Search results for "CDMA"
showing 10 items of 12 documents
Studies on high speed uplink packet access performance enhancements
2014
Efficient Hybrid Emergency Aware MAC Protocol for Wireless Body Sensor Networks
2018
International audience; In Body Sensor Networks (BSNs), two types of events should be addressed: periodic and emergency events. Traffic rate is usually low during periodic observation, and becomes very high upon emergency. One of the main and challenging requirements of BSNs is to design Medium Access Control (MAC) protocols that guarantee immediate and reliable transmission of data in emergency situations, while maintaining high energy efficiency in non-emergency conditions. In this paper, we propose a new emergency aware hybrid DTDMA/DS-CDMA protocol that can accommodate BSN traffic variations by addressing emergency and periodic traffic requirements. It takes advantage of the high delay …
Multi-user interference mitigation under limited feedback requirements for WCDMA systems with base station cooperation
2016
One of the techniques that has been recently identified for dealing with multi-user interference (MUI) in future communications systems is base station (BS) cooperation or joint processing. However, perfect MUI cancellation with this technique demands severe synchronization requirements, perfect and global channel state information (CSI), and an increased backhaul and signaling overhead. In this paper, we consider a more realistic layout with the aim of mitigating the MUI, where only local CSI is available at the BSs. Due to synchronization inaccuracies and errors in the channel estimation, the system becomes partially asynchronous. In the downlink of wideband code division multiple access …
Handover and Uplink Power Control Performance in the 3.84 Mcps TDD mode of UTRA Network
2003
In this article we consider the performance of the 3.84 Mcps time-division duplex (TDD) mode of UTRA (Universal Terrestrial Radio Access) network. We emphasize two of the radio resource management algorithms, handover and uplink power control, whose role in the overall system performance is studied extensively. First, a handover algorithm used in WCDMA (Wideband Code Division Multiple Access) standard is considered in a TDD-mode operation. This gives rise to a careful setting of different handover parameters, and the evaluation of the effects to the system performance. Secondly, the specified uplink power control algorithm is considered. Since it is based on several user-made measurements w…
Performance enhancements of MBMS and VoIP services in WCDMA/HSPA networks
2009
Performance of advanced transmission and reception algorithms for high speed downlink packet access
2008
Nykyisten kolmannen sukupolven (3G) matkaviestinverkkojen suorituskykyä voidaan parantaa huomattavasti käyttämällä erilaisia kehittyneitä tekniikoita tukiasemissa ja matkaviestimissä. Suorituskyvyn lisääminen on tarpeen langattoman liikenteen jatkuvasti kasvaessa. – Ihmisten liikkuvuus on huipussaan ja esimerkiksi työn sidonnaisuus yhteen paikkaan on vähentynyt. Tarve olla jatkuvasti yhteydessä tietoverkkoon on samalla lisääntynyt. Yhä useammalla on esimerkiksi ns. liikkuva laajakaista, jolla nopea Internet-yhteys on riippumaton paikasta, Nihtilä toteaa. Nihtilä tutki väitöskirjassaan erilaisten lähetin- ja vastaanotinalgoritmien suorituskykyä 3G-teknologia WCDMA:n (Wideband Code Division M…
Advanced receivers and antenna diversity in WCDMA HSDPA
2007
Blind source separation based interference suppression schemes for OFDM and DS-CDMA
2015
In statistical wireless signal processing, extraction of unobserved signals from observed mixtures can be achieved using Blind Source Separation (BSS) algorithms. Orthogonal Frequency Division Multiplexing (OFDM) and Direct Sequence-Code Division Multiple Access (DS-CDMA) can be pronounced as the well established predominant air interface communication techniques. Consequences of an effort taken and counteractive solutions to diminish the undesirable influences encountered within the wireless air interface of those techniques with aid of BSS schemes are disclosed. Filter coefficients for the receiver are ascertained with the support of a set of energy functions and the iterative fixed point…
Enhancing the performance of HSDPA communication with multipoint transmission techniques
2015
The evolution of mobile phones, tablets and other mobile communication devices has led to a significant increase in the amount of data delivered over mobile networks. In order to satisfy the climbing data rate demands of customers, existing mobile broadband networks are being expanded with new features that allow ubiquitous and consistent networking experience. This research presents three multipoint transmission techniques for Wideband Code Division Multiple Access (WCDMA) based High-Speed Downlink Packet Access (HSDPA) communication protocol. Multiflow, High-Speed Single-Frequency Network (HS-SFN) and Multipoint-to-Point Single-Frequency Network (M2P-SFN) enable transmission of user-dedicat…
Étude expérimentale d'un système hybride WDM/DS-OCDMA pour un réseau d'accès optique haut-débit
2008
National audience; Nous présentons une solution hybride WDM/DS-OCDMA pour l'application réseau d'accès optique haut-débit.