Performance of Multi-User Transmitter Pre-Processing Assisted Multi-Cell IDMA System for Downlink Transmission

Abstract

In this paper, we present the performance of multi-user transmitter pre-processing (MUTP) assisted coded-interleave division multiple access (IDMA) system over correlated frequency-selective channels for downlink communication. We realize MUTP using singular value decomposition (SVD) technique, which exploits the channel state information (CSI) of all the active users that is acquired via feedback channels. We consider the MUTP technique to alleviate the effects of co-channel interference (CCI) and multiple access interference (MAI). To be specific, we estimate the CSI using least square error (LSE) algorithm at each of the mobile stations (MSs) and perform vector quantization using Lloyd's algorithm, and feedback the bits that represents the quantized magnitudes and phases to the base station (BS) through the dedicated low rate noisy channel. Finally we recover the quantized bits at the BS to formulate the pre-processing matrix. The performance of MUTP aided IDMA systems are evaluated for five types of delay spread distributions pertaining to long-term evolution (LTE) and Stanford University Interim (SUI) channel models. We also compare the performance of MUTP with minimum mean square error (MMSE) detector for the coded IDMA system. The considered TP scheme alleviates the effects of CCI with less complex signal detection at the MSs when compared to MMSE detector. Further, our simulation results reveal that SVD-based MUTP assisted coded IDMA system outperforms the MMSE detector in terms of achievable bit error rate (BER) with low signal-to-noise ratio (SNR) requirement by mitigating the effects of CCI and MAI.

Security Improvement in Next GenerationWireless System by Interleaverin Transceiver Structures

“…For the MIMO-IDMAsystem with dual-polarised antennas, the channel matrix is generally described in terms of the vertical and horizontal polarizations. The transmit and receive relationship between the vertical and horizontal polarizations of the antennas at the BS and MS are described by the channel state information matrix H. This can be modelled with the help of Figure 2 as given by [12,18] H dp = h vv h vh h hv h hh (6) The backdrop of dual-polarised antenna structures suggest the ability to separate the vertical and horizontal polarisation components as described by the cross-polarization discrimination (XPD) factor which is directly related to the random component of the channel. XPD is the main parameter that features the information leakage from one polarisation to another induced by the channel imperfections.…”

“…The proposed technique in [3] is in contrast to the code-division multiple access (CDMA), where users are separated through user-specific spreading sequences [4]. In comparison with CDMA, the IDMA has significant advantages such as less complex detection scheme without compromising the diversity gain [5,[6][7][8][9]. Further the IDMA outperforms the CDMA when it is integrated with iterative turbo decoding schemes at the receiver terminal [4,5,8].…”

“…The channel state information at transmitter (CSIT) of MIMO-IDMA has been discussed in [25]. The multiuser transmitter pre-processing (MUTP) has been discussed in [6]. The different channel models for MIMO and fixed wireless system was discussed in [26][27][28][29].…”

Triple-Polarized Multi-User Mimo-Idma System under Correlated Fading Channel

“…Multi-user detection (MUD) techniques are employed at the BS and MS to overcome the effect of MUI. But the limiting factor is the complexity involved in the detection scheme [6]. Therefore to overcome this limitation, transmitter side pre-processing technique to be called as transmitter pre-processing (TP) or multi-user TP (MUTP) is employed in DL communications.…”

“…Therefore to overcome this limitation, transmitter side pre-processing technique to be called as transmitter pre-processing (TP) or multi-user TP (MUTP) is employed in DL communications. Hence, the TP along with the receiver side post processing enables to overcome MUI and inter-antenna interference (IAI) in a DL-MIMO system [6] [22]- [24]. The performance of this pre-processing technique has been investigated in time division duplex (TDD) system [6].…”