This paper proposes an encoding/decoding framework for achieving the optimal channel capacity of the two-user broadcast channel where each user has message targeted for the other user as side information. Since the link qualities of the channels from the base station to users are different, the channel capacities are different. This fact implies different data rates for different users. For this scenario, the network coding technique can be employed to improve the transmission efficiency. However, how to simultaneously achieve the channel capacities for the two users is not straightforward. This problem is referred to as the rate-diverse wireless network coding problem. In this paper, we present a capacity-achieving framework based on linear structured nested lattice codes for rate-diverse wireless network coding. The significance of the proposed framework, besides its theoretical optimality, is its suggested design principle for linear rate-diverse wireless network coding.
['Taotao Wang', 'Soung Chang Liew', 'Long Shi']
A Lattice Approach for Optimal Rate-Diverse Wireless Network Coding