Impact of Scrambling-Exact Channel Estimation on HSDPA MIMO
Multiple-Input Multiple-Output (MIMO) antenna systems require a separate pilot signal for each transmitting antenna for enabling the receiver to measure all physical channels separately. As scrambling operates with pseudorandom sequences the auto-correlation is quasi-orthogonal with small deviations from exact orthogonality. In this paper, the impact of these deviations is investigated, which is important especially for estimating the channel impulse response. Therefore, an analytical approach beyond simple correlation is proposed, taking into account the full scrambling sequence.