Investigation of channel allocation mechanism for Wi-Fi devices at 5GHz band

• Main Authors: Ching-Huai Ho, 何錦淮
• Other Authors: Hsin-Piao Lin
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/jd5zvf

碩士 === 國立臺北科技大學 === 電腦與通訊研究所 === 102 === This thesis focuses on investigating Wi-Fi devices interference and channel allocation mechanism at the 5GHz band. The overlap with the 802.11a/n standards 20/40MHz bandwidth channel occurs frequently when set to 80 MHz bandwidth on 802.11ac standard. This thesis would like to discuss the interference problems between 802.11a/n and 802.11ac by measurement experiments for the upcoming 802.11ac products. In this thesis, we use the Wi-Fi card with chipset maker Atheros platforms and wireless base station with Broadcom platform respectively. We use four kinds of infrastructure mode settings to simulate the interference phenomenon rising from actual communication condition in open space with multiple users using the same frequency channel. When set to 5GHz band on 802.11a/n and 802.11n/ac respectively, we use six kind of connection interference scenario to evaluate the Wi-Fi card performance by measuring throughput. The experimental results show that when the 802.11n users overlapping channels to each other, the performance will be substantially decreased around 30% to 70%. When 802.11n device working on 802.11ac secondary channel, 802.11ac device performance will be significantly decreased around 92% to 97%. In this thesis we also use third-party firmware to enter the wireless base station software environment and run a shell script for 802.11n channel selection. When users use the same channel with another user, the shell script will choose to use other free channels automatically. This could improve throughput performance near 36%.