Distributed transmission for cooperative wireless networks

Turo Halinen

    Research output: ThesisLicenciate's thesis


    In this thesis the impact of quantized channel feedback on the performance of a (coherent) distributed beamforming (DBF) scheme is studied. The analysis is done in the context of a wireless access network, and the goal is to provide an adequate broadband coverage for users located inside buildings. In the examined scenario, instead of trying to reach the serving base station (BS) directly, it is assumed that each mobile station (MS) receives assistance from a cooperative group of network elements that is placed in close proximity (e.g., in the same room or office). This cluster of cooperative network elements is formed by a large number of low-cost low-power relaying stations (RSs), which have fixed locations and are equipped with only one antenna. Closed-form approximations for three different performance measures are derived (i.e., outage capacity, ergodic capacity, and bit error probability), providing performance predictions and fundamental limits of the proposed system architecture. The analysis reveals that the end-to-end performance that is achieved when using a small amount of phase feedback information (per RS in the second hop) is very close to the full phase information upper bound, paving the way to use massive DBF architectures as a practical way to cope with high data rate in future wireless systems. In addition, to give grounds for the suggested DBF scheme, fundamental information on cooperative communication is given first. Concepts of relaying, heterogeneous networks, and multi antenna techniques are given a brief introduction in this thesis.
    Original languageEnglish
    QualificationLicentiate's degree
    Awarding Institution
    • Aalto University
    • Hämäläinen, Jyri, Supervising Professor
    • Dowhuszko, Alexis, Thesis Advisor
    Publication statusPublished - 2013
    MoE publication typeG3 Licentiate thesis


    • Cooperative communications
    • Distributed beamforming
    • Decode-and-forward relays
    • Heterogeneous networks
    • Limited feedback information
    • Massive network element deployments
    • Non-perfect channel knowledge
    • Performance prediction


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