Message Passing Based Activity Detection in Distributed Massive MIMO With Pilot-Hopping and Activity Correlation

Abstract

Orthogonal-pilot-hopping transmission is an efficient random access scheme since the orthogonal pilot can aid the activity detection (AD) and channel estimation. Moreover, in many scenarios, the activity of devices is correlated, e.g., devices are used to monitor the same physical phenomenon. In this correspondence, we study the AD in distributed massive multiple-input multiple-output with pilot-hopping and activity correlation. Specifically, the hybrid generalized approximate message passing based AD is proposed. In the proposed method, the position of event is first quantized, and thus the activity correlation can be presented by the probability related with the distance between the device and quantized event. Next, the message update rule for the check node presenting the activity correlation is derived. Finally, computer simulations are given to demonstrate the effectiveness of the proposed method.