Efficient parallel data retrieval in MIMO wireless data broadcast with replicated data items

Data retrieval problem is a novel research direction about wireless data broadcast. The goal is to find an efficient sequence to download the requested information from public information in wireless communication. The types of data items broadcast in channel are followed: consecutive and no replicated, non-consecutive and no replicated, and nonconsecutive and replicated. The goal of above types is to reduce the energy consumption, but the complexity is introduced. In order to reduce the complexity of wireless data broadcast with non-consecutive and replicated data items, we define MIMO parallel data retrieval problem with replicated data items and prove that it is NP-hard. In this paper, we also design two heuristic algorithms for data retrieval problem in MIMO and MISO wireless data broadcast. The experiment results show that the proposed schemes have better performance in the case of less requested data items.