Multi-User MIMO Mobile CDMA Uplink System Employing Turbo Coding and Joint Detection Through a Multipath Rayleigh Fading Channel

Abstract

In this paper, a generalized multiple-input multiple-output (MIMO) antenna system that can be fitted to the uplink of a wireless communication system is considered for the general case of multi-user. At the transmitter, the information bits are Turbo coded, then interleaved and passed through a serial-to-parallel converter. The channel is assumed bad urban suffering from multipath Rayleigh fading resulting in inter-symbol and multiple access interferences (ISI and MAI). At the front-end of the receiver, a number of receiving antennas are used followed by a joint multi-user estimator based on the Minimum Mean Square Error Block Linear Equalizer (MMSE-BLE).Computer simulations demonstrate a significant performance improvement in both single user and multi-user cases.

Imperfect cross-correlation and amplitude balance effects on conventional multiuser decoder with turbo encoding

“…Some recent papers [13,15] highlight that the use of frequency-domain processing decreases the complexity of detection algorithms. Moreover, several versions are proposed according to the used type of multiple access (FDMA [13], TDMA [15,16], CDMA [17] or OFDM [18]) and all of them represent enhancements for the existing mobile communications systems. The interleaving procedure [19] used in turbo coding could be optimized and enhanced [20].…”

Performance evaluation for conventional and MMSE multiuser detection algorithms in imperfect reception conditions

“…The extended use of the MIMO technique in the current decade increased the expectations from the multiuser detection [4][5][6]. Moreover, the MIMO application extended the interest to the multiuser detection technique to the intelligent antenna systems [7,8].…”

“…Several research studies have been made in order to determine less complex receiver algorithms and to determine their performances under different propagation conditions [5,9]. The high demand for mobile networks and wireless sensor networks increased the interest on multiuser detection for receivers in the presence of severe fading [5,10] or on a combined solution between multiuser detection and diversity techniques [11]. Iterative decoding algorithms based on turbo decoding principles have also been studied [12,13], as well as evaluation of performances in different fading channel conditions [14] and in combination with space time coding [15].…”

Performance Analysis of MIMO Based CDMA Code Acquisition Over Rayleigh Fading Channels

“…For DS-CDMA systems, the utilizations of MIMO, multi-carrier (MC) and space-time code (STC) have been shown to be able to increase the data throughput and channel capacity [5][6][7][8]. In [6], a turbo receiver for the uplink of a MIMO-CDMA system employing layered space-time transmission was proposed.…”

“…The correctness and effectiveness of the channel estimation and the receiver design for the ST-coded CDMA-MIMO systems were demonstrated. In [8], joint multi-user detection for MIMO-CDMA was considered. The performance was simulated for single user and multi-user cases and the performance for multi-user case was improved.…”