Improve initial ranging for uplink OFDMA systems by partial frequency sequence detection

This paper proposes an improved initial ranging method for orthogonal frequency division multiple access (OFDMA) system. In initial ranging, though the expected timing offset is quite long, the actual channel spread of specific user equipment (UE) is short. In addition, due to bandwidth limitation of ranging sequence, sidelobe appears which degrades the performance of noise detection. By the two characteristics, this paper constructs a ranging scheme including particularly designed ranging symbol and improved partial frequency domain sequence detector. Computer simulation results show that the detection variable is improved, which coincides with the theoretical analysis presented.