Enhancing information freshness for coordinated direct and relay transmission

This paper investigates the information freshness of relay-aided status updating in coordinated direct and relay transmission (CDRT) for first time. Information is measured by age (AoI), defined as time elapsed since generation last successfully received update packet. In CDRT, one sensor communicates directly with receiver while another requires assistance a decode- and-forward relay. Conventional CDRT achieved via division multiple access (TDMA) or non-orthogonal (NOMA). Interestingly, our experiments on software-defined radios (SDR) indicate that error-prone wireless networks, TDMA-CDRT NOMA-CDRT are not superior to each other terms peak AoI all signal-to-noise ratio (SNR) regimes. Specifically, prefers TDMA-CDRT, leading dilemma optimizing system. To this end, we put forth hybrid scheme combines TDMA NOMA. The SDR experimental results show only balances sensors, but also achieves better whole