Average Energy Efficiency Contours with Multiple Decoding Policies

Abstract

Abstract-This letter addresses energy-efficient design in multiuser, single-carrier uplink channels by employing multiple decoding policies. The comparison metric used in this study is based on average energy efficiency contours, where an optimal rate vector is obtained based on four system targets: Maximum energy efficiency, a trade-off between maximum energy efficiency and rate fairness, achieving energy efficiency target with maximum sum-rate and achieving energy efficiency target with fairness. The transmit power function is approximated using Taylor series expansion, with simulation results demonstrating the achievability of the optimal rate vector, and negligible performance difference in employing this approximation.

Energy Efficiency Contours for Broadcast Channels Using Realistic Power Models

“…where, g = [g 1 , g 2 , ..., g K ] and P max is the maximum transmit power of the BS, and constraint (13) specifies that all rate pairs should be chosen within the BC capacity region. We denote this resource allocation method as EE max .…”

“…Such approaches are more suitable for mobile systems with a single objective, however, when multiple optimality measures are targeted, this approach is less effective. To tackle this, our previous work in [13] introduced EE contours as a novel way of obtaining the optimal operating point of the system based on multiple system requirements for the uplink channel. However, a user-centric EE formulation was given which did not address the EE of the single-cell system as a whole.…”

“…Previous studies on the EE-SE trade-off are based on the sum-rate, which is why further investigation is required in order to obtain deeper insights into this tradeoff. In this regard, we derive the generic equation of the EE contours [13] for the broadcast channel (BC) and utilize them for analyzing and getting insights on the trade-off between EE and SE, with multiple constraints such as fairness and individual rate distribution of users.…”

Energy Efficiency Contours for Single-Carrier Downlink Channels

“…The EE contours in Fig.1 demonstrate one of the most fundamental differences between energy-efficient design in the uplink and downlink, where it was shown in [4] that, maximum EE is achieved in the uplink when, all users transmit simultaneously by employing a successive interference cancellation (SIC) receiver.…”

“…The system EE will be measured using two different decoding policies, where a framework is used to choose the optimal decoding policy for each rate point such that EE is maximized. EE contours which we introduced in [4] will then be used to identify optimal operating points based Manuscript received July 12, 2011. The associate editor coordinating the review of this letter and approving it for publication was G. Mazzini.…”