Navrati Saxena

Dynamic duty cycle and adaptive contention window based QoS-MAC protocol for wireless multimedia sensor networks

Rapid penetration of small, customized wireless devices and enormous growth of wireless communication technologies has already set the stage for large-scale deployment of wireless sensor networks. While the need to minimize the energy consumption has driven significant researches in wireless sensor networks, offering some precise quality of service (QoS) for multimedia transmission over sensor networks has not received significant attention. However, the emerging new applications like video surveillance, telemedicine and traffic monitoring needs transmission of wireless multimedia over sensor networks. Naturally, offering some better QoS for wireless multimedia over sensor networks raises significant challenges. The network needs to cope up with battery-constraints, while providing improved QoS (end-to-end delay and bandwidth requirement). This calls for a suitable sensory MAC protocol capable of achieving application-specific QoS. In this paper, we have proposed a new QoS-based sensory MAC protocol, which not only adapts to application-oriented QoS, but also attempts to conserve energy without violating QoS-constraints. Performance modeling, analysis and simulation results demonstrate that the proposed protocol is capable of providing lower delay and better throughput, at the cost of reasonable energy consumption, in comparison to other existing sensory MAC protocols.

Dynamic Reservation Scheme of Physical Cell Identity for 3GPP LTE Femtocell Systems

A large number of phone calls and data services will take place in indoor environments. In Long Term Evolution (LTE), femtocell, as a home base station for indoor coverage extension and wideband data service, has recently gained significant interests from operators and consumers. Since femtocell is frequently turned on and off by a personal owner, not by a network operator, one of the key issues is that femtocell should be identified autonomously without system information to support handover from macrocell to femtocell. In this paper, we propose a dynamic reservation scheme of Physical Cell Identities (PCI) for 3GPP LTE femtocell systems. There are several reserving types, and each type reserves a different number of PCIs for femtocell. The transition among the types depends on the deployed number of femtocells, or the number of PCI confusion events. Accordingly, flexible use of PCIs can decrease PCI confusion. This reduces searching time for femtocell, and it is helpful for the quick handover from macrocell to femtocell. Simulation results show that our proposed scheme re- duces average delay for identifying detected cells, and increases network capacity within equal delay constraints. The 3rd Generation Partnership Project (3GPP) is work- ing on the standardization of asynchronous communication systems. This technology is being enhanced gradually en- suring higher user data rate, bigger system capacity, and lower cost. The wideband CDMA (WCDMA) system is standardized with 3GPP release 99/4 which is being de- ployed in the world. Release 5 is related to High Speed Downlink Packet Access (HSDPA), and it improves the downlink packet transmission speed theoretically up to 14.4 Mbps. High Speed Uplink Packet Access (HSUPA) is enhanced up to 5.76 Mbps in uplink, and it is standardized with the Release 6. We simply mention both HSDPA and HSUPA as High Speed Packet Access (HSPA). In release 7, High Speed Packet Access Evolution (eHSPA, HSPA+) is standardized. eHSPA is based on the HSPA network with a simple upgrade, and it supports more bandwidth efficiency and lower latency. The maximum data rate is 28.8 Mbps in downlink and 11.5 Mbps in uplink (1). How- ever, users still require further system improvements. The technology is dramatically enhanced in release 8, where the standard of Long Term Evolution (LTE) is currently being established. The main objectives of LTE are higher data rates, lower latency, increased capacity, enhanced coverage, and an optimized system for the packet switching network (2). LTE also considers a femtocell, which is referred to as a home base station for an indoor coverage extension and overall network performance enhancement (3). Recently, LTE-Advanced standard targeting of 1Gbps for low mobil- ity is being discussed in release 9. We look into general features and requirements of fem- tocells. Important issues related to access control are de- scribed, followed by our contributions and organization of the paper.

Mobility Management Survey for Home-eNB Based 3GPP LTE Systems

Abstract: The specification of the Home Evolved NodeB (Home-eNB), which is a small base station designed for use in residential or small business environment, is currently ongoing in 3GPP LTE (Long Term Evolution) systems. One of the key requirements for its feasibility in the LTE system is the mobility management in the deployment of the numerous Home-eNBs and other 3GPP network. In this paper, we overview the characteristic of Home-eNB and also describe the mobility management issues and the related approaches in 3GPP LTE based Home-eNB systems. Keywords : Home-eNB, 3GPP LTE (Long Term Evolution), Mobility Management 1. Introduction issues of HeNB in 3GPP LTE systems and related approaches A significant interest within the telecommunications industry has recently focused on the femto-cell which is defined broadly as low-cost, low-power cellular base stations that operate in licensed spectrum to connect conventional, unmodified mobile terminals to a mobile operator’s network [1][2][3]. Femto-cell has been actively discussed in 3

Multi-objective handover in LTE macro/femto-cell networks

One of the key elements in the emerging, packet-based long term evolution (LTE) cellular systems is the deployment of multiple femtocells for the improvement of coverage and data rate. However, arbitrary overlaps in the coverage of these femto-cells make the handover operation more complex and challenging. As the existing handover strategy of LTE systems considers only carrier to interference plus noise ratio (CINR), it often suffers from resource constraints in the target femtocell, thereby leading to handover failure. In this paper, we propose a new efficient, multi-objective handover solution for LTE cellular systems. The proposed solution considers multiple parameters like signal strength and available bandwidth in the selection of the optimal target cell. This results in a significant increase in the handover success rate, thereby reducing the blocking of handover and new sessions. The overall handover process is modeled and analyzed by a three-dimensional Markov chain. The analytical results for the major performance metrics closely resemble the simulation results. The simulation results show that the proposed multi-objective handover offers considerable improvement in the session blocking rates, session queuing delay, handover latency, and goodput during handover.

