TY - JOUR

T1 - Energy-efficient power allocation over Nakagami-m fading channels under delay-outage constraints

AU - Musavian, Leila

AU - Le-Ngoc, Tho

PY - 2014/8

Y1 - 2014/8

N2 - This paper presents an energy-efficient power allocation strategy for Nakagami-m flat-fading channels with a delay-outage probability constraint. The operating input transmit power value is limited to P-max. The energy efficiency (EE), expressed in units of b/J/Hz, is represented as the ratio of the effective capacity to the sum of transmission power (P-t) and circuit power (P-c). Since the EE-maximization objective function is quasi-concave, a unique global maximum exists. By using fractional programming, we develop an EE-optimal power allocation strategy that consists of two steps: 1) obtaining the power level (P) over bar (un), at which the maximum EE can be achieved, and 2) distributing the power optimally based on the minimum of P-max and (P) over bar (un). We prove that while (P) over bar (un) monotonically increases with P-c, the maximum achievable EE is a monotonically decreasing function of P-c. The analysis further allows us to derive the EE of three important cases: non-fading channels, extremely stringent delay-limited systems, and systems with no delay constraints. Simulation results confirm analytical derivations and further show the effects of the circuit power, fading duration, and fading severeness on the achievable EE and effective capacity of a delay-limited fading channel.

AB - This paper presents an energy-efficient power allocation strategy for Nakagami-m flat-fading channels with a delay-outage probability constraint. The operating input transmit power value is limited to P-max. The energy efficiency (EE), expressed in units of b/J/Hz, is represented as the ratio of the effective capacity to the sum of transmission power (P-t) and circuit power (P-c). Since the EE-maximization objective function is quasi-concave, a unique global maximum exists. By using fractional programming, we develop an EE-optimal power allocation strategy that consists of two steps: 1) obtaining the power level (P) over bar (un), at which the maximum EE can be achieved, and 2) distributing the power optimally based on the minimum of P-max and (P) over bar (un). We prove that while (P) over bar (un) monotonically increases with P-c, the maximum achievable EE is a monotonically decreasing function of P-c. The analysis further allows us to derive the EE of three important cases: non-fading channels, extremely stringent delay-limited systems, and systems with no delay constraints. Simulation results confirm analytical derivations and further show the effects of the circuit power, fading duration, and fading severeness on the achievable EE and effective capacity of a delay-limited fading channel.

KW - Energy efficiency

KW - delay-outage probability constraint

KW - effective capacity

KW - fractional programming

KW - Nakagami fading

KW - CAPACITY

KW - SERVICE

KW - QUALITY

KW - REGIME

U2 - 10.1109/TWC.2014.2316808

DO - 10.1109/TWC.2014.2316808

M3 - Journal article

VL - 13

SP - 4081

EP - 4091

JO - IEEE Transactions on Wireless Communications

JF - IEEE Transactions on Wireless Communications

SN - 1536-1276

IS - 8

ER -