Impairments in Cooperative Mobile Networks: Models, Impact on Performance and Mitigation

Inhalt:
Base station cooperation is a powerful technique for eliminating inter-cell interference and enhancing spectral efficiency in cellular networks. However, impairment effects due to channel estimation, feedback quantization, channel time variance as well as imperfect carrier and sampling frequencies among base stations are limiting the potential gains. This paper provides a unifying framework for modeling these impairments in cooperative multi-user multi-cellular systems, for analyzing the performance degradation due to the resulting inter-user interference and finally for mitigating impairments. Evaluation of the performance degradation reveals how critical impairments are. Multi-cell channel estimation, clustering and feedback compression are investigated as mitigation tools, while it is shown that advanced channel prediction and synchronization of distributed base stations can also compensate the performance degradation. In this way, limitations in mobility, feedback delay and number of supported users can be relaxed, which makes base station cooperation a practical and highly attractive technique.