To Decode the Interference or To Consider it as Noise

TL;DR

This paper proposes a decoding strategy for channels with multiple interfering users, allowing the receiver to decode some interferers and treat others as noise, achieving the channel's capacity with an efficient algorithm.

Contribution

It introduces a method to partition interfering users into decodable and non-decodable sets, optimizing achievable rates and providing a polynomial-time algorithm for maximum decodable subset detection.

Findings

Gaussian distribution is optimal for the additive Gaussian channel with interference.

The proposed method achieves the channel capacity.

An efficient polynomial-time algorithm finds the maximum decodable set.

Abstract

We address single-user data transmission over a channel where the received signal incurs interference from a finite number of users (interfering users) that use single codebooks for transmitting their own messages. The receiver, however, is allowed to decode interfering users' messages. This means the signal transmitted from any interfering user is either decoded or considered as noise at the receiver side. We propose the following method to obtain an achievable rate for this channel. Assuming its own data is decoded successfully, the receiver partitions the set of interfering users into two disjoint subsets, namely the set of decodable users and the set of non-decodable users. Then the transmitter's rate is chosen such that the intended signal can be jointly decoded with the set of decodable users. To show the strength of this method, we prove that for the additive Gaussian channel with Gaussian interfering users, the Gaussian distribution is optimal and the achievable rate is the capacity of this channel. To obtain the maximum achievable rate, one needs to find the maximum decodable subset of interfering users. Due to the large number of possible choices, having efficient algorithms that find the set of decodable users with maximum cardinality is desired. To this end, we propose an algorithm that enables the receiver to accomplish this task in polynomial time.