  For real-time traffic, the link quality and call blocking probability (both
derived from coverage probability) are realized to be poor for cell edge users
(CEUs) compared to cell center users (CCUs) as the signal reception in the cell
center region is better compared to the cell edge region. In heterogeneous
networks (HetNets), the uncoordinated channel access by different types of base
stations determine the interference statistics that further arbitrates the
coverage probability. Thus, the spectrum allocation techniques have major
impact on the performance of CCU and CEU. In this paper, the performance of
CCUs and CEUs in a random two-tier network is studied for two spectrum
allocation techniques namely: 1) co-channel (CSA), and 2) shared (SSA). For
performance analysis, the widely accepted conception of modeling the tiers of
HetNet using independent homogeneous Poisson point process (PPP) is considered
to accommodate the spatial randomness in location of BSs. To incorporate the
spatial randomness in the arrival of service and to aid the load-aware
analysis, the cellular traffic is modeled using spatio-temporal PPP. Under this
scenario, we have developed an analytical framework to evaluate the load-aware
performance, including coverage and blocking probabilities, of CCUs and CEUs
under both spectrum allocation techniques. Further, we provide insight into
achievable area energy efficiency for SSA and CSA. The developed analytical
framework is validated through extensive simulations. Next, we demonstrate the
impact of traffic load and femto access points density on the performance of
CCUs/CEUs under CSA and SSA.
