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. At the end, this text explores the effectiveness of the proposed solutions.
INTRODUCTION
Wireless Local Area Network (WLAN) is one of the most successful technologies in IEEE 802.XX standards family. WLAN provides free connectivity, mobility, and flexibility with a relatively low cost for users. The widespread use of WLAN technology in streaming videos and voice applications stimulated high bandwidth capacity for WLANs. Recently IEEE has announced latest WLAN standard 802.11ac. For 802.11ac to be effective, it requires minimum 80 MHz wide channel with optionally up to 160 MHz. The increase in bandwidth leads to problems like OBSS. OBSS problem occur when two or more BSSs operate in same channel and are close to hear each other. This is an undesirable situation where two or more BSSs compete for channel access and increase contention which ultimately degrades performance/efficiency of the WLAN system [1]. The problem was not critical with 802.11a/b/g/n where the channel bandwidth was reasonable. ...
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... on how many stations it can associate to if OBSS problem needs to be avoided. At the end, couple of novel approaches can potentially enhance performance of OBSS.
Works Cited
[1]. Papadopoulos G. Z., “On the enhancement of IEEE 802.11 overlapping APs capacity sharing,” September 2011, Available: http://georgiospapadopoulos.com/BScThesis.pdf
[2]. Smith G., Dillon D. and Janecek J., “Overlapping BSS Proposed Solution – ‘OSQAP’,” February 2006, Available: https://mentor.ieee.org/
[3]. Han B., Ji L., Lee S., Miller R. and Bhattacharjee B., “Channel access throttling for overlapping BSS management,” 2009, Available: http://www2.research.att.com/~slee/pubs/CAT-OBSS-icc09.pdf
[4]. Fang Y., Gu D., McDonald B. and Zhang J., “A two level carrier sensing mechanism for overlapping BSS problem in WLAN,” June 2006, Avaliable: http://www.merl.com/publications/docs/TR2005-156.pdf
Lab 1 demonstrates the capabilities of congestion control algorithms implemented by Transmission Control Protocol (TCP). It provides three scenarios to simulate these algorithms and will later compare the results.
J. A. Gutierrez ,M. Naeve , E. Callaway , M. Bourgeois ,V. Mitter and B. Heile "IEEE 802.15.4:adeveloping standard for low-power low-cost wireless personal area networks", IEEE Network, vol. 15, no. 5, pp.12 -19 2001
5. The thing that you will need to implement is the disabling of all unnecessary ports and services on the POS devices.
Figure 6 shows the WiMAX and WiFi coverage. Once can clearly see how large is the coverage of WiMAX.
... in Wireless Sensor Networks: Current proposal and Future Development, IEEE Xplore, Hong Kong, Oct- 2007.
The hospital needs to find a way to improve the tracking of Voice Over IP (VOIP) calls within the hospital and also wants to have a program to improve response time of medical personnel by using the GPS to locate the closes vehicle to the emergency. A design will need to be made of the Requires and Provides interfaces of two components that might be used in the VOIP system. A design of the interface is needed for two components that may be used in the vehicle discovery component to find the nearest vehicle to the incident with the Requires and Provides interfaces.
...efining a new and a better version of OSPF protocol that can support EAR to reduce more percentage of energy consumption.
The propose research will address a problem confronting many two year institutions in the present-day (i.e. how to best plan, design, and implement WLAN technologies). While WLAN technologies offer the benefits of mobility, reduced installation time, and decreased cost, many challenges must be met by institutions deploying them (Geier, 2005). These issues are related to security, speed, interoperability, and equipment selection, ease of use, reliability, signal interference, installation, and health risks.
The following is a brief illustration of the principles of GPS. For more information see previous chapter. The Global positioning System (GPS) is a satellite-base navigation system that provides a user with proper equipment access to positioning information. The most commonly used approaches for GPS positioning are the Iterative Least Square (ILS) and the Kalman Filter (EKF) methods. Both of them are based on psuedorange equation:
throughput by transmitting independent data streams on the different transmit branches simultaneously and at the same carrier frequency.
Print. The. Gordon A. Gow, and Richard K. Smith. Mobile and wireless communications: an introduction, McGraw-Hill International, 2006. Print.
Wireless is everywhere today whether at home working from your WIFI network to work where you might be linked a wireless network or even through your phone through a 3G or 4G network to connecting to an open wireless networks. As you can see for the most part people are connecting to wireless from the moment they leave their home till they get to work and then back. While wireless comm...
Hollows, P 2002, 'Essentials of a smooth-running network', Communications News, vol. 39, no. 7, p. 16.
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