Wajahat Maqbool

Voronoi cell geometry based dynamic Fractional Frequency Reuse for OFDMA cellular networks

Interference Management (IM) is one of the major challenges of next generation wireless communication. Fractional Frequency Reuse (FFR) has been acknowledged as an efficient IM technique, which offers significant capacity enhancement and improve cell edge coverage with low complexity. In literature, FFR has been analyzed mostly with cellular networks described by Hexagon Grid Model, which is neither tractable nor scalable to the dense deployment of next generation wireless networks. Moreover, the perfect geometry based grid model tends to overestimate the system performance and not able to reflect the reality. In this paper, we use the stochastic geometry approach, FFR is analyzed with cellular network modeled by homogeneous Poisson Point Process (PPP). A dynamic frequency allocation scheme is proposed which take into account the randomness of the cell coverage area describe by Voronoi tessellation. It is shown that the proposed scheme outperforms the traditional fixed frequency allocation schemes in terms of per user capacity and capacity density.

Resource allocation for uplink M2M communication: A game theory approach

Machine-to-Machine (M2M) communication in cellular network is the driver for the future Internet of Things (IoT). The main challenge of M2M communication is the possibility of huge traffic in the uplink network that can cause problem in the network. This paper considers the problem of resource allocation among machines connecting in uplink to different femto base stations (FBSs). Resource allocation problem is analyzed through both non-cooperative and cooperative game to maximize their data rate and minimize utilization of power. Numerical result shows that by adapting non-cooperative game, all machines are getting data rate as per Nash Equilibrium (NE) or either they can set their strategy to maximize their data rate selfishly. On the other hand for coalitional game theory approach machines who participate in game are getting fair resource allocations.

Interference aware channel assignment (IACA) for cognitive wireless mesh networks

In this paper, we present the end-to-end interference aware concept of Cognitive wireless mesh network (CWMN). CWMN is the leading upcoming technology with the advantage of cognitive radio (CR). We demonstrate that the end-to-end interference model has the ability to perform better from SINR base model. To enhance the utilization of the unused spectrum the channel selection strategy should have some awareness mechanism to avoid interference. In this paper, novel interference aware channel assignment (IACA) algorithm is proposed. The end-to-end delay, packet delivery ratio and the throughput is used to estimate the performance of the proposed algorithm. The numerical results demonstrate that the proposed algorithm is closer to the optimum resource utilization.

Interference management for irregular cell geometry heterogeneous networks

Recent trends of bandwidth hungry application services in cellular communication put tremendous pressure on the network operators to significantly increase the system capacity. Within such perspective, the deployment of femtocells offers reliable and cost effective means to enhance the system capacity and indoor coverage. However, the random deployment of femtocells challenges several technical aspects of the existing cellular systems. The most obvious challenge is the occurrence of interference, which is more severe if spectrum management is not carefully considered. Fractional Frequency Reuse (FFR) has emerged as an attractive interference management technique due to its low complexity and significant coverage improvement. However, most of the previous work analyzes the performance of FFR for perfect geometry based models, whereas no practical deployment has such symmetry. In this paper we investigate the performance of FFR for cellular network based on irregular cell geometry. Furthermore, a novel FFR scheme is proposed for two-tier (macro-femto) network and the capacity of the system is evaluated. It is shown that the proposed scheme outperform the conventional frequency allocation schemes in term of capacity and cell edge performance.

Resource allocation for uplink M2M communication in multi-tier network

Machine-to-Machine (M2M) communication in heterogeneous cellular networks (HCNs) is “ONE OF THE DRIVERS” for the future Internet of Things (IoT). Coverage areas of HCNs cells may vary and the capabilities to handle users may vary also. To support massive numbers of machines connected in uplink in HCNs, one of the challenging issues of M2M communication is the possibility of huge traffic that can cause overload problem for specific tier/tiers. Increase the capacity of the network and avoid overload condition for BSs, machines will need to be pushed to the less loaded BSs even they offered a lower instantaneous SINR than the nearest BS. To push the machine to less loaded BS, biasing is introduced to enhance the coverage of the machine or group of machines. This paper proposes the solution of resource allocation in uplink by using cooperative game theory approach by introducing a biasing factor to enhance the overall system performance with fair utilization of radio resources.

