A CDMA-MIMO system with multiple-dimension-decorrelating-detectors

Sequential detection CDMA multi-user receiver

“…In addition, the smaller the size of matrix P; the smaller the noise amplification factor a [17][18][19] because the regularity of matrix P represented by the condition number G (of matrix C) improves considerably as the matrix size decreases for a given core sequence length (see Section 5.2). This fact contributes the reduction in noise power jDb k j 2 expected after the second stage.…”

“…This important factor is examined in conjunction with noise amplification of DD by the preceding works of this paper [17][18][19].…”

“…In these previous works, the relation between process gain L (spreading sequence length) and the number of active users K has been treated very little. This important factor is examined in conjunction with noise amplification of DD by the preceding works of this paper [17][18][19].…”

“…This paper intends to improve the performance of multi-user receivers using LT techniques, without using coding methods such as the Turbo code. Assumed are in addition such factors that accurate pilot responses (signatures made of spreading sequences and channel gains) for all the users are given, a quasi-synchronization is maintained by controlling the transmit timing of each user, with a closed-loop control [20] and an enveloped spreading sequence which is made by surrounding the core sequence by guard sequences to avoid ISI [17][18][19] is used at the transmitter. In the operation of DD or MMSE, the performance degrades with the AWGN noise amplification (including interference noise for MMSE).…”