Book Chapter

Robust RLS Adaptive Algorithms

Elnashar, Ayman

2018

Overview

This chapter develops and implements linearly constrained IQRD‐recursive least squares (RLS) algorithms with multiple constraints for multiuser detection (MUD) in DS/CDMA systems. In the conventional RLS algorithm, the calculation of the Kalman gain requires inversion of the autocovariance matrix of the received signal. The IQRD algorithm acts as a core to the proposed receivers, which facilitates real‐time implementation through systolic implementation. Systolic array implementation of IQRD‐based algorithms has important merits. The chapter considers two approaches: with a constant constrained vector and with an optimized constrained vector. It also implements the channel estimation techniques in adaptive fashion based on the IQRD‐RLS algorithm. Consolidating the channel estimation and the quadratic constraint technique gives an extremely robust detector, especially at low signal‐to‐noise ratios (SNR). Quadratic inequality (QI) constraint value could be selected based on some preliminary knowledge about wireless channels or using a Monte Carlo simulation.

• Publisher: John Wiley & Sons, Incorporated,John Wiley & Sons, Ltd
• Subject: channel estimation techniques / constant constrained vector / IQRD-RLS algorithm / Monte Carlo simulation / multiuser detection / optimized constrained vector / systolic array implementation
• ISBN: 1118938240, 9781118938249