Middleware framework for network virtualization in SHAAL

Wireless Sensor Network (WSN) has led to a new paradigm of Internet of Things (IoT). WSNs are usually deployed for a particular application. However, the demand of WSNs in Smart Home and Ambient Assisted Living (SHAAL) is the accumulation and allocation of multiple resources providing diverse services and applications. Virtualization of a sensor network is an emerging technique that permits aggregation of several independent heterogeneous sensor networks. The technique of virtualization poses overhead challenges like more processing and power consumption. In this paper efforts have been put forward by proposing an energy aware middleware framework that resides on the sensor nodes to achieve network virtualization for SHAAL.

An analytical model for handoff management and routing in CR-ad hoc networks

The paper addresses the Unified Handoff Management (UHM) scheme in Cognitive Radio Mobile Ad hoc Networks (CR-MANETs) with multiple users. In order to model the UHM, three key factors are considered: (1) channel availability and spectrum usage behaviors of the primary users (PUs); (2) the movements and the motility of the secondary users (SUs); and (3) channel heterogeneity and channel quality degradation. The main contribution is the construction of a Markov chain to model the evolution of the network (node position, node speed, channel quality, etc.) and the treatment of combined spectrum handoff and local routing. The comparison results clearly show an improvement in the performance of the UHM in terms of the route maintenance probability and the SU throughput. It is also proved that the channel transmission range and node mobility have significant effect on network performance compared to PU activity.

Online Priority Aware streaming framework for Cognitive Radio Sensor Networks

Due to the bursty nature of video traffic, streaming video in traditional Wireless Sensor Networks (WSN) is usually faced with distortion largely as a result of packet loss. Although the bandwidth aggregation characteristic of Cognitive Radio Sensor Networks promises to cushion this effect, this method will not be much different with the strategy of increasing throughput as has been employed in traditional WSN. Thus, the problem is yet to be properly addressed. More so, the fact that the most important of video frames (I-Frames) constitute more than half the streaming data (in low-motion streams) increases the possibility of distortion, which cannot be mitigated by solely increasing throughput. Online Priority Aware (OPRA) Streaming provides a detailed and simple framework for effective streaming that brings the important end-to-end distortion metrics to bear, directly on the in-network processing nodes. The algorithm selectively drops packets in the in-network processing nodes to maximize a defined Local Quality Index in order to protect end-to-end quality of experience (QoE). Preliminary results show its simplicity, its ability to deliver more QoE high priority packets to the sink and the satisfactory effects of the incurred overhead.

Multi-thread based middleware for sensor network virtualization

Wireless Sensor Network (WSN) has led to a new paradigm of Internet of Everything (IoE). In case of Ambient Assisted Living (AAL) that is based on the sensor network is usually deployed for single application. However, the future of WSNs based on sensors lies in the multiple application support and the aggregation of resources either in the form of hardware or software. To deal with the challenges of aggregation of sensors in the health care environment, virtualization of a sensor network is an evolving concept that enables aggregation of multiple independent heterogeneous sensor networks under one roof. In order to virtualize the sensors and networks, middleware layer role is the most dominant one. Furthermore, middleware for sensors poses the overhead challenges like processing time, memory utilization, sampling rate, delay, and power consumption. In this paper efforts have been put forward by proposing a middleware framework for sensor network that uses multi-threading technique that increases the sampling frequency and reduces the delay caused by the hardware abstraction layer that resides on top each sensor node. Mathematical model shows significant improvement in the processing time.

Fractional frequency reuse for irregular geometry based heterogeneous cellular networks

Indoor coverage and capacity are the major limitations of the current cellular systems. In such perspective, femtocells deployment has attracted considerable interest. However, the random and co-channel deployment of femtocells poses severe interference management challenges, especially at the cell edges. Recently, Fractional Frequency Reuse (FFR) has emerged an attractive technique for co-tier and cross-tier interference in multi-tier cellular deployment. However, most of the previous work analyzes the performance of FFR for perfect cell geometry models. Applying regular resource of the standard FFR scheme to the realistic cellular networks with high irregularity in the cell geometry and channel conditions leads to sub-optimal performance. In this paper we investigate the performance of FFR for two-tier cellular network based on irregular cell geometry. To capture the realistic network scenario the position of Macro Base Stations (MBSs) and Femto Base Station (FBSs) are modeled with Hard Core Point Process (HCPP) and Poisson Point Process (PPP) respectively. Furthermore, Sectored-FFR scheme with optimal sub-band allocation is proposed in this paper and the capacity of the system is evaluated. Simulation results show that the proposed Sectored-FFR scheme outperforms the conventional FFR schemes in terms of throughput and capacity.