Reverse-link macrodiversity in CDMa distributed antenna systems with imperfect channel estimation

The performance of reverse-link macrodiversity in CDMA distributed antenna (DA) systems with imperfect channel estimation is analyzed by taking the effect of multi-path fading environment into account. A detailed multi-access model with MRC-based multi-path micro diversity and multi-antenna macrodiversity is presented and exact reverse-link E _b/I₀ expression is derived. The investigation shows that when multipath fading and channel estimation errors occur, for the reverse-link of CDMA DA systems, the E_b/I₀ performance degrades and the macrodiversity gains diminish more rapidly in comparison with the results obtained based on the ideal assumption. Furthermore, it is shown that, on the reverse-link, the conventional solution recommended in most of previous studies that the number of remote antennas per "virtual cell" set to four is no longer cost-effective in such an imperfect environment