Exploració per tema "Multiuser channels"

Ara es mostren els items 1-20 de 21

    • A generic radio channel emulator to evaluate higher layer protocols in a CDMA system 

      Umbert Juliana, Anna; Díaz Romero, M. del Pilar (Institute of Electrical and Electronics Engineers (IEEE), 2000)
      Text en actes de congrés
      Accés obert
      Currently, we are involved in the standardisation process to specify the next mobile system generation. A wideband code division multiple access (WCDMA) system is considered in most of the region versions. It would be very ...

    • A novel support recovery algorithms and its applications to multiple-access channels 

      Fernández Muñoz, Marcel; Kabatiansky, Grigory; Miao, Ying (Institute of Electrical and Electronics Engineers (IEEE), 2022)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      A novel algorithm of a sparse vector support recovery in presence of noise is proposed. In contrary to known algorithms based on matrices with RIP-property our algorithm exploits properties of so-called separating codes. ...

    • Adaptive S-ALOHA CDMA as an alternative way of integrating services in mobile environments 

      Sallent Roig, Oriol; Agustí Comes, Ramon (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2000-05)
      Article
      Accés obert
      Code-division multiple-access (CDMA) schemes appear to be very promising access techniques for coping with the requirements of third-generation mobile systems, mainly because of their flexibility. This paper proposes an ...

    • Adaptive s-aloha cdma as an alternative way of integrating services in mobile environments 

      Sallent Roig, Oriol; Agustí Comes, Ramon (2000-05)
      Article
      Accés obert
      Code-division multiple-access (CDMA) schemes appear to be very promising access techniques for coping with the requirements of third-generation mobile systems, mainly because of their flexibility. This paper proposes an ...

    • An emulator framework for a new radio resource management for QoS guaranteed services in W-CDMA 

      Sallent Roig, Oriol; Pérez Romero, Jordi; Casadevall Palacio, Fernando José; Agustí Comes, Ramon (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2001-10)
      Article
      Accés obert
      In the context of third-generation (3G) systems a mix of services with different requirements are expected. Consequently, packet scheduling mechanisms for quality of service (QoS) guarantees will play a key role. This paper ...

    • Array joint detection for C/TDMA systems in UMTS environments 

      Antón Haro, Carles; Rodríguez Fonollosa, José Adrián; Rodríguez Fonollosa, Javier (Institute of Electrical and Electronics Engineers (IEEE), 1998)
      Text en actes de congrés
      Accés obert
      Two array-based schemes for intracell and intercell interference suppression are proposed. In both cases, the spatial and temporal characteristics of the propagation are jointly exploited by placing a narrowband beamformer ...

    • Beamforming and Multiuser Detection in CDMA Systems with External Interferences 

      Muñoz Medina, Olga; Fernández Rubio, Juan Antonio (ICASSP'99, 1999)
      Text en actes de congrés
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      Multiuser detection has been investigated to mitigate the near-far effect in CDMA systems. Antenna arrays have been shown to provide spatial diversity and cancel undesired signals. In this paper we consider the synergy of ...

    • Cross-layer schedulling strategy for UMTS downlink enhancement 

      Ferrús Ferré, Ramón Antonio; Alonso Zárate, Luis Gonzaga; Umbert Juliana, Anna; Revés Ballesté, Xavier; Pérez Romero, Jordi; Casadevall Palacio, Fernando José (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2005-06)
      Article
      Accés obert
      This article describes the benefits of including cross-layer information in the scheduling mechanism of a UMTS downlink channel. In particular, the information obtained from the fast power control algorithm is used to ...

    • Design and implementation of a wide-band real-time mobile channel emulator 

      Olmos Bonafé, Juan José; Gelonch Bosch, Antonio José; Casadevall Palacio, Fernando José; Femenias Nadal, Guillem (1999-05)
      Article
      Accés obert
      A new wide-band mobile channel emulator for the CODIT project is designed and implemented. The UMTS code-division testbed (CODIT R2020) is a research project within the European RACE-II program set up by the Commission of ...

    • Design and implementation of a wide-band real-time mobile channel emulator 

      Olmos Bonafé, Juan José; Gelonch Bosch, Antonio José; Casadevall Palacio, Fernando José; Femenias Nadal, Guillem (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 1999-05)
      Article
      Accés obert
      A new wide-band mobile channel emulator for the CODIT project is designed and implemented. The UMTS code-division testbed (CODIT R2020) is a research project within the European RACE-II program set up by the Commission of ...

