Chaos-based modulation for blind and coherent signal detection in non-cooperative TDD cellular networks with large antenna arrays

摘要

Inter-cell interference is a challenging issue in non-cooperative time-division duplex (TDD) cellular systems with large antenna arrays. In this document we propose two signal detection methods based on Differential chaos-shift-keying (DCSK) modulation that robustly detect individual users in congested networks. Blind signal detection at the BTS is an appropriate technique in systems where channel state information (CSI) in not accurate. A detection technique based in DCSK modulation is presented, this method detects individual users in a cell without knowledge of the channel coefficients. Recently, a training scheme for non-cooperative TDD cellular systems has been proposed in which the transmission of pilots is shifted in time from one cell to the next, avoiding overlap. This method cancels out interference from inter-cell users during the training period and channel state information may be retrieved. Therefore, a DCSK-based coherent detection technique at the BTS is proposed in which a large number of individual users within a loaded cellular system can be detected with low bit-error-rate (BER) levels. Finally, M-ary DCSK modulation is discussed. With this technique, b > 1 bits can be modulated in a single transmission as opposed to conventional DCSK. The M-ary DCSK scheme is tested in Multi-user MIMO systems to increase the spectral efficiency of the chaotic system.