Mobility‑Driven Association Policies for Dense Wireless Networks

Abstract

The primary approach to increase coverage and capacity
in infrastructure-based wireless networks is densification. Densification,
however, presents a major challenge when serving mobile users,
which is the overhead associated with the increased rate of base station
handovers. Assuming a prior knowledge of a mobile’s trajectory and
base stations’ locations, we formulate the problem of determining the
sequence of handovers that optimize the trade-off between the mobile
user’s perceived throughput and handover overheads in noise-limited
environments. Under appropriate conditions, we show that the problem
reduces to determining a maximum weight path in a directed acyclic
graph induced by the mobile user’s trajectory. In practice, knowledge of
a mobiles’ trajectory may be limited and one may also want to limit the
handover complexity, whence we propose a new class of mobility-driven
greedy association policies. The greedy policies are based on defining
a handover support set, which constrains both the possible handovers
and the complexity/information requirements. In a setting where base
station locations follow a Poisson point process, we show that the performance of such handover processes follows a continuous-time Markov
process which can be analyzed using complex variable techniques. This
enables one to explore the optimization size/shape of the handover support
set for mobility-driven greedy handover strategies and their relative
performance compared to traditional association policies.