A hierarchical MADM-based network selection scheme for system performance enhancement

In a heterogeneous wireless network consisting of macrocells and femtocells, it is important for mobile terminals to decide appropriate cell associations when both radio access technologies (RATs) are available. This problem is also known as network selection. Nowadays mobile users are distinct in terms of quality of service (QoS) demand, moving speed and other service preferences, while the conventional maximum signal-to-interference-plus-noise-ratio (SINR) based cell association schemes are not able to jointly consider these different requirements. In this paper, we propose a hierarchical cell association algorithm based on the multiple attribute decision making (MADM) method but with a simplified process and fewer carefully chosen attributes to lower computational complexity. The performance in terms of user´s average wideband SINR, spectral efficiency and load balance is evaluated through simulations. The results show that the average wideband SINR and spectral efficiency are improved for 60%-80% of users as compared to the max-SINR scheme. Load balancing is also achieved.