الالتفات في القرآن الكريم دراسة تحليلية

The paper deals with the different styles  of iltifāt  found in the Holy Qur’ān  and coming out with a general scheme to account for its occurrence in order to enhance the understanding of the subtleties of this feature of Qur’ān ic style. To accomplish this, the research was carried out by way of an analytical study of the instances of iltifāt  in the Holy Qur’ān. As a prelude to the discussion of this subject, the research provides the meaning of iltifāt  among the Arab rhetoricians and the status of iltifāt  as one of the rhetorical tropes. The paper also discussed the significations of iltifāt  which have already been mentioned by previous scholars, and since those scholars touched on the significations only briefly, therefore, the research strived to explore further aspects of their interpretations making an effort to highlight new significations of iltifat and an attempt to introduce a new approach in looking at the iltifāt  phenomenon, in different Sura’hs of          Qur’ān, to demonstrate the application of this new perspective. Finally the research shows that the occurrence of iltifÉt in the Qur’ān  follows certain patterns that are related to the intended significations at the various locations where they appear in the Qur’ān.

Performance Analysis of Heterogeneous Cellular Networks With Load Balancing

Due to the ubiquity and exponential growth of cellular devices and data hungry applications, cellular data traffic demand has raised exponentially. To cope with the ever increasing traffic demands conventional cellular networks are shifting to heterogeneous cellular networks (HCNs) where low cost and low power small cell base stations (SBSs) are overlaid with the existing infrastructure of high power macrocell BSs (MBSs). Due to transmit power levels disparity, more users associate with the MBS than the SBS while following the maximum received power association scheme, resulting in an imbalanced load arrangement across the HCN. To balance the load, it is necessary to offload a fraction of users from the overloaded MBSs to low power SBSs. The main goal of this dissertation is to develop tractable frameworks in order to model and analyze different dynamics of load balancing (LB) for HCNs. First, this dissertation develops and analyzes a non-uniform HCN (NuHCN) model where the SBSs are deployed selectively in the available region. In the NuHCN, the available MBS coverage region is divided into sub-regions, such as cell-center region (CCR) and cell-edge region (CER). The MBSs provide service to the users in both the regions; hence, SBSs are assumed to be active in CER and provide service to cell-edge users (CEUs) only. The network performance is further improved by expanding the SBSs’ coverage in CER via cell range expansion (CRE) based cell association. The results demonstrate that the coverage and rate performances can be improved with LB in NuHCNs. In a co-channel HCN, the offloaded users experience severe macro-cell interferix ence (MCI) from the MBSs to which the users were associated prior to offloading. The MCI degrades downlink (DL) signal-to-interference plus noise (SINR) ratio severely. Use of an efficient interference management scheme can overcome this effect. As a second contribution, to accomplish better network performance via LB, a reverse frequency allocation (RFA) scheme is considered both in the uniform and non-uniform HCNs. The results show that better network performance is achieved in NuHCN in conjunction with RFA scheme employment. In the aforementioned contributions, the analyses were performed based on the coupled association (CoA) scheme, where a randomly selected user connects with the same BS in both DL and uplink (UL) directions. In the third contribution of this dissertation, decoupled association (DeA), where the user is associated with two different tier BSs simultaneously, is considered in conjunction with RFA scheme employment. The effects of this diverse bias configurations and RFA employment are studied for the coverage performance while considering both CoA and DeA. The results illustrate that with DeA, user-BS connectivity policy significantly improves the coverage performance.