Advanced Positioning and Location based services in 4G Mobile-IP Radio Access Networks

2004 IEEE 15TH IEEE International Symposium on personal, indoor and mobile radio communications (PIMRC 2004), Barcelona, Spain, 5-8 september 2004.This paper proposes an evolved architecture from 3G networks to provide basic and advanced positioning methods for location based services in mobile IPv6-based radio access networks. We start analyzing current status of location-based services (i.e. LBS or LCS) and architectures in 3G networks as well as state-of-the-art research on LBS and mobile Internet. Next we set the requirements the solution should fulfill. We continue proposing the evolved architecture for support of basic and advanced positioning methods, using MIPv6 and HMIPv6 as mobility scenario for the mobile IPv6 based RAN, describing element's functions and changes from current approaches as well as description of the dynamic behavior. We complete the proposal with a bandwidth analysis of the signaling, identifying issues when planning implementation of LCS services in the network

Performance enhancement of outdoor IEEE 802.11 cellular networks

Most studies about the performance of IEEE 802.11 are limited to a single cell environment. Nevertheless, the idea of designing an outdoor cellular network based on WLAN IEEE 802.11 results very attractive, due to the several advantages that this technology presents: the low cost of the equipment, its operation in unlicensed spectrum and its higher data rates. If we compare the system performance in a cellular environment with its behavior in a single cell environment, we observe that its performance decreases considerably with the growth of the transmission data rate employed and due to co-channel interference. In this paper, we propose some enhancement mechanisms, in order to reduce the interference influence on network performance. Moreover, we study the viability of using sectorised antennas at the access points. We present its performance under different load conditions and compare this behavior with the results obtained in an isolated single cell environment, which has no interference.Peer Reviewe

A survey of localization in wireless sensor network

Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network

Topographical Automation of MANET using Reactive Routing Protocols

Wireless mobile ad-hoc networks (MANET) are characterized as infrastructure less networks. Topologies are formed with movement of regular nodes which has multi radio links and these regular nodes under demand behaves as backbone node (router) to forward packets across the network. These networks suffer frequent topology changes due to the dynamic stochastic process behavior of incoming nodes. Mobile ad-hoc networks lack load balancing that causes unnecessary packet loss and route break up in real-time data transmission. Area of operation, interference, and communication link range and path loss are the factors to affect the throughput of MANET. In this paper we evaluated the performance of AODV and DSR routing protocols which are enhanced by an Automation Topography, In our proposed Topographical Automation the location of incoming nodes are completely random and those will be confined themselves within a certain communication range such that the throughput is enhanced to meet better QoS level. As location of the nodes are system defined and quite automatic, nodes before being forwarded with the full assurance of successful session flows. It is often advantageous to position stable and capable relay nodes, including unmanned ground vehicles (UGVs) or unmanned aerial vehicles (UAVs), and unmanned under sea vehicles (UUVs) used by Defense to save cost as well as life

An energy-efficient adaptive modulation suitable for wireless sensor networks with SER and throughput constraints

We consider the problem of minimizing transmission energy in wireless sensor networks by taking into account that every sensor may require a different bit rate and reliability according to its particular application. We propose a cross-layer approach to tackle such a minimization in centralized networks for the total transmission energy consumption of the network: in the physical layer, for each sensor the sink estimates the channel gain and adaptively selects a modulation scheme; in the MAC layer, each sensor is correspondingly assigned a number of time slots. The modulation level and the number of allocated time slots for every sensor are constrained to attain their applications bit rates in a global energy-efficient manner. The signal-to-noise ratio gap approximation is used in our exposition in order to jointly handle required bit rates, transmission energies, and symbol error rates.This work has been partially funded by CRUISE NoE (IST-4-027738), MAMBO2 (CCG06-UC3M/TIC-0698) and MACAWI (TEC- 2005-07477-C02-02) projects.Publicad

Modular Software-Defined Radio

<p>In view of the technical and commercial boundary conditions for software-defined radio (SDR), it is suggestive to reconsider the concept anew from an unconventional point of view. The organizational principles of signal processing (rather than the signal processing algorithms themselves) are the main focus of this work on modular software-defined radio. Modularity and flexibility are just two key characteristics of the SDR environment which extend smoothly into the modeling of hardware and software. In particular, the proposed model of signal processing software includes irregular, connected, directed, acyclic graphs with random node weights and random edges. Several approaches for mapping such software to a given hardware are discussed. Taking into account previous findings as well as new results from system simulations presented here, the paper finally concludes with the utility of pipelining as a general design guideline for modular software-defined radio.</p