Energy Efficient OFDMA Networks Maintaining Statistical QoS Guarantees for Delay-Sensitive Traffic

• Published in: IEEE access Vol. 4; pp. 774 - 791
• Main Authors: Abrao, Taufik, Dias Hiera Sampaio, Lucas, Shaoshi Yang, Cheung, Kent Tsz Kan, Etienne Jeszensky, Paul Jean, Hanzo, Lajos
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5G mobile communication; Algorithm and design analysis; Algorithms; Circuits; Data links; Decay rate; delay-sensitive traffic; Delays; Dinkelbach's method; Downlink; effective capacity; effective energy-efficiency (EEE); Energy conversion efficiency; Energy efficiency; Iterative methods; Mathematical programming; OFDM; Optimization; Orthogonal Frequency Division Multiplexing; orthogonal frequency-division multiple-access (OFDMA); Power amplifiers; Quality of service; Quality of service architectures; Resource allocation; Sensitive traffic; statistical quality-of-service (QoS); Throughput; Traffic delay; Traffic flow; delay-sensitive traffic; effective capacity; 5G; statistical quality-of-service (QoS); orthogonal frequency-division multiple-access (OFDMA); effective energy-efficiency (EEE); Dinkelbach’s method
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2016.2530688

An energy-efficient design is proposed under specific statistical quality-of-service (QoS) guarantees for delay-sensitive traffic in the downlink orthogonal frequency-division multiple-access networks. This design is based on Wu's effective capacity (EC) concept, which characterizes the maximum throughput of a system subject to statistical delay-QoS requirements at the data-link layer. In the particular context considered, our main contributions consist of quantifying the effective energy-efficiency (EEE)-versus-EC tradeoff and characterizing the delay-sensitive traffic as a function of the QoS-exponent θ, which expresses the exponential decay rate of the delay-QoS violation probabilities. Upon exploiting the properties of fractional programming, the originally quasi-concave EEE optimization problem having a fractional form is transformed into a subtractive optimization problem by applying Dinkelbach's method. As a result, an iterative inner-outer loop-based resource allocation algorithm is conceived for efficiently solving the transformed EEE optimization problem. Our simulation results demonstrate that the proposed scheme converges within a few Dinkelbach algorithm's iterations to the desired solution accuracy. Furthermore, the impact of the circuitry power, the QoS-exponent, and the power amplifier inefficiency is characterized numerically. These results reveal that the optimally allocated power maximizing the EEE decays exponentially with respect to both the circuitry power and the QoS-exponent, while decaying linearly with respect to the power amplifier inefficiency.