# 9.8 UL C/I calculation

The C/I calculation in <span data-highlighted="true" data-vc="highlighted-text"><span class="_kqswh2mm"><span class="_5pioz8co _189e1dm9 _1il9buyh _19lc184f _d0altlke" data-testid="definition-highlighter">UL</span></span></span> is calculated so that *C(j,k)* is the received power from the *<span data-highlighted="true" data-vc="highlighted-text"><span class="_kqswh2mm"><span class="_5pioz8co _189e1dm9 _1il9buyh _19lc184f _d0altlke" data-testid="definition-highlighter">UE</span></span></span><sub data-renderer-mark="true">j,k</sub>* at the *j*-th <span data-highlighted="true" data-vc="highlighted-text"><span class="_kqswh2mm"><span class="_5pioz8co _189e1dm9 _1il9buyh _19lc184f _d0altlke" data-testid="definition-highlighter">BS</span></span></span>.

 [![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/zBh98M7PJzxlKZEI-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/zBh98M7PJzxlKZEI-image.png) (Eq. 54)

where *P*<sub data-renderer-mark="true">t</sub> is the transmit power of the <span data-highlighted="true" data-vc="highlighted-text">UE</span> in dBm (see <span data-highlighted="true" data-vc="highlighted-text">UL</span> Power control below) and effective\_pathloss is defined as in Section ‎7.6.1..

The total interference to a <span data-highlighted="true" data-vc="highlighted-text">UL</span> cellular system is derived from

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/2o0hEN93rdgc8mVB-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/2o0hEN93rdgc8mVB-image.png) (Eq. 55)

where

- *I<sub data-renderer-mark="true">inter</sub>* is the interference coming from UEs of the same system but from adjacent cells, i.e. the inter-system interference from other cells. Since a fully orthogonal system is assumed, only UEs which transmit in the same frequency subcarriers will introduce interference to each other, hence only UEs in other cells with the same *k* index are considered;
- *I<sub data-renderer-mark="true">ext</sub>(j,k)* is the interference from external interfering system(s) in adjacent channel;
- *N* is the noise floor.

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/rYcagTu6lKc8q1Ar-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/rYcagTu6lKc8q1Ar-image.png) (Eq. 56)

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/wnPwHgWyW96iQAhs-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/wnPwHgWyW96iQAhs-image.png) (Eq. 57)

*I<sub data-renderer-mark="true">ext</sub>(j,k)* is the interference to the the victim <span data-highlighted="true" data-vc="highlighted-text">BS</span><sub data-renderer-mark="true">j</sub> from N interfering link transmitters (ILT), where

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/RjtEW36InovHYuhV-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/RjtEW36InovHYuhV-image.png) (Eq. 58)

for each of the victim <span data-highlighted="true" data-vc="highlighted-text">BS</span><sub data-renderer-mark="true">j</sub>’s frequency where the <span data-highlighted="true" data-vc="highlighted-text">UL</span> information is received. The ILT can be any generic systems or a <span data-highlighted="true" data-vc="highlighted-text">BS</span>/UEs of a cellular system.

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/vQRbLhF4j7IOlplC-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/vQRbLhF4j7IOlplC-image.png) (Eq. 59)

at the victim system frequency. Where *N<sub data-renderer-mark="true">RB</sub>* is the number of RBs (i.e. subcarriers) requested per <span data-highlighted="true" data-vc="highlighted-text">UE</span>, and M is the maximum number of RBs per <span data-highlighted="true" data-vc="highlighted-text">BS</span>.

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/75HBIuLIVhijA94Y-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/75HBIuLIVhijA94Y-image.png)(Eq. 60)

where *NoiseFigure<sub data-renderer-mark="true"><span data-highlighted="true" data-vc="highlighted-text">BS</span></sub>* is the noise figure of a <span data-highlighted="true" data-vc="highlighted-text">BS</span>.