Enhanced signal detection slgorithm using trained neural network for cognitive radio receiver

Abstract

<p>Over the past few years, Cognitive Radio has become an important research area in the field of wireless communications. It can play an important role in dynamic spectrum management and interference identification. There are many spectrum sensing techniques proposed in literature for cognitive radio, but all those techniques detect only presence or absence of the primary user in the designated band and do not give any information about the used modulation scheme. In certain applications, in cognitive radio receiver, it is necessary to identify the modulation type of the signal so that the receiver parameters can be adjusted accordingly. Most of the modulated signals exhibit the property of Cyclostationarity that can be used for the purpose of correct detection of primary user and the modulation type. In this paper, we have proposed an enhanced signal detection algorithm for cognitive radio receiver which makes use of cyclostationarity property of the modulated signal to exactly detect, the modulation type of the received signal using a trained neural network. The algorithm gives better accuracy of signal detection even in low SNR conditions. The use of a trained neural network makes it more flexible and extendible for future applications</p>

Automatic recognition of the digital modulation types using the artificial neural networks

“…Thus, the carrier's amplitude changes as a result of the modulation between two values correspond to the Zeros and Ones as shown in Figure 2. Figure 3 show the digital modulation scheme of the binary ASK [11]. This method of digital modulation corresponds to the frequency modulation (FM) method of analog modulation.…”

“…This frequency modulation is relatively simple and has low performance. The carrier frequency changes here between two values, when the digital modulation signal is a logical zero, the transmitted frequency is f1, while when the digital modulation signal is a logical one, the transmitted frequency is f2, as shown in Figure 2 while Figure 4 shows the digital modulation scheme of the binary FSK [11].…”

“…The PSK modulation is a form of frequency modulation, and the resulting signal after the modulation has a limited number of positions. When the number of phase positions of the output phase is two, the modulation method is called binary phase shift keying (BPSK) as shown in Figure 2 [11]. When phase positions of the output phase are four, the modulation called quadrature phase shift keying (QPSK).…”

“…In digital modulation techniques, an analog carrier signal is usually modulated by a binary message code, and this is carried out by changing one of the physical characteristics of the analog carrier (amplitude, frequency, phase or a combination of them) according to the change in the instantaneous value of the message signal containing the information [2,10]. When the signal passes through a channel, it loses some of its energy and this is due to the impedance of the channel which causes the attenuation [11]. The shape of the signal also changes due to the distortion.…”

Sensing schedule optimization to minimize interference with primary users in cognitive radio network

“…In another work, authors of [18] examined the resource sharing problem in OFDM based CR relay network with multiple relays to maximize the transmission rate. Accurate identification of the modulation scheme used to modulate PU signal is explored in [19]. Authors of [20] projected a preventive multi-channel access model for prioritized CR networks using queuing theory to resolve the spectrum scarcity issue.…”