Multiuser detection of asynchronous CDMA with frequency offset
نویسندگان
چکیده
This letter presents a near–far resistant detection scheme for asynchronous code-division multiple access with frequency offset. Based on a one-shot technique and Taylor expansion, a zeroth-order and a first-order one-shot linear decorreating detector (LDD) are proposed. The zeroth-order LDD has simple architecture but suffers performance degradation for large frequency offset. The first-order one-shot LDD, with increased complexity, has very good near–far resistant property even for large frequency offset. Two versions of the first-order one-shot LDD are investigated according to different Taylor expansion approaches. The feasibility of the proposed detectors is demonstrated by computer simulations.
منابع مشابه
Nonlinear Multiuser Receiver for Optimized Chaos-Based DS-CDMA Systems
Chaos based communications have drawn increasing attention over the past years. Chaotic signals are derived from non-linear dynamic systems. They are aperiodic, broadband and deterministic signals that appear random in the time domain. Because of these properties, chaotic signals have been proposed to generate spreading sequences for wide-band secure communication recently. Like conventional DS...
متن کاملA Novel Scheme for Linear Multiuser Detection in Asynchronous Ds-cdma Systems with Frequency Selective Fading
A novel scheme for linear Multiuser Detection (MUD) based on Sub-Symbol diversity is presented that is applicable to Asynchronous CDMA systems with frequency selective fading. Traditional solutions for asynchronous linear MUD result in a prohibitively large decorrelation matrix. The new scheme transforms the asynchronous problem into a synchronous one by creating sub-symbols that are, by design...
متن کاملSubspace adaptive detection for asynchronous multiuser CDMA with frequency domain channel response and delay estimation
Channel estimation, particularly delay estimation in asynchronous CDMA channel, is essential for most receivers. The correlated time domain data sequence will become asymptotically uncorrelated in frequency domain. By taking Discrete Fourier Transform (DFT) of the received signals, we can take advantage of this asymptotical property to simplify the estimation algorithm. The proposed scheme can ...
متن کاملFrequency-domain approach to DS-CDMA multiuser detection over frequency-selective slowly fading channels
By extending the frequency-domain approach [1] to practical scenarios such as the frequency-selective slowly fading channels, we justify the value of our proposed frequency-domain approach to multiuser detection in the DS-CDMA communications systems. With this frequencydomain approach which maintains the frequency-domain orthogonality between different users, the DS-CDMA communication is MAI-fr...
متن کاملPerformance Comparison of Sphere Decoding and Global Search Algorithm based Multiuser Detectors for MC-CDMA System under Clipping Noise
Multi Carrier Code Division Multiple Access (MC-CDMA), a promising technology for the 4G communication systems is considered in this paper. The foremost limitation of such system is the Multiple Access Interference (MAI) which is due to frequency-selective fading, near-far effect, frequency offset, and nonlinear power amplification due to clipping noise. The performance of MC-CDMA under such sc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- IEEE Trans. Communications
دوره 49 شماره
صفحات -
تاریخ انتشار 2001