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In this paper, we investigate the performance of Nth best relay selection networks with secrecy constraints where several eavesdroppers try to overhear the source message. In order to enhance the network security, a single jammer is introduced to jam the eavesdroppers. In addition, sub-optimal selection strategy is introduced to combat the malicious attempt of eavesdroppers. We derive the exact secrecy...
In this paper, a novel antenna selection strategy is proposed and analyzed for dual hop MIMO cognitive amplify-and-forward (AF) relay networks over independent non-identically distributed (i.n.i.d.) Nakagami-m fading channels. Spectrum sharing is employed with secondary users constrained by a limit on the interference to the primary receivers. All secondary users are equipped with multiple antennas...
The performance of differential pulse position modulation (DPPM) 60 GHz impulse radio (IR) systems with multiple receive antennas is studied in this paper. We derive the capacity and error probability of DPPM 60 GHz IR systems over AWGN channels. These results are then extended to Nakagami-m fading channels. Performance results show that DPPM is superior to pulse position modulation (PPM) in terms...
This paper considers the influence of multi-user interference (MUI) on an impulse radio ultra-wideband (UWB) communication system. Binary pulse position modulation is employed with time hopping (TH) for multiple access communications. The users are assumed to transmit asynchronously. A technique to reduce the MUI is presented. It is shown that this approach is effective for UWB systems in both additive...
Differential pulse position amplitude modulation (DPPAM) is considered in Ultra Wideband (UWB) communic-ation systems in this paper. DPPAM combines differential pulse position modulation (DPPM) and pulse amplitude modulation (PAM) to provide good system performances and low com-putational complexity. A typical format for a DPPAM signal in UWB systems is derived from that of pulse position amplitude...
Differential pulse position modulation (DPPM) is considered in Ultra Wideband (UWB) communication systems in this paper. A typical format for a DPPM signal in a UWB system is derived from that of a PPM signal. The error probabilities of DPPM with receive diversity over additive white Gaussian noise (AWGN) channels and Nakagami fading channels are analyzed. Performance results are presented which show...
The capacity of differential pulse-position modulation (DPPM) is considered in this paper. Since the formula of Shannon Capacity is effective only in the AWGN channel with continuous-valued inputs and outputs, while the channel employing M-ary DPPM modulation has discrete-valued inputs and continuous-valued outputs, we derive the modified formula which applies to calculate the capacity of a UWB system...
A selective approach is proposed to improve the performance of Time-Hopping (TH) PPM UWB image transmission system over indoor fading channels. We divided the image information into key information and secondary information. In the proposed approach, key information is transmitted with good channel condition, secondary information otherwise. The threshold of channel condition can be derived from the...
In this paper, we propose a cross layer approach to wireless image transmission over fading channels. We first extract the key information from the image and transmit this information only when the channel is good to ensure that most errors occur in the less important image information. The relationship between the channel SNR and Peak SNR (PSNR) of the received image is examined. Performance results...
The performance of time-hopping pulse position amplitude modulation (PPAM) for an ultra-wideband (UWB) communication system over fading channels is investigated based on the multipath fading statistics of UWB indoor wireless systems. Frequency selective fading channel is considered for multiple access environment, which is addressed with Gaussian approximation based on single user mode. Error probability...
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