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...ss applications. Frequency-flat vs. frequency-selective fading. If the bandwidth-delay spread product of the channel satisfies, B × τmax ≥ 0.1, the channel is generally said to be frequency-selective =-=[19]-=-. Otherwise, the channel is said to be frequency-flat. The variation of the matrix-valued transfer function �H(f) = � ∞ 0 H(τ)e −j2πfτ dτ (7) November 4, 2003 DRAFT 9swill depend on the delay spread a...

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...empirical data and, after compensating for attenuation due to intervening walls, it was found that the signal strength varies with the distance in a trend similar to the generic exponential path loss =-=[25]-=-. In our simulation, we use the i=1 (ssi − ss′ i )2 to Probability 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Euclidean − No Attack Euclidean − Attacked Median − No Attack Median − Attacked 0 0 5 10 15 20 ...

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...ed at a distance R from a transmitter is given by Prx Ptx Q k Zk R2b (1) where Ptx is the average power measured 1 m away from the transmitter3; b is the amplitude loss exponent4; and fZkg are independent random variables (RVs), which account for propagation effects such as multipath fading and shadowing. The term 1=R2b accounts for the far-field path loss with distance R, where the amplitude loss exponent b is environment-dependent and can approximately range from 0.8 (e.g., hallways inside buildings) to 4 (e.g., dense urban environments), with b 1 corresponding to free-space propagation [48].5 The proposed model is general enough to account for various propagation scenarios, including the following. 1) Path loss only: Z1 1. 2) Path loss and Nakagami-m fading: Z1 2, where 2 Gðm; 1=mÞ.6 3) Path loss and log-normal shadowing: Z1 e2G, where G Nð0; 1Þ.7 The term e2G has a lognormal distribution, where is the shadowing coefficient.8 4) Path loss, Nakagami-m fading, and log-normal shadowing: Z1 2 with 2 Gðm; 1=mÞ, and Z2 e2G with G Nð0; 1Þ. For cases where the evolution of signals over time is of interest, we consider the waveform relationship between 2Time an...

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... 802.11n as a superset of 802.11a/g. Packet Delivery versus RSSI/SNR. Textbook analyses of modulation schemes give delivery probability for a single signal in terms of the signal-to-noise (SNR) ratio =-=[8]-=-, typically expressed on a log scale in decibels. This model holds for narrowband channels with additive white Gaussian noise. It predicts a sharp transition region of 1–2 dB over which a link changes...

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...cus on square M-QAM modulation, i.e., M ∈ {4, 16, 64, · · · } or equivalently b ∈ {2, 4, 6, · · · }, since there are exact expressions for the symbol error probability of square M-QAM modulation (see =-=[17]-=-). We can easily generalize our analysis to include odd values of b by using an approximate expression for the symbol error probability. We define the utility function of a user as the ratio of its th...

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...ij = k dm , where dij is the ij distance between the transmitter of link j and the receiver of link i, k is a constant that depends on system parameters such as the carrier frequency and antenna gain =-=[29]-=-, and m is the path loss exponent. For the computations that follow, we take m = 4, k = 1, N0 = 1, Ev = 50, ∀v ∈ V . Thus if a transmitter transmits at unit power to a receiver at a distance of 1m, th...