Orthogonal Frequency Division Multiplexing Access (OFDMA) has been increasingly deployed in various emerging and evolving cellular systems to reduce interference and improve overall system performance. However, in these systems Inter-Cell Interference (ICI) still poses a real challenge that limits the system performance, especially for users located at the cell edge. Inter-cell interference coordination (ICIC) has been investigated as an approach to alleviate the impact of interference and improve performance in OFDMA-based systems. A common ICIC technique is interference avoidance in which the allocation of the various system resources (e.g., time, frequency, and power) to users is controlled to ensure that the ICI remains within acceptable limits. This paper surveys the various ICIC avoidance schemes in the downlink of OFDMA-based cellular networks. In particular, the paper introduces new parameterized classifications and makes use of these classifications to categorize and review various static (frequency reuse-based) and dynamic (cell coordination-based) ICIC schemes.

Over the last few years, a substantial number of call admission control (CAC) schemes have been proposed for ATM networks. We review the salient features of some of these algorithms. Also, we quantitatively compare the performance of three of these schemes.

Enhanced Inter-Cell Interference Coordination (eICIC) is a proposed framework by the 3GPP to handle Inter-Cell Interference (ICI) in heterogeneous network (HetNet) environments. Almost-blank subframe (ABSF) is one of the time-domain techniques proposed in the eICIC framework as a candidate for deployment in LTE release 10 (LTE-Advanced). In this paper, a comprehensive ABSF framework is proposed to mitigate the interference in HetNet environments comprised of macro-cells and femto-cells. The ABSF framework proposes a tracking procedure to mark and unmark the macro-cell victim users. Also, new control message to coordinate between macro-cells and femto-cells is proposed, a novel approach to trigger the ABSF mode at aggressor Home eNBs (HeNBs), and enhancements to the macro-cell scheduling process. Finally, a novel approach for the estimation of victim users' signal-to-interference-plus-noise ratio (SINR) level during ABSF is proposed based on the well-known discrete Kalman filter. The performance evaluation results show that the proposed ABSF framework significantly improves the throughput of the macro-cell victim users with a slight degradation in the throughput of the femto-cells.

Spectrally-efficient and low-latency support of local media services is expected to be provided by enabling underlay direct Device-to-Device (D2D) communication mode in future cellular networks. Interference Alignment (IA) can enhance the capacity of a wireless network by providing more degrees of freedom. In this paper, we propose using IA techniques in a D2D underlay network to enhance spectral efficiency. We compare IA transmission and traditional point-to-point (P2P) transmission from the Bit-Error-Rate (BER) and sum-rate points of view. Furthermore, we propose three grouping schemes for the D2D users into groups of 3-pairs such that IA can be applied using a limited number of signal extensions. Results demonstrate that although traditional P2P transmission can achieve better BER performance; IA transmission is still able to achieve gains in the sum rate. Also, system simulations show that the cell total D2D sum rate can be improved using IA. A gain of up to 31.8% is shown to be attainable at a reasonable transmit signal power level.

5G networks are expected to bring the gigabits per second throughput level per user to reality by 2020. This is done using a combination of new and well known technologies such as C-RAN, self-organizing networks, ultra dense networks, massive MIMO, and millimeter waves. In new RAN architectures, C-RAN has been viewed as a promising 5G architecture that centralizes baseband processing units and virtualizes them into a resource pool. The baseband units are connected to the remote radio heads via high speed fronthaul links. Failure of any 5G cell site fronthaul means the loss of hundreds of gigabits, or even terabits. In this article, we present a novel cell outage compensation approach using new SHRs added to each cell site in the 5G network. These SHRs operate only in case of fronthaul/ backhaul failure of any cell site in the network. A new software defined controller is introduced to handle the self-healing procedures. The article also introduces a high-level simulation study that is carried out to assess the proposed approach. The simulation results confirm the advantages of the proposed approach in terms of the degree of recovery from failures.