SOURCE IEEE GLOBECOM 2018,
Abstract—In this paper, the wireless uplink is considered for status update with a large number of terminals. Thy key problem we address is that whether spatial multiplexing of multiple terminals, enabled by the massive multiple-input multiple-output technology, can help to improve the scaling law of age-ofinformation
versus the number of terminals, on account of the mandatory pilot overhead. Based on a queuing theory analysis, we show that the proposed elastic spatial multiplexing scheme, which assigns an optimized pilot length that is smaller than the number of transmitting terminals on account of random packet arrivals, can indeed improve the scaling law compared with the optimal scaling law without spatial multiplexing, by a factor that is related to the packet lengths and arrival rates. Simulation results are provided to validate our findings.