Adnan K. Kiani

Load dependent dynamic path selection in multi-radio hybrid wireless mesh networks

Hybrid Wireless Mesh Networks provide improved connectivity and reliability over traditional wireless networks. However due to rapidly changing traffic patterns, such networks are more likely to experience congestion which leads to data loss. Inability to differentiate between congested links and select best possible paths dynamically can be very expensive in a rapidly changing network topology. This paper proposes D-WCETT (Dynamic Weighted Cumulative Expected Transmission Time), an enhanced version of the WCETT routing metric, with focus on forming routes based upon network load information. The proposed routing metric dynamically selects paths with least level of congestion by taking into consideration locally available queue information. We present an evaluation of our implementation via extensive simulations and results indicate that the proposed metric significantly outperforms its predecessor by virtue of its ability to distinguish and dynamically select least congested paths in a multi-radio environment.

Achieving energy efficiency through load balancing: A comparison through formal verification of two WSN routing protocols

Network lifetime is one of the most crucial factors that affect the performance of a Wireless Sensor Network (WSN). In order to maximize the network lifetime, it is essential that a routing protocol is designed from the purpose of energy efficiency. One way through which energy efficiency can be achieved in a protocol is by evenly distributing load among all the nodes in the network. This paper introduces Robust Formally Analysed Protocol for Wireless Sensor Networks Deployment with Load Balancing (RAEED-LB). This protocol takes the decision of selecting the next node on the basis of load balancing. The performance of RAEED-LB and RAEED is compared through formal verification. The formal verification results show that RAEED-LB achieves network lifetime gain in the range of 10% to 35% over RAEED.

Priority Based Energy Aware (PEA) Routing Protocol for WBANs

Wireless Body Area Networks (WBANs) is a new technology for remote monitoring of patients. Sensor nodes are placed on different parts of the body such as implants and on body to collect data and transfer to the Sink node. Change in body posture, placement of sensors, priority of sensor data and energy consumption makes routing very difficult. Therefore, a Priority based Energy Aware (PEA) routing protocol is proposed in this paper. Child nodes choose a parent node connected to Sink based on a cost function that depends upon priority, residual energy and distance of node. Residual energy facilitates load balancing i.e. selection of different nodes for transmission. Distance helps in successful packet delivery to the parent node and caters for body postures. Priority helps to select a best possible path to forward the critical data keeping in view the energy constraint in WBANs. Comparison of different cost functions with proposed PEA protocol for performance metrics such as network lifetime, throughput and residual energy reveals that the proposed protocol results in increased network lifetime, throughput improvement of around 50% and higher residual energy.

Optimization between throughput and fairness in WiMAX network

IEEE 802.16 based Worldwide Interoperability for Microwave Access networks (WiMAX) are increasingly being deployed for last hop broadband wireless access. In order to provide the high speed access to information resources broadband technology like WiMAX is needed. In this paper we compared different uplink scheduling algorithms of WiMAX mainly maximum carrier to interference and noise (Max C/I) algorithm and fair share (FS) algorithm. Max C/I algorithm is a throughput maximizing algorithm but FS algorithm reduces the network throughput as it provides equal time slots to every subscriber station (SS) in a cell. We develop our own algorithm which optimizes between Max C/I and FS algorithms.

Energy-Load Aware Routing Metric for Hybrid Wireless Mesh Networks

Hybrid Wireless Mesh Networks provide improved connectivity and resilience over legacy networks. However, in a highly mobile environment with intermittent connectivity among devices, such networks suffer from data loss. Mobile clients lose energy rapidly resulting in unstable links. Rapidly changing traffic patterns can also result in congestion leading to deterioration of network services. In this paper a new routing metric, ELARM, for hybrid wireless mesh networks is proposed. ELARM chooses best route based on link stability and network load conditions. An algorithm to evaluate link stability based on receiving nodes energy conditions is also proposed. We run a series of simulations to compare our proposed metric with two of its most promising predecessors namely WCETT and D-WCETT. The results show marked improvement in packet delivery ratio and average network latency for highly mobile environments at the cost of slight increase in routing overhead.

