A Simple Superposition Coding Scheme for Optimizing Resource Allocation in Downlink OFDMA Systems

作者：Najeh Sameh; Be**es Hichem^*

来源：Wireless Personal Communications, 2011, 59(2): 237-260.

DOI：10.1007/s11277-009-9915-9

• OFDMA system
• Superposition coding
• Buffer overflow
• Fairness

In this paper, we propose to apply a simple superposition coding strategy for downlink of OFDMA systems. The novelty of this paper consists on allowing at most two users to share the same subchannel. The main idea is to consider the subchannels allocated to the users with the weakest link, and allow these subchannels to be shared by some potential users who can transmit some number of bits with only a small amount of power. To decrease the overhead of the proposed OFDMA system, we restrict to use a predetermined superposition encoding|decoding scheme. We address the problem of resource allocation, which consists on finding the optimal subchannel assignment in the OFDMA system. A low complexity algorithm, denoted Share Specific Subcarrier Allocation (SSSA) is then proposed. It offers a fairness allocation among users. This can be done by taking into account all user's buffer states information. Simulation results confirm that the proposed technique outperforms the classical algorithms in terms of total throughput and dropping probability.

• 出版日期2011-7