Capacity of Linear Decorrelating Detector for QS-CDMA
نویسندگان
چکیده
We study the performance and capacity of a quasi-synchronous code division multiple access (QS-CDMA) cellular system employing the decorrelating detector. It is assumed that each of N users has a GPS generated local clock, and attempts to transmit in synchrony with the other users in its cell. The detector makes use of the small timing uncertainties to build the interference signal space and perfectly cancel the interference. Results are compared with those of an adaptive MSE receiver. It is shown that when the LMS adaptive algorithm is employed the mean-squared-error misadjustment signi cantly a ects the receiver performance. Finally, system capacities in terms of users/cell are evaluated.
منابع مشابه
Reducing the Limitation on Application of Synchronous Decorrelating Detector Cdma Systems
In CDMA (Code - Division Multiple - Access) systems multi - user accessing of a channel is possible. Under the assumptions of Optimum multi - user and decorrelating detector in CDMA systems. By using signals with zero and / or identical cross correlations, a simple and expandable decorrelating detector with optimum efficiency which can be easily implemented are proposed. Constructing these sign...
متن کاملNonlinear 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 کاملImproved CDMA multiuser receivers robust to timing errors
We investigate an improved multiuser detector for asynchronous CDMA uplink channels when there exist timing delay estimation errors. We first formulate a robust decorrelating detector with a capacity limit of 50%. To increase the system capacity, we further propose a robust successive interference cancellation (SIC) implementation. The proposed robust SIC detector adds only a residual error est...
متن کاملThe Impact of Timing Errors on the Performance ofLinear
| In this paper an asynchronous direct-sequence code division multiple access (DS-CDMA) communication system operating over an additive white Gaussian noise (AWGN) channel is considered. In many applications, the near-far problem can be the limiting factor for the capacity of a DS-CDMA system. Several near-far resistant receivers have therefore been proposed (e.g., the decorrelating receiver). ...
متن کاملMultiuser Access Detection for CDMA Systems
We consider CDMA systems employing packet switching where multiple users can access the system simultaneously. The problem of detecting the activity of multiple new users in an efficient manner is studied. Under the optimistic assumption of a discrete delay space,, the maximum likelihood receiver that detects the presence of multiple new users, i.e the optimum multiuser access detector, has hig...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1999