Mudassar Ali

Energy Efficient Resource Allocation in D2D-Assisted Heterogeneous Networks with Relays

Heterogeneous networks (HetNets) supported with relays and device to device communication can be considered as a promising solution to realize the ambitious targets of the future fifth generation networks in terms of energy efficiency and capacity. HetNets necessitate optimal power allocation, spectrum resource allocation, and cell selection to meet the quality of service requirements. In this paper, we formulate energy efficiency maximization problem in terms of resource allocation and cell selection for HetNets, where objective is to maximize the network throughput per unit network power consumption. Formulated optimization problem is non-linear fractional programming problem. We use Charnes-Cooper transformation to convert proposed fractional programming problem into concave optimization problem. We propose outer approximation algorithm (OAA) to solve the converted concave optimization problem. The proposed algorithm is evaluated by extensive simulation work. The performance of ε-optimal solution obtained by OAA method is shown for different network parameters, such as number of users, required date rate, and capacity of network.

Smart heterogeneous networks: a 5G paradigm

An exponential growth in data demand on wireless networks and wireless link capacity approaching its theoretical limits, bound us to find new solutions and innovative network designs to handle the enormous amount of traffic. In this paper, we discuss long term evolution-advance (LTE-A) heterogeneous networks (HetNets) being a most effective solution to break this wireless cellular capacity crunch. LTE-A HetNets provide adequate increase in capacity by utilizing multi-tier architecture consisting of different type of cells i.e macro cell, small cell, relay and device to device. However this increase in capacity comes with certain challenges in HetNets outlined in this article. Considering inter cell interference coordination (ICIC) as biggest challenge in LTE-A HetNets, this article surveys state of the art LTE-A HetNets deployments with focus on ICIC. Effective ICIC techniques allow further substantial capacity increase. We give state of the art ICIC on air-interface as well as backhaul strategies for effective ICIC in LTE-A HetNets. Operators perspective of LTE-A HetNets with some insight to future of 5G LTE-A HetNets is provided. We also provide simulation results to show how LTE-A HetNets lead to realize ambitious targets of 5G technology in terms of capacity.

Secure Duobinary Signal Transmission in Optical Communication Networks for High Performance & Reliability

A numerical study is presented in this paper based on semiconductor laser chaos generation which is being used to hide multi-level data signal, i.e., duo-binary message to take the advantage of secure environment & higher data rates at the same time. Duobinary message is generated by using the combination of duobinary precoder, duobinary generator & RZ/NRZ pulse generator. Laser rate equations are used to model chaos generation through semiconductor laser whereas message is made secured by hiding it through chaos masking scheme. Propagation of chaos hiding the multi-format message is studied for long distance communication model. Synchronization between transmitter & receiver is achieved to obtain the acceptable eye-diagrams & quality factor (Q-factor). Q-factor is function of optical signal to noise ratio (OSNR) that gives a qualitative performance of receiver. It provides the minimum SNR to obtain specific bit error rate of signal. A comparison is made with & without deployment of chaos masking scheme on RZ & NRZ duobinary optical system to observe the penalty in terms of Q-factor. In addition, response of amplifier on chaotic signal due to its nonlinearities is investigated by varying the gain of amplifier.

SDN Orchestration for Next Generation Inter-Networking: A Multipath Forwarding Approach

Increasing trend of peering at Internet exchange points (IXPs) provides a topological and network management advantage to the Internet service providers (ISPs) that is otherwise not possible through individual peering arrangements with their neighboring domains. ISPs keep analyzing potential advantages to peer at geographically diversified IXPs. Increasing degree of multihoming in ISPs requires extensive coordination among ISPs in different roles (access and transit), for mutual benefit. We propose a novel approach to build a conducive inter-networking ambiance for future data centric applications. Our approach exploits edge multiplicity of transit ISPs present across different IXPs to leverage a cross layer coordination between network stack at access ISP subscribers and the network infrastructure. Software defined networking provides a useful apparatus to control IXP fabric and also empowers our multipath forwarding strategy for an optimal network resource utilization in the inter-domain configuration. Contributions of this paper include the derivation of abstracted overlay graph from an IXP centric inter-domain connectivity model. This graph is used to provide multipath forwarding for increased reliability and throughput over abstracted graph. Adaptive cross layer coordination increases the efficiency of the proposed framework and provides an online mechanism of forwarding the traffic across the domains. We have observed as high as 54% increase in throughput using proposed scheme as compared with single path routing and forwarding strategy currently employed at the Internet backbone.