This research analyzed the impact of Wi-Fi received signal strength indication (RSSI) on power consumption of smart phones under different network environments. It was found that bad signal may lead to decrease in network link speed but increase in power consumption; whereas good signal contributed to rapid transmission and low power consumption. To reduce the power consumption and prolong the battery life, through combination with the original IEEE 802.11 PS mechanism, an optimization mechanism based on RSSI-awareness was proposed which aggregated network packets and delayed transmission. In essence, the proposed mechanism functioned through decreasing the number of mode switches of Wi-Fi component and extending the time of Wi-Fi stay in the Power-Save (PS) mode. Specifically, the signal strength was divided into three levels, including "good", "weak" or "bad". The decision tree was used to choose the best transmission method (Normal / Lineral / Exporational Transmission) according to previous and current signal strength. Algorithms were introduced to select the best split of decision tree for partitioning specific records into smaller subsets. Finally, the proposed mechanism was performed on the TI pandaboard platform. The results indicated that the proposed mechanism was practical and able to reduce the power consumption of smartphones in an effective manner.

In this era of modern technology wireless control system is a most used method to control electrical or electronic devices and/or monitoring from a distant part. It is very easier and cost effective to implement a wireless system. Because there are barriers in implementing wired system. That is why wireless system is much effective than wired. But the wireless system has also some problems or deficits. One of them is signal loss during the transmission due to various causes like surrounding environmental reason and others. If transmitted signal is lost the receiver will remain completely blind as it is not receiving the signal. Another one can be the receiver is unable to receive signal due to the technical fault of receiver end whether the transmitted signal is stable. That is why an acknowledgement system is necessary to determine whether the receiver is receiving the transmitted signal or not. The developed system is an effective and low cost system with nRF24L01P transceiver module and Arduino Uno to determine that the receiver is working accordingly or not or is there any technical fault.

This paper explores the effect that transmission power has on the performance of a Mobile Ad hoc Network (MANET). The goal of this research is to determine if the lifetime of the network can be prolongated by using less energy and thus, resulting in a more energy efficient ‘greener’ architecture. A total of 72 unique simulations are conducted of various configurations covering a large variety of possible scenarios: we examined configurations with a different number of nodes, number of traffic flows, mobility model, transmission power and geographical areas. Results show that there is an optimal transmission power, which enhances greater network performance: moreover, this optimal transmission setting makes the network more energy efficient in terms of depletion of the finite energy sources of the nodes. Our overall findings also confirm that higher transmission power results in less energy consumption.

In this paper, relaying technique and non-orthogonal multiple access (NOMA) are adopted to improve performance of visible light communication (VLC) system. Due to the adoption of relay terminal, the link reliability and communication coverage of VLC system are boosted. Besides, the utilization of NOMA can greatly increase spectral efficiency and support massive connectivity. So, a cooperative NOMA-based DCO-OFDM VLC system is proposed. All the optical transmission links use DCO-OFDM to accomplish information transmission. The relay terminal in the proposed system not only forwards the source signal but also sends its own signal simultaneously. The signals over the links between relay and two users are superposed based on NOMA. Under different cases, the total throughput is analyzed and the optimal power allocation factor is obtained. In addition, the OMA-based system is taken as the benchmark system. The simulation results further verify the theoretical results and the superiority that the proposed system has.

In order to improve the fault-tolerant ability under parameter perturbation, the robust power control problem based on channel uncertainty is studied. In this paper, the robust optimization theory and stochastic optimization theory commonly used to deal with uncertain parameters are deeply analyzed, and the mathematical significance, application scenarios, advantages and disadvantages of the two optimization theories are summarized. A comprehensive solution for bounded uncertainty and probabilistic constraints is proposed. On the one hand, the scheme guarantees the rights and interests of the primary user under the worst error, on the other hand, the secondary user is satisfied with a certain interrupt probability under the condition of system robustness. In this paper, the main user interference temperature and the secondary user probability SINR are taken as the constraint conditions, the maximum throughput of the system is transformed into a convex optimization form, and the Lagrange dual (LD, Lagrange Duality) principle is used to solve the problem. The results show that the double optimization solution is a compromise between probabilistic constraint algorithm, Worst-case algorithm and non-robust algorithm, which not only fully protects the rights and interests of the primary user, but also takes into account the robustness. At the same time, the conservatism of the bounded uncertain design method is avoided.

