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A discrete Fourier transform (DFT) modulated filter bank (FB) transceiver architecture is considered which can be used for both spectrum sensing and spectrum access in cognitive radio systems operating in delay dispersive fading channels. A simple post-detection integration at the secondary user receiver using the FB output signals is employed for signal demodulation of differential phase-shift keying...
Due to the increasing demand for the spectrum, the cognitive was proposed to improve the underutilization of the radio spectrum. Under this condition, the secondary users are allowed to share spectrum with the licensed primary user without causing harmful interference to the network. In this paper we studied the interference modeling under two interference management's scheme which is the power control...
Wideband Code Division Multiple Access (WCDMA) is an air interface standard specially designed for third generation (3G) mobile networks to provide low data rate voice services to high data rate multimedia services. But different types of multipath fading, multi-access and co-channel interferences put a limit on overall system performance. The mechanism of power control provides a best alternative...
In last two decades there has been tremendous efforts for research of digital wireless communication system. The coming generation of wireless communication system is demanding for better quality of service with high spectral efficiency and data rate. To meet the demand of high data rate transmission with good quality a novel system is available i.e. multi-carrier Code Division Multiple Access (MC-CDMA)...
The extrinsic information transfer function of multi-user detection for synchronous CDMA is evaluated depending on the load of the system and the signal to noise ratio. This transfer function is used to discuss the benefits of putting redundancy into spreading or coding. Finally, it is shown how low-density parity-check codes can be designed for a specific system.
This paper proposes a new spatial and temporal (S/T) pre-equalization technique for time-division-duplex (TDD) mobile multimedia communication systems. Base station (B S) employs an adaptive array antenna (AAA) and an adaptive decision feedback equalizer (DFE) for up-link signal reception. The weight vectors for the up-link AAA and DFE are also used for pre-equalization of signal to be transmitted...
In this paper, new polyphase sequences and a sequence generation method are suggested. The correlation properties of the sequences are investigated. These sequences have good correlation properties. Since the suggested generation method consists only of integer sums and modular techniques, sequence generation is also easy. The performance of the sequences is investigated for QS-CDMA systems in frequency...
The geometry of room acoustics is such that the reverberant signal can be seen as the same waveform emitted from multiple locations. In analogy with the rake receiver from wireless communications, we propose several beamforming strategies that exploit, rather than suppress, this additional spatio-temporal diversity. Unlike earlier work in the frequency domain, time domain designs allow to shape the...
Estimation techniques for the signal-to-noise ratio play an increasingly vital role in the effective operation of wireless communication systems. This paper presents stochastic models and estimation algorithms for the average received signal-to-interference-noise ratio (SINR) in local fading area channels with a finite random number of scatterers for wireless single-input-single-output (SISO) and...
In this paper, we introduce a generalized decorrelating discrete-time RAKE receiver for MIMO systems (MIMO GD-DTR). The MIMO GD-DTR system is a combination of two other advanced MIMO RAKE reception methods: the jointly decoding generalized rake receiver (JD-GRAKE) and the MIMO decorrelating discrete-time RAKE reception (MIMO D-DTR). The JD-GRAKE has been proposed for correlated interference suppression...
Using chaotic sequences for spreading is a new approach for optimising the BER (Bit Error Rate) performances in the DS-CDMA (Direct Sequence - Code Division Multiple Access) systems. This paper presents the use of a very well known family of PWAM (Piece-Wise Affine Markov) maps, namely (n, t) - tailed shifts maps, and their optimum quantized versions. This optimisation involves the variance minimisation...
In this paper, we study DFT bank transceivers with filter length longer than the block size. Given a fixed transmit (or receive) prototype filter, it has been shown recently that we are able to design the receive (or correspondingly transmit) prototype filter so that the signal to interference ratio (SIR) is maximized for multipath fading channels. However only the transmit (or receive) filters are...
Pilot contamination has become a major capacity bottleneck in massive MIMO systems. To mitigate pilot contamination, a novel cell sectorization-based pilot assignment (CS-PA) scheme is proposed in this paper. By separating the users that transmit the same pilot in physical space, the pilot transmitted by the user in each sector is orthogonal with pilots transmitted by the users in adjacent sectors...
Wireless sensor networks (WSN) are used in many fields such as industrial control, building automation, environmental monitoring, etc. IEEE 802.15.4 standard defines the features of MAC layer and physical layer for WSN. Many analytical models studied the performance of the multihop IEEE 802.15.4 networks under the assumption of ideal wireless channel, and they did not consider the effect of imperfect...
Statistical modeling of interference power is a useful tool to study and investigate the outage probabilities in homogeneous and heterogeneous cellular networks. Also, the ability to analyze and accurately predict the impact of interference via the use of an interference model is an essential way to improve the average throughput (cell edge throughput). There have been several statistical models for...
The conventional receiver for DS-CDMA communications is the RAKE receiver which is a (linear) matched filter (MF), matched to the operations of spreading, pulse shape filtering and channel filtering. Such a MF maximizes the Signal-to-Interference-plus-Noise Ratio (SINR) at its output if the interference plus noise is white noise. This may be approximately the case if user-dependent scrambling (aperiodic...
In this paper, we have explored a potential spectrum sharing technique based on the power allocation in fading environment under transmit power constraint at secondary user/cognitive user (SU) and the interference power constraint at the primary user (PU). In addition to this, we have also analyzed the outage capacity limits over the fading channel, when the partial channel state information is provided...
In this paper, the various spectrum sharing schemes between the Primary Radio (PR) link and Cognitive Radio (CR) link have been analyzed. Also the ergodic capacities of PR and CR links under Constant Power (CP) and Water filling (WF) power control policies have been analyzed. In order to mitigate the interference caused to the PR receiver from the CR transmitter, interference temperature constraint...
In this paper, we propose an interference power constraint method using measurement-based spectrum database for high efficient spectrum sharing. The spectrum database is constructed from measurement radio environment information measured by secondary users (SUs) with mobility, and stores radio environment maps (REMs). This paper focuses on a databaseaided communication parameter adaption method which...
Energy efficiency has become one of the key performance indicators for 5G wireless networks. Coordinated multipoint (CoMP) transmission/reception and multiinput single-output (MISO) are two technologies which can achieve higher energy efficiency in heterogeneous networks (HetNets) compared to conventional single-input single-out (SISO) systems. CoMP improves energy efficiency by joint transmission...
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