Fast scan of NB-IoT signals in networks

A method for fast detection scan of Narrowband-Internet-of-Things (NB-IoT) signals in a single run of Narrowband Primary Synchronization Signal (NPSS) search performed by a user equipment (UE) by applying a higher sampling rate than 240 kHz and observing a received signal at a receive bandwidth relative to a NB-IoT signal bandwidth (BW) within a frequency interval −BW/2−MΔ≤f≤MΔ+BW/2, Δ=100 kHz to support a simultaneous scan of E-UTRA absolute radio frequency channel number (EARFCN)−M≤m≤−1 and 1≤m≤M in addition to the EARFCN for m=0 relative to a carrier frequency by the UE, whereas m is a EARFCN offset, wherein a set of 2M+1 NB-IoT signals each having a different EARFCN are observed simultaneously and M is a natural number and 2M+1 indicates a number of observed channels, and by using a wider bandwidth as well as a fast Fourier transformation to transform time domain samples into frequency domain samples and using special auto-correlations in the frequency domain to detect carrier frequency candidates which carry the NB-IoT signals simultaneously;

• wherein the method comprises a first stage, at which an average part of a cyclic prefix of a received baseband signal is removed;
• and a second stage, at which time domain vectors of N IQ samples of the received signal without the cyclic prefix are collected in time, whereas N is chosen such that an average time difference of the time domain vectors is equal to one Long Term Evolution Orthogonal Frequency Division Multiplexing (LTE OFDM) symbol, whereas N is the length of the vector.