Abstract:

In order to eliminate the impact of pilot signals in Femto system on the accuracy of cochannel interferencedetection,a novel algorithm named differential phase-rotation interference detection ( DPRID) is proposed. In this algorithm,according to the equal 2-norm characteristic of the pilot signal,the received signal is rotated toequate the components of the pilot,and the channel in frequency domain is estimated according to the characteristicthat the mean interference plus noise is zero. Thus,the contribution of the pilot signal to the received signal iseliminated and the power of cochannel interference plus noise can be directly estimated. With the introduction ofdifference calculation,the statistical data amount increases,both the enhancement in accordant direction and thecounteraction in reverse direction degrade,and most information can be acquired from the pilot signal. Simulatedresults indicate that the proposed DPRID algorithm outperforms the orthogonal interference detection ( OID) algorithm,with a variance of relative estimation error of 9.84dB and a relative estimation error of 4.35dB when singleantenna is configured.

Key words: interference detection, phase rotation, Femto system, difference calculation