Is Multichannel Access Useful for Timely Information Update?

This letter investigates information freshness of multichannel access in information update systems. Age of information (AoI) is a performance metric that characterizes information freshness. When multiple devices share the same wireless channel to send updates to a common receiver, an interesting question is whether dividing the whole channel into several subchannels will lead to better AoI performance. Given the same frequency band, dividing it into different numbers of subchannels leads to different transmission times and packet error rates (PER), thus affecting information freshness. We focus on a multichannel system where devices take turns to transmit with a cyclic schedule repeated over time. We derive the average AoI by estimating the PERs of short packets. We further examine bounded AoI, for which the instantaneous AoI is required to be below a threshold a large percentage of the time. Our results indicate that multichannel access can provide low average AoI and uniform bounded AoI simultaneously across different received powers.