32 $^{!$_{"#$}$}$$_{ }$  $^{!%$_{"#$}$}$  $^{&}$  $^{’}$  Interfering Cell $ BS of Interest  !$_{"#$}$ ( { ! $_{1}$, ! $_{2}$, GLYPH<133> !$_{)}$ , GLYPH<133> !$_{*}$ } ( { $_{1}$, $_{2}$, GLYPH<133> ,  $_{+}$ , GLYPH<133> ,  $_{,}$ } !%$_{"#$}$ ( { !% $_{1}$, !% $_{2}$, , GLYPH<133> !%$_{-}$ , GLYPH<133> , $^{!%$_{.}$}$}  Fig. 1. Geometrical illustration of dividing the cellular network into multiple rings of non-uniform width Δ$_{k}$ .