Improving the Overlapping Basic Service Set Problem Essay

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Wireless LANs have expanded greatly and rapidly in recent years. The expansio¬¬¬¬¬n has caused many benefits to the end users but at the same time it has introduced problem of overlapping BSS (Basic Service Set) where BSS (i.e. WLAN cells) is fundamental block of IEEE 802.11 WLAN architecture. OBSS occurs due to two or more unrelated BSSs are used at the same place, at the same time and with the same frequency channel. With the expansion of channel bandwidth to 80 MHz (may be, 160 MHz) in upcoming standards, the OBSS problem is likely to be very severe in the future. This paper examines how OBSS can be harmful to the networks and how it can be avoided using beam forming, distributed coordination across different APs, and power management.…show more content…
The problem becomes intense when there are many OBSS using the same channel. The wide range WLAN usage has caused “tragedy of commons” problem especially at public places. OBSS cause problems such as low efficiency, higher congestion and low data rate. OBSS is a problem for 802.11 when it is intended to use for applications which require QoS. EDCA does not solve this problem as it does not require other BSSs to coordinate. Admission control only solves bandwidth allocation problem within a single network and does not address OBSS [2]. POTENTIAL SOLUTIONS A number of solutions have been recommended in the past up to today to reduce potential interference due to OBSS problem. Frequency channel assignment can be a solution where BSS, during initial setup, scans the area to avoid channels that are already being used at other BSSs in the same area [1]. This solution can be useful only if the network has been carefully designed. Second solution can be dynamic channel switching. Channel switching has the same concept like frequency channel assignment but it periodically checks for any OBSS situation. If an AP detects other BSS on the same channel then it will switch to different channel. A third solution can be falling back to narrow band mode when two BSSs operate on the same channel [1]. So, if two BSSs found to be operating on same 80 MHz channel (in case of 802.11ac), they both can fall back to two different 40
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