The authors present an innovative wireless embedded system for logistic applications: it is a prototype of a portable appliance to manage operations in production activity. The system is based on a wearable device which is able to read products codes and allows the system to guide users through the different phases of warehouse's everyday life; by means of wireless IEEE 802.15.4 standard - on the ISM 2.4 GHz band - the system can transfer data, service and control messages and commands to and from its coupled management server. Moreover by an ad-hoc procedure based on a weighted minimum mean square error (W-MMSE) localization algorithm, the system is able to localize users within a typical logistic scenario. The system is addressed to retail markets, pharmacies, porterage and logistic activities thus allowing the user to work more efficiently and employing mobile a more ergonomic terminal: from intensive picking to packing, from load of goods from lines to lists and warehouse checks.

We present a novel and innovative wireless tracking system for service vehicles in areas where the vehicles position could affect people security and operational functionalities; a communication system to acquire and transmit mobile agents GPS position data to an area control station has been studied and implemented. As mobile agents (vehicles) are free to move over the operational area, the target of the system is to provide a reliable tracking service employing a wireless backbone, comprised of fixed stations. The novel solution proposed here will manage the communication between mobile agents and the backbone network with a specific AODV routing protocol, and the static backbone network with a co-existent different customized OLSR routing protocol

Abstract-Alternative code assignment policies for the forward link of a multicarrier DS-CDMA system employing the recently proposed quasi-orthogonal sequences are put forth in this letter. It is demonstrated how different allocation strategies of quasi-orthogonal codes alter the interference level suffered by active units; it is also shown how to shape the rate of interference growth as a function of the number of active users within the reference cell, implementing some specific code allocation patterns. The performance achieved by various schemes is assessed in a frequency selective fading environment, in terms of average bit error probability.

This work proposes an analytical model to investigate the behavior of a radio link control (RLC) protocol on the forward link of a mobile radio system and to relate its performance to transmission design. As a reference case, a multicarrier DS-CDMA architecture employing Walsh and quasi-orthogonal channelization codes, similar to the current cdma2000 system, is considered. Jointly modelling the features of the data link layer and of the underlying physical channels, it is possible to identify the interaction between transmission parameters and the RLC protocol behavior. The latter is assessed by analysis, determining the RLC protocol goodput and the average delivery time suffered by a data unit transferred over the radio channel, when two different coding approaches are adopted: namely, rate compatible punctured convolutional codes and code combining

This letter analytically determines the effects of selective diversity on the performance of a RAKE receiver in dense multipath channels featuring an arbitrary power delay profile. The approach devised permits assessing the symbol-error probability of the RAKE receiver with simple computations, and determining the influence on system behavior of different power delay profiles and number of resolved paths, as well as signal bandwidth.

The work investigates the behavior of a 3rd generation radio link control protocol on the forward link of a multicarrier DS-CDMA architecture that employs Walsh and quasi-orthogonal channelization codes. Protocol performance is assessed analytically, determining the average delay suffered by a data unit transferred over the radio channel. For alternative allocation policies of Walsh and quasi-orthogonal codes, the effects on throughput of different transmission qualities and size of protocol data units are evaluated.

Several code allocation policies, suitable for the forward link of a multicarrier DS-CDMA mobile radio system that employs Walsh and quasi-orthogonal sequences, are proposed. Their effect on system performance is evaluated in the presence of a single class of users, as well as when transmissions of different data rates are supported, owing to the adoption of the variable spreading factor technique.

Alternative code assignment policies for the forward link of a multicarrier DS-CDMA system employing the recently proposed quasi-orthogonal sequences are put forth. It is demonstrated how different allocation strategies of quasi-orthogonal codes alter the interference level suffered by active units; it is also shown how to shape the rate of interference growth as a function of the number of active users within the reference cell, by implementing some specific code allocation patterns. The performance, in terms of average bit error probability, achieved by various schemes is assessed in a frequency selective fading environment, and the advantages of different solutions highlighted.

We determine the effects of different diversity schemes on the behavior of a direct-sequence spread spectrum RAKE receiver which operates with random spreading sequences, in a multipath channel with arbitrary power delay profile. Two different receiver architectures, the former employing the L instantaneously strongest paths out of the N/sub r/ resolved ones, and the latter simply the L first paths out of the received N/sub r/, are confronted in terms of symbol error probability, when an M-level PSK system is assumed. The analytical approach devised for assessing such comparison gives the symbol error probability in terms of simple elementary integrals, and immediately evidences the influence on system behavior of the number of resolved paths, bandwidth occupancy of the signal and power delay profile, with a remarkably moderate computational effort.