WiFi-PAP WiFi Based Prioritized Access Point

Abstract

Internet plays a vital role in every day life activities. There are several ways to access the internet. Communication is also facilitated through the internet. In- ternet can be accessed through wired or wireless networks. The basic building blocks of WLANs is Basic Service Set (BSS). BSS has two types of architecture namely ad hoc and infrastructure network. Most popular means of internet ac- cess are WiFi based Wireless LANs where the network is infrastructure network having an Access Point for the exchange of packets between the main server and clients or between clients. MAC layer mechanism uses IEEE 802.11 which de nes Distributed Coordination Function (DCF). DCF employs CSMA/CA with binary exponential backo . With the advance in technology the mobile devices are up- graded to incorporate WiFi interfaces so that it supports WiFi hotspots. But the performance of WiFi hotspots are extremely poor compared to the demand in us- ing these technologies. The reason being that a single Access Point has to handle all the downlink ow to its clients or stations though getting the same opportu- nity to access the channel by contention with the other stations. In case when the downlink tra c ow is greater than the uplink tra c ow the AP has backlogged packets and packets are dropped consequently degrading the performance at the AP. This creates an asymmetric situation at the AP. The objective of our paper would be to reduce the tra c asymmetry and provide strict fairness to all the competing stations and the AP. We alter the access method of the AP to remove the asymmetric condition at the AP. AP will be given higher priority to access the medium hence when it has some packets to send then AP will send it rst. Stations would compete normally but due to AP having shorter IFS therefore the AP gets access much more. In case of a collision it would normally backo as in CSMA/CA. Our proposed scheme removes asymmetric condition due to the as- signment of higher priority to the AP therefore no queue build up at the AP. This also reduces the overall delay during communication and the collision probability reduced. Our proposed scheme might provide better fairness among AP and the stations as it contends normally. .