Browsing by Author "Kao, Shiang-Lun"

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A low-complexity channel-estimation method for IEEE 802.16e systems
(2007)
Wu, Wen-Rong
;
Lin, Wan-Yi
;
Kao, Shiang-Lun
;
電信工程研究所
;
Institute of Communications Engineering
In wireless communication, the channel response may vary rapidly when the user's mobility is high. Since pilot signals are usually limited, channel estimation often involves interpolation. How to perform channel interpolation/estimation in high-mobility scenario is then a challenge problem. This is particularly true for an OFDM system operated in long-delay-profile channels. In this paper, we consider the channel estimation problem in IEEE802.16e systems. Using the special Structure defined in the system, we propose an effective channel estimation algorithm. The main idea is to perform a two-dimensional interpolation with a cascade of two one-dimensional interpolations, one is linear and the other is nonlinear. Simulations show that this method has good performance while its computational complexity is low.
Method and Apparatus for Deciding a Channel Impulse Response
(2009-04-30)
Wu, Wen-Rong
;
Kao, Shiang-Lun
Method and apparatus for deciding a channel impulse response for an OFDM system are provided. First, a channel frequency response is generated by using a plurality of pilot tones of a signal. A channel impulse response is generated by applying the IFFT to the channel frequency response. A plurality of selected channel taps are derived by comparing a plurality of channel taps related to the channel impulse response with a reference threshold. Finally, the channel impulse response is generated by calculating channel impulse respose according to the selected channel taps. This method calculates the channel impulse response in time domain and frequency domain so that the calculation complexity can be reduced, and the system efficiency can be enhanced.