The main theme of this dissertation is the design of channel contention scheme in frequency domain using orthogonal frequency-division multiplexing (OFDM) subcarrier. It focuses on reducing the overhead of channel contention in time domain. It also focuses on increasing the number of stations (STAs) which transmit a data with single channel contention.
The proposed channel contention scheme consists of two rounds. In the first round, STAs and an access point (AP), which have a data to transmit, select a random subcarrier number. In the second round, the AP broadcasts the information of each subcarrier.
In the first round, a novel collision detection method is proposed. Since the first round symbol has no information about STA identification (ID), the proposed method should be used. It can detect the collision in subcarrier with high probability.
Mathematical analysis and simulation using MATLAB are used to evaluate the performance of proposed scheme. As a result of the analysis, it is confirmed that the results of the mathematical analysis are very closed to those of simbultion. Specially, the performance of the proposed scheme is improved as the number of subcarriers, data rate, and bits per symbol increase.
