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Circular RNAs (circRNAs) are known to regulate tumorigenesis. In this study, circRNAs microarray was used to analyze the circRNA expression in lung adenocarcinoma (LUAD) tissues, and CircRNA zinc finger MYM-type containing 4(circZMYM4) was selected for further analysis. In this study, we detected circZMYM4 expression in LUAD specimens and cell lines using RT-PCR. The expression of circZMYM4 was further verified in the GEO datasets and TCGA datasets. Gain-of-function and loss-of-function experiments were used to analyze the effects of circZMYM4 on LUAD in vivo and in vitro. The relationship between miR-587 and circZMYM4 or ODAM was predicted by bioinformatics tools and confirmed using dual-luciferase reporter assays and RNA-pull down. We found that circZMYM4 was distinctly down-regulated in LUAD tissues and cell lines. Functional assays revealed that circZMYM4 overexpression suppressed LUAD cell proliferation, metastasis and suppressed apoptosis, while miR-587 overexpression could weaken these effects. Importantly, circZMYM4 upregulated ODAM expression via sponging miR-587 to suppress LUAD progression. ODAM knockdown could reverse the repressive effect of circZMYM4 overexpression on cell proliferation, migration and invasion abilities. Overall, circZMYM4 regulates the miR-587/ODAM axis to suppress LUAD progression, which may become a potential biomarker and therapeutic target.

This paper proposes a novel power control policy for a cognitive radio network as an effort to maximize throughput under the average interference power constraint. The underlined policy ensures delay-related quality of service (QoS) requirements with reduced interference to the primary user. In this work we also take into account the peak and average transmit power constraints for the secondary user. An optimization problem associated with the power control policy is formulated based on a cross-layer framework, where the queue on data link layer is serviced by the power control policy at the physical layer. A recursive algorithm under the power constraints is developed to solve for the optimal solution. It is shown that the reduction of average interference to the primary user is related closely to the QoS requirements. The analysis derives the average interference power limits to the primary user in fading channels with guaranteed QoS requirements for the secondary user. The numerical results show the effectiveness of the proposed power control policy.

The special multi-scenario of the topology in the wireless hybrid ad hoc networks is studied in this paper. A new performance evaluation link cognitive cooperation air time metric (LCCATM) and a novel cross layer multicarrier MIMO cognitive cooperation scheme are proposed. The proposed scheme integrated the attributes both of the new performance evaluation of the cooperative diversity and the attributes of the topology space. With the help of the proposed scheme, the cooperative ability of the networks is not only cognitive, but also topology aware. The average achievable sum rates and the outage probability of the networks are all examined with the cross layer constraints. The simulation results show that the proposed scheme can enhance the average rate performance and make the outage probability stable.

In this paper, we study the transmit diversity of the cooperative relay system employing multiple-input multiple-output (MIMO) technology, especially for the Alamouti space-time block codes (STBC), over slow Rayleigh fading channel. The transmit diversity gain is achieved by STBC and cooperative technology. Maximum ratio combining (MRC) and maximum likelihood detection (MLD) are applied in the destination node. Two typical relay protocols, generation relay and non-generation relay with two cooperative implementation schemes are studied in this paper. Our attention is paid to the realization and signal processing algorithms of different STBC coded cooperative systems. System bit error probabilities of these cooperative systems are provided in the simulation. Compared with the conventional non-cooperative system and Alamouti STBC scheme, the STBC coded cooperative system obtains two inherent benefits, achieving the spatial diversity offered by the relay channel and also the ability to exert the characteristics of STBC into the relay system.

In this paper, we propose a cross-layer design framework combining adaptive modulation and coding (AMC) with hybrid automatic repeat request (HARQ) based on rate-compatible low-density parity-check codes (RC-LDPC) in multiple-input multiple-output (MIMO) fading channels with estimation errors. First, we propose a new puncturing pattern for RC-LDPC codes and demonstrate that the new puncturing pattern performs similar to the random puncturing but is easier to apply. Then, we apply RC-LDPC codes with the new puncturing pattern to the cross-layer design combing AMC with ARQ over MIMO fading channels and derive the expressions for the throughput of the system. The effect of channel estimation errors on the system throughput is also investigated. Numerical results show that the joint design of AMC and ARQ based on RC-LDPC codes can achieve considerable spectral efficiency gain.

