IDMA Based Inter-cell Interference Cancellation For LTE System

The mobile communication technology is developing rapidly, and has experienced threegeneration communication systems since its birth. Now has launched the3G Long TermEvolution (LTE). LTE uses OFDMA multiple access, which will lead to a serious inter-cellinterference and result in system performance degradation, and it is particularly serious at thecell edge. To address this issue, LTE had a lot of interference suppression scheme.IDMA-based inter-cell interference cancellation is one of the effective interferencesuppression. IDMA is a multi-access technology proposed by Professor Li Ping of the CityUniversity of Hong Kong. IDMA uses interleave patterns distinguish between users and usesan iterative method for multi-user detection.On the basis of analysis of the traditional IDMA technology, this paper presents animproved IDMA algorithm is applied to LTE inter-cell interference cancellation. The newalgorithm is closer to practical applications, and also reflects the better performance. In thispaper we group the interfering BSs into strong-interfering BSs and weak-interfering BSs. Theinterfering signals from weak-interfering BSs are considered as Gaussian noise. Theinterfering signals from strong-interfering BSs are simultaneously detected and suppressedbased on the principles of the IDMA scheme. And in other to meet high-level QAMmodulation and complex channel conditions in LTE, the new algorithm continue to make acorrection. LTE systems commonly used channel estimation algorithms cannot meet therequirements of IDMA multi-user detection, so in this paper, we use the combination ofIDMA system channel estimation EM algorithm and LTE channel estimation interpolationmethod to achieve channel estimation, And the impact of channel estimation error is analyzed.