Performance Evaluation of Coherent High-Speed TD-OFCDM Broadband Packet Wireless Access in Forward Link Employing Multi-Level Modulation and Hybrid ARQ

摘要

This paper evaluates high-speed broadband packet wireless access in the forward link using coherent Time Division-Orthogonal Frequency and Code Division Multiplex- ing (TD-OFCDM) by applying time-multiplexed pilot symbol assisted channel estimation and integrating efficient multi-level modulation, hybrid automatic repeat request (ARQ), and code- multiplexing over a 50-100 MHz bandwidth. Computer simula- tion results first clarify that the common time-multiplexed pilot symbols with the transmit power of 6dB higher than that of data symbols should be placed at both the beginning and end of a packet, and that the optimum averaging interval of channel esti- mates in the frequency domain is different according to the delay spread of a channel.