Design of Healthcare Lighting in Medical Centers Based on Power Carrier Communication

Hospital lighting is an essential embodiment of hospital modernization. With the increasingly significant role of the medical environment in the medical process, both the lighting requirements of various treatments in the hospital and the response of patients to the lighting environment should be considered in the design. Avoid the discomfort and disgust of patients caused by improper lighting layout or illumination selection. To meet the physiological and psychological needs of patients and medical personnel, the light environment of medical buildings is no longer limited to meeting the requirements of illumination. Still, it focuses on strengthening its comfort and creating a harmonious and comfortable medical environment as well as possible. Starting from the lighting design of health treatments in medical centers and aiming at the light environment regulation requirements of medical buildings based on power carrier technology (PLCC), a lighting control system with easy implementation and simple operation is developed in this paper.


INTRoDUCTIoN
The effective use of medical lighting control systems not only plays a positive role in the health of medical staff but also helps to achieve the effect of diagnosis and treatment, patient rehabilitation, and the improvement of doctor-patient relationships.At the same time, it is also conducive to hospital operation management and cost control (Chen et al., 2021).The medical lighting control systemmedical lighting control system design should meet the functional requirements and use purposes.Practicioners should not only consider the impact of lighting environment on people, reasonably designed illumination, color temperature, color rendering, and glare control, but also consider the energy consumption specification of lighting and effectively configure lighting lamps and control methods (Yu et al., 2017).Natural lighting and artificial lighting can improve patients' comfort and are essential factors in improving the safety and efficiency of medical facilities.Relaxing in the environment and receiving good natural or artificial light will help improve people's health and resistance and help them recover from diseases faster (Xu et al., 2019).By ensuring sufficient lighting for safe passage in the building, high-quality lighting in diagnosis, sufficient lighting for treatment and rehabilitation areas, and comfortable lighting in wards and lounges, the psychological pressure of patients can be alleviated to the greatest extent, errors can be reduced, and the quality of life and working conditions of patients and employees can be improved (Tian et al., 2019).In addition, by designing lamps that are easy to maintain and clean, practicioners can reduce energy consumption and control disease infection (Wang & Li, 2021).The medical lighting control system is crucial for hospital construction and management.However, in hospital construction and actual operation, the attention to medical lighting control systems is still relatively low.The first reason is that the hospital construction side has less research on hospital lighting and lacks in-depth understanding of the role of lighting; secondly, there is a lack of understanding of the requirements of hospital lighting in the field of lighting engineering, and there is a lack of reasonable and effective lighting control systems.
The lighting control system of health treatment in medical centers can save energy and improve the comfort of doctors and patients.This problem can be solved by using power line carrier communication technology.The cost of power line carrier communication infrastructure is low, so it has broad practicability with the advantages of infrastructure (Jignesh et al., 2017).However, like all other technologies, power line carrier communication also faces its technical challenges.As the communication medium of this technology, the communication channel of power line is usually complex.The performance of power line communication is greatly affected by noise, so it is necessary to analyze the channel characteristics of power line carrier communication.Based on the power carrier communication technology, this paper constructs the medical center's health treatment lighting control design system.Its innovations include: 1.This paper introduces and analyzes the importance of an appropriate lighting environment for medical treatment and the research status of lighting control systems.This paper points out the urgent demand for lighting control in today's medical environment and the advantages of power carrier communication technology, and it further puts forward some understandings of medical lighting.2. This paper studies the noise model of the power line carrier communication channel, including noise generation and the mathematical model.The noise interference of carrier communication is analyzed in detail.3. The hardware design adopts the top-down modular design method, which makes the circuit module easy to modify and highly utilizable.The hardware core chip adopts domestic chip, and domestic technology accounts for a large proportion of the scheme.
According to the contents involved in this paper and the needs of the article structure, this paper will be divided into five chapters.The contents of each chapter are as follows: The first chapter is the introduction.This part briefly introduces the research background, main content, and innovation of this paper.The second chapter is the related work.This chapter describes the research status of the research topic at home and abroad, and puts forward this paper's research work and methods.The third chapter is divided into two parts.The first part summarizes and puts forward the intelligent lighting control system of medical centers while defining the relevant concepts.In the next part, the lighting system design based on power carrier communication is constructed based on power carrier communication technology.The fourth chapter carries out a large number of experimental analyses to explore the system's performance proposed in this paper.The fifth chapter is the summary and prospect.This chapter summarizes the research results of this paper; the shortcomings of this paper and the research direction of future work are given.Li et al. (2018) believe that the hospital's lighting mainly meets the needs of medical diagnosis, rescue treatment, and patients' recovery and rest.Christian et al. (2019) believe that the light environment design is mainly functional lighting, biased towards technical indicators such as illuminance, color temperature, and glare.Often, the lighting mode is singular, the light source's colour temperature is too high, there is glare, and there is a lack of health treatment lighting for psychological and physiological regulation.Lee and Chiang (2018) studied the application of a healthy lighting environment and the impact of the light environment in living space on the quality of life of the elderly and applied health healing lighting to practical medical projects, covering three aspects: visual function, physiological regulation, and emotional intervention.The research mechanism of Kageyama et al. (2019) is to adjust the light environment in combination with emotional needs, to affect the physiological rhythm through the biological clock, and to promote the healing of human health.Jiang et al. (2020) believe that power line carrier communication technology is widely used in lighting system control.Power line carrier communication is developing rapidly in Europe (Germany, Sweden, Finland, and other countries) (Ming et al., 2019).

