Impact of Multi-connectivity on Channel Capacity and Outage Probability in Wireless Networks

Multi-connectivity facilitates higher throughput, shorter delay, and lower outage probability for a user in a wireless network. Considering these promises, a rationale policy for a network operator would be to implement multi-connectivity for all of its users. In this paper, we investigate whether the promises of multi-connectivity also hold in such a setting where all users of a network are connected through multiple links in the downlink. In particular, we consider a wireless network where every user connects to its <inline-formula><tex-math notation="LaTeX">$k$</tex-math></inline-formula> closest base stations. Using a framework of stochastic geometry and probability theory, we obtain analytic expressions for per-user throughput and outage probability of <inline-formula><tex-math notation="LaTeX">$k$</tex-math></inline-formula>-connectivity networks under several failure models. In contrast to the conclusions of previous research, our analysis shows that per-user throughput always decreases with increasing <inline-formula><tex-math notation="LaTeX">$k$</tex-math></inline-formula>. However, multi-connected networks are more resilient against failures than single connected networks as reflected with lower outage probability. Moreover, multi-connectivity leads to higher throughput fairness among the users. Consequently, we conclude that rather than implementing multi-connectivity for all users, a network operator should consider it for the users who would benefit from additional links the most, e.g., cell edge users.