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Access Schemes

The Experts below are selected from a list of 16446 Experts worldwide ranked by ideXlab platform

Chi Wan Sung – 1st expert on this subject based on the ideXlab platform

  • Uncoordinated multiple Access Schemes for visible light communications and positioning
    2016 IEEE International Symposium on Information Theory (ISIT), 2016
    Co-Authors: Siu-wai Ho, Chi Wan Sung

    Abstract:

    In visible light communication (VLC) systems, information are conveyed by visible light instead of radio-frequency electromagnetic waves. Based on received signal strength, accurate indoor positioning systems can also be built. Since a receiver obtains the superposition of signals from all light sources within line of sight together with ambient light, a multiple Access scheme is necessary for the receiver to distinguish the received symbol and signal strength from each light source. This paper proposes two multiple Access Schemes for VLC. The first scheme supports information broadcast and positioning. By using 2N timeslots, N transmitters transmit 2N – 1 symbols in total. The second scheme supports positioning only but places emphasis on minimizing the required timeslots. In each 2N timeslots for an odd integer N, the channel gains of 3N – 1/2 transmitters can be estimated.

  • ISIT – Uncoordinated multiple Access Schemes for visible light communications and positioning
    2016 IEEE International Symposium on Information Theory (ISIT), 2016
    Co-Authors: Siu-wai Ho, Chi Wan Sung

    Abstract:

    In visible light communication (VLC) systems, information are conveyed by visible light instead of radio-frequency electromagnetic waves. Based on received signal strength, accurate indoor positioning systems can also be built. Since a receiver obtains the superposition of signals from all light sources within line of sight together with ambient light, a multiple Access scheme is necessary for the receiver to distinguish the received symbol and signal strength from each light source. This paper proposes two multiple Access Schemes for VLC. The first scheme supports information broadcast and positioning. By using 2N timeslots, N transmitters transmit 2N − 1 symbols in total. The second scheme supports positioning only but places emphasis on minimizing the required timeslots. In each 2N timeslots for an odd integer N, the channel gains of 3N − 1 over 2 transmitters can be estimated.

C.n. Georghiades – 2nd expert on this subject based on the ideXlab platform

  • On a unified view of synchronous multiple-Access Schemes: a bandwidth efficiency perspective
    2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733), 2004
    Co-Authors: P.d. Papadimitriou, C.n. Georghiades

    Abstract:

    Due to complexity considerations, synchronous multiple-Access Schemes, such as TDMA, CDMA, and OFDM, have been mainly based on orthogonal (unitary) transformations of the multiuser signal, which makes the receiver less complex, at the cost of bandwidth efficiency. In future systems, however, it seems that the limiting factor will not be processing power, but rather bandwidth. Therefore there is a need for redesigning multiple-Access Schemes, or rather unifying their design, in a multiple-Access scheme that is bandwidth efficient. The efficiency in the bandwidth can he achieved by applying non-unitary transformations to the multiuser signal such that the multiuser interference can he handled by a reasonably complex receiver. In this paper we attempt to unify the design of the aforementioned multiple-Access Schemes to a scheme that efficiently utilities the bandwidth, given that receivers of reasonable complexity can be deployed.

  • WCNC – On a unified view of synchronous multiple-Access Schemes: a bandwidth efficiency perspective
    2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733), 2004
    Co-Authors: Panayiotis Papadimitriou, C.n. Georghiades

    Abstract:

    Due to complexity considerations, synchronous multiple-Access Schemes, such as TDMA, CDMA, and OFDM, have been mainly based on orthogonal (unitary) transformations of the multiuser signal, which makes the receiver less complex, at the cost of bandwidth efficiency. In future systems, however, it seems that the limiting factor will not be processing power, but rather bandwidth. Therefore there is a need for redesigning multiple-Access Schemes, or rather unifying their design, in a multiple-Access scheme that is bandwidth efficient. The efficiency in the bandwidth can he achieved by applying non-unitary transformations to the multiuser signal such that the multiuser interference can he handled by a reasonably complex receiver. In this paper we attempt to unify the design of the aforementioned multiple-Access Schemes to a scheme that efficiently utilities the bandwidth, given that receivers of reasonable complexity can be deployed.

Siu-wai Ho – 3rd expert on this subject based on the ideXlab platform

  • Uncoordinated multiple Access Schemes for visible light communications and positioning
    2016 IEEE International Symposium on Information Theory (ISIT), 2016
    Co-Authors: Siu-wai Ho, Chi Wan Sung

    Abstract:

    In visible light communication (VLC) systems, information are conveyed by visible light instead of radio-frequency electromagnetic waves. Based on received signal strength, accurate indoor positioning systems can also be built. Since a receiver obtains the superposition of signals from all light sources within line of sight together with ambient light, a multiple Access scheme is necessary for the receiver to distinguish the received symbol and signal strength from each light source. This paper proposes two multiple Access Schemes for VLC. The first scheme supports information broadcast and positioning. By using 2N timeslots, N transmitters transmit 2N – 1 symbols in total. The second scheme supports positioning only but places emphasis on minimizing the required timeslots. In each 2N timeslots for an odd integer N, the channel gains of 3N – 1/2 transmitters can be estimated.

  • ISIT – Uncoordinated multiple Access Schemes for visible light communications and positioning
    2016 IEEE International Symposium on Information Theory (ISIT), 2016
    Co-Authors: Siu-wai Ho, Chi Wan Sung

    Abstract:

    In visible light communication (VLC) systems, information are conveyed by visible light instead of radio-frequency electromagnetic waves. Based on received signal strength, accurate indoor positioning systems can also be built. Since a receiver obtains the superposition of signals from all light sources within line of sight together with ambient light, a multiple Access scheme is necessary for the receiver to distinguish the received symbol and signal strength from each light source. This paper proposes two multiple Access Schemes for VLC. The first scheme supports information broadcast and positioning. By using 2N timeslots, N transmitters transmit 2N − 1 symbols in total. The second scheme supports positioning only but places emphasis on minimizing the required timeslots. In each 2N timeslots for an odd integer N, the channel gains of 3N − 1 over 2 transmitters can be estimated.