Spectrum sensing has been identified as a key enabling cognitive radio (CR) to not interfere with primary users, by reliability detecting primary users’ signals. Based on the OpenAirInterface platform, we performed at EURECOM a sensing demonstration in order to illustrate the spectrum sensing concept in one hand and to assess some of the existing algorithms performances in other hand. The platform is designed for a full software-radio implementation, in the sens that all protocol layers run on the host PCs under the control of a Linux real time operating system. The demonstration is composed of two nodes: a primary user with a varying transmission gain and four possible carrier frequencies, and a secondary user (or CR) user implementing three sensing algorithms (Energy detection, cyclostationarity detection, and model selection based detection). At the second node, the sensing results as well as their corresponding measured signal to noise ratio (SNR) over the four sub-bands are displayed in real time.