Optimal Resource Allocation for Power-Efficient MC-NOMA with Imperfect Channel State Information

TL;DR

This paper develops an optimal resource allocation framework for MC-NOMA systems considering imperfect channel information, aiming to minimize power consumption while satisfying user QoS, and proposes a suboptimal algorithm with near-optimal performance.

Contribution

It introduces a globally optimal resource allocation method for MC-NOMA with imperfect CSIT and proposes a practical suboptimal algorithm balancing performance and complexity.

Findings

Suboptimal scheme achieves near-optimal power savings.

Both schemes outperform conventional OMA in power efficiency.

Optimal solution serves as a benchmark for system performance.

Abstract

In this paper, we study power-efficient resource allocation for multicarrier non-orthogonal multiple access (MC-NOMA) systems. The resource allocation algorithm design is formulated as a non-convex optimization problem which jointly designs the power allocation, rate allocation, user scheduling, and successive interference cancellation (SIC) decoding policy for minimizing the total transmit power. The proposed framework takes into account the imperfection of channel state information at transmitter (CSIT) and quality of service (QoS) requirements of users. To facilitate the design of optimal SIC decoding policy on each subcarrier, we define a channel-to-noise ratio outage threshold. Subsequently, the considered non-convex optimization problem is recast as a generalized linear multiplicative programming problem, for which a globally optimal solution is obtained via employing the branch-and-bound approach. The optimal resource allocation policy serves as a system performance benchmark due to its high computational complexity. To strike a balance between system performance and computational complexity, we propose a suboptimal iterative resource allocation algorithm based on difference of convex programming. Simulation results demonstrate that the suboptimal scheme achieves a close-to-optimal performance. Also, both proposed schemes provide significant transmit power savings than that of conventional orthogonal multiple access (OMA) schemes.