Design And Implementation Of 2.4G Communication Systems For Wireless AP

With the rapid development of the mobile Internet today,people have higher requirements for the Internet experience.From the original 2G and 3G access to the Internet to the currently used 4G and the soon to be commercially available 5G,the data throughput rate is increasing exponentially.The IEEE work group has developed a series of wireless access standard protocols.The 2.4G and 5G bands are wireless local area network(WLAN)operating bands.Since 2.4G and 5G are high-frequency electromagnetic waves,the attenuation in space is very fast and the coverage is very limited.This theory studies the 2.4G band WiFi signal amplification,design a 2.4G WiFi band amplification relay system,effectively improving the signal coverage blind spot strength and Internet experience.The following problems can be solved:First,it can effectively solve the problems of multiple rooms,thick walls,and large space;secondly,it can effectively solve problems that cannot be covered by multiple floors,and the third can share WiFi access of neighbors.The content of this article is as follows:(1)The theory of wireless communication is analyzed theoretically,and the differences between digital modulation methods such as QPSK,OFDM,QAM,etc.,as well as the impact on receiver and transmitter performance are analyzed.Different modulation methods should be used for different transmission rates.(2)The implementation program uses Qualcomm's AR9331 2.4G wireless WLAN processor,fully meet the basic requirements of 802.11n protocol,using Zentel's A3S28D40FTP-128M as DRAM,PI's TNY264GN as a switching power supply chip,the overall design is not only stable,but also Lower power consumption,support for burning OpenWrt system,flexible firmware modification and add packages on OpenWrt.(3)The inverted F antenna design has the characteristics of small size,flexible structure and easy matching,and the error between the simulation result and the actual test result is smaller.High-frequency electromagnetic waves depolarize on walls and obstacles.Horizontal polarization and vertical polarization transform each other.Inverted F antennas have polarization components both horizontally and vertically,making them particularly suitable for 2.4G wireless short-range communications.(4)The electromagnetic compatibility processing of the switching power supply of the power supply part and the radio frequency circuit,reducing the loop area and reasonable grounding processing can ensure the integrity of the signal and make the system as safe and stable as possible.Test results show that at a distance of 15 meters from the router,when the system is powered on,the power supply ripple is 4.36mV,the carrier frequency is around 2.4Ghz,the receiving sensitivity is-78.7dBm,and the transmitting power is less than or equal to 19.5dBm at the resonance point.The VSWR of the antenna is 1.01,and the average wireless communication rate is 68Mbps,which is three times higher than the WiFi signal from the router at the same distance,and the wireless relay function is realized.