Adaptive distributed detection scheme in collaborative multiple-input multiple-output systems

This paper proposes adaptive distributed detection schemes for terminal-collaborative multiple-input multiple-output (MIMO) systems, in which multiple wireless terminals jointly receive MIMO signals transmitted from a base station. To reduce collaboration traffic while maintaining transmission performance, an on-demand multiple detection terminals scheme is introduced, where detection terminals evaluate the reliability of their decision results and selectively request more reliable decisions from peer terminals within the collaboration group. Building on this, an on-demand adaptive multiple detection terminals (OAMDT) scheme is proposed, wherein detection terminals dynamically assume the role of helper terminals to forward their received signal waveforms when additional diversity is needed due to persistent decision errors. Both schemes employ frequency-domain iterative equalization using MMSE filtering and LDPC decoding, and utilize a residual error coefficient as a reliability metric to guide decision fusion and adaptive role assignment. Simulation results under various fading environments and SNR conditions demonstrate that while the on-demand multiple detection terminals scheme effectively reduces traffic overhead, the OAMDT scheme significantly enhances packet error rate performance with only a modest increase in collaboration traffic. The results further reveal diminishing returns in error performance when increasing the number of detection terminals, suggesting that adaptive role switching is particularly beneficial under constrained conditions such as overloaded MIMO scenarios. These findings indicate that the proposed adaptive collaboration mechanisms can enhance the efficiency and robustness of terminal-collaborated MIMO reception.