Pilot signaling for multi-cell OFDMA uplink systems

OFDMA is considered as one of the major candidates for broadband wireless access. The OFDMA signal is usually coherently demodulated, requiring the channel estimation which can be estimated using a known pilot signal. In multicell environment, the performance of channel estimation is mainly limited by intercell interference. It is desirable to use a pilot signal that can estimate the channel information robust to the intercell interference in the OFDMA uplink system. In this paper, we consider two types of pilot signal applicable to multi-cell OFDMA uplink systems: One is time-multiplexed pilot signal and the other is codemultiplexed pilot signal. Simulation results show that the code-multiplexed pilot is suitable for low mobility environment and time-multiplexed pilot is suitable for high mobility environment.