  Cell-free massive MIMO provides ubiquitous connectivity for multiple users,
and implementation using radio stripes is very efficient. This paper proposes a
parallel scheme for radio stripes to allow access point to do signal processing
simultaneously. Simple maximum ratio (MR) processing works in this scheme, but
its performance is bad. Therefore, this paper further proposes two efficient
parallel schemes to gain better performance. The first is interference-aware MR
processing with a tailored user-centric strategy. The second is distributed
regularized zero-forcing (D-RZF) algorithm which derives from LMMSE. Simulation
results show that the proposed parallel schemes gain better performance than
existing works.
