Group-based Pilot Design Method in Mobile OFDMA Systems

In mobile communication systems, users move with various speeds. Therefore, pilot designs using the fixed arrangement of pilot subcarriers and channel estimation method are not suitable. In this paper, we propose a group-based pilot design method in mobile orthogonal frequency division multiple access (OFDMA) systems. In the proposed method, we divide users into several groups based on the users' speeds and allocate an appropriate pilot arrangement for each group. Using the proposed method, we minimize the channel estimation errors of high-speed users while maximizing the resource efficiency of low-speed users.