Modified PN code tracking loop for direct-sequence spread-spectrum communication over arbitrarily correlated multipath fading channels

A modified PN code tracking loop for direct-sequence spread-spectrum communication over arbitrarily correlated multipath fading channels providing a fully digital, non-coherent, modified code tracking loop, being able to operate on bandlimited DS/SS systems over frequency-selective fading channels, said modified code tracking loop, assisted by central-branch correlation, embedded into a RAKE receiver in a proposed technique, by taking advantage of central-branch correlation, an error characteristic obtained on each RAKE finger being able to be kept within one chip duration;

• thus, a kind of self-interference encountered in previous works being able to be effectively reduced, by exploiting inherent diversity using maximum ratio combining (MRC) and multipath interference cancellation (MPIC), said proposed technique being able to avoid unsteadiness in locked points of error signals and, thus, providing an improved error characteristic, it being proven that said error signals obtained using said proposed technique are definitely odd-symmetric with respect to a common locked point over arbitrarily correlated multipath fading channels;
• furthermore, very attractive improvements obtained using said proposed technique in terms of timing jitter and mean time to lose lock (MTLL) being verified here.