If each packet includes N p symbols, after M-ary digital modulation of rate R n bits/symbol, each packet is mapped to a bit block containing N p × R n bits.
Table 2 summarizes experimentally the performance and results in terms of digital transmission rate (symbol rate or modulation rate), maximum distance, and frequency modulation according to the considered wireless protocols by the Xbee RF modules and Virtex II technology.
These figures give snapshots of the real-time digital modulation in the case of the transmission data rate of 250 kbps (the maximum serial interface data rate of the XBee Pro modules [18] allowed with a clk_out signal frequency equal to 250 kHz) with a distance frame value of N = 500 clock cycles, allowing signal captures.
In order to simplify the simulations, the equivalent digital channel (with channel coding and digital modulation) was assumed error-free for source-coding rates below the capacity of the AWGN channel.
Each data rate is derived from a coding algorithm for error correction, a digital modulation process, and a spread spectrum technique.
where N sc is the number of data carriers per channel, R C is the code rate, and M represents the number of constellation points in the digital modulation scheme used.
Advanced wireless communication systems use sophisticated digital modulation schemes as well as space time diversity in order to provide high data rates.
Parameter Value Sampling frequency, Fs 1.5 MHZ Carrier frequency, Fc 150 kHZ Symbol rate, Rs 12500 Symbol/s No. symbols, Ns 100 Symbols Simulation parameters of digital modulation used in training, validation, and evaluation of the proposed algorithm.
The demand for reliable, high data rate transmission has increased significantly these days, which leads the way to adoption, of different digital modulation techniques.
