Layered Broadcast/Multicast mechanism for Spectral-efficient 4G wireless networks

By adopting hierarchical modulation, layered broadcast/multicast mechanism is a promising method to achieve spectral efficient transmission for users with diverse fading channels in 4G wireless networks, however, there is a great challenge to determine the optimal modulation parameters in applications due to the varying wireless environment and the technique characteristics. In this work, a Spectral-efficient Layered Broadcast/Multicast (SLBM) mechanism for 4G Wireless networks is proposed to solve this problem in a Rayleigh fading channel. With consideration of both the efficiency and reliability, a spectral efficiency evaluation function is formulated, and to facilitate the decision process of optimal modulation parameters, a modulation solution set for SLBM with multiple layers is defined. Based on the modulation solution set, a layered modulation solution selection algorithm is illustrated to determine the optimal modulation parameters effectively. Numeric analysis is conducted to demonstrate the proposed mechanism with comparison to conventional scheme, and the results demonstrate that SLBM mechanism could yield higher energy efficiency under different bit error rate (BER) targets, while the impact of number of layers is discussed.