Implementation of a coherent reverse channel 900 MHz CDMA receiver with reference symbols

Abstract

There are many radio access standards contending for attention in the world-wide cellular marketplace. Practical estimator methods and sequences are introduced for the reference symbol based DS-CDMA radio (denoted "RC"). It is a physical layer scheme involving insertion of a known training sequence into the coded, interleaved bit stream for an IS-95-like CDMA reverse channel. This paper presents the principle estimators needed for implementation of an RC receiver, and frame error rate (FER) results for a flat fading channel. The frame error rate or Eb/No required for a 1% FER is given for both idealized and realistic conditions concerning time varying carrier frequency offset and delay slew of the received timing. A comparison to IS-95 shows a 2 dB improvement.