ReLATeD woRK
The German government has formulated power line communication rules (specifying the minimum emission and noise level).It has developed a technology called "power grid online", which enables users to access the Internet through power lines with only a special modem.At present, Kyushu Electric Power is planning the power line Internet.It plans to build a high-speed network and provide internet services by erecting cables on power poles.In China, in the 1940s, carrier machines produced by the company ran in the northeast to communicate long-distance scheduling (Chawla & Kansal, 2020).Shi et al. (2020) believe that after decades of development, it has a considerable scale and level and has developed a series of products for intelligent community, automatic meter reading, remote data transmission, home automation, and other fields; but most of them use chips developed abroad.Because these chips are made according to the characteristics of the foreign power grid environment, the effect is not ideal, and China's technology in this field is not mature.The development of power line carrier technology and application has been mentioned in the power communication plan of the eleventh five-year, which points out the way for power line carrier communication (Chen et al., 2017).Familua and Ling (2018) believe that with the increasing improvement of power carrier communication-related technologies and the large-scale integration of digital circuits, the transmission distance and reliability of carrier communication have been greatly improved.This technology has been widely used now.Through transformer routing exchange, multi-directional communication on power lines can be realized (Familua & Ling, 2018).Wang (2021) believes this technology has broad development prospects.The development status at home and abroad also shows that power line carrier communication will bring another information revolution to lighting control systems as an emerging technology.
Based on the in-depth study of power carrier communication technology, this paper analyzes the principle technology of this technology.The lighting design system of medical centers based on power carrier communication is constructed.This paper makes an in-depth investigation from the following aspects: the research status of lighting control systems, the research of the power line carrier communication channel, the research of signal modulation, and the design of software and hardware of the system.The power line carrier communication is power line, so the research on channel is essential and must be considered.This paper studies the noise classification and noise model of the power line carrier communication channel and designs the system.Finally, the system passes the test, and the communication is stable and reliable.It can effectively control the common lighting system in the hospital.The research of this paper can provide some reference for the research of lighting system control or related aspects.

