Toward Reliable Communications With Delay Requirement in Aerial Disaster Emergency Networks via Coordinated Multi-Point

Coordinated multi-point (CoMP) is a promising technique to ensure timely and reliable communications. However, flying access point (FAP) CoMP in aerial disaster emergency networks (ADENs) relies on wireless fronthaul, which is unreliable due to performance loss compared to wired fronthaul. Moreover, FAP movement and the existence of no-fly regions (NFRs) may cause dynamic transmission distances between ground users (GUs) and FAPs. Thus, how to robustly ensure timely and reliable communications via FAP CoMP is an urgent problem in ADENs. In this paper, we introduce wireless-fronthaul-effective-factor (WFEF) to reflect the unreliability of FAP CoMP and analyze network availability (NA), which is defined as the probability that delay and reliability requirements of each GU are satisfied. Through analysis, we first reveal WFEF constraints that prevent CoMP from underperforming non-CoMP. Then, given <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> GUs served by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> FAPs over the same time-frequency resource, we provide condition <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C : P^(L−K+1)</i> ≫ 1 to ensure timely and reliable communications, where P is a function of system parameters including WFEF and NFRs, etc., and delay and reliability requirements. Finally, we derive that adopting <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> = [<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i>/2] alleviates NA degradation due to NFRs by balancing the bandwidth of GUs with spatial diversity and multiplexing gains of CoMP, which enhances the robustness of ADENs.