this paper. We first develop a non-uniform M-Level scheduling model to identify the beneficial opportunities and guarantee the transmission quality of SIC concurrency. Then, we formulate an energy efficiency maximization scheduling (EEMS) utility and further transform it into a combinatorial optimization problem. To reduce the computational complexity and obtain meaningful insights, two low-complexity optimization algorithms are proposed from the perspective of SIC scheduling and power control, respectively. Finally, extensive results demonstrate that the SIC scheduling design enables our proposed algorithm to achieve 51% higher throughput than the algorithm without SIC. Moreover, the energy efficiency of our proposed algorithm is improved by 37% compared with the existing algorithms, which indicates that our algorithm can search for the optimal configuration of SIC-concurrent transmissions and better manage the concurrent transmission power.

Reliable uplink transmissions for NOMA-based Industrial Wireless Networks with guaranteed real-time performance

Reliability is vital for ultra-reliability low-latency transmission applications in Industrial Wireless Networks (IWNs). The power-domain Non-Orthogonal Multiple Access (NOMA) technology can support multiple parallel transmissions, and has been thought of as one of the most powerful candidate radio access technology for the next-generation IWNs. However, it suffers from low transmission reliability because of the high interferences caused by parallel transmissions in power-domain NOMA. In this paper, given the real-time performance requirements, we consider a single-hop network supporting 2-Successive Interference Cancellation, and study how to maximize the reliabilities of uplink transmissions by the joint user pairing and power allocation. We show that the problem is solvable in polynomial time by an optimal algorithm with complexity of O(nlogn), where n is the number of users. The performance evaluations reveal that the transmission reliabilities will increase exponentially with the linear degradation of the guaranteed real-time performance.

Optical frequency comb-based multichannel parallel continuous-variable quantum key distribution.

Continuous-variable quantum key distribution (CVQKD) provides an approach for secure communication in optical fiber communication systems. However, its practical implementation has been hindered by low secret key bit rates that are usually limited to several bits/s to hundreds of kbits/s at distances of more than 25 kilometers. In this paper, we use a pair of optical frequency combs (OFCs) for both multiple parallel transmission and coherent reception, which assign multiple sub-channels involving multiple independent secret keys in a single fiber to increase the key bit rate. The first and last sub-channels are selected for propagating phase references to compensate the phase offset between two free-running combs. We analyze possible excess noise caused by dispersive walk-off in the transmission, imperfect phase compensation in the reception and photon leakage from the phase references. Compared to the previous single-channel CVQKD method, simulation results show more than a factor of 20 increase in the secret key rate at a transmission distance of 35 km and the number of comb lines of 35.

MLOPS: A SIC-Based Minimum Frame Length With Optimized Power Scheduling for UANs

Due to the large propagation delay and scarce spectrum resource of the underwater wireless acoustic channels, it is essential to design efficient and reliable multiuser scheduling scheme for underwater network communication systems. The successive interference cancellation (SIC) technology that supports multiple parallel transmissions can improve spectrum efficiency, which is vital for the underwater acoustic networks (UANs). The SIC technology has been widely studied in the underwater network communication systems. However, there is no appropriate technology solving the link scheduling problem in the SIC-based UANs. In this paper, we propose a link-scheduling model for SIC-based UANs and formulate the problem of minimizing the transmission delay and overall network power consumption by combining transmitters scheduling and power allocating. We also present a polynomial-time algorithm named UMLOPS with the complexity of O(n) for unified traffic load, and for weighted traffic load, we present a universal algorithm named WMLOPS with the complexity of O(n 3 ), where n denotes the number of source nodes. The extensive simulation results reveal that both scheduling frame length and aggregate power consumption of MLOPS significantly outperform those of the existing time-division multiple access protocols in underwater sensor equipped aquatic swarm architecture networks.

Detection of Multiple Parallel Transmission Outbreak of Streptococcus suis Human Infection by Use of Genome Epidemiology, China, 2005.

