Performance analysis of cross- and cigar-shaped urban microcells considering user mobility characteristics

User mobility characteristics and cell shapes in urban microcellular environments are different from those in macrocellular environments because pedestrians walk along streets and radio signals are guided by tall buildings lining both sides of the streets. Urban area microcell shapes follow approximately the street pattern. In this paper, we characterize low-tier user mobility in typical urban microcells: cross-shaped cells and cigar-shaped cells, and then evaluate and compare the two types of microcell. The results show that the more suitable cell shape with respect to handoff traffic and its signaling load is determined by the probability of straight movement at an intersection. On the other hand, blocking probability in low-tier microcells mainly depends on the cell size, not the shape. This framework and its numerical results can be utilized in determining the cell shape and size of urban microcellular systems.