A new predictive dynamic priority scheduling in Ethernet passive optical networks (EPONs)

Efficient uplink scheduling in Ethernet passive optical networks (EPONs) is very important for maximizing the network capacity while maintaining the required quality of service (QoS). Several variants of dynamic bandwidth resource allocation have been proposed in recent research literature. However, the available techniques do not fully exploit the elastic properties of the user traffic. In this paper, we explore optimal predictive resource allocation strategies by exploiting the elasticity of QoS-constrained traffic and using the knowledge of traffic patterns of different service classes. We propose a predictive dynamic uplink bandwidth allocation scheme that offers lower access delay and packet loss rate, yet achieves a higher overall network throughput. We formulate a model for determining the traffic burstiness-dependent optimum prediction order that would enhance the quality of prediction with a minimum possible prediction-related processing overhead. We then demonstrate that, in a multi-class access scheduling, with respect to the conventional dynamic allocation strategies, our priority scheduling with judicious prediction of individual traffic classes can enhance the system performance significantly. Our analytic observations are supported by extensive simulation results.

Novel framework for proactive handover with seamless multimedia over WLANs

Supporting multimedia applications over 802.11 wireless LANs requires low latency and seamless handover between multiple access points. However, the existing handover process in 802.11 products suffers from very high delay and frequent service disruption, which are not acceptable for streaming multimedia applications. In order to reduce this high delay and service disruption, the authors have designed and implemented a new proactive handover strategy over 802.11. The strategy intelligently issues proactive scan and handover triggers to reduce the effective channel scanning delay. Subsequently, it reserves resources in advance, to reduce the handoff reconnection delay and provide necessary QoS guarantee. Using actual implementation and simulation study, the authors demonstrate that their proposed strategy is capable of achieving magnitudes of latency, jitter and throughput improvements during the 802.11 handover operations, thereby providing seamless multimedia transmission.

Optimizing Access Point Allocation Using Genetic Algorithmic Approach for Smart Home Environments1

In recent years, high-bandwidth and low-cost wireless technologies have emerged as a competitive element, enabling the smart home environment. On the other hand, with the increasing demands for various services, the current access point allocation schemes give rise to significant challenges for a stable connection service, bandwidth and load distribution. In this paper, we present an optimal access point allocation scheme based on genetic algorithm that attempts to optimize multiple parameters, such as bandwidth, and load-balancing requirements. The proposed allocation scheme provides a set of approximately efficient solutions, which allows a wireless user to choose an access point based on its capacity and load balancing, not only regarding its signaling strength or service set identifier. The simulation results are provided to demonstrate the impact of the proposed optimization procedure on overall system performance in terms of connection distribution, load balancing and call dropping probability.

Efficient IoT Gateway over 5G Wireless: A New Design with Prototype and Implementation Results

The growth of IoT is expected to herald a better quality of life and open up new industrial opportunities. However, it is also raising new challenges in resource constrained wireless networks. Originally designed for human-to-human wireless communications, present wireless networks fail to satisfy the huge connectivity and varying traffic requirements of IoT. Next generation 5G wireless networks are expected to exploit emerging features, like mmWave, massive MIMO, and C-RAN, for providing the enormous connectivity, resource pooling, and energy efficiency required to support commercial rollout of IoT. Exploring these emerging features, we develop 5G-enabled IoT gateways to communicate with the RRHs of 5G C-RAN. The gateways are endowed with efficient compression schemes to significantly improve uplink resource utilization. Our 5G C-RAN prototyping and laboratory experimental results point out a huge opportunity for supporting a massive number of IoT-enabled devices by sophisticated 5G C-RAN deployment and efficient IoT gateway development.

Energy Efficiency in Wireless Networks – a Composite Review

ABSTRACT Energy efficiency is one of the most distinguished area on which several research groups and organizations across the globe are progressively working. This paper focuses on various technologies for truncating energy consumption in wireless communication. This incorporates new network architecture, network resource management, and supreme physical layer methods. Network architecture embraces multi-hop mobile networks, distributed antennas, diverse networks, etc. Furthermore, network resource management schemes comprise cross-layer optimization, multiple radio access technologies, and the dynamic power saving. The supreme physical layer methods encompass cognitive radio, multiple-input multiple-output (MIMO), concerted communications, network coding, orthogonal frequency division multiplexing (OFDM), etc. We render an exhaustive survey of such techniques proposed by several organizations across the globe. We also discussed energy efficiency prospect in future wireless communication systems like 5G, mobile cloud computing, Internet of things (IoT), and big data. Finally, we confer the major challenges and open issues in these technologies.

Hybrid Directional Discontinuous Reception (HD-DRX) for 5G Communication

For mmWave directional air interface expected in 5G communications, current discontinuous reception (DRX) mechanisms would be inadequate. Beam searching, for alignment of beams at User Equipment (UE) and 5G base station (NR nodeB), cannot be avoided in directional communication. We propose to exploit dual connectivity of UE, to both LTE eNB and NR nodeB, for effective 5G DRX. We present a novel hybrid directional-DRX (HD-DRX) mechanism, where beam searching is performed only when necessary. Probabilistic estimate of power saving and delay is conducted by capturing various states of UE through a semi-Markov process. Our numerical analysis achieves 13% improvement in power saving for HD-DRX compared with directional-DRX. We validate our numerical analysis with simulation studies on real traffic trace.