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Performance Analysis of Cooperative Spectrum Sharing for Cognitive Radio Networks Using Spatial Modulation at Secondary Users

In this paper, a new cooperative spectrum sharing protocol which avoids mutual interference between primary and secondary users by employing spatial modulation (SM) at the secondary transmitter (ST), is proposed for overlay cognitive radio networks. In the proposed protocol, ST cooperates with selective decode-and-forward (DF) relaying strategy to prevent error propagation. Primary transmitter (PT) exploits M-ary phase shift keying (M-PSK) modulation whereas ST utilizes SM (Nt transmit antennas and M- PSK). Since ST transmits PTs information by M-PSK symbols and its own information by antenna indexes, mutual interference at primary receiver (PR) and secondary receiver (SR) is removed. Upper bounds on the bit error probability (BEP) of the primary and secondary users are analytically derived and supported via computer simulation results which show that the proposed protocol significantly improves the bit error performance of both primary and secondary users compared to the non-cooperation case and the cooperative DF spectrum sharing protocol using superposition coding.

Cooperative spectrum sharing for cognitive radio networks using spatial modulation at secondary users

In this paper, a new cognitive radio network, which avoids the mutual interference between the primary and secondary users by applying spatial modulation at the secondary user, is proposed. The outage probabilities for the primary and secondary users are analytically derived and the superiority of the proposed system over non-cooperative transmission and the reference system where the M-ary phase shift keying (M-PSK) modulation is employed at both users is demonstrated.

A spectrum sharing protocol based on physical-layer network coding

In this paper, a spectrum sharing protocol based on overlay system paradigm is considered. The primary user is composed of a transmitter-receiver pair while a transmitter-receiver pair and a relay form the secondary user. The distances between transmitter-receiver pairs are so large; therefore, a relay is required for a reliable communication. All receivers are closer to the transmitter of the other user compared to its own. The secondary user shares its relay with the primary user to improve its performance; in return, it accesses the licensed spectrum. In the first time slot, both transmitters send their information to relay while receiver of the other user eavedrops this signal. Relay decodes the received signals simultaneously and applies bitwise XOR opreation according to physical-layer network coding technique. In the second time slot, R sends physical-layer network coded signal to both receivers which have the information bits of the other user from the first time slot. Both receivers access their intended information bits by applying XOR operation. Bit error probability for the considered protocol is analytically derived and supported via simulation results. Bit error perfomance of the considered protocol is compared with that of direct link between transmitter receiver pairs.

Bit error performance of a cooperative spectrum sharing protocol using spatial modulation

In this work, bit error probability for a spectrum sharing protocol applying spatial modulation (SM) at secondary users is derived. In the protocol primary transmitter (PT) applies M-ary phase shift keying (M-PSK) modulation while secondary transmitter (ST) employs spatial modulation (Nt antennas and M-PSK) to send primary M-PSK signal with respect to selective decode-and-forward strategy from the antenna it choose accord- ing to its own information. Carrying primary information by M-PSK modulation whereas secondary information by antenna indexes mitigates mutual interference between users. Upper bounds for bit error probability are analytically derived and supported via computer simulations. Performance of the protocol is compared with non-cooperation case and a reference system using M-PSK modulation at both users.

BER analysis of physical-layer coding in cognitive radio cross network

In this paper, a cognitive radio network which consists of a primary system with a pair of primary transmitter (PT) and a primary receiver (PR), and a secondary system with a secondary transmitter (ST), a secondary receiver (SR) and a secondary relay (R) is considered. It is assumed that the distances between the transmitter and receiver of both systems are so large that the aid of a relay is needed for a reliable communication. Moreover, the receiver of each system is assumed closer to the transmitter of the other system compared to its own transmitter. The considered protocol is based on the overlay paradigm where the unlicensed secondary system shares its relay with the licensed primary system and in return it accesses the licensed spectrum for its own transmission. In the first time slot, PT and ST transmit their signals to the relay while each receiver eavesdrops the signal of the other transmitter next to it. In the second time slot, the relay applies physical-layer network coding to the signal pair it decided in the previous time slot, through bit-wise XOR operation between primary and secondary information bits, modulates to the corresponding signal and broadcasts. Both receivers have the information bits of the other user from the signals received in the first time slot, hence they can extract their desired information bits by reapplying the bit-wise XOR operation to the bits received in the first and second time slots. The bit error probability (BEP) of the considered protocol for M-PSK modulation is analytically derived and supported via computer simulation results. The results show that the bit error performance of the primary system is significantly improved compared to the direct transmission case.