SHIM6 Assisted Mobility Scheme, an intelligent approach

Devices with multiple interfaces are the future of mobile internet. Site Multi-homing by IPv6 Intermediation-SHIM6 is a proposal presented in IETF to provide multi-homing support in IPv6 based networks. Although initially it was intended for static networks but recently it has been tested that the mobility performance of SHIM6 is much better than the currently adopted mobility service in Internet-Mobile IPv6. Failure detection and recovery in SHIM6 is performed through ReAchability (REAP) protocol. Due to the inherent flaws in MIPv6, some new protocols/techniques have been tested which improve the overall mobility performance in IPv6 networks. In this paper, we present a mechanism for providing a “make before break” mobility service. We call our proposed mechanism SHIM6 Assisted Mobility Scheme (SAMS) as it provides both mobility and multi-homing support. We implemented LinSHIM6 with our proposed intelligent switching in wireless environment and present the results. We compare SAMS with REAP for multiple locator switching scenarios. The comparison is made in terms of packet loss, jitter, throughput and data transferred. Through experiments, we show that the percentage packet loss during switching reduces from 24.71% to 1.72% when SAMS is used instead of REAP.

Network Adaptive Interference Aware routing metric for hybrid Wireless Mesh Networks

Wireless Mesh Networks provide a reliable, robust and resilient platform for broadband access. Main benefits of using Wireless Mesh Networks are their low cost, robustness, self healing, and self configuring properties. In Wireless Mesh Networks, routing metric determines the path from source to destination. Wireless link conditions can be affected by a number of factors including interference, congestion, mobility, and network topology. Routing metric needs to consider all these factors while making routing decisions. In addition, wireless link conditions do not remain static with time requiring the routing metric to be adaptive. Interference in Wireless Mesh Networks are of two types: inter-channel and intra-channel interference. Existing routing metrics for Wireless Mesh Networks either consider only one of the two interference types or do not capture changing network conditions. In this paper, we propose a new routing metric for Wireless Mesh Networks which takes into account both inter and intra-channel interference and is adaptive to changing network conditions. Our proposed metric is compared with the state of the art and shows throughput improvement of up to 20 percent and latency reduction of 25 percent.

Mobility and energy aware routing algorithm for mobile ad-hoc networks

Mobile Adhoc Networks (MANETs) consist of a set of mobile nodes that form a dynamically changing network without the use of an existing infrastructure. Every node in the network acts as the peer to its immediate neighbor. Each node is thus responsible for relaying data to neighboring nodes for ensuring communication between distant nodes. This information dissemination mechanism pattern consumes extra node energy thus making energy a critical parameter for ensuring increased network lifetime. This paper proposes a new energy and mobility aware routing protocol referred to as Mobility and Energy Aware AODV (MEAODV) protocol. The proposed protocol has shown through simulations to achieve 4–5% increase in Packet Delivery Ratio, 20–24% reduction in Convergence time and 10 to 15% increase in Network Lifetime when compared to most promising stability based variants of AODV, PersonalizedAODV (RAODV) and MulticastAODV (MAODV-X).

Network Coding for Energy Efficient Transmission in Wireless Body Area Networks

Abstract Wireless Body Area Networks (WBANs) is a technology that has revolutionized the health-care industry by allowing remote monitoring, early detection and prevention of diseases. Patients can be remotely monitored thanks to implant devices in the body or by placing nodes on different parts of the body. Often the deployed sensor nodes are constraint by limited battery sources and are required to continuously collect the data and transfer it to the sink node, thus requiring energy efficient communication schemes. In addition, in poor channel conditions, this data collection and transfer results in retransmission thus wasting useful energy. This work presents a cooperative network coding based transmission technique for spectrum and energy efficiency in WBANs. The bit error rate (BER) of the network coded path in comparison to direct communication approach is explored. The effect of WBAN path loss due to different node positions is also discussed. It is observed that node position greatly affects path loss and received power which in turn affect the BERs. Simulation results show that network coded cooperative communication strategy in WBAN channel with and without combining outperforms as compared to direct communication.

Cell edge detection based interference avoidance scheme for closed mode LTE femtocells

Femtocells have come up as a promising solution for indoor coverage and Quality of Service, QoS of the users. One of the major challenges in the wide deployment of the femtocells is the cross-tier interference among the users at the cell edges. A typical high interference case is the uplink interference caused by the non subscribed cell edge users at the closed mode femtocells. In dense urban scenarios this interference may occur frequently resulting in the high deterioration of the femtocell capacity and QoS of the users; thus affecting the over all cell throughput. Fractional Frequency Reuse, FFR based schemes are a common option to cater the problem. Although efficient in interference avoidance, FFR results in lower cell throughput. The proposed scheme is an effective threshold based interference avoidance scheme working on the principles of Universal Frequency Reuse, UFR to obtain higher cell throughput. The information of femtocells location or their power settings are not required in the approach. Consequently it requires minimum backhaul signalling between the macrocell and the femtocells. Simulation results show significant improvement of the proposed scheme in terms of macrocell throughput, spectral efficiency and SINR of the femtocell user.