Complexity-Efficient Enumeration Techniques for Soft-Input, Soft-Output Sphere Decoding

TL;DR

This paper introduces two modified soft sphere decoding techniques for iterative MIMO systems that reduce computational complexity by eliminating the full enumeration and sorting process, maintaining performance while improving efficiency.

Contribution

The paper proposes two novel soft sphere decoder modifications that avoid full enumeration and sorting, enhancing computational efficiency without sacrificing max-log performance.

Findings

Modified decoders reduce complexity compared to traditional methods.

They avoid full enumeration and sorting during tree traversal.

Despite more expanded nodes, they are more computationally efficient.

Abstract

In this paper two complexity efficient soft sphere-decoder modifications are proposed for computing the max-log LLR values in iterative MIMO systems, which avoid the costly, typically needed, full enumeration and sorting (FES) procedure during the tree traversal without compromising the max-log performance. It is shown that despite the resulting increase in the number of expanded nodes, they can be more computationally efficient than the typical soft sphere decoders by avoiding the unnecessary complexity of FES.