Optimum delay-rate tradeoff in Ergodic Interference Alignment

In this paper, we consider one of the main disadvantages of Ergodic Interference Alignment, i.e., delay. We propose two methods to solve the open problem of finding the best choice of user sets in order to minimize the delay. With these methods we are able to find the best JAP-B scheme which aims to trade off rate for delay in Ergodic Interference Alignment. First, we provide the solution based on the trellis structure and Viterbi algorithm. Observation and analysis of the result of this method for the different networks lead to the second proposed solution. With this method, the computation complexity reduces to the substitution of the network's parameters in a closed form equation and is independent of the network size. The local optimality of this solution is also proved.