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According to the cost and power consumption of wireless communication receiver under high-precision quantization, this paper discusses the effect on the performance of channel estimation for OFDM systems with low-precision quantization. Theoretical analysis and simulation results show that the low-precision quantization degrades the system performance. However, the optimized channel estimation algorithm...
This paper proposes a novel wireless positioning method based on the time reversal technique, with the pulse width of related function of different channel impulse response as position characteristic parameters. This method uses the related function's pulse width to measure the distance between the mobile terminal and base station, and then exactly locates the mobile terminal with traditional TDOA/TOA...
A new hybrid multiple access scheme called SC-FDMA-IDMA is proposed, which combines IDMA (interleaved division multiple access) and SC-FDMA (single carrier frequency division multiple access). SC-FDMA-IDMA inherits many attractive features of SC-FDMA and IDMA. However, carrier frequency offsets (CFOs) also exist in this system since its inheritance. Moreover, the effect of CFO on the performance of...
OFDM-IDMA scheme has raised lots of research interests recently as it appears to be quite suitable for future broadband wireless transmission. OFDM-IDMA inherits many attractive features of OFDM and IDMA. However, OFDM-IDMA is also sensitive to carrier frequency offset (CFO) due to OFDM Furthermore, the performance of OFDM-IDMA with CFO has not been reported in the literature. In this paper, we investigate...
According to OFDM-IDMA suffers a peak-to-average power ratio (PAPR) problem, in this paper, we propose a hybrid multiple access scheme for LTE uplink, which combines IDMA and SC-FDMA (Single Carrier Frequency Division Multiple Access), named as SC-FDMA-IDMA. This hybrid multiple access scheme inherits many attractive features of SC-FDMA and IDMA. We discuss the performance comparison of SC-FDMA-IDMA...
This paper presents the performance comparison of Single Carrier Frequency Division Multiple Access-Code Division Multiple Access (SC-FDMA-CDMA) and Orthogonal Frequency Division Multiplexing-Code Division Multiple Access (OFDM-CDMA) systems for uplink. We investigate the basic principle and the similarities and differences of these different schemes. According to these schemes, we discuss the performance...
According to the high complexity of pre-coder in single-carrier interleave-division multiple access (IDMA) systems, in this paper, we propose a precoding technique based on time-reversal (TR) for single-carrier IDMA systems. The proposed scheme gets the channel impulse responses (CIR) through time-division duplexing (TDD) mode, and uses the time-reversed version of the CIR to pre-coder the transmitted...
Blind adaptive multi-user detection (MUD) is one of the key technologies in CDMA systems, and there are lots of optimal and suboptimal detection algorithms during which constant modulus algorithm (CMA) is widely used. All these existing detection algorithms are based on the assumption of Gaussian ambient channel noise, however, more and more researches in recent years show that the actual ambient...
This paper presents the performance comparison of interleave division multiple access (IDMA) and code division multiple access (CDMA) systems based on Simulink. We investigate the basic principle that illustrates the similarities and differences of the two different schemes. According to these schemes, we analyze every model function and build simulation platforms for these systems. The simulation...
IDMA can be regarded as a special case of CDMA, where the spreading can be done by an arbitrary low rate channel code equal for all users and the separation can be done by user-specific interleavers. In this paper, we provide the anti-jamming performance analysis of partial band for IDMA systems. First, we investigate the basic principle of IDMA briefly. Then introduce the generation of the partial...
Interleave-division multiple access systems (IDMA) has been extensively studied. In this paper, we present the performance analysis of anti-jamming for IDMA systems. The theoretic analysis and simulation results show that the performance of anti-jamming for IDMA systems is related to spread gain, code-bit rate, and the number of iterations, respectively. And our research work can provide a reference...
The effect of sample-timing error on the bit-error-rate (BER) performance of the interleave-division multiple access (IDMA) systems are studied in this paper. We construct an asynchronous IDMA system model to investigate the effect of sample-timing error caused by the asynchronous transmission from different user ends (UEs) on the BER performance. The theoretic analysis shows that sample-timing error...
In this paper, we propose a channel estimation algorithm for the interleave-division multiple access systems (IDMA) system based on time-reverse (TR) technique (named as TDR-IDMA), which can accelerate the execution of multi-user detection (MUD) algorithm for IDMA systems. In the TDR-IDMA systems, the time-reversed version of channel impulse responses (TR-CIR) is used to perfume the pre-processing...
Interleave-division multiple-access (IDMA) is one of the key multiple access techniques in the new wireless communication systems. In this paper, we investigate the basic principle of IDMA systems, analyze every model function, and build a simulation platform for IDMA systems. It is convenient to set the main parameters of the model of IDMA systems according to the simulation platform, and thus realize...
The effect of channel estimation error on the performance of the interleave-division multiple access (IDMA) systems are studied in this paper. For comparison, a channel estimation approach based on expectation maximization (EM) algorithm is also presented. The theoretic analysis and simulation results show that the variance of the channel estimation error affects the bit-error-rate (BER) performance...
In this paper, we propose a hybrid multiple access scheme which combines interleave division multiple access (IDMA) and code division multiple access (CDMA), therefore, we refer to this scheme as IDMA/CDMA. We employ IDMA technique as the uplink transmission and CDMA technique as the downlink transmission. Thus, IDMA/CDMA can achieve a very simple chip-by-chip iterative multi-user detection (MUD)...
A new channel estimation approach based on expectation maximization (EM) algorithm is proposed for the interleave-division multiple access systems (IDMA). The combination channel estimation is used in the proposed algorithm. The pilot sequences are used to estimate the channel information at the first iteration. The pilot and the soft estimates from the decoders are combined to refine the channel...
In this paper, we propose a downlink transmission and receiving scheme for interleave-division multiple access (IDMA) system based on time-division duplexing (TDD) mode and time-reversal (TR) technique. The proposed scheme uses the time-reversed version of the channel impulse responses (CIR) obtained from the uplink to pre-process the transmitted signal at base station. By exploiting the weak correlations...
In this paper, we propose a fast converging multiuser detection for interleave-division multiple access (IDMA) system based on time-reversal (TR) technique. The proposed algorithm uses the time-reversed version of the channel impulse responses (TR-CIR) obtained from the uplink to process the received signal before the elementary signal estimator (ESE). With the help of the weak correlation of fading...
In this paper, we propose a time reversal (TR) based time division duplex (TDD) interleave-division multiple access (IDMA) scheme (TDR-IDMA). Multiple user interference (MUI) can be greatly suppressed with TR technique. The Turbo-type iterative detection can achieve fast convergence speed with a little additional complexity at base station. From simulation results, we found that only five iterative...
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