Wi-Fi RF Module Design Based On The Coexistence With Bluetooth

Mobile communication network due to bandwidth and technology limitations could not satisfy people's demand for wireless internet access any longer. As the mainstream wireless access standard of WLAN, Wi-Fi can connect to the internet with high-speed anytime and anywhere. With maturing gradually, Wi-Fi meets the user requirement of wireless internet access greatly, so that Wi-Fi function are integrated into more and more mobile devices, and as standard configuration for mobile terminals like Bluetooth. In another side, Wi-Fi and Bluetooth both work at the 2.4GHz ISM band, the interference problem is inventible, which leads to data throughput decreased, voice quality deterioration and distortion, even broken the link in the extreme cases. Therefore, how to make sure these two technologies co-exist harmoniously side by side closely, which has been one of the hot issue and difficulties of research.As for the issue about collision between Wi-Fi and Bluetooth nearby, many effective solutions have been created, including PTA (Packet Traffic Arbitration),AWMA (Alternating Wireless Medium Access) and DSE (Deterministic Spectral Excision) based on Wi-Fi technology. Both PTA and AWMA are implemented by MAC of Wi-Fi, through coordinating scheduling of packet transmission between Wi-Fi and Bluetooth; DSE is implemented by PHY of Wi-Fi, through a programmable notch filter to notch out the narrow-band Bluetooth interference. Another typicall solution is AFH (Adaptive Frequency Hopping) based on the Bluetooth, through frequency hopping to avoid the interfered channel adaptively, which can improve the Bluetooth transferring performance greatly.The above solutions especially PTA are all applied very widely, however not involved the Wi-Fi working power consumption. In this paper, an innovative conception is proposed to save the power consumption based on the PTA, which is APC (Adaptive Power Control) and PTA joint algorithm. By the joint algorithm, Wi-Fi transmitting power will adaptively adjust by detecting the signal level. To realize and verify this algorithm, firstly the working principle is described in detail, the power class and corresponding power also are defined and classified.subsequently the Wi-Fi RF module collocated with Bluetooth is designed which includes the system function block diagram and program feasibility evaluation, Wi-Fi peripheral device selection, Schematic and PCB layout design around Marvell 88W8787 chip platform. And meanwhile the RF calibration program to calibrate the RF parameter especially powers corresponding to each power class is designed, RF index are tested and optimized. Finally, the actual Wi-Fi and Bluetooth testing platform is built to finish the compare measurement of the data transferring throughput and the power consumption. The experiments verify the joint algorithm can not only improve Wi-Fi data throughput, but also can save the power consumption: if only working in the minimum power class(PCL5, 0dBm), the operating current consumption will reduce nearly 40% compared to the original current consumption working at maximum transmit power, and the average current consumption will reduce 10%～20% ,which can increase the battery continuation capacity for Wi-Fi mobile equipment.