Wi-Fi utilities [Release 2.0]

Functions for Octave for performing computations about Wi-Fi networks (as defined by the IEEE 802.11 standard). Measurements made on a rural open area have shown that the ns-2 two-ray CMU Monarch propagation model is too simplistic. In fact, ns-2 uses a double regression to approximate 2-ray, which is resonable for lower frequencies, such as GSM. For 802.11 frequencies, an exact 2-ray propagation model is more appropriate, as it accounts for holes in the signal strength that happen at the distances where the direct and reflected ray interfere destructively; this phenomenon may altogether prevent correct frame reception. Additionally, frame reception is not a yes-or-no condition based on a threshold power level at the receiver, but rather is well approximated by receiving error probability given by a simple AWGN (additive white Gaussian noise) channel model. wifiper is a function that computes PER (packet error rate) on a Wi-Fi link in rural area, without obstacles, given distance, packet length, speed and other parameters.