صفات الخطباء و مراعاة السامعين لتامين السلام في الجمتمعات الاسلامية

The religious sermon and the speaker play a keyrole in the Islamic societies in shaping and orienting the opinions, beliefs, approach and behavior of the masses. Addressing people is a great responsibility, for which the speakers will be held accountable to Allāh Almighty. Therefore, a speaker of Islām must be equipped with sound knowledge of Islām and well acquainted with the present time, too. Moreover, he must possesstherequired temperament of tolerance, compassion and consideration, while speaking to his audience. The example of the Holy Prophet Muḥammad(r) provides a complete model of conduct for today’s speakers. We notice that audiences are moved with the eloquence of the speakers. A careless speaker may drive his audience into the abyss of disappointment, alienation from Islām, terrorism andextremism, etc. ; On the other hand, he can alleviate their ignorance, reshape them to become the desired peaceful Muslims through his power of speech and influence of his character. In this paper, the author, tried to make the Islamic speakers realize their duties in respect of their audience in the light of the Sunnah of the Prophet(r).

Performance Analysis of Cooperative Communications over Fading Channels

Cooperative communications is a relatively new paradigm in wireless communications wherein communicating nodes collaborate with each other for information transfer. Such collaboration can achieve performance gains in terms of link reliability and coverage relative to non-cooperative communications under the same fading conditions. The Nakagami-m fading model is used extensively in the literature for performance analysis of cooperative systems and includes other models like Rayleigh as special cases when its fading parameter m takes particular values. Hyper-Rayleigh fading, which represents fading more severe than Rayleigh fading, is also represented by the Nakagami-m model with 0.5 ≤ m < 1. Hyper-Rayleigh fading has been observed in emerging wireless scenarios such as vehicle-to-vehicle communications and sensor communications within aircraft bodies. The performance analysis for cooperative links under hyper-Rayleigh fading is thus an interesting and challenging research problem. The submitted thesis aims to address performance analysis of dual-hop cooperative networks that employ fixed-gain/semi-blind Amplify-and-Forward (AF) relaying over Nakagami-m faded links. The first novel contribution of the submitted work is developing a new closedform expression for the average signal-to-noise ratio (SNR) at destination for a pure dual-hop AF network with the direct link in deep fade. Then for the case of hyperRayleigh faded relay-destination link, a new upper-bound on the average SNR at destination is devised and is shown to be tighter than a previously proposed upper-bound that is based on the well-known harmonic-geometric mean inequality. A power allocation (PA) strategy across source and relay nodes is proposed and is shown to provide measurable performance gains in average SNR and consequently the outage probability (OP) at destination when compared with equal PA. The second novel contribution of the submitted work is an extension of the work in the first contribution in that the system model includes the direct link for maximum ratio combining (MRC) at destination. Furthermore, the Nakagamim parameter that is restricted to the range 0.5 ≤ m < 1 for hyper-Rayleigh fading analysis presented in the first contribution is relaxed in the second contribution for error performance analysis of the considered dual-hop AF network. Specifically, a simple yet accurate closed-form approximation for the average bit error probability (ABEP) and closed-form expressions for its tight upper and lower bounds are derived for coherently detected binary modulation. The proposed theoretical results and simulations are in excellent agreement and our performance bounds are shown to be tighter than the previously proposed bounds for the case of unbalanced relayed links.