Performance of a linear interference canceller for a ds/cdma synchronous system based on the ekf delay estimator

Since the conventional detector often fails to produce reliable decisions for a CDMA channel, several new multiuser detectors have previously proposed. In the present paper, the authors propose both a simple linear scheme for interference cancellation, which exhibits good performance, and a synchronism scheme based on the extended Kalman filter (EKF) to achieve synchronization among the different users at the base station, for a direct-sequence code-division multiple-access (DS/CDMA) synchronous system. The influence of the synchronism scheme on the performance of the interference canceller is analyzed under Rayleigh multipath fading.Peer ReviewedPostprint (published version

Técnicas de ARQ en un esquema de acceso por paquetes DS-CDMA

Peer ReviewedPostprint (published version

Un programa lector intel·ligent de text

El programa TexPert, creat per un grup de tècnics joves de Barcelona, es ven als EU

A combined polling and ISMA-DS/CDMA protocol to provide QoS in packet mobile communications systems

This paper presents a new mechanism that combines the flexibility of an access protocol such as ISMA-DS/CDMA with the ability of a polling mechanism to provide a specific bound for the access delay. This protocol is proposed for a packet transmission mobile communication system together with a scheduling algorithm that arranges the different transmissions depending on the quality of service required by the set of considered services.Peer ReviewedPostprint (published version

ISMA-DS/CDMA MAC protocol for mobile packet radio networks

In this paper an ISMA-DS/CDMA MAC protocol for a packet transmission network is presented. The main feature of this protocol is its ability to retain the inherent flexibility of random access protocols while at the same time reducing to some extent the randomness in the access in order to increase the system capacity. In this framework, the protocol is adapted to a frame structure similar to that specified in the UTRA ETSI proposal for third generation mobile communication systems. Additionally, some adaptive mechanisms are proposed that improve protocol performance by means of varying the transmission bit rate according to the channel load that is broadcast by the base station. As a result, an adaptive bit rate algorithm is presented that reaches a throughput value close to the optimumPeer ReviewedPostprint (published version

Performance analysis of an ISMA DS-CDMA packet data network

The efficiency of MAC protocols for a packet switching DS-CDMA network strongly depends on the offered traffic statistic. For bursty sources where transmission needs are restricted to short message lengths, a protocol such as S-ALOHA can be efficient. However, for longer messages, a reduction in the randomness is required in order to improve the system performance. This improvement can be provided by a protocol such as ISMA when combined with the DS-CDMA technique. In this paper an analytical approach to modeling the resulting ISMA CDMA scheme is presented, and some design issues regarding the number of codes to be used are presented.Peer ReviewedPostprint (published version

Hazelnut production and prospects in Spain

For many years, Spain was the fourth largest hazelnut producer worldwide, after Turkey, Italy and the USA. However, Spanish production currently occupies the tenth place with 10,500 t in 2017, due to the reduction of land used for cultivation, coupled with the growing importance of other producing countries: Azerbaijan, China, Georgia, Chile, Iran and France. In Europe, with 16% of world hazelnut production, in 2017, Italy is the main producer country (81%), followed by France and Spain, producing 6,7% and 6,5%, respectively. The hazelnut tree (Corylus avellana L.) grows wild in Spain. In 2017, the total cultivated area dedicated to this species was 12,806 ha, mainly (82%) concentrated in Tarragona, southern Catalonia. Finally, it is worth highlighting the sector's great investment in fruit processing technology. Currently, the main cooperatives offer semi-finished products to many European chocolate industries and have their own production of roasted products, in shell and flour, for direct sale.info:eu-repo/semantics/publishedVersio

Issues on packet transmissioin strategies in a TDD-TD/CDMA scenario

This paper presents a packet transmission scheme that deals with the problems of a TDD CDMA scenario with different levels of frame structure asymmetry in adjacent base stations by distributing the users in the slots depending on their Time Advance. A multiple access protocol and a scheduling algorithm are also proposed to provide a certain degree of Quality of Service.Peer ReviewedPostprint (published version