Sergio Parolari

Link quality control benefits from a combined incremental redundancy and link adaptation in EDGE networks

A performance analysis of link quality control (LQC), comprising incremental redundancy (IR) and link adaptation (LA) in EDGE networks has been provided. Both simulated and real system measurement results demonstrate the superiority of the proposed combined IR+LA strategy over pure IR. LLC and TCP/IP protocol stack simulations show that a pure IR strategy causes upper layer protocol implications as well as frequent TCP retransmissions resulting in considerable throughput degradations especially under bad C/I conditions. In this case, a combined IR+LA strategy reduces the TCP/IP packet delay and avoids upper layer timer expiries by switching to a more robust coding scheme. Hence, under bad radio conditions, with IR+LA the application throughput is preserved at an optimum level.

Analysis of the spectral efficiency of a fully adaptive antenna array system in GSM/DCS networks

The fast increasing number of subscribers in mobile communication networks leads towards the investigation of methods for capacity enhancement of existing systems. GSM/DCS networks provide a number of already available features (frequency hopping-FH, power control-PC, discontinuous transmission-DTX) to reduce interference and therefore to increase capacity by means of a reduction of the frequency reuse factor. Methods based on smart antenna receivers have been under investigation to further enhance the spectral efficiency with the least impact on the actual hardware structures. A new adaptive space-time receiver has been proposed (Giancola et al., 1999) to cope with time varying channel and co-channel interference. Here we propose a complete study to evaluate the additional capacity gain of the proposed smart antenna system compared to other array systems in a modern fully-featured GSM/DCS network.

Spacetime processing for time varying co-channel interference rejection and channel estimation in GSM/DCS systems

In this paper is proposed a spacetime algorithm for co-channel interference (CCI) and intersymbol interference (ISI) reduction for GSM/DCS systems. The temporal channel for the Viterbi receiver and the beam-former weights for CCI rejection are estimated jointly by optimizing a suitable cost function for separable (or rank-one) space-time channels. The adaptive version of the algorithm guarantees to convergence within a TDMA slot (not only using the training sequence) and to track the time-varying channel and/or CCI. By taking into account for the integration capabilities provided by FPGA (field programmable gate array) enabling technologies, it is demonstrated the feasibility of a single chip JSTE carrier solution.

A novel signaling procedure for dynamic QoS control of multimedia applications in wireless mobile networks

This paper describes a novel signaling procedure designed to enhance standard transport layer protocols (RTP/RTCP) for the effective management of end to end QoS control over mobile radio networks. The basic signaling procedure has been originally defined in order to allow the QoS manager entity (at the Internet service provider side) to react fast to sudden radio link outage due to cell reselections. It utilises data link-transport layer inter-protocol signaling and a fast signaling mode. The procedure has been developed in details for its introduction within the GPRS/EDGE system; its effectiveness has been verified in a number of real scenarios where standard schemes have proved to be inadequate.