Interference management and subchannel selection in femtocells

• Main Author: Jagadheesan Vignesh
• Other Authors: Li Kwok Hung
• Format: Theses and Dissertations
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/72541
• Institution: Nanyang Technological University

Femtocells are small, little cost, tiny range and low-power base stations with the intention to deliver a better data connectivity for indoor users. Analogous to a Wi-Fi router, the installation of femtocells is simple. The selection of a subchannel plays a critical role in the wireless communication technology. Care should be taken because of many interference problems arises due to this channel selection. Two methods, namely the best response and the stochastic best response, are suggested in this dissertation. We assume the system to be time slotted. Each femto link senses the signal-to-interference-plus-noise ratio (SINR) of each subchannel. However, the femto links do not exchange the information related to subchannels. Then, the transmission occurs in the subchannel with the highest SINR value. This corresponds to the best response strategy. Due to the simultaneous move in the best response, fluctuation occurs. Fluctuation generally corresponds to the frequent and improper switch between subchannels by any femto link. Total capacity for 3 links 2 subchannels, 5 links 3 subchannels and 7 links 4 subchannels are discussed. The stochastic best response method eliminates the oscillation problem in the best response system. The sequential move replaces the simultaneous move in the new strategy. This sequential move is due to the small transition probability a. Various transition probability values are discussed. With this small transition probability, we obtain the maximum total capacity value. We analyze the performance and verify our simulated results using the Markov chain. We also discuss the heterogeneous case with the amalgamation of femto and macro links in a 5 links 3 subchannels scenario. The study of heterogeneous networks can be extended further.