Analysis of Intersymbol Interference Characterized by the Large Array Antennas Adopted in a 60-GHz-Band Gigabit Compact-Range Wireless Access System

A compact-range wireless access system in the 60-GHz band has been proposed for multi-Gb/s data transfer. A prototype Gigabit Access Transponder Equipment (GATE) was built to evaluate the system performance in terms of received signal strength, signal-to-noise ratio (SNR), and bit error rate (BER). The proposed system operates in the near-field regions of large array antennas adopted in the transmitter (Tx). The time delays due to the signals transmitted from different array elements to the receiver (Rx), or/and those due to the multiple reflections between Tx and Rx antennas become comparable with the symbol lengths in our gigabit wireless access system. In that sense, this system would be susceptible to intersymbol interference (ISI). In this study, the concept of ISI is introduced in the antenna field for the first time. An equivalent baseband communication system is newly proposed to evaluate the wireless channel, including Tx and Rx antennas. The analysis procedures and equations are provided for the calculation of ISI. The ISIs due to three potential contributions are analyzed in detail. It is verified that our proposed ISI analysis has succeeded in relating the antenna characteristic to the system performance observed in the baseband.