MeTHoDoLoGy Intelligent Lighting Control System for Medical Centers
Lighting is an essential link in the development of human history.Edison invented the electric light, which illuminated the whole world.In addition, lighting devices also account for a large proportion of energy consumption.According to the data, the Three Gorges Hydropower Station generated 84 billion kwh per year in 2004, compared with 218 billion kwh for lighting, equivalent to three hydropower plants in the Three Gorges (Ramadan et al., 2022).At the same time, in the use process, the management of lamps is not scientific enough.This situation leads to the unnecessary use of many bulbs, which leads to the waste of energy and affects the real-time monitoring of the corresponding lamp group.Therefore, people have been looking for appropriate and reasonable management methods.The Dynalite distributed intelligent lighting control system developed by Bangqi, Australia is characterized by modular structure and distributed control; modules with independent functions of various components are connected by a twisted pair data communication bus (br48_ 5) to form a dynet control network.Dynamite distributed intelligent lighting control system distributes the control functions to each module in the system (such as the dimming module, scene switching control panel, and smart probe).Each functional module communicates with theeach other directly through the network bus.When a module in the system fails, it will not affect other modules and has high reliability; the ABB intelligent lighting system adopts two-core wire control, and the EIB bus is used to connect each input, output, and system element in the system.The load cable with large section is directly connected to lighting lamps or other electrical loads from the output end of the unit without going through an intelligent switch.Domestic research on intelligent lighting control technology is also relatively rapid, such as intelligent residential central control system, IHCC, "truth, goodness and beauty" brand intelligent lighting control switch, etc.Currently, the existing problems are that the popularity of products is low, the price is high, and the compatibility of various products is not enough, affecting the promotion and use of products.Especially in medical centers with high requirements for light control, improper lighting layout or illumination selection will cause discomfort and disgust inof patients, which is challenging to play a role in healing comfort.
As most know, sub-health is a global problem.A global survey by the World Health Organization shows that in the world, only 5% of the healthy people are healthy, doctors diagnose 20%, and 75% are sub-healthy (Chen et al., 2019).Sub-health is neither a disease nor a critical point of health.It is a low-level health state between health and disease.However, mental vitality, adaptability, and reaction ability will be reduced.If not solved in time, it may lead to mental illness.The most important crucial role for humans is vision, which enables us to distinguish brightness, shape, color, picture, perceived information, and contrast (Sheikh et al., 2021).In addition, light also has biological effects, with effects on hormones, alertness, attention, fatigue, and the biological clock and circadian rhythm.The importance of people-centered lighting design is self-evident, but it is lacking in the domestic lighting design industry.
The intelligent lighting control system includes centralized management controller, trunk line, control signal interface, etc. and carries out the same control for each lighting control area.Its subcontrol system includes various dimming modules, control panels, dynamic illuminance detectors, dynamic detectors, mobile detectors, and other components and controls each controlled area differently.Among them, the central control system and the sub-control system are connected through control signal interfaces and other components to realize the transmission of lighting control data.Figure 1 shows the basic structure of the intelligent control system of the medical center.
An intelligent lighting control system can be divided into multiple groups of light modules; each module has corresponding control equipment, and the related brightness can be adjusted by adjusting the illuminance to realize the automatic control of all bulbs.The communication connection between computer and lamps is realized by bus; coordinate the communication between lighting equipment and control system.Figure 2 shows the intelligent lighting control subsystem.This paper believes that to obtain a better lighting control effect, it is necessary to control the lamp group through power line carrier communication.Still, the environment on the power line is

