Browsing by Author "Tang, CH"

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Pilot channel aided adaptable interference cancellation scheme for uplink DS/CDMA mobile radio systems
(2001)
Tang, CH
;
Chang, WY
;
Wei, CH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a pilot channel aided adaptable interference cancellation (IC) scheme which combines serial (SIC) and parallel (PIC) interference cancellation to adapt to different services under different circumstances for uplink wideband DS/CDMA system. The processing delay and computational complexity can be adjusted based on system loading and required performance. The interference between data channel signals and pilot channel signals under multipath fading channel are also taken into consideration. This results in better quality both on channel parameter estimation and user data detection. Compared with SIC and PIC, the proposed scheme shows better performance with reasonable hardware while it needs shorter processing delay than SIC.
Pilot-channel aided pipeline scheme for interference cancellation in uplink DS/CDMA system
(2002)
Tang, CH
;
Wei, CH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a pilot-channel aided pipeline scheme for interference cancellation (IC) in uplink wideband DS/CDMA system. Generally speaking, pipelined implementation is inherent in SIC but not in channel estimation. This scheme combines channel estimation and user data detection into sequential type with low complexity and leads to pipeline implementation. Besides, interference between data channel signals and pilot channel signals under multipath fading channel are also taken into consideration. Compared with conventional channel estimation using correlator output and SIC without pilot signal remover, the proposed scheme shows better quality both on channel estimation and user data detection.
Pilot-channel aided SIC scheme for multirate WCDMA systems in multipath fading channels
(2005)
Tang, CH
;
Wei, CH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A generalized pilot-channel aided successive interference cancellation (SIC) scheme is presented to apply to multirate communications in uplink WCDMA systems over multipath Rayleigh fading channels. The scheme performs data detection in a group manner for each user, and the cancellation order is decided based on the average RAKE output strength over the grouping interval at the first stage of SIC. The grouping detection method help the users with relatively large spreading gain to perform much better at the expense of slight performance loss of the user with the lowest spreading gain. In addition to showing that the optimal grouping interval for high rate users depends on the Doppler shift of Rayleigh fading channel, the BERs of individual spreading gain are compared with those in the single rate system.
Pilot-channel aided successive interference cancellation for uplink WCDMA systems over multipath fading channels
(2004)
Tang, CH
;
Wei, CH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we examine the performance of the pilot-channel aided successive interference cancellation scheme in asynchronous WCDMA systems over multipath fading channels. Three types of cancellation method are compared where the cancellation order is decided based on either average power or instantaneous measured received signal strength with various updating rate. The scheme performs pilot-channel signal removal before data detection to alleviate the interferences from other users' pilot channels and thus can achieve better performance on user data detection. With the investigation and comparison through computer simulations, the scheme with three types of ordering method are shown to perform variously due to different grouping interval and power distribution ratio over both AWGN and Rayleigh fading channels.