A Robust Resource Allocation Scheme for Device-to-Device Communications Based on Q-Learning

One of the most effective technology for the 5G mobile communications is Device-to-device(D2D)communication which is also called terminal pass-through technology.It can directly communicate between devices under the control of a base station and does not require a base station to forward it.The advantages of applying D2D communication technology to cellular networks are:It can increase the communication system capacity,improve the system spectrum efficiency,increase the data transmission rate,and reduce the base station load.Aiming at the problem of co-channel interference between the D2D and cellular users,this paper proposes an efficient algorithm for resource allocation based on the idea of Q-learning,which creates multi-agent learners from multiple D2D users,and the system throughput is determined from the corresponding state-learning of the Q value list and the maximum Q action is obtained through dynamic power for control for D2D users.The mutual interference between the D2D users and base stations and exact channel state information is not required during the Q-learning process and symmetric data transmission mechanism is adopted.The proposed algorithm maximizes the system throughput by controlling the power of D2D users while guaranteeing the quality-of-service of the cellular users.Simulation results show that the proposed algorithm effectively improves system performance as compared with existing algorithms.

Identification of Single Nucleotide Polymorphisms and Analysis of Linkage Disequilibrium in Different Bamboo Species Using the Candidate Gene Approach

Bamboos are one of the most beautiful and useful plants on Earth.The genetic background and population structure of bamboos are well known,which helps accelerate the process of artificial domestication of bamboo.Partial sequences of six genes involved in nitrogen use efficiency in 32 different bamboo species were analyzed for occurrence of single nucleotide polymorphisms(SNPs).The nucleotide diversityθw and total nucleotide polymorphismsπT of the sequenced DNA regions was 0.05137 and 0.03332,respectively.Bothπnonsyn/πsyn and Ka/Ks values were<1.The nucleotide sequences of these six genes were inferred to be relatively conserved,and the haplotype diversity was relatively high.The results of evolutionary neutrality tests showed that the six genes were in line with neutral evolution,and that the NRT2.1 and AMT2.1 gene sequences may have experienced negative selection.An inter-SNP recombination event at the NRT2.1 gene in the all pooled sample,of all 32 bamboo species was the lowest at 0.0645,whereas the AMT gene recombination events were all>0.1.Estimation and analysis of linkage disequilibrium of five genes revealed that with the increase in nucleotide sequence length,the degree of SNP linkage disequilibrium decreased rapidly.We inferred the population genetic structure of 32 bamboo species based on the SNP loci of six genes with frequencies>18%.32 bamboo species were divided into five categories,which indicated that the combined population of all bamboo species had obvious multivariate characteristics and was heterogeneous;red(Group 1)and green(Group 2)were the main groups.

Association Analysis of the Growth of Black Poplar (Populus Nigra L.) Under Contrasting Nitrogen Levels

The European black poplar(Populus nigra L.)has been used as a germplasm resource for the breeding of new poplar varieties around the world.The identification and screening of its high nitrogen use efficiency genotypes could enable the breeding of new resource-efficient poplar varieties.The accessions were screened using MALDI-TOF MS genotyping technology for ammonium transporter(AMT)and nitrate transporters(NRT)genes against phenotypic data for seedling height and ground diameter traits,in both low and high nitrogen environments.Allele re-sequencing of seven genes related to root development was carried out using the minisequencing method.By cluster analysis,101 accessions of black poplar were divided into 4 populations,and it was concluded that Central Europe is the origin of the evolution of low-nitrogen and high-efficiency populations of European black poplar.Association study between SNP typing and seedling height and ground diameter traits showed that there were significant correlations between four SNP loci and growth traits under the contrasting N levels.We found that SNP3 and SNP4 in the PttAMT1;3 gene were significantly associated with seedling height traits,and that SNP2 and SNP7 in the PttAMT1;2 and PttAMT1;5 genes,respectively,were significantly associated with ground diameter traits.Thus,considerable allelic diversity is present within the candidate genes studied and can be utilized to develop functional markers to select for poplars with improved growth under N stress conditions.