The special scenario of the topology in the cellular Ad Hoc networks is studied and a novel cross layer game knowledge sharing algorithm based on multi-hop routing Neural Fuzzy Connection Admission Controller (NFCAC) is proposed in this paper. NFCAC has been successfully applied in the control-related problems of neural networks. However, there is no discussion about the game knowledge sharing algorithm and location recognition based on NFCAC in cellular Ad Hoc networking. We firstly propose a novel multi-hop routing NFCAC which is suitable for cellular Ad Hoc networking and then propose the algorithm to integrate the functions of both multi-hop routing NFCAC and the topology space in the special scenario. The topology and power consumption of each Mobile Host (MH) can be optimized due to the minimum link occupation with the help of the algorithm. Simulation results show that the algorithm can give more control guarantee to the networks in the variable MH loads and transmission powers, and make the MHs stable to support multi-hops at the same time.

In a wireless sensor network, the sensor nodes are densely deployed for detecting in many cases. One design challenge for such a network is how to devise a good data fusion algorithm for information retrieval. Noting that the channel state information (CSI) between the cluster head and the sensor nodes will influence the received bit energy noise ratio of the sensor nodes, we propose an optimal data fusion algorithm taking into account the CSI for a one-hop clustered wireless sensor network. On the basis of the fusion algorithm, we consider the redundancy of the sensor deployment and propose a cross-layer transmission scheduling scheme. By selecting proper set of sensor nodes to transmit their local information back in turn, the scheme can prolong the lifetime of the sensor network. The numerical and simulation results show that it can get a good tradeoff between the energy efficiency and the performance.

The effect of varying effective index and random deviations of domain boundary on sum frequency generation (SFG) in quasi-phase-matching waveguides are analyzed and analytical expressions of the conversion efficiency are provided for the first time to our knowledge. By simplifying the coupled equations of SFG in waveguide, we provide analytical expressions of the conversion efficiency for the first time. Four models for variations of effective index and random errors of domains are investigated. The results demonstrate that, when effective index varying regularly along the waveguide, the normalized conversion efficiency η ^ of SFG is reduced and the curves of η ^ are no longer sinc2 function but ripple profiles, which is different from the situation in bulk crystals; with the same magnitude, random period error is of much more significance than random duty cycle error, which is similar with the case in bulk crystals.

Utilizing the advantage of concentrating energy to certain subspaces of the discrete wavelet transform (DWT), a novel peak-to-average power ratio (PAPR) reduction method for wavelet-based multicarrier modulation (WMCM) systems is proposed and presented in this paper. Both theoretical analyses and simulations are carried out to prove the feasibility of the proposed method. PAPRs are investigated by employing different thresholds. The distortions of the wavelet transform caused by the threshold are measured in terms of the mean square error (MSE). This paper also investigates the bit error rate (BER) performance of threshold controlled WMCM systems. All results given in this paper are based on a limited class of wavelets. However, this method can be adapted to WMCM system with other kinds of wavelets as well, since almost all kinds of wavelets have this similar characteristic used in the threshold control method. Therefore, we conclude that the proposed threshold method is an efficient technique for WMCM systems.

Link-adaptation scheme has been recognized as an effective way to improve the performance of energy efficiency of the IEEE 802.11a wireless local-area networks (WLANs). In this paper, we propose a new link-adaptation scheme for energy efficiency by dynamically adjusting the data transmission rate according to network load and channel quality. We first give an overview of the IEEE 802.11a orthogonal frequency domain multiplexing (OFDM) physical layer and the distributed coordination function (DCF) of the IEEE 802.11 MAC. Then, based on the theoretical goodput analysis, we proposed a new method to enhance the energy efficiency via optimizing the goodput performance using nonlinear optimization with constraints. Despite the nonlinearity in the objective function and the constraints, we show that the energy efficiency optimization can be efficiently solved for global optimality through a convex optimization technique. Our simulation results show that our link-adaptation scheme enhances the energy efficiency as well as the goodput performance of an IEEE 802.11a wireless LAN through dynamic frame length control, contention window (CW) selection, and PHY rate selection, depending on the wireless channel condition. Moreover, the proposed scheme can be extended to address some similar problems in other kinds of networks, such as congestion control, admission control, and power control.

Influence of stochastic deviations of domain boundary and varying effective index on the conversion efficiency of difference frequency mixing (DFM) in quasi-phase-matching waveguides are analyzed. By simplifying the coupled equations of DFM in waveguide according to the actual situation, we provide analytical expressions of the conversion efficiency for the first time. Four models for random errors of domains and variations of effective index are investigated. The results demonstrate that, when the effective index varies regularly along the waveguide, the normalized conversion efficiency η ˆ of DFM is dramatically reduced and the curves of η ˆ on phase mismatch are no longer sin c 2 function but ripple profiles, which is different from the situation in bulk crystals. With the same magnitude, random period error cast much larger effect on η ˆ than random duty cycle error, which is similar with the case in bulk crystals.