Number Of Resolvable Paths Research Articles

Multipath-decorrelating receiver using adaptivepath selection forsynchronous CDMA frequency-selective fading channels

In a conventional multipath-decorrelating receiver, the complexity and noise enhancement increase with the number of resolvable paths. A scheme is proposed that adaptively selects a subset of the paths, reducing both system complexity and noise enhancement. Analytical results are given that show the tradeoff between noise enhancement and multipath-induced multiple access interference for better performance.

Combined multiuser detection and diversity reception for wireless CDMA systems

Code division multiple-access (CDMA) techniques using interference cancellation are being explored for the capacity increase in third-generation universal mobile telecommunications systems. However, multipath fading is a major constraint on the performance of wireless CDMA systems, with multipath propagation worsening the effects of multiple-access interference, and fading on propagation paths leading to the near far problem. Multiuser detection, exploiting the knowledge of other users to cancel multiple-access interference, has the capability of eliminating the near far problem and providing a significant capacity increase in CDMA systems. On the other hand, diversity techniques effectively combat the fading effects of the channel. This paper investigates multiuser receivers that combine explicit antenna diversity, RAKE multipath diversity, and multipath decorrelating detection. Both coherent reception with maximal-ratio combining and differentially coherent reception with equal-gain combining are analyzed. The results demonstrate a significant increase in up-link capacity over the conventional RAKE receiver, at the expense of complexity. In the case of limited receiver complexity, where the number of correlators is less than the number of resolvable paths at the RAKE front-end, antenna diversity is shown to be effective in reducing residual multiple-access interference.

BER performance on multipath fading channels with random path delays

The bit error rate (BER) of trellis coded narrowband 8 PSK of multipath fading channels is found to depend strongly on the path delay differences, because these determine the number of resolvable paths. Assuming uniformly distributed path delays, the average BER is shown to decrease with increasing delay spread. The BER performance can be substantially improved by using spread-spectrum instead of narrowband signalling.