No abstract

Efficient consumption of available resources and fulfillment of increasing demands are the two main challenges which are addressed by exploring advanced multiple access schemes along with efficient modulation techniques. To this end, non-orthogonal multiple access (NOMA) is discussed as a promising scheme for future 5G traffic. NOMA enables the users to share same resource block, permitting certain level of interference. In this paper, we propose filtered OFDM (F-OFDM) as a transmission waveform for NOMA systems, as it offers all the advantages of OFDM with the additional provision of sub-band filtering to satisfy the diverse services of the users. We examine F-OFDM in both downlink and uplink NOMA systems. Error-related performances of both downlink and uplink F-OFDM NOMA systems are analyzed and compared with conventional OFDM NOMA system over Nakagami-m fading channel. The results show that the error performance of F-OFDM NOMA is better than that of OFDM NOMA. An improvement of about 2 dB and 1 dB in bit error rate is achieved in downlink and uplink F-OFDM NOMA, respectively. Monte Carlo simulations are conducted for different values of fading parameter m, supporting the obtained analytical results

The main motivation for considering noise to be Gaussian is the central limit theorem (CLT), which accounts for the perturbations that are additive in nature. However, a communication link may be severely affected due to the presence of potential non‐Gaussian sources of noise. This paper considers an important class of non‐Gaussian noise known as symmetric alpha‐stable (SαS) noise. To this end, using binary phase‐shift keying (BPSK) modulation, the bit‐error rate (BER) performance of a communication link subjected to Nakagami‐m fading and SαS noise is investigated by employing three approaches: exact, asymptotic and approximate. A closed‐form expression for the probability of error over Nakagami‐m fading subjected to bi‐parameter Cauchy–Gaussian mixture noise (BCGM) model is obtained. The effect of fading parameter (m) and impulsive index (α) on the BER is analyzed for different settings. The derived results corroborate with Monte Carlo simulations.

This paper investigates and quantifies the effect of different security protocols on the performance of a wireless LAN. Experiments were performed on a wireless test-bed and the data obtained was analyzed for throughput, delay and packet loss under different security scenarios. Both TCP and UDP traffic streams were analyzed at three different data rates. The effect of congestion is also quantified. The results reveal that no significant degradation in performance occurs by enabling security protocols in a wireless LAN.

No abstract