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This paper studies the energy efficient joint user scheduling and transmit beamforming in the downlink of a single-cell distributed antenna system. Due to the distributed nature of antenna units, traditional power consumption model cannot be applied without the backhauling power taken into account. Therefore, under the constraints of the minimum rate requirement of each user and the transmit power budget of each distributed antenna unit, we maximize the system energy efficiency through making a tradeoff between the transmitting power and the backhauling power. By employing the parametric equivalence method to deal with the fractional objective and the $$\ell _1$$ -norm relaxation method to cope with the user scheduling problem, the energy efficiency maximization is turned into a standard difference of convex program and then solved via the successive convex approximation method. Finally, the optimal sparse transmit beamforming vectors are obtained during the weighting factor iteration process, with the aim of minimizing the total power consumption while maintaining the achieved rate of each user. Extensive simulations are conducted to demonstrate the effectiveness of proposed scheme. Simulation results show that energy efficiency can benefit from not only the user scheduling but also the transmit beamforming optimization.

In this study, the energy efficient joint antenna scheduling, subcarrier assignment and power allocation are studied in an orthogonal frequency division multiple access-based distributed antenna system. A new power consumption model is proposed to the consideration of the backhauling power, which is appropriate for the architecture of distributed antenna deployment and centralised signal processing. Under the maximum transmit power constraint per distributed antenna unit and the minimum rate requirement per user, the authors formulate a mixed-integer optimisation problem to maximise the system energy efficiency. Due to the intractability, at first, a heuristic antenna scheduling strategy is proposed based on the received pilot signal power strength. Then, the remaining joint subcarrier and power allocation is equivalently turned into a parametric problem, which is solved by employing the Lagrange duality method and the Dinkelbach's algorithm. Simulation results show that the authors’ proposed joint resource allocation algorithm greatly improves the system energy efficiency.

In this paper, the energy efficient joint transmit beamforming is studied in the downlink of a single-cell multiuser distributed antenna system (DAS). A new power consumption model is defined at first, in which the backhauling power is taken into account. Then, we formulate a fractional optimization problem to maximize the system energy efficiency under the constraints of the maximum transmit power per distributed antenna unit (DAU) and the minimum rate requirement per user. The parametric equivalence method is employed to deal with the non-linear fractional objective, with the Dinkelbach's algorithm applied for searching the optimal parameter. Since the backhauling power is entangled with the structure of the beamformers, we firstly assume that each user is jointly supported by all DAUs. Moreover, due to the co-channel interference among users, the successive convex approximation method is employed. Finally, we use the weighting factor iteration to enhance the sparsity of the beamformers with the aim of minimizing the total power consumption while maintaining the achieved rate of each user. Simulation results show that our proposed joint transmit beamforming algorithm greatly improves the system energy efficiency.

Software-defined networking (SDN) and network virtualization provide a solution for the deficiency of the traditional networks such as lack of scalability and difficulty of network management. However, the solution is restricted by the speed of development, testing, and deployment. As a result, the current technology lack of rapid migration and extension could not satisfy the flexible dynamic requirements of different users to the network. To address these issues, a SDN controller platform based on the Docker engine is presented for network virtualization. The system architecture of the SDN controller based on Docker is carried out for the detailed design of virtualization solution. The flexible integration and extension of the network is realized through the virtualization of the physical resources. And the speed of deployment, the mobility and the extensibility are improved by the proposed method.

Due to type-specificity, commercially available human papillomavirus (HPV) vaccines are only effective against homologous HPV serotypes, providing limited protection. Recent studies have highlighted the role of HPV minor capsid protein (known as L2) in inducing cross-protection. The N-terminal peptides of L2 contain conserved cross-response epitopes that can induce neutralizing antibodies against heterogeneous HPVs. However, when compared with L1, these peptides have lower immunogenicity, which limits the application of these vaccines. The protein transduction domain (PTD), located in the Tat protein of human immunodeficiency virus, facilitates delivery of DNA, peptides, proteins and virus particles into cells by unknown mechanisms, and has been reported to enhance immunogenicity of several antigens. In the present study, two peptides derived from the N-terminal of HPV16L2 were chosen as model antigens and constructed a series of L2 peptide vaccines by either fusing or mixing with PTD. Subsequently their immunogenicity was evaluated. The results indicated that the L2 peptides fused with PTD show considerably enhanced humoral immunity. In particular, they increased the titer of cross-neutralizing antibodies, while L2 peptides that had only been mixed with PTD induced only small cross-protection responses. Overall, the data suggest that fusion of L2 peptides with PTD significantly enhances their cross-protection and may be a promising strategy for the development of broad-spectrum HPV prophylactic vaccines.