    • Diversity in mobile communications for blind detection of block-coded modulations 

      Vázquez Grau, Gregorio; Rey Micolau, Francesc; Lamarca Orozco, M. Meritxell; Rodríguez Fonollosa, Javier (Institute of Electrical and Electronics Engineers (IEEE), 1999)
      Text en actes de congrés
      Accés obert
      Spatial, temporal, and frequency diversity structures are analyzed to address the blind equalization problem in the presence of time-variant frequency selective channels. The aim of the paper is to present equalization ...

    • DSP-based ionospheric radiolink using DS-CDMA and on-line channel estimation 

      Pijoan, J L; Socor, J C; Moran, J A; Tarrés Ruiz, Francisco (Institute of Electrical and Electronics Engineers (IEEE), 2000)
      Text en actes de congrés
      Accés obert
      In this paper, a new blind multiuser detection algorithm is presented. It can both cancel multiuser interference and estimate the multipath channel response in a blind way. The method has been specially conceived for low ...

    • High aspect ratio silicon dioxide pillars 

      Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Servera, F; Marsal, L F; Pallarès Marzal, Josep; Alcubilla González, Ramón (2005-06)
      Article
      Accés restringit per política de l'editorial
      This article describes the benefits of including cross-layer information in the scheduling mechanism of a UMTS downlink channel. In particular, the information obtained from the fast power control algorithm is used to ...

    • Interference power recycling in two-scale ad hoc wireless networks 

      Villares Piera, Nemesio Javier; Sala Álvarez, José; Rey Micolau, Francesc (Institute of Electrical and Electronics Engineers (IEEE), 2014)
      Text en actes de congrés
      Accés obert
      A two-scale ad hoc wireless network is envisaged in which the interference power generated in long-range connections is recycled by the surrounding wireless nodes in order to support their own short-range communications. ...

    • ML approaches to channel estimation for pilot-aided multi-rate DS/CDMA systems 

      Mestre Pons, Francesc X.; Rodríguez Fonollosa, Javier (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2002-03-31)
      Article
      Accés obert
      This paper analyzes the asymptotic performance of maximum likelihood (ML) channel estimation algorithms in wideband code division multiple access (WCDMA) scenarios. We concentrate on systems with periodic spreading sequences ...

    • Multiuser resource allocation optimization using bandwidth-power product in cognitive radio networks 

      Tachwali, Yahia; Lo, B.F.; Akyildiz, Ian; Agustí Comes, Ramon (2013-03)
      Article
      Accés restringit per política de l'editorial
      In this paper, the problem of resource allocation optimization is studied for a single-cell multiuser cognitive radio network in the presence of primary user networks. The spectral access of the cognitive radio network is ...

    • Near-far resistant CML propagation delay estimation and multi-user detection for asynchronous DS-CDMA systems 

      Rey Micolau, Francesc; Vázquez Grau, Gregorio; Riba Sagarra, Jaume (Institute of Electrical and Electronics Engineers (IEEE), 1999)
      Text en actes de congrés
      Accés obert
      Multi-user receivers in asynchronous direct sequence code division multiple access (DS-CDMA) systems require the knowledge of several parameters such as timing delay between users. The goal of this work is to present a ...

    • Pilot-aided ML schemes for joint beamforming and channel estimation in WCDMA systems 

      Mestre Pons, Francesc X.; Rodríguez Fonollosa, Javier (Institute of Electrical and Electronics Engineers (IEEE), 2000)
      Text en actes de congrés
      Accés obert
      This paper proposes semi-blind channel estimation and interference cancellation schemes for the reception of pilot-aided signals in WCDMA systems. It is shown that the performance of classical training-based schemes is ...

    • Redundancy in block coded modulations for channel equalization based on spatial and temporal diversity 

      Vázquez Grau, Gregorio; Rey Micolau, Francesc; Lamarca Orozco, M. Meritxell (Institute of Electrical and Electronics Engineers (IEEE), 1999)
      Text en actes de congrés
      Accés obert
      Linear block codes in the complex field can be applied in spatial and/or temporal diversity receivers in order to develop high performance schemes for (almost-) blind equalization in mobile communications. The proposed ...

    • Spatial distribution analysis with capture effect of a mobile S-ALOHA network 

      Covarrubias, David; Ruiz Boqué, Sílvia; Huguet, Joan; Olmos Bonafé, Juan José (Institute of Electrical and Electronics Engineers (IEEE), 1998)
      Text en actes de congrés
      Accés obert
      The throughput performance of a mobile S-ALOHA network can be improved considering the capture phenomenon, which also depends on the spatial distribution of the mobiles within the cell. We have studied the capture probabilities ...