Novel frequency and time domain method for efficient uplink ranging in cellular ofdma

We address initial ranging process in OFDMA system such as IEEE 802.16e. The proposed ranging method includes two main tasks multi-user ranging code detection and timing estimation. The multi-user ranging code is detected based on a time domain channel (impulse response) detection corresponding to each ranging user through a correlation process that can be performed efficiently in the frequency domain. For initial ranging users, the timing offset also needs to be extracted, which is straightforward after channel is estimated in the process. The simplicity and the efficiency of the proposed method are demonstrated through computer simulation studies. © 2007 by the IETE.