Design of Lighting System Based on Power Carrier Communication
Because the carrier communication infrastructure of power line is cheap, it has a wide range of applications.However, like any other technology, power line carrier communication will also encounter technical problems.Power line is the communication medium of this technology, and its communication channel is often complex.The communication performance of power line is mainly affected by interference factors, so it is necessary to analyze its channel characteristics.
There are many noises in power lines.These noises mainly come from various electronic devices on the wire, such as the thermal noise of free electrons in resistors during thermal movement and the noise caused by carrier fluctuations.In the communication system, resistance device noise, antenna noise, and receiver noise are equivalent to thermal noise.Through test and theoretical analysis, it is found that when the resistance value is R , the unilateral power spectrum density of the resistance is: This frequency range is extensive, including millimeter waves in all bands.Researchers usually call this noise white noise.Therefore, the power spectral density of thermal noise in a communication system can be expressed as: The thermal noise of the resistor can also be expressed in the form of noise current source or noise voltage source.According to the central limit theorem, the thermal noise voltage follows Gaussian distribution, the mean value is zero, and the one-dimensional probability density function is: It can be seen from the above results that the fluctuating noise, such as thermal noise and shot noise, belongs to Gaussian noise, and the power spectral density remains unchanged in a large band.Therefore, this noise is generally regarded as close to Gaussian white noise.The bidirectional spectral density of Gaussian white noise is: Its autocorrelation function is: This formula shows that the value of zero mean Gaussian white noise at any two different times is irrelevant, so it is statistically independent.According to the Shannong formula, under the condition of white noise interference, the channel capacity of the communication system is: This means that given the capacity of C channel, it can improve the bandwidth of B channel and reduce the signal-to-noise ratio S N / ; at the same time, it can improve the channel bandwidth and reduce the signal-to-noise ratio.In other words, by increasing the channel bandwidth, the information transmission rate in the channel can be achieved under a given signal-to-noise ratio.
The core of the whole system is the carrier communication module.This chapter first introduces the selection and comparison of carrier modulation chips, then introduces the internal functional modules and working principle of direct sequence spread spectrum carrier modulation chip and teaches the design, calculation, device selection, and software design flow of its peripheral circuit.Then, the implementation process of the whole system is described from the perspective of system.
In the parameter setting part of the chip, when setting (reading) or writing the line, MCU sends the signal to the CS end of the line, sends the setclk to the line, and sends the 8-bit control word to the line terminal serial under the action of the synchronization pulse, that is, from high to low, provides 6-bit (A5 ~ A0) address in turn, and then gives 8-bit data.Different working conditions can be obtained by setting working conditions; for example, the size of communication speed and capture threshold.The operation condition registers S1 and S0 use these two bits to determine the communication speed and to select the values of three communication speeds.The communication rate is set as Table 1.
In practical application, different acquisition thresholds can be selected according to the actual communication environment to achieve a better communication effect.When setting the capture threshold, pay special attention to match with the communication rate value; otherwise, the capture threshold will be too large to be synchronized.As shown in Table 2, the capture threshold setting values are displayed.When D4 to do is 11001 (19 h), the capture threshold is 2180.The communication cycle number obtained by taking 10 as s1so is 4, and the communication effect is ideal.
In the input channel design part, the main crystal oscillator of the carrier module is 16 m, the carrier frequency is 250 kHz, the bandwidth is 100 kHz, 4-cycle phase modulation and 1kbps data rate.The input channel includes coupling transformer, one-stage bandpass filter, front-end amplifier, on-chip one-stage operational amplifier, on-chip two-stage operational amplifier, on-chip twostage operational amplifier (without on-chip three-stage operational amplifier), and zero crossing comparator.The function of the input channel is to couple the signals on the power line and restore them to the output waveform after amplification, filtering, and other processing.The reference standard of signal restoration should be consistent with its output signal.After the signal is transmitted through the coupling circuit, it first passes through amplitude limiting to avoid too high of a signal amplitude, then passes through the band-pass filter to filter out the out-of-band clutter.It should not only filter out the out-of-band clutter, but also ensure the impedance matching between the front and rear stages to achieve smooth signal transmission.The output channel comprises the OC gate output of the 24th pin, the power amplifier, and the coupling transformer.The function of the power amplifier is to convert the high-voltage open drain output of the 24th pin to the success rate output.
To improve the transmission power, a quasi-complementary class B push-pull circuit with a single power supply with an output stage of a special-shaped composite tube is adopted.
In the software design part of carrier module, carrier modulation and demodulation chip and single chip microcomputer control chip AT89C2051 form carrier module.Taking the single chip microcomputer as the control core, the chip's working environment and working mode are controlled.The direct sequence spread spectrum technology is mainly used to realize the modulation and demodulation of the signal on the power line and complete the signal transmission on the power line.This chapter mainly completes the software and hardware design of power line carrier module lighting system.The hardware design adopts the top-down modular design method, which makes the circuit module easy to modify and highly utilizable.The hardware core chip adopts domestic chip, and domestic technology accounts for a large proportion of the scheme.Based on the hardware design, according to the transceiver timing of the protocol, the interrupt processing method is used to complete the design of the data transceiver software.

