Low-Latency Heterogeneous Networks with Millimeter-Wave Communications

The heterogeneous network (HetNet) is a key enabler to largely boost network coverage and capacity in the forthcoming 5G and beyond. To support the explosively growing mobile data volumes, wireless communications with millimeter- wave (mmWave) radios have attracted massive attention, and is widely considered as a promising candidate in 5G HetNets. In this article, we give an overview on the end-to-end latency of HetNets with mmWave communications. In general, it is rather challenging to formulate and optimize the delay problem with buffers in mmWave communications, since conventional graph-based network optimization techniques are not applicable when queues are considered. Toward this end, we develop an adaptive low-latency strategy, which uses cooperative networking to reduce the end-to-end latency. Then we evaluate the performance of the introduced strategy. Results reveal the importance of proper cooperative networking in reducing the end-toend latency. In addition, we have identified several challenges in future research for low-latency mmWave HetNets.