Statistics of macrocell-synchronous femtocell-asynchronous users? delays for improved femtocell uplink receiver design

In a typical macrocell network, the mobile users are synchronized to the macrocell base station (mBS), where users further away to the mBS transmit their signals earlier. In such a network, the signals of the macrocell users arrive at a femtocell base station (fBS) asynchronously, which may yield interference problems such as inter-carrier-interference in orthogonal frequency domain multiple access (OFDMA) systems. In this letter, statistics of the arrival times of macrocell-synchronous femtocell-asynchronous mobile users' signals to an fBS is derived (conditioned on the fBS-mBS distance), and its implications on the femtocell uplink receiver design are briefly discussed.