Thread safeĪ small GUI library for DOS, useful for embedded applications Agar applications are portable to a variety of platforms thanks to the SDL.support for SDL 2D and OpenGL rendering. Uses libsigc++.Ī cross-plataform, easy-to-use, non-intrusive C++ GUI library that runs on top of SDLĪ high-level graphical C application framework aimed primarly at 2D/3D games and simulations. N open source free class library primarily developed for use with X Window System. To read more from Jackson Corson, check out his other blogs: Wireless Reliability, Wireless Reliability - Modulation and Wireless Reliability - Channel Bounding.See interesting development methodology for more info These algorithms will help ensure the spectrum is shared equally by all parties, making the spectra more reliable and keeping its SNR up. This also will account for bounded channels as well. For example, if there are three APs operating in the same spectra, they will operate on separate channels so there is no overlap. This means that the spectra will be equally distributed in large area. It then analyzes this channel, which has higher SNR than the current channel. If the BSS is centralized on a channel that contains low SNR, then it announces a channel switch and changes to another channel. 802.11 APs constantly error checks the SNR of the channel they are operating on. While there may be issues with creating limited space on spectra, APs have the ability to work together to equally distribute the channels that are available. This will solve issues with increasing channel bounding because traffic is being sent in directed beams, lessening the possibility of overlapping BSSs. Since a higher SNR within a beamformed BSS is present, as interference will not be as much of a concern. With a BSS operating alongside one without beamforming, there is the issue of collisions much like before. In the case of an overlapping BSS, issues with beamforming may arise. This is because the directed beam does not incur interference from other devices within the BSS. This means that the WM will be used more effectively, only needing short pauses in the shared TXOP to deal with the Sounding PPDUs to maintain the correct beaming vector.īeamforming gives each transmission higher gain, meaning further transmission distance as well as relatively high SNR. With beamforming this is possible, allowing for the STA connected to an AP to transmit simultaneously. 802.11ac also expanded on the idea of creating a shared TXOP between devices. many chip makers are building beamforming into the newest ac devices. While little to no one implemented this technology in the 802.11n era, 802.11ac has a much brighter future on this front. It also outlined the idea of RDP which was designed to set up a shared TXOP between STAs. The 802.11n standard outlined the idea of beamforming or beamstearing technology. The question is: will this be viable in the large scale, especially as we bound more channels making multiplexing time increase? BEAMFORMING AND MU-MIMO While SGI does make the WM more prone to error, for the end user they will be ultimately unaffected. In tests done in a busy office area with several overlapping BSS, there was an increase in error, but yet again, the throughput of the BSS using SGI was significantly higher than that of a BSS with LGI. Is this true in an uncontrolled environment? While the error increased as predicted, the error did not affect the much higher rates that SGI predicted. However, the throughput of a BSS using SGI was significantly better than a BSS that does not. This is a significant increase in error, meaning that far more collisions are occurring. With SGI, we saw a 30% increase in packet error rate. Without SGI, there was little to no packet error. In tests done in a closed environment, there was a definite increase in packet error rate. This gives less time between transmissions, which could potentially cause collisions between transmissions from the same device. 802.11n outlined the idea of a short guard interval, decreasing the timer to 400ns. This gives a safe time between transmissions. Normally this is an 800ns timer that allows for time between bursts. Each transmission burst in 802.11 requires a guard interval that makes it so transmissions do not interfere with one another.
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