ReSULT ANALySIS AND DISCUSSIoN
This paper tests the host control module.The RXD and TXD pins of the host AT89C51RC are used as RS232 interfaces, and the host and PC are connected through RS232 interfaces.Install the general RS232 debugging program tserial on the PC.Various control signals the host generates (not packaged as data frames) can display hexadecimal data strings on the PC.Check these hexadecimal data strings to determine whether the host is working normally.After testing, the host AT89C51RC chip performs well and can generate control signals under various circumstances.
This paper tests the terminal control module.The pins of terminal chips P30 and P31 are made into the RS232 interface, which connects the terminal and Po through the RS232 interface.Modify the terminal program, shield the functions related to carrier communication, and add the serial communication function.Input the control signal to PL3105 through tserial through RS232 (encapsulated after the data frame), observe the lamps controlled by the terminal node and the feedback data of the received tserial window to judge whether the terminal node works normally.The test results show that the terminal chip can work normally, complete the control of the lamp under various conditions, and generate the analog feedback signal consistent with the expectation.
On the basis of hardware and software, the corresponding communication test is carried out.Carrier communication is the core part of the whole control system.Each node should use a carrier communication module to communicate with other nodes.The carrier communication module is tested in the precision metering room.The electrical appliances used in the laboratory include two air conditioners, two temperature regulating welding tables, three printers, 17 PCs, and 30 fluorescent lamps.Outside the building, there are all kinds of electrical appliances everywhere.The test node adopts the node based on optical control terminal, using P3 0 and PF3 1 as RS232; the test node is connected with PC by RS232.PCI will give the received information to PC2 and then transfer it to test bench 2. The information received by test bench 2 will be transmitted to test bench 2, and the information received by test bench 1 will be transmitted to PCI.PCI will confirm the received information.If confirmed that it meets the requirements, it will be regarded as this communication; otherwise it will be regarded as a task.In order to verify the operation status of the carrier on various power lines, a typical period of time is selected for the test.To increase reliability, three sets of the same tests are conducted in each selected period, and 1000 communications are required for each test.The effect of the test is shown in Table 4 and Figures 3 through 6. Collect communication data under different conditions as follows: Compare the experimental data with the average accuracy data of traditional communication, and the results are shown in Figure 7.
This chapter conducts several experiments to verify the performance of the power carrier communication medical lighting control system constructed in this paper.The experimental results show that the overall communication success rate of the carrier communication system in this paper is more than 98%, which can be achieved in both software and hardware and hardware aspects, which is 6.3% higher than the traditional control method.The model in this paper can better overcome the shortcomings of conventional methods and can effectively control medical buildings' light environment adjustment requirements.

CoNCLUSIoN
Lighting is a major symbol of the development of modern hospitals.In medical activities, due to the increasing impact of medical conditions, the lighting design of buildings should consider not only different lighting needs but also patients' responses to lighting.To meet the physiological and spiritual needs of patients and medical workers, the lighting environment of the hospital building is not limited to meeting the illumination standard; pay attention to improving its comfort, and try to create a harmonious and comfortable medical atmosphere.According to the design of health treatment lighting in medical centers, combined with the lighting regulation requirements of medical buildings, and based on PLCC, a lighting control device that is easy to implement and operate is developed.The channel characteristics and noise characteristics are studied by analyzing the required characteristics and research status of hospital lighting.A solution based on carrier communication is proposed, the software and hardware are designed, and many experiments are carried out.Through many experiments, it is proved that the communication accuracy of this method is 98%, which is 6.3% higher than that of the conventional way.This mode can easily meet lighting needs and effectively monitor the conventional medical lighting system.
The design and research of this paper has indeed made some achievements.As a low-cost communication mode, power line carrier communication has incomparable advantages over other communication modes.But like other technologies, it also has its shortcomings and needs to be improved.For example, when applied to complex power channels, more attention should be paid to filtering; when the channel interference increases, more in-depth research is needed.This paper will continue to improve the lighting control system to make the control effect meet the needs.

Figure 1 .
Figure 1.Basic structure of intelligent control system in medical centers

Figure 3 .
Figure 3. Test results of download wave communication module under full closed condition

Figure 5 .
Figure 5. Multiple conditions carrier communication module test result This work was supported by "2021 key projects of the Science and Technology Research Program of Chongqing Education Commission"and"The funding from the Intelligent Design Discipline Group of Sichuan Fine Arts Institute".

Figure 7 .
Figure 7.Comparison between carrier communication and traditional communication