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Adaptive transmission energy consumption

  • US 9,253,727 B1
  • Filed: 05/01/2015
  • Issued: 02/02/2016
  • Est. Priority Date: 05/01/2015
  • Status: Active Grant
First Claim
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1. A method of operating an end node to wirelessly communicate with a central node, the end node comprising a processor and memory the method comprising:

  • receiving wirelessly a beacon signal periodically-transmitted from the central node;

    measuring a received power, PB-RX, of the beacon signal;

    reading locally-stored values of PB-TX and G representing a presumed transmitted power of the beacon signal and a performance goal of the end node, respectively;

    determining, for a given channel, a path loss, PL, based on the PB-RX and the PB-TX; and

    adaptively setting an energy level, EN-TX, of a message to be transmitted from the end node based on the PL and the G; and

    wirelessly transmitting the message to the central node according to the energy level EN-TX;

    wherein the adaptively setting includes;

    solving a standard optimization problem using the PL and the G as inputs to find a desirable minimized combination of at least two of;

    a level of power, PN-TX;

    a forward error correction coding rate, c;

    a spreading factor, SF; and

    a modulation format, M; and

    wherein the solving the standard optimization problem uses a cost function as follows;


    C(SF,c,PN-TX,PL,G)=(T(SF,c)+XT(SF,c,n,PN-TX,G))*(P(SF,PL)+XP(SF,c,n,PN-TX,G))wherein;

    SF is the spreading factor;

    c is the forward error correction coding rate;

    n denotes time dependence;

    PN-TX is a target value of EIRP (Effective Isotropic Radiated Power) and is assumed to be a constant;

    PL is the path loss;

    G is the performance goal;

    T(SF, c) is a time on air required to transmit the message; and

    P(SF, PL) is a power consumed by the end node; and

    XT and XP are a time-on-air weighting function and a total-transmission-power weighting function based on SF, c, n, PN-TX and G, respectively; and

    such that evaluation of the cost function at the PL and the G is represented as follows;

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