Distributed Power Allocation Game for Uplink OFDM Systems. Gaoning He, Sophie Gault - MOTOROLA LABS M é rouane Debbah - SUP É LEC Eitan Altman - INRIA INSTITUTE. Outline. System model Research background Distributed power allocation (DPA) game. System model. System settings - PowerPoint PPT Presentation
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• System settings– The uplink of OFDM system in a single cell– K users (Tx) are communicating with BS (Rx) using N subcarriers– Transmitters (Tx) have partial (or incomplete) channel state information (CSI).
• A simplified model (MAC)– K=2, N=1.– gk(t) is the uplink channel gain of user k.– Assume gk(t) has finite discrete channel states, following a certain distribution.
• Different channel state information (CSI) levels at Tx:– Complete CSI– Partial CSI– Statistical CSI
• Improve the performance of NE for the symmetric case– Assume the channel state gk (k=1,2) can be a1 and a2 with probability ρ1 and ρ2
respectively.– Assume both users coordinate to the same strategy set, i.e.
More precisely, . – Assume both users have the same maximum power constraint, i.e. – Then the problem goes to find the optimal strategy set that maximizes the
average capacity for user k.– The best strategy is given by:
• We study the power allocation problem in the uplink of OFDM system with partial knowledge at the transmitters. Most of the preview works on power allocation game was achieved under assumption of complete CSI at the transmitters.
• We introduced a theoretic approach to provide a natural setting for the construction of efficient distributed algorithms.
• We establish the existence and uniqueness of Nash equilibrium• For the symmetric case, we found the efficiency of NE can be improved by
forcing all users coordinating to the same optimal strategy set.• Future work will consider this problem to the case of MIMO and correlated
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