Streptococcus suis sequence type 7 emerged and caused 2 of the largest human infection outbreaks in China in 1998 and 2005. To determine the major risk factors and source of the infections, we analyzed whole genomes of 95 outbreak-associated isolates, identified 160 single nucleotide polymorphisms, and classified them into 6 clades. Molecular clock analysis revealed that clade 1 (responsible for the 1998 outbreak) emerged in October 1997. Clades 2–6 (responsible for the 2005 outbreak) emerged separately during February 2002–August 2004. A total of 41 lineages of S. suis emerged by the end of 2004 and rapidly expanded to 68 genome types through single base mutations when the outbreak occurred in June 2005. We identified 32 identical isolates and classified them into 8 groups, which were distributed in a large geographic area with no transmission link. These findings suggest that persons were infected in parallel in respective geographic sites.

MIMO capacities and outage probabilities in spatially multiplexed optical transport systems

With wavelength-division multiplexing (WDM) rapidly nearing its scalability limits, space-division multiplexing (SDM) seems the only option to further scale the capacity of optical transport networks. In order for SDM systems to continue the WDM trend of reducing energy and cost per bit with system capacity, integration will be key to SDM. Since integration is likely to introduce non-negligible crosstalk between multiple parallel transmission paths, multiple-input multiple output (MIMO) signal processing techniques will have to be used. In this paper, we discuss MIMO capacities in optical SDM systems, including related outage considerations which are an important part in the design of such systems. In order to achieve the low-outage standards required for optical transport networks, SDM transponders should be capable of individually addressing, and preferably MIMO processing all modes supported by the optical SDM waveguide. We then discuss the effect of distributed optical noise in MIMO SDM systems and focus on the impact of mode-dependent loss (MDL) on system capacity and system outage. Through extensive numerical simulations, we extract scaling rules for mode-average and mode-dependent loss and show that MIMO SDM systems composed of up to 128 segments and supporting up to 128 modes can tolerate up to 1 dB of per-segment MDL at 90% of the system's full capacity at an outage probability of 10(-4).

On Adversarial Games in Dynamic Spectrum Access Networking based Covert Timing Channels?

In this paper, we study tactical covert timing networks with dynamic spectrum access capability amidst adversaries. We present a two-tier game framework to model the attackdefense scenario. There are very few studies available in the literature on covert timing channels with multiple parallel transmissions. This paper presents a new paradigm combining the time diversity provided by covert timing channels and frequency diversity provided by dynamic spectrum switching, to combat jamming. The dynamic sensing of different spectrum bands and subsequent jamming by the attacker, and the camouflaging defense by the covert network are modeled as a two-tier game. We present a dynamic minimax camouflaging strategy for the covert network and sensing and jamming strategies for the attacker. We compare the performance of our proposed equilibrium strategies with that of other well known strategies and demonstrate the effectiveness of our proposed solution. We use theoretical analysis, simulations and testbed experiments to illustrate our ideas.

TDMA with multiple parallel transmission using a directional antenna

TDMA with multiple parallel transmission using a directional antenna

Characterization of Multiple Parallel Transmission Lines Using Time Domain Reflectometry

Two methods of using time domain reflectometry for the characterization of a system of multiple parallel transmission lines are described. The two methods are the reflection method and the direct method. The selection of a method depends on the accuracy required and the property of the system of transmission lines to be measured: [Y0], [Z0], [C], or [L].

Comment: Time-discrete networks

The letter is concerned with time-discrete networks characterised by difference relations. It is shown that a time-discrete network can be defined as an interconnection of lossless transmission lines and multiple parallel transmission lines, resistors and voltage- and current-sequence sources. An approximation of LC components by means of lossless transmission lines is equivalent to the choice of a ‘trapezoidal’ rule of a numerical integration.

Matched-termination network for multiple parallel transmission lines

A matched-termination network for multiple parallel transmission lines is capable of absorbing all the possible TEM propagation modes without reflection. A general expression is presented for such a network when the transmission lines are lossless. If, in addition, the propagation velocities are all equal, a network can be designed by inspection.

Time-domain analysis of multiple parallel transmission lines by means of equivalent circuits

Thévénin's equivalent circuit for a single transmission line is well known. The letter presents an application of Thévénin's equivalent circuit for multiple parallel transmission lines to the time-domain analysis of wave propagation over such lines. For purposes of illustration, a system of two coupled transmission lines is treated.