1. A method of estimating interference signal code power (ISCP) and noise variance for wireless communication, the method comprising: performing channel estimation using a pre-agreed code sequence to generate a channel impulse response, the channel impulse response comprising W channel coefficients; selecting N smallest channel coefficients out of the W channel coefficients; computing an average power of the N smallest channel coefficients; and applying a scaling factor to the average power to compute the ISCP and noise variance.