Iterative IDMA Receivers with Random and Tree Based Interleavers

In Interleave-Division Multiple-Access (IDMA) scheme, user specific interleavers are employed as the only means for user separation. It is well established fact that these interleavers must have property of orthogonality amongst each other. The interleavers are, therefore, referred has the heart of IDMA system. The researchers have proposed various non-orthogonal interleavers in the literature which are easy to generate and have near-zero collision property. The Tree Based Interleaver (TBI) is one of those non-orthogonal interleavers which not only reduces the bandwidth requirement in comparison to that required in case of Random Interleavers (RI) but also reduces computational complexity drastically when compared with that of master random interleavers. The memory requirement at receiver end and its cost problem are also solved by tree based interleaver with further reduction of the amount of information exchange between mobile stations and base stations required to specify the user-specific interleavers. In this paper, the performance analysis of iterative IDMA receivers have been evaluated with BPSK & QPSK modulation techniques employing tree based interleavers and random interleavers, as representative of non-orthogonal interleaver, in uncoded and rate ½ covolutionally coded conditions with Additive White Gaussian Noise (AWGN) channel. In the simulation results, the IDMA system with QPSK modulation techniques employing TBI outperforms the Random Interleavers optimally.

2013 International Conference on Communication Systems and Network Technologies, 2013

The Interleave-Division Multiple-Access (IDMA) scheme is known for property of orthogonality amongst its user-specific interleavers. The interleavers are, therefore, referred has the core heart of IDMA Transceivers. Nowadays , the IDMA scheme is being thought as a strongest candidate for radio access in cellular mobile communication systems. It is attractive for wireless access due to its numerous advantages over TDMA, FDMA and CDMA and other multiple access schemes. In this paper, IDMA system is being simulated using random interleaver foe each user. On comparing various spreading techniques including repition, Gold code and Walsh code spreading, it is observed from simulation results, that the performance is almost similar for all the spreading mechanisms. However, from implementation point of view, repition spreading is concluded as optimum mechanism because it requires less memory, less computational complexity, easy implementation and also defines larger number of users as compared to Gold code and Walsh code for same spreading length. In this paper, the performance analysis of iterative IDMA receivers have been evaluated with BPSK & QPSK modulation techniques employing random interleavers in uncoded and rate ½ convolutional coded conditions with Additive White Gaussian Noise (AWGN) channel. During the simulation, it has been observed that IDMA system with QPSK modulation techniques employing QPSK outperforms its counterpart BPSK optimally.

2017

Transmitting multiple copies of signal to minimize fading effect is known as diversity. It is effectively and very commonly used in communication systems to overcome performance degradation due to interference and fading. In this paper, receiver diversity technique is used to overcome fading effect in IDMA scheme with random interleaver, tree based, and Invert tree based interleaver (ITBI). Simulation results illustrates significant performance improvement of IDMA system with receive diversity. It has been observed that ITBI gives comparable performance to that of random and tree based interleaver, however, it presents noteworthy reduction in bandwidth and memory requirement.

2018

This paper provides a review on the IDMA (Interleave Division Multiple Access) technology in wireless communication system based on Interleaver. In this paper, IDMA technique is proposed in AWGN channel. IDMA is a multiuser scheme in which chip Interleavers are the only means of user separation. The IDMA performance in terms of bit error rate, error rate is discussed. Here comparision with different sources is done on the basis of error rate and various different parameters.

Few basic requirements for future wireless 4G systems includes low receiver cost, decentralized (i.e. asynchronous) control, simple treatment of ISI, cross cell interference mitigation, diversity against fading, power efficiency (long battery life), multimedia services, high user number, high throughput and high spectral efficiency. All theses factors mentioned are not fulfilled by any multiple access techniques at present. Interleave-Division Multiple-Access (IDMA) is a technique, which provides better result during simulation when applied with at least few of the future mobile communication requirements. IDMA employs interleavers as the only means in order to distinguish the users. This paper provides a comprehensive study of IDMA technique with orthogonal interleavers. . Index Terms--IDMA, Tree Based Interleaver, Multiple Access Interference.

Ijca Special Issue on Wireless Communication and Mobile Networks, 2012

In recent years, the Interleave-Division Multiple-Access (IDMA) scheme has attracted the attention of researchers to be a promising candidate for next generation networks. And Since then numerous technical papers about IDMA have been published in the literature. In this paper, we have simulated the IDMA scheme with various interleavers and modulation mechanism to establish the fact that tree based interleaver along with QPSK modulation mechanism performs better than other mechanisms. It has also been shown that the tree based interleaver is the optimum interleaver for IDMA receivers because it is the best solution to fading at low cost and without requirement of extra bandwidth.

International Journal of Engineering Research and, 2015

In recent days, on the horizon of wireless world, newly proposed multiple access scheme known as Interleave-Division Multiple-Access (IDMA). A method to enhance the performance of IDMASystem Low density parity check (LDPC) codes can be applied to IDMA system, called LDPC-Coded IDMA System, which is presented recently for combing the advantages of LDPC and IDMA. We use regular LDPC coder is used. In this paper we compare coded and uncoded IDMA environment. Performance of coded LDPC-IDMA is using with random interleaver & tree based interleaver. During the simulation, it has been observed that tree based interleaver demonstrate the similar bit error rate (BER) performance to that of random interleaver and also compare to half rate ldpc and convolution coder using Random and Tree based interleaver using BPSK modulation technique in AWGN environment. This paper shows that ldpc-idma is better compare to convolution coder.

2010

In recently proposed multiple access techniques such as IDMA and OFDM-IDMA, the user separation is done by user specific interleavers in contrast to conventional CDMA scheme where user separation is assured with user-specific signature sequences. The user specific interleavers must demonstrate minimum probability of collision amongst each other in addition to other merits including minimal consumption of bandwidth, least hardware for their generation, and least memory requirement. Previously, random interleaver and other interleavers proposed by researchers is still leaving some space for further research leading to optimality of interleavers. In this paper, we propose a novel interleaver based on prime numbers for generation of user specific interleavers to remove the problem of high consumption of bandwidth. The simulation results demonstrate the optimal performance of prime interleaver (PI) apart from other merits in comparison to random and other interleavers.

2007

Interleave Division Multiple Access (IDMA) is a multiuser scheme which enables user separation on the basis of interleavers. Interleaver design can allow the IDMA system to approach near Shannon limits of channel capacity. Interleaver combats against Intersymbol Interference (ISI), channel fading and all sorts of noises. In addition, interleavers provide security to the system users. Designing the random interleaver provides a solution for all impairments but they are generally considered computationally heavy. In this paper, an efficient approach has been developed for design of user specific random block interleavers. This design approach reduces the complexity for developing interleaving patterns and is computationally economical.