SC-FDE and OFDM Hardware Efficient Dual Mode Transceiver For IEEE 802.16a BWA System
Date Issued
2004
Date
2004
Author(s)
Chen, Tzu-Ying
DOI
en-US
Abstract
Among all applications in the global information village, wireless network plays an important role, and broadband wireless access can provide more capacity than its wired broadband counterparts by extending fiber optic networks to the airwaves. Therefore, this thesis proposes the architectures of baseband transceivers comply with IEEE 802.16a of wireless MAN.
The single carrier modulation exploiting the frequency domain equalization makes it a potentially valuable alternate to OFDM. The similarity and the differences between OFDM and SC-FDE are discussed and compared. A dual-mode system combining individual advantages of OFDM and SC-FDE is chosen for investigation and design.
The regulated packet format which is adjustable on different transmission conditions and requirements of users can be delivered by the dual-mode transmitters. The receivers have the capability to overwhelm many kinds of degradations due to non-ideal transmission environments. With the aid of the delay correlator and matched filter, the symbol boundary synchronization can be achieved. Furthermore, a carrier recovery scheme utilizing the characteristics of the preamble is proposed to conquer the limitation of the estimation range for the original correlator. In addition, because of the variable length of the guard interval, an auto-detection and removal mechanism is proposed to both systems. Combining the modified interpolator with a sliding window, an all digital timing recovery scheme is implemented in a non-synchronized sampling way. The frequency domain equalizer for the OFDM system performs the channel estimation and equalization by ZF and LMS algorithms. As to SC system mode, two kinds of frequency domain equalization with linear type and decision feedback type are compared. Furthermore, the FFT module utilizes the algorithm of radix-2/4/8 and the single-path delay feedback architecture.
These circuit designs are based on the technique of hardware sharing. The degree of the efficiency for hardware reuse that depends on the different architectures of frequency domain equalizer for SC will be discussed. Finally, a VLSI coexistent baseband transceiver is implemented.
Subjects
傳收機
單一載波
正交分頻多工調變
寬頻無線接取系統
SC-FDE
IEEE 802.16a
OFDM
Transceiver
Type
thesis
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