Space-time block coding for single-carrier block transmission DS-CDMA downlink

Abstract

Abstract-The combination of space-time block coding (STBC) and direct-sequence code-division multiple access (DS-CDMA) has the potential to increase the performance of multiple users in a cellular network. However, if not carefully designed, the resulting transmission scheme suffers from increased multiuser interference (MUI), which dramatically deteriorates the performance. To tackle this MUI problem in the downlink, we combine two specific DS-CDMA and STBC techniques, namely single-carrier block transmission (SCBT) DS-CDMA and time-reversal STBC. The resulting transmission scheme allows for deterministic maximum-likelihood (ML) user separation through low-complexity code-matched filtering, as well as deterministic ML transmit stream separation through linear processing. Moreover, it can achieve maximum diversity gains of ( + 1) for every user in the system, irrespective of the system load, where is the number of transmit antennas, the number of receive antennas, and the order of the underlying multipath channels. In addition, it turns out that a low-complexity linear receiver based on frequency-domain equalization comes close to extracting the full diversity in reduced, as well as full load settings. In this perspective, we also develop two (recursive) least squares methods for direct equalizer design. Simulation results demonstrate the outstanding performance of the proposed transceiver compared to competing alternatives.Index Terms-Block transmission, direct-sequence code-division multiple access (DS-CDMA), equalizer design, frequency-selective fading channels, multiple-input-multiple-output (MIMO), space-time block coding (STBC).

Space-Time Block Coding for Uplink Single-Carrier CDMA with Joint Detection in the Frequency Domain

“…STBC 2x1 also loses a significant part of its spatial diversity gain with respect to MRC 1x2. Figure 8 compares the performance of SC-CDMA and SCBS-CDMA [19], [20] for different user loads. In the case of a singlepath channel, both systems are orthogonal in the users and perform equally well.…”

“…The combination of STBC with the SC-based air interfaces has only been addressed very recently. Papers [19] and [20] combine STBC with SCBS-CDMA. Since the SCBS-CDMA scheme is orthogonal in the users (both for uplink and downlink), deterministic ML user separation through low-complexity code matched filtering and ML ST multi-stream separation through linear decoding can be consecutively applied without any performance loss with respect to the optimal ML joint multiuser detector and ST block decoder.…”

Precursor inter-symbol interference removal by block transmission-based time-reversed equalization

“…In [6], an improved receiver structure is proposed by trellis-based conflict resolution. Time reversal is also used in the context of antenna arrays [7], multiple-input multiple-output systems [8], and space-time block coding [9].…”

Frequency domain equalization space-time block-coded CDMA transmission system

“…A different structure for STBC single carrier CDMA transmission system based on chip-interleaved block-spread (CIBS) CDMA [17] was proposed in [18]. The structure in [18], though promising excellent performance, incurs in a relatively high computational complexity to update the equalizer coefficients [19].…”