Title :
Convergence of linear interference cancellation multiuser receivers
Author :
Grant, Alex ; Schlegel, Christian
Author_Institution :
Inst. for Telecommun. Res., Univ. of South Australia, SA, Australia
fDate :
10/1/2001 12:00:00 AM
Abstract :
We consider the convergence in norm of several iterative implementations of linear multiuser receivers, under the assumption of long random spreading sequences. We find that asymptotically, linear parallel interference cancellation diverges for systems loads of greater than about 17%. Using known results from the theory of iterative solutions for linear systems we derive optimal or near-optimal relaxation parameters for parallel (first- and second-order stationary, Chebyshev) and serial cancellation (successive relaxation) methods. An analytic comparison of the asymptotic convergence factor for the various methods is given. Simulations are used to verify results for finite size systems
Keywords :
code division multiple access; convergence of numerical methods; interference suppression; iterative methods; multiuser channels; radio receivers; relaxation theory; spread spectrum communication; Chebyshev iteration; asymptotic convergence factor; finite size systems; first-order stationary iteration; iterative implementations; linear multiuser receivers; linear parallel interference cancellation; long random spreading sequences; near-optimal relaxation parameters; optimal relaxation parameters; parallel cancellation methods; second-order stationary iteration; serial cancellation methods; successive relaxation; Chebyshev approximation; Convergence; Decorrelation; Detectors; Gaussian processes; Interference cancellation; Iterative methods; Jacobian matrices; Linear systems; Nonlinear filters;
Journal_Title :
Communications, IEEE Transactions on