When studying the power control problem of cognitive radio based on non-cooperative game theory, most scholars pay more attention to constraints such as interference, signal-to-noise ratio of secondary users, primary user interference threshold and so on. Optimization objectives focus on system throughput, system energy consumption, convergence rate, etc. The fairness problem caused by secondary users in order to increase system throughput is ignored, and the research on whether all the secondary users participate in the communication meets the communication conditions is in blank state. Based on the fairness problem, an automatic power control game algorithm based on cost function is proposed in this paper. When the cost function is designed, the influence of distance on channel gain is fully considered, and the penalty mechanism is introduced by adjusting the weight adaptively. The interference between users is reduced, and the near-far effect caused by different user location is effectively overcome. In order to solve the problem of whether the secondary users meet the communication conditions, a sub-user selection strategy is proposed to accurately control the secondary users who participate in the communication, thus avoiding the hidden danger to the stability of the system caused by the users who do not meet the communication conditions. The necessity and practical value of the user selection strategy are verified by simulation. At the same time, the performance of the proposed algorithm in convergence speed and energy saving is also highlighted.

When the channel fading is assumed to be fast fading and the transient variation of the channel gain is considered, the signal-to-interference noise ratio (SINR, Signal to Interference plus Noise Ratio) of the secondary user changes with the channel gain. This will cause some secondary users to fail to get the SINR, required for normal communication if the secondary user transmit power is enhanced, although it meets the secondary user communication requirements, at the same time, the interference to the primary user exceeds the interference threshold. Affects the normal communication of the primary user. In order to solve this problem, a robust power control algorithm based on probabilistic constraints is proposed. In this paper, the average SINR model is transformed into the uncertain distribution model by introducing the uncertain parameters satisfying the exponential distribution. In this paper, the SINR probability density functions of primary and secondary users are given, and the probabilistic constraints are transformed into deterministic constraints. In order to solve the secondary user transmit power, the interference temperature of the primary user is taken as the constraint condition, and the complete iterative algorithm is used to realize the fast convergence of the secondary user transmit power. Since the protection of the primary user will lead to the damage of the interests of some secondary users, this chapter introduces the admission control, according to the highest degree of dissatisfaction first eliminate the mode of the sub-users who do not meet the requirements of communication to implement admission control. The number of secondary users meeting the communication condition in the system is increased. The simulation results show that the algorithm can quickly identify the secondary users who do not meet the communication conditions, and avoid the excessive elimination of the secondary users, increase the number of secondary users who can communicate normally, and increase the total throughput of the system.

According to the requirements of this design, a new type of lens was designed. The uniformity of illumination on the two walls was 0.83 and 0.64 respectively, which solved the problem that one wall surface was basically no light when the traditional wall washer illuminates the two walls. The light source is selected from the CREE XM-L2 type lamp bead with a power of 10 W. In this paper, the cutting method is used as the design idea of the free-form optical system, and the secondary optical design of the LED floodlight optical system is carried out.

The combination of Feng shui and lighting can create a yin and yang balanced light space, which will become the trend of lighting design in the new era. The suitable lighting environment is beneficial to the physical and mental health of the occupants. By collating and analyzing the theoretical system of Feng Shui, this paper maps the 1931 chromaticity diagram and the five elements, and then selects the appropriate light source to adjust the energy of the human body and the surrounding environment. The combination of traditional Chinese martial arts and modern lighting is a new kind of interdisciplinary research, which is of great significance for the harmonious between human and light.

In order to solve the vicious circle of negative emotions caused by stress spreading in the family. This paper designs a lighting control system that reflects the user’s emotions in real time to assist users in managing emotions. The system establishes an emotion-color conversion model based on color psychology. Based on the Face++ face recognition cloud platform, the Raspberry Pi and Arduino form the hardware core for the overall design, hardware selection and software programming of the lighting control system. The system collects the user’s facial image and uploads the image to the cloud platform, and then the cloud platform performs face recognition on the image. The recognized face parameters are returned to the system. Then according to the emotion-color conversion model, the face parameters are converted into light parameters. Finally, the system transforms the light according to the light parameters, so that it realizes the effect of transforming the light color according to the facial expression of the user, and plays a role in supporting the management of emotions.